Abstract: In an image projecting apparatus such as a microfilm reader and a microfilm reader printer, the inclination angle of a screen surface can be changed without causing distortion and blur in a projected image on the screen surface. The inclination angle of the screen can be changed for the user to see the screen surface with ease such that the screen surface becomes perpendicular to the user's line of sight and the external light reflected by the screen surface is prevented from entering the user's eyes.

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 VTR equipped with an LCD projector integral therewith, capable of eliminating the complexity of wirings and preventing degradation of video signals. The VTR includes a front screen, a rear screen disposed on a front panel of a VCR body and constructed to be openable and closable for the LCD projector projecting the image, a closing detecting unit for detecting an openable or closable state of the rear screen, an image inverting unit for laterally inverting a direction of the image to be projected onto the rear screen, the rear screen being opened when a viewer observes the image projected on the front screen, while being closed when the viewer observes the image projected on the rear screen, the detecting unit informing the image inverting means of the closed state of the rear screen, and the image inverting unit laterally inverting the image to be projected onto the rear screen upon receiving the information.

Abstract: To provide an oblique projection type displaying apparatus for radiating rays of light which are nearly parallel with a light bulb, thereby preventing the brightness of a resultant image from becoming uneven, the apparatus comprises a light source, optical modulating means, projecting means for projecting an image generated by the optical modulating means on a screen, and the screen, wherein a center optical axis of rays of light projected by the projecting means are obliquely entered into the screen, wherein the projecting means comprises first projecting optical means for converting an image generated by the optical modulating means into an intermediate image with trapezoidal distortion, and second projecting optical means for converting the intermediate image with trapezoidal distortion into an image without trapezoidal distortion on the screen, and wherein the first projecting optical means comprises two lenses which are not parallel each other.

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: A projection-type television having a movable reflective mirror provides a simple structure having a pleasing external appearance. A reflective mirror for reflecting images is movably installed on a guider so as to be moved back and forth by the guider in a perpendicular direction with respect to a screen on which the images are displayed.

Abstract: Back-projection display system including a screen which can be moved away from or, conversely, placed up against a support such as a wall, for example. A projector located at some distance away, on the ceiling for example, illuminates a back-projection mirror located at 45.degree. in relation to the illumination beam and in relation to the screen. The back-projection mirror itself is also articulated. In addition, the mirror may be made in the form of a holographic mirror.

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 portable liquid crystal display (LCD) projector with a bag type housing containing therein an optical part and a mechanical part which is capable of being used in both front projection type and rear projection type and enhancing the carrying performance while having a proper screen size. The projector includes a fixed mirror and a movable mirror disposed between a projection screen and a screen, and a fixed LCD mirror disposed between the LCD and the projection lens. The screen is detachably mounted to a screen holder which is movably mounted to a housing and provided with a rectangular transmitting hole and mounted to the screen holder is a mirror holder attached with the movable mirror.

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: 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 rear projection television set in which a lenticular sheet is superposed to a Fresnel lens to form a light transmissive screen, at least one projection cathode ray tube projects an image onto the Fresnel lens so that the image through the lenticular is viewed by a viewer. A projector lens is mounted to the projection cathode ray tube and has an exit pupil so as to project the image from the projection tube onto the Fresnel lens. The image through the lenticular sheet is viewed at a distance from the lenticular lens, wherein there is a relation a.times.b<5.5 where a is distance between the exit pupil of the projector lens 2 and the Fresnel lens 1, and b is a condensing distance for a maximum radius equal to the vertical dimension of the screen.

Abstract: A rear screen projection system integrated into the passenger cabin of an airplane. The system has a projector that directs a picture into the inner cavity of a housing. Also attached to the housing is a screen that has a first surface that faces the audience and a second opposite surface exposed to the inner cavity of the housing. Located between the projector and the housing is a mirror that reflects the picture from the projector onto the second surface of the screen. The screen is transparent to light so that the audience can view the picture on the first surface of the screen. The mirror is positioned such that the distance between the projector and the top and bottom edges of the screen are essentially equal. The mirror is also positioned such that even with an overhead projector, the incidence of light is normal to the screen and the picture is directed down toward the audience.

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 liquid crystal projector includes a liquid crystal panel, a light source for illuminating the liquid crystal panel, a back-projection type screen having on its surface a lenticular lens in which many vertical or horizontal stripe lenses are arranged in parallel, a projection lens for enlargedly projecting light transmitted through the liquid crystal panel onto the back-projection type screen, a light-falling polarized plate arranged between the light-falling plane of the liquid crystal panel and the light source, for transmitting the light from the light source, and oscillating in a predetermined direction, to fall on the liquid crystal panel, and an image-forming polarizing plate arranged between the light-outgoing plane of the liquid crystal panel and the projection lens or in a projection path from the projection lens to the screen, to allow the liquid transmitted through the liquid crystal panel, and oscillating in a predetermined direction, to pass through, thereby forming a light image.

Abstract: A rear projection screen assembly comprising a transparent screen suitable for passage therethrough of a light beam emanating from a rear projector apparatus, means for supporting the screen such that it is positionable to intercept the light beam, means in operative association with the screen, for supporting at least one sheet of translucent material, such that the transluscent material can be releasably fixed to the screen adjacent a screen surface opposite the screen surface first encountered by the light beam; and a kit suitable for construction of a rear projection screen assembly; and further includes a method of graphically modifying an image projected by a rear projection apparatus.

Abstract: A transmissive original projecting apparatus has an illuminator for illuminating a transmissive original, a projector for directing light transmitted through the transmissive original to the original supportion portion of an original reading apparatus, and a connecting device for connecting the illuminating illuminator and the projector together.

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 display device includes equipment for projecting light onto a surface. The equipment includes a beam-splitter for effecting partial reflection and partial transmittance of an incident beam. On one side of the beam-splitter are a light source for directing light onto the beam-splitter and a mirror for directing back towards the beam-splitter light reflected therefrom. On the other side of the beam-splitter is a louvre for permitting passage therethrough of light of incident angle relative to a normal to the beam-splitter with in a predetermined restricted range.

Abstract: A clothing image mirror projection system for producing a composite image of an article of clothing superimposed upon the reflected image of a viewer's face includes a two-way mirror, a rear projection screen, and apparatus for projecting an image of an article of clothing onto said rear projection screen. The present system includes an anamorphic lens assembly to adjust the dimensions of the clothing image along a horizontal axis. Further, the present system includes means by which the height and weight of the subject are measured by sensors, and used to automatically adjust the height and width of the clothing image so as to fit the height and general size of the subject viewer.

Abstract: Projector apparatus including a light source, a projection head and a projection stage aperture for an object, the image of which is to be produced. The aperture is situated in the ray path between the light source and the projection head. An ellipsoidal mirror is situated in the light path between the light source and the aperture. One focal point of the ellipsoidal mirror substantially coincides with the light source and the other focal point of the mirror substantially coincides with the projection head. The projection head includes a deflection means. The projection head is situated substantially in a plane constituting a normal plane to the aperture plane and containing the front edge line of the aperture, as observed in the generally horizontal projection direction.

Abstract: A projection system comprising from the image end a screen, a lens in which a core portion including the lens axis accomplishes a convergence function and in which a peripheral portion including a lens edge thereof accomplishes the divergence function, a convex lens element, a concave lens element and a CRT having a face glass whose inner surface is coated with a phosphor and is so curved to form a fourth lens element with a curvature center within a core portion including the lens axis is disposed on the screen side of the projection system, the curvature radius of each part of the core portion of the fourth lens increasing thereof in accordance with increments of the semi-aperture distance of each part from the lens axis.

Abstract: A microfilm reader which has an optical system for magnifying and projecting an image recorded on a film contained a cassette onto a viewing screen mounted on a pivot shaft of a casing having a generally rectangular flattened box-like configuration of the microfilm reader for folding and unfolding movement comprises a cassette holder, a microfilm driving device for transporting the microfilm so as to place a frame of the microfilm of which an image is to be projected, a reflection mirror supported by the casing for sliding movement so as to be foldable in order to turn the projected image toward the viewing screen, a top cover mounted on and supported by the casing for folding and unfolding movement which is slidably engaged with a top end of the viewing screen so as to define a dark space behind the viewing screen in cooperation therewith when the viewing screen is unfolded and to cover and protect the viewing screen when the viewing screen is folded, and linking device interconnecting the viewing screen and

Abstract: A rear projection screen is provided for observing an image by introducing light from the rear side of the screen at a sharp angle. The screen has a plane of incidence which comprises a plurality of prisms extending in lines or arcs. Each prism has a total reflection surface which totally reflects incident light so that the light emerges toward an observer and a surface opposite to the total reflection surface, and toward the total reflection surface and/or the opposite surface having a curved surface so that the luminous flux of the totally reflected light is once converged and is then diffused.

Abstract: The installation permits the adjustment in succession on a screen E of the size of a series of typical images which are to be made to merge with the image of a person P so as to enable this person to view through a mirror M composite images thus obtained. The projector and its mirror M 2 are slidably mounted on a funicular railway whose rails 16 and 17 have a slope equal to the slope of the lowest ray of the projected beam.

Abstract: A projection television receiver having a more compact cabinet size due to an improved projection lens system. The projection lens system includes a plano-concave lens and a plano-convex lens having optical axes forming an angle in a range of 170.degree. to 190.degree.. First and second mirrors are positioned rearwardly of the plano-concave mirror and the plano-convex mirror to reflect light rays from the plano-concave mirror parallel to the optical axis of the plano-convex mirror. A convex lens is positioned between the two mirrors and the optical path between the plano-concave mirror and the plano-convex mirror.

Abstract: An apparatus for sensing microfilms is provided in addition to visible light with a projection lamp for radiating infrared rays which pass through a cold-light mirror to a platform on which a microfilm is disposed. The apparatus is further provided with a projection lens positioned above the microfilm platform. The path of rays is directed from the microfilm platform through the projection lens and then is projected onto an image screen or other sensing surface, for example CCD-device. For adjusting the apparatus for various light spectrum combinations the apparatus is provided with at least one infrared component-reflecting mirror which is displaceable or pivotable to and from the path of illumination rays radiated from the projection lamp.

Abstract: A rear projection apparatus has a cabinet provided with a screen attaching portion, a rear projection screen attached to the screen attaching portion, an image projector for projecting an image onto the rear projecting screen from its back side, and a convex lens disposed at the back side of the rear projection screen, wherein the optical axis of the convex lens is shifted from its mechanical or dimensional center, and the convex lens is removably mounted to the rear projection screen so that the orientation of the lens relative to the screen can be altered whereby the light axis of the image from the rear projection screen is deflected to a predetermined direction by altering the orientation of the convex lens having the shifted optical axis in relation to the screen. The screen attaching portion of the cabinet permits altering the orientation of the lens and, thus, the direction in which the projected image is deflected, without increasing the size of the cabinet.

Abstract: A portable display device for projecting on a built-in rear projection screen a road map, navigation chart and the like. The road map or navigation chart is in the form of one of a plurality of microfilm frames removably installed in a cut-out portion of a hollow drum in which is disposed a projection lamp. The drum is indexable in angular position and in longitudinal position such as to display an appropriate portion or frame of the microfilm.

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 microfiche reader assembly especially suitable for use in a desk drawer of typical size is disclosed herein. This assembly includes a housing, a projection screen, a microfiche support arrangement for supporting a microfiche for movement within a given rectangular operating area and an optical arrangement cooperating with the supported microfiche for projecting an enlarged image of a section of the microfiche on to the screen when the microfiche is in its operating area. While this assembly requires more room than the standard desk drawer allots during use, it is made sufficiently collapsible to fit entirely within the confines of the drawer when not in use so as to allow the drawer to be closed. However, at the same time, the assembly is expandable for use within the drawer when the latter is opened, whereby the assembly does not have to be removed.

Abstract: The microfiche projector enlarges the image onto the flat white undersurface of the top panel of the enclosure which has a flat black interior. The viewer sees the image reflected in the adjustable 45.degree. mirror. The apparent image is about 50" in front of the user to reduce eye fatigue. The image is non-directional which allows considerable movement of the user.

Abstract: A method is disclosed of projecting images on a screen which are so bright as to be easily visible in a lighted room, including projecting a pair of stereoscope pictures which can be seen in three dimensions without the observer wearing special spectacles or using other personal optical aids. The combination includes a large projection optic combined with a special screen which acts as a screen but which also has focus power and casts an image of the projection optic out in space in a limited viewing area for the observer's use in viewing a single two dimensional picture. In a modified form of the invention the large projection optic is divided into an array of segments where adjacent pairs of segments separately project each of a pair of stereoscopic pictures onto the screen.

Abstract: An X-ray microfilm reader comprises a microfilm medium holder for holding same in a working position and a light source disposed below the working position which reflects light from a dichroic mirror towards the microfilm medium through a condenser. The image from the microfilm medium passes through any one of a plurality of projecting lenses and through a coner and is thereafter reflected by an image mirror onto a screen for viewing by the user.

Abstract: A pocket-sized microform reader is realized by employing a unique lenticular (screen) assembly and a projection lens assembly, the latter permitting a fold in the middle of an optical path allowing the size requirements of such a reader to be met. The cooperation between the lenticular screen and the projection lens assemblies permits sufficient brightness to be obtained and the lenticular screen assembly defines a non wasteful exit pupil of limited dimensions consistent with a pocket-sized reader.

Abstract: This invention presents a film reader equipped with a reflecting type screen, which is arranged in a housing of the reader and has a number of ring strip surfaces having different inclination angles and arranged concentrically. The common center of the ring strip surfaces is deviated from the center of the screen and located outside of the screen, and the end of the screen nearest to the common center is placed near an observing aperture in the housing. A light source for illuminating a microfilm having recorded images and an optical system for projecting the image of the illuminated film to the screen are provided. Further, the screen is formed by one synthetic resin or preferably at least two kinds of synthetic resins having different refractive indices and mutually nonsoluble property. A reflecting substance may be mixed with said resins.

Abstract: A microfiche viewer with a light projection path whereby different images on an individual piece of microfilm can be placed in the light projection path for viewing. The fiche is rectangular in configuration and is inserted into the viewer with the shorter side parallel to the front of the viewer. A rotatable base is attached to the bottom of the viewer which is designed to limit the angular rotation of the microfiche viewer.

Abstract: A motion picture projector in which projector mechanisms are incorporated in the body of a carrying case, the opening of which is covered by a panel structure on which a reel setting portion and an operation board are disposed. The panel structure is provided with a projection window through which a light beam from the projector mechanisms is projected. A cover attached to the case body by hinge means is provided in the inside thereof with a rear-projection screen assembly, which is adapted to engage the case body and to be supported in a predetermined angle together with the case cover when unfolded. A light beam from the projection window is reflected by a mirror disposed in the inside of the case cover so as to be projected on the screen assembly. A projector in accordance with the present invention is formed in a readily portable shape and has high versatility because films wound upon usual open-type reels are available. In addition, the projected image is easy to see because of the large screen size.

Abstract: A projector for projecting a successive series of pictures and, in particular, an audiovisual information device, includes a housing, a projector disposed within the housing and a projection face which is provided in close proximity to the rear side of the housing for azimuthal projection. The projector face can be viewed by at least one window opening provided on the front side of the housing and the projector is arranged outside of the viewing range between the window opening and the projection face. The projector has a projection axis which is disposed at an angle with respect to the optic axis of its lens. The projector is especially suitable for both indoor and outdoor use.

Abstract: A pocket-sized microform reader is realized by employing a unique lenticular (screen) assembly and a projection lens assembly, the latter permitting a fold in the middle of an optical path allowing the size requirements of such a reader to be met. The cooperation between the lenticular screen and the projection lens assemblies permits sufficient brightness to be obtained and the lenticular screen assembly defines a non wasteful exit pupil of limited dimensions consistent with a pocket-sized reader.

Abstract: A table for use in teaching children, particularly those with learning disabilities. The table includes a translucent top upon which a paper worksheet can be placed. An optical projector is mounted below the table top to direct an image onto the translucent table top. The image is seen through the paper worksheet and may be followed or traced by the child to develop psychomotor brain patterns.

Abstract: A film projection device having a screen, light source, lens and mirror system and a reference indicator disposed immediately in front of the mirror for shadow casting a reference line onto the image of a film projected onto the screen via initial projection onto the mirror.

Abstract: An optical device for a micro-image viewer or a micro-image viewer-printer machine receives a projected image of an illuminated micro-image, adjusts the spatial disposition of the projected image in an image plane and transmits the adjusted projected image to a viewing screen for viewing or to an exposure station for reproduction purposes. The optical device, in a preferred embodiment, includes a pechan prism positioned in a micro-image viewer-printer machine for receiving a projected image from a projection lens assembly. The pechan prism is rotatable about the illumination path or optical axis of the viewer-printer machine to enable the spatial disposition of the projected image to be rotated at least from 0 degrees to 180 degrees in an image plane.

Abstract: An improved display device utilizes an electro-optical panel including an electrically insulating layer and a light-modulating layer of dipole, light control particles dispersed in a transparent matrix. An imaging electric charge pattern is impressed on the panel to establish a particle orienting field thereacross. The light modulating pattern thus created in the modulating layer is selectively changed between positive and negative image sense by selective application and removal of a uniform field of the same polarity as, but lesser magnitude than, the imaging charge pattern. The stored image pattern is erasable by application of a reverse polarity field. Preconditioning the panel with a uniform field facilitates a positive light modulating pattern in the first instance.

Abstract: An optical system for use in a microfilm reading and printing apparatus which includes two reflecting mirrors for selective projection of light image from a microfilm onto an observation screen and a printing section within the apparatus. The two reflecting mirrors are driven in such a manner that they direct the image light from the microfilm onto the observation screen during reading, while the first reflecting mirror directs the image light from the microfilm toward the printing section during duplication, with the second reflecting mirror being turned away from the light path between the first mirror and the printing section, thus amount of rotation of the reflecting mirrors, especially of the first reflecting mirror being minimized for effective utilization of the limited space within the apparatus housing.

Abstract: A microform viewer for use with a rigid frame, the viewer having a housing pivotal about a longitudinal pivot axis and an end transverse pivot axis, a microform projector mounted on the upper surface of the housing and projecting a microform image downwardly along a projection axis, a viewing screen mounted in an opening in the upper surface of the housing, a reflector connected to the housing and reflecting the microform image upwardly onto the viewing screen, and rotation means connected between the housing and the frame for pivoting the housing about the longitudinal pivot axis and the end transverse pivot axis.

Abstract: A shopping aid display viewer having a housing that supports a daylight viewing screen, a second viewing area, and a slide projector for projecting images onto the daylight viewing screen. Purchasable items such as wearing apparel, gifts, notions, accessories, athletic equipment, real estate, visitor attractions, or any particular product or service that one may wish to advertise are sequentially displayed automatically or manually on the viewing screen. Outlets displaying the items or services are simultaneously shown on the second viewing area as a map locator guide. An automatic telephone dialing device can then be actuated to contact a specific outlet or location if the viewer user so chooses.

Abstract: A film reader include a lower casing accommodating a light source and an optical illuminator, and an upper casing enclosing a reflection type screen, the upper casing being collapsible and having an opening for observing the reflection type screen. A filter is disposed in the opening. One end of the filter is pivotably mounted to the upper casing and the other end of the filter is detachably mounted.

Abstract: A spherical shell mounted on a base for pivoting movement about a diameter has a first aperture in which a frosted groundglass screen is mounted parallel to the pivot axis. Images are sequentially projected on the screen from the vertically upright beam of a cassette-type sound projector by a deflecting mirror. Cassettes are inserted in and withdrawn from the projector through a second aperture subjacent the first aperture. The perforated cover normally closing the second aperture carries the loudspeaker of the sound system. Cooling air is blown on the projector lamp from bottom openings of the shell by a fan arranged between the shell and a bracket on which the projector rests.

Abstract: A box-shaped projection screen unit is attachable to an optical projector to constitute a cover therefor. The screen unit comprises a translucent screen mounted in an opening formed through the side of the box opposite an open side of the box which mates with the projector. A rectangular plate hinged to a vertical edge of the box has an internal reflecting surface facing the screen, and is swingable from a storage position covering the screen outward to a projection position in which the plate forms an angle with the screen. A triangular cover plate is hinged to the top edge of the box, and is swingable from a storage position between the rectangular plate and the screen outward to a horizontal position in which another edge of the triangular plate engages with the rectangular plate to hold the same in the projection position and prevent incident light from above from reaching the screen.