JPH0660974B2 - Cryogenic fiber scope - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cryogenic fiber scope used for observing various developments at cryogenic temperatures.

(Prior Art) There has been a demand for directly observing various phenomena under extremely low temperatures, but a fiber scope suitable for enabling such observation has not been put into practical use.
The reason is that when a fiber scope currently used at room temperature is used at extremely low temperatures, various inconveniences occur and it is difficult to solve them.

The main ones of these disadvantages are as follows.

(1) When a fiber scope used at room temperature is used at an extremely low temperature represented by liquid helium (hereinafter abbreviated as LHe) temperature, stress and embrittlement due to thermal contraction occur inside the fiber scope body. The image guide, objective lens, etc. contained in it are damaged and cannot be used.

(2) Since it is difficult to completely evacuate the inside of the fiber scope, moisture contained in the atmosphere inside the fiber scope condenses and adheres to the objective lens, deteriorating the observation performance.

(Problems to be Solved by the Invention As described above, conventionally, the fiber
Attempts have been made to use the scope at extremely low temperatures, but the image guide, objective lens, etc. were damaged due to stress and embrittlement due to heat shrinkage, and the moisture contained in the atmosphere inside the fiber scope was reduced. There was a problem that the particles were condensed and adhered to the objective lens to deteriorate the observation performance, and a fiber scope usable at extremely low temperatures was not realized.

The present invention has been made in view of the above circumstances,
It is an object of the invention to provide a fiber scope for cryogenic use, which does not damage the fiber scope even when used at cryogenic temperature and does not deteriorate observation performance.

(Means for Solving the Problem) A cryogenic fiber scope according to the present invention includes a fiber scope body having an objective lens at the tip, and a multi-sheath containing the fiber scope body therein.
It is characterized by comprising a heat insulating layer provided between the sheaths of the multi-sheath, and a desiccant for absorbing water present in the internal atmosphere of the multi-sheath.

(Operation) The cryogenic fiber scope configured as described above is used at cryogenic temperature because the fiber scope body is housed in a multi-sheath and a heat insulating layer is provided between these sheaths. Also, the fiber scope in the multi-sheath will be kept warm within its operating temperature limit range,
The fiberscope is not damaged.

In addition, it is difficult to completely evacuate the inside of the fiber scope, and even a small amount of water exists in the atmosphere inside the fiber scope. In the present invention, since the desiccant for absorbing the water existing in the atmosphere inside the multiple sheath is provided, the water contained in the atmosphere inside the multiple sheath can be completely removed by this desiccant.

Therefore, even when used at extremely low temperatures, there is no concern that water will condense in the multiple sheaths, and adhesion to the objective lens can be prevented.

(Example) An example of a cryogenic fiber scope of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an embodiment of the cryogenic fiber scope of the present invention.

In FIG. 1, inside the fiber scope body 1, a light guide 3 for guiding light from a light source (not shown) through a plug 6 and an image guide 2 for guiding an observation image through an objective lens 4. , And the objective lens 4 is attached to one end of the fiber scope body 1 and the eyepiece 5 is attached to the other end.

The fiber scope body 1 is housed in, for example, a double sheath (hereinafter, referred to as a multi-sheath) composed of an inner sheath 7 and an outer sheath 8, and a space between the inner sheath 7 and the outer sheath 8 is provided. A super-insulating layer 9 is provided in the to protect the fiber scope from cryogenic temperatures. The fiber scope body 1 and inner sheath 7
A spacer (not shown) made of a heat insulating material is inserted between the inner sheath 7 and the outer sheath 8 to prevent direct contact with each other, thereby ensuring the function of the super heat insulating layer 9. There is.

As described in the conventional problems, it is difficult to completely evacuate the inside of the fiber scope body 1 in manufacturing, so that the influence of water contained in the atmosphere inside the fiber scope body 1 is removed. Further, a desiccant (not shown) is loaded in the vicinity of the objective lens inside the multi-sheath.

In this way, by absorbing the water inside the multi-sheath with the desiccant, even when the fiber scope is used at an extremely low temperature, no condensation of water occurs. That is,
When the fiber scope is protected from cryogenic temperature by the multi-sheath and the super insulation layer as in the present invention, it is possible to protect the fiber scope body 1 within the use limit temperature of the fiber scope itself. It is impossible to prevent a slight decrease in temperature. If water is contained in the multi-sheath atmosphere, this temperature decrease causes water condensation, but since the water itself can be absorbed by the desiccant to the extent that water condensation does not pose a problem, the above-mentioned water condensation occurs. Therefore, it is possible to completely avoid the inconvenient situation that the moisture of the objective lens 4 adheres to deteriorate the observation performance.

According to the fiber scope configured as described above, the fiber scope is not damaged even when used at extremely low temperatures, and condensed water does not adhere to the objective lens, which has been difficult in the past. A fiber scope that is especially suitable for observation at extremely low temperatures can be realized.

It should be noted that thin plates 10 and 1 of sapphire (or a transparent member such as quartz) are provided in front of the multi-sheath objective lens 4.
It is convenient to keep the super-insulating layer 9 airtight by disposing 1 and joining it with the inner and outer sheaths 7, 8 respectively using Kovar. Further, the bellows 12 are arranged at the cryostat inlet portions of the inner and outer sheaths 7 and 8 to maintain the airtightness of the super insulating layer 9 and to allow the coarse adjustment of the observation position of the fiber scope body 1. , The usability is extremely improved.

In addition, part of the inner and outer sheaths 7 and 8 is attached to the bellows 1.
With the configuration of 3 and 14, the flexibility under extremely low temperature can be more reliably ensured. It should be noted that the bellows 13 and 14 are provided for the case where the temperature of the fiber scope body 1 is slightly lowered and the flexibility is impaired even though the bellows 13 and 14 are protected by the multiple sheaths and the super insulation layer 9. It is also possible to dispose a heater 15 for heating as shown in the drawing at a position corresponding to, and heat it at the time of use.

Further, when the fiber scope of the present invention is used for observation in LHe, there is a problem peculiar to LHe in that bubbles are generated from the inside of LHe due to heat of illumination light and the observation is obstructed by the bubbles. In such a case, if the heat ray filter 16 is mounted in front of the light guide 3 in this case, the generation of bubbles is suppressed, which is effective.

Also, when the object to be observed is a metal surface or the like, if the illumination light is directly irradiated, the surface will shine, which may be difficult to observe.
In such a case, a frosted glass filter may be provided (when the heat ray filter is also used, the surface of the heat ray filter may be formed into frosted glass) to suppress the influence of reflected light for convenient observation. good.

The present invention is not limited to the above description and can be variously modified and used without departing from the scope of the invention.
That is, in the above description, the fiber scope is a direct-view type, but a side-view type or a perspective type may be used instead, and the image guide and the light guide are integrated. Alternatively, a separate type may be used.

(Effect of the invention) As described in detail above, according to the present invention, the fiber scope is not damaged even in use under cryogenic temperature.
In addition, a cryogenic fiber scope that does not allow condensed water to adhere to the objective lens can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of an embodiment of a cryogenic Faber scope of the present invention. 1 ...... Fiber scope body 2 ...... Image guide 3 ...... Light guide 4 ...... Objective lens 7 ...... Inner sheath 8 ...... Outer sheath 9 ...... Super insulation layer 12, 13, 14 ...... Bellows 15 ... … Heating heater 16 …… Heat ray filter

Claims (2)

[Claims] 1. A fiber scope body having an objective lens at a tip thereof, a multi-sheath for accommodating the fiber scope body therein, a heat insulating layer provided between the sheaths of the multi-sheath, and an inside of the multi-sheath. A cryogenic fiber scope, which is composed of a desiccant for absorbing water present in the atmosphere. 2. The cryogenic fiber scope according to claim 1, wherein at least a part of the multi-sheath is made of bellows.