Abstract: A horizontal deflection circuit which including a horizontal output transistor; a damper diode connected in parallel with the horizontal output transistor; a resonant capacitor connected in parallel with the damper diode; a horizontal deflection coil connected in parallel with the horizontal output transistor; and a series resonant circuit connected in parallel with the resonant capacitor. The series resonant circuit is constituted by a series connection of a capacitor and an inductor to perform composite resonance in cooperation with the resonant capacitor. The capacitor and the inductor of the series resonant circuit are designed to have a tertiary resonant frequency. The composite resonance by means of the series resonant circuit and the resonant capacitor enables the top of the flyback pulse to be flattened, so that the waveform of the flyback pulse becomes near the form of rectangular wave.

Abstract: A rear projection apparatus is disclosed which is provided with at least two optical projection lens units. Two or more projected images are joined to form a single projected image on a screen. A light reflection preventing member is provided on a blocking plate for preventing the adjacent images from overlapping with each other. The reflection preventing member is used for preventing the light, projected onto the blocking plate, from being introduced into the screen, thereby preventing a degradation of contrast.

Abstract: A convergence apparatus in which a sawtooth wave signal having a horizontal period is modulated by a sawtooth wave signal having a vertical period and supplied to a convergence coil to correct misconvergence of rasters on the projection screen, characterized in that the sawtooth wave signal having the horizontal period is derived by integrating a pulse advanced in phase as compared with the flyback pulse by a PPL circuit and hence the distortion of the sawtooth wave signal having the horizontal period exists within a horizontal blanking period.

Abstract: An AGC circuit used in a subscriber's receiver of a CATV system in which the television signal is scramble-modulated so that only subscribers are allowed to view toll programs, wherein the detected video signal is conducted through a low-pass filter to extract the vertical sync signal, a keying pulse is produced in response to the vertical sync signal, and the AGC operation is performed by the keying pulse in accordance with the magnitude of the vertical sync signal.

Abstract: In a video projector for projecting a video picture displayed on a Braun tube, the space between the Braun tube and a lens is filled with a medium having a refractive index substantially equal to those of both the glass faceplate of the braun tube and the material of the lens, and the medium is a silicon resin of the mixture of two liquids which is in liquid phase just after the mixing of two or three or above liquids but cured after lapse of a certain time into a gel state, and the lens is supported by a lens holder so that it can be moved freely along the optical axis within the lens holder.

Abstract: A television system employing the sequential scanning system wherein picture information obtained by sequential scanning at a scanning frequency twice that of the standard system in separated into the first field information consisting of odd-numbered lines and the second field information consisting of even-numbered lines, and the separated field informations are stored in respective memory devices. The first and second field informations stored in the memory devices are transmitted separately by a transmitter. The first and second field informations received by the reception system are stored in separate memory devices. The first and second field informations are read out from the memory devices in the order of the odd-numbered line and then the even-numbered line at a speed twice the writing speed, and the read-out line information is displayed on a display device which scans sequentially the screen at a scanning frequency twice that of the standard system.

Abstract: In a video projection apparatus including a projection lens, a cathode-ray tube and a projection screen, a layer of a medium whose refractive index n.sub.p decreases with a temperature rise is disposed between the projection lens and the faceplate of the cathode-ray tube, and the thickness l.sub.p of the medium layer is selected to substantially satisfy the following equation thereby compensating the temperature-dependent variation of the focal length of the principal lens: ##EQU1## where .DELTA.T is a temperature variation; .DELTA.n.sub.p is a variation of the refractive index n.sub.p due to the temperature variation .DELTA.T; f is the focal length of the projection lens; K is a constant representing the proportion of the power of plastic lenses to the total power when the projection lens is of a hybrid type; .DELTA.f is a variation of the focal length f due to the temperature variation .DELTA.T; and M is the magnification of projected images.

Abstract: In accordance with the present invention, there is provided an image projection apparatus comprising: a concave radiant plane for forming an original image, the radius of curvature of the concave radiant plane being one unit of length; a transparent medium layer having a refractive index of n, where n>1; a convex light exit plane having the radius of curvature of approximately n units of length, the convex light exit plane being placed forwardly in the normal direction of the radiant plane at a distance of approximately (1+n) units of length therefrom; the transparent medium layer having the refractive index of n filling substantially the space between the concave radiant plane and the convex light exit plane; and a vertex angle .theta..sub.3 of the diverging light emitted from the light exit plane being .theta..sub.3 =sin.sup.-1 (1/n.sup.2).

Abstract: A rear projection apparatus for displaying a color image including red, green and blue color image sources located horizontally to each other in this order for producing respective color images of different colors. Projection lenses are located respectively in front of the image sources for projecting light flux of the respective image sources along converging optical paths, and a screen is located at convergent points of the projected light fluxes. The screen includes a light-transmitting lenticular sheet having an input surface and an exit surface wherein the input surface is constituted by horizontally diffusing lenticular profiles having a ratio of a lenticulated depth X.sub.v to a close-axis-curvature radius R.sub.1 (X.sub.v /R.sub.1) which is within the range of 0.5 to 1.8, with the profiles being prolonged along the optical axis and constituting aspherical input lenticular lenses.

Abstract: A rear projection screen adapted for a rear projection type television receiver comprises a combined Fresnel and lenticular surface which exhibits both Fresnel lens action for macro-converging divergent input light rays and lenticular lens action for micro-diverging the input light rays.

Abstract: A rear projection apparatus for displaying a color image including red, green and blue color image sources located horizontally to each other in this order for producing respective color images of different colors. Projection lenses are located respectively in front of the image sources for projecting light flux of the respective image sources along converging optical paths, and a screen is located at convergent points of the projected light fluxes. The screen includes a light-transmitting lenticular sheet having an input surface and an exit surface wherein the input surface is constituted by horizontally diffusing lenticular profiles having a ratio of a lenticulated depth X.sub.v to a close-axis-curvature radius R.sub.l (X.sub.v /R.sub.l) which is within the range 0.5 to 1.8, with the profiles being prolonged along the optical axis and constituting aspherical input lenticular lenses.

Abstract: A recording/reproduction system is disclosed in which main information in the form of high-frequency signal is recorded in time sequence along a multiplicity of tracks adjacent to each other. A discrimination signal is superimposed on the high-frequency signal in advance for recording and has a different occupied frequency band for each adjacent track, whereby discrimination of lead or lag in track arrangement is accomplished. The difference of the discrimination signal between tracks may take the form of phase difference with the same frequency or signals of different frequencies.

Abstract: Disclosed is an automatic noise removal device which detects an amplitude of noise contained in a high frequency component of a picture signal during a flyback period of the picture signal, produces a threshold level depending on the detected signal, and removes from a video signal a high frequency component of the picture signal contained in a picture signal at a lower level than the threshold level.

Abstract: A discriminator apparatus for a television multivoice system comprises a mixer for mixing a program identifying signal with a reference signal thereby to produce a differential beat signal. A reference signal generator includes a signal source of an original frequency, and a frequency converter for converting the original frequency to the reference frequency which is close to the frequency of the program identifying signal and so selected that the frequency of the differential beat signal is lower than the lowest audible frequency. A low-pass filter is employed for extracting the differential beat signal. Need for expensive mechanical filters of a narrow fractional bandwidth is thereby eliminated.

Abstract: Disclosed is a crosstalk attenuator system for reducing the crosstalk which occurs at the time of separating and reproducing the original signals from the video disc recording medium on which a video signal and a voice signal have been recorded as a compound signal on the same track. In the system, a first multiplier receives both the signals separated from the medium to analyze the relative relation between the signals and thus to generate an output signal according to the amount of the crosstalk between the signals; a second multiplier receives the output signal and one of the signals to generate a feedback signal equivalent to the other crosstalk signal component mixed in one signal, and the feedback signal is subtracted from the other signal component thereby to reduce the crosstalk.

Abstract: In a television receiver having a peak value type AGC circuit for maintaining the amplitude difference between a carrier zero level and the peak value of a composite video signal amplified by a high frequency amplifier and a video intermediate frequency amplifier at a constant magnitude, an automatic brightness limiter (ABL) circuit is provided which controls the AGC circuit such that when the beam current exceeds a predetermined value and the carrier zero level approaches the peak value, a composite video signal of reduced amplitude is produced.

Abstract: Red, blue and green color difference signals are supplied to the bases of first, second and third transistors amplifying the tri-color signals of red, blue and green, and a luminance signal is introduced to the emitter of each transistor through a parallel circuit of two resistors. One of the resistors in each parallel circuit is connected through a switch. The switches are associatively operated so that the on-off operation of the switch connected to the emitter of the first transistor is opposite to that of the switches connected to the emitters of the second and the third transistor. By operating the switches, the amplification degree of the first transistor is increased and simultaneously the amplification degrees of the second and third transistors are decreased, and therefore an image with red emphasized can be obtained with no change in luminance.