| 摘要 |
PURPOSE:To perform high-accuracy shearing by fitting a corner cube prism to a fitting base which is fitted rotatably on one end side of a link and fitting a driving part for shearing to a freely rotatable and movable base on the other end side. CONSTITUTION:A reference mirror is placed at the position of a body 35 to be measured and a prism 26 is adjusted in its height direction so that interference fringes formed with light beams generated by reflecting the laser light from an He-Ne laser 31 by corner cube prisms 26 and 37 are in one color. At this time, links 16 and 17 of the shearing device 30 are held horizontally. When the interference fringes are in the one color, the reference mirror is replaced with the body 35 to be measured and a voltage is applied to a laminate piezoelectric element 29 to cause displacement by a shear quantity. When the distance between the rotary shafts of the links 16 and 17 is 30mm and the shear quantity is 30mum, the displacement quantity of the movable base 20 and prism 29 in an X-axial direction is 1.5X10<-2>mum and of order which can be ignored. For the purpose, the Y-axial shearing of the prism 26 is accurately performed and current interference fringes are read by an area sensor 39 to accurately measure the body 35 to be measured. |
