JPS609765Y2 - Optical components of interferometer type gas detector - Google Patents

Description

[Detailed Description of the Invention] This invention relates to the structure of an optical component in which a parallel plane mirror and a main prism, which are the main optical components of an interferometer type gas detector, are attached to a support base.

FIG. 1 is an optical system diagram of an interferometer type gas detector.

The light emitted from the light source 1 is converted into a suitable luminous flux by the converging lens 2,
The reflected light and refracted light are separated by the parallel plane mirror 3, each passes through the gas chamber 4, is reflected by the main prism 5, passes through the gas chamber again, and matches on the parallel plane mirror, and interference fringes are obtained by the given optical path difference. .

After that, when different gases enter the inner chamber of the gas chamber, the interference fringes move due to the difference in their refractive indexes, and the amount of movement is converted into an electrical signal by the photoconductive element 6 to obtain the gas concentration. .

The parallel plane mirror and the main prism are the optical components of the interferometer type gas detector that perform optical interference.
Displacement, strain, etc. due to temperature changes immediately cause the interference fringes to move, so the mounting method is an important issue from the viewpoint of the accuracy of the gas detector.

An example of a conventional mounting method will be explained with reference to an exploded perspective view of FIG.

The support base 7 is held on the support base by claws 8 made of thin metal pieces on the front and side edges, and the rear part is held on the support base by a stopper 9 having an eccentric ring. They were overlapped and fixed to the support stand 7 by two pillars 14 using set screws 13, and the support stand was fixed to the interferometer body with screws through the mounting holes 15.

The same method was used for the main prism.

However, with this method, in order to prevent temperature errors in the interferometer type detector, the steps are taken to adjust the strength of these fasteners one by one, conduct a temperature test each time, and repeat the above steps based on the results. There is no other choice but to rely on the intuition of experts.

In response to this, attempts have been made to consider the shape and material of the support base, as well as adhesive methods, but none of them have been able to solve this problem.

As a result of many years of study, the inventor of this invention found that the cause of the temperature error was that the parallel plane mirror and main prism were
It was found that the plane directly after that is the largest.

This idea is based on the concept of an optical component that can prevent temperature errors in interferometer type gas detectors without relying on skilled technology.

This idea will be explained using a diagram.

Figure 3A is an exploded perspective view of this embodiment, with a length of 34mm and a width of 8T! At the center of the bottom surface of the parallel plane mirror 3 having a bottom surface of
Then, a fitting 16 having a brim with a diameter of about 7 mm in the middle and a threaded end is glued together with strong adhesive, and the fitting 16 is inserted into the mounting hole 1 of the support base 7.
7 and tighten with nut 18 to install.

As for the main prism, as shown in the opening of Figure 3,
Glue a similar fixture 16 to the center of the bottom of the prism 5,
Once assembled, attach it to a support stand.

Also, depending on the arrangement of parts, it may be of a hanging type using a suitable support.

This design eliminates the contact surface between the parallel plane mirror and the main prism and the support base, which are the main causes of temperature errors, and since the fixture only glues a small area, even if there is distortion, it does not affect the optical path. This method not only significantly reduces temperature errors compared to conventional methods, but also helps streamline manufacturing by reducing the number of parts, simplifying the assembly process, and omitting the temperature error adjustment process. I can do it.

Furthermore, it has been confirmed that by using the optical component of this invention, it is not only able to withstand shocks in practical use, but also has greater impact resistance than conventional mounting methods.

[Brief explanation of the drawing]

FIG. 1 is an optical system diagram of an interferometer type gas detector, FIG. 2 is an exploded perspective view of a conventional parallel plane mirror mounting method, and FIG. 3 is an exploded perspective view of this invention.

Claims (1)

[Scope of utility model registration request] Among the optical components of the interferometer type gas detector, in order to attach the parallel plane mirror 3 and main prism 5 that form the interference part to the support base, a A fixture 16 having a cross-sectional area of 20% or less of the area of the lower surface is glued, and the distance between the adhesive surface of the fixture and the surface of the support base 7 is 1rIr! An optical component characterized in that it is approximately n.