Patent Grant
8766880
The present application is related to copending patent applications U.S. Ser. No. 12/001,277 entitled “Data And Power Distribution System and Method For A Large Scale Display System;” U.S. Ser. No. 12/001,276 entitled “Large Scale LED Display System;” and U.S. Ser. No. 12/001,315 entitled “Large Scale LED Display,” each filed concurrently herewith.
N/A
The present invention is directed to a large scale LED display and more particularly to an enumeration system and method for a large scale LED display that allows a pixel module to dynamically determine its location in a display.
LED displays are known that are formed of a number of LED modules wherein each LED module is used for one pixel of the display. Each of the LED modules has a number of different color LEDs, the intensities of which are controlled to generate pixels of a large number of different colors. Examples of these known types of LED displays are shown in Phares U.S. Pat. No. 5,420,482 and Yoksza et al. U.S. Pat. No. 5,410,328.
In both Phares U.S. Pat. No. 5,420,482 and Yoksza et al. U.S. Pat. No. 5,410,328, the LED modules are connected in series in a string or daisy chain configuration wherein a data stream is input to one LED module that extracts a subset of data for its module from the data stream and passes the remaining portion of the data stream or the entire data stream to the next LED module in the series. Lys et al. U.S. Pat. No. 7,253,566 and Mueller et al. U.S. Pat. No. 6,016,038 respectively disclose systems for lighting or illumination that include LED lighting units or nodes connected in a daisy chain configuration or a binary tree configuration with two nodes connected to the output of a single node. While Lys et al. U.S. Pat. No. 7,253,566 discloses a system in which addresses are assigned to each lighting unit by the system as opposed to being “manually pre-assigned,” the “self configuration” methods of Lys are not suitable for systems that do not employ a daisy chain configuration.
In accordance with the present invention, the disadvantages of prior systems and methods for assigning addresses to each of the pixel modules of the display have been overcome. The system and method of the present invention allows a pixel module to dynamically determine its location in a display, the location of the pixel module, forming an address for the display.
More particularly, a light module in accordance with one feature of the present invention is provided for use in a display having a two-dimensional array of light modules. The light module includes a module housing; a plurality of colored light elements mounted in the housing; at least three bi-directional data ports; and a controller within the module housing. The controller is coupled to each of the data ports and the controller identifies the location of the light module in the two-dimensional display in response to data received via a data port and the identity of the data port receiving the data.
In accordance with another feature of the present invention, a method of identifying the location of a light module in a two-dimensional array includes receiving data representing the identity of a segment or row number and a column number of a source light module that is the source of the received data and setting the column number of a light module to the column number of the source light module and the segment or row number of the light module to the segment or row number of the source light module incremented by a predetermined value if the data is received via a first data port of the light module.
In accordance with another feature, the method includes setting the segment or row number of the light module to the segment or row number of the source light module and column number of the light module to the column number of the source light module incremented by a predetermined value if the data stream is received via a second data port.
In accordance with a further feature, the method includes setting the segment or row number of a light module to the segment or row number of the source light module decremented by a predetermined value and the column number of the light module to the column number of the source light module if the data stream is received via a third data port.
In accordance with another feature, the method sets the column number of the light module to the column number of the source light module decremented by a predetermined value and the segment or row number of a light module to the segment or row number of the source light module if the data stream is received via a fourth data port.
These and other advantages and novel features of the present invention, as well as details of an illustrated embodiment thereof, will be more fully understood from the following description and drawings.
A large scale LED display 10 in accordance with the present invention, for indoor or outdoor use, has height by width dimensions on the order of 3 m×6 m to 24 m×32 m or approximately 10 ft.×20 ft. to 80 ft.×105 ft. Although, it should be appreciated, that the present invention can be used for displays that are larger or smaller as well. A display that is approximately 24 m×32 m has 480 pixels×640 pixels or a total of 307,200 pixels. Because such a display 10 is so large, only a portion of the display is depicted in
Each pixel of the display 10 is generated by a module 12, 14 having two red LEDs 16, two blue LEDs 18 and two green LEDs 20 mounted in a housing 22 as shown in
There are two types of pixel modules employed in the display 10, master LED modules 12 and slave LED modules 14. Each master module is associated with a group of slave modules in a segment 24 of the display. In accordance with a preferred embodiment of the present invention, each segment 24 has one master module and fifteen slave modules to generate 16 pixels of the display. It should be apparent, however, that the number of slave modules can vary from zero to any number depending upon which aspects of the invention are used. In a preferred embodiment, the segments 24 of the display 10 are linear, extending in a column of the display 10. However, the segments can alternatively extend in the rows of the display. Moreover, the segments need not be linear but can be formed of a block of modules that include at least one master LED module. For a 480×640 display having linear segments of sixteen pixels, there are thirty segments 24 in each column of the display. The segments 24 are preferably aligned so that each master module is in a row of master modules. As such, for a 480×640 display there are thirty rows of master modules with 640 master modules in each of those rows and fifteen rows of slave modules between each of the rows of master modules.
Each master LED module 12 is connected to the adjacent master LED modules in its row to allow direct communication therebetween. Each master module is also connected to the master modules of adjacent segments in its column to allow direct communication therebetween. As such, a master module is capable of communicating directly with up to four other master modules as well as each of the fifteen slave modules in the master module segment.
The display 10 is arranged in a number of panels 26, 27 for easier deployment. In accordance with a preferred embodiment of the present invention, each panel has sixteen columns of LED modules, wherein a full height panel has 480 rows of LED modules, although, each of the display panels can have any height and width desired. A 480×640 display having display panels with sixteen columns will employ forty display panels. Each display panel 26 can receive redundant data to control all of the pixels of the panel 26 from two data hubs, a primary data hub 28 and a redundant data hub 29. Each of the data hubs can provide the data for all of the pixels of two adjacent display panels 26 and 27 by providing two data streams, one data stream for the panel 26 and the other data stream for the panel 27. Moreover, each data hub is capable of providing redundant data to each display panel on two data cables. As such, the data hub 28 provides all of the data for the pixels of the display panel 26 on a data cable 30 and can provide redundant data for the panel 26 on a data cable 31. The display panel 26 can receive the same data for all of the pixels of the panel from the data hub 29 on data cable 32 or data cable 33. As such, the display panel 26 is capable of receiving data on any one of four data cables 30, 31, 32 and 33 from the two data hubs 28 and 29. The data hub 28 also provides all of the data for the pixels of the display panel 27 on a data cable 34 and can provide redundant data for the panel 27 on a data cable 35. The display panel 27 receives the same data from the data hub 29 on data cable 36 or data cable 37. As such, the display panel 27 is capable of receiving redundant data on any one of four data cables 34, 35, 36 and 37.
The redundant data streams received by a display panel 26 on the four data cables 30-33 are input to four respective master LED modules. However, in a preferred embodiment only one of the four redundant inputs is active to carry pixel data, at one time. A primary data hub only enables the redundant connection if the existing connection fails. Moreover, the redundant data hub only sends data to a panel if it detects that the primary data hub is no longer driving the panel. Each of the master modules receiving a data stream extracts the data intended for the master module and the associated slave modules in its segment. Each of the master modules receiving a data stream then outputs the data stream to the adjacent master modules in its row and to the master modules in adjacent segments as discussed in detail below. Each master module could strip off the data for its segment from a received data stream and send only the remaining portion of the data stream on to other master modules. However, in a preferred embodiment, each master module does not strip off its data from the data stream but acts as a repeater passing the entire received data stream directly to up to three other master modules after extracting a copy of the data for its segment from the data stream. The data stream for a display panel 26 is thus distributed throughout the panel 26 by each of the master modules 12. Because a master module 12 can receive a data stream from up to four other master modules 12, failure of one or two master modules will not render the display or even an entire column or row of the display inoperable as in prior art systems. Failure of one master module will affect only sixteen of the 307,200 pixels of a 480×640 pixel display 10. Failure of one slave 14 module will not affect any other modules of the display 10.
The system for controlling the display 10, as shown in
The communication hub 46 sends redundant data streams containing the data for the entire display 10 on a pair of GbE links 48 and 49 that are connected to respective data hubs 28 and 29. Each data hub is responsive to a received data stream to extract the columns of data for the two panels that the data hub controls, the data hub passing the remaining portion or the entire data stream as received on to another data hub. The data stream is thus distributed from data hub to data hub for all of the data hubs in the display system. Specifically, the data hub 28 receives a data stream containing the data for the entire display 10 on the GbE link 48. The data hub 28 extracts the data for columns 1-16 for the display panel 26 and the data for columns 17-32 for display panel 27 and then passes the entire data stream on a GbE link 50 to a data hub 51. The data hub 51 in turn extracts the data for the next pair of display panels in the sequence, display panels 52 and 53 and then passes the entire data stream to the data hub 56. Similarly, the data hub 29 receives the data stream containing the data for the entire display 10 on the GbE link 49. The data hub 29 extracts the data for columns 1-16 for the display panel 26 and the data for columns 17-32 for display panel 27 and then passes the entire data stream on the GbE link 54 to the data hub 55. The data hub 55 extracts the data for the display panels 52 and 53 and passes the entire data stream on to data hub 58. The distribution of the data stream continues to the pairs of data hubs until all of the data hubs controlling the display panel 10 have received their data for a frame of video. The data distribution then continues for all of the frames of a video presentation.
The structure of each data hub is depicted in
Each data hub, in addition to transferring video data to its associated pair of display panels, also performs diagnostics for its display panels. Power is supplied to the data hub from an associated power hub as depicted in
The structure of each of the master LED modules 12 is depicted in
Power for the master LED module 12 is received from power cables coupled to the module 12 from a power hub as shown in
The FPGA controller 90 as shown in
A master module enumeration state machine 112 performs an enumeration process to determine the location of the master LED module within a display panel 26 and thus, an address for the master LED module so that each pixel of the display can be individually addressed to deliver data thereto. The enumeration process performed by the state machine 112 is as follows. On power up of the display 10, the master LED module address registers that hold the segment number and column number of the master module in an enumeration state machine 112 are zero. The first master LED module enumeration message received is generated by the data hub and simply contains the segment number and column number of the hub. The enumeration message from the data hub is sent to only one master LED module. If that master module does not respond to the data hub, the enumeration message will be sent to another master LED module that is directly connected to a data hub. When a master LED module receives an enumeration message it determines its own location, i.e. address, in the display as follows. If the message is received on the master module's south port 93, the enumeration state machine 112 sets the master module's segment number equal to the segment number in the received message incremented by one and sets the master module's column number equal to the column number in the received message. If the enumeration message is received via the west port 94 of the module 12, the enumeration state machine 112 sets the module's segment number equal to the segment number in the received message and sets the master module's column number to the column number in the received message incremented by one. If the enumeration message is received via the north port 91 of the module, the enumeration state machine 112 sets the module's segment number equal to the segment number in the received message decremented by one and sets the column number to the column number in the received message. Finally, if the enumeration message is received via the east port 92, the enumeration state machine 112 sets the module's segment number equal to the segment number in the received message and sets the column number to the column number in the received message as decremented by one. The segment number and column number determined for the master module are stored in the module's address register. The enumeration state machine 112 overwrites the segment number and column number in the received enumeration message with the segment number and column number determined for its module. The enumeration state machine 112 then forwards this revised enumeration message out to three other master modules on three of the bidirectional ports 91-94, i.e. on all of the bidirectional ports 91-94 other than the one port 91-94 on which the enumeration message was first received.
As noted above, one input port 91-94 is selected at any time as the source of display data and messages from a data hub, this selected input port being designated as the upstream port. The downstream packet multiplexer 100 selects as the upstream port, the port whose associated input filter first declares or identifies a valid hub stream, i.e. a stream originating from a data hub. The three remaining ports 91-94 are designated as downstream ports. The upstream port is used in the downstream packet multiplexer 100 to determine which hub stream to forward and is used in an upstream packet multiplexer 109 to determine which ports to monitor for upstream packets. The upstream packet multiplexer 109 forwards MLM streams back towards the data hub. A hub stream that is received via the selected upstream port is forwarded and output from the master LED module via the three downstream ports to three other master LED modules if the upstream port selection is valid and the stream is a valid hub stream. In the reverse direction, MLM reply messages that are received on any of the three downstream ports are output from the module 12 on the selected upstream port if the upstream port selection is valid and the stream is a valid MLM stream.
Two conditions will trigger the downstream packet multiplexer 105 to select a different upstream port: the loss of synchronization from the data decoder associated with the initial upstream port or the stream type being received on the current upstream port changes to a valid MLM stream. When either of these conditions occurs, the downstream packet multiplexer 100 waits 1 msec and performs the upstream port selection process as described above.
A master packet processor 113 processes data hub packets that are addressed to the master module or that have segment and column header fields that are all zeros, i.e. a broadcast message such as used in the enumeration process. After the enumeration process for the display 10 has been completed such that each of the master LED modules has determined its location, i.e. segment number and column number in the display, and has selected an upstream port, a master packet processor 113 of the master LED modules can extract video data for its segment from a data stream. The master packet processor 113 of a master LED module extracts video data for its segment by detecting the master module's address in a received data packet and processes those data packets addressed to the master module. The extracted pixel data is written by the packet processor 113 to a message FIFO 108. At the end of the message a command byte is written to a command FIFO 115. The command FIFO 115 also holds information indicating whether a received message ended with a normal end of packet indication or not and a message byte count indicating the number of bytes in the message FIFO 114 for the received message. An I2C controller 116 reads and processes messages from the message FIFO 114 in response to commands in the command FIFO 115. The controller sends valid messages onto the I2C bus 92 so the message is broadcast to the master module micro-controller 80 and to each of the slave modules of the segment. In addition, the controller 116 sends slave LED module response data or status reply messages to the upstream processor 117.
The upstream processor 117 of the FPGA controller 90 maintains master LED module status information including the status of all four of the receivers 101-104. The upstream processor 117 caches slave module status information received on the I2C bus 92 in an internal RAM. The upstream processor 117 generates the master module and slave module status reply messages in response to strobes from the packet processor 113. The processor 117 also forwards status reply messages received from other master modules via the downstream ports and the upstream packet multiplexer 109 so that the status of each of the modules of a display panel are eventually transmitted back to the data hub for the display panel. Status messages are coupled to an upstream transmitter encoder 118 from the upstream processor 117 via an upstream FIFO 119 wherein the upstream transmitter encoder 118 is coupled to the transmitter 121-124 of the selected upstream port 91-94. Similarly, the state machine 112 couples a hub stream received via the master module's upstream port to the three designated downstream transmitters 121-124 associated with the three downstream ports 91-94 via a downstream FIFO 125 and a downstream transmitter encoder 126.
It should be appreciated that the master LED modules 12 are connected in a mesh configuration wherein each of the master modules 12, except those along an edge of a display panel 26, are connected to four other master LED modules 12. Each of the master modules 12 in this set is capable of receiving data from any of the four other master LED modules to which it is connected. However, each of the master modules 12 responds to a data stream from the one master module that is connected to its upstream port. As described above, a given master module will respond to the data stream from a master module connected to its upstream port to extract data therefrom and to send the received data stream out to the three other master LED modules that are connected to a respective one of its three downstream ports. If a first master module fails and that master module is connected to the upstream port of a given master module, the upstream port of the given master module is changed by its downstream packet multiplexer 100 to a different port so that the given master LED module can receive a data stream from one of the other three master LED modules to which it is connected. Because each master LED module can receive data from up to four other master modules, the data distribution scheme of the present invention is extremely robust.
The micro-controllers 80 and 130 of the master and slave modules have analog inputs to receive a red sense signal, a green sense signal and a blue sense signal. The micro-controllers monitor these sense signals to determine whether the respective LEDs are on or off. This information is included in the status information for each of slave and master LED modules 14 and 12. Each of the micro-controllers 80 and 130 also includes a built in temperature sensor that senses the temperature of the entire master module or slave module. A micro-controller may turn off the LEDs of a module if the temperature sensed for the module exceeds a predetermined limit.
The power hub 160 also includes an auxiliary transformer 180 that is coupled to one phase of the A.C. input via a one-phase breaker 182. A supervisory and control board 184 monitors all of the sensors of the power hub as well as the voltage from the auxiliary transformer 180. Initially, the main relay 166 and the soft start relay 169 are open. If the supervisory and control board 184 detects any incorrect signal via the auxiliary transformer voltage 180, start up is aborted. If the signals are correct, the control 184 initially closes the soft start relay 169, the relays for the fans 186 and the relays for a strip heaters 188. The controls 184 also allows 24V to be applied to external logic at this time. At this stage, the capacitors 174 can charge up slowly. If the voltage ramps up too fast or does not reach the correct output voltage, the control 184 opens the soft start relay 169 and the start up is aborted. If the correct voltage is reached, the main relay 166 is closed and the soft start relay 169 is opened. At this point, the display 10 can be powered up.
It is noted that the strip heaters 188 are employed to drive out humidity to prevent unwanted conductive paths leading to shorts or shock hazards. These heaters are controlled by the supervisory and control board 184 so that the heaters 188 are only on when needed. The fans 186 provide cooling for the power hub 160. In a preferred embodiment, the fans have speed sensors to which the supervisory and control board 184 is responsive to provide a warning of impending fan failure. Thermostats 190 are provided for the heat sinks and magnetics of the power hub 160. The supervisory and control board 184 includes a temperature sensor so as to provide an early indication of overheating. If the temperature of the power hub 160 exceeds a predetermined level, the supervisory and control board 184 will turn off the main relay 166 to stop overheating. The supervisory and control board 184 will also continuously monitor the D.C. output voltage of the power hub 160. If the control 184 detects output voltages that are too high, the control 184 will open the main relay 166.
Many modifications and variations of the present invention are possible in light of the above teachings. Thus, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as described hereinabove.
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