Projection exposing apparatus

Details Projection exposing apparatus Projection exposing apparatus

1993-09-02

1995-06-13

Nelms, David C.

Radiant energy

Photocells; circuits and apparatus

Photocell controls its own optical systems

356401, G01N 2186

Patent

active

054245524

ABSTRACT:
A projection exposing apparatus for detecting a state of focus at two or more places in exposure region of a projection optical system by a focus state detection device. In accordance with the result of the detection of the focus state at the two or more places, the image forming characteristics of the projection optical system are measured by an image forming characteristics measuring device. A first pattern extending in the sagittal direction and a second pattern extending in the meridional direction are formed so that the focus state is measured by light beams transmitted these patterns and therefore the astigmatism, eccentricity or the spherical aberration is obtained so as to be corrected.

REFERENCES:
patent: 4558949 (1985-12-01), Uehara et al.
patent: 4629313 (1986-12-01), Tanimoto
patent: 4650983 (1987-03-01), Suwa
patent: 4666273 (1987-05-01), Shimizu et al.
patent: 4952815 (1990-08-01), Nishi
patent: 5117254 (1992-05-01), Kawashima et al.

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