JPH05191846A - Automatic horizontal landing adjusting method for image display device - Google Patents

Abstract

PURPOSE:To automatically adjust the horizontal landing position of an image display device where a single phosphor is coated by calculating the total sum of brightness conversion quantity, inspecting the periodic bright and dark occurrence of brightness and judging an optimum horizontal deflection voltage amplitude. CONSTITUTION:The whole part of a screen in the image display device 50 is image- picked-up by a CCD television camera 54, the signal is converted into a digital signal by an A/D converter 53 so as to be inputted to a personal computer 52 and a brightness distribution corresponding to respective scanning lines is obtained. Next, the personal computer 52 calculates the total sum of change quantity in the brightness distribution. That is, the horizontal deflection voltage amplitude where the total sum of brightness change quantity becomes min. is the optimum amplitude. The operation is repeated by controlling a controller 51 as against the respective scanning lines by the personal computer 52 while gradually changing the horizontal, deflection voltage amplitude so that relation between the total sum of the brightness change quantity of the respective scanning lines and the amplitude is made to be clear and the amplitude of the horizontal deflection voltage in the respective scanning lines is adjusted so as to be optimum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention deflects each electron beam when a screen projected on an image display screen surface is divided into a plurality of sections in the vertical direction and deflects the electron beams in the horizontal and vertical directions. The present invention relates to a method for automatically adjusting a horizontal landing position of an image display device that displays scan lines and displays a television image as a whole.

[0002]

2. Description of the Related Art In recent years, various attempts have been proposed to make a color television picture tube a flat tube structure. Conventionally, a flat type color picture tube of this kind has a structure as shown in, for example, Japanese Patent Laid-Open No. 157590/1982. The configuration will be described below with reference to the drawings.

As shown in FIG. 4, the image display screen 8
From the rear toward the rear, a back electrode 1, a line cathode 2 that emits an electron beam, an electron beam extraction electrode 3, an electron beam control electrode 4, a focusing electrode 5, a horizontal deflection electrode 6, a vertical deflection electrode 7, and an image display screen 8. Are arranged, and the whole is housed in one vacuum container. The linear cathode 2 that emits an electron beam is stretched in the horizontal direction and emits an electron beam that is linearly distributed in the horizontal direction. Further, a plurality of lines (only 7 lines 2 to 2 are shown in FIG. 4) are provided at intervals in the vertical direction. The above-mentioned line cathode 2 is controlled so as to sequentially emit an electron beam from the upper line cathode 2a to the lower line cathode 2g for a fixed period of time.

The back electrode 1 not only prevents the generation of electron beams emitted from other line cathodes but also pushes out the electron beams only to the image display screen 8.

The beam extraction electrode 3 is composed of line cathodes 2a-2.
A plurality of through holes 10 arranged in the horizontal direction at regular intervals facing each other are taken out.

The control electrode 4 is composed of a vertically long conductive plate 15 having a through hole 14 at a position facing each of the line cathodes 2a to 2t, and a plurality of control electrodes 4 are arranged side by side in a horizontal direction at a predetermined interval. Has been done. Here, the control electrode 4 corresponds the passing amount of each electron beam horizontally divided by the electron beam extraction electrode 3 to the picture element of the video signal,
Moreover, the control is performed in synchronization with the horizontal deflection timing.

The focusing electrode 5 is a conducting plate 17 having a through hole 16 at a position facing each through hole 14 provided in the control electrode 4, and focuses the electron beam.

The horizontal deflection electrode 6 is composed of a plurality of conductive plates 18 and 18 'vertically arranged along both sides of the through hole 16 in the horizontal direction. The deflection voltage is applied. The electron beam along each picture element is deflected in the horizontal direction, and the R, G, and B phosphors 20 are sequentially irradiated on the surface of the image display screen 8 to emit light. 2 here for each electron beam
Deflection by the trio.

The vertical deflection electrode 7 is composed of a plurality of conductive plates 19 and 19 'arranged in parallel in the horizontal direction at intermediate positions in the vertical direction of the through-hole 16, and a vertical deflection voltage is applied to the vertical deflection electrode 7 to emit an electron beam. Vertically biased. here,
An electron beam emitted from one line cathode is vertically deflected by eight lines by a pair of electrodes 19 and 19 '.
That is, as shown in FIG. 5, one horizontal section has six beam spots, and one vertical section has a horizontal scanning line 8
It is composed of lines.

The image display screen 8 has a fluorescent material 20 applied in stripes on the back surface of a glass plate 21, and a metal back and carbon for black stripes are applied. A high voltage is applied to the metal-backed portion of the image display device 8 to form an acceleration electrode.

The operation of the image display device configured as described above will be described below. The flow rate of the electron beam emitted from the line cathode 2 is controlled by the through hole 14 according to the video signal applied to the control electrode 4. Control electrode 4 here
The video signal added to the video signal is pulse width modulated corresponding to each picture element of the video signal (Japanese Patent Laid-Open No. 1355/1982).
No. 90). The electron beam controlled for each picture element is deflected by the deflection voltage applied to the horizontal deflection electrode 6 and the vertical deflection electrode 7, and illuminates the phosphor 20 of the image display screen 8 to display an image. A high voltage is applied to the metal-backed acceleration electrode on the back surface of the phosphor 20.

In order to adjust the horizontal deflection landing position of each scanning line of the image display device described above, it is necessary to select a horizontal deflection voltage such that a beam spot exists in the center of each phosphor. Conventionally, since the image display clean 8 is coated with phosphors of three colors of R, G, and B on each picture element, the beam spot for adjusting the horizontal landing position is gradually changed by changing the horizontal deflection voltage. The phosphors are irradiated to emit light, the brightness is measured through a color filter of the same color as each phosphor, the relationship between the horizontal deflection voltage and the brightness is determined, and the horizontal deflection voltage is determined and adjusted based on the result.

[0013]

The horizontal landing automatic adjusting device of the image display apparatus as described above has a horizontal deflection voltage with which a beam spot hits the center of each phosphor in order to adjust the horizontal deflection landing position of each scanning line. Need to choose. As described above, since the conventional image display device is coated with phosphors of three colors, in order to perform horizontal landing adjustment, the horizontal deflection voltage is gradually changed, the beam spot for adjustment is moved, and the brightness is measured. Brightness is measured through a color filter of the same color as the desired phosphor, and the horizontal deflection voltage is determined by the relationship between the horizontal deflection voltage and brightness. It was impossible to adjust the image display device.

The present invention solves the above problems by providing a means for changing the horizontal deflection voltage of each scanning line and a means for detecting a change in the brightness of each scanning line by using a camera. The horizontal landing position of the image display device coated with a single phosphor is determined by calculating the total amount of the amount of light, checking whether periodic brightness contrast occurs, and determining the optimum horizontal deflection voltage amplitude. The purpose is to provide a method of automatic adjustment.

[0015]

In order to solve the above problems, the present invention provides a CCD camera capable of measuring the brightness of the screen of an image display device, an A / D converter for converting a video signal from analog to digital, A feature is that automatic adjustment of horizontal landing is performed using a controller that controls landing position data of the image display device and a personal computer that processes data of a video signal and controls the controller.

[0016]

With this configuration, the horizontal deflection voltage of each scanning line of the image display device coated with the phosphor of a single color is adjusted by the following procedure.

With respect to all the scanning lines of the image display device, the amplitude of the horizontal deflection voltage is changed at a constant interval by the image display device controller, and the luminance distribution of all the scanning lines at that time is imaged by the camera, and the A / D After conversion, calculate the brightness distribution corresponding to each scanning line, calculate the sum of the changes in the brightness distribution, and check whether periodic brightness contrast occurs to determine the optimum horizontal deflection voltage amplitude. Then, the horizontal landing position of each scanning line is adjusted.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the image display device 5 having the above-mentioned structure.
The image display device 50 is fixed in front of a CCD television camera 54 which is a horizontal landing automatic adjustment device of 0 and which can take an image of the entire screen. The video signal of the CCD camera 54 is converted into a digital signal by the A / D converter 53 and input to the personal computer 52 which processes the image data. Further, the personal computer 52 sends an electrode voltage control signal to the controller 51 based on an instructed program in order to generate a horizontal deflection voltage in a range where the horizontal landing position should be adjusted. Next, a method of adjusting the amplitude of the horizontal deflection voltage of each scanning line of the image display device coated with only the phosphor of a single color by using the horizontal landing automatic adjusting device having the configuration of FIG. 1 will be described with reference to FIGS. Will be explained.

First, the entire screen of the image display device 50 is imaged by the CCD television camera 54, the signal is converted into a digital signal by the A / D converter 53, and the digital signal is input to the personal computer 52 and the luminance distribution corresponding to each scanning line is obtained. Ask for. In FIG. 2, (a) shows the luminance distribution of the scanning line in which the peaks of the luminance distribution may occur because the beam spots overlap when the horizontal deflection voltage amplitude is large, and (b) shows the beam spot when the horizontal deflection voltage amplitude is optimum. The brightness distribution of the scanning line that may have a flat brightness distribution due to the uniform distribution of the lines. (C) The brightness of the scanning line where the valleys of the brightness distribution may occur because the beam spots are separated when the horizontal deflection voltage amplitude is small. An example of distribution is shown.

Next, the personal computer 52 calculates the total sum of the changes in the luminance distribution. FIG. 3 shows an example of the relationship between the sum of the amount of change in luminance and the amplitude. In other words, the horizontal deflection voltage amplitude that minimizes the total sum of brightness changes is the optimum amplitude. In FIG. 3, (b) is the optimum amplitude.

The above operation is repeated for each scanning line by controlling the controller 51 by the personal computer 52 and gradually changing the horizontal deflection voltage amplitude to thereby obtain the sum of the amount of change in the brightness of each scanning line and the amplitude. The relationship can be clarified, and the amplitude of the horizontal deflection voltage of each scanning line can be optimally matched.

[0023]

As described above, according to the present invention, it is possible to easily adjust the amplitude of the horizontal deflection voltage of the image display device coated with the phosphor of a single color.

[Brief description of drawings]

FIG. 1 is a block diagram of a horizontal landing automatic adjustment device for an image display device according to an embodiment of the present invention.

2A and 2B are diagrams showing luminance distributions of scanning lines.

FIG. 3 is a diagram showing a sum total of changes in amplitude and brightness.

FIG. 4 is a perspective view showing the structure of a basic image display device.

[Explanation of symbols]

 50 image display device 51 controller 52 personal computer 53 A / D converter 54 CCD camera

Claims (1)

[Claims] 1. An image display screen coated with a phosphor of a single color that emits light when irradiated with an electron beam, and an electron beam is generated for each vertical section obtained by vertically dividing the screen on the image display screen. A line cathode, a separating means for separating an electron beam generated by the line cathode in each horizontal direction and irradiating the image display screen surface with each horizontal section, and a plurality of steps of the electron beam in the vertical direction and the horizontal direction. A deflection electrode for deflecting the electron beam, an electron beam control back electrode for controlling the amount of the electron beam separated for each horizontal section on the image display screen surface, and an acceleration electrode for accelerating the electron beam. In the image display device, the sum of the variation amounts of the luminance distribution is obtained by using a unit that changes the horizontal deflection voltage of each scanning line and a unit that detects the luminance distribution of each scanning line. A method for automatically adjusting the horizontal landing of an image display device, in which the optimum amplitude of the horizontal deflection voltage is determined by examining the occurrence of periodic brightness contrast.