JP2001224038A - Crt display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of a conventional CRT display device that causes mis-convergence due to the effect of the earth magnetism or the like. SOLUTION: In the CRT display device having a video circuit receiving a video signal, a CRT that performs displays on the basis of an output video signal of the video circuit, a deflection circuit that drives deflection of the CRT on the basis of horizontal synchronizing signal and vertical synchronizing signal pulses inputted with the video signal, a rotation circuit that corrects the rotation of the raster displayed on the CRT, an earth magnetism detection circuit that detects earth magnetism and a CPU that controls the rotation circuit and the deflection circuit, the CPU controls the rotation circuit and the deflection circuit on the basis of an output of the earth magnetism detection circuit so as to adjust a rotation correction value and a vertical movement correction quantity of the raster displayed on the CRT.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device used for a computer terminal or the like, and more particularly to a display device for displaying a computer video signal such as a personal computer or a work station. The present invention relates to a CRT display device provided.

[0002]

2. Description of the Related Art In recent years, a display device using a CRT has been desired to improve display performance by improving display resolution of a computer video signal. With the improvement in resolution, the dot pitch of CRTs has also become finer. For example, in the case of a 21-inch CRT display, the pitch interval is 0.25
mm, which tends to be finer. The convergence performance requires that the R, G, and B electron beams from the electron gun of the CRT correctly irradiate each of the RGB fluorescent pairs of the target pixel.
Due to the overall performance of T and the deflection yoke, it is extremely difficult to eliminate misconvergence (a state in which convergence performance cannot be obtained). On the other hand, a pixel fixed display such as a liquid crystal display does not cause misconvergence due to its device characteristics. Under the circumstances described above, further improvement in convergence performance, particularly for CRT displays, is desired.

Here, the factors causing misconvergence are firstly the influence of the external magnetic field of the CRT display, mainly due to geomagnetism, and secondly, the CR.
Some of them depend on the internal magnetic field characteristics of T and a deflection yoke (hereinafter, DY). In the second factor, since the misconvergence characteristic is unique to the display device, the correction data corresponding to the misconvergence correction amount is stored in an internal memory, and the convergence correction is digitally performed using the correction data. Some do. In such a device, correction data corresponding to each position on the CRT screen is stored in a convergence correction memory, and the memory data is read out in association with the CRT screen based on an input synchronization signal, and D is read. After the / A conversion process, the convergence correction yoke (CY) mounted on the CRT tube axis is driven via the current amplifier. As such a conventional example, a large number of applications such as Japanese Patent Application Laid-Open No. H10-210488 have been found.

Japanese Patent Application Laid-Open No. Hei 7-203469 is disclosed as a conventional example corresponding to the first geomagnetic effect. FIG. 11 shows a configuration diagram of this conventional example. In the figure, 121 indicates the entire CRT, 121a is an electron gun inside the CRT, 121b is a front panel of the CRT, 121c
Is a funnel part of a CRT, 122 is a magnetic detecting element, 12
Reference numeral 3 denotes a current supply circuit. FIGS. 12 and 13 show the influence of the geomagnetism on the electron beam emitted from the electron gun 121a. In FIG. 12, C
The electron beam emitted by the terrestrial magnetism in the tube axis direction of the RT 121 rotates, and the electron beam passing through the shadow mask for color selection of the electron beam inside the CRT 121 deviates from the fluorescent pair of the target color and has a different color. Mislanding occurs because the phosphor is also struck. In this case, FIG.
As shown in (2), since the electron beam only irradiates a part of the fluorescent pair (the gray part in the figure), partial light emission occurs. As a result, color purity deteriorates in the peripheral portion of the CRT tube surface. On the other hand, in FIG. 13, each electron beam of RGB is affected by the change in the magnetic field in the tube axis direction of the CRT 121, but the influence is different depending on the arrangement difference of each electron beam of RGB. When the green beam is used as a reference as in 13, the red beam R and the blue beam B are shifted in the vertical direction. Further, due to the influence of the magnetic field in the tube axis direction, the shape of the raster scanned by the electron beam is different from that of the raster in the zero magnetic field state where no magnetic field exists.
Rotate as shown in (a) or (b). In order to correct the above, in the conventional example of FIG. 11, the polarity and strength of the magnetic field in the tube axis direction of the CRT 121 (the direction connecting the CRT tube surface and the electron gun) detected by the magnetic detection element 122 are detected. A corresponding electric magnetic field detection signal is output. Current supply circuit 12
3 supplies a current that cancels out the influence of an external magnetic field to each of the compensation coils 124, 125, and 126 according to the magnetic field detection signal from the magnetic detection element 122. Compensation coil 12
Reference numeral 4 is wound near the panel section 121b, and generates a magnetic field for compensating for mislanding by a current supplied from the current supply circuit 123. Similarly, compensation coil 125 is wound around funnel 121c to generate a magnetic field that compensates for raster rotation, and compensation coil 126 is
A magnetic field for compensating for the vertical displacement of the red and blue electron beams is provided at the neck of the electron beam. In this conventional example, the internal magnetic shield provided inside the CRT prevents adverse effects due to external magnetic fields other than in the tube axis direction.

[0005]

In the above prior art, C
Only the case of correcting the influence of the terrestrial magnetism in the tube axis direction of the RT and the correction of the convergence variation caused by the influence of the terrestrial magnetism have been individually studied. However, the prior art was insufficient for actually improving the convergence performance and reducing the misconvergence as much as possible.

That is, even in the case of the influence of terrestrial magnetism, the direction in which the CRT display device is installed varies depending on the user, and the CRT display device is installed in all directions of east, west, north and south. Further, in the CRT, it is difficult to complete the effect of the internal magnetic shield for preventing an adverse effect due to an external magnetic field other than in the tube axis direction, and the CRT is also affected in directions other than the tube axis direction. Therefore, as in the first known example, the vertical movement of the screen raster due to the magnetic field in the tube surface direction cannot be controlled by the control only in the CRT tube axis direction. On the other hand, in the second known example, the convergence correction device that corrects the influence of the terrestrial magnetism only operates to correct the variation of the beam current due to the terrestrial magnetism, but cannot correct the influence of the raster movement. In particular, the effect of the raster position shift due to the terrestrial magnetism is greater than the effect of the above-described beam current variation. Although it is possible to handle the vertical movement and rotation of the raster by correcting the vertical position adjustment function of the deflection circuit and the adjustment function of the rotation circuit by the user of the display device, the general user is In most cases, the above knowledge is not possessed, and slight deviations are permitted. Therefore, the display device is used in a state where the convergence performance is deteriorated. On the other hand, even in the case of a user who is aware of the above principle, in order to obtain the optimum position, the screen position is adjusted while confirming the convergence performance on the screen one by one, which is troublesome. .

Further, the convergence performance is affected not only by the geomagnetic field but also by a signal delay characteristic and a temperature characteristic of the circuit system since a drive circuit system for current-driving the convergence correction yoke is generally an analog circuit. . Current display devices operate in a wide range of horizontal deflection frequencies from about 30 kHz to about 120 kHz. For this reason, as the deflection frequency becomes higher, the influence of the phase lag of the convergence correction circuit appears as shown in FIG. 9, so that the convergence correction waveform created in the digital section is distorted in the analog section as in the conventional example, and Correction effect cannot be expected.

Further, a DC drift occurs due to the temperature characteristics of the convergence correction yoke driving amplifier of the convergence correction circuit. Due to this effect, if the internal temperature of the display set does not reach the predetermined temperature assumed at the time of manufacturing the set, the DC current value flowing through the convergence correction yoke changes and the static convergence performance of the set deteriorates. The static convergence performance deterioration causes a convergence shift in the entire screen. Therefore, in order to obtain the optimum convergence performance, the user of the display device needs to wait for the set internal temperature to reach a predetermined value.

[0009] As described above, in the prior art, the convergence performance cannot be improved or the usability is poor.
The present invention solves the above-described problems, and realizes the best convergence almost automatically under any use environment of the display device, without bothering the user of the display device regardless of the installation orientation of the display device. To provide a display device having a convergence correction function.

[0010]

In order to solve the above-mentioned problems, a display device according to the present invention comprises a video circuit to which a video signal is input, a CRT for displaying based on an output video signal of the video circuit, The CRT based on horizontal and vertical synchronization pulses input together with a video signal
A deflecting circuit for deflecting the CRT, a rotation circuit for correcting rotation of a raster displayed on the CRT, a terrestrial magnetism detecting circuit for detecting terrestrial magnetism, a convergence correcting circuit for performing convergence correction for the CRT, and the convergence correcting circuit. In a display device having the rotation circuit and a CPU for controlling the deflection circuit, the C device is controlled based on an output of the terrestrial magnetism detection circuit.
The PU controls the rotation circuit and the deflection circuit to adjust the rotation correction amount and the vertical movement correction amount of the raster displayed on the CRT to the reference raster position.

Further, the display device according to the present invention comprises:
A video circuit to which a video signal is input; a CRT for displaying based on an output video signal of the video circuit; a deflection circuit for deflecting and driving the CRT based on horizontal and vertical synchronization pulses input together with the video signal; The CRT
A convergence correction circuit that performs convergence correction, a convergence correction yoke driven by an output current from the convergence correction circuit, a temperature detection circuit that detects an internal temperature of the convergence correction circuit,
A display device having the convergence correction circuit and a CPU for controlling the deflection circuit;
Controls the convergence correction circuit based on the output of the temperature detection circuit and adjusts the output DC current of the convergence correction circuit.

Further, the display device according to the present invention comprises:
A video circuit to which a video signal is input; a CRT for displaying based on an output video signal of the video circuit; a deflection circuit for deflecting and driving the CRT based on horizontal and vertical synchronization pulses input together with the video signal; The CRT
A convergence correction circuit that performs the convergence correction, a convergence correction yoke driven by an output current from the convergence correction circuit, and a CPU that controls the convergence correction circuit and the deflection circuit. The circuit includes a signal processing unit that generates a convergence correction signal based on the control of the CPU, a convergence amplifier unit that drives the convergence correction yoke with a current from the convergence correction signal, and converts a current flowing through the convergence correction yoke into a voltage waveform. And a compensation signal generator for compensating for a phase delay of the convergence amplifier based on the converted voltage waveform, and the signal processor generates a convergence correction signal using the compensation signal. It is intended.

[0013]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a display device according to an embodiment of the present invention. In the figure, 1 is a video circuit, 2 is a deflection circuit, 3 is a CPU,
Is a convergence correction circuit, 5 is a rotation circuit,
6 is a geomagnetism detection circuit, 7 is an A / D conversion circuit, and 8 is CR
T and 9 are deflection yokes, 10 is a convergence correction yoke (CY), and 11 is a rotation coil.

In FIG. 1, a video circuit 1, a deflection circuit 2, a CP
A portion including the U3, the rotation circuit 5, the CRT 8, the deflection yoke 9, and the rotation coil 11 is substantially the same as the configuration of a general CRT display device. In the operation, the CPU 3 detects and recognizes the period, frequency, and polarity of the input horizontal and vertical synchronization signals, and generates control information for the video circuit 1 and the deflection circuit 2 that matches the detected information. The CPU 3 transmits the control information to the video circuit 1 or the deflection circuit 2 in the form of digital data as control data, or converts the data into an analog DC voltage by a D / A conversion circuit (not shown), and Supply to circuit 2. The video circuit 1 and the deflection circuit 2 correspond to the CPU 3
The video signal is displayed on the CRT 8 by adjusting the signal amplitude, the DC level, the raster size, the raster position, or the position of the video signal based on the control of the video signal.

The rotation circuit 5 includes a D / A conversion circuit for converting the rotation control data Rot from the CPU 3 into a DC voltage, and a current amplifier for driving the rotation coil 11 based on the output of the D / A conversion circuit. Therefore, the rotation coil 11 is driven by the DC current output from the rotation circuit 5, and C
The rotation of the raster displayed on RT8 is corrected.

Next, the operation of the convergence correction circuit 4 will be described with reference to the detailed configuration diagram of the convergence correction circuit of FIG. 2, reference numeral 201 denotes a signal processing circuit (hereinafter, DSP); 202, a D / A conversion circuit; 203, a convergence correction yoke drive amplifier (hereinafter, CY amplifier); 204, a current-voltage conversion resistor; It is the same as FIG.

First, the DSP 201 sends basic information for convergence correction sent from the CPU 3, for example, adjustment point data indicating the basic correction pattern itself, and mathematical data of the basic correction pattern in the form of a mathematical expression. Based on coefficient data and the like, an internal calculation is performed using the input horizontal synchronization signal and vertical synchronization signal as a calculation reference. At this time, the DSP 201 sends C
Also receives the raster size and raster position information displayed on the RT8, and displays the raster and DS displayed on the CRT8.
P201 calculation is associated with convergence correction data output. The D / A conversion circuit 202
The convergence correction data output from P201 is converted into an analog voltage.
CY9 is current-driven based on the output of the A conversion circuit 202. The current 9 flowing through the CY 9 is controlled by the current feedback type feedback control in which the voltage is converted again by the resistor 204.
Y amplifier 203 performs a correction operation so as to follow the input correction voltage waveform.

Next, the raster correction control displayed on the CRT 8 by the terrestrial magnetism detection circuit 6, A / D conversion circuit 7, and CPU 3 in FIG. 1 will be described.

FIG. 3 is a diagram showing the influence of geomagnetism on a raster displayed on the CRT 8. In the figure, the outermost square portion indicates an image frame existing on the outer periphery of the CRT 8, the dotted square portion indicates a reference raster position in a zero magnetic field state where geomagnetism does not exist, and the solid line indicates a raster when geomagnetism exists. It is a state of. When the tube surface of the CRT 8 is facing south as shown in FIG. 3 (a), the raster rotates clockwise, and when facing north as shown in FIG. 3 (b), the raster rotates counterclockwise. Become. Further, in the case of the westward direction in FIG. 3C, the raster moves upward and has a trapezoidal shape with an upward opening, and in the eastward direction, as shown in FIG. Show the shape. At this time, the terrestrial magnetism detection circuit 6 detects terrestrial magnetism in accordance with the direction of the tube surface of the CRT 8, and the output is as shown in FIG.
Here, the geomagnetism detection circuit 6 includes a first element for detecting a magnetic field (x-axis) in the tube axis direction for detecting geomagnetism and a second element for detecting a magnetic field (y-axis) in a direction horizontal to the tube axis. It consists of. Each element detects the geomagnetism in each direction and outputs x data and y data. For example, a Hall element, a magnetoresistive element, a magnetic impedance element, a flux gate sensor, and the like can be used for each element. The present embodiment is an example in which a flux gate sensor is used. The direction of the tube surface of the display device can be detected from the X and Y axis outputs of this sensor.

The CPU 3 takes in the output of the terrestrial magnetism detection circuit 6 as digital data via the A / D conversion circuit 7 and detects the direction of the display device. Further, the CPU 3 performs the operation shown in FIG.
And the relationship between the amount of rotation of the raster and the direction, and FIG.
From the relationship between the vertical movement amount and the direction of the raster as described above, the respective correction amounts of the correction data Rot for performing the rotation correction of the raster and the correction data Vposi for performing the vertical position correction are calculated, and the rotation circuit and the deflection circuit are calculated. Send to 2.

The detection of the direction by the CPU 3 can be obtained by an arithmetic expression from, for example, X-axis and Y-axis output data. Alternatively, the direction can be stored in a memory inside the CPU 3 in the form of a look-up table. You can also ask.

For example, when calculating from an arithmetic expression, the above X
Axis output data value X, Y axis output data value Y, azimuth angle Dx,
If Dy

[0024]

X = a * sin (Dx) Equation 1 Y = b * cos (Dy) Equation 2 If the above equation is developed for the angle D,

[0025]

Dx = sin ~ ¹ (X / a) ··· Equation 3 Dy = cos ~ ¹ (Y / b) ··· Equation 4 and the solution of the above Equations 3 and 4 Dx = Dy Is the azimuth angle to be obtained. From the above, the angle D can be obtained. Here, a and b are coefficients.

Similarly, the correction of the raster rotation correction amount and the vertical movement amount can be performed by an arithmetic expression method or a reference expression method.

FIG. 5 shows a processing procedure of the CPU 3 when correcting raster movement due to terrestrial magnetism. In processing 1, geomagnetic detection data from the A / D conversion circuit 7 is obtained,
In process 2, the difference from the previous geomagnetic detection data is checked. If there is a difference, it is determined that the installation location of the display device has been changed or the orientation has been changed, and the process proceeds to the next process 3. If there is no change, the process returns to processing 1. At this time, the geomagnetism detection data may be obtained at predetermined time intervals or at predetermined vertical intervals, and another process may be performed during that time. Next, in process 3, the direction in which the display device is facing is obtained from the acquired data. The calculation method is as described above. In processing 4, the raster rotation correction amount Rot and the raster vertical correction amount Vp are calculated from the direction data calculated in processing 3.
Calculate osiMM. As described above, the calculation method is performed using an arithmetic expression or a lookup table. In process 5, the calculation of the raster vertical movement amount data Vposi is actually performed. The vertical movement amount data is a vertical movement correction amount corresponding to a difference in vertical display timing (a video period, a front porch period, a back porch period, a synchronization signal period, etc.) of a video signal input to the display device in FIG. It is obtained by adding VposiDSP and the above VposiMM. In process 6, the obtained raster rotation correction data,
The vertical movement correction data is set in the rotation circuit and the deflection circuit, respectively, so that the influence of the raster movement due to the terrestrial magnetism can be corrected. In this way, the raster can always be displayed at a fixed position on the screen of the CRT 8 irrespective of the terrestrial magnetism. Therefore, the convergence correction circuit 4 does not need to control the raster by following the raster moved up and down by the terrestrial magnetism. What is necessary is just to operate so as to follow only the signal timing. Therefore, the internal processing of the DSP 201 in FIG. 2 can eliminate the influence of geomagnetism.

In the above-described example, the raster position at the zero magnetic field is processed as the reference state. However, for example, a case where the east is facing east may be processed as the raster position of the reference magnetic field. In this case, the north-south direction is the vertical movement of the raster, and the west direction is the rotation. In the above-mentioned geomagnetic detection, the case of the northern hemisphere was described as a two-axis detection, and the direction of the tube axis of the CRT 8 and a direction parallel to the tube surface were described. It can also be.
In this case, the added detection axis is in the vertical direction with respect to the tube surface, it is possible to detect the magnetic field in the southern hemisphere and the northern hemisphere, it is possible to perform geomagnetic detection anywhere on the earth, and it is more complete Automatic correction is possible.

Another embodiment of the present invention will be described with reference to the drawings.

FIG. 6 is a block diagram showing the configuration of a display device according to an embodiment of the present invention. The above-described embodiment according to the present invention corrects the influence of misconvergence due to terrestrial magnetism, while the present embodiment is different from the above-described embodiment in that it is an example in which the influence of misconvergence due to temperature is further corrected. In FIG. 6, 6
01 is a temperature detection circuit, and 602 is an A / D conversion circuit.
In addition, the same reference numerals are given to the same portions, and duplicate description will be omitted.

FIG. 7 shows the DC drift of the CY amplifier which is a component of the convergence correction circuit 4 of FIG. As shown in the figure, the DC current output from the CY amplifier changes depending on the heat generation of the circuit and the ambient temperature. Temperature detection circuit 60 of FIG.
1 is a temperature sensor installed near the CY amplifier,
A temperature change of the Y amplifier is detected. The temperature detection value is A / D
The conversion circuit 602 uses the CPU 3
To calculate the DC drift amount of the CY amplifier.
In the case of a drift curve as shown by the solid line in FIG. 7, the calculation is performed from a reverse polarity curve of a broken line that corrects the drift curve. This curve data is a function formula using the temperature detection data as a parameter,
Alternatively, it can be realized by having a reference table showing the temperature detection data versus the DC drift correction amount in the CPU 3. As described above, the CPU 3 sets the obtained drift correction amount in the signal processing circuit 201 in FIG. 2 so that the influence of the DC drift of the CY amplifier due to the temperature can be reduced.

Another embodiment of the present invention will be described with reference to the drawings.

FIG. 8 is a block diagram showing the configuration of the convergence correction circuit 4 of the display device according to an embodiment of the present invention. The above-described embodiment according to the present invention in FIG. 2 is an example realized by the DSP 201, the D / A conversion circuit 202, the CY amplifier 203, and the current-voltage conversion resistor 204, whereas the present embodiment performs processing in the DSP 201 in FIG. This embodiment is different from the above-described embodiment in that the embodiment is realized by adding a DSP 801, an A / D conversion circuit 803, a delay circuit 804, and a comparator 805 to which functions are added. Hereinafter, the operation will be described in detail with reference to FIG. 8 and FIG. In addition, the same reference numerals are given to the same portions, and duplicate description will be omitted.

FIG. 9 shows the CY amplifier 203 shown in FIGS.
FIG. 4 is a characteristic diagram showing a general input frequency-output signal phase characteristic of FIG. In the figure, the output phase of the CY amplifier 203 is delayed as the input frequency is increased, and the convergence correction current waveform flowing through CY9 is distorted. Therefore, in the present invention, the phase correction shown by the broken line on the characteristic diagram of FIG. 9 is performed so that the output signal phase becomes flat.

The details will be described below with reference to the waveform diagram of FIG. FIG. 10 shows a waveform of a main part of FIG. First, consider the case where a convergence correction waveform is created for the first time. An example of a correction waveform obtained when the convergence correction data generated by the DSP 801 is converted into an analog correction waveform by the D / A conversion circuit 202 is shown in FIG.
This is shown in FIG. Next, when the correction waveform is input to the CY amplifier 203, the current-voltage conversion resistor 204 causes the phase delay of the CY amplifier 203 as shown in FIG.
The influence of the phase delay of the high frequency part of the signal (a) appears, and the convergence correction waveform is distorted. The phase lag waveform is A
/ D conversion circuit 803 and DS
A comparator 805 obtains a difference from the output of P801 delayed by a predetermined time by a delay circuit 804. FIG. 10C illustrates this as a waveform image. Here, the delay amount of the delay circuit 804 is determined by the D / A conversion circuit 202 and the A / D
This is for correcting a time delay generated in the conversion circuit 803. The difference waveform (c) is added to the original waveform (a) by the DSP 801 to compensate for the effect of the phase delay in the CY amplifier 203.

Even if the convergence correction circuit 4 is configured as described above, the display device of the present embodiment corrects the convergence deviation due to terrestrial magnetism, environmental temperature and circuit phase delay, and always displays an image in an optimal convergence state. be able to.

[0037]

As described above, according to the present invention, if the convergence correction is configured as in the present embodiment, the convergence deviation due to terrestrial magnetism, environmental temperature, and circuit characteristics is corrected, and an image display is always performed in an optimal state. It can be carried out.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a configuration of a convergence correction circuit of a display device according to the present invention.

FIG. 3 is a diagram illustrating raster movement of a display device due to the influence of terrestrial magnetism.

FIG. 4 is a diagram showing an output of a geomagnetism detection circuit of a display device according to the present invention and a raster movement amount due to geomagnetism.

FIG. 5 is a diagram showing a procedure of terrestrial magnetism correction of the display device according to the present invention.

FIG. 6 is a view showing another embodiment of a display device according to the present invention.

FIG. 7 is a diagram showing a temperature drift characteristic of a CY amplifier of the display device according to the present invention.

FIG. 8 is a diagram showing a configuration of another convergence correction circuit of the display device according to the present invention.

FIG. 9 is a diagram illustrating a frequency characteristic of a CY amplifier of the display device according to the present invention.

FIG. 10 is a diagram illustrating the operation of the convergence correction circuit of FIG. 8;

FIG. 11 is a diagram showing a configuration of a conventional display device.

FIG. 12 is a diagram illustrating mislanding caused by rotation of an electron beam of a display device due to terrestrial magnetism.

FIG. 13 is a diagram showing a convergence shift of the display device due to geomagnetism.

[Explanation of symbols]

Reference Signs List 1 video circuit, 2 deflection circuit, 3 CPU, 4 convergence correction circuit, 5 rotation circuit, 6 geomagnetic detection circuit, 7, 602, 803 A / D conversion circuit,
8 CRT, 9 deflection yoke, 10 convergence correction yoke, 11 rotation coil, 201, 80
1 ... Signal processing circuit, 202 ... D / A conversion circuit, 203 ...
CY amplifier, 204: resistor, 601: temperature detection circuit, 8
04 delay circuit, 805 comparator, 121 CRT, 1
22 ... geomagnetic detection element, 123 ... current supply circuit, 12
4,125,126 ... compensation coil.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C060 BE00 CE03 CF01 CG03 CG07 CH01 HA00 HA10 HB24 HB27 JA01 5C068 AA13 AA18 HB13 HB26 JB10 MA05

Claims (4)

[Claims] 1. A video circuit to which a video signal is input, and a CR for displaying based on an output video signal of the video circuit.
T, a deflection circuit for deflecting and driving the CRT based on horizontal and vertical synchronization pulses inputted together with the video signal, a rotation circuit for outputting a correction current for performing rotation correction of a raster displayed on the CRT, A rotation coil that performs rotation correction of the CRT based on the rotation correction current, a terrestrial magnetism detection circuit that detects terrestrial magnetism, a CPU that controls the rotation circuit and the deflection circuit, and outputs a correction current that performs convergence correction of the CRT. A convergence correction circuit for performing convergence correction of the CRT based on the convergence correction current, and a convergence correction yoke provided to the CRT based on the convergence correction current. Rotate A convergence correction performance of the convergence correction circuit by adjusting a raster rotation correction amount and a vertical movement correction amount displayed on the CRT to a reference raster position by controlling the convergence correction circuit and the deflection circuit. CRT display device. 2. The deflecting circuit according to claim 1, wherein the CPU controls the deflecting circuit based on a sum of a terrestrial magnetism correction amount and a correction amount based on the input video signal as a vertical movement correction amount for controlling the deflecting circuit. A CRT display device according to any of the preceding claims. 3. A video circuit to which a video signal is input, and a CR for performing display based on an output video signal of the video circuit.
T, a deflection circuit for deflecting and driving the CRT based on horizontal and vertical synchronization pulses input together with the video signal, a rotation circuit for correcting rotation of a raster displayed on the CRT, the rotation circuit, and a deflection circuit. A CPU for controlling a circuit, a convergence correction circuit for outputting a convergence correction current for the CRT, a convergence correction yoke provided to the CRT for performing convergence correction for the CRT based on the convergence correction current, and the convergence correction circuit A display device having a temperature detection circuit for detecting an internal temperature, wherein a CPU controls the convergence correction circuit based on an output of the temperature detection circuit to compensate for an output current drift of the convergence correction circuit. C
RT display device. 4. A video circuit to which a video signal is input, and a CR for performing display based on an output video signal of the video circuit.
T, a deflection circuit for deflecting the CRT based on the horizontal and vertical synchronization pulses input together with the video signal, a convergence correction circuit for outputting a convergence correction current for the CRT, and a convergence correction current based on the convergence correction current. A display device comprising: a convergence correction yoke provided to the CRT for performing convergence correction of the CRT; and a CPU for controlling the convergence correction circuit and the deflection circuit, wherein the convergence correction circuit controls the CPU. A signal processing unit that generates a convergence correction signal based on the convergence correction yoke, a convergence amplifier unit that drives current from the convergence correction signal based on the convergence correction signal, a conversion resistor that converts a current flowing through the convergence correction yoke into a voltage waveform, Based on the converted voltage waveform,
A CRT display device, comprising: a compensation signal generation unit for compensating for a phase delay of the convergence amplifier; wherein the signal processing unit generates a convergence correction signal using the compensation signal.