Abstract: An object of the invention is to provide a compact yet high-performance finder optical system comprising an image inversion optical subsystem having a decentered reflecting surface, which enables a bright, distortion-free image to be observed. This object is achieved by locating a rotationally asymmetric surface in the image inversion optical subsystem forming part of the finder optical system.

Abstract: A multiview three-dimensional image display system comprises an image projection screen, two image generation components, a bifold mirror, an spatial light modulator, and projection optics. Each of the image generation components generates successive finite time sequences of time-multiplexed multiview images and thus form a channel of multiview images. Each of the reflecting surfaces of the bifold mirror reflects a different one of the two channels of multiview images. The spatial light modulator comprises a plurality of strip-like shutters, each of which transmits a different one of the finite time sequences of time-multiplexed multiview images. The projection optics projects the images through the spatial light modulator onto the image projection screen, where the spatial light modulator is imaged to make a single viewing zone.

Abstract: A viewfinder optical system for conducting light from an object to an observer includes a plurality of reflecting surfaces having optical powers. Optical paths of each ray of a light flux reflected successively by the plurality of reflecting surfaces intersect each other at least twice, and the light from the object forms an image at least twice when passing through the viewfinder optical system.

Abstract: A high-performance image-forming optical system made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. The image-forming optical system has a first prism placed on the object side and a second prism placed on the image side and does not form an intermediate image. The first prism has a first surface through which a light beam enters the first prism, a second surface reflecting the incident light beam in the prism, a third surface reflecting the reflected light beam in the prism, and a fourth surface through which the light beam exits from the prism. At least one of the second and third surfaces has a rotationally asymmetric curved surface configuration that gives a power to a light beam and corrects aberrations due to decentration. The second prism has at least one reflecting surface that reflects a light beam in the prism.

Abstract: A head mounted display system includes focusing optics to focus light from an image source, retro-reflector and beamsplitter, the image source and beamsplitter directing light toward the retro-reflector to focus a real image, and the light reflected from the retro-reflector being directed via the beamsplitter for viewing, thereby to use conjugate optics effectively to place the viewing eye or detector in relation to the image source the same as the relation of the focusing optics to the image source. The retro-reflector may be mounted on a common housing or support with the beamsplitter and focusing optics or it may be remotely located. A method for forming an image using conjugate optics in which light from a source is focused to form a real image at a retro-reflector and is reflected for viewing.

Abstract: A head mounted display to view a created image and an external scene includes a display displaying the image and a prism receiving the image which includes a first surface for diffracting the image, and a second and third surface reflecting the image to a user of the head mounted display.

Abstract: A high-performance image-forming optical system made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. The image-forming optical system has a first prism placed on the object side and a second prism placed on the image side and does not form an intermediate image. The first prism has a first surface through which a light beam from an object enters the first prism, and a second surface that reflects the light beam entering through the first surface in the first prism. The first surface also reflects the light beam reflected by the second surface in the first prism. The first prism further has a third surface through which the light beam reflected by the first surface exits from the first prism. The first or second surface has a rotationally asymmetric surface configuration that gives a power to a light beam. The second prism has at least one reflecting surface that reflects a light beam in the second prism.

Abstract: The invention improves on an ocular having at least one spatially modulating, reflective device at one of the possible locations of an intermediate image plane. Emphasis is on the ocular containing the reflective device, rather than that device's function. A list of device functions include nonlinear image light modulation; optical power limiting; planar image processing; reticle, grid or text superposition. All such functions require sharp image focus on the device surface plane. A polarizing beamsplitter, quarter-wave plate means, field lens and roof prism are combined to simultaneously improve optical energy efficiency, sharpen focus and reduce keystoning at the reflective device while increasing the field-of-view for the virtual image of observed scenery.

Abstract: An image display apparatus that presents an observer an image of higher resolution than the original resolution of an image display device used, thereby allowing the observer to view a clear and beautiful image. An illuminating optical system (5) illuminates an image display device with illuminating light from a light source (1). The image display device displays an image by transmission or reflection of the illuminating light. A viewing optical system leads the image to an observer's eyeball (10). The apparatus has two image display devices (9a and 9b). An optical coupling/separating element having a light-coupling or light-separating action is provided between the image display devices (9a and 9b) and the observer's eyeball (10) to superimpose images of the two image display devices on one another. The optical coupling/separating element has an optical coupling/separating surface (40) tilted at an angle of approximately 45 degrees with respect to each of the image display devices (9a and 9b).

Abstract: An omnidirectional visual sensor which can observe a 360-degree panoramic field area, obtain a sharp image and correctly transform a central projection with respect to the image and can be minimized as a whole includes a convex mirror with a surface of revolution having a focal point, a plurality of mirrors with surfaces of revolutions having at least one focal point, a photoreceiving lens system receiving light reflected by the convex mirror with the surface of revolution and the plurality of mirrors with surfaces of revolutions and an image acquisition surface receiving the light received in the photoreceiving lens system and converting the same to an electric signal, and the convex mirror with the surface of revolution and the plurality of mirrors with surfaces of revolutions are so arranged that the focal point of a first mirror included in the convex mirror with the surface of revolution and the plurality of mirrors with surfaces of revolutions aligns with the focal point of a second mirror, included in

Abstract: An optical element has a plurality of reflecting regions for reflecting light in succession, each of the plurality of reflecting regions comprises a curved surface, at least two of the reflecting regions has a common reflecting surface, and the optical paths of the light defined by the plurality of reflecting regions intersect with one another.

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 decentered prism optical system suitable for use as an ocular optical system used in combination with an objective optical system and favorably corrected for pupil aberration. A prism optical system (7) which receives an image formed by an objective lens includes a decentered prism (7) having at least three surfaces (3 to 5) decentered with respect to each other, wherein the space between the at least three surfaces (3 to 5) is filled with a transparent medium having a refractive index not smaller than 1.3. The optical path is reflected at least twice in the optical system (7), and the optical paths of light rays do not intersect each other. At least one reflecting surface (4) has a rotationally asymmetric surface configuration having no axis of rotational symmetry in nor out of the surface. The optical system has both the function of optically transmitting a pupil (1) by image formation and the function of optically transmitting an image and is satisfactorily corrected for pupil aberration.

Abstract: A miniature microscope is extremely small, fitting in a palm of a user's hand while providing powerful magnification and enhanced brightness so that the details of an object which cannot be resolved by an unaided eye can be easily seen. The microscope includes a housing have a holder for supporting an object to be viewed. At least one light source is position in the housing off-axis with respect to the object to be viewed. A first prism includes a first prism surface for reflecting light from the light source to a beam splitter surface wherein the beam splitter surface reflects light from the first prism surface to the object to be viewed. The beam splitter surface also passes light reflected from the object therethrough to a second prism. The second prism is positioned with respect to the first prism to provide refraction correction.

Abstract: A visual display device is provided for delivering a generated image, preferably combinable with environment light, to the eye of a user. Light from an image generator such as a CRT, LED or LCD is reflected from a fold mirror away from a user's eye towards a combiner. The image is reflected from the combiner and magnified, optionally combined with light from the environment and passes back through the fold mirror towards the eye of the user. In one embodiment, an optical element such as a meniscus lens or PCX lens is used to present the user with a substantially flat focal field and/or a Fresnel lens or diffractive optical element is used to aim rays from the image to the field curvature corrective lens in order to maintain maximum contrast.

Abstract: An apparatus that efficiently and accurately splits a laser beam input into eight or more outputs where the beam energies of the output beams are within ten and preferably within five percent of each other. The apparatus includes an arrangement of at least seven beam splitters each of which can split an incident laser beam into two exit beams of equal energy at a particular incident angle. At least some of the splitters have different particular incident angles but the particular incident angle of the first splitter is used as the incident angle for all splitters. The exit beams of the first splitter are directed to second and third splitters that have particular incident angles relatively close to the particular incident angle of the first splitter when compared with the relationship of the particular incident angle of the first splitter to the particular incident angles of the remaining splitters.

Abstract: A compact, lightweight, multi-wavelength display system which can be used as a collimating eyepiece is provided. The system utilizes a polarization selective optical element, or PS element, that reflects one linear polarization state while transmitting radiation of the orthogonal linear polarization state. The PS element is used in combination with a quarter wave plate and an optical element, the optical element including a partially reflective surface. The optical element may either be a single element or an optical doublet. In the latter configuration, the partially reflective surface is at the interface between the two singlets that comprise the doublet. The system also includes an image source that either alone, or in combination with other optical elements, produces circularly polarized light of the desired rotary sense.

Abstract: The present invention relates to an image display device (1) comprising a two-dimensional display (3; 19, 21; 72) and an optical system (5; 15, 17; 60). The optical system comprises a lens having a first semitransparent reflecting surface (23, 25; 9) and a second semitransparent reflecting surface (27, 29; 11). The first surface is directed towards the display. The second surface is directed towards the viewer. Both the display and the lens are divided into a plurality of segments in order to increase the field of view.

Abstract: A display rerouting apparatus reroutes a displayed image from an image source in a display module for providing a redirected angular visibility for the displayed image. In an illustrative embodiment, the display rerouting apparatus includes a base panel having a rectangular opening or widow for positioning atop of a display module in communication equipment, a rear panel having a one-way reflective mirror positioned in a rectangular opening in this rear panel, and a front panel having a two-way reflective mirror positioned in a rectangular opening in this front panel. Both the rear and front panels are respectively hingeably attached at their lower edges to the rear and front edges of the base panel for facilitating the use of the rerouting apparatus on different types of communication. In operation, the image from the display module is projected through the base of the apparatus onto the two-way reflective mirror.

Abstract: A virtual image display system is provided which is made thinner through the use of an immersed beam splitter, and in one embodiment, total internal reflection. The display system includes an imaging surface on which a source object is formed, a first optical element having a reflective function and a magnification function, a second optical element having a magnification function and an immersed beam splitting element positioned between the first and second optical elements, the immersed beam splitting element including a beam splitter surrounded by an optically transparent material having a refractive index greater than air. An illumination source projects the source object formed at the imaging surface through the optically transparent material to the beam splitter. The beam splitter reflects the projected source object to the first optical element. The first optical element magnifies the projected source object and reflects a magnified virtual image of the projected source object to the beam splitter.

Abstract: An optical element including a first surface, a second surface, and a third surface, at least one of the first surface, the second surface, and the third surface being a curved surface, and at least one of the first surface, the second surface, and the third surface being a reflecting surface. Also included are side surfaces disposed opposite to each other, and positioning members for positioning the optical element, the positioning members being provided on the side surfaces.

Abstract: An optical unit 1 includes a liquid crystal panel 2, a back light 3, a reflecting mirror 4, a lens 5, and a casing 6 for accommodating these constituents therein. The optical unit 1 can be arranged in front of either the left eye or the right eye of the user. A half mirror 8 disposed below the optical unit 1 reflects an image beam emitted from the optical unit 1 toward an eye 10 of the user and transmits a light beam from the background view. The eye of the user which observes a virtual image is changed by shifting the optical unit 1 to the left eye or to the right eye.

Abstract: A decentered prism optical system has a first surface at a side thereof closer to a pupil. The first surface has a transmitting or reflecting action and also has a wide effective area. The first surface is formed from a rotationally symmetric spherical or aspherical surface. The optical system has at least three surfaces (3, 4 and 5), and the space between these surfaces (3 to 5) is filled with a transparent medium having a refractive index larger than 1.3. A bundle of light rays from an object first passes through a pupil (1) of the optical system (7) along an optical axis (2) and enters the optical system (7) through a first surface (3) having both transmitting and reflecting actions. The incident light rays are reflected toward the pupil (1) by a second surface (4) which is at a side of the optical system (7) remote from the pupil (1) and which has only a reflecting action. The reflected light rays are then reflected away from the pupil (1) by the first surface (3).

Abstract: An image display apparatus providing an observation image which is clear and has minimal distortion even when an ocular optical system having a decentered reflecting surface is arranged to provide a wide observation field angle. At least one reflecting or transmitting surface in the ocular optical system of the image display apparatus has a rotationally asymmetric surface configuration having not more than two planes of symmetry which satisfies various conditions defining a surface configuration.

Abstract: A virtually imaged phased array (VIPA) operating as a wavelength splitter to separate individual carriers from a wavelength division multiplexed (WDM) light. The VIPA has first and second surfaces. The second surface has a reflectivity which causes a portion of light incident thereon to be transmitted therethrough. The VIPA receives an input light at a respective wavelength within a continuous range of wavelengths. The first and second surfaces are positioned so that the input light is reflected a plurality of times between the first and second surfaces to cause a plurality of lights to be transmitted through the second surface. The plurality of transmitted lights interfere with each other to produce an output light which is spatially distinguishable from an output light produced for an input light having any other wavelength within the continuous range of wavelengths.

Abstract: The present invention relates to an image display apparatus suitable for a head mounted display which apparatus has been made compact as a whole by the use of a reflection type liquid crystal display element. The apparatus has a first optical element which has an incidence surface on which a light beam is incident, at least two curved reflecting surfaces made eccentric with respect to each other for reflecting the light beam incident from the incidence surface, and an emergence surface from which the light beam from the curved reflecting surfaces emerges. A reflection type image display device provided on the incidence surface side. A light beam from a light source is caused to enter from one of the two curved reflecting surfaces which comprises a half mirror surface, and emerge from the incidence surface and illuminate the image display device.

Abstract: The present invention is an optical apparatus, e.g. an image display apparatus, which enables observation of a clear image at a wide field angle with substantially no reduction in the brightness of the observation image, and which is extremely small in size and light in weight and hence unlikely to cause the observer to be fatigued. The optical apparatus has an image display device (6), and an ocular optical system (7) for leading an image of the image display device (6) to an observer's eyeball (1). The ocular optical system (7) includes, in order from the image side, a third surface (5) which forms an entrance surface, a first surface (3) which forms both a reflecting surface and an exit surface, and a second surface (4) which forms a reflecting surface. The first to third surfaces (3 to 5) are integrally formed with a medium put therebetween which has a refractive index larger than 1.

Abstract: An image display apparatus which enables observation of a clear image at a wide field angle, and which is extremely small in size and light in weight and hence unlikely to cause the observer to be fatigued. The image display apparatus has an image display device (7) and an ocular optical system for projecting the image of the image display device and leading the projected image to an observer's eyeball (1) The ocular optical system has, in the order of backward ray tracing, a first surface (3) which is a refracting surface, a second surface (4) which is a decentered reflecting surface of positive power, a third surface (5) which is a decentered reflecting surface, and a fourth surface (6) which is a refracting surface. At least two of the four surfaces have a finite curvature radius. A space formed by the first to fourth surfaces (3 to 6) is filled with a medium having a refractive index larger than 1.

Abstract: The invention provides a prism optical system which has an image-forming action and provides a clear yet substantially undistorted image at a wide field angle. In a prism optical system 5 comprising an aperture 1 and having an action on erecting an image formed by an objective, there are provided reflecting surfaces 31, 32, 33, 41, 42, and 43 for image inversion, each of which is constructed of a curved surface having a power, and is in an irrotationally symmetric plane shape having no rotationally symmetric axis both within and outside the surface, so that decentering aberration produced by reflection of light at the curved surfaces can be corrected.

Abstract: The invention provides an optical system which is well corrected in terms of both curvature of field and coma at a field angle of about 120.degree. and a pupil diameter of about 15 mm and may be applied to both image pickup and ocular systems. Dioptric elements 11 are located the pupil plane side E and/or image plane side I of a concentric element 12 including two semitransparent surfaces 121 and 122, said two semitransparent surfaces 121 and 122 being concave on the pupil plane side E and located such that they transmit light at least once and reflect light at least once.

Abstract: Multiple channel optical multiplexing/demultiplexing devices that utilize only a single constant, non-variable wavelength-selective optical interference filter have many advantages. The wavelength-selective optical filter is a conventional fixed wavelength optical interference filter having an angle shift property wherein the wavelength-selectivity changes with changing angles of incidence upon the filter. Because such filters are transparent to a different center wavelength depending on the angle of incidence of a light beam, multiplexing/demultiplexing is achieved by varying the angle of incidence of the light beam upon a single, constant and non-variable optical interference filter. Many different systems can be designed to transmit a light beam at multiple varied angles of incidence upon a single interference filter. Two such exemplary systems utilize a multiple-reflection chamber adapted to transmit a light beam at successively varied angles of incidence upon a single interference filter.

Abstract: A display system including a retro-reflector, and optical means including a projection lens and an accommodation feature for directing light from an image source to the retro-reflector, light reflected by the retro-reflector being provided for viewing, said optical means and retro-reflector being cooperative to establish a conjugate optics path including the accommodation feature along which the light is directed to the eye or eyes of a viewer for viewing of an image, the accommodation feature includes a conjugation lens means and it and the retro-reflector are cooperatively positioned such that as light passes back through the conjugation lens means along the same path it would have followed had the retro-reflector been placed at the image plane of the projection lens had the conjugation lens means not been in position. A servo system for moving the projection lens and the retro-reflector according to a transfer function also may be included.

Abstract: A miniature display system uses a reflective micro-display that reflects light perpendicular to the surface of the display to generate an image. Light from an off-axis light source is polarized and reflected by a prism to provide on-axis illumination light for the display. The prism uses total internal reflection and/or a polarizer as a beam splitting surface so as to increase the brightness of the image generated by the display. The optical system provides a virtual image with a large field of view so that the small display system can be used in portable, hand-held or head mounted systems to display a large amount of information to the user.

Abstract: A prism optical system for use as an ocular optical system of a visual display apparatus, which has a compact size as a whole, causes a minimal reduction of the light intensity in the ocular optical system, provides a wide field angle and a large exit pupil diameter, and is effectively corrected for off-axis aberrations. The prism optical system has two transparent surfaces (6 and 7), and two reflecting surfaces (2 and 3). The space between the first transparent surface (6) and the second transparent surface (7) is filled with a medium having a refractive index not smaller than 1.3.

Abstract: A head-mounted image display apparatus capable of providing an observation image which is clear and has minimal distortion even at a wide field angle. Display light from an image display device (7) enters an optical system (8) through a first surface (3) serving as both transmitting and reflecting surfaces. The incident light is reflected by a third surface (5) and further reflected by the first surface (3). Then, the reflected light is reflected by a second surface 4 which is a decentered reflecting surface disposed on an optical axis (2) to face an exit pupil (1). The reflected light exits from the optical system (8) through the first surface (3), travels along the optical axis (2) and enters an observer's pupil placed at the exit pupil (1), without forming an intermediate image, thus forming a display image on the retina of the observer's eye.

Abstract: The present invention relates to a reflecting optical system, wherein the reflecting optical system comprises a first reflecting surface having a positive power and a second reflecting surface having a negative power, wherein at least one of the surfaces is inclined and the reflecting optical system comprises a substantially afocal optical system of the surfaces.

Abstract: A head-mounted image display apparatus capable of providing an observation image which is clear and has minimal distortion even at a wide field angle. The apparatus has an image display device (6), and an ocular optical system (7) for leading an image formed by the image display device (6) to an observer's eyeball position without forming an intermediate image so that the image can be observed as a virtual image. The ocular optical system (7) has at least one reflecting surface (4) having reflecting action. The at least one reflecting surface (4) has a surface configuration defined by a plane-symmetry three-dimensional surface which has no axis of rotational symmetry in the surface nor out of the surface, and which has only one plane of symmetry.

Abstract: A virtual image display system is provided which is made thinner through the use of an immersed beam splitter, and in one embodiment, total internal reflection. The display system includes an imaging surface on which a source object is formed, a first optical element having a reflective function and a magnification function, a second optical element having a magnification function and an immersed beam splitting element positioned between the first and second optical elements, the immersed beam splitting element including a beam splitter surrounded by an optically transparent material having a refractive index greater than air. An illumination source projects the source object formed at the imaging surface through the optically transparent material to the beam splitter. The beam splitter reflects the projected source object to the first optical element. The first optical element magnifies the projected source object and reflects a magnified virtual image of the projected source object to the beam splitter.

Abstract: A visual display device is provided for delivering a generated image, preferably combinable with environment light, to the eye of a user. Light from an image generator such as a CRT, LED or LCD is reflected from a fold mirror away from a user's eye towards a combiner. The image is reflected from the combiner and magnified, optionally combined with light from the environment and passes back through the fold mirror towards the eye of the user. In one embodiment, an optical element such as a meniscus lens or PCX lens is used to present the user with a substantially flat focal field and/or a Fresnel lens or diffractive optical element is used to aim rays from the image to the field curvature corrective lens in order to maintain maximum contrast.

Abstract: An imaging system for viewing indicia on an object to be observed in which the indicia comprises a plurality of either hard and/or soft marks. The light supplied by a light source is collimated by at least one lens and supplied toward an object to be observed and the reflected light is then focussed at a focal plane. The focal plane is located adjacent or coincident with a light receiving entrance of a camera or other imaging device. When a soft mark is imaged, the light is supplied at an angle to but not along the optical axis and is focussed by the lens to from an accurate image of the light source at the focal plane. Any light which contacts the unaltered specular reflective surface of the object to be observed as well as the central area of the soft mark facilitates a true and accurate reflection of the light source at the focal plane while the altered, non-flat areas of the object to be observed at least partially scatter or disperse the supplied light.

Abstract: A head mounted display for entering an image into the eye of a viewer along a viewing axis. The head mounted display has a light source for supplying unpolarized light to an optical path. Also provided is a first polarizer disposed in the optical path for rotating the unpolarized light to that of a first polarization. A second polarizer is also disposed in the optical path for blocking light of the first polarization from reaching the eye. A reflective light valve is disposed in the optical path for rotating the light of the first polarization to an image of a second polarization. Also provided is a concave mirror disposed in the optical path for focusing and reflecting the image of the second polarization. Lastly, a directing means is provided for directing the light of the first polarization to the reflective light valve, for directing the image of the second polarization to the concave mirror, and for directing the focused and reflected image from the concave mirror towards the second polarizer.

Abstract: An optical apparatus includes a display for displaying image information, a display optical system having a plurality of reflection surfaces for guiding a light beam from the display to an eyeball of an observer, an image sensor, an image pickup optical system having a plurality of reflection surfaces for focusing a light beam from an external field to form an image on the image sensor, and an optical path separating surface for separating an optical path in the display optical system and an optical path in the image pickup optical system from each other in opposite directions. Thus, image information provided on the display can be viewed by the observer, and a scene in the external field can be taken in the image sensor.

Abstract: Low-cost complex plastic optics allow biocular viewing of video images generated by a single electro-optic display device, such as in a head-mounted display (HMD) for commercial or medical viewing applications. A dual off-axis configuration uses nearly collimated illumination optics and intermediate imaging optics to fill both eyepieces from a single display device without the need for a beamsplitter. Multiple illumination schemes are provided for either monochrome or color, and in either two-dimensional or time-sequential true stereographic presentation. Light from multicolor sources is superimposed, mixed, and homogenized by mixing light cones with diffractive collectors. Offsetting color overcorrection and undercorrection of individual optical elements achieves overall chromatic correction with minimal optical element complexity. A wireless video signal interface eliminates excess cabling.

Abstract: This invention is directed to a phototaking optical system including a solid optical element having a refraction incident surface on incident surface on which light from an object is incident, a plurality of curved reflection surfaces which sequentially reflect the light from the refraction incident surface, and a refraction exit surface from which the light from the curved reflection surfaces emerges, wherein at least one of the refraction incident surface and the refraction exit surface is a rotation asymmetrical surface.

Abstract: An optical element including a first surface, a second surface, and a third surface, at least one of the first surface, the second surface, and the third surface being a curved surface, and at least one of the first surface, the second surface, and the third surface being a reflecting surface. Also included are side surfaces disposed opposite to each other, and positioning members for positioning the optical element, the positioning members being provided on the side surfaces.

Abstract: An image display apparatus corrected for distortions, particularly, a distortion which is asymmetric with respect to the center of the image field. The apparatus includes an image display device (8), and an ocular optical system (42) having a rotationally asymmetric optical surface or a decentered optical surface having a power. The apparatus satisfies the condition of .vertline.tan .THETA..sub.1 -tan .THETA..sub.2 .vertline./tan .THETA..sub.1 <0.1, where .THETA..sub.1 is an angle made between a light ray emitted from an arbitrary point (44) on the image display device (8) and passing through the center of an exit pupil (40) and a visual axis (41), that is, a straight line connecting the center of an observer's pupil and the center of a projected image of the image display device (8), and .THETA..sub.

Abstract: An ocular optical system suitable for a head- or face-mounted image display apparatus which is compact, lightweight and satisfactorily corrected for aberrations, and in which no intermediate image is formed. The image display apparatus includes an image display unit (9) and an optical system (10) for projecting a displayed image into an eyeball (7). The optical system (10) is arranged such that light rays which are emitted from the image display unit (9) and enter the eyeball (7) are reflected at least three times by surfaces (12, 13 and 14) having power in backward ray tracing.

Abstract: A compact virtual image electronic display system is provided which includes a microdisplay for producing a source object, one or more magnification optics, and a distance adjusting mechanism for adjusting a distance between the one or more magnification optics and each other or a reflective surface, the magnification of the compound magnified image relative to the source object being dependent on this distance. The system may include a distance sensing mechanism for sensing the distance between the beamsplitting magnification optic and the reflective element and communicating the distance to a control mechanism which modifies the source object in response. The system can also include a control mechanism for causing the distance adjusting mechanism to adjust the distance in response to the source object produced by the microdisplay. The system can also include a user selectable input for modifying the source object.

Abstract: An apparatus is provided for magnifying a display surface of an indicator and forming an image of the display surface at a forward place distant from a driver and other passengers in a motor vehicle. The apparatus comprises an indicator (11), a concave mirror (15), and a half mirror (13). The concave mirror (15) and the half mirror (13) serve to enlarge an image (20) of a display surface (12) of the indicator (11) and form the enlarged image at a forward place distant from a driver and passengers in a vehicle. The apparatus is provided with a cylindrical lens portion (14) by which the magnifying power of the image (20) in right and left directions is set at 1.2 to 2.5 while the magnifying power in up and down directions is set at 1.2 to 1.6.

Abstract: A virtual image display system is provided which is made thinner through the use of an immersed beam splitter, and in one embodiment, total internal reflection. The display system includes an imaging surface on which a source object is formed, a first optical element having a reflective function and a magnification function, a second optical element having a magnification function and an immersed beam splitting element positioned between the first and second optical elements, the immersed beam splitting element including a beam splitter surrounded by an optically transparent material having a refractive index greater than that of air. An illumination source projects the source object formed at the imaging surface through the optically transparent material to the beam splitter. The beam splitter reflects the projected source object to the first optical element.