JP3268001B2 - LED dot matrix type display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED dot matrix type display device capable of displaying a high quality image which can be used for displaying an image of a television receiver, for example.

[0002]

2. Description of the Related Art In such an LED dot matrix type display device, it is necessary to make the luminance of a large number of LEDs constituting each dot as uniform as possible in order to obtain high quality image. Take steps. That is, C.I. O. B
In a (chip-on-bond) type display device, LED chips picked up from as small an area as possible in a wafer are collected by using the property that LED chips having similar characteristics are easily formed in a close place in the same wafer. Bonding. Also, in a display device configured by mounting LED lamps, means for measuring the brightness of each LED lamp and selecting and mounting one having a brightness within a certain range is adopted.

[0003]

However, the brightness of the LED chips varies individually to some extent, and the distribution is very wide. Therefore, when multi-coloring or multi-chip is attempted, the display device manufactured by the above-described method inevitably has a variation in brightness between the dots formed by the LEDs, and the finished display device has It was impossible to correct the variation in luminance between dots.

[0004] The existence of such a variation in luminance is a major obstacle in displaying a screen with shading by giving a gradation expression to a luminescent color.
In the case where each dot is constituted by LEDs of green and blue to perform full color display, if the brightness of each LED is not uniform, the required color will not be synthesized even if the respective emission colors are mixed, but the blue LED is The luminance is relatively low for each of the red and green LEDs. This is a factor that hinders the realization of, for example, an LED dot matrix type display device that can perform full-color display with gradation expression by inputting data for a television image.

Accordingly, an object of the present invention is to provide an LED dot matrix type display device capable of easily and accurately equalizing the brightness of each LED and displaying an image of a television receiver. It is.

[0006]

According to the present invention, as a technical means for achieving the above object, an LED dot matrix type display device is constituted as follows. That is, a dot matrix type LED display unit in which each dot is configured by combining one LED of each of red, green and blue, and a calculation in advance based on the measured luminance of each of the red, green and blue LEDs of all dots The brightness correction data for making each of the LEDs have a constant brightness is obtained by correcting the correction data memory stored at each address corresponding to the dot position and the image data input to be displayed on the LED display unit. Data conversion means for calculating and converting corrected image data based on luminance correction data sequentially read from an address of the correction data memory designated by a color select signal and a memory address signal synchronized with the image data; A video memory for storing the corrected image data calculated by the data conversion means; The LED based on the corrected image data stored in the memory
Display driving means for driving the display unit to emit light.

[0007]

Even if the red, green, and blue LEDs of the dot matrix type LED display unit have variations in luminance, the luminance is measured in advance, and luminance correction data for stabilizing the measured luminance is obtained. It is created and stored in the correction data memory in association with the dot position. Then, the image data to be displayed is determined by a color select signal and a memory address signal synchronized with the image data .
The read data is sequentially read from the specified address of the correction data memory , and the data conversion means calculates based on the read brightness correction data to change the corrected image data. Then, the corrected image data is temporarily stored in the video memory, and the display driving means drives the dot matrix type LED display unit. Thus, for example, the light emission time is controlled according to the luminance of each of the red, green, and blue LEDs, and all the LEDs are driven to emit light with the same luminance. Therefore, the image of the television receiver can be displayed in full color having a gradation expression.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a block configuration of an embodiment of the present invention in a case where image data of a television receiver is input and applied to a full-color display having a gradation expression. As a dot matrix type LED display unit (1), Red, green and blue dots
A 16 × 16 dot structure constituted by combining two LEDs is illustrated, and has a full color function. This L
The brightness of all the LEDs of the ED display unit (1) is measured in advance for each dot and each emission color, and the brightness correction data necessary to make the brightness of each dot a constant value is calculated in advance. Three P-ROs corresponding to three colors
The above-mentioned luminance correction data is stored in an address address corresponding to each dot position specified by the memory address signal in the correction data memory (2) consisting of M, which is divided for each color specified by the color select signal. ing.

When image data such as television image data is input, one line of the image data in the horizontal scanning direction is input to the multiplier (3) and synchronized with the image data. Memory for correction data specified by color select signal and memory address signal (2)
, The luminance correction data is read out from the address and input to the multiplier (3). The multiplier (3) multiplies the image data by the luminance correction data to cause each dot to emit light at a constant luminance. Is converted to The corrected image data is sequentially written by a read / write switching signal to an address of the video memory (4a) designated by the color select signal and the memory address signal,
After the writing of the corrected image data for one row is completed, the corrected image data for the next one row obtained in the same manner is written to the video memory (4b).

Next, based on the read command of the read / write switching signal, the corrected image data of three colors sequentially read from the address of the video memory (4a) designated by the color select signal and the memory address signal is green. , Red and blue display data forming circuits (5), (6) and (7) which are individually input and converted into display data for gradation display, and then converted to 16-bit green and green display data. The dot matrix type LED display unit (1) is driven to emit light via the segment drivers (8), (9), (10) for red and blue and the common driver (11), and a screen based on image data is displayed. The gradation is displayed in full color. Since each of the display data forming circuits (5), (6) and (7) has the same configuration,
Only the illustrated green display data forming circuit (5) will be described. After the corrected image data is input to the 16 four-bit latch circuits (5a) and latched to convert from a serial signal to a parallel signal, 16
B in the four 4-bit digital comparators (5b)
The image is compared with the count signal of the gray scale clock signal from the CD counter (5c), and emits light the number of times corresponding to the luminance data while counting up to 16, for example. Will be displayed. Since the emission time of each LED is controlled by the corrected image data obtained by calculating the image data based on the brightness correction data, each LED emits light with uniform luminance, and a required color is synthesized by mixing each emission color. .

[0011]

As described above, according to the LED dot matrix type display device of the present invention, the dot matrix type LE is provided.
The luminance variation of each of the red, green, and blue LEDs of the D display unit is measured in advance, and luminance correction data for stabilizing the measured luminance is created and stored in the correction data memory corresponding to the dot position. In addition, the image data to be displayed is sequentially read from the address of the memory for correction data designated by the color select signal and the memory address signal synchronized with the image data, and the data conversion unit performs based on the read luminance correction data. The modified image data is calculated by operation, and the modified image data is temporarily stored in the video memory, and the dot matrix type LED display unit is driven by the display driving means. For example, by controlling the light emission time according to the brightness that the LED has, all the LEDs emit light at the same brightness. Since it is Rukoto, an image of the television receiver, it can be displayed in full color with a gradation expression. According to the LED dot matrix type display device of the present invention, each of the red, green and blue L
Since the brightness of the ED itself can be accurately corrected, a fine and beautiful display display with uniform brightness is possible. Further, according to the LED dot matrix type display device of the present invention, the image data to be displayed is sequentially read out from the correction data memory by a color select signal synchronized with the image data, and the data conversion means is executed based on the read luminance correction data. Is calculated to change to the corrected image data, so that, for example, only one multiplier as the data conversion means can correspond to each color of red, green and blue, so that a multiplier is provided for each color A remarkable effect that the cost of the apparatus can be reduced as compared with the case can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dot matrix type LED display unit 2 Memory for correction data 3 Multiplier (data conversion means) 4a, 4b Video memory 8 Segment driver for green (display drive means) 9 Segment driver for red (display drive means) 10 Segment driver for blue (Display driving means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G09G 3/32 G09G 3/20 H04N 5/66 H04N 9/30 H04N 9/67

Claims (1)

(57) [Claims] 1. Each dot is represented by one of red, green and blue.
A dot matrix type LED display unit configured by combining a plurality of LEDs, and a unit for setting each of the LEDs, which are calculated in advance based on the measured luminance of each of the red, green and blue LEDs of all dots, to have a constant luminance. luminance correction data, a memory for correcting data stored in each address in correspondence with the dot positions, the LED input image data to be displayed on the display unit, the color select signal synchronized with the image data and
Data conversion means for calculating based on luminance correction data sequentially read from an address of the correction data memory designated by a memory address signal and converting the corrected image data into corrected image data; and the corrected image calculated by the data conversion means An LED dot matrix type display device comprising: a video memory for storing data; and display driving means for driving the LED display unit to emit light based on corrected image data stored in the video memory.