Abstract: In a light projection system, potentially hierarchical levels of light intensity control ensure proper laser-light output intensity, color channel intensity, white point, left/right image intensity balancing, or combinations thereof. The light projection system can include a light intensity sensor in an image path, in a light-source subsystem light-dump path, in a light-modulation subsystem light-dump path, in a position to measure light leaked from optical components, or combinations thereof.

Abstract: In a light projection system, potentially hierarchical levels of light intensity control ensure proper laser-light output intensity, color channel intensity, white point, left/right image intensity balancing, or combinations thereof. The light projection system can include a light intensity sensor in an image path, in a light-source subsystem light-dump path, in a light-modulation subsystem light-dump path, in a position to measure light leaked from optical components, or combinations thereof.

Abstract: Etendue maintaining polarization switching occurs, according to various embodiments, with a mirror that quickly transitions between two positions. Light having uniform polarization is transmitted to the mirror. Light reflected off of the mirror in one of the two positions has its polarization changed, whereas light reflected off of the mirror in the other of the two positions has its polarization maintained. Thereafter, the polarization-changed light and the polarization-maintained light easily may be recombined in an entendue-maintaining manner. Because the recombined light includes two different polarization states, stereoscopic images may be generated.

Abstract: A beam alignment chamber extending in a length direction comprising a base having a front edge, and two side edges, first and second opposed side walls connected to the base, and extending along the length of the base, a front wall located at the front edge of the base having an output opening. The beam alignment chamber further comprises a plurality of arrays of light sources disposed to direct light beams through the first or second side walls, and a plurality of reflectors mounted on the base, each having independent yaw and pitch adjustments, each reflector being paired with a corresponding array of light sources, the base-mounted reflectors being disposed to direct the light beams along the length of the beam alignment chamber through the output opening forming an aligned two-dimensional array of parallel light beams.

Abstract: A projection display surface for reducing speckle artifacts from a projector having at least one narrow band light source having an incident visible wavelength band, wherein the incident visible wavelength band has an incident peak wavelength and an incident bandwidth, comprising: a substrate having a reflective layer that reflects incident light over at least the incident visible wavelength band; and a fluorescent agent distributed over the reflective layer, wherein the fluorescent agent absorbs a fraction of the light in the incident visible wavelength band and emits light in an emissive visible wavelength band having an emissive peak wavelength and an emissive bandwidth; wherein return light from the projection display surface produced when incident light in the incident visible wavelength band is incident on the projection display surface contains light in both the incident visible wavelength band and emissive visible wavelength band, thereby reducing speckle artifacts.

Abstract: A projection display surface for reducing speckle artifacts from a projector having at least one narrow band light source having an incident visible wavelength band, wherein the incident visible wavelength band has an incident peak wavelength and an incident bandwidth, comprising: a substrate having a reflective layer that reflects incident light over at least the incident visible wavelength band; and a fluorescent agent distributed over the reflective layer, wherein the fluorescent agent absorbs a fraction of the light in the incident visible wavelength band and emits light in an emissive visible wavelength band having an emissive peak wavelength and an emissive bandwidth; wherein return light from the projection display surface produced when incident light in the incident visible wavelength band is incident on the projection display surface contains light in both the incident visible wavelength band and emissive visible wavelength band, thereby reducing speckle artifacts.

Abstract: A projection display surface for reducing speckle artifacts from a projector having at least one narrow band light source having an incident visible wavelength band, wherein the incident visible wavelength band has an incident peak wavelength and an incident bandwidth, comprising: a substrate having a reflective layer that reflects incident light over at least the incident visible wavelength band; and a fluorescent agent distributed over the reflective layer, wherein the fluorescent agent absorbs a fraction of the light in the incident visible wavelength band and emits light in an emissive visible wavelength band having an emissive peak wavelength and an emissive bandwidth; wherein return light from the projection display surface produced when incident light in the incident visible wavelength band is incident on the projection display surface contains light in both the incident visible wavelength band and emissive visible wavelength band, thereby reducing speckle artifacts.

Abstract: A projection apparatus for producing color images having reduced speckle artifacts comprising: at least three narrow band light sources having first, second and third visible wavelength bands; a digital image source providing color digital image data; at least one spatial light modulator for forming a color image using light responsive to the color digital image data; a projection display surface including a reflective layer that reflects incident illumination in the first, second, and third wavelength bands; and a fluorescent agent that absorbs a fraction of the incident light in the first visible wavelength bands and emits light in a corresponding first emissive visible wavelength band; and a projection lens that projects the color image onto the projection display surface; wherein return light from the projection display surface contains light in both the first incident visible wavelength band and the first emissive visible wavelength band, thereby reducing speckle artifacts.

Abstract: An imaging lens having reduced susceptibility to thermally-induced stress birefringence for imaging an object plane to an image plane; comprising: an aperture stop positioned between the object plane and the image plane; a first group of lens elements located on the object plane side of the aperture stop; and a second group of lens elements located on the image plane side of the aperture stop; wherein the lens elements immediately adjacent to the aperture stop are fabricated using glasses having a negligible susceptibility to thermal stress birefringence as characterized by a thermal stress birefringence metric; and wherein the other lens elements in the first or second groups of lens elements are fabricated using glasses having at most a moderate susceptibility to thermal stress birefringence as characterized by the thermal stress birefringence metric.

Abstract: A stereoscopic digital image projecting system has a light source system providing polarized illumination having a first polarization state and a beam splitting system with a rotating segmented disk in the illumination, alternately generating first and second light beams, the rotating segmented disk having outer segments alternately transmissive and non-transmissive and inner segments radially aligned with the outer segments and alternately reflective and transmissive. A polarization rotator in a path of either the first or second light beam rotates the first polarization state to a second state orthogonal to the first. A combining system combines the first and second light beams into a combined light beam. A spatial light modulator modulates the combined light beam in a manner consistent with stereoscopic image data to form first and second modulated images having substantially orthogonal polarization states. Projection optics project the modulated images onto a display surface.

Abstract: A beam alignment chamber comprising: a base, first and second side walls connected to the base, and a front wall located at the front edge of the base having an output opening. The beam alignment chamber further including a plurality of light sources disposed to direct light beams through the first or second side walls, a plurality of reflectors mounted on the base, each having independent yaw and pitch adjustments, each being disposed to direct the light beams from a corresponding light sources along the length of the beam alignment chamber through the output opening forming an aligned array of parallel light beams, and one or more optical elements positioned in the optical path of the aligned array of light beams disposed to correct the beam divergence with respect to at least one axis.

Abstract: A method for designing an imaging lens having reduced susceptibility to thermally-induced stress birefringence, the imaging lens having first and second groups of lens elements located either side of an aperture stop, the method comprising: defining a set of lens design attributes; defining a set of lens performance criteria including a thermally-induced stress birefringence performance criterion; defining a first set of candidate glasses having a negligible susceptibility to thermal stress birefringence and a second set of candidate glasses having at most a moderate susceptibility to thermal stress birefringence; selecting glasses for lens elements that are located adjacent to the aperture stop from the first set of candidate glasses; selecting glasses for the remaining lens elements from the first or second sets of candidate glasses; and using a computer processor to determine a lens design for the imaging lens.

Abstract: An imaging system having reduced susceptibility to thermally induced stress birefringence, comprising; a relay lens, which images the object plane onto an intermediate image plane; a projection lens, which images the intermediate image plane onto the display surface. The lens elements that are immediately adjacent to a relay lens aperture stop and a projection lens aperture stop are fabricated using glasses having a negligible susceptibility to thermal stress birefringence, and the other lens elements are fabricated using glasses having at most a moderate susceptibility to thermal stress birefringence as characterized by the thermal stress birefringence metric.

Abstract: Etendue maintaining polarization switching occurs, according to various embodiments, with a mirror that quickly transitions between two positions. Light having uniform polarization is transmitted to the mirror. Light reflected off of the mirror in one of the two positions has its polarization changed, whereas light reflected off of the mirror in the other of the two positions has its polarization maintained. Thereafter, the polarization-changed light and the polarization-maintained light easily may be recombined in an entendue-maintaining manner. Because the recombined light includes two different polarization states, stereoscopic images may be generated.

Abstract: A digital projection apparatus for projecting digital image data comprising: one or more image forming assemblies; a display surface; and projection optics for projecting an image of the spatial light modulators in the one or more image forming assemblies onto the display surface.

Abstract: A beam alignment system for generating an aligned two-dimensional array of parallel light beams, comprising a beam alignment chamber including a base extending in a length direction and a plurality of reflectors mounted on the base, each having independent yaw and pitch adjustments. The beam alignment system further includes a plurality of arrays of light sources, each generating an array of light beams and being paired with a corresponding reflector, the reflectors being disposed to direct the light beams along the length of the beam alignment chamber forming an aligned two-dimensional array of parallel light beams.

Abstract: Etendue maintaining polarization switching occurs, according to various embodiments, with a mirror that quickly transitions between two positions. Light having uniform polarization is transmitted to the mirror. Light reflected off of the mirror in one of the two positions has its polarization changed, whereas light reflected off of the mirror in the other of the two positions has its polarization maintained. Thereafter, the polarization-changed light and the polarization-maintained light easily may be recombined in an entendue-maintaining manner. Because the recombined light includes two different polarization states, stereoscopic images may be generated.

Abstract: A projection apparatus has a spatial light modulator to modulate illumination from a laser light source. A base projection lens has, from its long conjugate side to its short conjugate side, a first lens group with negative focal length and with a first lens element that has a negative focal length and a second lens element of positive focal length, a second lens group of negative focal length and spaced apart from the first lens group and having one or more cemented lens elements, and a third lens group spaced apart from the second lens group and having a lens with a positive focal length. The base projection lens has a first field of view and is telecentric in its short conjugate. An afocal attachment to the base projection lens alters the first field of view by the same amount in both of two orthogonal directions.

Abstract: A digital image projector includes a light assembly configured to project light along a light path from at least one laser array light source, the projected light having an overlapping far field illumination in a far field illumination portion of the light path; a temporally varying optical phase shifting device configured to be in the light path; an optical integrator configured to be in the light path; a spatial light modulator located downstream of the temporally varying optical phase shifting device and the optical integrator in the light path, the spatial light modulator configured to be located in the far field illumination portion of the light path; and projection optics located downstream of the spatial light modulator in the light path, the projection optics configured to direct substantially speckle free light from the spatial light modulator toward a display surface.

Abstract: A beam combiner for combining a plurality of light beams onto an optical path, comprising: a first dichroic element having a dichroic coating that is disposed to transmit light of a first wavelength band along the optical path and to reflect light of a second wavelength band onto the optical path, and a second dichroic element having a dichroic coating that is disposed to transmit the light of the first and second wavelength bands along the optical path and to reflect light of a third wavelength band onto the optical path. The beam combiner further includes a phase difference compensation multilayer thin-film stack that provides at least one reflectance edge transition that lies outside any of the first, second, and third wavelength bands and which provides compensation for an accumulated phase difference for polarization states of the transiting in at least one of the first, second, and third wavelength bands.