JPS6240405A - Incident end structure of light guide for power transmission - Google Patents

Abstract

PURPOSE:To prevent the heat deterioration of the light guide without heating the light guide and providing a thermal insulation parts having a quartz rod and a passage of a cooling medium formed at an end surface side of said rod on the incident end surface of the light guide. CONSTITUTION:An infra-rod insulating deposited film 2 is provided on the end surface of a going out side of the quartz rod 1. The deposited film 2 is a filter of cutting the infra-red ray having >=1mum a wavelength, and is composed of the deposited film of an alternative laminated films made of for example MgF2 and ZnS. The thermal insulation parts 3 is pro vided on the quartz rod 1 so as not to transfer an exothermic heat of the quartz rod due to an absorption of the infra-red to the light guide. The thermal insulating parts 3 is composed of a metal having a good heat conductive property such as copper and a copper alloy. The quartz rod 1 is fixed by coupling closely an outer circumference of the quartz rod 1 with an inner circumference of the thermal insulating parts 3 at an open side of said parts 3. The heat of the quartz rod 1 is transferred to the cooling medium through the insulating parts 3, and discharged to the outside of the quartz rod, thereby preventing the thermal transmission for the incident part of the handle 4 by flowing the cooling medium such as a cooling water or gas from the inlet 3b of the cooling medium to the cooling passage 5.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the structure of the incident end of a light guide for power transmission, and is designed to prevent heat deterioration of the light guide due to high-output incident light. It is.

[Prior art and its problems]

Original fiber bundles made by bundling several original fibers together and large-diameter fibers are used as light guides for power transmission in welding equipment such as brazing and soldering, which use high-output light beams, and laser cutting equipment. .

By the way, the entrance end surface of such a power transmission light guide becomes hot because high-output light is incident thereon, and furthermore, the light guide itself absorbs infrared light of wavelength/prR or more of the incident light. Even 1%! temperature, which may cause thermal deterioration of the focusing agent of the fiber bundle or thermal damage to the polymer thread covering material of the large diameter fiber.

To solve this problem, the conventional method has been to cool the vicinity of the entrance end with water or air. However, incident! With such a cooling method in the @ section, it is difficult to effectively prevent heat generation due to absorption of infrared light by the light guide itself.

[Means for solving problems]

Therefore, in the present invention, a heat shielding member having a quartz rod and a coolant passage formed on one end surface of the rod is disposed on the light guide entrance end surface to reduce the infrared light of the incident light. The structure is such that the quartz rod absorbs the heat generated by the quartz rod, and by flowing cooling water or the like into the coolant passage, pressure is not transmitted to the light guide.

The drawing shows an example of the structure of the light guide entrance end of the present invention, and the reference numeral l in the drawing represents a quartz rod. The quartz rod 1 is a columnar body made of general quartz glass, and serves as a filter that almost completely absorbs infrared light with a wavelength of 3 μm or more among incident light and prevents infrared light from entering the light guide body. Due to its infrared light absorption properties, its length and thickness are 20t11. It is considered sufficient.

σ) An infrared light blocking vapor deposited film 2 is provided on the end face of the quartz rod 1 on the emission side. This vapor deposited film 2 is.

Further, it is a filter that blocks infrared light having a wavelength of 1μ or more, and is made of, for example, MgF, Zn8, etc. deposited as an alternating multilayer film. This vapor-deposited film 2 does not need a cover when the power of the incident light is low or when the infrared light component of 7 to 3 μm is small.

The quartz rod 1 is provided with a heat shielding member 3 for preventing heat generated by absorption of infrared light by the quartz rod 1 from being transmitted to the light guide. The heat shielding member 3 is made of a metal such as copper or copper alloy having good thermal conductivity, and has an approximately cylindrical shape with a bottom, and a quartz rod l is placed on the opening side to shield the outer peripheral surface. It is fixed in close contact with the inner peripheral surface of the member 3. Further, at the bottom of the heat shielding member 3, a through hole 3a for passing the light guide, a coolant introduction hole 3b, and a coolant discharge hole 3c are formed, respectively.

The through hole 3a has 7 eyes as a light guide.
The quartz rod 4 is fixed in a liquid-tight manner and is spaced apart from the quartz rod 1 so that a constant gap 5 is formed between the incident end face and the vapor deposited film 2.

The void 5 thus formed becomes a refrigerant passage communicating with the refrigerant introduction hole 3b and the refrigerant discharge hole 3c.

In such a structure with an input end of m, the light is input from the quartz rod l side, but the quartz rod l
Since the infrared light component is absorbed by the vapor deposited film 2, the quartz rod 1 generates heat. At this time, the refrigerant introduction hole 3 is inserted into the refrigerant passage 5.
When a refrigerant such as cooling water or cooling gas flows through b, the heat of the quartz rod 1 is transmitted to the refrigerant through the heat shield member 3, is excluded from the system, and is not transmitted to the entrance end of the bundle 40. Also,
/prr for the light transmitted through the quartz rod 1 and the vapor deposited film 2
Since infrared light with wavelengths longer than r is not included, even if this light is incident on the bundle 4, the bundle 4 will hardly absorb the incident light and generate heat.

Band/L/4 focusing adhesive does not deteriorate due to heat. Furthermore, if a liquid such as cooling water is used as the refrigerant, the refrigerant passage 5 will be filled with the liquid, and light will not be diffusely reflected within the passage 5 (
, the amount of incident light does not decrease.

Furthermore, if water is used as the refrigerant, since water has good infrared light absorbing properties, infrared light is absorbed here as well, and more favorable results can be obtained.

Note that similar effects can be obtained even when a large-diameter Kli-core optical fiber is used instead of the fiber bundle 4.

〔Effect of the invention〕

As explained above, the entrance end structure of the light guide for nosewar transmission according to the present invention has a quartz rod and a heat shielding member having a refrigerant passage formed on one end surface of the quartz rod. Since the transmission light guide is placed so as to face the incident end surface, the infrared light component in the incident light is absorbed and removed by the quartz rod, and light that does not contain the infrared light component enters the light guide. This prevents the light guide itself from absorbing the infrared light component in the incident light and generating heat. Furthermore, although the quartz rod that absorbs the infrared light component generates heat, this heat is removed by the coolant flowing through the coolant passage and is not transmitted to the light guide. moreover,
Heat associated with the incident light is also removed by the coolant.

Therefore, with this end structure, the light guide end is not heated, and thermal deterioration of the light guide can be prevented, and the local output from high-output norogen lamps, high-output xenon lamps, etc. can be reduced. Alternatively, high-power laser light can be incident on a problematic (light guide).

Well, if you use a fiber bundle for the light guide,
Light from a light source or optical system that cannot be narrowed down can also enter.

[Brief explanation of the drawing]

The drawing is a schematic cross-sectional view showing an example of the entrance end structure of the present invention. DESCRIPTION OF SYMBOLS 1... Quartz rod, 2... Infrared light blocking vapor deposited film, 3... Heat shielding member, 4... Fiber bundle, 5...・Refrigerant passage.

Claims (2)

[Claims] (1) A quartz rod and a heat shielding member having a refrigerant passage formed on one end surface of the quartz rod are arranged so that the refrigerant passage faces the incident end surface of the power transmission light guide. Structure of the entrance end of a light guide for power transmission. (2) The incident end structure of a power transmission light guide according to claim 1, wherein the quartz rod has an infrared light blocking vapor deposited film formed on one end surface thereof.