JP3414792B2 - Eye refractive power measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eye-refractive-power measuring device, and more particularly to an eye-refractive-power measuring device capable of simultaneously measuring eye position abnormalities.

[0002]

2. Description of the Related Art The applicant of the present invention has proposed, in Japanese Patent Application No. 1-86107 (JP-A-2-264631), an eye-refractive-power measuring device capable of simultaneously measuring the eye-refractive power and the abnormal eye position.

This eye refractive power measuring device measures the eye refractive power from the gradient of the light amount distribution of the pupil image obtained by projecting a light beam on the fundus of the eye to be examined and blocking a part of the light beam reflected from the fundus. From the shape of the light intensity distribution, that is, the pupil diameter of the subject's eye is obtained by utilizing the fact that there is a rapid light intensity change at the boundary between the iris and the pupil, and the fact that a bright spot image of corneal reflection is obtained when measuring the light intensity distribution is used. However, the relationship between this bright point and the relative position of the pupil diameter makes it possible to measure the eye position abnormality and the line-of-sight direction.

[0004]

However, in the light amount distribution of the eye to be inspected obtained by the above-mentioned eye refractive power measuring device, there is an inclination as described above depending on the eye refractive power, so that the boundary between the iris and the pupil can be known. There is a problem that it is difficult. If this boundary cannot be accurately obtained, as shown in FIG. 4, the relative position between the pupil diameter and the bright spot is different due to the difference between the true pupil diameter d and the measured pupil diameter d ′. It is not possible to measure the line-of-sight direction. Furthermore, in order to measure the eye refractive power, the light emitting light source must be a surface emitting light source having a certain length, and as shown in FIG. 5, the bright spot image also has a certain area and shows one point. However, FIG. 5 shows a bright spot image 19 when the light source is a vertically long light source. Therefore, accurate eye position abnormality,
There is a problem that it may be difficult to measure the gaze direction.

In view of the above-mentioned circumstances, the present invention has made it possible to accurately measure the eye position abnormality and the line-of-sight direction.

[0006]

SUMMARY OF THE INVENTION The present invention comprises a measurement light source,
A projection system for projecting a measurement light source image onto the fundus of the eye to be inspected, a light receiving system for guiding the reflected light flux from the fundus of the eye to be detected onto a light receiving element arranged at a position substantially conjugate with the pupil of the eye to be inspected, and arranged in the light receiving system An edge-shaped light-shielding member that shields a part of the reflected light flux, and the eye refractive power of the eye to be inspected, the pupil diameter of the eye to be inspected, or the corneal reflection intensity from the pupil image of the eye to be inspected formed on the light receiving element. in the eye refractive power measurement apparatus for measuring the point image position, wherein the light-emitting area of the measurement light source is variable, it is measured, excluding the eye refractive power measurement relates to eye refractive power measurement apparatus for reducing the light emitting area, and before Symbol measured The present invention relates to an eye refractive power measuring device which has a plurality of light emitting parts, and which is turned on by selecting an appropriate part among the plurality of light emitting parts during eye refractive power measurement and pupil diameter measurement, and at least one light emitting part. Part of the light flux reflected from the fundus of the eye to be examined is blocked by the light blocking member, At least one light-emitting portion of which relates to eye refractive power measurement apparatus reflected light beam is not affected by shading or not blocked on the light blocking member from the fundus.

[0007]

[Function] When measuring the eye refractive power, the measurement light source is caused to emit light in a required light emitting area to obtain a light amount distribution necessary for the eye refractive power measurement. When measuring the corneal reflection bright spot image position, the light emitting area is reduced to reduce the cornea. The area of the reflected bright spot image is reduced to improve the measurement accuracy of the bright spot position. Or, select a plurality of light emitting parts to light up,
The pupil measurement is performed under the condition that the light amount distribution obtained by the light receiving element is not affected by the eye refractive power of the subject's eye.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

Reference numeral 1 is a projection system for projecting a measurement light source image onto the fundus 7 of the eye 3 to be inspected, and 2 is a light receiving system for receiving the light beam 10 reflected by the fundus 7, the projection system 1 and the light receiving system. The system 2 is arranged to face the eye 3 to be inspected.

The projection system 1 is positioned at an intersection of four slit-shaped light emitting portions 4a, 4b, 4c, 4d and two meridians located on two orthogonal meridians in a plane orthogonal to the optical axis of the projection system. A measuring light source unit 4 having a point light source 4e, and a half mirror 5 for reflecting the light beam 11 from the slit light emitting units 4a, 4b, 4c, 4d and the point light source 4e toward the eye 3 to be examined. The projection system 1 comprises a slit-shaped light-emitting portion 4a, 4b, 4c, 4d and a luminous flux 11 emitted from a point-shaped light source 4e through a pupil 6 and a fundus 7 on the fundus 7.
The images a, 4b, 4c and 4d and the point light source 4e are projected so as to form images.

Next, the measurement light source unit 4 will be described with reference to FIGS.

The measuring light source unit 4 includes a light shielding member 12 which will be described later.
The slit portions 20a, 20b, 20c, 20d orthogonal to the edge portions 12a, 12b, 12c, 12d, and the target plate 16 in which the transmission holes 20e are formed at the intersections of the center lines of the slit holes, and the slit holes 20a, 20b, 20
Corresponding to c and 20d, slit-shaped light emitting portions 4a and 4 are formed by linearly arranging light emitting bodies such as LEDs that emit infrared light.
b, 4c, 4d and a point emission source 4e corresponding to the transmission hole 20e.

Further, the target plate 16 has a meridian different from the meridian in which the slit holes 20a, 20b, 20c and 20d are arranged (in this embodiment, another meridian forming an angle of 45 ° with the meridian of the slit holes). LED that emits visible light on the meridian)
A required number of equal light emitting bodies 17 are provided at a required pitch.
The pattern formed by the light-emitting body 17 is a fixation target, and the light-emitting body 17 is designed to be capable of blinking sequentially from the periphery toward the center.

The light receiving system 2 comprises an objective lens 8 and a light receiving element 9, and a light beam 10 from the fundus 7 is reflected by the half mirror 5.
Is guided through the light receiving element 9. The light receiving element 9 is
It is an area CCD, an image pickup tube or an assembly of two or more light receiving elements, and the light receiving surface 9a of the light receiving element 9 is arranged at a conjugate position with the pupil 6 of the eye 3 to be inspected with respect to the objective lens 8.

In the optical path of the light receiving system 2, when the eye refractive power of the eye 3 to be inspected has a reference diopter value, the slit-shaped light emitting portions 4a, 4 are formed at the positions where the light emitting portion images are formed.
A light blocking member 12 having edge portions 12a, 12b, 12c, 12d for blocking one side of each of the light beams from b, 4c, 4d is arranged in a plane perpendicular to the optical axis.

A square hole 18 is formed in the light shielding member 12, and the four sides of the hole 18 are the slit-shaped light emitting portions 4a, 4a.
edge portions 12a, 12 orthogonal to the images b, 4c, 4d
b, 12c, 12d.

An arithmetic unit 13 is connected to the light receiving element 9, and the arithmetic unit 13 stores the data of the light receiving state of the light receiving element 9 in each radial line and further calculates the result, and the result is displayed on the display unit 1.
It is designed to output to 4. Further, the slit-shaped light emitting units 4a, 4b, 4c, 4d, the point light source 4e, and the driver 15 for driving the light emitter 17 are connected to the arithmetic unit 13, and the arithmetic unit 13 connects the slit-shaped light emitting unit 4a, Four
The lighting states of b, 4c, 4d and the point light source 4e are controlled via the driver 15.

The operation will be described below.

First, when the measurement is started, the device and the subject, especially the eye to be inspected, are aligned. The target plate 16 is a fixation target, and the illuminant 17 is the center. By sequentially blinking, the subject naturally collimates the center by this movement, and the line of sight of the subject's eye can be fixed to the optical axis of the measuring device. Further, it is still more effective if the sound is emitted in accordance with the blinking of the light emitting body 17.

When the alignment is completed, first the eye refractive power is measured.

A signal from the computing unit 13 is used to output the slit-shaped light emitting portions 4a, 4b, 4 via the driver 15.
One of c and 4d is selected and turned on. The light amount distribution and the eye refractive power are obtained for the meridian to which the selected slit-shaped light emitting unit belongs.

FIG. 1 shows a state in which the eye 3 to be inspected has a reference diopter value. In this state, the reflected light beam 10 has an edge portion corresponding to the selected light emitting portion of the light shielding member 12. Focus on the top. In this state, the light blocking member 1
When 2 blocks a part of the reflected light beam 10, the light amount distribution of the light beam projected on the light receiving surface 9a becomes uniform.

Next, in the eye to be inspected having a diopter value larger or smaller than the reference diopter value, the condensing position of the reflected light beam 10 is closer to the eye 3 side than the edge portion of the light shielding member 12 depending on the size of the diopter value. Or, it is biased toward the objective lens 8 side. Due to this bias, the light blocking state of the reflected light beam 10 by the light blocking member 12 changes, and the light amount distribution of the light beam projected on the light receiving surface 9a becomes uneven and has an inclination. Furthermore, this tilt corresponds to the eye power.

The calculator 13 takes in a light-receiving signal for one screen of the light-receiving element 9 and calculates the light amount distribution state and the eye refractive power.

This measurement of the eye refractive power is also performed for other light emitting parts, and the eye refractive power is obtained for a plurality of meridians. Furthermore, the astigmatic axis angle and the degree of astigmatism can also be calculated from the eye refractive power of a plurality of meridians. These calculation results are displayed on the display 14 as measurement results.

Further, if the eye refractive powers of the slit-shaped light emitting portion 4a and the slit-shaped light emitting portion 4b are measured on the same meridian and averaged, the measurement accuracy is improved.

At the time of measuring the line-of-sight direction and the pupil diameter, only the point light source 4e is turned on by the calculator 13 via the driver 15.

The reflected light beam 10 from the fundus 7 of the point light source 4e is the edge portions 12a, 12b, 12c, 1 of the edges.
2d is hardly affected, or even if it is, the edge portions 12a, 12b, 12c, 12d are evenly affected, so that the light quantity distribution of the light beam projected on the light receiving surface 9a is equal to the eye refractive power. It becomes uniform regardless of how it is done. Therefore, if the pupil diameter is obtained from the light amount distribution obtained by turning on the point light source 4e, the pupil diameter can be measured with high accuracy, and as a result, the position of the pupil image can be accurately obtained.

Next, depending on the light quantity distribution or the light receiving surface 9a
The position of the bright spot due to corneal reflection is measured from the pupil image itself, but the corneal reflection image is also very sharp because the point light source 4e is close to the point light source (since the viewing angle of the light source from the subject's eye 3 is narrow). It becomes close to a point, and the detection accuracy of the bright spot position is accurate.

Thus, the position of the pupil image and the position of the bright spot can be detected accurately, and the measurement of the line-of-sight direction can be performed accurately, and the abnormal eye position can be also accurately measured.

If the position of the bright spot can be measured sufficiently at the time of measuring the eye refractive power, the point light source 4e can be omitted. In this case, the slit light emitting section 4a,
4b, 4c, 4d are turned on and the edge portions 12a, 12
The pupil image position may be measured while canceling out the effects of b, 12c, and 12d.

Further, although the measuring light source and the edge portion are arranged in the 4-meridian direction, they may be in the 6-meridian direction or the 1-meridian direction.

Further, in order to improve the accuracy of the bright spot position measurement in the above-mentioned embodiment, the point light source 4e was switched, but when the light emitting portion is a set of point light sources such as LEDs, the LEDs constituting the light emitting portion are formed. It is also possible to turn on only a part of the light source and change the light emitting area of the light emitting unit itself to bring it closer to the point source. In this case, the point light source 4e can be omitted.

[0034]

As described above, according to the present invention, the eye refractive power can be measured, the eye direction and the pupil diameter can be accurately measured, and accurate eye position measurement can be performed together. Be effective.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a view on arrow AA of FIG.

FIG. 3 is a view taken along the line BB of FIG.

FIG. 4 is an explanatory diagram of pupil diameter measurement.

FIG. 5 is an explanatory diagram of a corneal reflection image measurement.

[Explanation of symbols]

1 Projection system 2 Light receiving system 3 eye 4 Measuring light source 4a Slit-shaped light emitting unit 4b Slit-shaped light emitting unit 4c Slit-shaped light emitting part 4d slit-shaped light emitting unit 4e point light source 7 fundus 9 Light receiving element 12 Light-shielding member 13 arithmetic unit 14 Display 15 driver

Claims (3)

(57) [Claims] 1. A measurement light source, a projection system for projecting a measurement light source image on the fundus of the eye to be inspected, and a light flux reflected from the fundus of the eye to be inspected on a light receiving element arranged substantially conjugate with the pupil of the eye to be inspected. A light-receiving system and an edge-shaped light-shielding member that blocks a part of the reflected light beam disposed in the light-receiving system, and the eye refractive power of the eye to be inspected from the eye image of the eye to be inspected formed on the light receiving element. In an eye-refractive-power measuring device for measuring the pupil diameter or the corneal reflex bright spot image position of the optometry, the light-emitting area of the measurement light source is variable, and the light-emitting area is reduced in the measurement except the eye-refractive-power measurement. An eye refractive power measuring device characterized by the above. 2. A pre-Symbol measurement light source has a plurality of light emitting portions, when the eye refractive power measurement, the pupil diameter measuring scheduled to claim 1 configured such that lights by selecting the appropriate position among the plurality of light emitting portions Eye refractive power measuring device. 3. At least one light emitting portion is partially shielded by the light shielding member from a light beam reflected from the fundus of the eye to be examined, and at least another light emitting portion is shielded from light shielding member from the light beam reflected from the fundus of the eye to be examined. The eye refractive power measuring device according to claim 2, which is not shielded from light or is not affected by light shielding.