JPH0448891A - Digital convergence correction device - Google Patents

Abstract

PURPOSE:To improve the efficiency of convergence correction by applying connection of red and blue convergence coils in opposite polarity to each other respectively and providing a switch through which a same correction waveform is applied to'' a red signal and a blue signal simultaneously at a same adjustment point. CONSTITUTION:Convergence yokes 17, 18 are connected to drive circuits 15, 16 respectively in opposite polarity to each other. With terminals a, b of an address changeover switch 8 closed, a synchronization address is led simultaneously to a red frame memory 9 and a blue frame memory 10. Then a digital correction data in the frame memories 9, 10 corresponds respectively to an adjustment point being a cross point of cross hatch patterns and read corresponding to raster scan. When a simultaneous write switch 22 is closed, 3-color cross hatch patterns are displayed and two colors (red and green) are adjusted roughly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a digital convergence correction device for a color television receiver.

Flame rice plot twist FIG. 5 is a block diagram of a conventional example.

In Fig. 5, 1 is a phase-locked loop (r
A horizontal blanking signal is input to the horizontal blanking input terminal 2 of the PLL circuit 1, a vertical blanking signal is input to the vertical blanking input terminal 3 of the PLL circuit 1, and the output of the PLL circuit 1 is Outputs the reference clock from the terminal. This reference clock is input to the next stage timing generation circuit 4, and the crosshatch generation circuit 5
It outputs an X row, y column signal (x, y are natural numbers) to the address generating circuit 7, and an address clock signal to the address generating circuit 7. The crosshatch generating circuit 5 outputs a crosshatch signal for displaying a crosshatch pattern W of nine horizontal lines and seven vertical lines within the screen, as shown in FIG. 2, for example. In this case, the convergence adjustment points P are the intersections of the crosshatch pattern W. Address generation circuit 7 outputs a synchronous address to terminal a of address switching circuit 8. The synchronous address is synchronized with horizontal and vertical blanking signals input to the PLL circuit 1. The address switching circuit 8 includes terminals A and C in addition to the terminal A. Switching between terminals a-b and terminal c-b is controlled by an address switching signal output from the control circuit 25. If terminals a-b are currently ON as shown in FIG. 5, the synchronization address is led to the frame memory 31. The digital correction data in the frame memory 31 each corresponds to an adjustment point P which is an intersection of loss hatch patterns as shown in FIG. 2, and is read out one after another as digital correction data in response to raster scanning. The read digital correction data is converted into an analog signal by a D/A conversion circuit 32, smoothed by a low-pass filter (hereinafter referred to as "LPF") 33, and thereafter amplified by a drive stage (not shown). After that, it is fed to the convergence yoke.

The control circuit 25 is a circuit using, for example, a microprocessor, and outputs a control address signal to the terminal C of the address switching circuit 8 and the nonvolatile memory 26. At the same time, it has a bidirectional data bus for frame memory 31 and nonvolatile memory 26. In other words, when terminal c-b of the address switching circuit 8 is turned ON by the address switching signal output from the control circuit 25 to the address switching circuit 8,
The frame memory 31 is now addressed by the control address signal and its contents can be changed through the data bus of the control circuit 25, allowing appropriate convergence correction digital data to be written.

Reference numeral 20 denotes a controller connected to the control circuit 25, and the controller 20 has cursor keys 21 for moving the cursor up, down, left, and right, and for convergence adjustment, green (hereinafter referred to as "G") is fixed and red (hereinafter referred to as "G") is fixed. 1[
) to match G or blue (hereinafter referred to as rB)
A color switching button 23 for selecting one of the adjustments to match G with G, and a mode switching button 24 for selecting either a cursor movement mode for moving the cursor or a convergence adjustment mode for adjusting convergence are provided.

Next, a method for adjusting convergence will be explained. Convergence adjustment can be divided into two ways: fixing G and making R match G, and making B match G. First, select either GR adjustment or CB adjustment using the color switching button 23 of the controller 20. For example, if you select GR adjustment using the color switching button 23, a crosshatch pattern of G and R will be displayed on the screen. . Next, the mode switching button 24 of the controller 20 is used to select either a cursor movement mode in which the cursor key 21 moves the cursor on the display or a convergence adjustment mode in which convergence is adjusted. The cursor movement mode is a mode in which the cursor moves vertically and horizontally on the display by operating the cursor keys 21, and the convergence adjustment mode is a mode in which the cursor moves vertically and horizontally on the display by operating the cursor keys 21, and the convergence adjustment mode is a mode in which the cursor moves vertically and horizontally on the display.
This is a mode in which the coherence is corrected vertically and horizontally by operating the cursor key 21 vertically and horizontally. That is, when the cursor movement mode is first selected with the mode switching button 24 and the cursor key 21 is operated, the cursor moves to the point where correction is desired.

Next, after selecting the adjustment point P as described above, select the convergence adjustment mode with the mode switching button 24, and correct the convergence at the location where the cursor is located by using the up/down/left/right operations of the cursor key 21 to perform crosshatching. This is done by matching R of the pattern with G.

Thereafter, the convergence is corrected in the same way for all the adjustment points P on the screen which are the intersections of the crosshatch patterns, and the convergence correction of G and R is completed.

Next, select another color (in this case, GB) using the color switching button 23, and similarly perform corrections on all adjustment points on the screen. When a series of convergence correction operations are completed, by turning on the controller 20 or a separately provided write switch (not shown), the control circuit 25 outputs an address switching signal to the address switching circuit 8 only during the vertical blanking period. The writing is completed by outputting the terminal c-b so that it is turned ON, and transferring and writing the contents of the frame memo 1731 to the nonvolatile memory 26 via the bidirectional data bus.

In the case of projection television, the convergence deviation is 281°291.3 for each of R, G, and B as shown in Figure 4.
(As shown by le, it becomes larger towards the periphery of the screen, but this is R, G as shown in Figure 3.

This is because when 83 cathode ray tubes 28, 29, and 30 are arranged in the horizontal direction, the angles relative to the projection screen 27 are different, so that the projected raster will be misaligned as shown in FIG. This positional shift is in opposite directions in the R and B directions, centering on the G raster scan 29f in which the cathode ray tube is arranged in the center.

In the above-mentioned conventional convergence correction device, in areas where the amount of correction is large, such as at the periphery of the screen, the absolute amount of correction to make R and B match G is approximately equal, only that the direction of correction is opposite. However, convergence correction is performed separately and independently for each method, which poses a problem in that adjustment is time-consuming and complicated.

In order to solve the above problem, the present invention connects the polarities of the red and blue convergence yokes in opposite directions, and installs a switch that simultaneously applies the same correction waveform to red and blue at the same adjustment point. It is configured so that coarse adjustments can be easily made, and when coarse adjustments are made to the two colors mentioned above at the same time, all three colors are displayed on the screen, and when fine adjustments are made for each color, green and the color to be adjusted are displayed. Make it.

Effect When you turn on the switch that corrects two colors at the same time, RlG, B
A three-color crosshatch pattern is displayed at the same time, R and B
A correction signal having the same absolute value and opposite polarity is added to R and B, and coarse adjustment is performed simultaneously for the two colors so that R and B match G. Moreover, when the switch is changed, a crosshatch pattern of either R or B and two colors of G is displayed, and R or B can be finely adjusted for each color.

Embodiment FIG. 1 is a block diagram of the present invention. Portions corresponding to the conventional example shown in FIG. 5 are given the same reference numerals and explanations will be omitted.

In FIG. 1, 6 is a display color switching circuit that switches the display color of the crosshatch pattern from the crosshatch generating circuit 5 in response to a display color switching signal from the control circuit 25;
and 10 are red and blue frame memories that store red and blue digital correction data, respectively, and the frame memories 9 and 10 receive a synchronization address from the address generation circuit 7 or a synchronization address from the control circuit 25 from the address switching circuit 8. Control address signals are selectively provided. In addition, the frame memories 9 and 10, the control circuit 25, and the nonvolatile memory 2
A data bus is provided between the 6 and 6. 11 and 1
2 are a red/A conversion circuit and a blue/A conversion circuit that D/A convert the output data of the frame memories 9 and 10, respectively, and 13 and 14 are derived from the D/A conversion circuits 13 and 14, respectively. LPF that smoothes the analog signal that is
15 and 16 are drive circuits for the red convergence yoke 17 and the blue convergence yoke 18, respectively, and the convergence yokes 17 and 18 are the drive circuits for the respective drive circuits 1.
5 and 16 with opposite polarity. 19 is a control signal from the control circuit 25, that is, a chip selection signal τ and Ir for individually selecting the frame memories 9 and 10;
In response to the chip selection signal τ-ding-OTH that simultaneously selects the frame memories 9 and 10, m and τ-ding-- are sent to the red frame memory 9 and the blue frame memory 10 with frame memory selection signals that select the frame memories, respectively. This is a decoding circuit that supplies 22 is a simultaneous write switch for convergence correction that simultaneously makes red and blue match green.

Since the embodiment of the present invention has the above configuration, when the simultaneous write switch 22 provided in the controller 20 is pressed, a display color switching signal is output from the control circuit 25 to the display color switching circuit 6, and the color switching button 23 is switched to which adjustment state. However, a crosshatch pattern of 83 colors, including R and G, is displayed on the display device. At the same time, a control signal is sent from the control circuit 25 to
At r, TN (chip select 2 colors) becomes "Low" and is output to the decoding circuit 19. Decoding circuit 19
Here, we simply use two negative logic ORs (if one of the inputs becomes "LoW", the output becomes "Low") and connect the control signal '?ff7N to one input of each. However, when ffi becomes “Low” with this control signal, the chip IV (chip select R memory) control signal 8 is activated as a control signal.
Ding Ding V (chip select B memory) is “Low”
”.Currently, as shown in FIG. 1, if terminals a and b of the address switching circuit 8 are turned on,
The synchronization address is simultaneously led to the red frame memory 9 and the blue frame memory 10. The digital correction data in each of the frame memories 9 and 10 corresponds to adjustment points that are intersections of loss hatch patterns, as shown in FIG. 2, and is read out in response to raster scanning. Further, when the terminal c-b of the address switching circuit 8 is turned on, the red frame memory 9. The and blue frame memories 10 are each addressed by a control address signal, and data can be written through the data bus of the control circuit 25. Now, when the control signal -03 is set to ``Low'', both TT and I are set to ``Low'', and the red frame memory 9 and blue frame memo January 0 The same data is written to both. The same written data is read out in accordance with the raster scan, converted into analog signals by the red/A conversion circuit 11 and the blue/A conversion circuit 12, and then sent to the red LPF.
(Low pass filter) 13. Each is smoothed by the blue LPF 14.

After being smoothed, it is amplified by drive circuits I5 and 16 for each color, and then supplied to each convergence yoke 17.1B (hereinafter referred to as rCY).
If the red and blue convergence yokes 17 and 18 are connected with the same polarity, even if the same data is supplied to CY in the same way in R and B, the convergence of one R will match, but the other 177B will remain in the current state. The convergence will shift further. Therefore, by reversing the polarity of CY of B, the same data can be written simultaneously. This is because, as is clear from Figure 4, at the same adjustment point, the convergence shift of R and B is almost symmetrical with respect to G. When the switch 22 is turned on, a three-color crosshatch pattern is displayed, and rough adjustments can be made for two colors, red and green, at the same time. When the simultaneous write switch 22 is turned off, the control signal S-100T from the control circuit 25 becomes "High", and the control signal S-100T and the control signal 8-D2V do not become low active at the same time. , the signal corresponding to the color change button 23, for example, if R is selected, the control signal 'f' is selected.
Only f (chip select R) becomes "Low", and in the decoding circuit 19, only the control signal 8-cho-cho V becomes "LOW", and the red frame memory 9 can write data from the data bus. Ding Ding V is “Hi”
gh'' and does not become low active, the data bus of the blue frame memory 10 enters a high impedance state and no data is written.In other words, only one color, red, can be finely adjusted.Also, R is adjusted. In this state, only G and R display signals are output to the display color switching circuit 6.
Only the R two-color crosshatch pattern will be displayed. The convergence correction that makes blue match green can be performed in the same way as the convergence correction that makes blue match green.

Since the present invention has the above-described configuration, it is possible to perform coarse convergence adjustment for two colors at the same time, and it is possible to improve the efficiency of convergence correction.

Also, during coarse adjustment, the crosshatch pattern of three colors R, G, and B is displayed simultaneously, and during fine adjustment, the crosshatch pattern of R and the color to be adjusted is displayed, so it is easy to see which state of adjustment is being performed. can be judged.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a diagram showing a crosshatch pattern, FIG. 3 is a diagram showing the principle of a projection type projector, and FIG. 4 is a diagram showing a convergence shift of the projector. FIG. 5 is a block diagram of a conventional example. 5-Crosshatch generation circuit. 6-Display color switching circuit, 9-Red frame memory. 10-・Blue frame memory. 17- Red convergence yoke. 18- Blue convergence yoke. 22-Simultaneous write switch.

Claims (2)

[Claims] (1) On the screen of a raster scan color display device, each intersection of a cross-hatch pattern that divides the horizontal direction into x and the vertical direction into y is set as a digital convergence correction point, and the digital correction amount corresponding to each correction point is stored. In a digital convergence correction device that has a frame memory that reads out the digital correction amount of the frame memory in synchronization with the deflection timing of a color display device to correct convergence, the red and blue convergence yokes are connected in opposite polarities to the red and blue convergence yokes. A digital convergence correction device characterized in that a blue convergence yoke is provided with a switch that applies the same correction waveform at the same adjustment point at the same time, so that coarse adjustment of two colors, red and blue, can be performed simultaneously. (2) On the screen of a raster scan type color display device, each intersection of a crosshatch pattern that divides the horizontal direction into x and the vertical direction into y is used as a digital convergence correction point, and the digital correction amount corresponding to each correction point is stored. In a digital convergence correction device that has a frame memory that reads out the digital correction amount of the frame memory in synchronization with the deflection timing of a color display device to correct convergence, the red and blue convergence yokes are connected in opposite polarities to the red and blue convergence yokes. A changeover switch is provided to apply the same correction waveform to the blue convergence yoke at the same adjustment point at the same time, or to apply the correction waveform to either the red or green convergence yoke sequentially.
During coarse adjustment, in which colors are adjusted at the same time, three color adjustment patterns are displayed on the screen, and during fine adjustment, in which two colors, red and blue, are adjusted separately, adjustment patterns for green and the color to be adjusted are displayed on the screen. A digital convergence correction device characterized by being designed to project.