Abstract: A projection optical system including a first optical system configured to form a second image conjugate to a first image and a second optical system configured to include a reflective optical element which reflects light from the second image and to project a third image conjugate to the second image onto a projection surface is provided, wherein the first optical system has a Petzval sum with a sign opposite to a sign of a Petzval sum of the second optical system.

Abstract: A projection optical system for use in an image projection apparatus illuminating a lightbulb forming an image in accordance with a modulating signal with illumination light from a light source is disclosed. The projection optical system includes first and second optical systems arranged along an optical path defining an upstream-downstream direction in the order described from upstream to downstream on the downstream side of the lightbulb. The first optical system includes at least one dioptric system and has positive power. The second optical system includes at least one reflecting surface having power and has positive power. The image formed by the lightbulb is formed as an intermediate image in the optical path, and the intermediate image is magnified and projected.

Abstract: In a projection optical system for use in an image projection apparatus illuminating an image display panel forming an image in accordance with a modulating signal with illumination light from a light source, the projection optical system includes first and second optical systems arranged along an optical path defining an upstream-downstream direction in the order described from upstream to downstream on the downstream side of the image display panel. The first optical system includes at least one dioptric system and has positive power. The second optical system includes at least one reflecting surface having power and has positive power. The image formed by the image display panel is formed as an intermediate image in the optical path, and the intermediate image is magnified and projected.

Abstract: A disclosed projection optical system for projecting and forming an enlarged image of an image displayed in a planar manner as an object includes: a lens system including, from an object side, at least a lens group providing telecentricity to an object space side, a lens group controlling divergence of angles of view, a diaphragm, a lens group converging the angles of view, and a lens group converging and subsequently enlarging the angles of view; and a catoptric system disposed on an image side relative to the lens system and including a mirror having negative power. Each lens group of the lens system and the mirror having negative power share an optical axis and the optical axis is shifted relative to a center of an object surface.

Abstract: A projection optical system for use in an image projection apparatus illuminating a lightbulb forming an image in accordance with a modulating signal with illumination light from a light source is disclosed. The projection optical system includes first and second optical systems arranged along an optical path defining an upstream-downstream direction in the order described from upstream to downstream on the downstream side of the lightbulb. The first optical system includes at least one dioptric system and has positive power. The second optical system includes at least one reflecting surface having power and has positive power. The image formed by the lightbulb is formed as an intermediate image in the optical path, and the intermediate image is magnified and projected.

Abstract: A disclosed optical path switching device includes a polarization bistable VCSEL that emits a beam having a rising polarization plane, a laser light source configured to emit a beam having a polarization plane orthogonal to the rising polarization plane, and an optical path switching unit configured to switch an optical path of the beam emitted from the polarization bistable VCSEL by switching the angle of the rising polarization plane of the beam emitted from the polarization bistable VCSEL. The beam emitted from the polarization bistable VCSEL is incident on an entrance window of the optical path switching unit, and the beam emitted from the laser light source is incident on an exit window of the polarization bistable VCSEL.

Abstract: An image display device is disclosed that has a simplified structure and is able to display a high quality image of high resolution at low cost. The image display device includes a light separation unit configured to extract a light beam having a predetermined wavelength band from light emitted from a light source; a light valve that controls a light beam incident thereon to form a plurality of sub frames of a target image; and a light path shift unit operable to shift a light path of an output light beam from the light valve having the predetermined wavelength band according to a frame period of the target image to locate one or more sub frame of the target image at different positions from other sub frames of the target image formed by the light valve.

Abstract: A document illuminating system includes a plurality of light emitting elements arranged in an array, a reflective element which guides light emitted from the light emitting elements to a document read area of a certain width and length. The reflective element includes first to third reflective portions. The second reflective portion includes one or more planar reflective faces and is disposed so that the reflective faces reflect light from the light emitting elements to one or both of the first and third reflective portions without other reflective elements. The first and third reflective portions each include one or more planar reflective faces and are disposed so that their reflective faces oppositely illuminate the document read area together by reflecting light from one or both of the light emitting elements and the second reflective portion to the document read area without other reflective elements.

Abstract: A projection optical apparatus capable of providing high image quality and having a reduced size. The projection optical apparatus comprises a light valve and a projection optical system including a first optical system (5) having a transmissive-refractive element and a second optical system (3?) having a reflective-refractive element. An image formed on the light valve is projected by the projection optical system on a projection surface (4). The optical axis in the first optical system (5) is folded both vertically and horizontally. The first group (5A) of the first optical system is contained in a space (dead space) whose lower limit is defined by a lower edge of the second optical system (3?)/thereby reducing the depth of the apparatus.

Abstract: An image display apparatus acquires a high-quality image by suppressing positional fluctuation of projected dots due to a positional offset of an optical path deflecting element. A spatial light modulation element (1) displays an image by projecting a light from an illumination light source. A projection optical system (3) enlarges and projects the image formed on the spatial light modulation element (1). An optical path deflecting element (2) is provided between the spatial light modulation element (1) and the image formed on a screen (4) so as to deflect an optical path in accordance with a screen frame period. The optical path deflecting element (2) shifts the optical path for the image projected on the screen (4) at a high rate so as to apparently increase a number of picture elements. The optical path deflecting element (2) is located within the projection optical system.

Abstract: A projection optical system comprising a first optical system configured to form a first image conjugated with an object and a second optical system configured to project a second image conjugated with the first image toward a projection surface, in which at least one of the first optical system and second optical system comprises at least one optical element(s) movable relative to the object is provided, wherein an image distance of the projection optical system is changed and a size of the second image is changed, by moving at least one of the optical element(s) relative to the object.

Abstract: A projection optical system for use in an image projection apparatus illuminating a lightbulb forming an image in accordance with a modulating signal with illumination light from a light source is disclosed. The projection optical system includes first and second optical systems arranged along an optical path defining an upstream-downstream direction in the order described from upstream to downstream on the downstream side of the lightbulb. The first optical system includes at least one dioptric system and has positive power. The second optical system includes at least one reflecting surface having power and has positive power. The image formed by the lightbulb is formed as an intermediate image in the optical path, and the intermediate image is magnified and projected.

Abstract: A disclosed reflective screen is configured to display an image projected from a projection device located within a short distance. The reflective screen comprises a first reflective surface configured to reflect, in a substantially same direction, projection light beams projected from a first position, and a second reflective surface configured to reflect, in the substantially same direction, projection light beams projected from a second position different from the first position.

Abstract: A projection optical system for use in an image projection apparatus illuminating an image display panel forming an image in accordance with a modulating signal with illumination light from a light source. The projection optical system includes first and second optical systems arranged along an optical path defining an upstream-downstream direction in the order described from upstream to downstream on the downstream side of the image display panel. The first optical system includes at least one dioptric system and has positive power. The second optical system includes at least one reflecting surface having power and has positive power. The image formed by the image display panel is formed as an intermediate image in the optical path, and the intermediate image is magnified and projected.

Abstract: A projection optical system for use in an image projection apparatus illuminating an image display panel forming an image in accordance with a modulating signal with illumination light from a light source. The projection optical system includes first and second optical systems arranged along an optical path defining an upstream-downstream direction in the order described from upstream to downstream on the downstream side of the image display panel. The first optical system includes at least one dioptric system and has positive power. The second optical system includes at least one reflecting surface having power and has positive power. The image formed by the image display panel is formed as an intermediate image in the optical path, and the intermediate image is magnified and projected.

Abstract: A projection optical system for use in an image projection apparatus illuminating an image display panel forming an image in accordance with a modulating signal with illumination light from a light source. The projection optical system includes first and second optical systems arranged along an optical path defining an upstream-downstream direction in the order described from upstream to downstream on the downstream side of the image display panel. The first optical system includes at least one dioptric system and has positive power. The second optical system includes at least one reflecting surface having power and has positive power. The image formed by the image display panel is formed as an intermediate image in the optical path, and the intermediate image is magnified and projected.

Abstract: A light path shift device is disclosed that is able to divide an effective region of a light path and drive the divided regions independently. The light path shift device includes a liquid crystal layer held between at least two opposite transparent substrates, the liquid crystal layer being homeotropically aligned and being able to form a chiral smectic C phase; and plural electrodes for applying an electric field in the liquid crystal layer in a horizontal direction. An effective region of the liquid crystal layer through which a light path passes is divided into plural sub-regions, plural light path shift elements with the electrodes formed thereon are stacked only at positions corresponding to the sub-regions, and are arranged so that boundary lines of the sub-regions are in agreement when being viewed along the direction of light propagation.

Abstract: A micro-optical device includes a plurality of minute optical elements each having a curved surface operable to condense incident light. The minute optical elements are arranged at constant intervals. The curved surface is expressed by two or more F values. Each of the minute optical elements is a transmission lens element having the curved surface including a substantially flat part at a center of the transmission lens element, wherein the curved surface is convex or concave.

Abstract: A disclosed projection optical system for projecting and forming an enlarged image of an image displayed in a planar manner as an object includes: a lens system including, from an object side, at least a lens group providing telecentricity to an object space side, a lens group controlling divergence of angles of view, a diaphragm, a lens group converging the angles of view, and a lens group converging and subsequently enlarging the angles of view; and a catoptric system disposed on an image side relative to the lens system and including a mirror having negative power. Each lens group of the lens system and the mirror having negative power share an optical axis and the optical axis is shifted relative to a center of an object surface.

Abstract: A disclosed projection optical system for projecting and forming an enlarged image of an image displayed in a planar manner as an object includes: a lens system including, from an object side, at least a lens group providing telecentricity to an object space side, a lens group controlling divergence of angles of view, a diaphragm, a lens group converging the angles of view, and a lens group converging and subsequently enlarging the angles of view; and a catoptric system disposed on an image side relative to the lens system and including a mirror having negative power. Each lens group of the lens system and the mirror having negative power share an optical axis and the optical axis is shifted relative to a center of an object surface.