JPH05111461A - Opthalmorefractometer - Google Patents

Abstract

PURPOSE:To provide the ophthalmorefractometer which is relatively simple in operation, is small in size and does not require image processing. CONSTITUTION:An IR luminous flux I is reflected by a beam splitting member 3 when an IR light source 5 emits light. This luminous flux transmits a moving lens 2 which is movable in an optical path direction and is reflected by a dichroic mirror 1. The reflected light is made incident at the luminous flux larger than the pupil diameter on an eye E to be examined. The eyeground reflected light L which is transmitted through the pupil Ep and is reflected by the eyeground Er is reflected by the dichroic mirror 1 transmits the moving lens 2 and the beam splitting member 3 and images on a photodetecting element 4. The refractive power of the eye E to be examined is decided from the relation between the brightness distribution on the photodetecting element 4 and the position of the moving lens 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eye refractometer used in ophthalmology clinics and eyeglass stores.

[0002]

2. Description of the Related Art A so-called Maxwell optics type eye refractometer which has been conventionally used has an aperture arranged at a pupil conjugate position of an objective lens to accurately project a light beam smaller than a pupil onto the center of the pupil. , The eye refractive power is measured from the fundus reflected light. Since this type of eye refractometer needs to accurately project the light flux into the pupil, it requires a fixed base for fixing the subject's face and a sliding function for minutely moving the light flux vertically and horizontally. It is generally a stationary type. Also,
There is also known a photorefraction device capable of performing eye refraction measurement at a distance of about 50 cm to 1.5 m from a subject.

[0003]

However, since it is necessary to fix the face to the face cradle in the Maxwell optics type eye refractometer, it is difficult to use it for infants. Further, the photorefraction device has problems that the device is large and image processing is required, and the measurable refractive power range is narrow. Furthermore, since both devices are large in size, it is difficult to apply them to a hand-held eye refractometer or a device capable of self-measurement.

It is an object of the present invention to provide an eye refractometer which is relatively easy to operate, is small in size, does not require image processing, and is capable of handheld measurement and self-eye measurement as needed.

[0005]

In order to achieve the above object, an eye refractometer according to the present invention illuminates an eye to be inspected with a light beam emitted from a light source and passing through a light splitting member and a moving lens and having a diameter larger than a pupil diameter. An illumination optical system, and a light receiving system including a photodetector arranged at a position conjugate with the light source with respect to the light splitting member, and the eye to be inspected based on the information from the moving lens and the photodetector. It is characterized in that the eye's refractive power is calculated.

[0006]

In the eye refractometer having the above-described structure, the light receiving state of the fundus reflected light from the eye to be examined changes in accordance with the state of the moving lens, and the eye refraction value of the eye to be examined is changed from the state of the light receiving state and the state of the moving lens. To calculate.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. FIG. 1 is a block diagram of the first embodiment. A dichroic mirror 1 that reflects infrared light and transmits visible light is arranged in the line-of-sight direction of the eye E to be inspected, and a movable lens 2, a light splitting member 3, and a light-receiving element that are movable back and forth in the reflection direction of the dichroic mirror 1. 4 is arranged, and further, an infrared light source 5 for generating infrared light is arranged in the reflection direction of the light splitting member 3.
2 and 3 are front views of the light receiving element 4 and the infrared light source 5.
The light-receiving element 4 has a circular light-receiving surface and is divided into seven parts. The center of the light-receiving element 4 is a circular element sensor 4a, and the peripheral portion 4a around the light-receiving element 4 is divided into six equal element sensors 4b to 4g. The infrared light source 5 is a circular light emitting element and radiates infrared light uniformly from the surface.

At the time of measurement, the examiner aligns the eye E to be examined from the rear of the dichroic mirror 1, presses a measurement button (not shown), the infrared light source 5 emits light, and the incident light flux I reflected by the light splitting member 3 is measured. Passes through the moving lens 2 and is reflected by the dichroic mirror 1 to reach the eye E to be inspected. Luminous flux I
Is sufficiently large with respect to the pupil Ep, so that the light flux transmitted through the pupil Ep reaches the fundus Er regardless of a slight misalignment in alignment. The fundus reflected light L returns along the same path, and the light splitting member 3
And is incident on the light receiving element 4.

The relationship between the position of the moving lens 2 and the ratio of the amount of light received by the light receiving element 4 is as shown in FIG. The ratio of the output of the element sensor 4a at the center of the light receiving element 4 and the sum of the outputs of the element sensors 4c and 4f on both sides on the radial line m has a peak at a predetermined position of the moving lens 2. 60 ° to the radial line m,
In the radial lines 1 and n rotated by 120 °, the peaks of the amount of received light relative to the position of the moving lens 2 are relatively deviated.
Since this deviation depends on the eye refractive power of the eye E to be inspected, the moving lens 2 is moved to find the position of the moving lens 2 having the maximum light amount ratio with respect to the three radial lines m, l, and n. The refractive power of the optometry E can be determined.

Since the incident light flux I is sufficiently larger than the pupil Ep, the incident light flux I is incident on the fundus Er even if the light flux deviates to some extent, and the allowable alignment range is large. Further, since the reference position of the moving lens 2 is determined from the light quantity ratio of the light receiving element 4, the influence on the luminance of the light source 5 and the measurement error due to scattered light from the outside is small.

When this embodiment is used in a hand-held refractometer, the examiner measures the refractive power while observing the eye E to be examined through the dichroic mirror 1. Further, when used for self-measurement, the visual target viewed by the subject may be provided in the direction of the dichroic mirror 1.

FIG. 5 is a front view of a light receiving element 4'of another type,
FIG. 6 is a front view of the infrared light source 5 '. In this embodiment, the infrared light source 5'is rectangular, and the light receiving element 4'corresponding to this is square.
Is provided with an element sensor 4h in the center and rectangular element sensors 4i to 4l in the cross direction. In this case, 2
The eye refractive power in the direction can be obtained.

FIG. 7 is a front view of a horopter to which the first embodiment is applied. The objective refraction measuring unit 7 is attached to the horopter section 6.
Has been added. A lens turret is housed in the horopter unit 6, and lens units 9a and 9b having viewing windows 8a and 8b in the inner lower portion and the lens units 9a and 9b can be adjusted from above according to the pupil distance of the subject S. It is composed of a holding unit 10 for holding. The objective refraction measuring unit 7 has the same configuration as that of the first embodiment, is vertically long and is provided with the dichroic mirror 1 at the bottom, is slidably supported by the holding portion 10, and its position can be changed according to the left and right eyes. It is like this.

For example, at the time of right eye ocular refraction measurement, the observation window 8a and the dichroic mirror 1 of the objective refraction measuring unit 7 are aligned with each other and the measurement is performed by the same operation as in the first embodiment. When the viewing window 8a has a lens, reflected light from the lens causes noise, but there is no problem because the refracting power is determined from the relative ratio of the light amounts in the light receiving element 4. In addition, the objective refraction measurement unit 7 includes the left and right lens parts 9a, 9a.
It may be independently provided in b. When the measurement is not performed, it is desirable that the objective refraction measuring unit 7 be slid and retracted laterally.

FIG. 8 is a block diagram of the second embodiment. On the optical path from the light source 11 to the eye E to be inspected, a black spot plate 33 movable in the optical axis direction and having a light-shielding black spot 12a in the central portion, a light splitting member 13, and a moving lens 14 are sequentially arranged.
The image of the light source 11 can be projected onto the fundus Er of the eye. A finder optical system including a light splitting prism 15 having a reflecting surface 15a at its center, a lens 16, and an eyepiece 17 is provided in the transmission direction of the fundus reflected light through the light splitting member 13. Further, in the reflection direction of the reflection surface 15a, a light receiving element 18 having a positional relationship with the light source 11 with respect to the movable lens 14 is arranged.

FIG. 9 is a front view of the light source 11, and FIG. 10 is a front view of the light receiving element 18. The light emitting surface of the light source 11 is a square, and the light receiving surface of the light receiving element 18 is vertically divided into three element sensors 18a. , 18b, 18c. The light receiving element 18 obtains outputs and output ratios of the element sensor 18a at the center and the element sensors 18b and 18c on both sides when the refracting powers are different from each other in the horizontal and vertical directions. calculate.

The eye optometry e looks into the eyepiece lens 17, confirms that the eye E to be inspected is substantially at the center, and a measurement button (not shown) is pressed to perform the measurement. The light flux emitted from the light source 11 passes through the black spot plate 33, the light splitting member 13, and the moving lens 14 to project a light source image on the fundus Er of the eye E to be examined. The fundus reflected light returns through the same optical path and enters the light receiving element 18 via the light splitting member 13 and the light splitting prism 15. Then, the moving lens 14
Is manually or automatically moved in the optical path direction to
The refractive power of the eye E to be inspected can be obtained from the position of the moving lens 14 when the signal of 1 is in focus. The light-shielding black dots 12a of the black dot plate 33 prevent the reflected light of the moving lens 14 from entering the light receiving element 18 and becoming noise.

In this embodiment, the light receiving element 1 in the vertical direction is also used.
8 is used, it is possible to obtain the eye refractive power including astigmatism by using the light receiving elements 4 and 4'shown in FIGS.

FIG. 11 is a block diagram of the third embodiment. In this embodiment, the light splitting member 13 in the second embodiment is replaced with a polarizing element, and the light receiving element 18 is replaced with a CCD element 21 so that the observation optical system and the eye refraction measuring system can be performed by the same member. ing. That is, the polarized light splitting member 20 and the movable lens 23 that can move in the optical axis direction are provided between the light source 22 and the subject's eye E, and the CCD element 21 is placed in the transmission direction of the polarized light splitting member 20. The television camera 24 which it has is arranged. The output of the TV camera 24 is connected to a TV monitor 26 equipped with an eyepiece 25.

The light beam emitted from the light source 22 is reflected by the polarized light splitting member 20 which is a polarizing element utilizing Brewster's angle, passes through the movable lens 23 movable in the optical axis direction, and is incident on the distant eye E. It is like this. The reflected light of the eye E to be inspected passes through the movable lens 23, and only the light beam whose polarization has been lost due to fundus reflection passes through the polarized light splitting member 20,
The light can be incident on the CCD element 21 of the television camera 24 arranged at a position conjugate with the light source 22 and the moving lens 23. The eye E can confirm the eye E through the TV monitor 26 and the eyepiece 25, which are output from the TV camera 24.

FIG. 12 is a front view of the television monitor 26. When the examiner puts the eye E to be examined in the approximate center of the visual field of the television monitor 26 and presses the measurement button, the light source 22 emits light and the reflected light from the eye E is reflected. Is projected onto the CCD element 21. When the movable lens 23 moves in the optical axis direction and becomes in focus, the focus lamp 27 lights on the TV monitor 26, and at the same time, the refractive power D of the eyeglass lens suitable for the eye E calculated by the computer (not shown) is displayed. To be done. In this embodiment, since the polarization element is used as the polarized light splitting member 20, the reflected light of the moving lens 23 does not enter the CCD element 21 and noise is reduced.

FIG. 13 is a block diagram of the fourth embodiment, in which an observation optical system for the eye E is separately provided. On the optical path 01 by the light source 30 of the measurement optical system, a light-shielding black dot 31 is formed at the center.
a black dot plate 31 having a, a light splitting member 32, a moving lens 3
3 are sequentially arranged and reach the eye E to be inspected. Further, a light receiving element 34 is provided behind the light splitting member 32 at a position conjugate with the light source 30. On the optical path 02 of the observation optical system, the objective lens 35, the split prism 36, and the eyepiece 37 on the focal plane of the objective lens 35 are arranged in this order from the eye E side so that the examiner can observe from the eyepiece 37. There is. The optical system of the observation system and the optical system of the measurement system are arranged so as to be focused and matched at a predetermined distance, for example, 1 m.

At the time of measurement, the subject is fixed, and the optometry e is adjusted so that the split prism 36 can be seen correctly. When a measurement button (not shown) is pressed, the light source 30 emits light and the movable lens 33 moves back and forth to perform measurement. Since the observation optical system is provided independently of the measurement optical system, the focus is not defocused even during measurement, and the eye E to be inspected can be continuously observed.

FIG. 14 shows a fifth embodiment. In this embodiment, the main optical paths of the observation optical system and the measurement optical system, which have been separated in the above-mentioned third embodiment, are coaxial. On the optical path O3 from the light source 40 to the eye E, a light splitting member 41, a moving lens 42 having a light-shielding black spot 42a on the optical axis, a reflecting surface 43a at the center, and a surface perpendicular to the optical axis. A light splitting prism 43 slightly inclined with respect to the light splitting prism 43 is sequentially provided, and a light receiving element 44 is provided behind the light splitting member 41 at a position conjugate with the light source 40. On the optical path 04 on the reflection side of the reflection surface 43a, the mirror 45 and the lenses 46 and 47 are sequentially arranged to reach the optometry e.

The measurement is carried out using a process similar to the embodiment described above. Reflection by the moving lens 42 is a black dot 4
It is removed by 2a and does not enter the light splitting prism 43. Further, the light splitting prism 43 may be replaced by a partial mirror.

FIG. 15 is a block diagram of the sixth embodiment. In the optical path from the light source 50 to the eye E to be inspected, a light splitting member 51 including a half mirror or a polarizing element, and movement for driving in the optical axis direction. A lens 52 is arranged, behind the light splitting member 51, at a position conjugate with the light source 50 with respect to the light splitting member 51,
A television camera 54 having a CCD element 53 is arranged. The output of the television camera 54 is connected to the television monitor 55 and the signal processor 56, and the output of the signal processor 56 is connected to the driving means for moving the moving lens 52. Further, the optometry e can observe the television monitor 55 through the eyepiece 57.

When the light source 50 emits light, the light beam reflected by the light splitting member 51 passes through the moving lens 52 and enters the eye E to be examined. The reflected light from the eye E to be examined passes through the moving lens 52 and the light splitting member 51 and is received by the CCD element 53. The movable lens 52 is moved in the optical axis direction by a manual or automatic focusing device, and the refraction value of the eye E to be inspected by the signal processor 56 from the relative position of the light splitting member 51 when the anterior segment is focused and when the fundus is focused. Is required. Further, if the distance to the eye E is predetermined, it is not necessary to measure the position of the light splitting member 51 when focusing on the anterior segment.

FIG. 16 is a front view of the light source 50, and FIG.
Is the external eye image E ′ and the light source image 50 projected on the CCD element 53.
It is a front view of a, 50b, 50c. To focus
When the moving lens 52 moves and the fundus Er of the eye E and the light source 50 are conjugated, an image 50a of the light source 50 is formed on the CCD element 53. The size and position of the image on the CCD element 53 at this time are always constant because they are irrelevant to the distance between the eye E and the apparatus and the state of incidence of the light beam on the eye E. The ratios of the signal magnitudes of the images 50b and 50c on both sides of the image 50a and the signal magnitude of the image 50a are calculated, and when the signal ratio is maximum, the image is in focus. The focus can be adjusted automatically by processing the signal in the area.

FIG. 18 is a block diagram of the seventh embodiment. In this embodiment, the light splitting member is arranged on the eye E side in order to reduce noise due to lens reflection. Light source 6
A moving lens 61 and a light dividing member 62 are provided on the optical path from 0 to the eye E, and a moving lens 63 and a CC having the same function as the moving lens 61 are provided behind the light dividing member 62.
A television camera 65 having a D element 64 is provided, and the light source 60 and the moving lens 61 are arranged so as to be conjugate with the light dividing member 62 with respect to the moving lens 63 and the CCD element 64.

At the time of measuring the eye refractive power, the luminous flux emitted from the light source 60 passes through the moving lens 61 and is reflected by the light dividing member 62 toward the eye E to be inspected. The reflected light from the eye E to be examined passes through the light splitting member 62 and is moved to the C by the moving lens 63.
An image is formed on the CD element 64. The moving lens 61 and the moving lens 63 operate in conjunction with each other, and the moving lens 6 in the in-focus state of the anterior segment and the fundus is controlled by an automatic focus detection mechanism (not shown).
1 or the position of the moving lens 63 is measured to obtain the eye refractive power.

Further, since the moving lens 61 is located closer to the light source 60 than the light splitting member 62, strong reflected light from the moving lens 61 does not directly enter the CCD element 64, and noise is reduced. Furthermore, after focusing on the fundus, the moving lens 6
1 and the moving lens 63 are quickly returned to the anterior segment focusing position,
It is convenient to be able to confirm whether or not the eye E has moved during the measurement.

The luminous flux used for the measurement may be visible light or infrared light, and the eye refractive power can be measured in the same manner.

[0033]

As described above, the eye refractometer according to the present invention guides a light beam having a diameter sufficiently larger than the pupil diameter to the eye to be inspected and measures the eye refracting power by utilizing the reflected light. Does not require rigor.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a front view of a light source.

FIG. 3 is a front view of a light receiving element.

FIG. 4 is a diagram showing the relationship between the position of a moving lens and the amount of light received by a light receiving element.

FIG. 5 is a plan view of a light source.

FIG. 6 is a front view of a light receiving element.

FIG. 7 is a front view of a horopter to which the first embodiment is applied.

FIG. 8 is a configuration diagram of a second embodiment.

FIG. 9 is a front view of a light source.

FIG. 10 is a front view of a light receiving element.

FIG. 11 is a configuration diagram of a third embodiment.

FIG. 12 is a front view of a television monitor.

FIG. 13 is a configuration diagram of a fourth embodiment.

FIG. 14 is a configuration diagram of a fifth embodiment.

FIG. 15 is a configuration diagram of a sixth embodiment.

FIG. 16 is a front view of a light source.

FIG. 17 is an explanatory diagram of an image on a CCD element.

FIG. 18 is a configuration diagram of a seventh embodiment.

[Explanation of symbols]

1 dichroic mirror 2, 14, 23, 33, 42, 52, 61, 63 moving lens 3, 13, 41, 51, 62 light splitting member 4, 4 ', 18, 34, 44 light receiving element 5, 5', 11 , 22, 30, 40, 50, 60 Light source 20 Polarized light splitting member 24, 54, 65 Television camera 26, 55 Television monitor

Claims (5)

[Claims] 1. An illumination optical system for illuminating an eye to be inspected by a light flux emitted from a light source and passing through a light splitting member and a moving lens, and a light arranged at a position conjugate with the light source with respect to the light splitting member. And a light receiving system equipped with a detector,
An eye refractometer, wherein the eye refractive power of the eye to be inspected is obtained based on the information from the moving lens and the photodetector. 2. The eye refractometer according to claim 1, further comprising an observation optical system for observing an eye to be inspected through the light splitting member. 3. The eye refractometer according to claim 1, further comprising a light blocking member that prevents the reflected light of the moving lens from entering the light receiving system. 4. The eye refractometer according to claim 1, wherein the photodetector is a video camera. 5. The eye according to claim 4, wherein signals of the light source image on the image receiving surface of the video camera or the photoelectric element and a peripheral portion of the image are used for focusing means of the video camera. Refractometer.