| 摘要 |
PURPOSE:To increase the accuracy for setting of the scale gap of an optical encoder, by applying a necessary sinking process to a transparent base material to obtain a main scale and forming a secondary scale having a checkered pattern on the main scale with a wear-resistant lubricant thin film formed on the rubbing face. CONSTITUTION:A sinking process is applied with a desired degree of scale gap to a transparent base material 39 of glass, quartz, etc. having the satisfactory flatness, by the etching process. Thus a recessed face 40 is formed. Then an opaque thin film 41a of Cr, TiC, TiN, etc. is formed on the face 40 by the sputtering process, etc. A checkered pattern 41 is formed by the etching process and with use of a prescribed mask. Then, a wear-resistant lubricant thin film 42 of TiC, etc. is formed on the film 41a. In such way, an optical absolute encoder is obtained with high accuracy. |
