JPH08223594A - Auto-static convergence correction device and image display device using the device - Google Patents

Abstract

(57) [Summary] [Purpose] To accurately output a screen edge detection signal and to easily output a screen edge detection signal to an arbitrary scanning line position even if the number of scanning lines of the input signal changes. [Structure] A counter 1 receives a vertical synchronizing signal 11 as a clear input, counts a horizontal synchronizing signal 10, and outputs a current scanning line number 14. On the other hand, the microprocessor unit 4 writes the screen edge scanning line number 17 in the data latch 2 in advance. The comparator 3 compares the current scanning line number 14 with the screen end scanning line number 13 from the data latch 2, and when the two scanning line numbers match, outputs a screen end detection signal 15 and outputs a microprocessor unit. On-screen reference signal from 4
Enable 16

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for an automatic static convergence correction device, which is applied to, for example, a projection type color image receiver and the like, for automatic adjustment of deviation in display position of images and automatic correction of static convergence. In particular, the present invention relates to an image display device using a screen edge detection signal generator and its correction device.

[0002]

2. Description of the Related Art Generally, in a projection type color image receiving apparatus for enlarging and projecting on a screen by using three projection tubes which emit three primary colors, an incident angle of the projection tube with respect to the screen is different on each screen. Color shift occurs.

In order to realize the superposition of these three primary colors, a so-called digital convergence correction device as shown, for example, in Japanese Patent Laid-Open No. 5-244615 is often used. This digital convergence correction device is provided with adjustment points synchronized with the horizontal and vertical scanning periods, digitally writes convergence correction amount data for each adjustment point into a frame memory, and reads out this data for D / A conversion. , Convergence correction Waveform signal is created to perform convergence correction. At this time, in the vertical direction, the correction data is used to calculate the correction data on the scanning line between the correction points.
Further, in the horizontal direction, the correction data is smoothed using an analog LPF circuit.

However, conventionally, in a projection type color image receiver, the position of the raster itself may be statically changed due to the geomagnetism which differs depending on the position and orientation of the device installation, and the temperature change peculiar to the device. In many cases, the deviation cannot be automatically corrected by the digital convergence correction device.

A device that automatically corrects this deviation is an autostatic convergence correction device. FIG. 3 is a block diagram showing the configuration of a conventional auto static convergence correction device, and will be simply referred to as a correction device hereinafter.
In the correction device of FIG. 3, 4 is a microprocessor unit (hereinafter referred to as MPU), 6 is a horizontal synchronization signal delay device, 7 is a screen edge detection signal generator, 8 is a video switcher, 9 is a video display screen, and 19 is a video display screen. Optical sensor, 23 is a video amplifier,
Reference numeral 24 is an amplified video signal, 25 is a CRT, 27 is a D / A converter, 28 is a convergence yoke, and 33 is a switch.

In this correction device, the horizontal synchronizing signal 10 is delayed by the horizontal synchronizing signal delay device 6, and a horizontal pulse 12 is provided.
The on-screen display device built in the MPU 4 uses the vertical synchronizing signal 11 to output the on-screen reference signal 16 for auto-static convergence to a preset position. This on-screen reference signal 16
Is output to the video switch 8 via the switch 33 that is closed by the screen edge detection signal 15 output from the screen edge detection signal generator 7 using the vertical sawtooth signal 18. The on-screen reference signal 16 includes the normal video signal 21 and the video switch 8
The mixed signal 22 is input to the video amplifier 23, and the video signal 24 amplified thereby is input to the CRT 25, which is displayed on the screen display screen 9.

Also, the on-screen reference signal 16 is
It is detected by the optical sensor 19 and sent to the MPU 4 as a reference signal detection signal 20. Then, the MPU 4 compares the position of the on-screen reference signal 16 with the position of the normal-time on-screen reference signal 16 stored in advance, and calculates the difference as the deviation of the static convergence. Then, the calculation result is output to the D / A converter 27 as the D / A converter control signal 26. Then, the D / A converter 27 outputs a static correction signal to the convergence yoke 28 according to the D / A converter control signal 26. As a result, it is possible to automatically correct the deviation of the static convergence.

Next, FIG. 4 is a circuit diagram showing the configuration of the screen edge detection signal generator of FIG. In FIG. 4, 29 is a comparator, 30 is a fixed resistor, and 31 is a semi-fixed resistor. In the screen edge detection signal generator 7, the vertical sawtooth wave signal 18 and the DC voltage 32 determined by the two fixed resistors 30 and the semi-fixed resistor 31 are compared by the comparator 29, and when both voltages become equal, the screen edge detection is performed. Output signal 15.

[0009]

However, in the above configuration, the semi-fixed resistors 31 must be adjusted one by one so that the screen edge detection signal 15 can be output stably.
In addition, the screen edge detection signal 15 becomes unstable due to variations in the constant of the semi-fixed resistance and the characteristics of the comparator, and changes in the resistance value due to temperature changes, etc., and the performance is inferior in the static convergence correction time. There is a drawback that.

Further, when there are a plurality of frequencies of the horizontal synchronizing signal 10 of the video signal input to the projection type color receiver,
In the above configuration, depending on the frequency of each horizontal synchronization signal,
A circuit in which constants of resistors and capacitors are optimized is required, and when used in a multi-scan monitor supporting multiple frequencies, a large number of comparator circuits and switching circuits are required.

In view of the above-mentioned drawbacks, the present invention improves the convergence correction accuracy of the auto static convergence correction device by obtaining the stability of the screen edge detection signal with respect to temperature changes, and improves the auto static convergence correction for multiple frequencies. An object of the present invention is to provide a correction device capable of

[0012]

In order to achieve the above object, the present invention detects the current raster position using an optical sensor installed outside the screen for displaying an image and presets it. In the automatic static convergence correction device that calculates the deviation from the position as the deviation amount of static convergence in the microprocessor unit and corrects the convergence of the electron beam that scans the screen according to the amount, A first means is a counter that counts horizontal synchronizing signals with a vertical synchronizing signal as a clear input and outputs the current number of scanning lines,
A microprocessor unit for writing in the data latch the number of screen edge scanning lines which is the comparison latch setting data for both edges of the screen from the vertical and horizontal synchronizing signals, the current number of scanning lines from the counter and the screen edges from the data latch Comparing the number of scanning lines at the screen edge which is the comparison latch setting data, and outputting a screen edge detection signal when they match, the on-screen reference signal from the microprocessor unit is generated by the screen edge detection signal. Is effective.

The second means of the screen edge detection signal generating section receives the vertical and horizontal synchronizing signals, counts the current number of scanning lines from the horizontal synchronizing signal, and reaches the preset number of screen edge scanning lines. Then, a second microprocessor unit that outputs a screen edge detection signal and a first microprocessor unit that receives the vertical and horizontal synchronization signals as an input and that validates and outputs an on-screen reference signal based on the screen edge detection signal. It is characterized by having.

[0014]

According to the present invention, the current scanning line is counted from the horizontal synchronizing signal and compared with the number of scanning lines at the screen edge set in advance at the screen edge to determine the screen edge at the screen edge of the video display screen. The detection signal can be obtained accurately. Furthermore, even if the number of scanning lines of the input video signal (horizontal synchronizing signal) changes, the screen edge detection signal can be easily output to an arbitrary scanning line position.

Further, according to the present invention, since the screen edge detection signal is not obtained by the combination circuit of the semi-fixed resistor and the comparator which requires adjustment one by one in the screen edge detection signal generating section as in the prior art, the humidity is reduced. Makes it less susceptible to changes.

[0016]

Embodiments of the present invention will be described below.
FIG. 1 is a block diagram showing a configuration of a screen edge detection signal generating section of an automatic static convergence correction device according to a first embodiment of the present invention (claim 1).

In FIG. 1, reference numeral 1 denotes a counter which receives a vertical synchronizing signal 11 as a clear (CLR) input, a horizontal synchronizing signal 10 as a count, and outputs a current scanning line number 14. 2 is a data latch, which is MP which is comparison latch setting data at both ends of the screen
The number of screen edge scanning lines 17 is written from U4. Reference numeral 3 denotes a comparator, which compares the current scanning line number 14 from the counter 1 with the screen edge scanning line number 13 which constantly outputs the screen edge scanning line number 17 written in the data latch 2, Screen edge detection signal when both scanning lines 14 and 13 match
Outputs 15. Other than that, the same components as those in the conventional example shown in FIG.

The operation of FIG. 1 will now be described. The counter 1 counts the horizontal synchronizing signal 10 and the current scanning line number is 14
Is output. On the other hand, the MPU 4 uses the horizontal pulse 12 obtained by delaying the horizontal synchronizing signal 10 by the horizontal synchronizing signal delay device 6 and the vertical synchronizing signal 11 to create the screen end scanning line number 17 and outputs it to the data latch 2 for writing. As for the screen end scanning line number 17 written in the data latch 2, the screen end scanning line number 13 is always output from the data latch 2. Here, by rewriting the number of screen edge scanning lines 17 written in the data latch 2, it is possible to easily change to any scanning line position. That is, one circuit can handle the frequencies of many horizontal synchronizing signals.

The comparator 3 determines the number of the two scanning lines.
When 13 and 14 are compared and the numbers of the two scanning lines match, the screen edge detection signal 15 is output to the switch 33.

The switch 33 switches from the current solid line position to the broken line position according to the screen edge detection signal 15, and outputs the on-screen reference signal 16 from the MPU 4 as valid. The following operation is mixed with the video signal 21 by the video switch 8 and output to the CRT 25 as described in the conventional example of FIG.

As described above, according to this embodiment, by using the count data obtained by counting the horizontal synchronizing signal itself, the screen edge detection signal can be accurately output even if the number of scanning lines of the horizontal synchronizing signal changes. it can.

In the configuration of FIG. 1 described above, as a third embodiment, without using the data latch 2, the number 17 of screen edge scanning lines output from the MPU 4 is a fixed value, that is, originally output from the data latch 2. Number of screen edge scan lines to be done
The comparator 3 has 13 as a fixed value so as to be compared with the current number of scanning lines 14 (claim 3).

According to this structure, the components of the data latch 2 are omitted, which is simplified and the cost is reduced.

Further, in the configuration of FIG. 1, as a fourth embodiment, the data latch 2 is not used and the MPU 4 is used as described above.
The number 17 of scanning lines at the end of the screen output from is directly compared with the current number 14 of scanning lines (claim 4).

Also in the case of this structure, the same structural effect as that of the third embodiment is obtained.

In the configuration of FIG. 1, as the fifth embodiment, the number of screen edge scanning lines set in the data latch 2 is 17 depending on the frequency of the horizontal synchronizing signal input to the MPU 4.
(Claim 5).

With this configuration, it is possible to perform auto static convergence correction for multiple frequencies.

Further, in the configuration of FIG. 1, as a seventh embodiment, the MPU 4 which sets the number 17 of scanning lines at the screen edge controls the operation of the automatic static convergence correction device. It can also be used as an MPU not shown (Claim 7).

According to this structure, the MPU 4 can be omitted, which simplifies and reduces the cost.

Further, in the configuration of FIG. 1, the MPU 4 for setting the screen end scanning line number 17 as the ninth embodiment can also be used as an MPU (not shown) for controlling the operation of the entire image display apparatus. 9).

Also in this case, the same structural effect as that of the seventh embodiment can be obtained.

Further, in the configuration of FIG. 1, as a tenth embodiment, the screen edge detection signal generator of the auto static convergence correction device shown in FIG.
When used in the image display device including the video display screen 9 and the CRT 25 shown in (1), it is possible to display a high quality image by a stable screen edge detection signal (claim 10).

FIG. 2 is a block diagram showing the construction of a screen edge detection signal generator of an automatic static convergence correction device according to the second embodiment of the present invention (claim 2).

In FIG. 2, reference numeral 4a denotes a first microprocessor unit (hereinafter referred to as MPU-1), which is shown in FIG.
Performs the same function and operation as the MPU4. 4b is a second microprocessor unit (hereinafter referred to as MPU-2),
The counter 1, the data latch 2 and the comparator 3 shown in FIG.
The hardware functions and operations of are performed by software.
In addition, the same reference numerals are given to the blocks and the like having the same configurations as those of the embodiment of FIG.

Next, the operation of FIG. 2 will be described.
2 (4b) has a built-in counter 4b-1 for the horizontal synchronizing signal 10 that is reset (RESET) by the vertical synchronizing signal 11, so that the counter counts the current number of scanning lines 14 in advance, and the MPU- When the number of screen edge scanning lines 13 set within 2 (4b) is reached, a screen edge detection signal 15 is output.

This screen edge detection signal 15 causes the switch 33
Is switched from the current solid line position to the broken line position, and MPU-1
The on-screen reference signal 16 from (4a) is output as valid. It should be noted that the MPU-1 (4a) uses the horizontal pulse 12 and the vertical synchronization signal 11 obtained by delaying the horizontal synchronization signal 10 by the horizontal synchronization signal delay device 12 like the MPU 4 of FIG. create. The following operation is performed by the video switch 8 as described in the conventional example of FIG.
Is mixed with the video signal 21 and output to the CRT 25.

As described above, according to this embodiment, by using the count data obtained by counting the horizontal synchronizing signal itself, the screen edge detection signal can be accurately output even if the number of scanning lines of the horizontal synchronizing signal changes. it can. Furthermore, since the screen edge detection signal is not obtained by a combination circuit of a semi-fixed resistor and a comparator as in the conventional case, it is less affected by temperature change.

Next, in the configuration of FIG. 2, as a sixth embodiment, the MPU-2 (4b) is an MPU (not shown) for controlling the operation of the automatic static convergence correction device.
It can also be used as a device (claim 6).

According to this structure, since the MPU-2 (4b) can be omitted, it is simplified and the cost is reduced.

In the configuration of FIG. 2, as the eighth embodiment, the MPU-2 (4b) which counts the current number of scanning lines 14 from the horizontal synchronizing signal 10 and outputs the screen edge detection signal 15
Is an unillustrated MP that controls the operation of the entire video display device.
It can also be used by U (Claim 8).

This structure also has the same structural effect as that of the sixth embodiment.

In the configuration of FIG. 2, the screen edge detection signal generator of the automatic static convergence correction device shown in FIG. 2 as the tenth embodiment is provided, for example, from the image display screen 9, CRT 25 shown in FIG. By using the image display device, it becomes possible to display a high-quality image by a stable screen edge detection signal (claim 10).

[0043]

As described above, according to the present invention,
By outputting the screen edge detection signal using the count data obtained by counting the horizontal sync signals, the screen edge detection signal can be accurately output. Further, even if the number of scanning lines of the input signal changes, the screen edge detection signal can be easily output to any scanning line position.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a screen edge detection signal generation unit of an automatic static convergence correction device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a screen edge detection signal generation unit of an automatic static convergence correction device in a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional auto static convergence correction device.

FIG. 4 is a circuit diagram showing a configuration of a screen edge detection signal generation unit in FIG.

[Explanation of symbols]

1 ... counter, 2 ... data latch, 3 ... comparator,
4 ... Microprocessor unit (MPU), 4a ... 1st microprocessor unit (MPU-1), 4b ...
Second microprocessor unit (MPU-2), 6
… Horizontal sync signal delay device, 10… Horizontal sync signal, 11…
Vertical sync signal, 12 ... Horizontal pulse, 13,17 ... Screen edge scanning line number, 14 ... Current scanning line number, 15 ... Screen edge detection signal, 16 ... On-screen reference signal, 33 ... Switch.

Claims (10)

[Claims] 1. A current raster position is detected by using an optical sensor installed outside a screen for displaying an image, and a deviation from a preset position is set in a microprocessor unit as a deviation amount of static convergence. In the auto static convergence correction device that performs convergence correction of the electron beam that scans the screen according to the amount, the horizontal sync signal is counted with the vertical sync signal as the clear input, and the current number of scanning lines is output. A counter, a microprocessor unit for writing the number of screen edge scanning lines, which is comparison latch setting data at both ends of the screen from the vertical and horizontal synchronizing signals, in a data latch, and a current number of scanning lines from the counter and the data latch. Comparison of both screen edges Compare with the number of scanning lines at the screen edge which is the latch setting data , And a comparator for outputting a screen edge detection signal when a match,
An automatic static convergence correction device, wherein an on-screen reference signal from the microprocessor unit is validated by the screen edge detection signal. 2. The present raster position is detected by using an optical sensor installed outside the screen for displaying the image, and the deviation from the preset position is set in the microprocessor unit as the deviation amount of the static convergence. In the auto static convergence correction device that performs convergence correction of the electron beam that scans the screen according to the amount by inputting vertical and horizontal synchronization signals and counting the current number of scanning lines from the horizontal synchronization signal. When a preset number of screen edge scanning lines is reached, a second microprocessor unit that outputs a screen edge detection signal and the vertical and horizontal synchronization signals are input, and the on-screen reference signal is enabled by the screen edge detection signal. And a first microprocessor unit for outputting Data tick convergence correction device. 3. The comparator compares the current number of scanning lines from the counter with the number of screen edge scanning lines, which is the comparison latch setting data fixed at both edges of the screen in advance, and outputs a screen edge detection signal. The automatic static convergence correction device according to claim 1, wherein 4. The screen comparator compares the current number of scan lines from the counter with the number of screen edge scan lines, which is comparison latch setting data from both ends of the screen, which is comparison latch setting data from the microprocessor unit. The automatic static convergence correction device according to claim 1, wherein a detection signal is output. 5. The number of screen edge scanning lines, which is comparison latch setting data at both ends of the screen from the microprocessor unit and is input to the data latch, is changed according to the frequency of a horizontal synchronization signal input to the microprocessor unit. The automatic static convergence correction device according to claim 1, wherein 6. The second microprocessor unit that counts the current number of scanning lines and outputs a screen edge detection signal is also used as a microprocessor unit that controls the operation of the auto static convergence correction device. The automatic static convergence correction device according to claim 2. 7. The microprocessor unit for setting the number of screen edge scanning lines, which is the comparison latch setting data for both ends of the screen, is also used as a microprocessor unit for controlling the operation of the auto static convergence correction device. The automatic static convergence correction device according to claim 4. 8. A second microprocessor unit for inputting vertical and horizontal synchronizing signals, counting the current number of scanning lines from the horizontal synchronizing signal, and outputting a screen edge detection signal,
3. The automatic static convergence correction device according to claim 2, wherein the microprocessor unit for controlling the operation of the entire image display device is also used. 9. The microprocessor unit for setting the scanning lines at both ends of the screen, which is the comparison latch setting data at the both ends of the screen, is also used as the microprocessor unit for controlling the operation of the entire image display device.
The described auto static convergence correction device. 10. The image display device according to claim 1 or 2.
An image display device characterized by using the described auto static convergence correction device.