| 摘要 |
PROBLEM TO BE SOLVED: To provide a laser scanning optical system which can widen an inspection range by increasing angle of incidence and also shorten WD(working distance). SOLUTION: The laser beam emitted by a laser light source 1 is made to scan in two dimensions by galvanomirrors 2a and 2b, and imaged as a spot through a lens 3 to make a scan on a scanning surface 6. Wedge prisms 10a-10d which transmit and deflect the laser beam are arranged behind the lens 3. The galvanomirrors 2a and 2b are arranged nearby the front focus position of the lens 3 so as to form a telecentric optical system, so that a laser beam having a scanning angle at which the laser beam passes through the wedge prisms 10a-10d is made incident obliquely on the scanning surface and a laser beam having a scanning angle at which it does not pass through the wedge prisms 10a-10d is made incident perpendicularly on the scanning surface. The angle of refraction of the wedge prisms 10a-10d is large, so the inspection range can be widened by making the angle of incidence large and the WD(working distance) can be shortened. |
