| 摘要 |
PURPOSE:To prevent positional deviation and angular deviation between a light source and a collimating lens by providing a cylindrical frame of outer diameter (b) and coefficient of linear expansion gamma that supports the collimating lens and a polyhedron of the same material quality with the supporting member. CONSTITUTION:The center axis of a collimating lens 9 fixed by a cylindrical frame 10 generates parallel movement by (b/2)gammaDELTATX(1/sintheta) on a straight line connecting the center axis and a point N for change of DELTAT. In the case of change of DELTAT, the direction of parallel movement of the optic axis of a light source 6 and the direction of parallel movement of the center axis of the lens 9 are perfectly equal. In this case, a polyhedron 11 is formed selecting the distance d to satisfy alphad=gammab, difference of amount of parallel movement becomes '0'. Accordingly, the amount of parallel movement of optic axis of the light source 6 fixed by the polyhedron 11 and the amount of parallel movement of center axis of the lens 9 fixed by the frame 10 for change of DELTAT are the same in the direction of movement and amount of movement, and positional deviation and slanting of the axis in relative positional relation between the two do not occur regardless of change of DELTAT. |
