| 摘要 |
PURPOSE:To correct a shift easily by a small number of parts, by providing a mounting means to an optical base and attaching a shifting means to the mounting means for shifting parallel beams in a predetermined direction. CONSTITUTION:When the center of the pattern of the projected light from an objective lens 10 is positioned in an area 22 or 23, a radial shift correcting plate 20 is inserted to a first or a second mounting groove 11 or 12, whereby the shift is corrected. If the center of the pattern of the projected light of the objective lens 10 is in an area 24 or 25, a tangential shift correcting plate 30 is inserted to a third or a fourth mounting groove 13 or 14, whereby the shift is corrected. Moreover, when the center of the pattern of the projected light of the objective lens 10 is in an area 26, 2?, 28 or 29, after the shifting direction of the parallel luminous flux is determined, the radial shift correcting plate 20 should be inserted into the first or second mounting groove 11 or 12, alternatively, the tangential shift correcting plate 30 should be inserted to the third or fourth mounting groove 13 or 14. |
