JP2005191848A - Cathode-ray tube display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cathode-ray tube display, having a demagnetization coil and a geomagnetism correcting coil, in which demagnetization effect and geomagnetism correction effect are obtained, while reducing the power consumption. <P>SOLUTION: A demagnetization coil and a geomagnetism correction coil provided in a cathode ray tube display are connected, respectively, to a demagnetization circuit and to a geomagnetism correction circuit and regulation amount of the polarity and level of a DC current flowing through the geomagnetism correction coil is controlled, in response to user operation. Data of the regulation amount determined by user operation is stored in a memory; and next when power is turned on, a demagnetization current is fed to the demagnetization coil based on control at a control section (microcomputer); a geomagnetism correction current, based on the regulation amount data stored in the memory, is fed to the geomagnetism correction coil and current supply to the demagnetization coil; and the geomagnetism correction coil is stopped upon the elapsing of a predetermined time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a display device using a cathode ray tube, and more particularly to a cathode ray tube having a degaussing coil and a geomagnetism correction coil and capable of correcting demagnetization of a magnetic field magnetized on a shadow mask and image color unevenness due to geomagnetism. The present invention relates to a display device.

  In an image display device using a cathode ray tube (hereinafter referred to as CRT), for example, a display device such as a color television receiver, the shadow mask in the CRT is magnetized by the influence of an external magnetic field, and the trajectory of the electron beam fluctuates. However, color purity may deteriorate or raster distortion may occur. For this reason, in general, a degaussing coil is attached to the outer periphery of the CRT, and demagnetization is performed by flowing an alternating attenuation current through the degaussing coil.

  Further, in a display device using such a CRT, the influence of extraneous magnetism such as geomagnetism is increased, and the display image may be rotated or uneven in color depending on the installation location and installation direction. For this reason, a geomagnetic correction coil is attached to the outer periphery of the neck side of the CRT so as to remove the influence of an external magnetic field caused by geomagnetism or the like.

For example, in the CRT display device described in Patent Document 1, a degaussing coil and a rotation correction coil are attached to the outer periphery of the CRT, and when a display image rotates, a direct current is passed through the rotation correction coil to make the display screen horizontal and vertical. An example of maintaining the state is described. In this case, the DC current amount is determined by the user's operation, and after the user operation, information related to the DC current amount is stored in the storage device. When the power is turned off and the power is turned on again, the information stored in the storage device is stored. Therefore, the influence of geomagnetism is reduced by continuously supplying a predetermined direct current to the rotation correction coil.
Japanese Patent Laid-Open No. 9-247698 (pages 3 to 4, FIG. 1)

  The cathode ray tube display device configured to include the demagnetizing coil and the rotation correction coil as described above has a drawback in that power consumption increases because it is necessary to always pass a predetermined direct current through the rotation correction coil.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image display device that obtains a demagnetizing effect and a geomagnetic correction effect while reducing power consumption.

  The present invention has been made to solve such problems. In a display device having a cathode ray tube, the degaussing coil and the geomagnetism correction coil respectively provided on the outer periphery of the cathode ray tube, and the degaussing coil are degaussed. Demagnetization circuit for supplying current, geomagnetism correction circuit for supplying geomagnetism correction current to the geomagnetism correction coil, and adjustment amount relating to polarity and level of geomagnetism correction current flowing in the geomagnetism correction coil in response to a user operation , A memory capable of storing the adjustment amount data determined by the user operation, and supplying a demagnetizing current to the demagnetizing coil when the display device is turned on, and the memory to the geomagnetic correction coil The geomagnetism correction current is supplied based on the adjustment amount data stored in, and the degaussing coil and the geomagnetism correction after a predetermined time elapses. Characterized by comprising a control unit to stop the current supplied to yl.

  Since the cathode ray tube display device of the present invention determines the amount of current flowing through the geomagnetism correction coil and the polarity based on the adjustment amount stored in the memory, the geomagnetism correction can be performed quickly when the power is turned on, and By limiting the interval, power consumption can be reduced.

  Hereinafter, a cathode ray tube display device according to the present invention will be described in detail with reference to the drawings.

  Examples of the present invention will be described below. FIG. 1 is a block diagram showing the overall configuration of a cathode ray tube display device of the present invention, FIG. 2 is a circuit diagram showing the configuration of the main part of the present invention, and FIG. FIG. 4 and FIG. 5 are waveform diagrams showing demagnetizing current and geomagnetic correction current waveforms according to the present invention.

  In FIG. 1, reference numeral 1 denotes a color television receiver. The color television receiver 1 includes a receiving unit (tuner) 3 that receives a signal from an antenna 2, and the receiving unit 3 includes a signal processing circuit 4. It is connected to the. The receiving unit 3 and the signal processing circuit 4 are controlled by a microcomputer 5 (hereinafter referred to as the microcomputer 5), and the receiving unit 3 selects a signal of a desired channel and supplies the signal to the signal processing circuit 4 for this signal processing. The circuit 4 outputs a video signal (RGB signal) adjusted in brightness, contrast, etc. based on various control data from the microcomputer 5 and supplies it to the cathode of a color cathode ray tube 6 (hereinafter referred to as CRT 6). Yes.

  Further, horizontal and vertical synchronizing signals are separated from the signal processing circuit 4 and supplied to the deflection circuit 7. In the deflection circuit 7, a vertical deflection current is generated based on the vertical synchronization signal, and a horizontal deflection current is generated based on the horizontal synchronization signal and output to the deflection yoke 8. The deflection yoke 8 deflects the electron beam of the CRT 6 based on the vertical deflection current and the horizontal deflection current.

  On the other hand, a geomagnetic correction coil 9 is attached to the outer periphery of the neck of the CRT 6 close to the deflection yoke 8 in order to correct the color unevenness of the image due to geomagnetism. Further, a degaussing coil 10 is attached to the outer periphery of the CRT 6 near the shadow mask. The geomagnetism correction coil 9 and the demagnetization coil 10 are supplied with the geomagnetism correction current and the demagnetization current from the correction circuit 11. Details of the correction circuit 11 will be described with reference to FIG.

  The microcomputer 5 includes a ROM, a RAM, and the like, and a nonvolatile memory 12 is connected thereto. The microcomputer 5 controls the television receiver 1 in response to various command signals from a remote controller 13 (hereinafter referred to as a remote controller 13) as operation means.

  The remote controller 13 includes a menu key 131 and an enter key 132 in addition to a power on / off key and a numeric keypad, and further includes an adjustment key 133 and the like. The menu key 131 is operated, for example, when displaying a video or audio adjustment menu screen, and the adjustment key 133 is used to correct a menu item selection or adjustment amount. is there. An enter key 132 is for determining menu items and correction values.

Next, the configuration of the main part of the present invention will be described with reference to FIG. FIG. 2 shows details of the correction circuit 11 in FIG. In FIG. 2, 21 indicates an AC outlet (AC power supply), and switches SW1 and SW2 indicate a main power switch and a sub power switch provided in the television receiver main body, respectively. A degaussing circuit 23 including a degaussing coil 10, a positive temperature coefficient thermistor 22, and a switch SW3 is connected between the AC lines at the subsequent stage of the sub power switch SW2.

  When an AC voltage is supplied to the degaussing coil 10, an AC magnetic field is generated, and the switch SW3 is controlled by the microcomputer 5 to perform on / off control of the degaussing circuit 23. When the degaussing circuit 23 is on, the positive temperature coefficient thermistor 22 increases in resistance due to temperature rise due to self-heating, and attenuates the degaussing current flowing through the degaussing circuit 24 over time.

The main power supply circuit 24 provided in the subsequent stage of the sub power switch SW2 rectifies and smoothes the AC voltage to output a predetermined DC voltage, and supplies an operating voltage to each part of the television receiver.
On the other hand, a standby power supply circuit 25 is provided in the AC line following the switch main power switch SW1 so as to supply an operating voltage to the microcomputer 5 or the like when the television receiver is in a standby state.

  In addition, a polarity inversion circuit 26 and a correction amount adjustment circuit 27 are connected to the geomagnetism correction coil 9 to form a geomagnetism correction circuit 28. The correction amount adjusting circuit 27 outputs a predetermined DC current to the geomagnetic correction coil 9 provided at the neck portion of the CRT 6 based on a control signal from the microcomputer 5 and stops supplying the DC current after a predetermined time has elapsed. Like that. Further, the polarity inversion circuit 26 is controlled based on the control signal from the microcomputer 5 to control the direction of the current flowing in the geomagnetic correction coil 9.

  Next, the operation of the correction circuit 11 shown in FIG. 2 will be described with reference to FIGS. First, the case where the main power switch SW1 is turned on at the time of installation of the television receiver (at the time of initial setting) will be described. When the sub power switch SW2 is turned on in this state, the operating voltage is supplied from the main power circuit 24, and the control signal from the microcomputer 5 controls the SW3 to be turned on for a predetermined time. As a result, an AC voltage is supplied to the degaussing circuit 23, and an AC current I as shown in FIG. 4 is supplied to the degaussing coil 10 to generate an AC magnetic field. At this time, since the alternating current I also flows through the positive temperature coefficient thermistor 22, the temperature of the positive temperature coefficient thermistor 22 rises due to self-heating and the resistance value increases. As a result, the alternating current I flowing through the degaussing coil 10 is limited as time passes and finally hardly flows, and the alternating magnetic field generated in the degaussing coil 10 is attenuated accordingly. Then, the magnetism demagnetized on the shadow mask or the like is demagnetized to complete the demagnetization operation, and the switch SW3 is turned off after the predetermined time t1 has elapsed.

  On the other hand, when the image displayed on the display screen is uneven due to the influence of geomagnetism or the like, the user adjusts the beam to move clockwise as shown in FIG. 3A while viewing the state of the displayed image. On the contrary, the remote controller 13 is operated so as to move and adjust counterclockwise as shown in FIG. In response to the operation of the remote controller 13, the magnitude and polarity of the direct current supplied to the geomagnetic correction coil 9 are adjusted, and data relating to the adjustment level is stored in the memory 12.

  That is, when the menu button 131 of the remote controller 13 is operated, a screen for correcting geomagnetism is displayed on the screen, and when one of the cursor keys 133 is operated, for example, the direction indicated by the arrow a1 in FIG. Move the beam to adjust color unevenness. Conversely, by operating another one of the cursor keys 133, the beam is moved in the direction indicated by the arrow b1 in FIG. When the adjustment amount becomes an appropriate value, the data of the adjustment amount (data regarding the polarity and level of the geomagnetic correction current) is stored in the memory 12 by pressing the enter key 132.

In this way, as shown in FIG. 4, the correction circuit 11 changes the level and polarity of the direct current supplied to the geomagnetism correction coil 9 in response to the operation of the remote controller 13, and thereafter the direct current based on the set adjustment amount data. A level and polarity current Idc is supplied to the geomagnetic correction coil 9 so as to eliminate color unevenness of the image.

  Next, the geomagnetic correction operation when the sub power switch SW2 is turned off and then the sub power switch SW2 is turned on again will be described with reference to FIG. In this case, the microcomputer 5 turns on the switch SW3 and causes the degaussing current I to flow through the degaussing coil 10. Further, the microcomputer 5 controls the geomagnetic correction current Idc to flow through the geomagnetic correction coil 9 based on the adjustment amount data stored in the memory 12.

  Further, the microcomputer 5 turns off the switch SW3 after a predetermined time t1 after the power switch Sw2 is turned on (AC on), stops the demagnetizing current I, and supplies the geomagnetic correction current Idc after the predetermined time t2. The correction amount adjustment circuit 27 is controlled so as to stop. That is, at the initial setting, the geomagnetic correction current Idc is controlled in amount and polarity according to the user's operation as shown in FIG. 4, and the data of the amount of adjustment is stored, and then the AC power is turned off and turned on again. If the demagnetizing current I is generated, the geomagnetic correction current Idc is controlled to flow simultaneously with the generation of the demagnetizing current I based on the stored adjustment amount data. Further, the geomagnetic correction current Idc is turned off after a predetermined time t2. After the time t2, the inner shield (not shown) provided in the CRT 6 is magnetized by the geomagnetic correction current Idc, so that the geomagnetic correction is continued.

  In addition, when the time passes or the installation position of the television receiver is changed, the geomagnetic correction amount is controlled again by the user, and the geomagnetic correction amount is adjusted by operating the remote controller 13 as shown in FIG. Thus, the microcomputer 5 stores the new adjustment amount data in the memory 12.

  In this way, when the display image is rotated or fluctuated due to the influence of geomagnetism, etc., the user adjusts the image so that the rotation or fluctuation of the image is minimized while observing the state of the displayed image. By storing in the memory 12, the next time the AC power is turned on, the operation state described with reference to FIG. 5 is entered.

  Therefore, it is only necessary to pass the direct current Idc through the geomagnetic correction coil 9 for a predetermined time, and the power consumption can be reduced.

1 is a block diagram showing the overall configuration of a cathode ray tube display device of the present invention. (Example 1) The circuit diagram which shows the structure of the principal part of the cathode ray tube display apparatus of this invention. Explanatory drawing of the display screen which shows the operation | movement of the geomagnetic correction in this invention. The wave form diagram which shows the waveform of the demagnetizing current at the time of initialization, and a geomagnetic correction electric current. The wave form diagram which shows the waveform of the demagnetizing current at the time of normal operation, and a geomagnetic correction current.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Television receiver 2 Antenna 3 Receiving part 4 Signal processing circuit 5 Microcomputer 6 Cathode ray tube (CRT)
DESCRIPTION OF SYMBOLS 7 Deflection circuit 8 Deflection yoke 9 Geomagnetic correction coil 10 Demagnetization coil 11 Correction circuit 12 Memory 13 Remote control 21 AC outlet 22 Positive characteristic thermistor 23 Demagnetization circuit 24 Main power supply circuit 25 Standby power supply circuit 26 Polarity inversion circuit 27 Correction amount adjustment circuit 28 Geomagnetic correction circuit

Claims (5)

In a display device having a cathode ray tube,
A degaussing coil and a geomagnetism correction coil respectively provided on the outer periphery of the cathode ray tube;
A degaussing circuit for supplying a degaussing current to the degaussing coil;
A geomagnetism correction circuit for supplying a geomagnetism correction current to the geomagnetism correction coil;
Means for controlling an adjustment amount relating to a polarity and a level of a geomagnetic correction current flowing through the geomagnetic correction coil in response to a user operation;
A memory capable of storing data of the adjustment amount determined by the user operation;
When the display device is turned on, a demagnetizing current is supplied to the demagnetizing coil and a geomagnetic correction current based on the adjustment amount data stored in the memory is supplied to the geomagnetic correction coil. A cathode ray tube display device comprising: a control unit that stops current supplied to the coil. 2. The cathode ray tube display device according to claim 1, wherein the control unit is a microcomputer, and the means for controlling the adjustment amount in response to the user operation is a remote controller. 2. The cathode ray tube according to claim 1, wherein the geomagnetism correction circuit comprises an adjustment circuit for adjusting a DC current amount flowing through the geomagnetism correction coil, and a polarity inversion circuit for switching the polarity of the DC current amount flowing through the geomagnetism correction coil. Display device. When the adjustment amount is adjusted by the user operation, a geomagnetism correction current corresponding to the adjustment amount is supplied to the geomagnetism correction coil, and when the AC power is turned off and then turned on again, the demagnetization current is supplied to the demagnetization coil. 2. The cathode ray tube display device according to claim 1, wherein a geomagnetism correction current based on adjustment amount data stored in the memory is caused to flow through the geomagnetism correction coil. 2. The cathode ray tube according to claim 1, wherein the degaussing coil is attached to an outer peripheral portion corresponding to a shadow mask of the cathode ray tube, and the geomagnetic correction coil is attached to an outer peripheral portion corresponding to an inner shield of the cathode ray tube. Display device.

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