Patent Application
20140139115
The present invention relates to lighting devices and methods. In particular, the present invention relates to a method and system for the automatic color adjustment of a video display screen, panel, module or other display component comprising light emitting diodes.
Today, it is common for video displays to use light-emitting diodes (“LEDs”) because of the brightness and low power requirements of the LEDs. LED video screens are used as digital billboards to display e.g., advertisements, textual and/or graphical informational messages, and live or prerecorded videos throughout cities and towns and at sporting events, concerts, and other appropriate venues (e.g., inside or outside of buildings). LED video screens, also referred to as LED display walls, are made up of individual panels and/or intelligent modules (IM) having a predetermined number and arrangement of controllable LEDs. The panels and/or modules are mounted next to each other and their outputs are controlled such that they appear to be one large display screen.
Unfortunately, LEDs are known for decaying over time. This means that the LEDs will not be as bright and/or as colorful as they were prior to their first use. Thus, after monthly and yearly operation of an LED video screen, the LEDs on the panels, modules, etc. that make-up the screen will eventually decay, affecting the brightness and/or color of the screen. Depending upon how the LED video screen was being used and what it had been displaying, the decay level of the LEDs on the individual panels and modules may be different from panel to panel and module to module. That is, because some LEDs will be used more frequently than others depending upon e.g., their location and what the screen was being used to display, uniformity of the screen (particularly with respect to it brightness and color output) will get worse over time.
Currently, there are techniques for adjusting the LED screen's color and brightness, but they are manually intensive. As used herein, the term “color adjustment” will refer to color and or brightness adjustment. Oftentimes a web camera, or other digital camera, is used with other equipment external to the LED screen to capture the screen's output. The external equipment includes, but is not limited to, light sensors and a computer that are separate from the screen's control panel. Moreover, a human operator is required to set up and control the equipment, determine test results, and execute the adjustment process. The external equipment and need for a human operator renders the typical automatic color adjustment technique costly, time consuming and inefficient.
Accordingly, there exists a need to provide an automatic color adjustment scheme for a video screen, display panel, module or other component comprising light emitting diodes.
In consideration of the above problems, in accordance with one aspect disclosed herein, a light emitting module is provided. The module comprises a plurality of display light emitters connected to a first side of a circuit board; a reference light emitter connected to a second side of the circuit board; and a first circuit for determining an amount of decay experienced by the plurality of display light emitters based on light emitted from the reference light emitter.
In another embodiment, a light emitting video screen is provided. The screen comprises a plurality of light emitting modules. Each light emitting module comprises a plurality of display light emitters connected to a first side of a circuit board; a reference light emitter connected to a second side of the circuit board; and a first circuit for determining an amount of decay experienced by the plurality of display light emitters based on light emitted from the reference light emitter.
In yet another embodiment a light emitting video system is provided. The video screen comprises a plurality of display light emitters and a plurality of reference light emitters; and a controller coupled to control the video screen and perform automatic adjustment of the plurality of display light emitters based on light output from the reference light emitters.
In a further embodiment, a method of performing automatic color correction of a light emitting video screen comprising a plurality of light emitting modules is provided. The method comprises for each module, inputting a current light level from a reference light emitter on the module; for each module, comparing the current light level to a reference level of the reference light emitter to an output level of the module; comparing the output levels of all of the light emitting modules to determine the lowest light level; and adjusting the light level of all of the modules such that all of the display light emitters have the determined smallest light level.
The figures are for illustration purposes only and are not necessarily drawn to scale. The invention itself, however, may best be understood by reference to the detailed description which follows when taken in conjunction with the accompanying drawings in which:
In accordance with preferred embodiments disclosed herein, a system and method for performing automatic color adjustment on an LED video screen, display panel, module or other component is provided. The disclosed system and method periodically or constantly ensures the uniformity of the LED video screen, etc. automatically and without the need for human intervention.
As such, the disclosed system and method is more efficient and less costly than today's manual color adjustment schemes.
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Spaced apart from the reference LED 26 is a light sensor 28 that is also secured to the circuit board 24 (not shown) or other portion of the module 20. During the initial use of the module 20 (i.e., at the factory) and during the automatic adjustment process, the light sensor 28 will sense the output from the reference LED 26 and output a corresponding signal to the same processor or control panel that is used to drive the reference LEDs 22. It should be appreciated that there is no need for the light sensor 28 to sense the output of the reference LED 26 unless the output is needed for the automatic color adjustment process (described below).
The system 10 includes a first memory device 30 that stores the color/brightness information from the reference LED 26 (via the light sensor 28) upon the initial use of the module 20. This may occur at the factory where the module 20 was manufactured and initially set-up and tested. In a desired embodiment, the first memory device 30 will store the color/brightness information from the reference LED 26 (via the light sensor 28) upon the initial use of the module 20 in the LED video screen with its control panel. As will become apparent, the information stored in the first memory device 30 will be used as a reference level (i.e., 100% fully functional LED 26 without decay) throughout the automatic color adjustment process. The system 10 includes a second memory device 32 that stores the current color/brightness information from the reference LED 26 (via the light sensor 28) after the initial use of the module 20. The information in the second memory device 32 will be updated every time the automatic color adjustment process is executed to ensure that the current state of the reference LED 26 is captured.
The first memory device 30 is preferably a non-volatile memory device (e.g., a programmable ROM such as a serial programmable read only memory (“SPROM”), electrically erasable programmable read only memory (“EEPROM”), battery backed random access memory (“BRAM”), etc.) and preferably resides in the module 20. The second memory device 32 can be part of the first memory device 30 if the first memory device 30 is a programmable non-volatile memory (e.g., an EEPROM or BRAM). The second memory device 32 could be a separate memory device or hardware register, if desired. It should be appreciated that the second memory device 32 does not need to be a non-volatile memory device as its contents will be periodically changing. Moreover, the second memory device 32 is preferably contained within the module 20, but it should be appreciated that the second memory device 32 could reside within the screen's control panel as a separate memory or as part of a larger memory and can even be represented by a software table.
The information in the two memory devices 30, 32 will be compared (shown as a separate “comparing” component 38) and analyzed by the processor or control panel to determine any decay that the reference LED 26 is experiencing. Hereinafter, the term “control panel” will be used to refer to a processor, controller or control panel used to control the LED video screen and its individual modules 20. The comparing component 38 can be implemented in hardware or software and preferably resides on the module 20. It should be appreciated, however, that the comparing component 38 does not need to be a separate component from the control panel and that the present embodiment should not be limited as such. That is the function performed by the comparing component 38 can be implemented by the control panel, if desired.
The switch 36 is controlled by the control panel when it is time to perform the automatic adjustment process. Thus, all of the components of the system 10 that are necessary to perform the automation color adjustment are part of or reside within the module 20 such that they can be driven by the control panel, output results of the comparison, and implement the needed dot correction as directed by the control panel. It should be appreciated that the illustrated embodiment is not limited to this switching arrangement and that all of the comparing functions, analyzing of the compared signals and the implementation of the dot correction can be performed by the control panel, if desired.
During normal operation of the video screen 100, each reference LED 26 is driven in the same manner as the display LEDs 22, this way the reference LEDs 26 experience the same decay as the display LEDs 22. When it is time to run the automatic adjustment process, the control panel drives the reference LEDs 26 with the 100% white color and switches the switches 36 such that the sensed outputs of the reference LEDs 26 (via the sensors 28) are sent to the associated comparing components 38. The outputs from the comparing components 38 are processed by the lone control panel used to control the screen 100, which determines the percentage each module 20 has decayed. The control panel subtracts the percentage of decay from 100% to determine each module's 20 current color/brightness percentage. The control panel then assigns the new color/brightness percentage to each module 20 in the screen 100.
The processor switches the switch 36 to the second position and outputs the uniform color/brightness level to the dot correction component 40 on each module 20 (via the comparing component 38). Each module 20 is then corrected by the dot correction component 40 such that all display LEDs 22 of each module 20 operate at the uniform color/brightness percentage.
It should be appreciated that the control panel could perform the automatic color adjustment process periodically at any desired rate. A timer or other mechanism on the control panel could be used so that uniformity can be kept automatically. By having all of the system 10 within the individual modules 20, no human intervention or external equipment is required to implement the disclosed automatic color adjustment scheme except for the same control panel that id used to operate the screen 100. As such, the system and method disclosed herein is more efficient and cost effective than traditional adjustment processes.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.
