JPS5897340A - Apparatus for aligning position of ophthalmic machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positioning apparatus for ophthalmological equipment, and more particularly to a positioning apparatus capable of simultaneously adjusting the working distance and alignment of an eye to be examined and ophthalmological equipment. Furthermore, the present invention relates to a positioning device directed toward automation of adjustment.

Today, ophthalmologists use ophthalmological equipment such as bottom cameras, refractometers (II and 1), and keratometers. It is necessary to perform adjustment in the axial direction (working distance adjustment) and adjustment in a plane perpendicular to the optical axis (alignment adjustment).

Conventionally, Japanese Patent Publication No. 56-5533 is known for using iris reflection to align ophthalmological equipment with the subject's eye. It's not something you do.

Furthermore, in the specification of Japanese Patent Application No. 55-87081, which is an earlier application filed by the present applicant, a nine-position alignment device that also uses iris reflection is described, but the amount of light reflected from the iris is small and noise from corneal reflection is incorporated. As a matter of fact, a sufficiently stable signal can be obtained.

On the other hand, as one that uses corneal reflex rather than iris reflex,
U.S. Patent No. 3,864,030, 4I11, 1983-
No. 52730 is known, but the former has a movable part and has a complicated structure, and the latter has the problem that only alignment adjustment is possible and working distance adjustment is not possible at the same time.

It is an object of the present invention to provide an alignment device that can be automatically aligned. In order to achieve this object, the present invention is characterized by having two light receiving systems that detect corneal reflected light obliquely to the optical axis of the ophthalmological equipment.

Hereinafter, the present invention will be described in detail using the accompanying drawings.

FIG. 1 is a diagram of a jlil embodiment of the invention. The light emitted from the light source or the finger Iil illuminated by the light source becomes a parallel infinite beam of light through the objective lens 2 and the ophthalmology flAl optical device X, and the subject I.
Irradiate the cornea Ee of IE. Here, a corneal reflected image 1' (imaginary) is formed due to the convex mirror action of the cornea He, but the corneal reflected image 1' is the corneal E regardless of the absolute position of the eye E.
It is formed at a constant position relative to c. The reflected light from the cornea Ee comes out as if from the corneal reflection image 1',
The light enters two sets of light receiving systems installed at an angle with respect to the optical axis 2.

The light receiving system consists of lenses 3m and 3b and split light receiving elements 4m and 4, respectively.
Consists of b.

Although each of the divided light-receiving elements 4a and 4b is preferably a four-divided light-receiving element, for convenience, the description will be made first as a two-divided light-receiving element.

Divided light-receiving element 4m, the dividing boundary of the center, that is, 4a,
The boundary line between and 4b, and 4- is on the chief ray connecting the corneal reflection image 1' and the pupil center of the lenses 3a and 3b.

Here, the corneal reflection image 1' and the divided light receiving elements 4m and 4b do not need to be optically conjugate to the lenses 3a and 3b.

If a conjugate-successive relationship is used, the light spot will become smaller, and the area of the light beam occupied by each element of the divided light-receiving element will be small, which will be inconvenient for measurement.

Now, when the eye to be examined is in the normal position as shown by the solid line in Fig. 1, the corneal reflected light is divided into the divided light receiving elements 4m and 4b as shown in Fig. 2 (4).
, 4b, so that the received light outputs are balanced.

Here, if the eye to be examined is shifted parallel to the optical axis 2 of the measurement system as shown in )K in FIG.
The light flux incident on 4b is shifted in the same direction. That is,
Compared to the output of element 4at t 4b1, element 4aa,
4bt output becomes high. Insufficient alignment adjustment is detected from this unbalanced state of the output, and the relative position with the eye to be examined is adjusted so that the output is balanced.

If the test object @E is shifted in the two directions of the optical axis and is at the position shown by the broken line, that is, the working distance adjustment is inadequate.As shown in Figures 1a and 2, the incident light flux to the split light receiving elements 4ae and 4b will be in the opposite direction. 0 to shift, that is, the output of element 4& is higher than the output of element 4, and the output of element 4th is lower than the output of element 4h. 0 From this output imbalance state, a working distance adjustment deficiency is detected, and the output The relative position with respect to the eye to be examined in the optical axis direction is adjusted so that the eye is oriented.

In this way, each of the divided light receiving elements 4m and 4b is
- Also, when the outputs of 4bl and 4bt are adjusted to be equal, the relative position between the eye E and the objective lens 2 can be determined. Nine embodiments have been described using the above, but in this case, regarding alignment adjustment, only alignment in the plane of the paper is possible, and alignment perpendicular to the plane of the paper cannot be performed.
By using a 4-split light-receiving element as shown in the figure, alignment not only in the in-plane direction but also in the direction perpendicular to the plane of the paper is possible.In other words, for alignment adjustment in the in-plane direction, (51Lt + Sag) t (5at + 5
114)l (5bs+5bs)-(5bt+
5b4) are each 4asw 4ate 4bl g 4
This corresponds to B.

, odd - (5bs + Sba) becomes the element to be compared.
The output of am) is higher than the output of (5ml + 5a4), and similarly the output of K (5bt + 5bt) is higher than that of (Sb
s +5b4).

Regarding the working distance adjustment, (sa', + sag
)*(5at+5aa) I (5bt+5ba)
e (5 bt + 5 ha) will be used as the element to be compared0 Figures 4 (4) and (6) show the second embodiment of the present invention. Figure (6) shows a horizontal cross section. This differs from the first embodiment in that two detection systems are provided obliquely within the horizontal plane.
It is assumed to be an infinite beam of light oblique to the optical axis 2 of the limited medical device,
A corneal reflection image 6' of the light source 6 is formed by the convex mirror action of the zero angle 114Fje irradiating the eye E to be examined, and the chief ray 8 of the corneal reflection is incident on the lens 11 shown in FIG. Here, the principal ray 8 coincides with the optical axis of the lens 10, and the center position of the light receiving element 11 is on the optical axis of the lens 10.

The illumination to the subject IIE is an infinite beam, the corneal reflection principal ray is rounded parallel to the optical axis 2 of the limited medical instrument, and the corneal reflection image is at a constant position with respect to the angle 1IEe regardless of the absolute position of the subject IIE. .

As mentioned above, it is preferable that the light receiving elements are shifted from each other in terms of the division plan, since the irradiation area can be increased.

As shown in Figure 4 @, the main light I/s8 in the horizontal section
m, 8b ti ophthalmology@@12 objective lens 90 optical axis 2
Lenses 10m, 10b, and four-split or two-split light-receiving elements 11a, llb are provided corresponding to the principal rays 8m, 8bK.

When the alignment and working distance are adjusted, the principal ray 81.8b from the corneal reflection image 6' is set to go toward the center of the light receiving elements 11a and 11b. If the alignment adjustment is incorrect, for example, if the subject's eye shifts upward in the horizontal plane as shown in Fig.
1m, llb 1 in the same direction with respect to K, that is, both shift downward.

Furthermore, if the working distance adjustment is poor, for example, as shown in Figure 4), if the subject's eye is shifted toward the front of the normal position in the optical axis direction, the principal rays from the corneal reflection 66/ That is, it is shifted upward with respect to the light receiving element 11m and downward with respect to the light receiving element 11b.

By the way, although Figure 4 (5) is a vertical cross section and Figure 4 (忤) is a horizontal cross section, it is the opposite system, that is, Figure 4 (4) is a horizontal cross section and Figure 4 (2) is a vertical cross section. It's okay.

By the way, as described above, the light-receiving element is a split light-receiving element, and the alignment and working distance are adjusted based on the light intensity balance. It may be possible to detect a deviation of the position from the element center position. In the case of a split light-receiving element, it is desirable to provide the light-receiving element at a position shifted from the conjugate position of the lens of the corneal reflection image in order to increase the irradiation area, but in the case of a position detector such as a position detector, it is preferable to provide the light-receiving element at a position shifted from the conjugate position of the lens of the corneal reflection image. Providing it at a conjugate position has a smaller irradiation area and better measurement accuracy.

Further, in the present invention, the lens 3a, 3b or 10
A and 10b are used to condense light, but a pinhole or the like may be provided instead of a lens so that the light beam always passes through a fixed position.

Although the indicator 1 may be a light source itself, using an infrared light source such as an infrared diode can better prevent miosis of the eye to be examined.

By using the present invention, alignment adjustment 1 and chewing distance adjustment can be automatically performed using the output of the light receiving element, for example, the photoelectric output.

As described above, according to the present invention, it is possible to provide a positioning device for ophthalmological equipment that has no movable parts and can be automatically closed.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the first embodiment of the present invention, and Fig. 2 (4))((
')/Ii In the relationship diagram between the two-split light receiving element and the luminous flux, each
The figure shows alignment adjustment and operating pressure 1I11! The correct state of IJI, Fig. 2 [F]) shows the state where the alignment adjustment is incorrect, Fig. 2 C shows the state where the working distance adjustment is incorrect, and Fig. 3 is a diagram showing the relationship between the 4-split light receiving element and the luminous flux. , Figure 4) is a diagram of the second embodiment of the present invention, in which the EFi subject's eye,
& is the cornea, X is the optical axis of the ophthalmological equipment, 1.6 is the index (light source),
a9 is objective lens, 3m, 3b, 7.10a, 1
0b is a lens, 4a+ 4b is a two-part light receiving element, 8a+
8b is the corneal reflection chief ray, 5ae 5be11a, l
lb is a four-part light receiving element. Applicant Canon Co., Ltd.

Claims (1)

[Claims] 1. Projecting an index onto the subject @, receiving light from the corneal reflection image of the index with a light receiving element, and aligning the eye to be inspected with respect to the ophthalmological equipment based on the position of the light beam on the light receiving element. The device has two light-receiving optical systems that take out corneal reflected light obliquely to the optical axis of the ophthalmological equipment, and alignment adjustment and working distance adjustment are performed based on the light flux position state on the two light-receiving elements of the light-receiving optical system. A positioning device for ophthalmological equipment characterized by the following. 2. A claim in which the two light-receiving optical systems each have a projection lens, and the center position of the light-receiving element is set on the chief ray from the corneal reflected image position when the eye to be examined is in a normal position. 2. The positioning device for ophthalmological equipment according to item 1. 3. The positioning device for ophthalmological equipment according to claim 2, wherein the light receiving element is a two-divided or four-divided light receiving element. 4. The positioning device for ophthalmological equipment according to claim 3, wherein the light receiving element is provided at a position shifted from the conjugate position of the corneal reflected image on the optical path by the projection lens. 5. The ophthalmological equipment positioning device according to claim 2, wherein the index is irradiated onto the subject's eye as an infinite light beam parallel to the optical axis of the ophthalmological equipment. 6. The index is irradiated onto the subject's eye as an infinite beam of light obliquely to the optical axis of the ophthalmological device, and the chief ray from the corneal reflection image coincides with the optical axis of the projection lens. The positioning device for ophthalmological equipment according to item 2. 7. The positioning device 0 for an ophthalmological device according to claim 7, which is provided at a conjugate position with an alignment lens for an ophthalmological device according to claim 2, wherein the light receiving element is a positive position sensor.