Telecentric lens systems for forming an image of an object composed of pixels
First Claim
1. A telecentric lens system having an aperture stop and a telecentric pupil, said system comprising in order from its long conjugate side to its short conjugate side:
- (a) a first lens unit which has a negative power and comprises a negative lens element whose strongest surface is convex to the long conjugate side of the system;
(b) a second lens unit which is of weak optical power and comprises two meniscus elements whose concave surfaces face each other, the system'"'"'s aperture stop being located between the meniscus elements and each meniscus element having at least one aspheric surface; and
(c) a third lens unit which has a positive power and comprises means for correcting the chromatic aberrations of the system, said third lens unit forming the system'"'"'s telecentric pupil by imaging the aperture stop.
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Accused Products
Abstract
Telecentric lens systems for use with pixelized panels, such as LCD or DMD panels, are provided. The systems have a long aperture stop to object distance (ASOD) and a high level of aberration correction, including a high level of lateral color correction. Preferably, the systems also have a low f-number and are wide angle. The systems include a negative first unit which produces the long ASOD, a weak second unit which includes two meniscus elements which surround the system'"'"'s aperture stop, and a positive third unit which images the aperture stop to form the system'"'"'s telecentric pupil.
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Citations
18 Claims
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1. A telecentric lens system having an aperture stop and a telecentric pupil, said system comprising in order from its long conjugate side to its short conjugate side:
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(a) a first lens unit which has a negative power and comprises a negative lens element whose strongest surface is convex to the long conjugate side of the system; (b) a second lens unit which is of weak optical power and comprises two meniscus elements whose concave surfaces face each other, the system'"'"'s aperture stop being located between the meniscus elements and each meniscus element having at least one aspheric surface; and (c) a third lens unit which has a positive power and comprises means for correcting the chromatic aberrations of the system, said third lens unit forming the system'"'"'s telecentric pupil by imaging the aperture stop. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A projection television system comprising a pixelized panel, a screen, and a lens system for forming an image of the pixelized panel on the screen, said lens system having an aperture stop and a telecentric pupil, and the distance between the aperture stop and the pixelized panel being at least about 2.5 times the lens system'"'"'s focal length, wherein the lens system comprises, in order from its long conjugate side to its short conjugate side:
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(a) first lens unit which has a negative power and comprises a negative lens element whose strongest surface is convex to the long conjugate side of the system; (b) a second lens unit which is of weak optical power and comprises two meniscus elements whose concave surfaces face each other, the system'"'"'s aperture stop being located between the meniscus elements and each meniscus element having at least one aspheric surface; and (c) third lens unit which has a positive power and comprises means for correcting the chromatic aberrations of the system, said third lens unit forming the system'"'"'s telecentric pupil by imaging the aperture stop. - View Dependent Claims (18)
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Specification