Abstract: In a projection type video display apparatus, in order to assure sufficient brightness by suppressing a decrease in light utilization efficiency inside a limited output aperture area of a light source unit, a transmission or reflection type liquid crystal is used for a video display device and the light source unit having a plurality of reflectors or focusing mirrors in correspondence with LED's representing light sources is so constructed as to satisfy D<4×f or D<4×Z, where D represents an effective diameter of a reflector, f represents a focal distance of a mirror and Z represents a distance between a light emitter of the light source and an apex at a center of the mirror.

Abstract: A technique is provided that improves the usage ratio of light in the illumination optical system of an image display apparatus, in which the cross-sectional size or shape of the flux of light that has formed a light source image of an LED-based light-emitting section is converted by anamorphic optics, such as collimator lens, into a size or shape appropriate for an aperture in the portion that permits the flux of the light source image to pass through, in an optical system leading to an image display element(s), and thus the quantity of fluxes of light passed through the aperture is increased.

Abstract: The image display device is configured to include the light source including a plurality of semiconductor light-emitting elements, a parallelizing unit including a plurality of cell lenses arranged in a one-to-one correspondence with each of the plurality of semiconductor light-emitting elements, an image display element for forming an optical image, a pair of lens-array groups located between the parallelizing unit and the image display element, and a projection unit for enlarging and projecting the optical image formed on the image display element. Moreover, the plurality of semiconductor light-emitting elements are located at substantially focal points of the cell lenses of the parallelizing unit.

Abstract: An object of the invention is to achieve a high intensity, a compact structure, a cost reduction and a heat radiation of a liquid crystal panel, in a projection type video display apparatus employing a combination of LED light sources and a light pipe. The light pipe is formed in a hollow type so as to be utilized as a cooling wind path. Further, a permeable or reflective baffle plate is provided within the light pipe. Further, the light pipe is formed by coating a mirror on an inner surface of an optical case integrally formed by fixing optical parts. Further, a dichroic mirror is arranged in an LED light source outgoing surface.

Abstract: If a projection display device includes a shifting mechanism for shifting a projection lens to adjust the direction in which the display projects an optical image, it is difficult to find suitable position where the display should be installed. Thus, the projection lens is fitted with a projection angle adjusting mechanism, which includes an adjusting dial having a scale representing the position of the lens relative to a display element. The projection display device is capable of automatically displaying on the projected optical image a scale image corresponding to the scale. The projection display also is capable of displaying on the projected optical image the position of the optical axis of the projection lens, which can be shifted by the adjusting mechanism.

Abstract: A liquid crystal projector comprises an illuminating optical system including a light source, a color separating optical system for separating illuminating light rays emitted by the illuminating optical system into light rays of three colors, a projection lens unit comprising a projection lens, a cross dichroic prism disposed near a light receiving end of the projection lens, and a plurality of liquid crystal panels arranged around the cross dichroic prism, and a light source power supply for supplying power to the light source. The projection lens unit, the color separating optical system, the illuminating optical system and the light source power supply are arranged in that order. The liquid crystal projector has an outside size in a horizontal plane of 263 mm by 318 mm or below. The liquid crystal panels have a display screen size of 0.9 in. A cooling fan for cooling the plurality of liquid crystal panels is disposed beside the projection lens.

Abstract: An image display technique which projects R, G, and B light rays on a display device to form an image with an increased utilization ratio of light and an increased screen brightness. R, G, and B light rays as a result of color separation are reflected by plural reflective surfaces on the inner side, etc. of a rotary polyhedral reflector, so that, as the reflector rotates around a central axis and its reflection plane sequentially changes from one reflective surface to a next one, the reflected light rays are projected on a display device surface in different positions and scroll in a prescribed direction.

Abstract: The image display device is configured to include the light source including a plurality of semiconductor light-emitting elements, a parallelizing unit including a plurality of cell lenses arranged in a one-to-one correspondence with each of the plurality of semiconductor light-emitting elements, an image display element for forming an optical image, a pair of lens-array groups located between the parallelizing unit and the image display element, and a projection unit for enlarging and projecting the optical image formed on the image display element. Moreover, the plurality of semiconductor light-emitting elements are located at substantially focal points of the cell lenses of the parallelizing unit.

Abstract: A bright image with smooth grayscale is ensured. Semiconductor light emitting devices that separately emit red, green, and blue light are used as a light source. The peak values of power needed to cause the semiconductor light emitting devices to emit light are varied according to image grayscale during the period of one cycle of screen display.

Abstract: A technique is provided that improves the usage ratio of light in the illumination optical system of an image display apparatus. The cross-sectional size or shape of the flux of light that has formed a light source image of an LED-based light-emitting section is converted by anamorphic optics, such as collimator lens, into a size or shape appropriate for an aperture in the portion that permits the flux of the light source image to pass through, in an optical system leading to an image display element(s), and thus the quantity of fluxes of light passed through the aperture is increased.

Abstract: An LED technology is adapted to a video display in order to ensure high image quality. A semiconductor light-emitting device having a flip-chip structure is adopted as a light source. Polarized light of white light or of each of red, green, and blue light waves, of which one polarized light component is converted to become consistent with the other component, is radiated from the light source. In the semiconductor light-emitting device, a light transmissive substrate or a quarter-wave phase difference plate that turns the direction of polarization, and a reflective sheet polarizer that reflects one of P-polarized light and S-polarized light and transmits the other polarized light are disposed on the light-emitting side of an LED chip light emitter formed on a reflecting electrode.

Abstract: By making the beam polarization state in a cross prism having a dichroic function for an incident beam on a reflection type liquid crystal panel the same as that for a reflected ON beam, a small-sized, low cost projection type projector apparatus is provided. A Faraday rotator having a Faraday rotation angle of 45 degrees is disposed on an optical path between a PBS and a cross prism. A half-wave plate having such a polarization axis as to rotate a polarization angle of linearly polarized light by 45 or 135 degrees is disposed on an optical immediately before or behind the Faraday rotator.

Abstract: In a projection type video display apparatus, in order to assure sufficient brightness by suppressing a decrease in light utilization efficiency inside a limited output aperture area of a light source unit, a transmission or reflection type liquid crystal is used for a video display device and the light source unit having a plurality of reflectors or focusing mirrors in correspondence with LED's representing light sources is so constructed as to satisfy D<4×f or D<4×Z, where D represents an effective diameter of a reflector, f represents a focal distance of a mirror and Z represents a distance between a light emitter of the light source and an apex at a center of the mirror.

Abstract: An object of the invention is to achieve a high intensity, a compact structure, a cost reduction and a heat radiation of a liquid crystal panel, in a projection type video display apparatus employing a combination of LED light sources and a light pipe. The light pipe is formed in a hollow type so as to be utilized as a cooling wind path. Further, a permeable or reflective baffle plate is provided within the light pipe. Further, the light pipe is formed by coating a mirror on an inner surface of an optical case integrally formed by fixing optical parts. Further, a dichroic mirror is arranged in an LED light source outgoing surface.

Abstract: In an illumination optical system and a color combining optical system of a projection apparatus using three image display elements, the object of the present invention is to reduce misconvergence of enlarged images displayed on a screen. The present invention provides a projection apparatus including light-detecting elements provided outside of an effective screen display area. An active region of image display elements for each color beam is controlled respectively based on results of the light-detecting elements in order to adjust display position of each color beam on the screen.

Abstract: An object of the present invention is to provide a projection-type image display apparatus improved in contrast. In order to achieve the above object, the present invention includes multiple LED elements, a controller for conducting control so that part of the multiple LED elements emit light, an image display element for forming a desired optical image from the light emitted from part of the LED elements, and a projector for projecting the optical image formed by the image display element.

Abstract: If a projection display device includes a shifting mechanism for shifting a projection lens to adjust the direction in which the display projects an optical image, it is difficult to find suitable position where the display should be installed. Thus, the projection lens is fitted with a projection angle adjusting mechanism, which includes an adjusting dial having a scale representing the position of the lens relative to a display element. The projection display device is capable of automatically displaying on the projected optical image a scale image corresponding to the scale. The projection display also is capable of displaying on the projected optical image the position of the optical axis of the projection lens, which can be shifted by the adjusting mechanism.

Abstract: A liquid crystal projector comprises an illuminating optical system including a light source, a color separating optical system for separating illuminating light rays emitted by the illuminating optical system into light rays of three colors, a projection lens unit comprising a projection lens, a cross dichroic prism disposed near a light receiving end of the projection lens, and a plurality of liquid crystal panels arranged around the cross dichroic prism, and a light source power supply for supplying power to the light source. The projection lens unit, the color separating optical system, the illuminating optical system and the light source power supply are arranged in that order. The liquid crystal projector has an outside size in a horizontal plane of 263 mm by 318 mm or below. The liquid crystal panels have a display screen size of 0.9 in. A cooling fan for cooling the plurality of liquid crystal panels is disposed beside the projection lens.

Abstract: By making the beam polarization state in a cross prism having a dichroic function for an incident beam on a reflection type liquid crystal panel the same as that for a reflected ON beam, a small-sized, low cost projection type projector apparatus is provided. A Faraday rotator having a Faraday rotation angle of 45 degrees is disposed on an optical path between a PBS and a cross prism. A half-wave plate having such a polarization axis as to rotate a polarization angle of linearly polarized light by 45 or 135 degrees is disposed on an optical immediately before or behind the Faraday rotator.

Abstract: A projection display according to the present invention reduces the size of a light beam in the optical path of an illumination optics from the periphery to change the amount of light incident on a video display device and the angle of such incidence, thereby making a plurality of image brightness/contrast combinations selectable. Further, the present invention changes the revolving speed of a projection display cooling fan and the adjustment value settings for the video display device's electrical characteristics in accordance with the aperture.