JP3202816B2 - Display device and control method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat display device and a control method thereof, and more particularly to a display device capable of making the chromaticity the same on a display when mixing colors and reducing color unevenness when mixing colors, and its control. About the method.

[0002]

2. Description of the Related Art In recent years, flat display devices have been used for display units of personal computers in place of display devices of CRTs, and wall-mounted display devices indoors and large display devices outdoors. Is used.

Conventionally, some flat type display devices include a light emitting diode (LED) panel, a plasma display panel (PDP), a liquid crystal display (LCD), a fluorescent display panel, and the like.

Hereinafter, a light emitting diode (LED) panel will be described as a specific example of a conventional flat type display device. For example, a single-color light emitting diode (LED) panel has a red or green light emitting diode of 16 × 1.
There is a 16 × 16 LED dot matrix display arranged in a matrix of six.

Next, a light emitting diode (L
The ED) panel will be described with reference to FIG. FIG.
FIG. 3 is a schematic diagram of a display unit that forms one character on a display panel. As shown in FIG. 4, the display unit of the display panel in the display device has, for example, a red light emitting diode 21 (R) and a green light emitting diode 22 (G) of 16 dots per raster alternately arranged for each raster. Matrix-type LED dot matrix display with 16 × 16 red light emitting diodes and one green light emitting diode
6 × 16 pixels are arrayed, but alternately red,
Since the green light emitting diode is arranged, the light emitting diode is
A total of 16 × 32 nodes are arranged. Either the red light emitting diode 21 or the green light emitting diode 22 emits light to perform a red or green monochromatic display, and both the red light emitting diode 21 and the green light emitting diode 22 emit light. Red light emitting diode 21 and green light emitting diode
The mixed color display of yellow is performed by the two-color lighting of the display 22.

Next, the configuration of the conventional display device will be described with reference to FIG. FIG. 5 is a block diagram showing a configuration of a conventional display device using a light emitting diode (LED) panel capable of performing mixed color display. As shown in FIG. 5, the display device comprises:
Data for emitting a red light emitting diode (R-DAT)
Shift register 1a for serial / parallel conversion of A)
And data (G-DA) for emitting a green light emitting diode.
TA) shift register 1 for serial / parallel conversion
b, a buffer 2a for storing parallel-converted R-DATA, a buffer 2b for storing parallel-converted G-DATA, and a plurality of light emitting diodes as shown in FIG.
And a driver 3 for outputting the data stored in the buffers 2a and 2b to the display unit 4.
a, 3b, a pulse generator 7 for outputting a pulse of a specific pulse width, and a pulse generator 7 for a specific raster light emitting diode in the display unit 4 according to an address instruction signal.
And a driver 8 that outputs a lighting pulse based on the pulse from the controller 8.

Further, a specific configuration of the above-mentioned conventional display device will be described with reference to FIG. FIG. 6 is a schematic configuration diagram of a conventional display device using a light emitting diode (LED) panel capable of performing mixed color display. As shown in FIG. 6, the display device includes 16-bit shift registers 1a and 1b for taking in data DA up to N digits in synchronization with a clock CL and a latch signal LA generated every N digits. 1a,
Buffers 2a and 2b for latching data of 1b, drivers 3a and 3b for outputting data latched by the buffers 2a and 2b, and a light emitting diode (LED) 9 is turned on by the output of the driver. 16x to display characters etc.
A 32 dot LED dot matrix 4 ', a pulse generator 7 for outputting a pulse of a specific pulse width, and a lighting pulse based on a pulse from the pulse generator 7 according to an address instruction signal. And a driver 8 for outputting the data. The display unit 4 shown in FIG. 5 corresponds to the LED dot matrix 4 'shown in FIG.

Next, the operation of the above-mentioned conventional display device will be described with reference to FIG. When the shift register 1a (shift register 1b) takes in the R-DATA (G-DATA) and the latch signal LA is input to the buffer 2a (buffer 2b), the R-DATA (G-DATA) is shifted to the shift register 1a ( Shift register 1b) to buffer 2a
(Buffer 2b), the serial / parallel conversion is performed, and the driver 3a (driver 3b)
(Buffer 2b) outputs R-DATA (G-DATA) to the LED dot matrix 4 '.

On the other hand, when the pulse generator 7 supplies a pulse to the driver 8, the driver 8 outputs a lighting pulse to a specific raster of the LED dot matrix 4 'according to the address instruction signal. The lighting pulse given to the raster and R
A light emitting diode (L
ED) 9 is turned on, all rasters are turned on, and the LED dot matrix 4 'displays characters and the like.

A display device having a display screen (LED panel) as shown in FIGS. 7A and 7B by combining a plurality of display units 4 based on the display device shown in FIGS. Was formed.

[0011]

However, in the above-described conventional display device and its control method, chromaticity variation actually occurs in each of the display units in FIG. 5 due to various manufacturing problems. In addition, there is a problem in that the chromaticity variation between the display units is conspicuous, and color unevenness occurs on the entire display panel.

The present invention has been made in view of the above circumstances, and solves the chromaticity variation among the display units at the time of mixed-color display by performing brightness adjustment for each color for each display unit, thereby causing a display panel. It is an object to provide a display device capable of reducing color unevenness and a control method thereof.

[0013]

According to a first aspect of the present invention, there is provided a display device comprising a plurality of types of light emitting diodes, wherein the plurality of types of light emitting diodes are provided. And a display unit for simultaneously displaying the plurality of types of light-emitting diodes, and data for causing the respective light-emitting diodes of the display unit to emit light temporarily. A buffer to be stored, a first driver connected to each of the buffers to output the data to the display unit, and a set value for determining a pulse width of a lighting pulse for each color in the display unit are set. A set value buffer, a pulse generator for generating a pulse having a pulse width determined by the set value of the set value buffer, and a pulse width of the pulse from the pulse generator. It is characterized by a second driver for outputting the lighting pulse to the display unit.

According to a second aspect of the present invention, there is provided a control method of a display device according to the first aspect, wherein a set value for determining a lighting pulse width is previously set in a set value buffer. The first driver outputs the data temporarily stored in the buffer to the display unit, the pulse generator reads the set value from the set value buffer, and outputs a pulse having a pulse width based on the set value to the second driver. And a second driver outputs a lighting pulse having a pulse width according to the pulse to the display unit.

[0015]

According to the first aspect of the present invention, the set value buffer in which the set value for determining the pulse width of the lighting pulse is set, the set value in the set value buffer is read, and the pulse having the pulse width based on the set value is read. Since the pulse generator for outputting to the second driver is provided for each type of light emitting diode, a lighting pulse according to the pulse width of the pulse from each pulse generator is displayed from the second driver. It is output to the unit and can emit light at an appropriate luminance for each type of light emitting diode, and the luminance for each type of light emitting diode is adjusted by changing the set value of the set value buffer.
In a display panel including a plurality of display units, a variation in chromaticity between display units that occurs at the time of mixed color display can be solved, and color unevenness of the display panel can be reduced.

According to the second aspect of the present invention, the set value for changing the luminance of the light emitting diode for each type of light emitting diode is set in the set value buffer, and the pulse generator stores the set value from the set value buffer. 2. The display device according to claim 1, wherein the read driver outputs a pulse having a pulse width determined by the set value to the second driver, and the second driver outputs a lighting pulse according to the pulse width of the pulse to the display unit. Since the control method is adopted, the luminance of each type of light emitting diode is adjusted by changing the set value of the set value buffer, and the color between the display units generated at the time of mixed color display on the display panel including a plurality of display units. It is possible to reduce the variation in the degree and reduce the color unevenness of the display panel.

[0017]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration block diagram of a display device according to an embodiment of the present invention. As shown in FIG. 1, in the display device of the present embodiment, a shift register 1a for serial / parallel conversion of data (R-DATA) for emitting a red light emitting diode and a green light emitting diode are emitted. A shift register 1b for serial / parallel conversion of data (G-DATA), and a R-DATA for parallel conversion
Buffer 2a for temporarily storing the G
A buffer 2b for temporarily storing DATA, a display unit 4 comprising a plurality of light emitting diodes, a buffer 2a,
Drivers 3a and 3b for outputting data temporarily stored in the display unit 4 to the display unit 4, a set value buffer 6a for storing a luminance set value of a red light-emitting diode, and a luminance set value of a green light-emitting diode Value buffer 6b in which is stored
A pulse generator 5a that outputs a pulse having a pulse width corresponding to the set value set by the set value buffers 6a and 6b.
5b and drivers 8a and 8b for outputting a lighting pulse to a light emitting diode of a specific raster according to an address instruction signal.
It is composed of

The shift register 1a performs serial / parallel conversion of R-DATA.
DATA is temporarily stored. Similarly, the shift register 1b performs serial / parallel conversion of G-DATA, and temporarily stores G-DATA in a buffer 2b.

The driver 3a converts the R-DATA temporarily stored in the buffer 2a into a display unit 4 with a high / low voltage.
Output to the red light emitting diode. Similarly,
The driver 3b uses the GD temporarily stored in the buffer 2b.
ATA is output to the green light emitting diode of the display unit 4 at a high / low voltage.

Next, the pulse generator 5 and the set value buffer 6, which are characteristic parts of this embodiment, will be specifically described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the pulse generator 5 and the set value buffer 6 in the characteristic part of the present embodiment. FIG.
As shown in (1), the pulse generator 5 is basically composed of a counter, receives a trigger signal and a clock (CK), reads a set value set in the set value buffer 6, and turns on the set value when the trigger signal is turned on. The counter is counted, divided by CK, and a pulse having a pulse width corresponding to the set value is output.

The set value buffer 6 is composed of a RAM or the like, and receives a luminance set value from a user or the like, temporarily stores the set value, and is connected to the pulse generator 5. This set value determines the width of the pulse created by the pulse creating section 5.

The operation of the pulse generator 5 and the set value buffer 6 according to the present embodiment will be described. A user or the like sets a luminance set value in the set value buffer 6 in advance, and then triggers the pulse generator 5. When a signal is input, the set value is read from the set value buffer 6, counted by CK using the set value, and a pulse having an arbitrary pulse width is output.

For example, if the natural numbers a and b satisfying a> b are set in the set value buffer 6 as set values, the pulses corresponding to the set value a are counted as shown in the timing chart of FIG. The pulse having a pulse width corresponding to the number a, and the pulse corresponding to the set value b have a pulse width corresponding to the count number b as shown in the timing chart of FIG. 3B.

Therefore, as can be seen from the timing charts of FIGS. 3A and 3B, the pulse width of the pulse output from the pulse generator 5 is set to the luminance set value set by the set value buffer 6. For example, if the green color emitted from the green light-emitting diode is dark during mixed color display, the luminance of the green light-emitting diode can be reduced by decreasing the set value of the set value buffer 6b. That is, an appropriate chromaticity can be obtained at the time of mixed color display.

The drivers 8a and 8b output a lighting pulse to a specific raster of the display unit 4 based on a pulse having a pulse width of the pulse generators 5a and 5b in accordance with the address instruction signal. DATA
(G-DATA) causes the light emitting diode to emit light, and all rasters are turned on for display.

Next, a control method in the display device of this embodiment will be described. When characters and the like are actually mixed-color displayed on a display panel including a plurality of display units, color unevenness occurs on the display panel. This is because, when comparing the same mixed color emitted by each display unit, chromaticity variation appears for each display unit. Therefore, in the display device of the present embodiment, the display unit having chromaticity variation is checked, and the luminance setting value is appropriately changed for the display unit so that the chromaticity of the display unit becomes uniform. This is to adjust the color unevenness of the display panel during mixed color light emission.

More specifically, in FIG. 1, for example, when the display unit emits yellow light (a mixed color light emission of red and green) and the red color is light, a driver 8a for emitting a red light emitting diode emits a lighting pulse. A larger set value can be set in the set value buffer 6a to increase the pulse width so that the red color becomes darker. For example, when the display unit emits yellow light and green is dark, a smaller set value is set in the set value buffer 6b so that the pulse width of the lighting pulse output by the driver 8b that emits the green light emitting diode becomes smaller. To make the green color lighter.

According to the display device of this embodiment and its control method, the set value buffer 6 corresponding to each display unit 4
If the setting values of a and 6b are reduced (increased), it is possible to adjust the luminance for each color to be decreased (increased) for each display unit. There is an effect that it is possible to preferentially solve the chromaticity variation among the display units at the time of color mixing, and to reduce color unevenness that occurs on the display panel.

[0029]

According to the first aspect of the present invention, the set value buffer in which the set value for determining the pulse width of the lighting pulse is set, and the set value of the set value buffer is read to set the pulse width based on the set value. Since the pulse generator for outputting a pulse to the second driver is a display device provided for each type of light emitting diode, a lighting pulse according to the pulse width of the pulse from each pulse generator is generated by the second driver. To the display unit to emit light with appropriate luminance for each type of light emitting diode, and adjust the luminance for each type of light emitting diode by changing the set value in the set value buffer. In addition, there is an effect that it is possible to solve the chromaticity variation between the display units that occurs at the time of the mixed color display in the display panel including a plurality of display units, and to reduce the color unevenness of the display panel.

According to the second aspect of the present invention, the set value for changing the luminance of the light emitting diode for each type of light emitting diode is set in the set value buffer, and the pulse generator stores the set value from the set value buffer. 2. The display device according to claim 1, wherein the read driver outputs a pulse having a pulse width determined by the set value to the second driver, and the second driver outputs a lighting pulse according to the pulse width of the pulse to the display unit. Since the control method is adopted, the luminance of each type of light emitting diode is adjusted by changing the set value of the set value buffer, and the color between the display units generated at the time of mixed color display on the display panel including a plurality of display units. There is an effect that the unevenness of the degree can be solved and the color unevenness of the display panel can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a display device according to an embodiment of the present invention.

FIG. 2 is a configuration block diagram of a characteristic portion of the present embodiment.

FIG. 3 is a timing chart of a pulse from a pulse generator according to the present embodiment.

FIG. 4 is a schematic view of a display unit of a conventional LED panel.

FIG. 5 is a configuration block diagram of a conventional display device.

FIG. 6 is a schematic configuration diagram of a conventional display device.

FIG. 7 is a schematic view of a conventional LED panel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Shift register, 2 ... Buffer, 3 ... Driver, 4 ... Display unit, 5 ... Pulse generator, 6 ...
Set value buffer, 7: pulse generator, 8: driver, 9: light-emitting diode (LED), 21: red light-emitting diode, 22: green light-emitting diode

Continuation of front page (56) References JP-A-2-214893 (JP, A) JP-A-4-97387 (JP, A) JP-A-1-266595 (JP, A) JP-A-6-19425 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G09G 3/14 G09G 3/20 G09G 3/32

Claims (2)

(57) [Claims] 1. A display unit comprising a plurality of types of light-emitting diodes, wherein the display unit performs color-mixed display by causing the plurality of types of light-emitting diodes to emit light simultaneously, and a plurality of types of light-emitting diodes corresponding to the plurality of types of light-emitting diodes. A buffer for temporarily storing data for causing each light-emitting diode of the display unit to emit light, and a first buffer connected to each of the buffers and outputting the data to the display unit. A driver and a set value buffer in which a set value for determining a pulse width of a lighting pulse for each color in the display unit is set;
A pulse generator configured to generate a pulse having a pulse width determined by the set value of the set value buffer; and a second driver configured to output a lighting pulse according to a pulse width of the pulse from the pulse generator to the display unit. A display device comprising: 2. The display device according to claim 1, wherein a set value for determining a lighting pulse width is previously set in a set value buffer, and the first driver outputs data temporarily stored in the buffer to the display unit. A pulse generation unit that reads the set value from the set value buffer, outputs a pulse having a pulse width based on the set value to a second driver, and outputs a lighting pulse having a pulse width according to the pulse to the second driver. Output to the display unit.