Abstract: In order to enable sampling of high definition still video signals in addition to common video signals, a function is added for sampling video signals with every other plurality of picture elements as an interval to an image processing apparatus without using a sampling circuit which requires high speed operations. The invention is also intended to change over between two circuits that is, a circuit for using a picture element clock regenerated by a PLL circuit as a sampling clock for analog to digital converters and a circuit for using a clock obtained by dividing the picture element clock as a sampling clock for the analog to digital converters to sample video signals with every other plurality of picture elements as an interval. Thus, it is possible to carry out sampling of high definition video signals with high frequencies in addition to common video signals without necessity of raising the operating speed of the sampling circuit.

Abstract: A liquid crystal projection display capable of functioning at a high light capturing efficiency and a high relative corner illuminance comprises a light source means including a light source, a liquid crystal panel means, a projection lens means and a screen means. A liquid lens formed by sealing a liquid in a space between opposite transparent members is disposed near the light source or the real image of the light source to enhance the relative corner illuminance without reducing the light capturing efficiency by multiplying the angle of divergence of light rays emitted by the light source by the reciprocal of the refractive index of the liquid. A first optical system disposed on the entrance side of the liquid crystal panel is provided with a relative corner illuminance enhancing means comprising a first light converging means disposed relatively near to the light source means, and a second light converging means disposed relatively remote from the light source means.

Abstract: A multi-scan type display apparatus with pointer function includes a multi-scan type display unit for displaying a plurality of kinds of main picture signals having different numbers of scanning lines and a pointer position identifying signal generating circuit for generating a pointer position identifying signal. The pointer position identifying signal generating circuit transfers the pointer position identifying signal to the multi-scan type display unit, the multi-scan type display unit includes a universal vertical position address signal generating circuit, a horizontal position address signal generating circuit, a pointer signal generating circuit and a superimposing circuit.

Abstract: A multi-screen projector having unit module projectors stacked at two higher and lower stages, each unit module projector having a screen with a Fresnel sheet unit, a prism sheet unit, and a lenticular sheet unit. By the functions of the Fresnel sheet unit and the prism sheet unit, main output light from higher and lower screens is converged to substantially the same target point. Only one type of metal molds is required for the Fresnel sheet unit as well as the prism sheet unit, thereby reducing the manufacturing cost of the multi-screen projector.

Abstract: For the purpose of detecting a geometric distortion of an image on a screen of a CRT display device, i.e., the deviation of the positional coordinates at a high speed and with a high accuracy, the positions of window images having about 10 rows and 10 columns which are arranged in a matrix on the screen of the display device, including a screen frame, are photographed through a predetermined low-pass filter by a monochromatic CCD camera, and further, both the low-light field picture and the high-light field picture are photographed, whereby the positions of the window images can be detected with a high accuracy within 0.1 CCD pixel by the elimination of a dark current, the normalization of detection sensitivity and the interpolation calculation. Therefore, the detection of the geometric distortion can be performed at a high speed and with a high accuracy by an inexpensive monochromatic CCD camera which has the number of pixels less than the total number of pixels of the display device.

Abstract: A uniformity correction signal generating apparatus includes a horizontal address signal generating unit and a vertical address signal generating unit for generating address signals (X) and (Y, y) having one-to-one correspondence to a position on a display screen of a display unit, respectively. Upper and lower adjacent lattice point data are read out from an E.sup.2 PROM on the basis of the address signals X and Y. Interpolated correction data are obtained on the basis of the upper and lower lattice point data and vertical lower address coordinates y. The apparatus is suitable for an auto-scan type display unit and can correct the uniformity for gradation and focus by using the inexpensive E.sup.2 PROM without need of a large capacity expensive E.sup.2 PROM.

Abstract: A projection type display device including a CRT with a fluorescent layer and a face glass for projecting an image reflected onto the fluorescent layer through the face glass, a transparent liquid, at least one lens element and onto a screen. The transparent liquid is filled within a space between the face glass of the CRT and the at least one lens element and has a refractive index substantially the same as a refractive index of the face glass of the CRT and the at least one lens element. A light attenuation filter having a transmittance no greater than 0.9 is disposed at a position from the fluorescent layer to the at least one lens element such as between the face glass and the at least one lens element.

Abstract: An adaptive crosshatch signal generator includes a frequency detector for detecting a horizontal scanning frequency, a square calculator supplied with the detected output of the frequency detector, and a variable pulse width multivibrator controlled to have an output pulse width substantially in inverse proportion to the squared output. Longitudinal lines of a crosshatch signal are formed by the output pulses of the multivibrator. The crosshatch signal has a longitudinal line width which is always substantially equivalent to the distance between adjacent scanning lines and is generated by using a simplified configuration irrespective of input signal format.

Abstract: A screen is constituted by one sheet of Fresnel lens and two sheets of lenticular lenses, and the following relationships are fulfilled: 0.9 To<vy.multidot.dy/n and 0.9 To<vx.multidot.dy<3 To where vx and vy denote respectively angles, which are obtained when viewing a projection lens from the side of the lenticular lenses through the Fresnel sheet, dx and dy denote respectively distances between a surface of the Fresnel lens and focal planes of the lenticular lenses, n denotes a refractive index of a medium, and To denotes a pitch of the Fresnel lens, whereby radial two dimensional moire disturbance appearing in a rear projection display can be reduced to one-fifth the amplitude of the prior art one.

Abstract: A liquid crystal projection display capable of functioning at a high light capturing efficiency and a high relative corner illuminance comprises a light source means including a light source, a liquid crystal panel means, a projection lens means and a screen means. A liquid lens formed by sealing a liquid in a space between opposite transparent members is disposed near the light source or the real image of the light source to enhance the relative corner illuminance without reducing the light capturing efficiency by multiplying the angle of divergence of light rays emitted by the light source by the reciprocal of the refractive index of the liquid. A first optical system disposed on the entrance side of the liquid crystal panel is provided with a relative corner illuminance enhancing means comprising a first light converging means disposed relatively near to the light source means, and a second light converging means disposed relatively remote from the light source means.

Abstract: A video output circuit of a wide bandwidth comprises a bridged-T-type circuit, a first inductor connected in series to the bridged-T-type circuit, and a shunt circuit connected in series to the bridged-T-type circuit and including a second inductor and a first resistor connected in parallel with each other. The bridged-T-type circuit, the first inductor and the shunt circuit cooperate to constitute together with a plurality of stray capacitors a low-pass filter whose order is at least 4 and whose merit index is at least 3.

Abstract: A focus yoke used for an electromagnetically focused CRT display comprises: a cylindrical permanent magnet unit which is disposed around a neck portion of a CRT and is spaced from the circumference of the neck portion; a core unit which defines a toroidal space together with the cylindrical magnet unit for substantially surrounding the neck portion, the core unit forming a magnetic path to guide magnetic lines of force generated by the cylindrical magnet unit; a dynamic focus winding unit disposed in the toroidal space; and a winding unit disposed externally of said toroidal space for eliminating an undesired magnetic field of an inverse polarity generated due to the cylindrical magnet unit.

Abstract: Apparatus for a multi-screen display including a multiprocessor for processing signals from at least one signal source and for applying processed signals to a plurality of display units arranged in at least two rows so as to form the multi-screen display. The multiprocessor includes vertical scanning format transformation apparatus for transforming a vertical scanning frequency of the output signal of the multiprocessor to be a higher vertical scanning frequency than that of a vertical scanning frequency of the input signal of the multiprocessor so that a ratio of the vertical scanning frequency of the output signal applied to the multi-screen display to the vertical scanning frequency of the input signal is at least two, thereby substantially eliminating discontinuity distortion of a moving pole image displayed as a reproduced picture on the multi-screen display.

Abstract: It is an object of the invention to provide a large-screen projection type display capable of reducing the moire interference due to the periodical structure of the linear Fresnel lenses and lenticular lenses. Since the moire interference is attributed to the shades S generated from the Fresnel sheet 1, these shades are diverged at a divergence angle .epsilon. by the action of the small-pitch lenticular lenses 4, so that the shades can be eliminated on the light-incident side surface of the lenticular sheet 3 which is located at a distance D from behind the Fresnel sheet.

Abstract: The object of the invention is to provide a large-screen projection-type display using a transmission-type screen, wherein the transmission-type screen is formed of two or more sheets 4, 7, is tilted toward the viewer's side with a small gap kept between the sheets, and is stable relative to the temperature and moisture change of the environment. The front sheet 4 provided on the viewer's side and the Fresnel sheet 7 provided on the projection source side are tilted forward by about 7.degree. toward the viewers. The springs 10 are extended through wires 9 to exert the tension on the front sheet 4 in the vertical direction. At the same time, the springs exert a pressure on the Fresnel sheet 7 in the vertical direction.

Abstract: A digital convergence correction circuit for a CRT display unit deals with the problem of an excessive calculation time of the microprocessor expended for the vertical interpolation by using at least two pieces of ROM (read only memory) devices connected together. The circuit deals with the problem of a step variation of brightness by employment of a novel slope interpolation means which implements interpolation based on a continuous waveform of the first-order differential coefficient at the lattice points of the display screen and a curve interpolation means which forms a more superior convergence system. The circuit uses a blanking means to prevent abnormal states from appearing on the display screen during the transfer period of the digital convergence correction data of a new format at the switching of the scanning format for a video signal to be displayed.

Abstract: A video output circuit for driving a CRT of a grid-cathode differential drive type is disclosed, in which a collector potential of an output transistor in a horizontal blanking interval is detected by a diode arrangement; the potential thus detected is smoothed by a smoothing filtering arrangement output current of the output transistor is controlled by an output obtained by the smoothing filtering arrangement; and negative feedback control is effected so that the collector potential of the output transistor is made constant. In this way, a bias adjusting power supply, which was required heretofore, is made unnecessary.

Abstract: A projection display of the type which projects the respective images emitted from a plurality of tubes on a rectangular screen through lenses arranged correspondingly to the projection tubes, thereby to compose the images by overlapping, wherein the lenses are arranged so that the optical axis is located on the center line substantially bisecting the angle at which the pupil of each of the lenses sees both side ends of the rectangular screen with an equal angle, and wherein there is provided an arrangement for optically or electrically correcting relative deviations in the amounts of light projected from the lenses.

Abstract: A support member for supporting a plurality of vertically-arranged Fresnel sheets is fixedly mounted on a lower end portion of a reinforcing sheet. A hanging mechanism hangs the reinforcement sheet and the Fresnel sheets vertically adjustably. An elongated screen is constituted by a plurality of vertically-arranged unit screens, and the overall screen is constituted by a plurality of elongated screens arranged horizontally. A mechanism for preventing the relative displacement of the opposed edges of the elongated screens from each other in a direction perpendicular to the plane of the elongated screen is provided at an effective projection light-absent region where the light projected from projectors onto the screen is not hindered. A mechanism for limiting the absolute displacement of the elongated screens in a direction perpendicular to the plane of the elongated screen is provided at the right and left edges of the elongated screens and is disposed at the effective projection light-absent region.

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