| 摘要 |
PURPOSE:To prevent an image formation reference position from deviating and to accurately maintain optical axis accuracy by providing a roll which rolls on a guide member for moving a moving table in the direction of an optical axis at an end part of a guide rod. CONSTITUTION:On the opposite sides of a 1st moving table 30 from bearings 30A, rolls 33 are fitted to tips inserted into the bearings through the shaft parts of guide rods 15. The rolls 33 are positioned on the same plane with the axis positions of the guide rod 21 on the 1st moving table 30 and guide rods 15 on a 2nd moving table 31. The 1st moving table 30 is therefore suspended and supported by a rail 23 through the guide rod 21 on the 2nd moving table 31 and by the guide rod 21 on the side of the 1st moving table 30. Namely, the rigidity of the guide rod 15 which supports the 2nd moving table 31 slidably is set large to prevent the 1st moving table 30 from being loaded directly with the weight of respective components including the 1st moving table 30, thereby eliminating inclination due to the deflection of the coupling part. |
