JPH03282400A - Window material for optical purpose - Google Patents

Abstract

PURPOSE:To contrive the increase in the area of a window material, the reduc tion of a cost and the improvement in durable strength by reinforcing filmlike diamond with grid or net like carbon fibers from both front and rear surfaces. CONSTITUTION:The filmlike diamond of about 2mum thickness is deposited by a microwave plasma CVD method on one surface of an Si substrate material 1 and a mesh 3a of about 7mum carbon fibers is mounted thereon; further, a metallic window frame 4a is fixed by metallic solder 5a, etc., thereon to fix the mesh 3a to one surface of the diamond 2. The base plate material 1 is removed by etching. This material is then turned over and the mesh 3b is fixed to the rear side by the similar method. The optical window material formed by reinforcing the front and rear of the diamond 2 with the meshes 3a, 3b in such a manner can be formed to the larger area and the reduction of its cost is possible as well. In addition, the generation of warpage and waving is prevented and the durable strength is improved to prevent the failure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a window material used in optical systems for ultraviolet rays, visible rays, infrared rays, or X-rays.

[Summary of the Invention] The optical window material of the present invention has a window portion made of a film-like diamond reinforced from both the front and back sides with lattice-like or net-like carbon fibers.

By reinforcing the front and back surfaces of a thin, brittle film-shaped diamond using extremely thin carbon fibers that have good X-ray transparency and high tensile strength, we can improve the inherent transparency of film-shaped diamonds to light and X-rays. It is possible to increase the area of the window material, reduce the cost, and improve the pressure resistance without damaging the window material.

[Prior Art] As is well known, diamond has excellent light transmittance in a wide range from the ultraviolet region with a wavelength of approximately 0.3 μm to the far infrared region with a wavelength of approximately 25 μm, and is composed of carbon atoms with a small atomic number. Therefore, the X-ray transparency is also extremely good. Furthermore, it has high heat resistance of about 1200°C in vacuum and about 600°C in air, so it is expected to be widely used as an optical window material.

With conventional technology, when trying to manufacture an optical window material made of diamond, methods such as using natural or artificially synthesized diamond crystals with a diameter of several millimeters as raw materials and finishing them thinly through mechanical processing such as polishing and grinding can be considered. .

[Problem to be solved by the invention] However, in this case, large diamond crystals are rare and extremely expensive, so it is extremely difficult to manufacture a window material with a large area (for example, 1 cm or more in diameter). Furthermore, because diamond has the highest hardness of all materials, the cost of machining is extremely high.

The object of the present invention is to solve these problems and provide a method for manufacturing an optical window material made of diamond with good light transmittance, which is inexpensive and can be made into a large area.

[Means to solve the problem]

In order to solve the above problems, in the present invention, a film-like diamond synthesized by a vapor phase method is used as a window material in an optical window material, and the window part is reinforced with the film-like diamond from both the front and back sides. It has a three-layer structure made of lattice-like or net-like carbon fibers.

[Function] As shown in FIGS. 1 and 2, the optical window material according to the present invention has a film-like diamond reinforced with a carbon fiber lattice or mesh having high bowing strength. Prevents diamond warping and waviness, and
The compressive strength can be significantly improved and breakage can be prevented (Note: For example, commercially available carbon fibers have a tensile strength of 300 to 500 kg/mm'' at a diameter of around 7 μm).

In particular, it is made of a structure in which film-like diamond, which is originally thin and brittle, is reinforced by sandwiching carbon fiber lattice or netting from both the front and back sides, so it can withstand pressure from either the front or back side. A noteworthy feature of the present invention is that it has particularly high strength.

Furthermore, since extremely thin carbon fibers with a diameter of several μm are used, the amount of light or X-rays transmitted through the window portion blocked by the carbon fiber lattice or net is extremely small and can be ignored. Furthermore, since carbon fibers are composed of C atoms that have good X-ray transparency, they are particularly advantageous for transmitting X-rays.

In addition, the method of forming a film-like diamond is thermal CVD method, Blaz? There are CVD methods, photo-CVD methods, ionized vapor deposition methods, ion beam methods, plasma jet methods, etc., and there is no problem with the present invention using any of them, and the area where the film can be formed is larger than that of conventional diamond crystals by machining. Compared to the method of processing into materials, a significantly larger area can be achieved and manufacturing costs can be significantly reduced.

[Example] Hereinafter, an example of the present invention will be described based on the drawings. Third
Figures (A) to (D) are explanatory diagrams of an example of the manufacturing process of the optical window material of the present invention.
It is called a figure.

First, as shown in figure (A), the diameter is 30 mm and the thickness is 200 L.
A 81 substrate material l of Lm was prepared, and a 2 μm thick film diamond ■ was deposited on one side of the substrate using the microwave plasma CVD method (Japanese Unexamined Patent Publication No. 58-110494) under the synthesis conditions shown in Table 1. .

Table 1 Next, as shown in Figure (B), a carbon fiber mesh 3a with a diameter of 7 μm is placed on the film diamond
, and then a metal window frame 4a (outer diameter 30 mm)
, an inner diameter of 20 mm, and a thickness of 2 mm) with metal solder 5a or the like, thereby fixing a carbon fiber mesh 3a to one side of the film-like diamond 2.

Next, as shown in Figure 0, a masking agent 6 is applied to the entire surface of the Si substrate material 1 except for the part, and then, as shown in Figure D, it is immersed in a mixed acid solution of HF and HNO. 8
1 The substrate material 1 was removed by etching, and then the masking agent was also removed and cleaned.

Furthermore, after turning this upside down and placing a new carbon fiber mesh 3b on the side of the film diamond 2 that has not yet been reinforced with the carbon fiber mesh, as shown in FIG. 2, a metal window is placed on top of it. The frame 4b was fixed with metal solder 5b or the like. As a result, an optical window material having a structure in which the front and back screens of film-like diamond were reinforced with carbon fiber mesh as shown in FIG. 1 was obtained.

FIG. 4 is an explanatory diagram of an apparatus used to test the compressive strength of the window material obtained according to the present invention. A window material 9 according to the present invention is attached as a partition at the connecting portion between the vacuum chamber 7 and another vacuum chamber 8. In addition, each chamber is connected to a gas cylinder 1 via a stop valve 10.11.
2, and also connected to the vacuum pump 15 via stop valves 13 and 14, and further connected to the atmospheric environment via leak valves 16 and 17.

Using this test device, the inside of the vacuum chamber 7.8 was alternately pressurized and depressurized, and this window material
As a result of tests to see if it had sufficient strength against pressure from any direction on the back side, the film diamond did not break or leak at all under a pressure difference of 2 atmospheres, and this window material proved to be strong enough to withstand pressure from any direction. It was confirmed that it has high strength against pressure from both the front and back sides.

[Effects of the Invention] As described above, according to the present invention, it is possible to increase the area of an optical window material made of diamond, and it is possible to reduce both raw material costs and manufacturing costs.

Furthermore, since the carbon fibers reinforce the film-like diamond in the window, it is possible to prevent warping and waviness, significantly improve pressure resistance, and prevent breakage.

Furthermore, it has a wide range of light transmittance and also has good low energy X-ray transmittance.

[Brief explanation of the drawing]

1 and 2 are a perspective view and a sectional view showing an example of an optical window material made of film-like diamond according to the present invention. Moreover, FIGS. 3(A) to 3(D) are explanatory diagrams of an example of the manufacturing process of the optical window material of the present invention. Moreover, FIG. 4 is an explanatory diagram of a pressure-resistant strength testing apparatus for window materials. l ・ ・ ・ 2 ・ ・ 3 a, 4a. 5 a, 6 ・7. 9 ・10. 12 ・13. 15 ・ 16, b b b 8 ・ ・ l 1 ・ 14 ・ 17 ・ ・Substrate material, film diamond, carbon fiber mesh, window frame, metal solder, masking agent, vacuum chamber, window material, stop valve, gas cylinder, Stop valve/vacuum pump/leak valve 1 Figure 2 Figure rA) (Snake) Above '83 Figure

Claims (1)

[Claims] In an optical window material made of film-like diamond synthesized by a vapor phase method, the window part has a three-layer structure of film-like diamond and lattice-like or net-like carbon fibers reinforcing it from both the front and back sides. An optical window material characterized by: