| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection device capable of performing cross line alignment accurately, based on index image. SOLUTION: This device is provided with a rotating screen 3 having cross lines 31 and provided rotatably, and an index image projection optical system for projecting an image 6 onto the rotating screen 3. The image 6 comprises a bright part 61 and a line segment-shaped dark part 62 as the index image. The cross line alignment is performed, by superposing a line segment 31A constituting the cross lines 31 on the dark part 62. The line segment 31A and the dark part 62 have no parallax between them, because they are formed on the rotating screen 3 together, and the cross-line alignment can be performed accurately, and thereby the dimension measurements of a work can be performed accurately. COPYRIGHT: (C)2006,JPO&NCIPI
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