Title:
Variable density window
United States Patent 2237566
Inventors:
Land, Edwin H.
Publication Date:
04/08/1941
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Export Citation:
Assignee:
POLAROID CORP
Primary Class:
Other Classes:
160/26, 160/98, 160/91, 359/500, 52/786.120, 49/63, 52/307
International Classes:
G02B27/28