WO2022074784A1 - Système d'affichage à del - Google Patents

Système d'affichage à del Download PDF

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Publication number
WO2022074784A1
WO2022074784A1 PCT/JP2020/038126 JP2020038126W WO2022074784A1 WO 2022074784 A1 WO2022074784 A1 WO 2022074784A1 JP 2020038126 W JP2020038126 W JP 2020038126W WO 2022074784 A1 WO2022074784 A1 WO 2022074784A1
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WIPO (PCT)
Prior art keywords
brightness
led
luminance
led display
unit
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PCT/JP2020/038126
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English (en)
Japanese (ja)
Inventor
直樹 菅野
洋和 田口
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三菱電機株式会社
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Priority to PCT/JP2020/038126 priority Critical patent/WO2022074784A1/fr
Publication of WO2022074784A1 publication Critical patent/WO2022074784A1/fr

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]

Definitions

  • the present disclosure relates to an LED display system including a plurality of LED display devices.
  • LED display devices that display images using multiple LEDs (Light Emitting Diodes) are used in many applications such as outdoor and indoor advertisement display due to technological development and cost reduction of LEDs.
  • LED display devices have been mainly used for displaying natural images and moving images of animation.
  • LED display devices are used indoors, in conference rooms, or for monitoring purposes. It is also used for such purposes.
  • LED display devices used in surveillance applications often display images of personal computers that are close to still images.
  • the method of adjusting the brightness of the image displayed by the LED display device includes a method of adjusting the duty ratio of the LED controlled by PWM (Pulse Width Modulation) and a method of adjusting the current value for driving the LED. There is.
  • PWM Pulse Width Modulation
  • the displayable gradation may be lowered. Therefore, in order to maintain good image quality not only when the display device displays a high-gradation image but also when displaying a low-gradation image, the brightness of the image is adjusted by the drive current value of the LED. Is preferable.
  • the rank attached to the LED in this way is called the BIN rank.
  • the brightness of the LED decreases as the cumulative lighting time increases.
  • the cumulative lighting time of each LED is different, and further, the brightness reduction rate of each LED is different.
  • the cumulative lighting time of each LED becomes longer, the brightness variation and the chromaticity variation of the pixels occur.
  • the brightness of the LED display surface that is, the surface for displaying a desired image toward the observer
  • the reference LED is mounted on the surface of the two surfaces of the circuit board opposite to the surface on which the plurality of LEDs constituting the LED display surface are mounted.
  • the reference LED which is driven in the same manner as the driving of a plurality of LEDs mounted on the LED display surface side, deteriorates in the same manner as each LED mounted on the LED display surface side.
  • the LED display device detects the brightness of the reference LED by the optical sensor, measures the brightness reduction rate, and corrects the brightness of each LED mounted on the LED display surface side based on the brightness reduction rate. With this technique, the LED display device can correct the variation in brightness and chromaticity of the LED display surface due to the difference in the lighting time of the LED.
  • Patent Document 1 when one reference LED is controlled to emit light with a fixed drive current value for one circuit board on which a plurality of LEDs constituting the display surface are mounted, the following The problem arises. That is, there is no problem if all the LEDs mounted on one circuit board have the same BIN rank, but in reality, a plurality of BIN rank LEDs are mounted. In this case, it is difficult to correct the brightness of each LED based on the brightness reduction rate of one reference LED because a difference in deterioration occurs due to a difference in the BIN rank of the LED.
  • the present disclosure has been made to solve such a problem, and an object of the present disclosure is to provide an LED display system capable of reducing brightness variation and chromaticity variation of a display unit.
  • the LED display system is arranged in a matrix, and has a plurality of LED display devices having one screen in which the display surfaces of each are arranged, and an image is displayed on each LED display device. It is an LED display system including an LED display control device that distributes a signal and controls to display an image on one screen.
  • Each LED display device is provided on a display surface and corresponds to each of a plurality of BIN ranks.
  • the first display unit having a plurality of first LEDs
  • the second display unit having a plurality of second LEDs provided on a surface different from the display surface and corresponding to the same BIN rank as each first LED, and the brightness of each second LED.
  • the brightness measuring unit to be measured the first driving unit that drives each first LED under the first driving condition based on the video signal, and the second LED under the second driving condition of one of a plurality of predetermined second driving conditions.
  • the LED display control device acquires the measurement result of the brightness of each second LED driven under different second drive conditions from each LED display device, and each is based on the measurement result of the brightness.
  • the brightness reduction characteristic calculation unit that calculates the brightness reduction characteristic for the cumulative lighting time of the second LED for each second drive condition and for each BIN rank, and the brightness reduction characteristic of one of the brightness reduction characteristics calculated by the brightness reduction characteristic calculation unit.
  • a luminance correction unit for correcting the luminance of the image included in the video signal for each first LED based on the cumulative lighting time of each first LED is provided, and the LED display control device is provided on each LED display device after the luminance correction. It controls to distribute the video signal and display the video after brightness correction on one screen.
  • the LED display system can reduce the luminance variation and the chromaticity variation of the display unit.
  • FIG. It is a figure which shows the structure of the LED display system by Embodiment 1.
  • FIG. It is a block diagram which shows the internal structure of the LED display device by Embodiment 1.
  • FIG. It is a figure which shows the structure of the 1st display part by Embodiment 1.
  • FIG. It is a figure which shows the structure of the 2nd display part by Embodiment 1.
  • FIG. It is a block diagram which shows the internal structure of the LED display control apparatus by Embodiment 1.
  • FIG. It is a figure which shows an example of the duty ratio of the pulse width in the PWM control by Embodiment 1.
  • FIG. It is a figure which shows an example of the luminance reduction characteristic for every duty ratio by Embodiment 1.
  • FIG. 1 It is a figure which shows an example of the luminance reduction characteristic in a normal luminance mode and a high luminance mode by Embodiment 2.
  • FIG. It is a figure which shows an example of the luminance reduction characteristic when the luminance mode is switched by Embodiment 2.
  • FIG. It is a figure which shows an example of the hardware composition of the LED display control apparatus by Embodiments 1 and 2.
  • FIG. 1 is a diagram showing a configuration of an LED display system according to the first embodiment.
  • the LED display system includes a plurality of LED display devices 100 and an LED display control device 300.
  • the plurality of LED display devices 100 constitute all LED display devices 200 arranged in a matrix.
  • the all LED display device 200 is an array in which a plurality of LED display devices 100 are arranged.
  • the whole LED display device 200 has one screen in which the display surfaces of each of the plurality of LED display devices 100 are arranged.
  • Each LED display device 100 has a display surface of 320 horizontal pixels ⁇ 180 vertical pixels. Therefore, the all LED display device 200 has one screen of Full HD composed of 1920 ⁇ 1080 pixels.
  • the LED display system can display an image including characters, figures, images, and the like on one screen of all LED display devices 200.
  • the LED display control device 300 distributes a video signal to each LED display device 100, and displays a video on one screen of all the LED display devices 200 by communicating the control signal with each LED display device 100. Control to do.
  • the all LED display devices 200 are the LED display devices 100 having IDs 1 to 12, the LED display devices 100 having IDs 13 to 24, and the LED display devices 100 having IDs 25 to 36. It is divided into three groups. Each group includes 12 LED display devices 100. The 12 LED display devices 100 in each group are daisy-chained to the LED display control device 300.
  • the LED display control device 300 can efficiently distribute video signals and communicate control signals by connecting in a daisy chain.
  • the LED display control device 300 is, for example, an LED control unit.
  • FIG. 2 is a block diagram showing an internal configuration of one LED display device 100 according to the first embodiment.
  • the LED display device 100 includes a first display unit 1, a second display unit 3, a video signal processing unit 6, a first drive unit 2, a communication unit 7, a second drive unit 4, a brightness measurement unit 5, a microcomputer circuit 8, and an LED display device 100. It has a memory circuit 9. Further, FIG. 2 shows a video input terminal 11 and a control signal terminal 12 as a configuration related to the LED display device 100.
  • the first display unit 1 has a plurality of first LEDs provided on the display surface. Further, the first display unit 1 has a plurality of pixels arranged in a matrix. The first display unit 1 constitutes a part of one screen of all LED display devices 200.
  • FIG. 3 is a diagram showing the configuration of the first display unit 1 according to the first embodiment.
  • the first display unit 1 has a configuration in which 320 pixels 10 are arranged in the horizontal direction and 180 pixels 10 are arranged in the vertical direction.
  • one pixel 10 is composed of three first LEDs 1A that emit light in red (R), green (G), and blue (B) as a set.
  • R red
  • G green
  • B blue
  • any of four BIN ranks (1st BIN rank, 2nd BIN rank, 3rd BIN rank, 4th BIN rank) is used for the 1st LED 1A, and the 1st LED 1A of which BIN rank is used at which position of the 1st display unit 1.
  • BIN ranks 1st BIN rank, 2nd BIN rank, 3rd BIN rank, 4th BIN rank
  • the brightness can be corrected based on the information of the second LED 3A (see FIG. 4) described later.
  • they are arranged together for each BIN rank for easy understanding, but in reality, it is not necessary to arrange the first LEDs 1A of the same BIN rank together. Also, the BIN rank is not fixed at four.
  • the second display unit 3 has at least one second LED provided on a surface different from the display surface.
  • the surface different from the display surface is, for example, a back surface located on the opposite side of the display surface.
  • FIG. 4 is a diagram showing the configuration of the second display unit 3 according to the first embodiment.
  • the second display unit 3 has a configuration in which two pixels 10 are arranged in the horizontal direction and two pixels 10 are arranged in the vertical direction.
  • One pixel 10 in the second display unit 3 comprises three second LEDs 3A that emit light in red (R), green (G), and blue (B) as a set.
  • the second display unit 3 displays for the LED display system to predict the transition of the brightness of the first display unit 1.
  • four different BIN rank pixels 10 are arranged in the second display unit 3. Therefore, the rank of the first LED 1A used for the first display unit is four or less.
  • each second LED 3A of the second display unit 3 when each second LED 3A of the second display unit 3 is driven for the same time under the same drive conditions (for example, the same drive current value) as each first LED 1A of the first display unit 1, each first LED 1A is driven.
  • the transition of the same brightness as the transition of the indicated brightness is shown.
  • the brightness reduction rate of each second LED 3A is the same as or similar to the brightness reduction rate of each first LED 1A.
  • Each of the first LED1A and each second LED3A has the same BIN rank, for example, and has similar characteristics such as luminance and wavelength. When both are driven by the same drive current, the respective brightness reduction rates are the same.
  • the video input terminal 11 receives a video signal from the LED display device 100 or the LED display control device 300 in the previous stage connected in a daisy chain.
  • the video signal is a signal including video data of the video to be displayed by all the LED display devices 200.
  • the video signal processing unit 6 performs processing such as selection processing on the video signal received at the video input terminal 11. In the selection process, the video signal processing unit 6 selects a video area to be displayed by the LED display device 100 including itself from the video included in the video signal.
  • the first drive unit 2 drives each first LED 1A under the first drive condition based on the video signal.
  • the first drive condition includes a condition relating to a duty ratio for PWM control of each first LED 1A.
  • the first drive unit 2 drives each first LED 1A by PWM control for each color based on the signal processed by the video signal processing unit 6.
  • the video in the video region selected by the video signal processing unit 6 is displayed on the first display unit 1.
  • the control signal terminal 12 receives a control signal from the LED display device 100 or the LED display control device 300 in the previous stage connected in a daisy chain.
  • the control signal is, for example, a signal including control data such as a luminance correction coefficient.
  • the communication unit 7 communicates with the LED display control device 300 via the control signal terminal 12 and the like.
  • the communication unit 7 outputs the control signal received from the LED display control device 300 to the microcomputer circuit 8. Further, the communication unit 7 transmits the control signal input from the microcomputer circuit 8 to the LED display control device 300.
  • the second drive unit 4 drives each second LED 3A under the second drive condition, which is one of a plurality of predetermined second drive conditions.
  • the second drive condition includes a condition relating to a duty ratio for PWM control of each second LED 3A.
  • the second drive unit 4 drives each second LED 3A by PWM control at a duty ratio of one of the three predetermined duty ratios.
  • the second drive unit 4 drives each of the second LEDs 3A under different second drive conditions for each of the three groups of the plurality of LED display devices 100.
  • the second drive unit 4 always drives each second LED 3A under one second drive condition.
  • the brightness measuring unit 5 measures the brightness of the second LED 3A for each BIN rank.
  • the brightness measuring unit 5 includes, for example, a light receiving element.
  • the brightness measurement result is output to the microcomputer circuit 8.
  • the microcomputer circuit 8 comprehensively controls the components of the LED display device 100.
  • the microcomputer circuit 8 controls the video signal processing unit 6, the control of the first drive unit 2, the control of the communication unit 7, the control of the second drive unit 4, the control of the luminance measurement unit 5, and the memory. It controls reading and writing to the circuit 9.
  • the memory circuit 9 stores various parameters.
  • the various parameters include, for example, the mounting position of each first LED 1A, BIN rank information, an individual brightness correction coefficient which is a coefficient for correcting the brightness, a correction brightness which is the brightness of each first LED 1A corrected by the individual brightness correction coefficient, and the like. Contains the required settings and adjustments for.
  • the individual luminance correction coefficient is a luminance correction coefficient individually obtained for each LED display device 100, and is a luminance correction coefficient for correcting the luminance variation and the chromaticity variation in each LED display device 100.
  • the memory circuit 9 stores the initial value of the individual luminance correction coefficient, the initial value of the corrected luminance, and the BIN rank at the time of shipment from the factory.
  • FIG. 5 is a block diagram showing an internal configuration of the LED display control device 300 according to the first embodiment.
  • the LED display control device 300 includes a video signal processing circuit 30, a control circuit 20, and a video division transfer circuit 40. Further, FIG. 5 shows a video signal input terminal 50, an external signal terminal 60, a video output terminal 70, and a control signal terminal 80 as configurations related to the LED display control device 300.
  • the video signal input terminal 50 receives a video signal from the outside.
  • the video signal processing circuit 30 performs processing such as gamma correction on the video signal received at the video signal input terminal 50.
  • the external signal terminal 60 receives a control signal for controlling the LED display control device 300 and each LED display device 100 from an external PC (Personal Computer) or the like.
  • the control circuit 20 transmits a control signal to the plurality of LED display devices 100, and receives a control signal from the plurality of LED display devices 100. As a result, the control circuit 20 controls all the LED display devices 200. Further, the control circuit 20 controls the correction of the video signal based on the control signal received by the external signal terminal 60 and the control signal transmitted from the communication unit 7 of each LED display device 100.
  • the video division transfer circuit 40 divides the video signal corrected by the control circuit 20 into three video signals corresponding to the video to be displayed by the LED display device 100 belonging to each group.
  • the video division transfer circuit 40 transmits three video signals to the LED display devices 100 of each of the three groups.
  • the control circuit 20 includes a lighting time calculation unit 24, a parameter storage unit 25, a brightness reduction characteristic calculation unit 21, a brightness correction unit 22, an external communication control unit 26, and an internal communication control unit 27. Further, the luminance correction unit 22 has a correction coefficient calculation unit 23.
  • the lighting time calculation unit 24 calculates and stores the cumulative lighting time and the average duty ratio of each first LED 1A in the 1920 ⁇ 1080 pixels of all the LED display devices 200 at regular time intervals.
  • the internal communication control unit 27 stores the parameters included in the control signal received by the control signal terminal 80 in the parameter storage unit 25, or outputs the parameters to the external communication control unit 26, the brightness correction unit 22, or the brightness reduction characteristic calculation unit 21. To do. Further, the internal communication control unit 27 transmits the parameters stored in the parameter storage unit 25 to the plurality of LED display devices 100 via the control signal terminal 80. Alternatively, the internal communication control unit 27 transmits parameters and the like input from the external communication control unit 26, the brightness correction unit 22, or the brightness reduction characteristic calculation unit 21 to the plurality of LED display devices 100 via the control signal terminal 80. do.
  • the brightness reduction characteristic calculation unit 21 acquires the measurement result of the brightness of the second LED 3A, which is driven under different second drive conditions, from the plurality of LED display devices 100.
  • the brightness reduction characteristic calculation unit 21 calculates the brightness reduction characteristic with respect to the cumulative lighting time of the second LED 3A for each of a plurality of predetermined second drive conditions, and calculates a plurality of brightness reduction characteristics for each BIN rank.
  • the luminance correction unit 22 corrects the luminance of the video signal processed by the video signal processing circuit 30.
  • the brightness correction unit 22 corrects the brightness of the video signal for each first LED 1A based on the brightness reduction characteristic of one of the plurality of brightness reduction characteristics and the cumulative lighting time of each first LED 1A.
  • the luminance correction unit 22 selects, for example, one luminance lowering characteristic based on the first driving condition. That is, the luminance correction unit 22 selects the luminance lowering characteristic driven by the duty ratio close to the average duty ratio of the first LED 1A.
  • the luminance measuring unit 5 measures the second LED 3A having the same BIN rank as the first BIN rank, and derives the initial correction value of the first BIN rank. By applying the correction value to the first LED 1A, the first display unit 1 is corrected. The same applies to the first LED 1A of another BIN rank.
  • the correction coefficient calculation unit 23 calculates the first brightness correction coefficient for uniformly correcting the brightness on one screen of all the LED display devices 200. At this time, the correction coefficient calculation unit 23 calculates the first luminance correction coefficient based on the individual luminance correction coefficient in each LED display device 100. For example, the correction coefficient calculation unit 23 calculates the first brightness correction coefficient so that the brightness on one screen becomes uniform based on the individual brightness correction coefficient and the correction brightness acquired from the plurality of LED display devices 100. Further, the correction coefficient calculation unit 23 calculates the second brightness correction coefficient corrected by the first brightness correction coefficient based on the cumulative lighting time of each first LED 1A in one brightness reduction characteristic. The luminance correction unit 22 corrects the luminance of the image included in the video signal for each first LED 1A by the second luminance correction coefficient.
  • the external communication control unit 26 stores the parameters included in the control signal received by the external signal terminal 60 in the parameter storage unit 25 and outputs them to the internal communication control unit 27. Further, the external communication control unit 26 transmits the parameters stored in the parameter storage unit 25 or the parameters input from the internal communication control unit 27 to the outside via the external signal terminal 60.
  • Luminance correction is performed for each BIN rank.
  • the memory circuit 9 stores the individual brightness correction coefficient and the initial value of the correction brightness at the time of shipment from the factory.
  • the individual luminance correction coefficient and the corrected luminance are obtained, for example, by measuring the luminance of each first LED 1A corresponding to each of R, G, and B in each pixel 10.
  • the following equation (1) shows the individual luminance correction coefficients Cr (uh, uv), Cg (uh, uv), and Cb (uh, uv).
  • Yr (uh, uv), Yg (uh, uv), and Yb (uh, uv) are R luminance, G luminance, and B luminance before correction of the first LED 1A, respectively.
  • Yr (uh, uv), Yg (uh, uv), and Yb (uh, uv) are, for example, all the first LEDs 1A in one LED display device 100 are lit with the maximum gradation.
  • Yr_min, Yg_min, and Yb_min correspond to the minimum luminance among those Yr (uh, uv), Yg (uh, uv), and Yb (uh, uv).
  • the brightness (corrected brightness) of R, G, and B of each first LED 1A corrected by the individual brightness correction coefficient is uniform to Yr_min, Yg_min, and Yb_min, respectively. That is, the brightness of the display surface of each LED display device 100 becomes uniform because the brightness of the first LED 1A, which has a higher brightness than the minimum brightness, decreases.
  • the memory circuit 9 stores the individual luminance correction coefficients Cr (uh, uv), Cg (uh, uv), Cb (uh, uv) and the corrected luminance Yr_min, Yg_min, Yb_min. Under the control of the microcomputer circuit 8, the communication unit 7 transmits the individual luminance correction coefficient and the luminance correction stored in the memory circuit 9 to the LED display control device 300.
  • the LED display control device 300 associates the ID number of each LED display device 100 with the coordinate position of the pixel 10 on the entire screen of 1920 ⁇ 1080 pixels.
  • the following equation (2) shows the coordinate IDn (h0, v0) of the pixel 10 located at the upper left of each LED display device 100.
  • n is an ID number.
  • the LED display control device 300 acquires the individual luminance correction coefficient and the corrected luminance from each LED display device 100.
  • the correction coefficient calculation unit 23 obtains the first brightness correction coefficient of the entire screen composed of 1920 ⁇ 1080 pixels based on the individual brightness correction coefficient and the correction brightness. More specifically, the correction coefficient calculation unit 23 obtains the first luminance correction coefficient by multiplying the individual luminance correction coefficient by the correction coefficient obtained from the corrected luminance.
  • the first luminance correction coefficients Cr0 (h, v), Cg0 (h, v), and Cb0 (h, v) in each LED display device 100 are represented by the following equations (3) to (9). It should be noted that the formulas (3) to (9) show formulas for obtaining the first luminance correction coefficient of the LED display device 100 corresponding to a typical ID number. Similarly, the first luminance correction coefficient of the LED display device 100 corresponding to the ID number not shown in each of the following equations can be obtained.
  • IDn_Cr (h, v), IDn_Cg (h, v), and IDn_Cb (h, v) are individual luminance correction coefficients of each LED display device 100 received by the LED display control device 300.
  • IDn_Yr_min, IDn_Yg_min, and IDn_Yb_min are the corrected luminances of each LED display device 100 received by the LED display control device 300.
  • Unit_Yr_min, Unit_Yg_min, and Unit_Yb_min are the minimum values of the corrected luminance in all the LED display devices 200.
  • Unit_Yr_min / IDn_Yr_min, Unit_Yg_min / IDn_Yg_min, Unit_Yb_min / IDn_Yb_min correspond to the above-mentioned correction coefficients.
  • the correction coefficient calculation unit 23 obtains the first luminance correction coefficient by multiplying the individual luminance correction coefficient by the correction coefficient.
  • the parameter storage unit 25 stores these calculated first luminance correction coefficients.
  • the brightness of the display surface of each LED display device 100 can already be made uniform by the individual brightness correction coefficient.
  • the brightness correction unit 22 can further make the brightness of one screen of all the LED display devices 200 uniform by the first brightness correction coefficient.
  • the luminance correction unit 22 can set the minimum luminance value in one screen of all the LED display devices 200 as the reference value of the luminance of all the LED display devices 200.
  • the LED display control device 300 can reduce the luminance variation and the chromaticity variation among the plurality of LED display devices 100 by the first luminance correction coefficient.
  • the brightness correction unit 22 corrects the brightness of each first LED 1A by the second brightness correction coefficient corrected by the first brightness correction coefficient in order to further reduce the brightness variation.
  • the second brightness correction coefficient is a brightness correction in which the first brightness correction coefficient is corrected based on the cumulative lighting time of all the LED display devices 200 and the brightness measurement result of the second display unit 3 in each LED display device 100. It is a coefficient.
  • the first drive unit 2 of each LED display device 100 drives a plurality of first LEDs 1A by a PWM method based on video data values. As a result, the brightness of the plurality of first LEDs 1A is controlled.
  • FIG. 6 is a diagram showing an example of the duty ratio of the pulse width in PWM control.
  • FIG. 6 shows, in order from the top, a waveform PW1 having a basic period and a duty ratio of 100%, a waveform PW2 having a duty ratio of 80%, and a waveform PW3 having a duty ratio of 60%.
  • the basic period of PWM is one frame period or less of the video signal.
  • the first drive unit 2 changes the duty ratio based on the luminance information included in the video signal, that is, changes the lighting period and the extinguishing period per unit time of each first LED 1A.
  • the first drive unit 2 can adjust the brightness of each color recognized by the human eye by changing the duty ratio for each color.
  • the first driving unit 2 drives each of the first LEDs 1A at a duty ratio corresponding to the luminance corrected for each of the first LEDs 1A. That is, the lighting period and the extinguishing period per unit time are changed. As a result, each first LED 1A lights up with the corrected luminance.
  • the LED display system performs the display operation, that is, the drive of the first display unit 1, and the display operation, that is, the drive of the second display unit 3 in parallel.
  • Each of the first LED1A and each second LED3A in one LED display device 100 is lit under the same environment, and the brightness reduction rates of both are close to each other.
  • the cumulative lighting time of each 1st LED 1A and each 2nd LED 3A is different. Since the lighting of each first LED 1A is controlled based on the image displayed on the first display unit 1, there are many times when the first LED 1A is not lit. On the other hand, the lighting of each of the second LEDs 3A is not based on the image displayed on the first display unit 1, but is constantly controlled by one of a plurality of predetermined duty ratios. That is, each second LED 3A is always lit at a constant duty ratio. Further, since the lighting of each first LED 1A is controlled based on the brightness of the image, the cumulative lighting time differs for each pixel 10. That is, there is a difference in the cumulative lighting time of each first LED 1A.
  • FIG. 7 is a diagram showing an example of luminance reduction characteristics for each duty ratio in the first embodiment.
  • the brightness reduction characteristic is the relationship between the cumulative lighting time and the brightness reduction rate.
  • FIG. 7 shows the luminance reduction characteristics when the second LED 3A is turned on at duty ratios of 100%, 80%, and 60%, respectively.
  • a logarithmic scale is applied to the scale of the cumulative lighting time in FIG. 7.
  • the higher the duty ratio the higher the brightness of the second LED 3A, so that the heat load due to the temperature rise due to light emission is large.
  • the brightness reduction rate of the second LED 3A becomes large.
  • the lower the duty ratio the smaller the temperature rise due to the light emission of the second LED 3A. Since the decrease in brightness due to the temperature rise can be ignored, the variation in the rate of decrease in brightness depending on the change in the duty ratio is reduced.
  • the second LED 3A and the first LED 1A have the same luminance lowering characteristics. Therefore, the brightness of the first LED 1A also decreases according to the cumulative lighting time, similar to the brightness decrease characteristic shown in FIG. 7.
  • the LED display system according to the first embodiment corrects the brightness of each first LED 1A based on the cumulative lighting time of each first LED 1A.
  • a correction operation specifically, the brightness correction operation after the brightness correction at the time of initial installation will be described in detail.
  • the LED display system controls the drive of the second LED 3A as follows.
  • the second LED 3A in the LED display devices 100 of to 36 is driven by a duty ratio of 60%.
  • the brightness measurement result of the second LED 3A measured by the brightness measuring unit 5 is input to the microcomputer circuit 8.
  • the microcomputer circuit 8 calculates the brightness reduction rate of the second LED 3A from the initial value of the brightness measurement result of the second LED 3A and the current brightness measurement result. In each first BIN rank of the plurality of LED display devices 100, the brightness reduction rate of the second LED 3A is calculated.
  • the brightness reduction characteristic calculation unit 21 acquires the brightness reduction rate of the second LED 3A from each LED display device 100 via the communication unit 7. That is, the luminance reduction characteristic calculation unit 21 acquires a plurality of luminance reduction rates corresponding to the second LED 3A of the first BIN rank, each of which is driven by a different duty ratio.
  • the brightness reduction characteristic calculation unit 21 generates a brightness reduction rate table based on the energization time and the brightness reduction rate of each LED display device 100. At this time, the luminance reduction characteristic calculation unit 21 generates a luminance reduction rate table for each duty ratio.
  • the parameter storage unit 25 stores the generated luminance reduction rate table.
  • the brightness reduction characteristic calculation unit 21 updates the brightness reduction rate table at any time with the passage of time, and the parameter storage unit 25 stores the updated brightness reduction rate table.
  • the brightness reduction characteristic calculation unit 21 receives the brightness reduction rate from each LED display device 100 every hour and updates the brightness reduction rate table.
  • the brightness reduction characteristic calculation unit 21 calculates the average value of the 12 brightness reduction rates of the first BIN rank obtained from the 12 LED display devices 100, and generates a brightness reduction rate table for each duty ratio.
  • the lighting time calculation unit 24 determines the average duty ratio, the cumulative lighting time (Tr, Tg, Tb) for each color of the first LED 1A of the first BIN rank in all the LED display devices 200, and the cumulative energization time of the LED display device 100. , Memorize every fixed unit time. The lighting time calculation unit 24 obtains the average duty ratio and the cumulative lighting time based on the output of the brightness correction unit 22. For example, when the unit energization time is 1 hour and the duty ratio in the unit energization time is 10% (that is, the brightness level is 10%), the lighting time calculation unit 24 has 0.1 hour every hour. Add the lighting time to the cumulative lighting time. Further, the lighting time calculation unit 24 calculates the average duty ratio by dividing the cumulative lighting time of the first LED 1A of each first BIN rank by the cumulative energization time of the LED display device 100.
  • the correction coefficient calculation unit 23 is based on the cumulative lighting time obtained by the lighting time calculation unit 24 and the luminance reduction rate table stored in the parameter storage unit 25, and the LED of the first BIN rank of all the LED display devices 200. Find the brightness maintenance factor of. At this time, the correction coefficient calculation unit 23 obtains the luminance maintenance rate for each color.
  • the R luminance maintenance rate Pr (h, v) of each pixel 10 is obtained from the following equations (10) to (12).
  • the G luminance maintenance rate Pg (h, v) of each pixel 10 is obtained from the following equations (13) to (15).
  • the B luminance maintenance rate Pb (h, v) of each pixel 10 is obtained from the following equations (16) to (18).
  • FPr1 (t), FPg1 (t), and FPb1 (t) are the R luminance maintenance rate per cumulative lighting time at a duty ratio of 100% obtained from the luminance measurement results of each second display unit 3, G.
  • the brightness maintenance rate and the B brightness maintenance rate are the R luminance maintenance rate, the G luminance retention rate, and the B luminance retention rate at a duty ratio of 80%, respectively.
  • FPr3 (t), FPg3 (t), and FPb3 (t) are the R luminance maintenance rate, the G luminance maintenance rate, and the B luminance maintenance rate at a duty ratio of 60%, respectively.
  • Tr (h, v), Tg (h, v), and Tb (h, v) are the cumulative lighting times of the first LED 1A for each color.
  • Dr (h, v), Dg (h, v), and Db (h, v) are the average duty ratios of the first LED 1A for each color.
  • h is a horizontal pixel position (0 to 1919)
  • v is a vertical pixel position (0 to 1079).
  • Equation (10) shows the R luminance maintenance rate Pr (h, v) when Dr (h, v)> 80%.
  • Equation (11) shows the R luminance maintenance rate Pr (h, v) when 80% ⁇ Dr (h, v)> 60%.
  • Equation (12) shows the R luminance maintenance rate Pr (h, v) when 60% ⁇ Dr (h, v).
  • Equation (13) shows the G luminance maintenance rate Pg (h, v) when Dg (h, v)> 80%.
  • Equation (14) shows the G luminance maintenance rate Pg (h, v) when 80% ⁇ Dg (h, v)> 60%.
  • Equation (15) shows the G luminance maintenance rate Pg (h, v) when 60% ⁇ Dg (h, v).
  • Equation (16) shows the B brightness maintenance rate Pb (h, v) when Db (h, v)> 80%.
  • Equation (17) shows the B luminance maintenance rate Pb (h, v) when 80% ⁇ Db (h, v)> 60%.
  • Equation (18) shows the B brightness maintenance rate Pb (h, v) when 60% ⁇ Db (h, v).
  • Cumulative lighting time Tr (h, v), Tg (h, v), Tb (h, v) are calculated based on the case where the duty ratio is 100%. Therefore, when the duty ratio is 80%, the value obtained by multiplying the cumulative lighting time by 0.8 times is used, and when the duty ratio is 60%, the value obtained by multiplying the cumulative lighting time by 0.6 times is used. There is.
  • the LED display system uses the first luminance correction coefficients Cr0 (h, v), Cg0 (h, v), Cb0 (h, v). Brightness is corrected by.
  • the relative value of the actual luminance in consideration of the luminance maintenance rate is expressed by the following equation (19).
  • the correction coefficient calculation unit 23 obtains the relative values Qr (h, v), Qg (h, v), and Qb (h, v) of the actual luminance using the above equation (19). Then, the correction coefficient calculation unit 23 obtains the minimum value Qrgb_min of the relative value of the actual luminance in all the pixels of R, G, and B. Further, the correction coefficient calculation unit 23 uses the second brightness correction coefficients Cr1 (h, v), Cg1 (h, v), and Cb1 for correcting the initial brightness variation of the first LED 1A and the decrease in brightness due to the cumulative lighting time. (H, v) is obtained using the following formula (20).
  • the correction coefficient calculation unit 23 obtains the brightness maintenance rate of each first LED 1A of one BIN rank of one LED display device 100 based on the cumulative lighting time of one LED display device 100. At that time, the correction coefficient calculation unit 23 obtains the brightness maintenance rate for each color of the first LED 1A. Similarly, the correction coefficient calculation unit 23 is based on the cumulative lighting time of the other LED display devices 100, the average duty ratio (average brightness), and the brightness reduction rate table actually measured by each LED display device 100. , The brightness maintenance rate of each color of each first LED 1A of the other LED display device 100 is obtained. The same calculation is performed for other BIN ranks to obtain the brightness maintenance rate of each color of each first LED 1A in all the BIN ranks used.
  • the correction coefficient calculation unit 23 sets the first luminance correction coefficients Cr0 (h, v), Cg0 (h, v), and Cb0 (h, v) to the luminance maintenance rate of one LED display device 100 and the other.
  • the second brightness correction coefficients are changed to Cr1 (h, v), Cg1 (h, v), and Cb1 (h, v) based on the brightness maintenance rate of the LED display device 100.
  • the luminance correction unit 22 corrects the luminance of the video data included in the video signal based on the second luminance correction coefficient.
  • the correction coefficient calculation unit 23 calculates the second brightness correction coefficients Cr1 (h, v), Cg1 (h, v), and Cb1 (h, v) and corrects the brightness at regular time cycles (for example, 100 hours). It may be carried out. Alternatively, the correction coefficient calculation unit 23 may perform the calculation and the luminance correction when the luminance decrease occurs.
  • the time when the luminance decrease occurs is, for example, a case where Qrgb_min is 10% or more lower than Qrgb_min at the time of the previous correction.
  • the duty ratios for driving each of the second LEDs 3A are set to three types of 100%, 80%, and 60% for each of the three groups, but the duty ratio is not limited thereto.
  • the duty ratio may be any two or more kinds of duty ratios.
  • the number of BIN ranks used is conditioned on the number of pixels 10 or less used in the second display unit 3 in the LED display device 100.
  • each first LED 1A having two or more BIN ranks is not necessarily driven by a duty ratio of 100%.
  • the LED display system cannot accurately predict the brightness reduction rate in the first display unit 1. As a result, the prediction error of the decrease in brightness becomes large, and the accuracy of uniform brightness of the corrected screen deteriorates.
  • each of the second LED 3A having the same BIN rank as the first LED 1A is driven by a plurality of duty ratios for each of the plurality of LED display devices 100.
  • the LED display system selects a brightness reduction rate table having the most appropriate duty ratio from the average brightness of each pixel 10 and corrects the brightness of each first LED 1A. As a result, the prediction error of the decrease in luminance becomes small, and the accuracy of uniformity of luminance after correction is improved.
  • the luminance correction unit 22 can also correct the luminance by the luminance reduction rate table previously stored in the parameter storage unit 25 at the time of shipment from the factory.
  • the decrease in the brightness of the first LED 1A changes depending on the environmental temperature and the like.
  • the accuracy of the luminance correction is improved by providing the second display unit 3 for the luminance measurement in each LED display device 100.
  • the luminance measurement sequence of each second LED 3A becomes complicated.
  • the second LED 3A in the first embodiment is driven by one duty ratio in one LED display device 100.
  • the LED display control device 300 collects the luminance measurement results of the second LED 3A driven by the duty ratios different from each other from the plurality of LED display devices 100, and calculates the plurality of luminance reduction characteristics. Therefore, the luminance measurement sequence in one LED display device 100 can be simplified.
  • the LED display system is arranged in a matrix, and has a plurality of LED display devices 100 having one screen in which display surfaces of each are arranged, and images are displayed on each LED display device 100. It is provided with an LED display control device 300 that distributes a signal and controls the display of an image on one screen.
  • Each LED display device 100 is provided on a display surface, has a first display unit 1 having a plurality of first LEDs 1A corresponding to each of a plurality of BIN ranks, and is provided on a surface different from the display surface, and is the same as each first LED 1A.
  • a second display unit 3 having a plurality of second LEDs 3A corresponding to BIN ranks, a brightness measuring unit 5 for measuring the brightness of each second LED 3A, and a first drive for driving each first LED 1A under a first driving condition based on a video signal.
  • a unit 2 and a second drive unit 4 that drives each of the second LEDs 3A under the second drive condition of one of a plurality of predetermined second drive conditions are provided.
  • the LED display control device 300 acquires the measurement result of the brightness of each second LED 3A driven under different second drive conditions from each LED display device 100, and based on the measurement result of the brightness, the brightness decreases with respect to the cumulative lighting time of each second LED 3A.
  • the video signal is based on the brightness reduction characteristic calculation unit 21 that calculates the characteristics for each second drive condition and for each BIN rank, the brightness reduction characteristic of one of the plurality of brightness reduction characteristics, and the cumulative lighting time of each first LED 1A. It is provided with a luminance correction unit 22 that corrects the luminance of the included image for each first LED 1A.
  • the LED display control device 300 distributes the image signal after the luminance correction to each LED display device 100 and controls to display the image after the luminance correction on one screen. With such a configuration, the LED display system improves the uniformity of the luminance and chromaticity of the first display unit 1 for displaying an image or the like.
  • the luminance correction unit 22 of the LED display system selects one of the plurality of luminance reduction characteristics based on the first drive condition. With such a configuration, the uniformity of the luminance and chromaticity of the first display unit 1 is improved with high accuracy.
  • the first drive condition includes a condition relating to a duty ratio for PWM control of a plurality of first LEDs 1A.
  • Each of the plurality of predetermined second drive conditions includes a condition regarding a duty ratio for PWM control of at least one second LED 3A.
  • the brightness correction unit 22 of the LED display system calculates a first brightness correction coefficient for uniformly correcting the brightness of each first LED 1A on one screen, and each first LED 1A in one brightness reduction characteristic.
  • the correction coefficient calculation unit 23 for further calculating the second brightness correction coefficient obtained by correcting the first brightness correction coefficient based on the cumulative lighting time of the above is included.
  • the luminance correction unit 22 corrects the luminance of the image included in the video signal for each first LED 1A by the second luminance correction coefficient.
  • each LED has different luminance and chromaticity characteristics depending on the BIN rank. Therefore, when the brightness correction is performed using the brightness reduction rate due to the lighting time of the representative BIN rank LED without considering the BIN rank, the BIN rank LED different from the LED that actually measured the brightness reduction is used. Cannot perform accurate brightness correction.
  • the LED display system according to the first embodiment since the plurality of LEDs constituting the LED display device 100 are corrected for each BIN rank, the uniformity of the brightness and the chromaticity of the first display unit 1 is improved. Can be made to.
  • At least one second LED 3A in the LED display system according to the first embodiment has the same luminance reduction characteristic as the luminance reduction characteristic exhibited by the plurality of first LEDs 1A when driven for the same time under the same drive conditions as the plurality of first LEDs 1A. .. With such a configuration, the LED display system can accurately determine the luminance reduction characteristic, and accurately improve the uniformity of the luminance and chromaticity of the first display unit 1.
  • the first drive unit 2 of each LED display device 100 drives each first LED 1A with a fixed drive current.
  • the LED display system according to the second embodiment corrects the brightness of all the LED display devices 200 by changing the drive current of the LED display device 100.
  • the LED display system switches the drive current flowing through each first LED 1A between two types of luminance modes, a high luminance mode and a normal luminance mode.
  • the drive current value in the high luminance mode is larger than the drive current value in the normal luminance mode.
  • it is operated in the normal brightness mode, and it is operated by switching to the high brightness mode as needed such as in an emergency.
  • the LED display system switches the above modes.
  • the LED display system switches the above mode.
  • the case where it is difficult for the observer to see may be, for example, a case where the content displayed on the first display unit 1 is changed from a dark one to a bright one.
  • the first drive unit 2 adjusts the brightness by changing the drive current values of the plurality of first LEDs 1A at the same time. do. In one luminance mode, the drive current value of each first LED 1A is the same value.
  • the LED display system needs to measure the brightness reduction rate of the second LED 3A in the high luminance mode and the luminance reduction rate of the second LED 3A in the normal luminance mode for each BIN rank.
  • the LED display system controls each LED display device 100 as follows.
  • the brightness reduction characteristic calculation unit 21 acquires the brightness reduction rate of the second LED 3A from each LED display device 100 via the communication unit 7 for each BIN rank.
  • the brightness reduction characteristic calculation unit 21 generates a brightness reduction rate table in the high brightness mode and the normal brightness mode based on the energization time and the brightness reduction rate of each LED display device 100.
  • the luminance reduction characteristic calculation unit 21 generates a luminance reduction rate table for each BIN rank and duty ratio.
  • the parameter storage unit 25 stores the generated luminance reduction rate table.
  • the brightness reduction characteristic calculation unit 21 updates the brightness reduction rate table for each duty ratio at any time with the passage of time. For example, the brightness reduction characteristic calculation unit 21 receives the brightness reduction rate from each LED display device 100 every hour and updates the brightness reduction rate table. There are six LED display devices 100 for one duty ratio.
  • the brightness reduction characteristic calculation unit 21 calculates the average value of the six brightness reduction rates obtained from the six LED display devices 100, and generates a brightness reduction rate table for each BIN rank.
  • the luminance correction method when the operation is fixed to the high luminance mode or the normal luminance mode and the drive current is not switched is the same as that of the first embodiment, and thus the description thereof will be omitted.
  • the brightness correction operation performed by the LED display system will be described.
  • the brightness correction operation performed by the LED display system when the brightness of the first display unit 1 is adjusted during the operation of the LED display system will be described.
  • the correction coefficient calculation unit 23 obtains the brightness reduction rate of all the LED display devices 200 based on the cumulative lighting time obtained by the lighting time calculation unit 24 and the brightness reduction rate table stored in the parameter storage unit 25. .. At this time, the correction coefficient calculation unit 23 obtains the brightness reduction rate for each color.
  • FIG. 8 is a diagram showing an example of luminance reduction characteristics in the normal luminance mode and the high luminance mode in the second embodiment.
  • the brightness reduction rate of the second LED 3A increases.
  • the drive current value in the high luminance mode is larger than the drive current value in the normal luminance mode. Therefore, the heat load due to the temperature rise is also large.
  • the brightness reduction rate of the second LED 3A lit in the high luminance mode is larger than the luminance reduction rate of the second LED 3A lit in the normal luminance mode.
  • each first LED 1A has a brightness reduction rate similar to the brightness reduction rate of each second LED 3A.
  • the brightness of each 1st LED 1A decreases with the cumulative lighting time. Further, when the high brightness mode is switched to the normal brightness mode, the brightness reduction characteristic of each first LED 1A shifts from the brightness reduction characteristic of the high brightness mode to the brightness reduction characteristic of the normal brightness mode. Even if the cumulative lighting times of each other are the same, the brightness reduction rate in the normal luminance mode is different from the luminance reduction rate in the high luminance mode. Therefore, when the brightness correction unit 22 corrects the brightness of the first LED 1A based on the brightness reduction rate of the normal brightness mode in which the same cumulative lighting time has simply elapsed at the time of transition, the degree of progress of the actual brightness reduction rate of the first LED 1A is reached. Get different correction results. That is, the luminance correction unit 22 cannot accurately correct the luminance.
  • the LED display system converts the cumulative lighting time in the high brightness mode immediately before changing the brightness mode into the cumulative lighting time in the corresponding normal brightness mode.
  • the LED display system can accurately predict the luminance reduction rate of the first LED 1A, so that the luminance variation and the chromaticity variation of the first display unit 1 can be reduced.
  • FIG. 9 is a diagram showing an example of the luminance reduction characteristic when the luminance mode is switched in the second embodiment. As an example, FIG. 9 shows only each brightness reduction rate of the cumulative lighting time with respect to the duty ratio of 100%.
  • the correction coefficient calculation unit 23 calculates the cumulative lighting time T1 indicating the luminance reduction rate of 20% in the graph showing the luminance reduction rate in the normal luminance mode. That is, the correction coefficient calculation unit 23 calculates the cumulative lighting time in the normal brightness mode in which the brightness reduction rate corresponding to the brightness reduction rate in the high brightness mode can be obtained.
  • the first LED 1A when the first LED 1A is lit for 10 K hours in the high brightness mode and then for 100 hours in the normal brightness mode, the first LED 1A shows the brightness reduction rate when lit for 20 K hours + 100 hours only in the normal brightness mode.
  • the correction coefficient calculation unit 23 obtains a second brightness correction coefficient by using the brightness reduction rate when the light is turned on for 20 K hours + 100 hours in the normal brightness mode.
  • the R luminance maintenance rate Pr (h, v) is represented by the following equations (21) to (23).
  • FPrh1 (t) is the R luminance maintenance rate per cumulative lighting time in the high luminance mode and the duty ratio of 100%.
  • FPrn1 (t) is an R luminance maintenance rate per cumulative lighting time in a normal luminance mode and a duty ratio of 100%.
  • Prh (h, v) is an R luminance maintenance rate for each pixel 10 in the high luminance mode.
  • Prn (h, v) is the R luminance maintenance rate in the normal luminance mode.
  • t0 is the cumulative lighting time in the high brightness mode.
  • Equation (22) shows the R luminance maintenance rate (h, v) in the normal luminance mode when the high luminance mode is switched to the normal luminance mode.
  • the correction coefficient calculation unit 23 obtains T1 satisfying the equation (22).
  • Equation (23) shows the R luminance maintenance rate (h, v) after switching to the normal luminance mode.
  • t1 is the cumulative lighting time after switching to the normal luminance mode.
  • the luminance mode for driving the second LED 3A of the second display unit 3 is not limited to two types of luminance modes such as the high luminance mode and the normal luminance mode.
  • the LED display system may drive each of the second LEDs 3A included in the plurality of LED display devices 100 in three or more kinds of luminance modes.
  • the LED display system when the brightness mode is changed for each BIN rank, the cumulative lighting time before the change of the brightness mode is converted into the cumulative lighting time after the change of the brightness mode.
  • the LED display system can accurately predict the luminance retention rate of the first LED 1A, so that the luminance variation and the chromaticity variation of the first display unit 1 can be reduced.
  • the luminance correction unit 22 can also correct the luminance by the luminance reduction rate table stored in advance in the parameter storage unit 25 at the time of shipment from the factory.
  • the decrease in the brightness of the first LED 1A changes depending on the environmental temperature and the like.
  • the accuracy of the luminance correction is improved by providing the second display unit 3 for the luminance measurement in each LED display device 100.
  • the luminance measurement sequence of each second LED 3A becomes complicated.
  • the second LED 3A in the second embodiment is driven by one luminance mode (one drive current value) and a duty ratio in one LED display device 100.
  • the LED display control device 300 collects the luminance measurement results of the second LED 3A driven by the duty ratios different from each other from the plurality of LED display devices 100, and calculates the plurality of luminance reduction characteristics. Therefore, the luminance measurement sequence in one LED display device 100 can be simplified.
  • the first drive condition in the LED display system includes a condition regarding a drive current for driving a plurality of first LEDs 1A.
  • Each of the plurality of predetermined second drive conditions includes a condition regarding a drive current for driving at least one second LED 3A.
  • FIG. 10 is a diagram showing an example of a processing circuit 400 included in the LED display control device 300.
  • Each function of the luminance reduction characteristic calculation unit 21 and the luminance correction unit 22 is realized by the processing circuit 400. That is, the processing circuit 400 has a luminance reduction characteristic calculation unit 21 and a luminance correction unit 22.
  • the processing circuit 400 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable). GateArray), or a circuit that combines these.
  • Each function of the luminance reduction characteristic calculation unit 21 and the luminance correction unit 22 may be realized individually by a plurality of processing circuits, or may be realized collectively by one processing circuit.
  • FIG. 11 is a diagram showing another example of the processing circuit included in the LED display control device 300.
  • the processing circuit includes a processor 500 and a memory 600.
  • each function of the luminance reduction characteristic calculation unit 21 and the luminance correction unit 22 is realized.
  • each function is realized by executing software or firmware described as a program by the processor 500. That is, the LED display control device 300 has a memory 600 for storing a program and a processor 500 for executing the program.
  • the LED display control device 300 acquires the measurement result of the brightness of each second LED 3A driven from each LED display device 100 under different second drive conditions, and the cumulative lighting of each second LED 3A is based on the measurement result of the brightness.
  • the brightness reduction characteristic with respect to time is calculated for each second drive condition and for each BIN rank, and is included in the video signal based on the brightness reduction characteristic of one of the calculated brightness reduction characteristics and the cumulative lighting time of each first LED 1A.
  • a function is described in which the brightness of an image is corrected for each first LED 1A, and the image signal after the brightness correction is distributed to each LED display device 100 to control the display of the image after the brightness correction on one screen.
  • the program causes the computer to execute the procedure or method of the luminance reduction characteristic calculation unit 21 and the luminance correction unit 22.
  • the processor 500 is, for example, a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), or the like.
  • the memory 600 is, for example, non-volatile or volatile such as RAM (RandomAccessMemory), ROM (ReadOnlyMemory), flash memory, EPROM (ErasableProgrammableReadOnlyMemory), EPROM (ElectricallyErasableProgrammableReadOnlyMemory). It is a semiconductor memory.
  • the memory 600 may be any storage medium used in the future, such as a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD.
  • Some of the functions of the luminance reduction characteristic calculation unit 21 and the luminance correction unit 22 described above may be realized by dedicated hardware, and some of them may be realized by software or firmware. In this way, the processing circuit realizes each of the above-mentioned functions by hardware, software, firmware, or a combination thereof.
  • each embodiment can be freely combined, and each embodiment can be appropriately modified or omitted.

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Abstract

Le but de la présente invention est de fournir un système d'affichage à DEL capable de réduire la variation de luminance et la variation de chromaticité dans une unité d'affichage. Le système d'affichage à DEL selon la présente invention comprend une pluralité de dispositifs d'affichage à DEL et un dispositif de commande d'affichage à DEL. Chaque dispositif d'affichage à DEL comprend une première unité d'affichage comportant une pluralité de premières DEL correspondant respectivement à une pluralité de rangs BIN et une seconde unité d'affichage comportant une pluralité de secondes DEL correspondant respectivement aux mêmes rangs BIN que les premières DEL. Le dispositif de commande d'affichage à DEL comprend : une unité de calcul de caractéristique de réduction de luminance qui acquiert un résultat de mesure de la luminance de chaque seconde DEL attaquée selon une seconde condition d'attaque qui est différente de celle de chaque dispositif d'affichage à DEL, et qui calcule, sur la base du résultat de mesure de la luminance, des caractéristiques de réduction de luminance pour un temps d'éclairage cumulé de chaque seconde DEL pour chaque seconde condition d'attaque et pour chaque rang BIN ; et une unité de correction de luminance qui corrige la luminance d'une image pour chaque première DEL sur la base d'une caractéristique de réduction de luminance parmi les caractéristiques de réduction de luminance et le temps d'éclairage cumulé de chaque première DEL.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115081569A (zh) * 2022-07-20 2022-09-20 合肥龙旗智能科技有限公司 阵列led贴片管理方法、阵列led控制系统及方法

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04128875A (ja) * 1990-09-20 1992-04-30 Matsushita Electric Ind Co Ltd Ｌｅｄ表示装置
JP2003022052A (ja) * 2001-07-10 2003-01-24 Sony Corp 発光素子の駆動回路及び画像表示装置
US20080122832A1 (en) * 2006-11-29 2008-05-29 Hong Kong Applied Science and Technology Research Institute Company Limited Image display apparatus
US20110266976A1 (en) * 2010-04-30 2011-11-03 Wanfeng Zhang System and Method of Tuning Current for LEDs
JP2017032889A (ja) * 2015-08-05 2017-02-09 三菱電機株式会社 Ｌｅｄ表示装置
JP2017032890A (ja) * 2015-08-05 2017-02-09 三菱電機株式会社 Ｌｅｄ表示装置
WO2017061195A1 (fr) * 2015-10-05 2017-04-13 三菱電機株式会社 Dispositif d'affichage à diode électroluminescente
WO2018179196A1 (fr) * 2017-03-30 2018-10-04 三菱電機株式会社 Dispositif d'affichage à diodes électroluminescentes et procédé de correction de luminance associé
WO2019229971A1 (fr) * 2018-06-01 2019-12-05 三菱電機株式会社 Dispositif d'affichage

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04128875A (ja) * 1990-09-20 1992-04-30 Matsushita Electric Ind Co Ltd Ｌｅｄ表示装置
JP2003022052A (ja) * 2001-07-10 2003-01-24 Sony Corp 発光素子の駆動回路及び画像表示装置
US20080122832A1 (en) * 2006-11-29 2008-05-29 Hong Kong Applied Science and Technology Research Institute Company Limited Image display apparatus
US20110266976A1 (en) * 2010-04-30 2011-11-03 Wanfeng Zhang System and Method of Tuning Current for LEDs
JP2017032889A (ja) * 2015-08-05 2017-02-09 三菱電機株式会社 Ｌｅｄ表示装置
JP2017032890A (ja) * 2015-08-05 2017-02-09 三菱電機株式会社 Ｌｅｄ表示装置
WO2017061195A1 (fr) * 2015-10-05 2017-04-13 三菱電機株式会社 Dispositif d'affichage à diode électroluminescente
WO2018179196A1 (fr) * 2017-03-30 2018-10-04 三菱電機株式会社 Dispositif d'affichage à diodes électroluminescentes et procédé de correction de luminance associé
WO2019229971A1 (fr) * 2018-06-01 2019-12-05 三菱電機株式会社 Dispositif d'affichage

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115081569A (zh) * 2022-07-20 2022-09-20 合肥龙旗智能科技有限公司 阵列led贴片管理方法、阵列led控制系统及方法

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