Abstract:
A system and method for color changing lighting comprising a pre-programmed controller along with driver circuit, a single or combination of LEDs and an OFF/ON switch which is used for making selection of mode of operation as well as switching the system ON/OFF. Brightness is changed using pulse width modulation. The LED&#39;s are selectively activated by programmed variable pulse to generate desired color mixing effect. The resulting illumination may be controlled by a computer/micro-controller program to provide pre-designed complex patterns of light in virtually any environment.

Description:
STATEMENT REGARDING COPYRIGHTED MATERIAL  
       [0001]     Portions of the disclosure of this patent document contain material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office file or records, but otherwise reserves all copyright rights whatsoever.  
       FIELD OF INVENTION  
       [0002]     This invention generally relates to Light Emitting Diodes (LED) lighting systems, and more specifically to a method and apparatus of controlling one or more LED lights in order to provide different colors, and still more precisely to provide different colors, achievable by the system, to the individual LED or combination thereof by digital programming and a time sensitive on-off switching method.  
       BACKGROUND OF THE INVENTION  
       [0003]     LEDs are commonly used in lighting applications, and have in many areas superseded conventional lighting, including decorative elements, indicators etc. LEDs have various advantages: they are cost effective, easy to implement and typically consume very little power. Furthermore, LEDs may be employed to produce a lighting system with a varying color scheme, which is often desired for applications such as lamps, back light sources, traffic signals, display boards, illuminating switches and commercial lighting. LEDs provide the best option for these applications as they are easily available in basic colors Red, Green and Blue (RGB) and any other colors can be produced by manipulating the intensity of these basic colors RGB.  
         [0004]     U.S. Patent publication number US 2004/0207334 discusses a system for a color changing bulb for the instrument panel of a vehicle, which is made as a bulb and directly installable in a bulb seat of the instrument panel. The color changing bulb includes a bulb housing defining a receiving space for receiving a light emitting diode and a circuit board. The LED includes three LED chips for generating red, blue and green light components. A controlling circuit is disposed on the circuit board and connected with the LED for driving the three-color LED chips to emit light. By use of a brightness adjustment switch on the instrument panel or a headlight switch, at least seven combinations of colors of light can variably emitted. This patent provides a memory unit to store or count the number of times the headlight switch is switched to create additional signal indicating which color the LED system should produce. This system is further using stabilizing unit and a digital cycle outputting unit, which makes it limited to only cyclic color changes and does not provide with an option for selecting a single color and the system can not be programmed for selecting flashing or steady state color mode.  
         [0005]     In another US Patent publication, number US 2002/0047628, a system is discussed which is more complicated and requires a more complex infrastructure to control and use the system, making it both bulky and costly. This art is used in larger applications such as in decorating retail, commercial and residential places; thus limiting this system to outdoor environments. It is not cost-effective in smaller applications.  
         [0006]     In another U.S. Pat. No. 5,420,482, a color display apparatus is disclosed in which each of the three color LED in the circuit are driven by transistor biasing. In this system, each transistor base is coupled to a respective latch resistor. As the three latches are connected to a single data bus, it becomes impossible to change the color of all the three LED&#39;s at a very high speed. Also, the biasing of the transistor was changed by simply changing the grounding resistor of the potential divider which may vary from piece to piece due to component tolerance.  
         [0007]     U.S. Pat. No. 6,016,038 to Mueller, et al. discloses a pulse width modulated current control for an LED lighting assembly, where each current-controlled unit is uniquely addressable and capable of receiving illumination color information on a computer lighting network. The light module is adapted to be conveniently interchanged with other light modules having programmable current and hence maximum light intensity, ratings. The pulse width modulated LED lighting assembly of this invention however necessitates the use of a computer controller to operate the system.  
         [0008]     U.S. Pat. No. 6,150,774, also to Mueller, et al. discloses a similar pulse width modulated current control for an LED lighting assembly wherein each current-controlled unit is uniquely addressable and capable of receiving illumination color information on a computer lighting network. This patent anticipates the use of a manual control for an LED lighting assembly, however there is no method for manually programming an LED light source with such a method.  
         [0009]     U.S. Pat. No. 6,211,626 to Lys, et al. discloses a light module, comprising an LED system for generating a range of colors within a color spectrum, a processor for controlling the amount of electrical current supplied to the plurality of light emitting diodes, so that a particular amount of current supplied thereto generates a corresponding color within the color spectrum, a housing within which the LED system is positioned, and a heat spreader plate in contact with the housing for dissipating heat from the housing; wherein the LED system includes a thermal connection to the heat spreader plate. This invention fails to provide for a manual, switched color or color array setting mode.  
         [0010]     U.S. Pat. No. 6,340,868 to Lys, et al. discloses a light module having a plurality of light emitting diodes for generating light of a range of colors within a color spectrum, a processor for controlling the amount of electrical current supplied to each light emitting diode such that a particular amount of current supplied to the light module generates a corresponding color within the color spectrum, and a power module for providing electrical current from a power source to the light module, the power module including a connector for removably and replacably connecting the power module to the light module. However, this invention contemplates a computer controlled multicolored lighting network, rather than individual lighting units which may be programmed to multiple modes in a series by a manual switch.  
         [0011]     U.S. Pat. No. 6,528,954 to Lys, et al. also relates to LED lighting assemblies, however this patent claims the use of a processor to control current through the LEDs, rather than a technique to control pre-programmed modes through a manual switch.  
         [0012]     U.S. Pat. No. 6,806,659 to Mueller, et al. discloses a pulse width modulated current control for an LED lighting assembly, wherein each current-controlled unit is uniquely addressable and capable of receiving illumination color information on a computer lighting network. In a further embodiment, the invention includes a binary tree network configuration of lighting units (nodes). In another embodiment, the present invention comprises a heat dissipating housing, made out of a heat-conductive material, for housing the lighting assembly. The heat dissipating housing contains two stacked circuit boards holding respectively the power module and the light module. The light module is adapted to be conveniently interchanged with other light modules having programmable current, and hence maximum light intensity, ratings. Like the other background references, this invention doesn&#39;t contemplate an LED lighting assembly, wherein the ON/OFF switch is also the color control.  
         [0013]     The above mentioned prior art does not provide choice of selection of cyclic or steady state color modes. Although several instances of the prior art have the capability of generating a variety of combinations, they lack the ability to make color changes without large, costly, complex controllers, and are not suitable for use in small applications. Furthermore, these arts do not provide any memory means to store a mode of operation and color or color combination when they are switched off, to restore a variety of predetermined settings at the time of the next restart.  
       OBJECT OF THE INVENTION  
       [0014]     Therefore it is one object of the invention is to provide a light emitting diode system.  
         [0015]     It is a further object of the present invention to provide choices of flashing or steady state color selection of lighting of LEDs.  
         [0016]     A further object of the present invention is to reduce the complexity of the system, and to make the system comparatively cost effective, small, intelligent and efficient.  
         [0017]     Yet another object of this invention is to simplify the selection process of flashing or steady state light operation, within a stipulated time limit, so that anyone, irrespective of age or knowledge, can use the system effectively.  
         [0018]     Still another object of the present invention is to provide with a memory means to store the system&#39;s mode of operation and display color, and to restore a variety of predetermined settings at the time of a subsequent system restart.  
       SUMMARY OF THE INVENTION  
       [0019]     The present invention comprises a system and method for color changing lighting, having a pre-programmed controller with driver circuit, single or combination of LEDs and an OFF/ON switch which is used for making a mode of operation selection as well as switching the system on and off. The brightness of the LED or combination of LEDs is changed using pulse width modulation.  
         [0020]     This system is capable of working on a regulated or unregulated power supply and the drive circuit of the system is provided with an external resistor to set the drive current for different LED arrays and it keeps equal current in each leg of LEDs in varying forward voltage with the help of transistors. The LED&#39;s are selectively activated by programmed variable pulses to generate the desired color mixing effect. The controller controls the lighting mode and color of said LEDs, it uses 8 bits of data in the presented embodiment, to provide maximum of 256 intensity levels per LED, thereby giving a smooth transition from one color to other.  
         [0021]     The controller uses an external crystal which allows all light modules in the system to be synchronized, and is capable of storing the mode and color (or combination of colors) at the time it is switched off. In an alternate embodiment, an internal oscillator may be used for synchronization; however the preferred mode uses an external crystal for accuracy. The system provides options for selecting one mode of two different modes of operation; namely rotating color mode and fixed color mode.  
         [0022]     When the system is initially powered on, a user may select from a variety of color modes. A user can switch from mode to mode by turning the power off and on within a first predetermined time, called the “switching time.” In the present embodiment, for purposes of illustration, a period of 5 or less is proposed. All mode switching operations must be completed within a second predetermined time, called the “synchronize time.” For purposes of illustration, a period of 10 seconds is proposed. Each time the power is turned off and on in under five seconds, from the first time the power is turned on until the end of the synchronize time at ten seconds, it starts in a new mode. To select a mode, a user simply leaves the system on until the end of the synchronize time.  
         [0023]     Each mode is characterized by either a changing, selectable or static light pattern of one or a variety of colors, and each mode has a corresponding indicator pattern that is displayed by the LEDs of the system during the synchronize time. When the synchronize time ends, the LEDs go from displaying the indicator pattern to either a color changing cycle or static color of the mode selected.  
         [0024]     For instance, in a system with standard red green and blue LEDs, when the power is initially switched on, a green LED may blink to indicate a first (default) mode. If the power is turned off for less than five seconds and back on again, a red blinking LED may be used to indicate that the system has switched to a second mode. If the power is then turned off a third time and back on within five seconds, the system goes into a third mode, reflected perhaps by a blue LED indicator.  
         [0025]     If the mode is switched again after the last selectable mode, it cycles back to the first (default) mode. At the end of the synchronize time, the system goes into the mode selected. If the power is switched off and on in under five seconds once the synchronize time is over and the system has switched into a particular mode, the system restarts at the beginning of a new synchronize time in the first (default) mode.  
         [0026]     The number of modes is only limited by the possible combinations of static or blinking colors or combinations of colors of LEDs, and each mode may be characterized by different characteristics, such as a constantly changing color pallet, a changing color pallet that remembers the final color selected and stays there, or a pallet that moves between two selected colors, etc.  
         [0027]     If a mode is selected that is characterized by a static color, That color will be displayed each time the system is turned on, as long as the interval between powering off and back on is more than the switching time (in the present embodiment, 5 seconds). If the system is turned off and on in less than the switching time, it reverts to the first default mode and a new synchronize time starts. If a color changing mode is selected, once the synchronize time ends, the system goes into that mode&#39;s color changing cycle.  
         [0028]     A color changing cycle cycles through all or a range of the system&#39;s possible colors in a predetermined time. In one embodiment, it may take 60 seconds to cycle through all of the colors of a system. The range of possible colors in a particular cycle depends on the characteristics of the mode. For instance, one color changing mode may cycle through all possible colors. A second color changing mode may be limited to colors between orange and purple, etc. The number of modes is limited only by the number of combinations of colors, and blinking rates possible in the LED array. While not infinite, a very large number of modes are possible in any given system.  
         [0029]     Color changing modes may be either continuous, or selectable. A continuous color changing mode constantly cycles through its range of colors. When the system is powered off for a period greater than the switching time (5 seconds in the present embodiment), once it is powered on again, the color continues to cycle starting from any predetermined position, including the last color displayed before the power was turned off.  
         [0030]     By contrast, a selectable color cycle cycles through a range of colors just like a continuous cycle. However, when a selectable cycle is powered off for a period greater than the switching time, it retains the last displayed color as a static color once it is powered on again, and retains that color until the system is reset by powering off and on in a period less than the switching time. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0031]      FIG. 1  shows a basic block diagram of the presented work.  
         [0032]      FIG. 2  shows a simple block diagram of the circuit.  
         [0033]      FIG. 3  shows circuit diagram of color changing system.  
         [0034]      FIG. 4  shows the electrical circuit for LED board.  
         [0035]      FIG. 5  shows a simple block diagram of the flow of the program in the presented system.  
         [0036]      FIG. 6  shows the flow chart of the program work. 
     
    
     REFERENCE NUMERALS  
       [0000]    
       
           1  . . . User interface  
           3  . . . Micro controller  
           5  . . . LED Drivers green, red and blue  
           7  . . . Single or combination of green, red, blue LEDs  
           9  . . . Ground  
           11  . . . Power supply block  
           13  . . . User interface block  
           15  . . . Power regulator block  
           17  . . . Controller block  
           19  . . . LED board  
           21  . . . Power ON test block  
           23  . . . Selection (synchronize time or switching option mode) block  
           25  . . . Cyclic/rotating colour mode block  
           27  . . . Fixed colour mode block  
       
     
       REFERENCE NUMERALS FOR FLOW CHART  
       [0000]    
       
           0  . . . No  
           10  . . . Yes  
           41  . . . Start  
           43  . . . Power on test  
           45  . . . Selection block  
           47  . . . Check for switching  
           49  . . . Change mode  
           51  . . . Time check  
           53  . . . Mode check  
           61  . . . Start rotating mode  
           63  . . . Check switching  
           65  . . . Save mode and color  
           67  . . . Check time  
           68  . . . Start rotating mode  
           69  . . . Save option  
           71  . . . Start fixed mode  
           73  . . . Check switching  
           75  . . . Save color  
           77  . . . Check time  
           78  . . . Restart last color  
           79  . . . Save mode and color  
           100  . . . Selection of fixed color mode  
           200  . . . Selection of rotating color mode  
       
     
       DETAILED DESCRIPTION  
       [0074]     A further understanding of the present invention may be obtained with reference to the following description taken in conjunction with the accompanying drawings. However, the embodiments used for describing the invention are illustrative only and no way limiting scope of the invention. A person skilled in the art will appreciate that many more embodiments of the invention are possible without deviating from the basic concept of the invention any such embodiment will fall under the scope of the invention and is a subject matter of protection.  
         [0075]      FIG. 1  shows a basic block diagram of the presented work, the user interface  1  gets the ON/OFF input and sends it to the micro controller  3  which drives the LED Drivers  5 . the driver circuit drives single or combination of red, blue and green lighting devices or LED&#39;s  7 , which are used as the light source, and according to the inputs and micro controllers signals, the LED&#39;s emit light.  
         [0076]      FIG. 2  shows a simple block diagram of the circuit of presented which consists of power supply  11 , user interface  13 , power regulator block  15 , controller  17  and LED board  19 . When the power supply  11  is on and there is an input at user interface, the controller block  17  sends control signals to the LED board  19  according to the function selected. The LED board  17  receives the regulated power from the power regulator block  15  for the proper LED output.  
         [0077]      FIG. 3  shows a circuit diagram of the present invention which is designed to operate on low voltage. It contains a power supply unit with a 2 point connector that receives the 12 V AC input from the step down transformer (not shown in the figure). The bridge assembly consisting of rectifier diodes D 8 , D 9 , D 10 , D 11  which convert the AC into a pulsating DC signal. This signal is then fed to the power regulator section which regulates the voltage to 5 V LED drive circuit. Although a 5 LED drive circuit is contemplated in this example, the present invention also contemplates a range of line voltages from any regulated or unregulated power supply.  
         [0078]     Filter capacitors C 1 , C 2 , C 3 , C 4  and linear 5 V regulators (LM7805 and LM 2576 in the present example) are used for high current application. The pulsating DC signal is applied to the user interface which senses the switch ON/OFF time period and changes the state of the light accordingly. The Zenner diode D 7  keeps the input signal to the MCP100 at fixed level when power is on at 5.1 V. The output of the MCP100 changes to low as soon as the power is off, and provides active low switch input for the micro-controller. The user interface provides input to the micro-controller PIC12F629. The controller communicates with the user using pin number 4 to detect a power fail. The microcontroller runs at 8 bits so that 256 possible voltage levels for can be achieved. Thus  256  current values and equivalent levels of intensity per LED are achieved. An external crystal Y 1  provided with the microcontroller synchronizes all light modules.  
         [0079]     The digital signal from pins  5 ,  6 ,  7  control the intensity of R,G,B LEDs respectively by turning on and off LED driver chips, using Q 1 , Q 2  and Q 3 . An external resistor allows the circuit designer to set the drive current for different LED arrays. It also supplies constant current for varying input voltage. External resistors R 4 , R 5 , R 6  allow current to be set, upto 350 mA of each leg of distinct color LEDs. The control card which uses IC&#39;s numbered NUD 4001 connects with the LED board where the color changing LED or combination of LEDs are connected.  
         [0080]      FIG. 4  shows the electrical circuit of the LED boards used in the present embodiment. In the circuit diagram, one LED each of red, blue and green or an array of green, blue and red LED&#39;s are used as the light source. This LED board design is such that despite variations in forward voltage from different LEDs, the current remains equal in each LED or LED array with the help of the transistors in the LED board.  
         [0081]      FIG. 5  shows a simple block diagram of the flow of the program in the presented system. Power on test Block  21 : when the power is on for the first time, the first (default) mode LED will blink or flash, and the system goes into synchronize time. Block  23 : during synchronize time a user has the option of switching modes. The selection block checks for the user&#39;s selection of the mode for running on the system for a fixed time and accordingly switches to the respective block rotating color mode  25  or fixed color mode  27 . These respective blocks run the mode until the user interface supplies some other input to return to a subsequent instance of synchronize time. When system is switched off after use, the mode of operation and color or color combinations are stored and the settings are restored until the next restart.  
         [0082]      FIG. 6  shows a flow chart of the program of the system, where  0  presents a flow of a logic NO and  10  represents flow of a logic YES in selection blocks of the flow chart. The system starts at  41 , followed by power on test  43  and a selection block  45  if system is powered on, these steps of operation are named as “synchronize time” or “switching option mode” with a predetermined cycle time. Here, block  47  checks for switching operation by the user. If switching is done, the mode is changed depicted by the block  49 , and a time check is performed in block  51 , if the predetermined synchronize time limit is not over, the control goes to the block  47  again otherwise a check is performed for mode of operation selection in block  53 .  
         [0083]     If the mode is set to rotating color, the operation starts with the block  61  and the indicator LED for the mode starts blinking, depicting the rotating color mode of operation. Block  63  checks for the switching operation if switch is pressed control goes to block  65  where the program stores the last color and mode of operation of the system, and in the next control block  67 , checks for the time lag of the switching. In the present example, if switching is more than 5 seconds, the system starts with the last mode selected and starts at a predetermined position from block  61 , otherwise the control goes back to block  45 .  
         [0084]     If the mode of operation selected is fixed color mode, the indicator LED for that mode starts indicating the fixed color mode of operation. In this mode, the system starts with a rotating color mode block  71 , which allows the user to select from the available choices. Block  73  checks for the switching operation. If the switch is pressed, control goes to the next block  75  where the system saves the last color and mode of operation. A check is performed in block  77  to determine if the time between pressing the switch is more than 5 seconds, if it is, the system reinstates the last color position and control goes back to step  73 . If it is not, control goes to block  79  where the system saves the color and mode of operation and control goes to block  45 .  
         [0085]     Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. For example, the present invention can be utilized in other contexts such as military installations or in-house corporate departments without departing from the spirit or intent of the invention. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.  
         [0086]     Any element in a claim that does not explicitly state “means for” performing a specific function, or “step for” performing a specific function, is not to be interpreted as a “means” or “step” clause as specified in 35 U.S.C. § 112, paragraph 6. In particular, the use of “step of” in the claims herein is not intended to invoke the provisions of 35 U.S.C. § 112, paragraph 6.