Abstract: A lens assembly especially adapted for mounting in an environment subject to variable temperatures, such as a projection television set, including an automatic thermal focus adjustment. A lens mount is formed from a material having a first coefficient of thermal expansion and carries at least one lens. A focus mount is coupled to the lens mount and is formed from a material having a second coefficient of thermal expansion different from the first coefficient of thermal expansion. Adjustment and locking structure couples the lens mount to the focus mount and allows the lens mount to be axially adjusted relative to the focus mount and then locked in position. In use, the relative axial positions of the lens mount and focus mount automatically change to move the lens in response to a temperature change in the environment of use and after being locked in position with the adjustment and locking structure.

Abstract: A light engine (9) for a projection display is provided which employs: 1) at least one light source (25), 2) at least one TIR prism assembly (13), and 3) at least one digital micromirror device (15), wherein: (a) the illumination path (55) between the light source (25) and the prism assembly (13) is unfolded, i.e., the illumination path is free of fold mirrors; and (b) the angle &ggr; between the illumination path (55) and the device's horizontal axis (53) is preferably less than or equal to about 20°.

Abstract: An illumination polarization conversion system is provided in which unpolarized light from a source (e.g., a lamp (10) and a light integrator (16)) is separated by a polarization converting relay (13) into first and second parts (e.g., S-polarized and P-polarized light) and the polarization of one of the parts is converted to the polarization of the other part (e.g., the S-polarized light is converted to P-polarized light). The converted and non-converted parts are then used to illuminate an object, such as, a polarization converting pixelized panel (12). The polarization converting relay (13) preferably has a telecentric or near telecentric exit pupil formed by placing a hard aperture stop substantially in the back focal plane of a lens unit (L3) located at the light exiting end of the relay (13).

Abstract: A tilted polarization splitter (13) for use with a projection lens (15) and a light modulating panel (11) is provided. The polarization splitter has an ultra thin substrate (14) whose thickness is chosen so that the depth of focus of the projection lens in imager space is greater than the astigmatism produced by the splitter at its tilted angle. The polarization splitter can be a wire grid polarizer, polarization coating, or birefringence film carried by or formed on the ultra thin, plane parallel plate substrate.

Abstract: An electronic (e.g., LCD) projector combines multiple projection lens assemblies with equal color component optical path lengths to provide improved display images and a compact arrangement. In one implementation, the projector includes a successive pair of angled dichroic mirrors that fold the red and blue color components of light in opposed directions. The green color component of light passes through the dichroic mirrors toward a pixelated electronic light modulator, such as a liquid crystal display, and an associated projection lens assembly. The red and blue color components of light are each folded again to propagate parallel with the green color component toward a pixelated electronic light modulator, such as a liquid crystal display, and an associated projection lens assembly. The separate projection lens assemblies are arranged in a non-linear, close-packed arrangement to receive the color components of light.

Abstract: Apparatus and methods for mounting an optical element to a mounting plate in an optical system. The optical element is adhesively bonded with a surface on the mounting plate by a radiation-curable adhesive and a radiation-transmissive member that provides an unobstructed optical path in the mounting plate for curing the radiation-curable adhesive. The adhesive accommodates differences in thermal expansion between the material forming the mounting plate and the material forming the optical element so as to maintain the position and angular orientation of the optical element relative to the mounting plate and so as to prevent damage to the optical element. The formulation of the adhesive forming the adhesive couplings may incorporate spacer elements operative for maintaining the spacing and parallelism between the optical element and the mounting plate.

Abstract: Illumination systems (11) are disclosed which provide scrolling progressive color change on a liquid crystal panel (21), such as a LCoS panel. The systems use transmissive color filters (30, 31, 33) which form an assembly (13) which is rotated about a rotation axis (37). Incident light from a light source (15, 17) passes through the filters and reflects from a reflecting surface (39). As a result of this reflection, the system's optical axis (41, 43) is turned from an orientation substantially perpendicular to the rotation axis to an orientation which does not intersect a filter. Such turning of the optical axis allows colored light to be easily removed from the assembly and avoids problems with color mixing at boundaries between filters as occurs for systems in which light passes through two filters.

Abstract: A polishing system for polishing a surface of a substrate, such as the surface of an optical pin mold, to a desired surface finish and profile under the automated control of a computer during a polishing cycle. The polishing system includes a polishing spindle assembly that holds and rotates a polishing tool that is contacted under pressure with a surface of the mold pin. A torque sensor is associated with the polishing spindle assembly to sense a torque on the polishing tool during the polishing cycle. The polishing system further includes a feedback control system that dynamically adjusts the position of the polishing spindle assembly in response to the torque sensed by the torque sensor to maintain a substantially constant torque on the polishing tool during the polishing cycle.

Abstract: Self-aligned aperture masks are produced using a positive-acting photoresist (18) which is developed with a liquid developer. The apertures (30) of the mask have lower levels of inter-aperture variability than masks produced using mechanical transfer of toner particles (FIGS. 4-5 and 7-8), both for the apertures of a given mask and between masks.

Abstract: An optical lens cell, especially useful in projection televisions, includes a tubular optic support structure having an interior with a longitudinal central axis and a first optic support surface extending around the longitudinal central axis. The first optic support surface receives a first optic having an outer circumferential edge and a first mounting surface portion adjacent the circumferential edge. The mounting surface portion of the first optic extends transverse to the longitudinal central axis. A plurality of raised surface members are provided on the optic support surface. At least one resilient member extends transverse to the longitudinal central axis and is configured to contact the mounting surface portion of the first optic when the first optic is positioned adjacent the optic support surface.

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.

Abstract: An optical assembly (11) is formed by individually positioning a plurality of prisms (15) using mechanical reference surfaces (19) which are associated with the prism's diagonal (13) and are preferably formed by extensions of a first sub-prism (17A) beyond a second sub-prism (17B). The mechanical references surfaces and a first side of the prism engage fixed mechanical references (23) associated with a housing. A locking element (21) engages a second side of the prism and forces the mechanical reference surfaces and the first side of the prism against the fixed mechanical references to achieve accurate positioning of the prism's diagonal (13).

Abstract: A projection television lens cell and system including a tubular optic support structure having an interior with a longitudinal central axis. A first annular support surface extends around the longitudinal central axis for receiving a first optic having an outer circumferential edge. The first annular support surface includes at least a first resilient member configured to contact the outer circumferential edge of the first optic and to be moved in a radially outward direction by the first optic relative to the longitudinal central axis. The resilient member assists in preventing substantial movement of remaining portions of the tubular optic support structure, for example, during assembly and any heat induced thermal expansion of the optic in use.

Abstract: A lens assembly especially adapted for mounting in an environment subject to variable temperatures, such as a projection television set, including an automatic thermal focus adjustment. A lens mount is formed from a material having a first coefficient of thermal expansion and carries at least one lens. A focus mount is coupled to the lens mount and is formed from a material having a second coefficient of thermal expansion different from the first coefficient of thermal expansion. Adjustment and locking structure couples the lens mount to the focus mount and allows the lens mount to be axially adjusted relative to the focus mount and then locked in position. In use, the relative axial positions of the lens mount and focus mount automatically change to move the lens in response to a temperature change in the environment of use and after being locked in position with the adjustment and locking structure.

Abstract: A polarization conversion system provides generally uniform polarized illumination light while maximizing illumination brightness by utilizing all illumination light, particularly the typically brightest illumination light available in a central region. In one implementation, the polarization conversion system includes a pair of lens arrays that successively receive light from an illumination source. A planar array of polarization beamsplitters is positioned adjacent the latter lens array. Each polarization beamsplitter includes a pair of elongated right-angle prisms having their respective inclined faces positioned against each other and their lengths extending vertically across multiple lenslets of the latter lens array. The polarization beamsplitter array includes coplanar top and bottom array segments, the inclined faces of the prisms of the polarization beamsplitters of the top array segment being oriented at substantially one angle (e.g.

Abstract: Lenses for use with electronic imaging systems, e.g., systems employing CCDs, are provided. The lenses employ at least two lens elements, at least one of which is a dyed plastic lens element whose average percentage transmission for wavelengths between 400 nm and 550 nm is greater than its average percentage transmission for wavelengths between 550 nm and 700 nm. Through the use of such a dyed plastic lens element, the need for a separate spectral response flattening filter is eliminated thus reducing the cost, complexity, size, and weight of the electronic imaging system.

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: 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: 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 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.