JPH0310898B2 - - 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. 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 U.S. patented device aims to determine the optical characteristics of the test lens from the polarization of the emitted light by making parallel light incident on the test lens parallel to the measurement optical axis. , 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.

There is an apparatus described in US Pat. No. 4,180,325 that can solve the enormous information processing problem associated with such two-dimensional plane detection. This device intermittently blocks multiple light beams that have passed through the mask aperture using a rotating disk with a special pattern consisting of transparent and opaque areas, and allows each light beam to arrive at the detector at different times. , is configured to eliminate the need to determine the correspondence between the aperture on the mask and the light beam 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.

That is, in the optical property measuring device according to the present invention, the mask placed behind the test lens has a pattern consisting of at least three straight lines that intersect substantially or virtually at at least three points, The detection unit is characterized by being provided with a linear sensor that detects the linear pattern at a position corresponding to two oblique axes or a position corresponding to two parallel axes. In the detection part, two linear sensors may be arranged diagonally or in parallel, but
In a preferred embodiment, the light beam passing through the mask is divided into two separate optical paths and guided to the detection section, and one of the light paths is provided with means for rotating the light beam passing therethrough by a predetermined angle around the optical axis. Thus, one linear sensor can detect two oblique axes. Further, detection can also be performed by disposing a parallel moving optical member in one optical path. In this case, two light emitting diodes with different emission wavelengths are used as light sources, and the light of one wavelength is passed through one optical path, and the light of the other wavelength is passed through the other optical path. By making the light passing through the sensor alternately incident on the sensor, or by providing a means such as a chopper, it becomes easy to distinguish information from the two optical paths.

When the light that has passed through the lens to be tested is passed through a mask having a pattern consisting of at least three straight lines that intersect with each other substantially or virtually, this straight line pattern will change depending on the refractive properties of the lens to be tested. cause bias. That is, when the lens to be tested has spherical refractive power, the intersecting angle of these straight line patterns does not change, but the length between the intersecting points changes according to the magnitude of the refractive power. Further, if the lens to be tested has a cylindrical refractive power, not only the length between the intersection points but also the intersection angle of the straight line pattern changes. When this projected pattern hits the linear sensor of the detection section, a change in the projected pattern due to the optical characteristics of the lens to be tested appears as a change in the position of the intersection between the projected image of each straight line and the linear sensor. Therefore, by detecting the intersection position using a linear sensor along two oblique or parallel axes and performing necessary calculations, the optical characteristics of the lens to be tested can be determined.

According to the present invention, it is not necessary to detect a coordinate point on a plane, and therefore a scanning means on a plane is not required, and detection can be performed only by a linear sensor. It is much simpler than the conventional method, and the device can be constructed at a low cost.
Furthermore, since there is no need to move the rotation pattern or the sensor, the device can be simplified and error factors can be reduced. Further, according to the principle of the present invention, the equation for calculation is simple, and the calculation unit can be simplified.

Below, the principle and embodiments of the present invention will be explained with reference to the drawings. First, in Fig. 1, the test lens L _s
is located in a plane with Cartesian coordinates X _p −Y _p ,
It has a first principal radial line r1 and a second principal radial line r2, its optical center O _p is on the coordinate origin, and the first principal radial line r
1 is inclined by θ _r1 with respect to the X _p axis.
There is _{an X-Y plane} having orthogonal coordinates X-Y with the origin placed on the measurement optical axis, which is separated by △d from the X p -Y p plane in the optical axis direction of the measurement optical path, and the mask M
is placed. A pattern consisting of three straight lines A, B, and C that intersect with each other is formed on the mask M.
The intersection of straight lines A and B is i, the intersection of straight lines A and C is j,
Let k be the intersection of straight lines B and C. Let the angle between straight line A and the X-axis be θ ₁ , the angle between straight line B and the X-axis be θ ₂ , the length of line segment ij be lA, and the length of line segment ik be lB.

Orthogonal coordinates X′-Y′ 1 and ₁ with the origin placed on the optical axis, separated by a distance d from the
Assuming that the _{detection plane} The projection lines A′, B′, and C′ are obtained at . Intersection i on mask M,
Let the intersection points corresponding to j and k be i′, j′, and k′, respectively,
Also, the angles that straight lines A′ and B′ make with the X′ axis are θ ₁ ′,
θ ₂ ′, the length of line segment i′−j′ is lA′, and line segment i′−k′
Let the length of be l′ _B. Here, tanθ ₁ = m _A , tanθ ₂ = m _B ,
Letting tanθ ₁ ′=m _A ′ and tanθ ₂ ′=m _B ′, the imaging point or focal line of straight lines A and B by this test lens L _s , that is, the angle θ between straight lines A and B is θ. =
If the distances from the mask M to the point where θ=180° are Z ₁ and Z ₂ respectively, then the lens to be tested L _s
The refractive power of is obtained as the following quadratic equation. _A・_B (m _A −m _B ) (d/Z+1) ² − [ _A (m _A −m _B ′)+ _B (m _A ′ −m _B )](d/Z+1) +(m _A ′−m _B ′)=0……(1) However, Therefore, if the two roots of equation (1) are respectively 1/Z ₁ and 1/Z ₂ , then Z ₁ and Z ₂ are the distance between the first focal line and second focal line of the test lens L _s and the mask surface. represents the distance in the optical axis direction between In this case, the vertex refractive powers 1/fr ₁ and 1/fr ₂ of the lens L _s to be tested are expressed by the following equation from the distance Δd between the lens L _s to be tested and the mask M.

1/fr ₁ = 1/Z ₁ /△d/Z ₁ −1 ………(2) 1/fr ₂ = 1/Z ₂ /△d/Z ₂ −1 ………(3) Also, the cylinder axis The angles θ _r1 and θ _r2 are expressed by the following equations.

θ _r2 = θ _r1 +90° ………(4) θ _r1 = tan ^-1 [m _A・_A・(1+d/Z)−m _A ′/ _A (
1+d/Z1) _-1 ]
………(5) θ _r1 = θ _r2 −90° ………(6) θ _r2 = tan ⁻¹ [m _A・_A (1+d/Z ₂ )−m _A ′/ _A (1
+d/Z ₂ )-1]......(7) In the present invention, the projected images A', B', and C' of these straight lines A, B, and C on _the X'-Y' plane are Y′ ₂
By detecting the position intersecting the axis, the position of each straight line on the X'-Y' plane is known, and the refractive power of the lens to be tested _Ls is calculated based on the above equation. That is, as shown in Fig. 2, the projection straight line intersects the Y′ ₁ axis at y ₁ , y ₂ , y ₃ ,
Intersects the _Y′2 axis at y ₄ , y ₅ , and y ₆ . Therefore, from y ₂ and y ₆ we get the equation of the line A′, and from y ₁ and y ₄
The equation of the line B' is obtained from y ₃ and y ₅ , and the equation of the line C' is obtained from y 3 and y 5. Then, based on the equations of these straight lines, the lengths l A ′, l _B ′ and slopes m _A ′, m _B ′ of straight lines A′ and _B ′ can be found,
It is also possible to find the coordinates of the intersections i', j', and k' of the straight lines. In this case, in order to determine which straight line projection images the points y ₁ , y ₂ , y ₃ , y ₄ , y ₅ , and y ₆ correspond to, it is necessary to change the width of the straight lines in the mask pattern, or A method such as using a group of two or three straight lines instead of one straight line may be used. As the straight line pattern on the mask, it is desirable to use an arrangement in which two sets of parallel straight lines are orthogonal to each other. If the projection of the intersection of straight lines is located on the coordinate axis, the center position of the straight line can be changed even if the widths of the straight lines are different or if multiple straight lines are used instead of one straight line. It may be difficult to calculate, but this problem is caused by the pattern on the mask.
This problem can be solved by cutting one of the straight lines at the intersection of the straight lines and creating an appropriate gap.

To calculate the prism refractive power, in the mask pattern consisting of three straight lines, take the intersection points so that x _i + x _j + x _k = 0, y _i + y _j + y _k = 0, and place them on the detection surface. All you have to do is find the coordinates of the corresponding point in . If the mask pattern is made up of two sets of parallel straight lines that intersect with each other, the intersections of the diagonals of the rectangle formed by the intersections of the straight lines may be found, and the amount of deviation of the intersections may be calculated.

FIG. 3 is an example of an oblique coordinate system X'-Y' that intersects at an angle γ on the detection plane. In this case, as shown in Fig. 4, the projected straight line is the point x′ ₁ ,
intersect at x′ ₂ , x′ ₃ and y′ ₁ , y′ ₂ , y′ ₃ , and the points x′ ₃ and y
' ₃ and
y′ ₂ gives the equation of straight line A′, points x′ ₁ and y′ ₁ give the equation of straight line B′, and points x′ ₂ and y′ ₃ give the equation of straight line C′. Here, when there is a relationship as shown in FIG. 5 between the oblique coordinate system X'-Y' on the detection surface and the coordinate system X-Y on the mask surface, the oblique coordinate system X'-Y' The transformation from the orthogonal coordinate system X-Y is
It can be converted using the following equation x=x′sinα+y′sinβ+ξ y=−x′cosα+y′cosβ+η ………(8), and then calculated using equations (1) to (7) to convert the lens to be tested L _s The optical properties of can be calculated. Alternatively, in calculating the refractive power and astigmatism axis in the first principal radial line r ₁ and the second principal radial line r ₂ , the projection straight line when the test lens L _s is not inserted into the measurement optical path is crossed obliquely −Y′ coordinate system, and use this value as the initial value. Next, the test lens L _s
is inserted into the measurement optical path, detected and calculated in the same manner, and the refractive characteristic of the lens to be tested can be measured by taking the difference from the initial value. In this way, the present invention is a device that is independent of how the coordinate system is determined, and as described in the following embodiments, when the linear sensor is arranged along each axis of the Since the position can be arbitrarily set independently of the X-Y coordinate system on the mask, this is an extremely advantageous feature in terms of device manufacturing and maintenance management.

Furthermore, as shown in FIG. 6, the straight lines A, B, and C are not actual intersections on the mask M, but virtual intersections,
j. This means that the present invention can generate projected images of straight lines A, B, and C, and
The intersection point with each axis of the Y′ coordinate system is detected, the equation of the straight line is obtained from this detected point, and the positions of the intersection points i′, j′, and k′ are calculated based on this equation. Therefore, the intersections i, j, and k do not actually need to exist as a pattern. In addition, as shown in FIG. 7, the straight lines A, B, and C do not need to form a triangle on the mask M.
By extending each, triangles i, j, and k can be virtually formed. Similar to the above-mentioned principle, such straight lines A, B, and C are also changed by the refractive characteristics of the lens _Ls to be tested, and form projected straight line images A', B', and C' on the detection surface. That is, as shown in Fig. 8, straight lines A, B,
C is the X'-Y' oblique coordinate system on the detection plane, where x' ₁ , x' ₂ ,
x′ ₃ and y′ ₁ , y′ ₂ , y′ ₃ are detected, and the equations of straight lines A′, B′, and C′ can be calculated respectively using the same principle as in Fig. 4. Therefore, this calculated straight line A′、B′、
Virtual triangles i′, j′, and k′ can be calculated from the equation of C′. And virtual triangles i, j, k and virtual triangles
From i′, j′, and k′, the refractive characteristics of the lens to be tested can be similarly calculated using equations (1) to (7).

To calculate the prism refractive power, calculate and memorize the following in advance from triangles i, j, and k formed by straight lines A, B, and C: X=x _i +x _j +x _k Y=y _i +y _j +y _k (9) Then, from straight lines A′, B′, and C′, i′j′,
k′ and find X′=x′ _i +x′ _j +x′ _k Y′=y′ _i +y′ _j +y′ _k (10), the horizontal and vertical prisms P _H , P _V
can be calculated as follows.

Here, A=Xcosθ _r1 +Ysinθ _r1 B=Xsinθ _r1 −Ycosθ _r1 ......(12) For the coordinates shown in Figure 5, if calculated by performing the transformation of equation (8), P _H , This shows that it is possible to obtain P _V.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 9 is a schematic diagram showing the optical system of a lensmeter adopting the principle of the present invention, in which two light emitting diodes 1 and 2 with different emission wavelengths are provided, and the light from these light emitting diodes 1 and 2 is , are directed to the optical path splitter 5 through collimator lenses 3 and 4, respectively. The optical path splitter 5 has wavelength selectivity, and reflects the light of a specific wavelength out of the light from the light emitting diode 1 towards the mirror 6, and reflects the light of a specific wavelength out of the light from the light emitting diode 2. is transmitted toward mirror 6. A test lens 7 is placed on the reflected optical path of the mirror 6, and a mask plate 8 is placed behind it.

A relay optical system 10 is provided to enable detection at a detection surface 9 located a predetermined distance away from the mask plate 8 in the optical axis direction. The relay optical system 10 includes an optical path splitter 11 having wavelength selectivity similar to that of the optical path splitter 5.
reflects the light beam emitted from the light emitting diode 1 in the direction of the optical path 12, and transmits the light beam emitted from the light emitting diode 2 in the direction of the optical path 13. Optical path 12
A relay lens 14, a mirror 15, and a relay lens 16 are arranged, and the light beam transmitted through the relay lens 16 reaches an optical path splitter 17 having wavelength selection characteristics similar to those of the optical path splitter 11. Similarly, a relay lens 18 , a mirror 19 , and a relay lens 20 are arranged in the optical path 13 , and the light beam exiting the relay lens 20 is incident on the optical path splitter 17 . Further, an image raw data 21 is provided between the relay lens 18 and the mirror 19 for rotating the image by a predetermined angle γ different from 90°. Optical path splitter 17
The light beam incident on the optical path splitter 17 is directed toward the optical path 22 by the action of the optical path splitter 17. A concave lens 23 and a linear sensor 24 are arranged on the optical path 22. This concave lens 23 is for preventing the mask image projected onto the sensor 24 from becoming too small when the test lens 7 is a strong positive lens. The linear sensor 24 is
It is placed at a position conjugate to the detection surface 9.

As shown in FIG. 10a, a straight line pattern is formed on the mask 8, consisting of a first set of parallel straight lines 25 and 26 and a second set of parallel straight lines 27 and 28 that intersect therewith. Each of the straight line groups 27 and 28 consists of three relatively thin straight lines, and the straight lines 25 and 26
Each of is a relatively thick straight line. In addition, as shown in FIG. 10b, the intersection of each straight line is such that the straight line group 27 or 28 made of thin lines is cut at the intersection, and does not directly overlap with the straight line 25 or 26 made of thick lines. There is. The pattern on the mask 8 may be such that the linear portion is transparent and the remaining portion is opaque, or the linear portion is opaque and the remaining portion is transparent.

The light that enters the test lens 7 as parallel light and passes through the test lens 7 passes through the transparent portion of the mask plate 8 and advances to the relay optical system 10 . Relay optical system 10
The light that has reached the linear sensor 24 through the
It will look like Figure 1. Here, the intersection points of each straight line or group of straight lines with the coordinate axes x′, y′ are x′ ₁ , x′ ₂ , x′ ³ , x′ ₄ , y′ ₁
,
By determining y′ ₂ , y′ ₃ , and y′ ₄ and performing necessary calculations, the refractive power of the lens 7 to be tested can be obtained.
In the illustrated embodiment, two light emitting diodes 1 and 2 having different emission wavelengths are alternately blinked, and the light from one light emitting diode 1 passes from the optical path 12 to the optical path 22 and reaches the linear sensor 24. death,
For example, detection is performed on the x' axis, and the light from the other light emitting diode 2 reaches the linear sensor 24 via the optical path 22 from the optical path 13 having the image rotator 21, and detection is performed on the y' axis.

Next, referring to FIG. 12, a flip-flop 33 is connected to the light emitting diodes 1 and 2 for driving them.
is activated by a scan start pulse from the drive circuit 35. As the linear sensor 24, for example, a CCD consisting of 1728 elements is used, and its output is amplified by an amplifier 36 and given to a sample and hold circuit 37. Sample hold circuit 3
The output of 7 is given to a comparator 38, which comparator 38
It is compared with a reference value from the reference setter 39 and binarized to produce an output 701. Drive circuit 3
5 generates a scan start pulse 702 and a clock pulse 703, and these pulses are applied to the sensor 2.
given to 4. FIG. 13 shows various pulses, in which a shows the scan start pulse, b shows the clock pulse, c shows the output pulse of the sample and hold circuit 37, and d shows the output of the comparator 38.

In such an arrangement, when scanning is performed by the sensor 24, it is necessary to detect which position on the sensor 24 the projection of each straight line of the mask pattern has reached. To do this, the center of the output pulse corresponding to the width of the pattern straight line must be at the sensor 24.
It is sufficient to detect which sensing element is on the output pulse. For example, the purpose can be achieved by calculating the midpoint between the rise and fall of each output pulse using a clock pulse. The first circuit for this purpose is
It is shown in Figure 5. In FIG. 14, an output 701 from the comparator 38 is applied to a rising edge detector 40a and a falling edge detector 40b, and a scan start pulse 702 and a clock pulse 703 are applied to a counter 41. Counter 41 is first cleared by scan start pulse 702 and then counts clock pulses 703. The output of the counter 41 is sent to a latch circuit 44.
The latch circuit 44 latches the output of the counter 41 at the rising edge detector output 101. The output of the latch circuit 44 at this time represents the position on the sensor 24 of the front end of the pulse _L1 in FIG. 13, for example. During the period when the output pulse 701 is "1", the gate circuit 42 operates the counter 4 which has been cleared in advance by the scan start pulse 702.
Supply clock pulses to 3. Gate circuit 42
The output of is shown as g in FIG. Therefore, the output of the counter 43 shows a value equal to the slit width projected onto the sensor 24. If the counter 43 is a binary counter, the adder 4 adds the value obtained by discarding the least significant bit of the output of the gate circuit 42 and shifting it by one bit toward the lower bit, and the output of the latch circuit 44.
7, the position of the center of the slit projected onto the sensor 24 is determined. 46
is a delay circuit, and the output 10 of the falling detector 40
2 by Δt. This state is shown as f in FIG. 15. The output of the delay circuit 46 is provided to a counter decoder 48. 48 sequentially latches the output of the adder 47 191,1
This is to latch up to 92...198.
Note that the output of the delay circuit 46 is also used to reset the counter 43.

With the above circuit, when one scan of the sensor 24 is completed, the latch 191 stores the center position of the pattern straight line that appears first on the sensor, and the latch 192 stores the center position of the second slit. Ru. For example, when sensor 24 scans along the Y' axis in FIG.
4, signals corresponding to eight slits appear as shown in FIG. 13c. Therefore, eight circuits 191 to 198 are required for the latch circuit.

In FIG. 14, 45 is a digital comparator which compares the output of the reference value generator 50 and the output of the counter 43 and supplies a comparison output to the latches 191-198. This is to determine whether the data represents the position of the landing point on the sensor by a thick straight line in the mask pattern or by a thin straight line. Therefore, the output of each latch is sent to the determination circuit 51 together with information on the position of the center of the slit and information on the size of the slit width. The reason why the mask pattern is composed of one thick straight line and three thin straight lines is to facilitate the discrimination of the straight lines projected onto the sensor 24, as described above. This will be explained in detail using FIG. 17.
FIG. 17 is an enlarged view of the intersection of the straight lines. 25 is a thick straight line, and 27 is three straight lines that are thin enough to be easily distinguished from 25.
This is a straight line group consisting of 7-1, 27-2, and 27-3.

Now, if the sensor 24 scans the pattern at position a or e, the center of the thick straight line 25 is determined to be the position of the straight line on the sensor, and the center of the central straight line 27-2 of the three thin straight lines is determined as the position of the straight line on the sensor. The position of the straight line group 27 can be detected. When the pattern is scanned at position b, the sensor 24 has straight lines 25, 27-
2 and 27-3 appear, and at the position c, the straight lines 27-1, 25, 27-3 are outputted, and at the position d, the straight lines 27-1, 27-2, 25 are outputted in that order. Therefore, when only two thin straight lines are projected onto the sensor, the position of the center of each straight line and group of straight lines can be detected and determined by performing the following determination.

(1) Always make the center position of the sensor output by a thick straight line the position of the straight line 25 detected on the sensor.

(2) When three thin straight lines appear in the sensor output, the center position of the intermediate straight line is taken as the position of the straight line group 27 detected on the sensor.

(3) When only two thin straight lines are output, (a) If the order is thick, thin, thin, then the center of the first thin line, (b) If the order is thin, thick, thin. For example, the center position between two thin straight lines is (c) If the order is thin, thin, thick, then the center of the second thin line is the position of straight line group 27 detected on the sensor. .

The above determination is made by the determination circuit 51 shown in FIG. Although it is possible to construct the determination circuit 51 using random logic, it is preferable that the subsequent data processing including the determination circuit be performed by a microprocessor.
It would be easy for those in related industries to use a microprocessor to make the above decisions.

Although the above explanation concerns the intersection of the straight line 25 and the group of straight lines 27, it goes without saying that other intersections can be determined using the same method. Note that as sensor output, outputs corresponding to four intersections are output in one scan,
Divide into two sections at the center of the sensor,
By making the above determination for each division, the sensors on the sensors y' ₁ , y' ₂ , y' ₃ , and y' ₄ shown in FIG. 16 can be detected.

FIG. 18 shows an example of the overall configuration of a lens meter based on the measurement principle described above. In FIG. 18, 700 is constituted by the circuit shown in FIG. 12 and the optical system shown in FIG. Reference numeral 1000 is composed of the circuit shown in FIG. 14, and inputs the position of each straight line of the mask pattern on the sensor to the microprocessor 52. microprocessor 5
2 is composed of a data memory section 53, a program memory section 54, a display interface section 55, a printer interface section 57, and a group of output registers 291 to 295 for outputting the results of calculations by the microprocessor.
In the field of microprocessors, it is easy to achieve such a configuration.

With one scan of the first sensor, y′ ₁ , y′ ₂ , y′ ₃ ,
Once the position of y′ ₄ is obtained, the light emitting diode illuminating the mask is switched for the next scan. When the light emitting diodes are switched, the emission wavelength is different, so the optical path by the optical system is switched, equivalently causing the sensor to scan along the x' axis in FIG. 16. Therefore, the positions of x′ ₁ , x′ ₂ , x′ ₃ , and x′ ₄ on the sensor are determined.

Once the position of the straight line pattern on the sensor 24 is determined in this manner, the optical characteristics of the lens to be tested are calculated by the following calculation process.

() Find the equations of straight lines 25, 26 and straight line groups 27, 28, and calculate the slope of straight line group 27 by m' _A and straight line 26.
Let the gradient of be m′ _B.

() Find the length of the straight line group 27 sandwiched between the straight lines 25 and 26, and let that length be l' _A.

() Find the length of the straight line 26 sandwiched between the straight line groups 27 and 28, and let that length be l' _B.

() Calculation of prism refractive power is shown in Figure 16i,
Let the coordinates of j, k, l be (x′ _i , y′ _i ),
(x′ _j , y′ _j ), (x′ _k , y′ _k ), (x′ _l , y′ _l ), horizontal prism refractive power P _H (X-axis direction),
and vertical prism refractive power P _V (Y-axis direction)
Extend equations (9) and (10) to the case of four intersections, and set X=x _i +x _j +x _k +x _l Y=y _i +y _j +y _k +y _l ......(9)' _{From the intersection on the detection plane ,} find By forming a straight line pattern on the mask in advance so that Y=0, equation (11) can be Calculate as. Here, d is the distance between the mask M and the detection surface.

() A microprocessor performs arithmetic processing based on the equations described above to obtain the required optical characteristics.

The results obtained in this manner are output as cylindrical power, spherical power, astigmatic axis angle, and prism refractive power to the display 56, printer 58, and output registers 291 to 295 shown in FIG. 18. still,
The display 56 is equipped with a device capable of two-dimensional display (for example,
By using a CRT (display device, etc.),
The prism refractive power and astigmatic axis angle can be displayed as a two-dimensional pattern. By doing this, there is an advantage that alignment between the lens to be examined and the lens meter can be easily and quickly performed.

FIG. 19 shows a second embodiment of the present invention. Components having the same functions as those in FIG. 10 are given the same reference numerals and explanations will be omitted. This example is based on the ninth
In the figure, instead of rotating the image using the image rotator 21, a parallel plane glass 301 is rotated along the optical axis 30.
By arranging the parallel plane glass 301 at an angle to the two, and changing the parallel plane glass 301 to the position (a) and the position (b), the sensor 24 can be placed at an angle to the two as shown in FIG.
The same effect can be obtained by moving the sensors 24 and 24' in parallel to the position 4', or by arranging the two sensors 24 and 24' in parallel.

When the sensor is at position 24, it detects points e ₁ to e ₄ , and when it is at position 24', it detects points e' ₁ to e' ₄ , and from this the equations of lines 25 to 28 can be calculated. , the optical characteristics of the lens 7 to be tested can be measured using the same calculations as in the first embodiment.

FIG. 21 shows a third embodiment of the present invention. In this embodiment, instead of rotating the parallel plane glass 301 of the second embodiment, the optical path incident on the linear sensor 24 is divided into two optical paths so that these optical paths are parallel to each other at the plane of incidence on the linear sensor 24. This configuration provides a lens meter without a rotation mechanism. In FIG. 21, components having the same functions as those in the first embodiment are given the same reference numerals and their explanations will be omitted. The light flux after passing through the mask 8 is
The optical path splitter 11 having wavelength selectivity separates the first optical path _I1 consisting of the splitter 11, lens 18, mirror 19, lens 20, and lens 23, and the splitter 11, lens 14, mirror 15, lens 16, and mirror 40.
0, and a second optical path _I2 consisting of a lens 23. Here, the mirror 400 is arranged so that its reflected light is shifted parallel to the first optical path _I1 by a distance e. The light emitted from the light emitting diode 1 is
It is made into parallel light by a lens 3, reflected by an optical path splitter 5 with wavelength selectivity, and then sent to a mirror 6, a test lens 7,
The sensor 2 passes through the mask 8 and the first optical path I ₁ mentioned above.
4 and is detected by the sensor. Next, when the light emitting diode 2 is switched to emit light, the light passes through a lens and a splitter 5, passes through a mirror 6, a test lens 7, a mask 8, and is reflected by a splitter 11. The sensor 2 passes through the second optical path described above.
4 and is detected by the sensor.

22a to 22f are diagrams showing a fourth embodiment of the present invention, and this is an embodiment related to the formation of a linear pattern of the mask 8. FIG. In the first, second and third embodiments, patterns 25, 26 and 27,
28 was made up of one line and three lines to differentiate them, but in this embodiment, the wavelength transmission characteristics of the patterns themselves are changed to differentiate them. Straight line pattern 3
Reference numeral 10, 311 has a wavelength selection characteristic as shown in FIG. 22e, and is formed of a thin film 312 that mirrors the wavelength λo and transmits wavelengths longer than λo. This configuration is shown in FIG. 22b as a sectional view taken along line A-A'. 22nd
In figure b, on the mask substrate 313 there is a 22nd
A thin film 312 having the characteristics shown in Fig. e is coated with a gap 314. On the other hand, straight line pattern 3
15 and 316 are formed of a thin film 317 having wavelength selection characteristics as shown in FIG. 22f. This thin film 317 transmits wavelengths shorter than wavelength λo.
The thin film 317 is also placed on the mask substrate 313 in the gap 3.
It is coated with 14. thin film 31
2 and the thin film 317 are coated on the mask substrate 313 with the gap 314 aligned at right angles, so that the patterns 310, 311, 31
The portion 318 surrounded by 5,316 is the membrane 312,
Since it is coated with two layers of 317, it becomes a part 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. 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.

FIG. 23 shows an embodiment of a lens meter according to the present invention having the above-mentioned mask 8'.
Components having the same functions as those in the first embodiment are given the same reference numerals, and explanations thereof will be omitted. Here, the light emitting diode 1 is a light emitting diode having wavelength characteristics shown by a broken line in FIG. 22e, and the light emitting diode 2 is a light emitting diode having wavelength characteristics shown by a broken line in FIG. 22f. When the light emitting diode 1 emits light, this light passes through the patterns 310, 311 on the mask 8' to form projected images 310', 311' as shown in FIG. When the light emitting diode 2 emits light, it passes through the patterns 315 and 316 on the mask 8' and forms a projected image 31.
5', 316' are formed. These projected images 310',
311', 315', 316' are the X' axis of the detection surface;
The linear sensor 24 arranged on the Y' axis selects the point _x'1 ~
x' ₄ and points y' ₁ to y' ₄ are detected, and the optical characteristics of the lens 7 to be tested are measured using the same calculation method as in the first embodiment. According to this embodiment, it is not necessary to distinguish patterns geometrically, and when patterns are distinguished geometrically, it is not possible to form a large number of patterns, considering the diffraction phenomenon of patterns, etc., but this embodiment According to the method, a large number of patterns can be formed on a mask, and therefore a large number of detection points can be taken by the sensor 24, and the detection points can be averaged, thereby improving measurement accuracy.

FIG. 25 shows a fifth embodiment of the present invention. This example shows a further modification in the case where the intersection of straight line patterns A, B, and C virtually has , as shown in FIG. ₁ , _a2 , _b1 ,
This shows a detection method in the case where b ₂ , c ₁ , and c ₂ are not present. To determine the equations of projected images A', B', and C' of linear patterns A, B, and C on the detection surface,
It is necessary to detect at least two points for each straight line image, so the linear sensor also includes at least four linear sensors S ₁ to S ₄ to detect each straight line image at two points as in this embodiment. Alternatively, as shown in FIGS. 19 and 20, if one linear sensor is used to rotate the parallel plane glass 301 and translate the projected image, it is necessary to move it to at least four positions. In addition, when using two sensors (for example, two sensors S ₁ and S ₃ in FIG. 25), the parallel plane glass 301 is rotated to two positions as in the second embodiment, and the projected image is Just shift it to one position.

FIG. 26 is a sixth embodiment of the present invention, and is an example in which a projected image from a mask pattern having virtual intersections and no extensions is detected by an oblique linear sensor, similar to FIG. 25. . In the case of this embodiment, at least four linear sensors S ₁ to _{S 4} are required, or in the embodiment of FIG. However, it goes without saying that it may be equivalent to use substantially four linear sensors. Also,
The embodiment shown in FIG. 10 can also be made into a four-division optical path, so that one linear sensor is equivalent to using four linear sensors.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a projection system showing the principle of the present invention;
FIG. 2 is a front view showing the mask projection pattern on the detection surface, FIGS. 3 and 4 show the mask pattern in an oblique coordinate system, and FIG. 5 shows the relationship between the oblique coordinate system and the rectangular coordinate system. , FIG. 6 shows an example of virtual intersection of straight line patterns, FIG. 7 is a perspective view showing another example of virtual intersection, FIG. 8 is a front view thereof, and FIG. 9 is one example of the present invention. A schematic diagram of an optical system showing an embodiment, FIGS. 10a and 10b show examples of mask patterns and their intersections, FIG. 11 shows a projection of the mask pattern onto an oblique coordinate system, and FIG. 12 shows calculations. A block diagram of a part of the circuit, FIG. 13 shows the signals obtained by detecting the projection mask pattern, and FIG.
The figure is a block diagram of a circuit connected to the circuit in Figure 12, Figure 15 shows pulses in the signal processing process, Figure 16 is a schematic diagram for explaining the scanning of a mask projection pattern, and Figure 17 is a cross-sectional diagram. FIG. 18 is a block diagram of an arithmetic circuit showing another embodiment of the invention, FIG. 19 is a schematic diagram of an optical system in another embodiment of the invention, and FIG. 20 is a sensor 21 is a schematic diagram of an optical system showing still another embodiment of the present invention; FIGS. 22 a to 22 f are schematic diagrams showing examples of mask patterns having wavelength selective characteristics; FIG. 23 is a schematic diagram of an optical system showing still another example, FIG. 24 shows a projection pattern, and FIGS. 25 and 26 show mask patterns according to still another example of the present invention. 1, 2... Light emitting diode, 3, 4... Collimator lens, 5, 11... Optical path splitter, 7... Test lens, 8... Mask plate, 9... Detection surface, 1
6, 18...Relay lens, 24...Linear sensor.

Claims (1)

[Claims] 1. A light source that projects a luminous flux onto a test optical system;
a device that is provided between the light source and the optical system to be tested, and converts the light beam from the light source into a parallel light beam; and a device that is provided behind the optical system to be tested, and selectively transmits the light beam that has passed through the optical system. a detection device disposed a predetermined distance from the mask in the optical axis direction, and a calculation device that calculates the optical characteristics of the optical system to be tested by calculating information obtained by the detection device. . An apparatus for measuring optical characteristics of an optical system, wherein the mask has a pattern consisting of at least three straight lines that substantially or virtually intersect at at least three points. 2. The device according to item 1 above, wherein the pattern of the mask consists of two sets of parallel line groups each consisting of a plurality of parallel lines, and two parallel lines perpendicular to these parallel line groups. 3. The device according to item 1 above, in which straight lines of the group of parallel lines are cut at intersections of the mask pattern so that they do not directly overlap with other straight lines. 4 In the first item, the arithmetic device includes a first calculation unit that calculates an equation of a straight line of the straight line group pattern projected image from the information detected by the detection device, and a first calculation unit that calculates an equation of a straight line of the straight line group pattern projection image from the information detected by the detection device; and a second calculation unit that calculates intersection coordinates of the image. 5 In the first item, the calculation device includes a first calculation unit that calculates the length of the straight line from the calculation result of the second calculation unit, and a calculation unit that calculates the length of the straight line from the equation of the straight line obtained by the first calculation unit. It has a second calculation unit that calculates the tilt angle, and a third calculation unit that calculates the refractive characteristics of the test lens from the calculation results from the first calculation unit and the calculation results from the second calculation unit. Device. 6. The device according to item 1 above, wherein the pattern of the mask is composed of at least two groups of parallel lines each having a different wavelength selection characteristic. 7 a light source that projects a luminous flux onto the optical system to be tested;
a device that is provided between the light source and the optical system to be tested, and converts the light beam from the light source into a parallel light beam; and a device that is provided behind the optical system to be tested, and selectively transmits the light beam that has passed through the optical system. a detection device disposed a predetermined distance from the mask in the optical axis direction, and a calculation device that calculates the optical characteristics of the optical system to be tested by calculating information obtained by the detection device. , the mask has a pattern of at least three straight lines intersecting substantially or virtually at at least three points, and the detection device has at least one line passing through the optical axis and disposed perpendicular to the optical axis. A linear sensor is provided between the mask and the detection device, and an optical path splitter that divides the light beam transmitted through the mask into at least two optical paths and a means for guiding the light beams of these divided optical paths to the linear sensor are provided. One of the optical paths divided by the optical path splitter is provided with a device for rotating the projected image by a predetermined angle other than 90°, so that detection in at least two oblique axes can be performed by at least one linear sensor. Optical property measuring device for Natsuta optical system. 8 In the above item 7, the light source is composed of two light emitting elements having different emission wavelengths, and the optical path splitter has a wavelength selection characteristic, and the light beam from one light emitting element is divided into one divided optical path and the other one. A device configured to pass a light beam from a light emitting element to the other divided optical path, and provided with means for switching the light emitting element every detection scan of the linear sensor. 9. The device according to item 7, wherein the pattern of the mask consists of two sets of parallel line groups each consisting of a plurality of parallel lines, and two parallel lines perpendicular to these parallel line groups. 10. The device according to item 7 above, in which the straight lines of the group of parallel lines are cut at intersections of the mask pattern so that they do not directly overlap with other straight lines. 11 In the above item 7, the calculation device includes a first calculation unit that calculates an equation of a straight line of the straight line group pattern projection image from the information detected by the detection device, and and a second calculation unit that calculates intersection coordinates of the image. 12 In the above item 7, the calculation device includes a first calculation unit that calculates the length of the straight line from the calculation result of the second calculation unit, and a calculation unit that calculates the length of the straight line from the equation of the straight line obtained by the first calculation unit. It has a second calculation unit that calculates the tilt angle, and a third calculation unit that calculates the refractive characteristics of the test lens from the calculation results from the first calculation unit and the calculation results from the second calculation unit. Device. 13 In the above item 7, the pattern of the mask has at least two patterns each having different wavelength selection characteristics.
A device consisting of a set of parallel lines. 14 A light source that projects a light beam onto the test optical system, a device that is provided between the light source and the test optical system and converts the light flux from the light source into a parallel light flux, and a device that is located behind the test optical system. a mask that selectively transmits the light beam that has passed through the optical system; a detection device that is disposed a predetermined distance from the mask in the optical axis direction; and a detection device that calculates information obtained by the detection device. the mask has a pattern consisting of at least three straight lines that substantially or virtually intersect at at least three points, and the detection device is arranged along the optical axis. arranged at right angles to and parallel to each other,
An optical characteristic measuring device for an optical system, comprising at least two linear sensors. 15. The device according to item 14, wherein the pattern of the mask consists of two sets of parallel line groups each consisting of a plurality of parallel lines, and two parallel lines perpendicular to these parallel line groups. 16. The device according to item 14 above, in which the straight lines of the group of parallel lines are cut at intersections of the mask pattern so that they do not directly overlap with other straight lines. 17 In the above paragraph 14, the arithmetic device:
a first calculation unit that calculates a straight line equation of the straight line group pattern projected image from information detected by the detection device; and a second calculation unit that calculates intersection coordinates of the straight line image from the straight line equation. A device comprising: 18 In the above paragraph 14, the arithmetic device:
a first calculation unit that calculates the length of the straight line from the calculation result of the second calculation unit; a second calculation unit that calculates the inclination angle of the straight line from the straight line equation obtained by the first calculation unit; An apparatus including a third calculation section that calculates the refractive characteristics of the lens to be tested from the calculation results from the first calculation section and the calculation results from the second calculation section. 19 A light source that projects a luminous flux onto the optical system to be tested, a device that is provided between the light source and the optical system to be tested and that converts the luminous flux from the light source into a parallel luminous flux, and a device behind the optical system to be tested. a mask that selectively transmits the light beam that has passed through the optical system; a detection device that is disposed a predetermined distance from the mask in the optical axis direction; and a detection device that calculates information obtained by the detection device. the mask has a pattern consisting of at least three straight lines that substantially or virtually intersect at at least three points, and the detection device is arranged along the optical axis. An optical member is provided between the mask and the detection device to move the transmitted light beam of the mask in parallel within the detection plane. An optical characteristic measuring device for an optical system that can perform detection in at least two axial directions. 20. The device according to item 19, wherein the pattern of the mask consists of two sets of parallel lines each consisting of a plurality of parallel lines, and two parallel lines perpendicular to these parallel lines. 21. The device according to item 19, in which the straight lines of the group of parallel lines are cut at the intersections of the mask pattern so that they do not overlap directly with other straight lines. 22 In the above paragraph 19, the arithmetic device:
a first calculation unit that calculates a straight line equation of the straight line group pattern projected image from information detected by the detection device; and a second calculation unit that calculates intersection coordinates of the straight line image from the straight line equation. A device comprising: 23 In the above paragraph 19, the arithmetic device:
a first calculation unit that calculates the length of the straight line from the calculation result of the second calculation unit; a second calculation unit that calculates the inclination angle of the straight line from the straight line equation obtained by the first calculation unit; An apparatus including a third calculation section that calculates the refractive characteristics of the lens to be tested from the calculation results from the first calculation section and the calculation results from the second calculation section. 24 A light source that projects a luminous flux onto the optical system to be tested, a device that is provided between the light source and the optical system to be tested and converts the luminous flux from the light source into a parallel luminous flux, and a device behind the optical system to be tested. a mask that selectively transmits the light beam that has passed through the optical system; a detection device that is disposed a predetermined distance from the mask in the optical axis direction; and a detection device that calculates information obtained by the detection device. the mask has a pattern consisting of at least three straight lines that substantially or virtually intersect at at least three points, and the detection device is arranged along the optical axis. between the mask and the detection device, and an optical path splitter that divides the light beam transmitted through the mask into at least two optical paths; One of the optical paths split by the optical path splitter is provided with a device for moving the projected image in parallel from the other optical path within the detection plane, and one linear sensor moves the projected image in parallel from the other optical path. An optical characteristic measuring device for optical systems that can perform detection in two axial directions. 25 In the above item 24, the light source is composed of two light emitting elements having different emission wavelengths, and the optical path splitter has a wavelength selection characteristic, and the light beam from one light emitting element is directed to one split optical path and the other is divided. A device configured to pass a light beam from a light emitting element to the other divided optical path, and provided with means for switching the light emitting element every detection scan of the linear sensor. 26. The device according to item 24, wherein the pattern of the mask consists of two sets of parallel lines each consisting of a plurality of parallel lines, and two parallel lines perpendicular to these parallel lines. 27. The device according to item 24 above, in which the straight lines of the group of parallel lines are cut at intersections of the mask pattern so that they do not overlap directly with other straight lines. 28 In the above paragraph 24, the arithmetic device:
a first calculation unit that calculates a straight line equation of the straight line group pattern projected image from information detected by the detection device; and a second calculation unit that calculates intersection coordinates of the straight line image from the straight line equation. A device comprising: 29 In the above paragraph 24, the arithmetic device:
a first calculation unit that calculates the length of the straight line from the calculation result of the second calculation unit; a second calculation unit that calculates the inclination angle of the straight line from the straight line equation obtained by the first calculation unit; An apparatus including a third calculation section that calculates the refractive characteristics of the lens to be tested from the calculation results from the first calculation section and the calculation results from the second calculation section. 30. The device according to item 24, wherein the pattern of the mask consists of at least two groups of parallel lines each having different wavelength selection characteristics.