JP2003179770A - Circuit for correcting cross-pin cushion distortion of television receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distortion correction circuit used when cross-pin cushion distortion in appearance is different between the upper half face and the lower half face of the cathode-ray tube of a television receiver. <P>SOLUTION: A cross-pin cushion distortion correction circuit is more flexible and higher accurate in such a manner that a generation circuit 1 for a correction waveform of a horizontal rate in the upper half face and a generation circuit 2 for a correction waveform of a horizontal rate in the lower half face are provided as a device and that the correction waveforms are changed over with a switch 4 at a vertical center place. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal pincushion distortion correction circuit for a television receiver.

[0002]

2. Description of the Related Art As a conventional configuration of a horizontal pincushion distortion correction circuit of a television receiver, one horizontal pincushion correction waveform of a horizontal rate is generated, and the gain of the correction is set in the vertical direction. By controlling it, it is possible to cope with different lateral pincushion distortion amounts in the vertical direction.

[0003]

However, according to the prior art, the pincushion distortion correction is similar in shape to the distortion at any vertical position of the cathode ray tube when the distortion correction circuit is considered. It is configured on the assumption that. The geometrical distortion of the cathode ray tube is similar to that of the cathode ray tube, but the magnetic field distribution of the deflection yoke is unbalanced and dispersed. This tendency is particularly remarkable in a flat cathode ray tube and a cathode ray tube having a large deflection angle.

[0004]

In order to solve the above-mentioned problems, the present invention relates to a horizontal pincushion distortion correction circuit for a television receiver, which generates a required horizontal pincushion correction waveform 1 for the upper half of the cathode ray tube. A circuit for generating the required horizontal pincushion correction waveform 2 for the lower half of the cathode ray tube, a circuit for generating a characteristic for gain controlling the horizontal pincushion correction waveform in the vertical direction of the cathode ray tube, and the horizontal pincushion waveform and the gain control characteristic. It is characterized in that it is composed of a multiplier as an input and a switch for switching between the correction waveform 1 and the correction waveform 2 in the vertical center of the cathode ray tube. Memory for storing the required horizontal pincushion correction waveform 1 and the required horizontal pincushion for the lower half of the cathode ray tube A memory for storing the positive waveform 2,
The present invention is characterized in that a memory for storing a characteristic for controlling the gain of the lateral pincushion correction waveform in the vertical direction of the cathode ray tube is provided.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The invention according to claim 1 of the present invention is a horizontal pincushion distortion correction circuit for a television receiver, and a circuit for generating a required horizontal pincushion correction waveform 1 for the upper half surface of a cathode ray tube. , A required horizontal pincushion correction waveform 2 generation circuit for the lower half of the cathode ray tube, a characteristic generation circuit for gain control of the horizontal pincushion correction waveform in the vertical direction of the cathode ray tube, and the horizontal pincushion waveform and gain control characteristic are input. And a switch for switching between the correction waveform 1 and the correction waveform 2 at the vertical center of the cathode ray tube. The horizontal pincushion distortion of the upper half surface of the cathode ray tube is characterized by the following: The correction and the lateral pincushion distortion correction on the inferior surface can be independently corrected.

The invention described in claim 2 of the present invention is, in addition to the invention described in claim 1, a memory for storing a required lateral pincushion correction waveform 1 for the upper half surface of the cathode ray tube.
It is characterized in that a memory for storing a required horizontal pincushion correction waveform 2 for the lower half of the cathode ray tube and a memory for storing a characteristic for gain control of the horizontal pincushion correction waveform in the vertical direction of the cathode ray tube are provided. Therefore, the correction can be performed more flexibly and accurately, and the optimum correction can be provided for each display mode.

An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3.

(Embodiment 1) FIG. 1 is a block diagram of a horizontal pincushion distortion correction circuit of a television receiver according to a position embodiment of the present invention. FIG. 1 is a general conventional configuration diagram in which a block A and a block B surrounded by dotted lines are deleted. The configuration in which only the block B is deleted is the embodiment of claim 1. A configuration in which the block B is added and all are used is the embodiment of claim 2.

FIG. 2 shows a state of lateral pincushion distortion on a cathode ray tube surface, a correction waveform in the horizontal direction for correcting the distortion, and a gain control in the vertical direction. Figure 2
(A) is an image diagram of the distortion of the tube surface when the upper half surface and the lower half surface of the cathode ray tube have similar horizontal pincushion distortions. FIG. 2B is an image diagram of the distortion of the tube surface when the upper half surface and the lower half surface of the cathode ray tube have different lateral pincushion distortions.

FIG. 3 schematically shows how the horizontal pincushion distortion correction waveform is superimposed on the vertical deflection current.

In FIG. 1, reference numeral 1 is a circuit for generating a correction waveform of the horizontal rate of the upper half surface of the cathode ray tube. Reference numeral 2 is a circuit for generating a correction waveform of the horizontal rate of the lower half surface of the cathode ray tube. Reference numeral 3 is a circuit for generating a characteristic for controlling the gain of the vertical correction amount of the cathode ray tube. 4 is a switch. 5 is a multiplier. 6 is a vertical output circuit. 7 is a cathode ray tube. Reference numeral 8 is a deflection yoke. 9 is a memory.
10 is a memory. 11 is a memory.

The operation will be described with reference to FIGS.

First, the operation of the conventional correction circuit will be described.
FIG. 2A shows the state of lateral pincushion distortion. To correct this distortion, the correction waveform of the horizontal rate is superimposed on the vertical deflection current as shown in FIG. The waveform is generally a parabola-based form as shown in FIG. 2A, and various controls are applied to this to generate a desired waveform. The horizontal rate waveform generating circuit 1 in the upper part of FIG. 1 plays this role. Corresponding to the change of the horizontal pincushion in the vertical direction is realized by controlling the gain of one correction waveform of the horizontal rate in the vertical direction on the assumption that the shapes are similar to each other. The generation of this gain control characteristic curve is realized by the vertical gain control characteristic generation 3 in FIG.

In FIG. 1, the output from the upper horizontal rate waveform generation circuit 1 and the output from the vertical gain control characteristic generation 3 are input to the multiplier 5, and the horizontal and vertical total horizontal pincushion distortion correction waveforms are input. Is being generated. This is input to the vertical output circuit 6 and superimposed on the vertical deflection current to obtain the waveform shown in FIG. Thus, conventionally, lateral pincushion distortion correction is realized.

Next, the invention described in claim 1 will be described.

With the flattening of cathode ray tubes and the increase in deflection angle in recent years, non-uniformity of distortion due to unbalance and variation of the magnetic field distribution of the deflection yoke is likely to appear on the tube surface. For example, as shown in FIG. As shown in (B), the shape of the distortion of the horizontal rate at the upper part of the tube surface and the shape of the distortion at the lower part may differ by more than the allowable level. In order to correct such a lateral pincushion distortion distribution, a distortion correction waveform generating circuit for the upper half surface and a distortion correction generating circuit for the lower half surface are required respectively.

In FIG. 1, a configuration in which there are two horizontal rate waveform generating circuits 1 on the upper side and two horizontal rate waveform generating circuits on the lower side corresponds to that. The switch 4 of FIG. 1 is used to switch between the upper distortion correction waveform and the lower distortion correction waveform. The switching timing is in the central portion in the vertical direction. The reason is that it is a boundary between the upper half surface and the lower half surface, and that the correction gain is zero in the central portion, so that discontinuity due to switching of different waveforms does not occur. As described above, the corrected horizontal rate correction waveform and the vertical gain control characteristic waveform are input to the multiplier 5 to generate a horizontal and vertical total horizontal pincushion distortion correction waveform. In this way, lateral pincushion distortion correction is realized when the distortion states of the upper half surface and the lower half surface are different.

Next, the invention described in claim 2 will be described.

The present invention is obtained by adding the contents of a block B surrounded by a dotted line to the invention described in claim 1 in FIG. In the block B, memories 9, 10 and 11 are installed. Each of these memories is a memory in which the memory 9 stores the correction waveform of the horizontal pincushion horizontal rate of the upper half of the cathode ray tube, and the memory 10 stores the correction waveform of the horizontal pincushion horizontal rate of the upper half of the cathode ray tube. The memory 11 is a memory that stores a characteristic curve for vertical gain control. By using these memories, it is possible to flexibly create and store each correction waveform.

As a result, more flexible and accurate lateral pincushion distortion correction can be realized than ever before. Further, even when the screen display modes are different, the waveforms corresponding to the respective screen display modes can be generated and stored. As a result, even when the screen display modes are different, lateral pincushion distortion correction with higher flexibility and accuracy can be realized.

[0021]

As described above, according to the horizontal pincushion distortion correction circuit of the television receiver of the present invention, the circuit for generating the required horizontal pincushion correction waveform 1 for the upper half surface of the cathode ray tube and the horizontal pincushion distortion correction circuit for the lower half surface of the cathode ray tube are provided. A generation circuit for the required lateral pincushion correction waveform 2, a characteristic generation circuit for gain control of the lateral pincushion correction waveform in the vertical direction of the cathode ray tube, and a multiplier having the lateral pincushion waveform and the gain control characteristic as inputs. A switch for switching between the correction waveform 1 and the correction waveform 2 at the vertical center of the cathode ray tube, a memory for storing the required horizontal pincushion correction waveform 1 for the upper half surface of the cathode ray tube, and a required horizontal pincushion correction for the lower half surface of the cathode ray tube. Memory for storing waveform 2 and the horizontal pincushion correction wave in the vertical direction of the cathode ray tube. The by apparatus and a memory for storing the gain control characteristics, a more flexible and accurate horizontal pincushion distortion correction can be realized regardless of the screen display mode.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a horizontal pincushion distortion correction circuit of a television receiver according to an embodiment of the present invention.

FIG. 2 is an image diagram showing a state of horizontal pincushion distortion on a cathode ray tube surface, a horizontal correction waveform for correcting the distortion, and a vertical gain control.

FIG. 3 is an image diagram schematically showing how a horizontal pincushion distortion correction waveform is superimposed on a vertical deflection current.

[Explanation of symbols]

1 Horizontal-rate correction waveform generation circuit for upper half of cathode ray tube 2 Horizontal-rate correction waveform generation circuit for lower half of cathode ray tube 3 Characteristic generation circuit for gain control of vertical correction amount of cathode-ray tube 4 Switch 5 Multiplier 6 Vertical output Circuit 7 CRT 8 Deflection yoke 9 Memory 10 Memory 11 Memory

Claims (2)

[Claims] 1. A horizontal pincushion distortion correction circuit for a television receiver, comprising: a circuit for generating a required horizontal pincushion correction waveform 1 for the upper half of the cathode ray tube and a required horizontal pincushion correction waveform 2 for the lower half of the cathode ray tube. A generation circuit, a generation circuit of a characteristic that controls the gain of the horizontal pincushion correction waveform in the vertical direction of the cathode ray tube, a multiplier that inputs the horizontal pincushion waveform and the gain control characteristic, and a center of the vertical direction of the cathode ray tube. A horizontal pincushion distortion correction circuit for a television receiver, comprising a switch for switching between the correction waveform 1 and the correction waveform 2. 2. In addition to the invention of claim 1, a required lateral pincushion correction waveform 1 for the upper half surface of a cathode ray tube.
A memory for storing the required horizontal pincushion correction waveform 2 for the lower half of the cathode ray tube, and a memory for storing the characteristics for gain control of the horizontal pincushion correction waveform in the vertical direction of the cathode ray tube. , A horizontal pincushion distortion correction circuit for a television receiver.