Abstract: An oblique projection optical system for leading rays of light from a display surface on which an image is displayed to a projection surface in such a way that the ray of light from the center of the display surface is obliquely incident on the projection surface in order to project a magnified image of the image displayed on the display surface onto the projection surface includes a plurality of reflecting surfaces having a power. At least two of the reflecting surfaces have a free-form curved surface, and, of all the reflecting surfaces, the one closest to the projection surface has a negative power and at least one of the other has a positive power. Alternatively, in a rear projection optical system having a projection optical system for projecting an image displayed on a panel display surface onto a screen surface, the projection optical system includes at least four curved-surface reflecting mirrors.

Abstract: An oblique projection optical system for leading rays of light from a display surface on which an image is displayed to a projection surface in such a way that the ray of light from the center of the display surface is obliquely incident on the projection surface in order to project a magnified image of the image displayed on the display surface onto the projection surface includes a plurality of reflecting surfaces having a power. At least two of the reflecting surfaces have a free-form curved surface, and, of all the reflecting surfaces, the one closest to the projection surface has a negative power and at least one of the other has a positive power. Alternatively, in a rear projection optical system having a projection optical system for projecting an image displayed on a panel display surface onto a screen surface, the projection optical system includes at least four curved-surface reflecting mirrors.

Abstract: A display optical apparatus is provided with: a polarizing plate transmitting illuminating light having a predetermined polarization direction; a reflective liquid crystal display device reflecting the illuminating light transmitted by the polarizing plate as projected light of a polarization condition that differs according to pixel information for each pixel; and a phase plate changing the polarization conditions of the illuminating light and the projected light and directing the illuminating light and the projected light to the polarizing plate. The phase plate is disposed between the reflective liquid crystal display device and the polarizing plate. The black level of the projected light is adjusted by rotating the principal axis direction of the phase plate.

Abstract: A color liquid crystal display device which separates white light in to component colors. The separated colors are modulated by a reflective liquid crystal display. A lens group between the light separator and the reflective liquid crystal display condenses the entering light to each pixel of the liquid crystal display. High brightness and aperture efficiency are achieved by including in the lens group a birefringent material so that a different optical function is performed relative to the entering light fluxes and the modulated light fluxes.

Abstract: A color integrating optical device for integrating different color rays from a plurality of display devices each of which has a condenser lens in front thereof and emitting the integrated color rays to a non-telecentric projecting optical system, including a dichroic mirror plate having a dichroic film, the dichroic mirror integrating the color rays by the dichroic film in which a color rays from one of display devices reflects thereon and another color rays from the other of display devices transmits thereon, the dichroic film being formed an incident surface of a color rays to be reflected, and a dummy plate provided on an optical path of color rays to be reflected by the dichroic film so that an unnecessary rays caused by part of the color rays being reflected at the dummy plate does not emit to the non-telecentric projecting optical system.

Abstract: An optical system has the first, second, and third lens units from an object side. The first and third lens units have positive refractive powers. The second lens unit has a negative refractive power. The second lens unit moves toward an image side during focusing from an object at an infinite distance to an object at a finite distance. The second lens unit has a sub lens unit. The sub lens unit moves in a direction perpendicular to an optical axis to correct an image shake.

Abstract: A zoom lens system for forming an image of an object on a solid state imaging device includes a first lens unit having a positive optical power and being movable in a zooming operation; a second lens unit having a negative optical power; and a third lens unit having a positive optical power. The system satisfies at least one the following conditions: 0.8<M1WM/M1MT<2.5; 0.2<&Dgr;&bgr;3/&Dgr;&bgr;2<1.0; 0.7<m1/Z<3.0; 1.0<img*R<15.0; 1.0<max(T1, T2, T3)<4; and 4.

Abstract: A color integrating optical device for integrating different color rays from a plurality of display devices each of which has a condenser lens in front thereof and emitting the integrated color rays to a non-telecentric projecting optical system, comprising a dichroic mirror plate having a dichroic film, the dichroic mirror integrating the color rays by the dichroic film in which a color rays from one of display devices reflects thereon and another color rays from the other of display devices transmits thereon, the dichroic film being formed an incident surface of a color rays to be reflected, and a dummy plate provided on an optical path of color rays to be reflected by the dichroic film so that an unnecessary rays caused by part of the color rays being reflected at the dummy plate does not emit to the non-telecentric projecting optical system.

Abstract: An illumination optical system has a light source that emits white light having random polarization planes, a polarization separation device that separates the light from the light source into two types of light having polarization planes perpendicular to each other and traveling in directions at an angle to each other, a wavelength-specific polarization conversion device that receives the two types of light thus separated and that then subjects the light of a particular wavelength range included in them to polarization conversion, a convergence optical system that receives the two types of light after the light of the particular wavelength range included therein has undergone polarization conversion and that then makes them converge on different convergence positions, and a half-wave plate disposed near one of those convergence positions.

Abstract: A projector has an illumination optical system, a reflection-type display panel, a projection optical system, and light-introducing device. The display panel is illuminated by the illumination light emitted from the illumination optical system and is divided into a plurality of pixels to reflect the incoming illumination light selectively in accordance with the pattern formed by those pixels and thereby produce projection light. The projection optical system transmits the projection light reflected from the display panel to project the pattern formed by the pixels onto a projection plane on which to form a projected image, and is composed of, from the projected-image side, a front lens unit, an aperture stop, and a rear lens unit. The light-introducing device is disposed between the front and rear lens units and directs the illumination light to the display panel. The projection optical system fulfills the condition 0.2≦&ggr;F≦0.

Abstract: A zoom lens system has the first to fifth lens units from the object side. Refractive powers of the first to fifth lens units are positive, negative, negative, positive, negative, respectively. During zooming, the distances between the lens units are varied. Image blur compensation is made by parallel decentering the second lens unit. When f2 is the focal length of the second lens unit, f5 is the focal length of the fifth lens unit, and fw is the focal length of the entire lens system, then the following conditions are satisfied. 0.2<|f2/fw|<4.0 0.2<|f5/fw|<0.

Abstract: A zoom lens system has the first to fifth lens units from the object side. Refractive powers of the first to fifth lens units are positive, negative, negative, positive, negative, respectively. During zooming, the distances between the lens units are varied. Image blur compensation is made by parallel decentering the second lens unit. The second lens unit includes a first lens unit and a rear lens unit, either of which can be moved vertically to the optical axis to compensate for image blur. The distance between the front and rear lens units is fixed during a zooming mode.

Abstract: A projecting optical system has a plurality of display panels, a color integrating mirror, a projection optical system, a correcting member, and a lens member. The color integrating mirror, disposed at an angle to any of the display panels, integrates the images displayed on the display panels into a single color-integrated image by reflecting a light component covering a specific wavelength range and transmitting light components covering other wavelength ranges than the specific wavelength range. The projection optical system projects the color-integrated image onto a screen. The correcting member, disposed within the projection optical system, corrects the astigmatic difference caused by the color integrating mirror. The lens member, disposed on the color-integrating-mirror side of the correcting member, corrects the astigmatic difference caused by the color integrating mirror.

Abstract: A display apparatus of the present invention includes: an illumination optical system for emitting illumination light; a reflective display panel divided into a plurality of pixels, illuminated by the illumination light from the illumination optical system, and selectively reflecting the incident illumination light pixel by pixel as projection light; a projection optical system for projecting image information the reflective display panel onto a projected surface by transmitting the projection light reflected at the reflective display panel; and a reflection angle converting optical system disposed ahead of the reflective display panel, changing the angle of incidence of the illumination light on the reflective display panel, and adjusting the sum of the angle of incidence of the illumination light on the reflective display panel and the angle of reflection of the projection light at the reflective display panel.

Abstract: A zoom lens system has, from the object side, a first lens unit having a optical power, a second lens unit having a negative optical power a third lens unit having a positive optical power, and a succeeding lens unit. The first and the third lens units monotonically move toward the object side during zooming from the shortest focal length condition to the longest focal length condition. A number of predetermined conditions are disclosed which can be satisfied to ensure a high quality, compact zoom lens for a digital camera.

Abstract: A projector optical system has a reflection-type display panel, an illumination optical system for illuminating the reflection-type display panel, and a projection optical system for projecting the images displayed on the reflection-type display panel onto a screen. The projection optical system has, from the screen side, a front lens unit and a rear lens unit. A light-deriving means for directing illumination light toward the reflection-type display panel is disposed between the front and rear lens units. Additionally, the following condition is fulfilled: 0.2<&phgr;F/&phgr;<0.9 where &phgr;F represents the optical power of the front lens unit of the projection optical system, and &phgr; represents the optical power of the entire projection optical system.

Abstract: Dichroic mirrors are disposed at the same inclination angle in a position such that a plane including an incidence optical path and a reflection optical path (transmission optical path of green light) of blue light reflected at a reflecting surface of one dichroic mirror is orthogonal to a plane including an incidence optical path and a reflection optical path of red light reflected at the other dichroic mirror. The other dichroic mirror is formed by cementing two glass substrates, and a red light reflecting layer is formed on the joint surface.

Abstract: A projector optical system has an illumination optical system, a dichroic surface, and a projection lens system. The dichroic surface is inclined with respect to the illumination principal ray traveling from the beam center of the illumination light emitted from the illumination optical system to the centers of the reflection-type display panels, and also with respect to the projection principal ray traveling from the centers of the reflection-type display panels to the center of the aperture stop of the projection lens system.

Abstract: A zoom lens system has four or five lens units with the optical powers being +/-/+/- or +/-/+/+/-, respectively, from the object side. The image side lens unit has a negative optical power and is movable, along with at least one other lens unit, in a zooming operation. The zoom lens system satisfies the following conditions: 0.6<LBw/fw<1.7 and 0.6<.vertline.fN/fw.vertline.<1.7, where LBw represents a back focus length at the shortest focal length condition; fw represents a focal length of the zoom lens system at the shortest focal length condition; and fN represents a focal length of the image side lens unit. The lens system can be employed with a solid state imaging device, and an optical low-pass filter and an infrared blocking filter can be positioned between the lens system and the imaging unit.

Abstract: A zoom lens system has from an object side a first lens group of a positive refractive power, a second lens group of a positive refractive power and a third lens group of a negative refractive power. The second lens group has from the object side a lens unit and a positive lens element convex to the object side. Focusing for a close object is performed by moving the lens unit toward the object side. In the zoom lens, the following condition is fulfilled: ##EQU1## where r1 is a radius of curvature of an object side surface of the positive lens element and r2 is a radius of curvature of an image side surface of the positive lens element.