| 摘要 |
PROBLEM TO BE SOLVED: To provide an autofocus device and autofocus method which uses a pattern projection technique and is capable of performing focusing at a higher speed than in conventional practices.SOLUTION: An autofocus device 1 includes a light source 11 which emits light toward the surface of a sample, a pattern projection plate 12 which is arranged between the light source 11 and the sample S and projects a predetermined pattern image onto the surface of the sample S, a second imaging unit 17 which captures the pattern image projected on the surface of the sample S, and a control unit 50 that calculates the contrast of the image captured by the second imaging unit 17 and moves the sample S in a direction which focuses the second imaging unit 17 on the surface of the sample S on the basis of the calculated contrast. In an optical path that runs from the light source 11 via the pattern projection plate 12 and the sample S to reach the second imaging unit 17, an optical path length is changed within a plane orthogonal to the optical path. |
