Abstract: A diode modulator circuit which is adapted to supply an acceptable S-correction of the S-linearity error of the line scanning of a picture tube (CRT) at substantially different line scan widths. A known diode modulator has two loops. The first loop includes a series arrangement of a line deflection coil (LD) and an S-capacitor (CS), which series arrangement is arranged in parallel with a first flyback capacitor (CF1) and a first diode (D1). The second loop includes a modulator coil (LB) arranged in parallel with a second flyback capacitor (CF2) and a second diode (D2). The two loops are arranged in series. An inner-pincushion capacitor (CSM) is arranged in a common path in which the line deflection current (Id) and a modulator current (Ib) flowing through the modulator coil (LB) flow in opposite directions. The amount of S-correction depends on the values of the S-correction capacitor (SC) and the inner-pincushion capacitor (CSM). The S-capacitor (CS) has been omitted in the subject diode modulator.

Abstract: A control circuit (100) which receives horizontal synchronising pulses (265) and generates a horizontal drive output signal (455) for a cathode ray tube (CRT) display. The horizontal control circuit (100) generates two ramp signals. A first ramp signal (410) for horizontal position adjustment of an image on the CRT display, and a second ramp signal (440) for propagation delay compensation of a deflection circuit (155) coupled to the CRT display. The control circuit (100) also provides digital of control of the duty cycle of the horizontal drive signal (455).

Abstract: A non-switched, DC coupled vertical deflection circuit includes a source of a first DC supply voltage that is coupled to a first end terminal of a vertical deflection winding. An amplifier is energized by a second DC supply voltage having twice the magnitude of the first DC supply voltage and the same polarity. An output voltage of the amplifier having the same polarity of each of the first and second DC supply voltages is developed at a second end terminal of the deflection winding. The amplifier produces a deflection current at opposite polarities, during corresponding portions of a vertical trace interval.

Abstract: A CRT system is provided, preventing the resolution on a phosphor screen from degrading due to the characteristic or performance variation and/or deviation of an electron gun. The electron gun has cathodes for emitting R, G, and B electron beams. First and second focusing electrodes focus the electron beams onto a phosphor screen. A drive unit has a power supply for supplying first and second focusing voltages to the first and second focusing electrodes, respectively. The second focusing voltage is an ac voltage with a parabolic waveform. The first focusing voltage is a dc voltage generated by dividing the second focusing voltage with the use of a resistor. A difference between the first and second focusing voltages generates an electrostatic quadruple lens in a space between the first and second focusing electrodes.

Abstract: An apparatus and method to dynamically shape the projected energy profile of an electron beam and the energy distribution of an electron beam of a cathode ray tube to provide a single cathode ray tube the ability to display multiple image formats of varying resolutions, brightnesses and aspect ratios. In one embodiment, the invention contemplates the introduction of a shaping lens along the path of the electron beam comprising at least three electrodes. Voltages are selectively applied to the electrodes to dynamically and selectively vary the projected energy profile of an electron beam in a plane perpendicular to the longitudinal axis of the cathode ray tube.

Abstract: The present invention relates to a method and system for optimizing the output of at least two electron guns in a cathode ray tube for aging the cathode ray tube during manufacture. The system comprises at least two electron guns located in the cathode ray tube and a memory configured to store an offset value that is representative of a difference between a maximum output level and a detected output level for each of the electron guns. The system further comprises a processor coupled to the memory. The processor generates a first scaled signal by adding a first signal representative of an input voltage corresponding to the detected output level of the first electron gun and an offset signal representative of the offset value, and a second scaled signal by adding a second signal representative of an input voltage corresponding to the detected output level of the second electron gun and the offset signal.

Abstract: An apparatus and method are disclosed for generating timing pulses to control various functions in a video monitor including the switching of video amplifiers in cathode ray tube (CRT) devices, the control of the phase and frequency of phase locked loops, etc. Unlike previous methods, where switching is timed and controlled by monitoring the retrace voltage level, the system of the present invention monitors the change in direction of current in the retrace tuning capacitor. Monitoring the retrace capacitor current, provides an extremely accurate method for timing in horizontal deflection circuits. The apparatus of the present the invention comprises a small bead inductor placed in the current path of a horizontal retrace capacitor within the horizontal deflection circuit of the cathode ray tube device. Measuring the voltage across the bead inductor allows a very precise monitoring of the current through the retrace tuning capacitor.

Abstract: On a rear plate of a vacuum envelope are provided a plurality of electron guns for emitting electron beams to a phosphor screen, and deflection devices for deflecting the plurality of electron beams emitted from the respective electron guns so as to dividedly scan a plurality of regions of the phosphor screen by the electron beams. Each of the deflection devices has a horizontal deflection coil and a vertical deflection coil. The horizontal deflection coils of the deflection devices are connected to one another in series, and the vertical deflection coils of the deflection devices are connected to one another in series. All the deflection devices are driven by a common deflection driving circuit which has a horizontal deflection driving circuit connected to the horizontal deflection coils and a vertical deflection driving circuit connected to the vertical deflection coils.

Abstract: A deflection circuit generates a deflection current (If) through a deflection coil (Lf). The deflection circuit includes a series resistor (Rs) arranged in series with the deflection coil (Lf) to supply a feedback voltage (Vf;Vr), and a drive circuit (1,5) which has an output coupled to the series arrangement of the deflection coil (Lf) and the series resistor (Rs). The drive circuit (1,5) has an input coupled to the series resistor (Rs) to receive a feedback voltage (Vs). The drive circuit (1,5) further is coupled to a conversion resistor (Rc) for receiving an input waveform (Vi). The drive circuit (1,5) is arranged in a feedback loop to obtain a deflection current (If) with a shape resembling the input waveform (Vi). The deflection circuit further includes a damping impedance (Rd) arranged in parallel with the deflection coil (Lf), and a current generating circuit (3) for generating a correction current (Ic) within the flyback period (Tf).

Abstract: A dynamic focusing circuit for a monitor has a microcomputer which generates a mode control signal by determining a mode when inputting horizontal and vertical synchronization signals, and provides a dynamic focus signal to a focus grid of a cathode ray tube through a flyback transformer according to the mode control signal. A focus signal generation section generates horizontal and vertical dynamic focus signals according to the waveform control signal of the waveform control signal generation section and a waveform adjustment section adjusts a waveform of the dynamic focus signal of the focus signal generation section by inputting the mode control signal.

Abstract: The turn-off period of the FET (111) is adjusted by changing the output pulse width of the MM (113) according to the horizontal deflection frequency, to adjust the total capacitance value of the S-shape correcting capacitor group in one horizontal deflection period, that is, to execute an optimum S-shape distortion correction according to each horizontal deflection frequency. The timing at which the electronic switch element (111) is turned off in a first half of the horizontal scanning period is continuously and variably controlled on the basis of an external control signal (Vg). The auxiliary S-shape correcting capacitor (110) of the S-shape correcting capacitor group is controllably turned on or off by the electronic switch element (111), to execute an optimum S-shape distortion correction.

Abstract: An electron accelerator includes a vacuum chamber having an electron beam exit window. An electron generator is positioned within the vacuum chamber for generating electrons. A housing surrounds the electron generator and has a first series of openings formed in the housing between the electron generator and the exit window for allowing electrons to accelerate from the electron generator out the exit window in an electron beam when a voltage potential is applied between the housing and the exit window. The housing also has a second series and third series of openings formed in the housing on opposite sides of the electron generator for causing electrons to be uniformly distributed across the electron beam by flattening electrical field lines between the electron generator and the exit window.

Abstract: A horizontal deflection output circuit has a resonance circuit including a horizontal deflection yoke for generating the horizontal deflection signal, a first switch element, a second switch element comprising a bipolar transistor, and a circuit for applying a reverse bias voltage to the emitter-base junction of the bipolar transistor during a retrace period to remove excess minority carriers stored in its base rapidly, thereby making high speed switching operation of the transistor possible.

Abstract: Scanning lines are automatically shifted by using a test signal for detecting a screen display height, a detector which detects information of the screen display height from the test signal, a calculator which calculates a scanning-line shift amount, a moire correcting waveform generator which generates a voltage for shifting the scanning lines, and a deflecting device which deflects electron beams.

Abstract: A horizontal S-shaped correction signal circuit having a correction condenser disposed in a cathode ray tube (CRT) horizontal deflection circuit such as in a television receiver, a display monitor, etc. In particular, a horizontal S-shaped correction signal circuit which is capable of obtaining an accurate correction effect and a desired adjustment. The total capacitance of the correction condenser C.sub.S for a horizontal deflection circuit is variable by selectively connecting in parallel therewith correction condensers C.sub.S1 and C.sub.S2 by switches SW.sub.1 and SW.sub.2 during the scanning interval. Therefore, the correction characteristic is improved. Namely, it is possible to obtain a highly accurate S-shaped correction signal. In addition, it is possible to independently control the width of the front portion and rear portion of the horizontal scanning interval by controlling externally inputted direct control current signals DA-C.sub.TL1 and DA-C.sub.TL2.

Abstract: A high voltage generation circuit incorporates the horizontal circuit of a cathode ray tube (CRT) monitor. The horizontal circuit comprises a horizontal output transistor, a retrace capacitor coupled in parallel with the horizontal output transistor, a damping diode which clamps the minimum voltage at the drain of the transistor to approximately ground potential, and a flyback transformer. The primary winding of the flyback transformer is coupled between a terminal where a DC power supply B+ is applied and the drain of the horizontal output transistor. A second transformer is provided between the retrace capacitor and the ground for producing a voltage at the secondary winding thereof each time a free oscillation occurs between the damping interval Td of the damper diode and the conduction interval Ton of the horizontal output transistor.

Abstract: A display device having a set protecting function upon generation of an abnormal voltage includes a horizontal deflection circuit for providing a horizontal signal to a deflection yoke connector, a high voltage output circuit for supplying a high voltage to an anode in accordance with an oscillating signal applied from the horizontal deflection circuit, a power supply circuit for supplying power to the horizontal deflection circuit, and an abnormal voltage detector disposed between the deflection yoke connector, and the high voltage output circuit and the power supply circuit, for detecting whether the deflection yoke connector is connected and whether a part of the high voltage output circuit is damaged, to thereby control a power output of the power supply circuit in accordance with a detected result.

Abstract: In a vertical sawtooth generator of a vertical deflection circuit, a first comparator generates an output signal when a retrace portion of a sawtooth signal is at a first magnitude to initiate a vertical trace portion of the sawtooth signal. An amplifier responsive to the sawtooth signal and to a reference signal generates a feedback current at a time that occurs between the center of vertical trace and the end of trace and away from the center of trace. The feedback current is determined in accordance with a difference between the sawtooth signal and the reference signal. The feedback current is coupled to a first capacitor to develop a gain control voltage. The control voltage is applied via a voltage-to-current converter to an integrating capacitor to develop in the integrating capacitor the trace portion of the sawtooth signal. The control voltage is initialized during a power start-up interval.

Abstract: A voltage control circuit to control a focus exactly by controlling a front/back porch voltage level of a vertical focus control signal regardless of a slight error in an upper and a lower part of a cathode-ray tube. In order to control the front/back porch level of the vertical focus control signal, a certain level of a DC voltage put out by a level controller is added to a saw tooth wave generated by integrating a DC voltage put out by a microcomputer in a first integrator. In a second integrator, a parabola wave is generated by secondly integrating the DC voltage. The level of the DC voltage added to the saw tooth wave is controlled by putting out the generated parabola wave as the vertical focus control signal according to a slight error generated in the upper and the lower part of a cathode-ray tube, and this enables to control the front/back porch voltage level of the vertical focus control signal and the focus exactly in the upper and the lower part of the screen.

Abstract: The present invention relates to a multi-frequency display system and method for providing color convergence. The system comprises a convergence circuit that is configured to receive a first set and a second set of color input signals. The first of color input signals operates at a first frequency, and the second set of color input signals operates at a second frequency. The system also comprises a controller circuit coupled to the convergence circuit, that is configured to generate a first convergence signal corresponding to the first frequency and a second convergence signal corresponding to the second frequency. The convergence circuit generates a first control signal in response to the first set of color input signals and the first convergence signal. The convergence circuit generates a second control signal based on the second set of color input signals and the second convergence signal.