JPH0679106B2 - Image scope - Google Patents

Description

TECHNICAL FIELD The present invention relates to an image scope used for medical inspection, various inspections in industry, and the like.

[Prior Art] Conventionally, various fiber scopes for medical inspections, industrial inspections, etc. have been manufactured by using image guides in which single fibers of optical fibers are bundled and regularly arranged to transmit an optical image. There is.

In general, a fiberscope is provided with a light guide 2 in which optical fibers are bundled in parallel with the image guide 1 near the image guide 1 as shown in FIG. Two
Are covered by the same sheath 3.

The image guide 1 has an objective lens portion 5 having an objective lens 4 attached to the tip end thereof, and an eyepiece portion 7 having an eyepiece lens 6 attached to the base end portion thereof. The image of the observation target projected on the screen can be observed.

An illumination device 8 is connected to the end of the light guide 2 on the observer side, and illumination light is introduced from the illumination device 8 into the light guide 2 to illuminate an observation object. ing.

Further, the present inventors previously proposed a fiberscope in which illumination light passes through an image guide (Japanese Patent Application No. 60-1645).
No. 56). This is shown in FIG. 5, the same parts are designated by the same reference numerals, and the description thereof will be omitted.

In this fiberscope, a light introducing portion 9 is provided at an end portion of the image guide 1, and one end of the light guide 2 is connected to the end portion so that the end surface is perpendicular to the end surface of the image guide. The half mirror 10 is arranged so that a part of the light emitted from the end face is reflected and enters the incident surface of the image guide 1.

In each of these fiberscopes, the observation object can be observed by connecting the eyepiece 7 to various cameras or by directly visually observing from the eyepiece.

[Problems to be Solved by the Invention] However, the former fiberscope has the following drawbacks. That is, since the light guide is provided in the same sheath as the image guide, the diameter of the flexible portion at the tip and the middle of the fiberscope becomes large.

Since two types of guides, a light guide and an image guide, are required over the entire length, the internal structure becomes complicated.

Since the illumination range of the light guide and the observation range of the image guide must match, it is necessary to provide an optical component such as a lens according to the observation range at the illumination light emitting end of the light guide.

If either the light guide or the image guide breaks, it is difficult to replace only the broken one.

The latter was proposed by the present inventors to solve the former drawback, and most of the drawbacks have been solved, but the illumination light from the light guide 2 is reflected by the half mirror 10, and the image guide The light entering the incident surface of No. 1 is strongly reflected by this incident surface and enters the observer side together with the image of the observation object, so the S / N ratio of the image deteriorates and it becomes difficult to observe. was there.

In order to reduce this reflected light as much as possible, it is conceivable to apply antireflection coating such as MgF ₂ to both ends of the image guide 1 or the end surface of the objective lens 4, but with such antireflection coating The effect was unsatisfactory.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image scope which solves not only the former drawback but also the latter drawback.

[Means for Solving the Problems] In order to achieve the above object, the image scope of the present invention is provided with an image guide, an eyepiece attached to one end of the image guide, and an other end of the image guide. In the image scope having a structure in which the objective lens section and the light introducing mechanism for injecting the illumination light from the end surface of the image guide on the eyepiece side are shared, and the image guide is shared as a passage of the illumination light, A refractive index matching agent is filled between the eye-side end surface and the exit end of the light introducing mechanism and between the image guide and the objective lens section.

"Action" It is introduced from the light receiving mechanism by filling a refractive index matching agent between the end surface of the image guide on the eyepiece side and the emitting end of the light introducing mechanism and between the image guide and the objective lens section. It is possible to prevent the problem that the illumination light is reflected by the end surface of the image guide or the objective lens section.

[Embodiment] FIG. 1 shows an embodiment of an image scope according to the present invention, in which reference numeral 11 is a cross section of an image fiber, an image bundle or a rod lens in which a large number of optical fibers are regularly bundled. It is a circular image guide. The outer periphery of the image guide 11 is covered with a sheath 12 made of a flexible synthetic resin. A cylindrical objective lens unit 13 is attached to one end of the image guide 11, and an objective lens 14 is fitted in an opening of the objective lens unit 13. A window 14a is attached to the front of the objective lens 14.

This objective lens 14 has one end surface 11 of the image guide 11.
It is mounted on the same axis as the image guide 11 so as to project the image of the observation object on a, and the distance between the objective lens 14 and the end surface 11a is the focal length of the objective lens 14 and the objective lens 14 and the observation object. It is decided in consideration of the distance to things.

The other end of the image guide 11 is inserted and fixed to the objective side 15a of the T-shaped light introducing mechanism 15. On the light guide side 15b of the light introducing mechanism 15, one end of a light guide 16 that bundles a large number of optical fibers and is covered with a sheath 12 is inserted and fixed, and the other end of the light guide 16 is illuminated. Device 17 is connected. The illuminating device 17 is provided with a light emitting section and an illuminating lens (both not shown) inside thereof, and is configured so that the illuminating light generated by the illuminating section is converged by the illuminating lens and introduced into the light guide 16. ing.

Further, the eyepiece side 15c of the light introducing mechanism 15 has a small-diameter side end of a truncated cone-shaped eyepiece portion 18 fixed, and the eyepiece side 15c of the light introducing mechanism 15 and the eyepiece. Eyepieces 19 and 19 are attached to the portion 18.

An optical isolator 20 is housed inside the light introducing mechanism 15. As shown in FIG. 2, this optical isolator 20 is a known cube-shaped polarizer (usually referred to as a polarization beam splitter) in which a pair of right and left prisms 21 and 21 are bonded to each other, and a bonding surface from a surface 20a. An unpolarized light beam of a single wavelength incident on the dielectric multilayer coating layer of 21a at an angle of 45 ° emerges from the surfaces 20b and 20c as two straight lines having a branch angle of exactly 90 °. It is split into polarized light. In that case, the ray 22 emitted from the surface 20b is p−
The light ray 23 which is polarized and emerges from the surface 20c is s-polarized.

This optical isolator 20 has the axis of the image guide 11,
At a position perpendicular to the axis of the light guide 16, the bonding surface 21a is aligned with the axis of the image guide 11 and the light guide 1.
It is fixed so that it makes an exact 45 ° with each of the six axes.

Between the optical isolator 20 and the end face 11a of the image guide 11, between the end face 11b of the image guide and the objective lens 14, and between the objective lens 14 and the window 14a, a refractive index matching agent 2 is provided.
4 is filled.

The refractive index matching agent 24 is used for the image guide 11 and the objective lens.
14 and the optical isolator 20 are made of a material having a refractive index similar to that of optical glass, silica glass, calcite, or the like. When glass, quartz, or the like is used as the material of the image guide 11 or the like, an epoxy resin is given as an example of a material suitably used as the refractive index matching agent 24.
Examples thereof include synthetic resin materials such as acrylic resin and methacrylic resin, and liquid materials such as liquid paraffin, glycerin, and xylene.

The end face of the light guide 16 and the optical isolator 20
S-polarizer 25 indicated by a chain double-dashed line in FIG.
Only s-polarized light may be incident on the optical isolator 20.

Furthermore, the end face of the light guide 16 and the optical isolator
A condenser lens 26 is arranged between the 20 and as shown in FIG.
The light emitted from the light guide 16 may be condensed and made incident on the optical isolator 20.

The image scope configured as described above is an illumination device.
When the light emitting section 17 is caused to emit light, this illumination light is converged by the illumination lens and introduced into the light guide 16. This illumination light is transmitted into the light guide 16, irradiates the optical isolator 20 in the light introducing section 15, and the p-polarized light passing straight through it strikes the inner surface of the light introducing section 15 and disappears. The s-polarized light branched at right angles is the end face 11b of the image guide 11.
More introduced in Image Guide 11. In this case, since the refractive index matching agent 24 is interposed between the optical isolator 20 and the end surface 11b of the image guide 11, the light emitted from the optical isolator 20 is reflected by the end surface 11b of the image guide 11, and the eyepiece. Few can reach 18.

The s-polarized illumination light incident on the image guide 16 reaches the objective lens unit 13, is converged by the objective lens 14, passes through the window 14a, and illuminates the observation object. In this case, the refractive index matching agent 2 is provided between the end surface 11a of the image guide 11 and the objective lens 14 and between the objective lens 14 and the window 14a.
Since the illumination light emitted from the image guide 11 is reflected by the objective lens 14 and the window 14a, almost no illumination light reaches the eyepiece portion 18 because of the interposition of the image pickup device 4.

Then, the objective lens 14 transmits the light reflected by the observation object to the window.
The image of the observation target is projected onto the end surface 11a of the image guide 11 through the light beam 14a, but the reflected light is diffusely reflected, and thus is in a state of almost non-polarized light.

The image projected on the end face 11a in this way is transmitted to the light introducing section 15 by the image guide 11 and is transmitted to the optical isolator 20.
The s-polarized light travels to the light guide side 15b, and the p-polarized light travels to the eyepiece side 15c to be observed as an image of the observation object through the eyepiece lens 19.

By the way, the image guide part of the above-mentioned image scope is often used under severe conditions such as forcibly inserting into a meandering part or inserting in a bad atmosphere, while it is easily damaged or deteriorated. The eyepiece and the light guide are not usually subjected to severe conditions. Therefore, if the image guide and the light introducing section are configured to be detachable, when the image guide section is damaged or deteriorated, the image scope can be reproduced by exchanging it.

In that case, as described above, the intersection of the central axes of the image guide and the light guide should be located on the bonding surface of the optical isolator, and each central axis should be set at exactly 45 ° with respect to the bonding surface of the optical isolator. For example, since it is not necessary to consider the position of the image guide in the rotation direction with respect to the light introducing part, for example, as shown in FIG. 3, a part of the end of the sheath 12 of the image guide is made of a hard synthetic resin 31, and the packing is made.
It is possible to connect by a simple connecting method such as inserting 32 and screwing it into the objective side 15a of the light introducing section.

The image scope of this example includes the end face 11b of the image guide between the optical isolator 20 and the end face 11a of the image guide 11.
And the objective lens 14, and between the objective lens 14 and the window 14a, a refractive index matching agent having a refractive index similar to the constituent materials of the image guide 11, the objective lens 14 and the optical isolator 20.
Since 24 is provided, the light guide 16 to the optical isolator 20
The illumination light entering the inside of the image guide 11 through the image guide 11 is not reflected by the end portion 11b of the image guide 11 or the objective edge 14 and the reflected light reaches the eyepiece portion 18 and the image of the observation object is obtained. It is possible to prevent the inconvenience of lowering the S / N ratio of. A clear image of the observation object can be obtained.

In the previous example, the light guide 16 to the optical isolator
The illumination light was made incident on the image guide 11 through 20,
A half mirror or the like may be used instead of the optical isolator 20.

(Example) The antireflection effect of the refractive index bonding agent was investigated.

First, an epoxy resin having a refractive index of 1.51 was used as a refractive index matching agent, and the reflectance between a typical optical material used for an image scope and this epoxy resin was measured. The results are shown in Table 1.

On the other hand, the reflectance between the optical glass (Bk ₇ ) and the air,
That is, as a result of measuring the reflectance without using the refractive index matching agent, the reflectance was about 4%.

In addition, a single layer antireflection coating of MgF ₂ was applied to the surface of this optical glass, and the reflectance was measured.
%Met.

From these facts, it was found that the reflection between the optical members is extremely reduced by interposing the refractive index matching agent between the optical members such as the image guide and the lens.

[Advantages of the Invention] As described above, in the image scope according to the present invention, the image guide portion to be inserted and used can be formed thin.

Since the illumination is performed through the objective lens, the illumination range and the observation range completely match, extremely efficient illumination is performed, there is no need to provide a dedicated optical component in the light guide, and the structure is simple and economical.

The image guide part is detachable, and only the image guide part that is easily damaged or deteriorated can be replaced, and the parts are effectively used.

Since the refractive index matching agent was filled between the end surface of the image guide on the eyepiece side and the exit end of the light introducing mechanism, and between the image guide and the objective lens section, the illumination light from the light guide is reflected by the end surface of the image guide. Since it does not reach the eyepiece by being reflected by the objective lens or the objective lens, the S / N ratio of the image observed or photographed by the eyepiece is large and a clear image of the observation object can be obtained.

It is an excellent product that has many advantages and greatly contributes to medicine and industry.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of an image scope according to the present invention, FIG. 2 is a perspective view of an optical isolator, and FIG. 3 is a vertical sectional view showing an example of a method of connecting an image guide portion and a light introducing portion. FIG. 4, FIG. 5 and FIG. 5 are vertical sectional views showing a conventional fiberscope. FIG. 4 shows a type in which a light guide is arranged in parallel with an image guide, and FIG. 5 uses illumination light as an image guide. It is a figure of the type which transmits by transmitting. 11 …… Image guide 11a, 11b …… End face 13 …… Objective lens section 15 …… Light introducing section (light introducing mechanism) 18 …… Ocular section 24 …… Refractive index matching agent

Claims (1)

[Claims] 1. An image guide, an eyepiece unit attached to one end of the image guide, an objective lens unit attached to the other end of the image guide, and illumination light incident from an end face of the image guide on the eyepiece side. And a light introduction mechanism that
In an image scope having a structure in which the image guide is shared as a passage for illumination light, a refractive index matching is performed between the eyepiece side end face of the image guide and the emitting end of the light introducing mechanism and between the image guide and the objective lens portion. An image scope characterized by being filled with an agent.