JPH031833A - Optic refractive index measuring apparatus - Google Patents

Abstract

PURPOSE:To enable guaranteeing of accurate inspection of eyes by making a processing with a judgement that an error exists when an axial deviation between an optical system optical axis of a measuring light during the projecting of the measuring light and an optical axis of an eye to be inspected exceeds a reference value. CONSTITUTION:A projection pattern is given as a pattern of four spots facing one another sandwiching optical axes a1 and aE on a horizontal diameter and a vertical diameter on a cornea passing through the optical axis aE of an eye E to be inspected. Therefore, an optic refractive index of the eye to be inspected can be learned by measuring coordinates (Sx0, Sy0) and (Sx0, Sy9) of points S0 and S9 of an image formed on a light receiving sensor with an image recognition device corresponding to images at two points P0 and P9 on a horizontal (x) axis and on a vertical (y) axis a projected onto a cornea E1 by the spot pattern. When there is an axial deviation as angular deltaand horizontal x deviations between a measuring system optical axis a1 and the optical axis aE of the eye to be inspected, a spot image on the light receiving sensor is detected being affected by aberration or the like with the axial deviation exceeding x=+ or -1mm and delta=+ or -10 deg. thereby making correction unable to make. That is, a calculated value obtained is not adopted being regarded as unreliable.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an eye refractive power measuring device for measuring the eye refractive power of an eye to be examined.

[Conventional technology]

Generally, various refractometers are known as devices for measuring eye refraction. A refractometer is a device that measures the refractive power of the eye by observing a light target (measuring light) imaged on the fundus or retina of the eye to be examined through an optical system. In conventional devices, before projecting measurement light onto the eye to be examined, the positional relationship between the measurement optical system on the device side and the eye to be examined is adjusted to a measurable state, that is, to a focused and in-focus state. Therefore, since there is a slight elapsed time between the time of this adjustment and the time of emission of the measurement light, the subject's eye moves during this time, and as a result, the above-mentioned adjusted state is disrupted when the measurement light is emission. It is to be there. What is most likely to occur is optical axis misalignment between the optical axis of the eye to be examined and the optical axis of the measurement optical system. If the amount of misalignment is small, the measurement error can be ignored, but
If the amount of axis deviation is large, the measurement error is large and the measured value is unreliable. Therefore, in this case, it is necessary to handle the error. However, in conventional devices, such errors are ignored and no error processing is performed. For this reason, a situation arises in which the measured values include values with low reliability.

[Problem to be solved by the invention]

Therefore, the technical problem to be solved by the present invention is to detect the amount of deviation between the optical axis of the measurement optical system on the device side and the optical axis of the eye to be examined.
If the amount of deviation is greater than a predetermined value, the measured value is treated as unreliable.

[Means to solve the problem]

In order to solve the above problems, an eye refraction measuring device according to the present invention is configured as follows. That is, it includes an optical measuring section including a measurement optical system for measuring the eye refractive power of the eye to be examined, and a main body section that calculates the eye refractive power based on measurement data from the optical measuring section. The measurement optical system includes a measurement light projection optical system that projects measurement light and projects a projection pattern onto the retina of the eye to be examined, and a reflected light of the projection pattern image projected onto the retina of the eye to be examined. and a measurement light receiving optical system that receives the measurement light. The measurement light includes a total of four spot lights arranged every 90'' around the optical axis of the measurement light projecting optical system. 4
determination means for determining the amount of axial deviation between the optical axis of the measurement light optical system and the optical axis of the eye to be examined when the measurement light is projected, based on the relative positional relationship of the two spot light images with respect to the measurement light receiving optical system;
The apparatus includes means for comparing the amount of axis deviation with a reference value, and means for processing as a measurement error when the amount of deviation between the two axes is greater than or equal to the reference value.

[Action/effect]

In the above configuration, since two pairs of spot light sources are employed, the relative positional relationship between the images of the four spot lights and the optical axis of the eye to be examined, that is, the optical axis of the measurement light optical system and the optical axis of the eye to be examined. The amount of deviation can be detected accurately by relatively easy calculation. The determination means and error processing means allow the examiner to recognize that the measurement is an error when the amount of deviation between the two axes is large and the measurement is unreliable. Therefore, measurement results with large measurement errors can be excluded, thereby ensuring accurate eye examination.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the schematic configuration of the eye refraction measuring device of this embodiment. As shown in the figure, it is roughly divided into two configurations: an optical measurement section 1 and a main body section 2. The optical measurement section 1 has a built-in measurement optical system, and is constructed to have a size and weight that is of a so-called "non-day type" that can be easily held with one hand and moved freely. The main body section 2 has built-in an image recognition device 3 that recognizes the alignment of aiming and focusing based on the image signal from the optical measurement section I, and a monitor 4 that displays the image signal as an image. . In addition, both the image recognition device 3 and the monitor 4 output control signals to the optical measurement unit I while exchanging signals, and monitor the eye based on the measurement data obtained from the image signal input to the image recognition device 3. A microcomputer (hereinafter referred to as microcomputer) 5 that calculates the degree of refraction is also built-in. When the image recognition device 3 detects that the measurement optical system is aimed and focused on the eye to be examined, the microcomputer 5 sends a measurement start signal to the measurement optical system. Then, based on the image information from the optical measurement unit l and the image signal from the image recognition device 3, the microcomputer 5
The eye refractive power is calculated. In addition, 6 in the figure is an operation switch for the microcomputer 5,
7 is a printer that prints and outputs the results calculated by the microcomputer 5. The optical measurement part l and the main body part 2 are connected by a cable (
(see Fig. 20) or by radio.In any case, only the optical measuring section 1, which is the part that requires position adjustment with respect to the eye to be examined, is taken out during measurement.
It is movably separated from the stationary main body 2 as its movement system, and therefore it is extremely easy for the examiner to hold it in his hand and perform position adjustment operations with respect to the eye to be examined. FIG. 2 shows the measuring optical system 8 built into the optical measuring section l in this embodiment, and FIGS. 3 to 8 show the measuring optical system 8 as each element optical system constituting the measuring optical system 8. Each of the elemental optical systems of the optical system 9, the measurement light receiving optical system 10, the target optical system 11, the camera optical system 12 for monitoring, and the reticle optical system 13 for monitoring, and the illumination optical system 14 for monitoring, respectively. are represented separately. First, FIG. 3 shows the measurement light projecting optical system 9. An infrared light source is used as the light source 15 for projecting the measurement light, and the light source 1
The measurement light projected from 5 is reflected upward at right angles by the first reflecting mirror 16. Above the optical axis a of the measurement light reflected to one side of this right angle, there is a first reflecting mirror 1 that forms each right-angled opposite side of the two right angle prisms with respect to the optical axis a1.
A first prism 17 is disposed on the opposite side of the prism 6 and is joined at an angle of 45°. This first prism 17 is a half prism, which partially reflects infrared light at a certain ratio and transmits the rest, and transmits most of visible light. Therefore, by positioning the eye E on the optical axis a1 of the measurement light refracted at right angles by the first prism 17,
The measurement light can be projected into the eye E to be examined. Note that the optical axis a + J between the light source 15 and the first reflecting mirror 16:
In order from the light source 15 side, there is one collimator lens, a light projection pattern mask 20. A light projection relay lens 21 is arranged, and an eyepiece lens 22 is arranged on the optical axis a1 between the first reflection mirror 16 and the first prism 17. The measurement light is projected from a light projection source 15 and passed through a collimator lens 19 . Light projection pattern mask 20. Light projection relay lens 21. First reflective mirror 16. The eyepiece lens 22, the first prism 17, and the corneal surface to the pupil. The light source enters the eye E through the crystalline lens and projects a light source pattern onto the retina. FIG. 4 shows a light receiving optical system 10 for measuring light. The measurement light of the light receiving system becomes reflected light from the image of the light beam (light projection pattern) formed on the retina of the eye E to be examined, and travels backward along the optical axis a1 of the light projection optical system 9. , first reflecting mirror 16 (second
When the mirror 16 reaches the position (shown in the figure), it passes through the first through hole 23 opened approximately at the center of the mirror 16. A diaphragm 24 is formed directly below the first through hole 23, and a second reflecting mirror 25 (shown in FIG. 2), which will be described later, is directly below the diaphragm 24.
A second through hole 26 is formed approximately in the center of the diaphragm, and the measurement light that has passed through the first through hole 23 further passes through the diaphragm 24 and the second through hole 26 and travels straight. Therefore, the first through hole 23 for the light-receiving system measurement light traveling in the opposite direction along the optical axis a.
After passing, the optical axis a continues straight downward and reaches the light receiving sensor 29 via the imaging lens 27 and the filter 28. The aperture 24 is arranged with respect to the eyepiece 22 at a position that is substantially conjugate with the corneal position of the eye to be examined, so that the eye to be examined is free from measurement errors caused by slight misalignment errors of the optical axis of the measurement optical system with respect to the optical axis. is automatically corrected. Therefore, it is possible to minimize measurement errors caused by camera shake, that is, misalignment between the optical axis of the eye to be examined and the optical axis of the measuring optical system, which tends to occur when the hand-held optical measuring section 1 is employed. A detailed explanation of this principle will be given later. FIG. 5 shows the monitor illumination optical system 14, which evenly surrounds the optical axis a3 of the monitor illumination optical system and faces the subject's eye located on the optical axis a5 when aimed. 6 infrared light sources or illumination light sources 30 are arranged. Note that this forward axis a3 coincides with the optical axis a4 of the measurement light. Since this illumination is based on infrared rays, the eye E to be examined has no sensation of light and does not feel dazzling. The illumination light from the above-mentioned illumination optical system 14 is reflected by the cornea of the eye E to be examined, and this reflected light is used as aiming light for aiming the optical measuring section 1 toward the eye E to be examined, and the monitoring camera optical system 12 is used as the aiming light for the eye E to be examined. Configure as shown. As shown in FIGS. 9 and 10, this illumination light is projected so that a parallel ray (beam) forming an appropriate inclination angle λ with respect to the optical axis a3 of the illumination optical system is directed toward the eye E. In this case, if the optical axis aE of the eye E is shifted from the optical axis a of the illumination optical system, six images (approximately point light sources) are created by the corneal reflected light (aiming light) of the six beams The center position of the circle (that is, the optical axis aE of the eye E to be examined) formed by the image (which appears as a reflected image of Aiming can be performed by measuring the amount ε and setting it to 0. Further, the corneal reflection bright spot of the illumination light source 30 is more than three times stronger than other video signals, and it is also possible to use this to detect the in-focus state. In other words, when focusing, this bright spot is the smallest and the contrast is strongest, so this state can be detected by the image recognition device 3. Similar to the aiming operation, this bright spot can be detected by focusing on the same object, the corneal reflection bright spot. Therefore, both aiming and focusing operations can be detected at a relatively high speed and can be processed immediately. By aligning the sights in this way, the optical axis of the measuring system, monitor system, etc. can be aligned with the optical axis aE of the eye E to be measured. The distance between the measurement unit 1 and the eye E to be examined, and furthermore the distance between the eyepiece lens 22 of the measurement light projecting optical system 9 and the corneal surface of the eye E to be examined, can be set to a constant distance suitable for measurement. Behind the first prism 17 (partially transmitting infrared light) on the optical axis a3 of the illumination optical system 14 (with the illumination direction being the front), there is a guichroic mirror 31 that reflects infrared light and transmits visible light. is arranged at an angle of 45° with respect to the optical axis a3 so as to reflect the aiming light (infrared rays) downward at right angles. The second prism 17 is a half prism with characteristics almost opposite to those of the first prism 17, that is, it is a half prism that transmits most of the infrared light and reflects most of the visible light.
A prism 32 is arranged. The aiming light reflected by the guichroic mirror 31 passes through the second prism 32 and travels straight downward along the second prism 32.
The light passes through a monitor relay lens 33 located below the lens and enters a third reflecting mirror 34 located below the monitor relay lens 33 . The aiming light is further reflected at right angles and reaches the second reflection mirror 25. Since the optical axis a intersects with the optical axis a of the measurement light receiving system 10 on the plane of the second reflecting mirror 25, it intersects within the second through hole 26 to be more precise. Aiming light is second
It is further reflected downward at a right angle by the reflecting mirror 25, and the optical axis a
8 to the light receiving sensor 29. FIG. 7 shows the monitoring reticle optical system 13. On the side of the second prism 32, a reticle light source 35.
Reticle pattern mask 36. Reticle objective lens 37
are provided in order, and the light irradiated from the reticle light source 35 passes through the reticle pattern mask 36 along the optical axis a4.
becomes the marker pattern light, and further passes through the reticle objective lens 37 to the second prism 3.
2 and is refracted downward at a right angle. The reticle pattern is represented by, for example, two concentric circles, the inner circle of which indicates the minimum measurable pupil diameter, and the outer circle drawn at the standard position where the corneal reflection image occurs. The prism surface of the second prism 32 is arranged so that the optical axis a4 of the reticle light refracted downward at right angles by the second prism 32 coincides with the optical axis of the aiming light. Therefore, the subsequent optical system is the same as the monitoring camera optical system 12. In this way, since the optical system of the aiming light after the second prism 32 and the optical system of the reticle light match, if the centers of the corneal reflected lights of the six illumination lights are on the optical axis a3 of the illumination optical system, , and the center of the mark pattern on the reticle coincides with each other, and if this coincidence is detected on one light receiving sensor 29, it is detected that the aim is correct. In this embodiment, the reticle pattern is obtained by the reticle light source 35 and the reticle pattern mask 36, but the reticle pattern only needs to be able to display the position as the aiming reference on the monitor image. Alternatively, with respect to the monitor relay lens 33 on the monitor camera optical system 12, for example, a transparent glass plate that transmits infrared light may be placed at a position conjugate to the test object IIINF, and a pattern may be written on it. It is also possible to have the pattern detected on the light receiving sensor 29. In FIG. 8, the target optical system 11 is shown. ”-Note 1
Since the guichroic mirror 31 disposed on the optical axis a3-1 that has passed through the prism 17 transmits visible light, it is positioned behind the guichroic mirror 31 on the extension of the optical axis a5 to serve as a visual target. When an object 38 (see FIG. 20) is placed, the subject can see the object 38 through the first prism 17 and the glaucroic mirror 31, and while looking directly at this target, the subject's eye E is exposed to light. Axis aF is approximately optical axis a
, match above. As described above, the illumination light source 30 also serves as a light source for aiming light, and the light receiving sensor 29 is configured to detect aiming light and measurement light including the reticle tip. As a whole, the measurement optical system 8 itself is miniaturized, and is extremely advantageous in configuring the optical measurement section 1 as a no-day type. Further, the illumination light source 30 is connected to an optometry window 39 as shown in FIG.
A disk member 40 that is freely rotatable around the optical axis a is installed at the periphery of the optometry window 39 in the nose (not shown) of the optical measurement section l. Ori,
An illumination light source 30 is fixed to this disk member 40. This disc member 40 contains water! A weight 43 is attached to a position such that the two illumination light sources 30 are located on a fixed reference meridian 42, so that the disc member 40 and the illumination light source 30 are always aligned regardless of the inclination of the optical measuring section l. Able to maintain a certain posture. Although such a structure may cause undesirable "shaking" in the illumination light source 30, since the aiming operation is originally performed carefully and quietly, there is no problem in reality. The microcomputer 5 built into the main body 2 controls the illumination light sources separately from the pair of illumination light sources on the reference meridian 42 or other illumination light sources. When the attitude of the optical measurement unit 1 is tilted with respect to the horizontal direction, the image recognition device 3 determines the coordinates of a pair of corneal reflection bright spots on the monitor corresponding to a pair of illumination light sources on the reference meridian 42. Therefore, in order to know which bright point pair is horizontal (based on the horizontal), control is used to turn on only one pair of illumination light sources along the reference axis and turn off the other illumination light sources. (The reverse control is also performed.) This control operation only takes a moment, and the examiner does not have to worry about unsightliness such as darkening of the monitor screen.In this way, the horizontal Since the inclination angle of the optical measurement unit 1 can be obtained with respect to the axis angle (A
Correction is made by subtracting only that angle from the value of XIS), and the correct value is output and displayed. Various patterns are possible for the projection pattern mask 20 of the measurement light projection optical system 9. For example, a circular pattern formed in an annular shape around the optical axis a1 and having a predetermined radius, or similar to this circular pattern, the optical axis a
, a spot pattern arranged at equal central angular positions, such as every 90 degrees, every 60 degrees, or every 45 degrees, is realistic. Incidentally, in this embodiment, a spot pattern of 90° f6 is adopted. In the eye refractive power measurement apparatus of this embodiment configured as described above, the eye refractive power is measured by the i'1J11 constant light projection/reception optical system 9.10 as follows. FIG. 12 is a perspective view showing the optical path of the measurement light, that is, the spot light, which passes through a fixed point O on the optical axis a1, enters the cornea E, and reaches the retina E and above in this embodiment. still,
FIG. 12 shows only the optical path of one spot light as a representative. In the measurement light projecting optical system 9, which is aimed and in focus, its leading axis a1 coincides with the optical axis a6 of the eye to be examined on the Z axis in the figure, and the measurement light is projected onto the optical axis a5. The light passes through a fixed point O, enters a point P on the cornea E1, and reaches a point Q on the retina E. Note that this fixed point ○ is the measurement light receiving optical system 1.
When the eyepiece lens 22 is located at a position where the position of the aperture 24 and the position of the corneal surface are conjugate with each other at
This is a point that passes on the optical axis a1 after passing. Now, the distance between the retina E and the cornea E on the optical axis aE is d
1. Let dl be the distance between the cornea and the fixed point ○. The distance from the optical axis aE to the point P on the cornea E1 is h l
Let the inclination of the direction from the optical axis aE to the point P with respect to the rX-axis direction be θ. Further, it is assumed that there is a major axis F1 of an ellipse representing the refractive power of the eye to be examined in a direction inclined by φ with respect to the X-axis. The short axis F is perpendicular to the long axis F1. If the component in the major axis direction of this point P is P FI + the component in the minor axis direction is pFy, then P p + = h + cos (θ - φ) (1) P Ft = h +
It can be expressed as 5in(θ-φ)(2). Similarly, regarding the image (point Q) projected onto the retina after receiving refractive power from this corneal surface, the long axis F1 direction and the short axis F at the distance from the optical axis al:, and each component in the force direction QFl+QF
! is, Q,,=11-d(=-)l・P FI(3)f,
d. It can be expressed as It is the corneal refractive power in the direction. If the horizontal eye refractive power D1 is the vertical eye refractive power D2, then the following holds true. On the other hand, if the image of the light projection pattern projected onto the retina is viewed from the measurement light receiving optical system 10, as shown in FIG. 21 (FIG. 21 is shown in a simplified plan view), the eyepiece A diaphragm 2 located at a position conjugate with the cornea E1 with respect to 22
4, only the light beam near the optical axis of the light receiving system passes through this aperture 24 and is guided to the imaging lens 27. Also,
The position of the diaphragm 24 is also the focal point of the imaging lens 27, and the image light that passes through the diaphragm 24 and enters the imaging lens 27 travels approximately parallel to the optical axis and is reflected onto the light receiving sensor 29. From the shaft. The image is formed at a distance of . That is, in the light receiving system, an image is formed on the retina E at a distance h from the optical axis, and an image similar to this image is formed on the light receiving sensor 29 from the optical axis. formed at a distance of Here, the inclination of the direction from the optical axis to point Q with respect to the X-axis direction is defined as ψ. In addition, as assumed in the light receiving system, the long axis F of the refractive power of the subject's eye is in a direction inclined by φ with respect to the X axis, and the short axis F
, is perpendicular to the long axis F. The relationship between h and ho is expressed by equation (9). However, L is a constant determined by the focal length and arrangement of the eyepiece lens 22 and the imaging lens 27. Based on the above assumptions, Q FI and Q F in the light receiving system. is expressed by equations (10) and (11), and by substituting the relationship in equation (9) into each of these equations, we get (12), (13)
Expressed by the formula. Q++=hcos(ψ−φ) (
10) Qrt = hsi mouth (ψ-φ)
(11) Here, equation (7) and (12)
From equations (8) and (13), equations (14) and (
The relationship of formula I5) is established. Perform operations such as shifting and expansion in equations (14) and (15) to obtain hocosφ= S X, hosinφ=
When the coordinates (S X, S y) of the spot light projected onto the sensor 29 are determined as
7) Equation is obtained. X y In formulas (16) and (17), Lh, (1/d
, -D, ) = A. When replaced with I5・hl(l/d, -D2)-B, S
x-=A cos(0-φ)cosφ-Bsin(0
−φ) sinφ−(1g) S y= A C05(θ−φ) sinφ+Bs1n(
It is simply expressed as θ−φ)cosφ. In equations (18) and (19), the unknown to be measured is Δ
. B, φ, and two values θ1. SXl for θ2 respectively
+s Y l+ S X21 These unknowns can be theoretically determined from the four equations giving S y2. In general, the correction value for refractive error is spherical power (SP
I+), cylindrical power (CYl,,), axis angle (AXIS)
or 5PII-=D 2. CYL=D
1- D 2+ AXIS-φ, respectively. In this example, as shown in FIG. 13, the light projection pattern is on the water meridian and the vertical meridian on the cornea passing through the optical axis aE of the eye E to be examined, facing each other across the optical axes dl, a, and H. This becomes a 4-point spot pattern. These four points, or four spots, are image P. + P IJI P 18+ P 27 is shown in the figure. Now, the 1st generation spot image P. (i.e., in the case of θ1-00), the coordinates on the sensor 29 are S X + "SXo + S
y+□sy. and 17, for the spot image P (that is, when θ2=90'), the coordinates on the sensor 29 are S X, "SXs, S
Solving the above four equations as Yt”SYs, A=1/2(Sxo+5ys4f(SxoSye)'4
Syo'l] (20) B=1/2(Sxo+5ye-v
'1(Sxo-Sys)2+4Sy++''l:l
(21) can be obtained. Therefore, as shown in FIG. 13, two points P on the horizontal X-axis and the vertical y-axis -F are projected onto the cornea E, Im using the spot pattern. + Point S of the image formed on the light receiving sensor 29 as shown in FIG. 14, corresponding to the image of P9. +Ss coordinates (SXO2Syo) and (S
xs, 5ye) by the image recognition device 3, it is possible to know the degree of refraction of the eye to be examined. In this embodiment, four spot destinations are used instead of two, and the reason will become clear from the description below. By the way, the distance from the optical axis of the spot of the light receiving sensor 291 is as follows. Although the detailed calculation formula for is not shown before, it is given by the following formula (see FIG. 21). However, d2 is the distance between the aperture 24 and the imaging lens 27. The above formula is for the case where the optical axis a of the measurement system and the optical axis ae & of the eye to be examined coincide, but in this example, the axis deviation between the two axes and the paraxial theory can be applied. Even if this occurs, the above equation (23) can be applied. In other words, even if equation (23) is applied to 6 in this case, no measurement error occurs. One of the reasons for this is that, as described above, the sufficiently small aperture 24 is arranged at a position where the cornea E1 is approximately conjugate to the eyepiece 22. The reason is detailed below. Now, in FIG. 22 showing the measurement light projection system, it is assumed that the measurement system optical axis a1 and the subject's eye tip axes aE and E are misaligned by an angular deviation, δ (radian), and a parallel deviation, ΔX. . In this case, the position or height h of the spot image generated on or on the retina a is expressed by the following equation. On the other hand, in this case, the measurement light receiving optical system is as shown in FIG. In FIG. 23, a state in which a spot image having a certain area is received on the sensor 29 is exaggerated. Now, in FIG. 23, there is no aperture 24 or the aperture 24"
Even if there is, if the aperture diameter is large, the spot image received on the sensor 29 will be relatively large. In this case, if you want to find the center of gravity of the spot image,
Since this becomes the projection point of light passing through the center of the pupil of the cornea, the distance hoc of the center of gravity C1 of the spot image from the optical axis 212 of the light receiving system no longer corresponds accurately to the value of the point Q on the retina E1. That is, if we substitute equation (24) into equation (25), we get. That is, this equation (26) is an axis deviation error amount, where d represents the distance between the imaging lens 27 and the light receiving sensor 29. The focal length of the eyepiece is a, and the distance between the eyepiece 22 and the cornea E1 and the eyepiece 2
The distance between the diaphragm 2 and the aperture 24 is l:l. On the other hand, as shown in FIG. 23, if a diaphragm 24 with a sufficiently small aperture hole is provided above the optical axis a of the light receiving system, some of the reflected light from the spot image on the retina E will be reflected from the optical axis a of the measuring optical system. Only a very small beam of light passing through the point where E1 intersects the cornea E1 can be selectively extracted onto the sensor 29. Let this sufficiently small spot image received on the sensor 29 be S, and the distance of its center of gravity C7 from the measurement system optical system is defined as S. Then, the following formula holds true. Here, substituting equation (23) into equation (27) yields. In other words, equation (28) does not include the amount of axis deviation error, and is the same as equation (23). In other words, even if an axis misalignment occurs between the optical axis of the subject's eye and the optical axis of the measurement system when the measurement light is projected, it will not adversely affect the measurement value, and this will ensure accurate measurement. Become. The solution described below (modification example) for the above solution
Also, it is possible to correct measurement errors that may occur due to optical axis misalignment between the optical axis of the measurement system and the optical axis of the eye to be examined. That is, in this embodiment, two pairs of spot lights are used as measurement lights, and the two spot lights of each pair are arranged at point-symmetrical positions with respect to the optical axis of the measurement system. FIG. 24 shows a pair of measurement beam projection systems when optical axis misalignment occurs. In FIG. 24, each spot light corresponds to each point P on the square network E1.
, P' and is projected to points Q and Q' on the retina E. The distances of each point P and P' from the optical axis a of the measurement system optical system are the same value (hl) and are located at symmetrical positions with respect to the optical axis a2. In other words, point P is at the position of point P beam. is at the -h1 position. Each point Q, Q' on the retina E1 is located at a position h' with respect to the optical axis of the eye to be examined. At this time, the following equation holds true. h1+△x h. h=h, +△x−d(−−−−δ), (29) “
d ho・−h1+△x−d(±Yanjiku−j+δ) (30)
d A measurement light receiving system in this modification is shown in FIG. This measurement light receiving system is not provided with an aperture. Now, the respective reflected lights of the two spot images formed on the points Q and Q' on the retina are transmitted to the retina E1, the eyepiece 22. Imaging lens 2
Suppose that a spot ('IS. ,
A light flux passing through the center of the pupil of the cornea E1 of the eye to be examined is illustrated, and this case will be discussed. In this case, the luminous flux corresponds to each center of gravity of the spot images S, S''.6 Now, here is the position or height of the center of gravity of the spot images S, S'' from the optical axis. +ho'', the following equation is obtained. Next, add equation (29) to equation (31), and add equation (30) to equation (32).
), the following equation holds true. Here, if we consider that the spot images s and s' on the sensor 29 correspond to the Q point or Q' point shown in FIG. 24 showing the measurement light projection system, they correspond to the distance. The distance or height on the sensor 29 that should be determined. It can be seen that is given by the following equation. Therefore, by substituting equations (33) and (34) into equation (35), the following equation can be obtained. The above equation (36) does not include the axis deviations mΔX and δ. That is, it is possible to automatically obtain a measured value with the amount of axis deviation corrected. In the above description, one pair of measurement lights has been described, but the height ho can be similarly determined for the other pair of measurement lights. As mentioned above, this variation uses paired measuring beams to measure the height of each spot image. ′ and h o ”, and calculate the height according to equation (35). Two solutions were shown above as a countermeasure for correcting optical axis misalignment, but in reality, these two solutions are It is better to use a combination of countermeasures.In other words, in the first solution, either an aperture with sufficiently small aperture holes is used, or in reality, it is of course impossible to make the aperture hole O. The spot image received on the sensor 29 is smaller, the smaller the spot image is, the smaller the spot image received on the sensor 29, the smaller the spot image received on the sensor 29.
Although this center of gravity can be determined accurately, it can be said that as the spot image becomes larger, the accuracy of calculating the center of gravity position becomes worse. On the other hand, in the second solution, since no diaphragm is provided, the spot image received on the sensor 29 is quite large, and this results in the need for a sensor with a very large receiving surface, which requires a large amount of equipment. There is a problem in that it hinders miniaturization. Above, No. 1. In order to eliminate the disadvantages of the second solution, the size of the aperture hole of the diaphragm 24 in the first solution should be adjusted so that the light flux of the device necessary for the light receiving sensor 29 and the minimum amount passes through the second solution. All you have to do is implement the above solutions at the same time. This embodiment adopts this third solution. FIG. 26 shows a measuring light receiving system adopting this solution. In addition, in FIG. 26, a light ray passing through the upper edge of the diaphragm hole of the diaphragm 24 is shown for ease of viewing. Moreover, FIG. 26 is a diagram similar to FIG. 25 except that a diaphragm 24' is provided and the reflected light of the spot light is exaggerated as a bundle of light. Further, the value of the large radius of the aperture 24' is y. Now, if measurement light is projected by the measurement light projection system shown in FIG. 24, the following equation holds for one of the measurement lights. As described above, since equation (29) holds true, when this is substituted into equation (37), the following equation holds true. Similarly, the following equation also holds true for a measurement beam that is optically axially symmetrical with the measurement beam described above. As mentioned above, from equation (30), the following holds true, so by substituting this into equation (38), the following equation holds. Here it is. bird. ``If we take the difference between the two and divide it by 2, we get (
As in the case of formula 35), it is possible to obtain a formula that does not include X and δ in the error amount. Note that equations (37) and (38) are general equations. Now y
If O, then the light ray passing through the center of the aperture hole will be considered, and the equations obtained in this case will be the same as equations (33) and (34). Above, we have explained how to correct errors in measured values when there is a misalignment between the optical axis of the measurement system and the optical axis of the subject's eye. (Amount of axis deviation within the range to which the paraxial theory can be applied). The amount of axis deviation is within this limit (△X・month mm or less, δ・±10
If the value exceeds (within '), the spot image on the light-receiving sensor will be distorted due to the effects of aberrations, etc., making correction impossible. In other words, even if correction is made in this case, the resulting calculated value lacks reliability. Therefore, in this case, it is preferable to perform error processing such that the calculated value is considered unreliable and is not adopted. This error processing will be explained in detail in the explanation of the flowchart shown in FIG. Hereinafter, FIG. 15 shows a measurement flowchart by the eye refraction measuring apparatus of this embodiment, and each step thereof will be explained in order. First, in step 100, as a preparation mode, the illumination light source 3
0 and the reticle light source 35 are turned on, and the measuring light projection light #15 is turned off, and the process moves to step 101. In the monitor image at this time, if the eye E to be examined is in front of the illumination light source 30, a group of bright spots and a reticle pattern due to the corneal reflected light of the illumination light will appear, and if the eye E to be examined is not present, only the reticle pattern will appear. appear. Incidentally, step 100 can also be interrupted by a timer according to step 100''. First, step 100' is a mode for periodically importing image information of the eye to be examined into the memory of the microcomputer 5 for the purpose of automatically monitoring the eye to be examined. For this purpose, a state is momentarily created in which only the illumination light source 30 is on, and the reticle light source 35 and the floodlight #, I5 are off.
If the eye to be examined exists in this state, its image is recorded, and the state of the eye to be examined at that time (the state of the corneal reflection bright spot group) is detected. Second, this step 100' is performed in order to periodically manage the state of the switch 6 that determines calculation and control conditions, etc. When the switch state is detected and there is a change in the switch input, the microcomputer 5 Update the contents of switch state storage memory. In step 101, it is determined whether the printer switch is on, and if it is on, step 101
In step 2, the data of the previous measurement stored in the microcomputer 5 is outputted to the printer 7, and then the process moves to step 103. If it is off, the process moves directly to step 103. In step 103, it is determined whether or not the eye E to be examined is in front of the illumination light 130. If there is, the process moves to step 104, but if not, the process returns to step loO, and the steps up to step 103 are repeated again. This determination can be made based on whether or not the corneal reflected light of the illumination light is detected by the light receiving sensor 29, and the examiner can also determine this on the monitor image. In step 104, as an aim detection mode, the image recognition device 3 determines the barycenter position of the bright spot group by the corneal reflected light of the illumination light, that is, the center X-axis and y-axis coordinates (X or y on) of the circle formed by the bright spot group. , the process moves to step 105. In step 105, the X coordinate (
It is determined whether or not the absolute value IX,l of X o) is smaller than the value of the y-axis deviation reference set as the allowable range of "deviation" in the X-axis direction, and if it is smaller, the process moves to step 106, If it is not smaller, the process returns to step 100 and the steps up to step 105 are repeated again. In step 106, the X coordinate (
It is determined whether the absolute value 1y01 of yo) is smaller than the value of the y-axis deviation standard set as the allowable range of "deviation" in the X-axis direction, and if it is small, the process moves to step 107, and if it is not small, Then, the process returns to step 100 and the steps up to step 106 are repeated again. In step 107, as a focus detection mode, a high frequency component (Hf) of an image signal of a group of bright spots caused by corneal reflected light of illumination light is detected.
is determined by the image recognition device 3, and the process moves to step 108. Note that this method of detecting the in-focus state by detecting high-frequency components is an example of a method that can be realized only by software, but in a more general way, it also includes methods using hardware. In step 108, the high frequency component (Hf) obtained in step 107 is set as the allowable range of the focused state.
It is determined whether or not the value is larger than the contrast reference value. If it is larger, the process moves to step 109; if it is not larger, the process returns to step 100 and the steps up to step 108 are repeated again. The aiming situation and focusing situation in steps 104 and 107 above appear on the monitor image in the form of positional deviation between the reticle pattern and the bright spot group and the strength and weakness of the contrast of the bright spot group, and the examiner can You can get an idea of how to adjust the aiming and focusing conditions. In step 109, as the angle correction mode, only the illumination light sources corresponding to the two bright spots on the reference meridian 42 are turned on among the bright spot group due to the angle and film thickness incident light of the illumination light, and the other illumination light sources and measurement light are turned on. The light source I5 and the reticle light source 35 are turned off, and the process proceeds to step 110 by manually controlling the monitor image. In step 110, a straight line connecting the two bright spots shown on the monitor image in step 109 and a horizontal reference line (
(corresponding to the horizontal axis of the optical measuring section 1) is detected, and the process moves to step 111. In step 111, the illumination light source 30 and reticle light source 35 are turned off as the measurement mode, and the light source 15 for projecting measurement light is turned on! The tuft is input into the monitor image and the process moves to step 112. At this time, on the monitor, the image of the fundus pattern detected by the light receiving sensor 29 by the measurement light receiving optical system 10 appears for a moment as an image, or the measurement is completed at this point, so each light source is Immediately, the process moves to step 112, where the measurement light source 15 is turned off and the illumination light source 30 and reticle light source 35 are placed in the same state as the preparation mode in which they are turned on. Step 112 moves to step 113, in which the light receiving optical system 10 of the measurement light in the measurement mode
It is determined whether the height of the No. 3 level input to the light receiving sensor 29 is sufficient. This is the image signal of the eye to be examined 1;' or, in the case of cataract, the image signal of the level necessary for measurement. In some cases, the signal level cannot be obtained, so a check is performed in this step.If the signal level is high enough in step 113, the process moves to step 114 and enters calculation mode, and if the signal level is insufficient, it is checked. In this case, the process moves to step 120 and error processing is performed.The error processing at step 120 is as follows.
For example, a display such as "°'no target'" may be displayed on the monitor screen in step +16, which will be described later.In step 114, the measurement data is input into an arithmetic expression stored in advance in the microcomputer 5, and based on this, the eyeglass lens Or each element of a contact lens, spherical power (SPH), cylindrical power (CYl, ), axis ff + power (A
XIS) is calculated. The calculation formula for each element may not be uniform because the measurement points differ depending on the light projection pattern, but in this example, the total of 4. [It is designed to project the sun bont pattern, and as shown in Figure 4, each spot y+-3°+S91 S fill S2
7's X coordinate and y coordinate S Q (SXO, 5yo), S
9(SXg, 5y9)S +e(Sx+a, Sy
+e) and S +7 (Sx+7.5yt7) are respectively determined, and the spherical power (SPII), cylindrical power (CYL), and axial angle (AXIS) are determined by the following calculations. sx+ SXo SX+8 SX, -8X'"-3x" sy 5y-Sy... s ,, -Sy t"-8y□ A-↓(S x++S yt+(((S K1-3 y
2)'+4B-±C8x++s yt-(f(S xr
-8yz)'+4Sy+'1) Sy+'l) SPII=D, == +-・B d, L-h. CYL=D, -D, -Sat(B-A)-h" When the second calculation is completed, the process moves to step 115. In this embodiment, step 114 will be described in detail as follows.
A process similar to the subroutine shown in Fig. 15 (part 3) is performed, and the optical axis of the measurement optical system and the optical axis of the eye to be examined are If an axis misalignment occurs between the two, it is possible to treat the obtained data as unreliable and treat it as an error. In other words, in this eye refractometer, camera shake is likely to occur due to the use of the hand-held optical measuring section 1.According to the subroutine processing shown in FIG. 15 (part 3), , it is possible to check this camera shake. This subroutine will be explained with reference to FIG. 15 (part 3) and FIG. 27A. FIG. 27Δ shows four spots S as a result of misalignment between the measurement system optical axis a and the subject's eye optical axis between the time of aiming and focusing and the time of projecting the measurement light. + S 9+ S fill S
27 coordinates are shown. First, in step 114a, each spot image S. ,S. SIB+S2? The center of gravity coordinates S o (Sxo, 5
yo), S 5 (SX7.5ya). S +8 (SK+e, Sy+s), S z□ (sX
, t+S>'z7). Next, in step 114b, two pairs of spots S are placed in a point-symmetrical positional relationship. + 318: S 9 + S 2? Find the midpoint coordinates for each. That is, the spot image S
. The coordinates (Mx, , My
l) and (MX2°My2) can be calculated using the following formula. Mx, = Sxo + Sx□. MX, = SX □ + 5
Distance ME between yl) and M y (Mxt+ Myz)
(= l M5M21 ) is calculated using the following formula. ME=(((Mx+-Mxt)2+ (Myl-My*
)'1 distance ME is O when the optical axis of the measurement light optical system and the optical axis of the eye to be examined coincide, and increases as the amount of deviation between the two axes increases. If the amount of deviation between the two axes becomes large, the resulting measurements will be unreliable. In this embodiment, "3 diopters" is adopted as the quasi-value for determining the reliability of the measured value y, and in step 114d, the distance M
If E or 3 diopters is one or more, step 114
The process proceeds to step 114e, where error handling is performed, and the process proceeds to step 116. For example, "try" is an example of error handling.
Again” etc. may be displayed on the monitor screen in step 116, which will be described later.In step 114d, the distance M
If E is less than 3 diptories, the measurement is considered reliable and the process proceeds to step 114f. Step 114: Now, the spherical power (SPH), cylindrical power (cyt. We have shown an example of a method for detecting the amount of deviation between the optical axis and the optical axis of the subject's eye, but in the end this only applies to the four sub-spots 7)
Although the amount of deviation is detected based on the relative positional relationship of the image with respect to the optical axis of the measurement light receiving optical system, this relative positional relationship can also be determined by other methods. The subroutine in this case is shown in FIG. 15 (part 4). FIG. 27B, which explains this subroutine according to FIG. 15 (part 4) and FIG. 27B, is a diagram similar to FIG. 27A. First, in step lla, each spot image S is created. +89+S1
8+S2? The centroid coordinates of S o (SXo, 5yo), S
e(Sxs, 5ya), S+a(Sx+e, Sy
+a), S t7 (Sxt7.S)'t7). Next, in step 114h, each spot image S on the X axis. and S18, the difference in distance △t from the respective origin 0
Each spot image S on the lxSY axis. Difference in distance between each spot image S9 and St7 with respect to the origin 0 on the X axis, ΔVx, Spot image S on the Y axis and S, ? The difference in distance Δvy from the origin to the respective origin is determined by the following equation. △Hx=Sxo + SX+e △Hy=Syo 10 Sy+a △Vx=Sxs + 5xt7 △Vy=Sye + 5yt7 Next, in each step 114i, 114j, l14, each difference △HX, △fly, △Vx, △ vy
are compared with 3 days of trees, which is a reference value. If the difference is not greater than the reference value at each step, step 1
Proceed in the order of 14i to 1141, and then proceed to step 114■
Proceed to step ll4m. On the other hand, each stage, pu 114
If i=l141 and the difference is greater than the reference value, step 114
The process advances to step 114n, where error processing is performed. Step 114m is the same as step 114 described above. As a further detection method, the distance between the spot images S. Sx27
+5y27) or by comparing the distance between spots S Q(SXO,5yo) and 327(SX2.+
5YtJ distance and spot image S5(SXs, 5y
s) and the distance between S l1l (SXIII, SY+s>), it is possible to determine the amount of deviation between the two axes. Now, returning to step 115 for explanation, step +
15, each element SPH obtained in step 114; It is determined whether the values of CYL and AXIS are within a reasonable numerical range. If they are within a reasonable range, the process proceeds to the next appropriate step 116, and if outside the reasonable range, the process proceeds to step 121. error handling is performed. As for the error handling at step 121, as described above, "
"try again" etc. will be displayed in step 116, which will be described later.
All you have to do is display it on the monitor screen. In step 116, the calculation result in step 114 or the error processing result in step 120 or 121 is displayed on the monitor screen. Note that this step 116
As the output condition for displaying the calculation results in [IN], it is possible to switch the display between mirror lens and contact lens, and how finely the calculation results should be displayed for the song. It is also possible to set the display stage (STEP value). These operations are performed in step 100 by operating switches. Through this operation, the intended processing method is manually input to the microcomputer 5. It is also possible to set the distance between the spectacle lens and the cornea (O in the case of a VD value contact lens). When step 116 is completed, the process returns to step 100, the preparation mode. Furthermore, the examples shown in FIGS. 2 to 8 as measurement optical systems are only one embodiment of the present invention, and various modifications may be made from this embodiment in order to configure the optical measurement section into a handy type. It is possible for a person skilled in the art to do so, and FIGS. 16 to 19 show a modified example of a four-point spot pattern. FIG. 16 shows the measuring optical system 8', FIG. 17 shows the measuring light projecting optical system, FIG. 18 shows the measuring light receiving optical system 10', and FIG. 19 shows the aiming optical system 50. The measuring light projection optical system 9' uses a half mirror 45 instead of a half prism, and runs along a straight optical axis a1' from the infrared light emitting diode projection light source 1b'' to the half mirror 45. By positioning the eye E° to be examined on the optical axis 81'' of the measurement light reflected at right angles at 45, the measurement light can be projected into the eye E'. Optical axis a1 between light source 15' and half mirror 45
° Above, collimator lenses 19 are arranged in order from the light source 15' side.
, pyramid-shaped four-sided pyramidal prism 46□diaphragm 47.
2-hole floodlight relay lens, 4-hole mirror 48. Eyepiece lens 2
2゛ is placed. The four-sided pyramidal prism 46 transmits infrared light from the light source 15° through the collimator lens 19' into four beams that pass through positions at central angles of 90' around the optical axis a,'' in order to form a four-point spot pattern. The aperture 47 is placed at the focal point of the light emitting relay lens 21', and the four light beams emitted from the J9.4 pyramidal prism 46 pass through the aperture 47 and then go to the light emitting relay lens 21'. The four-hole mirror 48 directs the measuring light, which is the retinal reflected light in the measuring light receiving optical system 10', which will be described later, at right angles. A mirror for reflection, whose upper reflective surface is inclined at 45 degrees with respect to the optical axis, +.
In the projection optical system 9', a small hole is formed in a portion corresponding to the optical path of the projection spot pattern so as not to block the optical path of the projection spot pattern. Therefore, the measurement light that has passed through each of the four-hole mirrors 48 becomes a four-point spot pattern and enters the eyepiece 22', is reflected at right angles by the half mirror 45, and enters the subject's eye E'. In the measuring light receiving optical system 10', the measuring light travels backward along the optical path of the light emitting optical system 9' from the eye E" to the four-hole mirror 48, and
It is reflected at right angles by the hole mirror 48. A micromirror 49 having a reflective surface parallel to the four-hole mirror 48 is arranged on the optical axis of this reflected light.
The micromirror 49 reflects the measurement light further downward at a right angle. The light I is below the micro mirror 49.
An imaging lens 27' and a light receiving sensor 29' are arranged along TIIIa2''. In the aiming optical system 50, the corneal reflected light of the illumination light partially transmitted through the half mirror 45 is reflected by the tychroic ink mirror 31'.
is reflected downward at a right angle by the monitor relay lens 33.
Pass through ゛. A first 45° mirror 51 is arranged below the monitor relay lens 33', and a transparent glass reticle plate 5 on which a reticle pattern is written on the reflected optical path.
2 is placed. This reticle plate 52 is arranged at a position conjugate with the subject's eye E'' with respect to the monitor relay lens 33'.A second 45° mirror 53 is located at a position passing through the reticle plate 52 from the first 45° mirror 51. is arranged so as to reflect the aiming light incident thereon downward at a right angle.Below the second 45° mirror 53 is a micromirror 49 in the measurement light receiving optical system 10°.
The following optical axis a3+ is shared with this light receiving system 10",
They also share an imaging lens 27° and a light receiving sensor 29°. Therefore, this aiming optical system 50 is configured such that a monitoring reticle optical system is incorporated into a monitoring camera optical system. Note that in the aiming optical system 50, the micromirror 49 is extremely small and the aiming light passes through its periphery, so its presence does not pose a problem. According to the configuration and operation of the embodiments and modified embodiments described above, for example, as shown in FIG. 1 in one hand and position it toward the subject's eye, with the subject looking at the optotype 38 3 to 5 shoulders ahead, and observing the posture and position of the optical measurement unit 1 while looking at the monitor 4. If the aim and focus are achieved while making fine adjustments, the examiner only needs to capture that moment, and the rest is automatically calculated in the main unit 2, and the eye refraction is calculated. displayed on monitor 4. Therefore, the measurement time is extremely shortened, and since the optical measurement unit 1 can be adjusted to any posture of the subject, it is easy for the examiner to perform the measurement, and it is easy for the examinee to It frees people from the cramped and painful feeling during measurement.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an eye refraction measuring device according to an embodiment of the present invention. FIG. 2 is a diagram showing a measuring optical system built into the optical measuring section in FIG. 1. 3 to 8 are diagrams showing each optical system as each element constituting the measurement optical system, FIG. 3 is a measurement light projecting optical system, FIG. 4 is a measurement light receiving optical system, FIG. 5 shows an illumination optical system, FIGS. 6 and 7 show a monitoring camera optical system and a monitoring reticle optical system as aiming optical systems, and FIG. 8 shows a target optical system. Figure 9 and 1
Figure 0 is an explanatory diagram illustrating the aiming situation of the corneal reflected light due to the difference in the position of the illumination light source. Figure 9 shows a state where the aim is off, and Figure 10 shows a state where the aim is correct. . FIG. 11 is a diagram showing a state in which the illumination light source and weight are attached to a disk member. FIG. 12 is a perspective view showing the optical path of the measurement light in the measurement light projecting optical system, which passes through a fixed point on the optical axis, enters the cornea, and reaches the retina. FIG. 13 is a diagram generalizing the position of the measurement light pattern projected onto the cornea in this example on a coordinate plane, and FIG. 4 shows the measurement light pattern projected onto the cornea as shown in FIG. The position of an image on a light receiving sensor corresponding to a light pattern is generalized and shown on a coordinate plane. 1st
FIG. 5 (Parts 1, 2, 3.4) is a flowchart showing the control of the eye refraction measurement. 16 is a diagram showing a measurement optical system of a modified embodiment, FIG. 17 is a diagram showing a measurement light projecting optical system in FIG. 16, and FIG. 18 is a diagram showing a measurement light receiving optical system in FIG. 16. , FIG. 19 is a diagram showing the aiming optical system in FIG. 16. FIG. 20 is a diagram showing the measurement state of the eye refractive power according to this embodiment. Chapter 21.22
The figure is a diagram showing a measurement light receiving optical system and a measurement light projecting optical system for explaining a method of correcting an axis misalignment error between the measurement system optical axis and the subject's eye optical axis in the embodiments shown in FIGS. 1 to 15. . Second
FIG. 3 is a diagram for making FIG. 21 easier to understand. FIGS. 24 and 25 are diagrams showing a measuring light projecting optical system and a measuring light receiving optical system to illustrate another correction method compared to FIGS. 21 to 23. FIG. FIG. 26 is a diagram of a measurement light receiving optical system showing a case where both the correction method of FIGS. 21-22 and the correction method of FIG. 2425 are implemented simultaneously. FIGS. 27A and 27B are explanatory diagrams for error processing in the above embodiment, respectively. ■...Optical measuring section, 2... Main body, 3... Image recognition device, 4... Monitor, 5... Microcomputer, 8... Measurement optical system, 9... Measuring light floodlight optical system,
10...Measurement light receiving optical system, 11...Target optical system, 1
2... Monitoring camera optical system as part of the aiming optical system, 13... Monitoring reticle optical system as part of the aiming optical system, 14... Illumination optical system, 15... Measuring light 29... Light receiving sensor, 30... Illumination light source, 35... Reticle light source, 38... Visual target, E...
・Test eye 1 Figure 13 Figure 14 Figure 1/27 Figure 5 Figure 2 Figure 11 Figure 9 Figure 10 Figure 15 (f/) 2) Figure 15 (Part 3) Figure 20 f27A figure 278

Claims (1)

[Claims] (1) an optical measurement unit (1) equipped with a measurement optical system (8) for measuring the ocular refraction of the eye to be examined;
The measurement optical system (8) projects measurement light to form a projection pattern on the retina of the eye to be examined. A measurement light projection optical system (9) for projecting the measurement light and a measurement light reception optical system (10) for receiving the reflected light of the projection pattern image projected onto the retina of the eye to be examined; The light pattern is the measurement light projection optical system (9)
includes a total of four spot lights arranged around the optical axis (a_I) at intervals of 90° with respect to the optical axis, and four spot lights received by the measurement light receiving optical system (10).
Determine the amount of axial misalignment between the optical axis of the measurement light optical system (a_I) and the optical axis of the eye to be examined (a_E) when the measurement light is projected, based on the relative positional relationship of the two spot light images with respect to the optical axis of the measurement light receiving optical system. An eye refractive power measurement characterized by comprising a determination means for determining the axis deviation amount, a means for comparing the axis deviation amount with a reference value, and a means for processing as a measurement error when the deviation amount of both axes is equal to or greater than the reference value. Device.