JPS627290Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a biological tissue observation optical device.

In biological tissue, for example, the back surface of the cornea of the human eye, there is a cell membrane consisting of tortoise shell-shaped cells approximately 20 microns in size called corneal endothelial cells. This cell membrane plays a major role in maintaining the transparency of the cornea.
The importance of observing and photographing living organisms is being emphasized. By the way, like the corneal cortex, the corneal endothelial cell membrane is transparent and has a small contrast difference with the surrounding area, so it is difficult to observe it with a general microscope, etc., and a special illumination observation method is used.

That is, the illumination optical system and the observation optical system are partially shared, and a light splitting mirror is arranged within the observation optical system to introduce the illumination light flux. In addition, in this type of optical device, in order to prevent ghosts caused by reflections on the corneal surface, a tip lens made of a transparent material is placed at the tip of the illumination optical system and observation optical system, and this tip lens is attached to the corneal surface. The object is brought into contact with the object directly or through a liquid, and illumination observation is performed through this tip lens. Physiological saline or a corneal protective medium is used as this liquid, and its refractive index is 1.33, which is approximately equal to the refractive index of the cornea, 1.376. When a corneal protective medium is used, since the difference in refractive index between the cornea and the corneal protective medium is small, reflection at this boundary is small and does not pose a problem in practice. However, reflection occurs at the interface between the tip lens (refractive index approximately 1.5) and the corneal protective medium. This harmful reflected light does not form an image on the imaging plane of the corneal endothelial cell image, but since the working distance of this type of optical device is short, around 1 mm, when the cornea is observed using the observation optical system, the corneal endothelium An image due to the reflected light appears near the image. Therefore, when the width of the slit illumination light is increased, the corneal endothelium image and the reflected image of the slit illumination light from the interface between the tip lens and the corneal protective medium overlap, and the resolution contrast of the corneal endothelium image deteriorates significantly. do.

Incidentally, various proposals have been made to prevent harmful reflected light from entering the observation optical system from the interface between the tip lens and the corneal protection medium.
The first proposed example is constructed by adhesively bonding a tip lens divided into two parts along the optical axis with an opaque layer interposed therebetween, and illuminating through one divided member and observing through the other divided member. The manufacture of this tip lens involves difficult operations such as cutting the lens and bonding through an opaque layer, and the adhesive used for bonding may have an adverse effect on the eyeball. In the second proposed example, the distal lens is composed of two members cut along a plane perpendicular to the optical axis, and the member on the eye side is arranged between the refractive index of the corneal protective medium and the refractive index of the other member. By selecting and configuring the material to have a refractive index, light reflected by the interface between the tip lens and the corneal protective medium is reduced. However, the refractive index value of transparent materials that can be used as tip lenses is limited, and the reality is that the reflected light is only slightly reduced compared to conventional lenses.

The purpose of the present invention is to provide a biological tissue observation device that solves the above conventional problems. In a biological tissue observation optical device that performs illumination and observation through a lens, at least a part of the subject's eye of the tip lens has a planar shape along the optical axis for reflecting harmful light on a plane parallel to the optical axis. This is because an air layer is provided. By configuring this invention in this way,
It is easy to manufacture and can almost completely prevent light reflected by the interface between the corneal protective medium and the tip lens from being reflected by the air layer and entering the observation optical system.

Embodiments of the present invention will be described below based on the drawings. In the first embodiment, as shown in FIG.
It is constructed by providing a planar air layer 8 along the . This air layer 8 may be formed by forming a groove in the tip lens 2 along the optical axis. This tip lens 2 is attached to the cornea 1 of the eye 4 to be examined.
0 with a corneal protective medium 11 interposed therebetween. Behind the tip lens 2, a common objective lens 12 for the observation optical system and the illumination optical system and a light splitting mirror 14 for introducing illumination light are arranged. With this arrangement, the slit light flux from the illumination optical system is reflected by the illumination light introduction light splitting mirror 14, passes through the objective lens 12 and the lower half of the tip lens, and is aligned with the optical axis of the objective lens 12. It is projected toward the subject's eye 4 at a predetermined angle to form a slit image on the corneal endothelial cells on the back surface of the cornea. The thus illuminated corneal endothelial cells are observed by an observation optical system through the upper half of the tip lens 2 and the objective lens 12. At this time, the reflected light generated at the interface between the tip lens 2 and the corneal protection medium 11 is prevented from entering the observation optical system by being reflected at the interface with the air layer due to the difference in refractive index between the tip lens material and the air. can.
Furthermore, if the surface of the groove forming the air layer 8 is polished, the light is totally reflected, and it is possible to more completely prevent the light from entering the observation optical system.

In the second embodiment, as shown in FIG. 2, the distal end lens 20 is made by adhesively or mechanically joining members 22 and 24 configured such that the tip lens 20 is divided into two parts along a plane including the optical axis. Grooves 28 and 30 forming a planar air layer 26 along the optical axis are provided on the eye side of the members 22 and 24 forming the tip lens 20. Note that even if the above-mentioned bonding is performed using an adhesive, since the adhesive does not come into direct contact with the corneal protective medium, there is no risk that the adhesive will have an adverse effect on the eyeball.

In the third embodiment, as shown in FIG. 3, members 32 and 34 are arranged such that a tip glass 30 is divided into two parts along a plane including the optical axis, with an air gap 36 between them.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the first embodiment, FIG. 2 is an explanatory diagram of the second embodiment, and FIG. 3 is an explanatory diagram of the third embodiment. 2...Tip lens, 4...Eye to be examined, 6...Optical axis, 8...Planar air layer, 10...Cornea, 11...
Corneal protection medium, 14... Light splitting mirror for introducing illumination light, 20... Tip lens, 30... Tip lens.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. In a biological tissue observation optical device in which a tip lens is disposed at the tip of a microscope system and illumination and observation are performed through the tip lens, at least a part of the tip lens on the subject side An optical device for observing biological tissues, characterized in that a planar air layer is provided along the optical axis for reflecting harmful light on a plane parallel to the optical axis. 2. The biological tissue observation optical device according to claim 1, wherein the tip lens is formed of a single member, and the single member is provided with a groove to form the air layer. 3. The biological tissue observation optical device according to claim 1, wherein the tip lens is composed of two members, and the two members are joined together so as to have an air layer. 4. The biological tissue observation optical device according to claim 1, wherein the tip lens is composed of two members, and the two members are arranged so as to constitute an air layer.