JPH04253490A - Color television receiver - Google Patents

Abstract

PURPOSE:To realize the color television receiver ensuring convergence adjustment without deterioration in picture quality such as deterioration in the focus characteristic in the color television receiver employing a cathode ray tube. CONSTITUTION:An inputted video signal 11 is converted into a digital video signal by an A/D converter 12 and stored in a picture memory 13. An address control section 15 applies address conversion to a digital video signal stored in the picture memory 13 and reads the result according to an address designated by a conversion address reference table 16 storing correction data based on a mis-convergence data and the data is displayed on the color television receiver via a digital address converter 14.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color television receiver having a convergence function for correcting misconvergence in the color television receiver.

0002

[Prior Art] In recent years, compared to conventional television receivers,
There is an increasing demand for large-screen images that provide even more power and a sense of presence, as well as for more detailed images. Therefore, there is a demand for higher image quality with less image quality deterioration such as color shift. In addition, semiconductor technology has made remarkable progress, and high-performance television receivers based on digital signal processing using image memory and the like have been put into practical use.

By the way, in general, cathode ray tubes (hereinafter referred to as CRTs)
In color television receivers of this type, electromagnetic deflection is the mainstream method for controlling the electron beam that causes the phosphors to emit light. Phosphor red
It is necessary to perform a so-called convergence operation in which green and blue (hereinafter referred to as R, G, and B) colors are superimposed. That is,
In a CRT direct-view type television receiver, convergence is required to concentrate the three electron beams that cause the R, G, and B phosphors to emit light on a shadow mask. This requires convergence, in which monochrome CRT images are magnified through a lens and superimposed on a screen.

A conventional convergence method will be explained below with reference to the drawings. Conventionally, this convergence is the CR
Basically, we use a method of controlling the magnetic field using the T structure, deflection yoke, convergence magnet, convergence yoke, etc., and strictly concentrate three electron beams on the shadow mask.
In the projection type, three CRTs are driven synchronously, and the structure of the projector, deflection yoke, convergence magnet, convergence yoke, etc. are used to control the magnetic field, and the three electron beams are projected onto a screen. The method used is to overlap three images on the screen, as if concentrating on the top.

FIG. 3(a) shows the display state based on the video signal that should originally be displayed on the television screen of the television receiver, and FIG. This figure shows an example of a monochromatic image displayed on a television screen with a distorted raster (electron beam scanning area). In FIG. 3, 31 is a television screen;
2 is an undistorted raster, 33 is an undistorted image (
(in this case a rectangle), 34 is a distorted raster, 35
is a distorted image.

[0006] In this way, since the raster is distorted separately for each of R, G, and B, the R, G, and B images are also distorted, and when they are combined to create a color image, the colors will be shifted. However, the conventional convergence method corrects raster distortion by adding correction to the deflection magnetic field and controlling the electron beam with the magnetic field, and superimposes R, G, and B colors. .

[0007]

[Problems to be Solved by the Invention] However, since the above method uses a means of controlling the magnetic field for the electron beam, the path of the electron beam to reach the fluorescent screen changes, causing the convergence of the electron beam to change. influence,
There is a problem in that misconvergence occurs due to deterioration of focus characteristics or changes in characteristics with respect to temperature drift of components of the analog circuit that generates the correction magnetic field.

The present invention takes the above-mentioned problems into consideration and provides a color television receiver that provides stable convergence without deterioration of image quality.

[0009]

[Means for Solving the Problems] In order to achieve the above object of the present invention, in a color television receiver using a cathode ray tube, an analog-to-digital converter converts an input video signal from analog to digital, and stores the output. The apparatus includes a memory for converting the address of the video signal stored in the memory, an address control section for converting the address of the video signal stored in the memory, and a display means for displaying the digital video signal whose address has been converted by the address control section.

0010

[Operation] The color television receiver of the present invention having the above configuration converts a video signal into a digital signal using an analog-to-digital converter, and stores the resulting digital video signal in a memory with addresses assigned corresponding to each of the television screens. be done. This signal is stored for each R, G, and B color signal, and is a signal to which an address to be displayed on the television screen is assigned. This digital video signal is sequentially read out by the address control section, and the misconvergence caused by the combination of the cathode ray tube and the electromagnetic components that control its electron beam has been measured in advance, and correction data based on this is used to correct R, G, Address translation is performed for each B. In other words, the amount of misconvergence that occurs when the video signal is displayed as it is on a television screen is converted to digital, and the address value of the digital video signal is corrected for each R, G, and B color signal.
Works to correct misconvergence on the television screen.

[0011] This misconvergence-corrected digital video signal is converted into an analog video signal by a projection means via a digital-to-analog converter, and is displayed on a television screen.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the main parts of a color television receiver according to an embodiment of the present invention. The same applies to video signals. As shown in FIG. 1, its components include an input video signal 11 and an analog-to-digital converter (hereinafter referred to as A/D).
13 is an image memory, 14 is a digital-to-analog converter (hereinafter referred to as a D/A converter), 15 is an address control section, and 16 is a conversion address reference table.

Regarding the television receiver configured as described above, the related operations of its constituent elements will be explained using FIG. 2.

As shown in FIG. 2(a), when the raster 22 is not distorted, an undistorted image 23 is displayed on the television screen 21;
When the image is distorted as shown in FIG. 2, the distorted image 25 is displayed on the television screen 21. In the present invention, by processing a video signal using the configuration shown in FIG. 1 without correcting the distorted raster 24, the raster is distorted on the television screen 21 as shown in FIG. 2(c). An undistorted image 26 similar to the image 23 when the image is not displayed is displayed, and if this processing is performed for each of R, G, and B, convergence can be achieved.

[0015] This processing is a graphical conversion performed by computer graphics, and when used as a color television receiver, this conversion is performed by an electromagnetic system that controls the cathode ray tube and its electron beam for each receiver. Since the value is fixed depending on the combination of parts, it can be realized by using a translation address reference table as shown in FIG. The input video signal 11 is sent to the address control section 15.
The image data is digitized by the A/D converter 12 and written into the image memory 13 under the control of the A/D converter 12 . For output, data specified by the conversion address reference table 16 is read from the image memory 13, and an analog signal is obtained by the D/A converter 14. This analog signal is displayed by the display means.

By detecting this analog signal, the raster 24 remains distorted as shown in FIG. 2(c);
The target rectangular image is projected as a video 26 without distortion. By performing this operation similarly for each of the R, G, and B colors, it is possible to obtain a high-quality color image in which image distortion is corrected and misconvergence is also corrected. The address conversion data using the conversion address reference table is based on the data to be corrected for each color, which can be obtained in advance from the image projected by the combination of the cathode ray tube and the electromagnetic components that control its electron beam. data is stored.

[0017] The above embodiment takes into consideration the case where the original R, G, and B images are arbitrarily distorted.
If you are thinking of applying it only to parallel movement in the horizontal, vertical, or diagonal direction, you can use a simpler configuration than the one shown in Figure 1, which can also be achieved by address conversion. can do.

[0018]

Effects of the Invention As is clear from the above explanation, according to the present invention, an image memory for storing a video signal is used, and R.
By reading data suitable for the screen position scanned by each electron beam that makes the G and B phosphors emit light from the image memory and displaying it, an image without color shift can be obtained, and the magnetic field can be Since convergence can be achieved without using a control method, it is possible to avoid deterioration of focus characteristics or misconvergence caused by changes in the characteristics of circuits and components used to control the magnetic field. A high-quality color television receiver can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the main parts of a color television receiver according to an embodiment of the present invention.

[Fig. 2] (a) is a pattern diagram showing an example of a projected image for explaining the operation of the same embodiment; (b) is a pattern diagram of a television screen before convergence correction for explaining the operation of the same embodiment; The video pattern diagram (c) projected on the screen is a diagram of the video pattern projected on the television screen after convergence correction for explaining the operation of the same embodiment.

[Figure 3] (a) and (b) are image pattern diagrams projected on the television screen of a conventional television receiver.

[Explanation of symbols]

12 Analog-digital converter 13 Image memory 14 Digital analog converter 15 Address control section 16 Conversion address reference table

Claims (2)

[Claims] 1. An analog-to-digital converter for converting a video signal into a digital signal, a memory for storing a digital video signal obtained by the analog-to-digital converter, and an address for the digital video signal stored in the memory. 1. A color television receiver comprising: an address control unit for converting the address; and display means for displaying the digital video signal whose address has been converted by the address control unit. 2. The color television receiver according to claim 1, further comprising a translated address reference table in which address translation rules are stored, and wherein address translation by the address control unit is performed based on the translated address reference table. .