JPH04282994A - Digital convergence device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for correcting convergence in a color television receiver, and more particularly to a highly accurate digital convergence device that does not cause color shift due to calculation errors.

0002

[Prior Art] Generally, in a projection type color receiver that uses three projection tubes emitting three primary colors to project enlarged images onto a screen, the angle of incidence of the projection tubes with respect to the screen is different for each projection tube. Therefore, color shift occurs on the screen. The superposition of these three primary colors, so-called convergence, is achieved by creating an analog convergence correction waveform in synchronization with the horizontal and vertical scanning cycles, and adjusting the size and shape of this waveform. However, there is a problem with convergence accuracy. Therefore, as a method that can handle various signals and has high convergence accuracy, for example,
A digital convergence device has been proposed in Japanese Patent No. 130288.

The conventional digital convergence device will be explained below. FIG. 9 shows a block diagram of a conventional digital convergence device, in which a convergence correction pattern such as a crosshatch pattern is projected on the screen, and the data of the convergence correction amount for each adjustment point is digitally stored in the frame memory. This data is read out, D/A converted, and convergence correction is performed.

FIG. 9 shows a block diagram of a conventional digital convergence device. In the figure, 1 is a synchronization signal input terminal, 2 is an address generator, 3 is a pattern generator, 4 is a frame memory, 5 is a vertical interpolator, 6 is a D/A converter, and 7
8 is a low pass filter (LPF), 8 is a control panel, and 9 is a data control section. A synchronizing signal of horizontal and vertical periodic pulses synchronized with the deflection current period is applied to an input terminal 1, and this signal is supplied to an address generator 2 to generate various address signals. The pattern generator 3 is driven using pulses from the address controller 2 to project a crosshatch pattern on the projection screen. On the other hand, by using the address keys on the control panel 8, a cross point at a position requiring convergence correction is specified, and the position address is set in the address control section 2. Next, using a data write key for the color to be corrected, for example, red provided on the control panel 12, the correction amount is written into the frame memory 4 through the data control section 9 while looking at the screen, and the correction is performed. Normally, switching control is performed so that writing to the one-frame memory 4 is performed during the blanking period of the video signal. Therefore, reading is not impaired. Similar operations are performed at each adjustment point as described above.

Next, the frame memory 5 is read out by the address control section 2 in correspondence with each adjustment point position on the screen. Since the frame memory 5 stores only correction data for locations corresponding to each adjustment point, the vertical interpolation section 5 performs interpolation calculations between adjustment points in the vertical direction. A signal obtained by converting the output of the vertical interpolation unit 5 into an analog quantity by a D/A converter 6 is obtained. The signal between adjustment points in the horizontal direction is filtered by a low-pass filter (L
After smoothing with PF7 and amplifying with a convergence output amplification section, it is supplied to a convergence yoke.

As described above, since independent correction can be performed for each adjustment point, convergence correction can be performed with high accuracy.

[0007]

[Problems to be Solved by the Invention] However, in the digital convergence device configured as described above, since the approximation calculation for vertical interpolation between adjustment points differs depending on the correction waveform, errors occur between adjustment points and color There was a problem in that misalignment occurred.

[0008] As a means to solve the above problem, there is a combined digital and analog system, but this method has the problem of increasing the circuit scale.

In view of this, the present invention reduces the calculation error in an all-digital correction system by time-divisionally processing correction data for each adjustment point and the entire screen, writing it into memory, and performing optimal interpolation calculation processing for each mode. It is an object of the present invention to provide a digital convergence device that can reduce color shift caused by color shift.

0010

[Means for Solving the Problems] The invention as set forth in claims 1 and 2 provides a storage means for digitally time-divisionally processing and storing correction data for each adjustment point and the entire screen; The image forming apparatus includes a first calculation means for interpolating, a second calculation means for interpolating the correction data of the entire screen, and an addition means for adding the outputs from each calculation means.

Furthermore, in the linear approximation interpolation of the correction data between each adjustment point, the correction data of the entire screen is provided with means for performing curve approximation calculation from a straight line in accordance with the operation of the correction system.

The invention as set forth in claim 3 provides a storage means for digitally time-divisionally processing and storing correction data of the main and sub adjustment points in which the adjustment points are arranged alternately; It is provided with calculation means for interpolating data and addition means for adding each output from the calculation means.

[0013]

According to the invention as set forth in claims 1 and 2, the correction data for each adjustment point and the entire screen is time-divisionally processed and written into the memory, and the optimal interpolation calculation processing for each mode is performed.
Color shift due to calculation errors in interpolation calculations can be eliminated, and highly accurate correction can be achieved.

According to the third aspect of the invention, the correction data of the main and sub adjustment points in which the adjustment points are arranged alternately is subjected to time division processing, and the outputs of the interpolation calculations are added to create the correction data. As a result, calculation errors between adjustment points can be significantly improved, and highly accurate correction can be achieved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 5 show a block diagram, a display screen diagram, and an operation waveform diagram of a digital convergence device according to a first embodiment of the present invention. In FIG. 1, 12 is an address control unit for controlling reading and writing of memory for time-series processing, 19 is a time-series processing data control unit for writing data by time-series processing, and 16 is a linear approximation. 55 is a calculation control unit 1 for controlling various interpolation calculations such as curve approximation, etc.
Vertical interpolation units 14 and 15 are sample-hold (S/H) circuits for extracting time-series processed correction data. Figure 2 shows an operating waveform diagram. Note that in this figure, components that operate in the same manner as in the conventional system shown in FIG.

The operation of the digital convergence device of this embodiment constructed as described above will be explained below. A synchronization signal is input to the input terminal 1, and the address control section 12 generates various address signals for controlling the frame memory 4 in a time-series manner.The pattern generation section 3 generates various address signals as shown in the display screen diagram of FIG. For example, a crosshatch pattern of 11 horizontal rows and 7 vertical columns is generated and displayed on the screen. In the frame memory 4, data on intersections of crosshatch signals and data for correcting the entire screen are stored in time series via a time series processing data control unit 19. The data from the frame memory 4 is transferred to the vertical interpolation section 55.
The correction data corresponding to each scanning line between the adjustment points that is supplied to the frame memory 4 and not stored in the frame memory 4 is created. Control signals for various correction modes from the control panel 8 are supplied to the calculation control section 16 to obtain approximate calculation processing for each adjustment point and the entire screen, and this control signal is supplied to the vertical interpolation section 55. The vertical interpolation unit 55 processes the 2
In the system data system, when interpolating between each adjustment point, use linear approximation, for example, use linear approximation when the corrected waveform is a sawtooth wave during full-screen correction, or use curve approximation when it is a parabolic wave to perform data interpolation. ing. The calculated data from the vertical interpolation section 45 is converted into an analog quantity by the D/A conversion circuit 6 to create a correction waveform. The time-divisionally processed analog waveform from the D/A conversion circuit 46 is supplied to two sample holds (S/H) with different sampling periods, and a point correction signal created by interpolating data from each adjustment point is supplied to two sample holds (S/H) with different sampling periods. Dynamic correction data is created by performing data interpolation from the entire screen, and after adding both output signals, it is supplied to the LPF 7, where correction data is smoothed in the horizontal direction. The smoothed data from the LPF 7 is supplied to a current amplification circuit for driving the convergence yoke, where the current is amplified.

Next, in order to explain in detail the reason why the data interpolation system differs depending on the correction system and its operation, we will explain the relationship between the correction changes caused by the correction waveform in FIG. 2 and the movement on the screen, and the interpolation calculation diagram in FIG. 3. Use. In FIG. 2, for example, if the correction waveform shown in (1) is a vertical sawtooth wave with a 1V (vertical scanning) period, when this correction waveform is applied to the vertical convergence coil, amplitude correction in the vertical direction is performed,
When added to the horizontal convergence coil, perform vertical line orthogonal correction. Also, as shown in (4), the correction wave is 1H (
In the case of a horizontal parabolic wave with a period (horizontal scanning), when this correction wave is applied to the vertical convergence coil, it corrects the bending of the horizontal line, and when it is applied to the horizontal convergence coil, it corrects the linearity in the horizontal direction.

As mentioned above, the correction waveform is basically as shown in FIG.
As shown in (a) and (b), the basic waveforms can be classified into parabolic waves and sawtooth waves, where sawtooth waves are obtained by interpolation calculations using linear approximation, and parabolic waves are obtained by interpolation calculations using curved approximation. In the case of convergence correction, Figure 2
Since the correction is performed using a correction waveform in which various correction waves are mixed as shown in FIG. 1, the interpolation calculation becomes very complicated. Figure 3
When adjustment points S1 to S9 shown in (c) exist, FIG.
Between the adjustment points S2 and S3 shown in d), a calculation error ΔD occurs depending on the calculation method, resulting in color misregistration. Therefore, in the present invention, interpolation calculations suitable for the corrected waveform are performed.

Next, various interpolation calculation tables shown in FIG. 4 will be used to explain in detail the method of controlling interpolation calculations. Correction modes can be classified into full screen and point correction modes. Interpolation calculations are performed by linear approximation when the correction waveform in full screen mode is a sawtooth wave, and by curve approximation when it is a parabolic wave. Furthermore, when creating an arbitrary correction waveform in point correction mode, linear approximation is used. Note that the interpolation calculation is controlled by the calculation control section 16 in accordance with the correction mode from the control panel 8 in FIG.

Next, the operation waveform diagram of FIG. 5 will be used to explain the time series processing in detail. In the same figure (a), D of Figure 1 is shown.
It shows digital data inputted to the /A converter 6 and subjected to time series processing, in which point and full screen correction data are written alternately. The output from the D/A converter 6 is shown in (b), and is converted into an analog signal in which point and full screen correction data are multiplexed. The sample and hold pulses input to the S/Hs 14 and 15 in FIG.
) Correction data for performing point correction is output, and correction data for performing correction of the entire screen is output in (f). As shown in FIG. 1, after adding each correction data from the S/Hs 14 and 15, final correction data is created through the LPF 7.

As described above, according to the present embodiment, the correction data for each adjustment point and the entire screen is time-divisionally processed and written into the memory, and the optimal interpolation calculation processing for each mode is performed. Color misalignment caused by calculation errors can be eliminated and highly accurate correction can be achieved.

FIGS. 6 to 8 show a second embodiment of the present invention. First, the configuration differs from that of the embodiment in that sub-master convergence adjustment points are generated alternately and time-division processing is performed to improve correction accuracy. In FIG. 6, reference numeral 29 denotes a time-series processing data control unit for writing data by time-series processing of main and sub-adjustment points;
5 is a vertical interpolation unit for interpolating between vertical adjustment points. In FIG. 6, components that perform the same operations as those in the first embodiment are designated by the same numerals and their explanations will be omitted.

The operation waveform diagram of FIG. 7 will be used to explain the operation of the digital convergence device of this embodiment constructed as described above. As shown in the screen diagram of Figure 6, the main and sub adjustment points are arranged alternately in each direction, and the data processing system processes the correction data of the main adjustment points and the correction data of the sub adjustment points in a time-sharing manner. . Figure 6 (a)
The figure shows time-series processed digital data input to the D/A converter 6, in which correction data for main adjustment points and sub-adjustment points are written alternately. The output from the D/A converter 6 (
As shown in b), the correction data of the main and sub adjustment points are converted into analog signals that are alternately multiplexed. S/H14 and 15 in Figure 6
The sample and hold pulses input to the same figure (c) and (
The correction data shown in (d) is sampled and held at this timing, and the correction data for correcting the main adjustment point is shown in (e).
In (f), correction data for correcting the sub-adjustment points is output. As shown in FIG. 1, after adding each correction data from the S/Hs 14 and 15, final correction data is created through the LPF 7.

Next, the operation waveform diagram of FIG. 8 will be used to explain in detail the method of controlling interpolation calculations corresponding to the main and sub adjustment points. The correction data of the main adjustment point shown in (a) of the same figure and (
By adding the correction data of the sub-adjustment points shown in b), the comprehensive correction data shown in (c) is created. The control signal from the time series processing data control section 29 in FIG. 6 is supplied to the vertical interpolation section 25, which performs interpolation calculations corresponding to the main and sub adjustment points. For example, if you want to create full-screen correction data by rewriting the correction data of the main adjustment point, the old correction data of the sub-adjustment point that was previously written will also be automatically updated in accordance with the new correction data of the main adjustment point. Performing data conversion. This means can be realized by converting the correction data at the sub-adjustment points in accordance with the amount of change in the correction data at the main adjustment points, or by writing the same data. Therefore, by simply writing the correction data for only the main adjustment points, as shown in FIG. 3(d), it is possible to automatically create correction data for the entire screen as shown in FIG. 3(e).

As described above, according to this embodiment, the correction data of the main and sub adjustment points in which the adjustment points are arranged alternately is subjected to time division processing, and the outputs of the interpolation calculations are added to create correction data. As a result, calculation errors between adjustment points can be significantly improved, highly accurate correction can be performed, and adjustment time can be significantly shortened.

In the first and second embodiments, a projection type color receiver has been described for ease of understanding, but it goes without saying that the invention is also effective for a shadow mask type direct view receiver. .

In addition, in the first and second embodiments, the interpolation calculation means is explained as a calculation method using a curved line approximation between two points, but it is also possible to use a calculation method using a curved line approximation between three points. Needless to say.

Furthermore, in the first and second embodiments, a method of correcting color shift using time-divisionally processed correction data has been described, but it is also possible to use this method in common with other corrections such as focus and uniformity. Needless to say.

Furthermore, in the first embodiment, the case where the correction data for the entire screen and the correction data for point correction are processed in a time-sharing manner has been described, but the time-sharing processing may also be performed by interpolation calculation means for linear approximation or curve approximation. Needless to say.

Furthermore, in the second embodiment, data conversion and writing of the same data have been described as a method for calculating sub-adjustment points from correction data of main adjustment points, but other calculations may be performed. Needless to say.

[0031]

As described above, according to the present invention as set forth in claims 1 and 2, the correction data for each adjustment point and the entire screen is time-divisionally processed and written into the memory, and the optimum interpolation for each mode is performed. By performing arithmetic processing, color shift due to calculation errors in interpolation calculation can be eliminated and highly accurate correction can be realized.

According to the third aspect of the present invention, the correction data of the main and sub adjustment points in which the adjustment points are arranged alternately is subjected to time division processing, and the outputs of the interpolation calculations are added to create the correction data. By doing so, calculation errors between adjustment points can be significantly improved, and highly accurate correction can be performed. Furthermore, since it is possible to correct the entire screen by inputting data only at the main adjustment points, the adjustment time can be significantly shortened, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1: Digital converter in one embodiment of the present invention.
FIG. 2 is a block diagram of the zens device.

FIG. 2 is a display screen diagram for explaining the operation of the embodiment.

FIG. 3 is an operation waveform diagram of the same embodiment.

FIG. 4 is an operational diagram of the same embodiment.

FIG. 5 is an operation waveform diagram of the same embodiment.

FIG. 6 is a block diagram of a digital convergence device according to a second embodiment of the present invention.

FIG. 7 is an operation waveform diagram for explaining the operation of the same embodiment.

FIG. 8 is an operation waveform diagram of the same embodiment.

FIG. 9 is a block diagram of a conventional digital convergence device.

[Explanation of symbols]

3 Pattern generation section 4 Frame memory 6 D/A conversion section 7 LPF 8 Control panel 12 Address generation section 14, 15 Sample hold circuit (S/H) 16
Arithmetic control unit 19, 29 Time series processing data control unit 25, 55
Vertical interpolation part

Claims (3)

[Claims] 1. Display means for generating and displaying a plurality of convergence adjustment points on the screen of a color television receiver, and digitally processing and storing convergence correction amounts for each of the adjustment points and the entire screen in a time-sharing manner. a storage means, a reading means for reading out the correction data from the storage means in synchronization with a synchronization signal input to the receiver, and a first calculation means for interpolating the read correction data of each adjustment point. . A digital convergence device comprising: second calculation means for interpolating the read correction data for the entire screen; and addition means for adding each correction data from the calculation means. [Claim 2] The calculation means performs linear approximation interpolation on the correction data of each adjustment point, and performs interpolation calculation on the correction data of the entire screen from a straight line to a curved line approximation in accordance with the operation of the correction system. A digital convergence device according to claim 1, characterized in that: 3. Display means for alternately generating and displaying a plurality of main and sub convergence adjustment points horizontally and vertically on a screen of a color television receiver, and a convergence correction amount for the main and sub adjustment points. a storage means for digitally time-divisionally processing and storing the correction data; a readout means for reading out the correction data from the storage means in synchronization with a synchronization signal input to the receiver; A digital convergence device comprising a calculation means for interpolating correction data of adjustment points, and an addition means for adding each correction data from the calculation means.