JPH04359292A - Automatic adjusting device for screen brightness - Google Patents

Abstract

PURPOSE:To keep a constant brightness of a computer output display device at all the time despite the varying amount of displayed materials which otherwise cause varying brightness. CONSTITUTION:The output data from a computer 26 are transmitted to a VRAM 17 as the data to be displayed through a CPU bus 16, a character generator 20 is accessed, a transforming unit 21 converts the data to display dot data and the data are displayed on a CRT 19 through a brightness correcting circuit 24. Nearby brightness of the CRT is received by a light quantity sensor 3 whose output is added to the above mentioned brightness correcting circuit 24 thus, it is controlled to keep the brightness of the display screen constant despite the varying amount of displayed characters.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic screen brightness adjustment device used in a display device for displaying computer output data.

0002

2. Description of the Related Art In recent years, self-luminous display devices such as cathode ray tubes (hereinafter abbreviated as CRT) and plasma displays are often used as devices for outputting computer data.

However, in such conventional display devices, the brightness of each display is generally not varied, regardless of the amount of display on the screen.

0004

However, in the conventional display device described above, when the amount of display is small, the entire display screen is dark, and conversely, when the amount of display is large, the entire screen is bright. Therefore, when the amount of display on the screen is changed, the brightness of the screen changes significantly, causing a problem in that the viewer must frequently open and close the pupils of his or her eyes. Staring at such display screens for long periods of time can cause eye fatigue.
For viewers, it is desirable that the screen they are staring at always has a constant brightness.

[0005] Furthermore, when the amount of display is large, a blooming phenomenon occurs on the display screen, causing the displayed characters to smudge and reduce the resolution.

[0006] Furthermore, it is more desirable that the total brightness including the amount of external light incident on the display screen be constant.

According to the present invention, the brightness of the screen does not change even if the display capacity on the screen changes, and furthermore, by keeping the brightness of the display screen constant even when the amount of external light changes, the viewer can An object of the present invention is to provide a display device that prevents the pupils of the eyes from opening and closing frequently, thereby reducing eye fatigue.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention, in a display device that displays data, calculates the total amount by adding the amounts displayed on the display screen using a computer. Depending on the value, the brightness of the screen is increased when the amount of display is small, and the brightness of the screen is decreased when the amount of display is large.

[0009]

[Operation] With the above-described structure, the present invention can maintain uniform brightness of the entire screen even if the display amount changes.

0010

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, display characters 2 are displayed on a CRT screen 1 that displays output data from a computer, and a light amount sensor 3 is arranged to input the amount of outside light 4 around the CRT. ing. Furthermore, as shown in FIG. 2, the output data from the computer 26 is
The display data is sent to the VRAM 17 through the bus 16, and after being written to the VRAM 17, the data is read out by the CRT timing controller 18 and accesses the character generator (hereinafter abbreviated as CG) 20.
The data is converted into display dot data by the parallel/serial converter 21, passed through the brightness correction circuit 24, and displayed on the CRT 19. Further, the brightness around the CRT is received by the light amount sensor 3, passes through a comparator 25, and is then added to the brightness correction circuit 24 together with an output signal from a port 23 provided on the CPU bus 16. There is.

Regarding the display device for output data from a computer configured as described above, the operation of the automatic display screen brightness adjustment device will be described. First, in Figure 1, C
When display characters 2 are displayed on RT screen 1, when the number of display characters 2 is small, the display brightness of the characters is increased and displayed, and when the number of display characters 2 is large, the display brightness of the characters is lowered and displayed. By doing so, the brightness of the entire CRT screen 1 is made constant. Next, in Figure 2, C
The display data sent from the PU bus 16 is stored in the VRAM 17.
The written data is read out from the CRT timing controller 18 according to the display timing of the CRT 19, and the CG 20 is accessed by this data. The data from the CG 20 is converted into display dot data by the parallel/serial converter 21 and becomes a video signal, which is sent to the CRT 19 and becomes a bright spot on the CRT display screen 1. As a method of changing the brightness of the display screen, a port 23 is provided on the CPU bus 16, and the data of the port 23 is sent to the brightness correction circuit 24 having the circuit shown in FIG. The brightness is changing. The display amount displayed on the screen here is determined by counting the character codes in the VRAM 17. Next, one embodiment of the luminance correction circuit 24 will be described using FIG. 3. As shown in FIG. 3, the signals 12, 13, 14, 15 are respectively connected to the buffer gate 6, and their outputs are connected to the DC voltage from the resistors 8, 9, 10, 11 and the resistor 7 connected in series with the power supply voltage. is added and a video signal 5 is output. Here, for the buffer gate 6, an open collector TTL such as 7406 is used, and the input signal is high level (H) or low level (L), or the level (X ) and by appropriately selecting the values of the resistors 7, 8, 9, 10, and 11, a video signal 5 having 16 levels of brightness is output. For example, C that can display a total of 160 characters.
When considering RT screen 1, it becomes as shown in Table 1.

[0013]

[Table 1]

[0014] This (Table 1) shows that the display capacity displayed on the CRT screen 1 is divided into 8 stages from 1 character to 160 characters, and when the amount of external light (CRT ambient light) is high and low. , signals 12,1 of the example circuit shown in FIG.
3, 14, 15 and the brightness on the CRT display screen 1.

As a result of the above, the brightness on the CRT display screen 1 can be maintained almost constant as viewed from the viewer.

(Embodiment 2) A second embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the amount of external light 4 is measured using an external light amount sensor 3 installed around a CRT display screen 1 of a display device that displays data from a computer.
The result is reflected in the brightness of the characters 2 displayed on the CRT screen 1. By arranging them as described above, the brightness on the CRT display screen 1 can be kept constant even when the amount of external light 4 changes. Furthermore, as shown in FIG. 2, the signal obtained from the external light amount sensor 3 is compared in magnitude by a comparator 25, and the resulting data is input to the brightness correction circuit 24. The operation of the brightness correction circuit 24 is exactly the same as that in the first embodiment, so a description thereof will be omitted. As shown in the first embodiment, the output of the brightness correction circuit 24 is applied to the CRT 19 and the CRT screen brightness is corrected as shown in Table 1.

[0018]

[Effects of the Invention] As is clear from the above embodiments, according to the present invention, when the display capacity is small, the brightness of the screen is adjusted so that the brightness of the screen does not change even if the display capacity on the screen changes. By increasing the brightness of the screen and reducing the brightness when the amount of display is large, and by keeping the brightness of the display screen constant even when the amount of external light changes, the pupil of the viewer's eyes Therefore, it is possible to provide an excellent display device that prevents the display from being opened and closed frequently, thereby reducing eye fatigue of the user.

[Brief explanation of the drawing]

[Fig. 1] A block diagram of an embodiment of the present invention including a CRT display screen and an external light amount sensor.

FIG. 2 is a block diagram of an automatic screen brightness adjustment device according to an embodiment of the present invention.

FIG. 3: Brightness correction circuit diagram in an embodiment of the present invention

[Explanation of symbols]

1 CRT display screen 2 Display characters 4. Amount of external light 3 Light amount sensor 19 CRT 26 Computer

Claims (2)

[Claims] [Claim 1] When the display amount is small, the screen brightness of the display screen is increased according to the value calculated by adding the display amount displayed on the display screen of the display device by a computer, and the display amount is increased. An automatic screen brightness adjustment device that reduces screen brightness when there is a lot of screen brightness. 2. The screen brightness according to claim 1, further comprising a light amount sensor that measures the amount of outside light, and a function of correcting the brightness adjustment of the display screen based on the calculation result according to the intensity of the amount of outside light. Automatic adjustment device.