JP2001161644A - Optometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately determine the correctness of eyeglasses by measuring the refractive ability of a subject's eyes while the subject is gazing into a distance with both eyes wearing glasses. SOLUTION: The refractive ability is measured while the subject is gazing into a distance with both eyes wearing glasses. When it is recognized that his eyes are set in position, a light source 25 with an intense light is turned on and the light is reflected from the eyeground. If a disturbing light comes in from a path in front of his eyes, the path is blocked with a shutter 16. The light reflected from the eyeground goes through lenses T of the glasses and is reflected from a dichroic mirror 8, 11, through an objective lens 19, from a mirror 20, a pierced mirror 21, through a diaphragm 28, a deflection prism 27, a lens 26, from a dichroic mirror 17 into a means for imaging as luminous flux with a ring shape. The video signal is taken into a means for the arithmetic operation and values of refraction including astigmatism are found from the dimensions and the ovality of the ring. The reflected light of the measured luminous flux, which retraces a path O1 through this lens T, goes along a path O2 and is cut off with a shading material of a film 17a for the total reflection and the refractive ability is accurately measured even if the subject has the glasses with the lens T on.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optometric apparatus used in an ophthalmic hospital or the like.

[0002]

2. Description of the Related Art As a conventional optometry apparatus, an auto-refractometer having a light shielding member at a position conjugate with a spectacle lens in a measurement light receiving optical system is disclosed in Japanese Patent Application Laid-Open No. 62-253027.

[0003]

However, in the above-described conventional auto-refractometer, since the refractive power cannot be measured while wearing a pair of glasses and looking at a distance with both eyes, the correction of the glasses is appropriate. Cannot be accurately determined.

An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide an optometry apparatus capable of accurately measuring the suitability of correcting eyeglasses.

Another object of the present invention is to provide an optometric apparatus capable of performing optometric measurement easily and quickly.

[0006]

According to the present invention, there is provided an optometry apparatus for measuring an eye refractive power by dividing a center and a periphery of a pupil and transmitting a measurement light beam. An optical axis central light shielding member or an optical axis peripheral light shielding member is provided at a position conjugate with the vicinity of the front of the cornea in the projection light receiving optical system.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 shows a configuration diagram of an embodiment, and is a hand-held optometer having both functions of an auto-refractometer and an auto-keratometer. A forehead pad 2 is attached to a left upper end portion of the housing 1 via a spring member 3, and a liquid crystal plate 4 for displaying an anterior eye image to an examiner is attached to a right upper end portion via a hinge 5. ing. When the liquid crystal panel 4 is not used, the liquid crystal panel 4 is housed at a position 4 'indicated by a dotted line by a hinge 5, a projection 6 is provided near the hinge 5, and the liquid crystal panel 4 is positioned at a solid line position. When the display surface is turned upright to the examiner, the switch 6 is pressed by the projection 6 and the power of the apparatus is turned on.

A spectacle lens T worn by the subject is arranged at a position about 15 mm in front of the subject's eye E. The spectacle lens T and a dichroic mirror 8 that transmits visible light and reflects infrared light are provided on the refractive power measurement optical path O1 in front of the subject's eye E.
Is arranged. In the vicinity of the dichroic mirror 8, eight infrared LED light sources 9 are provided around the optical path O1, and these light sources 9 are LEDs with members having a light condensing function, and have a corneal curvature radius. Lighting is used for both measurement and observation of the anterior segment.

On the optical path O2 in the reflection direction of the dichroic mirror 8, as shown in FIG.
Dichroic mirror 11, lens 12, mirror 13, lens 14, mirror 1
5. Shutter 16 having a function of blocking disturbance light entering from the optical path of the anterior segment during refraction measurement, dichroic mirror 17
Are sequentially arranged, and an image pickup means 18 which is a CCD video camera is disposed on an optical path O4 in the left reflection direction of the dichroic mirror 17.

On the optical path O3 in the reflection direction of the dichroic mirror 11, an objective lens 19, a mirror 20, a perforated mirror 21 for branching an imaging optical system and a light receiving optical system for measuring refractive power, and an opening at the center of the optical axis. An aperture 22, a lens 23 conjugate with the pupil of the eye E to be examined, a light-shielding member 24 around the optical axis having a small aperture on the optical axis and conjugate with the spectacle lens T, and a conjugate with the light source 9 and a standard ocular fundus of another wavelength. The infrared LED light sources 25 are sequentially arranged. The infrared LED light source 25 is also used for refractive power measurement and alignment, and forms an image at the focal position of the objective lens 19 by the lens 23.

Further, on the optical path O4 of the light receiving optical system in the rightward reflection direction of the dichroic mirror 17, an objective lens 19 is provided.
A lens 26 that forms an image of the focal position of the light on the imaging element surface of the imaging means 18, a deflecting prism 27 that deflects the light beam outside the optical axis of the optical path O 4, and a ring stop 28 conjugated to the pupil are arranged to reach the perforated mirror 21. .

As shown in the front view of FIG. 2 of the dichroic mirror 11 viewed from the direction of the optical path O2, the dichroic mirror 11 and the lens 12 are long in the direction perpendicular to the plane of the drawing. This dichroic mirror 11 is a wedge prism 1
Except for both end portions where 0 is attached, a thin film that reflects the wavelength light of the light source 25 and transmits the wavelength light of the light source 9 is provided. On the other hand, the wedge prism 10 is provided with a thin film that transmits light of the wavelength of the light source 25 and does not transmit light of the wavelength of the light source 9.

FIG. 3 is a front view of the dichroic mirror 17, in which a central reflection part 17a of the optical axis is provided with a total reflection film made of aluminum or the like. Is applied. The total reflection film of the central portion 17a is conjugate to the spectacle lens T and the light shielding member 24, and has a function of blocking the reflected light of the spectacle lens T and reflecting the alignment light beam coming from the anterior segment optical path. . The size of the light-shielding member 24 is larger than the opening of the light-shielding member 24 by the amount of deflection by the deflection member 27.

With such a configuration, the subject wears the spectacle lens T, and performs the objective refractive power measurement in a state in which both eyes are looking at the outside far away. The examiner holds the lower part of the housing 1 with one hand, and positions the apparatus in front of the subject. When using the device, first raise the liquid crystal panel 4 to the position indicated by the solid line and turn on the power supply to be in a measurable state. After use, the liquid crystal panel 4 is moved to the position indicated by the dotted line 4 so as to approach the housing 1. 'And turn off the power.

The subject wears the spectacle lens T and looks through the dichroic mirror 8 to the outside. At the time of positioning, the light source 9 is turned on, and the anterior eye is illuminated through the spectacle lens T. The anterior ocular segment image is reflected by the dichroic mirror 8 through the spectacle lens T, is reflected by the mirror 13 through the dichroic mirror 11 and the lens 12, is reflected by the mirror 15 and the dichroic mirror 17 through the lens 14, and is imaged. The moving image is displayed on the liquid crystal panel 4 as shown in FIG.

At the time of positioning, the light source 25 is weakly lit because the photographing means 18 receives strong corneal reflected light. The light flux of the light source 25 passes through the light blocking member 24, the lens 23, the aperture 22, and the aperture of the perforated mirror 21, is reflected by the mirror 20, passes through the objective lens 19, and passes through the dichroic mirrors 8, 11.
And is projected on the eye E through the spectacle lens T. The light beam reflected by the cornea of the eye E passes through the spectacle lens T, is reflected by the dichroic mirror 8, passes through the wedge prism 10, passes through the optical path O2 in the same manner as the anterior segment illumination light, and passes through the light of the imaging means 18. An image is formed near the axis as two separate images 25 'as shown in FIG.

If the alignment is greatly deviated, the anterior segment image will not be displayed because the light beam does not hit the central portion 17a of the dichroic mirror 17. The examiner adjusts the alignment and distance from the position of the two images 25 ′ and the degree of separation thereof, and
Positioning is performed so that 5 ′ is aligned with the center of the cross-shaped alignment mark A. The video is sequentially taken into the calculating means, and the signals near the two images 25 'are calculated to calculate the respective image positions. In order to avoid the reflected light of the spectacle lens T, only the upper three light sources 9 may be used for anterior segment illumination. Also, since the spectacle lens T is slightly downward, reflected light is unlikely to occur, but there is no problem in alignment if there is no reflected light at the center of the screen.

When the position is recognized, the light source 25 is turned on so that reflected light from the fundus is obtained.
At that time, if disturbance light enters from the anterior segment optical path, the optical path O2 is blocked by the shutter 16. However, when the anterior segment imaging optical system is dark, the light source 9 may simply be turned off without using the shutter 16.

The fundus reflected light is reflected by the dichroic mirrors 8 and 11 through the spectacle lens T, is reflected by the mirror 20 through the objective lens 19, is further reflected by the perforated mirror 21, and is stopped by the aperture 28, the deflecting prism 27 and the lens. 2
6. The light passes through the dichroic mirror 17 and is received by the imaging means as a ring-shaped light beam. The video signal is taken into the calculating means, and an eye refraction value including astigmatism is obtained from the ring size and the elliptic state.

At this time, the reflected light of the measuring light flux returning to the optical path O1 by the spectacle lens T passes through the optical path O2 and the optical path O2.
The light is blocked by the total reflection film at the central portion 17a of the dichroic mirror 17 serving as the upper light shielding member. In the case of an optometry lens, since it is arranged at the same position as the spectacle lens T, the reflected light is blocked in the same manner, and the objective refractive power can be measured with the optometry lens attached. Therefore, even a subject such as a child who cannot perform a subjective test can easily perform an optometry.

In the measurement of the radius of curvature of the cornea, the spectacle lens T is removed since it is not necessary to perform measurement by putting the spectacle lens T on.
At the time of positioning, similarly to the refractive power measurement, the light source 25 is turned on weakly and the light source 9 is turned on continuously. An image as shown in FIG. 4 is displayed on the liquid crystal plate 4, and the measurement is automatically performed when the positions match.

At the time of measurement, the light source 9 is turned on strongly only for a short time. The frame accumulation time of the NTSC video camera 19 is 3
Since it is 3 mmS, it is lit strongly about 5 mmS in the frame at the time of measurement, and is turned off for the remaining time. If the light intensity is increased by an amount corresponding to shortening the lighting time, a corneal reflection image 9 ′ by the same light source 9 can be obtained.

Since the two images 25 'and the corneal reflection images 9' of the eight light sources 9 are reflected around the center of the screen, this video signal is taken into the arithmetic means, and each of the eight reflection images 9 'is taken. Is calculated to measure the corneal curvature radius. Since the measurement is performed in a short time, accurate measurement can be performed without blurring of the reflected image 9 'due to eye movement or camera shake. The position of the eye E at the time of measuring the corneal curvature radius is known from the position of the second image 25 ', and the correction calculation based on the distance error is performed to accurately measure the corneal curvature. In the present embodiment, since the anterior segment is directly illuminated from the light source 9 without passing through the diffusion member, the light amount is sufficient, and a bright image can be obtained by turning on the light for a short time.

In the above description, the eye E to be examined starts from the center of the pupil.
The optical system projects the measurement light beam into the inside and receives light from the periphery. On the contrary, in the case of an optical system that projects from the periphery and receives light from the center, the light-shielding member 24 conjugated to the spectacle lens T and the center of the dichroic mirror 17 are used. Instead of the light shielding portion 17a, a light shielding member at the center of the optical axis may be arranged in the illumination optical system, and a light shielding member around the optical axis may be arranged in the light receiving optical system.

[0025]

As described above, in the optometry apparatus according to the present invention, the optical axis center light shielding member or the optical axis peripheral light shielding member is provided at a position conjugate with the vicinity of the front of the cornea in the measurement projection light receiving optical system. Thereby, the objective flexure measurement can be performed without being affected by the reflection of the spectacles or the optometry lens.

Further, if the power is turned on and off by taking the display unit in and out, the power operation is facilitated, and the power is not turned off.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optometry apparatus according to an embodiment.

FIG. 2 is a front view near a dichroic mirror.

FIG. 3 is a front view of a dichroic mirror.

FIG. 4 is an explanatory diagram of a captured image of an eye to be inspected.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Forehead contact 4 Liquid crystal board 8, 11, 17 Dichroic mirror 9, 25 Infrared LED light source 10 Wedge prism 16 Shutter 18 Imaging means 21 Perforated mirror 22, 28 Aperture 24 Light shielding member 27 Light deflection member 27 Deflection prism

Claims (2)

[Claims] In an optometry apparatus for dividing the center and periphery of a pupil and passing a measurement light beam to measure an eye refractive power, a central part of an optical axis is shielded at a position conjugate with the vicinity of the front of the cornea in a measurement projection light receiving optical system. An optometry apparatus provided with a member or a light shielding member around an optical axis. 2. The optometry apparatus according to claim 1, wherein a display unit for alignment is provided, and the power is turned on and off by moving the display unit in and out.