JPH1165525A - Color compensating method for large display device using led - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable visualization of images having no color slippage and a good shade by compensating the radiation intensity of a LED lamp, so as to make the radiation intensity in a prescribed range to be matched with each other an improve the color balance. SOLUTION: An analog image signal is converted into a digital signal by an AD converter 3, and a compensating coefficient signal corresponding to the address of a blue LED chip of each pixel is outputted by a compensating coefficient circuit 4. After a data signal from the AD converter 3 has been compensated in accordance with the compensating coefficient signal in a compensating circuit 5, an address signal from the AD con-verter 3 and data, in which the pulse width of a lighting pulse is compensated so as to widen the width by the compensat-ing circuit 5, are sent to a lighting controller. Consequently, a blue LED chip is turned on with a radiation intensity higher than that of other red and green LED chips. The table of compensating coefficients, which increase in the order of a LED lamp of a small address located on the lower side to lamps of large address located on the upper side, is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-sized display device using a light emitting diode (hereinafter, referred to as an LED) which is installed in a place where the visible range is relatively limited, such as a parking lot at a tourist spot or a building wall in a city center. The present invention relates to a method for correcting a color shift caused by viewing from a short distance.

[0002]

2. Description of the Related Art As a conventional structure of a full-color large-size display device, as shown in FIG.
For example, 16 × 16 LED lamps 1 in which three LED chips of green G and blue B are incorporated in one lens body L are arranged in a matrix to form one unit, and this unit is further arranged in a matrix. It was done.

Then, the LEs are arranged in a color order as shown in FIG.
When the LED lamp 1 on which the D chip is arranged is used, the green LED chip has a large radiation intensity in the horizontal direction due to the lens effect, and the blue LED chip has a predetermined (for example, 20 degrees) from the horizontal direction. The elevation of the radiation intensity is large, and the red LED chip has a large radiation intensity at a predetermined (for example, 20 degrees) depression angle from the horizontal direction, and the difference between the red and blue radiation intensities is large. When the large display device 2 is viewed from a short distance where the elevation angle shown is 3.6 to 19.9 °, the color shift increases as the elevation angle increases.

[0004]

To solve this problem, it is conceivable to install a large display device 2 as shown in FIG. 6 downward, as shown in FIG. In addition to the structural problems described above, aesthetic problems also arise.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has as its object to correct the radiant intensity in a specific range of an LED lamp incorporating a plurality of LED chips having different emission colors, and to improve the near-intensity. It is an object of the present invention to provide a color correction method for a large-sized display device using an LED that does not have a color shift even when the display device is viewed from a distance.

[0006]

SUMMARY OF THE INVENTION A color correcting method for a large-sized display device using LEDs according to the present invention achieves the above-mentioned object, and the method comprises a plurality of LEs having different emission colors.
In a large display device in which LED lamps containing D chips are arranged in a matrix and installed at a place where the LED lamp is viewed from a specific range, the emission of the LED lamp is improved in order to match the radiation intensity in a specific range and improve color balance. The intensity was corrected.

[0007] Further, there is provided a correcting means for correcting the radiation intensity of the LED chip disposed at a position where the optical axis, which is the center of the light distribution, is directed upward or to the left or right of the large display device. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A circuit for implementing a color correction method for a large display device using LEDs according to the present invention will be described below with reference to FIG. In order to facilitate understanding of the embodiment, a method for correcting the radiation intensity of one LED chip will be described. Reference numeral 3 denotes an AD converter for converting an analog image signal into a digital signal, and reference numeral 4 denotes an LED chip (a blue LED chip in this embodiment) to be turned on by an address signal in each pixel from the AD converter 3. A correction coefficient circuit 5 for determining a correction coefficient for correcting time (pulse width) is a correction circuit for correcting a data signal from the AD converter 3 to a lighting time based on a correction coefficient from the correction coefficient circuit 4. is there.

With the circuit thus configured, the analog image signal is converted into a digital signal by the AD converter 3, and the correction coefficient circuit 4 outputs a correction coefficient signal corresponding to the address of the blue LED chip of each pixel. In the correction circuit 5, A is set according to the correction coefficient signal.
After correcting the data signal from the D converter 3, AD
The address signal from the converter 3 and the data in which the pulse width of the lighting pulse is corrected to be long by the correction circuit are sent to the lighting control device.

As a result, the blue LED chip is illuminated with a higher radiation intensity than the other red and green LED chips, that is, as shown in FIG. Even if an image is viewed from a position close to the display device 2, the image can be viewed without feeling color shift.

Note that if the emission intensities of all the blue LED chips are uniformly increased by one correction coefficient, for example, by 20%, the emission intensities of all the blue LED chips become B
Therefore, when the emission intensity of the lower blue LED chip in the large display device 2 is adjusted to a state in which the color balance is good, the emission intensity of the upper blue LED chip becomes lower. And the color balance deteriorates.

Therefore, as shown in the correction table shown in FIG. 3, by using a table of the correction coefficient which increases in the order from the lower address LED lamp located at the lower side to the higher address located at the upper side, the large display device 2 The overall color balance can be improved, and the color shift can be corrected.

Further, in the above-described embodiment, the method of correcting the pulse width in the pulse width modulation to be long has been exemplified. However, it is also possible to use the method of correcting the current or the voltage to adjust the radiation intensity. is there.

Further, in the above-described embodiment, the case where the radiation intensity of only the blue LED chip is corrected has been described. However, the green and red LED chips can be corrected by using the correction coefficient table. As shown in FIG. 4, it is possible to manufacture a large-sized display device with good color balance in which the radiation intensities of the three colors in a specific visual range are further matched.

Further, in the above-described embodiment,
By arranging the LED chips in the LED lamp 1 in the order of red, green, and blue from the top, the brightness of blue in the downward direction from horizontal is reduced, so that the brightness of the blue was controlled to be high. If the brightness of other colors is reduced by changing the arrangement, control may be performed so as to increase the radiation intensity of the LED chip.

Further, in the above-described embodiment, 3
Although the case of the large-sized display device 2 with the color LED chips has been described, the colors of the LED chips are not limited to three colors, and the LED chips of two or more colors may be vertically or horizontally, and the position using both of them. In this case, color misregistration occurs in the vertical or horizontal direction, so that the above-described method of the present invention can of course prevent color misregistration.

[0017]

According to the present invention, as described above, in an LED lamp incorporating a plurality of LED chips having different emission colors, the brightness of an LED chip having a low brightness in a specific direction is increased so that the brightness or the brightness ratio becomes the same. As a result, even if the large-sized display device is viewed from either the short distance or the left or right direction, there is no color shift and an image having a good color tone can be viewed.

[Brief description of the drawings]

FIG. 1 is a block diagram for implementing the method of the present invention.

FIG. 2 is a diagram showing a state where the radiation intensity of a blue LED chip is corrected by the method according to the present invention.

FIG. 3 is a diagram of a table showing correction coefficients.

FIG. 4 is a diagram showing the luminance of each LED in a state where three color LEDs are turned on.

FIG. 5 is a diagram showing radiation intensity in a specific visual recognition range.

FIG. 6 is a side view of a state where the large display device is viewed from a specific range.

[Explanation of symbols]

 R, G, B Red, green, blue LED chips 1 LED lamp 2 Large display device 3 AD converter 4 Correction coefficient circuit 5 Correction circuit

Claims (2)

[Claims] An LED lamp containing a plurality of LED chips having different emission colors is arranged in a matrix, and in a large-sized display device installed at a place viewed from a specific range, a color is adjusted by matching radiation intensity in a specific range. A color correction method for a large-sized display device using LEDs, wherein a radiation intensity of the LED lamp is corrected to improve balance. 2. A correction device for correcting the radiation intensity of the LED chip disposed at a position where an optical axis, which is a center of light distribution, is directed upward or leftward or rightward of the large display device. A color correction method for a large display device using the LED according to claim 1.