Abstract: A projector of a reflection type has a transparent stage plate on which a transparent original sheet is set. A lamp illuminates the original sheet through the stage plate. A Fresnel mirror is laid on an upside of the original sheet, and reflects light from the original sheet in a convergent manner. The light from the Fresnel mirror is reflected away from the stage plate. The light is again reflected, and incident upon a projecting lens, which projects an image of the original sheet to a screen. A housing contains the Fresnel mirror in movable fashion. An inserting slot is formed in the housing, into which the original sheet is inserted during supply of the original sheet. Photo sensors operate to detect a front edge of the original sheet inserted through the inserting slot. It is also detected that the original sheet is set on the stage plate. An ejector switch is operated for ejection of the original sheet.

Abstract: A real image direct front projector includes a housing with a plane transparent object support for placing objects thereunder and for permitting light emitted from at least one light source to pass therethrough. A projection lens is mounted concentrically above the object support for producing an object image on an image wall outside of the projector. The projection lens is located above and vertically within the circumference of the object support. The object support has in at least a predetermined area thereof a plurality of microprisms on a side of the object support facing away from the object.

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 overhead projector that irradiates light onto an object or a sheet of paper, focuses the light reflected therefrom with a focusing lens, isolates ultraviolet or infrared rays having a specific wavelength among the focused light via a filter, forms an image by irradiating the isolated light onto an image former, and projects the image onto a projection screen by irradiating visible light onto the image former whereby the image is enlarged and projected via a projection lens to thereby obtain a more clear image.

Abstract: An overhead projector a base table, which has a stage on which an original is placed. A projecting head includes projecting mirror and lens, and forms an image of the original. A stand has bottom and top ends. The bottom end is mounted on the base table. The stand swings between an erected position and a folded position where the stand is superposed on the stage. The projecting head is mounted on the top end in swingable fashion. An extension coil spring is disposed between the stand and the base table, biases the stand from the folded position to the erected position, and has biasing force decreasing according as the stand comes nearer to the erected position. A gas spring is disposed between the stand and the base table, biases the stand from the folded position to the erected position, and has biasing force increasing according as the stand comes nearer to the erected position.

Abstract: An overhead projector has a flat stage, for placing a sheet material thereon, which is inclined such that a normal line of the flat stage, which is in alignment with the optical axis of the projection lens, inclines an angle relative to a vertical line so that a reflection mirror disposed above the projection lens at an angle of 45 degrees directs an image projected by the projection lens toward a remote screen at a desired angle of elevation.

Abstract: An overhead projector has a stage on which original material is placed. The stage has a Fresnel mirror. An electrostatic attracting structure is integral with the Fresnel mirror. The attracting structure includes a conductive membrane of ceramic and a resinous dielectric/protective layer. The conductive membrane consists of a pair of comb-shaped electrodes, which interfinger in coplanar fashion, and are covered by the dielectric/protective layer for insulation and protection. A power supply device applies a high voltage of direct current to the electrodes. The original material is attracted electrostatically by the electrodes, and can be kept flat on the stage. In a preferred embodiment, the power supply device incorporates a self-starting blocking oscillator, which is adapted to boost the voltage sufficiently for electrostatic attraction.

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: A reflecting illumination type projecting device includes a projecting lens having an optical axis intersecting an object to be tested, a light source portion for illuminating the object through the projecting lens, a screen onto which an image of the object is projected by light reflected on the object through the projecting lens, and an optical path separating element disposed in the vicinity of an exit pupil, the element being formed with a total reflecting mirror portion for reflecting either the illuminating light or the reflected light and with a transmitting portion for transmitting the remaining light, thereby to make the illuminating light incident to the projecting lens and to guide the reflected light toward the screen.

Abstract: A reflecting illumination projecting device includes a light source which emits illuminating light and a mirror which reflects the illuminating light emitted from the light source. A transmission type image forming portion is provided between the light source and the mirror to form a pattern to be projected, and a projecting lens is provided between the light source and the image forming portion. An optical path separating element is disposed in the vicinity of an exit pupil of the projecting lens. The optical path separating element includes a first portion for introducing substantially all of the illuminating light to the projecting lens and a second portion for introducing light reflected by the mirror onto the image projection plane.

Abstract: In order to provide a display apparatus which can express projected images of small characters, illustrations or the like in not only the daytime or an illuminated bright place, but also the nighttime in the case where brightness is deficient, besides which can be used in not only the outdoors, but also the inside of a dark room, the present display apparatus comprises a mirror Fresnel lens, an original picture for projection positioned over the surface of the mirror Fresnel lens, and a projection mechanism positioned on the surface side of the mirror Fresnel lens and at the same time, disposed so as to emit light on the surface of the mirror Fresnel lens, further the light emitted from the projection mechanism being reflected by the mirror Fresnel lens to project an image of the original picture for projection on a prescribed plane of projection.

Abstract: A reflecting illumination type projecting device includes a projecting lens having an optical axis intersecting an object to be tested, a light source portion for illuminating the object through the projecting lens, a screen onto which an image of the object is projected by light reflected on the object through the projecting lens, and an optical path separating element disposed in the vicinity of an exit pupil, the element being formed with a total reflecting mirror portion for reflecting either the illuminating light or the reflected light and with a transmitting portion for transmitting the remaining light, thereby to make the illuminating light incident to the projecting lens and to guide the reflected light toward the screen.

Abstract: A reflective overhead projector is provided with two lamps for the purpose of allowing change from one to the other of the lamps in the event of expiration of the lamp in use. The lamps are arranged to face the center of a circle at which is positioned a rotatable planar mirror which may be turned to direct light from a desired one of the two lamps. An electrical switch senses the position of the mirror and directs electrical power to the appropriate lamp.

Abstract: An apparatus and method for projecting optical images from opaque or transparent objects onto a remote viewing screen includes a plane mirror combination and a reflective projection means. The plane mirror combination comprises an image inverting plane mirror and an image reversing plane mirror. The image inverting plane mirror is positioned angularly over the illuminated object and converts the upright and nonreversed object image into an inverted and reversed image. Disposed close by the image inverting plane mirror is the reflective projection means which comprises a parabolic concave mirror the parabolic concave mirror captures the inverted and reversed image and projects it onto the image reversing plane mirror near by as an enlarged, upright and reversed image. In return, the image reversing plane mirror reflects the enlarged, upright and reversed image onto the remote viewing screen as an enlarged, upright and nonreversed real image.

Abstract: An overhead projector comprises a hollow base comprising a writing plate and a reflective Fresnel lens below the writing plate and an air space below the Fresnel lens. A hollow support arm projecting up from one side of the base carries a projection head having an objective lens and deflection mirror. A lamp mounted in the transition between the support arm and the projection head directs light on the writing plate. The hollow support arm is in communication with the interior of the base to provide a cooling air flow path between openings in the base at the side opposite the support arm and openings in the support arm adjacent the projection head, behind which latter openings a blower is mounted. Ribs in the hollow base define air flow distributors for effectively cooling the Fresnel lens and electronic circuit components mounted in the hollow base.

Abstract: A reflective stage overhead projector has a light source, a projection lens and mirror assembly for focusing and reflecting an illuminated image onto a screen, and a stage area for supporting an image to be illuminated and projected. One reflective surface of the stage area is defined by a noncentral portion of a Fresnel lens.

Abstract: An opaque projector includes a light source, a stage through which the light radiating from the light source passes and on which an object is placed, a projection mirror for reflecting light reflected by the object, and a projector lens for gathering the light reflected by the projection mirror to form an image of the object on an image projecting surface located outside of the projector. A reflection mirror for reflecting the light from the light source to illuminate the object is provided on each of the two sides of the projection mirror. The light source is disposed in front of the projeciton mirror and on the inner sides of the reflection mirrors.

Abstract: A portable overhead projector having a folding arm. The arm and a torque member are pivotally attached to the projector head, forming a four bar linkage. When the arm is moved from an upright, operative position to a storage position, the projector head rotates so as to be flush with the base of the projector, making the projector more compact for storage. An adjustment mechanism is also provided to automatically open and close a mirror which is attached to the projector head, simplifying the set up procedure of the overhead projector.

Abstract: Educational apparatus for use with an overhead projector has a transparent grid with horizontal and vertical indices for projecting a grid onto a wall screen. A plurality of removable cover pieces, keyed to the grid, cover up grid segments whereby when the transparent grid has pictorial material a student, or player, may project a particular grid segment by picking up the cover piece on that segment.

Abstract: A liquid crystal display assembly for use with a reflective type overhead projector includes a liquid crystal display and an attached Fresnel reflector portion which is off-axis in that the center of the reflector is not included in the Fresnel reflector portion so that a spurious bright spot coinciding in the projected image with the center of the Fresnel reflector is eliminated.

Abstract: An optical apparatus having a base table on which an original is placed and an image forming unit with an optical system which projects an image of the original onto a remote screen for showing the same to a number of viewers. A foldable structure is provided, having a support structure mounted on a base table for movement between a lowered position covering the base table and a raised position wherein the image forming unit is located above the base table so as to form and project the image of the original onto the remote screen. A linkage interconnects the image forming unit and the support structure for causing a movement of the image forming unit relative to the support structure upon movement of the support structure between the folded and unfolded positions, thereby placing the image forming unit above the base table when the supporting means is in the raised position and flush with the support means so as to cover the base table when the support means is in the lowered position.

Abstract: An opaque adapter for an overhead projector uses a hood with clamshell doors to provide generous access to the projector stage during transparency projection and efficient light shielding during opaque projection. The clamshell doors are oriented upon hinges slanted to the vertical so as to rise away from the stage when opened. Spring devices offset the gravitational forces on the doors, allowing rapid motor actuation with very little power. Dual dichroic optics maintain a cool stage despite high light intensity, and internal baffles further increase brightness.

Abstract: An overhead projector comprises a housing having an upwardly facing writing plate and a Fresnel lens below the writing plate. A hollow support arm extending up from one side of the housing supports a projection head comprising a lamp directing light down onto the writing plate, a variable objective lens receiving an image from the writing plate and a deflection mirror for directing the image onto a projection screen. A power supply in the support arm supplies power for the projector including the lamp and a blower in the support arm for cooling the power supply and lamp. A microprocessor in the support arm has inputs receiving signals from sensors for sensing the distance from the projector to the screen, ambient brightness, brightness contrast in the projected image on the screen and the temperature of the power supply and the microprocessor. The microprocessor has outputs for regulating the focus of the objective lens, the speed of the blower, the brightness of the lamp and the voltage of the power supply.

Abstract: An overhead projector comprises a flat base accommodating a reflective Fresnel lens below a writing surface. A hollow arm projecting up from one side of the base supports a projection head comprising a light source, an objective lens assembly spaced horizontally from the light source, a first deflection mirror for directing rays from the light source down onto the writing surface and reflective Fresnel lens and a second deflective lens for directing rays from the writing surface and reflective Fresnel lens out through the objective lens assembly. The objective lens assembly is tiltable to direct light rays on an upwardly inclined path and the second deflection mirror is also tiltable and is coupled with the objective lens assembly so as to be tilted half as much as the objective lens assembly.

Abstract: A Fresnel lens is mounted on a base in the form of a thin rectangular plate to be placed on a flat table. A document to be projected is put on the Fresnel lens. A main projector body housing a power supply is pivotally mounted on one end of the base. A head having a light source and a mirror is angularly movably coupled to a post arm which is angularly movably or telescopically coupled to the main projector body. When not in use, the base, the main projector body, the head, and the post arm are collapsed and combined into a single block body for easy transportation and storage.

Abstract: In an overhead projector comprising a writing plate, and under this arranged Fresnel lens, a light source and an objective carried by a carrying arm, the problem to be solved is to overcome the disadvantages of the state of the art and to provide a possibility for a lecturer to make information retrieved from an electronic information source, for example, a computer or an electronic game, accessible to a large viewer and listener circle. The invention solves this problem thereby, that between the Fresnel lens and the writing plate there are arranged a layer of liquid crystals which are aligned in an electric field and transparent electrodes on both sides thereof, whereby two of the plates or films traversed by the light beam have light polarizing properties.

Abstract: An overhead projector comprises a base, a hollow post extending up from the base and a projection head on an upper portion of the post. The projection head comprises a light source, an objective lens and a deflection mirror. A power supply unit housed in the post supplies power to the light source and to a ventilating fan inside the post between the power supply unit and the projection head. Openings in the post provide for circulation of cooling air by the fan over both the light source and the power supply unit. The power supply unit includes interchangeable input stages which can be plugged into a socket in the post to adapt the power supply unit to different voltages and currents. A slide or microfilm projector mounted adjacent the projection head projects on the base an image which is then re-projected onto a wall or screen by the projection head. For use at conferences, a conference table top is provided with a plurality of sockets into which the posts of overhead projectors can be plugged.

Abstract: In a reflecting type overhead projector having a light source lamp and a projection lens above a reflecting table formed of a Fresnel lens and a mirror upon which an original to be projected is laid, there is provided a control circuit which switches over supply of electric power to the light source lamp between full and part power supply according to whether the intensity of the light beams from the light source lamp received by a photosensitive element provided in the vicinity of the reflecting table is higher or lower than a predetermined value.

Abstract: A projector comprises a substantially horizontal table, a substantially centrally above the table arranged projection optics (2), a light source (3) which is located above the table and arranged to illuminate the table, a deflexion mirror (4) for substantially horizontal deflexion of a light radiating vertically upwardly from the table, and a light shaft (5) which at least partially screens off the area between the optics (2) and the table (1) from the surroundings and is characterized in that a covering (6a) is arranged to be laid out over the table surface in that the upwardly facing surface of the laid out covering is light-reflecting, while the table surface is light-absorbing preferably black and mat, alternatively that the upwardly facing surface of the laid out covering is light-absorbing while the table surface is arranged to emit light vertically upwardly.

Abstract: A first lens system projects an image onto an optical director which converges the light from the image into a second lens system which reprojects the image onto a screen to be viewed by an audience.