JPH0222328B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for automatically measuring various characteristics of an optical system, such as spherical refractive power, cylindrical refractive power, and its axial direction, prismatic refractive power, and its base direction. The principles and embodiments of the present invention described below mainly relate to a method and apparatus for measuring the above-mentioned characteristics of eyeglass lenses, but this invention applies to a so-called lens meter that measures the various characteristics of eyeglass lenses. This does not mean that it is applied only to the above, but it can also be used to measure the above-mentioned characteristics of lens optical systems widely used in optical instruments.

In recent years, various measurement principles and devices have been proposed for so-called automatic lens meters that automatically measure various optical properties of eyeglass lenses, such as their spherical refractive power, cylindrical refractive power, and their axial directions. . One of them is US Pat. No. 3,880,525. This device based on the U.S. patent makes parallel light incident on the lens to be tested parallel to its optical axis, and attempts to determine the optical characteristics of the lens to be tested from the polarization of the emitted light. , a mask having a point aperture is arranged so that the point aperture is located off the optical axis of the lens to be tested, a detection surface is provided a predetermined distance away from the mask in the optical axis direction, and the detection surface passes through the aperture of the mask. The coordinates of the point where the light flux reaches the detection surface are detected, and the direction and amount of deflection of the light emitted from the test lens are calculated by comparing the detected coordinates with the coordinates of the aperture on the mask. It is configured to know the optical characteristics of the detection lens. In this case, at least three openings in the mask are required to obtain the necessary information.

In the device according to this US patent, it is necessary to accurately detect the point-to-point correspondence between the apertures on the mask and the arrival points on the detection surface, and each aperture must be arranged in a planar manner so that the emitted light beam must be made to be a non-coplanar luminous flux. For this purpose, a two-dimensional plane must be scanned, and the apparatus as a whole inevitably becomes expensive. Furthermore, it is necessary to solve five-dimensional simultaneous equations using coordinate information of at least three points, and the calculation mechanism becomes complicated and expensive.

Furthermore, since point image detection is used, if dust or the like adheres to the lens to be tested or the detection surface, the point image becomes undetectable and measurement becomes impossible. U.S. Patent No.
There is a device described in No. 4180325. This device is
Multiple beams of light passing through the mask aperture are intermittently blocked by a rotating disk with a special pattern consisting of transparent and opaque areas, and by making the time at which each beam reaches the detector differ, the light beams on the mask are The configuration is such that it is not necessary to determine the correspondence between the aperture and the light flux on the detection surface. However, in this device, the pattern on the rotating disk is very complex, and detection of its rotational position is very important. There are major problems in terms of construction and production.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical property measuring device that solves the above-mentioned problems in conventional devices and allows detection and subsequent calculations to be performed relatively easily.

In other words, the optical characteristic measuring device for an optical system of the present invention selects a planar light beam (or a "twisted" planar light beam in the case of cylindrical refractive power) by selecting a light beam that has passed through the optical system with a light flux limiting mask having two linear patterns. ) is an optical phenomenon in which the interval traveling direction of the light beam and its inclination change depending on the optical characteristics of the optical system, but the flatness (linearity of the projected image) is never impaired. It was developed based on the principle of A light flux limiting mask consisting of a plurality of parallel straight line patterns is arranged in each optical path, and the straight line patterns are arranged in different directions.
It is more accurate than conventional equipment by detecting a point, calculating the linear equation of this projected image, and measuring the optical characteristics of the optical system under test from changes in the tilt, position, and pitch of the linear pattern image. Another object of the present invention is to configure an optical characteristic measuring device for an optical system that has a high calculation processing speed.

Furthermore, a second object of the present invention is to further divide the light flux that has passed through each of the light flux limiting mask means in such a measuring device into two, and to allow the two divided measurement light fluxes to intersect with each other on an optically conjugate detection surface. Alternatively, it is an object of the present invention to provide a device for measuring optical characteristics of an optical system that allows the light to be incident on a line sensor arranged parallel to each other and has no moving parts, is inexpensive, and has high precision and high speed. .

Furthermore, a third object of the present invention is to arrange parallel linear patterns having different wavelength selection characteristics on one mask means in different arrangement directions, instead of placing the above-mentioned two light flux limiting masks in the two measurement optical paths. It is an object of the present invention to provide an optical characteristic measuring device for an optical system which is configured as follows, has no moving parts in one measurement optical path, is inexpensive, and has high precision and high speed.

Furthermore, a fourth object of the present invention is to form a plurality of parallel linear patterns on one mask means, place only one mask means in the measurement optical path, and rotate the mask means itself or By rotating the incident light flux passing through the test lens to emit a limited light flux passing through the test optical system, and detecting this emitted light, a high-accuracy, high-speed optical system optical characteristic measuring device similar to the one described above can be achieved. Our goal is to provide the following.

The principle of the present invention will be explained below.

When parallel light rays are incident on a spherical lens, a cylindrical lens, or an astigmatic lens, the light rays are refracted according to the refractive properties of the lens. Here, a spherical lens is a lens consisting of two spherical surfaces, a cylindrical lens is a lens in which at least one surface is a cylindrical surface, and an astigmatic lens is a lens in which at least one surface is a toroidal surface. This is well known. Now, a toroidal surface consists of a principal meridian with the largest radius of curvature and a principal meridian with the smallest radius of curvature, which are orthogonal to each other. A spherical surface is considered to be a toroidal surface where two orthogonal curved surfaces have the same radius of curvature, and a cylindrical surface is considered to be a case where one curved surface has an infinite radius of curvature. Therefore, spherical surfaces and cylindrical surfaces can be considered as special cases of toroidal surfaces. In the following explanation of the principle of the present invention, an astigmatic lens made of a toroidal surface will be taken as an example, and as a special case, a spherical lens,
We will be dealing with cylindrical lenses.

When parallel rays are incident on a test lens, which is an astigmatic lens, and the rays are considered after refraction, it is known that if the incident ray is a circular ray bundle, the exit ray will be an elliptical ray bundle, but the incident ray When is a straight ray bundle, the exit ray bundle becomes a planar bundle of rays (in the case of cylindrical refractive power, it becomes a "twisted" planar ray bundle), and the traveling direction and inclination of the ray bundle depend on the optical characteristics of the optical system. However, the fundamental property is that the projected image onto a plane perpendicular to the incident parallel rays is always a straight line. Here, the refractive characteristics are the refractive power of the two principal meridians with the maximum and minimum radii of curvature forming the toroidal surface of the test lens, and the inclination of these two principal meridians from a predetermined reference line. This is a prism amount representing the angle and the amount of deviation between the geometric center and the optical center of the lens to be tested or the amount of setting deviation of the lens to be tested.

However, when a mask is placed just in front of the lens to be tested and various restricted ray bundles are made incident, and the output ray bundle is observed, other refractive characteristics, that is, two shape factors in both refraction directions, are required. will be added.

The addition of this new refractive characteristic means that the relationship between the incident ray bundle and the exit ray bundle changes due to a difference in at least one of the radius of curvature of the first surface, center thickness, and refractive index of the lens to be tested. There is. This shape factor adds unnecessary uncertainty to the measurement of the refractive properties that the present invention attempts to measure. The addition of this shape factor can be avoided by limiting the refracted ray bundle after passing through the lens to be tested. That is, a general circular parallel beam is made incident on the test lens, and an elliptical beam that is refracted by the test lens according to its refraction characteristics is restricted by passing through a certain aperture pattern. By detecting this limited light beam, it is possible to know the refraction characteristics that are not affected by the shape factor. Thus, in the present invention, the mask means having the aperture pattern needs to be placed behind the lens to be tested.

Referring to FIG. 1, a light beam 1 emitted from a light source LS is made into a parallel light beam by a collimator lens CL. The lens T to be tested, which has a first principal meridian R ₁ having the minimum radius of curvature and a second principal meridian R ₂ having the maximum radius of curvature, has its optical axis O' from the measurement optical axis O perpendicular to the measurement optical axis. On the X-Y plane, Y within that plane
It is shifted by E _V in the axial direction and E _H in the X-axis direction, and the meridian R ₂ is arranged at an angle of θ with respect to the X-axis. Also,
A mask MA is placed a distance Δd behind the test lens T on the measurement optical axis O, with its center aligned with the optical axis O.

This mask MA contains at least 2 of Pitch P.
The opening is formed such that a group of parallel straight lines L consisting of book straight lines intersect with the x-axis at an inclination m.

The light beam that passes through the test lens T and is refracted by the refractive characteristics of the test lens is restricted by the mask MA, passes only through the aperture pattern, and becomes a restricted light beam. The position of the focal line F ₁ of the first principal meridian R ₁ of T and the focal line F ₂ of the second principal meridian R ₂
converges to the position. Considering the detection plane x-y plane between the focal line F ₁ and the mask MA, on this detection plane, the group of parallel straight lines L, which is the aperture pattern of the mask MA, projects the group of parallel straight lines L' of the pitch P'. form,
Its slope from the x-axis changes to M. Here, the slope M is expressed by the following equation.

M=m{1-d(sin ² θ/Z ₁ +cos ² θ/Z ₂ )
}+d1/ _Z2-1 / _Z1 ) sinθcosθ/md(1/ _Z2-1 /
Z ₁ ) sin θ cos θ − d (cos ² θ/Z ₂ + sin ² θ/Z ₁ ) + 1...
(1) Also, pitch P′ is It is expressed as

Here, Z ₁ is the distance from the mask MA to the first focal line F ₁ , and Z ₂ is the distance from the second focal line F ₂ .

From equations (1) and (2), if we trace the changes in the group of parallel straight lines by focusing only on their slope and pitch, we can see that what is related to these changes is the refractive power of the two meridians and their slope. It can be seen that the amount of prism that is related to the amount of deviation E _H and _EV does not play any role. This shows that the calculation of the prism amount can be performed by a calculation means that is completely different from the refractive power of the lens to be tested, and means that the calculation process is simplified and the calculation time is shortened.

During actual measurement, in order to measure the refractive characteristics of the lens T to be tested from changes in the slope and pitch of the group of parallel straight lines from equations (1) and (2), the unknowns in equations (1) and (2) must be Z ₁ , Z ₂ ,
Since there are three θ, it can be seen that the solutions to equations (1) and (2) cannot be obtained by changing only one group of parallel straight lines. Therefore, in reality, it is necessary to know the changes in the slope and pitch of the two parallel straight line groups together with one other parallel straight line group. This configuration is shown in FIG. The mask MA in Fig. 2 has a slope m ₁ and a pitch P ₁ of 2
An aperture pattern is formed consisting of a book parallel straight line group L ₁ and two parallel straight line groups L ₂ with an inclination m ₂ and a pitch P ₂ . On D, two projected parallel straight lines L' ₁ with slope m' ₁ and pitch P' ₁ and ₂ with slope m' 2 and pitch P' ₂
The projection of the book forms a group of parallel straight lines L′ ₂ . Since two sets of equations (1) and (2) are obtained from these two sets of projected parallel line groups, a total of four equations, the unknowns θ, Z ₁ ,
Z ₂ can be found. If solving the quadratic equations (1) and (2) to obtain Z ₁ , Z ₂ , and θ is complicated in terms of arithmetic processing, increasing the cost of the processing mechanism and increasing the processing time, the following intermediate All you have to do is apply arithmetic processing.

FIG. 3a shows pattern openings L ₁ and L ₂ formed in the mask MA of FIG. 2. FIG. The slope of L ₁ is m ₁
The pitch is P ₁ , the slope of L ₂ is m ₂ , and the pitch is P ₂ as in Fig. 2. Now, parallel straight line group
Distance from one of L ₁ L ₁₁ to pitch P ₁ times e
Parallel line extending to eP ₁ and parallel line QW with distance fP ₁
think of.

Also, the distance from one line L ₂₁ of the group of parallel straight lines L ₂
Consider a parallel line with gP ₂ and a parallel line UQ with distance nP ₂ . A virtual parallelogram UVWQ is formed from these parallel lines, , and the virtual coordinates of the x-y coordinate system of these four vertices are defined as U ( ₀ x ₁ , ₀ y ₁ ), V
( ₀ x ₂ , ₀ y ₂ ), W ( ₀ x ₃ , ₀ y ₃ ), and Q ( ₀ x ₄ , ₀ y ₄ ).

FIG. 3b is a diagram showing the parallel straight line groups L _{1 ′} , L _{2 ′} projected on the detection plane by the light beams that have passed through the parallel straight line groups L ₁ , L ₂ , which are the aperture pattern of FIG _{. 3a} . As in FIG. 2, L ₂ ' changes to slope m ₁ ' and pitch P _{1 '} , and L 2 ' changes to slope m ₂ ' and pitch P 2 '. This projected group of parallel straight lines is the origin of the x′−y′ coordinates.
Assuming that detection is performed by linear sensors S ₁ and S ₂ that intersect at an intersection angle γ and have an origin O'' at a point translated by ξ in the x'-axis direction and η in the y'-axis direction from O'.
Linear sensor S ₁ detects a group of projected parallel straight lines at detection points A, B, H, and D, and linear sensor S ₂ detects a group of projected parallel straight lines at detection points E, H, G, and H. Then, from the detection points B and F, one of the parallel straight lines projected
Calculate the equation of this L ₁₁ ′ and also calculate from the detection points C and T.
Compute the equation of L ₂₁ ′. Similarly, detection point A,
Another one of the group of parallel straight lines projected from E
The equations of L ₂₂ ′ can be calculated from the detection points N and J of L ₁₂ ′, and the pitch P ₁ ′ of L ₁₁ ′ and L ₁₂ ′ can also be calculated from the detection points N and J of L ₁₂ ′.
The pitch P ₂ ′ of L ₂₂ ′ can also be calculated. Then, from L ₁₁ ′, the pitch P ₁ ′ can be multiplied by the same magnification e as that in Fig. 3a, and we can consider the parallel line ′′ of the pitch of eP ₁ ′, and similarly, the parallel line ′′ of the pitch fP ₁ ′ of,
From L ₂₁ ′, we can consider gP ₂ ′parallel lines with pitch′′ as hP ₂ ′parallel lines with pitch′′, and these parallel lines
Virtual parallelogram from U′V′, ′′, ′′, ′′
We can obtain U′V′W′Q′. The virtual coordinates of the four vertices of this virtual parallelogram in the x-y coordinate system are U' (x ₁ , y ₁ ), V' (x ₂ , y ₂ ), W' (x ₃ , y ₃ ),
If Q′ (x ₄ , y ₄ ), then the virtual parallelogram UVWQ in Figure 3a and the virtual parallelogram in Figure 3b
U′V′W′Q′ corresponds, and this change is precisely related to the refractive properties of the lens to be tested.

Now, the following coefficients and equations are defined for the four virtual points.

A _ij = ( ₀ x _i − x _i ) − ( ₀ x _j − x _j ) A _ik = ( ₀ x _i − x _i ) − ( ₀ x _k − x _k ) B _ij = ( ₀ y _i − y _i ) − ( ₀ y _j − y _j ) B _ik = ( ₀ y _i − _{y i} ) − ( ₀ y _k − y _k ) C _ij = ₀ x _i − ₀ x _j C _ik = ₀ x _i − ₀ x _k D _ij = ₀ y _i − ₀ y _j D _ik = ₀ y _i − ₀ y _k Equation (3a) Here, i, j, and k are assumed to be j or k with i as a reference. From the four virtual points, 12 combinations are possible.

Using the above equation (3a), Z ₁ and Z ₂ regarding the refractive powers of the two principal meridians can be expressed by the following quadratic equation.

(C _ik D _ij −C _ij D _ik )(d/z) ² +(A _ij D _ik +B _ik C _ij −A _ik D _ij −B _ij C _ik )(d/z)+(A _ik B _ij − A _ij B
_ik )=0...Equation (3b) Here, the Katsuko equation for the above coefficient is defined as follows.

[p, q]≡p _ij q _ik −q _ij p _ik [p, q]=−[q, p] Here, if p and q are each A, B, C, or D, Equation (3b) is [C, D] (d/z) ² + {[B, C] - [A, D]} (d/z) + [A, B] = 0... (3c)
Expressed as an expression.

d is the test lens T and mask as shown in Figure 2.
The distance between MAs, z, is the distance between the mask MA and its focal line.

Therefore, as shown in Figure 2, two sets of projected parallel straight lines
Detect the pitches P ₁ ′, _{P 2} ′ and slopes m ₁ ′, m 2 ′ of L ₁ ′, L ₂ ′, create a virtual projection quadrilateral as shown in Figure 3b, and form the parallelogram. By solving the quadratic equation of equation (3) from the vertex, the two roots z ₁ and z ₂ can be found. From these two roots z ₁ , z ₂ , the refractive powers D 1 , D ₂ of the first principal meridian R ₁ and second principal meridian R ₂ of the tested lens T _are obtained.
are respectively D ₁ =1/z ₁ /△d/z ₁ −1 D ₂ =1/z ₂ /△d/z ₂ −
1...(4) It can be obtained as follows.

Also, the angle of the cylinder axis (first principal meridian R ₁ in Figure 1)
The angle θ that it makes with the x-axis has a relationship of =θ+90°. ) is =1/2tan ^-1 {[B,D]-[A,C]/[A,
D]+[B,C]}+90°...(5)

In Figures 3a and 3b described above, pitches P ₁ , P ₂ , P ₁ ' and
P ₂ ′ is multiplied by arbitrary magnifications e, f, g, and h, respectively, but in reality, e=1 and g=1, and the virtual parallelograms U ₀ V ₀ W ₀ Q and U ₀ ′V ₀ ′W The process can be simplified by using _0′Q .

Also, the coordinates of each vertex of the virtual parallelogram are x ₀ −y ₀
The explanation has been made using the orthogonal coordinate system and x-y orthogonal coordinate system, but if we consider the oblique coordinate system x'-y' coordinate system along with the arrangement of linear sensors S ₁ and S ₂ , As shown in Figure 4, the coordinate transformation between the and The origin O ₂ of the '-y' coordinate system is shifted by ξ in the x-axis direction and η in the y-axis direction from the origin O ₁ of the x-y coordinate system. In this case, the coordinate transformation from the x'-y' coordinate system to the x-y coordinate system is x = x'sinα + y'sinβ + ξ y = y'cosβ - x'cosα + η ... (6) From the above equation (3), A _ij = ( ₀ x _i −x _i )−( ₀ x _j −x _j ) Substituting equation (6) into this, A _ij = {( ₀ x′ _i sinα+ ₀ y′ _i sinβ+ξ)−(x′ _i sinα
+
y′sinβ+ξ)}−{( ₀ x′ _y sinα+ ₀ y′ _j sinβ+ξ)
−
(x′ _j sinα−y′ _j sinβ+ξ)} = sinα{ ₀ x′ _i −x′ _i )−( ₀ x′ _j −x′ _j )}+sinβ
{ ₀ y′ _i −
y′ _i )−( ₀ y′ _j −y′ _j )} =A′ _ij sinα＋B′ _ij sinβ …(7a) Also, B _ij =( ₀ y _i −y _i )−( ₀ y _j −y _i ) Using the same calculation as above, B _ij = cosβ { ₀ y′ _i −y′ _i )−( ₀ y′ _j −y′ _j )}−cos
α{( ₀ x′ _i −
x′ _i )−( ₀ x′ _j −x′ _j )} =B′ _ij cosβ−A′ _ij cosα …(7b) Similarly, C _ij C′ _ij sinα＋D′ _ij sinβ …(7c) D _ij =D ′ _ij cosβ−C′ _ij cosα …(7d).

Here, [C, D], [B, C], [A, D], [A,
B], from equations (7a) to (7d), [C, D]=C _ij D _ik −D _ij C _ik = (C′ _ij sinα+D′ _ij sinβ)D′ _ik cosβ−C′ _ik cos
α)−
(D′ _ij cosβ−C′ _ij cosα) (C′ _ik sinα＋D′ _ik sinβ
) = (sin α sin β + cos α + sin β) [C', D'] Similarly, [B, C] = (sin α sin β + sin β cos α) [A', B'] [A, D] = sin α cos β [A', D'] - sin α cos α [A
′、
C′]+sinβcosβ[B′,D′]−sinβcosα[B′,C
′] [A, B] = (sin α cos β + cos α sin β) [A’, B’] Also, [B, C] - [A, D] = (sin α cos β + cos α sin β)
{{B′, C′] − [A′, D′]} Therefore, equation (3c) is sin (α + β) × {[C′, D′] (d/z) ² + [B′, C′ ] − [A′, D′]) (d/z) + [A′, B′]}=0 …(8), and the inside { } is a quadratic equation with the same form as equation (3c), and this From this, it can be seen that the quadratic equation in equation (3c) is an invariant equation that is independent of how the coordinate system is taken. This shows that the degree of freedom in the arrangement of the two linear sensors as detectors is very large. In other words, it is not necessary to place the two linear sensors on the x-y coordinate system and the orthogonal coordinate axes, but it is also possible to place the two linear sensors on the x'-y' coordinate system, and the orthogonal accuracy and optical axis alignment of the linear sensors are Without much thought, it can be made independent of measurement accuracy. During measurement, the parallel straight line group patterns L ₁ and L ₂ with no test lens inserted into the measurement optical system are plotted in the oblique coordinate system x′−
Linear sensors S ₁ arranged on the x′ axis and y′ axis of the y′ coordinate,
Detected in step S ₂ , the virtual parallelograms U, V, W, and Q created from this detection are used as reference virtual parallelograms, and then the lens to be measured is inserted into the measurement optical system. Projected virtual parallelogram U′,
V', W', and Q' are created, and the refractive characteristics of the lens to be tested are determined from the reference virtual parallelogram and the projected virtual parallelogram. In this case, the coordinate system of the biparallelogram is considered only for the oblique coordinate system x'-y', which can be arbitrarily selected, and this oblique coordinate system x'-y' is As mentioned above, the selection is an invariant equation that is unrelated to the quadratic equation for calculating the internal refractive power of the refractive characteristic calculation of the test lens.
The present invention has the very advantageous effect that no adjustment is required for the arrangement of the linear sensors S ₁ and S ₂ in terms of assembly or maintenance.

The cylindrical axis direction of the lens to be tested is given by equation (5). Equation (5) is an equation for the orthogonal coordinate system, but if the sensor is located in the oblique coordinate system It can be calculated as a cylindrical axis when used.

θ=1/2tan ^-1 X{cos2β[B′,D′]−cos(α−β)
′] + [B′, C′] + cos2α/sin2α [B′, D′] + si
n (α − β) ([A′, D′] + [B′, C′]) − sin2α [A′, C′] / [A′, C′]} …(9) The cylinder axis is the above ( From θ in 12), it can be determined as =θ+90°.

Next, the principle of measuring prism refractive power will be explained based on FIG. 5.

x ₀ − _{y 0} , the calculation of the prism value using the x-y orthogonal coordinate system is based on the group of parallel straight lines L ₁ of pitch P ₁ and the parallel straight lines of pitch P ₂ , which are arranged symmetrically at the same angle γ with respect to the y ₀ axis. One straight line each of group L ₂ L ₁₁ , L ₂₁
Similarly, draw the straight line at e′P ₁ from f′P ₁ , g′P ₂ , and n′P ₂ , and the _four vertices of the virtual parallelogram _are Take it to match. That is, if a virtual parallelogram is made symmetrically with respect to the measurement optical axis O, the center of this virtual parallelogram will coincide with the measurement optical axis O.
Next, measure the lens to be tested and calculate the projected parallel straight line group.
Detect L′ ₁ and L′ ₂ and draw straight lines ′ and ′ at e′P′ ₁ from the projected parallel line L′ ₁₁ . Similarly, a straight line with f′P′ ₁
Subtract ′′ at W′′, gp′ ₂ and ′′ at h′P′ ₂ to create a virtual parallelogram ′′′′. The four vertices of this virtual parallelogram are ′(x ₁ , y ₁ ) in the x-y coordinate system,
V′ (x ₂ , y ₂ ), ′ (x ₃ , y ₃ ), ′ (x ₄ , y ₄ ), and from the coordinates of these four vertices, the horizontal prism amount P _H ,
and the vertical prism amount P _V is expressed by the following equation.

Here, d is the distance between the test lens and the mask surface.

_{When measuring in the oblique coordinate system 2} ) ( ₀ x ₃ , ₀ y ₃ ), ( ₀ x ₄ , _0
y4 )
Set the virtual point to satisfy { ₀ x ₁ + ₀ x ₂ + ₀ x ₃ + ₀ x ₄ = 0 ₀ y ₁ + ₀ y ₂ + ₀ y ₃ + ₀ y ₄ = 0...(12) Bye. And horizontal prism P _H , vertical prism P _V
are given by equation (10), so if we transform equation (12) using equation (6), we get So, if we convert equation (10) using equation (6) in the same way, we get becomes. Coordinates ( ₀ x′ _i , ₀ y′ _i ) of the initial virtual point ( ₀ x _i , ₀ y _i ) in the oblique coordinate system when the test lens is not inserted and when the test lens is inserted into the measurement system Since this is the difference between the measurement coordinates of and the coordinates (x′ _i , y′ _i ) in the oblique coordinate system, the following equation can be obtained from equations (13) and (14).

This formula represents the prism value.

As described above, in the present invention, the refractive power of the tested lens can be calculated using an invariant equation that is independent of the coordinate system, but oblique-orthogonal coordinate transformation is required for the cylinder axis and prism value. (12), (15)
It is necessary to convert the formula, but if the calculation mechanism is complicated, the sixth
After performing orthogonal coordinate transformation using the equation, the astigmatism axis and prism value may be calculated using the calculation equations (5) and (10) using the orthogonal coordinate system.

In this way, in the present invention, the group of parallel straight lines on the mask is measured without inserting the test lens into the measurement optical system.
If a symmetrical virtual parallelogram is created from L ₁ and L ₂ with respect to the optical axis O, then the lens to be tested is inserted into the measurement optical system, and a similar projected virtual parallelogram is created from the projected parallel straight line image. By creating this, the amount of prism can be calculated, and this means that the amount of prism can be measured independently without knowing anything about the refractive power of the first and second principal meridians of the lens to be tested or its inclination angle. This is very advantageous considering that with conventional lensmeters, the prism value could only be calculated by knowing the refractive characteristics of the lens to be measured. Since the step of calculating the refractive characteristic of the detection lens and the step of calculating the prism value can be performed independently and in parallel, the calculation time can be significantly reduced.

Further, the present invention is not limited to so-called lensmeters for measuring eyeglass lenses, but can be applied to a wide range of devices for measuring optical characteristics of optical systems.

Also, when creating a virtual parallelogram, a straight line
A virtual parallelogram was created by multiplying the pitch of the straight line group to which these straight lines belong to L ₁₁ and L ₂₁ by n and drawing a virtual straight line parallel to the slope of the straight lines L ₁₁ and L ₂₁ .
The method of creating a virtual parallelogram is not limited to this, but as shown in Fig. 3c, a virtual straight line _l11 having an angle β with respect to the straight line _L11 is created, and a straight line _L21
Create a virtual straight line l ₂₁ with an angle α to
It goes without saying that virtual parallelograms u, v, w, and q may be created based on the virtual straight lines l ₁₁ and l ₂₁ created by the rollers, but this changes the measurement principle of the present application. isn't it.

A specific example of an optical lens refraction measuring apparatus based on the measurement principle described above will be described in detail below with reference to the drawings.

FIG. 6 is a diagram showing the optical system arrangement of the device according to the invention. In the figure, 2a and 2b are light sources, such as LEDs, which are alternately driven by the drive circuit 1 and have different emission wavelengths.

The light beam emitted from the light source 2a is reflected by the wavelength-selective reflective-transmissive film 3a of the dichroic prism 3 and enters the relay lens 4. On the other hand, the light beam emitted from the light source 2b passes through the reflective/transmissive film 3a of the dichroic prism 3 and enters the relay lens 4. The light beam incident on the relay lens 4 is focused on a pinhole 5 by the relay lens 4. This pinhole 5 indicates the apparent size of the light source, the amount of light at the time of measurement,
It is made to have an appropriate size in consideration of diffraction phenomena, and a diameter of about 0.1 to 0.3 mm is used. The light beam emitted from the pinhole 5 is made into a parallel light beam by a collimator lens 6, is bent downward by a reflection mirror 7, and enters a test lens 8 held by a holding means (not shown). The light beam exiting the test lens 8 has its optical path bent by the reflecting mirror 9 and then enters the relay lens 10 . relay lens 1
The light beam emitted from 0 passes through the dichroic prism 11
The wavelength-selective reflective-transmissive film 11a reflects or transmits the incident light beam depending on its wavelength. For example, the transmitted light flux is then reflected by a reflection mirror 12 and then reflected by a light flux limiting mask 13.
b, and after the information necessary to detect the optical characteristics of the test lens 8 is selected, the semi-transparent film 1
4a, a part of the light beam is reflected by the semi-transparent film 14a, enters the line sensor 15, and is detected. The other part passes through the semi-transparent film 14a to the line sensor 1.
6 and is detected. On the other hand, the light flux reflected by the reflective/transmissive film 11a of the dichroic prism 11 has its optical path bent by the reflection mirror 17 and then enters the light flux limiting mask 13a, where it is necessary to detect the optical characteristics of the lens 8 to be tested. After the information is selected, it enters the half mirror 14, and a part of the incident light beam is reflected by the semi-transparent film 14a and passes through the line sensor 1.
6 and is detected, and the other part is detected by the semi-transparent film 14a.
The light passes through the line sensor 15 and is detected. Note that in this embodiment, the luminous flux limiting mask 1
3a and 13b are distances △ from the test lens 8, respectively.
It is placed at a position conjugate to MA by the relay lens 10 so as to have the same effect as if it were placed at a position MA separated by distance d. Similarly, each of the line sensors 15 and 16 is also arranged by the relay lens 10 at a position conjugate with the position of the detection surface D. Furthermore, as the line sensors 15 and 16 of this embodiment, linear CCD solid-state image sensors or the like are used.

These two line sensors 15 and 16 are arranged so as to intersect with each other within the conjugate plane D thereof.

In this embodiment, the light flux emitted from the light source 2a is as follows: dichroic prism 3 → relay lens 4 → pinhole 5 → collimator lens 6 → reflection mirror 7 → test lens 8 → reflection mirror 9 → relay lens 10 → dichroic mirror 11 → Reflection mirror 1
7→mask 13a→half mirror 14→line sensor 15 and line sensor 16 to form a first measurement optical path. On the other hand, the light beam emitted from the light source 2b goes through the dichroic prism 3 → relay lens 4 → pinhole 5 → collimator lens 6 → reflection mirror 7 → test lens 8 → reflection mirror 9 → relay lens 10 → dichroic prism 11 → reflection mirror 12→mask 13b→half mirror 14→line sensor 15 and line sensor 16 to form a second measurement optical path.

FIGS. 7a and 7b are diagrams showing mask patterns of the aforementioned light flux limiting masks 13a and 13b, respectively.

The mask 13a has a parallel straight line group 20 consisting of a plurality of straight line patterns with a slope _m2 and a pitch p. Furthermore, at least one of the parallel straight line groups 20 has a reference straight line pattern 22 having a different thickness so as to be distinguishable from other straight line patterns. Similarly, the mask 13b has a reference straight line pattern 23 with a slope m ₁ ,
It has a group of parallel straight lines 21 with pitch p.

Here, in this embodiment, the reference straight line pattern 22,
No. 23 was distinguished from other straight line patterns by having a difference in thickness, but the present invention is not limited to this, and it may also be distinguished by having a difference in light transmittance or transmission wavelength characteristics. Alternatively, all straight lines may be the same, and the pitch at a specific location may be changed to serve as a reference straight line.

Parallel straight lines 20 and 21 of the masks 13a and 13b intersect with each other at an angle θ on the common conjugate plane MA of the masks 13a and 13b formed by the relay lens 10 in FIG. 6, and there is a bisector 24 thereof. It is configured such that the angle at which it intersects with the reference axis 25 is ε. In this embodiment, θ=90° and ε=90°.

Note that the pitches of the groups of parallel straight lines 20 and 21 are selected to be the same value P, which is different from the mask 13.
This is only to facilitate the production of a and 13b.
Groups of parallel straight lines with different pitches may be used, and the pitches of the straight line patterns in one group of parallel straight lines do not need to be the same.

Further, the angles θ and ε can also be arbitrarily selected. FIG. 8 is a diagram showing the projection relationship of the mask pattern image onto the line sensor when the line sensor detects the mask pattern image. As shown in FIG. 8, the line sensors 15 and 16 shown in FIG. 6 are arranged by means of a relay lens 10 such that they have a crossing angle γ on a common conjugate plane, that is, a detection plane D. And this line sensor 15, 16
With the lens 8 to be tested above, the light beam having the refractive characteristic information passes through masks 13a, 13b, and the parallel straight line group 20 of the mask 13a forms straight line pattern images 20'a, 20'b, . . . on the line sensor. ...22'...
20'h. Similarly, mask 13b
The parallel straight line group 21 is a straight line pattern image 21'a, 2
1'b...23'...21'i.
These straight line pattern images are projected onto the test lens 8.
Due to the refractive properties of , the pitches are changed to p' and p'', their intersection angle to each other is changed to θ', and the angle at which their bisector 24' intersects the reference axis 25' is changed to ε'.

During measurement, first, the first light is emitted by the light source 2a.
A measurement optical path is formed, and linear pattern images 20'a, 20'b...22'...20'h are formed by the mask 13a.
is projected onto the line sensors 15 and 16. Here, the linear pattern images 20'a, 20'b...20'h are detected by the line sensor 15, respectively.
e ₁₁ , e ₁₂ ...detected as e ₁₇ . Similarly, the line sensor 16 detects the detection points f ₁₁ , f ₁₂ , . . . f ₁₉ .

Next, when the light source 2b is made to emit light, a second measurement optical path is formed, and linear pattern images 21'a, 21'b...23'...21'i are projected onto the line sensors 15 and 16 by the mask 13b. be done. Here, the line sensor 15 detects straight line pattern images 21'a,
21'b...23'...21'i are the respective detection points
e ₂₁ , e ₂₂ ...detected as e ₂₉ , e ₂₀ . Similarly, the detection points f ₂₁ and f ₂₂ are detected by the line sensor 16.
...Detected as f ₂₆ .

FIGS. 9A to 9M are timing charts showing line sensor outputs and subsequent calculations when the line sensor detects a linear pattern image. A is a pulse train for reading and driving the detection output of the line sensor, and when this pulse is input to the line sensor, the detection output is sequentially output from the line sensor. B is a straight line pattern 20'a, 20'b...22'...20'h on the line sensor 15.
It shows the detection output waveform (envelope) from the line sensor 15 when projected. The output waveform of B has output level rises corresponding to the detection points e ₁₁ , e ₁₂ . . . e ₁₇ . Similarly, C is the detection output waveform of the linear image patterns 20'a, 20'b...20'h by the line sensor 16,
D is a straight line pattern 21' obtained by the line sensor 15.
a, 21'b...23'...21'i, and E is the detected output waveform of the linear image patterns 21'a, 21'b...23'...21'i by the line sensor 16. . F to I are the detection output waveforms B described above.
This is a rectangular wave output waveform obtained by shaping ~E into a rectangular wave using a Schmitt trigger circuit, and the output waveform F~I
correspond to output waveforms B to E, respectively. Next, the center position of each rectangular wave of the obtained rectangular wave output waveforms F to I is determined, and this center position is positioned using the sensor element number of the line sensor as a scale.

That is, as shown in FIG. 10, E ₁ , E ₂ ,...
... _{E N- 1 , E}
E ₁ to E _1+n sensor elements produce square wave output e _B
When is being output, the width △ _A of the rectangular wave output e _A corresponds to the number of sensor elements n, and the width △ _B of the rectangular wave output e _B corresponds to the number m of sensor elements, so the rectangular wave output e _A The center position O1 is n/2 from the E _pth element
It can be seen that each E _p +n/2=E _c corresponds to the 1st element. Similarly, the center position O ₂ of the rectangular wave output e _B corresponds to E _1+n/2 = E _c second element. or,
In order to further increase detection accuracy, interpolation between sensor element pitches is required, but this is done by accurately detecting the envelope of the rising and falling edges of the output signal and then shaping the waveform at an appropriate slice level. This is achieved by detecting the center position using a clock pulse that has a sufficiently higher frequency than the pulse train that drives the center position.

In this way, the position of the linear pattern image can be obtained by determining the center position of the rectangular wave output waveform of the line sensor obtained from the detection point and by positioning it by the element number of the line sensor, that is, as a coordinate value with the line sensor as the coordinate axis.

FIGS. 9 J to M are diagrams showing each detection point as a coordinate value on the line sensor using the above method,
The coordinate values e′ ₁₁ , e′ ₁₂ ...e′ ₁₇ are the detection points e ₁₁ , e ₁₂ , ...
e ₁₇ respectively. Also, the following coordinate value f′ ₁₁
~f' ₁₉ is the detection point f ₁₁ ~ _{f 19} , the coordinate value e' ₂₁ ~ e' ₂₀ is the detection point e ₂₁ ~ e ₂₀ , and the coordinate value f' ₂₁ ~ f' ₂₆ is the detection point f ₂₁ ~ f ₂₆ corresponds to each.

Furthermore, as shown in FIG. 10, the number m of sensor elements that output the rectangular wave output e _B is different from the number n of sensor elements that output the other rectangular wave output e _A , and m>n
Therefore, it can be seen that this rectangular wave output e _B is the detection output of a straight line pattern image based on the reference straight line pattern as shown in FIGS. 7a and 7b. In this embodiment, the detection points e ₁₅ ,
e ₁₆ , e ₂₅ , and f ₂₃ are the reference straight pattern image 2, respectively.
2′, 23, is the detection point where e′ ₁₅ , f′ ₁₆ ,
It can be seen that e′ ₂₅ and f′ ₂₃ are the respective reference coordinate values.

Then, the equation of the reference straight line pattern image 22' can be determined from the reference coordinate values e' ₁₅ and f' ₁₆ , and the reference coordinate value
The equation of the reference straight line pattern image 23' can be determined from e' ₂₅ and f' ₂₃ . Also, the reference coordinate values e′ ₁₅ , f′ ₁₆ , e′ ₂₅ ,
Equations for other linear pattern images can be determined from each coordinate value ordered with f′ ₂₃ as a reference. For example, the next coordinate value e′ ₁₆ after the reference coordinate value e′ ₁₅ and the reference coordinate value f′ ₁₆
The equation of the linear pattern image 20'f can be determined from the next coordinate value _f'17 . In this way, the equations of many straight line pattern images can be determined from each coordinate value, and since these straight line pattern images belong to the same parallel straight line group, their parallelism will not be broken, so these many straight line equations can be averaged. By becoming
More accurate and precise detection results can be obtained. Furthermore, it is possible to obtain a large number of values for the pitch P' of each of the large number of equations obtained, and by averaging these values, it is possible to obtain a precise pitch P'. This is a major feature of the present invention.

Next, while referring to Figures 11 to 13,
A virtual straight line is generated from the equation of the straight line pattern image detected by the line sensor, and based on this straight line, any four lines are drawn on the same plane as the straight line pattern image projection plane.
A method of determining the points and measuring the refractive characteristics of the lens to be tested from changes in these four points will be described. FIG. 11 shows a straight line pattern 20 on the line sensors 15, 16 when the test lens 8 is not inserted into the measurement optical path.
21 is projected. At this time, straight line pattern images 20'' (in FIG. 11, reference straight line pattern images 22'', 23'' and straight line patterns 20''e,
Although only 20''f, 21''d, and 21''e are selected and illustrated) and 21'', their straight line equations and pitches P are determined by the method described above. Then, for example, using the straight line pattern image 20''e as a reference,
An imaginary straight line 30 with an inclination of fxm ₂ at a position exP apart
It is also possible to generate a virtual straight line 31 with an inclination fxm ₂ at a position separated by gxP on the opposite side. Using a similar method, for example, with the straight line pattern image 21''d as a reference, a straight line 32 with an inclination of fxm ₁ can be generated at a position separated by hxP, and a straight line 33 with an inclination of fxm ₁ can be generated at a position separated by ixP. Here, the coefficient e, f, g, h, and i are coefficients that can be selected arbitrarily, and usually generate a virtual straight line with the same slope as f=1, that is, the slopes m ₁ and m ₂ of the linear pattern image equation. , g, h, and i are selected so that the intersection points 36, 37, 38, and 39 of the generated virtual straight lines are symmetrical with respect to the center 24 of the mask. As already stated in the principle explanation, generating a virtual straight line in this way facilitates calculation of the prism refractive power of the lens to be tested.

Next, the first method is to insert a test lens into the measurement optical path, use a line sensor to detect a straight line pattern image created by a light flux changed by the refractive characteristics of the test lens, and to obtain a virtual straight line from this straight line pattern.
Shown in Figure 2.

First, due to the refractive characteristics of the lens being tested, the pitch
As described above, the linear pattern images 20' and 21' whose slopes have been changed to P'P'' and slopes m ₁ ' and m ₂ ', respectively, are detected and the equations thereof are calculated.
The eleventh
A virtual straight line 3 at the position exP'' with the same amount of coefficient e as used to generate the virtual straight line 30 in the figure.
Generates 0'. Note that the slope of this imaginary straight line 30' is, since the coefficient f of the slope fxm ₂ of the imaginary straight line 30' is set to f=1 in Fig. 11, the slope of the imaginary straight line 30' is
Similarly, the coefficient f of fxm ₂ ' is set to f=1. In the same way, using the straight line pattern image 20'e as a reference,
A virtual straight line 31' is placed at the position gxP'', and a virtual straight line 31' is placed at the position hxP' with the straight line pattern image 21'd as a reference.
2' and a virtual straight line 33' are generated at the position of ixP'. And these virtual straight lines 30', 31',
From 32', 33' to intersections 36', 37', 38', 3
9' can be obtained, and from these four intersection points its center 3
4' can be obtained.

In this way, the four points sought were 36-39.
are displaced at four points 36' to 39' on the detection surface D depending on the refractive characteristics of the lens to be tested. 1 shows this situation.
Figure 3. Then, based on this amount of displacement, the above
The refractive characteristics of the lens to be tested can be calculated using equations (3) to (5). As in this example, the four intersections of virtual straight lines when the test lens is not inserted into the measurement optical path are used as reference points, and the displacement amount of the four intersections when the test lens is inserted into the measurement optical path is determined. When used, the above-mentioned third equation becomes completely unchanged with respect to the coordinate system created by the two line sensors, so there is a great advantage that there is no need to manage the intersecting angle and intersecting position of the line sensors at the time of assembly.

FIG. 14 is a simple block diagram showing an example of a processing circuit for performing the above-mentioned arithmetic processing. Line sensor driver 100, 101
As shown in FIGS. 9B to 9C, the line sensors 15 and 16 driven by the drive circuit 1
Detection output signals based on the linear aperture pattern projected image of the light flux limiting mask 13a are sent to the signal lines 102 and 103 by the light emission of the light source 2a driven by the light flux limiting mask 13a. 104 is an analog switch, which is controlled by a microprocessor 105. The microprocessor 105 is the line sensor 1
When the line sensor scan start pulse 106 is interrupted by the driver 100 driving the line sensor 15, the analog switch is controlled so that the output of the line sensor 15 is input to the A/D converter 107. The A/D converter 107 converts the output of each element of the line sensor read out by the line sensor readout pulse 108 as shown in FIG. 9A from the driver circuit 100 from analog to digital, and converts the converted digital value. Supplies the microprocessor. Here, the A/D converter 107 has 8
A sensor having a resolution of about 1/256 bit (1/256) and a conversion time faster than the scanning frequency of the line sensor is selected. The microprocessor 105 is
A data memory 10 that reads the output of the line sensor 15, which is converted into a digital value for each element, is composed of a RAM (random access memory), etc.
9 is stored sequentially. Therefore, data memory 10
9, the outputs from the first element of the line sensor are stored as dental values in order from a predetermined position (address). For example, if the line sensor has 1728 elements, once the 1728 data have been captured, the microprocessor 10
5 stops further data acquisition and waits to be interrupted by the scan start pulse 110 that drives the line sensor 16. When an interrupt is received, the analog switch 104 is controlled and the output of the line sensor 16 read by the line sensor read pulse 111 is converted into a digital value and stored in the data memory 1.
Continuing to store in 09. Next, the microprocessor 105 controls the drive circuit 1 to turn off the light source 2a that has been emitting light and causes the light source 2b to emit light. Then, by driving in the same manner as described above, FIG. 9d,
Data memory 1 uses the detection output of e as a digital value.
Store in 09. All measurement data is now stored in the data memory 109. Thereafter, the arithmetic circuit 112 in the microprocessor 105 performs the following processing based on the data written in the data memory 109.

(1) Detecting which element of the line sensor the center position of the line sensor output waveform generated by the projected image of the linear aperture pattern of the light flux limiting mask is located.

(2) In the coordinate system created by the two line sensors,
Find the equation for each linear aperture pattern image.

(3) 30' in Figure 12 by the method already described.
Generate the equation of a virtual straight line such as ~33',
As their intersection points, the four points 3 shown in Figure 13 are
The coordinate positions of 6' to 39' are determined, and then the center position 34' is determined.

(4) In advance, set the four reference positions 36 to 39 and their center 34 when no test lens is inserted.
The coordinate position of and each point 36' found in the previous section (3)
From the coordinate positions of 39' and 34', calculate according to equations (3) to (5) above to determine the spherical power S, cylindrical power C, astigmatic axis direction Ax, and prism refractive power of the test lens.
Find Px and Py.

Each value obtained through the above processing is output to the display 113 and printer device 114 shown in FIG. 14. All of the above processing is performed according to the program recorded in the program memory 115. It is not unusual for a microprocessor to perform the above processing, and can be easily accomplished by those skilled in the relevant technical field.

The present invention is not limited to the embodiments described above, but includes various modifications. A few examples are disclosed below.

In the first embodiment shown in FIG. 6, two light sources with different emission wavelengths and a dichroic prism that selectively reflects or transmits the light from these two light sources are used to form two measurement optical paths. However, instead of using two light sources, a mechanical chopper may be used to select the measurement optical path as shown in FIG. In FIG. 16, the same or equivalent components as in the first embodiment shown in FIG. 6 are given the same reference numerals and explanations are omitted. The relay lens 10 divides the light beam from the relay lens 10 into two light beams. half mirror 1
A first chopper 153a is disposed on a first measuring optical path 152 that the light beam that has passed through the semi-transparent mirror surface 151 of 50 follows. On the other hand, a second chopper 153b is arranged in a second measuring optical path 154, which is followed by the light beam reflected by the semi-transparent mirror surface 151 of the half mirror 150. These first and second choppers are each connected to a chopper drive circuit 155,
subject to this control. First, when the first chopper 153a is inserted into the first measurement optical path 152, the second chopper 153b is moved out of the second measurement optical path 154, and the light flux passing through the second measurement optical path is incident only on the mask 13a. Let this mask 13
The light beam that passed through a is divided into 2 by the half mirror 14.
and projected onto line sensors 15 and 16, respectively.

Next, the chopper drive circuit removes the first chopper 153a from the first measurement optical path and inserts the second chopper 153b into the second measurement optical path 154, thereby blocking the light beam proceeding to the second measurement optical path. Then, only the light beam traveling along the first measurement optical path is passed through the mask 13.
The light flux that was incident on b and passed through the mask 13b is
The image is divided into two by a half mirror 14 and projected onto line sensors 15 and 16, respectively.

FIG. 16 shows another embodiment regarding the arrangement of line sensors. In the first embodiment shown in FIG. 6, the licensors 15 and 16 are arranged so as to cross each other on the optically conjugate detection surface D of the relay lens 10, but the present invention is not limited to this. Further, the intersection may be arranged so that the extension lines of the line sensors virtually intersect. Furthermore, as can be understood from the principle of the present invention, the present invention provides a linear equation for a projected image of a straight line pattern formed on a light beam splitting mask. The first step in measurement is to determine the Since the equation of a straight line can be determined by measuring at least two points on the straight line, the line sensor for detecting the straight line pattern image can be freely placed as long as it is not parallel to the straight line pattern image. FIG. 16 discloses an example of this, in which two line sensors 160 and 161 are arranged parallel to each other on the detection surface D. More specifically, the line sensor 160 is located within the plane in which the line sensor 15 in FIG.
61 are connected to each other on the detection surface D within the plane in which the line sensor 16 in FIG. 6 is arranged.
It is sufficient to arrange the book line sensors so that they are parallel to each other.

Fig. 17 uses one parallel line sensor instead of the two parallel line sensors described above, and combines this with an optical means for image shifting to essentially create two parallel line sensors. This is an disclosure of an embodiment that has the same effect as the one used. In FIG. 17, the optical arrangement in front of the relay lens 10 has the same optical arrangement as that in FIG. 6, and is not shown. Components that are the same or equivalent to those of the first embodiment shown in FIG. 6 are given the same reference numerals and their explanations will be omitted. In front of one line sensor 162, an image shifting optical means 170 such as a plane parallel is arranged whose rotation axis is perpendicular to the incident optical axis and parallel to the arrangement direction of the sensor elements of the line sensor. There is. The plane parallels 170 are rotated by an angle in the direction of an arrow 173 about the rotating shaft in synchronization with each other by a drive circuit 172.

When the plane parallel 170 is now positioned perpendicular to the incident optical axis 175 as shown by the solid line, the light beam that has now passed through the mask 13a of the second measurement optical path and transmitted through the semi-transparent surface of the half mirror 14 is incident. It is projected onto the line sensor 162 as a projection light beam having a projection optical axis 177 coaxial with the optical axis 175 . Next, by driving the driver circuit 172, the plane parallel 170 is rotated by an angle and moved to the position 170'. is projected onto the line sensor 162 as a projection light beam having the projection optical axis 177' as the projection optical axis. It goes without saying that the same effect is applied to the light beam that has passed through the mask 13b in the first measurement optical path after being reflected by the half mirror 14. Note that the first
If a two-dimensional sensor is used instead of the line sensor shown in FIGS. 6 and 17, the number of detection points can be increased.

In contrast to all of the above-mentioned embodiments in which the measurement optical path is divided into two and a total of two light flux limiters 227 are arranged, one in each measurement optical path, in FIG. This is an example of an optical property measuring device that uses one mask on which two different patterns are formed. Below, in the explanation of this embodiment with reference to FIG. 18,
Components that are the same or equivalent to those in the embodiment are designated by the same reference numerals, and the description thereof will be omitted. The light beam emitted from the relay lens 10 passes through a mask 20 having a wavelength-selective pattern configured as described below.
After passing through 0, the light is divided into two by a half mirror 14 and projected onto line sensors 15 and 16, respectively.

FIGS. 19a to 19f are diagrams illustrating the structure of the mask 200. Straight line patterns 310 and 31
1 is a thin film 3 which has wavelength selection characteristics as shown in Fig. 19e and transmits wavelengths longer than λ ₀ with the wavelength λ ₀ as the boundary.
It is made up of 12. This configuration is shown in FIG. 19b as a sectional view taken along line A-A'. In FIG. 19b, a thin film 312 having the characteristics shown in FIG. 19e is coated on a mask substrate 313 with a gap 314 in between. On the other hand, straight line patterns 315, 31
6 is formed of a thin film 317 having wavelength selection characteristics as shown in FIG. 19f. This thin film 317
transmits wavelengths shorter than wavelength λ ₀ . and thin film 3
17 is also coated on the mask substrate 313 with a gap 314 between them. Thin film 312 and thin film 31
7 is a gap 3 perpendicular to the mask substrate 313.
14, the portion 318 surrounded by the patterns 310, 311, 315, and 316 is coated with two layers of films 312 and 317, and thus becomes a portion that does not transmit light. On the other hand, since the gap 314 is not coated with a glaze, light can pass through the entire area. Note that in order to make the optical path the same as that of the coated surface, a refractive material for optical path adjustment may be inserted into 314.

Note that, as described above, the linear patterns 311 and 316 have different thicknesses and transmittances to distinguish them from the other linear patterns 310 and 315.

In FIG. 18, when the light emitting source 2a having emission wavelength characteristics as shown by the broken line in FIG. The mask 200 and the linear pattern 3 pass through the collimator lens 6, the test lens 8, and the relay lens 10.
The light beam passes through a straight line pattern with direction components indicated by 10 and 311, and this passing light beam is divided into two parts by a half mirror 14 and projected onto line sensors 15 and 16. At this time, as shown in FIG.
The linear pattern images 310', 311' are detected by the line sensor 15, the detection points e ₁₁ , e ₁₂ , e ₁₃ are detected by the line sensor 16, and the detection points f ₁₁ , f ₁₂ ,
f ₁₃ is detected. Next, when the light emission is switched to the light emitting light source 2b having light emitting characteristics as shown by the broken line in FIG. 200 straight line patterns 315, 316
The light beam passes through a straight line pattern with a direction component shown by , and this passing light beam is divided into two parts by a half mirror 14 and projected onto line sensors 15 and 16 . Then, the line sensor 15 detects detection points e ₂₁ , e ₂₂ , and e ₂₃ , and the line sensor 16 detects detection points f ₂₁ , f ₂₂ , and f _{23 ,} respectively.

FIG. 21 shows that many of the embodiments described above have at least two
FIG. 6 is a diagram showing an embodiment in which detection is performed by moving one line sensor within a detection plane, whereas a line sensor fixedly placed on the book is used. Components that are the same or equivalent to those in the above-described implementation are given the same reference numerals, and descriptions thereof will be omitted.

The light beam that has passed through the mask 13b in the first measurement optical path 152 is reflected by the reflective film 211 of the dichroic prism 210, which selectively reflects or transmits wavelengths, and enters the line sensor 212. Here, the line sensor 212 is connected to the sensor rotation angle control circuit 213.
A certain angle is set by the motor 214 in response to a command signal from the motor 214, and the first detection is performed at this set angle. Next, the line sensor is rotated to a different angle and a second detection is performed. Thereafter, detection is similarly performed at a large number of angular positions, and a linear equation of a projected image of the linear pattern of the mask 13b is calculated from these detection results. Next, switch the light source and
The measurement light beam is passed through the mask 13a in the second measurement optical path 154. The light beam passing through the mask 13a passes through the reflective film 212 of the dichroic prism 210, enters the line sensor 212 in the same manner as described above, and is detected in the same manner.

Note that instead of rotating one line sensor, it may be moved in parallel within a plane continuously or in multiple steps. Alternatively, one line sensor may be fixed and a known optical image rotator may be rotated, or a blender may be used. By continuously rotating the parallel beam, the projection light beam may be rotated or translated in parallel or continuously or in multiple steps. In this case, it goes without saying that the image rotator and the Blen parallel should be placed between the mask and the line sensor.

Further, a two-dimensional plane sensor may be used for detection instead of a line sensor. According to this embodiment, more detection points can be detected than in the previously described embodiments, and measurement accuracy can be improved.

FIGS. 22, 23, and 24 are diagrams showing seventh, eighth, and ninth embodiments of the present invention. The straight line pattern groups are arranged in different directions on one mask means, or on one mask means with different wavelength selection characteristics, but instead, only one parallel straight line pattern group is arranged on one mask means. The mask means is formed on the lens to be tested, and the mask means is arranged behind the lens to be tested, so that the light beam passing through the lens to be tested has different arrangement directions of the linear pattern group in at least two places relative to itself. This embodiment is configured so that the light flux passing through the lens to be inspected is incident on the mask means, and has the same effects as the above-mentioned embodiments.

FIG. 22 is a diagram showing an embodiment in which the mask means is rotated with respect to the light beam passing through the lens to be examined.

In FIG. 22, the light beam that has passed through the test lens 8 passes through the relay lens 10 and enters the mask means. Here, the mask means is a mask in which a plurality of parallel linear patterns are arranged in only one direction, such as a mask 13a shown in FIG. 7a, and this mask 13a is arranged in a predetermined arrangement direction. Place it in the optical path so that it looks like this. The light beam passing through this mask 13a is divided into two light beams by a half mirror 14, as in the previous embodiment, and each of the light beams is projected onto line sensors 15 and 16 and detected. Next, the mask 13a is connected to the motor drive controller 21.
After rotating the measuring optical axis O by a predetermined angle by a pulse motor 216 controlled by a pulse motor 216 controlled by the mask 13a, the light flux from the test lens 8 is made to enter the mask 13a again. Detect it with

FIG. 23 shows that the embodiment of FIG. 22 is the test lens 8.
An embodiment in which the masking means is rotated with respect to the light beam that has passed therethrough, whereas the masking means is fixed and the light beam passing through the test lens itself is rotated using the measurement optical axis O as the rotational axis. It is. To do this, the light beam passing through the lens to be inspected may be incident on a light beam rotating means such as a known image rotator 220, and this image rotator may be rotated. The light flux that has passed through the test lens 8 passes through the relay lens 10, is rotated through an image rotator placed at a predetermined angle, and then passes through the fixedly placed mask 13a, and is then subjected to the above-described implementation. It is detected by line sensors 15 and 16 as in the example. Next, the image rotator is rotated by a predetermined angle, and the light beam passing through the test lens is rotated to a different angle than the previous time, and the mask 1 is rotated.
3a and send it to the line sensors 15, 16.
Detect it with

If there is a concern that the mechanism for rotating the mask means or the image rotator is a movable element as in the eighth and ninth embodiments described above, which may lead to a decrease in measurement accuracy, the following 24th embodiment is applicable.
This problem can be solved by configuring the device as in the ninth embodiment shown in the figure. A first relay lens 10c and a second relay lens 10d which cooperate to relay the incident light flux are arranged behind the test lens 8. Between the relay lens 10c and the relay lens 10d are two dichroic prisms 22 that selectively reflect or transmit the incident light depending on its wavelength.
3, 224 and reflecting mirrors 221, 222 are arranged as shown in the figure, and the relay lens 10c, the dichroic prism 223, the reflecting mirror 221,
Dichroic prism 224, relay lens 1
An optical path length correction lens 227 is arranged in this first measurement optical path, which constitutes a first measurement optical path 225 at 0d. A second measurement optical path 226 is composed of the relay lens 10c, the dichroic prism 223, the reflecting mirror 222, the dichroic prism 224, and the relay lens 10d. Reflection mirror 222 and dichroic prism 224 of second measurement optical path 226
An image rotator 220 whose reflective surface 220a is rotated by a predetermined angle about the measurement optical axis O as a rotation axis is fixedly disposed between the two.

First, the light beam emitted from the light source 2b passes through the dichroic prism 3, passes through the test lens 8, and then enters the relay lens 10c. relay lens 10
The light beam emitted from c passes through the prism 223,
The light beam entering the mask 13a through the first optical path 225 and exiting the mask 13a is detected by the line sensors 15 and 16. Next, the light emission is switched to the light source 2a having a different emission wavelength from the light source 2b. The light beam emitted from the light source 2a is reflected by the prism 3 and enters the lens 8 to be tested. The light beam emitted from the test lens 8 passes through the relay lens 10c, is reflected by the prism 223, and is directed to the aforementioned second photometric optical path 226.
and enters the mask 13a. Here, the light flux incident on the mask 13a is transmitted to the image rotator 2.
The mask 13a is rotated by a predetermined angle by the action of the mask 13a.
incident on the Thereafter, the light flux emitted from the mask 13a is detected by the line sensors 15 and 16 in the same manner as described above.

In all the embodiments described above, a CCD was used as an example of a line sensor, but the line sensor according to the present invention is not limited to a CCD.
Photoelectric scanning using an image pickup tube and mechanically or optically scanning a photoelectric light emitting device in a straight line are also included in the concept of a line sensor according to the present invention.

Furthermore, the present invention is not limited to the configuration of each embodiment, and the embodiments may be combined as needed, or the constituent elements of each embodiment may be replaced with their equivalents. It goes without saying that this is also included within the scope of rights within the scope of the claims written by the applicant.

[Brief explanation of drawings]

Figures 1 and 2 are perspective views of a projection system showing the principle of the present invention, and Figures 3 a, b, and c show the relationship between the projection of a mask pattern and the line sensor, showing that optical characteristics can be measured by the present invention. 4 is a schematic diagram showing the relationship between the orthogonal coordinate system and the oblique coordinate system.
6 is a schematic diagram of an optical system showing an embodiment of the present invention. FIGS. 7a and 7b are front views showing an example of a mask pattern. 8 is a schematic diagram showing the projection of the mask pattern onto the line sensor and its detection state; FIGS. 9A to 9M are timing chart diagrams showing the relationship between the detection output by the line sensor and coordinate values;
Figure 0 is an element arrangement diagram of the line sensor showing a method of determining coordinate values from the detection output of the line sensor.
11, 12, and 13 are schematic diagrams for explaining measurement according to the principle of the present invention, FIG. 14 is a block diagram showing an example of an arithmetic circuit, and FIG. 15 is a second embodiment of the present invention. Schematic diagram of an optical system showing an example, 1st
6 is a diagram showing an arrangement of line sensors according to a third embodiment of the present invention, FIG. 17 is a partial schematic diagram of an optical system according to a fourth embodiment of the present invention, and FIG. 18 is a diagram showing an arrangement of line sensors according to a third embodiment of the present invention. 19A to 19F are diagrams showing the configuration of a mask according to the fifth embodiment, and FIG. 20 shows the relationship between the line sensor and the mask pattern image in the fifth embodiment. 21 is a partial schematic diagram of the optical system showing the sixth embodiment, and FIG.
The figure is an optical layout diagram showing the seventh embodiment, FIG. 23 is an optical layout diagram showing the eighth embodiment, and FIG. 24 is an optical layout diagram showing the ninth embodiment.
FIG. 3 is an optical layout diagram showing an example. 2, 2a, 2b...
Light source, 6... Collimator lens, 8... Test lens, 13a, 13b, 200... Luminous flux limiting mask, D... Detection surface, 10... Relay lens, 14
...Half mirror, 15, 16...Line sensor, 220...Image rotator.

Claims (1)

[Scope of Claims] 1. Collimator means for converting light from a light source into a parallel light beam, mask means for passing a part of the light beam from the collimator means, and a test optical system between the collimator means and the mask means. a retaining means for retaining the
An optical characteristic measuring device for an optical system, comprising: a detection means for detecting a light flux passing through the mask means; and an arithmetic device for calculating optical characteristics of the optical system to be tested from the detection result; a first optical path splitting means for splitting a light beam into at least two optical paths; and the masking means having at least two parallel straight line patterns on each of the optical paths split by the first optical path splitting means. 1. An optical characteristic measuring device for an optical system, characterized in that each sheet is arranged such that the linear patterns are arranged in different directions. 2. In claim 1, second optical path splitting means is disposed behind each of the masking means to divide the light beam passing through the masking means into at least two parts, and the second optical path splitting means splits the light beam into at least two parts. An optical characteristic measuring device for an optical system, characterized in that at least two light beams are made incident on at least two of the detection means, respectively. 3. An optical characteristic measuring device for an optical system according to claim 1 or 2, wherein the detection means is at least two line sensors that linearly scan and detect optical information. 4. The optical characteristic measuring device for an optical system according to claim 3, wherein the line sensor is composed of a CCD. 5 In claim 3 or 4, the line sensor is connected to the test optical system and the first
An optical system formed by a relay optical system disposed between optical path splitting means, wherein at least two optical systems are arranged so as to intersect with each other within a detection plane that is optically conjugate with the line sensor. Optical property measuring device. 6. In claim 3 or 4, the line sensor is optically connected to the line sensor formed by a relay optical system disposed between the test optical system and the first optical path splitting means. 1. An optical characteristic measuring device for an optical system, characterized in that the devices are arranged parallel to each other within a conjugate detection plane. 7. The optical characteristic measuring device for an optical system according to claim 1, wherein the detection means is a two-dimensional sensor. 8. In any one of claims 1 to 6, the light source includes at least two light sources with different emission wavelengths, and the first optical path splitting means wavelength-selectively reflects the light from the light source. Or an optical characteristic measuring device for an optical system characterized by transmission. 9. In any one of claims 1 to 6, each of the at least two optical paths divided by the first optical path dividing means includes a light shielding means for alternately and contradictoryly blocking the light beams. An optical characteristic measuring device for an optical system, characterized in that: 10 In any one of claims 1 to 9, the arithmetic device calculates a linear equation of the straight line pattern projected image from the detection result of the detection means, and calculates the inclination and pitch of the projected image from this equation. An apparatus for measuring optical characteristics of an optical system, characterized in that the optical characteristics of the optical system to be tested are determined by determining changes. 11. In any one of claims 1 to 10, the arithmetic device creates a virtual parallelogram from a position on the detector detected by the detector of the linear pattern projected image, and 1. An optical characteristic measuring device for an optical system, characterized in that the optical characteristics of a test optical system are calculated from changes when a rectangular test optical system does not exist in a measurement optical path and when it does exist. 12. In any one of claims 1 to 11, at least one straight line pattern of the group of straight line patterns of the mask means has a thickness or a light transmission characteristic different from other straight line patterns. An optical characteristic measuring device for an optical system, characterized by: 13 Collimator means for collimating the light from the light source, mask means for allowing part of the light beam from the collimator means to pass through, and holding means for holding the optical system to be tested between the collimator means and the mask means. , an optical characteristic measuring device for an optical system, comprising: a detection means for detecting a light beam passing through the mask means; and an arithmetic device for calculating optical characteristics of the optical system to be tested from the detection result, wherein the light sources have emission wavelengths different from each other. at least two sets of parallel straight line group patterns each consisting of at least two parallel straight line patterns are arranged in the mask means such that the straight line patterns are arranged in different directions; The wavelength transmission characteristics of the parallel straight line group patterns are configured to be different from each other, and an optical path dividing means for dividing the light beam passing through the masking means into at least two is disposed behind the masking means, What is claimed is: 1. An optical characteristic measuring device for an optical system, characterized in that at least two light beams divided by a dividing means are respectively made incident on the detecting means. 14. The optical characteristic of the optical system according to claim 13, wherein at least one straight line pattern of the parallel straight line group patterns has a different thickness or transmittance from other straight line patterns. measuring device. 15. The optical characteristic measuring device for an optical system according to claim 13 or 14, wherein the detection means is at least two line sensors that linearly scan and detect optical information. . 16. In any one of claims 13 to 15, the detection means detects at least two points on each projected image of the linear pattern, and determines the straight line of the projected linear pattern based on the detection results. An apparatus for measuring optical characteristics of an optical system, characterized in that the optical characteristics of the optical system to be tested are determined by calculating an equation and determining changes in the inclination and pitch of a projected image from this equation. 17 In claim 15, the arithmetic device creates a virtual parallelogram from the position of the straight line pattern projected image on the detector detected by the detector, and creates a virtual parallelogram in the optical system under test of the virtual parallelogram. What is claimed is: 1. An optical characteristic measuring device for an optical system, characterized in that the optical characteristics of an optical system to be measured are calculated based on the change in the case where the optical system does not exist in the measurement optical path and when the optical system exists. 18 Collimator means for collimating the light from the light source, mask means for allowing part of the light beam from the collimator means to pass through, and holding means for holding the optical system to be tested between the collimator means and the mask means. , an optical characteristic measuring device for an optical system, comprising: a detection means for detecting a light beam passing through the mask means; and an arithmetic device for calculating optical characteristics of the optical system to be tested from the detection result. It has a rotating means for rotating the emitted light beam and the mask means relative to each other about a measurement optical axis, and the mask means has at least two parallel linear patterns. Optical property measuring device for optical systems. 19. The optical characteristic measuring device for an optical system according to claim 18, wherein the rotating means is a rotating means for rotating the mask means. 20. The optical characteristic measuring device for an optical system according to claim 18, wherein the rotating means is a light beam rotating means for optically rotating the light beam emitted from the optical system to be tested. 21. The optical system according to claim 20, characterized in that the light beam emitted from the optical system to be tested is split into at least two optical paths, and the light beam rotating means is disposed in at least one of the optical paths. Optical property measuring device. 22. According to any one of claims 18 to 21, at least one straight line pattern of the parallel straight line group patterns has a different thickness or transmittance from other straight line patterns. Optical property measuring device for optical systems. 23. The optical characteristic of the optical system according to any one of claims 18 to 22, wherein the detection means is at least two line sensors that linearly scan and detect optical information. measuring device. 24. In any one of claims 18 to 23, the detection means detects at least two points on each projected image of the straight line pattern, and determines the linear equation of the projected straight line pattern from the detection results. An apparatus for measuring optical characteristics of an optical system, characterized in that the optical characteristics of the optical system to be tested are determined by calculating the equation and determining changes in the inclination and pitch of a projected image from this equation. 25 In claim 23, the arithmetic device creates a virtual parallelogram from a position on the detector detected by the detector of the linear pattern projection image, and generates a virtual parallelogram in the optical system under test of the virtual parallelogram. What is claimed is: 1. An optical characteristic measuring device for an optical system, characterized in that the optical characteristics of an optical system to be measured are calculated based on the change in the case where .