JP3056799B2 - Ophthalmic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus, and particularly to a high precision in alignment between an eye to be examined and an ophthalmic apparatus, that is, setting of a predetermined positional relationship between the two, as in an intraocular pressure measuring apparatus. It relates to the required ophthalmic device.

[0002]

2. Description of the Related Art There is known an intraocular pressure measuring apparatus which measures an intraocular pressure by injecting a fluid onto a corneal surface and measuring a time until a corneal applanation or a pressure signal when a corneal deformation detection signal is maximized. (Japanese Patent Application No. 1-192331, Japanese Patent Publication No. 63-58577). In this device, an airflow generated by a predetermined pressure is blown to the center of the cornea of the eye to be examined, and the intraocular pressure is calculated from the time until the cornea is deformed into a plane or the pressure signal when the corneal deformation detection signal is maximized. calculate. Whether or not the cornea has been applanated is determined by the fact that the amount of light received by a light receiving element that receives light from a light source such as an LED via a lens is maximized.

[0003] In this case, if the tonometry device and the eye to be examined are not exactly in a predetermined positional relationship, a measurement error becomes large.
An alignment detecting optical system for detecting whether or not the positional relationship is established is provided, and is incorporated in the apparatus in a predetermined positional relationship with the measuring optical system. In the conventional configuration, as an alignment detection optical system, a projection optical system for projecting an alignment detection index on the vertex of the corneal surface of the eye to be inspected, and a reflected light flux of the index from the eye to be inspected when the alignment is correct There is provided only one alignment detection optical system including a light receiving optical system for receiving and detecting the light.

[0004]

However, when the eye to be examined is slightly deviated from a predetermined alignment position during the alignment detection in the above-mentioned conventional ophthalmologic apparatus, a part of the reflected light from the eye to be examined is detected. Is incident on the light receiving optical system, and a certain amount of output is obtained from the light receiving element, which makes it difficult to accurately determine whether or not the alignment is correct.

An object of the present invention is to enable the above-described alignment detection to be performed more strictly and accurately in this type of ophthalmologic apparatus.

[0006]

According to the present invention, there is provided an ophthalmologic apparatus for performing the above-described alignment detection, wherein a projection optical system for projecting an alignment detection index onto a predetermined portion of an eye to be examined. And a plurality of alignment detection optical systems including a light receiving optical system that receives and detects reflected light of the projection light of the target from the subject's eye when alignment is performed, and performs alignment using the plurality of alignment detection optical systems. A configuration that performs detection is adopted.

[0007]

According to such a configuration, by performing alignment detection in a multiplex manner by a plurality of alignment detection optical systems, the detection can be strictly and accurately performed.

[0008]

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows an alignment detection optical system provided in an ophthalmologic apparatus according to an embodiment of the present invention and for detecting alignment between the above-described eye and the apparatus.

In FIG. 1, an LED (light emitting diode) 8 as a light emitting element, a pinhole plate 6 in which a pinhole is formed, a half mirror 4, a taking lens 2 and an objective lens 1 are applied to a vertex 16 of a cornea 15 of an eye 14 to be examined. A first projection optical system that projects the alignment detection target is configured.

An objective lens 1, a taking lens 3,
When alignment is performed by a light receiving element (photoelectric conversion element) 13 including a pinhole plate 11 and a photodiode, the reflected light of the index projected by the first projection optical system is received to detect alignment. A first light receiving optical system for obtaining an output is configured. The first light receiving optical system and the first projection optical system constitute a first alignment detecting optical system.

On the other hand, the LED 9, the pinhole plate 7, the half mirror 5, the taking lens 3 and the objective lens 1 similarly constitute a second projection optical system for projecting an alignment detection index onto the subject's eye 14. . A second light receiving optical system that receives the reflected light of the index projected by the second projection optical system and obtains an alignment detection output by the objective lens 1, the taking lens 2, the pinhole plate 10, and the light receiving element 12. The system is configured. Then, the second light receiving optical system and the second projection optical system constitute a second alignment detecting optical system. That is, in the ophthalmologic apparatus of the present embodiment, two alignment detecting optical systems are provided.

Next, the alignment detecting operation according to the above configuration will be described. At the time of alignment detection, first, the LE 1 is set in a state where the objective lens 1 faces the subject's eye 14 whose face is fixed by a chin rest (not shown) of the apparatus and a forehead rest.
D8 and D9 are turned on.

The light emitted from the LED 8 passes through the pinhole of the pinhole plate 6, and after the optical path is bent by the half mirror 4, is irradiated on the vertex 16 of the cornea 15 of the eye 14 by the taking lens 2 and the objective lens 1. , An image of an index having a shape corresponding to the pinhole is formed. The light of the target image is reflected by the cornea 15 and passes through the half mirror 5 by the objective lens 1 and the taking lens 3 before being formed on the pinhole 11 plate. If the eye 14 and the apparatus are correctly aligned, the position of the image coincides with the pinhole of the pinhole plate 11, and the light is incident on the light receiving surface of the light receiving element 13 through the pinhole, A detection output indicating that the alignment is achieved is obtained.

Here, for convenience of explanation, the above-mentioned detection output is indicated by two values of "1" and "0", and the detection output indicating that the alignment is correct is "1". The output shown is “0”.

On the other hand, the light emitted from the LED 9 passes through the pinhole of the pinhole plate 7, and after the optical path is bent by the half mirror 5, the light is emitted onto the vertex 16 of the cornea 15 of the eye 14 by the taking lens 3 and the objective lens 1. The target is illuminated and an image of the target is similarly formed. The light of the target image is reflected by the cornea 15, and the objective lens 1 and the taking lens 2
After passing through the half mirror 4 by the pinhole plate 1
Image on 0. As described above, if the alignment of the eye 14 and the apparatus is correctly aligned, the position of the image coincides with the pinhole of the pinhole plate 10, and the light passes through the pinhole and strikes the light receiving surface of the light receiving element 12. A detection output of “1” which is incident and indicates alignment is obtained.

In this embodiment, the outputs of the light receiving elements 12 and 13 are ANDed (logical product), and the resulting output is used as the final detection output. Thereby, alignment detection can be performed strictly.

For example, when the subject's eye 14 is slightly deviated from a predetermined alignment position, a part of the reflected light of the projection target by the first projection optical system below the LED 8 is used as the light receiving element 13 of the first light receiving optical system. However, the reflected light of the projection target by the second projection optical system below the LED 9 may not enter the light receiving element 12 of the second light receiving optical system.

In this case, even if the output of the light receiving element 13 is "1", the output of the light receiving element 12 is "0" and the AND is "0", that is, the final detection result is not aligned. Will be shown.

Conventionally, there is only one alignment detecting optical system. In the above case, only the first projection optical system and the first light receiving optical system provide a detection output of "1" and achieve alignment. May be detected.

That is, in the prior art, even if the alignment is slightly deviated, it may be detected that the alignment is correct. In the case of this embodiment, however, the alignment is strictly accurate and the first and second alignments are performed. The reflected light of the projection index of the projection optical system is accurately incident on the light receiving elements 13 and 12 of the first and second light receiving optical systems, and the outputs of both elements 13 and 12 are both “1”.
Only when it becomes, the detection output becomes “1”, and a match of the alignment is detected.

As described above, according to the present embodiment, the alignment detection is performed twice by the two alignment detection optical systems, so that the alignment detection can be performed strictly and accurately, and the alignment can be performed accurately. In the case of the device, the intraocular pressure can be measured accurately.

In the above configuration, if the emission wavelengths of the LEDs 8 and 9 are the same, and both are turned on at the same time and the detection by the two alignment detecting optical systems is performed simultaneously,
Detection may be hindered by interference between the projected light beam and the reflected light beam of the two optical systems.

To avoid this interference problem, an LED
It is sufficient that the wavelengths of the light emissions 8 and 9, that is, the wavelengths of the projection light of the indexes of the first and second projection optical systems are different. Further, even if the wavelength of the projection light is the same, the timing of the light emission of the LEDs 8 and 9 may be shifted so that the detection by the first and second alignment detecting optical systems is performed before and after.

The projection light from the LEDs 8 and 9 is desirably infrared light so that the subject is not dazzled. The light source of the projection optical system is not limited to the LED, of course.

In the above configuration, two alignment detection optical systems are provided. However, three or more alignment detection optical systems may be provided.

[0026]

As is apparent from the above description, according to the present invention, there is provided an ophthalmic apparatus for detecting whether or not a subject's eye and an ophthalmic apparatus have a predetermined positional relationship.
A projection optical system for projecting an alignment detection index onto a predetermined portion of the eye to be inspected; and a light receiving optical system for receiving and detecting the reflected light of the projection light of the index from the eye when the alignment is correct. A plurality of alignment detection optical systems are provided, and a configuration is employed in which alignment detection is performed by the plurality of alignment detection optical systems. Therefore, alignment detection can be performed in a multiplexed manner to accurately and accurately perform alignment, thereby achieving accurate alignment. An excellent effect is obtained in that measurement, observation, photographing, and the like relating to ophthalmology can be accurately performed by the ophthalmic apparatus.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an alignment detection optical system of an ophthalmologic apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2, 3 Taking lens 4, 5 Half mirror 6, 7, 10, 11 Pinhole plate 8, 9 LED 12, 13 Light receiving element 14 Eye to be examined 15 Cornea

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61B 3/10 A61B 3/16

Claims (5)

(57) [Claims] 1. An ophthalmic apparatus for performing alignment detection as to whether or not an eye to be inspected and an ophthalmic apparatus have a predetermined positional relationship, a projection optical system for projecting an alignment detection index onto a predetermined portion of the eye to be inspected, A plurality of alignment detecting optical systems including a light receiving optical system that receives and detects reflected light of the projection light of the index from the eye to be examined when alignment is provided, and performs alignment detection with the plurality of alignment detecting optical systems An ophthalmologic apparatus, comprising: 2. The ophthalmologic apparatus according to claim 1, wherein a wavelength of projection light of the index by the projection optical system differs for each of the plurality of alignment detection optical systems. 3. The ophthalmologic apparatus according to claim 1, wherein the alignment detection by the plurality of alignment detection optical systems is performed before and after shifting the timing of index projection of each projection optical system. 4. The ophthalmologic apparatus according to claim 1, wherein projection light of the index of the plurality of alignment detection optical systems is infrared light. 5. The ophthalmologic apparatus according to claim 1, wherein a light source of the projection optical system of the plurality of alignment detection optical systems is a light emitting diode.