JPH04265705A - Production of infrared lens - Google Patents

Abstract

PURPOSE:To prevent the corrosion or surface deterioration of a manufacturing jig at the time of the molding processing of an infrared lens under pressure using metal halide as a lens material and to facilitate the mirror polishing of said jig in the manufacturing of the infrared lens. CONSTITUTION:The punch rod 1, container 2 and receiving rod 3 directly coming into contact with a lens material composed of metal halide 4 are prepared from a nickel alloy material and this manufacturing jig is used to mold metal halide 4 being the lens material under heating and pressure.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an infrared lens for use in equipment that utilizes infrared light.

0002

[Prior Art] Currently, devices that use infrared light, such as laser-applied equipment or thermal imaging sensors, and their parts (
Infrared lenses used in infrared devices (hereinafter referred to as infrared devices) are
Zinc selenide (ZnSe)/Gallium arsenide (GaAs)
- Molded from an infrared transmitting material such as germanium (Ge) using an optical polishing method. In this method, a mirror surface is formed from a crystal produced by a CVD method or the like through several steps from rough polishing to final polishing using abrasive grains.

On the other hand, as a method for producing an infrared lens at a lower cost, there is a method in which an infrared optical member made of a metal halide is pressure-molded at a temperature below its melting point (Japanese Patent Application Laid-Open No. 59-1971).
(Refer to Publication No.-212801). As the metal halide, a solid solution of silver chloride and silver bromide and a solid solution of thallium bromide and thallium iodide (KRS-5) are mainly used, and as the manufacturing jig, ceramics, super steel materials, etc. are used. In this manufacturing method, the surface of the manufacturing jig that comes into contact with the metal halide is processed into a lens shape, and then mirror-polished.
The lens material is pressure molded at a predetermined temperature.

0004

However, in the conventional manufacturing method described above, when a ceramic material is used as a manufacturing jig, the ceramic material is chemically very stable but has poor workability. In other words, mirror polishing of ceramic is extremely difficult. There is a method of processing ceramic into a lens shape and mirror-polishing it by performing electrical discharge machining using conductive ceramic, but even with this method, mirror-finishing cannot be achieved with high precision. On the other hand, metal materials have good workability and can be mirror polished easily. However, since a large pressure of 8 tons/cm2 or more is applied during pressure molding, a high-strength material must be used for use as a manufacturing jig. Super steel materials are being considered as high-strength metal materials. If super steel is used, 20 tons/cm
There is no problem even if a pressure of about 2 degrees is applied. However, super steel is highly reactive with metal halides, especially silver chloride and silver bromide, and corrodes after a single forming. Furthermore, the peelability during molding was poor, and the surface of the lens was sometimes scratched.

The present invention solves the above-mentioned problems, and provides a manufacturing method for manufacturing an infrared lens by easily mirror-polishing the manufacturing jig and without corrosion of the jig or deterioration of the lens surface during pressure molding of the lens. The purpose is to provide.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an infrared lens manufacturing method in which an infrared optical member made of a metal halide is pressure-molded at a temperature below its melting point. A nickel alloy is used as the material for the part that comes into contact with the metal halide.

[0007]

[Operation] As mentioned above, ceramic materials are chemically very stable, but have poor workability. Super steel materials have good workability and can be easily polished to a mirror finish, but they are chemically reactive and corrode quickly. In contrast to these materials, nickel alloy can withstand pressures of about 15 ton/cm 2 in terms of strength, has good workability, and has no reactivity with metal halides. Therefore, if this is used, the manufacturing jig can be easily polished to a mirror surface, and an infrared lens can be manufactured without corrosion of the jig or deterioration of the lens surface during pressure molding.

[0008]

EXAMPLE Hereinafter, an example of the method for manufacturing an infrared lens according to the present invention using a solid solution of silver chloride and silver bromide as the metal halide will be described with reference to FIG. FIG. 1 is a sectional view of an apparatus for carrying out the manufacturing method. In the figure 1
1 is a punch rod whose pressing surface is mirror-polished into a lens shape, 2 is a container, 3 is a receiving rod with a mirror-polished lens shape, 4 is a silver chloride/silver bromide crystal, 5 is a heat insulating plate, and 6 is a heating heater. It is. Among these, punch rod 1, container 2, receiving rod 3
is manufactured from nickel alloy.

[0009] Molding is carried out as follows. A silver chloride/silver bromide crystal 4 cut to an appropriate size is placed in a container 2 equipped with a receiving rod 3 whose upper surface is mirror-polished into a lens shape, and after being heated to an appropriate temperature with a heater 6, The punch rod 1 whose lower pressurizing surface is mirror-polished into a lens shape,
Maintain the pressurized state for a certain period of time. By the above method, a polycrystalline infrared lens having a grain size of about 1 to several μm is molded.

[0010] As a result of molding a lens using a nickel alloy jig using silver chloride/silver bromide crystals under the manufacturing conditions shown in Table 1, there was no deterioration of the lens surface and no damage to the jig. was able to manufacture it. Furthermore, no corrosion of the jig was observed even after molding 100 silver chloride/silver bromide lenses.

[0011]

[Table 1]

0012

Effects of the Invention As is clear from the above embodiments, according to the present invention, in the method of manufacturing an infrared lens in which an infrared optical member made of a metal halide is pressure-molded at a temperature below its melting point, the manufacturing jig is As the material for the parts that come into contact with metal halides, we use a nickel alloy that has good workability and high strength, and at the same time has no reactivity with metal halides, making it easy to mirror-polish the manufacturing jig and pressurize. Infrared lenses can be manufactured without corrosion of jigs or deterioration of the lens surface during molding.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an apparatus for carrying out the infrared lens manufacturing method according to the present invention.

[Explanation of symbols]

1 Punch rod with mirror polished pressure surface (manufacturing jig that comes into contact with metal halide) 2 Container (manufacturing jig that comes into contact with metal halide) 3 Receiving rod with mirror polish (manufacturing jig that comes into contact with metal halide) ingredients)

Claims (2)

[Claims] Claim 1: A method for manufacturing an infrared lens in which an infrared optical member made of a metal halide is pressure-molded at a temperature below its melting point, in which a nickel alloy is used as a material for a manufacturing jig that comes into contact with the metal halide. Characteristic infrared lens manufacturing method. 2. The method for manufacturing an infrared lens according to claim 1, wherein a solid solution of silver chloride and silver bromide or a solid solution of thallium bromide and thallium iodide is used as the metal halide.