OPTICAL PROJECTION SYSTEM Russian patent published in 2014 - IPC G03B21/10 G02B27/18 H04N5/74 

FIELD: physics.

SUBSTANCE: optical system magnifies an image formed by an image modulator and projects said image on a screen. The optical system includes an optical lens system consisting of at least one lens with a positive optical power, having a single optical axis and which forms almost parallel beams coming from the image modulator, an aperture diaphragm situated near the back focal plane of the optical lens system, a catadioptric optical system consisting of a concave mirror and at least one lens, having a single optical axis and which forms an intermediate image in front of the concave mirror. The following relationships are satisfied: $$0.1\le \left|f_2^{\text{'}}/f_1^{\text{'}}\right|\le \mathrm{1000,}$$ 4≤β_M/β_L≤25, Θ1>20°, where $$f_1^{\text{'}}$$ is the focal distance of the optical lens system; $$f_2^{\text{'}}$$ is the focal distance of the catadioptric system; β_M is magnification of the concave mirror; β_L is magnification of the system comprising all lenses; Θ₁ is the smallest angle of incidence of the beam on the screen.

EFFECT: reduced dimensions of components, improved image quality and improved comfort owing to projection of the image sufficiently higher from the projector.

12 cl, 10 dwg, 3 tbl