OPTICAL SYSTEM FOR PROJECTION TYPE ON-BOARD DISPLAY Russian patent published in 2014 - IPC G02B23/10 G02B27/01 

FIELD: physics.

SUBSTANCE: optical system has a concave spherical beam-splitting mirror with curvature radius R, a flat beam-splitting mirror mounted with inclination to the optical axis, a spherical diffusing screen, a projection lens, a liquid crystal display and a condenser. The projection lens consists of two components and an aperture diaphragm (AD). The first component is a single negative meniscus whose convex side faces a diffusion screen with curvature radius R/2. The second component is made of a negative glued lens and a double-lens positive element comprising a biconcave and a biconvex lens. The AD is placed between the first and second components in the front focus of the second component into which the positive glued lens is directed, said positive glued lens being placed between the AD and the negative glued lens, and a positive meniscus lens, whose concave side faces the spherical diffusion screen. Optical power values of the lenses satisfy conditions given in the claim.

EFFECT: high flight safety by preventing loss of information from the display when the head of the pilot moves both along and perpendicular to the optical axis.

1 dwg, 1 app