Abstract: A polarization conversion system (PCS) is located in the output light path of a projector. The PCS may include a polarizing beam splitter, a polarization rotating element, a reflecting element, and a polarization switch. Typically, a projector outputs randomly-polarized light. This light is input to the PCS, in which the PCS separates p-polarized light and s-polarized light at the polarizing beam splitter. P-polarized light is directed toward the polarization switch on a first path. The s-polarized light is passed on a second path through the polarization rotating element (e.g., a half-wave plate), thereby transforming it to p-polarized light. A reflecting element directs the transformed polarized light (now p-polarized) along the second path toward the polarization switch. The first and second light paths are ultimately directed toward a projection screen to collectively form a brighter screen image in cinematic applications utilizing polarized light for three-dimensional viewing.

Abstract: Chemically-bonded retarder stacks are provided in this disclosure. A first organic layer having a first molecular orientation is chemically welded to a second organic layer having a second molecular orientation. The first and second molecular orientations are crossed when the organic layers are laminated. The first and second organic layers may be polycarbonate films, which can be welded together using a suitable solvent.

Abstract: Disclosed herein are light collectors for use in projection applications. The light collectors gather light from surface emitting sources (e.g., LEDs) of differing color (or same color in some embodiments) using input lightpipes. A light collection system splits the light into orthogonal linear polarization states and efficiently propagates the light by use of a polarizing beamsplitter (PBS) and a reflecting element. Further, the light collection system may efficiently homogenize the light using an output lightpipe in a lightpath from the output of the PBS and the reflecting element. In addition, the light collection system may present a single, linear polarization at the output through the use of a half-wave switch (LC cell) in some embodiments or ColorSelect filter in other embodiments. The light collection system may be integrated into a single, monolithic glass, plastic or combination glass/plastic assembly.

Abstract: Described are various compensators for compensating for in-plate and out-of-plane retardances of LC panels in their dark states.

Abstract: A simple reflecting layered structure is disclosed that is attached to, or incorporated into, an automobile windshield that allows a head-up-display (HUD) to be viewed through anti-glare, p-polarized sunglasses without double imaging and without substantial net alteration of the polarization state of light. The invention relies on the negligible reflection of p-polarized light at material interfaces oriented at the typical angles within an automobile HUD system. The reflecting structure consists of two polarization manipulating films sandwiching a s-polarized reflector. A suitable reflector could constitute the natural reflection off interfaces between the two films and a single medium of substantially different refractive index. One embodiment utilizes two stretched polymer half wave retardation films separated with an air gap. The optic axes of the films are essentially crossed oriented at approximately 45° to both s- and p-polarization axes.

Abstract: Described are various compensators for compensating for in-plate and out-of-plane retardances of LC panels in their dark states.

Abstract: Disclosed herein are light collectors for use in projection applications. The light collectors gather light from surface emitting sources (e.g., LEDs) of differing color (or same color in some embodiments) using input lightpipes. A light collection system splits the light into orthogonal linear polarization states and efficiently propagates the light by using polarizing beamsplitters (PBSs) and a reflecting element to recycle light at a port of the PBS. Further, the light collection system may efficiently homogenize the light using an output lightpipe in a lightpath from the outputs of the PBSs. In addition, the light collection system may present a single, linear polarization at the output through the use of a half-wave switch (LC cell) in some embodiments or ColorSelect filter in other embodiments. The light collection system may be integrated into a single, monolithic glass, plastic or combination glass/plastic assembly.

Abstract: Disclosed herein are light collectors for use in projection applications. The light collectors gather light from surface emitting sources (e.g., LEDs) of differing color (or same color in some embodiments) using input lightpipes. A light collection system splits the light into orthogonal linear polarization states and efficiently propagates the light by use of a polarizing beamsplitter (PBS) and a reflecting element to recycle light at a port of the PBS. Further, the light collection system may efficiently homogenize the light using an output lightpipe in a lightpath from the output of the PBS. In addition, the light collection system may present a single, linear polarization at the output through the use of a half-wave switch (LC cell) in some embodiments or ColorSelect filter in other embodiments. The light collection system may be integrated into a single, monolithic glass, plastic or combination glass/plastic assembly.

Abstract: A sequential color system with reduced or eliminated global temporal notching losses may be implemented with a buffered display panel. Fast global blanking and/or inter-field images may be used to reduce or eliminate the global temporal notching losses. When consecutive states of a pixel are “on,” an inter-field image may be displayed by maintaining the pixel in an “on” state instead of turning the pixel “off” and then turning the pixel “on.” This improves the color brightness and saturation. The display may be implemented with a color wheel or with a color switch.

Abstract: An LCoS projection system provides a form birefringent polarization beam splitter (PBS) having an output modulator port, a light modulating panel, and a biaxial compensation element between the output modulator port and the light modulating panel. In one embodiment, the biaxial compensation element is a biaxial quarter wave plate. In another embodiment, the biaxial compensation element includes a uniaxial quarter wave plate and a biaxial trim retarder. The biaxial compensation element provides improved contrast performance.

Abstract: A direct view display provides a light modulating panel and a backlight including first and second sets of spectral emitters. The first set of spectral emitters generate a first light bundle and the second set of spectral emitters generate a second light bundle. Several modes of operation may be provided including (1) an advanced 2D mode, (2) an enhanced color gamut mode employing simultaneous illumination of the first and second set of spectral emitters, (3) a privacy screen mode, (4) a channel multiplexed mode, and (5) a stereoscopic image mode. The latter three modes utilize the first and second set of spectral emitters to alternately illuminate a portion of the light modulating panel. Images and representations generated by the direct view display operating in the latter three modes are viewed using appropriate eyewear having filters with passband characteristics to transmit the respective light bundle.

Abstract: Provided are several apparatus and methods to attenuate illumination light in a projector. Illumination light may be attenuated by directing polarized light toward a liquid crystal (LC) attenuation panel. The panel selectively modulates some, all, or none of the polarized light passing through. The light from the panel is then directed toward a polarization device. The polarization device analyzes the polarized light, and allows or denies the light to pass therethrough based on the polarization of the light.

Abstract: A polarization beam splitter (PBS) and combiner includes a multilayer birefringent stack adjacent to a dichroic coating, sandwiched between glass prisms. This configuration overcomes the reflected wave distortion associated with a conventional multilayer birefringent cube PBS while maintaining excellent polarization performance. An exemplary application of the PBS and combiner is in a four-port LCOS imaging system. LCOS projection architectures based on the PBS are also disclosed.

Abstract: The present application describes a retarder stack color switch using a single polarization analyzer for reflective-mode projection displays. The single polarization analyzer permits additive mode switching, which optimizes the chrominance of the additive primary outputs and the black state. Moreover, the single analyzer color switch provides a white state, which is frequently used in sequential systems. The single analyzer color switch overcomes some of the cost and manufacturing challenges associated with conventional transmissive full color switches based on retarder-stack-filters. The single analyzer color switch according to an embodiment uses a split-path so that relatively weak colors can follow a “high-efficiency” path.

Abstract: Disclosed are digitally-switchable bandpass filters combining non-tunable retarder stacks with switchable liquid crystal cells. The disclosed filter embodiments function like a filter wheel with no moving parts that may provide faster switching, better image registration, compact size, and lower electrical power consumption. These benefits are attractive in portable handheld devices, such as bio-hazard sensors or glucose monitors.

Abstract: An achromatic polarization switch (APS) acts on linear polarized light to provide orthogonal polarized output states over a range of visible wavelengths. In a first switching state, the APS is operable to pass light of a first polarization state therethrough. In a second switching state, the APS is operable to transform light passing therethrough to a substantially orthogonal second polarization state. Used in conjunction with orthogonal analyzing eyewear, left and right eye images are time-sequentially modulated in orthogonal polarization states by the APS to yield a stereoscopic 3D image sensation.

Abstract: Described are illumination systems for providing visible images. The systems include a first image projection sub-system operable to provide a first stereo-image output formed by light having a first polarization; a second image projection sub-system operable to provide a second stereo-image output formed by light having a second polarization; a projection means wherein the projection means projects the first and second stereo-image outputs onto a display through a common lens; wherein the system is operable to provide orthogonal first polarization and second polarization. Typically, the first and second image outputs are formed from light having orthogonal polarizations and the system is preferably switchable between providing orthogonal and non-orthogonal first and second images. In preferred embodiments the system is operable to provide nonstereo images while providing increased resolution. Preferred systems include a common light source and a common projection lens.

Abstract: A birefringent network can be formed from a pair of beam directing elements that sandwich a birefringent filter. One of the beam director elements can be a polarizing beam splitter and the other of the beam director elements can be a reflector or polarizing beam splitter. The polarizing beam splitters can be formed by an anisotropic material sandwiched between two isotropic pieces and can include optical films to couple both polarizations of light into and out of the beam splitters. The polarizing beam splitters also can be formed by anisotropic material on either side of an isotropic bow-tie piece, all of which is sandwiched a pair of isotropic pieces. A birefringent network also can be formed by a pair of bulk birefringent beam splitters sandwiching a birefringent filter. Little or no polarization mode dispersion occurs in these birefringent networks since all of the beams travel the same distances through the same elements.

Abstract: Described are tilted compensators for compensating for in-plate and out-of-plane retardances of LC panels in their dark states, including a single tilted biaxial retarder or compound retarder comprising more than one biaxial film, which are effective to compensate both for nonideal polarization effects of LC panels and other optical components in optical projection systems. Also described are tilted compensators for deflecting away from a projection system optical path unwanted reflected light.

Abstract: The selective filtering of light by polarization interference may be used to enhance vision and/or protect eyes from harmful light rays. For example, such filtering may be used in sunglasses, color corrective eyewear or protective eyewear. The selective filtering of incident light may provide any desired spectral transmission (including visible light and light not visible to the eye) and is performed by a pair of polarizing elements that sandwich a retarder stack. The filtering structure may be formed by multi-layer polarizing structures and may be formed by fabricating sheet laminates that are die cut to form inexpensive laminates. The laminates may be flat or curved in one (e.g., wrap-around) or more dimensions.