Photocopying – Projection printing and copying cameras – Step and repeat
Patent
1983-04-07
1985-03-26
Gonzales, John
Photocopying
Projection printing and copying cameras
Step and repeat
355 55, 355 56, 356399, 356400, G03B 2742, G03B 2752
Patent
active
045069778
ABSTRACT:
A transfer apparatus comprises a projection device operable with a photomask having a semiconductor circuit pattern therein and includes a projection lens for projecting the image of the photomask to a photosensitive member sensitive to the image of the photomask projected by the projection lens. The apparatus further includes an illuminating device for illuminating the photomask, a memory circuit for storing the time characteristic .DELTA.l of a focus error occurring in the projection lens due to the exposure light from the photomask having passed through the projection lens, a history detector for detecting the illuminating history to/t of the illuminating device, a transmission signal forming device for forming a transmission signal regarding the transmission factor .tau. of the photomask used, a length measuring device for measuring the length of a part of the optical path between the photomask and the photosensitive member, an operation circuit for calculating a proper value in accordance with the output of the memory circuit, the output of the history detector and the transmission signal, and an adjusting device for adjusting the length of the optical path of the projection device until the proper value and the value measured by the length measuring device are in accord with each other.
REFERENCES:
patent: 4084903 (1978-04-01), Pircher
patent: 4087180 (1978-05-01), DiNatale
patent: 4140392 (1979-02-01), Lacombat et al.
patent: 4155642 (1979-05-01), Lacombat
patent: 4236818 (1980-12-01), Fauchier
patent: 4274732 (1981-06-01), Thurm et al.
patent: 4371259 (1983-02-01), Howitt
patent: 4383757 (1983-05-01), Phillips
Kosugi Masao
Sato Hiroshi
Yabu Shuichi
Canon Kabushiki Kaisha
Gonzales John
Rutledge Della J.
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