Abstract: A projection type display device including an image pickup device is provided. A projection mirror of an OHP is made a half mirror 108, so that a picture having transmitted through the half mirror can be taken in by an image sensor 102.

Abstract: An overhead projector provides an unobstructed view of projected images by minimizing the vertical dimension of the projector and provides sufficient brightness of projected images by minimizing the loss of light. The light emitted from a light source housed in the body of the projector is reflected by a first reflection mirror and directed, through a transparent stage on which a transparent original is placed, to a second reflection mirror. Meanwhile, on the transparent stage, the principal ray axis of the light beam forms an angle .theta. with respect to the center axis of the surface of the transparent original. After reaching the second reflection mirror and being reflected thereby, the light is condensed into a projection lens unit, and is projected therefrom onto a screen to form thereon an image of the transparent original.

Abstract: A portable overhead projector includes a projection unit having a light source and a projection lens, a stage having a Fresnel lens which has a reflecting surface facing the projection unit, and an arm part for connecting the projection unit with the stage. The arm is sized to accommodate the projection unit and the stage when these are folded thereinto. The size of the projector when the projection unit and the stage are folded into the arm part is not substantially larger than approximately a length of 184 mm, a width of 135 mm, and a thickness of 58 mm. Since each member can be folded, it is possible to make the portable overhead projector compact so that users can conveniently carry such an overhead projector in their bags.

Abstract: An electronic calculating apparatus for use with an overhead projector and a projection screen includes an electronic calculator and a display device. The electronic calculator comprises a data input unit and a data sending unit. The electronic calculator performs an operation corresponding to data inputted from the data input unit, and displays a result of the performed operation. The display device comprises a liquid crystal display unit of a transparent type and a data receiving unit for receiving data sent from the sending unit of the electronic calculator. The display device is placed on the top of the overhead projector, and, upon receipt of the data sent from the data sending unit of the electronic calculator, the display device performs an operation that is substantially the same as the operation performed by the electronic calculator, and displays the result of the performed operation on the liquid crystal display unit of a transparent type.

Abstract: A liquid crystal display with projecting function including an open-top box body with enclosed sides, a projection light source, a condensing lens, a liquid crystal display plate, a relay plate, a reflective lens and a back light plate. The projection light source is disposed at the bottom side of the box body. The condensing lens is disposed in the box body above the projection light source. The liquid crystal display plate has one side connected to a display light source and the other side connected to the box body. The reflective lens is secured below the relay plate. The back light plate is secured above the relay plate. The relay plate, reflective lens and the back light plate may be closed and accommodated in the box body between the liquid crystal display plate and the condensing lens for displaying purposes. They may also be obliquely disposed on the upper side of the liquid crystal display plate for projection purposes.

Abstract: A projector which projects a flat picture or image in a horizintal plane onto a vertical screen. Because the projection optic used is arranged above one corner of a four cornered picture and can be rotated about a vertical axis the projector can be placed not only on one side of the projected picture, which is thus not obstructed by the projector and it's operator, but alternatively to the either side thereof. The picture can be square or rectangular. The invention can be applied both with overhead projectors and with TV type projectors.

Abstract: An overhead projector includes a housing including a stage which is formed in its top wall and on which a transparency bearing an image to be projected is placed and an air outlet formed in one of its two side walls, an exhaust fan incorporated in the housing for exhausting air in the housing through the air outlet of the housing, a projection light source such as a high illuminance halogen lamp disposed in the housing for illuminating the transparency on the stage from inside the housing, a projection head mounted for projecting a magnified image from the transparency on a screen and including a focusing lens and a reflecting mirror, a column mounted on the housing to hold the projection head over the stage, a Fresnel lens disposed inside the stage to converge light from the light source on the focusing lens of the projection head, a cooling fan, and air guides for guiding air delivered from the cooling fan so that the air flows along a surface of the stage.

Abstract: A ring binder holder for transparency sheets comprises an elongated, rectangular ring-engagable strip of sheet material such as plastic or heavy paper having two parallel longitudinal edges. A line of ring-engagable openings in the strip is parallel and adjacent to one of the edges. Along the other edge is a line of adhesive on the strip that is adapted to adhere and attach the strip to an edge of a plastic transparency sheet. An elongated opaque flap is hingedly attached to the strip along a line that extends the entire length of the strip between and parallel to the line of ring-engagable openings and the line of adhesive. The flap is hingedly movable between a closed position covering the adhesive line and an open position covering the ring-engagable openings and the adjacent edge of the strip.

Abstract: An overhead projector for use with a flat panel display assembly. The specialized overhead projector provides cooling for the LCD flat panel when used in an overhead projection configuration. The projector contains a rail on which the flat panel display is positioned for alignment and to provide air passage there through for cooling. A clamping mechanism is also described for securing the flat panel display to the projector. The flat panel display is a back-lit flat panel display subsystem for direct viewing as a monitor and also has overhead projection capability. The display subsystem contains a removable door assembly which provides for back-lighting for direct viewing. When the door assembly is removed, the active matrix LCD is semi-transparent and can be placed over the imaging screen of the overhead projector such that the LCD color image can be thus projected.

Abstract: An electronic timing device has a transparent liquid crystal display for use on an overhead projector, for projecting a large image of the LCD numerals on a screen or wall of a classroom, for timing of tests or other activities. The timer has a plastic casing, various function keys, a solar cell and/or battery, other internal electronics and a transparent liquid crystal display. Foldable legs of the timer, when open, maintain the timer a set distance above the light stage of the projector so as to prevent the LCD from overheating. One of the foldable legs, in the closed position, serves as protection and as a reflective backing for the LCD, so that the timer can function as a desk top LCD clock in the closed position. The timing device can function as a clock or timer in various modes.

Abstract: A reusable presentation frame for overhead transparencies that has a view window through which a transparency may be revealed. The presentation frame has a "track" through which an opaque sliding concealment (slider) means may slide and thus conceal a variable portion of the transparency. The presentation frame may be constructed by bonding together multiple levels each having a plurality of borders which define the view window. Starting at the bottom level, the levels may include at least one raiser level, a transparency entrance level through which an overhead transparency may be inserted, a first ledge level, a first track level, and a top frame. The opaque slider may be inserted through the first track level at a side without a border and movably positioned within the presentation frame. Alternate embodiments of the presentation frame may include additional sliders and additional tracks.

Abstract: In an image projecting device for optically projecting the image of a document onto a screen, a film responsive to light is capable of changing, when illuminated, its state for selectively transmitting or diffusing incident light. More than one mirrors are provided for reflecting a reflection from a document image. A focusing lens focuses light reflected from the more than one mirrors onto the film to thereby transfer the document image to the film. A light source illuminates the film in which he document image is formed. A projecting unit projects, in an enlarged scale, light issuing from the light source and being transmitted through the film.

Abstract: A reflection prevention film coats a backside of a stage glass by a vacuum evaporation and coating, etc. A light from a metal halide lamp is not reflected on the back of the stage glass by the reflection preventing film, and is transmitted through the stage glass and is reflected on a surface of the stage glass and a transparent manuscript. The light reflected on the surface of the stage glass and the transparent manuscript enters a projection lens unit and appears as a spot light on a screen, but because the light is not reflected on the backside of the stage glass, so that the amount of the light, which causes the spot light, can be reduced. As a result, the spot light on the screen is inconspicuous.

Abstract: An overhead projector for projecting an image of a sheet material placed on a flat stage onto a remote screen standing almost vertically has a projection optical system with its optical axis aligned with a normal line of the stage. The projection optical system is shifted keeping the optical axis in parallel with the normal line so as to project an image at an angle of elevation onto the screen.

Abstract: An electronic transparency device is provided with a memory in which a plurality of frames of video data ("slides") can be stored. The apparatus includes a control microprocessor which can cause predefined sequences of slides to be presented on the LCD panel automatically. These slide "shows" are defined by the user using a hand held remote control unit in conjuntion with menus displayed on the LCD panel in window fashion by the microprocessor. The user can specify the duration that each slide in a sequence is to be shown, the video transition by which it is to be introduced, the degree of "windowshading" with which it is to be displayed, etc. Once a show is defined, it can be instituted and controlled from the remote control unit. Among other numerous features, the transparency also includes a pointer that can be superimposed on the display and controlled by the remote control unit. This pointer can be used to define certain portions of the screen that are to be displayed in highlighted fashion.

Abstract: A projection system is described which efficiently combines the output from multiple lamps, images of which are focused to a common point. The projected screen brightness is multiplied over that of a conventional single lamp of equivalent wattage. The screen brightness can be increased or diminished by switching individual lamps on or off, adjusting the light level for conventional overhead transparencies, or low transmission liquid crystal display projection panels.

Abstract: A protector adapted to accommodate a transparency to maintain it in a clean, dust-free and dry condition so that it may be used with an overhead optical projector to cast the image carried by the transparency onto a viewing screen. The protector is constituted by an open-ended rectangular sleeve whose dimensions are appropriate to those of the transparency, the sleeve including a front panel formed of transparent, acetate film that is breathable to permit a transparency inserted in the sleeve in a wet state to dry out. Also included is a rear panel formed of a transparent, synthetic plastic film of high strength having the same length as the front panel and joined thereto at one side edge to form a folder to receive the transparency so that it is then sandwiched between the panels.

Abstract: A dual mode projection system 30 includes a standard field emission device (FED) display panel 44 within a projector base 32. In this way, the light source of a standard overhead projector is replaced by FED panel 44. FED panel 44 is positioned within projector base 32 such that the viewing surface of panel 44 is substantially flush with the top surface of projector base 32. Thus, in a first mode of this dual mode projection system 30, FED panel 44 provides the light source for projecting an image of graphics 48 printed on transparency 46 onto another surface such as a projection screen or wall. FED panel 44 is coupled via connector 36 in projector base 32 and signal cable 38 to host system 40. Host system 40 may comprise the processing unit of a standard notebook computer including a keyboard 42 for data entry. Display information created by the electronics in host system 40 is transmitted through cable 38 to FED display 44.

Abstract: An improved overhead projector which allows for automated feeding of transparencies from input and output trays positioned within a body of the projector. The feed mechanism is reversible to allow previously viewed transparencies to be repositioned over a light source on a table of the projector and seen on a display screen. The transparency trays include retractable mechanisms allowing them to be switched from receiving or delivering transparencies into a feed path. An optical projection head includes an adjustable mechanism to automatically reorient a projected image for transparencies in landscape or portrait views. The adjustable mechanism includes a first mirror which is adjustable to reflect light transmitted from the light source directly from the transparency toward the display screen, or to present a thin vertical profile allowing a light image to reflect off second and third mirrors before reflecting again off the first mirror and toward the display screen.

Abstract: An armless transparency projector comprises: a projector main body having an opening; a light source lamp installed inside the projector main body for emitting light needed to project a picture on a distant screen; a Fresnel lens tilted at an angle as to catch the light from the light source, and installed inside the projector main body for holding a transparency; an image reflecting mirror installed inside the projector main body for reflecting the converging light from the Fresnel lens; and a projector lens installed inside the projector main body for projecting the image converged through the aperture of the projector lens along the light axis, to the distant screen.

Abstract: An overhead projector includes an opening in its bottom to accommodate a pivoting mirror. This opening is closed by two doors which pivot to support the projector in use. The projector includes latches which retain the doors in the closed position and gravity cams which retain the doors in the open position, but which automatically release the doors when the projector is placed on its side.

Abstract: A folding, portable overhead projector includes a thin stage body housing a fresnel lens on its top surface. The stage body is thicker on one side to form a lamp enclosure. A hinged mirror is provided within the stage body below the fresnel lens and a hinged lamp socket is provided within the lamp enclosure. Two pairs of folding legs are hingedly coupled to the stage body and the lamp enclosure and fold out from under the projector to lower the mirror and lamp and form a collapsible base for the projector. When unfolded, the legs tilt the lamp and the mirror so that light from the lamp is reflected by the mirror up through the fresnel lens on the stage. A collapsible bellows, a light baffle, and the mirror provide a substantially light and airtight enclosure for the lamp and mirror. Additional pairs of folding legs provide balance for the projector.

Abstract: In an image projector and an image forming apparatus for image projection, after a document has been laid on a glass platen, a voltage is applied from a power source to transparent electrodes respectively formed on the upper and lower surfaces of a combined polymer and liquid crystal film. As a scanner scans the document, the resulting reflection from the document scans the film. As a result, an image matching the document in tonality is formed in the film in the form of a transmittance distribution and in the original scale. After the document has been removed from the glass platen, a lamp included in an illumination unit is turned on to project the image held in the film onto a screen in an enlarged scale via mirrors and a lens which are included in a projection unit.

Abstract: A hand-held calculator has a transparent window carrying a liquid crystal display as well as transparent number and function key locations such that when placed on an overhead projector, the calculator can be used to demonstrate to a classroom of students all operations performed in a sequence of mathematical operations. The plastic casing of the calculator has one or more small holes passing through the casing at corners, so that a string or line can be used to tether the calculator to the overhead projector, preventing damage to the calculator from a fall to the floor. A further feature of the calculator is a protrusion or foot at each corner of the back of the calculator casing, for holding the back surface of the calculator slightly above the light platform of the overhead projector, for cooling of the liquid crystal display by air passing between the light table and calculator.

Abstract: A family of condenser lenses for an overhead projector (OHP) are designed to balance overall brightness in the projected image versus uniformity of illumination. The lenses are plano-convex and aspheric, and their conic constant is a function of the radius of curvature. The radius of curvature is further selected from a range which depends upon the size of the stage of the OHP. Preferred values of other parameters of the lens and OHP optical system are selected to complement the lens design. The lens is constructed of a heat-resistant material, such as borosilicate, to withstand the high temperatures generated by the incandescent lamp within the OHP base. Condenser lenses which are members of the described family provide performance, in terms of total luminous flux and uniformity of that flux, which is superior to the performance of previous designs.

Abstract: A mounting for the projection head of an overhead projector allows the head to pivot through an arc of 90.degree. between a position for operation and a position for transportation. A position lock secures the projection head in either of the two positions.

Abstract: A portable overhead projector comprising a rigid housing, a collapsible expansion housing, a fold mirror, a fresnel lens, a light source and a projecting head assembly. In the portable configuration of the projector, all of the operational elements of the projector are collapsed into the confines of the rigid housing. The expansion housing is a box-like assembly having two fixed and two hinged sidewalls. The first and second sidewalls are integrally formed with a bottom wall of the expansion housing. The bottom edges of the third and fourth sidewalls are attached via hinges to opposite marginal edges of the bottom wall. The top edges of the third and fourth walls are attached to the underside of the rigid housing by two hinges. The fold mirror is mounted via a hinge to the inner surface of the bottom wall. The projection head assembly which includes a projecting lens and a projection mirror is attached to the rigid housing by a post, a rack and pinion gear mechanism and a mounting arm.

Abstract: The overhead projector dry-erase accessory of this invention comprises a transparent, rigid, multi-layered body (12) into which overhead transparencies can be placed and utilized. The multiple layers of the device are created by either folding a single piece of transparent substrate in half, or by attaching two separate transparent plates at a single peripheral seam, with an adhesive strip 22. A transparent, dry-erase overlay (16) covers the top surface of the device, with the overlay being attached to the device at two opposing edges. A plurality of overlay spacer and attaching strips (18) both join the overlay (16) to the top plate of the device (14) and raise the overlay off of the top plate so as to create an air pocket for placement of tabbed or untabbed inserts therebetween. The attached edges of the overlay and the top plate of the device are protected, and the peripheral seams are further reinforced by a protective cap (20) placed over and further reinforcing them.

Abstract: A liquid crystal display (LCD) panel employs a cholesteric polarizer which passes light of a first circular polarization, but reflects light of a second circular polarization. The LCD panel may be monochrome or color; in the color embodiments, several different color filters are used, each having one or more cholesteric polarizers tuned to a specific bandwidth in the visible spectrum. These polarizers replace dyed (neutral or dichroic) polarizers of prior art LCD panels, and provide improved color purity. The invention may be enhanced by providing a light recycling scheme whereby the handedness of the circularly polarized light reflected by the polarizers is changed and redirected back to the polarizers. This recycling scheme may also be adapted to provide an overhead projector having a high output polarized light source, particularly useful in conjunction with an LCD panel.

Abstract: An overhead projector for irradiating a spatial light modulator with reading light to read out a subject image written in the spatial light modulator with writing light and projecting the subject image read out with the reading light, wherein the spatial light modulator consists of photoconductive layer for receiving the writing light coming from a subject to reproduce the subject image, light modulating layer formed by a liquid crystal of which molecules are arranged in a homeotropic orientation for modulating the reading light of which a waveband is limited to a prescribed range according to the subject image reproduced in the photoconductive layer, and a dielectric mirror having wavelength selectivity for reflecting the reading light with the waveband modulated by the light modulating layer.

Abstract: A sheet of imageable film for use in an overhead projector is provided with at least one, and preferably two, opaque flaps attached in a foldable manner to the film so that the flaps may be unfolded to prevent unwanted light from shining past the edges of the transparency.

Abstract: A low-profile, transmissive overhead projector (OHP) employs a novel condensing lens system having a catadioptric Fresnel lens and a dioptric Fresnel lens. Each of the lenses exhibits chromatic aberration, but the dispersion of one lens is selected to cancel out the dispersion of the other, e.g., if the catadioptric lens has negative dispersion then the dioptric lens is selected to have positive dispersion. The mutual cancellation of the dispersion of each lens practically eliminates longitudinal chromatic aberration through the lens system. The lens system provides a fast condensing system which allows collimation, dispersion or concentration of light striking the lens at a high angle of incidence. This characteristic is particularly suited for a low-profile OHP as it allows the light source to be placed directly under, but very close to, the stage area.

Abstract: A projection inspector which projects the image of an object being measured onto a screen for a visual inspection. It may be used with a microscope for observation in detail. Unlike the conventional projection inspector, the inspector fully exhibits high degree of measuring function even at the time of inspecting an object having a surface color and shape that can be difficultly imaged, and projects the object's image onto the screen to inspect it, and further enables the object's image to be more correctly observed or inspected using a microscope.

Abstract: An overhead projector (OHP) presentation system uses a liquid crystal display (LCD) panel to project electronically stored graphic images. The OHP preferably includes an integrated computer having a plurality of output ports for connection to various peripheral devices. A novel interface card is also used to provide electrical connections between the computer and the LCD panel, providing the further benefit of aligning the transmissive portion of the panel with the stage of the OHP. The LCD panel may be designed to swing horizontally into the optical path. This may be accomplished by providing a sliding drawer which inserts the panel within the body of the OHP, or by pivotally attaching the panel to the stage of the OHP.

Abstract: A low-profile transmissive overhead projector employs a folded optical path and an off-axis Fresnel lens condensing system which includes a catadioptric lens element. This lens provides a fast condensing system which allows collimation, dispersion, or concentration of light striking the lens at a high angle of incidence, with efficient transmission to the far edge of the lens. This also enables additional reduction in the OHP base height by allowing the single mirror to be mounted at a flatter angle, with the light source still maintained at a position below (and adjacent) the stage. A novel catadioptric lens design further imparts achromaticity to the element, so that it may be constructed of any material, regardless of its index of refraction. The condensing system may have a single or doublet catadioptric lens.

Abstract: An automatic latching mechanism for the post of an overhead projector includes a spring-biased collar slidably disposed on the post and a cam which lifts the collar as the post is raised and releases the collar to engage a retaining tang when the post reaches a position necessary for projection.

Abstract: A relatively small liquid-crystal display (LCD) device located well above the fresnel stage of an overhead projector produces large, sharp images with full color and motion. A focus-correcting lens moves with the overhead projector's optical head to maintain proper projection-focus and magnification. Spectrally-selective filters are interposed between the LCD device and fresnel stage to avoid LCD deterioration. A fan-actuated shutter or electrically-actuated shutter optionally provide still further protection. Optical collimation methods are employed to attain a large depth-of-field and image brightness.

Abstract: An adjustment mechanism for use with an overhead projector having a post extending upwardly to support a projection head attached to the attachment mechanism incudes a wear pad partially surrounding the post, a friction pad disposed opposite the wear pad with respect to the post and a spring for urging the friction pad into the post.

Abstract: An arm carrying the projection head of an overhead projector is swingable mounted on a pivot body received in a guide at one side of the housing of an overhead projector so that the entire pivot can drop into this guide in the operative upright position of the arm. In that position, the segment of the arm adjacent the pivot is locked by the guide in its upright position.

Abstract: An overhead projector (OHP) presentation system uses a liquid crystal display (LCD) panel to project electronically stored graphic images. The OHP preferably includes an integrated computer having a plurality of output ports for connection to various peripheral devices. A novel interface card is also used to provide electrical connections between the computer and the LCD panel, providing the further benefit of aligning the transmissive portion of the panel with the stage of the overhead projector.

Abstract: The overhead projector include a lower plate disposed on a housing of a main body of the overhead projector. The lower plate can rotate about a light axis of a condenser lens and has a transparent portion facing at least the condenser lens. A projection lens is supported above the condenser lens and an upper plate is disposed under the projection lens. The upper plate is supported vertically resiliently with respect to the projection lens and has a transparent portion at least facing the condenser lens. The upper plate is able to rotate about a light axis of the condenser lens. When images projected on a screen lie sideways or upside down, the upper and lower plates which are interposing a film therebetween are rotated. Thus, the directions of the projected images are correctly adjusted.

Abstract: The objective of the invention is an overhead projector (1) supplied with acetate film rolls (4), to which projector belongs a body (2) onto which is fixed a projection arm (16) equipped with a lens/lenses (21) and a flat mirror (20). The body (2) is supplied with an openable top part (3) into which roll spaces are arranged for the acetate film rolls (4). The acetate film rolls (4) are installed on axle rods (26) which are supplied with rotating cylinders (5) and mounted in the top part (3) at opposite ends in the shaped spaces with the aid of a bent spring and fixing hole. In the inner side of the body (2) is also arranged at least one shutter screen element (10-13) that stays inside the body (2) in all cases of use, and which is installed to cover the projected part of the acetate film (6) fully or partially. The screen elements are moved in a flat level on guiding rods (15 ) inside the body (2) in the directions of the length and/or width of the body (2) with the help of levers (14).

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: The invention relates to an overhead projector for projecting images, said projector including a liquid crystal display panel arranged in the imaging plane, an optical imaging unit and a lamp and reflector arrangement accommodated in a housing as well as a scanning means for stored data. Adjacent to the platen (18) covering the liquid crystal display panel (17), a data strip scanning means (20) is provided which is accessible from outside. A transparency (23) which shows pictures, diagrams or the like and can be placed on platen (18) comprises a data strip (25) for selective and/or joint projection with the liquid crystal images, said data strip extending into the area of the scanning means (20) when the transparency (23) is placed on platen (18).

Abstract: A masking device is provided for use with projectors, such as an overhead projector, to selectively block the projection beam that carries an image disposed on a substrate, such as a transparency, for projection onto a viewing screen. The masking device has a framework having preferably guide rails that form slideways receiving a shutter panel. A transparency is aligned by the guide rails and the shutter panel has a leading edge that extends transversely across the aligned transparency so that only the image portion forward of the leading edge is projected. The shutter panel is constructed of a material that inhibits the projectiton beam, but allows the projection to read or view the image portion that is blocked. A base plate of transparent material supports the guide rails and provides a stage on which the transparency may be positioned for projection of the image disposed thereon.

Abstract: This invention is for an overhead projector to be used with at least one large stage aperture and a small stage aperture above a Fresnel lens, comprising a light source mounted below the plane of the stage, characterized by a single or multi-element condenser which can be positioned between the lamp housing and Fresnel lens. In the case of a small stage aperture, the condenser focuses the light flux designed for the large stage aperture onto the small stage aperture.

Abstract: A transparent viewing sheet has a plurality of facial features outlined thereon and is used for form am image by viewing the facial features thereon. Rotatably concentric transparent facial feature rings are disposed in overlaid relation with each other and have different facial features outlined thereon but in different shapes and sizes. The facial feature rings are rotatably movable relative to each other and are arranged to align a plurality of facial features at a common point in their overlaid position to form an image as is it appeared in the viewing sheet. The facial feature rings are mounted on a base sheet having a viewing window therein whereby to view the formed image. The transparent viewing sheet may be used in combination with a mirror to form an image to be used to form the completed image.

Abstract: An electronic transparency device is provided with a memory in which a plurality of frames of video data ("slides") can be stored. The apparatus includes a control microprocessor which can cause predefined sequences of slides to be presented on the LCD panel automatically. These slide "shows" are defined by the user using a hand held remote control unit in conjuntion with menus displayed on the LCD panel in window fashion by the microprocessor. The user can specify the duration that each slide in a sequence is to be shown, the video transition by which it is to be introduced, the degree of "windowshading" with which it is to be displayed, etc. Once a show is defined, it can be instituted and controlled from the remote control unit. Among other numerous features, the transparency also includes a pointer that can be superimposed on the display and controlled by the remote control unit. This pointer can be used to define certain portions of the screen that are to be displayed in highlighted fashion.

Abstract: This invention consists of a wide-angle, multi-element condenser system for an overhead projector that provides uniform illumination at the plane of the projection transparency, and a well-formed lamp image at the entrance pupil of the projection lens. This is accomplished by using a combination of a glass spherical meniscus lens, a glass plano-convex spherical lens and a plastic aspheric Fresnel lens system.

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.