JP2811996B2 - Automatic vertical landing adjustment device for image display devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television set which displays a plurality of scanning lines by vertically deflecting each electron beam when a screen on a screen is divided into a plurality of sections in a vertical direction. The present invention relates to a device for automatically adjusting a vertical landing position of a device for displaying an image.

[0002]

2. Description of the Related Art In recent years, various attempts have been made to make a color television picture tube into a flat tube structure.

Conventionally, a flat type color picture tube of this type has a configuration as shown in, for example, Japanese Patent Application Laid-Open No. 1-296284. Hereinafter, the configuration will be described with reference to the drawings.

As shown in FIG. 5, a rear electrode 1, a line cathode 2 for emitting an electron beam, an electron beam extraction electrode 3, an electron beam control electrode 4, and a convergence are arranged in this order from the rear toward an image display screen 8 on the anode side. An 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 vessel. The linear cathode 2 for emitting an electron beam is stretched in the horizontal direction, and emits an electron beam distributed linearly in the horizontal direction. In addition, a plurality of lines (only seven lines 2 to 2 are shown in FIG. 5) are provided at intervals in the vertical direction. The line cathode 2 is controlled so as to emit an electron beam from the upper line cathode 2a to the lower two cathodes in order for a predetermined time. The back electrode 1 not only suppresses the generation of electron beams emitted from the line cathodes other than the corresponding line cathode, but also pushes out the electron beams only in the anode direction. The beam extraction electrode 3 is a conductive plate 11 having a large number of through holes 10 provided at predetermined intervals in the horizontal direction facing each of the linear cathodes 2a and 2b.
The electron beam emitted from the linear cathode 2 is taken out through the through hole 10. The control electrode 4 is a linear cathode 2a ~
It is composed of a vertically long conductive plate 15 having a through hole 14 at a position facing each of the two grids, and a plurality of conductive plates 15 are arranged side by side in a horizontal direction with a predetermined interval. Here, the control electrode 4
Controls the passing amount of each of the electron beams, which are obtained by dividing the electron beam in the horizontal direction by the extraction electrode 3, corresponding to the picture element of the video signal and in synchronization with the horizontal deflection timing. The focusing electrode 5 is a conductive plate 17 having a through hole 16 at a position facing each through hole 14 provided in the control electrode 4, and focuses an electron beam. Horizontal deflection electrode 6
Is composed of a plurality of conductive plates 18 and 18 ′ vertically arranged along both horizontal sides of the through hole 16, and a horizontal deflection voltage is applied to each of the conductive plates 18 and 18 ′. ing. The electron beam for each picture element is deflected in the horizontal direction, and emits light by sequentially irradiating the R, G, and B phosphors 20 on the image display screen 8. Here, each electron beam is deflected by two trios. The vertical deflection electrode 7 includes a plurality of conductive plates 19, 1 arranged in the horizontal direction at intermediate positions in the vertical direction of the through holes 16.
The vertical deflection voltage is applied to deflect the electron beam in the vertical direction. Here, a pair of electrodes 1
The electron beams emitted from one linear cathode are deflected by 8 lines in the vertical direction by 9 and 19 '. The image display screen 8 has the phosphor 20 applied in a stripe shape on the back surface of the glass plate 21, and a metal back and carbon are also applied.

The operation of the image display device configured as described above will be described below. The electron beam emitted from the linear cathode 2 is controlled by a video signal applied to the control electrode 4. Here, the video signal applied to the control electrode 4 is pulse-width modulated for each of the three color signals of R, G, and B corresponding to each picture element of the video signal. Since it is described in Japanese Laid-Open Patent Application No. 57-133780, the description is omitted here. The electron beam controlled for each of the picture elements includes a horizontal deflection electrode 6 and a vertical deflection electrode 7.
Is deflected by the deflection voltage applied to the image display screen 8 to irradiate the phosphor 20 of the image display screen 8 to display an image. The back surface of the phosphor 20 is metal-backed, and a high voltage is applied thereto.

In order to automatically adjust the vertical deflection voltage of each line cathode of the image display device described above, a screen for image display is captured as data using a CCD camera and a lens, and the data is processed and adjusted. At that time, it is necessary to adjust the focal length of the lens. Conventionally, this adjustment is performed visually.

[0007]

The vertical landing automatic adjustment device for an image display device described above captures a screen of the image display device with a camera, analyzes a video signal of the screen,
Although the vertical landing position is adjusted based on the analysis result, if the focal length of the camera lens that captures the screen of the image display device is not good,
The vertical landing position cannot be adjusted due to moire.

For the above reasons, it is necessary to adjust the focal length of the lens of the camera to a distance at which moire is minimized.
Conventionally, the distance at which moiré is minimized is visually determined.
The focal length was manually adjusted.

The present invention solves the above-mentioned problems. The present invention enables a focal length to be arbitrarily adjusted by a personal computer using a motor for driving a lens of a camera and an interface for motor control. It is an object of the present invention to provide a method of detecting a component and automatically adjusting a focal length by adjusting the focal length to a distance that minimizes a moiré component.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a television camera capable of measuring the brightness of the entire screen of an image display device, and A / D conversion of a video signal from the television camera. An A / D converter, a controller for controlling landing position data of the image display device, a personal computer for processing video signal data and controlling the controller, and changing a focal length of a lens of a television camera to an arbitrary distance. And a motor control interface.

[0011]

According to this structure, by taking a predetermined procedure, the video signal of the screen is subjected to frequency analysis to detect a moiré component, and the focal length of the camera is automatically adjusted by adjusting the distance to the minimum value of the moiré component. can do.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an automatic vertical landing adjustment device of the image display device 50 having the above-described configuration. The image display device 50 is fixed in front of a television camera 56 having a lens 53 capable of capturing an image of the entire screen. I have. Driving motor 54 attached to lens 53
Can be controlled by the personal computer 52 by the motor control interface 55, and the focal length of the lens 53 can be freely changed. The data is input to a personal computer 52 that processes image data through an A / D converter 57 that converts a video signal of a television camera 56 into a digital signal. In addition, the personal computer 52 sends an electrode voltage control signal to the controller 51 based on a designated program in order to generate a vertical deflection voltage in a range where vertical landing should be adjusted.

Next, using a vertical landing automatic adjustment device having the structure shown in FIG. 1, the video signal of the screen is subjected to frequency analysis to detect a moiré component, and the focal length is automatically adjusted by adjusting the distance to minimize the moiré component. A method for performing the adjustment will be described with reference to FIGS. 2, 3, and 4. FIG.

First, the entire screen of the image display device 50 is captured by a television camera 56 having a lens 53 with a drive motor 54 attached thereto. The image signal is converted to an A / D converter 5
7, the image data is added in the horizontal direction and the vertical direction by the personal computer 52, and the average value of the luminance distribution in the horizontal and vertical directions is obtained. 2A illustrates an example of a horizontal or vertical luminance distribution when moiré occurs, and FIG. 2B illustrates an example of a horizontal or vertical luminance distribution when moiré does not occur.

Next, the personal computer 52 analyzes the frequency of the luminance distribution in the horizontal or vertical direction. FIG.
Is an example of a frequency analysis result. Since the frequency of moiré is determined by the distance between the image display device 50 and the television camera 56, if the power of the frequency spectrum in a certain frequency region is integrated and the value is defined as the intensity of moiré, the moiré can be quantitatively expressed. Can be.

The relationship between the moire intensity and the focal length can be clarified by repeating the above operation while controlling the lens 53 with the drive motor 54 by the personal computer 52 and changing the focal length. FIG.
9 shows an example of the relationship between the focal length and the moiré intensity. The moiré intensity becomes the maximum at point b, which is the just focus point, and points a and c before and after the point are slightly out of focus, but moire hardly occurs. That is, the moire component can be minimized by adjusting the focal length to the point a or the point c.

[0017]

As described above, according to the present invention, the video signal on the screen of the image display device is subjected to frequency analysis to detect a moiré component, and the focal length of the lens is adjusted by adjusting the distance to minimize the moiré component. Can be adjusted automatically.

[Brief description of the drawings]

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

FIG. 2 is a characteristic diagram for explaining the operation of FIG. 1;

FIG. 3 is a graph obtained by frequency analysis of a horizontal or vertical luminance distribution.

FIG. 4 is a diagram illustrating an example of a relationship between a focal length and moiré intensity.

FIG. 5 is a schematic perspective view showing a basic configuration of an image display device targeted by the present invention.

[Explanation of symbols]

 Reference Signs List 50 image display device 51 controller 52 personal computer 53 lens 54 motor 55 motor control interface 56 television camera 57 A / D converter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 3/227 H04N 3/227

Claims (1)

(57) [Claims] 1. A screen of an image display device is captured by a camera,
Analyzing the video signal of the screen, in the vertical landing automatic adjustment device of the image display device that adjusts the vertical landing position based on the analysis result, the focal length of the camera, the lens drive motor of the camera and A means for arbitrarily adjusting the focal length by a personal computer using a motor control interface; and a means for detecting a moiré component by frequency-analyzing a video signal of the screen. The output of the detecting means provides the focal length. An automatic vertical landing adjustment device for an image display device, wherein an adjustment means is controlled to automatically adjust to a distance minimizing the moiré component.