Abstract: An optical system is described consisting of reflection birefringent light valves, polarizing beam splitter, color image combining prisms, illumination system, projection lens, filters for color and contrast control, and screen placed in a configuration offering advantages for a high resolution color display. In particular, the present invention includes a color splitting prism assembly having a plurality of output faces through which a separate color component is directed to be reflected by a respective light valve. Color absorbing filters are disposed at each of the output faces to absorb the color components not corresponding to the color directed through each output face.

Abstract: An optical system is described consisting of reflection birefringent light valves, polarizing beam splitter, color image combining prisms, illumination system, projection lens, filters for color and contrast control, and screen placed in a configuration offering advantages for a high resolution color display. The system includes a quarter wave plate positioned to suppress stray reflection from the projection lens. The system also includes a second quarter wave plate disposed on the screen and a polarizing film disposed on the second quarter wave plate to suppress ambient light from illuminating the screen and entering the system.

Abstract: An optical system is described consisting of reflection birefringent light valves, polarizing beam splitter, color image combining prisms, illumination system, projection lens, filters for color and contrast control, and screen placed in a configuration offering advantages for a high resolution color display. The illumination system includes a light tunnel having a cross-sectional shape corresponding to the geometrical shape of the spacial light modulator to optimize the amount of light projected onto the screen.

Abstract: In a light valve projection type image display device, a lighting device suitable for a device making use of polarization in particular is presented. A lighting device transformed in the direction of polarization comprising a light source, an elliptical mirror, polarized light selecting means positioned at a second focal point position of the elliptical mirror, collimating for transforming the light from the second focal point of the elliptical mirror into nearly parallel light while reflecting, polarization transforming provided in the collimating, and optical path transforming having an aperture in the central part is provided. The light is separated into first and second directions of polarization by the polarized light selecting. The light in the second direction of polarization is enters the collimating and the direction of polarization is transformed in the same direction as the light of the first direction of polarization.

Abstract: A display unit includes an optical modulation element for subjecting an incident light beam to optical modulation, and a coolant disposed in contact with an output side of the optical modulation element, wherein a focal distance of an output light beam of the optical modulation element is set to a predetermined distance in accordance with a length of the output light beam of the optical modulation element, which passes through the coolant.

Abstract: In a projection system for projecting a video picture composed of picture points on a screen with at least one light source which emits a light bundle and can be varied in intensity and with a deflecting device which deflects the light bundle to illuminate the picture points on the screen, a transformation optical system having at least two stages is arranged between the deflecting device and the screen and is corrected according to the tangent condition so as to be free of distortion. The transformation optical system has at least two optical stages. The first optical stage produces an intermediate image plane which is imaged on the screen by means of the subsequent optical stage (s).

Abstract: An optical system is described consisting of reflection birefringent light valves, polarizing beam splitter, color image combining prisms, illumination system having a light tunnel, projection lens, filters for color and contrast control, and screen placed in a configuration offering advantages for a high resolution color display.

Abstract: A beam combiner for an LCD projection television system makes use of a penta-prism which focuses three separate light sources on a viewing screen. The use of a penta-prism as a beam combiner allows for a compact light path, simplicity of manufacturing and a cost effective dichroic mirror arrangement as part of the penta prism. The light path within the penta-prism from the three light sources forms a right-angled triangle which provides the above-identified advantages.

Abstract: Projection apparatus comprising high resolution projection display systems that generate a relatively large high resolution image on a display screen, wherein seams and tiling artifacts in observation (image) space are eliminated or minimized. The projection apparatus comprises an image source that includes a plurality of small tiled image displays, relay optics, and a photoactivated reflective liquid crystal light valve. The small tiled or mosaic-like displays that provide source images that are displayed. The images projected by the image displays are imaged onto the light valve. A polarizing beamsplitter is disposed adjacent an output surface of the light valve, and an illumination source provides illumination light that is projected by way of the polarizing beamsplitter onto an output surface of the light valve. The illumination light is reflected from the output surface of the light valve back through the polarizing beamsplitter. A projection lens projects the illumination light onto the display screen.

Abstract: In a projector comprising three image forming devices, disposed between a separation optical section and a combination optical section, for processing a red, a green, and a blue light beams, at least one of the three image forming devices comprises a polarization direction converting means, such as a halfwave plate for converting polarization direction for one of the red, the green, and the blue image light beams so that one of a color combining dichroic mirrors has a cutoff wavelength of spectral characteristic which shifts toward outside for one of the red, the green, and the blue central wavelengths from that of one of a color separating dichroic mirrors. The halfwave plate may be disposed in a light-leaving side of at least one of the three image forming devices.

Abstract: An image projection system employing microlaser and/or diode laser arrays. Each laser in each array is individually addressable. The system includes three linear laser arrays, one red, one green, and one blue, each individually addressable laser being powered and modulated in accordance with the input image signal. When microlaser arrays, which are energized by laser diode pumps, are used, the laser diode pumps are formed in equivalent arrays. The laser output beams are combined in a dichroic prism and reflected off a rotating multifaceted scanning mirror which effects two dimensional scanning as it rotates. The image beam reflected from the scanner passes through an imaging lens, a speckle eliminator and then onto the projection screen. The invention also includes the method of generating and scanning the image beam, as well as the novel speckle eliminator and the microlaser array configured for optimally close spacing to achieve the desired result.

Abstract: Color separation dichroic mirrors (40,42) positioned between a group of reflective liquid crystal light valves (26,28,30) and a polarization analyzer (14) enable a single projection lens (18) to project all colors via a light beam of single linear polarization with a high degree of contrast, efficiency and color separation. The polarization analyzer (14) directs a light beam with a single polarization state to a pair of dichroic color filters (40,42) which separate the beam into three different colors that are sent to three different reflective liquid crystal light valves (26,28,30). The light valves reflect the respective colored light beams with change of polarization state back to the dichroic mirrors (40,42) which combine the three colors into a single combined multi-color beam that is fed through the polarization analyzer (14) to a single system projection lens (18).

Abstract: An optical projector arrangement includes a light source. Light from the light source is formed into a collimated beam travelling along an axis by optics. The light is split into red, green and blue components travelling in different paths by a splitter. The components are subsequently recombined by a synthesizer to continue along the axis to a projection lens. A respective liquid crystal modulator is included in each different path. In order to increase the optical length of the path taken by the green component so that it is equal to the lengths of the paths taken by the red and blue components, a path length compensator is included in the path for the green component, which path would otherwise be along the axis for the whole of its length.

Abstract: An image projector apparatus for producing an image for display on a projection screen. The image projector apparatus includes a plurality of first microlenses each receiving light from a light source, a liquid crystal display having a plurality of pixels each adapted to receive light from a respective one of the first microlenses and provide respective image light therefrom in response to image information supplied thereto, a plurality of second microlenses each receiving the image light from a respective one of the pixels and projecting parallel image light therefrom, and a projection lens receiving the parallel image light from each of the second microlenses and projecting the same onto the projection screen. The projection lens may be moved or positioned such that an optical center axis thereof is offset from an image center axis of the liquid crystal display so as to eliminate or minimize a so-called keystone distortion.

Abstract: A liquid crystal projector which splits white light projected from a light source and light-intensity-modulates and synthesizes the split light components to project the synthesized light components onto a screen. The projector includes a dichroic mirror having a light transmittance characteristic in which two color light components of the three color light components being adjacent in spectrum are transmitted, and a dichroic mirror having a light transmittance characteristic in which the remaining color light excluding the two color light components is reflected. The location of the light source is appropriately modified inside the projector. Accordingly, the production cost is reduced, the heat produced by the light source is not exhausted toward the viewers and the projector is miniaturized.

Abstract: In a color image display apparatus, light beams intensity modulated by a green color image signal are deflected by an ocillating mirror, and then focused on a photo-conductive layer (PCL) member of a light-written type spacial light modulation element (SLM) through two focusing lenses for light write operation. Light beams intensity modulated by a time-axis compressed time-divisional image signal of two remaining colors (red and blue) are deflected by another mirror oscillated simultaneously with the ocillating mirror, and then focused on a PCL member of a SLM of the same type through two focusing lenses for light write operation. A read light beam is resolved into the light of the green wave length band and the lights of red and blue wave length bands, respectively, and then given to the SLMs, respectively for light read operation. The two read light beams reflected by the SLMs are synthesizing, and then projected on a screen through a common projection lens.

Abstract: A projector is provided with three CRTs, a mirror system, and a projection lens. The three CRTs radiating light beams of colors different from one another are arranged such that respective tube axes thereof exist on the same plane. The mirror system includes dichroic mirrors for reflecting the light beams of the respective colors from the CRTs in a direction perpendicular to the above plane. The mirror system is arranged at front sides of the CRTs. The projection lens is arranged on an optical path of the reflected light beam from the mirror system so as to combine the reflected light beams of the respective colors and to project the combined light beam onto the screen. The thus constructed projector has a short depth since the light beams from the respective CRTs are projected in the direction perpendicular to the above plane by the dichroic mirrors of the mirror system.

Abstract: A projection type display device comprising a condensing lens and a total reflection mirror disposed downstream of a single light source, a pair of crossing dichroic mirrors disposed along the path of the light reflected from the total reflection mirror and adapted to achieve both the color separation and the color combination, image displays disposed respective paths of separated R, G and B color beams, and field lenses each disposed between each of the image display and the corresponding dichroic mirror and adapted to reverse the paths of R, g and B color beams. The beam combined by the dichroic mirrors and carrying R, G and B color images is transmitted through a central aperture of the total reflection mirror to a projection lens and then enlarged at the projection lens to be projected onto a screen. The display device is capable of achieving both the color separation and the color combination by using inexpensive dichroic mirrors in place of expensive dichroic prism and color filters.

Abstract: A projection TV light controller is comprised of a plurality of blocks of material which are transparent to the light of a lamp, adjacent sides of the blocks being cooperatively shaped and being disposed adjacent to each other, to form a single light controlling element. The element is shaped to surround a cylindrical region coaxial with a central axis of the element for containing the lamp. Light is conducted from the lamp in each of the three primary colours into respective ones of the blocks. Apparatus is associated with each block for creating video display light signals relating to a corresponding primary colour. The video display light signals of all of the primary colours are combined into a single light beam which is conducted out of the light controlling element. With the lamp being contained in a central region, it can be cooled either by convection, by a fan, or by a fused quartz fluid jacket around the lamp, maintaining the block cool and minimally subject to expansion or contraction.

Abstract: A high-efficiency optical system for use in a liquid-crystal light-valve video projector. High intensity, unpolarized white light is separated into primary color components by color-selective filters transmitting light containing both first and second polarization states. Light of each primary color is characterized by a wavelength passband whereby the endpoints of the passband are defined by first and second wavelengths. The second passband endpoint of the first polarization state of the first primary color overlaps the first passband endpoint of the second polarization state of the second primary color, and the second passband endpoint of the second polarization state of the second primary color overlaps the first passband endpoint of the first polarization state of the third primary color. In addition, the video projector design utilizes low f/# optics in conjunction with absorptive polarizers to remove residual light of an unwanted polarization state allowed into the system by the low f/# optics.

Abstract: A high-efficiency optical system for use in a liquid-crystal light-valve video projector. High intensity, unpolarized white light is separated into primary color components by color-selective filters transmitting light containing both first and second polarization states. Light of each primary color is characterized by a wavelength passband whereby the endpoints of the passband are defined by first and second wavelengths. The second passband endpoint of the first polarization state of the first primary color overlaps the first passband endpoint of the second polarization state of the second primary color, and the second passband endpoint of the second polarization state of the second primary color overlaps the first passband endpoint of the first polarization state of the third primary color. In addition, the video projector design utilizes low f/# optics in conjunction with absorptive polarizers to remove residual light of an unwanted polarization state allowed into the system by the low f/# optics.

Abstract: This specification discloses an image projector for projecting a tri-color composite optical image on a screen as a magnified optical image. A reading light beam emitted from a light source is separated into three color beams, e.g., Red, Green and Blue color beams through a tri-color separation and composition optical system. The separated color beams are irradiated on image forming devices provided correspondingly with Red, Green and Blue color images to read out color images respectively therefrom. Each of the reflected light beams from the image forming device carrying color image information impinges again on the tri-color separation and composition optical system to compose a composite image beam. The composite image beam is projected on the screen through an optical lens system comprising a first lens group, a second lens group and a third lens group disposed along an optical axis in order.

Abstract: A three color separation/synthesis mirror device includes a housing, four dichroic mirrors which are arranged in the housing and cross with each other at right angles to form an X-shape, and a liquid filled in the housing so as to submerge the respective dichroic mirrors. A refractive index of the liquid is higher than that of the dichroic mirrors. A correction prism for making an emergent light in parallel to an incidental light may be located in a corner on the incidental side of the X-shaped dichroic mirrors. Double image blurs due to the entrance rays can be obviated. Also, such a characteristic that the refractive index of the liquid is lowered when the liquid is heated, is utilized so that the refractive index of the liquid becomes close to the refractive index of the glass.

Abstract: A front projection video display system achieves high contrast without darkened ambient room conditions by a specific combination and arrangement of the components of this system. These components include a front-projection video projector which projects an image of particular direction of polarization; polarizing lenses which polarize light radiated from room light fixtures in a direction orthogonal to that of the projected image; a polarizing filter which substantially transmits light polarized parallel to the projected image and substantially blocks light orthogonal to the projected image; and a projection screen which is polarization maintaining and which receives the projected image for viewing by the viewing audience.

Abstract: An image projection apparatus such as a video projector or projection television is provided for decreasing light loss. The apparatus has three cathode ray tubes for respectively providing images of red, green and blue, two dichroic mirrors for combining the images onto the same axis, and a lens group for enlarging and projecting the combined image toward a screen, wherein the inclination of each dichroic mirror is adjusted such that the incident angle of light incoming from the cathode ray tube to the dichroic mirror is less than 45.degree.. Thus, the degree of stop-band shift due to refractive index variations of an incidence medium is decreased. Also, the reflectance for incoming light having a wavelength coincident with the stop band is increased.