WO2004012443A1

WO2004012443A1 - Cathode ray tube apparatus preventing distortion of image caused by variation of luminance

Info

Publication number: WO2004012443A1
Application number: PCT/JP2003/008636
Authority: WO
Inventors: Yukio Uchida
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2002-07-26
Filing date: 2003-07-08
Publication date: 2004-02-05
Also published as: JP2004064357A

Abstract

Distortion of an image caused by variation in the luminance of pixel is eliminated by delivering the output voltage from an AC component extraction circuit (13) for extracting the variation quantity of anode current to a horizontal size control circuit for controlling the strength of horizontal deflection field using a transistor Tr 20, a capacitor C20 and resistors R20-R23, thereby regulating a horizontal deflection current being outputted from a horizontal deflection output circuit (124).

Description

Specification

Cathode ray tube device for preventing image distortion due to brightness change

The present invention relates to a cathode ray tube device represented by a television receiver ゃ computer display device, and more particularly to a technique for preventing image distortion caused by a change in luminance of a display pixel. Background art

In general, in a cathode ray tube device, the brightness of pixels displayed on a screen is changed by changing the amount of anode current flowing from the anode of the cathode ray tube toward the power source of the electron gun constituting the cathode ray tube. Is changed. The pixel brightness increases as the anode current increases, and decreases as the anode current decreases.

When the anode current flows, the output impedance of the flyback transformer causes a voltage drop according to the magnitude of the anode current. The anode voltage changes due to the voltage drop caused by the fly-pack transformer.

Since the speed of the electrons emitted from the force source depends on the anode voltage, the larger the anode current, the larger the voltage drop of the anode voltage and the lower the anode voltage. Slows down. If the speed of the electrons is slow, the amount of time required for the electrons to pass through the deflecting magnetic field increases, and the amount of deflection increases. By the mechanism described above, the amount of electron deflection increases as the brightness of the pixel displayed on the screen increases, and the amount of deflection decreases as the brightness decreases. As a result, the screen expands and contracts in the horizontal direction according to the brightness of the pixels.

As an example of displaying high-luminance pixels on a screen screen, a case where two rectangles having different luminances are superimposed on the screen screen will be described. FIG. 1 is a schematic diagram showing a screen screen in which two rectangles having different luminances are displayed in an overlapping manner.

In Fig. 1, the effective display area of the screen screen (the area where the phosphor is applied on the screen screen) 201 is a cross-hatch image that displays thin lines in the vertical and horizontal directions. 2 is displayed. In addition, a figure 203 with high brightness is displayed in the center of the effective display area 201.

Since the figure 203 has high luminance, the image whose size increases in the horizontal direction is distorted by the above-described mechanism. Due to this distortion, both the image of a chopstick, which is originally a straight line, and the image of a chopstick, which is originally a rectangle, are enlarged in the scanning direction.

Such image distortion also occurs in a conventional television receiver. This is not a practical problem because the electron beam is scanned to the outside of the effective display area, that is, the so-called reverse scan is performed.

However, in recent years, digital broadcasting and high-definition television (HDT

V: With the practical application of i-definition (television), the pitch of the phosphors applied to the screen (the interval between the phosphors) has been miniaturized. Larger anode currents are needed to obtain sufficient brightness from a small amount of phosphor.

As a result, the amount of image distortion due to the change in luminance (anode current) also increases, making it more noticeable.

In recent years, television receivers have been used as information terminals for displaying images such as personal computers.

In a television receiver, in order to display a computer image without loss, a so-called underscan must be performed, in which the area scanned by the electron beam is made smaller than the effective display area of the screen screen.

However, when underscanning is performed, the luminance change as described above occurs. This causes a problem that distortion of an image due to image formation becomes noticeable. In particular, in recent years, moving images such as MPEG (Motion Picture Experts Group) images have been increasingly displayed as computer images, and the fluctuation range of luminance has become larger and more frequent. Accordingly, the distortion of the image is also remarkable.

To solve such a problem, for example, a display device disclosed in Japanese Patent Application Laid-Open No. 11-169195 has been proposed. FIG. 2 is a functional block diagram showing a part of the functional configuration of the display device disclosed in this publication. As shown in the figure, the display device 5 includes a video circuit 50, a vertical deflection circuit 51, a cathode ray tube 54, and the like.

The video circuit 50 amplifies the video signal Video received by the video input terminal 501 to a cathode voltage, and supplies a force source electrode (not shown) provided in the electron gun 542 of the cathode ray tube 54. )).

The cathode ray tube 54 has a deflection yoke 541, which includes a vertical deflection coil and a horizontal deflection coil (both not shown).

The vertical deflection circuit 51 receives a vertical synchronization signal VD at a vertical synchronization signal input terminal 511 and supplies a vertical deflection current synchronized with the vertical synchronization signal VD to the vertical deflection coil.

The horizontal deflection circuit 52 includes a horizontal deflection output circuit 524, a horizontal size control circuit 525, and the like. The horizontal deflection circuit 52 receives the horizontal synchronization signal HD at the horizontal synchronization signal input terminal 52 1 and receives the horizontal size control signal VS at the horizontal size control signal input terminal 52 26. The horizontal deflection circuit 52 supplies a horizontal deflection current to the horizontal deflection coil.

The anode voltage supply circuit 53 detects the beam current from the cathode ray tube 54 and outputs a control signal to the horizontal deflection circuit 52. This adjusts the anode voltage and corrects screen distortion.

The anode voltage supply circuit 53 is composed of a flyback transformer 531, a beam current detection circuit 53, a time constant circuit 53, and a power supply voltage control circuit 5332. It has.

FIG. 3 is a circuit diagram showing a circuit configuration of the horizontal deflection output circuit 524, the horizontal size control circuit 525, and the anode voltage supply circuit 53 constituting the display device 5.

As shown in FIG. 3, the beam current detection circuit 534 includes a resistor R 5

0 is provided to detect a change in the amount of beam current that changes with a change in luminance and output a control signal according to the amount of change.

The time constant circuit 533 includes a transistor Tr50, resistance elements R51, R52, and a field effect capacitor C50.

The time constant circuit 533 receives the anode voltage detected by the beam current detection circuit 534, generates an anode voltage correction signal VEHC, and outputs the anode voltage correction signal VEH.C to the power supply voltage control circuit 532. Output to the horizontal size control circuit 525. At this time, the time constant circuit 533 functions as a rover filter, and generates the anode voltage correction signal VEHC based on the frequency of the received voltage.

The power supply voltage control circuit 53 2 includes transistors Tr 51, Tr 52, a field effect capacitor C 51, an operational amplifier OA 50, and resistance elements R 53, R 54, R 55, R 56, R 5 It has 7, R58, R59, R60 and R61. The power supply voltage control circuit 532 controls the anode voltage by adjusting the power supply voltage supplied to the transformer T50 forming the fly-pack transformer 531.

With such a configuration, the display device disclosed in the above publication reduces a change in screen size due to a change in luminance.

However, as is evident from FIG. 3, the display device according to the above publication has two transistors and a field effect capacitor only for the purpose of suppressing image distortion caused by a change in luminance. , One operational amplifier, and nine resistive elements, a complex anode voltage supply circuit that requires a number of components must be installed. This means In this sense, the technology disclosed in the conventional gazette is not a practical solution for eliminating such image distortion. hard.

The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide an inexpensive cathode ray tube device that suppresses a change in screen size and reduces image distortion regardless of a change in luminance. Aim. Disclosure of the invention

In order to achieve the above object, a cathode ray tube device according to the present invention is a cathode ray tube device that controls anode current to change the luminance of a pixel, and supplies an anode voltage provided in the cathode ray tube device. In the anode voltage supply circuit, a beam current detection circuit that detects an anode current, and an AC component of the anode current detected by the beam current detection circuit is extracted to detect a change amount of the anode current. It is characterized by including an AC component extraction circuit and a horizontal size control circuit that increases the horizontal deflection magnetic field as the detected anode current increases, and weakens the horizontal deflection magnetic field as the anode current decreases.

In this case, the beam current detection circuit may detect the anode current as a voltage.

As described above, if the horizontal size is controlled in accordance with the amount of change in the anode current, the number of components required for correcting the screen distortion is reduced and the cost required for correcting the screen distortion is reduced in comparison with the case of the conventional technology. Can be reduced. Further, the AC component extracting circuit extracts the AC component using a capacitor. By doing so, the AC component of the beam current can be detected at lower cost.

Further, the AC component extraction circuit may include an inversion circuit that inverts an AC component of the anode voltage extracted by the beam current detection circuit. With this configuration, the circuit configuration of the AC component extraction circuit is simpler. Therefore, the circuit cost of the AC component extraction circuit can be reduced.

Further, the cathode ray tube device according to the present invention is a cathode ray tube device for supplying an anode voltage boosted by a flyback transformer to the cathode ray tube, wherein the cathode ray tube device is inserted into a high voltage side ground wire of the flyback transformer. An anode current is detected by the resistive element, and a base electrode is connected to the flyback transformer side of the resistive element, and the anode voltage is inverted by a transistor whose emitter electrode is grounded. An alternating current component of the anode current extracted by a capacitor connected to the collector electrode of the transistor, an alternating current component extracting circuit for detecting a change amount of the anode current, and a negative current of the anode current detected by the alternating current component extracting circuit. The larger the increase, the stronger the horizontal deflection magnetic field, and the larger the decrease in the anode current, the weaker the horizontal deflection magnetic field. Characterized in that it comprises a's controller. As described above, the use of the capacitor can reduce the cost required for the AC component extraction circuit that detects the amount of change in the anode current.

It is further preferable that a variable resistance element connected to the electrode of the capacitor to which the transistor is not connected corrects a variation in a node current detected by the AC component extraction circuit. . In this way, it is possible to adjust the circuit error for each cathode ray tube device after the assembly of the device is completed. Therefore, particularly during mass production, the state of correction of image distortion can be adjusted at the time of shipment, so that a high-quality cathode ray tube device can be provided.

As described above, according to the present invention, since the intensity of the horizontal deflection magnetic field is adjusted by extracting the amount of change in the anode current, the cost for eliminating the image distortion caused by the change in luminance is reduced. be able to.

Therefore, in a CRT device in which the resolution is high and the amount of phosphor per pixel is small, the amount of beam current must be increased, and this is caused by the change in pixel brightness, that is, the change in anode current. Anode The problem of image distortion is likely to occur due to the large fluctuation range of the voltage, but the present invention is particularly effective in such a case. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram schematically showing an image displayed on the television receiver 1 when the performance evaluation is performed.

FIG. 2 is a functional block diagram showing a functional configuration of the display device disclosed in the conventional publication.

FIG. 3 is a circuit diagram showing a circuit configuration of a display device disclosed in a conventional publication, particularly showing a circuit related to correction of image distortion.

FIG. 4 is a functional block diagram showing functions of the television receiver according to the embodiment of the present invention, and particularly shows functions related to control of the amount of anode current.

FIG. 5 is a circuit configuration diagram showing a circuit configuration example of the anode voltage supply circuit 13, the horizontal deflection output circuit 124, and the horizontal size control circuit 125 in the television receiver 1.

FIG. 6 is a table showing circuit constants employed in the present embodiment, particularly circuit constants relating to the anode voltage supply circuit.

FIG. 7 is a table showing measurement results of distortion widths of the conventional television receiver and the television receiver 1 according to the present embodiment.

FIG. 8 is a circuit configuration in the case where a transformer is used instead of the transistor Tr 20 in the television receiver 1, and is a circuit diagram particularly showing the beam current detection circuit and the AC component extraction circuit.

FIG. 9 is a circuit diagram showing a configuration of a television receiver according to a modified example (3) of the present invention, in particular, a circuit configuration of a beam current detection circuit, an AC component extraction circuit, and a horizontal size control circuit. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a cathode ray tube device according to the present invention will be described with reference to the drawings, taking a television receiver as an example.

[1] Functional configuration of television receiver according to present embodiment

FIG. 4 is a functional block diagram showing functions of the television receiver according to the present embodiment, and particularly shows functions related to control of an anode current amount.

As shown in FIG. 4, the television receiver 1 includes a vertical deflection circuit 11 ゃ video circuit 10, and a cathode ray tube 14. In the television receiver 1, the horizontal deflection circuit 12 and the anode voltage supply circuit 13 prevent horizontal screen distortion caused by a change in luminance. . The cathode ray tube 14 is a cathode ray tube with a diagonal dimension of 80 cm (34 in.) And an aspect ratio of 4: 3, and vertically deflects the electron beam emitted from the electron gun 142. A deflection yoke 141 is provided which is deflected by a coil and a horizontal deflection coil (both not shown).

Further, the cathode ray tube 14 has an anode electrode (not shown), and receives an anode current supplied from the flyback transformer 13 1 at the anode electrode.

The video circuit 10 amplifies the video signal Video received from the video input terminal 101 to generate a cathodic voltage, and supplies the power source voltage to the electron gun 1 provided in the cathode ray tube 14. 4 Apply to the cathode electrode of 2 (not shown).

The vertical deflection circuit 11 receives a vertical synchronization signal VD at a vertical synchronization signal input terminal 11 1, generates a vertical deflection current synchronized with the vertical synchronization signal VD, and supplies the current to the vertical deflection coil. I do.

The horizontal deflection circuit 12 includes a horizontal oscillation circuit 122, a horizontal drive circuit 123, a horizontal deflection output circuit 124, and a horizontal size control circuit 125. The horizontal deflection circuit 12 receives a horizontal synchronization signal HD at a horizontal synchronization signal input terminal 12 1 and supplies a horizontal deflection current to the horizontal deflection coil. The horizontal size control circuit 125 receives the horizontal size control signal VS through the horizontal size control signal input terminal 126 and also receives the control signal from the anode voltage supply circuit 13. Then, the horizontal size control circuit 125 inputs the correction signal EW generated based on these signals to the horizontal deflection output circuit 124 to correct the horizontal deflection current.

When the horizontal deflection output circuit 124 corrects the horizontal deflection current, the intensity of the horizontal deflection magnetic field is corrected accordingly, so that the image distortion in the horizontal direction is corrected.

Here, the correction signal EW is a vertical period parabolic wave for correcting left and right pink distortion. The horizontal oscillation circuit 122, the horizontal drive circuit 123, and the horizontal deflection output circuit 124 are circuits corresponding to the circuits of the same name disclosed in the above-mentioned conventional publication.

The horizontal size control circuit 125 is also a circuit corresponding to the circuit of the same name disclosed in the above-mentioned conventional publication, but has a different circuit connection with the anode voltage supply circuit 13 as described later.

The anode voltage supply circuit 13 includes a flyback transformer 13 1, a beam current detection circuit 13 2, and an AC component extraction circuit 13 3. The flyback transformer 13 1 boosts the voltage supplied from the horizontal deflection output circuit 124 and applies it to the anode electrode of the cathode ray tube 14.

The beam current detection circuit 1332 is a circuit corresponding to the beam current detection circuit 534 according to the above-mentioned conventional publication, and detects an anode current.

The AC component extraction circuit 133 applies the anodic current detected as a voltage from the beam current detection circuit 132 to the AC component, that is, the change in the AC component, that is, the brightness (anode current amount). The change in the anodic current generated by the extraction is extracted.

Then, the AC component extraction circuit 133 outputs the extracted change in the anode current to the horizontal size control circuit 125 as a control signal.

[2] Circuit configuration of television receiver 1 FIG. 5 is a circuit configuration diagram showing the circuit configuration of the anode voltage supply circuit 13, the horizontal deflection output circuit ′ 124, and the horizontal size control circuit 125 in the television receiver 1.

As shown in FIG. 5, the primary side (low voltage side) of the flyback transformer T 20 is connected to the horizontal deflection output circuit 124. The secondary side (high voltage side) is connected to the anode electrode of the cathode ray tube via a diode D20. The diode D20 rectifies a voltage obtained by boosting a fly-pack pulse generated in the return period of the sawtooth current flowing through the horizontal deflection coil by the flyback transformer T20.

The other terminal on the secondary side of the flyback transformer T20 is connected to the beam current detection circuit 132. The beam current detection circuit 132 includes a resistance element R24, and detects the anodic current as a voltage by the resistance element R24. The detected anode current is output to the horizontal size control circuit 125 through the AC component extraction circuit 133.

The AC component extraction circuit 1 3 3 is a transistor Tr 20 and a capacitor C 2

0, and four resistance elements R20, R21, R22, and R23. The anode current detected as a voltage from the beam current detection circuit 132 is input to the resistance element R23.

The resistance element R23 is connected to the base electrode of the transistor Tr20. The emitter electrode of the transistor Tr20 is grounded via the resistor R22. The collector electrode of the transistor Tr20 is connected to the capacitor C20 and to the constant voltage source via the resistor R20.

As described above, the transistor Tr 20 forms an inverting amplifier circuit, inverts the change in the anode current detected by the beam current detection circuit 132 as a voltage, and directs the change to the capacitor C 20. Output.

The other electrode of the capacitor C20 is connected to a horizontal size control circuit 125 through a resistance element R21. The capacitor C 20 extracts the AC component of the anode current detected as a voltage, that is, the change in the anode voltage due to the change in the luminance (the amount of the anode current), inverted by the transistor Tr 20, Output to the horizontal size control circuit 125 through the resistance element R21. '

The horizontal size control circuit 125 includes an operational amplifier 0A20 and four resistance elements R25, R26, R27, and R28.

The inverting input terminal (1) of the operational amplifier OA20 is grounded via the resistor R27, and is connected to the output terminal of the operational amplifier 0A20 via the resistor R28. Constructs an inverting amplifier circuit. The output signal of the non-inverting amplifier circuit is input to the horizontal deflection output circuit 124.

The anode voltage detected by the beam current detection circuit 132 is input to the inverting input terminal (1) of the operational amplifier OA20 via the resistance element R25. The non-inverting input terminal (+) receives the horizontal size control signal VS via the resistance element R26, and receives the output of the anode voltage supply circuit 13 as well.

That is, a signal in which the variation of the anode voltage is superimposed on the horizontal size control signal VS is input to the non-inverting input terminal (+) of the operational amplifier OA20, and the signal is amplified by the non-inverting amplifier circuit. It is input to the horizontal deflection output circuit 124.

With the above configuration, if the AC component of the anode current detected by the AC component extraction circuit 133, that is, the amount of change indicates an increase in the anode current, the AC component extraction circuit 1 As the output voltage of 33 rises, the voltage applied to the non-inverting input terminal (+) of the operational amplifier OA20 rises, so that the output voltage of the horizontal size control circuit 125 rises. Therefore, since the horizontal deflection output circuit 124 increases the strength of the horizontal deflection magnetic field, the distortion of the image due to the decrease in the anode voltage due to the higher brightness of the pixel can be suppressed. Conversely, if a decrease in the anode current is detected, the output voltage of the AC component extraction circuit 133 drops and is applied to the non-inverting input terminal (+) of the operational amplifier OA20. Therefore, the output voltage of the horizontal size control circuit 125 decreases.

Therefore, since the horizontal deflection output circuit 124 weakens the strength of the horizontal deflection magnetic field, the distortion of the image due to the increase in the anode voltage due to the lower luminance of the pixel can be suppressed. Therefore, according to the configuration of the present embodiment, it is possible to prevent an image from being distorted due to a change in luminance of a pixel.

Here, circuit constants employed in the present embodiment, particularly circuit constants relating to the anode voltage supply circuit, are shown. FIG. 6 is a table showing circuit constants employed in the present embodiment, particularly circuit constants relating to the anode voltage supply circuit.

The amplitude of the control signal output to the horizontal size control circuit 125 can be adjusted by adjusting the resistance value of the resistance element R21.

That is, when the resistance value of the resistor R 21 is increased, the correction amount is reduced, and when the resistance value is reduced, the correction amount is increased. Therefore, when a resistance element having an appropriate resistance value is used in accordance with the correction amount. It is suitable.

[3] Performance evaluation

The following performance evaluation was performed on the television receiver 1 according to the present embodiment. FIG. 1 is a diagram schematically showing an image displayed on the television receiver 1 when the performance evaluation is performed.

As shown in FIG. 1, a cross hatch image 202 is displayed in the effective display area 201 of the television receiver 1. In addition, a white, high-brightness image 203 is displayed substantially at the center of the crosshatch image 202.

Since a large amount of anode current flows in the region where the rectangular image 203 is displayed, image distortion occurs due to the mechanism described above. Due to the distortion of this image, the cross hatch image 202, which should be a straight line, 08636 The portion of the rectangular image 203 that is the same as the horizontal scanning line is distorted.

In this performance evaluation, in order to measure the magnitude of this distortion, the overscan was stopped, and the entire crosshatch image 202 was displayed in the effective display area, including the part where the distortion was received. The amount of horizontal deflection is adjusted so that The adjustment of the amount of horizontal deflection is such that the portion where the crosshatch image 202 is widened in the scanning direction due to image distortion is just the left and right ends of the effective display area.

Under these conditions, the location where the horizontal scanning line is the same as the rectangular image 203 of the cross hatch image 202 (the widest point) and the location where the horizontal scanning line is not the same as the rectangular image 203 The distortion of the image was evaluated by comparing the horizontal size of the mouth hatch image 202 with (the least widened portion).

Specifically, the distances Wa and Wb from the left and right edges of the effective display area of the screen screen to the least widened portion of the crosshatch image 202 are measured, and the average value of these distances (W The degree of image distortion was evaluated by a + Wb) / 2. Hereinafter, this average value is referred to as a distortion width.

The following results were obtained by measuring the distortion width of the conventional television receiver and the television receiver 1 according to the present embodiment. FIG. 7 is a table showing the measurement results of the distortion width for the conventional television receiver and the television receiver 1 according to the present embodiment.

The conventional television receiver has a diagonal dimension of 8 Ocm (34 inches) and an aspect ratio similar to that of the television receiver 1 according to the present embodiment. It has a 4: 3 cathode ray tube.

As shown in the above table, according to the present embodiment, it is possible to reduce image distortion due to a change in luminance to a level that cannot be visually confirmed.

Further, the circuit configuration is much smaller than the display device disclosed in the above-mentioned conventional publication, and no expensive circuit elements are required, so that the display device is inexpensive. T JP2003 / 008636 Image distortion can be eliminated.

Although the invention of the present application has been described based on the embodiment, the invention of the application is not limited to the above-described embodiment, and the following modifications can be made.

(Modification)

(1) In the above embodiment, a fixed resistor having a constant resistance value is used for the resistor R 21, but instead, a variable resistor may be used for the resistor R 21. good.

The degree of image distortion caused by a change in luminance varies among individual television receivers and is not necessarily constant.

On the other hand, if a variable resistor is used for the resistance element R21, the resistance value of the folding element R21 can be adjusted individually after the television receiver is assembled. The distortion of the image can be eliminated regardless of the variation of each image.

(2) In the above-described embodiment, the transistor Tr20 is used to invert the anode current detected by the beam current detection circuit 132 as a voltage. A transformer may be used as described above.

FIG. 8 is a circuit diagram showing a circuit configuration when a transistor is used in place of the transistor Tr 20 in the television receiver 1, and particularly shows a circuit configuration of a beam current detection circuit and an AC component extraction circuit. is there.

As shown in FIG. 8, the beam current detection circuit 13 21 of the television receiver according to the present modification includes a resistor R 3, as in the beam current detection circuit 13 2 of the television receiver 1. At 0, the anode current is detected. The anode current detected by the beam current detection circuit 133 as a voltage is applied to an AC component extraction circuit 133 '.

The AC component extraction circuit 13 3 ′ includes a transformer T 30 and resistance elements R 31 and R 32. Transformer T30 has a coil wound in opposite directions on the primary side and the secondary side, and has a magnetic core. The resistance element R 31 is a fixed resistor, and is connected to the primary side of the transformer 30.

The resistance element R32 is a variable resistor, and is connected to the secondary side of the transformer Τ30. As described above, the transformer 30 and the resistance elements R31 and R32 constitute a series circuit as a whole.

Now, the anode current detected as the voltage applied from the beam current detection circuit 1321 is applied to the primary side of the transformer 30 via the resistance element R31.

On the secondary side of the transformer Τ30, only the AC component of the voltage applied to the primary side is output, and no DC component is output.

Also, as described above, since the primary and secondary sides of the transformer Τ30 are wound in the opposite directions, the primary side is applied to the secondary side of the transformer Τ30. A voltage obtained by inverting the AC component of the applied voltage is output.

The AC voltage output from the secondary side of the transformer Τ30 is stepped down by the resistor R32 and output to the horizontal size control circuit.

As described above, since the resistance element R32 is a variable resistor, it is used for final adjustment of image distortion due to fluctuations in the anode current after assembly of the television receiver. Can be

The effects of the present invention can also be obtained with the above configuration. Note that a transistor and a transistor usually have greatly different external dimensions, and the transistor is considerably smaller than the transistor. Therefore, if a reduction in the size of the entire circuit is desired, the transistor and the transistor are used as in the above embodiment. It is preferable to use a circuit configuration that uses.

(3) In the above modified example (2), a case was described in which a transformer was used in which the coils were wound in the opposite directions on the primary side and the secondary side. Is also good.

That is, instead of the transformer Τ30 in FIG. 8, the primary side and the secondary side It is assumed that a transformer having the same direction of coil winding is used in the above, and that the transformer is connected to the resistance elements R31 and R32 in the same manner as the transformer T30 in FIG. good.

FIG. 9 is a circuit diagram showing a circuit configuration of a television receiver according to the present modification, particularly showing a circuit configuration of a beam current detection circuit, an AC component extraction circuit, and a horizontal size control circuit.

As shown in FIG. 9, the AC component extraction circuit 13 3 ″ included in the television receiver according to the present modified example includes an antenna detected as a voltage by the beam current detection circuit 13 2 ′ ″. In response to the application of the lead current, the AC component is extracted and input to the horizontal size control circuit 125 ′.

At this time, the transformer T40 has the same winding direction on the primary side and the secondary side, so that the AC component of the voltage applied to the transformer T40 is inverted. Output to the secondary side without

The AC voltage output in this manner is stepped down by the resistance element R42 and then input to the horizontal size control circuit 125 '. In the present modification, the output voltage is input to the inverting input terminal (1) of the operational amplifier # A40. The effects of the present invention can also be obtained with the above circuit configuration. Even if the configuration other than the configuration according to the present modified example is adopted, if the AC component of the anode voltage is not inverted, the output of the AC component extraction circuit is output to the operational amplifier of the horizontal size control circuit. When inputting to the inverting input terminal (1) and inverting the AC component of the anode voltage, input the output of the AC component extracting circuit to the non-inverting input terminal (+) of the operational amplifier of the horizontal size control circuit. do it.

(4) In the above embodiment, the case where the output of the transistor Tr20 is input to the capacitor C20 as the configuration of the AC voltage extraction circuit has been described. May be.

In other words, the AC component may be extracted by the capacitor, and then inverted by the transistor. Can be.

When the configuration of the present modification is adopted, it is necessary to add a bias circuit. For this reason, when aiming for lower cost, it is preferable to adopt the circuit configuration according to the above embodiment.

(5) In the above embodiment, the case where the invention of the present application is applied exclusively to a television receiver has been described. However, the invention of the present application is not limited to this, and the cathode ray tube other than the television receiver is The effect can be obtained by applying the present invention to a device, for example, a display device for display of a display. Industrial applicability

The cathode ray tube device according to the present invention is effective in preventing image distortion caused by a change in luminance. .

Claims

The scope of the claims

1. Use a cathode ray tube device that controls the anode current to change the pixel brightness.

An anode voltage supply circuit for supplying an anode voltage provided in the cathode ray tube device, comprising: a beam current detection circuit for detecting an anode current; and an AC component of the anode current detected by the beam current detection circuit. An AC component extraction circuit for extracting and detecting a change amount of the anode current;

A horizontal size control circuit that strengthens the horizontal deflection magnetic field as the detected anode current increases, and weakens the horizontal deflection magnetic field as the anode current decreases increases

A cathode ray tube device comprising:

2. The cathode ray tube device according to claim 1, wherein the beam current detection circuit detects an anode current as a voltage.

3. The AC component extraction circuit extracts the AC component with a capacitor

The cathode ray tube device according to claim 1, characterized in that:

4. The AC component extraction circuit includes:

Inverting circuit for inverting the AC component of the anode voltage extracted by the beam current detecting circuit

The cathode ray tube device according to claim 3, characterized by comprising:

5. A cathode ray tube device for supplying an anode voltage boosted by a fly-pack transformer to a cathode ray tube,

The resistance element inserted in the high-voltage side ground wire of the flyback transformer To detect the anode current,

A base electrode is connected to the fly pack transformer side of the resistance element, an emitter electrode is grounded, and the anode voltage is inverted by the transistor.

The capacitor connected to the collector electrode of the transistor

-By extracting the AC component of the

An AC component extraction circuit for detecting the amount of change in the anode current;

A horizontal size control unit that strengthens the horizontal deflection magnetic field as the increase amount of the anode current detected by the AC component extraction circuit is larger, and weakens the horizontal deflection magnetic field as the decrease amount of the anode current is larger.

A cathode ray tube device comprising:

6. The variable resistance element connected to the electrode of the capacitor to which the transistor is not connected corrects the amount of change in the node current detected by the AC component extraction circuit.

The cathode ray tube device according to claim 5, characterized in that: