JPH0210302A - Single crystal infrared fiber manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a single crystal infrared fiber, a high energy transmission fiber useful for laser scalpels or laser processing machines.

BACKGROUND OF THE INVENTION Recently, attempts have been made to utilize laser light in the infrared region in laser scalpels in the medical field, processing machines in the industrial field, etc., and CO2 lasers (oscillation wavelength: 10.degree. 6 .mu.m) are often used. If a fiber capable of transmitting these wavelengths in the mid-infrared region with high energy can be obtained, a wide range of applications will become possible.

As a mid-infrared fiber, a solid solution of thallium bromide or thallium iodide (KRS-5) is used.

These fibers are hot extruded at 200 to 300'C and are made of polycrystals with an average grain size of several tens of micrometers.

Problems to be Solved by the Invention However, metal halide infrared fibers manufactured by conventional methods are polycrystalline as described above. When such a fiber transmits laser light,
There is a lot of scattering at grain boundaries, so high energy transmission cannot be expected. Conventional fiber has a diameter of 0.5 mm and a length of 1.5 mm.
m, the maximum transmission power is only about 200 to 250W.

An object of the present invention is to reduce internal scattering and enable high-energy transmission when laser light is transmitted through a mid-infrared fiber.

Means for Solving the Problems The present invention provides thallium halides, cesium halides,
The above object is achieved by heat-treating a polycrystalline fiber produced by extruding a compound consisting of at least one type of silver halide to cause grain growth and single crystallization.

Operation In the present invention, since grain growth reduces scattering at grain boundaries, the entire fiber is made into a single crystal by heat treatment, allowing considerably higher energy transmission compared to conventional polycrystalline fibers.

Example Embodiments of the present invention will be described below with reference to the drawings.

Figure 3 shows a KRS-5 polycrystalline fiber (diameter 0
, 5 mm), and the relationship between the maximum incident power for a short length of 10 cm. As is clear from the figure, the maximum incident power increases as the particle size increases. This is because grain growth reduces scattering at grain boundaries. Therefore, if the entire fiber is made into a single crystal by heat treatment, it becomes possible to transmit significantly higher energy than conventional polycrystalline fibers.

FIG. 1 is a schematic diagram of a single crystallization apparatus using a zone furnace for polycrystalline fiber, in which 1 is a furnace core tube, 2 is a heater, and 3 is an infrared fiber.

Single crystallization is performed as follows. A polycrystalline infrared fiber 3 manufactured by hot extrusion method is installed inside the furnace core tube l.Next, the heater 2 is heated 4s+w/h from the end face of the infrared fiber 3.
While moving at a certain speed, the infrared fiber 3 is heat treated at an appropriate temperature to grow grains in the long axis direction of the fiber and form a single crystal.

FIG. 2 is a graph showing the relationship between the heat treatment time, heat treatment temperature, and end face grain size when a KRS-5 polycrystalline fiber is heat treated in an electric furnace. Even after heat treatment at 200°C for 30 hours, the end face grain size is about 350/A m, but 250'
When heat treated with C, the end face grain size becomes 500 μm, which is the same as the diameter of the fiber, at about 1 o'clock. Moreover, the melting point of KRS-5 is 415°C.

Therefore, the appropriate heat treatment temperature is 250°C to 300°C.

Effects of the Invention As is clear from the above explanation, the present invention eliminates scattering at grain boundaries by heat-treating a polycrystalline infrared fiber to grow grains and turn it into a single crystal, thereby eliminating the scattering caused by conventional manufacturing methods. It enables higher energy transmission than polycrystalline infrared fibers, which has the effect of achieving high output in laser scalpels, laser processing machines, etc.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a polycrystalline fiber single crystallization apparatus using a zone furnace in a method for manufacturing single-crystal infrared fiber according to an embodiment of the present invention, and FIG. Figure 3 is a graph showing the relationship between heat treatment time, heat treatment temperature, and end face grain size when heat treated with heat treatment.
FIG. 10 is a graph showing the relationship between the end face grain size and the maximum incident power for a short piece having a length of locm in FIG. 1... Furnace core tube, 2... Heater 3... Name of infrared fiber agent Patent attorney Toshio Nakao Annealing time (h)

Claims (3)

[Claims] (1) Heat-treating a polycrystalline fiber produced by extruding a compound consisting of at least one of thallium halide, cesium halide, and silver halide,
A single-crystal infrared fiber manufacturing method characterized by grain growth and single crystallization. (2) The method for manufacturing a single-crystal infrared fiber according to claim 1, characterized in that a solid solution of thallium bromide and thallium iodide is used. (3) The method for manufacturing a single-crystal infrared fiber according to claim 2, characterized in that the heat treatment is performed at a heating temperature of 250°C or more and 300°C or less.