JPH0671326B2 - Electron beam landing correction device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam landing correction device in an image display device.

2. Description of the Related Art As a conventional electron beam landing correction device in an image display device, there is one disclosed in JP-A-61-121682. FIG. 4 is a block diagram showing the main part of the apparatus. Reference numeral 1 denotes an image screen in which phosphors of three primary colors are vertically arranged in stripes and divided horizontally into a plurality of bands. , An electron gun provided for each band of the image screen 1 for emitting an electron beam, and 3 is an index detection circuit for detecting the position of the electron beam, and corresponds to an index detection circuit used in a beam index type CRT. To do. Reference numeral 4 is a memory for storing landing correction data for each pixel of the image screen 1, and since a plurality of bands of the image screen 1 emit light at the same time, a number equal to or greater than the number of divisions of the screen is provided. The capacity is the same as the number of pixels on the screen.
Reference numeral 5 denotes a landing control circuit which is the same as the number of divisions of the image screen 1 which gives timing for driving the electron gun 2 by timing the landing correction data from the memory 4 and the position detection signal from the index detection circuit 3.
Is a position detection circuit for measuring the position of the electron beam at an arbitrary position on the image screen 1.

FIG. 5 is an operation signal diagram showing operation signals of main parts in the conventional example. (A) is a position detection signal from the index detection circuit, (b), (c) and (d) are timing signals for driving the electron gun in the n-1, n, and n + 1 lines, respectively, and (e) is This is the correction data for each line.

The operation of the conventional electron beam landing correction device configured as described above will be described below.

Based on the position of the electron beam at a predetermined position of the image screen 1 (for example, the edge portion of the image screen 1 which is not used for displaying an image), the image of the other part of the image screen 1 is obtained. By detecting the position of the electron beam for displaying, the index can always be detected at a constant level without changing the level of the detected position detection signal depending on the level of the image signal. With / N, an index detection circuit with good phase characteristics can be easily realized. In order to detect the position of the electron beam in the other part of the image screen 1 by using the position detection signal of the electron beam at the predetermined position of the image screen 1, according to each pixel of the image screen 1, FIG. The correction data as shown in (e) is required. This is because the system that scans the electron beam from the electron gun has different characteristics at different locations on the image screen, and close locations, but with greatly different characteristics, so the differences in characteristics are corrected. Is data for. Because of having this correction data, the landing correction data corresponding to each part of the image screen 1 is actually measured by the number of pixels of the image screen 1 and stored in the memory 4. When displaying an image, the landing control circuit 5 detects the position of the electron beam on the image screen 1 based on the signal from the index detection circuit 3 and the correction data stored in the memory 4, and the electron gun 2 emits an electron. The timing for emitting the beam is adjusted, and the electron gun 2 is driven by the timing signals as shown in FIGS. 5 (a), 5 (b), and 5 (c) to perform correct color reproduction.

Problems to be Solved by the Invention However, in the above-described configuration, since the correction data must be measured according to each pixel of the image screen, the measurement requires a long time, and the error of each correction data is large. Since there is no relation between adjacent lines,
There is a problem in that an error in color reproduction due to an error in the correction data occurs randomly between adjacent lines, which causes a sense of discomfort due to discontinuity in the image between the lines.

In view of the above point, the present invention has an object to provide an electron beam landing correction apparatus in which discomfort due to image discontinuity between adjacent lines is unlikely to occur.

Means for Solving the Problems The present invention provides a position detection circuit for detecting the position of an electron beam at a predetermined position on an image screen, and correction data for other positions on the screen from landing correction data at the predetermined position on the screen. The electron beam landing correction apparatus includes an arithmetic circuit for calculating, a memory for storing correction data, and a landing control circuit.

Operation According to the present invention, the landing correction data having a correlation is created between the adjacent lines by calculating the other landing correction data by the predetermined calculation by the landing correction data at the predetermined position with the above-mentioned configuration, By controlling the landing of the electron beam using the landing correction data, it is possible to reduce the discomfort due to the discontinuity of the image caused by the landing error between the adjacent lines.

First Embodiment FIG. 1 is a block diagram of an electron beam landing correction device according to a first embodiment of the present invention. The same parts as those in the conventional example are designated by the same reference numerals, and detailed description will be given. Omit it. Reference numeral 6 denotes an arithmetic circuit that generates landing correction data at another position from several pieces of landing correction data.

The operation of the electron beam landing correction apparatus of this embodiment constructed as above will be described below.

The landing correction data at each position of the image screen 1 is actually measured by the position detection circuit 7 in an arbitrary number of lines on the image screen 1 at the time of shipping or readjustment, and is stored in the memory 4. Next, based on the measured data, the arithmetic circuit 6 performs a predetermined arithmetic operation,
For example, linear interpolation calculation is performed to generate correction data for a portion that is not actually measured, and the correction data is stored in the memory 4. These operations will be further described with reference to FIG. The position detection circuit 7 measures the correction data of an arbitrary number of lines on the image screen 1, that is, the portions of the (n−2) th and (n + 2) th lines. These two correction data and the correction data of other lines have a correlation as shown in FIG. Therefore, the calculation circuit 6 applies a predetermined calculation such as linear interpolation to the actually measured correction data based on this correlation, and other parts, n-1, n, n +.
The correction data for one line can be calculated.

When displaying an image, the index detection circuit 3 detects the position of the electron beam at a predetermined position on the screen and outputs a position detection signal. This position detection signal and the memory 4
The landing control circuit 5 generates a timing signal for driving the electron gun 2 in accordance with the correction signal stored in the display unit 1, and causes the image screen 1 to display an image with correct color reproduction. At this time, if an ideal correction signal cannot be obtained due to an unavoidable error when actually measuring the landing correction data, the image on the image screen 1 will not be reproduced correctly in color. When such a problem occurs, when the correction data is actually measured and stored for each line as in the conventional case, since the error does not have any correlation between the adjacent lines, the image of each line is not correlated. Discontinuity occurs, and a sense of incongruity is observed. However, according to this embodiment, since the correction data of the other part is obtained based on the actually measured correction data having a certain error component, it is possible to give a strong correlation to the error of the correction data of each line, that is, The color reproduction error caused by the error in the correction data also has a strong correlation, and the discomfort due to the discontinuity of the image is not observed.

As described above, according to this embodiment, by providing the arithmetic circuit for generating the landing correction data by calculation, the time and effort for actually measuring the correction data can be greatly reduced, and the image error caused by the error of each correction data can be reduced. Discomfort due to continuity can be made less observable.

FIG. 2 is a block diagram of an electron beam landing correction apparatus according to the second embodiment of the present invention. The difference from the configuration of FIG. 1 is that the in-line arithmetic circuit 8 is provided so as to generate the correction data in each line based on other actually measured data in the line.

The operation of the electron beam landing correction apparatus of the second embodiment having the above configuration will be described below.

FIG. 3 is a block diagram illustrating the operation of the position detection circuit 7 of the second embodiment. The electron beam emitted from the electron gun 2 scans the image screen 1 to display an image, and the landing correction data of each pixel in each line of the screen has a strong correlation.
Therefore, in order to obtain the landing correction data of each pixel, it is sufficient to actually measure only the correction data of several pixels and then calculate it by linear interpolation calculation or the like. This calculation is performed by the in-line calculation circuit 8. For example, as shown in FIG. 3, only the landing correction data of the first and last pixels of each band are measured, and the data of the remaining pixels are linearly complemented. It is calculated by a predetermined calculation of.

As described above, according to this embodiment, it is possible to greatly reduce the points to be actually measured when creating the landing correction data, and it is possible to greatly reduce the time and effort required at the time of factory shipment and readjustment. Also, by making the landing correction data for each pixel have a correlation within each line, it is possible to reduce unevenness in color reproducibility within the line.

In addition, in the second embodiment, the position where the correction data is actually measured is the first and last pixels of each block, but it is obvious that the position may be changed to another position or the number of measured positions may be increased. Further, in the above two embodiments, the portion for detecting the position of the electron beam is the left end of the image screen, but it is clear that it may be above or below the screen, and the landing correction data stored in the memory is all pixels. Need not be stored, and the correction data may be obtained by performing calculation every time it is needed.

EFFECTS OF THE INVENTION As described above, according to the present invention, landing correction data is generated for a pixel display device that detects the position of an electron beam only at a specific location on the screen and controls the landing of the electron beam on the entire screen. Not only can the time and effort required for measurement be significantly reduced, but image unevenness due to poor color reproducibility due to correction data errors can be made inconspicuous, so measurement accuracy when generating correction data Moreover, since the calculation accuracy can be deteriorated, its practical effect is very large.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment of the present invention, and FIG. 3 is a block showing an operation of a position detection circuit in the second embodiment. Figure,
FIG. 4 is a block diagram of a conventional electron beam landing correction device, and FIG. 5 is an operation signal diagram showing operation signals of main parts of the correction device. 1 ... Image screen, 2 ... Electron gun, 3 ... Index detection circuit, 4 ... Memory, 5 ... Landing control circuit, 6 ... Calculation circuit, 7 ... Position detection circuit, 8 ... In-line calculation circuit.

Claims (2)

[Claims] 1. An image screen in which phosphors are arranged in stripes in a vertical direction and divided into a plurality of bands in a horizontal direction, and a plurality of electron guns for scanning each band of the image screen. , An index detection circuit for detecting the position of the electron beam on the screen in a specific part of the image screen, a memory provided for each band of the image screen, a position detection signal from the index detection circuit and a memory A landing control circuit that gives a timing to drive the electron gun based on the correction data, a position detection circuit that detects the position of the electron beam on the image screen at an arbitrary position on the image screen, and the position detection on several lines of the image screen. The correction data of each pixel measured by the circuit and index detection circuit. Electron beam landing correction device having an arithmetic circuit for calculating by interpolation the landing correction data of the other lines by using the data. 2. The landing correction data is taken in by only the data of a plurality of pixels of the pixels in a plurality of lines of each band, and the correction data of other pixels in the same line is interpolated using the taken data. The electron beam landing correction apparatus according to claim 1, further comprising an in-line arithmetic circuit that calculates by