LED display device and method for controlling LED display device

Abstract

An LED display device in which a plurality of LED modules are aligned, the LED module comprising: a signal processing unit (1c11) that causes a display unit to display a video based on a video signal supplied from an external device; an AC-DC power supply unit (1d11) that converts AC power supplied from a power supply path, which is connected to a power input port (23t-1) and a power output port (23t-2), into DC power and supplies the DC power to the signal processing unit (1c11); a first switch that is provided in the power supply path and switches whether or not the AC power input to the power input port (23t-1) is supplied to the power output port (23t-2); and a switch control unit (1c11d) that supplies, to the first switch, a first switching control signal for switching the first switch so as to supply the AC power input to the power input port (23t-1) to the power output port (23t-2), in response to the signal processing unit (1c11) detecting an external video signal.

Description

LED display device and control method for LED display device

[0001] The present invention relates to an LED display device and a method for controlling an LED display device.

[0002] There is an LED display system that has an LED display in which multiple LED (Light Emitting Diode) modules are arranged adjacent to each other and displays an image according to a video signal supplied from a video source device. Such an LED display system is connected to a distribution board, and power is supplied from the distribution board to the LED display system. The power supplied from the distribution board is supplied to each LED module of the LED display.

[0003] In such an LED display system, it is desirable to reduce power consumption. In order to reduce power consumption, when cutting off the power supply to the LED display, it is conceivable to operate a distribution board to cut off the power supply to the LED display.

[0004] JP 2011-008303 A

[0005] In such LED display systems, the distribution board may be installed in a location away from the LED displays, the control room, etc. In this case, a system for remotely turning the power on and off on the distribution board for each LED display system must be introduced, or, for distribution boards that cannot be remotely operated, an operator must go to the location where the distribution board is installed and operate the distribution board manually.

[0006] Furthermore, when powering on an LED display, if power is supplied to multiple LED modules simultaneously, depending on the size of the LED display, the inrush current can become enormous, causing the breaker in the distribution board to trip and cut off the power supply. This can lead to a situation where the LED display cannot be started until the distribution board is restored. Furthermore, when the LED display is not displaying video, even if the video signal supply is cut off by, for example, stopping the operation of the video source device, power is still supplied to the LED module. In this case, even if the LED panel is turned off, power is consumed because the signal processing unit and other components in the LED module are still operating.

[0007] Therefore, the present invention provides an LED display device and a method for controlling an LED display device that can easily manage power consumption so as to reduce the power consumption of the LED display while preventing an inrush current from occurring.

[0008] One aspect of the present invention is an LED display device in which a plurality of LED modules are arranged, the LED modules comprising: a display unit having a plurality of LED elements mounted thereon; a signal processing unit that causes the display unit to display an image based on an image signal supplied from an external device; a power input port to which AC power is input from the outside; a power output port that can supply the AC power input to the power input port to a subsequent LED module; and an AC / DC power supply unit that converts the AC power supplied from a power supply path connecting the power input port and the power output port into DC power and supplies the DC power to at least the signal processing unit. The LED display device has: a first switch provided in the power supply path, which switches whether or not AC power input to the power input port is supplied to the power output port; a video signal input port to which the video signal is input; a video output port that can supply the video signal input to the video signal input port to the downstream LED module; and a switch control unit that supplies a first switching control signal to the first switch, which switches the first switch so that the AC power input to the power input port is supplied to the power output port in response to the signal processing unit detecting the video signal.

[0009] Another aspect of the present invention is an LED display device in which a plurality of LED modules are arranged, the LED modules including a display unit having a plurality of LED elements mounted thereon, a signal processing unit that causes the display unit to display an image based on an image signal supplied from a preceding LED module, a power input port to which AC power is input from the preceding LED module, a power output port that can supply the AC power input to the power input port to a succeeding LED module, an AC / DC power supply unit that converts the AC power supplied from a power supply path connecting the power input port and the power output port into DC power and supplies the DC power to at least the signal processing unit, and a power supply circuit that supplies the DC power from the power supply path to the AC / DC power supply unit. a second switch that switches whether to supply AC power to the subsequent LED module, a video signal input port to which the video signal is input, and a video output port that can supply the video signal input to the video signal input port to the subsequent LED module, wherein the second switch is switched to supply AC power from the power supply path to the AC / DC power supply unit in response to a second switching control signal input from the previous LED module, and the LED module further has a switch control unit that supplies a third switching control signal to the subsequent LED module in response to the signal processing unit detecting the video signal.

[0010] Another aspect of the present invention is a control method for an LED display device in which a plurality of LED modules are arranged, each LED module having a display unit equipped with a plurality of LED elements, a signal processing unit that causes the display unit to display an image based on a video signal supplied from an external device, and a first switch that switches whether or not AC power supplied from the outside is supplied to an LED module connected in a subsequent stage, wherein the AC power supplied from the outside is converted into DC power and supplied to the signal processing unit, and when the DC power is supplied, the signal processing unit supplies the video signal input from the outside to the LED module in the subsequent stage, and in response to detecting the video signal, the signal processing unit supplies a first switching control signal to the first switch that switches the first switch so that the AC power is supplied to the LED module in the subsequent stage.

[0011] Another aspect of the present invention is a control method for an LED display device in which a plurality of LED modules are arranged, each LED module having a display unit equipped with a plurality of LED elements, a signal processing unit that causes an image based on a video signal supplied from a preceding LED module to be displayed on the display unit, and a second switch that switches whether or not the AC power supplied from the preceding LED module is supplied to an AC / DC power supply unit, wherein the second switch switches to supply the AC power to the AC / DC power supply unit in response to a switching control signal being supplied from the preceding LED module to the second switch, the AC power is converted by the AC / DC power supply unit into DC power and supplied to the signal processing unit, the signal processing unit supplies the externally input video signal to the subsequent LED module, and the signal processing unit detects the video signal and supplies a third switching control signal to the subsequent LED module for switching the second switch of the subsequent LED module.

[0012] According to the present invention, the power consumption of an LED display can be reduced while easily managing the power consumption so as to prevent an inrush current from occurring.

[0013] FIG. 1 is a schematic configuration diagram of an LED display system S according to the present embodiment. FIG. 1 is a schematic functional block diagram illustrating the configuration of an LED module 1-11. FIG. 2 is a diagram illustrating an LED display system Sa in which three LED modules 1-11 are connected in a column direction (vertical direction). FIG. 3 is a diagram illustrating a case in which the supply of a video signal is stopped in the LED display system Sa. FIG. 4 is a schematic functional block diagram illustrating the configuration of an LED module 1-111 in a second embodiment. FIG. 5 is a diagram illustrating an LED display system Sb in which three LED modules 1-21 are connected in a column direction (vertical direction). FIG. 6 is a diagram illustrating a case in which the supply of a video signal is stopped in the LED display system Sb. FIG. 7 is a schematic functional block diagram illustrating the configuration of a first type LED module 1-112. FIG. 8 is a schematic functional block diagram illustrating the configuration of a second type LED module 1-113. FIG. 9 is a diagram illustrating the configuration of an LED display system Sc. FIG. 10 is a diagram illustrating the configuration of an LED display system Sd.

[0014] An LED display system according to one embodiment of the present invention will be described below with reference to the drawings. First Embodiment (LED Display System) Fig. 1 is a schematic diagram of an LED display system S according to this embodiment. The LED display system S includes an LED display LD, a video source device VS, an LED controller LC, a distribution board DB, a signal cable SC, and a power cable PC.

[0015] (LED Display LD) The LED display LD includes a plurality of LED modules 1. The LED modules 1 are arranged adjacent to each other so as to be aligned vertically and horizontally. In this diagram, the plurality of LED modules 1 are arranged in a matrix of n (n is a natural number of 2 or greater) vertically and m (m is a natural number of 2 or greater) horizontally, for a total of n x m LED modules 1. The LED display LD displays an image based on a video signal using the entire display area of ​​the plurality of LED modules 1 thus aligned.

[0016] The LED modules 1 are cascade-connected, and a video signal and power are respectively supplied to the LED module 1 connected in the next stage. For example, the LED module 1-11 is arranged in the bottom stage (first stage) of the leftmost column (first column), and the LED modules 1-21, ..., 1-n1 are arranged in order above it and electrically connected in series. Furthermore, the LED modules 1-12, ..., 1-1m are arranged in order to the right of the LED module 1-11 and electrically connected in series.

[0017] Here, the LED modules 1 in each row are connected in series to adjacent LED modules 1 in the vertical direction via a communication cable (e.g., a LAN (Local Area Network) cable). Furthermore, the first LED module 1 in each row is connected to an LED controller LC via a communication cable (e.g., a LAN cable). More specifically, the LED module 1-11 is electrically connected to the LED controller LC via a signal cable SC, and the LED module 1-12 is electrically connected to the LED controller LC via the signal cable SC. Thus, a video signal output from the LED controller LC is supplied to each first LED module 1 in each row. The first LED module 1 in each row outputs various signals to the LED module 1 connected to the next row via the communication cable. Thus, video signals are transmitted sequentially from the first LED module 1 in each row to the last LED module 1 in each row.

[0018] Furthermore, of the LED modules 1 in the lowest row of each column of LED modules 1, the two adjacent LED modules 10 are connected to a distribution board DB and are supplied with AC power. For example, LED module 1-11, LED module 1-12, ..., LED module 1-1m are each connected to the distribution board DB via a power cable PC. As a result, AC power is supplied from the power cable PC to the module group in the first column including LED module 1-11, the module group in the second column including LED module 1-12, and the module group in the m-th column including LED module 1-1m.

[0019] By connecting multiple LED modules 1 in this manner, for example, if the display resolution of a single LED module 1 is 192 x 108, arranging 10 LED modules 1 vertically and 10 horizontally can create an LED display LD of 1920 x 1080 (full HD screen).

[0020] The video source device VS is connected to the LED controller LC via a communication line and is a supply source that outputs a video signal to the LED controller LC. The specifications of the communication line connecting the video source device VS and the LED controller LC may be compatible with any of the standards such as DVI I / F or HDMI (registered trademark) I / F. The video source device VS may be, for example, a computer.

[0021] The video source device VS receives the video signal output, divides the video signal into sections of the cascaded LED modules 1, converts the video signal into a signal format that can be received by the LED modules, and then outputs the signal via the signal cable SC to the LED modules 1. If no video signal is supplied from the video source device VS, it is possible not to output a signal to the LED modules.

[0022] The LED controller LC supplies a video signal to the LED module 1. The LED controller LC is an example of an external device. The LED controller LC outputs a video signal output from a video source device VS to the LED display LD. For example, the LED controller LC divides the video signal output from the video source device VS in accordance with the arrangement of the LED modules 1, converts it into a video signal in a format that can be received by the LED module 1, and outputs it to the LED module 1.

[0023] The distribution board 2 has a safety breaker, a ground fault circuit interrupter, etc., and supplies AC power required for the operation of each LED module 1 of the LED display LD via the power cable PC. The supplied power is, for example, AC (Alternating Current) power.

[0024] The signal cable SC supplies a video signal supplied from the output port of the LED controller LC to the first LED module 1 in each row. The LED module 1 outputs the video signal supplied from the video source device VS or the previous LED module 1 to the next cascaded LED module 1. Thereafter, signals are supplied to the cascaded LED modules 1 in the same manner.

[0025] The power cable PC supplies AC power output from the distribution board DB to the first LED module 1 (1-11, 1-12, . . . , 1-1m) in each row.

[0026] AC power input from the power input terminal is output to the LED module connected in the next stage, and AC power is similarly supplied to the subsequent cascade-connected LED modules.

[0027] 2 is a schematic functional block diagram illustrating the configuration of the LED module 1-11. Here, of the multiple LED modules 1, the LED module 1-11 shown in FIG. 1 will be described, but the other LED modules 1 (1-21, 1-n1, 1-12, 1-22, ..., 1-nm, etc.) also have similar functions. The LED module 1-11 is mounted on the electrical board 1EB, including a video signal input terminal 21t-1, a video signal output terminal 21t-2, a power input terminal 23t-1, a power output terminal 23t-2, an LED display unit 1b11, a signal processing unit 1c11, an AC / DC power supply unit 1d11, a switch 1sa11, and a switch 1sb11.

[0028] The video signal input terminal 21t-1 is electrically connected to the LED controller LC via a signal cable SC, and receives a video signal supplied from the LED controller LC. The video signal input terminal 21t-1 is connected to an input terminal of the signal processing unit 1c11 via a signal line. The video signal input terminal may be a video signal input port.

[0029] The video signal output terminal 21t-2 is electrically connected to the output terminal of the video processing unit 1c11a via a signal line. The video signal output terminal 21t-2 can supply the video signal input to the video signal input terminal 21t-1 to the LED module in the subsequent stage. The video signal output terminal 21t-2 is connected to the video signal input terminal 21t-3 of the LED module 1-21 that is attached adjacent to the LED module 1-11 in the next stage. The signal output terminal may be a video output port.

[0030] The power input terminal 23t-1 receives AC power from the outside. The outside may be, for example, a distribution board DB or the power output terminal of a preceding LED module. More specifically, the power input terminal 23t-1 of the LED module connected in the first stage is connected to the distribution board DB, and the LED modules connected in the second stage and beyond are connected to the power output terminal of the preceding LED module. The power input terminal may be a power input port. The power input terminal 23t-1 is electrically connected to the distribution board DB via a power cable PC and inputs power supplied from the distribution board DB. The power input terminal 23t-1 is electrically connected to the AC / DC power supply unit 1d11 and a first terminal of the switch 1sa11 via a power line.

[0031] The power output terminal 23t-2 can supply AC power input to the power input terminal 23t-1 to the LED module in the subsequent stage. The power output terminal may be a power output port. For example, the power output terminal 23t-2 is electrically connected to the second terminal of the switch 1sa11 via a power line. The power output terminal 23t-2 is connected to the power input terminal 23t-3 of the LED module 1-21 that is attached adjacent to the LED module 1-11 in the subsequent stage. When the switch 1sa11 is in the on state, AC power is supplied from the power output terminal 23t-2 to the LED module 1 in the subsequent stage (e.g., the LED module 1-21). When the switch 1sa11 is in the off state, AC power is not supplied from the power output terminal 23t-2 to the LED module 1 in the subsequent stage (e.g., the LED module 1-21).

[0032] In this way, the LED module 1 inputs the video signal output from the LED controller LC or the signal output terminal of the previous cascaded LED module 1 through its video signal input terminal, and the input video signal is input to the video processing unit of the signal processing unit and output to the signal output terminal of the next cascaded LED module.

[0033] AC / DC power supply unit 1d11 converts AC power supplied from a power supply path connecting power input terminal 23t-1 and power output terminal 23t-2 into DC power and supplies the DC power to at least signal processing unit 1c11. For example, AC / DC power supply unit 1d11 converts AC power supplied from power input terminal 23t-1 into DC power and supplies the DC power to signal processing unit 1c11 and the first terminal of switch 1sb11. When switch 1sb11 is on, the DC power output from AC / DC power supply unit 1d11 is supplied to LED display unit 1b11, and when switch 1sb11 is off, the DC power is not supplied to LED display unit 1b11. The supply of DC power from AC / DC power supply unit 1d11 to signal processing unit 1c11 enables signal processing unit 1c11 to be driven. Furthermore, when direct current power is supplied from AC / DC power supply unit 1d11 to LED display unit 1b11, LED display unit 1b11 can be driven.

[0034] Signal processing unit 1c11 displays an image based on a video signal supplied from an external device on the display unit. The external device may be, for example, an LED controller LC or an LED module connected in a previous stage. More specifically, the LED module connected in the first stage is connected to LED controller LC, and the LED modules connected in the second stage or later are connected to the LED module in the previous stage. Signal processing unit 1c11 includes video processing unit 1c11a, LED drive signal generation unit 1c11b, video detection unit 1c11c, switch control unit 1c11d, and amplifier element 1c11e. Signal processing unit 1c11 cuts out (extracts) a portion of the image to be displayed by LED module 1-11 itself from the video signal input from video signal input terminal 21t-1, generates an LED drive signal corresponding to the cut-out portion, and supplies it to LED display unit 1b11.

[0035] Video detector 1c11c determines (detects) whether or not a video signal is being input from video signal input terminal 21t-1 (presence or absence of a video signal), and outputs the determination result to switch controller 1c11d.

[0036] In response to signal processing unit 1c11 detecting a video signal, switch control unit 1c11d supplies switch 1sa11 with a first switching control signal that causes switch 1sa11 to switch so that AC power input to power input terminal 23t-1 is supplied to power output terminal 23t-2. In addition, in response to signal processing unit 1c11 not detecting a video signal, switch control unit 1c11d supplies switch 1sa11 with a first switching control signal that causes switch 1sa11 to switch so that AC power input to power input terminal 23t-1 is not supplied to power output terminal 23t-2. For example, based on the determination result of video detection unit 1c11c, if the presence of a video signal is detected, switch control unit 1c11d sets switches 1sa11 and 1sb11 to ON, and if no video signal is detected, sets switches 1sa11 and 1sb11 to OFF. In addition, the switch control unit 1c11d may supply a signal different from the first switching control signal to the switch 1sa11, if it is possible to prevent the AC power input to the power input terminal 23t-1 from being supplied to the power output terminal 23t-2.

[0037] When the switch 1sa11 is ON, AC power is supplied to the next-stage LED module 1, and when it is OFF, the supply of AC power is stopped. When the switch 1sb11 is ON, DC power is supplied to the LED display unit 1b11 in the LED module 1-11, and when it is OFF, the supply of DC power to the LED display unit 1b11 is stopped.

[0038] The switch 1sa11 is provided in the power supply path and switches whether or not AC power input to the power input terminal 23t-1 is supplied to the power output terminal 23t-2. The switch 1sa11 is an example of a first switch.

[0039] Amplification element 1c11e supplies the video signal input from video signal input terminal 21t-1 to video signal output terminal 21t-2. When the video signal is supplied from amplification element 1c11e to video signal output terminal 21t-2, the video signal is supplied to the next-stage LED module 1 in the same column. Here, if a video signal is not supplied from video signal input terminal 21t-1, amplification element 1c11e does not supply a video signal to video signal output terminal 21t-2.

[0040] The LED display unit 1b11 is configured to include one or more LED panels LDP. The LED panel LDP has multiple sets of LED light-emitting units arranged horizontally (horizontally) and vertically (longitudinal). One LED light-emitting unit corresponds to one pixel. One LED light-emitting unit includes an LED element that emits red, an LED element that emits green, and an LED element that emits blue. The LED display unit 1b11 displays an image corresponding to a video signal based on a drive signal transmitted from the LED drive signal generation unit.

[0041] 3 is a diagram showing an LED display system Sa in which three LED modules 1-11 shown in FIG. 2 are connected in a column direction (vertical direction). In this diagram, the LED modules are LED module 1-11, LED module 1-21, and LED module 1-31, which are connected in a row. Since the LED module 1-21 and the LED module 1-31 have the same functions as the LED module 1-11, the corresponding components are given the same names but different reference numerals, and the following description will mainly focus on the different functions.

[0042] When AC power is output from distribution board DB, the power is supplied to LED module 1-11 via power input terminal 23t-1. As a result, AC power is supplied to AC / DC power supply unit 1d11 in LED module 1-11. When AC / DC power supply unit 1d11 is supplied with AC power, it converts the AC power to DC power and supplies it to signal processing unit 1c11. Here, AC / DC power supply unit 1d11 also outputs DC power to switch 1sb11, but when a switch control signal is not output from switch control unit 1c11d, switch 1sb11 is OFF and no power is supplied to LED display unit 1b11.

[0043] The video source device VS outputs a video signal to the LED controller LC. The LED controller LC supplies the video signal supplied from the video source device VS to the LED module 1 provided in the first stage of each column. For example, the LED controller LC supplies the video signal to the LED module 1-11.

[0044] Here, if a video signal is not supplied from LED controller LC to LED module 1-11, video detector 1c11c in LED module 1-11 does not detect a video signal, and therefore video detector 1c11c supplies switch controller 1c11d with a detection result indicating that a video signal is not detected. In this case, switch controller 1c11d supplies switch 1sa11 with a switch control signal that switches switch 1sa11 OFF, so switch 1sa11 is OFF, and therefore AC power is not supplied to cascaded LED module 1-21, LED module 1-31, and any subsequent LED modules.

[0045] Next, when a video signal is supplied from LED controller LC to LED module 1-11, the video signal is supplied to signal processing unit 1c11 within LED module 1-11. Video detection unit 1c11c of signal processing unit 1c11 detects this video signal and supplies a detection result indicating that the video signal has been detected to switch control unit 1c11d. In response to receiving the detection result indicating that the video signal has been detected, switch control unit 1c11d outputs a switch control signal to switch 1sb11 to switch ON, and also outputs a switch control signal to switch 1sa11 to switch ON. As a result, switch 1sb11 and switch 1da11 are both turned ON. When switch 1sb11 is turned ON, DC power is supplied from AC / DC power supply unit 1d11 to LED display unit 1b11. When the switch 1sa11 is turned on, AC power input via the power input terminal 23t-1 is supplied to the LED module 1-21 via the power input terminal 23t-3 connected to the power output terminal 23t-2.

[0046] Meanwhile, when a video signal is supplied from LED controller LC to LED module 1-11 and then supplied to signal processing unit 1c11, video processing unit 1c11a generates an LED drive signal from the video signal and supplies it to LED display unit 1b11. LED display unit 1b11 receives DC power from AC / DC power supply unit 1d11 and receives an LED drive signal corresponding to the video signal from video processing unit 1c11a, which drives each LED light-emitting unit in accordance with the LED drive signal. As a result, an image based on the video signal is displayed on LED display unit 1b11. Furthermore, when a video signal is supplied from LED controller LC to signal processing unit 1c11 of LED module 1-11, signal processing unit 1c11 supplies the video signal to video signal output terminal 21t-2 via amplifier element 1c11e. The video signal supplied to video signal output terminal 21t-2 is supplied to signal processing unit 1c21 via video signal input terminal 21t-3 of LED module 1-21.

[0047] In this way, in response to the video signal being supplied to the LED module 1-11, an image corresponding to the video signal is displayed on the LED display section 1b11, and AC power and the video signal are supplied to the LED module 1-21.

[0048] In addition, if a video signal is supplied from the LED controller LC to the LED module 1-11 before AC power is supplied from the distribution board DB to the LED module 1-11, power is not supplied to the signal processing unit 1c11 from the AC / DC power supply unit 1d11, so no switch control signal is supplied from the signal processing unit 1c11 to the switch 1sb11, and therefore the LED display unit 1b11 is not driven and no video is displayed.

[0049] When AC power is supplied to LED module 1-21, AC / DC power supply unit 1d21 converts the AC power to DC power and supplies it to signal processing unit 1c21. Here, AC / DC power supply unit 1d11 also outputs DC power to switch 1sb21, but when a switch control signal is not output from switch control unit 1c21d, switch 1sb21 is OFF and no power is supplied to LED display unit 1b11.

[0050] Next, when a video signal is supplied from video signal output terminal 21t-2 to video signal input terminal 21t-3 of LED module 1-11, the video signal is supplied to signal processing unit 1c21 in LED module 1-21. Video detection unit 1c21c of signal processing unit 1c21 detects this video signal and supplies a detection result indicating that the video signal has been detected to switch control unit 1c21d. In response to receiving the detection result indicating that the video signal has been detected, switch control unit 1c11d outputs a switch control signal to switch 1sb21 to switch ON, and also outputs a switch control signal to switch 1sa11 to switch ON. As a result, switch 1sb21 and switch 1da21 are both turned ON. When switch 1sb21 is turned ON, DC power is supplied from AC / DC power supply unit 1d21 to LED display unit 1b21. When the switch 1sa21 is turned on, AC power input via the power input terminal 23t-3 is supplied to the LED module 1-31 via the power input terminal 23t-5 connected to the power output terminal 23t-4.

[0051] Meanwhile, when a video signal is supplied from LED module 1-11 to LED module 1-21 and then supplied to signal processing unit 1c21, video processing unit 1c21a extracts from the video signal the portion of the video to be displayed on its own LED module 1-21, performs video processing on the extracted portion of the video, and outputs it to LED drive signal generation unit 1c21b. LED drive signal generation unit 1c21b generates an LED drive signal based on the switch control signal input from video processing unit 1c21a and outputs it to LED display unit 1b21. LED display unit 1b21 is supplied with DC power from AC / DC power supply unit 1d21, and when an LED drive signal corresponding to the video signal is supplied from LED drive signal generation unit 1c21b, it drives each LED light-emitting element in accordance with the LED drive signal. As a result, an image based on the video signal is displayed on LED display unit 1b21. Furthermore, when a video signal is supplied from LED module 1-11 to signal processing unit 1c21 of LED module 1-21, signal processing unit 1c21 supplies the video signal to video signal output terminal 21t-4 via amplifier element 1c21e. The video signal supplied to video signal output terminal 21t-4 is supplied to signal processing unit 1c31 via video signal input terminal 21t-5 of LED module 1-31.

[0052] In this way, when AC power is supplied to the LED module 1-21, the operation of the LED module 1-21 is started, the video detection unit 1c21c in the LED module 1-21 detects the signal, and the switch control unit 1c21d turns on the switches 1sb21 and 1sa21. Therefore, the LED module 1-21 becomes capable of displaying an image corresponding to the video signal, and supplies the video signal and AC power to the LED module 1-31.

[0053] 3, switch 1sa31 is OFF, but when AC power is supplied from LED module 1-21 to LED module 1-31, switch 1sa31 is turned ON. Then, in response to the supply of a video signal from LED module 1-21, signal processing unit 1c31 turns on switches 1sb31 and 1sa31. As a result, AC power is supplied from LED module 1-31 to the LED module in the next stage after LED module 1-31, and an image corresponding to the video signal is displayed on LED display unit 1b31.

[0054] If multiple LED modules are connected after the next stage of LED module 1-31, they are similarly powered on sequentially with a time lag, and an image corresponding to the video signal is displayed. Furthermore, in the above example, in response to the video signal being supplied to signal processing unit 1c11, switch control unit 1c11d outputs a switch control signal to switch 1sa11 to turn ON the switch 1sa11, causing power to be supplied to LED module 1-21, and then signal processing unit 1c11 supplies the video signal to LED module 1-21. Here, after signal processing unit 1c11 supplies the video signal to LED module 1-21, switch control unit 1c11d may output a switch control signal to switch 1sa11 to turn ON the switch 1sa11, causing power to be supplied to LED module 1-21. Then, switch control unit 1c11d switches switch 1sb11 ON, causing DC power to be supplied from AC / DC power supply unit 1d11 to LED display unit 1b11. Then, LED drive signal generation unit 1c11b may generate an LED drive signal from the video signal and supply it to LED display unit 1b11 to display an image.

[0055] In this way, the signal processing unit 1c11 outputs a video signal to the subsequent stage, and then the switch 1sa11 is turned ON to supply power to the subsequent LED module 1-21. This process can also be performed in each LED module (1-21, 1-31, ...) connected to the subsequent stage. As a result, the LED module is supplied with power from the preceding LED module while the video signal is being input, so that the switches (1sa21, 1sa31, ...) and switches (1sb21, 1sb31, ...) can be turned ON quickly after power is supplied. Here, the LED display units (1b11, 1b21, 1b31, ...) of each LED module may be timed so that, after the video signal is supplied from the LED controller LC to the LED display LD, images corresponding to the video signal are simultaneously displayed.

[0056] 4 is a diagram showing a case where the supply of a video signal is stopped in the LED display system Sa shown in FIG. 3. When AC power is supplied from the distribution board DB, power is supplied to the LED module 1-11. In other words, AC power is supplied to the AC / DC power supply unit 1d11 in the LED module 1-11. When a video signal is output from the LED controller LC, the switches (1sa11, 1sb11, 1sa21, 1sb21, 1sa31, 1sb31) in all cascaded LED modules (1-11, 1-21, 1-31) are in the ON state.

[0057] When the video signal from the LED controller LC is stopped, the video detector 1c11c is put into a state where it does not detect a video signal, and the switches 1sa11 and 1sb11 in the LED module 1-11 are switched to the OFF state. Then, because the switch 1sa11 is switched to the OFF state, the supply of AC power to the subsequent LED modules 1-21 and 1-31 and the subsequent LED modules is stopped.

[0058] Then, as the video signal from the LED controller LC is stopped, the switch 1sb11 of the LED module 1-11 is also switched to the OFF state, and therefore, no DC power is supplied to the LED display unit 1b11 of the LED module 1-11, and therefore no power is consumed by the LED display unit 1b11. Note that, from the time when the input of the video signal to the signal processing unit 1c11 is stopped until the switch 1sb11 is switched OFF, there is a period during which power is supplied to the LED display unit 1b11. During this period, the LED display unit 1b11 displays an image (black image) that turns the entire LED panel LDP black. Therefore, the only part that is operating (consuming power) is the signal processing unit 1c11 in the LED module 1-11. That is, even if AC power is supplied from the distribution board DB, the AC / DC power supply unit 1d11 of LED module 1-11 converts the AC power to DC power and supplies the DC power to the signal processing unit 1c11, but power is not supplied from LED module 1-11 to the next-stage LED modules (1-21, etc.). Therefore, the part that consumes power is the signal processing unit 1c11 in LED module 1-11, and power is not consumed by the LED display unit 1b11, nor is power consumed by LED modules 1-21 and later.

[0059] Second Embodiment Fig. 5 is a schematic functional block diagram illustrating the configuration of an LED module 1-111 according to a second embodiment. The LED module 1-111 has the same functions as the corresponding components of the LED module 1-11 according to the first embodiment, and the same reference numerals are used to designate the same components, and descriptions thereof will be omitted. Different functions are designated by different reference numerals and will be described. The LED module 1-111 has additional terminals on the electrical board 1EB1, namely, a switch control input terminal 22t-1 and a switch control output terminal 22t-2. The switch control input terminal 22t-1 inputs a signal supplied from the outside. The switch control output terminal 22t-2 supplies a signal to the outside.

[0060] Signal processing unit 1c111 operates in response to the input of DC power from AC / DC power supply unit 1d11, and supplies the video signal input to video signal input terminal 21t-1 to a subsequent LED module (e.g., LED module 1-211) from video signal output terminal 21t-2. When DC power is not input from AC / DC power supply unit 1d11, signal processing unit 1c111 does not supply the video signal to the subsequent LED module (e.g., LED module 1-211).

[0061] In response to signal processing unit 1c111 detecting a video signal, switch control unit 1c11d1 supplies a switch control signal (e.g., a third switching control signal) to the subsequent LED module for switching switch 1sb111 of the subsequent LED module. In response to signal processing unit 1c111 not detecting a video signal, switch control unit 1c11d1 supplies a switch control signal (a third switching control signal) to the subsequent LED module for switching a second switch (e.g., switch 1sb211 of LED module 1-211) of the subsequent LED module so that power is not supplied from the power supply path to AC / DC power supply unit 1d11. For example, switch control unit 1c11d1 controls switching switch 1sb11 ON or OFF based on the detection result of whether video detection unit 1c11c has detected a video signal, and outputs a switch control signal from switch control output terminal 22t-2 to the cascaded subsequent LED module 1-211.

[0062] When switch control unit 1c11d1 supplies a switch control signal to switch 1sb11, switch control unit 1c11d1 operates in response to input of DC power from AC / DC power supply unit 1d11, thereby supplying to switch 1sb11 a switch control signal (fourth switching control signal) that switches switch 1sb11 (fifth switch) so that DC power is supplied from AC / DC power supply unit 1d11 to LED display unit 1b111. When switch control unit 1c11d1 supplies a switch control signal to switch 1sb11, switch control unit 1c11d1 supplies to switch 1sb11 a switch control signal (fourth switching control signal) that switches so that DC power is not supplied from AC / DC power supply unit 1d11 to LED display unit 1b111 in response to video detection unit 1c11c of signal processing unit 1c111 not detecting a video signal. Switch control unit 1c11d1 switches switch 1sb11 ON based on a detection result indicating that a video signal has been detected by video detection unit 1c11c, and switches switch 1sb11 OFF based on a detection result indicating that a video signal has not been detected by video detection unit 1c11c.

[0063] Switch 1sb111 switches whether or not AC power is supplied from the power supply path to AC / DC power supply unit 1d11. A first terminal of switch 1sb111 is connected to the power supply path between power input terminal 23t-1 and power output terminal 23t-2. A second terminal of switch 1sb111 is connected to the power input terminal of AC / DC power supply unit 1d11. For example, switch 1sb111 is switched so as to supply AC power from the power supply path to the AC / DC power supply unit in response to a switch control signal (e.g., a second switching control signal) input from the LED module in the previous stage.

[0064] The switch 1sb111 receives a switch control signal output from the preceding cascaded LED module via the switch control input terminal 22t-1. The switch 1sb111 is OFF when the switch control signal is not input, and is ON when the switch control signal is input. When the switch 1sb111 is turned ON, AC power is supplied from the power supply path to the AC / DC power supply unit 1d11. When the switch 1sb111 is turned OFF, the supply of AC power to the AC / DC power supply unit 1d11 is cut off. The switch 1sb111 is an example of a second switch.

[0065] The switch 1sa112 switches whether or not to bypass the switch 1sb111 (second switch). When the switch 1sa112 is switched to bypass the switch 1sb111, AC power is supplied from the power supply path to the AC / DC power supply unit 1d11. A first terminal of the switch 1sa112 is connected to the power supply path between the power input terminal 23t-1 and the power output terminal 23t-2. A second terminal of the switch 1sb112 is connected to the power input terminal of the AC / DC power supply unit 1d11. The switch 1sa112 is manually switched between ON and OFF. When the switch 1sa112 is switched ON, AC power can be supplied to the AC / DC power supply unit 1d11 from the power supply path. When the switch 1sa112 is switched OFF, the supply of AC power to the AC / DC power supply unit 1d11 is cut off. The switch 1sa112 is an example of a fourth switch.

[0066] The switch 1sb11 switches whether or not direct current power is supplied from the AC / DC power supply unit 1d11 to the LED display unit 1b111. The switch 1sb11 is an example of a fifth switch.

[0067] 6 is a diagram showing an LED display system Sb in which three LED modules 1-21 shown in FIG. 5 are connected in a column direction (vertical direction). In this diagram, the LED modules are LED module 1-11, LED module 1-21, and LED module 1-31, which are connected in a row. Since the LED module 1-21 and the LED module 1-31 have the same functions as the LED module 1-11, the same names are used for corresponding components, some of the reference numerals are changed, and the following description will mainly focus on the different functions.

[0068] The switch 1sb-112 in the LED module 1-111 is manually set to ON. The switch 1sb-112 may be set to ON when initial setup is performed after the LED display system Sb is installed. The switch 1sb-112 may be always ON. By setting the switch 1sb-112 to ON, AC power can be supplied from the distribution board DB to the AC / DC power supply unit 1d11, regardless of whether the switch 1sb-111 is ON or not. Here, nothing is connected to the switch control input terminal 22t-1, so it is always OFF.

[0069] The switch 1sb-212 and switch 1sa-21 of the LED module 1-211, which is cascade-connected to the rear stage of the LED module 1-111, and the switch 1sb-312 and switch 1sa-31 of the LED module 1-311 are all OFF. Also, even when the LED module 1 is connected to the rear stage of the LED module 1-31, the state of each switch is OFF, just like the switch 1sb-212 and switch 1sa-21 of the LED module 1-211.

[0070] Furthermore, before a video signal is supplied to LED module 1-11, switch 1sb-211 of LED module 1-211, switch 1sb-311 of LED module 1-311, and the corresponding switches in the subsequent LED modules are in a state where no AC power is supplied to the AC / DC power supply units of the respective LED modules because the switch control signals supplied from the preceding LED modules are in an OFF state (or no input is provided).When AC power is supplied from distribution board DB, LED module 1-11 is supplied with AC power, and DC power is supplied from AC / DC power supply unit 1d11 to signal processing unit 1c111.

[0071] Here, when the supply of video signals from the LED controller LC is stopped, when looking at the LED display system Sb as a whole, the AC / DC power supply unit 1d11 and signal processing unit 1c111 within the LED module 1-111 are operating, but the operation of LED modules other than the LED module 1-111 and the LED display unit 1b111 of the LED module 1-111 are stopped and no power is being consumed.

[0072] Next, when a video signal is output from LED controller LC, video detector 1c11c in LED module 1-111 detects the video signal. In response to the detection of the video signal by video detector 1c11c, video detector 1c11c outputs the video signal detection result to switch controller 1c11d. In response to receiving this detection result, switch controller 1c11d sets switch 1sa11 to ON and outputs a switch control signal representing ON from switch control output terminal 22t-2. By setting switch 1sa11 to ON, DC power is supplied from AC / DC power supply 1d11 to LED display unit 1b11, and LED display unit 1b11 transitions to a state in which it can display an image. Furthermore, when a switch control signal representing ON is output from switch controller 1c11d via switch control output terminal 22t-2, the switch control signal is supplied to switch 1sb211 via switch control input terminal 22t-3. As a result, the switch 1sb211 is switched to the ON state.

[0073] Meanwhile, when a video signal is supplied from the LED controller LC to LED module 1-111 and then supplied to signal processing unit 1c111, video processing unit 1c11a generates an LED drive signal from the video signal and supplies it to LED display unit 1b11. LED display unit 1b11 receives DC power from AC / DC power supply unit 1d11 and receives an LED drive signal corresponding to the video signal from LED drive signal generation unit 1c11b, which drives each LED light-emitting unit in accordance with the LED drive signal. As a result, an image based on the video signal is displayed on LED display unit 1b11. Furthermore, when a video signal is supplied from the LED controller LC to signal processing unit 1c111 of LED module 1-11, signal processing unit 1c111 supplies the video signal to video signal output terminal 21t-2 via amplifier element 1c11e. The video signal supplied to video signal output terminal 21t-2 is supplied to signal processing unit 1c21 via video signal input terminal 21t-3 of LED module 1-21.

[0074] On the other hand, when switch 1sb211 in LED module 1-211 is set ON, AC power supplied from power input terminal 23t-3 is supplied to AC / DC power supply unit 1d21, and DC power is supplied from AC / DC power supply unit 1d21 to signal processing unit 1c211. Signal processing unit 1c211 in LED module 1-211 begins operating in response to the power supply. Signal processing unit 1c211 detects a video signal input via video signal input terminal 21t-3 using video detection unit 1c21c, and outputs a switch control signal from switch control unit 1c21d to switch 1sa21, thereby setting switch 1sa21 ON. Furthermore, signal processing unit 1c211 generates an LED drive signal corresponding to the video signal using LED drive signal generation unit 1c21b, and outputs it to LED display unit 1b21. As a result, LED display unit 1b21 displays an image based on the LED drive signal. Furthermore, when the switch control unit 1c21d of the LED module 1-211 sets the switch 1sa21 to ON, it outputs a switch control signal indicating ON from the switch control output terminal 22t-4. As a result, the switch control signal is supplied to the switch 1sb311, and the switch 1sa31 is set to ON. Then, AC power is supplied to the AC / DC power supply unit 1d31, and DC power is supplied from the AC / DC power supply unit 1d31 to the signal processing unit 1c311. Thereafter, power is supplied to the LED modules sequentially with time lags in a similar sequence, and an image corresponding to the video signal is displayed.

[0075] 7 is a diagram showing a case where the supply of a video signal is stopped in the LED display system Sb shown in FIG. 6. When AC power is being supplied from the distribution board DB, power is being supplied to the LED module 1-11. That is, AC power is being supplied to the AC / DC power supply unit 1d11 in the LED module 1-11. When a video signal is being output from the LED controller LC, the switches (1sa11, 1sb11, 1sa21, 1sb21, 1sa31, 1sb31) in all of the cascaded LED modules (1-11, 1-21, 1-31) are in the ON state.

[0076] When the video signal from the LED controller LC is stopped, the video detector 1c11c is put into a state where it does not detect a video signal, and the switches 1sa11 and 1sb11 in the LED module 1-11 are switched to the OFF state. Then, because the switch 1sa11 is switched to the OFF state, the supply of AC power to the subsequent LED modules 1-21 and 1-31 and the subsequent LED modules is stopped.

[0077] Then, as the video signal from the LED controller LC is stopped, the switch 1sb11 of the LED module 1-11 is also switched to the OFF state, and therefore no DC power is supplied to the LED display unit 1b11 of the LED module 1-11, and no power is consumed by the LED display unit 1b11. Therefore, the only part that is operating (where power is consumed) is the signal processing unit 1c11 in the LED module 1-11. In other words, even if AC power is supplied from the distribution board DB, the AC / DC power supply unit 1d11 of the LED module 1-11 converts the AC power to DC power and supplies the DC power to the signal processing unit 1c11, but no power is supplied from the LED module 1-11 to the LED modules in the next stage or later (1-21, etc.). Therefore, the part that consumes power is the signal processing unit 1c11 in the LED module 1-11, and no power is consumed by the LED display unit 1b11, nor by the LED modules after the LED module 1-21.

[0078] Here, when a video signal is output from the LED controller LC, the switches (1sa11, 1sb211, 1sa311, 1sa21, 1sa31, etc.) in all of the cascaded LED modules 1 are turned ON.

[0079] On the other hand, when the supply of the video signal from the LED controller LC is stopped, the video detector 1c11c in the LED module 1-11 detects the absence of a video signal, and accordingly, the switch controller 1c11d turns off the switch 1sa11 and sets off the switch 1sb211 in the LED module 1-21. When the switch 1sb211 is set off, the supply of AC power to the AC / DC power supply unit 1d21 is cut off, and the LED module 1-21 stops operating. As the operation of the LED module 1-21 stops, no switch control signal is supplied to the switch 1sbb311 in the LED module 1-31, so the switch 1sbb311 is turned off, the supply of AC power to the LED module 1-31 is stopped, and the operation of the LED module 1-31 stops. Thereafter, following a similar sequence, the supply of AC power to the AC / DC power supply units of the cascaded LED modules 1 is stopped, and operation stops. Furthermore, because the switch 1sa11 of the LED module 1-111 is also set to OFF, no power is supplied to the LED display unit 1b11 of the LED module 1-111, and therefore no power is consumed by the LED display unit 1b11. Here, the parts that are operating (that consume power) are the signal processing unit 1c111 and the AC / DC power supply unit 1d11 in the LED module 1-11.

[0080] Third Embodiment In the third embodiment, there are two types of LED module configurations. Fig. 8 is a schematic functional block diagram showing the configuration of a first type of LED module 1-112, and Fig. 9 is a schematic functional block diagram showing the configuration of a second type of LED module 1-113. For the LED module 1-112 and the LED module 1-113, the same functions as those of the corresponding configuration of the LED module 1-111 in the second embodiment are assigned the same reference numerals and their descriptions are omitted, while different functions are assigned different reference numerals and will be described.

[0081] LED module 1-112A is an example of an LED module connected to the first stage. LED module 1-112A has AC / DC power supply unit 1d111 and AC / DC power supply unit 1d112. AC / DC power supply unit 1d111 generates DC power capable of driving LED display unit 1b111 from AC power supplied from the power supply path when switch 1sa112 is ON. AC / DC power supply unit 1d112 converts AC power supplied from the power supply path connecting power input terminal 23t-1 and power output terminal 23t-2 into DC power and supplies the DC power to at least signal processing unit 1c111. Because the input terminal of AC / DC power supply unit 1d112 is connected to the power supply path, when AC power is supplied to power input terminal 23t-1, AC power is supplied to AC / DC power supply unit 1d112. That is, AC power is supplied regardless of whether the various switches in LED module 1-112A are ON or OFF. AC / DC power supply unit 1d112 is an example of a first-stage AC / DC power supply unit. AC / DC power supply unit 1d112 generates DC power from AC power that can drive signal processing unit 1c111. AC power is input from distribution board DB to power input terminal 23t-1, and AC power is supplied to AC / DC power supply unit 1d111. Furthermore, when switch 1sb112 is ON, the AC power supplied to power input terminal 23t-1 is supplied to AC / DC power supply unit 1d111 via switch 1sb112, and output from power output terminal 23t-2 to LED module 1-112B installed in the next stage.

[0082] A video signal output from LED controller LC is input to video signal input terminal 21t-1 and supplied to signal processing unit 1c111. Signal processing unit 1c111 includes video processing unit 1c11a, LED drive signal generation unit 1c11b, video detection unit 1c11c, switch control unit 1c11d, and amplifier element 1c11e. Signal processing unit 1c111 performs video processing on the input video signal and outputs a switch control signal to LED module 1-112B arranged in the next stage via switch control output terminal 22t-2.

[0083] Video detection unit 1c11c detects whether or not a video is present in the input video signal and outputs the detection result to switch control unit 1c11d2. When switch control unit 1c11d receives a detection result indicating whether or not a video is present in the video signal from video detection unit 1c11c, it outputs a switch control signal to switches 1sb12 and 1sb112 to set switches 1sb12 and 1sb112 ON or OFF in accordance with the detection result, and outputs the switch control signal from switch control output terminal 22t-2.

[0084] Video processing unit 1c11a extracts from the video signal the portion of the video to be displayed on its own LED module 1-112A, performs video processing on the extracted portion of the video, and outputs it to LED drive signal generation unit 1c11b. LED drive signal generation unit 1c11b generates an LED drive signal based on the processed video signal input from video processing unit 1c11a and outputs it to LED display unit 1b111. LED display unit 1b111 drives each LED light-emitting unit in accordance with the LED drive signal output from LED drive signal generation unit 1c11b. As a result, an image based on the video signal is displayed on LED display unit 1b11. Video detection unit 1c11c determines (detects) whether or not a video signal is being input from video signal input terminal 21t-1 (presence or absence of a video signal) and outputs the determination result to switch control unit 1c11d2.

[0085] In response to the video detection unit 1c11c (signal processing unit of the first-stage LED module) detecting a video signal, the switch control unit 1c11d2 supplies a switch control signal (third switching control signal) to the LED module 1-112B to switch the 1sb112 (second switch) of the LED module 1-112B connected in the subsequent stage of the LED module 1-112A (first-stage LED module).

[0086] In the LED module 1-112B of FIG. 9, functions corresponding to those of the LED module 1-111 of FIG. 5 are assigned the same reference numerals, and the following mainly describes the differences in configuration. The LED module 1-112B is an example of an LED module connected in the second or subsequent stage. The LED module 1-112B has a configuration in which the switch 1sa112 is removed from the LED module 1-111 of FIG. 5. Furthermore, while the LED module 1-112A of FIG. 8 has a configuration in which two AC / DC power supplies are provided and a switch control signal is output from the switch control unit 1c11d2 to two switches, the LED module 1-112B differs in that it has a configuration in which one AC / DC power supply unit 1d11 is provided and a switch control signal is output from the switch control unit 1c11d1 to one switch 1sb12.

[0087] In LED module 1-112B, when switch 1sb112 is ON, AC / DC power supply unit 1d11 converts AC power supplied from power input terminal 23t-1 into DC power and supplies it to signal processing unit 1c111 and the first terminal of switch 1sb12. Also, in LED module 1-112B, when switch 1sb112 is OFF, AC / DC power supply unit 1d11 converts AC power supplied from power input terminal 23t-1 into DC power and supplies it to signal processing unit 1c111 and the first terminal of switch 1sb12.

[0088] AC power output from an LED module arranged in a preceding stage is input to power input terminal 23t-1. This AC power is supplied to AC / DC power supply unit 1d11 via switch 1sb112, which is controlled based on a switch control signal input to switch control input terminal 22t-1, and is also supplied from power output terminal 23t-2 to the power input terminal of the LED module arranged in the following stage.

[0089] A video signal output from an LED module arranged in the preceding stage is input to video signal input terminal 21t-1 and supplied to signal processing unit 1c111. Signal processing unit 1c111 is composed of a video detection unit, switch control unit, video processing unit, and LED drive signal generation unit, and performs video processing on the input signal and outputs a signal from the signal output unit to the LED module arranged in the subsequent stage.

[0090] Signal processing unit 1c111 includes video processing unit 1c11a, LED drive signal generation unit 1c11b, video detection unit 1c11c, switch control unit 1c11d1, and amplifier element 1c11e. Signal processing unit 1c111 performs video processing on the input video signal and outputs a switch control signal to LED module 1-112B arranged in the next stage via switch control output terminal 22t-2.

[0091] The video detection unit 1c11c detects whether or not video is present in the input video signal, outputs the detection result to the switch control unit 1c11d1, sets the switch 1sb12 to ON or OFF, and supplies the detection result from the switch control output terminal 22t-2 to the LED module connected in the next stage.

[0092] Video processing unit 1c11a extracts from the video signal the video portion to be displayed on its own LED module 1-112A, performs video processing on the extracted video portion, and outputs it to LED drive signal generation unit 1c11b. LED drive signal generation unit 1c11b generates an LED drive signal based on the processed video signal input from video processing unit 1c11a and outputs it to LED display unit 1b111. LED display unit 1b111 drives each LED light-emitting unit in accordance with the LED drive signal output from LED drive signal generation unit 1c11b. As a result, an image based on the video signal is displayed on LED display unit 1b11.

[0093] 10 is a diagram showing the configuration of an LED display system Sc. In the LED display system Sc, two LED modules (1-212B, 1-312B) are connected in series in the column direction (vertical direction) to an LED module 1-112A. In this diagram, the LED modules 1-212B and 1-312B have the same functions as the LED module 1-112B, so the same names are used for corresponding components, some of the reference numerals are changed, and the following description will mainly focus on the different functions.

[0094] The first-stage LED module 1-112A is connected to the LED controller LC and the distribution board DB. Furthermore, while the LED module 1-112A is receiving AC power from the distribution board DB, AC power is supplied to the AC / DC power supply unit 1d112 via the power input terminal 23t-1. Therefore, DC power is supplied from the AC / DC power supply unit 1d112 to the signal processing unit 1c111 of the LED module 1-112A, and the signal processing unit 1c111 is in an operable state.

[0095] When AC power is being supplied from distribution board DB and a video signal is not being supplied from LED controller LC via video signal input terminal 21t-1, video detection unit 1c11c does not detect a video signal. Based on this detection result, switch control unit 1c11d sets switches 1sb12 and 1sb112 to OFF and outputs a switch control signal via switch control output terminal 22t-2. As a result, switch 1sb212 of LED module 1-212B is set to OFF based on the switch control signal. As a result, the supply of AC power from power input terminal 23t3 to AC / DC power supply unit 1d21 is cut off, and no power is consumed in LED module 1-211B.

[0096] Furthermore, because no AC power is supplied to the LED module 1-212B, no switch control signal is output from the switch control unit 1c21d of the LED module 1-212B to the switch 1sb312 of the LED module 1-311B. As a result, the supply of AC power to the AC / DC power supply unit 1d31 of the LED module 1-312B is cut off, and no power is consumed by the LED module 1-312B. If subsequent LED modules are connected to the LED module 1-312B, no power is consumed by these subsequent LED modules either.

[0097] On the other hand, when AC power is supplied from the distribution board DB and a video signal is supplied from the LED controller LC via the video signal input terminal 21t-1, the video detection unit 1c11c of the LED module 1-112A detects the video signal. In response to the detection of the video signal, the switch control unit 1c11d sets the switch 1sa112 and the switch 1sb12 to ON, and supplies a switch control signal to the switch 1sb212 via the switch control output terminal 22t-2 and the switch control input terminal 22t-3, thereby setting the switch 1sb212 to ON.

[0098] Furthermore, video processing unit 1c11a of LED module 1-112A extracts the video portion to be displayed on its own LED module 1-112A from the input video signal, performs video processing on the extracted video portion, and outputs it to LED drive signal generation unit 1c11b. LED drive signal generation unit 1c11b generates an LED drive signal based on the processed video signal input from video processing unit 1c11a and outputs it to LED display unit 1b11. LED display unit 1b11 is supplied with DC power from AC / DC power supply unit 1d111, and when LED drive signal generation unit 1c11b supplies an LED drive signal corresponding to the video signal, it drives each LED light-emitting unit in accordance with the LED drive signal. As a result, an image based on the video signal is displayed on LED display unit 1b11. Furthermore, the signal processing unit 1c211 outputs the video signal supplied from the video signal input terminal 21t-3 to the signal processing unit 1c211 of the LED module 1-212B via the amplifying element 1c11e and the video signal output terminal 21t-2 and the video signal input terminal 21t-3.

[0099] Next, in the LED module 1-212B, when the switch 1sb212 is set ON, the AC / DC power supply unit 1d21 is activated and DC power is supplied to the signal processing unit 1c211 and the first terminal of the switch 1sb22. When AC power is supplied from the LED module 1-112A, a switch control signal is input from the switch control input terminal 22t-3, and a video signal is input from the video signal input terminal 21t-3, the signal processing unit 1c211 of the LED module 1-112A detects the video signal and sets the switch 1sb22 ON, and also supplies a switch control signal to the switch 1sb312 via the switch control output terminal 22t-4 and the switch control input terminal 22t-5, thereby setting the switch 1sb312 ON.

[0100] Furthermore, the signal processing unit 1c211 of the LED module 1-212B extracts from the input video signal the video portion to be displayed by its own LED module 1-212B, performs video processing on the extracted video portion, and then generates an LED drive signal to output to the LED display unit 1b21. When the LED display unit 1b21 is supplied with DC power from the AC / DC power supply unit 1d21 and receives an LED drive signal corresponding to the video signal from the LED drive signal generation unit 1c21b, it drives each LED light-emitting unit in accordance with the LED drive signal. As a result, an image based on the video signal is displayed on the LED display unit 1b21.

[0101] When switch 1sb212 is turned ON and AC power is supplied to AC / DC power supply unit 1d21, AC / DC power supply unit 1d21 starts up and supplies DC power to signal processing unit 1c211. As a result, video detection unit 1c21c in LED module 1-212B detects a video detection signal, and switch control unit 1c21d sets switch 1sb22 ON and also sets switch 1sb312 of LED module 1-312B ON via switch control output terminal 22t-4 and switch control input terminal 22t-5. Thereafter, power is supplied to subsequent LED modules in a similar sequence with a time lag, the LED modules start up, and images corresponding to the video signal are displayed.

[0102] Next, when the video signal output from the LED controller LC disappears, the video detector 1c11c of LED module 1-112A detects the absence of a video signal and outputs the detection result to the switch controller 1c11d. When the detection result indicating the absence of a video signal is input, the switch controller 1c11d sets the switches 1sb12 and 1sa112 to OFF, and also sets the switch 1sb212 of the LED module 1-211B to OFF. When the switch 1sb11 is set to OFF, the supply of DC power to the LED display unit 1b11 is cut off. This stops power consumption in the LED display unit 1b11. Furthermore, when the switch 1sa112 is set to OFF, the supply of AC power to the AC / DC power supply unit 1d111 is cut off. This stops power consumption in the AC / DC power supply unit 1d111.

[0103] The LED module 1-212B stops operating in response to the interruption of the supply of AC power to the AC / DC power supply unit 1d21. This stops the power consumption of the LED module 1-211B. Furthermore, when the operation of the LED module 1-211B stops, the switch control signal is not supplied from the LED module 1-211B to the LED module 1-312B, and therefore the switch 1sb312 is set to off. This causes the operation of the AC / DC power supply unit 1d31 to stop in response to the interruption of the supply of AC power to the AC / DC power supply unit 1d31, the operation of the entire LED module 1-311B to stop, and the power consumption of the LED module 1-312B to stop. If an LED module 1 is connected in a stage subsequent to the LED module 1-312B, the operation of all of the LED modules in the stages subsequent to the LED module 1-312B is also stopped. At this time, the signal processing unit 1c111 and AC / DC power supply unit 1d112 of the first-stage LED module 1-112A are operating, but the operation of the other units is stopped.

[0104] <<Fourth Embodiment>> Fig. 11 is a diagram showing the configuration of an LED display system Sd. The LED display system Sd is provided with an LED module 1-112B instead of the LED module 1-112A in the LED display system Sc shown in Fig. 10, and an LED controller LCA instead of the LED controller LC. The LED module 1-112B has the same functions as the LED module 1-112B shown in Fig. 9, so the same names are used for corresponding components, some of the reference numerals have been changed, and the following description will mainly focus on the different functions.

[0105] Among the multiple LED modules, the switch 1sa112 (second switch) of the first-stage LED module 1-112B is switched to supply AC power from the power supply path to the AC / DC power supply unit by a control signal supplied from an external device (for example, an LED controller LCA). Although the case where this control signal is supplied from the LED controller LCA will be described, it may also be supplied from a device other than the LED controller LCA.

[0106] The LED controller LCA has the same functions as those of the first to third embodiments. Furthermore, when supplying a video signal to the video signal input terminal 21t-1 of the LED module 1-112B, the LED controller LCA supplies a switch control signal to the switch control input terminal 22t-1 of the LED module 1-112B to switch the switch 1sa112 ON. Furthermore, when stopping the supply of the video signal to the video signal input terminal 21t-1 of the LED module 1-112B, the LED controller LCA supplies a switch control signal to the switch control input terminal 22t-1 of the LED module 1-112B to switch the switch 1sa112 OFF.

[0107] In the LED display system Sc of the third embodiment, DC power is constantly supplied from the distribution board DB to the AC / DC power supply unit 1d112 of the LED module 1-112A. However, in the LED display system Sd of the fourth embodiment, the switch 1sa112 of the LED module 1-112B is switched ON or OFF based on a switch control signal supplied from the LED controller LCA. Therefore, in response to the supply of a video signal from the LED controller LCA, the switch 1sa112 is switched ON, thereby supplying AC power to the AC / DC power supply unit 1d11. Furthermore, in response to the stop of the supply of the video signal from the LED controller LCA, the switch 1sa112 is switched OFF, thereby cutting off the supply of AC power to the AC / DC power supply unit 1d11.

[0108] Here, in the LED display system Sc shown in Fig. 10, the first-stage LED module 1-112A is provided with two AC / DC power supply units, AC / DC power supply unit 1d111 and AC / DC power supply unit 1d112, but in the LED display system Sd shown in Fig. 11, the first-stage LED module 1-112B only needs to have a single AC / DC power supply unit 1d11. Therefore, in the LED display system Sd, even the first-stage LED module can have the same configuration as the LED modules in the subsequent stages. Therefore, it is not necessary to increase the number of types of LED modules required to build one LED display system.

[0109] According to the first to third embodiments described above, power can be supplied or cut off depending on whether a video signal is detected in the LED module without an operator having to directly operate the distribution board DB, which makes it possible to easily manage power consumption.

[0110] Furthermore, according to the second and third embodiments, when no video signal is output from the video source device, the signal processing unit of the first-stage LED module connected to the LED controller only needs to operate, so power is not supplied to other LED modules, thereby reducing power consumption when no video is displayed in the LED display system. For example, when no video signal is supplied to the LED display and no video is to be displayed on the LED display, simply cutting off the video signal by turning off the power to the video source device would leave power supplied to the LED module, and although the LED panel would be turned off, the signal processing unit within the LED module would remain operational, resulting in unnecessary power consumption. However, according to the second and third embodiments, when no video signal is output from the video source device, as long as the signal processing unit of the first-stage LED module connected to the LED controller is operating, the signal processing units and LED panels of subsequent LED modules do not need to be driven, thereby reducing power consumption.

[0111] Furthermore, in the second to fourth embodiments, the signal processing unit of each LED module may be configured to, upon receiving a video signal from a preceding LED module or the LED controller LC, supply the video signal to the LED module connected thereto and then execute a process of supplying power to the following LED module.The signal processing unit of each LED module may then cause the LED display unit to display an image based on the video signal.Furthermore, the LED display units of each LED module may be configured to synchronize their timing so that, after the video signal is supplied from the LED controller LC to the LED display LD, images corresponding to the video signal are simultaneously displayed.

[0112] Furthermore, when power supply to each LED module is started, it is possible to set a time difference between the start of power supply to each LED module, which spreads out the timing of inrush current generation in each LED module, preventing the distribution board from tripping (shutting off) and allowing for a smooth start of power supply.

[0113] Furthermore, the greater the number of LED modules that make up the LED display, the greater the amount of power consumption that can be reduced when no video signal is detected.

[0114] In the above-described embodiment, the LED modules are arranged in series vertically relative to the first-stage LED module. However, the LED modules may also be arranged in series horizontally relative to the first-stage LED module. For example, the video signal input terminal and the power input terminal may be arranged along a first vertical edge of the periphery of the LED module, and the signal output terminal and the power output terminal may be arranged along a second vertical edge. This allows multiple LED modules to be connected in series horizontally. Furthermore, for example, the video signal input terminal, the switch control input terminal, and the power input terminal may be arranged along a first vertical edge of the periphery of the LED module, and the signal output terminal, the switch control output terminal, and the power output terminal may be arranged along a second vertical edge. This allows multiple LED modules to be connected in series horizontally.

[0115] 1 may be recorded on a computer-readable recording medium, and the program may be read into a computer system and executed to perform construction management. Note that the term "computer system" here includes hardware such as the OS and peripheral devices.

[0116] Furthermore, if a WWW system is used, the term "computer system" also includes the homepage provision environment (or display environment). Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into computer systems. Furthermore, "computer-readable recording medium" also includes devices that retain programs for a certain period of time, such as volatile memory within a computer system that serves as a server or client. The program may be one that realizes part of the aforementioned functions, or it may be one that realizes the aforementioned functions in combination with a program already stored in the computer system. The program may also be stored on a designated server, and distributed (e.g., downloaded) via a communication line in response to requests from other devices.

[0117] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0118] 1-11, 1-111, 1-111A, 1-112, 1-112A, 1-112B, 1-113, 1-12, 1-13, 1-14, 1-15, 1-16, 1-17, 1-18, 1-19, 1-1m, 1-20, 1-21, 1-21 1, 1-211b, 1-211B, 1-212B, 1-22, 1-23, 1-24, 1-25, 1-26, 1-27, 1-28, 1-29, 1-30, 1-31, 1-311, 1-311B, 1-312B, 1-n1, 1-311B LED module 1b11, 1b21, 1b31, 1b111 LED display section 1sb111, 1sb112, 1sb12, 1sb21 Switch 1c11c, 1c21c Video detection unit 1c11a Video processing unit 1c11, 1c31, 1c311, 1c111 Signal processing unit 1c11b LED drive signal generation unit 1c11d, 1c11d1, 1c11d2 Switch control unit 1c11e Amplification element 1c21b LED drive signal generation unit 1c21d Switch control unit 1c21e Amplification element 1d11, 1d11, 1D11, 1d111, 1d112, 1d21, 1d31 AC / DC power supply unit 1EB, 1EB1 Electrical board 1da11, 1da21, 1sa, 1sa11, 1sa112, 1sa21, 1sa31, 1sb, 1sb11, 1sb211, 1sb212, 1sb22, 1sb31, 1sb311, 1sb312, 1sbb311 Switch 21t-1, 21t-3, 21t-5 Video signal input terminal 21t-2, 21t-4 Video signal output terminal 22t-1, 22t-3, 22t-5 Switch control input terminal 22t-2, 22t-4 Switch control output terminal 23t-1, 23t-3, 23t-5 Power input terminal 23t-2, 23t-4 Power output terminal DB Distribution board LC, LCA LED controller LD LED display LDP LED panel PC Power cable S, Sa, Sb, Sc, Sd LED display system SC Signal cable VS Video source equipment

Claims

1. An LED display device in which a plurality of LED modules are arranged, the LED modules comprising: a display unit equipped with a plurality of LED elements; a signal processing unit that causes the display unit to display an image based on a video signal supplied from an external device; a power input port into which AC power is input from the outside; a power output port that is capable of supplying the AC power input to the power input port to a subsequent LED module; an AC / DC power supply unit that converts the AC power supplied from a power supply path connecting the power input port and the power output port into DC power and supplies the DC power to at least the signal processing unit; a first switch that is provided in the power supply path and switches whether the AC power input to the power input port is to be supplied to the power output port; a video signal input port into which the video signal is input; and a video output port that is capable of supplying the video signal input to the video signal input port to the subsequent LED module. a switch control unit that supplies a first switching control signal to the first switch, causing the first switch to switch so that AC power input to the power input port is supplied to the power output port, in response to the signal processing unit detecting the video signal.

2. The LED display device according to claim 1, wherein, after the signal processing unit supplies the video signal to the subsequent LED module, the switch control unit switches the first switch so as to supply the AC power to the power output port, and the signal processing unit displays an image based on the video signal on the display unit.

3. An LED display device in which a plurality of LED modules are arranged, the LED modules having: a display unit equipped with a plurality of LED elements; a signal processing unit that causes the display unit to display an image based on a video signal supplied from a preceding LED module; a power input port to which AC power is input from the preceding LED module; a power output port that can supply the AC power input to the power input port to a succeeding LED module; an AC / DC power supply unit that converts the AC power supplied from a power supply path connecting the power input port and the power output port into DC power and supplies the DC power to at least the signal processing unit; a second switch that switches whether AC power is supplied from the power supply path to the AC / DC power supply unit; a video signal input port to which the video signal is input; and a video output port that can supply the video signal input to the video signal input port to the succeeding LED module, the second switch being switched to supply AC power from the power supply path to the AC / DC power supply unit in response to a second switching control signal input from the preceding LED module, the LED module further includes a switch control unit that supplies a third switching control signal to the subsequent LED module in response to the signal processing unit detecting the video signal, the third switching control signal switching the second switch of the subsequent LED module.

4. The LED display device according to claim 3, wherein after the signal processing unit supplies the video signal to the subsequent LED module, the switch control unit supplies the third switching control signal to the subsequent LED module, and the signal processing unit causes the display unit to display an image based on the video signal.

5. The LED display device according to claim 3, wherein an initial stage LED module among the plurality of LED modules has a fourth switch that switches whether or not to bypass the second switch, and the fourth switch is switched to bypass the second switch, thereby supplying AC power from the power supply path to the AC / DC power supply unit.

6. The LED display device according to claim 3, wherein an initial stage LED module of the plurality of LED modules comprises: the display unit; the signal processing unit; a power input port to which AC power is input from an external device; a power output port capable of supplying the AC power input to the power input port to a subsequent stage LED module; a video signal input port to which a video signal supplied from an external device is input; a video output port capable of supplying the video signal input to the video signal input port to the subsequent stage LED module; an initial stage AC / DC power supply unit that converts AC power supplied from a power supply path connecting the power input port and the power output port into DC power and supplies the DC power to at least the signal processing unit; and the switch control unit, wherein the switch control unit of the initial stage LED module supplies a third switching control signal to the LED module connected to the subsequent stage, the third switching control signal switching a second switch of the LED module connected to the subsequent stage in response to the signal processing unit of the initial stage LED module detecting the video signal.

7. The LED display device according to claim 3, wherein the second switch of the first-stage LED module among the plurality of LED modules is switched to supply AC power from the power supply path to the AC / DC power supply unit in response to a control signal supplied from an external device.

8. An LED display device according to any one of claims 1 to 6, wherein the signal processing unit operates in response to the input of DC power from the AC / DC power supply unit, thereby supplying a video signal input to the video signal input port from the video output port to the LED module in the subsequent stage.

9. The LED display device according to any one of claims 1 to 8, further comprising a fifth switch for switching whether or not DC power is supplied from the AC / DC power supply unit to the display unit, and the signal processing unit operates in response to DC power being input from the AC / DC power supply unit, thereby supplying a fourth switching control signal to the fifth switch for switching the fifth switch so that DC power is supplied from the AC / DC power supply unit to the display unit.

10. The LED display device according to claim 9, wherein the switch control unit supplies a fourth switching control signal to the fifth switch, which switches the fifth switch so that direct current power is not supplied from the AC / DC power supply unit to the display unit, in response to the signal processing unit not detecting the video signal.

11. A control method for an LED display device in which a plurality of LED modules are arranged, each having the following features: a display unit equipped with a plurality of LED elements; a signal processing unit that causes the display unit to display an image based on a video signal supplied from an external device; and a first switch that switches whether or not AC power supplied from the outside is supplied to an LED module connected in a subsequent stage, wherein the AC power supplied from the outside is converted into DC power and supplied to the signal processing unit, and when the DC power is supplied, the signal processing unit supplies the video signal input from the outside to the LED module in the subsequent stage, and in response to detecting the video signal, the signal processing unit supplies a first switching control signal to the first switch that switches the first switch so that the AC power is supplied to the LED module in the subsequent stage.

12. A control method for an LED display device in which a plurality of LED modules are arranged, each having the following features: a display unit equipped with a plurality of LED elements; a signal processing unit that causes an image based on a video signal supplied from a preceding LED module to be displayed on the display unit; and a second switch that switches whether or not AC power supplied from the preceding LED module is supplied to an AC / DC power supply unit, wherein the second switch switches to supply the AC power to the AC / DC power supply unit in response to a switching control signal being supplied from the preceding LED module to the second switch, the AC power is converted by the AC / DC power supply unit to DC power and supplied to the signal processing unit, when the DC power is supplied, the signal processing unit supplies an externally input video signal to the subsequent LED module, and the signal processing unit detects the video signal and supplies a third switching control signal to the subsequent LED module for switching the second switch of the subsequent LED module.

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