Projection lenses for use with reflective pixelized panels
AssigneeCorning Precision Lens
InventorMelvyn H. Kreitzer
Life of this patent
Estimating the term…
Abstract
Projection lenses (13) for use with pixelized panels (PP) are provided. The projection lenses have a negative first unit (U1) which has at least one aspheric surface and a positive second unit (U2) which has three subunits (US1, US2, US3) which have a positive/negative/positive configuration. The lens' aperture stop (AS) is located at the short conjugate end of the lens and is either in the third subunit (US3) or close to that subunit. The lenses are particularly well-suited for use in the manufacture of compact projection systems which employ side illumination of a reflective pixelized panel.
Claims17
A projection lens having an aperture stop, an optical axis, a long conjugate side, a short conjugate side, a power Φ0, and a back focal length BFL, said projection lens being adapted to form an image of a pixelized panel and consisting in order from said long conjugate side to said short conjugate side of:
- (A) a first lens unit having a power ΦU1 and comprising at least one aspheric surface;
- and
- (B) a second lens unit having a power ΦU2 and consisting in order from said long conjugate side to said short conjugate side of:
- (i) a first lens subunit having a power ΦS1;
- (ii) a second lens subunit having a power ΦS2 and an overall meniscus shape which is concave towards the short conjugate;
- and
- (iii) a third lens subunit having a power ΦS3 and a surface S3 at its long conjugate side;
- wherein:
- (a) ΦU1<0;
- (b) ΦU2>0;
- (c) ΦS1>0;
- (d) ΦS2<0;
- (e) ΦS3>0;
- (f) BFL•Φ0≧1.0;
- and
- (g) the aperture stop is either within the third lens subunit or spaced from surface S3 in the direction of the long conjugate by a distance D which satisfies the relationship:
- D•Φ0≦0.1.
Dependencies are inferred from the claim text.