Abstract: A display optical system for guiding light from an image to an observer or a surface projecting an image thereon with a first optical system and second optical system. The first optical system having a first surface formed on a transparent body with a reflecting action, a second surface reflecting light reflected on the first surface toward the first surface again, and a third surface formed on the transparent body transmitting light from the image. The light transmitted through the third surface travels toward the first surface and is reflected for the first time. In addition, a principal ray, central angle of view to be reflected for the last time on the first surfaces is reflected to a side opposite a side of the first reflection on the first surface with respect to a normal line of a surface on a hit point thereof.

Abstract: An image observation apparatus is constructed to project image information displayed on an image display device for displaying the image information, onto a retina of an observing eye by a display optical system, thereby permitting an observer to observe the image information, and to perform control to change a position of an incident beam onto the entrance pupil plane of the observing eye. The apparatus is arranged to detect the position of the observer's pupil and change the position of the incident beam onto the entrance pupil plane of the observing eye, based on the result of the detection.

Abstract: A three-dimensional photonic crystal operating at a plurality of design wavelengths, in which the photonic band gap can be adjusted to a desired wavelength band without changing the lattice period, and an optical element that can contain a defect resonator or a defect waveguide in the three-dimensional photonic crystal are provided.

Abstract: A three-dimensional periodic structure exhibiting a complete photonic band gap in a wide wavelength range and being readily produced, as well as a functional element including the same, is provided. In the three-dimensional periodic structure exhibiting a photonic band gap according to the present invention, layers composed of a plurality of columnar structures spaced at predetermined intervals are stacked sequentially with additional layers therebetween. Discrete structures contained in the additional layers are disposed at the positions corresponding to the intersections of the columnar structures, and the area of the discrete structure is larger than the area of the intersection region of the above-described columnar structures.

Abstract: An image observation system includes a pair of image observation devices for the left and right eyes of an observer. Each of the image observation devices includes an image pickup system which forms an image on a image pickup device using an image pickup optical system, and a display system which guides the light from the image acquired by the image pickup system to an observers eye by a display optical system. Each of the image observation devices is arranged so that the outside optical axis of the image pickup optical system is approximately aligned with an extension line of the eye-side optical axis of the display optical system. In the image observation system, the image pickup device included in the image pickup system of each image observation device is shifted horizontally by a predetermined distance relative to the optical axis of the image pickup optical system, and the display element is shifted horizontally by a predetermined distance relative to the optical axis of the display optical system.

Abstract: Provided is a small size, high resolution display element with an extremely high utilization efficiency of light emitted by a light source unit and a high contrast. A display element of the present invention has a photonic crystal, a light source unit, and a control unit. The control unit changes the resonance wavelength of point defect resonators formed within the photonic crystal, thus effecting a control between a state in which light guided from the light source unit to a linear defect waveguide is emitted to the outside of the photonic crystal, and a state where emission of light to the outside of the photonic crystal is blocked.

Abstract: A three-dimensional periodic structure exhibiting a complete photonic band gap in a wide wavelength range and being readily produced, as well as a functional element including the same, is provided. In the three-dimensional periodic structure exhibiting a photonic band gap according to the present invention, layers composed of a plurality of columnar structures spaced at predetermined intervals are stacked sequentially with additional layers therebetween. Discrete structures contained in the additional layers are disposed at the positions corresponding to the intersections of the columnar structures, and the area of the discrete structure is larger than the area of the intersection region of the above-described columnar structures.

Abstract: A three-dimensional periodic structure exhibiting a complete photonic band gap in a wide wavelength range and being readily produced, as well as a functional element including the same, is provided. In the three-dimensional periodic structure exhibiting a photonic band gap according to the present invention, layers composed of a plurality of square columns spaced apart by a predetermined interval are stacked sequentially with additional layers therebetween, rectangular parallelepipeds contained in the additional layers are disposed at the positions corresponding to the intersections of the square columns, and 1.21?W1/W?2.39 and W/W1<W2/W are satisfied, where W1 and W2 represent lengths of sides of the rectangular parallelepiped and W represents the width of the square column, each in a plane parallel to the layer containing the square columns.

Abstract: Disclosed is an image observation system including a pair of image observation devices each having i) an image pickup device, ii) an image pickup optical system for directing light rays from an outside world to the image pickup device, iii) a display device for displaying an outside world image obtained by the image pickup system, and iv) a display optical system for directing light from the display device to an observing eye, wherein the optical axis of the image pickup system and the optical axis of the display system are disposed coaxially, wherein the optical axes of the image pickup systems of the pair of image observation devices define a point of intersection, and wherein a focal plane being at a position conjugate with a surface of the image pickup device with respect to the image pickup optical system is disposed at a side of the intersection point of the optical axes of the image pickup systems, which side faces an observer, such that an outside world image obtained by the image pickup system can be

Abstract: A small optical system that is capable of widening an angle of view is provided. This optical system is provided with a first surface having a reflecting action and a second surface that reflects a light beam reflected on this first surface toward the first surface again. Then, a principal ray at central angle of view that is made incident on the first surface again is reflected and travels to a side opposite to a side of the last time it was reflected from the first surface with respect to a normal line of a surface at a hit point thereof.

Abstract: An image display apparatus has an image display for displaying a parallax image, and a display optical system for guiding light from the image display to the position of the exit pupil. The exit pupil is spatially and temporally divided into a plurality of areas, a passing beam to each area is controlled, and control is effected on switching between parallax images on the image display means corresponding to passing beams through the respective areas of the exit pupil, whereby a plurality of parallax images are perceived by a single eye of an observer.

Abstract: A display optical system for guiding light from an original picture to an eye of an observer or a surface to have an image projected thereon is provided with a first optical system and a second optical system. The first optical system is provided with a first surface that is formed on a transparent body and has at least a reflecting action, a second surface for reflecting light reflected on the first surface toward the first surface again, and a third surface that is formed on the transparent body in the same manner as the first surface and transmits the light from the original picture. The light transmitted through the third surface travels toward the first surface and reflected for the first time on the first surface. In addition, a principal ray at central angle of view to be reflected for the last time on the first surface is reflected and travels to a side opposite to a side of the first reflection on the first surface with respect to a normal line of a surface on a hit point thereof.

Abstract: An image display apparatus has a reflective display device, an illumination optical system with a reflective surface A for guiding light from a light source to the display device, and a display optical system for guiding light from the display device to an observer's observation position and is constructed to permit an observer to observe image information displayed on the display device. The image display apparatus is constructed in appropriate setting of principal rays emerging from a display surface of the display device and impinging upon the center of the exit pupil, illumination principal rays emerging from the light source and guided to the display surface by the illumination optical system to become principal rays, angles of incidence and emergence of the illumination principal rays and the principal rays to and from the display surface, an angle between the reflective surface A and the display surface, angles of incidence of the illumination principal rays to the reflective surface A, and so on.

Abstract: An image display apparatus has a light source, a reflective display device, an illumination optical system for guiding light from the light source to the display device to illuminate the display device, and a display optical system for guiding the light reflected by the display device to the pupil of an observer to allow the observer to observe an image displayed on the display panel. The illumination optical system and the display optical system have an optical element shared in part or are arranged so as not to interfere with each other, thereby providing the image display apparatus of compact structure. Particularly, where the display optical system is a thin optical system having a plurality of decentered, reflecting, curved surfaces, the appropriate illumination optical system is arranged, thereby providing the thin image display apparatus using the reflective display device.

Abstract: An image observation apparatus is constructed to project image information displayed on an image display device for displaying the image information, onto a retina of an observing eye by a display optical system, thereby permitting an observer to observe the image information, and to perform control to change a position of an incident beam onto the entrance pupil plane of the observing eye. The apparatus is arranged to detect the position of the observer's pupil and change the position of the incident beam onto the entrance pupil plane of the observing eye, based on the result of the detection.

Abstract: An image display apparatus has a reflective display device, an illumination optical system with a reflective surface A for guiding light from a light source to the display device, and a display optical system for guiding light from the display device to an observer's observation position and is constructed to permit an observer to observe image information displayed on the display device. The image display apparatus is constructed in appropriate setting of principal rays emerging from a display surface of the display device and impinging upon the center of the exit pupil, illumination principal rays emerging from the light source and guided to the display surface by the illumination optical system to become principal rays, angles of incidence and emergence of the illumination principal rays and the principal rays to and from the display surface, an angle between the reflective surface A and the display surface, angles of incidence of the illumination principal rays to the reflective surface A, and so on.

Abstract: An image display apparatus has a light source, a reflective display device, an illumination optical system for guiding light from the light source to the display device to illuminate the display device, and a display optical system for guiding the light reflected by the display device to the pupil of an observer to allow the observer to observe an image displayed on the display panel. The illumination optical system and the display optical system have an optical element shared in part or are arranged so as not to interfere with each other, thereby providing the image display apparatus of compact structure. Particularly, where the display optical system is a thin optical system having a plurality of decentered, reflecting, curved surfaces, the appropriate illumination optical system is arranged, thereby providing the thin image display apparatus using the reflective display device.

Abstract: An image observing apparatus is arranged to observe outside information from the outside and a display image displayed on an image display device via an optical combiner and via an eyepiece lens superimposed. The outside information and the display image are imaged so as to be superimposed on a surface of a spatial modulator having a two-dimensional pixel structure. Part or all of the outside information and display image is selected on an area basis by the spatial modulator. The outside information and image information thus selected is observed through the eyepiece lens.

Abstract: A composite display apparatus has a display device for displaying image information, a display optical system for guiding light from the display device to the eye of an observer, and an image pickup optical system for focusing light from the outside on an image pickup device. An optical axis of the image pickup optical system is substantially aligned with an axis that is an extension of the eye-ball optical axis in an optical path of the display optical system. The apparatus further has an optical path separating element for separating an optical path of the image pickup optical system from the optical path of the display optical system. Each of the display optical system and the image pickup optical system has a plurality of decentered reflective surfaces having curvature. The light from the display device is alternately folded in directions along the eye-ball optical axis by the plurality of reflective surfaces of the display optical system to be guided to the eye.

Abstract: An image observing apparatus is arranged to observe outside information from the outside and a display image displayed on an image display device via an optical combiner and via an eyepiece lens superimposed. The outside information and the display image are imaged so as to be superimposed on a surface of a spatial modulator having a two-dimensional pixel structure. Part or all of the outside information and display image is selected on an area basis by the spatial modulator. The outside information and image information thus selected is observed through the eyepiece lens.