| 摘要 |
PURPOSE:To hold a scale at right angles regardless of the curvature of a frame body and to measure with high precision by adhering a scale holding member which has two guide surfaces to the frame body, and pressing the scale against the member with a rubber rod and adhering it fixedly. CONSTITUTION:The main scale holding member 30 which has two guide surfaces 30A and 30B and a detaining part 30C is adhered and fixed to the frame body 14 at a specific pitch with an elastic adhesive 32. Then, the main scale 10 while pressed against the guide surface 30A with the rubber rod 12 is adhered fixedly to the holding member 30 with an elastic adhesive 34. Consequently, the frame body 14 need not be used as a position reference, and even if the frame body 14 curves, the main scale 10 is held at right angles and the difference in thermal expansion between the frame body 14 and scale 10 is absorbed to take a high- precision measurement. |
