JPH0225594B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a dynamic convergence device that corrects color shift in a color cathode ray tube, and particularly relates to a digital dynamic convergence device that digitally stores color shift correction data. .

[Prior art]

Color cathode ray tube display devices such as television receivers have three electron guns for red, edge, and blue (hereinafter abbreviated as R, G, and B), and their electron beams are horizontally
A raster scan circuit that scans vertically, R, G,
It corresponds to the B electron beam and consists of the basic elements of a shadow mask and a fluorescent display screen for converting it into light. It is preferable that each electron beam on the fluorescent display screen gathers at one point in the entire range of raster scan, and when each beam has the same intensity, it becomes one white point, but in reality, due to mechanical dimensions Due to errors, distortions in the deflection magnetic field, etc., the light emitting points do not match, resulting in a color shift of several millimeters. In order to correct such color shift, conventionally, four magnets as shown in FIGS.
Static convergence correction is used to correct color shift by relatively deflecting the G and B electron beams.

With this permanent magnet, it is still difficult to accurately correct color misregistration over the entire surface of the phosphor screen.If a color misregistration of 1 mm or less is required, a magnetic field equivalent to that shown in Fig. 1 is generated using an electromagnetic magnet using a coil.
Dynamic convergence correction is performed by changing the current flowing through the coil in response to raster scan.

Conventionally, as a means of generating a correction current value for this dynamic convergence, an analog system using a combination of variable resistors, etc. has been exclusively used, but in recent years, with the advancement of digital technology,
Digital dynamic convergence devices have been proposed that store corrected current values digitally.

Figure 2 shows a principle block diagram of digital dynamic convergence (hereinafter abbreviated as DDC). That is, in the DDC device 10, the color shift correction data is stored in the correction data memory 2, and the data is converted into an analog value by the D/A converter 3, and the color shift correction coil 1 is driven.

As shown in FIG. 3a, the correction data memory 2 is assigned addresses corresponding to zones obtained by dividing the raster scan range into several horizontal and vertical sections, and the zone address generator 4
Generates a zone address corresponding to raster scan based on the synchronization signal from the deflection circuit 20,
The correction data input section, which is used to read correction data corresponding to the corresponding zone from the correction data memory 2, is used to input specific data to the correction data memory 2.

For example, when there is color shift in the center vertical direction as shown in FIG.
By storing the data shown in FIG. b, color shift can be corrected in the entire raster scan range.

It is clear that precise color shift correction is possible by making the zone division more fine-grained and by increasing the number of bits for storing correction data.

By the way, from the standpoint of using this DDC, it is important that the operation of inputting correction data is simplified and, furthermore, unnecessary. For end users, no adjustment is desired, but traditional DDC
However, there was the following problem, which made it impossible to achieve this goal. In other words, in general display applications other than televisions, the reality is that the scan frequency or scan size differs for each user, but when the horizontal or vertical scan frequency changes or the scan size changes, ,
Even if correctly corrected data is stored, there is a problem in that correct color shift correction cannot be performed with the data as it is.

[Purpose of the invention]

The object of the present invention is to determine the scan frequency or
An object of the present invention is to provide a more practical DDC device that enables no adjustment when changing the scan size.

[Summary of the invention]

The inventors focused on the fact that the amount of color shift in color cathode ray tubes mainly depends on the physical position on the display tube surface, and that the amount that depends on the raster scan size or scan frequency is extremely small, and developed a method for raster scan. A new means for importing parameters for associating zones with physical positions on the display surface has been added, and when the desired adjustment data is stored, these parameters are also stored at the same time, making it possible to prevent changes in these parameters. A method has been added to automatically re-edit the correction data to maintain the physical positional relationship between the initial data and the display screen even when performing raster scans using new parameters. Eliminates the need to readjust correction data.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

The DDC 10 that drives the color shift correction coil 1 is
Correction data memory 2, D/A converter 3, zone address generator 4, and correction data input section 1
Consists of 1 etc. The correction data input section 11 includes a keyboard 13, a raster size detection section 15, a microcomputer 12, and the like.

The zone address generator 4 includes the deflection circuit 2
The correction data memory 2 is for receiving a signal synchronized with raster scan from 0 to generate a zone address, and the correction data memory 2 is for storing correction data corresponding to the zone address. however,
Of the data areas, the flag bit area is an auxiliary area used to assist the correction data input operation, and the D/A converter 3 stores the correction data memory 2.
This is for driving the color misregistration correction coil 1 by D/A converting the correction data read from the .

Address multiplexer 6 and data register 7 are changeover switches for connecting correction data memory 2 to a correction data input section and for storing and reading data.

During the correction data input operation, the zone cursor generator 5 outputs to the display screen in which zone the correction data is entered and how the color shift is caused by the input correction data. It generates a cursor signal to inform the operator and drives the video amplifier.

The keyboard 13 is an operation console for inputting correction data, and can at least select and command the following functions. In other words, designation of the zone address where correction data is to be input (hereinafter referred to as zone cursor movement to the left and right) Correction data input (correction direction vector) Start and end of correction data input operation The raster size detection unit 15 detects the raster scanning area. In order to correlate the physical positional relationship between the
A/A voltage proportional to the horizontal and vertical scan width
This is for D-converting the data and importing it into the correction data input section. The microcomputer is used to control the correction data input operation, and when the correction data input operation command given from the keyboard 13 is executed and the raster scan parameter (frequency or size) changes, the correction data is re-edited. A program for executing the above is incorporated.

The memory 14 is a nonvolatile memory for storing raster scan parameters, correction data of the correction data memory 2, and the like.

FIG. 5 shows a detailed embodiment of the zone address generator 4. In FIG.

In this example, the number of horizontal zone divisions is 8,
The number of vertical rasters (number of vertical zones) is assumed to be up to 512 (therefore, the correction data memory 2 is
Has a 4K address. ).

First, the horizontal zone address generation section is PLL4.
1 and a 1/8 counter 42, and a deflection circuit 20.
By dividing the interval of horizontal synchronization H from 1/8 to 1/8,
Divide the raster scan area into 1/8. (Strictly speaking, all eight divisions cannot be displayed due to the retrace period, but in order to make the explanation easier to understand, the following explanation will ignore the retrace period.)

Next, the vertical zone address generating section is assumed here to simply update the zone for each horizontal scan, and consists of a 1/512 counter, which counts the horizontal synchronizing signal H from the deflection circuit 20. , when the vertical synchronizing signal V arrives, it is reset to 0. Therefore, in this zone address generator, the number of vertical zone divisions changes depending on the horizontal/vertical scan frequency.

Next, the color shift correction operation of the DDC device made up of these hardware will be explained.

First, the operation when the operating frequency or the raster scan size changes will be explained using vertical direction correction as an example.

In FIG. 6, when the correction data is input, it is assumed that color shift 4 has been corrected with the number of rasters being 512, as shown in FIG. 6a.

On the other hand, if the number of rasters remains unchanged and the scan width is reduced to 1/2 as shown in Figure 6b, the scan area of the raster will be reduced toward the center of the display screen, and the correction data will be changed to the original value. If left as is, overcorrection will occur, and the difference will appear as color shift.

Therefore, in order to eliminate the color shift, as shown in Figure 6b', the original data at address 128 is changed to data at address 0 (abbreviated as 0←256), 256←256, 512←
384, the data in the correction data memory 2 may be edited again. The address for this edit is
If the raster size reduction ratio is known based on address 256 (center address), it is possible to eliminate the need to re-enter new correction data.

Therefore, when the microcomputer 12 receives a command from the keyboard 13 to complete the correction data input operation, the output data of the raster size detection section 15 is
The data stored in the memory 14 is further patrolled to see if there is a change in the output data of the raster size detection unit 15, and when a change is detected, the correction data in the correction data memory 2 is changed using the algorithm described above. works.

Next, if the number of rasters is set to 256 (assuming that the raster scan size is kept constant) as shown in Figure 6 a to c, then if the original correction data remains unchanged, it will be insufficient correction, and the difference will be However, it also appears as a color shift.

Therefore, to eliminate color shift, set the correction data to 0←
If you re-edit like 0, 128←256, 256←512,
No new correction data input is required.

In this editing, the required information is the number of rasters, and this information is read in the following procedure. First, all flag bits in the correction data memory 2 are reset to "0". Next, "1" is written in the flag bits for all addresses designated by the zone address generator. This operation involves switching the input of the address multiplexer 6, switching to the zone address 4 side, setting "1" in the data register 7, issuing a reload command to the correction data memory 2, and waiting for a certain period of time longer than one frame scanning time. is executed. After that, by checking the address whose flag bit is set to "1", the zone address generator can detect to which range the transition has occurred. Since the correction data must not be destroyed by this operation, writing of the flag bits in the correction data memory 2 is configured so that it can be designated independently of the correction data section.

When a command to complete the correction input operation is received from the keyboard, this raster number data is stored in the memory 14, and the raster number data is patrolled to see if there has been a change in the number of rasters. When a change is detected, the above-mentioned algorithm is used. A series of operations for editing the correction data is also executed by the program of the microcomputer 12. In this way, once, the 6th
Once the color misregistration correction shown in FIG.

Next, a method of inputting color shift correction data will be explained.

Upon receiving a command to start inputting color shift correction data from the keyboard 13, the microcomputer 12
performs control for the following correction data input operations.

The flag bits in the correction data memory 12 are used as zone cursor display information for correction. That is, the zone address generator 5
is configured to output a pulse signal that displays the spot point at the center of the zone when this flag bit is "1", and this zone cursor pulse is sent to the cathode ray tube 4 through the video amplifier 30.
0 R, G, B electron gun 3 is excited. Thus,
A spot is displayed on the display screen. The correction data in the correction data memory 2 is updated for addresses whose flag bit is "1".
This flag bit is written directly by the microcomputer 12. The operator looks at the zone cursor spots on the display screen and, if the three color spot positions of R, G, and B are shifted (color shift), gives a data correction command (correction direction) from the keyboard 13. The microcomputer 12 updates the correction data at the address in the correction data memory 2 in accordance with the command. At this time, the timing at which the microcomputer 12 accesses the correction data memory 2 is controlled to be performed during the blanking period, and the address of the correction data memory 2 is not updated by the zone address generator 4 other than the blanking period. The display screen does not change when data is updated, and the operator can continue issuing data correction commands until the three color dots of R, G, and B match. When the three color dots match and the correction for the zone is completed, the operator presses the keyboard 1
From step 3, the zone cursor movement is commanded and the correction of the next zone begins. Correction input does not necessarily have to be performed for all zones; if you apply corrections at regular intervals and write interpolated data for the rest, the correction operation can be shortened, so it is possible to reduce the number of zone cursors. Move the microcomputer 12
It is preferable to program it in advance. When performing such a jump-up movement, when a correction end command is received from the keyboard 13, it is necessary to insert interpolation data.

In the figure, 7 is a data register, 21 is a deflection coil, and 43 is a counter that divides the input signal into 1/512.

〔Effect of the invention〕

According to the present invention, when the raster scan frequency or raster size is changed, color shift correction data can be automatically reset.
There is no need for readjustment operations.

[Brief explanation of drawings]

1A to 1D are schematic diagrams of the principle of the object of the present invention, FIG. 2 is a conventional block diagram, FIG. 3 a and b are explanatory diagrams of conventional operation, and FIG. 4 is an overall block diagram of the present invention.
FIG. 5 is a partial block diagram of the present invention, FIG. 6a,
b, c, b', c' are diagrams explaining the operation of the present invention. 1... Correction coil, 2... Correction data memory,
3...D/A converter, 4...Zone address generator, 12...Microcomputer, 13
...Keyboard, 15...Raster size detection section.

Claims (1)

[Scope of Claims] 1. A color shift correction coil for correcting color shift of a cathode ray tube, a memory for digitally storing this correction amount, and synchronized with raster scan scanning,
A zone address generator that associates the raster scan position with a memory address from the memory, and converting data read from the memory address specified by the zone address generator into an analog quantity to correct the color shift. In the dynamic convergence device, means for detecting the raster scan frequency and the raster size, means for storing the raster scan frequency and the raster size together with correction data, and a means for detecting the raster scan frequency and the raster size, and a means for storing the raster scan frequency and the raster size together with correction data; means for updating the correction data in the memory by predictively calculating the correction data after the change from the color shift correction data, the raster scan frequency or raster size before the change, and the raster scan frequency or raster size after the change. A digital dynamic convergence device with special features.