Abstract: The invention relates to a method and apparatus for correcting image errors caused by residual magnetism in monitors and other such display devices based on picture tubes. The method according to the invention is based on the removal of residual magnetism by means of an alternating damped magnetic field. In the method, the internal and external structures in the neck part (11) of a picture tube (10) are subjected to an alternating damped magnetic field produced by means of a coil (45).

Abstract: A method of calculating beam landing errors in an electronic display device having color phosphor elements and electron guns to generate electron beams to impinge on corresponding phosphor elements require a magnetic field to be generated to deflect an electron beam relative to the corresponding phosphor element on which the electron beam is to impinge. The intensity of light emitted by the phosphor elements in the measurement area is measured as the electron beam impinges thereon. The polarity of the magnetic field is reversed and the above step is repeated. Thereafter, the magnitude of the magnetic field is changed and the above two steps are repeated thereby to measure at least two different light intensities resulting from electron beam influenced by each polarity magnetic field. The at least two different light intensities resulting from electron beams influenced by each polarity magnetic field are then approximated with straight lines and an intersection point of the straight lines is determined.

Abstract: An apparatus for electron beam deflection in a cathode ray tube, in particular in a picture tube of a television set, comprises a deflection coil arrangement for horizontal and vertical deflection of the electron beam, an auxiliary deflection coil arrangement, by means of which the electron beam can be influenced for the purpose of convergence correction, and a compensation coil arrangement for producing a magnetic compensation field. The compensation coil arrangement is arranged and designed such that the compensation field essentially compensates for the stray magnetic field of the deflection coil arrangement in the physical region of the auxiliary deflection coil arrangement.

Abstract: A cathode-ray tube video device connected to a power source and having a first normal operating state and at least a second operating state at reduced power (stand-by mode) includes a switching power supply and a circuit portion for demagnetizing the cathode-ray tube coupled to the power source through an electrically actuated switch. The switch is closed to demagnetize the cathode-ray tube during the first operating state of the device, and opened during the second operating state at reduced power of the device.

Abstract: An anode ripple voltage waveform is detected by a capacitor built into a flyback transformer. The detected waveform is then phased by a phasing circuit, amplitude adjusted by an amplitude adjusting circuit and subsequently delivered to an addition circuit. A horizontal component is detected by a horizontal output transformer, then phase adjusted by a phasing circuit and subsequently amplitude adjusted by an amplitude adjusting circuit. Thereafter, the horizontal component is added to the anode ripple component by the addition circuit, inverted and amplified by an inverting amplifier, and then supplied to an antenna arranged in proximity to the cathode ray tube. Thus, electric fields radiated from the face of the cathode ray tube are suppressed.

Abstract: A degaussing circuit is formed as a series connection of a PTC element and a degaussing coil operated such that the operating frequency of the current therethrough is higher than the frequency of the power source line for the device such as a color television set in which this degaussing circuit is incorporated. This frequency conversion may be effected by a circuit which also functions to convert the alternating current from the power source line into a direct current. The degaussing circuit may further include a relay circuit for switching on and off the current through the PTC element and the degaussing coil.

Abstract: An external magnetic field correction device capable of preventing malfunctions of the external magnetic field correction device due to operation of a degaussing circuit by judging that an abnormality has occurred when an output of an external magnetic field detector is not less than a predetermined value and interrupting offset adjustment process accordingly, and that is capable of limiting irregularities of offset current in operational current of the magnetic field correction device to predetermined value or less by adjusting an offset value as to make correction current to be supplied to an external magnetic field correction coil when an external magnetic field around a CRT is zero to a regular value or less.

Abstract: A degaussing coil is driven when a driving request for the degaussing coil is received after turning on of a main power supply of a cathode ray tube and a driving request for the degaussing coil is set when the driving time of the degaussing coil is less than a reference time in case that the main power supply is turned off within the predetermined reference time. Consequently, the degaussing coil is driven regardless the time from turning off to turning on of the main power supply. Accordingly, the method for controlling the degaussing coil of the cathode ray tube can prevent the remanence of the cathode ray tube and always provide a safe image to a user.

Abstract: The present invention relates to a circuit for eliminating radiated electric field noise in a video appliance which can completely offset radiated electric field noise generated on the front face of the CRT by variably adjusting and applying the waveform signal, the amplitude and phase of which are opposite to those of the radiated electric field noise formed on the front face of the CRT. The circuit for eliminating radiated electric field noise according to the present invention includes a high voltage ripple offset section including a cylindrical core, wherein a high voltage lead wire of the FBT passes through the cylindrical core, for eliminating a ripple component of the high voltage applied to the anode of the CRT according to the negative polarity pulse signal from the FBT induction coil, and an electric field noise offset section operable to offset the radiated electric field noise generated from the front face of the CRT by applying the negative polarity pulse signal to the periphery of the CRT.

Abstract: A video display appliance having a device for eliminating the radiation wave emitted from a cathode ray tube. The appliance includes a shielding wire wound one to several times along the periphery of a degaussing coil. The pulses having the same level and phase, but inverse polarity to those applied to an anode of the cathode ray tube, is applied to the shielding wire, thereby offsetting the radiation wave emitted from the cathode ray tube.

Abstract: An anode ripple voltage waveform is detected by a capacitor built into a flyback transformer. The detected waveform is then phased by a phasing circuit, amplitude adjusted by an amplitude adjusting circuit and subsequently delivered to an addition circuit. A horizontal component is detected by a horizontal output transformer, then phase adjusted by a phasing circuit and subsequently amplitude adjusted by an amplitude adjusting circuit. Thereafter, the horizontal component is added to the anode ripple component by the addition circuit, inverted and amplified by an inverting amplifier, and then supplied to an antenna arranged in proximity to the cathode ray tube. Thus, electric fields radiated from the face of the cathode ray tube are suppressed.

Abstract: An automatic degaussing circuit for a color picture tube (CPT) capable of automatically degaussing the CPT when a power conservation mode is released in a monitor having a power conservation function. The degaussing circuit includes a degaussing coil for eliminating electromagnetic waves produced from the CPT, a power conservation mode detecting section for detecting the release of the power conservation mode in accordance with a power conservation mode signal of the CPT inputted thereto and providing a degaussing control signal for controlling the operation of the degaussing coil if the release of the power conservation mode is detected, and a degaussing coil driving section for driving the degaussing coil for a predetermined time in accordance with the degaussing control signal when the power conservation mode is released.

Abstract: A degaussing circuit is adapted to overcome a problem with limitations in the design of a printed circuit board under the safety regulations. The degaussing circuit is realized by making use of the horizontal deflection wave generated by a horizontal deflection circuit, and includes: a degaussing control section for detecting a horizontal frequency from the horizontal deflection wave received from the horizontal deflection circuit; and a degaussing coil for eliminating the earth magnetic field caused by a DC component from the horizontal frequency received from the degaussing control section.

Abstract: Circuitry to control a power supply of a degaussing coil of a cathode ray tube, said degaussing coil is coupled to a main voltage supply through a switching device the circuitry has inputs coupled to a direct source of current of a switched mode power supply, the switched mode power supply comprises a switched mode transformer with primary windings coupled to the main source of voltage, and secondary windings and the switched mode power supply is switched in a first range of frequencies when the power supply is in a "standby" mode and in a second range of frequencies when the power supply is in an "on" mode wherein said circuitry comprising a detecting circuit which detectes a change in the range of switching frequencies when the power supply is switched from standby to on, the detecting circuit having an input coupled to a direct current source being downstream of a primary winding of the switched mode transformer and an output coupled to an input of a control circuit of the switching device the control circ

Abstract: A picture tilt complementing circuit in a display device includes: a microcomputer for receiving horizontal and vertical sync signals from a computer and generating a tilt control signal; a horizontal sawtooth wave generation unit for converting the tilt control signal transmitted from the microcomputer into a sawtooth wave signal according to a horizontal fly back signal; a vertical sawtooth wave generation unit for converting the tilt control signal transmitted from the microcomputer into a sawtooth wave signal according to a vertical fly back signal; a vertical center control unit for synthesizing a horizontal sawtooth wave signal generated by the horizontal sawtooth wave generation unit with a vertical position control signal transmitted from the microcomputer and sending the synthesized result to a vertical output unit; and a horizontal position control unit for synthesizing a vertical sawtooth wave signal generated by the vertical sawtooth wave generation unit with a horizontal position control signal t

Abstract: A degaussing circuit includes an AC mains voltage, a series arrangement of a degaussing coil (Ld) and a switching element (S1) coupled between the input terminals (it1,it2). A measuring circuit (3) continuously measures a value (Ms) representing an actual value of either the degaussing current (Id) through the degaussing coil (Ld) or the AC mains voltage (Vac). A detecting circuit (2) detects a level crossing instant (ts) at which the actual value (Ms) crosses a predetermined value (Vref2). A control circuit (1) determines a switching instant (tei,tstv) of the switching element (S1) in response to the level crossing instant (ts) for generating a peak value of the degaussing current (Id) related to the actual value of the degaussing current (Id) or the AC mains voltage (Vac) at the level crossing instant (ts).

Abstract: A display apparatus including a CRT having a deflection yoke, a plurality of field radiation restriction electrodes and a field radiation restriction circuit including an amplitude adjuster for applying, to at least one of the field radiation restriction electrodes, pulse voltage having polarity in reverse to the polarity of pulse voltage to be applied to the deflection yoke and a differential waveform adjuster for applying, to at least another field radiation restriction electrode, pulse voltage obtained by differentiating the pulse voltage to be applied to the deflection yoke.

Abstract: A leakage flux canceling device is provided which requires a small number of parts and which has high space factor. A leakage flux canceling device 30 is mounted to a funnel side of a deflecting apparatus for reducing leakage flux to a panel side attributable to a horizontal deflection magnetic field, and comprises a ring-like body 32 having flanges 32 facing each other, a pair of bobbins 40 and 60 without cores formed on the flanges, a canceling coil 34 wound on each of the bobbins for canceling leakage flux, and winding grooves 48 and 68 formed in the respective bobbins such that the winding of each canceling coil has a greater length in the circumferential direction, and permitting the canceling coils to be wound from the outer surface side of the corresponding bobbins. The bobbins and the ring-like body are formed as a one-piece body, and the bobbins each have an arcuate shape matching the ring-like body.

Abstract: An automatic image rotation compensation circuit includes: a terrestrial magnetic field detecting unit for detecting horizontal and vertical terrestrial magnetic fields of a place where a display device is installed; an amplifying unit for amplifying the horizontal and vertical terrestrial magnetic field values detected by the terrestrial magnetic field detecting unit; an analog-to-digital converting unit for converting the analog terrestrial magnetic field values amplified by the amplifying unit into digital signals; a memory for storing image compensation reference values corresponding to various terrestrial magnetic field values; a microcomputer for receiving the digital terrestrial magnetic field values from the analog-to-digital converting unit and reading compensation values corresponding to the terrestrial magnetic field values; a digital-to-analog converting unit for converting the digital signals from the microcomputer into analog signals; and a deflection controller for performing a differential amp

Abstract: A device for shielding an electrical field emitted backward from a video display appliance. The device includes a device for shielding an electrical field emitted backward from a video display appliance including a CRT having an anode to which a high voltage is supplied, a deflection yoke for deflecting electron beams produced from electron guns, and a video board for processing and outputting video signals to the CRT, the device comprising, a first patterned section printed on a periphery of a back of the video board and connected to ground, and a second patterned section printed inside the first patterned section, the scond patterned section having a pulse applying portion to which a pulse voltage having a polarity opposite to the electric field waveform is applied and a termination portion.

Abstract: A transparent conductive film is formed on an outer surface of a face portion of a face panel and a phosphor screen is formed on an inner surface thereof. A conductive explosion proof band is wound around an outer periphery of a skirt portion of the face panel and the explosion proof band has a grounding potential. A conductive tape is attached along a long side of the face panel and electrically connects the transparent conductive film with the explosion proof band. A compensating electrode extending along a side of the face panel is attached to an upper side of the skirt portion and disposed on a side opposite to the conductive tape with respect to the explosion proof band. An inverse voltage applying portion applies a voltage having a waveform of a polarity inverse to that of the deflection voltage applied to a deflection device to the compensating electrode so as to generate an electric field for canceling an alternating electric field generated from the deflection device.

Abstract: A holder for supporting a degaussing coil on a cathode ray tube. The degaussing coil holder is a flexible sheet having holes formed in each end to receive a lug of the cathode ray tube.

Abstract: A tilt compensation circuit for a picture tube is provided to correct an image rotation phenomenon of a currently displayed image on a screen caused by an outer interference such as terrestrial magnetism. In the picture tube, an alternating current for driving the tube is applied to a power supply circuit for voltage conversion through an AC line filter and to a degaussing coil as well. The circuit includes a tilt adjustment circuit for comparing a tilt compensation control signal of a predetermined voltage level with a voltage feedback signal from the degaussing coil thereby generating current corresponding the difference therebetween. The circuit further includes a switching circuit responsive to a state of the tilt compensation control signal for selectively switching between a first circuit loop incorporating the AC line filter and the degaussing coil and a second loop incorporating the tilt adjustment circuit and the degaussing coil.

Abstract: A device for removing electric field of a display according to the present invention comprises: a voltage generator connected to a horizontal deflection output circuit of a CRT and generating an antiphase reverse pulse having a frequency band equal to that of a horizontal output pulse; a reverse pulse sensor made of a conductive material, insulated at a given location in the front part of the CRT, and generating the reverse pulse around the CRT; and a connector for detecting the reverse pulse of the voltage generator, connected to ground at one end thereof and the reverse pulse sensor at the other end thereof, and sending the reverse pulse to the reverse pulse sensor.

Abstract: The invention provides a device for effectively decreasing the electric field irradiated from the front surface of a CRT display. This device cancels the leakage field composed of a deflection component and a high voltage ripple component irradiated in the front direction of the CRT by generating an inverse electric field composed of the deflection component and high voltage ripple component. The inverse electric field is obtained by detecting an alternating-current voltage irradiated in the anode portion of the CRT by capacitive coupling a detector to the anode, inverting and amplifying the detected voltage, and applying the inverted voltage to an inverse field generating means installed near the front surface of the CRT.

Abstract: A video display appliance comprising a cathode ray tube 2 having a deflection yoke 22 mounted thereto, a cabinet 4, and a back cover 6, the cabinet and the back cover being connected to house the CRT. The video display appliance also comprises a magnetic field absorbing coil 30 placed between a glass envelope 12 and the deflection yoke 22, a magnetic field remover 25, a back plate 34 mounted on a video board 27, a below plate 28, and a shielding member 60, 160 or 260 secured detachable to the inner surface of the back cover 6, for shielding the electromagnetic field emitted from the deflection yoke. The shielding means comprises an oblong closed-loop wire 62, 162, 262 or 265, and lead wires 64 having at each end a ground terminal. Accordingly, the electric field emitted in an upward direction from the deflection yoke is easily eliminated by means of the shielding member having a simple construction and being easily installed.

Abstract: An electromagnetic field shielding circuit is disclosed. The circuit comprises a phrase inverting circuit, coupled to a turn in the secondary windings, for generating an inverted phase with respect to a phase of a voltage signal induced to the anode electrode from the secondary windings. An oscillation circuit oscillates a voltage signal output from an output node of the phase inverting circuit. The oscillating circuit matches an oscillating signal with a high voltage level signal. An electromagnetic field generation circuit applies a voltage signal output from an output mode of the oscillation circuit. This generates an electromagnetic field responsive to the voltage signal substantially around the circumferential periphery of the front portion of the picture tube. This electromagentic field cancels and shields the electromagnetic field generated from the anode.

Abstract: A color cathode-ray tube is demagnetized or magnetized in a magnetic transfer process with a direct-current biasing magnetic field, using an alternating-current magnetic field which is attenuated to a median thereof in a median attenuating time of at least 0.1 second.

Abstract: A method of degaussing a cathode ray tube where two pairs of degaussing coils are arranged with one pair located at the top and bottom and the other to the right and left of the cathode ray tube after impaired color purity correction process of an electron beam has been carried out for the cathode ray tube using a magnetization process with a magnetization including an anticipated amount of degaussing for the cathode ray tube when the cathode ray tube is incorporated in a display device. The degaussing of a magnetic material within the cathode ray tube is then carried out with the anticipated amount of degaussing using the degaussing coils. In this way, a color cathode ray tub with no impaired color purity can be provided because the cathode ray trajectories corrected by magnetization in the magnetization process is not easily changed during use after incorporation in the display device.

Abstract: A magnetic compensating circuit includes a magnetic sensor (1), a control circuit (2) for generating a signal for magnetic compensation, and coils (3) for magnetic compensation. The magnetic sensor has a pair of amorphous magnetic substance wires (101) arranged in parallel, coils (102) for providing the pair of amorphous magnetic substance wires with bias magnetic fields in directions opposite to each other, a high-frequency power source (105) for supplying the pair of amorphous magnetic substance wires with high-frequency currents, and circuits (106, 107, 108, 109) for outputting a potential difference derived from the output of the pair of amorphous magnetic substance wires. Thus, this magnetic compensating circuit is capable of detecting a minute external magnetic field with high accuracy.

Abstract: The present invention is situated in the presence of an image source having an image and a display device having an image alignment register, a pixel address, and a pixel signal, the display device coupled to the image source. The apparatus of the present invention preferably comprises a pixel level comparator, a computer, and a pixel detection unit. The pixel level comparator is for setting a pixel detect signal to true if the pixel signal exceeds a threshold. The pixel level comparitor is coupled to the display device. The computer has a selected address and is coupled to the image alignment register. The pixel detection unit is for setting a pixel data signal to true if, while the pixel address and the selected address are equivalent, the pixel detect signal is set to true. The pixel detection unit is coupled to the display device, the pixel level comparitor and the computer.

Abstract: An improved degaussing circuit for a television set capable of preventing color blurring phenomenon and picture quality deterioration by degaussing television set of which its picture quality is affected by an external magnetic field at the time of turning on and turning off the television set, which includes an LC oscillating circuit for receiving a first direct current voltage and for flowing a degaussing current; a switching unit sequentially turned on in accordance with a turning on/off operation of a television set for enabling an oscillating operation of the LC oscillating circuit; a first trigger circuit for receiving a second direct current voltage and for enabling the LC oscillating circuit by turning on the switching unit after a certain time is lapsed after the television set is turned on; a second trigger circuit for receiving a second direct current voltage for turning off the switching unit when the LC oscillating circuit completes the degaussing operation in accordance with a control of the fir

Abstract: Apparatus for mitigating the adverse effects of magnetic interference on the operation of a CRT is provided. More specifically, magnetic sensors are placed in a gap formed between a front bezel and a rear enclosure comprising a magnetic shield enclosing all but the viewing surface of a CRT. The gap serves to concentrate the on-axis magnetic field and the resultant signal from the sensors is amplified to drive current through a compensation coil located inside the front bezel and in front of the viewing surface of the CRT. The current generates a compensation field that mitigates the incoming on-axis magnetic field. The ambient magnetic field is also sensed by a three axis magnetic sensing assemblage located outside the magnetic shield. The output of the sensing arrangement is operated on to produce a trigger to start a degauss cycle.

Abstract: A system for degaussing a cathode ray tube (CRT) which avoids displaying a distorted picture to the user when a magnetic field is degaussed while the CRT is on. The system of the present invention recognizes when a user has pressed a button to initiate the manual degaussing operation, controls the brightness and contrast of the CRT so that the displayed picture becomes black, degausses the CRT while the picture appears black, and controls the brightness and contrast of the CRT to levels present before degaussing.

Abstract: A bus controlled pulse modulator receives a digitally coded signal and generates a pulse-width modulated signal. The pulse-width modulated signal is coupled to a base electrode of a non-committed or open collector transistor. The transistor switches with a controlled duty cycle. The collector of the transistor is coupled to an inverting input terminal of an amplifier via a resistor. The amplifier produces a compensation current in a tilt compensation coil. The voltage at the inverting input terminal is maintained constant in closed loop operation. The constant voltage produces a magnitude of a collector current in the transistor that is unaffected by the duty cycle of the pulse-width modulated signal. The compensation current thereby varies linearly with the duty cycle.

Abstract: A demagnetizing device for a cathode ray tube having a screen portion and a funnel portion, comprising:an outer magnetic shielding member which is arranged so as to surround a funnel portion of a cathode ray tube, and which is formed of a magnetic sheet; anda demagnetizing coil which is arranged so as to encircle a screen portion of the cathode ray tube;wherein the demagnetizing coil is arranged so as to be apart from the outer magnetic shielding member by not less than 9.5 mm.

Abstract: A display comprising a cathode ray display tube (1) having an electromagnetic deflection yoke (2) is described. A pair of first deflection coils (7,6) are located symmetrically about the longitudinal axis of the tube (1) on opposite sides of the yoke (2) for producing within the tube (1) a first magnetic deflection field. A pair of second deflection coils (8,20) are similarly located symmetrically about the longitudinal axis on opposite sides of the yoke (2) for producing within the lube (1) a second magnetic deflection field at right angles to the first deflection field. The display is further provided with a pair of first cancellation coils (4,3) connected to the first deflection coils (7,6) for producing a first cancellation field which tends to cancel a first stray field produced by the first deflection coils (7,6). Support means (10,11) secure the first cancellation coils symmetrically about the longitudinal axis.

Abstract: A cathode ray tube may utilize a focus mask color-selection structure. The focus mask structure is susceptible to localized, transient short circuit events, or breakdown events. These events may be caused by conductive particulates that become free within the cathode ray tube and provide a short circuit between first and second layers of the focus mask. The breakdown events are undesirable because they may result in cross-strand currents causing mask strand magnetization that can interfere with a video image on the screen of the cathode ray tube. A rapid degaussing operation is initiated during the next subsequent vertical blanking period following detection of the breakdown event.

Abstract: A cathode ray tube display having reduced electric field emissions comprising a cathode ray tube 100, an element 200 for detecting modulations in the final anode voltage of the CRT, the signal not being directly dependent on the deflection driving means 115. A matching network 205 provides phase and gain correction to the signal from element 200, amplification means 210 receives the signal from network 205 and an emission means 215 radiates a cancelling electric field dependent on the modulations detected by said element 200.

Abstract: A color display device comprising a cathode ray tube and a deflection unit also includes a compensation coil or a compensation-coil system, for example, on the outside of the yoke of the deflection unit, so as to compensate for frame errors and convergence errors caused by the earth's magnetic field.

Abstract: A cathode-ray tube apparatus capable of reducing a high frequency electric field radiated from the deflection yoke and the deflection and high voltage circuit to the outside of the cathode-ray tube apparatus. Mounted on the deflection yoke or on the cathode-ray tube are an induction coil for generating a pulse voltage opposite in polarity to a high pulse voltage applied to the h and an electric field cancellation electrode made of a conductive wire to which the opposite polarity pulse voltage is applied. When the opposite polarity pulse voltage is applied to the electric field cancellation electrode, the electric field cancellation electrode radiates an electric field opposite in polarity to the high frequency electric field radiated from the deflection yoke to the outside of the cathode-ray tube apparatus to reduce the intensity of the high frequency electric field.

Abstract: The strip-type retainer device for fitting a degaussing coil of a cathode ray tube in a display device is provided. The retainer device comprises a first end section, a contact section, a middle section and a second end section. The contact section has a plurality of positioning slots. The middle section has a first passage allowing passage of the first end section. The first passage defines a periphery around the passage. A latch is provided on the periphery of the first passage to cooperate with one of a plurality of positioning slots. A second end section has a second passage allowing passage of the lug. The retainer device is removably attached to the peripheral edge of the cathode ray tube. The first end section passes through the first passage and the degaussing coil contacts with the funnel-shape surface of the cathode ray tube tightly by selecting an appropriate positioning slot to cooperate with the latch.

Abstract: A CPU is designed so as to put a demagnetizing circuit in an operative state in accordance with a result of detecting, among other quantities or events, the number of operations to turn on a power counted by a counter, the lapse of time under a predetermined condition measured by a timer since the pulling-out of an AC plug, the movement of the main body of a display device sensed by a sensor unit, an external magnetic field sensed by a sensor unit or a residual magnetism in a CRT itself sensed by a sensor unit. Instead of carrying out demagnetization each time the power is turned on, demagnetization is performed only under certain conditions when necessary, diminishing the problem of wasteful power consumption. On the top of that, the number of cases in which sound and picture vibration are generated due to a demagnetizing operation carried out right after the turning-on of the power is reduced, resulting in a product easy to handle by the user.

Abstract: A cathode-ray tube display unit provided with a high voltage transformer for supplying high voltage to an anode of a cathode-ray tube, a deflection yoke having a horizontal deflection coil and a vertical deflection coil, and an interior conductive coating formed on the inside of a glass vessel of the cathode-ray tube, in which there is provided an electrode in the conductive coating form formed on an external wall face of a glass vessel at a funnel portion being electrically separated from an exterior graphite coating formed on an external surface of the cathode-ray tube and connected to ground, and a circuit for applying reverse pulse voltage V.sub.1 that satisfies (V.sub.0 .times.C.sub.0)>(V.sub.1 .times.C.sub.1) to the electrode in the conductive coating form is included. Where, it is assumed that flyback pulse voltage supplied to the deflection yoke means is V.sub.0, reverse pulse voltage having a polarity reverse to that of voltage generated in the interior conductive coating is V.sub.

Abstract: An automatic degaussing circuit provides a video display apparatus with a degaussing capability over a wide range of ac mains sources. An ac mains source is coupled to a degaussing coil by a series interconnection of first and second temperature-sensitive resistances. The temperature-sensitive resistances have oppositely-tending temperature coefficients, so that a total dc impedance of the automatic degaussing circuit initially decreases after power is applied to the circuit.

Abstract: A television receiver has a switched mode power supply controller, which may be deflection synchronized, which produces pulses in a power transformer. To power the controller during startup, before the internal power supply has started, a storage capacitor on the power supply input of the controller is coupled through a current limiting resistance to a rectified voltage from the AC mains so as to charge the storage capacitor during first polarity phases of the AC mains. The current limiting resistance includes a positive temperature coefficient (PTC) element which increases its impedance as it heats, to reduce power dissipation after initial connection of the television receiver to AC mains. In addition, a diode is coupled in a current path to the storage capacitor to charge the capacitor to the same polarity during opposite polarity phases of the AC mains.

Abstract: A color cathode ray tube display device comprises a color cathode ray tube including a neck portion (1a), a funnel portion (1b), and a panel portion (1c), a compensating coil (7) which generates a compensating magnetic field for eliminating the influence of an external magnetic field that acts vertically on electron beams which will intersect a display screen of the color cathode ray tube (1), a current supply unit (4,5) for passing a sawtooth current synchronized with the vertical deflection cycle of a video signal into the compensating coil (7) so that the compensating coil generates the compensating magnetic field, and a memory (5b) for storing information about the sawtooth current passing through the compensating coil (7).

Abstract: The present invention is concerned with a method and an arrangement relating to visual display units, preferably a picture tube (1), for reducing to a minimum the electrical alternating fields generated by the display unit in the unit surroundings. The visual display unit is provided with a voltage connected part (5) on which undesirable voltage variations occur. These voltage variations are indicated. A signal which is phase inverted in relation to the indicated voltage variations is generated. The generated phase-inverted signal is fed back to the voltage connected part (5), to compensate for the voltage variations.

Abstract: A cathode ray tube apparatus can accurately, easily and automatically correct influences exerted on both of a beam landing drift and an image distortion drift by terrestrial magnetism applied to a cathode ray tube (CRT). A correction current based on an output of a terrestrial magnetism sensor (45) is supplied to a Z-axis correction coil (41) and an X--X axis correction coil (42). A terrestrial magnetism component (B.sub.H cos.theta.) of Z-axis direction is canceled by a correction magnetic flux generated by the Z-axis correction coil (41), and a terrestrial magnetism component (B.sub.H sin.theta.) of X-axis direction is canceled by the X--X axis correction coil (42), whereby a beam landing drift and a image distortion drift are corrected automatically.

Abstract: A compact color monitor device that utilizes active and passive magnetic shielding to eliminate the visible distortion of color displays due to externally-imposed magnetic fields. The color monitor device can be installed in standard 19-inch EIA rack enclosures used on-board surface vessels and remain operable with no color distortion when the vessel is subjected to .+-.5 Oersted degaussing fields. The color monitor device includes a quick-degaussing circuit for degaussing internal components in approximately 1/60 of a second.