JPH02193640A - Ophthalmologic device - Google Patents

Abstract

PURPOSE:To improve the accuracy of alignment and to execute the alignment of a large detection range by removing the influence of iris of an eye to be checked or reflected light from an eyelid at the time of the alignment. CONSTITUTION:A half mirror 1, lens 2 and television camera 3 are arranged on an optical axis in front of an eye E to be checked and the output of the television camera is connected to a signal processor 4. Then, an alignment light source 5 is arranged in the incident direction of the half mirror. Since a light flux from the light source for alignment forms a cornea reflected picture P in the cornea Ec, and when this cornea reflected picture is formed on an image pickup surface 3a of the television camera by the lens, the front eye part picture of the eye to be checked and the cornea reflected picture of the light source are projected on the image pickup surface. In such a case, reflection from the iris or eyelid of the eye to be checked is diffused reflection. However, since the reflection from the cornea is spherical reflection, the video signal of a scanning line S passing on a cornea reflected picture obtains an extremely strong cornea reflected part P'. Then, the two-dimensional position of this cornea reflected picture is detected and the alignment can be executed with the high accuracy over the wide range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ophthalmological apparatus equipped with an alignment means, such as a bottom camera or an autorefractometer.

[Prior Art] Alignment means used in conventional ophthalmological machines such as autorefractometers generally focus the corneal reflection image of an alignment light source on a four-part photoelectric sensor shaped like a square. Although the 7-line information is obtained based on the light intensity balance of the sensor, there is a problem in that accuracy decreases because excess reflected light from the iris, eyelid, etc. of the eye to be examined mixes with the corneal reflected light.

In order to eliminate these drawbacks, if we use a photoelectric sensor to measure only the central part of the cornea where the corneal reflection image exists, there is a problem that the detection range will be severely limited because it will not be visible if the corneal reflection image is outside that part. There is.

[Object of the Invention] The object of the present invention is to eliminate the influence of reflected light from the iris of the subject's eye and reflected light from the eyelids that occur when the eyelids are closed during alignment, and to improve alignment accuracy.
It is an object of the present invention to provide an ophthalmologic apparatus that can perform alignment over a wide detection range.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is to provide an alignment light source that illuminates the eye to be examined, an optical system that projects the corneal reflected image onto an area sensor, and a corneal light source on the area sensor. The ophthalmologic apparatus is characterized in that it has an alignment means for obtaining alignment information by determining the position of a reflected image.

[Embodiments of the invention] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a diagram showing the basic principle of the present invention. A half mirror 1, a lens 2, and a television camera 3 are arranged on the optical axis in front of the eye E, and the output of the television camera 3 is transmitted to a signal processor 4.
It is connected to the. Further, an alignment light source 5 is arranged in the direction of incidence of the half mirror 1.

The light flux emitted from the alignment light $5 is reflected by the two half mirrors 1 and illuminates the eye E to be examined.

Then, a virtual image of the light source 5, that is, a corneal reflection image P is formed on the cornea Ec of the subject's eye E. When this corneal reflection image P is focused on the imaging surface 3a of the television camera 3 by the lens 2, it is shown in FIG. Thus, an anterior segment image of the eye E to be examined and a corneal reflection image P of the light source 5 are projected onto the imaging surface 3a.

FIG. 3(a) shows a video signal of a scanning line S passing over a corneal reflection image P, in which the corneal reflection portion P' is an extremely strong signal. The reason for this is that the reflection from the iris and eyelids of the eye E is diffuse reflection, whereas the corneal E
This is because the reflection from c is a spherical reflection.

FIG. 3(b) shows a signal obtained by binarizing the signal shown in FIG. 3(a) at an appropriate level indicated by a dotted line. This signal processing is performed by the signal processor 4, and the method may be to process it by software after importing it into memory, or by processing it by hardware using a circuit. If such processing is performed, only the reflected image P around the corner 11 will remain, so it is only necessary to detect the two-dimensional position of this corneal reflected image P and perform alignment.

FIG. 4 shows an embodiment in which the present invention is applied to an autorefractometer, in which the optical axis Ll of the eye E is located.

Objective lens 11. Perforated mirror 12, center aperture diaphragm 13
, a lens 14, and a measuring light source 15 are arranged, and on the optical axis L2 in the reflection direction of the perforated mirror 12, an annular aperture diaphragm 16,
Lens 17, conical prism 18. An area sensor 19 is arranged.

In addition, a lens 20a is provided in two diagonal front directions of the eye E to be examined.
20b are arranged, and each lens 2 is placed from the eye E side to be examined.
The light beams that have passed through 0a and 20b are projected onto the area sensor 19 via mirrors 21a and 21b. Optical axis L1. The members on L2 constitute an autorefractometer, and the light source 22 for alignment is located above the plane of the paper in FIG. 4 at a position that does not interfere with the optical path of the autorefractometer.

The corneal reflection image P of the alignment light source 22 is captured by lenses 20a and 20b from two directions, and mirrors 21a and 2
1b and projected onto the area sensor 19, as shown in FIG.
P2 is imaged.

If only the corneal reflection image P is extracted in the same process as in the above embodiment, the distance between the eye E and the device can be determined from the interval between the two anterior segment images E1 and E2, and alignment information can be obtained from the deviation from the center. can get.

When measuring eye refractive power, the alignment light source 22 is turned off, and the measurement light source 15 is turned on. The light from the measurement light source 15 passes through the lens 14, the central aperture 13, the perforated mirror 12, and the objective lens 11, and is projected onto the fundus of the eye E to be examined, and the fundus reflected light is reflected by the perforated mirror 12. Annular aperture stop 16 on optical axis L2. An annular light beam as shown in FIG. 6 is projected onto the area sensor 19 through the lens 172 and the conical prism 18. Therefore, area sensor 19
The eye refractive power can be determined by analyzing the size and shape of this ring above. Of course, the measurement light source 15 is turned off during alignment, and the area sensor 19
can be used in common by separating the time between alignment and eye refraction measurement.

Although the above embodiment is applied to an autorefractometer, it goes without saying that it can also be applied to fundus cameras and other ophthalmological equipment.

F. Effects of the Invention As explained above, the ophthalmological device according to the present invention can eliminate the influence of reflected light from the iris, eyelid, etc. of the subject's eye during alignment, and therefore can improve the accuracy of alignment.
Furthermore, it is possible to perform alignment with a large detection range.

[Brief explanation of the drawing]

The drawings show an embodiment of the eye 1 (device) according to the present invention; FIG. 1 is a diagram of the basic principle, FIG. (b) is a waveform diagram of the binary signal, FIG. 4 is a configuration diagram of an embodiment applied to an autorefractometer, and FIG. 5 is an explanatory diagram of an anterior segment image on an area sensor. FIG. 6 is an explanatory diagram of the refractive power measuring ring on the area sensor. Reference numeral 1 is a half mirror; 13 is a television camera; 3a is an imaging surface; 4 is a signal processor; 5 and 22 are alignment light sources; is a perforated mirror, 13 is a center aperture, 15
1 is a measurement light source, 16 is an annular aperture stop, 18 is a conical prism, and 19 is an area sensor. 20a and 20b are lenses. It is ra.

Claims (1)

[Claims] 1. It has an alignment light source that illuminates the eye to be examined, an optical system that projects the corneal reflection image onto the area sensor, and an alignment means that obtains alignment information by determining the position of the corneal reflection image on the area sensor. An ophthalmological device featuring: