Abstract: An optical element that is made of a transparent medium L1 rotationally symmetric relative to the central axis 2 with a refractive index greater than 1, wherein the transparent medium L1 has a first transmissive surface 11, a first reflective surface 12, a second reflective surface 13 arranged at an opposite side to the image plane 5 relative to the first reflective surface 12 and a second transmissive surface 14 arranged at the image plane 5 side relative to the second reflective surface 13 and that the flux of light entering the transparent medium L1 goes into it by way of the first transmissive surface 11 so as to be reflected to the opposite side to the image plane 5 by the first reflective surface 12 and then to the image plane 5 side by the second reflective surface 13 to form an optical path before going out from the transparent medium L1 at the image plane 5 side by way of the second transmissive surface 14 in the order of forward ray tracing.

Abstract: An optical element is made of a transparent medium that is rotationally symmetric relative to the central axis with a refractive index greater than 1. The transparent medium has a first transmissive surface at the outermost periphery relative to the central axis, a first reflective surface at the side of the central axis relative to the first transmissive surface, a second reflective surface at the side opposite to the image plane relative to the first reflective surface and a second transmissive surface at the side of the image plane relative to the second reflective surface. The flux of light enters and proceeds through the transparent medium via the first transmissive surface, the first reflective surface, the second reflective surface and the second transmissive surface to form an optical path. The optical path is formed only at a side relative to the central axis.

Abstract: A Fresnel optical element has a plurality of slopes that refract or reflect light, and the variation of the slope angle between adjacent slopes is constant.

Abstract: An optical system is adapted to form an image having a full 360° angle of view on an image plane. The optical system includes a front unit having at least two reflecting surfaces, each rotationally symmetric about a center axis, and a rear unit that is rotationally symmetric about the center axis and has positive power. The first reflecting surface is located opposite to an entrance pupil, and the second reflecting surface is located on the same side as the first reflecting surface. The entrance pupil in a section including the center axis is located between the outer periphery of the first reflecting surface and the outer periphery of the second reflecting surface. A light beam coming from afar passes through the front unit and the rear unit in order, forming an image at a position of an image plane off the center axis.

Abstract: The projection optical apparatus of the invention comprises a projection optical system 13 for projection of an image displayed on a two-dimensional image display device 13b; a cylindrical screen 11 which is decentered with respect to the projection optical system 13 and onto which an image projected from the projection optical system 13 is projected; and a correction optical system 12 including an optical device 12a that has different powers in the direction (Y-axis direction) of the center axis of rotation of the cylindrical screen 11 and in the direction (X-axis direction) orthogonal to a first plane 101 including a center chief ray C of a light beam traveling from the projection optical system 13 toward the cylindrical screen 11.

Abstract: The visual display apparatus of the invention has an image display device, a projection optical system for projection of an image displayed on the image display device, an eyepiece optical system of positive reflecting power that uses an image coming from afar as an image projected from the projection optical system, and a cylindrical or conical diffusing surface located near an image projected from the projection optical system. The image projected from the projection optical system is located in such a way as to draw a circular arc at any position in the plane orthogonal to the optical axis of the projection optical system.

Abstract: The invention provides a visual display apparatus 1 comprising an image display device 3, a projection optical system 4 adapted to provide an image on the image display device 3, and an eyepiece optical system 5 adapted to allow an image projected through the projection optical system 4 to be viewed as a faraway virtual image. The eyepiece optical system 5 comprises a diffusing surface 11 adapted to diffuse an image projected through the projection optical system 4, a reflective optical device 51 having at least one reflecting surface adapted to reflect an image diffused through the diffusing surface 11, and at least one rotationally asymmetric transmissive optical device 52 adapted to transmit an image reflected by the reflective optical device 52. The number of imaging differs at a certain first section, and at a second section orthogonal to the first section.

Abstract: In the visual display device of the present invention, the first reflection plane 11 is so disposed as to face the eye point 4 in order of an optical path of reverse tracing that extends from the eye point 4 to the two-dimensional image displaying plane 3; the second reflection plane 21 is so disposed as to face the two-dimensional image displaying plane 3, and an optical axis connecting the first reflection plane 11 to the eye point 4 is so disposed as to cross an optical axis connecting the second reflection plane 21 to the two-dimensional image displaying plane 3; both the first and second reflection planes 11 and 21 have positive power; and diopter difference S of the position of a virtual image associated with diopter is substantially equal to that of the position of a virtual image associated with convergence.

Abstract: A Fresnel optical element has a plurality of slopes that refract or reflect light, and the variation of the slope angle between adjacent slopes is constant.

Abstract: A flux of light entering a transparent medium proceeds along a side view optical path by way of a first transmissive surface so as to be reflected to the side opposite to an image plane by a first reflective surface and then to the image plane side by a second reflective surface to form an optical path before going out from the transparent medium to the outside at the image plane side by way of a second transmissive surface in the order of forward ray tracing and also along a direct view optical path by way of a third transmissive surface to form another optical path before going out from the transparent medium into the outside at the image plane side by way of a fourth transmissive surface also as viewed in the order of forward ray tracing.

Abstract: The invention relates to an optical system which is adapted to form an image having a full 360° (panoramic)-direction angle of view on an image plane or project an image located on an image plane in a full 360° (panoramic)-direction angle of view, and which is of small-format size and has reduced light flare and high resolving power. The optical system comprises a front unit (10) having at least two reflecting surfaces (11, 12), each rotationally symmetric about a center axis (1), and a rear unit (20) that is rotationally symmetric about the center axis and has positive power. The first reflecting surface (11) is located opposite to an entrance pupil (6Y), and the second reflecting surface (12) is located on the same side as the first reflecting surface (11). The entrance pupil (6Y) in a section including the center axis is located between the outer periphery of the first reflecting surface (11) and the outer periphery of the second reflecting surface (12).

Abstract: A visual display device includes an image display element 3 and an ocular optical system 5 that allows a viewer to observe an image displayed on the image display element 3 as a virtual image in a remote location. The ocular optical system 5 has at least one reflection optical element 5a, at least one transmission optical element 5b, and a visual axis 101 including a central main light beam in the reverse raytrace of the ocular optical system 5 which is directed from the center of an entrance pupil E toward the reflection optical element 5a through the transmission optical element 5b. The number of times of image formation is different between in a first cross-section including the visual axis 101 and in a second cross-section which is perpendicular to the first cross-section and includes the visual axis 101.

Abstract: The invention relates to an optical system which is adapted to form an image having a full 360° (panoramic)-direction angle of view on an image plane or project an image located on an image plane in a full 360° (panoramic)-direction angle of view, and which is of small-format size and high resolving power yet without being affected by flare light. The optical system comprises a front unit (10) having two reflecting surfaces and two transmitting surfaces, each rotationally symmetric about a center axis (1), a rear unit (20) that is rotationally symmetric about the center axis and has positive power, and an aperture (5) located coaxially with the center axis.

Abstract: The invention relates to an optical system with well corrected aberrations, which is adapted to take images from a full panoramic scene on a cylindrical, conical or other three-dimensional image surface or project such a three-dimensional display surface onto a full field of view in the distance. In an optical system adapted to form images from a 360° panoramic scene on a cylindrical or conical image surface 3, there is an annular refractive optical element 2 provided with the center axis 1 of rotation of the image surface 3 as the axis of rotational symmetry. There is further at least one reflective surface 4 provided with the center axis 1 of the rotation as the axis of rotational symmetry.

Abstract: The invention relates to an optical system adapted to project a cylindrical, spherical, conical or other three-dimensional display surface onto every direction in the distance or receive images from every direction at such a three-dimensional imaging surface. The optical system is adapted to project a three-dimensional object surface 3 onto a full circle in the distance, and comprises at least one rotationally symmetric reflective surface 2.

Abstract: In a projection optical system 4 for projecting an image being displayed on an image display element 3, the display surface of the image display element 3 and the projection surface of the projection optical system 4 are decentered in the Y-Z cross section and the projection surface is formed by means of a circular-arc-shaped curved surface with the chord thereof directed to the side of the projection optical system 4 in the X-Z cross section and the projection optical system 4 has at least a rotationally asymmetric corrective optical surface 5 for correcting the distortion of the image.

Abstract: An optical element is made of a transparent medium L1 that is rotationally symmetric relative to the central axis 2 with a refractive index greater than 1, in which the transparent medium L1 has a first transmissive surface 11 arranged at the outermost periphery relative to the central axis 2, a first reflective surface 12 arranged at the side of the central axis 2 relative to the first transmissive surface 11, a second reflective surface 13 arranged at the side opposite to the image plane 5 relative to the first reflective surface 12 and a second transmissive surface 14 arranged at the side of the image plane 5 relative to the second reflective surface 13, the flux of light entering the transparent medium L1 proceeds through it by way of the first transmissive surface 11, the first reflective surface 12, the second reflective surface 13 and the second transmissive surface 14 to form an optical path A in the order of forward ray tracing before going out from the transparent medium at the side of the image pla

Abstract: An optical element that is made of a transparent medium L1 rotationally symmetric relative to the central axis 2 with a refractive index greater than 1, wherein the transparent medium L1 has a first transmissive surface 11, a first reflective surface 12, a second reflective surface 13 arranged at an opposite side to the image plane 5 relative to the first reflective surface 12 and a second transmissive surface 14 arranged at the image plane 5 side relative to the second reflective surface 13 and that the flux of light entering the transparent medium L1 goes into it by way of the first transmissive surface 11 so as to be reflected to the opposite side to the image plane 5 by the first reflective surface 12 and then to the image plane 5 side by the second reflective surface 13 to form an optical path before going out from the transparent medium L1 at the image plane 5 side by way of the second transmissive surface 14 in the order of forward ray tracing.

Abstract: The invention relates to an optical apparatus allowing images in multiple directions to be simultaneously taken with simple construction using a prism optical system yet with high definitions even at wide angles of view. Specifically, the invention provides an optical apparatus using a prism optical system which has three optical surfaces: a first surface having transmission, a second surface having internal reflection plus transmission and a third surface having reflection and is formed of a medium having a refractive index of 1.3 or greater and in which light enters the medium through the first surface, is totally reflected at the second surface, and then reflected at the third surface 13, and finally leaves the medium this time through the second surface.

Abstract: A flux of light entering a transparent medium L2 proceeds along a side view optical path A by way of the first transmissive surface 21 so as to be reflected to the side opposite to the image plane by the first reflective surface 22 and then to the image plane side by the second reflective surface 23 to form an optical path before going out from the transparent medium L2 to the outside at the image plane 5 side by way of the second transmissive surface 24 in the order of forward ray tracing and also along a direct view optical path B by way of third transmissive surface 25 to form another optical path before going out from the transparent medium L2 into the outside at the image plane 5 side by way of the fourth transmissive surface 26 also as viewed in the order of forward ray tracing.