JP2000200061A - Display device and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device and a control method thereof wherein a high brightness level can be achieved with a low electric consumption. SOLUTION: In this control method, each pixel 101 of a dot matrix consists of four pieces of light emitting elements emitting red, green, blue, and white, and when the brightness levels of the color signals for driving each of the red, green, and blue light emitting elements exceed a prescribed value, the white light emitting element is driven to emit light. Since high brightness can be achieved by making the newly arranged white light emitting element emit light, electric consumption is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a display device, and more particularly to a display device using a dot matrix and a control method thereof.

[0002]

2. Description of the Related Art A display device such as a plasma screen display using a dot matrix generally has a red color.
(R), green (G), and blue (B) realize color display by a dot matrix that constitutes one pixel by three elements that emit three primary colors.

[0003] The principle of the light emitting element is the same as the principle of the fluorescent tube. A fluorescent paint that emits light for R, G and B is applied to the inside of a pair of glass plates, and ultraviolet light is applied thereto to cause the fluorescent paint to emit light. ing.

[0004] Such colorization of a plasma display is usually realized by using an RGB color filter or an RGB phosphor. For example, JP-A-7-169403
In Japanese Patent Laid-Open Publication No. H11-207, full-color display is realized using RGB phosphors. In particular, when the green phosphor is composed of a mixture of the G phosphor and the B phosphor, the reproducibility of the white color is reduced.
Close to T (Cathode Ray Tube).

[0005]

However, even in the above-mentioned conventional configuration, since the luminance level is lower than that of a cathode ray tube CRT, an image is difficult to see in a bright place.
There is a need to further improve the brightness level. Further, it is also required to achieve high luminance with low power consumption.

An object of the present invention is to provide a display device capable of achieving a high luminance level with low power consumption and a control method thereof.

[0007]

According to the display device of the present invention, each pixel of the dot matrix has a red, green, blue,
And four light-emitting elements that emit white light. Since the luminance level of the pixel can be increased by the light-emitting element which emits white light, the pixel can be sufficiently used even in a surrounding high luminance place. Furthermore, compared to a conventional display device having a configuration of three elements of red, green, and blue,
High brightness levels can be achieved with low power consumption.

Further, in the display device according to the present invention, each of the pixels of the dot matrix includes four light-emitting elements for emitting red, green, blue, and white light, and red, green, and blue light-emitting elements. Control means for driving the light emitting element which emits white light to emit light when the luminance level of the color signal to be driven exceeds a predetermined value. The newly provided white light-emitting element emits light when the luminance level of the pixel exceeds a predetermined value, so that it can be used even in a bright place. In addition, since only one light-emitting element per pixel emits light, low power consumption is achieved. Power can be achieved.

[0009]

FIG. 1 is a pixel configuration diagram showing an embodiment of a display device according to the present invention. The display device 10 according to the present embodiment has four pixels of red, green, blue, and white per pixel 101.
It is composed of light emitting elements. Here, the light emitting element of each color is, for example, a plasma light emitting element, which may use a colored filter, or may emit light using the phosphor of each color as described above.

FIG. 2 is a circuit diagram showing an example of the display correction circuit according to this embodiment. The analog RGB signal is A /
The signal is converted into a digital signal by the D converter 201. A
The / D converter 201 includes a digital R signal S _R , a digital G signal
Luminance signal _{S G} and the digital B signal _{S B} level determining section 2
02 and output to adders 204 to 206, respectively.

[0011] luminance level determination section 202, as described later, and outputs the digital RGB signals _S R, generates a correction control signal _{S C} when the sum of _{S G} and _{S B} exceeds a predetermined value correction circuit 203 . The correction circuit 203 outputs a correction control signal S _C
Red correction signal _{C R,} a green correction signal _{C G,} blue correction signals _{C B,} and the white signal to generate a _{S W,} the red correction signal _{C R,} a green correction signal _{C G,} and the adder blue correction signal _{C B} 204 in accordance and outputs to -206, and outputs the white signal _{S W} to the display device 10. Note that the correction circuit 203
Each level of the B correction signals C _R , C _G and C _B and the white signal S
The level of _W can be adjusted. For example, RGB correction signals _C R, _{C G} and _{C B} by the digital RGB signals _S R, if each level of _{S G} and _{S B} is lowered a predetermined amount,
The level of the white signal S _W by raising a certain amount, can achieve the same luminance level lower power consumption.

[0012] Adder 204 outputs to the display device 10 the red signal by adding the digital R signal _{S R} and a red correction signal _{C R.} Similarly, the adder 205 adds the digital G signal _SG and the green correction signal _CG to generate a green signal to the display device 10.
Output to the adder 206 outputs to the display device 10 the blue signal by adding the blue correction signal C _B digital B signal S _B.

[0013] red signal obtained in this manner, green signal, blue signal and a white signal S _W is output to the display device 10, component red pixels, green, four light emitting elements of blue and white Light emission is performed at a light emission amount corresponding to the signal level of each color. The driving circuit itself for each light emitting element of the plasma display is well-known, and thus the description is omitted here.

The luminance level judging section 202 is as shown in Table 1.
U, digital RGB signal S_R, S _GAnd S_BTota
Value exceeds a fixed value (here, 180h in hexadecimal)
The correction control signal according to the RGB total value.
No. S_CAnd the correction circuit 203 outputs the correction control signal S_C
According to the white signal S_WTo change the level.

[Table 1]

[0015] By changing the level of such white signal S _W, it is possible to display with high luminance levels. In addition, since the luminance level can be increased only by increasing the amount of light emitted from one white light emitting element per pixel, higher power and higher luminance can be obtained than when simultaneously increasing the amount of light emitted from three RGB light emitting elements. You can get the display.

Further, the RGB compensation generated by the correction circuit 203 is performed.
Positive signal C_R, C_GAnd C_BRGB digital signal by
S_R, S_GAnd S_BLower each level, and
No. S _WBy increasing the level of the same brightness
Degree levels can also be achieved with lower power.
For example, the correction control signal S_CThe upper three digits of "111h"
In this case, RGB correction is performed, as shown in Table 2.
It is also possible to make adjustments.

[0017]

[Table 2]

[0018]

According to the present invention, by providing a white light emitting element in addition to the conventional three RGB light emitting elements, it is possible to realize a display with a high luminance level with low power. Further, since a high luminance level can be obtained with low power, it can be used in a bright place and can be used for a display device of a portable device.

[Brief description of the drawings]

FIG. 1 is a pixel configuration diagram showing one embodiment of a display device according to the present invention.

FIG. 2 is a circuit diagram illustrating an example of a display correction circuit according to the embodiment.

[Explanation of symbols]

 Reference Signs List 10 display device 101 pixel 201 A / D conversion unit 202 luminance level determination unit 203 correction circuit 204 to 205 adder

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Claims (7)

[Claims] 1. A display device using a dot matrix, wherein each pixel of the dot matrix has red, green, blue,
And a display device comprising four light-emitting elements that emit white light. 2. A display means comprising four light-emitting elements in which each pixel of a dot matrix emits red, green, blue, and white light, and a color signal for driving the red, green, and blue light-emitting elements, respectively. Control means for driving the light emitting element which emits white light to emit light when the luminance level exceeds a predetermined value. 3. The display device according to claim 2, wherein the control unit increases the light emission amount of the light emitting element that emits the white light according to a difference between the luminance level and the predetermined value. 4. The control unit increases a light emission amount of the light emitting element that emits white light according to a difference between the luminance level and the predetermined value, and responds to a difference between the luminance level and the predetermined value. 3. The display device according to claim 2, wherein the light emission amounts of the red, green and blue light emitting elements are reduced. 5. A method of controlling a display device in which each pixel of a dot matrix includes four light emitting elements that emit red, green, blue, and white light, respectively driving the red, green, and blue light emitting elements. A method for controlling a display device, comprising: calculating a luminance level of a color signal; and driving the light emitting element that emits the white light when the luminance level exceeds a predetermined value. 6. The method according to claim 5, wherein a light emission amount of the light emitting element that emits white light is increased according to a difference between the luminance level and the predetermined value. 7. A light-emitting element that emits the white light according to a difference between the luminance level and the predetermined value, and increases a light emission amount of the light-emitting element that emits the white light.
The method of controlling a display device according to claim 5, wherein the light emission amounts of the green and blue light emitting elements are reduced.