JPH05145781A - Rotation distortion correcting method for crt image, deflecting circuit for crt and image display device - Google Patents

Abstract

PURPOSE:To easily eliminate a rotation distortion by decomposing it into a parallelogram distortion in which one of a horizontal axis and a vertical axis of a display area is inclined against the reference axis of a besel frame, and correcting the inclination of the horizontal axis and the vertical axis of a display screen by adjusting vertical and horizontal deflecting currents, respectively. CONSTITUTION:When a modulated wave signal VC is inputted to a vertical deflecting circuit 15, the deflecting current VD0 of a reference waveform is modulated in accordance with the modulated wave signal, and modulated to a waveform on which a modulated wave is superposed. Thus, an electron beam is scanned, while being deflected by prescribed width in the vertical direction at every one piece of horizontal scanning line by a superposed saw tooth wave of a short period. When this phenomenon is looked at with regard to a horizontal scan of the electron beam, each horizontal scanning line rotates against a reference horizontal axis by width by which the electron beam is deflected in the vertical direction, and a parallelogram distortion is eliminated and corrected. A direction and an angle of its rotation depend on polarity and the amplitude value of the superposed modulated wave. Accordingly, an inclination is corrected by adjusting it in accordance with the direction and magnitude of an inclination of a horizontal axis of a display area to the reference horizontal axis.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a CRT (Cathode Ray T
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device using a ube), an image display device such as a television receiver, and more particularly to an image display device having a deflection circuit having a rotation distortion correction function of a CRT display screen.

[0002]

2. Description of the Related Art Image display devices such as CRT display devices have been developed with the development of microprocessors such as CAD and CA.
It is used in many fields such as M and workstations. In particular, in recent years, in order to process accurate and precise figures and drawings, CRT display devices have become more and more highly precise, and it is required that images be displayed at predetermined correct positions. ing.

The display screen section of an image display device using a CRT has a CRT mounted and fixed on a rectangular frame.
A rectangular decorative frame called a bezel is attached to the outer edge of the front surface of the image. Generally, an image is displayed in a rectangular display area (raster area) set inside the bezel frame.

[0004]

However, when the CRT and the bezel are attached with their relative positions deviating from the design standard when the display screen is assembled, the display area is horizontally or vertically oriented with respect to the bezel frame. It is displayed with a shift to or a relative rotation. In such a case, there are inconveniences such as that the display contents of the peripheral portion of the display area are hidden by the bezel, or the display feels uncomfortable.

The displacement of the display area in the horizontal or vertical direction is adjusted by adjusting the direct current component of the deflection current flowing in the horizontal or vertical deflection coil even after assembly, as is conventionally done. It can be easily corrected by aligning the center of with the center of the bezel frame.

However, the phenomenon in which the display area is rotated and displayed relative to the bezel frame (hereinafter referred to as low tension distortion) cannot be easily corrected. That is, after the image display device is assembled, the CRT is energized to display an image, and the presence or absence of rotation distortion and the degree of distortion are first checked. Next, turn off the image display, loosen the bezel's mounting screw to adjust the mounting angle, re-tighten the screw, energize the CRT again to display an image, and check for rotation distortion. Since the work must be repeatedly executed, there is a problem that the work efficiency is extremely low.

The low tension strain may be caused by the displacement of the mounting position of the CRT and the bezel as described above, or by the displacement of the mounting angle of the deflection yoke or the influence of the geomagnetism. Further, the rotation distortion includes parallelogram distortion that occurs when only one of the horizontal axis and the vertical axis of the display area rotates in addition to the case where the entire display area rotates.

As a method for easily correcting the rotation tension distortion as described above, conventionally, a method for providing a rotation distortion removing coil on a deflection yoke and adjusting the current flowing through the coil to correct the rotation distortion is actually used. 2-67
It is proposed in Japanese Patent No. 549.

However, according to the technique disclosed in the above publication, it is necessary to use a deflection yoke provided with a special rotation distortion correction coil, so that there is a problem that the cost is significantly increased.

The above-mentioned problem also occurs in a television receiver as well. That is, the displayed image is hidden by the frame of the peripheral portion, or the image to be displayed horizontally or vertically is tilted, which causes inconvenience.

An object of the present invention is to provide a rotation distortion correction method for removing rotation distortion of a CRT screen without using a rotation distortion correction coil, a CRT deflection circuit to which the method is applied, and an image display provided with the deflection circuit. To provide a device.

[0012]

In order to achieve the above object, the present invention decomposes rotation distortion into parallelogram distortion in which one of a horizontal axis and a vertical axis of a display area is inclined with respect to a reference axis of a bezel frame. Then, the inclination of the horizontal axis and the vertical axis of the display screen is corrected by adjusting the vertical and horizontal deflection currents, respectively.

That is, first, the sawtooth current is superposed on the sawtooth vertical deflection current flowing through the vertical deflection coil of the CRT in synchronization with the horizontal synchronizing signal, and the polarity and amplitude value of the sawtooth current are used as a reference. The tilt of the horizontal axis of the display image is corrected by adjusting according to the direction and size of the tilt of the horizontal axis of the display image with respect to the horizontal axis.

Secondly, a sawtooth current is superposed on the sawtooth horizontal deflection current flowing through the horizontal deflection coil of the CRT in synchronism with the vertical synchronizing signal, and the polarity and amplitude value of the sawtooth current are relative to the reference vertical axis. The vertical axis tilt of the display image is corrected by adjusting according to the direction and size of the vertical axis tilt of the display image.

Rotational distortion can be corrected by combining the first and second correction methods.

The rotation distortion correction method of the present invention can be realized by configuring a CRT deflection circuit as follows.

The CRT deflection circuit of the present invention comprises a horizontal deflection circuit which supplies a sawtooth horizontal deflection current to the horizontal deflection coil of the CRT in synchronization with the horizontal synchronization signal, and a vertical deflection of the CRT in synchronization with the vertical synchronization signal. A vertical deflection circuit that supplies a sawtooth-shaped vertical deflection current to the coil; and a modulation wave generation circuit that generates a sawtooth-shaped first modulation wave signal that is synchronized with the horizontal synchronization signal.
A first adjusting circuit for variably setting the polarity and amplitude value of the first modulated wave signal, and a second modulated wave generating circuit for generating a sawtooth-shaped second modulated wave signal synchronized with the vertical synchronizing signal. , A second that variably sets the polarity and amplitude value of this second modulated wave signal
Adjusting circuit, and the vertical deflection current is modulated by the first modulation wave signal, and the horizontal deflection current is modulated by the second modulation wave signal.

In this case, the horizontal deflection circuit is
When a horizontal centering circuit for controlling the ground potential of the deflection coil to adjust the horizontal center of the display screen is provided, the control output of the horizontal centering circuit is modulated by the second modulated wave signal to generate the horizontal deflection current. Can be modulated.

Further, the first and second modulated wave generation circuits each have a sawtooth wave generation circuit for generating a sawtooth wave synchronized with a horizontal / vertical synchronizing signal, and a coefficient to the output of each sawtooth wave generation circuit. And a multiplier for multiplying. In this case, the cycle of the sawtooth-shaped modulated wave is made to coincide with the cycle of the horizontal / vertical synchronizing signal to be synchronized.

Further, the first and second adjusting circuits can be integrally provided. In this case, the configuration includes a coefficient generation circuit that generates a variable level coefficient signal having polarity, and a coefficient distribution circuit that outputs the coefficient signal to the multiplier as the coefficient via a switch and an adjustment resistor, respectively. can do. It is preferable to use a variable resistor as the adjustment resistor because adjustment can be performed in response to a difference in inclination of the horizontal axis / vertical axis and a difference in aspect ratio of the display area.

By applying the deflection circuit of the present invention to the deflection circuit of a CRT display device and a television receiver,
It is possible to eliminate parallelogram distortion and rotation distortion.

[0022]

With the above structure, the object of the present invention is achieved by the following functions. First, the sawtooth-shaped vertical deflection current is superimposed on the sawtooth-shaped current having a short period that matches the period of the horizontal synchronizing signal, so that the electron beam is generated by the superimposed sawtooth-shaped current having a short period on each horizontal scanning line. , It is scanned while being swung with a constant width in the vertical direction. Looking at this phenomenon from the viewpoint of horizontal scanning of the electron beam, each horizontal scanning line is tilted with respect to the reference horizontal axis by the width in which the electron beam is vertically swung. The direction and angle of the inclination depend on the polarity and amplitude value of the superimposed sawtooth current. Therefore, the inclination of the horizontal axis of the display area can be corrected by adjusting the polarity and amplitude value of the sawtooth current to be superimposed according to the direction and magnitude of the inclination of the horizontal axis of the display area with respect to the reference horizontal axis.

Next, a sawtooth current synchronized with the vertical synchronizing signal is superimposed on the sawtooth horizontal deflection current flowing through the horizontal deflection coil of the CRT, as in the case of the above horizontal axis tilt correction. , All the plurality of horizontal scanning lines are sequentially displaced in the horizontal direction by the superimposed sawtooth wave having a long period. As a result, the vertical axis of the display area is tilted at a constant angle. The direction and angle of the inclination depend on the polarity and amplitude value of the superimposed sawtooth current. Therefore, by adjusting the polarity and amplitude value of the superimposed sawtooth current according to the direction and magnitude of the inclination of the vertical axis of the display area with respect to the reference vertical axis,
The tilt of the vertical axis of the display area can be corrected.

By combining these two correction methods, the rotation distortion can be corrected.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of an embodiment of the image display device of the present invention. The rotation distortion correction method of the present invention is applied to the image display device of this embodiment. As shown in the figure, the image display device of the present embodiment is a display device using a CRT.

Image data (RED, GREEN, BLU
E) is input to the video amplifier circuit 1 in synchronization with the clock pulse synchronized with the horizontal synchronizing signal (pulse) H. The video amplifier circuit 1 amplifies the input image data to a predetermined voltage and outputs it to the electron gun of the CRT 2. The neck portion 3 of the CRT 2 is provided with a deflection yoke 4 that deflects the electron beam emitted from the electron gun. The deflection yoke 4 is wound with a horizontal deflection coil 6 for deflecting and scanning the electron beam in the horizontal direction of the CRT tube surface 5 and a vertical deflection coil 7 for deflecting and scanning the electron beam in the vertical direction of the CRT tube surface 5. It has been turned. One ends of the deflection coils 6 and 7 are grounded via capacitors 8 and 9, respectively. The high voltage generation circuit 10 generates an anode voltage (for example, 27 kV) of the CRT 2 according to the input horizontal synchronizing signal H.

Next, the configuration of the deflection circuit according to the features of the present invention will be described. The deflection circuit includes a horizontal deflection circuit 11, a horizontal deflection modulated wave generation circuit 12, and a horizontal centering circuit 13.
A vertical deflection modulation wave generation circuit 14 and a vertical deflection circuit 15
And an adjusting circuit 16. As is well known, the horizontal deflection circuit 11 supplies a horizontal deflection current HS ₀ having a reference waveform to the horizontal deflection coil 6 in accordance with the horizontal synchronizing signal H. As is generally known, the horizontal centering circuit 13 controls the voltage of the ground side terminal of the horizontal deflection coil 6 to control the center level of the sawtooth horizontal deflection current. Thereby, the horizontal center of the display area can be moved and adjusted to the left and right. As is well known, the vertical deflection circuit 15 basically supplies a vertical deflection current VD ₀ having a reference waveform to the vertical deflection coil 7 in accordance with a vertical synchronizing signal (pulse) V. Further, although not shown, a vertical centering circuit is incorporated in the vertical deflection circuit 15.

The horizontal deflection modulation wave generation circuit 12 is a sawtooth modulation wave signal H which is synchronized with the vertical synchronization signal V and has the same period.
Generate C. The polarity of the modulated wave signal HC can be inverted, and its amplitude value can also be adjusted. The vertical deflection modulation wave generation circuit 14 generates a sawtooth modulation wave signal VC that is synchronized with the horizontal synchronization signal H and has the same cycle. The polarity of the modulated wave signal VC can be inverted, and its amplitude value can also be adjusted. These modulated wave signals HC,
The polarity and amplitude value of VC are variably set by the adjusting circuit 16. The adjusting circuit 16 has operation power sources + Vcc and -Vcc.
It is configured to include a sliding resistor 17 connected to, an amplifier circuit 18 for amplifying the output voltage of the resistor 17, and output resistors 19 and 20 connected to the output of the amplifier circuit 18. Then, the signals K ₁ and K ₂ for adjusting the polarity and the amplitude value of the modulation wave are output to the horizontal deflection modulation wave generation circuit 12 and the vertical deflection modulation wave generation circuit 14 through the output resistors 19 and 20, respectively. That is, by adjusting the position of the slider of the sliding resistance 17, the polarities and amplitude values of the modulated wave signals HC and VC are adjusted. In addition, the resistor 19,
Reference numeral 20 is an adjustment resistor for adjusting the rotational movement amount of the display area in the horizontal direction and the vertical direction. For example, the signals K ₁ and K ₂
Set the ratio of to match the aspect ratio of the display area. Variable resistors may be used as the resistors 19 and 20.

The configuration of a specific embodiment of the horizontal deflection modulation wave generation circuit 12 and the vertical modulation wave generation circuit 14 is shown. As shown in the figure, both are composed of integrators 12A and 14A and multipliers 12B and 14B. As shown in FIG. 3, the integrators 12A and 14A integrate the input pulses of the synchronizing signals H and V of FIG. 11A to obtain the sawtooth signals S ₁ and S having the waveforms of FIG. Output ₂ The sawtooth signals S ₁ and S ₂ have a waveform that swings in the positive and negative directions by the same width with 0 V as the center.
Multiplier 12B, in 14B, they sawtooth signal S _1, coefficient S ₂ K _1, K ₂ is multiplied by the modulated wave signal HC having a polarity and amplitude values shown in shown in FIG. 3 (c) or (d) , V
C is output. (C) is a waveform when the coefficients K ₁ and K ₂ are positive, and (c) is a waveform when the coefficients K ₁ and K ₂ are negative.

The operation capable of correcting the rotation distortion by the embodiment having the above-mentioned configuration will be described below.

First, an example in which rotation distortion occurs will be described with reference to FIGS. As shown in FIG. 4, the display screen section of the CRT display device includes a CRT 2 and a CRT 2.
It is composed of a frame 31 to which the RT2 is attached and an outer frame of a cabinet called a bezel 32 attached to the front surface of the CRT2. In general, the display area (raster area) 33 has a bezel 3 as shown in FIG.
The periods of the horizontal synchronizing signal H and the vertical synchronizing signal V are set so that the period falls within the area inside the second frame. This is because when the display area 33 is set to fill the frame of the bezel 32, the size and position of the display area 33 change due to the drift of the deflection current caused by changes in the ambient temperature and the like, and the peripheral portion is hidden by the bezel 32. This is because there is a risk that it will end up. Further, in order to display a fine figure or drawing, it is necessary to set the size of the display area in advance.

By the way, if the mounting position of the bezel 32 is displaced with respect to the CRT 2, the position of the display area 33 relative to the frame of the bezel 32 is relatively displaced, so that the peripheral portion of the display area 33 is hidden by the bezel 32. It causes a sense of discomfort, such as looseness and difficulty in viewing the screen. If the positional deviation is only in the horizontal or vertical direction, it can be adjusted and corrected by the vertical centering circuit incorporated in the horizontal centering circuit 13 and the vertical deflection circuit 15 described above. However, as shown in FIG. 6, the bezel 32 is attached in a relationship in which the display area 33 is rotated about the screen center O by an angle x as shown by a dotted line with respect to an ideal position shown by a solid line. May be That is, when the mounting position of the bezel 32 is mounted at a position rotated by the angle -x with respect to the reference horizontal axis X-X and the reference vertical axis Y-Y of the display area 33, the same state as the rotation distortion. It becomes.

Rotational distortion also occurs due to the deviation of the mounting angle of the deflection yoke 4 of the CRT 2. That is, when the deflection yoke 4 is attached to the tube surface 5 of the CRT 2 while rotating around the screen center, the deflection direction of the electron beam rotates accordingly. Again,
As shown in FIG. 6, the display area 33 is displayed at the position of the dotted line rotated around the screen center O. In order to remove such rotation distortion, the mounting angle of the deflection yoke 4 may be adjusted, but it is not easy because it is performed in the energized state and there is a risk of electric shock.

The operation of removing such rotation distortion by the embodiment shown in FIGS. 1 and 2 will be described with reference to FIG.
This will be described with reference to the operation waveform diagrams of FIGS. 8B and 8A and 8B. In FIG. 7, the horizontal axis of the display area is the reference horizontal axis X-.
FIG. 7 is a diagram for explaining an operation of correcting a rotation distortion that is symmetrically rotated with respect to X. 7A is a waveform diagram of each part for explaining the modulation operation of the vertical deflection current VD, and FIG. 7B is a diagram showing a display state of the display area 33.
As shown in the figure, this is a case of a parallelogram distortion in which a display area 33 having a vertical length of 270 mm and a horizontal length of 360 mm is vertically distorted and a displacement of 3 mm occurs at the horizontal end position. This distortion can be removed by modulating the vertical deflection current VD.

That is, as shown in FIGS. 7A and 7A, when the vertical synchronizing signal V consisting of a pulse signal having a constant cycle (for example, a cycle of 20 ms to 10 ms) is input to the vertical deflection circuit 15, vertical deflection is performed. The circuit 15 outputs the deflection current VD ₀ having the sawtooth-shaped reference waveform shown in (b) according to the vertical synchronizing signal V. Further, the vertical deflection modulation wave generation circuit 14
A constant period as shown in (c) (for example, a period of 65 μs
When the horizontal synchronizing signal H composed of a pulse signal of 10 μs) is input, the sawtooth modulation wave signal VC shown in (d) is output. The amplitude value of the modulated wave signal VC is, for example, 0.02 in peak-to-peak, corresponding to the inclination of 3 mm.
Adjusted to App. This adjustment is performed by operating the sliding resistance 17 of the adjusting circuit 16 and setting the magnitude of the coefficient K ₂ . The polarity of the modulated wave signal VC in the case of FIG. 7 is adjusted to the polarity shown in (d) by setting the coefficient K ₂ to be positive. When the inclination of the horizontal axis is in the opposite direction, the coefficient K ₂ may be set to a negative value to invert the polarity of the waveform shown in (d).

Modulated wave signal VC thus generated
Is input to the vertical deflection circuit 15, the deflection current VD _{0 of the} reference waveform is modulated according to the modulation wave signal, and is modulated into a waveform in which the modulation wave as shown in (e) is superimposed. As a result, the electron beam is scanned by the superimposed saw-tooth wave of a short cycle for each horizontal scanning line while being swung with a constant width in the vertical direction. Looking at this phenomenon from the viewpoint of the horizontal scanning of the electron beam, each horizontal scanning line corresponds to the reference horizontal axis as shown by the arrow in FIG. 7B by the width in which the electron beam is vertically swung. Rotate with respect to parallelogram distortion to be corrected. The direction and angle of the rotation depend on the polarity and amplitude value of the superimposed modulated wave. Therefore, the polarity and amplitude value of the superimposed modulated wave current are displayed in the display area 33 with respect to the reference horizontal axis.
The tilt of the horizontal axis of the display area 33 can be corrected by adjusting K ₂ in accordance with the direction and size of the tilt of the horizontal axis of.

FIG. 8 is a diagram for explaining the operation of correcting the parallelogram distortion in which the vertical axis of the display area 33 is inclined with respect to the reference vertical axis Y-Y. FIG. 8A is a waveform diagram of each part for explaining the modulation operation of the horizontal deflection current HD, and FIG.
(B) is a diagram showing a display state of the display area 33. As shown in the figure, this is a case of a parallelogram distortion in which a display area 33 having a length of 270 mm and a width of 360 mm is distorted in the horizontal direction and a displacement of 3 mm is generated at the vertical end position. For this distortion,
It can be removed by modulating the horizontal deflection current HD.

That is, as shown in FIGS. 8A and 8A, when the horizontal synchronizing signal H, which is a pulse signal having a constant period (for example, a period of 65 μs to 10 μs), is input to the horizontal deflection circuit 11, horizontal deflection is performed. The circuit 11 outputs a deflection current HS ₀ having a sawtooth reference waveform shown in (b) according to the horizontal synchronizing signal H. In addition, the horizontal deflection modulation wave generation circuit 12
A constant cycle as shown in (c) (for example, cycle 20 ms-
When the vertical synchronizing signal V composed of a pulse signal of 10 ms) is input, the sawtooth-shaped modulated wave signal HC shown in (d) is output. The amplitude value of the modulated wave signal HC corresponds to the above-mentioned inclination of 3 mm and is, for example, 0.1 A at peak to peak.
adjusted to pp. This adjustment is made by operating the sliding resistance 17 of the adjusting circuit 16 to set the magnitude of the coefficient K ₁ . The polarity of the modulated wave signal HC in the case of FIG. 8 is adjusted to the polarity shown in (d) by setting the coefficient K ₁ to be positive. If the vertical axis tilts in the opposite direction,
The polarity of the waveform shown in (d) may be inverted by setting the coefficient K ₁ to a negative value.

Modulated wave signal HC thus generated
Is input to the horizontal centering circuit 13, the deflection current HS _{0 of the} reference waveform is modulated according to the modulated wave signal HC, and is modulated into a waveform in which a modulated wave as shown in (e) is superimposed. As a result, the electron beam is displaced in the horizontal direction by the superimposed sawtooth wave having a long cycle, in which all of the plurality of horizontal scanning lines are sequentially arranged according to the amplitude of the modulated wave. As a result, the vertical axis of the display area 33 is rotated as shown by the arrow in FIG. The direction and angle of the rotation depend on the polarity and amplitude value of the superimposed modulated wave. Therefore, the polarity and amplitude value of the modulated wave current to be superimposed are displayed on the display area 33 with respect to the reference vertical axis.
The tilt of the vertical axis of the display area 33 can be corrected by adjusting K ₁ in accordance with the direction and size of the tilt of the vertical axis of.

By combining the above operations in vector, it is possible to effectively eliminate the rotation distortion in which the entire display area 33 rotates around the screen center O.

As described above, by operating the sliding resistance 20 according to the magnitude of the rotation strain and the rotating direction, the rotation strain can be easily removed even after the image display device is assembled.

Further, according to the present invention, it is possible to eliminate the rotation distortion due to the influence of the magnetic field such as the earth magnetism. Rotational distortion due to this magnetic field will be described with reference to FIGS. 9 and 10A and 10B. CRT2
Is for displaying an image by scanning an electron beam with a magnetic field generated by the deflection yoke 4. Therefore, it is easily affected by the external magnetic field. Generally, the external magnetic field that is easily affected is geomagnetism. As shown in FIG. 9, the electron beam emitted from the electron gun of the CRT 2 toward the tube surface 5 has velocity vectors V ₁ , V ₂ , V ₃ , and V ₄ at the position of the display area 33 on the tube surface 5. .. On the other hand, for example, when a magnetic field B in a direction perpendicular to the screen acts as shown in FIGS. 10A and 10B, the electron beam has velocity vectors V ₁ , V ₂ , V ₃ and V ₄ . A component orthogonal to the magnetic field B in the magnetic field B is deflected in a direction according to the strength and direction of the magnetic field B. Then, the entire display is rotated in the direction of the arrow in the figure in accordance with the deflection forces f ₁ , f ₂ , f ₃ , and f ₄ .

In consideration of such magnetic rotation distortion, generally, at the time of shipping of a CRT image display device, adjustment is made so as to remove the rotation distortion under the geomagnetic conditions of the location. However, if the direction in which the CRT image display device is installed or the strength of the earth's magnetism is different from the adjusted location, rotation distortion will occur. According to the present invention, such distortion can be easily dealt with even after installation.

Here, modified examples of the adjusting circuit 16 are shown in FIGS. The adjustment circuit 16 'shown in FIG. 11 is provided with separate adjustment circuits for horizontal deflection modulation and vertical deflection modulation. Further, in the adjustment circuit 16 ″ of FIG. 12, the resistors 19 and 20 of the adjustment circuit 16 of FIG.
9 ', 20', and switches S ₁ and S ₂ are further inserted in these resistance circuits. According to these embodiments, the parallelogram distortion of FIG. 7B or 8B can be separately corrected and removed.

[0045]

As described above, according to the present invention,
The rotation distortion of the CRT screen can be removed with a simple configuration without using the rotation distortion correction coil.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an embodiment of an image display device according to the present invention.

FIG. 2 is a block configuration diagram of an embodiment of a deflection circuit of the present invention.

FIG. 3 is a signal waveform diagram of each part of the horizontal / vertical deflection modulation wave generation circuit.

FIG. 4 is an exploded perspective view showing a structure of a CRT display screen section.

FIG. 5 is an explanatory diagram showing a relationship between a bezel and a display area of the image display device.

FIG. 6 is a diagram illustrating a relationship between an ideal display position of a display area and a state when rotation distortion is applied.

FIG. 7 is a diagram for explaining a rotation distortion correction operation in which the horizontal axis of the display area is inclined with respect to the reference horizontal axis, and FIG. 7A is a waveform of each part for explaining the vertical deflection current modulation operation. FIG. 1B is a diagram showing a display state of the display area.

FIG. 8 is a diagram for explaining a correction operation of a rotation distortion in which a vertical axis of a display area is inclined with respect to a reference vertical axis, and FIG. 8A is a waveform diagram of each part for explaining a horizontal deflection current modulation operation. FIG. 3B is a diagram showing a display state of the display area.

FIG. 9 is an explanatory diagram showing a relationship between an electron beam emitted from a neck portion of a CRT toward a tube surface and a velocity vector at an end portion of a display area of the tube surface.

10A and 10B are explanatory diagrams showing the influence of the geomagnetism on the screen of the CRT.

FIG. 11 is a configuration diagram showing a modified example of the adjustment circuit according to the present invention.

FIG. 12 is a configuration diagram showing another modified example of the adjustment circuit according to the present invention.

[Explanation of symbols]

 1 image amplification circuit 2 CRT 4 deflection yoke 5 CRT tube surface 6 horizontal deflection coil 7 vertical deflection coil 10 high voltage generation circuit 11 horizontal deflection circuit 12 horizontal deflection modulated wave generation circuit 12A integrator 12B multiplier 13 horizontal centering circuit 14 vertical deflection modulation Wave generation circuit 14A Integrator 14B Multiplier 15 Vertical deflection circuit 16 Adjustment circuit 17 Sliding resistance 18 Amplification circuit 19,20 Output resistance 32 Bezel 33 Display area

Claims (20)

[Claims] 1. A sawtooth-shaped vertical deflection current flowing through a vertical deflection coil of a CRT is superimposed with a sawtooth current in synchronization with a horizontal synchronizing signal, and the polarity and amplitude value of the sawtooth current are displayed on a reference horizontal axis. CRT screen rotation distortion correction method for adjusting the horizontal axis tilt of a display image by adjusting the horizontal axis tilt direction and size. 2. A sawtooth-shaped horizontal deflection current flowing in a horizontal deflection coil of a CRT is superimposed with a sawtooth current in synchronization with a vertical synchronizing signal, and the polarity and amplitude value of the sawtooth current are displayed on a reference vertical axis. A rotation distortion correction method for a CRT image, which adjusts the vertical axis tilt of a display image by adjusting the vertical axis tilt direction and size. 3. A sawtooth-shaped vertical deflection current flowing through a CRT vertical deflection coil, superimposed on a sawtooth-shaped vertical deflection current in synchronization with a horizontal synchronizing signal, and flowing through a CRT horizontal deflection coil. A second sawtooth current is superimposed on the current in synchronization with the vertical synchronizing signal, and the polarities and amplitudes of the first and second sawtooth currents are determined according to the direction and magnitude of the rotation distortion of the display image with respect to the reference position. A rotation distortion correction method for a CRT screen that adjusts the value to correct the rotation distortion of the displayed image. 4. The method according to claim 1, 2, or 3,
A rotation distortion correction method for a CRT screen, characterized in that the cycle of the sawtooth current superimposed on the vertical or horizontal deflection current is matched with the cycle of a horizontal or vertical synchronizing signal to be synchronized. 5. A horizontal deflection circuit for supplying a sawtooth horizontal deflection current to a horizontal deflection coil of a CRT in synchronism with a horizontal synchronization signal, and a sawtooth vertical deflection to a vertical deflection coil of a CRT in synchronization with a vertical synchronization signal. A vertical deflection circuit that supplies a current, a modulation wave generation circuit that generates a sawtooth modulation wave signal that is synchronized with a horizontal synchronization signal, and an adjustment circuit that variably sets the polarity and amplitude value of this modulation wave signal are provided. And a CRT configured to modulate the vertical deflection current with the modulation wave signal.
Deflection circuit. 6. A horizontal deflection circuit for supplying a sawtooth-shaped horizontal deflection current to a horizontal deflection coil of a CRT in synchronization with a horizontal synchronization signal, and a sawtooth-shaped vertical deflection to a vertical deflection coil of a CRT in synchronization with a vertical synchronization signal. A vertical deflection circuit that supplies a current, a modulation wave generation circuit that generates a sawtooth modulation wave signal that is synchronized with a vertical synchronization signal, and an adjustment circuit that variably sets the polarity and amplitude value of the modulation wave signal are provided. And a CRT adapted to modulate the horizontal deflection current with the modulating wave signal.
Deflection circuit. 7. The horizontal deflection circuit according to claim 6, comprising a horizontal centering circuit for controlling a grounding side potential of the deflection coil to adjust a horizontal center of a display screen, and a control output of the horizontal centering circuit. A deflection circuit for a CRT, characterized in that the horizontal deflection current is modulated by modulating the modulated wave signal. 8. A horizontal deflection circuit for supplying a sawtooth horizontal deflection current to a horizontal deflection coil of a CRT in synchronization with a horizontal synchronization signal, and a sawtooth vertical deflection to a vertical deflection coil of a CRT in synchronization with a vertical synchronization signal. A vertical deflection circuit that supplies a current, a modulation wave generation circuit that generates a sawtooth-shaped first modulation wave signal that is synchronized with a horizontal synchronization signal, and a polarity and an amplitude value of the first modulation wave signal that are variably set. A first adjusting circuit, a second modulating wave generating circuit for generating a sawtooth-shaped second modulating wave signal synchronized with the vertical synchronizing signal, and a polarity and an amplitude value of the second modulating wave signal are variably set. And a second adjusting circuit for
A deflection circuit of a CRT configured to modulate the vertical deflection current with the first modulation wave signal and modulate the horizontal deflection current with the second modulation wave signal. 9. A horizontal deflection circuit for supplying a sawtooth horizontal deflection current to a horizontal deflection coil of a CRT in synchronization with a horizontal synchronization signal, and a vertical sawtooth deflection for a vertical deflection coil of a CRT in synchronization with a vertical synchronization signal. A vertical deflection circuit that supplies a current, a first modulation wave generation circuit that generates a sawtooth-shaped first modulation wave signal that is synchronized with the horizontal synchronization signal, and a sawtooth-shaped second modulation wave circuit that is synchronized with the vertical synchronization signal. A second modulation wave generation circuit for generating a modulation wave signal; and an adjustment circuit for variably setting the polarities and amplitude values of the first and second modulation wave signals, respectively. The vertical deflection current and the horizontal deflection current are respectively modulated by a modulation wave signal C
RT deflection circuit. 10. The horizontal deflection circuit according to claim 9, further comprising a horizontal centering circuit that controls a ground side potential of the deflection coil to adjust a horizontal center of the display screen.
A deflection circuit of a CRT, characterized in that the control output of the horizontal centering circuit is modulated by the second modulated wave signal to modulate the horizontal deflection current. 11. The sawtooth wave generating circuit for generating a sawtooth wave synchronized with a horizontal / vertical synchronizing signal, and each of the sawtooth wave generating circuits according to claim 8. And a multiplier that multiplies the output of the multiplier by a coefficient, and the adjusting circuit is a circuit that variably sets the polarity and size of the coefficient of the multiplier. 12. The coefficient generating circuit according to claim 11, wherein the coefficient generating circuit generates a variable level coefficient signal having polarity, and the coefficient signal is supplied to the multiplier via the switch and the adjusting resistor, respectively. And a coefficient distribution circuit for outputting as a CRT.
Deflection circuit. 13. The deflection circuit for a CRT according to claim 12, wherein the adjustment resistor is a variable resistor. 14. The CRT according to any one of claims 5 to 13, wherein each of the modulated wave generation circuits generates the modulated signal in synchronization with a cycle of a horizontal or vertical synchronizing signal for synchronizing the cycle of each modulated signal. Deflection circuit. 15. A video amplifier circuit for amplifying an image signal,
C having an electron gun to which the output of this video amplifier circuit is input
RT, a horizontal deflection coil and a vertical deflection coil for scanning the electron beam of the CRT, a horizontal deflection circuit that supplies a sawtooth horizontal deflection current to the horizontal deflection coil in synchronization with a horizontal synchronization signal, and a vertical synchronization A vertical deflection circuit that supplies a sawtooth-shaped vertical deflection current to the vertical deflection coil in synchronization with a signal, and a first modulation wave generation circuit that generates a sawtooth-shaped first modulation wave signal synchronized with a horizontal synchronization signal. And a second modulation wave generation circuit for generating a sawtooth-shaped second modulation wave signal synchronized with the vertical synchronization signal, and the polarities and amplitude values of the first and second modulation wave signals are variably set. An image display device comprising an adjusting circuit, wherein the vertical deflection current and the horizontal deflection current are respectively modulated by the first and second modulated wave signals. 16. The horizontal deflection circuit according to claim 15, comprising a horizontal centering circuit for adjusting a grounding side potential of the deflection coil to adjust a horizontal center of a display screen, and a control output of the horizontal centering circuit. An image display device characterized by modulating the horizontal deflection current by modulating with the second modulated wave signal. 17. The method according to claim 16, wherein the first and second
The modulated wave generation circuit of includes a sawtooth wave generation circuit that generates a sawtooth wave synchronized with the horizontal and vertical synchronization signals, and a multiplier that multiplies the output of each sawtooth wave generation circuit by a coefficient,
The image display device, wherein the adjustment circuit is a circuit that variably sets the polarity and magnitude of the coefficient of the multiplier. 18. The coefficient adjusting circuit according to claim 17, wherein the adjusting circuit generates a variable-level coefficient signal having a polarity, and the coefficient signal is supplied to the multiplier via a switch and an adjusting resistor, respectively. An image display device comprising: a coefficient distribution circuit for outputting as. 19. The image display device according to claim 18, wherein the adjustment resistor is a variable resistor. 20. The image display device according to claim 15, wherein the modulated wave generation circuit generates the modulated signals in synchronization with a cycle of a horizontal or vertical synchronizing signal for synchronizing the cycle of each modulated signal.