PURPOSE: To attain the detection for a micropattern such as a pattern of an LSI circuit, etc. with a high speed and high S/N, by using only a local arc part having high luminance and at the area close to the electrode of a short arc discharging lamp to a light source.
CONSTITUTION: The beams of a lamp 1 are collected by a collector lens 2 and then reflected by a mirror 3 to form a light source image 4. This image 4 illuminates a subject 6 which is set at the focal position of a condenser lens 5. The subject 6 is magnified by a lens 7 and forms an image 8. The luminous intensity is constant on the surface of the subject 6 regardless of the focal distance fO of the lens 5 when the size of the imge 4 is set at l1, the luminous intensity is dI and the size of the illuminating part of a subject (b) is d1, respectively. Thus only a local arc part having high luminance and at the place close to the electrode of a short arc discharging lamp to a light source in order to increase the luminous intensity of illumination.
AKIYAMA NOBUYUKI
OOSHIMA YOSHIMASA
FUSHIMI SATOSHI
| JPS4430093Y1 | 1969-12-12 |
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