JP3002212B2 - Reflector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an optical component, and more particularly, to a reflecting mirror that efficiently reflects light having a wavelength in an infrared region represented by a carbon dioxide laser.

(Prior Art) In general, a carbon dioxide laser processing machine has a reflecting mirror,
A planar, spherical or aspherical reflecting mirror is used. The main characteristic required as a material of a reflecting mirror that reflects laser light having a wavelength in the infrared region oscillated from this carbon dioxide laser processing machine is that the surface has little absorption at a wavelength of 10.6 μm, that is, high reflectivity, The heat generated in the above process is quickly dissipated, ie, high thermal conductivity, not damaged by local heating by laser light, ie, heat resistance, chemical stability against surface cleaning, and good workability. Therefore, as a material satisfying this condition, copper (Cu) is usually used.
Alternatively, molybdenum (Mo) is often used.

(Problems to be Solved by the Invention) However, the reflecting mirror made of copper has the advantages of good workability, a mirror surface obtained by cutting with a diamond tool, and good thermal conductivity and a large cooling effect. On the other hand, it has the disadvantage that it is easily scratched, and its melting point is as low as 1083 ° C, so that the dissolved matter is easily attached. On the other hand, molybdenum reflectors are harder and less susceptible to damage than copper reflectors. It has a drawback that the workability is poor and it is particularly difficult to mirror-process a curved surface or a unique shape. In short, a reflecting mirror made of copper and a reflecting mirror made of molybdenum have advantages and disadvantages, and a reflecting mirror having both advantages, that is, having a light resistance without sacrificing reflectance has been desired.

The present invention has been made in view of the above circumstances, and has as its object to provide a reflector having both the advantages of a copper reflector and the advantages of a molybdenum reflector.

(Means and Actions for Solving the Problems) The reflecting mirror of the present invention is a diamond tool with 4 to 5 nmR.
It has a reflective surface mirror-cut to the surface roughness of a, has a main body made of copper or copper alloy or aluminum or aluminum alloy, and has a surface roughness of 4 to 5 nmRa applied on the reflective surface Since it has a total reflection part made of a platinum film, it has excellent laser reflection characteristics and excellent laser beam resistance, and is used as a total reflection mirror for carbon dioxide gas laser processing machines. Even so, a high reflectance can be stably maintained over a long period of time.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a reflecting mirror (M) of this embodiment.
The reflecting mirror (M) is a total reflecting mirror for a high-output continuous wave carbon dioxide laser beam machine, and in this case, a concave spherical mirror is exemplified. The reflecting mirror (M) includes a thin plate-shaped main body (1) and a total reflection film (2) attached on the main body (1). The main body (1) is made of oxygen-free copper, and has a size of, for example, a plate having a diameter of 1 inch × 1/4 inch to 4 inches × 1 inch. The shape accuracy is λ / 10 to 40 (λ = 10.6μ
m), the surface roughness is about 4 to 5 nmRa. The reflecting surface (3) forming the concave spherical surface of the main body (1) is manufactured by a diamond mirror-cutting method. The conditions for obtaining a high quality mirror surface by this diamond mirror surface cutting method are that the oxygen-free copper material is dense and free from defects, the processing machine has high precision, and the diamond tool uses a high quality natural tool. The cutting edge formed by the rake face and flank face at the tip of the cutting tool is sharp, the roughness is smooth, and cutting conditions are sufficiently selected. On the other hand, the total reflection film part (2)
Is a film having a thickness of about 1 μm formed on the reflecting surface (3) of the main body (1) by a sputtering method, and is made of molybdenum (Mo). In this sputtering, as shown in FIG. 2, when ions (4) such as Ar are collided with a target (5) made of molybdenum (6), molybdenum atoms constituting the surface of the target (5) are converted. This utilizes a phenomenon in which the mutual bonding force is shaken off and jumps out. As the sputtering method, there are a high frequency sputtering method, a reactive sputtering method, a bias sputtering method, a magnetron sputtering method, an asymmetric AC sputtering method, and the like. In order to form the molybdenum total reflection film portion (2), High frequency sputtering is preferred. The resulting total reflection film part (2) has a shape accuracy of λ / 10 to 40 (λ = 10.6 μm) and a surface roughness of about 4 to 5 nmRa. It is almost the same level as the reflection surface (3).

Next, in the reflecting mirror (M) having the above configuration, when a laser beam (7) having an infrared wavelength emitted from a carbon dioxide laser processing machine is incident on the reflecting mirror (M), the laser beam (7) Are reflected by the total reflection film portion (2). The reflectance at this time was about 99%. In addition, in this case, since the laser beam (7) is directly incident on the total reflection film portion (2) made of molybdenum having a melting point of 2640 ° C., the reflector (M) in this case has a smaller damage than the copper reflector. Difficult to adhere, thermal strain
It has the advantage that it is resistant to thermal damage, has excellent corrosion resistance, has a high melting point, and hardly adheres to dissolved and scattered matter. In addition, since the main body (1) is made of oxygen-free copper, a mirror surface having a surface roughness of about 4 to 5 nmRa can be obtained by cutting with a diamond tool,
In addition, there is an advantage that the heat conductivity is good and the cooling effect is large.
Therefore, even if the reflecting mirror (M) having both the advantages of copper and molybdenum is used as a total reflecting mirror for a carbon dioxide laser beam machine, a high reflectance can be stably maintained for a long period of time. In other words, it is a long-life reflecting mirror having both laser beam proof strength and laser reflecting property.

In the above embodiment, aluminum (Al) may be used as the material of the main body (1). In addition, an alloy of copper or aluminum may be used. Platinum (Pt), tungsten (W) are used as the material of the total reflection film (2).
May be used. Further, as a processing method of the reflection surface (3), a polishing processing method may be used. Furthermore, as a method of forming the total reflection film portion (2), another method such as an ionization vapor deposition method may be used. In addition, the reflecting mirror of the present invention,
It can also be applied to convex spherical mirrors, plane mirrors, paraboloids of revolution, segment mirrors, and the like. Note that “shape accuracy” in the examples is synonymous with “geometric deviation” in B0621 of Japanese Industrial Standards (JIS).

[Effect of the Invention] The reflecting mirror of the present invention has good laser reflection characteristics and also has excellent laser beam proof strength. Therefore, even when used as a total reflection mirror for a carbon dioxide laser processing machine, a high reflectance can be stably maintained over a long period of time.

[Brief description of the drawings]

FIG. 1 is a sectional view of a reflecting mirror according to an embodiment of the present invention, and FIG. 2 is an explanatory view of the manufacturing method. (M); a reflecting mirror, (1); a main body, (2); a total reflection film, (3); a reflecting surface.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-144304 (JP, A) JP-A-63-282701 (JP, A) JP-A-1-300203 (JP, A) JP-A-2- 63002 (JP, A) JP-A-1-303404 (JP, A) JP-A-1-309004 (JP, A) JP-A 1-312504 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) G02B 5/00-5/136

Claims (2)

(57) [Claims] 1. A body made of copper or a copper alloy or aluminum or an aluminum alloy having a reflecting surface mirror-finished to a surface roughness of 4 to 5 nm Ra with a diamond bite, and a surface coated on the reflecting surface. ~ 5nmRa
A total reflection portion made of a platinum film having a surface roughness of 1. 2. A diamond bite having a surface roughness of 4 to 5 nm Ra and an oscillation wavelength of a laser beam emitted from a carbon dioxide laser oscillator as λ. A main body made of copper or a copper alloy or aluminum or an aluminum alloy having a reflecting surface mirror-cut to a shape accuracy of λ / 10 to 40, and a platinum film deposited on the reflecting surface by sputtering or ionization vapor deposition 4-5nmRa consisting of
When the surface roughness of the laser beam and the oscillation wavelength of the laser beam emitted from the carbon dioxide laser oscillator are set to λ, the total reflection with a shape accuracy of λ / 10 to 40 with respect to a desired geometrical contour surface determined by an accurate dimension And a reflector.