LED display device and connection method for LED modules

Abstract

This LED display device includes: a first path (21A2) to which, in an LED module (10-11) and an LED module (10-21) connected to the next stage, a signal processing unit of the LED module (10-11) and a signal processing unit of the LED module (10-21) are connected, and through which signals including a video signal are supplied; a second path (22A2) which is connected to the signal processing unit of the LED module (10-11) and LED modules from the next stage onward of the LED module (10-11), and through which a power supply control signal for supplying power from a power supply unit of an LED module to which the power supply control signal is to be supplied, among the LED modules from the next stage onward, to a signal processing unit of this LED module; and a third path (23A2) to which a power supply unit of the LED module (10-11) and a power supply unit of the LED module (10-21) are connected and through which power supplied from outside to the power supply unit of the LED module (10-11) is supplied to the power supply unit of the LED module (10-21).

Description

LED display device and LED module connection method

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

[0002] There is an LED display device that is composed of multiple LED (Light Emitting Diode) modules and displays images in response to a video signal. Such an LED display device is connected to a power supply device, which supplies power to the LED display device. The power supplied from the power supply device is supplied to each LED module of the LED display device.

[0003] 2. Description of the Related Art In a lighting device including a light-emitting element, there is a cutoff circuit that cuts off power supplied to the light-emitting element based on control from a control circuit (see, for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2022-036630

[0005] However, in an LED display device, when power is supplied from a power supply device, the circuitry within the LED module operates and consumes power even when no image is displayed. Note that Patent Document 1 is intended to suppress the dim lighting of the light source when the light is turned off, but is not intended to reduce the power consumption of the LED module.

[0006] One aspect of the present invention is an LED display device in which a plurality of LED modules are arranged, each LED module 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 a video signal supplied from an external device, and a power supply unit that supplies power supplied from the outside to at least the signal processing unit, wherein a first LED module among the plurality of LED modules and a second LED module connected to the first LED module have: a first path that connects the signal processing unit of the first LED module to the signal processing unit of the second LED module and supplies a signal including a video signal; a second path that connects the signal processing unit of the first LED module to a power supply unit of the second LED module and supplies a power control signal for supplying power from the power supply unit of the second LED module to the signal processing unit of the second LED module; and a third path that connects the power supply unit of the first LED module to the power supply unit of the second LED module and supplies power supplied from the outside to the first LED module to the power supply unit of the second LED module.

[0007] Another aspect of the present invention is a method for connecting a first LED module among the plurality of LED modules to a second LED module connected in a next stage to the first LED module in an LED display device in which the first LED module and the second LED module are arranged, the method comprising: connecting the signal processing unit of the first LED module to the signal processing unit of the second LED module by a first path; supplying a signal including a video signal via the first path; connecting the signal processing unit of the first LED module to a power supply unit of the second LED module by a second path; supplying a power control signal for supplying power from the power supply unit of the second LED module to the signal processing unit of the second LED module via the second path; connecting the power supply unit of the first LED module to the power supply unit of the second LED module by a third path; and supplying power supplied from the outside to the power supply unit of the first LED module to the power supply unit of the second LED module via the third path.

[0008] According to the present invention, it is possible to reduce power consumption when no video is displayed.

[0009] 1 is a schematic configuration diagram of a display system S including an LED display device according to the present embodiment. FIG. 1 is a schematic configuration diagram showing the configuration of an LED display device 1. FIG. 2 is a side view of one LED module 10 as seen from the side. FIG. 3 is a schematic functional block diagram explaining the configuration of a first LED module and a second LED module. FIG. 4 is a functional block diagram explaining the function of a power supply unit 10d11. FIG. 5 is a functional block diagram explaining the function of a power supply unit 10d11. FIG. 6 is a functional block diagram showing the configuration of an LED module 10-21a. FIG. 7 is a diagram showing a specific example of the configuration of a delay circuit 10e. FIG. 8 is a functional block diagram showing the schematic configuration of a signal processing unit 10c11. FIG. 9 is a functional block diagram showing the schematic configuration of a signal processing unit 10c11-1. FIG. 10 is a schematic functional block diagram explaining a configuration for outputting a power supply control signal. FIG. 11 is a schematic functional block diagram explaining another example of a configuration in which an LED module 10-11 outputs a power supply control signal. FIG. 12 is a schematic functional block diagram showing another configuration of an LED module 10. FIG. 13 is a diagram showing an example of calculation of power consumption of an LED display device.

[0010] An LED display device according to one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a display system S including an LED display device according to this embodiment. The display system S includes an LED display device 1, a distribution board 2, a video signal supply device 3, and an LED controller 4. The LED display device 1 is connected to the distribution board 2 via a power line and receives power from the distribution board 2. The LED display device 1 is also connected to the LED controller 4 via a communication line. The LED display device 1 includes a plurality of LED modules 10. In the LED display device 1, the plurality of LED modules 10 are arranged adjacent to each other in both the vertical and horizontal directions. In this figure, the plurality of LED modules 10 are arranged six vertically and six horizontally, for a total of 36 LED modules 10. The LED display device 1 displays an image based on a video signal using the entire display area of ​​the plurality of LED modules.

[0011] The switchboard 2 supplies power to the LED display device 1. The supplied power is, for example, an alternating current (AC) power supply.

[0012] The video signal supply device 3 is connected to the LED controller 4 via a communication line and is a supply source that outputs a video signal to the LED controller 4. The specifications of the communication line connecting the video signal supply device 3 and the LED controller 4 comply with one of the standards such as DVI I / F or HDMI (registered trademark) I / F. The video signal supply device 3 may be, for example, a computer.

[0013] The LED controller 4 supplies various signals to the LED modules. The various signals include, for example, a video signal and a startup signal. The LED controller 4 is an example of an external device. The LED controller 4 outputs the video signal output from the video signal supply device 3 to the LED display device 1. For example, the LED controller 4 divides the video signal output from the video signal supply device 3 according to the arrangement of the LED modules 10, converts it into a video signal in a format that can be received by the LED modules 10, and outputs it to the LED modules. The LED controller 4 also has a Wake-on-LAN function and generates and transmits Wake-on-LAN packets representing various signals. The various signals transmitted by the LED controller 4 include, for example, a startup signal and an OFF command. The startup signal may be, for example, a WOL (Wake-on-LAN) command or an ON command. The startup signal is a control signal that instructs the LED modules to start up. The OFF command is a command that instructs the display of the image based on the video signal to be hidden.

[0014] 2 is a schematic diagram showing the configuration of the LED display device 1. In the LED display device 1, six LED modules 10 are arranged vertically and six are arranged horizontally, for a total of 36 LED modules 10. One LED module (e.g., LED module 10-11) is composed of a plurality of pixel cards 10-0. For example, the LED module 10-11 is arranged in the bottom row (first row) of the leftmost column (first column), and the LED module 10-21, LED module 10-31, LED module 10-41, LED module 10-51, and LED module 10-61 are arranged in that order above it and electrically connected in series.

[0015] Furthermore, LED modules 10-12, 10-13, ... are arranged in order to the right of LED module 10-11. Here, the LED modules 10 in each row are connected in series with the LED modules 10 adjacent to them in the vertical direction via a communication cable (e.g., a LAN (Local Area Network) cable). Furthermore, the first LED module 10 in each row is connected to the LED controller 4 via a communication cable (e.g., a LAN cable). More specifically, LED module 10-11 is electrically connected to the LED controller 4 via a communication cable 21A1, and LED module 10-12 is electrically connected to the LED controller 4 via a communication cable 21B1. As a result, various signals (at least one of a start signal and a video signal) output from the LED controller 4 are supplied to the first LED module 10 in each row. The first LED module 10 in each row outputs various signals to the LED module 10 connected to the next row via the communication cable. As a result, various signals (activation signal, activation signal, etc.) are transmitted sequentially from the LED module 10 in the first row to the LED module 10 in the last row in each column.

[0016] Furthermore, of the LED modules 10 in the bottom row of each column of LED modules 10, two adjacent LED modules 10 are connected to the distribution board 2 and supplied with AC power. For example, a power line 21 connected to the distribution board 2 is connected to the LED module 10-11 and the LED module 10-12. As a result, AC power is supplied from the power line 21 to the first column of module groups including the LED module 10-11 and the second column of module groups including the LED module 10-12. Furthermore, a power line 22 connected to the distribution board 2 is connected to the LED module 10-13 and the LED module 10-14. As a result, AC power is supplied from the power line 22 to the third column of module groups 10-13G including the LED module 10-13 and the fourth column of module groups 10-14G including the LED module 10-14. Similarly, the LED module 10-15 and the LED module 10-16 are connected to the distribution board 2.

[0017] 3 is a side view of one LED module 10. In the LED module 10, a display unit 10b is configured on a first surface of an LED substrate 10a. The display unit 10b has a plurality of LED elements 10ele mounted on the first surface of the LED substrate 10a. Each LED element 10ele configures one pixel.

[0018] A signal processing unit 10c and a power supply unit 10d are attached to a second surface of the LED substrate 10a, which is the surface opposite to the first surface.

[0019] The signal processing unit 10c is connected to the LED controller or the signal processing unit of the preceding LED module, processes the video signal received from the LED controller or the signal processing unit of the preceding LED module, drives the LED elements of the display unit 10b, and displays an image corresponding to the video signal. The signal processing unit 10c includes an LED driver IC 10dl and a signal processing module 10mod. The LED driver IC 10dl is connected to at least one LED element 10ele and lights the connected LED element 10ele in response to the video signal. The signal processing module 10mod performs various signal processing. The signal processing unit 10c is also connected to the preceding LED module 10 or the LED controller 4, inputs the video signal output from the LED controller 4, and outputs the video signal to the LED module 10 connected to the following LED module 10 in the same column as the LED module 10.

[0020] When AC power is supplied from the switchboard 2, the power supply unit 10d converts the AC power into DC power and supplies the converted DC power to each circuit in the LED module. The power supply unit 10d also converts the power into voltages suitable for the display unit 10b and the signal processing unit 10c and supplies them to them.

[0021] 4 is a schematic functional block diagram illustrating the configuration of a first LED module and a second LED module connected in the next stage of the first LED module among the plurality of LED modules 10. Here, for example, the first LED module is the LED module 10-11, and the second LED module is the LED module 10-21.

[0022] LED module 10-11 includes a power supply unit 10d11, a signal processing unit 10c11, and a display unit 10b1. LED module 10-11 also has terminals 21t1, 23t1, 21t2, 22t2, and 23t2. LED module 10-21 also includes a power supply unit 10d21, a signal processing unit 10c21, and a display unit 10b2. LED module 10-21 also has terminals 21t3, 22t3, 23t3, 21t4, 22t4, and 23t4. In this way, the LED display device 1 has a plurality of LED modules arranged, each of which includes a display unit, a signal processing unit, and a power supply unit.

[0023] The terminal 23t1 is connected to the power supply line 23A from outside the LED module 10-11. An end of the power supply line 23A other than the end connected to the terminal 23t1 is connected to the switchboard 2. As a result, power is supplied from the switchboard 2 to the terminal 23t1.

[0024] Terminal 23t1 and terminal 23t2 are connected by power line 23A1. A power line branching from power line 23A1 is connected between connection point T1 of power line 23A1 and power supply unit 10d11. This allows AC power to be supplied from switchboard 2 to power supply unit 10d11.

[0025] Power supply unit 10d11 receives AC power from switchboard 2 via a power line branched from power line 23A1, converts the AC power to DC power, and supplies it to signal processing unit 10c11 via connection line 10d1a. Signal processing unit 10c11 can be driven by the power supplied via connection line 10d1a. Power supply unit 10d11 is provided with a switching unit that switches whether or not power is supplied to signal processing unit 10c11 (described below). In this diagram, ON signal supply unit 10d1-1 is provided to the switching unit of power supply unit 10d11 of the first-stage LED module 10 to which AC power is supplied, and supplies an ON signal to switch power to signal processing unit 10c11. Therefore, power supply unit 10d11 supplies DC power to signal processing unit 10c11 in response to AC power being supplied from power line 23A1.

[0026] Terminal 23t2 and terminal 23t3 are connected by third path 23A2. This electrically connects the power supply line between terminals 23t1 and 23t2 of LED module 10-11 and the power supply line between terminals 23t3 and 23t4 of LED module 10-21. A power supply unit 10d11 is connected to the power supply line between terminals 23t1 and 23t2 of LED module 10-11. A power supply unit 10d21 is connected to the power supply line between terminals 23t3 and 23t4 of LED module 10-21. The third path is, for example, a power line capable of supplying AC power. In other words, the third path connects the power supply unit of the first LED module and the power supply unit of the second LED module, and supplies power externally supplied to the first LED module to the power supply unit of the second LED module. For example, the third path 23A2 connects the power supply unit 10d11 of the LED module 10-11 to the power supply unit 10d2 of the LED module 10-21, and supplies the power supplied to the LED module 10-11 from the distribution board 2 to the power supply unit 10d2. The third path 23A3 connects the power supply unit 10d21 of the LED module 10-21 to the power supply unit of the LED module 10-31 connected in the next stage of the LED module 10-21, and supplies the power supplied from the distribution board 2 to the power supply unit. The third path is, for example, a power line capable of supplying power. The third path may be any path capable of supplying power, and may be, for example, a cable with a set of three wires: live, neutral, and ground. The third path will be described as a path connecting a terminal of an LED module and a terminal of the LED module 10 in the next stage of the LED module. However, the third path may also be a path connecting a power supply unit of an LED module and a power supply unit of the LED module 10 in the next stage of the LED module.

[0027] A terminal 21t1 of the LED module 10-11 is connected to a communication cable 21A1 outside the LED module 10-11. An end of the communication cable 21A1 other than the end connected to the terminal 23t1 is connected to the LED controller 4. As a result, a wake-up signal (Wake-on-LAN packet) from the LED controller 4 is supplied to the terminal 21t1.

[0028] When the signal processing unit 10c11 receives a wake-up signal from the LED controller 4, it generates a power supply control signal and supplies it to the power supply unit 10d2 of the LED module 10-21 connected downstream via the second path 22A2. Here, the LED controller 4 converts the wake-up signal into a Wake-on-LAN packet and transmits it to the signal processing unit 10c11 of the LED module 10-11. The signal processing unit 10c11 can turn on the power supply unit of the downstream LED module 10 by transmitting the packet to the downstream LED module 10 via the second path. Note that while the case where a Wake-on-LAN packet is used as the wake-up signal has been described, a unique ON command predetermined between the LED controller 4 and the signal processing unit 10c11 may be used instead of the Wake-on-LAN packet as long as it can turn on the power.

[0029] The power supply control signal may be any signal that can cause the power supply unit 10d2 to supply power to the signal processing unit 10c2.

[0030] The first connection line of signal processing unit 10c11 is connected to terminal 22t2. Terminal 22t2 and terminal 22t3 are communicatively connected by second path 22A2. That is, the second path is a path connecting the signal processing unit of the first LED module to the LED modules next to the first LED module, and supplies a power control signal that causes the power supply unit of the target LED module to supply power to the signal processing unit of the target LED module among the LED modules next to the first LED module. For example, second path 22A2 connects signal processing unit 10c11 of LED module 10-11 to power supply unit 10d2 of LED module 10-21, and supplies the power control signal supplied from signal processing unit 10c11 to power supply unit 10d2. Second path 22A3 is a path that supplies the power control signal output from signal processing unit 10c11 of LED module 10-11 to the power supply unit of LED module 10-31, which is connected next to LED module 10-21. Here, in the LED module 10-21, a supply path 22A21 is provided electrically connecting the terminals 22t3 and 22t4, and the power control signal supplied from the signal processing unit 10c11 is supplied to the LED module 10-31 in the next stage via the second path 22A3. While the second path will be described as a path connecting a terminal of an LED module and a terminal of an LED module 10 in the next stage of the LED module, it may also be a path connecting a signal processing unit of an LED module and a power supply unit of an LED module 10 in the next stage of the LED module. The second path may be a path connecting the signal processing unit of a first LED module to the LED modules in the next stage or later of the first LED module. In this case, the LED modules in the next stage or later may be LED modules adjacent to the first LED module. Furthermore, the LED modules in the next stage or later may be LED modules arranged in a plurality of LED modules that are not adjacent to the first LED module (e.g., the LED module in the third stage or the LED module in the fourth stage in the same row as the first LED module). The second path A2 and the second path A3 are, for example, signal lines capable of transmitting a power supply control signal.The second path A2 and the second path A3 may be any path that can transmit a power supply control signal, and may be, for example, a pair of cables including a line representing HI or LOW and a ground line.

[0031] When turning off (stopping) the LED module 10-11 after activating it, a unique OFF command may be set in advance between the LED controller 4 and the signal processing unit 10c11, and this OFF command may be used. For example, when the signal processing unit 10c11 receives the OFF command from the LED controller 4, it generates a power supply control signal including an instruction to stop the power supply and transmits it to the power supply unit 10d2 of the downstream LED module 10-12 via the second path. As a result, in response to receiving the power supply control signal including an instruction to stop the power supply, the power supply unit 10d2 stops operating and also stops the power supply to the signal processing unit 10c2.

[0032] The second connecting line of the signal processing unit 10c11 is connected to the terminal 21t2. Terminals 21t2 and 21t3 are communicatively connected via a first path 21A2. That is, the first path connects the signal processing unit of the first LED module with the signal processing unit of the second LED module, and supplies signals including a video signal. The first path is, for example, a communication cable. For example, a LAN cable can be used as the communication cable. The first path 21A2 connects the signal processing unit 10c11 of the LED module 10-11 with the signal processing unit 10c2 of the LED module 10-21, and supplies at least one of a video signal and a startup signal to the signal processing unit 10c2. Furthermore, the first path 21A3 connects the signal processing unit 10c2 of the LED module 10-21 with the signal processing unit of the LED module 10-22, and supplies at least one of a video signal and a startup signal to the signal processing unit 10c2. In this way, the first path connects the signal processing units of adjacent LED modules 10 in each column and supplies various signals. Although the first path will be described as a path connecting a terminal of an LED module to a terminal of the LED module 10 in the next row after that LED module, it may also be a path connecting a signal processing unit of an LED module to the signal processing unit of the LED module 10 in the next row after that LED module. In this way, the first path connects the signal processing units of adjacent LED modules 10 in each column.

[0033] When the signal processing unit 10c11 receives the activation signal from the LED controller 4, it transmits the activation signal to the signal processing unit 10c2 of the subsequent LED module 10-21 via the first path 21A2.

[0034] Third connection line 10c11a of signal processing unit 10c11 is connected to display unit 10b1. When power is supplied from power supply unit 10d11, signal processing unit 10c11 supplies power to display unit 10b1 via connection line 10c11a.

[0035] The LED module 10-21 includes a power supply unit 10d2, a signal processing unit 10c2, and a display unit 10b2. The LED module 10-21 also has terminals 21t3, 22t3, 23t3, 21t4, 22t4, and 23t4.

[0036] Here, the LED module 10-21 has a supply path 22A21 that supplies a power control signal to a signal processing unit of a third LED module (e.g., LED module 10-31) connected in the next stage after the LED module 10-21. The supply path 22A21 is connected between the terminal 22t3 and the terminal 22t4, and supplies the power control signal to the second path 22A3.

[0037] FIG. 5 is a functional block diagram illustrating the function of power supply unit 10d11. Power supply unit 10d11 includes AC-DC conversion unit 10d11a and switch unit 10d11b. AC-DC conversion unit 10d11a converts externally supplied AC power into DC power and outputs it. Switch unit 10d11b receives a power control signal and switches whether or not to supply DC power to a subsequent stage (signal processing unit) depending on whether the power control signal is ON or OFF. For example, when the power control signal is ON, switch unit 10d11b switches ON to supply DC power output from AC-DC conversion unit 10d11a to the subsequent stage (signal processing unit). When the power control signal is OFF, switch unit 10d11b switches OFF to cut off power supplied from AC-DC conversion unit 10d11a to the subsequent stage (signal processing unit).

[0038] According to the configuration of power supply unit 10d11 in this figure, the power supplied from AC-DC conversion unit 10d11a to the signal processing unit can be cut off in response to the power supply control signal. This makes it possible to stop the power supplied to the signal processing unit and the display unit when LED module 10 is not being driven, thereby reducing the power consumption of the LED module.

[0039] FIG. 6 is a functional block diagram illustrating the function of power supply unit 10d11. Power supply unit 10d11 includes relay control circuit 10d11c and AC relay 10d11d. AC-DC conversion unit 10d11a converts externally supplied AC power into DC power and outputs it. Relay control circuit 10d11c drives the AC relay based on a relay control signal input from the outside. Relay control circuit 10d11c switches AC relay 10d11d ON or OFF depending on whether the relay control signal is ON or OFF, for example. For example, when the relay control signal is ON, relay control circuit 10d11c switches AC relay 10d11d ON to supply externally supplied AC power to AC-DC conversion unit 10d11a. When the relay control signal indicates OFF, relay control circuit 10d11c switches AC relay 10d11d to OFF, thereby cutting off AC power supplied from outside to AC-DC conversion unit 10d11a.

[0040] The AC relay is connected between the AC power source and AC-DC conversion unit 10d11a and switches between ON and OFF states in response to instructions from relay control circuit 10d11c. Here, the relay control signal can be a power supply control signal input from the signal processing unit of the preceding LED module 10. The configuration of power supply unit 10d11 in this figure allows power supplied to AC-DC conversion unit 10d11a to be cut off based on the relay control signal before the signal is input to AC-DC conversion unit 10d11a. In this case, when power is not supplied to the signal processing unit, the operation of AC-DC conversion unit 10d11a can be stopped, thereby reducing power consumption by AC-DC conversion unit 10d11a.

[0041] Furthermore, because AC relay 10d11d switches between interrupting and supplying power between the path through which AC power is supplied and AC-DC conversion unit 10d11a, there is no need to disconnect the third path through which AC power is supplied between the LED modules. As a result, while a circuit with a large current capacity would be required to interrupt power on the third path, a circuit with a small current capacity can be used because it is sufficient to interrupt power to AC-DC conversion unit 10d11a.

[0042] 7 is a functional block diagram showing the configuration of an LED module 10-21a, which is another configuration of the LED module 10-21 connected in the second or subsequent tier. Each of the LED modules in the second or subsequent tiers may have the configuration shown in the LED module 10-21a, or at least one of the LED modules in one row may have the configuration of the LED module 10-21a. The same components of the LED module 10-21a as those in the LED module 10-21 in FIG. 4 are designated by the same reference numerals, and their description will be omitted.

[0043] The LED module 10-21a includes a delay circuit 10e. The delay circuit 10e is connected between the terminal 22t3 and the power supply unit 10d2. The delay circuit 10e delays the timing at which the power control signal supplied from the first LED module (e.g., the LED module 10-11 in FIG. 4) reaches the power supply unit (the power supply unit 10d2 in this figure) of the second LED module (e.g., the LED module 10-21a).

[0044] Here, the LED module 10-21a has a supply path 22A21 that supplies a power control signal to a signal processing unit of a third LED module (e.g., LED module 10-31) connected in the next stage after the LED module 10-21a. The supply path 22A21 is connected between the terminals 22t3 and 22t4, and supplies the power control signal before being input to the delay circuit 10e or the power control signal after being delayed by the delay circuit 10e via the second path 22A3.

[0045] The delay time set in the delay circuit 10e can be set to any time. The delay circuit 10e can delay the timing at which the power supply control signal is input to the power supply unit from the timing at which the power supply unit is started based on the power supply control signal in the LED module connected in the preceding stage. This allows the power supply units of multiple LED modules in the same column to start up at different times, thereby reducing inrush current in the LED display device 1.

[0046] 8 is a diagram showing a specific example of the configuration of the delay circuit 10e in FIG. 7. The first terminal of the capacitor C1 is connected to the input terminal Tin, and the other terminal, the second terminal, is connected to the delay time setting unit TD. The capacitance of the capacitor C1 may be determined according to the delay time. The delay time setting unit TD sets the delay time. The delay time setting unit TD includes multiple resistors and multiple switches. For example, the delay time setting unit TD includes multiple setting units Ut, each of which is configured by connecting one resistor Rt and one switch SWt in series. The multiple setting units Ut are connected in parallel between the second terminal of the capacitor C1 and a connection point connected to ground.

[0047] The resistance values ​​of the multiple resistors Rt may be different or may be the same. The multiple switches SWt are physical switches that can be switched on and off in response to an operator's operation. This allows the delay time to be set in accordance with the combination of the on / off state of each of the multiple switches SWt and the resistance value of the resistor Rt connected to the switch that is turned on.

[0048] A first terminal of the resistor R11 is connected to the input terminal Tin, and the other terminal, a second terminal, is connected to a first terminal of the resistor R12. A first terminal of the resistor R12 is connected to the second terminal of the resistor R11, and the other terminal, a second terminal, is connected to ground. When a power supply control signal is applied to the terminal Tin, the voltage at the connection point between the resistors R11 and R12 is maintained at a substantially constant value. The voltage applied to the second input terminal of the operational amplifier OP can be set according to the combination of the resistance values ​​of the resistors R11 and R12.

[0049] The first input terminal of the operational amplifier OP is connected to the connection point between the capacitor C1 and the delay time setting unit TD. The second input terminal of the operational amplifier OP is connected to the connection point between the resistors R11 and R12. The positive power supply terminal of the operational amplifier is connected to the input terminal Tin, and the negative power supply terminal is connected to ground. The operational amplifier OP compares the voltage input from the first input terminal with the voltage input from the second input terminal, and outputs a power supply control signal from the output terminal if the voltage input from the first input terminal is higher than the voltage input from the second input terminal. The operational amplifier OP does not output a power supply control signal from the output terminal if the voltage input from the first input terminal is equal to or lower than the voltage input from the second input terminal.

[0050] For example, when a power supply control signal is input to the delay circuit 10e, the voltage at the connection point between the capacitor C1 and the delay time setting unit TD rises according to the combined resistance set in the delay time setting unit TD and the capacitance of the capacitor C1. When the voltage at the connection point between the capacitor C1 and the delay time setting unit TD exceeds the voltage at the connection point between the resistors R11 and R12, the operational amplifier OP connects the power supply control signal to the outside. Here, the time from when the power supply control signal is supplied to the terminal Tin to when it is output from the terminal Tout can be changed according to the on / off state of each of the multiple switches SWt.

[0051] Here, a specific delay time can be set for each LED module provided with the delay circuit 10e depending on the combination of on / off states of the multiple switches SWt in the delay time setting unit TD. By setting different delay times for the delay time setting units TD for the multiple LED modules, the power supply units of each LED module can be started at different times. If the power supply units of each LED module were started at the same time, an inrush current would be more likely to occur in the LED display device 1 when power is supplied to the LED display device 1. However, according to this embodiment, even when power is supplied to the LED display device 1, the power supply units of each LED module start at different times, which allows the timing at which the inrush current occurs in each LED module to be shifted, thereby reducing the inrush current generated throughout the entire LED display device 1.

[0052] 9 is a functional block diagram showing a schematic configuration of the signal processing unit 10c11 in FIG. 4. In the signal processing unit 10c11, the first connector 101 is a receptacle into which, for example, an RJ-45 connector can be inserted. A communication cable 21A1 is connected to the first connector 101. The pulse transformer 102 is connected to the first connector 101 and also to a PHY (Ethernet Physical Layer Transceiver) device 103. The pulse transformer 102 has a primary winding and a secondary winding, and inputs various signals (startup signal, video signal, etc.) from the outside (LED controller 4) via the first connector 101. The pulse transformer 102 supplies various signals to the PHY device 103 via the primary winding and secondary winding. The pulse transformer 102 outputs various signals to the subsequent stage via the primary winding and secondary winding, thereby blocking the intrusion of high voltages and the like input from the first connector 101 and protecting the device from transmission of high voltages and the like inside.

[0053] The PHY device 103 is connected to the pulse transformer 102, a CPU (Central Processing Unit) 104, a PHY device 106, and an EtherMAC (Media Access Controller) 107. The PHY device 103 receives Ethernet signals via the pulse transformer. These Ethernet signals include various types of signals, such as a wake-up signal and a video signal. The PHY device 103 converts the analog signals supplied from the pulse transformer 102 into digital signals and outputs them to the CPU 104, the PHY device 106, and the EtherMAC 107. The PHY device 103 has a circuit that detects whether a wake-up signal (e.g., a WOL command) is included in the various signals input from the pulse transformer 102. When the PHY device 103 detects a wake-up signal (e.g., a WOL command), it generates an interrupt signal and outputs the generated interrupt signal to the CPU 104. The PHY device 103 outputs to the EtherMAC 107, among the video signals contained in the Ethernet signal, the video signals to be displayed on the LED module in which the PHY device 103 is installed, and supplies to the PHY device 106 the video signals that are not to be displayed on the LED module in which the PHY device 103 is installed (video signals to be displayed on the subsequent LED module 10).

[0054] The CPU 104 is connected to the PHY device 103, the buffer circuit 105, and the video and control data signal processing unit 108. When the CPU 104 receives an interrupt signal based on a startup signal (e.g., a WOL command) from the PHY device 103, it determines that a startup instruction has been received from the LED controller 4, generates a power control signal, and outputs the generated power control signal to the buffer circuit 105. The CPU 104 also receives an OFF command from the video and control data signal processing unit 108. Upon receiving the OFF command, the CPU 104 outputs a power control signal to the buffer circuit 105 to turn off the power. The buffer circuit 105 is connected to the CPU 104 and a terminal 22t2. The terminal 22t2 is connected to the second path 22A2. This allows the buffer circuit 105 to transmit the power control signal to the LED module connected in the next stage via the second path 22A2.

[0055] Here, when a startup signal is not input, the PHY device 103 and CPU 104 wait for a startup signal while being activated by power supplied from the power supply unit in order to detect whether a startup signal is input and generate a power control signal.

[0056] The PHY device 106 is connected to the PHY device 103 and the pulse transformer 109. The PHY device 106 outputs the video signal supplied from the PHY device 103 to the pulse transformer 109.

[0057] The pulse transformer 109 is connected to the PHY device 106 and the second connector 110. The pulse transformer 109 has a primary winding and a secondary winding, and supplies a video signal input from the PHY device 106 to the second connector 110 via the primary winding and the secondary winding. The pulse transformer 109 outputs the video signal to a subsequent stage via the primary winding and the secondary winding, thereby preventing transmission of high voltage or the like to the subsequent stage. The second connector 110 is connected to the pulse transformer 109 and the terminal 21t2. The terminal 21t2 is connected to the first path 21A2. This allows the second connector 110 to transmit the video signal to the LED module connected to the next stage via the first path 21A2.

[0058] The EtherMAC 107 is connected to the PHY device 103 and the video and control data signal processing unit 108. The EtherMAC 107 acquires, from the PHY device 103, a video signal to be displayed on the LED module in which the EtherMAC 107 is provided, and supplies the video and control data signal processing unit 108.

[0059] Video and control data signal processing unit 108 is connected to EtherMAC 107, CPU 104, and the display unit. Video and control data signal processing unit 108 drives the LEDs of the display unit based on the video signal supplied from EtherMAC 107, thereby displaying a video based on the video signal on display unit 10b1. If the video signal supplied from EtherMAC 107 includes an OFF command, video and control data signal processing unit 108 supplies an OFF command to CPU 104. Furthermore, if the video signal supplied from EtherMAC 107 includes an OFF command, video and control data signal processing unit 108 prevents the video based on the video signal on display unit 10b1 from being displayed.

[0060] Here, a case will be described in which a WOL command is used as the wake-up signal, but the wake-up signal may be an ON command instead of a WOL command. In this case, if the WOL command is not detected in PHY device 103 but video / control data signal processing unit 108 detects that the video signal supplied from EtherMAC 107 includes an ON command, it supplies the ON command to CPU 104. As a result, CPU 104 generates a power control signal based on the ON command. Furthermore, if video / control data signal processing unit 108 detects the video signal supplied from EtherMAC 107, it causes display unit 10b1 to display an image based on the video signal.

[0061] In the above-described embodiment, the signal processing unit 10c11 shown in FIG. 9 has been described as waiting for a startup signal while the PHY device 103 and CPU 104 are activated by power supplied from the power supply unit. FIG. 10 is a functional block diagram showing a schematic configuration of a signal processing unit 10c11-1, which is another configuration of the signal processing unit 10c11 described above. In the signal processing unit 10c11-1, components similar to those of the signal processing unit 10c11 are designated by the same reference numerals, and their description will be omitted. The standby power supply unit 115 is connected to the power supply unit 10d11 and the PHY device 103a, and supplies power supplied from the power supply unit 10d11 to the PHY device 103a. The standby power supply unit 115 supplies standby power, which is power sufficient to maintain a standby state, to the PHY device 103a and the CPU 104a.

[0062] The PHY device 103a is connected to the standby power supply unit 115, the pulse transformer 102, the PHY device 106, the EtherMAC 107, and the CPU 104a. The PHY device 103a receives standby power from the standby power supply unit 115 and operates until a wake-up signal is input from the LED controller 4, and has a detection unit that detects whether the wake-up signal has been input. The PHY device 103a transitions to a standby state until a wake-up signal is input from the LED controller 4. If a wake-up signal is not input, the PHY device 103a does not output a signal indicating that a wake-up signal has been input to the CPU 104a. On the other hand, if the PHY device 103a detects that a wake-up signal has been input, it outputs a signal indicating that a wake-up signal has been detected to the CPU 104 and transitions to a normal state.

[0063] CPU 104a is connected to PHY device 103a, buffer circuit 105, video / control data signal processing unit 108, and main power supply unit 116. CPU 104a has a control unit that is driven by power supplied from standby power supply unit 115. The control unit stops driving power supply unit 10d11 until a wake-up signal is detected by PHY device 103a, and drives power supply unit 10d11 when it detects that the wake-up signal has been supplied by PHY device 103a. When the wake-up signal is not detected by PHY device 103a, CPU 104a stops main power supply unit 116 and transitions to a standby state. When CPU 104a receives a signal from PHY device 103a indicating that the wake-up signal has been detected, it starts main power supply unit 116 and transitions to a normal state. Furthermore, when a startup signal is not input (or an OFF command is input), the CPU 104a operates in a standby state by receiving power from the PHY device 103a or the standby power supply unit 115. Here, the PHY device 103a supplies the power supplied from the standby power supply unit 115 to the CPU 104a. However, if the CPU 104a can receive power directly from the standby power supply unit 115, the PHY device 103a does not need to supply power to the CPU 104a.

[0064] Main power supply unit 116 is connected to power supply unit 10d11, CPU 104a, and signal processing unit 10c11-1. Main power supply unit 116 can switch whether or not to supply power to signal processing unit 10c11-1 based on an instruction from CPU 104a. When an instruction to supply power is input from CPU 104a, main power supply unit 116 supplies power from power supply unit 10d11 to signal processing unit 10c11-1. This causes the entire signal processing unit 10c11-1 to transition to a drivable state.

[0065] Here, when a wake-up signal is not input to signal processing unit 10c11-1, power sufficient to maintain the standby state is supplied from standby power supply unit 115 to PHY device 103a. As a result, PHY 103a and CPU 104a transition to the standby state until a wake-up signal is detected. As a result, until a wake-up signal is detected, signal processing unit 10c11-1 as a whole is not started, and only power sufficient to operate PHY 103a and CPU 104a is supplied, thereby enabling power saving for the LED module at the head of the column of LED display device 1 (the LED module connected to LED controller 4).

[0066] According to this embodiment, by dividing the power supply between the standby power supply unit 115 and the main power supply unit 116, the CPU 104a can stop the main power supply and limit the power supply to other circuits until the PHY 103a detects a wake-up signal (such as a WOL command), thereby achieving power saving.

[0067] Next, an example of a configuration in which the signal processing unit 10c11 outputs a power supply control signal to an adjacent LED module 10 will be described. FIG. 11 is a schematic functional block diagram illustrating a configuration for outputting a power supply control signal. In this diagram, the configuration around the CPU 104 of the signal processing unit 10c11 in FIG. 9 is described, but other configuration such as the PHY device 103 is not illustrated. The LED module 10-11 shown in this diagram has a configuration that can be applied to the LED module 10 in the first row of each column. The buffer circuit 105 of the LED module 10-11 is connected to the CPU 104 and the switch 122. The buffer circuit 105 reduces the output impedance of the power supply control signal supplied from the CPU 104 and supplies it to the switch 122.

[0068] The power supply control signal input terminal 121 is connected to a first input terminal of the switch 122 and can be connected to a supply path of a power supply control signal supplied from outside. The power supply control signal input terminal 121 of the LED module 10-11 is not connected to the supply path of the power supply control signal.

[0069] The switch 122 of the LED module 10-11 has a first input terminal connected to the power control signal input terminal 121 and a second input terminal connected to the output terminal of the buffer circuit 105, and is connected to either the first or second input terminal. The output of the switch 122 is connected to the vertical output terminal 123 and the horizontal output terminal 124. As a result, the switch 122 supplies the power control signal supplied via the selected terminal of the first or second input terminal to the vertical output terminal 123 and the horizontal output terminal 124, respectively. Whether the switch 122 is connected to the first or second input terminal can be manually selected using a physical switch.

[0070] The switch 122 supplies a signal input from a selected terminal of the first input terminal and the second input terminal to the vertical output terminal 123 and the horizontal output terminal 124. The switch 122 of the LED module in the first stage of the column is set to be connected to the second input terminal (buffer circuit 105). The switches 122 of the LED modules in the second stage and subsequent stages of each column are set to be connected to the power supply control signal input terminal. Note that nothing is connected to the power supply control signal input terminal 121 of the LED modules 10-11.

[0071] The vertical output terminal 123 is connected to the power supply control signal input terminal 121 of the LED module 10-21 in the next row in the same column via a second path 22A2. That is, the vertical output terminal 123 can be connected to the signal processing unit of the LED module arranged in the subsequent row in the column direction via the second path.

[0072] As a result, the power control signal supplied from the buffer circuit 105 of the LED module 10-11 is supplied to the switch 122 of the LED module 10-21 via the second path 22A2 connected to the vertical output terminal 123 and the power control signal input terminal 121 of the LED module 10-21. Therefore, the configuration of the signal processing unit of the LED module 10-11 provided in the first stage and the LED modules provided in the second stage and thereafter (LED module 10-21, LED module 10-31, etc.) can be made common, and by switching the switch 122, it is possible to select the supply path of the power control signal for each of the LED modules in the first stage and the second stage and thereafter (LED module 10-21, LED module 10-31, etc.).

[0073] The horizontal output terminal 124 is a terminal that can be connected via a fourth path 24A1 to the power supply control signal input terminal 121 of the LED module 10-12 arranged in the same row in the row direction and in an adjacent column (here, as an example, the right side).

[0074] The second input terminal of switch 122 of signal processing unit 10c12 is connected to the output of buffer circuit 105 of LED module 10-11. Here, switch 122 of signal processing unit 10c12 is selected to be connected to the first input terminal, and is therefore selected to be able to input the power control signal supplied from signal processing unit 10c11, which is provided adjacently on the left. Therefore, switch 122 supplies the power control signal to vertical output terminal 123 and horizontal output terminal 124 of signal processing unit 10c12. Horizontal output terminal 124 of signal processing unit 10c12 is connected to the power control signal input terminal of LED module 13, which is adjacent on the right. As a result, the power control signal is supplied to the first-stage LED module in the adjacent column.

[0075] The power supply control signal input terminal 121 of the LED module 10-12 is connected to the horizontal output terminal 124 of the adjacent LED module 10-11 on the left side via a second path, and is also connected to the first input terminal of the switch 122. The switch 122 of the LED module 10-12 is switched to connect to the power supply control signal input terminal 121 side. Thereafter, the LED module adjacent to the right side among the first-stage LED modules in each column is similarly connected, and the switch 122 is switched to the power supply control signal input terminal 121 side. Note that the horizontal output terminal 124 of the LED module located at the rightmost side of the LED display device 1 is not connected to the next LED module because there is no LED module connected to the right side.

[0076] The vertical output terminal 123 of the LED module 10-21 is connected to the signal processing unit of the LED module in the next row, but the horizontal output terminal 124 is not connected to the adjacent LED module on the right. In other words, the horizontal output terminal 124 of the LED modules in rows after the second row is not connected to the adjacent LED module on the right. Furthermore, the vertical output terminal 123 of the LED module in the last row in each column is not connected to the LED module in the next row because there is no LED module in the next row.

[0077] In order to protect the buffer circuit 105, when the buffer circuit 105 and the switch 122 are connected, the connection may be made via a current protection circuit. A simpler solution would be a resettable fuse (a PTC (Positive Temperature Coefficient) thermistor using a conductive polymer).

[0078] According to this embodiment, by setting the signal path after the buffer circuit 105 in advance using the switch 122, it is possible to switch between receiving a power control signal from an LED module connected to the previous stage (or previous row) or from the CPU of the LED module itself. This allows the power control signal output from the CPU 104 of a certain LED module to be used not only in the LED module itself, but also to be supplied to other LED modules. This allows the configurations of the first stage and the second stage and subsequent stages to be standardized. Furthermore, because the CPUs 104 of the LED modules in the second stage and subsequent stages do not need to generate power control signals, power consumption can be reduced.

[0079] According to this embodiment, the LED module 10-11 and the LED module 10-21 are arranged adjacent to each other, and the LED module 10-12, which is the next stage in a different series from the LED module 10-21, is arranged adjacent to the LED module 10-11. The LED module 10-11 is further provided with a fourth path 24A1 that is connected to the power supply unit of the LED module 10-12 and that supplies a power control signal that causes the power supply unit of the LED module 10-12 to supply power to the signal processing unit of the LED module 10-12. By providing the fourth path 24A1, the power control signal can be supplied to an LED module in a subsequent stage in the column to which the LED module generating the power control signal belongs, and the power control signal can also be supplied to an LED module in a column adjacent to the LED module generating the power control signal. This eliminates the need to provide one LED module per column that generates a power control signal.

[0080] In this embodiment, the case where LED module 10-11 is connected to two LED modules, one above it in the column direction and one to the right in the row direction, has been described, but three or more LED modules may be connected to one LED module. For example, one LED module may be connected to three or four LED modules, including the LED modules above and below it in the column direction and the LED modules to the right and left in the row direction. In this case, the vertical output terminal 123 and the horizontal output terminal 124 may be increased according to the number of LED modules to be connected.

[0081] Next, another example of a configuration in which the LED module 10-11 outputs a power supply control signal to an adjacent LED module 10 will be described. Fig. 12 is a schematic functional block diagram illustrating another example of a configuration in which the LED module 10-11 outputs a power supply control signal. In this figure, another example of the peripheral configuration of the CPU 104 of the LED module 10-11 in Fig. 9 will be described, but other components such as the PHY device 103 will not be illustrated. Furthermore, components similar to those in Fig. 11 will be assigned the same reference numerals, and their description will be omitted.

[0082] In the LED module 10-11-2, the input terminal of the diode 141 is connected to the power supply Vcc of the signal processing unit 10c-2, and the output terminal is connected to the connection point 142. The positive power supply terminal of the buffer circuit 105 is connected to the connection point 142. The buffer circuit 105 can be driven by power supplied from the power supply Vcc. The side power supply terminal 125 is connected to the connection point 142 and is also connected to the connection point 142 of the signal processing unit 10c12-2 of the LED module adjacent to the right. The switch 132 is connected between the CPU 104 and the buffer circuit 105. More specifically, the first input terminal of the switch 132 is connected to the power control signal input terminal 131, and the second input terminal is connected to the output terminal of the CPU 104. The output terminal of the switch 132 is connected to the input terminal of the buffer circuit 105. Whether the switch 132 is connected to the first input terminal or the second input terminal can be manually selected using a physical switch. The switch 132 of the signal processing unit 10c11-2 is switched to connect to the second input terminal.

[0083] Power supply control signal input terminal 131 of LED module 10-12-2 is connected to horizontal output terminal 124 of signal processing unit 10c11-2 via second path 25A1. Switch 132 of signal processing unit 10c12-2 is switched to connect to the first input terminal.

[0084] Furthermore, the positive power supply terminal of the buffer circuit 105 of the LED module 10-12-2 is connected to the connection point 142 of the LED module 10-12-2. The buffer circuit 105 of the LED module 10-12-2 can be driven by receiving a voltage supplied from the connection point 142, and supplies a power supply control signal input via the power supply control signal input terminal 131 and the lateral output terminal 124 of the adjacent LED module 10-11-2 to the second input terminal of the switch 122 connected in the subsequent stage. This allows the LED module 10-12-2 to obtain the power supply control signal from the adjacent LED module 10-11-2 without having to generate it using the CPU 104 provided in the LED module 10-12-2.

[0085] Furthermore, according to this embodiment, when the input impedance of the LED modules connected to the vertical output terminal 123 and the horizontal output terminal 124 is low, it is possible to configure the LED module 10-11-2 (the LED module provided in the first stage of the row) to supply power to the buffer circuit 105 of the next LED module (the LED module connected in the latter stage of the row, the adjacent LED module connected to the right).

[0086] Here, depending on the impedance, an LED module adjacent to an LED module whose power supply unit is activated may not be able to operate with just the control signal supplied from the buffer of the previous stage (or the adjacent LED module in the horizontal direction) even when the power supply unit is off. Even in such a case, the power supplied to the previous stage (or the adjacent LED module in the horizontal direction) can be supplied to drive the next stage (or the adjacent LED module in the horizontal direction). Here, power can be supplied to the adjacent LED module via the side power supply terminal 125.

[0087] In addition, the standby power of the signal processing unit described in this embodiment can be supplied from another LED module, and activation by an orbit signal (WOL command, etc.) can be performed for each column, making it possible to configure the LED display to reduce power consumption as a whole. Also, with this configuration, in order to prevent current leakage to circuits other than the buffer circuit 105, power can be supplied from the power supply Vcc via a diode 141.

[0088] Next, Fig. 13 is a schematic functional block diagram showing another configuration of the LED module 10. In this figure, other configuration examples of the LED module 10-11 and the LED module 10-21 in Fig. 4 will be described. In addition, in the LED module 10-11b, components similar to those of the LED module 10-11 in Fig. 4 are assigned the same reference numerals, and their description will be omitted. In addition, in the LED module 10-21b, components similar to those of the LED module 10-21 in Fig. 4 are assigned the same reference numerals, and their description will be omitted.

[0089] LED module 10-11b has power supply unit 10d11-2, signal processing unit 10c11-2, power supply cutoff circuit 10f11, and display unit 10b1. LED module 10-11b also has terminals 21t2, 22t2, and 23t2. Power supply unit 10d11-2 converts AC power supplied from an external source into DC power and outputs it to signal processing unit 10c11-2. Here, power supply unit 10d11-2 does not have a circuit that turns on and off based on a power supply control signal, such as switch unit 10d11b shown in FIG. 6 or AC relay d11d or relay control circuit 10d11c shown in FIG. 7.

[0090] The signal processing unit 10c11-2 has the functions of the signal processing unit 10c11-1, standby power supply unit 115, and main power supply unit 116 shown in FIG. 10. When the signal processing unit 10c11-2 receives a Wake-on-LAN packet (start-up signal) from the LED controller 4, it transitions the PHY device (103) and CPU (104) within the signal processing unit 10c11-2 from standby state to normal state. When the signal processing unit 10c11-2 transitions to the normal state, it generates a power control signal, turns on the power supply cut-off circuit 10f11, and causes the power supply cut-off circuit 10f11 to supply power to the display unit 10b1. Furthermore, when the signal processing unit 10c11-2 generates the power control signal, it supplies the power control signal to the signal processing unit 10c21-2 of the LED module 10-21b in the next row in the same column via the second path 22A2, and also supplies the power control signal to the power supply cut-off circuit 10f11. When transitioning from the normal state to the standby state, a unique OFF command is set in advance between the LED controller 4 and the signal processing unit 10c11-2, and the signal processing unit 10c11-2 transitions to the standby state by acquiring this OFF command from the LED controller 4. When the signal processing unit 10c11-2 receives the OFF command from the LED controller, it generates a power control signal for turning off the power and outputs it to the power supply cut-off circuit 10f11. As a result, the power supply cut-off circuit 10f11 turns off the power and stops the power supply to the display unit 10b1. Furthermore, when the signal processing unit 10c11-2 receives the OFF command from the LED controller, it transitions the PHY (103) and CPU (104) from the normal state to the standby state.

[0091] LED module 10-21b includes power supply unit 10d21-2, signal processing unit 10c21-2, power supply cutoff circuit 10f21, and display unit 10b2. LED module 10-21b also includes terminals 21t3, 22t3, 23t3, 21t4, 22t4, and 23t4. Power supply unit 10d21-2 converts AC power supplied from an external source into DC power and outputs it to signal processing unit 10c21-2. Power supply unit 10d21-2 does not include a circuit that turns on and off based on a power supply control signal, such as switch unit 10d11b shown in FIG. 6 or AC relay d11d or relay control circuit 10d11c shown in FIG. 7.

[0092] When the signal processing unit 10c21-2 receives a power control signal from the LED module 10-11b connected in the previous stage in the same column, it transitions the PHY (103) and CPU (104) from standby state to normal state. Here, an LED module (e.g., LED module 10-21b) connected in a stage subsequent to the first-stage LED module (e.g., LED module 10-11b) connected to the LED controller 4 cannot receive a Wake-on-LAN packet (wake-up signal) because the first-stage LED module is in standby state. When the signal processing unit 10c21-2 receives a wake-up signal from the LED module connected in the previous stage, it transitions the PHY device (103) and CPU (104) in the signal processing unit 10c11-2 from standby state to normal state. When signal processing unit 10c21-2 transitions from the standby state to the normal state, it generates a power supply control signal, turns on power supply cutoff circuit 10f21, and causes power supply cutoff circuit 10f21 to supply power to display unit 20b1. Furthermore, when signal processing unit 10c21-2 generates the power supply control signal, it supplies the power supply control signal to the signal processing unit of the next LED module in the same column via second path 22A3, and also supplies the power supply control signal to power supply cutoff circuit 10f21. When transitioning from the normal state to the standby state, signal processing unit 10c21-2 transitions to the standby state by receiving the above-mentioned OFF command from signal processing unit 10c11-2. Furthermore, signal processing unit 10c21-2 may transition to the standby state by receiving a power supply control signal for turning off the power from signal processing unit 10c11-2. When the signal processing unit 10c21-2 receives an OFF command from the LED controller or a power control signal from the preceding LED module, it generates a power control signal for turning off the power and outputs it to the power supply cutoff circuit 10f21. As a result, the power supply cutoff circuit 10f21 turns off the power and stops the power supply to the display unit 10b2. Furthermore, when the signal processing unit 10c21-2 receives an OFF command or a power control signal for turning off the power from the preceding LED module, it transitions the PHY (103) and CPU (104) from the normal state to the standby state.

[0093] Fig. 14 is a diagram showing an example of calculation of how much power is reduced in the above-mentioned LED display device. In this example, the following relationship between the configuration of one LED module and power consumption is taken as an example: (Example a) Power consumption when one LED module displays all black in a conventional LED module: 20 W (Example b) Power consumption when the DC output of an LED module having the power supply unit shown in Fig. 5 is turned off: 2 W (Example c) Power consumption when the AC relay of an LED module having the power supply unit shown in Fig. 6 is turned off: 0.3 W (Example d) Power consumption when the AC relay of an LED module having the power supply unit shown in Fig. 6 is turned off and the signal processing unit shown in Fig. 10 is applied: 0.5 W

[0094] Here, calculations were performed for a case where an LED display device was constructed using multiple LED modules from any of the above examples a to d, with four different arrangements: 4x4, 5x5, 6x6, and 8x8. The 4x4 arrangement was performed with four LED modules arranged vertically and four horizontally, for a total of 16 LED modules. Similarly, the 5x5 arrangement was performed with five LED modules arranged vertically and five horizontally, for a total of 25 LED modules. The 6x6 arrangement was performed with six LED modules arranged vertically and six horizontally, for a total of 36 LED modules. The 8x8 arrangement was performed with eight LED modules arranged vertically and eight horizontally, for a total of 64 LED modules.

[0095] (Example a) When power is supplied from the distribution board, all LED modules enter an active state. Here, even if no video is being supplied based on a video signal, power is consumed to display the entire screen in black. The total power consumption for a 4x4 layout is 320W, and the more LED modules are arranged, the greater the power consumption. For an 8x8 layout, the total power consumption is 1280W.

[0096] (Regarding Example b) When power is supplied from the distribution board and no video signal is supplied, one LED module operates normally, but the other LED modules stop DC output from the power supply. The total power consumption for the 4x4 configuration is 50W, and the total power consumption for the 8x8 configuration is 146W. Therefore, compared to Example 1, the reduced power consumption for the 8x8 configuration is 1134W.

[0097] (Example c) When power is supplied from the distribution board and no video signal is supplied, one LED module operates normally, but the AC relays in the power supply unit for the other LED modules are turned off. The total power consumption for the 4x4 configuration is 24.5 W, and the total power consumption for the 8x8 configuration is 38.9 W. Therefore, compared to Example 1, the reduced power consumption for the 8x8 configuration is 1241.1 W.

[0098] (Regarding Example d) When power is supplied from the distribution board but no video signal is supplied, one LED module operates in standby mode, while the AC relays in the power supply unit for the other LED modules are turned off. The total power consumption for the 4x4 configuration is 5W, and the total power consumption for the 8x8 configuration is 19.4W. Therefore, compared to Example 1, the reduced power consumption for the 8x8 configuration is 1260.6W.

[0099] As described above, the configuration of this embodiment can reduce power consumption compared to the conventional configuration. Furthermore, the more LED modules are arranged, the greater the reduction in power consumption becomes.

[0100] In conventional LED display devices, the AC power supplies for the LED modules arranged in columns are connected in series to a power distribution board. When AC power is supplied, various circuits within the LED modules operate and consume power, even when no video is being displayed. Because an LED display device includes multiple LED modules, the power consumption of the entire LED display device increases as the number of LED modules increases, which cannot be ignored. In contrast, according to the above-described embodiment, one LED module generates a power control signal based on an activation signal received from an LED controller and supplies it to the other LED modules. As a result, the other LED modules simply transition from standby to normal mode upon receiving this power control signal. Therefore, when no video signal is being displayed, the other LED modules can transition to standby mode instead of normal mode, thereby reducing power consumption. When the LED module is in standby mode, the signal processing unit cuts off the power supply to the display unit. This prevents power from being supplied to the display unit even when the power supply unit is activated, thereby reducing power consumption. Furthermore, by deactivating the power supply unit, power consumption can be further reduced. In this way, in addition to the path (first path) for supplying a video signal and the path (third path) for supplying AC power, a path (second path) for supplying a power supply control signal is provided, and the function of each LED module is activated or deactivated based on this power supply control signal, thereby reducing power consumption.

[0101] Furthermore, because conventional LED display devices are configured with multiple LED modules, a large inrush current occurs when the power supplies of the LED modules are turned on simultaneously. In contrast, according to the above-described embodiment, a delay circuit is provided in each LED module, so that the LED module does not start up immediately after receiving a power control signal from the previous LED module, but rather starts up after a set delay time has elapsed. This allows the start-up timing to be different from that of the previous LED module, thereby reducing the inrush current.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 1...LED display device, 2...distribution board, 3...video signal supply device, 4...LED controller, 10, 10-11, 10-11-2, 10-11b, 10-12, 10-12-2, 10-13, 10-14, 10-15, 10-16, 10-21, 10-21a, 10-21b, 10-22, 10-31, 10-41, 10-51, 10-61...LED module, 10-13G, 10-14G...module group, 10a...LED board, 10b, 10b1, 10b2...display unit, 20b1...display unit, 10c11a, 10d1a...connecting line, 10c12, 10c12-2, 10c2, 10c21, 10c21-2...signal processing unit, 10d, 10d1, 10d11, 10d11-2, 10d2, 10d21, 10d21-2...power supply unit, 10d1-1...ON signal supply unit, 10d11a...AC-DC conversion unit, 10d11b...switch unit, 10d11c...relay control circuit, 10d11d...AC relay, 10e...delay circuit, 10ele...LED element, 1 0f11, 10f21...power supply cutoff circuit, 10mod...signal processing module, 13...LED module, 21A1, 21B1...communication cable, 21, 22, 23A, 23A1...power line, 21A2, 21A3...first path, 21t1, 21t2, 21t3, 21t4, 22t2, 22t3, 22t4, 23t1, 23t2, 23t3, 23t4...terminal, 22A2, 22A3, 25A1...second path, 22A21...supply path, 23A2, 23A3...third path, 24A1...third Four paths, 101...first connector, 102, 109...pulse transformer, 103, 103a, 106...PHY device, 105...buffer circuit, 108...video and control data signal processing section, 110...second connector, 115...standby power supply section, 116...main power supply section, 121, 131...power control signal input terminal, 122, 132...switch, 123...vertical output terminal, 124...horizontal output terminal, 125...horizontal power supply terminal, 141...diode, 142...connection point, S...display system

Claims

1. An LED display device in which a plurality of LED modules are arranged, each of which includes 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 power supply unit that supplies power supplied from the outside to at least the signal processing unit, wherein a first LED module among the plurality of LED modules and a second LED module connected to the first LED module have: a first path that connects the signal processing unit of the first LED module to the signal processing unit of the second LED module and supplies a signal including a video signal; a second path that connects the signal processing unit of the first LED module to the power supply unit of the second LED module and supplies a power control signal for supplying power from the power supply unit of the second LED module to the signal processing unit of the second LED module; and a third path that connects the power supply unit of the first LED module to the power supply unit of the second LED module and supplies power supplied from the outside to the first LED module to the power supply unit of the second LED module.

2. The LED display device according to claim 1, wherein the signal processing unit of the first LED module generates the power supply control signal upon receiving a start signal from the external device and supplies the power supply control signal via the second path.

3. The LED display device according to claim 2, wherein the second LED module has a delay circuit that delays the timing at which the power control signal supplied from the first LED module reaches the power supply unit of the second LED module.

4. The LED display device described in claim 3, wherein the second LED module has a supply path for supplying the power supply control signal to a signal processing unit of a third LED module connected in the next stage of the second LED module, and the supply path supplies the power supply control signal before being input to the delay circuit or the power supply control signal after being delayed by the delay circuit.

5. An LED display device as described in claim 4, wherein the first LED module is supplied with standby power capable of maintaining a standby state from the power supply unit to the signal processing unit, and the signal processing unit has: a detection unit driven by the standby power and detecting whether or not a startup signal has been supplied from the external device; and a control unit driven by the standby power and stopping the operation of the power supply unit of the first LED module until a startup signal is detected by the detection unit, and driving the power supply unit of the first LED module when the detection unit detects that a startup signal has been supplied.

6. An LED display device as described in claim 1, wherein the first LED module and the second LED module are arranged adjacent to each other, a fourth LED module which is a next stage in a series different from the second LED module is arranged adjacent to the first LED module, and the signal processing unit of the first LED module further has a fourth path which is connected to a power supply unit of the fourth LED module and supplies a power supply control signal for supplying power from the power supply unit of the fourth LED module to the signal processing unit of the fourth LED module.

7. The LED display device described in claim 6, wherein the first LED module has a first terminal capable of connecting the second path to the second LED module and a second terminal capable of connecting a fourth path to the fourth LED module, and the power supply control signal is supplied to the second LED module and the fourth LED module by the signal processing unit of the first LED module being supplied to the first terminal and the second terminal.

8. The LED display device according to claim 7, wherein the plurality of LED modules each have a switch connected between a signal processing unit of the LED module itself and the first terminal and the second terminal connectable to an LED module in a subsequent stage, which selects either a power supply control signal output from the signal processing unit or a power supply control signal supplied from an LED module connected in a preceding stage, and supplies the selected power supply control signal to the first terminal and the second terminal.

9. The LED display device according to claim 1, wherein the second path is connected to the signal processing unit of the first LED module and any one of the LED modules in the next stage or later of the first LED module, and supplies a power supply control signal for supplying power from the power supply unit of a target LED module among any one of the LED modules in the next stage or later to the signal processing unit of the target LED module.

10. In an LED display device in which a plurality of LED modules are arranged, each of 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 a video signal supplied from an external device, and a power supply unit that supplies power supplied from the outside to at least the signal processing unit, a method for connecting a first LED module among the plurality of LED modules to a second LED module that is connected in the next stage to the first LED module, comprising the steps of: connecting the signal processing unit of the first LED module to the signal processing unit of the second LED module by a first path, and supplying a signal including a video signal via the first path; connecting the signal processing unit of the first LED module to a power supply unit of the second LED module by a second path, and supplying a power supply control signal for supplying power from the power supply unit of the second LED module to the signal processing unit of the second LED module via the second path; connecting the power supply unit of the first LED module to a power supply unit of the second LED module by a third path, and supplying power supplied from the outside to the power supply unit of the first LED module to the power supply unit of the second LED module via the third path.

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