Abstract: An image display apparatus has a reflective display element for displaying a two-dimensional image on a display plane, a light source for emitting illuminating light for illuminating said display plane, a magnifier optical system for magnifying and projecting said two-dimensional image, and an optical member which is composed of a medium having a refractive index greater than or equal to unity and has at least three optical planes of a first plane, a second plane, and a third plane. The magnifier optical system is substantially in concentricity with said display plane; the illuminating light from said light source passes through said first plane and then through said second plane, thereby illuminating said display plane; and the reflected light from said display plane passes through said second plane and is then reflected in said first plane, thereby passing through said third plane and being incident on said magnifier optical system.

Abstract: A projecting image display device is disclosed which includes a display and a micro lens array, where the pixels of the display and the micro lens elements each have non symmetric properties in length and width directions. The micro lens concentrates color-separated light onto pixels of a display device so that light does not hit the black matrix. By providing a display having pixels which are not equal in length and width, pixels corresponding to red (R), green (G) and blue (B) can be arranged in a substantially square area, and by providing a micro lens array which has non symmetric properties in length and width, the color separated light can be concentrated onto the non square display pixels.

Abstract: A liquid crystal projector includes an illumination optical system provided with a light source, first and second lens arrays arranged in this order from the light source, a liquid crystal panel, and a polarization changing optical system arranged between the first and second lens arrays. This makes it possible to install the polarization changing optical system and the optical integrator in a smaller space.

Abstract: A display apparatus has a picture displaying portion and a temperature providing portion. The temperature providing portion generates heat. The picture displaying portion displays a picture based on a video signal generated by a picture information generating portion.

Abstract: A liquid crystal projector includes an illumination optical system provided with a light source, first and second lens arrays arranged in this order from the light source, a liquid crystal panel, and a polarization changing optical system arranged between the first and second lens arrays. This makes it possible to install the polarization changing optical system and the optical integrator in a smaller space.

Abstract: An optical deflection device for deflecting light by a mirror mounted on the tip of a rod-like torsion spring which oscillates at near resonance frequency. An optical deflection device which produces a large amplitude by exerting control to avoid variation in the natural oscillation frequency of the torsion spring (including mirror) regardless of temperature fluctuation.

Abstract: A focusing method for a decentered optical system including a decentered lens element has translationally moving and inclining at least one lens element for different object distances, in such a way that variation in a position of a primary image point is kept within a range defined by the following condition.

Abstract: An oblique projection optical system, having a wide field angle and high magnification, includes a compact optical system that provides sufficient inclination projection angle. The optical system includes a plurality of lens elements that optically interact to reduce trapezoid distortion.

Abstract: An image display apparatus has a display unit and an eyepiece optical system. The display unit displays a two-dimensional image. The eyepiece optical system projects the two-dimensional image into an observer's pupil to enable the observer to view an enlarged virtual image of the two-dimensional image. The optical axis of the eyepiece optical system is decentered from the visual axis of the observer's pupil.

Abstract: A projecting optical system projects an image formed on a primary image plane obliquely onto a secondary image plane. The projecting optical system has a plurality of partial optical systems decentered from each other. The projecting optical system also has a plurality of zoom optical systems. The zoom optical systems are moved to continuously vary an image magnification. During the movement, the secondary image plane is kept in a fixed position.

Abstract: A projection display apparatus has a reflective type display for displaying a two-dimensional image on a display surface, a projection optical system for projecting an enlargement image of the two-dimensional image displayed on the display surface onto a projection image surface, the projection optical system having a diaphragm and a decentering optical element disposed between the diaphragm and the reflective type display and decentered with respect to the diaphragm, and wherein the predetermined conditions are satisfied when an image center ray is defined by a line connecting a center position of the display surface and the center position of the projection image surface.

Abstract: A scanning-type image viewing optical system has a light source for emitting luminous flux; a main scanning means for scanning luminous flux in a first direction; a sub-scanning means for scanning luminous flux in a second direction different from the first direction; and an eyepiece lens for directing luminous flux scanned by the two scanning means to the pupil of an observer, wherein the main scanning means has a conjugate relationship with the pupil position of the observer via the eyepiece lens, and when the pupil diameter, i.e., the luminous flux diameter of the incident luminous flux at the pupil position of the observer, is designated d and the main scan diameter, i.e., the luminous flux diameter exiting the main scanning means, is designated d', the conjugate magnification .beta. calculated by d/d' satisfies the conditional equation .beta..ltoreq.0.85.

Abstract: A scanning-type image viewing optical system has a light source for emitting luminous flux; a main scanning means for scanning luminous flux in a first direction; a sub-scanning means for scanning luminous flux in a second direction different from the first direction; and an eyepiece lens for directing luminous flux scanned by the two scanning means to the pupil of an observer, wherein the main scanning means has a conjugate relationship with the pupil position of the observer via the eyepiece lens, and when the pupil diameter, i.e., the luminous flux diameter of the incident luminous flux at the pupil position of the observer, is designated d and the main scan diameter, i.e., the luminous flux diameter exiting the main scanning means, is designated d', the conjugate magnification .beta. calculated by d/d' satisfies the conditional equation 1.2.ltoreq..beta..

Abstract: An illumination optical system has a light source unit, a first array having a plurality of two-dimensionally arranged cells which deflect a incident light from the light source unit and a second array having a plurality of cells two-dimensionally arranged in a vicinity of a focal plane of the first array, wherein at least one of the first array and the second array is formed as a reflection array.

Abstract: An overhead projector provides an unobstructed view of projected images by minimizing the vertical dimension of the projector and provides sufficient brightness of projected images by minimizing the loss of light. The light emitted from a light source housed in the body of the projector is reflected by a first reflection mirror and directed, through a transparent stage on which a transparent original is placed, to a second reflection mirror. Meanwhile, on the transparent stage, the principal ray axis of the light beam forms an angle .theta. with respect to the center axis of the surface of the transparent original. After reaching the second reflection mirror and being reflected thereby, the light is condensed into a projection lens unit, and is projected therefrom onto a screen to form thereon an image of the transparent original.

Abstract: A projection optical device includes a projection optical system for projecting an image of an object plane onto a screen without forming an intermediate real image. The projection optical system includes a coaxial first lens group to be arranged relatively near the object plane, a coaxial second lens group to be arranged relatively near the screen, and a stop arranged between the first and second lens groups. The second lens group has an optical axis inclined with respect to an optical axis of the first lens group. A magnification .beta.1 of the first lens group satisfies a relationship of .vertline.1/.beta.1.vertline.<0.05. The second lens group is angularly deviated from the first lens group around a position of the stop.

Abstract: An imaging optical system transmits a primary image. The optical system does not form an intermediate image. The primary image is projected on a screen as a secondary image. The optical system has a projection optical system and a reflection optical system. An optical axis of the reflection optical system forms an angle other than 90.degree. with respect to a screen-side image surface.

Abstract: A projecting optical device which simultaneously projects one object onto two or more different screens has a first screen, a second screen, a first projecting optical system which projects the object onto the first screen, and a second projecting optical system which projects the object onto the second screen and does not share an optical element with the first projecting optical system. A first base line connecting the center of the object to the center of the image projected on the first screen by the first optical system and a second base line connecting the center of the object to the center of the image projected on the second screen by the second optical system are not parallel to each other.

Abstract: A zoom lens system of the invention is double telephoto type zoom lens system having a positive/negative/positive/negative refractive power arrangement. During zooming from the wide angle side toward the telephoto side, the first through fourth lens units move such that the distance between the first and second lens units increases and the distance between the third and fourth lens units decreases. The refractive power of the first lens unit and the refractive power of the fourth lens unit are appropriately prescribed so that an adequate back focal lens distance is preserved.

Abstract: The present invention relates to a zoom lens system used for photo-taking in a 35 mm single lens reflex camera. The zoom lens system consists of, from the object side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power. Zooming from a wide-angle side to a telephoto side takes place by moving all of the first lens unit through the fourth lens unit to the object side. Focusing on an object at a short distance is performed by moving the second lens unit to the object side.