Sony Corporation

Tsutomu Niimura

Masayuki Hongu

Kyoichi Murakami

Akira Yamakoshi

Mitsuru Sato

Hiromi Kawakami

Toshiaki Isogawa

Ryuji Shiono

Joichi Sato

Tatsuo Inoue

Makoto Natori

Yoshio Ishigaki

Takao Tsuchiya

Makoto Onga

Masaru Fujiwara

A liquid crystal display and a light source apparatus capable of improving color reproduction compared to related arts without declining intensity. A light source apparatus includes: a cold cathode fluorescent tube including a B phosphor for blue and a G phosphor for green; and a light emitting diode for red, wherein the G phosphor emits a single-spectrum light with a peak wavelength of 510 to 530 nm, and the light emitting diode emits a single-spectrum light with a peak wavelength of 620 to 650 nm.

Light source apparatus and liquid crystal display

In a camera device, the pixel numbers of an imaging device are selected to be greater than the largest number of pixels necessary for the generation of video signals of different aspect ratios and television standards. Output signals of the imaging device are stored in a memory and are then are selectively output. As a result, common use of an imaging device is permitted for camera apparatuses of, for instance, the NTSC, and other standards.

Camera apparatus for forming a plurality of different kinds of pictures

An automatic exposure control type video camera is designed to cope with the problem of deterioration in the image quality, for an object of higher brightness, by an arrangement in which a diaphragm is actuated when the brightness of the object light is below a predetermined threshold value, and in which the shutter speed is changed when the brightness of the object light is above the predetermined threshold value. More particularly, when the brightness of the object light is below a predetermined value, the shutter speed is set so as to remain constant and rotary diaphragm vanes, for example, are actuated mechanically to control the opening size of the diaphragm to limit the volume of incident light on the image sensing device. Conversely, when the brightness of the object light exceeds a predetermined value and the opening size of the diaphragm vanes reaches a predetermined value, the diaphragm is set so as to remain constant and the shutter is actuated to control the exposure time of the image sensing device to limit the incident light volume.

Video camera

A video signal inverting circuit, wherein a pedestal level of an output signal is selectively changed between a posi-mode and a nega-mode. The pedestal level of the output video signal is set equal to the pedestal level of the posi-mode output video signal in the nega-mode in accordance with a nega-mode/posi-mode control signal. In spite of the nega-mode/posi-mode control signal, a level setting circuit for the posi-mode is used during horizontal blanking period in the nega-mode.

Video signal inverting circuit

A circuit having a nonlinear response characteristic provides gamma compensation to a video luminance signal and matches any desired output response curve by selecting the number of diodes connected as series-connected circuits in the compensation circuit. The relationship among the various numbers of series-connected diodes is dependent upon having a current flowing into an output circuit which is the same as a current flowing out of a collector circuit of a differential amplifier, to which the input video luminance signal is applied, and through series-connected diode circuit. These currents are maintained equal by use of a current-mirror circuit, which provides an input current to an output transistor that has in its emitter circuit one of the series-connected diode circuits, and the compensated luminance signal flows in the collector circuit thereof. The differential amplifier is stabilized and balanced by a difference amplifier connected in feedback across the collector leads of the differential amplifier in conjunction with a pedestal clamping synchronization signal and a capacitor to provide a balancing signal at the base lead of the second transistor of the differential transistor amplifier.

Gamma compensating circuit

A signal converting circuit for converting a single-ended input signal to a pair of differential output signals includes a current source for generating a constant current; an input signal generating circuit for generating an input signal current; a first path including at least one diode connected to the current source and the input signal generating circuit for producing a first differential current as a function of the constant current and the input signal current; a second path including a series combination of a diode and the collector-emitter path of a transistor connected to the current source and the input signal generating circuit for producing a second differential current as a function of the constant current and the input signal current, the transistor being supplied with a current at its input; a differential amplifier output circuit having two transistors connected to the first and second paths for producing differential output signals in response to the first and second differential currents; and a circuit for eliminating the effect on the differential output signals of the current at the input of the transistor, the circuit for eliminating including a transistor having its collector-emitter path connected between the first path and ground and a diode connected between the second path and ground.

Circuit for converting single-ended input signals to a pair of

A signal converting circuit, which has particular application as a pedestal clamp circuit for a video signal, includes a differential amplifier having a pair of transistors which produce first and second differential currents at the respective collectors thereof; a first circuit supplied with the first differential current and including a diode and a first resistor having a first resistance value connected in series between the collector of one of the transistors of the differential amplifier and a reference potential; a second circuit supplied with the second differential current and including a second resistor having a second resistance value and a transistor having its collector emitter path connected in series with the second resistor between the collector of the other transistor of the differential amplifier and the reference potential; and an output circuit for producing an output current in response to the second differential current and including a current mirror transistor having its base-collector path connected in parallel with the collector-emitter path of the transistor of the second circuit, wherein the current gain of the signal converting circuit is controlled by the resistance values of the first and second resistors.

Circuit converting a pair of differential input signals to single-ended

A chrominance signal processing circuit for generating a gain-controlled chrominance signal carrier and a phase-controlled burst signal is provided with a first differential amplifier receiving a chrominance signal carrier and having a first constant current source, a second differential amplifier receiving an output signal of the first differential amplifier, a phase control circuit connected to the output of the second differential amplifier, the second differential amplifier receiving its bias current from a second constant current source during a chroma interval and from a third constant current source during a burst interval, the ratio of the currents of the first and second constant current sources being controlled for controlling the gain of the chrominance signal, and the output of the second differential amplifier being controlled at least during the burst interval, for controlling the phase of the burst signal.

Chrominance signal processing circuit

A circuit that is particularly adapted to convert a single-ended input signal to a pair of differential output signals. First and second series circuits are connected in parallel, the first series circuit being formed of first and second diodes and the second series circuit being formed of a third diode connected with the collector-emitter circuit of a transistor. The base electrode of the transistor is connected to the junction defined by the first and second diodes such that the base-emitter circuit thereof is in parallel arrangement with the second diode. A current source is connected to the parallel-connected series circuits so as to supply currents thereto. An input signal is supplied to the junction defined by the first and second diodes; the first and second outputs are coupled to this junction and to the collector electrode of the transistor, respectively, for providing differential output signal currents that are a function of the supplied signal. This circuit can be connected to a differential amplifier to supply differential signals to the latter, whereby a gain controlled amplification of the original single-ended input signal can be attained.

A tuner for receiving signals broadcast on two spaced bands, each divided into several channels, has two fixed bandpass filters, one to pass all of the channels in the lower frequency band and the other to pass all of the channels in the higher frequency band. The tuner includes a mixer to which signals of either band are supplied by selective operation of a double-throw switch. A tunable local oscillator supplies a heterodyning signal to the mixer to convert any selected channel of the received signal to an intermediate frequency (i.f.) band chosen to avoid image interference from undesired channels, whether the local oscillator frequency is above or below the selected channel. To ease the constraints on the choice of the i.f. band, different i.f. filters tuned to first and second i.f. bands may be used for the higher and lower received bands. A second double-throw switch ganged with the first switch can then be used to direct the heterodyned signals to the proper i.f. filter.

Multi-band tuner with fixed broadband input filters

A tuner for receiving signals broadcast on two spaced bands, each divided into several channels, has two fixed bandpass filters, one to pass all of the channels in the lower band between the lowest frequency f.sub.P of the lowest channel and the highest frequency f.sub.S of the highest channel of the lower band, and the other to pass all of the channels in the upper frequency band between the lowest frequency f.sub.T of the lowest channel and the highest frequency f.sub.W in the highest channel of the upper band. The bandwidth of each channel is f.sub.B. The tuner includes an amplifier and a third filter to which signals of either band are supplied by selective operation of a switch. The third filter has a cut-off frequency below the second harmonic of the lowest frequency of the upper band to simplify the avoidance of image interference from second harmonic signals of the band. A tunable local oscillator supplies a heterodyning signal to the mixer to convert any selected channel of the received signal to an intermediate frequency (i.f.) band, and image interference is avoided by setting the local oscillator frequency f.sub.n required to convert channel n to the i.f. at a frequency above that channel such that the lowest frequency f.sub.L of the i.f. band satisfies the following conditions: ##EQU1##

Multi-band tuner

In apparatus for reproducing color video signals recorded in successive parallel tracks on a record medium with the chrominance components of video signals recorded in next adjacent tracks having first and second carriers which differ from each other in respect to their phases or polarity characteristics; and in which a plurality of transducers scan along the tracks one at a time so as to reproduce the video signals recorded in each of said tracks along with cross-talk signals from the tracks next adjacent thereto, means for separating said chrominance signal components from the luminance signal component in the reproduced signals, and a signal processing circuit including a switching circuit and a comb filter provides the separated chrominance components of video signals reproduced from each of said tracks with a common carrier and eliminates therefrom the chrominance components of the cross-talk signals on the basis of said different phases of the first and second carriers with which the chrominance components were recorded in the tracks which are next adjacent to each other: the changing-over of the switching circuit is controlled in response to the phase of the chrominance component carrier that results therefrom so as to ensure phase alignment of the common carrier with which the chrominance components of the video signals reproduced from the successive tracks are provided. Further, control signals are recorded on the record medium to identify those tracks in which video signals are recorded with their chrominance components having said first and second carriers, respectively, and, on reproducing, such identifying control signals are reproduced to control the movements of the transducers and, through such controlled movements, to regulate the changing-over of the switching circuit.

Apparatus for recording and/or reproducing color video signals

An automatic gain control circuit for a video signal amplifier to integrate the synchronizing pulse portion of the composite signal and apply the integrated signal to a pulse generating circuit to generate a pulse each time the integrated signal exceeds a certain level. The pulse, which has a fixed magnitude, is added to the amplified video signal in the same polarity relative to the blanking level as the luminance signal. A control circuit measures the peak-to-peak value of the combined signal and generates a controlling signal having a magnitude that varies with changes in the peak value and is used to control the gain of the amplifier.

A.G.C. circuit for a video signal

A high-frequency modulator circuit including a frequency multiplier comprised of a first differential amplifier for receiving a base oscillating signal and for multiplying the frequency of the base oscillating signal to thereby produce a higher frequency carrier signal; and a modulating circuit connected to the first differential amplifier for modulating the carrier signal with input information. The first differential amplifier includes a pair of output terminals; and the modulating circuit is comprised of a second and third differential amplifier, each having a pair of input terminals connected to the respective output terminals of the first differential amplifier such that the higher frequency carrier signal is applied differentially to each of the second and third differential amplifiers. The second and third differential amplifiers each includes a pair of output terminals, the second differential amplifier output terminals being connected to oppositely phased ones of the third differential amplifier output terminal. The input information is supplied to at least one of the second and third differential amplifiers to thereby vary the higher frequency carrier currents which flow therethrough.

High frequency modulator, such as an amplitude modulator, including a

A signal to be controlled is applied to the base of an emitter-follower input transistor, the emitter of which is connected to an input terminal of a differential amplifier. This input terminal of the amplifier is connected by a diode to a controllable current source so that the base current of the differential amplifier input transistor is controlled. A constant current source is connected to the common emitter circuit of the differential amplifier, and the gain of the circuit is determined by the ratio of current in the latter source to current in the controllable source. A current conducting circuit, such as, an emitter load resistor, is connected to the emitter of the input transistor to hold the output impedance thereof at a substantially constant low value inspite of changes in the current of the controllable current source, Maximum gain of the circuit may be determined by separating the controllable current source into a controllable portion and a fixed portion in parallel so that the minimum current is at least as great as the current of the fixed portion. This limits the maximum circuit gain by limiting the maximum ratio of fixed current to controllable current. A fixed voltage source connected to the common circuit point between the controllable current source and the diode assures that the gain of the circuit will not fall below a selected minimum value.

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Hiratsuka, Japan

Tsutomu Niimura