Display device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a display device capable of displaying white, and more specifically, each display body having at least three color systems of red, green and blue uses each color display as a display unit (dot or pixel) and is white. It relates to a display device capable of automatically adjusting the balance and the reproduced color balance.

【0002】

[Conventional technology]

In recent years, as a display device in the field of information display indoors or outdoors, a so-called full-color LED display system that uses light emitting diodes (hereinafter referred to as LEDs) for each display body consisting of three colors of red, green, and blue. Is rapidly becoming widespread, and it is expected that demand for high-definition television (HDTV) standard high-definition video display will increase in the near future.

【0003】

In such a full-color LED display system, conventional display data signals in the NTSC format image signal (R, G and B signal) format from each video device such as a television, a VCR, a laser disc player, and a video camera are imaged. Often used as a source.

【0004】

However, according to the video source, there is a difference in color reproduction due to the difference in the output value of the display data signal of the NTSC system image signal (R, G and B signal) format from each of the video devices, and in particular, it is general. In an outdoor display device in which the video source is frequently switched between video devices, it is an indispensable problem to solve the problem of such a difference in color reproduction.

【0005】

In addition, in this type of outdoor display device, the external light conditions such as the illuminance around the display device differ depending on the installation location, and the relative luminous efficiency characteristics of the observer (person) shift depending on the time zone, weather, etc., and are reproduced. There is a problem that the color balance, especially the white balance, cannot be kept constant, and this problem is highlighted as high image quality is required.

【0006】

In the conventional full-color-LED display system, the three basic colors of colored light, red, green, and blue, are fixed to the predetermined set values, and the reproduced color balance, especially the white balance, can be corrected at any time. It was difficult.

【0007】

Furthermore, the red LEDs, green LEDs, and blue LEDs used in ordinary full-color LED display systems have different deterioration characteristics, and are reproduced as the display time elapses, that is, as the integrated display time increases. There is a problem that the color balance gradually collapses from the initial predetermined state and the display color quality deteriorates. To correct this, it is necessary to periodically readjust the brightness of all the units.

【0008】

[Problems to be Solved by the Invention]

An object of the present invention is that in a full-color display system, the three basic primary colors of red, green, and blue gradually change from a predetermined set value, or the reproduced color balance is caused by a difference in a video source or a change in ambient illuminance. In particular, the purpose is to realize a display device that can cope with changes in white balance and loss of color reproduction.

【0009】

Further, an object of the present invention is to gradually lose the white balance because the brightness aging (deterioration) characteristics of the red LED, the green LED, and the blue LED constituting the three colors are different, particularly in the full-color LED display system. The purpose is to realize a display device that can handle the above.

【0010】

Furthermore, an object of the present invention is to provide a control means for automatically adjusting a useful white balance or color balance at an arbitrary time by equipping a full-color display system.

【0011】

[Means for solving problems]

In order to solve this problem, the display device of the present invention includes a display unit capable of white display in which display bodies having at least three color systems of red, green, and blue are arranged close to each other, and the display unit of the display unit. It is equipped with a control unit that can automatically adjust the white balance, which allows the chromaticity of the display unit at any time, in this case the chromaticity defined on the CIE (International Commission on Illumination) chromaticity diagram. (Hereinafter, simply referred to as chromaticity), or the illuminance around the display unit can be detected, and the control unit can correct the deviation from the set chromaticity value to return it to the specified set value to keep the white balance constant at any time. It is something that can be done.

【0012】

BEST MODE FOR CARRYING OUT THE INVENTION

The invention according to claim 1 automatically adjusts the white balance of a display unit capable of displaying white and the display unit having at least three color systems of red, green, and blue arranged close to each other. It is equipped with a control unit that can be used, and the control unit corrects the deviation from the set chromaticity value to return it to the predetermined set value, and has the effect of maintaining a constant white balance during darkening. Have.

【0013】

The invention according to claim 2 detects at least one of the chromaticity of a predetermined white display and the illuminance around the display unit, and each display is composed of at least three color systems of red, green, and blue according to the detected values. It is equipped with a means to automatically adjust the white balance by controlling the output of any color system of the body, and the control unit corrects the deviation from the set chromaticity value to return it to the predetermined set value, and white at the time of stagnation. It has the effect of keeping the balance constant.

【0014】

The invention according to claim 3 is an independent gamma correction value of each of the display bodies as a means for controlling the output of an arbitrary color system of each display body having at least three color systems of red, green, and blue. It has a means for adjusting by changing, and has an effect that the deviation from the set chromaticity value can be immediately corrected by the control unit to return to a predetermined set value, and the white balance can be kept constant.

【0015】

The invention according to claim 4 is a color reproduction range according to the output from each display body as a means for controlling the output of an arbitrary color system of each display body having at least three color systems of red, green and blue. Is divided into two or more areas, and the color conversion ability set in each area is changed to have a means for adjusting to an arbitrary display color. A white light emitting monitor is used in addition to the display device main body. By providing a control means for detecting the white tint at an arbitrary time and automatically adjusting the white balance at an arbitrary time, the white balance of the display unit can be kept constant at any time.

【0016】

The invention according to claim 5 has a personal computer possessed by a predetermined software as a means for automatically adjusting the white balance, whereby the white balance of the display unit can be kept constant at any time. Has an action.

【0017】

The invention according to claim 6 detects the chromaticity of a predetermined white display by a white display monitor unit in which display bodies having at least three color systems of red, green, and blue are arranged close to each other. It is characterized by automatically adjusting the white balance, and has an effect that the white balance of the display unit can be kept constant at any time.

【0018】

The invention according to claim 7 uses a light emitting diode for each display body, and has an effect that the white balance of the display unit can be kept constant at any time.

【0019】

According to the eighth aspect of the present invention, the drive signal supplied to each display body of the display unit is formed by a display data signal in the form of an NTSC image signal (R, G and B signal). In addition, it has the effect of keeping the white balance of the display unit constant at any time.

【0020】

The invention according to claim 9 includes a display unit capable of emitting white light, a monitor display unit that constantly lights white as a part of the display unit, a chromaticity meter capable of externally outputting a chromaticity value, and the color. For signal conversion between a personal computer owned by a predetermined software capable of inputting meter data and outputting display data in NTSC image signal (R, G and B signals) format, and the display unit and the computer. It is provided with an interface circuit, which has an effect of keeping the white balance of the display unit constant at any time.

【0021】

The invention according to claim 10 is an NTSC type image signal by inputting a display unit capable of emitting white light, an illuminometer that measures and outputs data of the illuminance around the display unit, and data of the illuminometer. A computer possessed by a predetermined software capable of outputting a display data signal in the (R, G and B signal) format and changing the color conversion ability, and a signal conversion interface circuit between the display unit and the computer. This has the effect of keeping the white balance of the display unit constant at any time.

【0022】

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

【0023】

1, FIG. 2, FIG. 3 and FIG. 4 are block configuration diagrams of the respective display devices according to the first to fourth embodiments of the present invention. In each of these figures, each component of each display device is commonly coded, and the display unit 1, the monitor unit 2, the chromaticity meter 3, the luminometer 4, the measured value processing unit 5, and the control circuit unit ( Computer) 6, video source unit 7, signal conversion unit 8, display interface unit 9, communication interface unit 9a, gamma correction circuit 9b, storage circuit (RAM) 9c, color conversion processing circuit 9d, panel interface 9e, external data processing unit It is shown as 10 and the signal (data) processing path is represented by lines and arrows.

【0024】

(Embodiment 1) The display device of the first embodiment of the present invention will be described with reference to the block configuration diagram of FIG.

【0025】

The display unit 1 includes a display body that displays white in three colors of red, green, and blue, for example, a red LED, a green LED, and a blue LED.

【0026】

The monitor unit 2 is a monitor display unit that is a display body that displays the white color of one unit of the display unit 1. The monitor unit 2 is always lit in white when the display unit 1 is lit, and the lighting rate is set so as to match the average power when lit for one unit of the display unit 1. As a result, the luminance characteristic with time, that is, the luminance deterioration can be made equivalent to each display body of the display unit 1.

【0027】

The chromaticity meter 3 measures the chromaticity (x, y) of the monitor unit 2 during white display, and can output the chromaticity value to the outside at an arbitrary time by an external signal. It also has a timer that can turn the power on and off at any time.

【0028】

The measured value processing unit 5 is a converter that converts the output signal of the chromaticity meter 3 and converts it into a signal that matches the interface of the control circuit unit (computer) 6. Further, the control circuit unit 6 inputs a video source signal from the video source unit 7 made of a video disk, an optical disk, or the like, and internally matches the display drive of the display unit 1 with an NTSC system image signal (R, G, B signal). , Hereinafter referred to as an analog RGB signal), etc., and has an interface that can be converted and output.

【0029】

The signal conversion unit 8 includes a converter (A / D converter, etc.) that converts the output signal (analog RGB signal) from the control circuit unit 6 into a digital signal (hereinafter referred to as a digital RGB signal) suitable for the interface. ..

【0030】

The display interface unit 9 is provided with a device that converts an output signal (digital RGB signal) from the signal conversion unit 8 into a signal in a signal format suitable for the display drive of the display unit 1.

【0031】

While the display unit 1 is displaying, the monitor unit 2 is always lit so as to be white at a predetermined lighting rate. For example, when the display unit 1 is displaying an image, the lighting rate is set to 40%.

【0032】

The chromaticity meter 3 sequentially measures the chromaticity value according to the scheduled time. The chromaticity value at this time is input to the measured value processing unit 5, converted into a data format suitable for the interface of the control circuit unit 6, and transmitted to the control circuit unit 6. In the control circuit unit 6, the processing software in which the optimum color conversion ability (table) is stored corresponds to the chromaticity value, and is transmitted to the communication interface unit 9a of the display interface unit 9.

【0033】

The chromaticity value data signal input to the communication interface unit 9a is stored in the RAM 9c in the display interface unit 9, and this data is referred to during the color conversion process.

【0034】

The analog RGB signal or the like output from the control circuit unit 6 is input to the gamma correction circuit 9b in the display interface unit 9. After that, the color conversion processing circuit 9d performs the optimum color conversion at the present time, and after the color conversion, it is converted into a signal for panel display through the panel interface 9e, and the data is output to the panel for display. ..

【0035】

(Embodiment 2) The display device of the second embodiment of the present invention will be described with reference to the block configuration diagram of FIG.

【0036】

The illuminometer 4 can measure the illuminance around the display unit 1 and output the illuminance value to the outside at an arbitrary time by an external signal. It also has a timer that can turn the power on and off at any time.

【0037】

While the display unit 1 is driven to the display state, the illuminance meter 4 installed in front of the panel display unit 1 measures the illuminance according to the scheduled time.

【0038】

The illuminance value at this time is input to the measured value processing unit 5, converted into a data format suitable for the interface of the control circuit unit 6, and transmitted to the control circuit unit 6.

【0039】

The optimum gamma correction capability (table) for the illuminance value corresponds to the predetermined processing software built in the control circuit unit 6, and is transmitted to the communication interface unit 9a of the display interface unit 9.

【0040】

The gamma correction capability (table) input to the communication interface unit 9a is stored in the RAM 9c in the display interface unit 9, and this data is referred to during the gamma correction processing.

【0041】

The analog RGB signal or the like output from the control circuit unit 6 is input to the gamma correction circuit 9b in the display interface unit 9. At this time, the gamma correction capability stored in the RAM 9c is referred to, and the optimum weighting process is performed for the analog RGB signal or the like. After that, color conversion is performed by the color conversion processing circuit 9d, and after this color conversion, it is converted into a signal for driving the panel display through the panel interface 9e, and the data is output to the display unit 1 for display. Will be done.

【0042】

(Embodiment 3) The display device of the third embodiment of the present invention will be described with reference to the block configuration diagram of FIG.

【0043】

While the display unit 1 is driven to the display state, the monitor unit 2 is always set to a predetermined lighting rate, for example, when the display unit 1 is displaying an image, the lighting rate is set to 40% and becomes white. It is lit like this.

【0044】

The chromaticity meter 3 sequentially measures the chromaticity value at each time according to the scheduled time. The chromaticity value at this time is input to the external data processing unit 10 in the display interface unit 9, and transmitted to the control circuit unit 6 through the communication interface unit 9a.

【0045】

The optimum color conversion capability (table) for the chromaticity value is processed by the processing software in the control circuit unit 6 and transmitted to the communication interface unit 9a in the display interface unit 9.

【0046】

The color conversion capability (table) input to the communication interface unit 9a is stored in the RAM 9c in the display interface unit 9, and this data is referred to during the color conversion process.

【0047】

The analog RGB signal or the like output from the control circuit unit 6 is input to the gamma correction circuit 9b in the display interface unit 9, and then the color conversion processing circuit 9d performs the optimum color conversion at the present time, and further, the color is performed. After the conversion, it is converted into a signal for driving the panel display through the panel interface 9e, and the data is output to the display unit 1 for display.

【0048】

(Embodiment 4) The display device of the fourth embodiment of the present invention will be described with reference to the block configuration diagram of FIG.

【0049】

While the display unit 1 is driven to the display state, the illuminance meter 4 installed on the front side of the display unit 1 measures the illuminance value according to the scheduled time.

【0050】

The illuminance value at this time is input to the external data processing unit 10 in the display interface unit 9, and the data value is transmitted to the control circuit unit 6 through the communication interface unit 9a.

【0051】

The optimum gamma correction capability (table) for the illuminance value is transmitted to the communication interface unit 9a in the display interface unit 9 by the processing software in the control circuit unit 6.

【0052】

The gamma correction capability (table) received by the communication interface unit 9a is stored in the RAM 9c in the display interface unit 9, and this data is referred to during the gamma correction processing.

【0053】

The analog RGB signal or the like output from the control circuit unit 6 is input to the gamma correction circuit 9b of the display interface unit 9. At this time, the gamma correction value of the gamma correction capability (table) stored in RAM9c is referred to, optimal weighting is performed for each RGB output, and then color conversion is performed by the color conversion processing circuit 9d, and further, After the color conversion, it is converted into a signal for driving the panel display through the panel interface 9e, and the data is output to the display unit 1 for display.

【0054】

Next, the outline of the color conversion algorithm will be described.

【0055】

First, a color conversion algorithm based on the gamma correction method will be described.

【0056】

As shown in Fig. 5 (a), the ideal white chromaticity most suitable for panel display 1 is output of each of the red, green, and blue displays, R = a · | R | Set the chromaticity (x, y) as / max, G = b · | G | / max, B = c · | B | / max.

【0057】

Here, R, G, and B are red, green, and blue vectors based on the chromaticity (x, y) of white, respectively, and | R |, | G |, | B | are, respectively. , Red, green, and blue are the absolute values of each vector, and a, b, c, max are arbitrary positive integers. In other words, the chromaticity (x, y) is based on the concept that it can be expressed by three vectors R, G, B.

【0058】

Next, it is assumed that the white balance of the display unit 1 changes at an arbitrary time T, and the measured value at that time is the chromaticity (x', y'). Similarly, as shown in Fig. 5 (b), when the chromaticity (x', y') at time T is expressed by three vectors R', G', B', the chromaticity (x, y) is expressed. Unlike the case, the absolute value of the vector is R'= dR, G'= eG, B'= fB. Where d, e, f are any positive real numbers. Therefore, the output value at this time is (1 / d) R'= a | R | / max, (1 / e) G'= b | G | / max, (1 / f) B'= c If the calculation is performed so that | B | / max, as shown in Fig. 5 (c), the vectors R , G, B will be the same as the set values R, G, B, and the colors will be the same. The degree (x', y') can be returned to the set value chromaticity (x, y).

【0059】

[table 1]

<img file="JP2000293133A_D0001.tif" />【0060】

Table 1 uses four types of LEDs: red emission (R-LED), pure green emission (PG-LED), blue emission (B-LED), and yellow-green emission (YG-LED). , When each LED is at its typical brightness, it displays the chromaticity coordinates (x, y) pointed out on the CIE chromaticity diagram.

【0061】

[Table 2]

<img file="JP2000293133A_D0002.tif" />【0062】

In addition, Table 2 shows the brightness ratio when the above four types of LEDs are used to initialize the seven basic colors of red, green, blue, yellow, cyan, magenta, and white (the numerical values here are the panel itself. It is different from the gradation that it has, and has 256 gradations (0 to 255) as weights. Since the weights are standardized at 255, the actual brightness of the panel is (gradation / brightness ratio) / It is 255.), The chromaticity coordinates (x, y) and the typical brightness are displayed.

【0063】

FIG. 6 shows the state of the shift of each chromaticity coordinate when the red output value and the blue output value are reduced by 10% and 20%, respectively, from the initial setting values of chromaticity and brightness in Table 2.

【0064】

In the figure, mark is the basic initial setting value, mark is the chromaticity coordinate when the red output value is reduced by 10%, mark is the chromaticity coordinate when the red output value is reduced by 20%, mark. Indicates the chromaticity coordinate when the blue output value is reduced by 10%, and the circle indicates the chromaticity coordinate when the blue output value is reduced by 20%.

【0065】

Focusing on the shift of white (white, indicated by point W), white is the direction of point W seen from blue (blue, indicated by point B) and the point viewed from red (red, indicated by point R). It can be seen that there is a slight shift in the direction of W. Similarly, it is possible to shift in the direction of point W as seen from green (green, indicated by point G). That is, by adjusting each output value of the red system, the green system, and the blue system, the white balance can be maintained at the set value according to the external situation.

【0066】

In addition, by giving a margin to the brightness ratio in advance and using it in a state where the brightness is lowered as a whole with respect to the maximum performance (a value lower than the maximum value of 255, for example, a value of 220 is used). It is also possible to shift from point W to points R, G, and B.

【0067】

Also, paying attention to the shift of magenta (displayed at point M), by changing the blue output value and the red output value, the line segment created by points B and R can be set arbitrarily. be able to. Similarly, by adding a greenish output value to the adjustment, the hue of the mixed color can be freely set.

【0068】

Next, the color conversion algorithm by the color conversion ability (table) method will be described.

【0069】

It has been conventionally known to perform color correction by linear calculation in order to enhance image reproduction of a full-color LED display system (see, for example, Japanese Patent Application Laid-Open No. 9-98443).

【0070】

By changing the color conversion ability according to the external chromaticity value or the illuminance value, the display chromaticity of the seven basic colors of red, green, blue, yellow, cyan, magenta, and white can be freely set.

【0071】

[Table 3]

<img file="JP2000293133A_D0003.tif" />【0072】

Table 3 shows the values when the color conversion capability (table) is changed. Moreover, these values are shown on the chromaticity diagram of FIG.

【0073】

By changing the brightness combination ratio of each LED, it is possible to fine-tune the chromaticity value, and correct and set the chromaticity deviation due to the difference in the video source and the chromaticity deviation due to the time zone near the display unit 1 and the weather. The value can be kept.

【0074】

In addition, by giving a margin to the brightness of each LED (such as emitting light at a brightness of 80% for a maximum brightness of 100%), the LED shifts from point W to points R, G, and B. It is also possible to make it.

【0075】

Furthermore, by changing the setting points of the seven basic colors, it is possible to freely set the hue shift and the like.

【0076】

The illuminance in the vertical direction is measured with respect to the front side of the display unit 1, and the relationship between the chromaticity at that time and the illuminance basic setting table is shown in Table 4. These values are shown on the chromaticity diagram of FIG.

【0077】

[Table 4]

<img file="JP2000293133A_D0004.tif" />【0078】

By preparing several types of tables and several types of gamma correction values in advance with the illuminance value as a reference parameter, the white balance and color balance of the display unit 1 can be corrected at any time, and the set values can be kept constant at all times. Can be done. In addition, there are differences in video sources (differences in output characteristics of devices such as TVs, VCRs, laser disc players, camcorders, and DVDs), and the brightness aging (deterioration) characteristics of red LEDs, green LEDs, and blue LEDs. With regard to differences, etc., automatic adjustment can be supported by setting each characteristic in advance.

【0079】

The embodiments or examples of the present invention shown above are examples for embodying the technical idea of the present invention, and the present invention is not specified in these examples, and all indications indoors and outdoors. Applicable to devices.

【0080】

[Effect of the invention]

As described above, the display device of the present invention has a display unit capable of white display in which display bodies having at least three color systems of red, green, and blue are arranged close to each other, and a white balance of the display unit. By providing a control unit capable of automatically adjusting the white balance of the display unit, the white balance of the display unit can be kept constant at any time.

【0081】

Further, according to the present invention, the chromaticity or illuminance of the display unit is measured at an arbitrary time, a deviation from the set chromaticity value is detected, and a calculation for returning to the set value is performed to keep the white balance constant. Therefore, it is possible to realize a display device having high image quality without any deviation in color reproducibility due to a difference in image source, a change in ambient illuminance, or a difference in brightness deterioration of red, green, and blue light emitting elements.

[Simple explanation of drawings]

[Figure 1]

Block configuration diagram of the display device according to the first embodiment of the present invention [Figure 2]

Block configuration diagram of the display device according to the second embodiment of the present invention [Fig. 3]

Block configuration diagram of the display device according to the third embodiment of the present invention [Fig. 4]

Block configuration diagram of the display device according to the fourth embodiment of the present invention [Fig. 5]

Conceptual diagram of white balance calculation algorithm using gamma correction [Fig. 6]

CIE chromaticity diagram explaining chromaticity shift by gamma correction method [Fig. 7]

CIE chromaticity diagram explaining chromaticity shift by color conversion ability (table) method [Fig. 8]

CIE chromaticity diagram explaining chromaticity shift with respect to external illuminance value [Explanation of symbols]

1 Display 2 Monitor unit 3 Chromatic meter 4 Illuminance meter 5 Measured value processing unit 6 Control circuit section (computer) 7 Video source section 8 Signal converter 9 Display interface 9a Communication interface section 9b gamma correction circuit 9c RAM 9d color conversion processing circuit 9e panel interface 10 External data processing unit