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: A lamp changing system is an LCD projector, comprising a reflective facet, a rotary plate having a plurality of arc-tubes and blocks disposed thereon, and a cam member having an upper cam and a lower cam, whereby upon rotating the cam member, an old arc-tube is separated from and new arc-tube is replaced for the old arc-tube as a light source for the LCD projector.

Abstract: A liquid crystal display projector combined with a video printer is capable of copying a desired picture being displayed on a screen as a photograph. The combination of a liquid crystal display projector and a video printer has a projection optical system including a concave mirror, an LCD panel, a projection lens, and a partial reflective mirror provided between the LCD panel and the projection lens. A copier optical system is also included which has a total reflective mirror, a copier lens, an LCD shutter, and photographic film on which an image signal passing through the partial reflective mirror is formed. A control circuit supplies a video drive signal to the LCD panel and a shutter output control signal to the LCD shutter when a copy selection signal is applied to the control circuit. Still picture data are outputted and applied through the LCD driver to the LCD panel so that the image passing through the copier lens is formed on the photographic film.

Abstract: A real time distance sensor for measuring distance by calculating the position of image of reflected laser beams with an extremely high-speed, includes a detection module containing a light receiving lens, an infrared ray filter, a CCD sensor, a lens system, and a laser; and a processing module containing a comparator, a differentiator, a pulse shaping circuit, a T flip-flop, a counter, a latch circuit, a ROM for calculation of distance, and power control and a D/A converter wherein the lens system contains cylindrical form for maintaining the intensity of laser beams with the travel of the beams.

Abstract: A stereoscopic television broadcasting system is provided which can televise the stereoscopic broadcasting of the left video and right video through two channels at the broadcasting station by inserting stereoscopic program data, left/right data and frequency data into the vertical retrace line intervals of the left video signal and the right video signal. A stereoscopic television receiver is provided which can display a stereoscopic picture thereon according to the broadcasting system, which includes a data separator for separating information data from the output signal of a tuner and outputting frequency data, stereoscopic data and left/right data therefrom, a tuning controller for generating a channel selection signal from the frequency data, a stereoscopic program data identifier and a right data identifier each for identifying the stereoscopic program data and left/right data of the separator, and an auxiliary circuit.

Abstract: A front projection screen includes front and rear refractive facets. The rear refractive facets are coated with refractive coating layers for reflecting an image light which has penetrated through the front refractive facets toward the front refractive facets. Upper and lower flanks are disposed at both upper and lower side surfaces of the rear refractive facets. Penetrative coating layers are formed on the lower flanks. A light-absorbing member is disposed between the penetrative coating layers and the upper flanks so as to absorb the illumination light (noise light).

Abstract: A rear projection screen having a wide-ranged extinguishing rate in which an area of portion for extinguishing the illumination light from exterior of the rear side of screen is widened so that the high contrast can be maintained, which includes a first sheet formed with Fresnel's lens and a second sheet having primary cylindrical lenticules at one side surface and secondary cylindrical lenticules at the other side surface, wherein a focus distance of the primary cylindrical lenticule is made to n/S1(n- 1) and the focus distance thereof is set larger than the distance between the top point of the primary lenticule and the center point of the secondary lenticule whereby clear pictures on the screen can be obtained without lowering the contrast even under an illumination light from exterior.

Abstract: Present invention employs two separate optical systems for left and right view images to be separately projected onto a screen for display by meams of respective light sources in the way of beaming a left view present image on the right view past image just prior displayed, and vice versa, to effect 3-D image and upgrade the brightness of the picture in display.

Abstract: An automatic focusing system adjusts the focus of video camera automatically using the contrast of the Y signal, which is one image input signal. The maximum and minimum values of the Y signal determine the contrast of the Y signal. This contrast value is then compared with the previous contrast value to determine if the focus driving motor should be signalled to rotate in the same direction as previously, a different direction or to stop rotation. Gating means with stored ranges are used to establish the successive detection of the Y signals to allow continuous operation of the auto focus circuit. Thus, the system can always automatically focus without being affected by the peripheral background of object.

Abstract: A device for winding a cord having upper and lower guide plates, each having a longitudinal guide slot. Slide knobs mounted on the guide plates each have transfer guide slots. Winding rods are slide-mounted in each transfer guide slot and extend through the longitudinal guide slots of the upper and lower guide plates. As the slide knob slides along the guide plates, the winding rods slide along the longitudinal and transverse guide slots to form a zig-zag arrangement for winding a cord thereabout.