Patent Publication Number: US-11026306-B2

Title: Variable-intensity LED module, system and light fixture

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage Application under 35 U.S.C. § 371 of PCT International Application No. PCT/US2019/012082, filed Jan. 2, 2019, which claims priority to U.S. Provisional Patent Application No. 62/612,871, filed Jan. 2, 2018, the entire contents of which are incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Solid state lighting has become increasingly used in lighting applications. Light emitting diodes (LEDs) are commonly used in such applications. The size of LEDs and control over the intensity of generated light provides versatility. Standard LED circuits, however, are typically fixed with a target intensity, such intensity possibly being varied by a dimmer circuit. 
     SUMMARY OF THE INVENTION 
     In a first aspect, the subject invention provides a variable-intensity light emitting diode (LED) module which includes: a board; a first LED string, mounted to the board, having first and second ends, the first end being connected to a positive voltage terminal which is connectable to a positive voltage input of a direct current voltage source; a first terminal, mounted to the board, connected to a first resistor which is connected to the second end of the first LED string; and, a second terminal, mounted to the board, connected to a second resistor which is connected to the second end of the first LED string. The first and second resistors have different resistances. A negative voltage input of the direct current voltage source is selectively connectable to one of the first and second terminals, whereby, the intensity of light generated by the first LED string is determined by which of the first and second terminals is connected to the negative voltage input. Advantageously, the subject invention provides a variable-intensity light module which may be used in a larger system and in a light fixture. 
     These and other features of the subject invention will be better understood through a study of the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a LED module formed in accordance with the subject invention. 
         FIG. 2  is an enlarged view of a section of the module of  FIG. 1 . 
         FIGS. 3-4  are schematics of circuitry allowing for varying intensity of light generated by a LED module in accordance with the subject invention. 
         FIGS. 5-6  are schematics of a current regulator and switch which may be optionally utilized with the subject invention. 
         FIGS. 7-10  show different connectors useable with the subject invention. 
         FIG. 11  is a perspective view of a system formed in accordance with the subject invention. 
         FIG. 12  shows jumper cables useable with a system in accordance with the subject invention. 
         FIG. 13  is an exploded view of a light fixture formed in accordance with the subject invention. 
         FIGS. 14A-14F  show installation and preparation of a light fixture in accordance with the subject invention. 
         FIG. 15  shows variations of a light fixture in accordance with the subject invention. 
         FIG. 16  shows schematically a driver and dimmer configuration useable with the subject invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the Figures, a variable-intensity light emitting diode (LED) module is shown and generally designated with the reference number  10 . The module  10  generally includes a printed circuit board (PCB)  12 , a plurality of LED strings  14  mounted to the board  12 , and circuitry mounted to the board  12  to allow for varying the intensity of light generated by the LED strings  14 . The board  12  may be of any known type with all connections being formed on the board  12  using known techniques, including using known trace techniques. The LEDs  16  of the light strings  14  may be of any type include standard LEDs, organic LEDs (OLEDs), and polymeric LEDs (PLEDs). The LEDs  16  may be white LEDs, but other colors may be utilized as well. 
     The board  12  may be of any dimension, including being elongated, as shown in  FIG. 1 . This allows for the module  10  to form a strip of light. The LED strings  14 , although wired in parallel, may be physically arranged in an end-to-end fashion. This allows for a continuous strip to be formed. It is preferred that the LEDs  16  be evenly spaced along the length of the board  12 , including within the LED strings  14  and between the LED strings  14 . Thus, as shown in  FIG. 2 , intra-string spacing S 1  represents on-center spacing between two of the LEDs  16  on the same LED string  14 , while inter-string spacing S 2  represents on-center spacing between two LEDs  16  of different LED strings  14  (i.e., spacing between the terminal LEDs of two adjacent LED strings  14 ). To maintain even spacing along the full length of the board, the spacing S 1  is preferably equal to the spacing S 2 . Both S 1  and S 2  may be equal to 0.25 inches. Even spacing allows for a generally continuous presentment of generated light, thus, minimizing dark spots along the module  10 . In addition, even spacing allows for the module  10  to be provided with a rating based on length, such as, light production per increment of length (e.g., lumens/foot), an amount of current consumed per increment of length (e.g., milliamperes/foot), and/or, amount of power consumed per increment of length (e.g., watts/foot). 
     The module  10  is provided with variable intensity allowing for users to select different levels of light intensity for the same module  10 . As shown in  FIG. 3 , in one embodiment, the LED strings  14  are wired in parallel, with any quantity of the LED strings  14  being utilized, the quantity being generally a function of the length of the board  12 . The LED strings  14  each have a first end  18  and a second end  20 , with the first ends  18  of all the LED strings  14  being connected to a positive voltage terminal  22  which is connectable to a positive voltage input of a direct current voltage source, such as a driver, battery, solar panel, and so forth. The direct voltage source may be provided separate from the module  10 , such as being included in a light fixture along with the module  10 . The direct current voltage source may be set to provide 24 VDC to the module  10 , both other levels of direct current voltage may be utilized. 
     The module  10  further includes a first terminal  24  and a second terminal  26 . The first and second terminals  24 ,  26  are connected in parallel to each of the second ends  20  of the LED strings  14 . A first resistor  28  is provided between the first terminal  24  and each of the second ends  20  of the LED strings  14 . In addition, a second resistor  30  is provided between the second terminal  26  and each of the second ends  20  of the LED strings  14 . It is preferred that all of the first resistors  28  be provided with the same resistance and that all of the second resistors  30  be provided with the same resistance. The first resistors  28  are set to a different resistance from the second resistors  30 . With this arrangement, a negative voltage input of the direct current voltage source may be selectively connected to one of the first and second terminals  24 ,  26 , with the intensity of the light generated by the LED strings  14  being determined by which of the first and second terminals  24 ,  26  is connected to the negative voltage input. The difference in intensity is defined by the resistances of the first and second resistors  28 ,  30 . A higher resistance causes less current flow to the LED strings  14  and, thus, less light intensity. Thus, for example, setting each of the first resistors  28  to a resistance of 150 ohms and setting each of the second resistors  30  to a resistance of 75 ohms will result in the second terminal  26 , with negative voltage applied thereto, allowing for generally twice the intensity of light being generated by the LED strings  14  as compared to light generated by the LED strings  14  with negative voltage applied to the first terminal  24 . 
     The intensity of light generated by LEDs may be characterized in terms of color temperature with higher temperature correlating to more intense (brighter) light. The intensity of light of the module  10  may be controlled by varying the colors of the LEDs  16 , including using red, blue, green, warm white, and cool white LEDs in various combinations. As appreciated by those skilled in the art, the colors of the LEDs  16  cannot be varied during use, with intensities being varied by the amount of current delivered to the LEDs  16 , as described above, and through the optional use of a dimmer, as described below. 
     As will be appreciated by those skilled in the art, the number of terminals  24 ,  26  may be varied with the subject invention to allow for various intensities of light to be generated by the module  10 . For example, as shown in  FIG. 4 , a third terminal  32  may be provided connected to each of the first ends  18  of the LED strings  14 , in parallel to the first and second terminals  24 ,  26 . A third resistor  34  may be provided between the third terminal  32  and each of the second ends  20  of the LED strings  14 . It is preferred that all of the third resistors  34  be provided with the same resistance. The third resistors  34  are set to a resistance different from the resistances of the first and second resistors  28 ,  30 . This allows for a third level of intensity to be achieved with the module. For example, each of the third resistors  34  may be set to a resistance of 35 ohms. This allows for more intense light to be generated by the LED strings  14  with negative voltage applied to the third terminal  32  as compared to the light generated through use of either the first terminal  24  or the second terminal  26 . 
     With reference to  FIGS. 5 and 6 , a second embodiment is provided where constant current is provided to the LED strings  14 . In particular, for each of the LED strings  14 , a current regulator  36  is provided in parallel to the respective first, second, third resistor  28 ,  30 ,  34 . For example, for each of the LED strings  14 , a first current regulator  36 A is provided in parallel to the first resistor  28 , a second current regulator  36 B is provided in parallel to the second resistor  30 , and a third current regulator  36 C is provided in parallel to the third resistor  34 . Any configuration of current regulator may be utilized which provides constant voltage across the respective first, second, third resistor  28 ,  30 ,  34 . By way of non-limiting example, each of the current regulators  36  may include a Zener diode  38 . Bias lines  40  are provided, as shown in  FIG. 5 , to carry positive voltage from the positive voltage terminal  22  to each of the Zener diodes  38 . The Zener diodes  38  provide a constant voltage, e.g., a voltage of 1.24 VDC, across the respective first, second, and third resistors  28 ,  30 ,  34 , e.g., between lines  39   a  and  39   b . With constant voltage across the respective first, second, third resistors  28 ,  30 ,  34 , constant current may be delivered therefrom. 
     Switches  42  may be also provided for each of the LED strings  14 . As shown in  FIG. 6 , the switches  42  may be located between the respective first, second, third resistors  28 ,  30 ,  34  and the second ends  20  of the LED strings  14 . The switches  42  are preferably set to a normally open state so that without voltage applied thereto, no current may flow therethrough. The switches  42  may be field effect transistors, more particularly, metal oxide semiconductor field effect transistors (MOSFETs), and, more particularly, n-channel type MOSFETs. As MOSFETs, the switches  42  may be activated with positive voltage applied to gates  44  by bias lines  40 . With this arrangement, stray current is restricted from flowing into the LED strings  14 , causing uncontrolled illumination thereof. 
     As shown in  FIG. 5 , bias resistors  45  may be provided along the bias lines  44  to control the amount of voltage being applied to the current regulators  36  and the switches  42 . 
     The module  10  may be used alone or in combination with other modules  10  as a system in forming a light fixture. The first, second, and third terminals  24 ,  26 ,  32  and the positive voltage terminal  22  may be configured in various manners to allow for the boards  12  of different modules  10  to electrically couple, as well as, to allow for electrical coupling with external electrical components, e.g., via wires. With reference to  FIG. 7 , the module  10  is shown with cooperating male and female connectors  46 ,  48 . The male and female connectors  46 ,  48  are shown to be located at opposing first and second ends  47 ,  49  of the module  10 , thus, allowing for end-to-end connection with similarly-configured modules  10 . The male connector  46  is provided as a generally flat conductive element formed to slide into, and be engaged by, the female connector  48 , which may be generally U-shaped with a downward depending arm for pressing engagement against the male connector  46 . The female connector  48  is inherently biased to the closed position shown in  FIG. 7  to maintain good contact with the received male connector  46 . 
     A wire coupling module  50  may be provided having a plurality of wire-to-board connectors  52 . The wire-to-board connectors  52  may be of various configurations, including the type which make electrical connection with the wires having been pushed thereinto, such as with Wago type connectors. The wire coupling module  50  may include a plurality of the female connectors  48  corresponding to the wire-to-board connectors  52 . The female connectors  48  are electrically coupled with the wire-to-board connectors  52  to conduct therethrough electricity from the corresponding wire-to-board connectors  52 . The wire coupling module  50  may be connected to one end of the module  10  using the female connectors  48 , thereby allowing for wires to be connected to the module  10 , albeit indirectly. The wire-to-board connectors  52  should correspond, in quantity and positioning, to the positive voltage terminal  22 , and each of the terminals  24 ,  26 ,  32 , as provided. Alternatively to utilizing the wire coupling module  50 , the wire-to-board connectors  52  may be provided directly on the module  10  as any of the first, second, third terminals  24 ,  26 ,  32  and/or as the positive voltage terminal  22 . 
     As further shown in  FIG. 10 , the first, second, third terminals  24 ,  26 ,  32  and/or the positive voltage terminal  22  may be configured as pads  54  to which wires may be soldered. 
     As shown in  FIG. 11 , the module  10  may be connected with other modules  10  in forming a lighting system  56 . The modules  10  of the system  56  may be provided with various configurations (shapes, lengths) for various installations, such as, accent lighting, recessed lighting, under-cabinet lighting, and so forth. The shape of the system  56  may be configured to the requirements of the installation. For example, the module  10  may be formed with a relatively short length (e.g., 1 inch), such as including one of the LED strings  14 . Various quantities of the module  10  may be coupled together within the system  56 . A short length for the modules  10  allows for greater variation in configuration (i.e., greater number of achievable lengths). Modules  10  of different lengths may be used in combination. For example, modules  10  may be provided in lengths of 1 inch, 24 inches, and 48 inches, which may be used in various combinations. In addition, the modules  10  may be bent to define corner-pieces  58  or other directional changes to provide non-linear arrangements of the system  56 . As shown in  FIG. 11 , jumper cables  60  may be used to electrically couple a pair of adjacent modules  10  including in a non-linear fashion. As shown in  FIG. 12 , the jumper cables  60  may be connected at both ends to wire coupling modules  50 , which in turn may be connected to two of the modules  10 . Alternatively, the jumper cables  60  may be provided with the male and female connectors  46 ,  48  to connect directly to the modules  10 . The jumper cables  60  may be also soldered to the pads  54 . Optionally, a termination module  62  may be provided as an end piece for the system  56 . The termination module  62  may cover any open contacts of the ultimate module  10  of the system  56 . 
     Within the system  56 , power must be conveyed from module to module. As shown in  FIGS. 4 and 5 , output terminals, in the same quantity as the terminals ( 22 ,  24 ,  26 ,  32 ) intended for connection with the direct current source of power, may be provided which allow for the conveyance of power to the next adjacent module  10 . Thus, the positive voltage terminal  22  is connected to positive voltage output terminal  22 B; the first terminal  24  is connected to first output terminal  24 B; the second terminal  26  is connected to second output terminal  26 B; the third terminal  32  is connected to third output terminal  32 B; and, so forth, with each terminal having a corresponding output terminal. The output terminals ( 22 B,  24 B,  26 B,  32 B) of one of the modules  10  couple with input terminals ( 22 ,  24 ,  26 ,  32 ) of the adjacent module  10  utilizing the connectors described above, such as the board-to-board connectors (male and female connectors  46 ,  48 ), wire-to-board connectors  52 , and/or soldered connections utilizing the pads  54 . This allows for electrical coupling of the modules  10 . Power is caused to flow through the positive voltage terminals ( 22 ,  22 B) and through the terminals corresponding to the terminal ( 24 ,  26 ,  32 ) selected on the first module  10  connected to the source of direct current power. The output terminals ( 22 B,  24 B,  26 B,  32 B) are positioned to engage the input terminals ( 22 ,  24 ,  26 ,  32 ) in corresponding fashion, so that electrical flow is maintained on selected paths for the selected intensity. 
     It is noted that the selection of intensity of the light for the initial module  10  sets the intensity for the entire system  56 . In other words, the first module  10  in the system  56  to which is connected the direct current power source, the selection of the first, second, third terminals  24 ,  26 ,  32  on the first module  10  determines the level of light intensity for the first module  10  and for the entire system  56 . 
       FIGS. 4 and 5  show the input terminals ( 22 ,  24 ,  26 ,  32 ) and the output terminals ( 22 B,  24 B,  26 B,  32 B) being adjacent one another. This, however, is a schematic presentation. It is preferred that the input terminals ( 22 ,  24 ,  26 ,  32 ) be located adjacent the first end  47  of the module  10  while the output terminals ( 22 B,  24 B,  26 B,  32 B) are located adjacent the second end  49  of the module  10 . This facilitates end-to-end connection of the modules  10 . In addition, the first and second ends  47 ,  49  may be formed to shape-matingly engage, such as the first end  47  having a cut-out and the second end  49  having a shoulder profile shaped to be received in the cut-out to allow for greater stability in connections between the modules  10 . 
     As shown in  FIG. 13 , the module  10  or the system  56  may be mounted in one or more channel housings  66  in forming a light fixture  68 . The channel housing  66  may be provided with straight lengths and corners corresponding to the shapes of the different modules  10 , including the corner-pieces  58 . The channel housing  66  is preferably a constant cross-section extrusion (plastic or metal) having an open channel for receiving one or more of the modules  10 . Mounting flanges may be provided to protrude from the sides of the channel housing  66 . Mounting clips  70  may be provided configured for securing the light fixture  68  to a support surface. The mounting clips  70  may have upstanding spring arms  72  which may engage, e.g., snap engage, mounting channel  74 , located in the bottom of the channel housing  66 , with sufficient holding force to maintain the channel housing  66  fixed thereto. Apertured end cap  76  may be provided having an aperture  78  which allows for passage of electrical wires therethrough, for example, power supply wires  88  for coupling with the wire coupling module  50 . Solid end cap  80  may be also provided to close off the channel housing  66  at the end of the light fixture  68 . The end caps  76 ,  80  are configured to cover all open electrical contacts. Lens  82  may be secured to the channel housing  66  above the module(s)  10 . The lens  82  may be provided in various configurations, such, as shown in  FIG. 15 , as being flat, round, or square. The lens  82  may be also provided with various optics. This allows for different light patterns to be projected from the light fixture  68 . The lens  82  may be formed of glass and/or a polymeric material. The lens  82  may be spaced from the module  10  to best even out light generated thereby. For example, the lens  82  may be spaced a distance of 0.5 inches from above the module  10 . 
     In addition, as shown in  FIG. 15 , the channel housing  66  may be configured to be mounted to a secondary channel housing  84  which permits additional depth for the light fixture  68 , including space  85  for electrical components and power supply, such as a driver. The secondary channel housing  84  may have an angled shape ( 84   a ), as shown in  FIG. 15 , to provide the light fixture  68  with an angled projection. 
     As shown in  FIGS. 14A-14F , the light fixture  68  may be mounted and assembled by initially securing the mounting clips  72  to a support surface with fasteners F ( FIG. 14A ), securing thereto, by snap engagement, the mounting channel  74  of the channel housing  66  (Figure B). The module  10  is positioned within the channel housing  66  and fixed thereto, such as by rivets  86  ( FIG. 14C ). Other fasteners may be used to fix the module  10 , such as screws and/or adhesives, including double-sided tape. The lens  82  is mounted to the channel housing  66  above the module  10  ( FIG. 14D ). The module  10  may be coupled to power utilizing the wire coupling module  50  with power supply wires  88  being connected thereto extending through the apertured end cap  76  ( FIG. 14E ). The power supply wires  88  may be connected with a source of power, such as a direct current source of power ( FIG. 14F ). 
     The power supply wires  88  may convey power from a direct current power source, such as a battery or solar panel. The power supply wires  88  may also convey power from an AC/DC converter, such as a driver. As shown in  FIG. 16 , driver  92  may be utilized with the system  56  and the light fixture  68  to convert inputted alternating current to outputted direct current usable with the module(s)  10 , either alone, or in the system  56  or the light fixture  68 . A dimming module  94  may be provided along the outputted direct current to vary the voltage thereof in providing for dimming control of the module(s)  10 , relative to the set intensity.