JPH11285472A - Eye examination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To implement an accurate measurement of diopter while downsizing the structure. SOLUTION: Wavelength light from a light source 23 for diopter measurement that is comprised of a point light source passes a dichroic mirror 10, and reflects from a dichroic mirror 17. A 6-hole diaphragm 24 has six openings provided at an equal distance at an equal angle around an optical axis and is arranged conjugately to the pupil. A prism plate 26 is comprised of six wedge prisms. A light flux projected on the eyeground Er of an examined eye E from the diopter measurement light source 23 is reflected by the eyeground Er, and reflected further by a perforated mirror 20, and passes through the openings of the six-hole diaphragm 24 and are projected on a two-dimensional array sensor 19 by the lens 25, and reflected light is taken out from radial six positions of the surrounding of the pupil. The radial refractive power is measured from the clearance between two light spots on each radial line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eye measuring apparatus used for measuring an eye refraction value.

[0002]

2. Description of the Related Art Conventionally, there has been a demand for an eye measuring apparatus having a reduced configuration, and in particular, an apparatus capable of performing highly accurate eye refraction measurement while achieving downsizing is desired.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an eye measuring apparatus capable of performing a highly accurate eye refraction measurement without reducing the measuring accuracy while reducing the size of the structure.

[0004]

An eye measuring apparatus according to the present invention for achieving the above object comprises a projection system for projecting a point light beam from the center of the pupil to the fundus of the eye to be examined, and a fundus reflected light from the periphery of the pupil. A light receiving system for receiving light with a two-dimensional optical position sensor via a light deflecting member provided substantially conjugate with the pupil, wherein the light deflecting member deflects a light beam from each part around the pupil in a direction away from the optical axis. Features.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. For example, FIG. 1 shows a first example for understanding the present invention, in which an objective lens 1 is arranged so as to face an eye E to be inspected, and an aperture 2, a light splitting member 3, 4. A one-dimensional sensor array 6a composed of a cylindrical lens 5a, a CCD and the like is arranged. Further, a cylindrical lens 5b and a one-dimensional sensor array 6b are arranged in the reflection direction of the light dividing member 3, and a cylindrical lens 5c and a one-dimensional sensor array 6c are arranged in the reflection direction of the light dividing member 4. As shown in FIG. 2 around the optical axis O, six measurement light sources 7a to 7f are arranged at equal angles and equal distances. Point light sources such as light-emitting diodes are used for these measurement light sources 7a to 7f, and two light sources are arranged in at least three radial directions, and the measurement light sources 7a and 7d, 7b and 7e, and 7c and 7f They are arranged in the AD, BE, and CF directions.
However, when the cornea Ec of the eye E and the alignment of the apparatus match, one light source 7 may be provided for each radial line.

The generatrix direction of the cylindrical lens 5a and the array direction of the one-dimensional array sensor 6a are in the direction of the radial line AD.
The cylindrical lens 5a functions to focus the light beam on the one-dimensional array sensor 6a. Similarly, the generatrix direction of the other cylindrical lens 5b and the arrangement direction of the one-dimensional array sensor 6b,
And the direction of the generatrix of the cylindrical lens 5c and the one-dimensional array sensor 6
The arrangement direction of c is the direction of each radial line BE and CE. The diaphragm 2 and each one-dimensional array sensor 7 are conjugated by each cylindrical lens 6 in a direction perpendicular to the generatrix of each cylindrical lens 6.

In this example, the measurement light sources 7a and 7d form virtual images 7A 'and 7D' on the cornea Ec of the eye E, respectively, and these images 7A 'and 7D' are The light is projected onto the one-dimensional array sensor 6a through the division members 3, 4 and the cylindrical lens 5a. Similarly, the images of the measurement light sources 7b and 7e are reflected by the light splitting member 3 and projected on the one-dimensional array sensor 6b through the cylindrical lens 5b. Further, the images of the measurement light sources 7c and 7f are also reflected by the light dividing member 4 and are projected on the one-dimensional array sensor 6c through the cylindrical lens 5c. In this case, it is desirable to dispose the stop 2 in the vicinity of the rear focal position of the objective lens 1 in order to reduce the error due to the working distance.

FIG. 3 is an explanatory view of the cylindrical lens 5a and the one-dimensional array sensor 6a. Since the virtual images 7A 'and 7D' become images 7A "and 7D" on the one-dimensional array sensor 6a, their positions can be obtained. I just need. The corneal shape such as the corneal radius of curvature and corneal astigmatism can be measured from the positions on the three-diameter line thus determined.

Since the cornea Ec generally has astigmatism, it is assumed to be a spheroid. First, when there is no center of curvature of the cornea Ec on the optical axis O, the two images on the one-dimensional array sensor 7 are asymmetric with respect to the center. That is, the two images 7A ", 7A shown in FIG.
The center coordinate of D "indicates the eccentricity in the direction of the radial line AD, and indicates the eccentricity in two directions. Therefore, the two-dimensional eccentricity can be measured by the center coordinates in the two directions.

Further, even if there is eccentricity, the distance between the images remains unchanged, and this distance is inversely proportional to the sum of the reflective spherical power of the cornea Ec and its radial component of the reflective cylindrical power. From this relationship, three relational expressions can be obtained for the three diameter lines. Since the unknowns are the spherical surface, the cylindrical refractive power, and the angle, the spherical refractive power and the like are calculated from these simultaneous equations. Is possible.

FIG. 4 shows a second example for understanding the present invention, wherein the same numbers as in FIG. 1 represent the same members.
In this embodiment, a cylindrical lens plate 8 is used instead of using the light splitting members 3 and 4 of FIG. As shown in FIG. 5, the cylindrical lens plate 8 has three-diameter wires AD, BE, and CF.
Cylindrical lenses 8a to 8a each having a generatrix in the directions of
f and has a wedge shape as shown in FIG. 6 and has a function of refracting a light beam in the optical axis O direction. As the optical position sensor, a two-dimensional area array sensor 9 such as a photographing CCD as shown in FIG. 7 is used.

The image 7A ", on the line of the radial lines AD, BE, CF,
7D "etc. are projected, so that these images 7A", 7D "
The corneal shape can be measured from the interval as described above. The cylindrical lens plate 8 is arranged at a position where light beams from six light source images pass through the stop 2 and are separated, and similarly conjugate the stop 2 and the area array sensor 9 in a direction perpendicular to the generatrix. Further, the deflection action by the wedge-shaped cylindrical lenses 8a to 8f helps the light flux of the enlarged image to enter the area sensor array 9 to improve the accuracy.

FIG. 8 shows an embodiment of the present invention. This embodiment has both functions of measuring the refraction of the eye and measuring the shape of the cornea, and shares a light receiving unit. First, in the corneal shape measurement system, measurement light sources 7a to 7d, which are point light sources, are arranged in the same manner as in FIG. 1, but a dichroic mirror 10 is obliquely provided behind the objective lens 1 and its reflection is performed. The lens 11, the diaphragm 12, the cylindrical lens plate 13, and the lens 1
4 are sequentially arranged. Behind the lens 14, a lens 16, a dichroic mirror 17, a cylindrical lens plate 18, and a two-dimensional array sensor 19 are sequentially arranged via a total reflection mirror 15 for optical path conversion.

Here, the stop 12 is located near the rear focal point of the optical system including the objective lens 1 and the lens 11, and the cylindrical lens plate 13 is the same as the cylindrical lens plate 8 shown in FIGS. It has the same configuration, and the wedge-shaped deflection directions are the AD, BE, and CF directions. Lens 1
Reference numeral 4 denotes a field lens, on which a corneal image is projected, and this surface is scanned by a lens 16 with a two-dimensional array sensor 19.
It is designed to project upward. The dichroic mirror 17 has a characteristic of transmitting wavelength light from the measurement light sources 7a to 7d. The six measurement light sources 7a to 7a
f lights up one by one. As shown in FIG. 9, the cylindrical lens plate 18 is composed of three cylindrical lenses 18a, 18b and 18c having a generatrix in the measurement radial direction, is located near the two-dimensional array sensor 19, and collects light in the direction perpendicular to the generatrix. It acts to light.

An image projected on the two-dimensional array sensor 19 is, for example, as shown in FIG. 10, and a light beam is projected on a specific diameter line indicated by the same diameter line AD, BE, CF as the measurement diameter line. The corneal shape can be measured from the distance between two light spots on these diameter lines.

Next, regarding the eye refraction measuring system, a perforated mirror 20 behind the dichroic mirror 10 on the optical axis O is used.
Then, a stop 21, a lens 22, and a refraction measurement light source 23 are sequentially arranged, and a six-hole stop 24, a lens 25, a prism plate 26, and a dichroic mirror 17 are arranged on the optical axis on the reflection side of the perforated mirror 20. ing.

The wavelength light from the refraction measuring light source 23 passes through the dichroic mirror 10 and reflects off the dichroic mirror 17. Refraction measurement light source 23
, A point light source such as a light emitting diode is used, which is desirably arranged conjugate with the fundus Er of the eye E to be examined. The refraction measurement light source 23 is imaged by the lens 22 near the rear focal point of the objective lens 1. The diaphragm 21 has an opening at the center and is substantially conjugate with the pupil of the eye E to be examined. Also, 6
As shown in FIG. 11, the hole stop 24 has six openings 24a to 24f provided at equal distances and at equal angles around the optical axis, and is similarly conjugated to the pupil. Prism plate 26
Are six wedge prisms 26a to 26f as shown in FIG.
The two-dimensional array sensor 19 is conjugate with the refraction measuring light source 23 when the refractive power of the cylindrical lenses 18a, 18b, 18c is not considered.

The light beam from the refraction measurement light source 23 passes through the lens 22, the aperture 21, the hole of the perforated mirror 20, the dichroic mirror 10, and the objective lens 1, and passes through the fundus Er of day E.
Are projected to a point. The reflected light beam from the fundus Er passes through the objective lens 1 and is reflected by the perforated mirror 20.
The light is projected on the two-dimensional array sensor 19 through the lens 25 and the prism plate 26 through the opening 4. In this case, since the 6-hole aperture 24 is conjugate to the pupil, 6 apertures 24 in the three radial directions around the pupil are provided.
The reflected light can be extracted from the location.

If the prism plate 26 is not provided, the six luminous fluxes from the fundus Er of the eye E to be examined in the normal eye will be concentrated at one point in the center, but the prism plate 26 independently measures the positions of these six luminous fluxes. It separates on the two-dimensional array sensor 19 as much as possible and deflects in each direction of the cylindrical lenses 18a, 18b, 18c. For example, the light beams emitted from the openings 24a and 24d of the 6-hole aperture 2a reach the radial line AD on the two-dimensional array sensor 19 through the cylindrical lens 18a. Light beams from the apertures 24b and 24e of the 6-hole aperture 24 pass through the cylindrical lens 18b and reach the radius line BE.
Similarly, since the light fluxes from the openings 24c and 24f reach on the radial line CF, the refractive power in each radial direction can be measured from the interval between two light spots on each of these radial lines. That is, if the refractive power in the three radial directions is obtained and the change in the radial direction is assumed to be sinusoidal,
An eye refraction value including a spherical power, an astigmatism degree, and an astigmatism angle can be obtained.

Although the above-described embodiment shows the case of a three-diameter wire, it goes without saying that the present invention can be similarly applied to a three-diameter wire or more. Although the case where an array sensor is used as the optical position sensor has been described, an analog optical position sensor such as a semiconductor optical position detector (position detector) may be used.

[0021]

As described above, the eye measuring apparatus according to the present invention measures a point-like light beam projected from the center of the pupil to the fundus, so that the same portion of each meridian fundus can be obtained regardless of the diopter of the eye to be examined. And accurate measurement is possible.

Since the light deflecting member deflects the luminous flux in the pupil away from the optical axis, the two-dimensional optical position sensor surface can be used effectively, and the received luminous flux deviates from the optical position sensor even with strong astigmatic eyes. Can be measured without any problems.

[Brief description of the drawings]

FIG. 1 is an optical configuration diagram of a first example.

FIG. 2 is a front view of an arrangement example of a measurement light source.

FIG. 3 is an explanatory diagram of a relationship between a cylindrical lens and a one-dimensional array sensor.

FIG. 4 is a configuration diagram of a second example.

FIG. 5 is a front view of a cylindrical lens plate.

FIG. 6 is a side view.

FIG. 7 is an explanatory diagram of light spots on an area array sensor.

FIG. 8 is a configuration diagram of an embodiment.

FIG. 9 is a front view of a cylindrical lens plate.

FIG. 10 is an explanatory diagram of a relationship between an array sensor and a light spot.

FIG. 11 is a front view of a 6-hole aperture.

FIG. 12 is a front view of a prism plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 12, 21 Aperture 7a-7f Measurement light source 13, 18 Cylindrical lens plate 19 Two-dimensional area array sensor 10, 17 Dichroic mirror 20 Perforated mirror 23 Light source for refraction measurement 24 Six-hole aperture

Claims (1)

[Claims] 1. A two-dimensional optical position sensor receives a projection system for projecting a point light beam from the center of the pupil to the fundus of the eye to be inspected, and receives a reflected light from the periphery of the pupil via a light deflecting member provided substantially conjugate with the pupil. An eye measurement device, comprising: a light receiving system that deflects a light beam from each part around the pupil in a direction away from the optical axis.