Abstract: An image-formation optical system is disclosed which is an off-axial optical system configured using reflective surfaces, with which the performance deterioration with respect to manufacturing discrepancies is reduced, and which can be made sufficiently compact. The image-formation optical system comprises a reflective optical unit including a plurality of reflective surfaces. Each of the reflective surfaces has a curvature and a rotationally asymmetric shape. Moreover, L/{Er(S?1)} is smaller than 2.2 and L/{Eo (S?1)} is larger than 3.

Abstract: It is an object of this invention to provide a high-quality, high-precision, large-screen display apparatus which can obtain a sufficient light beam reception angle with respect to an image display unit, improve imaging performance, and obtain a thin structure. There is provided a display apparatus for obliquely projecting light from an image display unit onto a projection optical system, wherein the projection optical system includes a plurality of aspherical curved mirrors and projects an image without distortion (1.2% or less).

Abstract: A projection optical system having a plurality of reflecting surfaces is disclosed in which a sufficiently large angle is provided between an incident side reference axis and an emerging side reference axis while tilt angles of the respective reflecting surfaces can remain small. The projection optical system projects luminous flux from an image forming element which forms an original image onto a projection surface. The incident side reference axis and the emerging side reference axis of the projection optical system are oblique to each other. The projection optical system has a plurality of reflecting surfaces each having a curvature. The reflecting surfaces are arranged such that the reference axis has at least one intersection in the projection optical system.

Abstract: A projection optical system which can project a bright image with less distortion and a small projection distance without causing aberration or an increase in size of reflective surfaces is disclosed. The projection optical system projects luminous flux from an original image onto a projection surface which is oblique to a central principal ray which is a principal ray of luminous flux traveling from the center of the original image to the center of a projected image. The projection optical system comprises a refractive optical system which includes a plurality of refractive optical elements through which the luminous flux from the original image passes through, and a reflective optical system which includes a plurality of reflective surfaces each having an optical power and guides the luminous flux emerging from the refractive optical system to the projection surface.

Abstract: A six-mirror catoptric projection optical system for projecting a reduced size of a pattern on an object onto an image plane includes first, second, third, fourth, fifth, and sixth mirrors from the image plane along an optical path, wherein the third and fourth mirrors are located between the fifth mirror and sixth mirror and wherein the catoptric projection optical system forms an intermediate image along the optical path from the third mirror to the fifth mirror.

Abstract: A projection optical system which has a short projection distance and a compact structure, and allows oblique projection. The projection optical system projects luminous flux from an image forming element for forming an original image onto a projection surface which is oblique to a central principal ray which is a principal ray of luminous flux traveling from the center of the original image to the center of a finally formed image. The system includes a plurality of reflecting surfaces each having a curvature. In addition, the projection optical system satisfies a predetermined expression (1).

Abstract: A catoptric projection optical system for projecting a reduced size of a pattern on an object surface onto an image surface and for serving as an imaging system that forms an intermediate image between the object surface and image surface, includes six or more mirrors, wherein a position of an exit pupil with respect to the intermediate image is located between the object surface and image surface, and wherein the largest angle between principal rays and an optical axis for angles of view at the position of the exit pupil is sin?1NA or smaller, where NA is a numerical aperture at the side of the image surface.

Abstract: It is an object of this invention to provide a high-quality, high-precision, large-screen display apparatus which can obtain a sufficient light beam reception angle with respect to an image display unit, improve imaging performance, and obtain a thin structure. There is provided a display apparatus for obliquely projecting light from an image display unit onto a projection optical system, wherein the projection optical system includes a plurality of aspherical curved mirrors and projects an image without distortion (1.2% or less).

Abstract: The invention discloses a projection optical system for projecting an original image onto a projection surface. The projection optical system comprises a plurality of aspherical curved mirrors, which reflects image light from the original image in sequence and then forms an image on the projection surface. The projection optical system forms a projected image on the projection surface at an aspect ratio different from that of the original image by a combination of reflective actions of the image light on the aspherical surfaces of the plurality of aspherical curved mirrors. Even in a projection optical system having a wide angle of view and a short distance of projection, it is possible to implement a projection optical system that is capable of suppressing distortion and performing an optical aspect conversion.

Abstract: An optical element formed from a transparent optical material includes two refraction surfaces, a first reflection surface group having a plurality of internal reflection surfaces arrayed in a predetermined direction, a second reflection surface group opposing the first reflection surface group and having at least one internal reflection surface and two side surfaces opposing each other in parallel to the predetermined direction. Light incident from one of the refraction surfaces is alternately reflected by the internal reflection surfaces of the first reflection surface group and the internal reflection surface of the second reflection surface group and guided to the other refraction surface.

Abstract: It is an object of this invention to provide a high-quality, high-precision, large-screen display apparatus which can obtain a sufficient light beam reception angle with respect to an image display unit, improve imaging performance, and obtain a thin structure. There is provided a display apparatus for obliquely projecting light from an image display unit onto a projection optical system, wherein the projection optical system includes a plurality of aspherical curved mirrors and projects an image without distortion (1.2% or less).

Abstract: A projection optical system includes an optical modulation unit which outputs modulated light for displaying an image, an optical scanning unit on which the modulated light output from the optical modulation unit is incident, the optical scanning unit scanning the light from the optical modulation unit to obtain a two-dimensional image, and a plurality of curved reflecting surfaces on which the light scanned by the optical scanning means is sequentially incident, the plurality of curved reflecting surfaces sequentially reflecting the light scanned by the optical scanning means and projecting the light on a projected surface, wherein when an optical path of a ray connecting a center of a pupil of the projection optical system and a center of a projected image is set as a reference axis, the reference axis is inclined with respect to a normal to the projected surface.

Abstract: A reflecting optical element is disclosed which includes the following articles. The reflecting optical element is constituted by: a base member having a continuous curved-surface portion, and a resin layer integrally formed of resin on the curved surface of the base member, and having a plurality of mutually discontinuous curved surfaces to be reflecting surfaces. The base member is made of a material smaller in coefficient of linear expansion than the resin for forming the resin layer. Thus, a reflecting optical element is provided which is low in optical-performance deterioration caused by the temperature effect, and small in the number of restraints in fabrication.

Abstract: An optical element comprising an object-side imaging element for imaging an object on an intermediate image plane in an optical path before a final image plane and an image-side imaging element for reimaging an object image formed on the intermediate image plane, on the final image plane, wherein at least one of the object-side imaging element and the image-side imaging element comprises an off-axial curved surface, and wherein aberration is generated by both of the object-side imaging element and the image-side imaging element, thereby flattening (disturbance of) a light intensity distribution caused on the final image plane by a noise source at or near the intermediate image plane.

Abstract: An image-formation optical system is disclosed which is an off-axial optical system configured using reflective surfaces, with which the performance deterioration with respect to manufacturing discrepancies is reduced, and which can be made sufficiently compact. The image-formation optical system comprises a reflective optical unit including a plurality of reflective surfaces. Each of the reflective surfaces has a curvature and a rotationally asymmetric shape. Moreover, L/{Er(S−1)} is smaller than 2.2 and L/{Eo (S−1)} is larger than 3.

Abstract: A compact image-forming optical system is disclosed which has a high optical performance due to arranging a reflective optical unit and a refractive optical unit at suitable positions. The image-forming optical system is an optical system performing image formation from a magnifying side to a demagnifying side or from the demagnifying side to the magnifying side, and includes, in order from the magnifying side to the demagnifying side, a refractive optical unit having a positive optical power as a whole, and a reflective optical unit including at least three reflective surfaces. The image-forming optical system has a pupil on the magnifying side further from the reflective surface furthest on the magnifying side the reflective optical unit, and the focal length of the refractive optical unit is set to be within a range of 0.2 to 5 times the focal length of the reflective optical unit.

Abstract: An image pickup unit for changing an orientation of an image pickup field by constructing a common portion as a unit. The image pickup unit preferably has an image pickup medium, an optical system through which an image of an object is formed, a reflecting member which is disposed at the position nearer the side of the object than that of the optical system, a reflecting member driver for driving the reflecting member, an interface for enabling communication with an apparatus main body which (i) has therein the image pickup unit and (ii) generates a signal to control an operation of the image pickup unit, and a microcomputer which (i) transmits information on the side of the image pickup unit to the apparatus main body and (ii) controls the reflecting member driver on the basis of the signal received from the apparatus main body. Preferably, the reflecting member driver drives the reflecting member, thereby changing the orientation of the image pickup field of the image pickup medium.

Abstract: A scan type display optical system is disclosed in which the position and inclination of an image formed by projection light is made variable. The scan type display optical system comprises an optical scanning member for deflecting and scanning light, and a projection optical system which includes a plurality of optical surfaces containing a reflective surface. The projection optical system projects light from the optical scanning member. An incidence range of light from the optical scanning member to a first optical surface on which the light is incident initially out of the plurality of optical surfaces is variable.

Abstract: A catoptric projection optical system for projecting a reduced size of a pattern on an object surface onto an image surface includes six mirrors that include a first convex mirror, a second mirror, a third mirror, a fourth mirror, a fifth mirror, and a sixth mirror in order of reflections of light, wherein the light incident upon the third mirror from the second mirror intersects with the light incident upon the fifth mirror from the fourth mirror.

Abstract: In a multi-eye camera head unit (10), a panoramic image sensing exchangeable camera head unit (111) and three-dimensional image sensing exchangeable camera head unit (112) are exchanged in correspondence with the image sensing mode. The panoramic image sensing exchangeable camera head unit (111) includes a pair of optical elements (111R, 111L), which comprise offaxial optical systems each having a plurality of reflecting and refracting surfaces. The three-dimensional image sensing camera head unit (112) includes a pair of optical elements (112R, 112L), which comprise offaxial optical systems each having a plurality of reflecting and refracting surfaces.