JPH0916126A - Full-color led panel - Google Patents

Abstract

PURPOSE: To provide an LED panel which can keep a display image at a high quality without change with time by renewing correction data for individual LEDs to be optimum even if the individual LEDs are aged different in degree. CONSTITUTION: An arithmetic means 5 calculates image data inputted externally and the correction data stored in a read/write memory 3 for correction to apply correction to the image data and correct the dispersion in the brightness of LED. And the content of the correction memory 3 can be renewed by using the same signal line as used in the input of the image data. Through this, high- quality display images are realized by uniforming the brightness of each LED having dispersion and the content can be easily renewed without exchanging the device of correction memory 3 and increasing the number of signal lines connected to the panel. As the results, quality deterioration of display images can be prevented from secular deterioration of LEDs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-color LED panel for displaying images of electronic devices such as televisions and personal computers.

[0002]

2. Description of the Related Art Conventionally, in a full-color LED panel in which a plurality of LEDs are arranged in a dot matrix and each dot is formed by selectively emitting light, the brightness of the plurality of LEDs forming each dot varies. As a result, there is a problem in that density unevenness or the like occurs in a display image, which leads to deterioration in quality, and various techniques have been proposed to solve this problem.

As such a conventional technique, for example, the brightness of each LED to be used is measured in advance, and only those which fall within a certain range are selected and used, so that the variation range is suppressed to a small level, and each measured in advance. Correction data for correcting the brightness of each LED to a constant value based on the brightness of the LED is stored in a memory for correction, and when displaying, the image data and the correction data are calculated to calculate the light emission time. There are known means for adjusting the brightness to a certain level by adjusting the brightness.

[0004]

However, the former technique cannot be used for LEDs whose brightness does not fall within a certain range, resulting in a poor yield and a significant cost increase. The brightness can be made uniform with respect to the variation, but with the passage of time, each LED deteriorates with time, and the degree of deterioration is also different for each LE.
Since there is a variation in D, there is no countermeasure against the problem that the luminance of each LED varies after a certain period of time and the quality of the display image deteriorates, so there is no choice but to replace the entire panel, which also increases the cost. Was a factor of.

Further, in the latter technique, it is necessary to replace the correction memory in order to cope with the deterioration of each LED over time. However, in reality, full color L
The ED panel is often installed in a very dangerous place to work, such as on the roof or wall of a building, and a full-color LED panel usually consists of 16 dots x 16 dots each. , A large number of these (30 vertically ×
Since a large screen is constructed by combining 40 horizontal sheets to about 1200 sheets), it is necessary to exchange a large number of correction memories, which requires a great deal of labor and cost. Therefore, conventionally, almost no countermeasure against deterioration over time has been taken, and the quality of the displayed image remains low.

[0006] Therefore, the present invention provides a full-color LED panel capable of keeping the quality of a display image high forever by updating the optimum correction data even if the degree of deterioration with time of each LED varies. With the goal.

[0007]

As a technical means for solving the above problems, the present invention provides an LED display unit in which a plurality of LEDs are arranged in a dot matrix and correction data representing the brightness information of each LED. Having a read-out and writable correction memory for storing, and an operation means for correcting the input image data according to the correction data, and uniformly correcting the brightness of each LED having a variation in brightness, Without replacing the memory device
The configuration is such that the contents of the correction memory can be updated. Further, the update data of the correction memory is transferred through the same signal line as the transfer of the display image data.

[0008]

According to the above-mentioned structure, each LED is changed with the passage of time.
Deterioration occurs over time, and the degree of deterioration also varies from LED to LED.
A full-color LED installed on the ground without replacing the device of the correction memory even for the brightness variation of D.
The correction data to be stored in the correction memory can be easily updated to the optimum value without increasing the number of signal lines connected from the control device of the panel, and the quality of the display image can be kept high forever.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. Here, for simplicity, it is assumed that one panel is composed of 4 dots × 4 dots,
The description will proceed assuming that four panels are used in combination in the lateral direction. FIG. 1 is a block diagram of a full-color LED panel according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an LED display unit in which each dot is a combination of red, green and blue LEDs in a dot matrix. A timing controller 2 outputs each control signal for controlling each operation timing in the panel according to signals (H, V, W, CLK) input from a control computer or a front panel (not shown). 3 for each LE
The brightness information of D is stored in the address corresponding to the dot position of each LED, and the correction data stored in the address specified by the Address signal output from the timing controller 2 is output. It is a correction memory. Reference numeral 4 denotes a signal SE output from the timing controller 2 indicating whether the data input via the bus Din is to be transferred to the next panel, image data for display, or rewriting data for changing the contents of the correction memory.
According to L, the data to be transferred to the next panel is the bus Dout, and the image data for display is the bus Dout.
It is a data selector that outputs to sel and to the bus Dwr if it is rewriting data for changing the contents of the correction memory.

Reference numeral 5 calculates the image data for display input via the bus Dsel and the correction data input from the correction memory 3 via the bus Dh, and the calculated result is used as corrected image data in the bus. The calculating means 6 for outputting to Dcul is corrected by the calculating means 5 so as to make the brightness of each LED uniform, and the bus Dcu is composed of 9 bits in the order of RGB.
The corrected image data input via 1 is held while being sequentially shifted, and the fact that the data for one panel is held is indicated by the timing controller 2 from the signal line HSY.
When confirmed by the signal input through NC, the signal lines Dr, D are separated into R, G, B respectively.
shift means for serially outputting to g and Db, 7
Represents the image data input from the shift means 6 via the signal line Dr, and the image data input via the signal line CONr (CL
There are three types of signals, Kr, LAr, and STRr.
Then, for the sake of simplicity, it is shifted and held according to CONr.
This is a red driver that outputs to a red LED (not shown) in the ED display unit 1 to emit light.

Reference numeral 8 denotes three kinds of signals (CLKg, LAg and STRg) which are image data inputted from the shift means 6 via the signal line Dg and inputted via the signal line CONg. For the green LED in the LED display unit 1 according to the STRg signal.
A green driver (not shown) for emitting light, and 9 is a signal (CLK for inputting image data input from the shift means 6 through the signal line Db to the image data input through the signal line CONb).
b, LAb, and STRb are three types of signals, but they are shifted and held in accordance with the STRb signal in FIG.
This is a blue driver that outputs to a blue LED (not shown) in the D display unit 1 to emit light.

Full-color LED constructed as described above
The operation of the panel will be described below. FIG. 2 is a timing chart when displaying an image of a full-color LED panel in one embodiment of the present invention. Signal V in FIG.
When the signal H changes to "0" when is "0", the timing controller 2 is in the mode for displaying an image.
Judge. When the image display mode is determined, the data input via the bus Din in synchronization with the fall of the signal H is transferred by the data selector 4 to the buses Dout and Dsel.
And is input to the calculation means 5. At this time, the input image data is input in the order of red, green, and blue in the leftmost dot on the first line, and then red, green in the second dot from the left on the first line, In the order of blue, the data of each line is similarly input thereafter.

Here, at the address 0 of the correction memory 3, an LED
The correction data for the red LED of the leftmost dot on the first row of the panel is the correction data for the green LED of the leftmost dot of the first row on the first address, and the first row is on the second address. The correction data for the blue LED of the leftmost dot of the eye is stored. After that, the second dot from the left, red, green, and blue are sequentially stored in this order.

From the time when the signal H changes to "0", the signal C
Since the timing controller 2 starts counting up the address signal output to the bus Address in synchronization with the rising edge of LK, the image data R1 for the red LED in the leftmost dot of the first row is the bus Dsel.
At the same time that the data is inputted to the calculating means 5 via 8 bits from the correction memory 3, the correction data H0 for the red LED in the leftmost dot in the first row stored in the address 0 is stored.
Is input to the arithmetic means 5 in 8 bits via the bus Dh.

The operation means 5 multiplies the image data input by 8 bits each with the correction data, and the upper 9 bits of the 16 bits of the operation result are the corrected image data on the bus D.
data for red in the shift means 6,
Separated into green data and blue data, and further 9
The bit data is converted into serial data and output to the drivers 7, 8, 9 for each color, and the LED display unit 1 is caused to emit light to display the image of the first row. At the time when the image on the first line is displayed (red, green, blue, 4 dots each, total 4
The signal H returns to "1" at the time point when eight pieces of data have been transferred, indicating the end of the display cycle of the first row. After that, data is retained and displayed continuously in the first line during the period from the display cycle of the second line to the display cycle of the fourth line. In addition, the same cycle is displayed for the second to fourth lines,
The full-color LED panel is displayed on the entire surface.

FIG. 3 is a timing chart when updating the contents of the correction memory of the full-color LED panel in one embodiment of the present invention. In FIG. 3, the timing controller 2 determines that the mode is a mode in which the correction data is updated when the signal H changes to “0” when the signal V is “1”. When the correction data update mode is determined, the bus Di is synchronized with the falling of the signal W while the signal W is "0".
The data input via n is distributed to the buses Dout and Dwr by the data selector 4 and directly input to the correction memory 3 without passing through the arithmetic means 5. At this time,
The order of the correction data to be input is the same as in the image display mode. The correction data for red, the correction data for green, and the correction data for blue in the leftmost dot on the first line are input in that order. The correction data of is input.

The address signal input via the bus Address is incremented by 1 each time the signal W changes to "0", and the signal NWR is 1 when the signal W is 1.
A pulse of "0" is output once each time it becomes "0". By repeating the above cycle for the number of LED dots, the content of the correction memory 3 is updated by one address each time the signal W becomes "0", and when the cycle is repeated 768 times, the correction of the correction memory 3 is corrected. All data is updated.

[0018]

According to the present invention, each L is changed over time.
The deterioration of ED occurs over time, and the degree of deterioration also varies among LEDs, so even if the brightness variation of each LED appears after a certain period of time, it is installed on the ground without replacing the device of the correction memory. Full color L
The control device of the ED panel can easily update the correction data stored in the correction memory to the optimum value without increasing the number of signal lines connected, and the quality of the display image can be kept high forever.

[Brief description of the drawings]

FIG. 1 is a block diagram of a full-color LED panel according to an embodiment of the present invention.

FIG. 2 is a timing chart when displaying an image of a full-color LED panel according to an embodiment of the present invention.

FIG. 3 is a timing chart when updating the contents of the correction memory of the full-color LED panel in the embodiment of the present invention.

[Explanation of symbols]

 1 LED Display Unit 2 Timing Controller 3 Correction Memory 4 Data Selector 5 Computing Means 6 Shifting Means 7 Red Driver 8 Green Driver 9 Blue Driver

Claims (2)

[Claims] 1. An LED display unit in which a plurality of LEDs are arranged in a dot matrix, a readable and writable correction memory for storing correction data representing luminance information of each LED, and input according to the correction data. It is characterized in that it has an arithmetic means for correcting image data, uniformly corrects the brightness of each LED having variations in brightness, and updates the contents of the correction memory without replacing the device of the memory. Full color LED panel. 2. The full-color LED panel according to claim 1, wherein the update data of the correction memory is transferred through the same signal line as the transfer of the display image data.