Abstract: A projection lens for use with LCD panels is provided. The lens has a first lens unit which includes a strong negative lens element having an aspherical surface which provides distortion correction, and a second lens unit which includes a first lens subunit separated by an airspace from a second lens subunit, wherein the first lens subunit has a strong positive power and the second lens subunit has a weaker power. The second lens subunit can include a negative lens element, followed by a positive lens element, followed by a plastic lens element having an aspherical surface. The projection lens has a field of view of at least 35° so that the overall projection lens system has a compact size.

Abstract: The device includes a) flat mirror (7) formed by adjacent areas (5i, 6i) that are alternately transparent and reflecting with parallel and straight lines of demarcation, b) identical first (4) and second (4′) reflection holograms, each delivering at least one diffracted beam with a predetermined spectral composition, c) illuminating source (1) for illuminating said holograms (4, 4′) at normal incidence by the intermediary of said mirror (7), said holograms (4, 4′) being arranged symmetrically with respect to the plane of said mirror (7) in such a way as to be illuminated by the intermediary of transparent (6i) and reflecting (5i) strips, respectively, of mirror (7), and in such a way that the beams diffracted by the first and second holograms are reflected and transmitted, respectively, by reflecting (5i) and transparent (6i) strips, respectively, of mirror (7), in order to be combined into a continuous light beam with said spectral composition.

Abstract: Projection lens systems (13) for use in CRT projection televisions (10) are provided. From the screen side, the systems have three lens units (U1, U2, U3), the first two units (U1, U2) forming a retrofocus lens and the third unit (U3) being associated with the CRT during use and serving to correct field curvature. At its screen end, the first lens unit (U1) has a negative element (E1) which has a screen surface (S1) which is concave to the screen. The second lens unit (U2) has two positive subunits (US1, US2), the first subunit (US1) being a color correcting doublet composed of glass and the second subunit having a positive lens element (E2) at its screen end. The projection lens systems are fully color corrected, have f/#'s of 1.0 for an infinite conjugate, have half fields of view of at least 25°, and are economical to manufacture.

Abstract: A projection lens for use with LCD or DMD panels is provided. The lens has three lens units, the first unit having a weak power and at least one aspheric surface, the second unit having a positive power, a high dispersion negative lens element, and a low dispersion positive lens element, and the third unit having a negative power, a positive meniscus lens element and a negative lens element. The projection lens satisfies the following relationships: f0/|f1|<0.6; and BFL/f0>0.3 where (i) f0 is the effective focal length of the combination of the first, second, and third lens units; (ii) f1 is the effective focal length of the first lens unit; and (iii) BFL is the back focal length of the combination of the first, second, and third lens units for an object located at infinity along the long conjugate side of the projection lens.

Abstract: Projection lens systems (13) for use in projection televisions are provided. The systems are characterized by a screen side lens unit (U1) which: (1) has a weak optical power; (2) has a negative, aspherical lens element composed of a high dispersion material; and (3) has a positive lens element which is composed of a low dispersion material.

Abstract: An apparatus and method for locking a focus position of a lens assembly without causing the lens cell to tilt, comprising: a spacer interposed between the lens cell and the focus mount. The spacer is received into a sleeve that is integral with the focus mount. The sleeve projects radially outward from the focus mount such that the spacer can be raised and lowered radially with respect to the focus mount. The spacer has a cylindrical body with a radial flange at one end. Moreover, the spacer has two ridges that extend downward from a lower surface of the flange, each of which is received into a corresponding groove on the sleeve, thus, preventing the spacer from rotating within the sleeve. The spacer also has an upwardly raised rim extending from an upper surface of the flange. The rim is slidably secured into a slot of the focus mount, which prevents lateral movement of the spacer.

Abstract: Coupling fluids for use in optically coupling a projection lens system of a projection television to a cathode ray tube (CRT (16)) are provided. The fluids have: (1) at least one polymer having a siloxane backbone, i.e., at least one polymer having a —Si—O—Si—O—Si— backbone, and (2) methyl, phenyl, and hydrophilic groups attached to the silicon atoms of the backbone. The fluid can be composed of a single siloxane polymer having methyl, phenyl, and hydrophilic side groups or a mixture of a siloxane polymer having methyl and phenyl side groups with a siloxane polymer having methyl and hydrophylic side groups. The index of refraction of the fluid is preferably greater than 1.52 so as to minimize reflections at the interface between the fluid and the faceplate (17) of the CRT (16).

Abstract: Device for elimination of the zero order beam emerging from holograms illuminated in polarized light includes a birefringent plate (5) illuminated by both said zero order beam (3) and by a diffracted beam (4) emerging from the hologram (2). The plate is arranged and sized such that one of the beams (3, 4) emerges from the plate with its plane of polarization not appreciably rotated and such that the other of said beams emerges with its plane of polarization rotated by 90°. The device further includes a polarizer (9) illuminated by the beams (3′, 4′) emergent from the birefringent plate (5), the polarizer having its plane of maximum transmittance parallel to the plane of polarization of the diffracted beam emerging from the birefringent plate as beam (4′). The device finds industrial applicability in the optical systems of video image projectors employing active matrix liquid crystal cells.