JPH02285390A - Burning prevention system for cathode-ray tube screen - Google Patents

Abstract

PURPOSE:To make the fluorescent film of a cathode-ray tube(CRT) hard to burn by not fixing the display position of a still picture displayed on the CRT. CONSTITUTION:A CPU 1 is connected to other various element equipments and input/output equipments by a bus line 2. A fixed program that the CPU system executes is recorded on a read-only memory 4 and information for processing, data in arithmetic processing, etc., are stored temporarily on a read/write memory 5. In a pattern display system using the CRT 3 controlled by this CPU 1, the display position of a still picture displayed on the CRT 3 is not fixed. Consequently, the same position on the fluorescent film of the CRT 3 is never irradiated continuously with an electron beam. Consequently, the life of the CRT can be prolonged.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an information display device using a cathode ray tube in a computer device, and in particular to a method for preventing burn-in of a cathode ray tube screen that increases the life of the cathode ray tube. Regarding.

[Prior Art] Conventionally, in various devices that utilize a computer (hereinafter referred to as CPU), a cathode tray tube (hereinafter referred to as CR) is used to display various leakage information held by the computer to the operator.
(denoted as T) is used.

To display graphics or characters on a CRT, the information to be displayed sent from a storage device etc. is divided and distributed among the pixels on the CRT according to predetermined conditions by the control circuit of the device, and horizontal synchronization signals and vertical Combined with synchronization signal and sent to CRT
It is transmitted to a display circuit and displayed on a CRT. Therefore, the same information is always displayed in the same location on the CRT.

[Problems to be Solved by the Invention] When displaying characters and figures using a CRT as described above, still images are often displayed. When displaying a still image, the same location on the CRT is continuously irradiated with an electron beam, so the fluorescent film of the CRT in the area that is continuously irradiated with the electron beam suffers so-called film burn.
Images on CRTs with film burns have color spots or defects, resulting in a decrease in quality, making it difficult to put them into practical use. The time it takes for film burn to occur varies depending on brightness adjustment conditions and frequency of use, but there are actual cases where it occurs after 4 to 5 years.

This can be said to be a lifespan of approximately 10,000 hours, assuming an operation of 8 hours a day and 300 days a year.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a control system that prevents the fluorescent film of a CRT from being burned.

[Means for Solving the Problems] In order to solve the above-mentioned problems and provide a display device that does not easily cause film burn on the fluorescent film of a CRT, the present invention provides a pattern display system using a CRT controlled by a CPU. The second invention is characterized in that the display position of the still image displayed on the CRT is not fixed, and the address reference position is shifted with respect to the display address of the still image before the display address on the CRT is cleared. It is characterized by

[Function] In the present invention, since the display position of a still image displayed on a CRT is not fixed, the same part of the fluorescent film of the CRT is not continuously exposed to the electron beam, and the surface of the fluorescent film is Since it will receive the electron beam uniformly, C
The excellent effect of greatly extending the life of the RT can be obtained.

[Example] Hereinafter, an example of the CRT screen burn-in prevention method according to the present invention will be described in detail with reference to the drawings. Figure 1 is C
This is an example of a circuit configuration when a CRT is used as a display device of a PU system.

In FIG. 1, l is a CPU, which is connected to various other elemental devices and input/output devices by path lines 2. In FIG. Fixed programs to be executed by the CPU system are recorded in a read-only memory (hereinafter referred to as ROM) 4, and processing information and data being processed are stored in a read/write memory (hereinafter referred to as RAM) 5. is temporarily stored. 6 is a graphic display controller for controlling a display device using a CRT, which processes signals sent from the ROM memory 4 and RAM memory 5 so that they can be displayed on the CRT, and also controls the CRT display device. Create command signals for control. 8 is R for kanji
OM, in which Kanji characters are recorded as 0.1 bit patterns. A dual port RAM 7 stores data transmitted from the graphic display controller 6 and the kanji ROM while displaying it on the CRT.

The number of pixels is 640x4 as a signal for displaying CRT.
Let us consider red, green, and blue for 00 as well as a horizontal synchronization signal and a vertical synchronization signal as an example.

The CPU prints 640x400 on the Cf1T every time the power is turned on.
The screen display area on the CRT is divided into 640 horizontal length and 400 vertical length.
Reference point “°A point” for screen display on the RT screen (
x.

y) is shifted and determined by the initial processing of the graphic display controller 6.

Next, an embodiment of the above-mentioned shifting method each time the power is turned on will be described with reference to the flowchart of FIG.

When the CPU is powered on, it checks the content N of an internal counter.

If the content of N is less than 4, add 1 to N.

The position (X, y) of point A predetermined by the contents of N is R
It is taken out from the OM and sent to the graphic display controller 6.

The graphic display controller 6 performs initial processing to prepare for displaying information sent from the RAM or the like at a predetermined position on the CRT, and then moves to the next step.

When checking the content N of the counter as described above, if the content of N is 4, the content of N is returned to 1. Therefore, the position of point A is obtained by storing the position under the condition of N=1 from the ROM. come.

The above steps are repeated every time the power is turned on, so CRT
The position displayed above will be shifted in four cycles as shown in FIG.

The value of N must be saved even when the power is turned off.

Figure 4 roughly shows the pixels on the CRT, but when N = 1, the image where the position of point A (x, y) is (xtyt) is (xtyt), and when N = 2, it is (X2, y2). ), when N=3, it shifts to the left (X3 y3), and when N=4, it shifts further to (X
4, y4) and returns to N=1, the character position also returns to its original position (xl, yl).

In the above description, N is set to 4 at the maximum, but the number of sliding positions does not necessarily need to be set to 4, and can be set to any number depending on the system.

Further, the method for shifting can be arbitrarily determined other than that explained in FIG. 4.

[Effects of the Invention] As explained above, according to the present invention, since the display position of a still image displayed on a CRT is not fixed, the same location of the fluorescent film of the CRT is continuously exposed to the electron beam. Since the surface of the fluorescent film is uniformly exposed to the electron beam without being exposed to electron beams, an excellent effect can be obtained in that the life of the CRT can be greatly extended.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment based on the present invention. FIG. 2 is a CRT screen diagram of an embodiment based on the present invention. FIG. 3 is a flow chart diagram of one embodiment based on the present invention. FIG. 4 is a pixel diagram of an embodiment based on the present invention. 1...CPU 2...Pass line 3...CRT 4...ROM 5...RAM 6...Graphic display control 7...Dual port RAM 8...Kanji ROM Figure 1

Claims (1)

[Claims] 1. In a pattern display system using a cathode ray tube controlled by a computer, a cathode ray tube screen characterized in that the display position of a still image displayed on the cathode ray tube is not fixed. Anti-seize method. 2. After the still image displayed on the cathode ray tube is cleared, the display address of the newly displayed still image on the cathode ray tube is set based on the display address of the still image before being cleared. 2. The method for preventing burn-in of a cathode ray tube screen according to claim 1, characterized in that the position is shifted.