Abstract: A projection system having a rear projection screen (28) employs a collimating lens (26) in the form of a Fresnel lens adjacent the rear surface of the screen (28) to improve the image luminance at various viewing angles and provide uniform brightness over the area of the screen. A fiber optic face plate (30) or two crossed films of microlouver light control material is interposed between the collimating Fresnel lens (26) and the rear of the projection screen (28) to provide a high degree of blocking of high intensity light, such as sunlight, that may impinge upon the front of the screen. The optical fibers (42) of the fiber optic face plate have a low numerical aperture and an opaque cladding. The arrangement allows an image to be provided on the screen with high contrast even in the presence of sunlight striking the screen.

Abstract: A rear projection display apparatus for displaying an image reduces parallax error. The display apparatus includes a housing, a transparent screen support having top and bottom surfaces, a translucent display screen removably adhereable to the top surface of the screen support, and a projector to project the image onto the display screen. Optionally, a series of mirrors may be provided to sequentially reflect the image from the projector onto the display screen. In a preferred embodiment, the housing is pivotally mounted on a base, and houses the display screen, screen support, mirrors and projector.

Abstract: A continuous slide projector constructed of a box housing having a semi-transparent mirror pivotally attached to an open front frame. A light source is mounted within the housing for illuminating a transparent slide strip positioned between the light source and the semi-transparent mirror. The slide strip is coaxially rolled upon two spools, each having a drive means, so that when the spools are rotated the slide strip moves in unison with the spools. A second light source is mounted on the housing above the semi-transparent mirror such that a person in front of the housing will produce an illuminated image of himself in the mirror upon energizing the second light source.

Abstract: A multiple projection television system is comprised of a plurality of projection units stacked in matrix to form a large television screen. Each of the projection units has a cabinet, a projector provided in the cabinet, and a screen secured to a front portion of the cabinet. A mounting frame is provided in the cabinet for slidably mounting the projector in forward and rearward directions. A back of the cabinet is opened so as to allow removing of the projector from the cabinet. The screen is detachably secured to the cabinet so as to allow removing of the projector from the cabinet.

Abstract: A collapsible, large screen audiovisual display system is provided. The preferred embodiment of the invention includes a square-shaped, forwardly mounted projection screen bordered by a protective framework. The screen is connected to a rearwardly placed, square-shaped, support frame by extendable scissor arms. A flexible drape extends between the screen and rear support frame and is internally supported by a plurality of guy wires. Each guy wire is connected at a first end to a recoiling reel and at a second end to the periphery of the screen and passes through a plurality of grommets positioned on the inside of the drape. The invention is equipped with wheels to aid in setup and transportation, the wheels being affixed to telescoping screw lifters such that the height of the screen and rear support frame is variable. A video projector and sound system are housed within the rear support frame.

Abstract: A projector comprising liquid crystal display panels and a projection lens for projecting the modulated light to a screen. A back surface reflection mirror including a transparent plastic sheet and a reflecting film is arranged between the projection lens and the screen. The mirror is thin and light and may have optical anisotropy. In order to eliminate an uneven pattern appearing in the screen caused by optical isotropy of the mirror and the difference between the light distribution characteristics in the screen for P- and S-polarized light, the projection lens and the back surface reflection mirror are arranged in such a relationship that a wave normal vector of an arbitrary component of the light projected by the projection lens and made incident to the back surface reflection mirror is not parallel to the optical axis of the plastic sheet.

Abstract: A compact illuminating apparatus for viewing films by transmitted light and having uniform light distribution across a diffusing plate, comprising a shallow elongated box-like main body having a base with a bottom having alternately arranged mountains and valleys walls or side parts of the box adapted to hold said diffusing plate; a frame arranged to close the box like base; a reflecting member having reflectance higher than that of said base and arranged on said bottom of said base; and an illuminating member comprising (1) light sources disposed below said diffusing plate, and (2) light-source-control member connected electrically with said light sources for controlling the operation thereof.

Abstract: A novel type projection TV has a large size fluorescent screen bearing three kinds of dots or stripes of fluorescent material which emits visible lights of red, green and blue at excitation by UV-rays, which are emitted from UV-emitting CRTs' for red, green and blue pixel of image, respectively; and a mask having UV-light passing apertures or a lens array is disposed on light paths of the UV-rays to improve color purity,

Abstract: A rear projection monitor having a housing with reduced depth is disclosed. Images produced by liquid crystal active matrices are illuminated by a light source. The images are enlarged and projected by a projection lens having a large rear focus. A mirror reflects the projected images onto a viewing screen. The mirror is positioned between 36.degree. and 45.degree. in relation to the viewing screen. The back of the housing is adjacent to and slopes at the same angle as the mirror. The depth of the projection monitor is between 33% to 41% of the diameter of the viewing screen.

Abstract: A collapsible, large screen audiovisual display system is provided. The preferred embodiment of the invention includes a square-shaped, forwardly mounted projection screen bordered by a protective framework. The screen is connected to a rearwardly placed, square-shaped, support frame by four removable horizontal support members, each having first and second ends. The support members are each connected at their first ends to a corner of the screen's protective framework and at their second ends to the corresponding corners of the rear support frame. A flexible drape extends between the screen and rear support frame and is internally supported by a plurality of support ribs. A plurality of spaced loops attached the drape to the four horizontal support members. The invention is equipped with wheels to aid in setup and transportation and includes audio speakers mounted beneath the screen. A video projector and sound system is housed within a projector rack adapted to connect to the rear support frame.

Abstract: A multiplanar image display system having a plurality of display units disposed to expose, by transmission through and reflection by transparent panels, displayed images to a viewing end of an image chamber. The images overlap along a common viewing axis to create an illusion of a three-dimensional display. The transparent panels and a primary display unit are disposed along, and secondary display units are displaced from, the viewing axis. The transparent panels and the display units are angled to each other and to the viewing axis. The display units are adjustably mounted; and the distances separating the overlapping images, and thereby the amount of parallax, are controllable as a function of the distances between the display units and their associated reflecting transparent panels.

Abstract: A rear projection television set is disclosed which includes a screen assembly, a reflector mirror located behind the screen assembly, and a projection source having a lens system for projecting rays of light to a rear side of the screen assembly through the reflector mirror. The projection source is arranged below the reflector mirror. A ray of light emitted along an optical axis of the lens system of the projection source is reflected by the reflector mirror. A positional relationship among the screen assembly, the projection source and the reflector mirror is determined so that the reflected ray of light is incidental from an upper side to a lower side relative to the screen.

Abstract: The present invention permits easy and safe replacement of a lamp, improves stability of a video projector, and provides a compact and lightweight video projector.A projector driving battery is mounted in a battery mounting section formed in the bottom of a cabinet of a video projector. Therefore, the heavy battery is located in tile bottom of the cabinet. This further stabilizes the video projector. A lamp unit is mounted on a lamp mounting section formed in the back of the cabinet. When the lamp unit is mounted, a power output terminal in the cabinet is connected with a power input terminal of tile lamp unit at the same time. Thereby, when a lamp is replaced, it is unnecessary, unlike conventionally, to open and close a cover or electrically couple the lamp. Specifically, lamps can be changed merely by dismounting and mounting lamp units. Furthermore, a spare lamp unit 20 can be used as a lens cap.

Abstract: A projection television system which adapts automatically between from screen projection and rear screen projection upon insertion of the projector into a rear screen cabinet. A compact projection unit has a quick-disconnect electric connector and optical aligner which mate with connection elements in a projection cabinet upon insertion of the projector into an opening in the front of the cabinet. The cabinet has a two-mirror optical relay which inverts the projected picture. Upon completion of insertion, the electric connections automatically invert the image being projected by the projector. In another embodiment, insertion also automatically connects to audio equipment in the rear screen cabinet.

Abstract: A liquid crystal projector is obliquely disposed in a lower front portion of a cabinet. A first mirror for reflecting light beams of R, G and B coming from the liquid crystal projector is disposed obliquely with respect to the top-bottom, right-left and front-rear directions of the cabinet. A second mirror is disposed so as to be inclined toward a screen. With this configuration, the optical axis of the light beams that extends from the liquid crystal projector to the screen is folded back three-dimensionally. In the liquid crystal projector, the optical axis of a condensing reflector may be slightly inclined from the central axis of a projection lens.

Abstract: Disclosed is a liquid crystal display unit comprising liquid twisted nematic liquid crystal material sandwiched between two polarizers. Transparent electrodes are provided on each side of the layer of liquid crystal for locally energizing liquid crystal material in the vicinity of two energized transparent electrodes. Polarized light passing through one polarizer is twisted or not twisted depending upon the energization state of the liquid crystal material and depending upon the second polarizer orientation does or does not pass therethrough. Accordingly, depending upon energization locations, images are formed which can be projected upon a screen. In preferred embodiments the liquid crystal display unit is used in conjunction with a cabinet to provide a low stress work station. A further embodiment includes a folded optical path in combination with the liquid crystal display so as to provide a compact projector.

Abstract: A slide projector which is suitable for both wall projection and ground-glass plate projection has a displacement means carrying a deflection mirror system and a ground-glass plate. The displacement means is movable between a collapsed condition in which the displacement means with mirror system and ground-glass plate is in a compact configuration in a housing compartment beneath the projector, for wall projection purposes, and a deployed condition for ground-glass plate projection purposes, in which the displacement means is moved out of the housing compartment into a position in which the mirror system and the ground-glass plate are in front of the lens system of the projector.

Abstract: Disclosed is a liquid crystal display unit comprising liquid twisted nematic liquid crystal material sandwiched between two polarizers. Transparent electrodes are provided on each side of the layer of liquid crystal for locally energizing liquid crystal material in the vicinity of two energized transparent electrodes. Polarized light passing through one polarizer is twisted or not twisted depending upon the energization state of the liquid crystal material and depending upon the second polarizer orientation does or does not pass therethrough. Accordingly, depending upon energization locations, images are formed which can be projected upon a screen. In preferred embodiments the liquid crystal display unit is used in conjunction with a cabinet to provide a low stress work station. A further embodiment includes a folded optical path in combination with the liquid crystal display so as to provide a compact projector.

Abstract: A projector suitable for a rear projection type receiver is disclosed. The projector has a device for generating an image and an image projecting device for projecting the image to a screen. The image projecting device includes a projection lens system and a reflector. The projection lens system directs the light flux indicative of the image from the image generating device toward the reflector so as to be away from the screen. The reflector bends the light flux and directs the light flux from the reflector to the screen along a predetermined path. The image generating device and the projection lens system are arranged on the side of the predetermined path along the path.

Abstract: A display apparatus comprises a projecting device for projecting an image, with the projecting device having a projection optical system having a limited pupil diameter and screen device arranged at a position where an image is substantially projected by the projecting device. The screen device has at least two sheets in each of which a number of prisms extending like a straight line or a curve are formed on the surface on the side opposite to the projecting device.

Abstract: On the outside of a body of a projector, an LCD is provided for displaying an image. A lamp is incorporated in the projector body for illuminating from the rear an image displayed on the LCD. A movable member is provided on the outside of the projector body for vertical swinging movement between open and closed states, and, in the closed state, allows the LCD to be directly observed. A projecting head is provided on the movable member for projecting, in the open state, the image illuminated by the lamp onto a screen outside the projector body.

Abstract: A microfilm map reader is provided and consists of a housing removably attachable to a sun visor of a motor vehicle. A collapsible microfilm slide projector is built into the housing and has an translucent screen. A microfilm slide with a map thereon is insertable into the projector so that a person within the motor vehicle can read the map on the slide that is projected and enlarged onto the translucent screen.

Abstract: A figure is disclosed having a head with a back projected image to animate the facial expression of the figure. The image is back projected onto the head's face by a wide angle lens inside the head having an extremely short focal length. The lens is adjustable for focusing and image registration purposes in vertical, horizontal and lateral directions with respect to the face by a lens adjustment system also inside the head. The image is brought inside the head to the lens by a coherent fiber optic bundle having a high resolution which transfers the image from a remote image source, such as a motion picture projector. Independent movement of the head in all directions with respect to other parts of the figure is provided by a motion device. The lens adjustment system and fiber optic bundle ensure that the image always remains in proper focus and registration on the face despite free and unrestricted movement of the head by the motion device.

Abstract: An image projecting system for irradiating a microfilm with light emitted from a light source and projecting an image recorded on the microfilm onto an image receptor such as a screen or a photosensitive drum, the image projecting system having a masking unit which is mounted in the body of the system removably. The masking unit contains a first masking portion which is for changing the range of the image advancing toward the image receptor through an optical path, in a first direction of the microfilm, and a second masking portion which is for changing the range of the image in a direction approximately perpendicular to the said first direction. These masking portions are disposed in close proximity to the microfilm. Thus, a desired range of the image recorded on the microfilm can be projected on the image receptor and the outer peripheral edge of the projected image is made sharp and clear by the above masking portions.

Abstract: The volume of the housing of a rear-projection system can be reduced by 20 to 25% when the light beam is obliquely incident on the projection screen. The obliquely incident light beam is deflected towards the viewing space by means of a prism plate (731). By dividing the light-refracting action of the prism plate between the front and rear of the plate only minor light loss occurs.

Abstract: The present invention relates to a projection type display device wherein images based on light projected form a projection source are formed on a screen. The screen is composed of two Fresnel sheets and one lenticular sheet so that the display device can be monitored at a short distance, more specifically at a short distance within about twice the height of the screen. The light from the projection source is converged at the short distance. The lenticular sheet diffuses the light in the horizontal direction.

Abstract: An apparatus and a method for displaying visual information such as music to persons having visual deficiencies includes a housing having a rear projection screen and a mechanism for projecting images of the information. The mechanism can include a slide tray for storing transparencies of the information, a projection lamp and lens, and means for moving the slides from the storage tray to the projection lamp and back again. Controls are provided for varying the brightness of the projection lamp and the speed at which the slides are displayed in a predetermined sequence. Also, the size of the image on the viewing screen can be varied. In a manual mode of operation, a foot switch is available for sequencing the slides and both forward and reverse directions of display are available.

Abstract: A screen-forming sphere is made of a front translucent half-sphere and of a rear half-sphere which is opaque except in a central region. An image projector is situated behind the screen and has a front face comprising a platen mounted in front of the optic of the image projector. The platen contains a rotary polarization filter rotated by a first motor. The filter is occultable by a rotary flap mounted on spindles rigidly connected to two rotary vertically aligned disc members which rotate in synchronism under action of a second motor.

Abstract: A projection and viewing apparatus having a hollow housing with an open top and front and back walls is also provided with an optical system carriage which is mounted within the housing for rotational movement with respect to the housing. This carriage is capable of rotation from an upright position to a substantially horizontal position. The carriage is composed of a lower portion which is mounted to the housing for the rotational movement and an upper portion which is pivotally mounted with respect to the lower portion so as to be able to move from an extended position in which the upper and lower positions define the operational carriage, to a retracted position in which either the upper or lower portion is withdrawn into the other. Provision is made for locking the upper and lower portions together in the extended position. The lower carriage portion is provided with a depth dimension which is no greater than the distance between the front and rear walls of the housing.

Abstract: A portable microform reader 10 comprising a foldable frame 12. The frame includes a view screen 14 and a microform holder 18. A microform 38 is illuminated by a light package 80 and an image of a portion of the microform 38 is projected through pick up lens 48. A fiber optic cable 22 carries the image from the objective lens 48 to a focusing lens 52 which projects a magnified image onto the view screen 14. Pickup lens assembly 20 is moved manually to view different areas of the microform.

Abstract: The present invention consists in a rear image projection apparatus having a transmissive screen of high efficiency and low moire disturbance. In particular, the screen comprises a Fresnel sheet having a Fresnel lens, a front sheet having a horizontally-diffusing lenticular lens and a light diffusing element, and if necessary, a third sheet, wherein at least one surface of the Fresnel sheet or the third sheet is formed with a vertically-diffusing lenticular lens, and a pitch of the Fresnel lens is set to be at most 150% of an effective diffusion width of the diffusion element.

Abstract: The invention pertains to a large tunnel enclosure including a main cylindrical corridor and a conveyor-belt-driven bottom floor. The main corridor comprises an inner wall being almost totally constituted by a plurality of adjacent image-producing screens, of translucent nature. The main corridor may be closed at each end thereof by extendable doors. The doors and the walls of the corridor comprise therewithin cameras which project images onto the inner side of the screens. The corridor is of modular construction, such that it may be dismantled in sub-units for facilitating transportation thereof.

Abstract: A microform viewer has a case section pivotally mounting a screen, to move from a collapsed position to a viewing position, and slidably receiving a two-part projection section that telescopes into the case section. As the projection section moves into and out of the case section it positively drives the screen between collapsed and display positions. The projection section is made of two mutually separable housings that fit together along the film path so that when the two housings are separated the two pressure plates forming part of the film path are readily accessible.

Abstract: A video exhibit stand and method of exhibiting informational programs comprises a housing having a plurality of large and small openings therein and arranged around the periphery thereof. A plurality of cathode ray tubes and audio speakers are supported within the housing with the screens of the cathode ray tubes secured within the large openings and the audio speakers secured within the small openings. Video transmitter means within the housing conducts informational programs recorded on cassette tapes to a four-way signal splitter which splits the video signal into four distinct but identical signals. These signals are conducted to the inputs of the cathode ray tubes and the audio signals are conducted to the audio speakers. The exhibit stand is portable and may be located at the juncture of hallways where people may view the cathode ray screens from all directions. A plurality of such video stands may be located at remote points in a large auditorium room or in separate remote rooms.

Abstract: An apparatus is provided for receiving the inverted video image of a television set and for enlarging and projecting this image onto a suitable display surface. An adjustable concave mirror, located at a distance from the television set which is dependent upon the size of the enlarged image which is desired, is enclosed in a housing which shields the projected image from being washed out. The housing has a non-reflecting black matte interior finish and an opening through which the image is projected towards the display surface.

Abstract: An image focusing apparatus for microfiche film readers and other optical systems has a lens holding apparatus which rests on a transparent or glass plate, a rotatable lens adjusting assembly in the lens holding apparatus, a shaft slidably and pivotally connected to the lens adjusting assembly, a knob on the shaft, and a shaft holder which fixes the position of the shaft with respect to the reader. The lens holding apparatus is universally mounted to the frame of the reader to enable the lens holding apparatus to move freely in response to changes in the angular disposition of the glass plate with respect to the horizontal plane. The lens adjusting assembly has an eccentric finger which translates the rotating motion of the knob and shaft into a vertical force, which moves the lens. The lens adjusting assembly has a barrel, a socket in the barrel and key slots along the socket. The shaft has a partially-spherical end and keys which slidably and pivotally fit into the socket and key slots.

Abstract: An optical display device for creating the illusion of an object floating in space comprises a lens means having the optical properties of a convex lens, a housing for supporting the lens and an object such that the light path from the object to the lens is greater than the focal length of the lens and means for illuminating the object.

Abstract: A projector into which are placed slides having various cooking recipes imprinted thereupon, and the invention including a screen, upon which the recipe is projected greatly enlarged, so that a homemaker can more easily see the enlarged text, while making a food preparation.

Abstract: A microfilm projector installed in the dashboard or instrument panel of a vehicle such as an automobile, a boat, an aircraft, and the like, comprising a rear projection screen mounted in a cut-out portion of the dashboard or instrument panel, a projection lens system and an illumination device for projecting on the rear surface of the screen an enlarged image of information photographically recorded in a transparency card made of a length of microfilm sandwiched between a pair of laminated transparent carriers. The information data transparency card is introduced through a slot in the top of the dashboard or instrument panel and is gravity fed in a chute to an aperture window disposed between the illuminating and lens projecting systems. Controls are provided for turning on and off the illuminating lamp, for stopping and indexing the transparency card at the aperture window, and for dropping the card, after use, into an appropriate receptacle disposed below the chute.

Abstract: Apparatus for supporting a television receiver housing and projecting an image from the face of the picture tube to a remote, reflective screen having dimensions significantly larger than the picture tube. The apparatus includes a base providing an inclined support surface for the TV housing with an adjustable stop member for engagement with the lower, rear edge of the housing to establish the fore and aft position thereof on the support surface. The apparatus further includes a hood defining an enclosed path between an opening at one end for encircling the face of the picture tube of a TV supported on the base, and an opening at the opposite end in which the lens barrel of the projection lens system is frictionally engaged for unitary focusing movement. The TV set and the lens remain physically unattached to any elements of the projection system. The invention is also directed to novel features of the hood, per se.

Abstract: A selective Real Estate Display System including an enclosure which may be provided within a real estate office or in a separate structure adjacent to a real estate office, a slide projector, in the enclosure, provided with a substantial number of slides comprised of a sequential arrangement of group of slides, the picture images on the slides of each group dealing with a particular real estate category such as three bedroom, two bath homes, etc. A rear projection screen mounted in a wall of the enclosure is directed toward a parking area for viewing by the occupants of a vehicle in the area, and a selector box on a post, positioned adjacent to the parking area, includes a plurality of push buttons, one for each category of real estate, for selective operation by a vehicle occupants while seated in the vehicle. A voice commentary from a multi-cartridge tapedeck is projected from a speaker atop the selector box.

Abstract: A rear projection viewer apparatus of the type wherein the projected images are initially projected downward towards a mirror mounted in the base of the viewer which redirects the projected images upwardly and forwardly to a viewing screen forming the front of the viewer. Means are provided for removing the mirror element from the downward path of the projected images and an auxiliary viewing screen smaller than the primary screen is disposed in the base of the viewer to receive the projected images thereupon thereby permitting viewing of the images on the smaller screen when the viewer is positioned with its primary viewing screen facing downward.

Abstract: A rear projection viewer apparatus of the type wherein a projected image is projected towards a primary viewing screen which when in its operative viewing position forms the front of the viewer, the front viewing screen being attached to other portions of the viewer housing so that it may be moved to an inoperative position. A second rear projection screen substantially smaller than the first screen is mounted within the viewer housing in a manner where it may be moved from an inoperative position where it does not interfere with projecting to the primary viewing screen to an operative position wherein the images may be projected upon the rear thereof. Means are provided for automatically moving the small auxiliary screen from its inoperative position to its operative position in response to manual displacement of the primary viewing screen from its operative position to its inoperative position.

Abstract: A portable microform reader is provided with a microform carrier and a projection system for projecting an enlarged real image of the information carried on a portion of the microform onto a viewing screen. A binocular magnifying system is arranged for viewing the screen and for further enlarging the image thereon to produce a virtual image of acceptable reading size. The projection system comprises a source of illumination, a condenser lens, and a projection lens for projecting an image of the information carried on the microform onto the screen. The magnifying system may consist of appropriate binocular lenses where such lenses, in combination with prismatic converging means, produce the desired magnification. Beam splitting means may alternately be provided to eliminate the need for prismatic converging means, and a mirror arrangement may be provided to "fold" the projected beams for further limiting the size of the reader.

Abstract: The disclosure relates to a microform reader apparatus of the type which projects a magnified image of an image film frame onto the rear side of a viewing screen to facilitate forward viewing of the magnified image. The microform reader of the present invention includes an adjustable mirror assembly positioned between a light source and condensing lens for optimizing the brightness of the displayed image. In a preferred form the mirror assembly is adjustable from the front of the microform reader to allow simultaneous monitoring of the brightness of the display while the adjustment is being made. The microform reader of the present invention also includes an adjustable lens assembly which allows the optical axis of the lens assembly to be adjusted for perpendicularity to the image frame surface.

Abstract: A portable holographic information retrieval system is described in which individual holograms each of which contains the alphanumeric information from an individual page of a book, are reconstructed on a rear-illuminated viewing screen. The individual holograms are contained on a permanent transparency as a matrix, the holograms of successive pages of a book being arranged in a sequential manner. The entire matrix of individual page holograms is contained on a transparency which is approximately equal in size to a standard 35 millimeter photographic slide. The reconstruction apparatus has the rear-illuminated viewing screen collapsibly mounted to a system housing. The housing includes a small source of a collimated beam of light for illuminating a selected "page" in the transparency.

Abstract: A system for providing a standard microfiche or similar reader with the capacity for making prints of the projected material without substantially modifying the reader is disclosed. A screen extension is provided having one end mountable to the face of the reader. The viewing screen of the reader is removed from its normal position and placed at the opposite end of the screen extension. The extension has a substantially light-impervious walled periphery which has an elongate narrow slot in one wall. A paper carrier is insertable through the slot in the periphery of the screen extension to a position adjacent the interior surface of the viewing screen. One side of the paper carrier is removable to expose light-sensitive paper in the carrier to the image projected by the reader. The system of the present invention also includes apparatus for supplying light-sensitive paper to the paper carrier and apparatus for developing the exposed light-sensitive paper.

Abstract: A dental light reflector and visual-audio analgesic assembly having a housing including a display screen upon which a selected film is projected and/or displayed. A reflector device is mounted below the housing, and includes a reflector and interacting lamp to illuminate the area of the patient's mouth under operation by the dentist or dental assistant. The positioning of the reflector assembly with respect to the housing during normal dental procedures is such that the display screen is placed into the direct field of view of the patient without any light interference from the reflector. The film being displayed may include a soundtrack and earphones enabling the patient to listen to the soundtrack of the film. Storage means are provided along the top plate of the housing to store films for selection by the patient.

Abstract: The present invention consists in a rear image projection apparatus having a transmissive screen of high efficiency and low moire disturbance. In particular, the screen comprises a Fresnel sheet having a Fresnel lens, a front sheet having a horizontally-diffusing lenticular lens and a light diffusing element, and if necessary, a third sheet, wherein at least one surface of the Fresnel sheet or the third sheet is formed with a vertically-diffusing lenticular lens, and a pitch of the Fresnel lens is set to be at most 150% of an effective diffusion width of the diffusion element.