JPH0349494A - Digital convergence device - Google Patents

Abstract

PURPOSE:To adjust the convergence deviation of all scanning lines of a screen with less memory capacity quickly with high accuracy by assigning a stack area, a working area used for a CPU, a digital convergence control data used for a control section to a one frame random access memory storing the correction of all scanning lines. CONSTITUTION:A nonvolatile one frame memory 4 storing the correction of all adjustment points and a one frame random access memory 3 storing the correction corresponding to all scanning lines are provided and a stack area, a working area used for a CPU 2, a digital convergence control data area are assigned to an idle area of a one frame random access memory 3. In this case, the adjustment point is independent and optional correction is attained. Thus, the convergence deviation is adjusted with less memory capacity in comparison with a conventional system with high a accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a digital convergence device that can quickly and accurately adjust convergence correction in a color television receiver.

2. Description of the Related Art As is well known, a shadow mask type color cathode ray tube (hereinafter abbreviated as CRT) used in general color television receivers has three electron guns: red, green, and blue. However, it is structurally impossible to arrange all of these multiple electron guns on the central axis of the CRT, so they are mounted a little away from the central axis and slightly tilted inward with respect to the central axis. Therefore, on the screen on this central axis, each electron beam converges at the shadow mask and simultaneously emits red, green, and blue fluorescent dots through the same hole, creating a convergence state. ．． However, since the radius of curvature of the shadow mask is larger than the distance from the center of deflection to the center of the roadway mask, CR
At locations other than the central axis of T, the three electron beams converge in front of the shadow mask. Therefore, the three electron beams cannot pass through the same hole at the same time, and the color shift, or convergence shift, in the re-imaged image increases as it moves away from the center of the screen. In order to prevent such problems, it is necessary to perform convergence correction so that the three electron beams converge at the shadow mask over the entire screen.

In addition, in projection-type color television receivers that use three CRTs that emit three primary colors to project enlarged images onto a screen, color shift occurs on the screen because the incident angle of the CRT to the screen differs for each CRT. ．． For the superposition of these three primary colors, so-called convergence, a method is generally adopted in which a convergence correction waveform is obtained in an analog manner using passive elements such as LSC and R, rather than a horizontal flyback pulse and a vertical deflection waveform. However, there is a problem with the degree of convergence. In contrast, a method of digitally performing convergence correction has been proposed as a method for achieving more accurate convergence. The concept is to project a convergence correction pattern such as a crosshatch on the screen, digitally write the convergence correction amount data for each intersection in one frame memory, and synchronize this information with horizontal and vertical scanning. It reads out data, performs D/A conversion, amplification processing, and performs convergence correction. An example of the above digital convergence correction will be explained below with reference to the drawings. 2UjJ is a diagram showing the projected state of the crosshatch which is the convergence adjustment signal, and FIG. 3 is a diagram of the digital convergence device. As shown in FIG. 2, a crosshatch 18 indicating adjustment points in, for example, 9 columns in the horizontal direction and 7 rows in the vertical direction is displayed on the screen from the convergence adjustment signal output terminal 11 of the control section 1. The intersection of this crosshatch 18 becomes the adjustment point. Note that the control unit 1 receives signals input from the horizontal synchronization signal input terminal 12, vertical synchronization signal input terminal 13, and clock input terminal 14, and digital convergence control data from the data buffer random access memory 5 to the CPU 2,
It generates a control signal l4 for controlling the nonvolatile l-frame memory 4, the one-frame random access memory 3, the data buffer random access memory 5, etc., controls the digital convergence device, outputs a pattern signal for convergence correction, and controls the control panel. 6
and interfaces with CPU2. First, convergence adjustment will be explained.

When you select the adjustment point on the control panel 6 in Figure 3,
PU2 obtains the cursor address of the adjustment point. At this time, the addresses of the nonvolatile one-frame memory 4 and data buffer random access memory 5 are also determined. In addition,
The data buffer random access memory 5 is allocated with a stack area and a working area used by the CPU 2, in addition to an area for storing digital convergence control data and correction amounts for all adjustment points of the crosshatch l8. After the above operation, the control section 1 displays the cursor 19 at the corresponding adjustment point on the screen.

Next, input the color you want to correct from the control panel 6,
Look at the cursor 19 on the screen indicating the selected adjustment point, perform convergence adjustment using the adjustment keys on the control panel 6, and write the desired correction amount to the specified address in the data buffer random access memory 5.
The only correction amounts written in the data buffer random access memory 5 are those at positions corresponding to the adjustment points shown in FIG. Therefore, the amount of correction for each of the M scanning lines included between adjustment points in the vertical direction must be determined by interpolation. For example, when adjustment point B is selected with the cursor 19 as shown in FIG. Using the correction amount at point C, the correction amount for each scanning line included between adjustment point A and adjustment point B and between adjustment point B and adjustment point C is determined by approximate calculation by CPU 2 as described later. By writing to the corresponding address of the 1-frame random access memory 3, the convergence correction amount of the scanning line other than the adjustment point can be obtained.After a certain period of time has elapsed after the adjustment key operation is completed, the above correction amount is stored in the non-volatile 1. Write to frame memory 4. Repeat the above operations sequentially for all adjustment points. Hereafter, the same process is performed for other colors. By doing the above, it is possible to perform convergence adjustment for the entire screen.

Next, the above approximate calculation will be explained. As shown in Fig. 2, for example, the change for each scanning line between adjustment points is determined from the correction i1a of adjustment point A and the correction amount b of adjustment point B, and this change and the correction amount b of adjustment point B are added. In addition, calculate the amount of correction for each scanning line. In other words, n lines above adjustment point B (n
≦M) is approximated by the following equation.

M+1 Incidentally, during the convergence adjustment operation, the correction amount for each adjustment point is written into the nonvolatile l-frame memory 4, and this is to back up the correction amount for each adjustment point. When the digital convergence device is powered off, the data buffer random access memory 5
, 1. The correction amount written in the frame random access memory 3 disappears. However, the written correction amounts for each adjustment point are recorded in the nonvolatile l-frame memory 4 as they are. Therefore, when the power is turned on, the correction amount for each adjustment point written in the nonvolatile l-frame memory 4 is written to the data buffer random access memory 5, and the data buffer random access memory 5
By interpolating the correction amount of each adjustment point written in the CPU 2 and writing the correction amount for each scanning line into the l-frame random access memory 3, it is possible to eliminate the trouble of re-adjusting every time the power is turned on. can. Next, we will explain full-screen convergence correction. As mentioned above,
The correction amount for each scanning line of the entire screen is written in the l-frame random access memory 3. This correction amount is read out using an address signal synchronized with the vertical synchronization signal and the horizontal synchronization signal output from the control unit l, and the D/A converter 7
Convert it to an analog signal with a low-pass filter (L P
F) The signal is smoothed by 8, amplified by amplifier 9, and then supplied from a convergence correction signal output terminal 10 to a convergence coil (not shown). As described above, convergence correction can be performed for the entire screen. With the digital convergence device described above, the adjustment points can be adjusted independently and as desired, so convergence correction can be performed with high accuracy. Problems to be Solved by the Invention Storing the correction amounts for all adjustment points requires a considerable amount of memory capacity. However, in the above configuration, the correction amounts for all adjustment points are written to both the non-volatile 1-frame memory 4 and the data buffer random access memory 5, which causes the problem that the memory is not used effectively. I had it. In view of the above-mentioned problems, the present invention has been developed to
The present invention provides a digital convergence device that enables effective use of memory by allocating the U working area, stack area, and digital convergence control data area to the free memory M area of one frame random access memory. Means for Solving tlB In order to solve the above problems, the digital convergence device of the present invention has a nonvolatile one-frame memory that stores correction amounts for all adjustment points, and a non-volatile one-frame memory that stores correction amounts corresponding to all scanning lines. The system is equipped with a frame random access memory, and the CPυ stand area, working area, and digital convergence control data area are allocated to the free area of the frame random access memory. According to the present invention, it is possible to adjust the convergence shift with high accuracy on all screens, just like the conventional system, with a smaller memory capacity than the conventional system. Embodiment Hereinafter, a digital convergence device according to an embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram of a digital convergence device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a state in which a crosshatch, which is a convergence adjustment signal, is displayed. As shown in FIG. 2, a crosshatch l8 indicating adjustment points in, for example, 9 columns in the horizontal direction and 7 rows in the vertical direction is displayed on the screen from the convergence adjustment signal output terminal 11 of the control unit l shown in FIG. do. The intersection point of this crosshatch for 1 day becomes the adjustment point. Note that the control unit 1 receives signals input from the horizontal synchronization signal input terminal 12, the vertical synchronization signal input terminal 13, and the clock input terminal 14, and the random access memory 5 for data buffer.
CPU2 from the digital convergence control data of
, generates control signals for controlling the nonvolatile 1-frame memory 4, 1-frame random access memory 3, etc., controls the digital convergence device, outputs a pattern signal for convergence correction, and interfaces the control panel 6 and the CPU 2. There is. First, convergence adjustment will be explained.

When you select the adjustment point on the control panel 6 in Figure 1,
PU2 obtains the cursor address of the adjustment point. At this time, the addresses of the nonvolatile 1-frame memory 4 and the 1-frame random access memory 3 are also determined. Furthermore, data for digital convergence control, a stack area used by the CPU 2, and a working area are allocated to the one-frame random access memory 3. After the above operation, the control unit 1 displays a cursor l9 at the corresponding adjustment point on the screen. Next, input the color you want to correct from the control panel 6, look at the cursor l9 on the screen that indicates the selected adjustment point, and perform the convergence adjustment using the adjustment keys on the control panel 6 to obtain the desired correction amount by 1 frame random access. Write to the specified address in memory 3. At this point, only the correction amount at the position corresponding to the adjustment point shown in FIG. 2 is written in the one-frame random access memory 3. Therefore, the amount of correction for each of the M scanning lines included between adjustment points in the vertical direction must be determined by interpolation. For example, if adjustment point B is selected with the cursor l9 as shown in FIG. Using the correction amount of , the correction amount of the scanning line between adjustment point A and adjustment point B and between adjustment point B and adjustment point C is calculated as C as described later.
By obtaining it by approximate calculation in PU2 and writing it to the corresponding address of one frame random access memory 3,
You can find the convergence correction amount for scanning lines other than the adjustment points. When a certain period of time has elapsed after the completion of the iIl adjustment key operation, the commanded correction amount is written into the non-volatile 1-frame memory 4. Repeat the above operations sequentially for all adjustment points. Below, do the same for other colors. By doing the above, you can adjust the convergence of the entire screen. Next, the above approximate calculation will be explained. As shown in Fig. 2, for example, the change for each scanning line between the adjustment points is calculated from the correction amount a of adjustment point A and the correction 1b of adjustment point B, and this change and the correction amount b of the second line are calculated. Add them together to find the amount of correction for each scanning line. That is, the correction amount α over n lines (n≦M) from the second line is approximated by the following equation. a-b α-rich Xn+b M+1 Incidentally, during the convergence adjustment operation, the correction amount for each adjustment point is written into the non-volatile 1-frame memory 4, and this is to back up the correction amount for each adjustment point. When the power of the digital convergence device is turned off, the correction amount written in the 1-frame random access memory 3 disappears. However, the written correction amount for each adjustment point is stored in the nonvolatile one-frame memory 4 as is. Therefore, when the power is turned on, the CPU 2 interpolates the correction amount for each adjustment point stored in the nonvolatile l-frame memory 4 and writes the correction amount for each scanning line to the 1-frame random access memory 3. By performing this process, you can eliminate the trouble of re-adjusting each time you turn on the power. Next, we will explain full-screen convergence correction.
As mentioned above, the correction amount for each scanning line of the entire screen is written in the 1-frame random access memory 3. This correction amount is read out using an address signal synchronized with a vertical synchronization signal and a horizontal synchronization signal output from the control unit 1,
The signal is converted into an analog signal by a D/A converter 7, smoothed by a low-pass filter (LPF) 8, amplified by an amplifier 9, and then supplied to a convergence coil (not shown) from a convergence correction signal output terminal 1O. As described above, convergence correction can be performed for the entire screen. As described above, this Yokokai can perform the same interpolation operations as conventional methods with less memory capacity than conventional methods, and can adjust convergence shifts quickly and accurately. Effects of the Invention As described above, the present invention has a stack area and a working area used by the CPU, and storage of digital convergence control data used by the control unit in the 1-frame random access memory that stores the correction amount of all scanning lines. By allocating areas, it is possible to quickly and accurately adjust the convergence shift of all scan lines on the screen using the same method as before, even though the memory capacity is smaller than before.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a digital convergence device according to an embodiment of the present invention, FIG. 2 is a diagram showing a state in which a crosshatch, which is a convergence adjustment signal, is projected, and FIG. 3 is a block diagram of a conventional digital convergence device. It is.

Claims (1)

[Claims] means for generating a convergence correction pattern so that the screen of a color television receiver has a plurality of convergence adjustment points in the horizontal and vertical directions; means for inputting the correction amount of the specified adjustment point into the frame memory, means for writing the correction amount of the specified adjustment point into the corresponding address of the one frame random access memory, and means for writing the correction amount corresponding to all the scanning lines between the two adjustment points to the
Means for calculating by approximate calculation based on the correction amount of the adjustment point read from the frame random access memory and writing it to the address corresponding to the scanning line of the 1-frame random access memory, and the correction amount of the adjustment point written in the 1-frame random access memory. means for writing the correction amount to the address corresponding to the adjustment point of the non-volatile 1-frame memory, and when an operation to change the correction amount of the specified adjustment point is performed, the correction amount of the address of the 1-frame random access memory corresponding to the adjustment point is written. Rewrite, calculate the correction amount corresponding to all the scanning lines between the adjustment point and the adjustment point in the vertical direction by approximate calculation, write it to the corresponding address of the 1-frame random access memory, and change the correction amount of the specified adjustment point. When the operation is completed, the correction amount written to the address corresponding to the adjustment point in the 1-frame random access memory is written to the corresponding address in the non-volatile 1-frame memory, thereby correcting the convergence shift of all scanning lines on the screen. A digital convergence device characterized by adjusting.