Display device and control method thereof

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

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】

[Conventional technology]

A display device such as a plasma screen display using a dot matrix generally uses a dot matrix in which one pixel is composed of three elements that emit three primary colors of red (R), green (G), and blue (B). Achieves color display.

【0003】

The principle of the light emitting element is the same as that of the fluorescent tube, and the fluorescent paint that emits light to R, G, and B is applied to the inside of a pair of glass plates, and the fluorescent paint is made to emit light by irradiating the inside with ultraviolet rays.

【0004】

Colorization of such a plasma display is usually realized by using an RGB coloring filter or an RGB phosphor. For example, Japanese Patent Application Laid-Open No. 7-169403 realizes full-color display using an RGB phosphor. In particular, by composing the green phosphor with a mixture of G and B phosphors, the reproducibility of white is brought closer to that of a CRT (Cathode Ray Tube).

【0005】

[Problems to be Solved by the Invention]

However, even in the above-mentioned conventional configuration, since the brightness level is lower than that of the CRT CRT, it becomes difficult to see the image in a place where the surroundings are bright, and it is required to further improve the brightness level. Further, it is required to achieve high brightness with low power consumption.

【0006】

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】

[Means for solving problems]

The display device according to the present invention is characterized in that each pixel of the dot matrix is composed of four light emitting elements that emit red, green, blue, and white light. Since the brightness level of the pixel can be increased by the light emitting element that emits white light, it can be sufficiently used even in a place where the surrounding brightness is high. Further, a high luminance level can be achieved with low power consumption as compared with a conventional display device having a configuration of three elements of red, green, and blue.

【0008】

Further, in the display device according to the present invention, each pixel of the dot matrix drives a display means including four light emitting elements that emit red, green, blue, and white light emitting elements, and red, green, and blue light emitting elements, respectively. It is characterized by comprising a control means for driving a light emitting element that emits white light to emit light when the brightness level of the color signal exceeds a predetermined value. The newly provided white light emitting element emits light when the brightness level of the pixel exceeds a predetermined value, so that it can be used even in a bright place, and moreover, only one light emitting element is emitted per pixel, so that the consumption is low. Power can be achieved.

【0009】

BEST MODE FOR CARRYING OUT THE INVENTION

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

【0010】

FIG. 2 is a circuit diagram showing an example of a display correction circuit according to the present embodiment. The analog RGB signal is converted into a digital signal by the A / D converter 201. The A / D converter 201 is a digital R signal S._R, Digital G signal S_GAnd digital B signal S_BIs output to the luminance level determination unit 202 and is output to the adders 204 to 206, respectively.

【0011】

The luminance level determination unit 202 determines the digital RGB signal S, as will be described later._R, S_GAnd S_BCorrection control signal S when the total of_CIs generated and output to the correction circuit 203. The correction circuit 203 is the correction control signal S._CAccording to the red correction signal C_R, Green correction signal C_G, Blue correction signal C_B, And white signal S_WGenerates a red correction signal C_R, Green correction signal C_G, And blue correction signal C_BIs output to the adders 204 to 206, respectively, and the white signal S_WIs output to the display device 10. The correction circuit 203 uses the RGB correction signal C._R, C_GAnd C_BEach level and white signal S_WIt is possible to adjust the level of. For example, RGB correction signal C_R, C_GAnd C_BBy digital RGB signal S_R, S_GAnd S_BWhite signal S when each level of_WThe same brightness level can be achieved with lower power consumption by increasing the level of.

【0012】

Adder 204 is a digital R signal S_RAnd red correction signal C_RAnd are added to output a red signal to the display device 10. Similarly, adder 205 is a digital G signal S_GAnd green correction signal C_GAnd are added to output a green signal to the display device 10, and the adder 206 is a digital B signal S._BAnd blue correction signal C_BAnd are added to output a blue signal to the display device 10.

【0013】

The red signal, green signal, blue signal and white signal S thus obtained._WIs output to the display device 10, and the four light emitting elements of red, green, blue, and white constituting each pixel are made to emit light at the amount of light emission corresponding to the signal level of each color. Since the drive circuit itself of each light emitting element of the plasma display is well known, the description thereof will be omitted here.

【0014】

As shown in Table 1, the luminance level determination unit 202 sets the digital RGB signal S._R, S_GAnd S_BWhen the total value of is exceeded a certain value (here, 180h in hexadecimal display), the correction control signal S is adjusted according to the RGB total value._CThe correction circuit 203 changes the correction control signal S._CAccording to white signal S_WChange the level of.

[table 1]

<img file="JP2000200061A_D0001.tif" />【0015】

Thus the white signal S_WBy changing the level of, it is possible to display with a high brightness level. Moreover, since the brightness level can be increased only by increasing the light emission amount of one white light emitting element per pixel, the light emission amount of three RGB light emitting elements can be increased at the same time with lower power consumption and higher brightness. You can get the display.

【0016】

Further, the RGB correction signal C generated by the correction circuit 203_R, C_GAnd C_BRGB digital signal by S_R, S_GAnd S_BDecrease each level of, and white signal S_WIt is also possible to achieve similar brightness levels with lower power by increasing the level of. For example, the correction control signal S_CIf the upper 3 digits of are "111h", RGB correction is performed, and it is possible to make adjustments as shown in Table 2.

【0017】

[Table 2]

<img file="JP2000200061A_D0002.tif" />【0018】

[Effect of the invention]

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

[Simple explanation of drawings]

[Figure 1]

It is a pixel block diagram which shows one Embodiment of the display device by this invention.

[Figure 2]

It is a circuit diagram which shows an example of the display correction circuit in this embodiment.

[Explanation of symbols]

10 Display device 101 pixels 201 A / D converter 202 Brightness level judgment unit 203 Correction circuit 204 ~ 205 adder