| 摘要 |
PURPOSE:To form a minute pattern of especially 0.8-0.5mum or below without causing distortion in a projection lens by securing the light transmittance of the projection lens on a high level that it does not generate distortion by the application of a low-pressure mercury lamp. CONSTITUTION:A quartz glass ingot is manufactured by hydrolyzing and fusing high purity of silicon tetroxide directly by a flame method, and the inside striae are removed, and the distortion is removed by removed heating it so as to manufacture an optical quartz glass member. This glass member does not generate a fluorescent light by the irradialion by the use of a low-pressure mercury lamp which has a wavelength of 254nm, and has equality such as that the refractive index difference is 5X10<-8> in a light transmissive area. A minute pattern which has a pattern width of 0.5mum or below by forming the pattern image being obtained by entering a KyF laser beam into the pattern face on a recticle through the projecting lens 14 manufactured out of such quartz glass member. |
