3679297 is referenced by 9 patents and cites 6 patents.

An aircraft head-up display is projected from symbol-markings borne by two complementary color filters superimposed in the light-path from an electric lamp. An horizon-line marking of the first filter has the color of the second filter bearing a flight-vector marking, and vice versa, but either marking may be transparent. The filters are separately driven to follow aircraft movements with the symbol-images simulating the true horizon and flight-vector. A third filter with glide-slope marking may be carried adjustably with the first filter to allow modification of indicated glide-slope below the horizon.

Display systems
Application Number
Publication Number
Application Date
February 26, 1970
Publication Date
July 25, 1972
Walker Christopher H C
Searle Simon M St L
G02b 05/22
G09f 09/00
G03b 21/00
G02B 27/00
G02B 27/01
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