JPH0744132A - Led display device - Google Patents

Abstract

PURPOSE:To suppress the breakage of an LED element and the shortening of element life by suppressing an excessive rise in the temperature of an LED display screen. CONSTITUTION:When a data conversion part 1 converts a video signal to be displayed on the display screen into a signal for LED display, a luminance measuring part 2 measures the mean luminance of the entire display screen with the converted data and a threshold value setting part 3 sets the threshold value, used by the data conversion part, again in the direction wherein the mean luminance is suppressed on the basis of the mean luminance measured by the luminance measuring part. The threshold value when the video signal to be displayed on the display screen 4 is converted into the signal for LED display is dynamically adjusted based on the threshold value given by the threshold value setting part 3. Then, if the mean luminance of the display screen rises, the threshold value of the data conversion part is dynamically adjusted in the direction wherein the mean luminance is suppressed to suppress the temperature rise of an LED element, thereby suppressing the breakage of the element and the shortening of the element life.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED display device in which a display screen is formed by arranging a large number of LED elements in dot units or module units.

[0002]

2. Description of the Related Art LE in dot units or module units
A display screen is configured by arranging a large number of D elements, and L for displaying character data, graphic data, video data, etc.
Since the brightness is generally adjusted by adjusting the width of the lighting signal pulse of the LED element in the ED display device, when the image data is to be displayed on the display screen, the image such as the NTSC signal is displayed. It is necessary to convert the signal to a signal for an LED display device.

In the conventional LED display device, as a threshold value used when converting such a video signal,
A certain threshold was set regardless of the displayed video content.

[0004]

However, in such a conventional LED display device, a video signal is converted using a constant threshold value regardless of the video content to be displayed. There was such a problem. Generally, in the case of a video signal, the lighting rate of the LED element is higher than that of the text data, and it is also difficult to measure the lighting rate before displaying it like graphic data and process it to suppress the lighting rate. Therefore, when an image is displayed so that bright scenes are continuous, L
The temperature of the ED element rises, and eventually the LED element is damaged,
There is a problem that the life of the element is shortened.

The present invention has been made in view of the above-mentioned conventional problems, and the average luminance of the entire display screen is measured,
Provided is an LED display device which has a dynamic threshold value adjusting function of changing a threshold value in a direction of suppressing the brightness when the average brightness becomes high, and which can suppress damage of an LED element and a decrease in element life. The purpose is to

The present invention also has a dynamic threshold value adjusting function for measuring the average surface temperature of the entire display screen and changing the threshold value so as to suppress the temperature rise when the average surface temperature becomes high, An object of the present invention is to provide an LED display device capable of suppressing damage to the LED element and shortening of the life of the element.

Further, the present invention measures the average luminance and the average surface temperature of the entire display screen, and when the average luminance or the average surface temperature becomes high, the dynamic threshold value is changed so as to suppress the luminance or temperature rise. It is an object of the present invention to provide an LED display device that has various threshold adjustment functions and can prevent damage to the LED element and a reduction in the element life.

[0008]

According to a first aspect of the present invention, in an LED display device in which a large number of LED elements in dot units or module units are arranged to form a display screen, a video signal to be displayed on the display screen is LED. When converting for display, a data conversion unit that dynamically adjusts the threshold value, a brightness measurement unit that measures the average brightness of the entire display screen from the data converted by the data conversion unit, and a brightness measurement unit. The threshold value setting unit variably sets the threshold value used in the data conversion unit according to the level of the average brightness.

According to a second aspect of the present invention, when converting a video signal to be displayed on the display screen for LED display in an LED display device in which a large number of LED elements in dot units or module units are arranged to form a display screen. In addition, the data conversion unit that dynamically adjusts the threshold value, the temperature measurement unit that measures the average surface temperature of the entire display screen, and the average surface temperature measured by the temperature measurement unit. And a threshold value setting unit for variably setting a threshold value.

According to a third aspect of the invention, in an LED display device in which a large number of LED elements in dot units or module units are arranged to form a display screen, when converting a video signal to be displayed on the display screen for LED display. In addition, a data conversion unit that dynamically adjusts the threshold value, a brightness measurement unit that measures the average brightness of the entire display screen from the data converted by the data conversion unit, and a temperature measurement that measures the average surface temperature of the entire display screen. Section and the average brightness level measured by the brightness measurement section and the average surface temperature level measured by the temperature measurement section, the threshold value used in the data conversion section is variably set by making a composite judgment. And a threshold value setting section.

According to a fourth aspect of the present invention, in the LED display device according to any one of the first to third aspects, the processing control section further performs the threshold update setting of the threshold setting section when a predetermined condition is satisfied. It is equipped with.

[0012]

In the LED display device according to the present invention, the video signal to be displayed on the display screen by the data conversion unit is LED-displayed.
When converting for display, the brightness measurement unit measures the average brightness of the entire display screen from the converted data, and the threshold setting unit sets the data based on the level of the average brightness measured by the brightness measurement unit. The threshold used in the converter is variably set. Then, in the data conversion section, based on the threshold value given by the threshold value setting section, the video signal to be displayed on the display screen is led.
Dynamically adjust the threshold when converting for display.

In this way, when the average brightness of the display screen rises, the threshold value of the data conversion section is dynamically adjusted to suppress the average brightness so as to suppress the increase of the average brightness of the display screen, and thus the LED element. The temperature rise of the device is suppressed, and the damage of the device and the shortening of the device life are suppressed.

In the LED display device according to the second aspect of the present invention, the video signal to be displayed on the display screen by the data conversion unit is L.
When converting for ED display, the temperature measuring unit measures the average surface temperature of the entire display screen, and the threshold setting unit determines whether the average surface temperature measured by the temperature measuring unit is high or low. The threshold used is variably set. Then, the data conversion unit dynamically adjusts the threshold value for converting the video signal to be displayed on the display screen for LED display based on the threshold value given by the threshold value setting unit.

In this way, when the average surface temperature of the display screen rises, the threshold value of the data converter is dynamically adjusted so as to suppress the increase of the average surface temperature.
The temperature rise of the D element is suppressed, and the damage of the element and the reduction of the life of the element are suppressed.

In the LED display device according to the third aspect of the invention, the video signal to be displayed on the display screen by the data conversion unit is L.
When converting for ED display, the brightness measurement unit measures the average brightness of the entire display screen based on the data converted by the data conversion unit, and the temperature measurement unit measures the average surface temperature of the entire display screen. , The threshold value setting section makes a composite judgment based on the high and low of the average brightness measured by the brightness measuring section and the high and low of the average surface temperature measured by the temperature measuring section, and the threshold value used in the data converting section. Variably set. Then, in the data conversion unit, based on the threshold value given by the threshold value setting unit,
Dynamically adjust the threshold value when converting the video signal to be displayed on the display screen for LED display.

Thus, the average brightness of the display screen rises,
As a result, when the average surface temperature rises, the threshold value of the data conversion unit is dynamically adjusted to suppress the increase of the average surface temperature, the temperature rise of the LED element is suppressed, the damage of the element and the life of the element are reduced. Suppress the decline.

According to a fourth aspect of the present invention, in the LED display device according to any of the first to third aspects, there is further provided a processing control section for performing the threshold update setting of the threshold setting section when a predetermined condition is satisfied. As a result, the threshold value of the data conversion unit is changed at regular time intervals or only when the brightness or temperature rises significantly beyond a predetermined value, and the brightness of the display screen is changed frequently. Avoid making as many changes as possible to avoid compromising the readability of the display screen.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a block diagram of an embodiment of the LED display device according to the invention of claim 1, a data conversion unit 1 for converting a video signal sent as a display material into a display signal for the LED display device, an LED display screen. A brightness measuring unit 2 for measuring the average brightness of the whole, a threshold value setting unit 3 for setting a threshold value used in the data converting unit 1, and a large number of LED elements in dot units or module units are arranged to form a display screen. The LED display device 4 is operated.

The data conversion unit 1 performs operations such as Y / C separation and threshold processing on the video signal obtained as the NTSC signal, and the LED like the analog RGB signal.
The brightness measurement unit 2 calculates the average brightness and brightness histogram of the entire screen from the data converted by the data conversion unit 1, and the threshold setting unit 3 measures the brightness measurement unit 2 by the brightness measurement unit 2. The threshold value is re-set so that the average brightness thus obtained is used as the set value, and is given to the data conversion unit 1.

Next, the operation of the LED display device having the above structure will be described. Here, as an example, the set brightness is 5
The threshold value setting process when 0% lighting is described. The brightness measuring unit 2 measures a brightness histogram divided into 256 stages from the data converted by the data converting unit 1, and calculates a brightness average value from the obtained brightness histogram data. Now, the luminance histogram data measured by the luminance measuring unit 2 is as shown in FIG.
It is assumed that the average luminance value is also as shown in FIG.

Then, the threshold setting unit 3 judges whether the average brightness value obtained by the brightness measuring unit 2 is larger than the set brightness, and if it is larger than the set brightness, the threshold value is reset. Make settings. That is, as shown in FIG. 3, the origin of the threshold straight line A is fixed, a new threshold straight line B is drawn so that the brightness at the position of the average brightness value becomes the set brightness, and the brightness at the position of the average brightness value is the LED. The lighting rate of each luminance step is reset so that the lighting rate becomes 50%.

When this is expressed by an equation,

[Equation 1] Becomes

Therefore, the data conversion unit 1 suppresses the average brightness of the entire display screen to the set brightness by performing data conversion using the threshold value calculated by the threshold value setting unit 3.
Even if a video signal of a relatively bright video is input to the data conversion unit 1, it is possible to automatically suppress the brightness and display it on the LED display screen, suppressing the temperature rise of the LED element and overheating. It becomes possible to suppress the damage of the element and the shortening of the life of the element due to.

The invention of claim 1 is not limited to the above embodiment, and the process of changing the threshold value based on the brightness measurement value does not depend on the equation (1). ] / [Average brightness] based on the value of the whole brightness may be simply processed, or another method may be used.

Next, an embodiment of the invention of claim 2 will be described in detail with reference to FIG. The LED display device according to the invention of claim 2 converts a video signal to be displayed on the display screen for LED display, and has a function of dynamically adjusting a threshold value, a data conversion unit 1, an average surface of the entire display screen. The temperature measuring unit 5 for measuring the temperature and the threshold setting unit 3 for resetting the threshold value used in the data converting unit 1 based on the height of the average surface temperature measured by the temperature measuring unit 5 are provided.

In this embodiment as well, the data converter 1 converts the video signal into an LED display signal and outputs it as in the embodiment shown in FIG. Then, the temperature measuring unit 5 measures the average temperature of the entire display screen based on the signals from the temperature sensors arranged at a plurality of appropriate places on the display screen of the LED display device 4, and the threshold setting unit 3 determines the average temperature. When the average temperature measured by the measurement unit 5 is higher than a predetermined reference value, the threshold value is reset and given to the data conversion unit 1 in the direction in which the average temperature of the display screen decreases. .

The operation of the LED display device having the above structure will be described. The temperature measuring unit 5 takes in temperature signals from temperature sensors arranged at appropriate places of the LED display device 4, calculates an average temperature of the entire display screen, and gives it to the threshold value setting unit 3.

The threshold value setting section 3 compares the temperature with a preset temperature setting value. If the average temperature is higher than the temperature setting value, the threshold value is reset based on the following equation (2). Make settings.

[0030]

[Equation 2] Here, [Constant 1]: LED lighting rate at the maximum value of the number of R / G data determined by the threshold value before adjustment [Constant 2]: Constant that determines the rate of adjustment [Constant 3]: Maximum value of R / G data .

In the case of this embodiment, the following equation 3 is obtained.

[0032]

[Equation 3] Here, K is a constant that determines the adjustment rate. Further, the above adjustment is executed only when the average temperature> the set temperature.

In this way, the lighting rate corresponding to the threshold value obtained by the threshold value setting unit 3 is given to the data conversion unit 1, and the data conversion unit 1 performs data conversion based on the newly set threshold value. . As a result, the threshold value is automatically adjusted in the direction in which the screen surface temperature is suppressed, so that the surface temperature of the LED display device 4 does not excessively rise, and damage to the LED element and reduction in life are suppressed. Will be able to.

The invention of claim 2 is not limited to the above-mentioned embodiment, and in particular, as the method of the threshold value resetting process performed by the threshold value setting unit 3, the formula 2 is not used, and [set temperature]
A method of simply lowering the brightness of the entire display screen based on the value of / [average temperature] may be used, or another method may be used.

Next, an embodiment of the LED display device of the invention of claim 3 will be described in detail with reference to FIG. The LED display device shown in FIG. 5 uses a data conversion unit 1 that dynamically adjusts a threshold value when converting a video signal to be displayed on a display screen for LED display, and data converted by the data conversion unit 1. A brightness measuring unit 2 that measures the average brightness of the entire display screen, a temperature measuring unit 5 that measures the average surface temperature of the entire display screen, and a level of average brightness measured by the brightness measuring unit 2 and the temperature measuring unit 5. A threshold setting unit 3 is provided for making a composite decision based on the level of the average surface temperature and setting the threshold used in the data conversion unit 1.

Also in this embodiment, the data converter 1 converts the video signal into an LED display signal and outputs it to the LED display device 5 as in the embodiment shown in FIG. From the data converted by the data conversion unit 1, the average brightness and brightness histogram of the entire screen are calculated, and the temperature measurement unit 5 displays a plurality of display screens of the LED display device 4 as in the embodiment shown in FIG. The average temperature of the entire display screen is measured based on the signal from the temperature sensor arranged at the appropriate position.

The threshold value setting unit 3 includes the brightness measuring unit 2
If the average brightness becomes brighter than the preset brightness, or the average temperature becomes higher than the preset temperature, using the obtained brightness data and the temperature data obtained from the temperature measurement unit 5. If
The threshold value is reset in the same manner as in the embodiment of FIG. 1, or the threshold value is reset in the same manner as in the embodiment of FIG. 4, and the average brightness and the average temperature become larger than the respective set values. In this case, the process based on the temperature or the process based on the brightness is prioritized, the threshold value is reset based on the process with the higher priority, and the result is given to the data conversion unit 1. There is.

Next, the operation of the LED display device having the above structure will be described. The brightness measuring unit 2 measures a brightness histogram divided into 256 stages from the data converted by the data converting unit 1 as in the embodiment of FIG.
Further, the average luminance value is calculated from the obtained luminance histogram data, and is given to the threshold value setting unit 3. Also, the temperature measuring unit 5
Receives temperature signals from temperature sensors arranged at a plurality of appropriate places of the LED display device 4, calculates an average temperature of the entire display screen, and supplies this to the threshold value setting unit 3.

The threshold value setting section 3 judges whether or not the average brightness value obtained by the brightness measuring section 2 is larger than the set brightness, and the average temperature obtained by the temperature measuring section 5 is higher than the set temperature. Determine whether

If the average brightness is higher than the set brightness but the average temperature is lower than the set temperature, the threshold value is reset based on the average brightness.
The threshold value resetting process based on the average luminance is performed by the method shown in FIGS. On the other hand, when the average temperature is higher than the set temperature but the average brightness is smaller than the set brightness, the threshold value reset process based on the average temperature is performed. This threshold value resetting process based on the average temperature is the same as that of the embodiment shown in FIG. 4, and the threshold value is reset based on the equation (2).

Further, when both the average brightness and the average temperature are higher than the respective set values, the average temperature is prioritized and the threshold value is reset based on the equation (2).

Therefore, the data conversion unit 1 performs the data conversion using the threshold value calculated by the threshold value setting unit 3 to suppress the brightness of the entire display screen and convert the video signal of a relatively bright video data. Even if it is input to the part 1, it becomes possible to automatically suppress the brightness and display it on the LED display screen, suppress the temperature rise of the LED element, damage the element due to excessive temperature rise, and shorten the element life. Can be suppressed. In the case of this embodiment, the average brightness may be prioritized instead of the average temperature, and the threshold value reset processing based on the brightness may be performed.

Further, the method of resetting the threshold value by the measured brightness and the method of resetting the threshold value by the measured temperature are not limited to the method of the above-mentioned embodiment, but in the first embodiment and the second embodiment. Other methods may be used.

Next, an embodiment of the LED display device according to the invention of claim 4 will be described with reference to FIG. In each of the above embodiments, it is possible that the brightness of the display screen is changed in response to noise-like data, but in such a case, the brightness of the image frequently changes and the screen flickers. , It can be hard to see.

Therefore, the LED display device according to the fourth aspect of the present invention is configured so that the execution frequency of the threshold value resetting process can be suppressed. That is, L of the embodiment shown in FIG.
The ED display device displays the video signal to be displayed on the display screen with LE.
A data conversion unit 1 that dynamically adjusts a threshold value when converting for D display, a brightness measurement unit 2 that measures the average brightness of the entire display screen from the data converted by this data conversion unit 1, an entire display screen Temperature measurement unit 5 for measuring the average surface temperature of, the average brightness measured by the brightness measurement unit 2 and the average surface temperature measured by the temperature measurement unit 5 are combined to determine data conversion The threshold value setting unit 3 for variably setting the threshold value used in the unit 1, and in addition to these, the process control unit 6 for performing the threshold value update setting of the threshold value setting unit 3 when a predetermined condition is satisfied. It consists of

Therefore, in the LED display device of the above embodiment, the processing control unit 6 controls the execution of the threshold value processing at a certain time interval, and the output from the data conversion unit 1 or the video signal before conversion is used. Count the number of frames,
Alternatively, a processing instruction signal is output to the brightness measuring unit 2 and the temperature measuring unit 5 so that a timer is provided in itself to count a predetermined number of frames or to perform threshold processing each time the timer counts a predetermined time. .

In response to the execution command from the processing control unit 6, the brightness measuring unit 2 measures the average brightness of the display screen and the temperature measuring unit 5 displays the same as in the embodiment shown in FIG. The average temperature of the screen is measured, and the threshold value setting unit 3 receives these measured values and performs the threshold value reset processing based on the brightness or the threshold value reset processing based on the surface temperature. It is given to the conversion unit 1.

As a result, the threshold value is updated and set at regular time intervals, and the threshold value is not frequently updated and set in response to noise-like data, and the LED element is not used. It is possible to prevent damage to the LED and shorten the life of the LED, and to prevent the visibility of the LED display from being impaired.

In the case of the embodiment of the invention of claim 4, the processing control unit 6 does not perform the threshold value setting process at regular intervals, but outputs from the data conversion unit 1 or before conversion. The brightness difference value between frames is calculated from the video signal, and it is determined that the brightness change has occurred only when the difference value becomes larger than the set value, and the threshold value process is controlled to be executed. Good.

Further, the invention of claim 4 is not limited to the embodiment shown in FIG. 6, and in the LED display device of FIG. In the LED display device of FIG. 4 shown as the embodiment of the invention of claim 2, the processing control unit 6 is placed in front of the temperature measuring unit 5, and the threshold setting unit 3 is placed. It is also possible to execute the process at regular time intervals or only when the luminance change between frames becomes large.

[0051]

As described above, according to the invention of claim 1,
When converting the video signal to be displayed on the display screen by the data conversion unit for LED display, the brightness measurement unit measures the average brightness of the entire display screen from the converted data, and the threshold setting unit measures the brightness. The threshold value used in the data conversion unit is variably set based on the high and low of the average luminance measured by the unit,
In the data conversion unit, the threshold for converting the video signal to be displayed on the display screen for LED display is dynamically adjusted based on the threshold given by the threshold setting unit. When the average brightness of the rises, the threshold value of the data conversion unit is dynamically adjusted in the direction of suppressing the average brightness, the increase of the average brightness of the display screen is suppressed, and thus the temperature increase of the LED element is suppressed.
It is possible to prevent damage to the element and reduction in the life of the element.

According to the second aspect of the present invention, when converting the video signal to be displayed on the display screen by the data conversion unit for the LED display, the temperature measuring unit measures the average surface temperature of the entire display screen, and the threshold value is measured. The value setting unit variably sets the threshold value used in the data conversion unit based on the level of the average surface temperature measured by the temperature measurement unit, and in the data conversion unit, based on the threshold value given by the threshold value setting unit. Since the threshold for converting the video signal to be displayed on the display screen for LED display is dynamically adjusted, if the average surface temperature of the display screen rises, increase the average surface temperature. It is possible to dynamically adjust the threshold value of the data conversion unit in the suppressing direction, suppress the temperature rise of the LED element, and suppress the damage of the element and the reduction of the life of the element.

According to the third aspect of the present invention, when converting the video signal to be displayed on the display screen by the data conversion unit for LED display, the brightness measurement unit displays the data based on the data converted by the data conversion unit. Measure the average brightness of the entire screen,
The temperature measurement unit measures the average surface temperature of the entire display screen, and the threshold value setting unit determines the average brightness measured by the brightness measurement unit and the average surface temperature measured by the temperature measurement unit. , By making a composite decision and variably setting the threshold value used in the data conversion unit, in the data conversion unit, based on the threshold value given by the threshold value setting unit, the video signal to be displayed on the display screen is used for LED display. Since the threshold for conversion is adjusted dynamically, if the average brightness of the display screen rises, and if the average surface temperature rises, the data conversion tends to suppress the rise of the average surface temperature. It is possible to dynamically adjust the threshold value of the portion, suppress the temperature rise of the LED element, and prevent the element from being damaged or the life of the element from being shortened.

According to the invention of claim 4, in the LED display device according to any one of claims 1 to 3, further, the processing control for performing the threshold value update setting of the threshold value setting portion when a predetermined condition is satisfied. In addition to the above effects, the threshold value of the data conversion unit is changed at fixed time intervals or only when the brightness increase or temperature increase greatly exceeds a predetermined value. Therefore, frequent changes in the brightness of the display screen can be avoided as much as possible, and the visibility of the display screen can be maintained.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an embodiment of the invention of claim 1;

FIG. 2 is an explanatory diagram showing the operation of the luminance measuring unit of the above embodiment.

FIG. 3 is an explanatory diagram showing a threshold setting process of a threshold setting unit of the above embodiment.

FIG. 4 is a functional block diagram of an embodiment of the invention of claim 2;

FIG. 5 is a functional block diagram of an embodiment of the invention of claim 3;

FIG. 6 is a functional block diagram of an embodiment of the invention of claim 4;

[Explanation of symbols]

 1 data conversion unit 2 brightness measurement unit 3 threshold setting unit 4 LED display device 5 temperature measurement unit 6 processing control unit

Claims (4)

[Claims] 1. LE in dot units or module units
In an LED display device in which a large number of D elements are arranged to form a display screen, a data conversion unit that dynamically adjusts a threshold value when converting a video signal to be displayed on the display screen for LED display, A brightness measurement unit that measures the average brightness of the entire display screen from the data converted by the data conversion unit, and the threshold value used in the data conversion unit is variably set depending on the level of the average brightness measured by the brightness measurement unit. And a threshold value setting unit for controlling the LED display device. 2. LE in dot units or module units
In an LED display device in which a large number of D elements are arranged to form a display screen, a data conversion unit that dynamically adjusts a threshold value when converting a video signal to be displayed on the display screen for LED display, A temperature measuring unit that measures the average surface temperature of the entire display screen; and a threshold setting unit that variably sets the threshold value used in the data conversion unit, depending on the height of the average surface temperature measured by the temperature measuring unit. An LED display device comprising: 3. LE in dot units or module units
In an LED display device in which a large number of D elements are arranged to form a display screen, a data conversion unit that dynamically adjusts a threshold value when converting a video signal to be displayed on the display screen for LED display, A brightness measurement unit that measures the average brightness of the entire display screen from the data converted by the data conversion unit, a temperature measurement unit that measures the average surface temperature of the entire display screen, and an average brightness measured by the brightness measurement unit. And a threshold value setting unit that variably sets a threshold value used in the data conversion unit based on the height of the average surface temperature measured by the temperature measurement unit and the average surface temperature measured by the temperature measurement unit. Display device. 4. The LED display device according to claim 1, further comprising a processing control unit that performs the threshold update setting of the threshold setting unit when a predetermined condition is satisfied.