JPH10262261A - Crt display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an electron beam scanning position in real time even when a display screen size and a scanning frequency, etc., are changed by correcting a counted value from a counting part based on a correction value and obtaining the horizontal scanning position coordinate of an electron beam. SOLUTION: In a figure showing the specifications of the two points of a horizontal scanning direction coordinate and a vertical scanning direction coordinate set on a CRT screen, the screen 1 of a CRT display, a display area 2 where images and characters, etc., are displayed and sawtooth-shaped waves 3 for indicating a voltage waveform for which the absolute value of a deflection current made to flow through the horizontal direction deflection coil of a CRT is converted to a voltage are displayed. Then, a timing that the electron beam is passed through by horizontal scanning on the screen is detected, counting is performed by the signals of a fixed cycle with the prescribed time phase of the horizontal scanning of the electron beam as a trigger, the correction value is calculated by comparing the counted value counted at the detected timing with the coordinate value of a reference point and the horizontal scanning position coordinate of the electron beam is obtained by correcting the counted value based on the correction value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CRT having a function of detecting a scanning position of an electron beam on a CRT display.
The present invention relates to a display and an application to convergence correction using this function.

[0002]

2. Description of the Related Art In recent years, with the advance of multimedia in information processing equipment, CRT display devices are required to faithfully reproduce images, and highly accurate convergence correction technology is required. This correction technique used a static convergence correction that combines each of the red, green, and blue display electron beams to the appropriate points using a combination of permanent magnets. Was difficult.

Therefore, as a correction method capable of correcting the entire screen, a dynamic convergence correction method has been developed in which a convergence correction coil is further provided, and a current flowing through the convergence correction coil is controlled in accordance with the scanning position of the electron beam. . Therefore,
Accurately detecting the scanning position of the electron beam has become an increasingly important technical factor.

As a conventional technique for detecting the scanning position, there is a method of obtaining a scanning position by using a linear function circuit using a clock as a variable and a turning point at the right end of the screen as a function starting point. In this method, it is necessary to give the “slope” of a linear function depending on the scanning speed and the “scanning start point” as initial values. Therefore, when changing the display screen size, the display screen position, and the scanning frequency, a function for calculating the screen size and the display position is prepared beforehand, and the microprocessor mounted on the CRT display device is used to change the screen size and the display position. The “tilt” and “scanning start point” were calculated and given to the linear function.

[0005]

However, the above prior art has the following problems. That is, every time the display screen size, the display position, or the scanning frequency is changed, an expensive microprocessor is mounted on a CRT display device or the like in order to execute a large amount of calculation for obtaining the “tilt” and “scanning start point”. In addition, there is a problem that a microprocessor is occupied by the arithmetic processing and other processing is difficult.

The present invention has a new technical problem of detecting the electron beam scanning position in real time even when the display screen size, the display position, and the scanning frequency are changed in order to avoid the problems of the conventional technology. With the goal of solving
It is an object of the present invention to provide a CRT display device having a scanning position detecting means for achieving the above object and a CRT display device having a convergence correction function using this means.

[0007]

In order to achieve the above object, a novel concept of the present invention is to set the scanning position of the electron beam to C
It is to detect as a coordinate position indicating the position in the horizontal scanning direction and the vertical scanning direction set on the RT screen. The principle of this new idea will be described with reference to FIG. 1 by taking as an example a case where the position of the electron beam in the horizontal scanning direction is detected.

FIG. 1 is a diagram showing horizontal scanning direction coordinates and vertical scanning direction coordinates set on a CRT screen, and designation of two points in the horizontal scanning direction. In FIG. 1, 1 indicates a screen of a CRT display. Reference numeral 2 denotes a display area in which images, characters, and the like are displayed, and reference numeral 3 denotes a sawtooth wave representing a voltage waveform obtained by converting an absolute value of a deflection current flowing through a horizontal deflection coil of a CRT into a voltage.

Although the coordinates can be set arbitrarily, a case where the image is divided into 256 in the horizontal scanning direction will be described as an example. Now, a line passing through the coordinate value 64 in the horizontal scanning direction is defined as an A line, and a line passing through the coordinate value 128 in the horizontal scanning direction is defined as a B line.

If the point at which the electron beam intersects the line A is taken as a reference point, the coordinate value of this point in the horizontal scanning direction is always 64. Similarly, if the point at which the electron beam intersects the line B is taken as a reference point, Is always 128 in the horizontal scanning direction. That is, if a reference point at which the scanning line of the electron beam intersects the A line or the B line is detected, the coordinate value of the scanning point of the electron beam in the horizontal scanning direction at that time regardless of the scanning frequency, the screen size, and the screen position. Is found.

The timing at which the electron beam scans the A-line is determined by comparing the saw-tooth wave 3 of FIG. 1 with the A-line detection reference voltage 4 using a comparator or the like. It can be detected as the rising point.

In the same manner, the timing at which this electron beam scans on the B line is compared with the B line detection reference voltage 5 and the voltage of the sawtooth wave 3 to determine the rising point of the square wave of the B line detection signal 7. Can be detected.

According to the method described above, the electron beam is
The timing of each reference point crossing the A line and the B line is determined, and a clock that generates 64 clocks between the A line and the B line is generated by the multiplier circuit.
, The count value becomes the coordinate value of the scanning point in the horizontal scanning direction as it is.

Although the clock is generated from two reference points, the clock is generated by a known circuit or a microcomputer so that even if only the reference point where the A-line and the electron beam intersect is used, this clock is used. If the counting is performed with the A-line passing time being 64, the counted value becomes the coordinate value of the scanning point in the horizontal scanning direction as it is.

In principle, the coordinate values in the horizontal direction are obtained as described above. However, the position scanned before the reference point where the A-line and the electron beam cross must also be counted by a clock. It is necessary to correct counting errors due to variations in horizontal scanning frequency and scanning current amplitude. Therefore, A
It is preferable to use an accurate and stable signal as a trigger for starting the clock counting, such as a retrace start point 50 in FIG. 1 which is a time phase before the reference point where the line and the electron beam cross. At the retrace start point 50, the clock is counted, and the difference between the count value of the clock when the electron beam reaches the reference point and the coordinate value of the reference point is determined. By adding the correction value to the count value of the clock, correct coordinates of the horizontal scanning position of the electron beam can be obtained.

On the other hand, in the vertical direction, it is possible to detect the vertical scanning position similarly to the horizontal direction by using the vertical scanning sawtooth wave. However, for example, in the case of a television, since the vertical direction is scanned at a period of 33.3 ms which is 525 times the horizontal direction, if the vertical scanning position is detected simply by the same method as in the horizontal direction, for example,
The clock cycle of the position detection becomes longer, which is likely to cause inconvenience in the circuit configuration and the detection accuracy. It is preferable to use a clock with a shorter cycle, for example, a clock used for horizontal position detection.

Therefore, in order to determine the vertical scanning position, the number of periodic clocks required for the electron beam to scan one coordinate in the vertical direction is defined as a decimal number, and the coordinate value in the vertical direction is associated with each decimal number. It should be done.

According to the first aspect of the present invention, based on the above principle, in order to achieve the above object,
A horizontal direction detection unit that detects the timing at which the electron beam passes the reference point on the screen by horizontal scanning, and a counting unit that counts with a signal of a constant cycle, triggered by a predetermined time phase of the horizontal scanning of the electron beam, A correction value calculation unit that calculates a correction value by comparing a count value counted by the counting unit with a coordinate value of the reference point at a timing detected by the horizontal direction detection unit; and a calculated correction value. Based on the above, by correcting the count value from the counting unit,
A gist of the present invention is a CRT display device including a horizontal position calculating unit for obtaining horizontal scanning position coordinates of an electron beam, and a horizontal position detecting unit.

Therefore, according to the first aspect of the present invention, even if the display screen size, the display position, and the scanning frequency are changed, the horizontal scanning position of the electron beam on the CRT screen can be changed in real time without performing a large amount of calculation. Can be sought.

According to the second aspect of the present invention, the vertical direction detecting section for detecting the timing at which the electron beam passes through the reference point on the screen by vertical scanning, and the timing detected by the vertical direction detecting section is fixed. From the periodic signal,
A period counting unit for calculating the number of periodic clocks per coordinate value in the vertical scanning direction of the electron beam; and a predetermined time phase of the vertical scanning of the electron beam is used as a trigger to count with the signal of the constant period and to calculate the number of periodic clocks. A carry count unit that counts the carry as a base, and a correction value is calculated by comparing the count value counted by the carry count unit and the coordinate value of the reference point at the timing detected by the vertical direction detection unit. A vertical position detection unit comprising: a correction value calculation unit; and a vertical position calculation unit that calculates a vertical scanning position coordinate of the electron beam by correcting the count value from the carry counting unit based on the calculated correction value. And a CRT display device comprising:

Therefore, according to the second aspect of the present invention, even if the display screen size, the display position, and the scanning frequency are changed, the vertical scanning position of the electron beam on the CRT screen can be changed in real time without performing a large amount of calculation. Can be sought.

According to a third aspect of the present invention, there is provided a horizontal direction detecting section and a horizontal position detecting section according to the first aspect, and a vertical direction detecting section and a horizontal position detecting section according to the second aspect,
A CRT display device comprising: a correction unit for correcting convergence of an electron beam for scanning a screen divided into a plurality of blocks for each block; and a correction data holding unit for holding correction data corresponding to the block. And

Therefore, according to the third aspect of the present invention, even if the display screen size, the display position, and the scanning frequency are changed, the horizontal scanning position of the electron beam on the CRT screen can be changed without performing a large amount of calculation. The scanning position can be obtained in real time, and convergence correction can be performed in real time without performing a large amount of calculation even if the display screen size, the display position, and the scanning frequency are changed.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] As a preferred embodiment of the present invention, a horizontal scanning position and a vertical scanning position of an electron beam are simultaneously detected, and two points in the horizontal scanning direction and two points in the vertical scanning direction are set. The case is described.

FIG. 2 is a diagram showing a basic configuration of the present embodiment, FIG. 3 is a diagram showing an embodiment of a deflection current detection unit comprising a horizontal direction detection unit and a vertical direction detection unit, and FIG. FIG. 5 is a diagram illustrating an operation description (1) of the current detection unit, FIG. 5 is a diagram illustrating an operation description (2) of the deflection current detection unit, and FIG. 6 is a diagram illustrating an embodiment of the horizontal position detection unit. FIG. 7 is a diagram showing an embodiment of the vertical position detecting unit.

In the basic configuration of FIG. 2, the horizontal direction detector 12 and the vertical direction detector 1 constituting the deflection current detector 10 are provided.
3 converts a sawtooth current flowing through a deflection coil of a CRT into a voltage waveform, compares the voltage waveform with a reference voltage, generates a horizontal scanning position signal and a vertical scanning position signal, and converts each signal into a horizontal signal. It is sent to the position detecting section 60 and the vertical position detecting section 70.

In this embodiment, the horizontal position detecting section 60 generates a clock based on the horizontal scanning position signal, and generates and outputs horizontal scanning position coordinates by calculation or the like.

In this embodiment, the vertical position detecting section 70 generates and outputs vertical scanning position coordinates by calculation or the like based on the vertical scanning position signal and the clock. The horizontal scanning position coordinates and the vertical scanning position coordinates are output to a signal processing unit (not shown) or the like.

Next, a method for obtaining a horizontal scanning position signal will be described with reference to FIGS. In FIG. 3, a deflection current detector 10 includes a CRT 11, a horizontal direction detector 12,
The vertical direction detection unit 13 includes a vertical direction detection unit 13.
The horizontal deflection output circuit 20, the horizontal deflection coil 21, the current-voltage converter 22, the first reference voltage 23, the first comparator 24, the second reference voltage 25, and the second comparator 26 The vertical direction detection unit 13 includes a vertical deflection output circuit 30, a vertical deflection coil 31, a current-voltage conversion unit 32, a third reference voltage 33, a third comparator 34, and a fourth reference voltage 35. And a fourth comparator 36.

In FIG. 4, for simplicity of explanation, the coordinates on the screen of this embodiment are from 0 to 255 by dividing the horizontal scanning direction into 256. In the present embodiment, two points used for obtaining the horizontal scanning direction coordinates are points A on the same scanning line and having a horizontal scanning direction coordinate of 64, and a point B having a horizontal scanning direction coordinate of 128 is referred to as a point B 42. I do.

In FIG. 3, the horizontal deflection output circuit 20 outputs a horizontal scanning sawtooth current for scanning the electron beam in the horizontal direction to the horizontal deflection coil 21 and starts the retrace of the horizontal scanning sawtooth current. A horizontal scanning retrace start signal HFBP indicating a point (retrace start point 50 shown in FIG. 4) is output to the horizontal position detector 60. The horizontal scanning sawtooth current that has flowed through the horizontal deflection coil 21 is input to the current-to-voltage converter 22, where the absolute value of the current is converted into a voltage, which results in a voltage waveform indicated by the horizontal scanning sawtooth 45 shown in FIG.

Next, the first reference voltage 23 is set in advance to a first voltage 46 generated in the current-voltage converter 22 when the electron beam scans the point A 41, and the second reference voltage 23 is also set. A voltage of 25 is set in advance to a second voltage 47 generated in the current-voltage converter 22 when the electron beam scans the point B.

The first comparator 24 compares the input horizontal scanning sawtooth wave 45 with the first reference voltage 23, and outputs a signal HCSQ 48 which becomes high level only during the period when the horizontal scanning sawtooth wave 45 exceeds the first reference voltage 23. Output. Similarly, the second comparator 26 compares the input horizontal scanning sawtooth wave 45 with the second reference voltage 25, and outputs a signal HCSH49 that becomes a high level only during a period in which the horizontal scanning sawtooth wave 45 exceeds the second reference voltage 25. I do.

The deflection current detector 10 outputs the signals HCSQ48, HCSH49 and HFBP described above to the horizontal position detector 60 as horizontal scan position signals. Next, a method for obtaining a vertical scanning position signal will be described with reference to FIGS.

In this embodiment, the points C and D shown in FIG. 5 are used to determine the coordinates in the vertical scanning direction. C
Point 43 has a coordinate in the vertical scanning direction of 64, and point D has a coordinate in the vertical scanning direction of 128. In the present embodiment, the coordinates in the horizontal scanning direction are the same.

In FIG. 3, a vertical deflection output circuit 30 outputs a vertical scanning sawtooth current for scanning an electron beam in the vertical direction to a vertical deflection coil 31, and a retrace start point of the vertical scanning sawtooth current. A vertical scanning retrace start signal VFBP indicating (retrace start point 52 shown in FIG. 5) is output to the vertical position detector 70. The vertical scanning sawtooth current flowing through the vertical deflection coil 31 is input to the current / voltage converter 32, and the absolute value of the current is converted into a voltage, which results in a voltage waveform indicated by the vertical scanning sawtooth 51 in FIG.

Next, the third reference voltage 33 is set in advance to a third voltage 53 which is a voltage generated in the current-to-voltage converter 32 when the electron beam scans the point C 43, The reference voltage 35 is preset to a fourth voltage 54 which is a voltage generated in the current-voltage converter 32 when the electron beam scans the point D 44.

The third comparator 34 compares the input vertical scanning sawtooth wave 51 with the third reference voltage 33, and outputs a signal VCSQ55 which becomes high only during the period when the vertical scanning sawtooth wave 51 exceeds the third reference voltage 33. Is output.
Similarly, the fourth comparator 36 compares the input vertical scanning sawtooth wave 51 with the fourth reference voltage 35, and outputs a signal VCSH 56 which becomes a high level only during a period when the vertical scanning sawtooth wave 51 exceeds the fourth reference voltage 35. Output.

The deflection current detector 10 outputs the signals VCSQ55, VCSH56, and VFBP described above to the vertical position detector 70 as vertical scanning position signals. Using the horizontal scanning position signal and the vertical scanning position signal described above, the coordinates of the scanning point of the electron beam are obtained in the horizontal position detecting section 60 and the vertical position detecting section 70 as follows.

First, the detection of the horizontal scanning position coordinates will be specifically described with reference to FIG. The multiplying circuit 61 detects the rising of each of the signals HCSQ48 and HCSH49, and oscillates a 64-fold frequency in the case of the present embodiment using the rising time intervals to generate a clock.
By counting the time during which the electron beam scans between point A 41 and point B 42 with this clock, the count value becomes 64 irrespective of the scanning frequency or the scanning current amplitude.

After the signal HCSQ48 rises,
The clock can be used to count the coordinates, but the signal HCS
The configuration and operation for counting before Q48 rises and for correcting counting errors due to fluctuations in horizontal scanning frequency and scanning current amplitude will be described in detail below.

The differentiating circuit 62 and the counter 63 correspond to the counting unit 10
0. The signal HFBP and the clock are input to the differentiating circuit 62, and the signal HFBP is synchronously differentiated by the clock to generate a reset signal for the counter 63. The counter 63 is cleared by the reset signal at the start of horizontal retrace (indicating the retrace start point 50 in FIG. 4), and continues counting clocks.

The differentiating circuit 64, the register 65, and the subtracting circuit 67 constitute a correction value calculating section 110. Differentiating circuit 64
Receives the signal HCSQ48 and the clock,
The signal HCSQ48 is differentiated synchronously with the clock to generate a write start signal for the register 65. This write start signal is input to the register 65, and the count value of the counter 63 at that time is stored in the register 65. That is, the value of the counter 63 at the time when the electron beam scans the point A 41 shown in FIG. 4 is stored in the register 65. The value of the counter 63 at the time when the electron beam scans the point A should be 64 in the present embodiment, but the value of the counter 63 has an error due to the fluctuation of the horizontal scanning frequency and the scanning current amplitude. Therefore, a result obtained by subtracting the value of the register 65 from the coordinate value of the point A 41 by the subtraction circuit 67 is output as a correction value to the horizontal position calculation unit 68 including the addition circuit.

In the horizontal position calculation section 68, the subtraction circuit 6
7 and the value of the counter 63 are added and output as a horizontal scanning position coordinate value. The calculation of this correction is expressed by the following equation.

Horizontal scanning position coordinate value = (value of counter 63) + 64− (value of register 65) In the above description, the horizontal scanning position of the electron beam is determined by the signal HF.
Although the counting is performed with the BP as a trigger, the counting may be performed with, for example, a scanning start point of a horizontal scanning sawtooth wave or another time phase.

Next, the detection of the vertical scanning position coordinates will be specifically described with reference to FIG. Since the vertical scanning period is longer than the horizontal scanning period, it is not practical to generate a clock using the method of the multiplying circuit used in the horizontal position detection unit 60. In this embodiment, the clock generated by the multiplying circuit 61 of the horizontal position detector 60 is also used in the vertical position detector 70.

The cycle counting section 120 includes a differentiating circuit 71, a differentiating circuit 72, a counter 74, a register 75, and a divider 76. The differentiating circuit 71 receives the signal VCSQ.
The differential circuit 72 synchronously differentiates the signal VCSH 56 with the clock, and outputs a rising detection signal of each input signal. After being cleared by the rising edge detection signal of the signal VCSQ55, which is the output of the differentiating circuit 71, the counter 74 continues counting the clock generated by the multiplying circuit 61 and outputs the counter value to the register 75. The register 75 outputs the signal VCSH56 to the differentiating circuit 72.
A rising detection signal of the signal VCSH 56 obtained by synchronous differentiation is used as a write start signal, and the value of the counter 74 is read and stored. The value stored in the register 75 is the count value of the clock during the scanning of the point C and the point D shown in FIG. 5 by the electron beam. Next, divider 76
Outputs a value obtained by dividing the stored value of the register 75 by 64 in this embodiment. This value is the number of periodic clocks between one coordinate in the vertical scanning direction.

As in the case of detecting the horizontal scanning position, in the vertical scanning position detection, the counting is performed before the signal VCSQ55 rises, and the counting error is corrected by the fluctuation of the horizontal scanning frequency and the scanning current amplitude. The operation will be described in detail below.

The carry counter 130 comprises the universal number counter 77 and the counter 78, and the universal number counter 7
Reference numeral 7 denotes a detection signal obtained by synchronously differentiating a signal VFBP indicating a vertical retrace start point (return start point 52 in FIG. 5) triggered by the start of vertical counting in the present embodiment by a differentiating circuit 73. After being cleared, the clock is counted using the number of periodic clocks from the divider 76 as a measurement base, and a carry is output to the counter 78 for each clock number between one coordinate in the vertical scanning direction.

The carry value, which is the output of the counter 78, should be 64 in this embodiment when the electron beam scans the point C which is the reference point. May cause an error.

Therefore, the correction value calculation unit 140 including the register 79 and the subtraction circuit 80 sets the following values so that the vertical scanning position coordinate value at the time when the signal VCSQ 55 rises becomes 64 which is a correct value in the present embodiment. Compute the correction.

The register 79 stores the carry value of the counter 78 at the time when the signal VCSQ rises, using the rising detection signal of the signal VCSQ55 which is the output of the differentiating circuit 71 as a write start signal, and outputs the carry value to the subtraction circuit 80. The subtraction circuit 80 subtracts this carry value from 64, which is the vertical scanning direction coordinate of the point C 43, and outputs a correction value, which is the result of the subtraction, to a vertical position calculation unit 81 composed of an addition circuit. The vertical position calculation unit 81 adds the value of the counter 78 and the correction value and outputs the result as a vertical scanning position coordinate value.

The calculation of this correction is expressed by the following equation. Vertical scanning position coordinate value = (value of counter 78) +
In the above description, the vertical scanning position of the electron beam is measured based on the signal VFBP indicating the retrace start point 52 of the vertical scanning sawtooth wave 51. For example, the scanning of the vertical scanning sawtooth wave is performed. A starting point or another time phase may be used as a measurement reference.

In the above description, the multiplying circuit 61 of the horizontal scanning position detector is used as the clock for detecting the vertical scanning position.
A clock generated by multiplying or dividing the clock, a clock using the periodicity of a horizontal scanning sawtooth wave, or a clock generated by multiplying the C point 43 and the D point 44 has been described. Etc. may be used.

In the description of the above embodiment, the CRT display device capable of simultaneously detecting the horizontal scanning position and the vertical scanning position has been described as a preferred embodiment. 3. A CRT display device comprising a horizontal direction detecting unit and a horizontal position detecting unit for detecting a horizontal scanning position, or a vertical direction detecting unit and a vertical position detecting unit as described in claim 2. It is possible to easily implement a CRT display device characterized by performing vertical scanning position detection by providing a CRT display unit.

In the description of the above embodiment, the horizontal scanning position is detected based on only two points on one horizontal scanning line. However, the horizontal scanning position is accurately detected with respect to fluctuations in the scanning frequency and the scanning current amplitude. In order to detect the position, it is preferable to perform the above-described horizontal scanning position detection each time each horizontal scanning is repeated.

In the above description of the embodiment, the horizontal scanning position is detected based on only two points on one horizontal scanning line. However, the horizontal scanning position is accurately detected with respect to the fluctuation of the scanning frequency and the scanning current amplitude. In order to detect the horizontal scanning position, the horizontal scanning position may be detected based on three or more points.

In the above description of the embodiment, the vertical scanning position is detected based on two addresses in the same horizontal scanning direction in one frame or one field. In order to accurately detect the vertical scanning position with respect to the fluctuation of the current amplitude, the vertical scanning position may be detected based on three or more points.

The reference voltages 23, 25, 33, and 35 of the deflection current detection unit 10 described in the above embodiment may be set to a desired voltage value by dividing a single power supply. Further, as a method of setting a desired voltage value, a configuration in which a set value of a voltage can be easily set using a variable resistor or a D / A converter or a configuration combined with a single power supply may be used.

The horizontal position detector 60, the vertical position detector 70, or a part of the function of the horizontal position detector 60 or a part of the function of the vertical position detector 70 may be performed by a microprocessor or the like.

Further, the multiplying circuit 6 described in the above embodiment is used.
1 generates a clock having 64 clocks between the point A 41 and the point B 42, but preferably generates a clock such as 32 clocks, 128 clocks, or 256 clocks.
A configuration may be employed in which a clock is generated that is a fraction of the difference between the coordinate values between the points 42 or an integer multiple.

In the description of the above embodiment, the coordinate values in the horizontal scanning direction and the vertical scanning direction are the same in both directions from 0 to 2.
Although set to 56, it may be set to a different value, or may be set to a value of preferably a power of 2, such as from 0 to 127, or from 0 to 511, or from 0 to 1023.

In the above embodiment, the horizontal position detection and the vertical position detection are each performed based on two points and a clock is generated. However, based on one point each, a well-known circuit or microprocessor is used. May be used.

The CRT display device provided with the above-described scanning position detecting means according to the present invention has the following effects. (1) It is possible to detect the position scanned by the electron beam without depending on the scanning frequency, the display screen size, and the display screen position. (2) The position scanned by the electron beam can be detected in real time. (3) The position where the electron beam scans can be detected without using a microprocessor.

[Second Embodiment] The second embodiment is directed to a third embodiment.
FIG. 8 shows a convergence correcting means in this embodiment.

The feature of this embodiment is that the scanning position of the electron beam detected by the first and second aspects of the present invention is used to make the CRT of the CRT independent of the size of the display screen, the screen display position and the scanning frequency. It is to realize dynamic convergence correction for correcting color misregistration.

In FIG. 8, the correction data holding means 91 is a memory storing correction information, and stores, for example, correction information for each of 256 blocks obtained by dividing the CRT screen into 16 parts in the horizontal scanning direction and the vertical scanning direction. ing. Correction means 9
Reference numeral 0 denotes a control unit 92, a correction coil driving unit 93, and a convergence correction coil 94. When the horizontal scanning position coordinates and the vertical scanning position coordinates are input, the control unit 92 stores the correction data of the corresponding block in the correction data holding unit. The correction data is read out from the control unit 91 and sent to the correction coil driving unit 93. The correction coil driving section 93 sends a correction current corresponding to the correction data to the convergence correction coil 94 to perform convergence correction.

The CRT display device characterized in that the correction current according to the present invention described above is supplied to the convergence correction coil has the following effects in addition to the effects of the first embodiment. (1) Dynamic convergence correction can be performed without using a microprocessor without depending on the scanning frequency, the display screen size, and the display screen position.

[0069]

As described above in detail, according to the first aspect of the invention, the horizontal scanning in which the electron beam scans in real time without depending on the scanning frequency, the display screen size or the display screen position. The position can be detected.

Further, according to the second aspect of the invention, it is possible to detect the vertical scanning position where the electron beam is scanning in real time without depending on the scanning frequency, the display screen size, and the display screen position. .

According to the third aspect of the invention, in addition to the effects of the first and second aspects, dynamic convergence correction can be performed in real time without depending on the scanning frequency, the display screen size, and the display screen position. Become.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the invention.

FIG. 2 Basic configuration

FIG. 3 is a deflection current detector

FIG. 4 explains the operation of a deflection current detection unit (1).

FIG. 5 illustrates the operation of the deflection current detector (2).

FIG. 6 is a horizontal position detection unit.

FIG. 7 is a vertical position detecting unit.

FIG. 8 shows the configuration of convergence correction.

[Explanation of symbols]

 1 screen 10 deflection current detection unit 12 horizontal direction detection unit 13 vertical direction detection unit 45 horizontal scanning sawtooth 51 vertical scanning sawtooth 60 horizontal position detection unit 70 vertical position detection unit 100 counting unit 110 correction value calculation unit 120 cycle counting unit 130 Carry counting section 140 Correction value calculation section

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 3/22 H04N 3/22 D 3/26 3/26

Claims (3)

[Claims] 1. A horizontal direction detecting unit for detecting a timing at which an electron beam passes a reference point on a screen by horizontal scanning, and counting a signal with a constant period by a predetermined time phase of the horizontal scanning of the electron beam. A counting unit for performing, a correction value calculating unit that calculates a correction value by comparing a count value counted by the counting unit with a coordinate value of the reference point at a timing detected by the horizontal direction detecting unit, A horizontal position calculating unit that obtains the horizontal scanning position coordinates of the electron beam by correcting the count value from the counting unit based on the calculated correction value. Characteristic CRT display device. 2. A vertical direction detecting section for detecting a timing at which an electron beam passes through a reference point on a screen by vertical scanning, and a timing of the electron beam and a signal of a constant period detected by the vertical direction detecting section. A period counting unit for calculating the number of periodic clocks per one coordinate value in the scanning direction; and a carry which counts with the signal of the constant period and makes the number of periodic clocks a decimal number, triggered by a predetermined time phase of the vertical scanning of the electron beam. And a correction value calculating unit that calculates a correction value by comparing the count value counted by the carry counting unit and the coordinate value of the reference point at the timing detected by the vertical direction detecting unit. And correcting the count value from the carry counting unit based on the calculated correction value to obtain the vertical scanning position coordinates of the electron beam. CRT display device comprising a position calculating unit, and the vertical position detector consisting, further comprising a. 3. A screen having a horizontal direction detecting unit and a horizontal position detecting unit according to claim 1 and a vertical direction detecting unit and a vertical position detecting unit according to claim 2, wherein a screen divided into a plurality of blocks is displayed. A CRT display device, comprising: correction means for correcting convergence of an electron beam to be scanned for each block; and correction data holding means for holding correction data corresponding to the block.