Projection lenses having reduced lateral color for use with pixelized panels
AssigneeU.S. Precision Lens Incorporated
InventorsMelvyn H. Kreitzer, Jacob Moskovich
Life of this patent
Estimating the term…
Abstract
Projection lens for use with pixelized panels are provided which consist of a first lens unit which has a negative power and a second lens unit which has a positive power. The V-values and Q-values of the lens elements of the first and second lens units are selected so that the projection lenses can simultaneously have: (1) a high level of lateral color correction, including correction of secondary lateral color; (2) low distortion; (3) a large field of view in the direction of the image (screen); (4) a telecentric entrance pupil; and (5) a relatively long back focal length.
Claims31
A projection lens for forming an image of an object which consists in order from its image end to its object end of:
- (A) a first lens unit U1 having a negative power and comprising three lens elements EP, EN, and EN′, arranged in any order and having focal lengths fU1/P, fU1/N, and fU1/N′, V-values VU1/P, VU1/N, and VU1/N′, and Q-values QU1/P, QU1/N, and QU1/N′, respectively;
- (B) a second lens unit having a positive power;
- and
- (C) an optional field lens unit;
- wherein EN or EN′ is made of glass and wherein:
- fU1/P>0,
- fU1/N<0,
- fU1/N′<0,
- VU1/N>VU1/P,
- VU1/N′>VU1/P,
- QU1/N>0,
- QU1/N>QU1/P,
- QU1/N>VU1/N,
- QU1/N′>0, and
- QU1/N>QU1/P.
A projection lens for forming an image of an object which consists in order from its image end to its object end of:
- (A) a first lens unit U1 having a negative power and comprising two lens elements EP and EN, arranged in any order and having focal lengths fU1/P and fU1/N, V-values VU1/P and VU1/N, and Q-values QU1/P and QU1/N, respectively;
- (B) a second lens unit having a positive power;
- and
- (C) an optional field lens unit;
- wherein EN is made of glass and wherein:
- fU1/P>0,
- fU1/N<0,
- VU1/N>VU1/P,
- QU1/N>0, and
- QU1/P<0.
A projection lens for forming an image of an object which consists in order from its image end to its object end of:
- (A) a first lens unit U1 having a negative power and comprising two lens elements EP and EN, arranged in any order and having focal lengths fU1/P and fU1/N, V-values VU1/P and VU1/N, and Q-values QU1/P and QU1/N, respectively;
- (B) a second lens unit having a positive power;
- and
- (C) an optional field lens unit;
- wherein:
- fU1/P>0,
- VU1/N>VU1/P,
- QU1/N>VU1/N, and
- QU1/N>125.
A projection lens for forming an image of an object which consists in order from its image end to its object end of:
- (A) a first lens unit U1 having a negative power;
- (B) a second lens unit U2 having a positive power and comprising two lens elements E′P and E′N, arranged in any order and having focal lengths fU2/P and fU2/N, V-values VU2/P and VU2/N, and Q-values QU2/P and QU2/N, respectively;
- and
- (C) an optional field lens unit;
- wherein:
- fU2/P>0,
- fU2/N<0,
- VU2/P>VU2/N,
- QU2/P>VU2/P, and
- QU2/P>135.
A projection lens for forming an image of an object composed of pixels, said projection lens consisting in order from its image end to its object end of:
- (A) a first lens unit U1 having a negative power;
- (B) an aperture stop or a pseudo-aperture stop;
- (C) a second lens unit U2 having a positive power and comprising a positive lens elements having a V-value VU2/P;
- and
- (D) an optional field lens unit;
- wherein:
- VU2/P>75, and
- VU2/C>0.1/(p′•F#U2),
- where F#U2 is the f-number of the second lens unit as traced from the object towards the image, p′ is the width of a pixel divided by f0, where f1 is the focal length of the combination of the first and second lens units, and VU2/C is a composite V-value for the second lens unit given by:
- VU2/C=fU2{Σ(VU2/i/fU2/i)}
- where fU2 is the focal length of the second lens unit, fU2/i and VU2/i are the focal length and V-value of the ith lens element of the second lens unit, and the summation is over all lens elements of the second lens unit.
A projection lens for forming an image of an object composed of pixels, said projection lens consisting in order from its image end to its object end of:
- (A) a first lens unit having a negative power and comprising means for correcting the secondary lateral color of the projection lens, said means comprising two lens elements EP and EN, arranged in any order and having focal lengths fU1/P and fU1/N, V-values VU1/P and VU1/N, and Q-values QU1/P and QU1/N. respectively;
- (B) a second lens unit having a positive power;
- and
- (C) an optional field lens unit;
- wherein:
- fU1/P>0,
- fU1/N<0,
- VU1/N>VU1/P,
- QU1/N>0, and
- QU1/P<0.
A projection lens for forming an image of an object composed of pixels, said projection lens consisting in order from its image end to its object end of:
- (A) a first lens unit having a negative power;
- (B) a second lens unit having a positive power;
- and
- (C) an optional field lens unit;
- wherein:
- (i) the projection lens has a half field of view in the direction of the image of at least 25°;
- (ii) the lateral color blur of the projection lens at its full field is less than a pixel for wavelengths in the range from 460 nanometers to 620 nanometers;
- (iii) the distortion of the projection lens is less than 1.0 percent;
- (iv) the projection lens is telecentric in the direction of the object;
- (v) the projection lens is a zoom lens and has a short focal length position;
- and
- (vi) the half field of view, lateral color blur, and distortion are evaluated at the short focal length position.
Dependencies are inferred from the claim text.