JP3106127B2 - 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 provided with alignment means such as a fundus camera and an auto-refractometer.

[0002]

2. Description of the Related Art Alignment means used in conventional ophthalmic machines such as an auto-refractometer generally uses a corneal reflection image of an alignment light source as a "field" different from that used for eye measurement.
An image is formed on a quadrangular photoelectric sensor having a U-shape, and alignment information is obtained based on the light amount balance of the four sensors.

[0003]

However, in the above-mentioned conventional example, since the extra reflected light from the iris or eyelid of the eye to be examined is mixed with the corneal reflected light, the accuracy is reduced.
If an attempt is made to measure only the central portion of the cornea where the corneal reflection image exists by using the photoelectric sensor, it will not be known if the portion deviates from that portion, and a problem will occur in that the detection range is significantly limited.

An object of the present invention is to eliminate the influence of reflected light from the iris and the like of the subject's eye and reflected light from the eyelids generated when the eyelids are closed during alignment, thereby improving alignment accuracy and widening the detection range. An object of the present invention is to provide an ophthalmologic apparatus capable of performing alignment and having a simplified structure.

[0005]

An ophthalmologic apparatus according to the present invention for achieving the above object includes a light source for projecting a light beam so as to generate a corneal reflection image for alignment on an eye to be examined, and a light source for projecting a light beam.
An optical system that forms an anterior ocular segment image including an iris via the optical path in the same direction on the same imaging sensor together with the corneal reflection image, and determines the positions of the two corneal reflection images on the imaging sensor. Detection and alignment are performed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 is a basic principle diagram of the present invention. A half mirror 1, a lens 2, and a television camera 3 are arranged on an optical axis in front of an eye E to be inspected. It is connected. An alignment light source 5 is arranged in the incident direction of the half mirror 1.

The light beam emitted from the alignment light source 5 is reflected by the half mirror 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 the corneal reflection image P is formed on the imaging surface 3 a of the television camera 3 by the lens 2, as shown in FIG. The image of the anterior segment of the eye E and the light source 5
Is projected.

FIG. 3A shows a video signal of a certain scanning line S passing over a corneal reflection image P, and a corneal reflection portion P ′.
Is a strong signal. The reason is that the reflection from the iris, eyelid, and the like of the subject's eye E is diffuse reflection, whereas the reflection from the cornea Ec is spherical reflection.

FIG. 3B shows a signal obtained by binarizing the signal shown in FIG. 3A at an appropriate level indicated by a dotted line. This signal processing is performed by the signal processor 4, and the method may be performed by loading it into a memory and then processing it by software, or processing it by hardware using a circuit. When such processing is performed on all the scanning lines, only the corneal reflection image P remains, and thereafter, the alignment may be performed by detecting the two-dimensional position of the corneal reflection image P.

FIG. 4 shows an embodiment in which the present invention is applied to an auto-refractometer. An objective lens 11, a perforated mirror 12, a central aperture stop 13, a lens 14, a measurement A light source 15 is arranged and a perforated mirror 1
An annular aperture stop 16, a lens 17, a conical prism 18, and an area sensor 19 are arranged on the optical axis L2 in the second reflection direction. Further, lenses 20a and 20b are disposed in two directions obliquely forward of the eye E, and the light beams passing through the respective lenses 20a and 20b from the eye E side are mirrors 21a,
The image is projected onto the area sensor 19 through the area 21b. The members on the optical axes L1 and L2 constitute an auto-refractometer, and the light source 22 for alignment is located above the paper surface of FIG. 4 and is located at a position that does not interfere with the optical path of the auto-refractometer.

The corneal reflection image P from the alignment light source 22 is captured by the lenses 20a and 20b from two directions, reflected by the mirrors 21a and 21b, and projected onto the area sensor 19, as shown in FIG. As described above, two anterior ocular segment images E1 and E2 viewed from two directions and two corneal reflection images P1 and P2 are formed. When only the corneal reflection image P is extracted in the same manner as described above, two corneal reflection images P1 and P2 are obtained.
The distance between the subject's eye E and the apparatus can be determined from the distance of, and the alignment information can be obtained from the deviation from the center.

At the time of measuring the eye refractive power, the light source 22 for alignment is turned off and the light source 15 for measurement is turned on. The light from the measurement light source 15 passes through a lens 14, a central aperture stop 13,
The eye to be inspected E passes through the perforated mirror 12 and the objective lens 11.
Is projected on the fundus of the eye, and the reflected light of the fundus is
, The annular aperture stop 16 on the optical axis L2, the lens 17,
6 through the conical prism 18 and on the area sensor 19.
An annular light beam as shown in FIG. Therefore, the eye refractive power is obtained by analyzing the size and shape of this ring on the area sensor 19. Of course, during alignment, the measurement light source 15 is turned off during alignment, and the area sensor 19 can be shared by time separation between alignment and eye refraction measurement.

Although the above-described embodiment is applied to an auto-refractometer, it goes without saying that it can be applied to a fundus camera and other ophthalmologic devices.

[0014]

As described above, in the ophthalmologic apparatus according to the present invention, since the anterior segment including the iris is imaged on the image sensor through the optical system, alignment can be performed in a wide range, and two directions can be obtained. , The image is formed on the image sensor, so that accurate alignment can be performed.

[Brief description of the drawings]

FIG. 1 is a basic principle diagram.

FIG. 2 is an explanatory diagram of an anterior segment image on an area sensor.

3A is a waveform diagram of a video signal, and FIG. 3B is a waveform diagram of a binarized signal.

FIG. 4 is a configuration diagram of an embodiment applied to an auto-refractometer.

FIG. 5 is an explanatory diagram of an anterior segment image on an area sensor.

FIG. 6 is an explanatory diagram of a refractive power measurement ring on an area sensor.

[Explanation of symbols]

 Reference Signs List 1 half mirror 3 TV camera 3a imaging surface 4 signal processor 5, 22 alignment light source 12 perforated mirror 13 center aperture 15 measurement light source 16 annular aperture stop 18 conical prism 19 area sensor 20a, 20b lens 21a, 21b mirror

Claims (1)

(57) [Claims] A corneal reflection image for alignment is provided on an eye to be examined.
Through a light source that projects the luminous flux to produce
Therefore, the anterior eye image including the iris is the same as the corneal reflection image.
An optical system that forms an image on the imaging sensor of
An ophthalmologic apparatus for detecting and aligning the positions of the two corneal reflection images on a sensor.