JP3316282B2 - Television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
More particularly, the present invention relates to a television receiver having a function of displaying a 16: 9 image by controlling a deflection current of an image having an aspect ratio of 4: 3.

[0002]

2. Description of the Related Art In recent years, a broadcasting system called high-definition broadcasting has been proposed in order to obtain a more realistic sensation. This broadcast has 1125 scanning lines and a 16: 9 aspect ratio screen.

On the other hand, in the current NTSC broadcasting, the screen aspect ratio is 4: 3. For this reason, current television receivers use one of the above-mentioned high-definition broadcasts.
The 6: 9 screen cannot be displayed.

In order to receive a high-definition broadcast and view an image with a sense of reality, the aspect ratio is 16:16.
A television receiver with nine screens has become necessary. For this reason, recently, a television receiver has been proposed as shown on page 33 of the October issue of the monthly Videocom issued by AVCC.

A television receiver having a 16: 9 screen has a function of receiving not only a high-definition broadcast but also an existing NTSC broadcast. When receiving the current NTSC broadcast, there is a display method as shown in FIG. 3 on a 16: 9 television receiver. That is, for the 16: 9 screen, for example, as shown in FIG. 3, there is a method (A) for normally displaying a 4: 3 video as it is.

On the other hand, a so-called squeeze mode in which a high-definition broadcast is converted to 4: 3 video and a vertically elongated screen is used, and the squeeze screen is stretched to a 16: 9 screen as shown in FIG. There is a way to display.

As described above, when a 4: 3 image is converted to a 16: 9 image, it is necessary to increase the size in the horizontal direction, and to obtain an image as shown in FIG. It becomes.

In order to increase the size in the horizontal direction, the DC voltage applied to the pincushion (PC) distortion correction circuit of the horizontal deflection circuit is changed. Further, since the image on both sides of the screen is distorted by stretching the image, the capacitance of the S-character correction capacitor is changed.

In the case of displaying the 4: 3 image as it is, since the deflection angle is small, the range of the correction amount of the PC distortion correction can be small, and the variable range can reduce the variation of components in the deflection circuit. Since only adjustment is required, the variable range can be small.

However, in a television receiver having a function of enlarging an image of 16: 9 as described above, a large deflection current is required to switch the screen size, as described above, so that a PC
The variable range of distortion correction must be larger than before.

On the other hand, when a portion of the conventional 4: 3 image shown in FIG. 3A has a high luminance (for example, an image portion of a center circle), a high-voltage fluctuation occurs in that portion, which causes image bending. Become. (Although the image curvature in this case is not so noticeable visually) On the other hand, since the influence of the high-voltage fluctuation becomes larger as the screen becomes longer in the horizontal direction, 16 as shown in FIG.
In the image No. 9, there is a problem that the image curvature is large and conspicuous.

[0012]

According to the present invention, in order to solve the above-mentioned problems, when a 4: 3 image is converted to a 16: 9 image, image bending due to high voltage fluctuation due to high luminance occurs. It is an object of the present invention to provide a television receiver which is not provided.

[0013]

According to the present invention, a horizontal output transistor (TR1) driven by a horizontal output pulse generated by a horizontal synchronizing signal, a first resonance capacitor (C1), and a cooperative operation therewith. A second resonance capacitor (C2), a first damper diode (D1) and a second damper diode (D2) operating in cooperation therewith, a horizontal deflection coil (DY) acting to be driven to be deflected by a deflection current, The S-shaped correction capacitor (C3) and the dummy coil (L) connected in series to the deflection coil (DY)
1) and a second correction capacitor (C5) connected in series between the dummy coil (L1) and a ground point, the television receiver having a horizontal deflection circuit, (C3) a capacitor (C4) arranged in parallel with (C3) and a capacitor (C4) and a switch (SW) in series, and a parabolic wave created from the synchronization signal. A pincushion distortion correction voltage generating means (1) for generating a cushion distortion correction voltage and AC from a high voltage of a high voltage generating circuit (3) obtained from a flyback transformer of the television receiver.
A high voltage fluctuation AC voltage generating means for extracting the component and ABL control voltage obtained from an ABL control voltage generating circuit (2) for limiting the beam current of the cathode ray tube.
The pincushion distortion correction voltage is added to a voltage obtained by adding an AC voltage from the second high-voltage fluctuation AC voltage generating means and the second high-voltage fluctuation AC voltage generating means for extracting the C component. High voltage fluctuation information generating means for applying a voltage to the connection point between the dummy coil (L1) and the second correction capacitor (C2); and the pin cushion. In order to raise the DC level of the distortion correction voltage, the DC voltage is added to the high voltage fluctuation information
Capacitor (C3) in parallel with the character correction capacitor (C3)
4) A control device for controlling the switch so that the switch is connected to the television receiver.

[0014]

According to the present invention, by adopting the above-described structure, the 4: 3
At the same time as switching from the image display to the 16: 9 image display, high-voltage fluctuation information is added to the PC correction voltage to prevent image bending.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of the present invention, where T1 is a horizontal output transistor, C1 is a resonance capacitor, D1 is a damper diode, C3 and C4 are S-shaped correction capacitors, DY is a horizontal deflection coil, C2 is a second resonance capacitor, D2 is a second damper diode, L1 is a dummy coil, C5 is a second
Is a switch, and is a horizontal deflection circuit having the above configuration.

L2 is a choke coil, T2, T3
Are transistors for level conversion, R1, R2, R3, R
4, R5 and R7 are resistors, C6 and C7 are AC cut capacitors, and T4 is a switching transistor.

1 is a PC correction voltage generation circuit, 2 is an ABL control voltage generation circuit, 3 is a high voltage generation circuit, and 4 is a control circuit.

Next, the operation will be described. In FIG. 1, a horizontal drive pulse is supplied to the base of a horizontal output transistor T1, and a deflection current flows through a horizontal deflection coil DY to deflect a beam current. At this time, a parabolic wave is output from the PC correction voltage generation circuit 1 and applied between the coil L1 and the capacitor C5 via the transistors T2 and T3.
C distortion correction can be performed. Such a point is described in Japanese Patent Publication No. 57-39.
It is publicly known as proposed in Japanese Patent Publication No. 102-102.

The amplitude of the horizontal deflection current can be varied by changing the DC level of the PC correction voltage. on the other hand,
The correction due to the image bending can be corrected by adding the high voltage fluctuation information to the PC correction voltage.

Therefore, in the present invention, the ABL control voltage and the high voltage from the FBT (flyback transformer) are added to the PC correction voltage as the high voltage fluctuation information. The ABL control voltage may be, for example, the one described on page 139 of “HNK Color Television Textbook (above)”, edited by The Japan Broadcasting Corporation, published on April 1, 1983.

First, when the 4: 3 image is to be displayed as it is, the control circuit 4 turns on the transistor T4 and inserts the resistor R5 between the ground, so that the PC correction voltage generation circuit 1 By lowering the DC level of the PC correction voltage, the horizontal amplitude is reduced and the deflection angle is reduced.

Then, the AC component of the ABL control voltage from the ABL control voltage generation circuit 2 is added to the PC correction voltage,
Further, the fluctuation of the high voltage is obtained from the high voltage generating circuit 3 and the AC component is added to correct the image bending.

For example, if there is a high luminance portion, the ABL control current decreases and the AC component of the PC correction voltage decreases (as shown by the dotted lines in FIGS. 3B and 3D). Then, by increasing the AC level of the PC correction voltage via the transistors T3 and T2, the AC level of the horizontal deflection coil DY decreases and the amplitude decreases. Also, the PC correction voltage is applied to the information from the high voltage circuit 3 (same operation as ABL),
Reduce the amplitude.

On the other hand, the control circuit 4 turns on the switch SW to increase the capacitance of the S-curve correction capacitor and reduce the amount of S-curve correction.
4 in parallel.

Next, when the image is expanded to 16: 9, the control circuit 4 turns off the transistor T4, increases the DC level of the PC correction voltage, and increases the deflection angle. At the same time, the ABL control voltage and the high voltage information can be added to the PC correction voltage to prevent image bending.

The control circuit 4 turns off the switch SW to increase the amount of correction for the S-shape correction, leaving only the S-shape correction capacitor C3.

According to the above, the DC level of the PC correction voltage is varied according to the state of the screen, and at the same time, high-voltage information is added to the PC correction voltage to prevent image bending.

Next, a second embodiment is shown in FIG. The difference from the embodiment of FIG. 1 is that a resistor R6 and a power supply + B are arranged at the collector of the transistor T4. In the embodiment shown in FIG. 2, a DC bias is applied to the collector of the transistor T4 via the resistor R6, so that the variation range of the horizontal deflection amplitude can be increased.

The high voltage fluctuation information includes ABL information and FB
The reason that both the information from T are added is that the ABL information can be easily derived, but the response is an average response and cannot be an immediate response. On the other hand, since the information from the FBT is responsive, both pieces of information are input.

In addition, as the high-voltage fluctuation information, an RGB output which is an output of a video signal to a cathode ray tube may be added, and output as high-voltage fluctuation information when the output is higher than a certain set value. . Further, the high-voltage fluctuation information may be added together with the high-voltage fluctuation information from the ABL and the FBT and output.

[0031]

According to the present invention, according to the state of the screen, P
Since the horizontal deflection amplitude can be changed by changing the DC level by the C correction voltage, P in each screen state can be changed.
The variable range of the C correction voltage can be made the same, and at the same time, by adding high-voltage information to the PC correction voltage, there is an effect that image bending can be more accurately prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram for explaining a conventional operation.

[Explanation of symbols]

 Reference Signs List 1 PC correction voltage generation circuit 2 ABL control voltage generation circuit 3 High voltage generation circuit 4 Control circuit T1 Horizontal output transistor C1 Resonance capacitor D1 Damper diode C3 Damper diode C4 S-shaped correction capacitor DY Horizontal deflection coil C2 Second resonance capacitor D2 Second Damper diode L1 Dummy coil C5 Second correction capacitor SW switch L2 Choke coil T2 Level conversion transistor T3 Level conversion transistor R1 Resistance R2 Resistance R3 Resistance R4 Resistance R5 Resistance R7 Resistance C6 AC cutting capacitor C7 AC cutting capacitor T4 Switching Transistor

Continuation of the front page (56) References JP-A-63-308477 (JP, A) JP-A-5-236383 (JP, A) JP-A-3-70270 (JP, A) JP-A-5-297816 (JP) JP-A-63-281571 (JP, A) JP-A-4-120977 (JP, A) JP-A-4-178075 (JP, A) JP-A-2-86371 (JP, A) 60-223380 (JP, A) JP-A-63-28176 (JP, A) JP-A-2-200063 (JP, A) JP-A-3-48967 (JP, U) JP-A-4-105576 (JP, A) U) Hikaru 1-177662 (JP, U) International Publication 93/9633 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 3/23 H04N 3/27

Claims (1)

(57) [Claims] 1. A horizontal output transistor (TR1) driven by a horizontal output pulse generated by a horizontal synchronization signal.
A first resonance capacitor (C1) and a second resonance capacitor (C2) operating in cooperation therewith; a first damper diode (D1) and a second damper diode (D2) operating in cooperation therewith; A horizontal deflection coil (DY) acting to be deflected by a current and an S-shaped correction capacitor (C) connected in series to the horizontal deflection coil (DY)
3), the dummy coil (L1), and the dummy coil (L
1) and a television receiver provided with a horizontal deflection circuit including a second correction capacitor (C5) connected in series between a ground point and a second correction capacitor (C5), which is disposed in parallel with the S-shaped correction capacitor (C3). A capacitor adding means for correcting an S-character, comprising a series circuit of a capacitor (C4) and a switch (SW); a pin for generating a parabolic wave from a synchronization signal to generate a pincushion distortion correction voltage at an end of the dummy coil Cushion distortion correction voltage generating means (1), first high-voltage fluctuation AC voltage generating means for extracting an AC component from a high voltage of a high voltage generating circuit (3) obtained from a flyback transformer of a television receiver, and a cathode ray tube High voltage fluctuation AC voltage for extracting an AC component from the ABL control voltage obtained from the ABL control voltage generation circuit (2) for limiting the beam current of Generating means, the first high-voltage fluctuation AC voltage generating means, and the second high-voltage fluctuation AC
A high voltage fluctuation information generating means for adding the pincushion distortion correction voltage to a voltage obtained by adding the AC voltage from the voltage generating means, and an output of the high voltage fluctuation information generating means to the dummy coil (L1) and a second correction capacitor ( C2) a high-voltage fluctuation information applying means for applying a DC voltage to the high-voltage fluctuation information generating means to increase the DC level of the pincushion distortion correction voltage, and at the same time, the S-shaped correction capacitor (C3 ) And control means for controlling the switch so that the capacitor (C4) is connected in parallel with the television receiver.