Abstract: 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 image, and which is extremely small in size and light in weight and hence unlikely to cause the observer to be fatigued. The apparatus includes an image display device (6) and an optical system (5) for projecting an image displayed by the image display device (6) and for leading the projected image to an observer's eyeball (7). The optical system (5) includes a first optical element (3) filled with a medium having a refractive index larger than 1. The first optical element (3) has, in the sequence of backward ray tracing, a first surface (11) serving as both a refracting surface and an internally reflecting surface; a second surface (12) which is a reflecting surface decentered or tilted with respect to an observer's visual axis (2); and a third surface (13) which is a refracting surface closest to the image display device (6).

Abstract: An optical system combines a first image formed by a main lens with a second image provided by an electronic display, slide, or other image source. The image combining system includes one or more inserts such as a set of reflecting image combiners to redirect light on an optical pathway within the main lens to the user's eye. The image combining system is highly compact, allowing the integration of a display system with eyeglasses or a face mask, such as a diver's mask. A number of implementations of the optical system make possible other types of image integration including uses in image acquisition systems such as cameras.

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 focussed 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: 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 information display apparatus comprising goggles and a terminal and having a dot density so high as to be capable of reproducing textual information is disclosed, in which the goggles include light sources, a fixed mirror and a rotary mirror arranged in such a manner as to satisfy predetermined conditions, and the data transmitted from the terminal are reproduced as an image.

Abstract: The present invention provides a head-mount image display apparatus which is maximumly reduced in size so as to arrange eyepiece optical systems in limited spaces such that the eyepiece optical systems do not touch the user's nose. The head-mount image display apparatus comprises LCD for displaying images for left and right eyes, eyepiece optical systems for guiding the images for left and right eyes displayed on the LCD to left and right eyeballs, body of the display apparatus for supporting the LCDs and the eyepiece optical systems for the left and right eyes such that the LCD and the eyepiece optical system for the right eyepiece is arranged at a predetermined distance from the LCD and the eyepiece optical system for the left eye, wherein corners of the eyepiece optical systems, at least which face a user's nose, are each provided with a chamfered portion planed off so as not to touch the user's nose.

Abstract: A wide angle large reflective unobscured system includes a primary reflective element for receiving a broad range of energy, a secondary reflective element for reflecting the energy from the primary reflective element to reimage a virtual entrance pupil at a real aperture stop. A beamsplitter element is provided for reflecting a first portion of the energy, such as visible energy, to a first tertiary reflective mirror, while transmitting a second portion of the energy, such as IR light, to a second tertiary reflector. Each tertiary reflector is capable of focusing the received energies to dual focal planes wherein a compact detector array assembly can convert the images to electronic signals.

Abstract: The line bow phenomenon is reduced by appropriately setting the reflective surface and/or the external shape of an optical element (e.g., a toric mirror) thereby realizing approximately linear illumination of the surface of the original document that is being read. In order to do this, optical elements can be formed so that the external shape of the reflective surface of the optical element is bow-shaped. Alternatively, the optical element can be arranged so that the optical axis of the reflective surface is parallel to the axis of the light reflected from the reflective surface.

Abstract: An aviator's helmet-mounted display includes a visor/combiner module (14) which is configured for use with an essentially standard aviator's flight helmet (12). The helmet-mounted display also includes a conformal image source and relay optics (ISRO) module (30) which is removably attachable to the aviator's helmet. This ISRO module (30) projects an image inwardly from outside the visor/combiner module through a transparent window portion (44) thereof and out and inner surface (48) of an angulated transparent viewing portion (18,20) of the visor/combiner module (14). The image is focused at infinity and is partially reflected from the inner surface (48) to an eye (50) of the aviator so that the image is superimposed on the aviator's view of an outside scene viewed through the viewing portion (18,20).

Abstract: A head-mounted display device (10) offers light weight, a low center of gravity, and low moments of inertia about the azimuthal and elevational axes of head movement. The display device (10) employs an angulated beam splitter mirror (16) disposed between a user's (22) eye (20) and an inner combiner surface (18a) of a visor (28). A projector (36) is carried laterally of the user's eye with a low center of gravity and a position close to the horizontal axis of elevational movement of the head. This projector (36) includes an image source (12) and an compact light-weight relay optics module (14) along with a projection fold mirror (30) disposed at eye level and laterally of the beam splitter mirror (16) to project image light to the beam splitter mirror (16). The beam splitter mirror (16) reflects the light onto the inner surface (18a) of the combiner (18) for reflection back through the beam splitter mirror (16) and to the user's eye (20).

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: A compact head mount display where an image display means and a magnifying reflecting mirror are substantially symmetrically arranged to a combiner, so that an image displayed on the display means and an outside image can be observed in a magnified and superimposed manner. The magnifying reflecting mirror is arranged as a Fresnel reflecting mirror so that the display becomes more compact. An optical system for use in the head mount display where the magnifying reflecting mirror is arranged as an aspherical surface and the shape of the aspherical surface is so designed that aberrations can be suitably 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: This invention provides a catadioptric optical system for achieving excellent imaging performance to obtain a resolution of quartermicron order. The catadioptric optical system is an optical system for transferring a reduced image of a pattern on a first plane onto a second plane and includes a beam splitter, an input lens group for guiding a light beam having a predetermined wavelength from the first plane to the beam splitter, an output lens group for guiding the light beam from the beam splitter to the second plane, a first concave mirror having an enlargement magnification, and a second concave mirror having a reduction magnification. The first concave mirror is arranged in an optical path of the light beam incident from the input lens group on the beam splitter and passing through the beam splitter to cause the passing light beam to be incident on the beam splitter again.

Abstract: The invention relates to an optical system which is compact and light in weight with well corrected aberrations, and is suitable for use on an image display device designed to form no intermediate image, and an optical system best usable as an ocular optical system for use on a head- or face-mounted image display device. This optical system comprises an optical element 7 and a diffraction optical element 8 that are mutually decentered. Optical element 7 comprises at least three juxtaposed optical surfaces, at least one of which is constructed of a curved surface. Between the optical surfaces at least two reflections occur. Spaces between the optical surfaces are filled with a medium having a refractive index greater than 1.

Abstract: The invention relates to an ocular optics system which forms no intermediate image, is reduced in terms of size and weight with well-corrected aberrations, and is best suited for use on face- or head-mounted image display devices, and provides an ocular optics system 7 comprising three juxtaposed optical surfaces 3, 4 and 5, wherein a space defined by three optical surfaces 3, 4 and 5 is filled with a transparent medium having a refractive index greater than 1, at least two optical surfaces 3 and 4 of these three optical surfaces are defined by curved surfaces concave on a pupil position side of the optics system, and at least four reflections occur between curved surfaces 3 and 4.

Abstract: The graded dielectric combiner, such as for a dual heads up display (HUD) combiner, is fabricated by depositing a predetermined number of dielectric layers upon a substrate and by thereafter selectively removing at least some of the dielectric layers from a graded portion of the dielectric combiner. As a result, the number of dielectric layers disposed upon the substrate will vary across the graded portion of the combiner. More specifically, the graded portion of the combiner may include a number of bands. A predetermined percentage of each band includes the predetermined number of dielectric layers, while the remainder of each band includes less than the predetermined number of dielectric layers. Since the dielectric layers are deposited in a conventional fashion, however, the thickness of each remaining dielectric layer will be uniform across the substrate.

Abstract: A compact and lightweight head- or face-mounted image display apparatus in which curvature of field is reduced to improve visibility without using a relay optical system or a prism. The image display apparatus has an image display device (1) and an optical system for leading an image displayed by the image display device (1) to an observer's eyeball (5) without effecting image formation on the way to the observer's eyeball (5). The image display device (1) and the optical system are retained on an observer's head or face by a retaining device. Light rays from the image display device (1) are reflected by a semitransparent surface (2) and then reflected by a reflecting surface (4) of a back-coated mirror (3). Thereafter, the light rays pass through the semitransparent surface (2) to enter the observer's pupil (5).

Abstract: A compact image display system in which the optical pathway is folded and thereby extended between the image source and the imaging optics of the system. The image display system may be used in place of computer or television screens, and may further be affixed to a frame so that it is wearable by a human user as either a monocular or binocular device.

Abstract: A compact, wide-field, high-resolution, low-cost and easy-to-handle head- or face-mounted image display apparatus in which unwanted light is reduced without using a polarizing member or a louver optical system.

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 system which is compact, lightweight and satisfactorily corrected for aberrations and may be suitably used as an imaging optical system or an ocular optical system for a head- or face-mounted image display apparatus which forms no intermediate image. The optical system includes an optical member (7) and a diffraction optical element (8), which are decentered with respect to each other. The optical member (7) has at least three adjacent optical surfaces, at least one of which is a curved surface. At least two reflections take place between the optical surfaces. The space between the optical surfaces is filled with a medium having a refractive index larger than 1. Light rays emitted from an image display device (6) enter the optical member (7) through a first transmitting surface (5) disposed to face the image display device (6) and are reflected by a first reflecting surface (3).

Abstract: A head-mounted image display apparatus which uses two or more image display devices, and which is compact and lightweight and yet enables observation of a clear image over the entire observation image field at a wide field angle and high resolution. The image display apparatus includes two image display devices (5 and 6) and two ocular optical systems (3 and 4) for projecting, respectively, images formed by the two image display devices (5 and 6) as enlarged virtual images in front of one common eyeball (7) of an observer and for leading the projected images to the eyeball (7). When the two ocular optical systems are defined as a first ocular optical system (3) and a second ocular optical system (4) in order from the observer side, the first and second ocular optical systems (3 and 4) have concave mirrors (12 and 22), respectively. These reflecting surfaces are tilted or decentered with respect to an observer's visual axis (2).

Abstract: A headup display including a light emission-type display source, a concave mirror having an spherical reflecting surface and located so as to reflect light emitted from the display source, and a reflection-type hologram located so as to reflect the light reflected on the concave mirror toward an observer in a mobile unit. The concave mirror is configured so that its lateral focal length contributing to lateral enlargement of a displayed image is shorter than its longitudinal focal length contributing to longitudinal enlargement of the displayed image. The reflection-type hologram is configured so that its longitudinal focal length contributing to longitudinal enlargement of the displayed image is shorter than its lateral focal length contributing to lateral enlargement of the displayed image.

Abstract: 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. The image display apparatus has an image display device (7) and an ocular optical system (8) for projecting the image of the image display device (7) and leading the projected image to an observer's eyeball (1). The ocular optical system (8) has at least three optical surfaces, and a space formed by these surfaces is filled with a medium having a refractive index larger than 1. The three optical surfaces are defined as a first surface (3), a second surface (4), and a third surface (5), respectively, in the order in which light rays pass in backward ray tracing from the observer's eyeball (1) to the image display device (7).

Abstract: A head mounted display for use in virtual reality applications and typically in the form of a slim visor is provided with binocular magnifying optics which permit the binocular viewing of an image displayed by a single miniature LCD video screen magnified at infinity focus at left and right exit pupils. A vertically offset beamsplitter is provided having two elements being substantially mutually perpendicular planar semi-reflecting mirrors disposed respectively above or below the horizontal optical axis of the LCD. A single image viewed from the LCD passes through the semi-reflecting mirrors to be reflected off a concave mirror. One reflection part of the image is reflected off one of the elements and then by a right hand fold mirror towards the right hand exit pupil. Another part of the image is similarly reflected off another of the elements and left hand fold mirror towards the left hand exit pupil.

Abstract: Head up display apparatus comprises an image source for projecting an image that is to be displayed, a head up display projection unit, and a combiner for reflecting an image that is viewable. The image source projects an image that is to be displayed. The projection unit comprises a double-reflecting primary mirror that receives the image projected by the image source, and a secondary correcting mirror that receive the image reflected from the primary mirror. The secondary correcting mirror reflects the image back onto the primary mirror, and this image is reflected out of the projection unit to the combiner, which reflects the image that is displayed to a viewer. The dual-mirror, triple-reflection design of the present allows it to be smaller than equivalent designs that do not incorporate a mirror arrangement that provides for double-reflection of the projected image from the primary mirror. The projection unit essentially operates as a three-element design, but contains only two optical elements.

Abstract: A small-sized, lightweight and inexpensive visual display apparatus which enables observation of a full-color image at a wide field angle, which is clear and flat as far as the edges thereof, without using a costly element such as a polarizing element. The visual display apparatus has an image display device (4), and an ocular optical system for projecting an image formed by the image display device (4) and for leading the projected image to an observer's eyeball. The image display device (4) has a louver (10) for limiting the viewing angle. The ocular optical system has two semitransparent surfaces (2 and 3). The second semitransparent surface (3) is a curved surface which is concave toward the observer's eyeball side, so that light rays emanating from the image display device (4) first pass through the second semitransparent curved surface (3), and are reflected by the first semitransparent surface (2).

Abstract: An optical beam splitter has an imaging lens assembly with a single optical axis and reflectors located on the image side of the lens to produce a number of real images of an object imaged by the lens. The imaging lens assembly is designed to image the real image formed by a camera lens assembly on the optical axis where the camera lens assembly has an exit pupil a known distance on the object side of this real image. The imaging lens assembly is then adapted to image this exit pupil of the camera lens to an aperture plane adjacent the reflectors. The optical beam splitter is described in particular in an application in an electronic high speed camera wherein multiple images of an object are formed for high speed photography.

Abstract: A virtual image instrument panel display (20) has a display source (22) and reflective elements (24, 26). The display source (22) generates a beam (28) including an image to be viewed. The reflecting elements (24, 26) receive the beam and provide a virtual image of the image of the beam. The virtual image is focused on a viewing plane at a predetermined and substantial virtual distance away from the user to enable easy eye focus transition between the virtual image and distant objects. The folded nature of the optical system provides for a compact package suitable for installation in an automotive dashboard.

Abstract: An apparatus for displaying an image comprises a) a retroreflective screen, b) a polarising beam-splitter making an oblique angle with the screen, c) a device for projecting light from an image or object toward the screen through the beam-splitter, and d) a partially reflective light transmissive sheet being provided at an oblique angle to the beam-splitter such that the sheet may be view through the beam-splitter. The apparatus may be used as a head up display in which real and virtual images in respective positions may be viewed.

Abstract: An optical system for alternative or simultaneous direction of light from two scenes to the eye of a viewer comprising (a) a first lens having a first focal length; (b) a second lens having a second focal length, the first and second lenses being positioned aside one another in front of one of the eyes of the viewer, such that a single light beam from any of the scenes passes only through one of the first and second lenses; and (c) an optical arrangement for directing incident light originating from the first scene and passing through the first lens into the eye of the viewer, and at the same time, for directing incident light originating from the second scene and passing through the second lens into the eye of the viewer, the optical arrangement being positioned between the first and second lenses and the eye of the viewer.

Abstract: The present invention relates to an optical system apparatus, which has a first surface symmetric with respect to only one symmetry plane and a second surface symmetric with respect to only the symmetry plane, in which the first plane is a reflective, concave surface and is inclined relative to a reference axial ray present in the symmetry plane. Further, a local power of the second surface changes from a positive to a negative.

Abstract: A wide FOV imaging system (10) includes an objective lens (14), a convergent reflective element (18) positioned proximate an intermediate image (16) formed by the objective lens, and a re-imaging lens (20) for re-imaging the intermediate image. The present invention significantly improves image fidelity while minimizing optical components by utilizing a convergent reflective element proximate the intermediate image to reverse the propagation of aberrations produced by the objective lens (14) to, as a result, significantly cancel or reduce the aberrations contributed by the re-imaging lens.

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 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 image display apparatus includes an image display device and an ocular optical system for projecting an image formed by the image display device and for leading the projected image to an observer's eyeball. The ocular optical system (3) has three surfaces, and a space formed by the three surfaces is filled with a medium having a refractive index larger than 1.

Abstract: An optical guide (10, 40, 50, 60) for horizontally aligning two vertically stacked images generated by one or two SLMs. The optical guide has a channel separator (10a) that directs both images along two different paths. A pair of aligning reflectors (10b and 10c) on each path vertically shift the images with respect to each other so that at least part of the images on the first path are aligned side-by-side with at least part of the images on the second path. The channel separator (10a) then redirects the images to the image plane 15. Along both paths, at least two of the reflecting surfaces of channel separator (10a) or aligning reflectors (10b and 10c) are optically powered so as to change the width or height of the images.

Abstract: The present invention relates to an image display apparatus disposed near an observer's head for observing an image displayed on image display means as an enlarged virtual image. The apparatus has a relay optical system for causing the displayed image by the image display means to be intermediately formed, the relay optical system having at least one decentered reflecting surface for bending a light beam from the image display means, and at least one lens of an anamorphic aspherical shape differing in curvature in any orthogonal direction, and an eyepiece optical system for directing the image by the relay optical system to the observer's pupil, the eyepiece optical system having at least one decentered reflecting surface which is an anamorphic aspherical surface of a concave surface shape for bending the light beam from the relay optical system.

Abstract: A compact, virtual image electronic display system is provided for forming a compound magnified virtual image of a source object. The display system includes a microdisplay for producing the source object, a first reflective magnification optic, and a second magnification optic which, in combination with the first magnification optic, forms a compound magnified virtual image. The first and second magnification optics may be separate optics. Alternatively, a single beamsplitting magnification optic may be used as both the first and second magnification optic. When a single beamsplitting magnification optic is employed, the beamsplitting magnification optic serves as both a first, reflective magnification optic to produce a magnified virtual image and as a second, transmissive magnification optic to produce a compound magnified virtual image which is seen by the observer.

Abstract: An aviator's helmet-mounted display includes a visor/combiner module (14) which is configured for use with an essentially standard aviator's flight helmet (12). The helmet-mounted display also includes a conformal image source and relay optics (ISRO) module (30) which is removably attachable to the aviator's helmet. This ISRO module (30) projects an image inwardly from outside the visor/combiner module through a transparent window portion (44) thereof and out and inner surface (48) of an angulated transparent viewing portion (18,20) of the visor/combiner module (14). The image is focused at infinity and is partially reflected from the inner surface (48) to an eye (50) of the aviator so that the image is superimposed on the aviator's view of an outside scene viewed through the viewing portion (18,20).

Abstract: Systems for affording panoramic forward, side, rear and underneath views to operators of a wide range of transportation means for facilitating safe manoeuvering thereof. The transportation means include private vehicles, full trailers, semi-trailers, busses, aircraft, ships and the like.

Abstract: An image display apparatus comprises an image display device for emitting a light beam to display an image, and an observation optical system for guiding the light beam from the image display device to the pupil of an observer. The observation optical system has at least a concave, reflective surface and a convex, reflective surface in order from the pupil side of the observer along an optical axis of the light beam directed from the image display device to the pupil. The concave, reflective surface is located near the pupil.

Abstract: A compact, lightweight and wide-field head-mounted image display apparatus which is effectively corrected for chromatic aberration. The apparatus includes an image display device (1) for displaying an image, a concave mirror (2) provided to face the image display device (1) to project the displayed image into an eyeball pupil (E) as an enlarged image, and a half-mirror (3) disposed between the image display device (1) and the concave mirror (2). A diffraction optical element (20) having reciprocal dispersion characteristics is disposed somewhere in the optical path to correct chromatic aberration.

Abstract: A pulsed solid state laser system is disclosed which utilizes a plurality of individual laser rods which are sequentially pumped and whose beans are combined into a single interleaved output bean. The individual laser rods are pumped at an average power level which is below that for maximum output power from each rod, thereby obviating the need for refrigeration cooling. A compact optical system is disclosed which permits a constant beam size even at different pump levels and other advantages. A compact cooling system is also disclosed.

Abstract: The image source of a head up display for a motor vehicle is illuminated from a remote high intensity source using fiber optics. The HUD image source and optics are under the dash pad of the vehicle and include color LCD or color filtered image source. The image is lighted by a high intensity light source which yields a bright projected image and which generates substantial heat. The light source includes lamps in a fan-cooled heat sink located in the vehicle engine compartment, for example, and coupled to the image source by fiber optic light guides. The light guides abut the image source to uniformly light small image patterns commensurate with the light guide size, or light spreading techniques are used for larger image patterns.

Abstract: An optical system which is usable as either an ocular optical system or an imaging optical system, and which is satisfactorily corrected for both field curvature and comatic aberration for a field angle of up to about 120.degree. and for a pupil diameter of up to about 15 millimeters. The optical system includes a partial optical system (10) having a flat semitransparent surface (1) which is closer to a pupil plane (E), and a concave semitransparent surface (2) which is closer to an image plane (I). A refracting optical element (4) is disposed at the pupil plane (E) or image plane (I) side of the partial optical system (10) with an air spacing provided therebetween. Alternatively, the refracting optical element (4) may be cemented to the partial optical system (10). The refracting optical element (4) has a focal length f.sub.a which satisfies the condition of f.sub.a >0.

Abstract: The present invention eliminates the relay lens systems found in conventional helmet mounted displays (HMDs) by removing field distortions and aberrations with a contoured fiber optic faceplate placed in close proximity to a liquid crystal display (LCD) or cathode ray tube. The optical system typically consists of a spherical dielectric or holographically made collimator - combiner, a dielectric or holographically made fold mirror, and a contoured fiber optic faceplate. The fold mirror is flat, and the collimator - combiner is made by coating a spherical eye glass blank. The system is configured as a folded and tilted catadioptric projector with the novel feature being the contoured faceplate. There are no dispersive elements in the imaging assembly which means it can be completely polychromatic (full color) without the need for additional color correction optics as found in all refractive color systems.

Abstract: A display system and method for displaying an image including focusing optics to focus light from an image source, retro-reflector and beamsplitter, the image source and beamsplitter directing light toward the retro-reflector being directed via the beamsplitter for viewing and folding an optical path in the conjugate optics.

Abstract: A head-mounted vision enhancement system which provides crash survivabili weight, and center of gravity superior to the currently fielded image intensifier goggle arrangements. This is accomplished by positioning the goggle objective lens assembly and intensifier tube closer in around the head and then using an eyepiece to bring the image back around into the eye. Hypersteropsis is thus avoided by folding the intensifier objective lenses from the center of the forehead.

Abstract: An image display apparatus includes an image generator for generating first light having image information, and a beam combiner for superimposing the first light and second light which is incident upon the beam combiner from a direction different from that of the first light, and for guiding the superimposed light to a pupil of an observer. Also provided is a reflector positioned in a direction different from the incident direction of the second light on the beam combiner. The first light is incident upon the reflector via the beam combiner, and is reflected back to the beam combiner after being reflected by the reflector.