| 摘要 |
PURPOSE:To obtain a high reflectivity and to prevent the deformation at the time of working of a specular surface, etc., by diffusion-joining an outer peripheral layer to the outer peripheral surface of an aluminum alloy body formed of an aluminum alloy having a high Young's modulus. CONSTITUTION:The outer peripheral layer 2 including specular surfaces is formed of a magnesium or magnesium alloy having an excellent reflection characteristics to laser light. This outer peripheral layer 2 is diffusion joined to a stock body 1 formed of the Al alloy material having the high Young's modulus. The outer peripheral 2 worked with the specular surfaces constituting the laser light reflecting surface in such a manner is diffusion joined to the outer peripheral surface of the body 1 formed of the Al alloy having the high Young's modulus and, therefore, the layer is hardly deformed by the cutting load exerted thereon at the time of working a reference plane or the specular surfaces and the required accuracy of the surface inclination is easily assured without increasing the thickness of the stock. The surface inclination to the reference plane is hardly generated in this way and the polygon mirror having the high accuracy is easily produced. |
