Abstract:
A method and device for replacing a fluorescent tube lamp with an LED lamp. The LED lamp includes an elongated electrical assembly having ends terminating in first and second electrical connectors, and a plurality of LEDs mounted to the elongated electrical assembly. Mounting adaptors connect with the first and second electrical connectors, and have protruding pins to connect with conventional lamp socket connectors. The mounting adaptors have rotating connectors for connecting with the first and second electrical connectors of the LED lamp, so that the LED lamp orientation can be rotated after the LED lamp is fully mounted to the lamp socket connectors.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/789,673, filed Apr. 5, 2006, and entitled Retrofitting of Fluorescent Tubes with Light-Emitting Diode (LED) Modules for Various Signs and Lighting Applications. 

   FIELD OF THE INVENTION 
   The present invention relates to the design and the installation of retrofit Light Emitting Diode (LED) modules to replace existing fluorescent tube lamps typically found in street lights, parking lot lights, and various other lighting applications. More particularly, the present invention relates to a method and apparatus for installing a retrofit LED module in a conventional fluorescent tube lamp housing. 
   BACKGROUND OF THE INVENTION 
   Light emitting diodes (LEDs) have been widely used in many applications to replace conventional incandescent lamps, fluorescent lamps, neon tube lamps and fiber optic lights. LEDs consume much less electrical power, are far more reliable, and exhibit much longer lifetimes, than their conventional counterparts. As a result, LEDs have been configured to replace conventional light sources for many applications. For example, LED lamps have been. developed to replace screw-in incandescent light bulbs for traffic signals (as shown in U.S. Pat. No. 6,036,336), and exit signs (as shown in U.S. Pat. Nos. 5,416,679, 5,459,955, 5,526,236, 5,688,042, 5,949,347). In each case, the LEDs are mounted onto a lamp housing having a conventional threaded electrical connector that engages with the threaded socket connector in the traffic signal lamp or exit sign. Thus, retrofitting the traffic signal and exit signs simply involves unscrewing the conventional lamp and screwing in the LED lamp. 
   Retrofitting with LED lamps the vast numbers of backlit commercial and street name signs, which utilize fluorescent lighting, is more problematic. These signs typically include a housing containing one or more fluorescent tube lamps, and one or more translucent face plates (sidewalls) that are back-illuminated by the fluorescent lamp(s) (i.e. to form characters, designs, symbols, etc.).  FIGS. 1A and 1B  illustrate a conventional backlit street name sign, which includes a housing  1 , a pair of fluorescent tube lamps  2  and a pair of opposing translucent face plates  3  that indicate a street name. Each of the fluorescent tube lamps  2  are connected to and suspended by a pair of electrical connectors  4 , which are well known in the art. Connectors  4  have receptacles that accept and make electrical connections with a pair of standard electrical pins protruding from each end of the fluorescent tube lamp  2 . Connectors  4  physically support the fluorescent tube lamp by the pins, as well as apply an operating voltage across them. The face plates  3  are angled slightly downwardly for better viewing from below.  FIGS. 2A and 2B  illustrate a conventional backlit commercial sign, where there is only a single translucent face plate  3  (which is not angled downwardly), and three fluorescent tube lamps  2  for illumination. 
   Replacing the short-lifespan fluorescent tube lamps in conventional backlit commercial and street name signs can be difficult, because such signs are typically elevated and inaccessible, disposed over roadways, and/or hard to open. What is worse is that there is no standard size for such signs, for the fluorescent tube lamps  2  used therein, and for the spacing between opposing electrical connectors  4 . Thus, designing an LED lamp retrofit that fits a wide variety of such signs, that evenly and sufficiently illuminates such signs, and that is easy to install without the need for special tools, has been difficult. Adding to that difficulty is the fact that many such signs are suspended in a way where the sign rocks, vibrates and shakes in the wind. 
   There is a need for a versatile LED lamp design for retrofitting conventional backlit commercial and street name signs that is easy to install and fits in a variety of sign sizes and configurations. 
   SUMMARY OF THE INVENTION 
   The present invention solves the aforementioned problems by providing a method and apparatus for installing a retrofit LED lamp module in a housing designed for fluorescent tube lamps. 
   An LED lamp, for use in a housing designed for fluorescent tube lights, includes an elongated electrical assembly having a first end terminating in a first electrical connector and a second end terminating in a second electrical connector, a plurality of LEDs mounted to the elongated electrical assembly, a first mounting adaptor having a first end electrically engagable with the first electrical connector and a second end terminating in an electrical connector having two protruding pins, and a second mounting adaptor having a first end electrically engagable with the second electrical connector and a second end terminating in an electrical connector having two protruding pins. 
   A method for retrofitting a fluorescent lamp (containing a fluorescent tube lamp connected between first and second socket connectors) includes removing the fluorescent tube lamp from the first and second socket connectors, and connecting an LED lamp to the first and second socket connectors. The LED lamp includes an elongated electrical assembly having a first end terminating in a first electrical connector and a second end terminating in a second electrical connector, a plurality of LEDs mounted to the elongated electrical assembly, a first mounting adaptor having a first end electrically engagable with the first electrical connector and a second end terminating in an electrical connector having two protruding pins, and a second mounting adaptor having a first end electrically engagable with the second electrical connector and a second end terminating in an electrical connector having two protruding pins. The connecting of the LED lamp to the first and second socket connectors includes connecting the two protruding pins of the first mounting adaptor to the first socket connector and connecting the two protruding pins of the second mounting adaptor to the second socket connector. 
   Other objects and features of the present invention will become apparent by a review of the specification, claims and appended figures. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a partially broken away side view of a conventional backlit street name sign. 
       FIG. 1B  is a cross-section view of the conventional backlit street name in  FIG. 1A . 
       FIG. 2A  is a partially broken away side view of a conventional backlit commercial sign. 
       FIG. 2B  is a side cross-section view of the conventional backlit commercial sign in  FIG. 2A . 
       FIG. 3  is a schematic of an LED module according to an embodiment of the present invention. 
       FIG. 4A  is schematic of a mounting adaptor with extension wires within the coil and spacer of the mounting adaptor. 
       FIG. 4B  is schematic of a mounting adaptor with extension wires outside the coil and spacer of the mounting adaptor. 
       FIG. 5A  is a cross section view of an LED tube, wherein LEDs are mounted on only one side of an electrical assembly. 
       FIG. 5B  is a cross section view of an LED tube, wherein LEDs are mounted on each of two surfaces of an electrical assembly. 
       FIG. 5C  is a cross section view of an LED tube, wherein LEDs are mounted onto an electrical assembly having a triangular configuration. 
       FIG. 5D  is a cross section view of an LED tube, wherein LEDs are mounted onto an electrical assembly having a square configuration. 
       FIG. 5E  is a cross section view of an LED tube, wherein LEDs are mounted onto an electrical assembly having a trapezoidal configuration. 
       FIG. 5F  is a cross section view of an LED tube, wherein LEDs are mounted onto an electrical assembly having a hexagon configuration. 
       FIG. 5G  is a cross section view of an LED tube, wherein LEDs are mounted onto an electrical assembly having two surfaces, and wherein the LEDs are partially angled towards each other. 
       FIG. 5H  is a cross section view of an LED tube, wherein LEDs are mounted onto an electrical assembly having a circular configuration. 
       FIG. 5I  is a cross section view of an LED tube, wherein LEDs are mounted onto an electrical assembly having three surfaces, and wherein the LEDs are partially angled towards each other. 
       FIG. 5J  is a cross section view of an LED tube, wherein LEDs are mounted onto an electrical assembly having a semi-circle configuration. 
       FIG. 6A  is a front-view schematic of a vertical mounting support for the LED module of the present invention. 
       FIG. 6B  is a side-view schematic of a vertical mounting support for the LED module of the present invention. 
       FIG. 7  is a side view of the mounting mechanism for the LED module of the present invention. 
       FIG. 8A  is front-view schematic of an installed LED module according to an embodiment of the present invention. 
       FIG. 8B  is side-view schematic of an installed LED module according to an embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention relates to the design and the installation of retrofit LED modules to replace existing fluorescent tube lamps. Moreover, the present invention provides a method and apparatus for installing a retrofit LED lamp module in a housing designed for fluorescent tube lamps. 
   In  FIG. 3 , a schematic of an LED module  100  according to an embodiment of the present invention is provided. As illustrated, LED module  100  includes a plurality of LEDs  111  mounted onto an elongated electrical assembly  110  (e.g. a printed circuit board, a plurality of electrical receptacles, etc.), and preferably housed within a translucent LED tube  112 . On both ends, LED module  100  includes bi-pin connectors  114 , which allow LED module  100  to electrically connect to mounting adaptors  120  via bi-pin holes  122 . In a preferred embodiment, each mounting adaptor  120  further comprises bi-pin connectors  124 , which allow each adaptor  120  to electrically connect to a conventional fluorescent tube socket  200 . Conventional fluorescent tube sockets are well known, and include holes or channels for receiving and making electrical contact with bi-pin connectors. 
   Mounting adaptor  120  is designed to facilitate the installation of the LED retrofit tube onto existing fluorescent tube lighting fixtures. In  FIGS. 4A and 4B , schematics of a mounting adaptor  120  according to embodiments of the present invention are provided. As illustrated, mounting adaptor  120  includes a housing  129 , a rotatable bi-pin socket  123 , extension wires  121 , tube spacer  126 , coil  128 , and bi-pin connector  124 . Optional rotation threads  125  can be included on the rotatable pin socket  123  and mounting adaptor housing  129  for adjusting the angular position of rotatable pin socket  123  relative to bi-pin connector  124 . It should be further appreciated that the placement of extension wires  121  may also vary. For example, in the embodiment of  FIG. 4A , extension wires  121  are located within the coil  128  and spacer  126  of mounting adaptor  120 . In  FIG. 4B , however, an alternative embodiment is provided, wherein extension wires  121  are located outside the coil  128  and spacer  126 . 
   In a preferred embodiment, the insertion of mounting adaptor  120  into an existing fluorescent tube socket  200  allows for the orientation of LED module  100  to be easily adjusted within a conventional fluorescent tube lamp housing  1  via rotatable bi-pin socket  123 . Namely, bi-pin connectors  124  will serve the equivalent function of bi-pin connectors on conventional fluorescent tube lamps, while coils  128  provide the necessary force between LED module  100  and mounting adaptor  120  so as to facilitate installation. Moreover, after installation of LED module  100  is complete, and wherein the desired orientation is set, pressure from each compressed coil  128  provides the necessary frictional force to firmly hold LED module  100  in place and to keep the orientation of the LED module  100  fixed. Optional rotation threads  125  can lack any inclination, whereby rotating pin socket  123  simply causes it to spin in place. Alternately, the rotation threads  125  can be inclined, whereby rotation of the pin socket  123  adjusts the distance between the rotatable pin socket  123  and bi-pin connector  124  to custom fit the LED lamp to the lamp fixture. 
   To retrofit a conventional sign, its housing if any is opened and the fluorescent tube lamp(s) therein are removed from sockets  200 . A mounting adaptor  120  is inserted into each of the sockets  200  (i.e. pins  124  are inserted into socket  200 ), and LED module  100  is inserted into the mounting adaptors  120  (i.e. pins  114  are inserted into pin holes  122 ). It should be understood that the LED module  100  could be connected to the mounting adaptors  120  before or after the mounting adaptors  120  are connected to the sockets  200 . Then, the LED module  100  is rotated to its desired rotational position (which possibly could be used to adjust the overall length of LED module  100  and mounting adaptors  120  between sockets  200 ), where the compressed coils  128  maintain this rotational position thereafter. The electrical connection is automatically made to supply the operating voltage to from the sockets  200 , through the mounting adaptors  120 , and to the LED module  100 . The LED module preferably includes an internal power supply  116  that transforms the operating voltage from the sockets  200  to an operating voltage appropriate to the LEDs  111 . Alternately, wires  118  extending from the internal power supply  116  could be used power the LED module  100  independent from the sockets  200  (as shown in  FIG. 3 ), whereby sockets  200  and mounting adaptors  120  simply provide mechanical support to the pins  114  of LED module  100 . It is also possible to make power supply  116  external to the LED module  100 . 
   It should also be appreciated that LEDs  111  may be mounted onto electrical assembly  110  in a variety of ways. Several examples of such configurations are provided in  FIGS. 5A-5J . As illustrated, some of these configurations include configurations in which electrical assembly  110  comprises a single surface, a plurality of surfaces, a curved surface, and/or surfaces configured in particular shapes. 
   Depending on the length and the weight of the particular LED module  100  used, a special mechanical support structure might be necessary. Some street name signs, for example, because of their size, require mechanical support for there to be an adequate retrofit. In  FIGS. 6A and 6B , exemplary schematics of such supports are provided. As illustrated, vertical support  300  comprises a top mount  310 , a bottom mount  320 , and an adjustable tube holder  360 . In a preferred embodiment, adjustable tube holder  360  is used to support and secure LED module  100 , wherein tube holder  360  is secured with position locking nuts  350  by inserting threads  340  into holes  330 , as shown. 
   In applications requiring mechanical support a mounting mechanism  400  may be utilized as illustrated in  FIG. 7 . The mounting mechanism  400  includes a mounting member  430  either rigidly connected to or integrally formed as part of one of the support arms  500 , a pair of scissor arms  410 , a pair of adjustment screws  412 , and a tightening screw  414 . The scissor arms  410  are preferably S-shaped, and each includes an upper portion  410   a , a mid-portion  410   b , a lower mid portion  410   c , and a lower portion  410   d . The scissor arm mid portions  410   b  are rotatably connected together by a bolt  416  that extends through a vertical slot  418  formed in the mounting member  430 . For each scissor arm  410 , a bolt  420  extends from its lower mid-portion  410   c  and through a horizontal slot  422  formed in the mounting member  430 . Each of the adjustment screws  412  is threaded through the lower portion  410   d  of one of the scissor arms  410 , and terminates in an engagement surface  413 . In the preferred embodiment, each adjustment screw  412  includes an engagement block of material  424  conducive to forming a friction fit (e.g. compressible or course materials, etc), with the engagement surface  413  at the end of the engagement block  424 . The tightening screw  414  is threaded through one of the scissor arm upper portions  410   a , and is rotatably engaged with the other scissor arm upper portion  410   a . Each of the screws  412 / 414  includes a conventional adjustment end (Phillips, flat blade, Allen key, etc.) for rotation thereof, thus allowing the LED module  100  to be installed with no special tools (i.e. nothing more than just a screw driver or Allen key). 
   To retrofit a conventional backlit sign mounting mechanism  400 , its housing is opened and the fluorescent tube lamps therein are removed. The adjustment screws  412  of the LED module(s) to be inserted inside the sign are adjusted so that the engagement surfaces  413  for each pair of adjustment screws  412  are separated slightly less than the interior depth of the sign&#39;s housing at its base. After the LED module is placed inside the sign housing, each of the mounting mechanisms are operated by rotating its tightening screw  414  to separate the scissor arm upper portions  410   a  from each other, which also separates the lower portions  410   d  from each other as well, thus driving the engagement surfaces  413  away from each other and against the sign&#39;s sidewalls to form a secure friction fit there between. As the tightening screw  414  is adjusted, the bolts  416 / 420  slide in slots  418 / 422  to accommodate the movement of the scissor arms  410 , while minimizing the vertical movement of the mounting member  430  during installation. Bolts  416 / 420  secure the scissor arms to the mounting member  430 , to ensure support arm  500  (which is used to support the LED module  100 ) cannot move relative to the sign&#39;s housing once installation is complete. The minimum sign depth compatible with the mounting mechanism is dictated mainly by the sizes of the mounting member  430  and scissor arms  410 , and the maximum sign depth compatible with the mounting mechanism  400  is dictated mainly by the length of the adjustment screws  412  (i.e. how far the engagement surfaces  413  can be separated). Thus, a single sized mounting mechanism  400  can be compatible with a very large range of sign depths. Shorter or longer adjustment screws  412  can be swapped in/out of scissor arms  410  to vary the range of compatible sign depths even further. Front and side view schematics of an installed LED module  100  according to an embodiment of the present invention are provided in  FIGS. 8A and 8B , respectively. 
   Once the LED module  100  is affixed to the sign housing using the mounting mechanism  400 , power supply  116  is electrically connected to the sign&#39;s electrical supply. As discussed previously, this can be done by hard wiring power supply  116  directly to LED module  100 . Within such embodiment, if additional space is needed, socket  200  may be removed from the sign. Alternatively, power supply  116  can obtain power directly from socket  200  via power cord  118 , which negates the need for any hardwiring. 
   It is to be understood that the present invention is not limited to the embodiment(s) described above and illustrated herein, but encompasses any and all variations falling within the scope of the appended claims. For example, as is apparent from the claims and specification, not all method steps need be performed in the exact order illustrated or claimed, but rather in any order that achieves the retrofit of LED lamps within conventional fluorescent lamp housings.