JPS6125762Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a microscope for magnifying observation or photographing the inside of the eyeball.

In this type of microscope, an optical glass member provided at the tip of the objective lens is brought into contact with the cornea of the eyeball, and illumination light is guided into the eyeball by moving backward through the objective lens from a direction inclined to the optical axis. , it is common practice to focus an optical system on the area to be examined and take an observation or photograph.

FIG. 1 shows an example of the configuration of such a microscope, in which illumination light emitted from a light source 1 passes through a condensing lens 2 and a slit 3, and is collimated by a lens 4.
The light enters the lower half of the objective lens 6 retrogradely by the reflecting mirror 5, passes through the cone lens 7 within the objective lens 6, and illuminates the test site within the eyeball 8. The optical image of the area to be examined passes through the upper half of the objective lens 6 again and is imaged on the photosensitive plate 10 by the imaging lens 9, or after passing through the imaging lens 9, it is formed by a semi-transparent mirror or a movable reflector. After passing through a mirror 11, the image is magnified and observed through an eyepiece 12. Conventionally, cone lens 7
Alternatively, it has been common practice for a disc-shaped, cylindrical, etc. tip optical member to be brought into direct contact with the cornea of the eyeball, or to face it through an extremely thin layer of immersion liquid.

FIG. 2a is an enlarged view of the optical path inside the cone lens 7 when the cornea 13 of the eyeball 8 is brought into direct contact with the cornea 13 as described above. illumination light
L ₁ and L ₂ illuminate a region having a width D, and an optical image of that region is obtained by image lights S ₁ and S ₂ . Therefore, originally, it should be possible to photograph or enlarge the entire range over the width D. However, since the optical refractive index of the vitreous material constituting the cone lens 7 and the cornea 13 are considerably different, reflected lights R ₁ and R ₂ are generated at the contact interface 14, and this reflected light becomes the image beam of the examined region. Since the brightness reaches about 10 times that of the brightness of , it is difficult to photograph or observe most of the width D.
Therefore, the width that can actually be photographed and observed is the width W.
is only a narrow range corresponding to 20 to 25% of the width D, and the field of view observed by the eyepiece 12 is as shown in Fig. 2b.
It was like that. Also, cone lens 7 and cornea 1
In some cases, a thin layer of immersion liquid was interposed between the two and the three, but there was no significant difference in the condition of the inspection field even in that case.

The inventor first formed the rear part of the cone lens 7 from optical glass, and formed the front part from a solid material with a low refractive index such as fluorite, and created an immersion liquid layer between the cornea of the eye and the front part. By arranging the cone lens and changing the refractive index sequentially from the rear part of the cone lens to the cornea, he invented a method to reduce the reflection of illumination light at the contact interface and reduce the loss of the image ray to be examined. Filed patent application No. 56560.

However, the microscope disclosed in the above-mentioned patent application requires the formation of an immersion liquid layer, which is troublesome for infant examinations and animal experiments. However, subsequent research has shown that the microscope of the above patent application suffers from much more interference due to reflection of illumination light than conventional microscopes that use optical glass for the tip optical member, even when used without an immersion liquid layer. Because the amount of water is small, it is very practical, and since the cornea properties of rabbits and cats are different from humans, we discovered that test results that are not significantly different from those obtained when an immersion liquid layer is provided are obtained. This idea is
Based on this discovery, the objective is to realize a microscope that is easy to operate and is particularly suitable for examining the eyeballs of infants and animals, and this will be explained below based on the embodiment shown in the third figure.

Reference numeral 15 denotes an eyepiece lens barrel, and a cone lens 16 protruding from the tip thereof has a rear portion 17 made of optical glass and a front portion 18 made of a transparent solid material with a low refractive index. Fluorite and certain plastics are suitable as such low refractive index materials.

Optical glasses generally have a refractive index of 1.5 or more, whereas fluorite has a refractive index of 1.43 and the cornea has a refractive index of 1.37. Therefore, between the cone lens posterior portion 17 made of optical glass and the cornea 13, there is provided a fluorite anterior portion 1 having a refractive index that is located exactly between the two.
8, it becomes possible to observe and photograph the test site with a wide field of view during infant tests and animal experiments, and the trouble of providing an immersion liquid layer can be avoided.

[Brief explanation of the drawing]

Fig. 1 is a general optical path diagram of an ophthalmic microscope, Fig. 2 is an explanatory diagram of the relationship between the illumination reflected light and the image ray at the contact surface of the objective lens, and Fig. 3 is an illustration of the objective lens in an embodiment of this invention. FIG. 8... Eyeball, 13... Cornea, 15... Objective lens barrel, 16... Cone lens (tip optical member), 17... Back portion, 18... Front portion.

Claims (1)

[Scope of utility model registration request] The objective lens includes a distal optical member whose distal end surface is in contact with the eyeball to be examined, and the distal optical member has a rear portion opposite to the eyeball to be examined formed of glass, and a rear portion on the opposite side from the eyeball to be examined. An ocular microscope, the front part of which is made of a transparent solid material having a refractive index between that of the glass and the cornea of the eye to be examined.