Channel letters are known to those skilled in the art of making commercial signs as the most attractive and expensive form of sign lettering. Briefly, channel letters usually include a plastic or metal backing having the shape of the letter to be formed. Metal channel siding, frequently formed of aluminum with a painted or otherwise finished interior and exterior surface, is attached to and sealed to the letter backing, giving depth to the letter to be formed. Electrical lighting fixtures, such as neon tubing and mounting brackets, are attached to the letter backing. Typically, a colored, translucent plastic letter face is attached to the front edge portion of the channel side material.
As discussed above, neon lighting is typically incorporated into channel lettering systems. Neon systems are very fragile and, therefore, tend to fail and/or break during manufacture, shipping or installation. Also, such lighting systems use high voltage (e.g., between about 4,000 and about 15,000 volts) electricity to excite the neon gas within the tubing. High voltage applications have been associated with deaths by electrocution and building damage due to fire. Semiconductor lighting (e.g., light emitting diodes), that overcomes most of these drawbacks, has been used for channel lettering.
One such conventional channel lettering device attaches a light emitting diode (“LED”) system to a back of a channel letter such that the LED system emits light toward a translucent face at a front of the device. The LEDs are spaced at regular intervals (e.g., 2 inches) and are pressed into a socket. The socket is designed for a press-fit of a modified Super Flux (Piranha) package. The lead frames of the Piranha are bent 90 degrees to fit into the socket. The connection for the LED is similar to insulation displacement (“IDC”). The socket also has two IDC places for a red and black wire. This system puts all of the LEDs in parallel. Furthermore, the two part power supply (Initial (120VAC to 24VDC) and the Secondary (24VDC to ˜2.3VDC)) have two basic wiring connections. The secondary has a sense circuit, which has one LED attached for determining the voltage applied to the rest of the LEDs that are attached to the second connection.
Another conventional channel lettering device attaches to a side of the channel letter and is pointed toward the backing. The diffuse surface of the channel letter walls provides a uniform appearance. Each module has a predetermined number of LEDs electrically connected in series. Furthermore, all of the modules are daisy chained together in a parallel circuit. The LEDs are mounted on an aluminum base for heat sinking purposes.
Another conventional channel lettering device uses a plurality of surface mounted LEDs with an integral connector system.
Although these conventional LED channel lettering systems overcome some of the drawbacks associated with neon systems, other shortcomings are evident. For example, the conventional LED channel lettering systems offer only limited flexibility. More specifically, the LEDs cannot be easily set into a desired shape involving significant curves or bends (e.g., wrapped around a pole or in a very small radius (<3 inches). Furthermore, the LEDs cannot be easily moved from one lighting application to another.
The present invention contemplates an improved apparatus and method that overcomes the above-mentioned limitations and others.
In accordance with one embodiment of the present invention, an illuminated sign is disclosed. A flexible electrical power cord includes first and second parallel conductors surroundingly contained within an insulating sheath defining a constant separation distance between the parallel conductors. A plurality of light emitting diode (LED) devices are affixed to the cord. Each LED device includes an LED having a positive lead electrically communicating with the first parallel conductor and a negative lead electrically communicating with the second parallel conductor. A stencil defines a selected shape and onto which the electrical cord is arranged. Power conditioning electronics disposed away from the stencil electrically communicate with the first and second parallel conductors of the electrical power cord. The power conditioning electronics power the LED devices via the parallel conductors.
In accordance with another embodiment of the present invention, an article of manufacture is disclosed for installing a plurality of light emitting diodes (LEDs) into a channel letter housing which has at least one light-transmissive surface. A substantially rigid structure is pre-formed or formable for arrangement in the channel letter housing. A flexible cable including at least two flexible parallel conductors is arranged to support an electrical potential difference between the parallel conductors. A plurality of LEDs electrically parallel-interconnected by communication of the anode and cathode of each LED with the at least two conductors of the flexible cable. A fastener secures at least a portion of the flexible cable onto the rigid structure. A power module receives power having first characteristics and converts the received power to a supply power having second characteristics which is communicated to the at least two conductors of the flexible cable to power the plurality of parallel-interconnected LEDs.
In accordance with another embodiment of the present invention, a light emitting diode (LED) light engine is disclosed. An electrical cable includes at least two flexible electrical conductors. The electrical cable further includes a flexible, electrically insulating covering that surrounds the electrical conductors. The conductors are arranged substantially parallel with a selected separation therebetween. An LED with a plurality of electrical leads separated by the selected separation electrically contacts the electrical conductors and mechanically pierces the insulating covering to mechanically secure the LED to the electrical cable.
In accordance with another embodiment of the present invention, a light emitting diode (LED) light engine is disclosed. An electrical cable includes a positive flexible conductor connected with an associated positive source of electrical power, a negative flexible conductor connected with an associated negative source of electrical power, and an electrically insulating covering surrounding and electrically insulating the positive and negative conductors and holding the conductors separate at a selected separation distance. An LED includes positive and negative leads. A connector mechanically secures to the flexible insulating covering. The connector includes positive and negative prongs that pierce the insulating covering and electrically contact the positive and negative conductors, respectively. The connector further has the LED mounted thereon with the positive and negative leads of the LED electrically contacting the positive and negative prongs, respectively.
In accordance with another embodiment of the present invention, a method of manufacturing an LED light engine is provided. A plurality of conductive elements are insulated to form a flexible electrically insulating conductor. An LED is mechanically secured to the insulated conductive elements. Simultaneously with the mechanical securing, a plurality of leads of the LED are electrically contacted to respective ones of the conductive elements.
In accordance with yet another embodiment of the present invention, a flexible lighting device is disclosed. A flexible cable includes an electrically insulating sheath which contains positive and negative conductors electrically isolated from one another. The sheath provides a spacing between the positive and negative conductors. A plurality of light emitting diode (LED) devices are spaced apart from one another on the cable. Each of the LED devices has an LED including positive and negative leads mounted on a connector which mechanically secures the LED device to a portion of the flexible cable and electrically connects the positive and negative LED leads to the positive and negative conductors through positive and negative conductive piercing members which pierce the sheath to make electrical contact with the respective conductors.
In accordance with still yet another embodiment of the present invention, a light emitting diode (LED) lighting apparatus is disclosed. A flexible electrical cable includes an anode wire and a cathode wire arranged in an electrically isolating sheath. A plurality of LED devices are spaced apart along the cable and mechanically and electrically connect therewith. Each LED device includes an LED having at least one anode lead and at least one cathode lead. Each LED device further includes a connector with an LED socket that receives the anode and cathode leads. The LED socket mechanically retains the LED. The connector further includes a first electrically conductive path between the anode lead and the anode wire, and a second electrically conductive path between the cathode lead and the cathode wire. The first and second conductive paths displace portions of the cable sheath.
One advantage of the present invention resides in providing a channel lettering having a reduced number of parts compared with past systems.
Another advantage of the present invention resides in the use of parallel interconnection of the LEDs which reduces the likelihood that a failed LED will adversely affect performance of other LEDs on the same electrical circuit.
Another advantage of the present invention resides in the locating of the conditioning electronics away from the channel lettering, e.g. in a secure and weatherproofed interior location.
Another advantage of the present invention is the avoidance of soldering connections in the flexible LED light engine.
Yet another advantage of the present invention is that it allows for coupling in the electrical power anywhere along the flexible LED light engine.
Still yet another advantage of the present invention resides in its modular nature which allows part or all of a channel lettering to be constructed on-site in a customized manner.
Numerous advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description.
The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating a preferred embodiment and are not to be construed as limiting the invention.
With reference to
Preferably, the conductor 12 includes two conductive elements 16a, 16b. Furthermore, each of the conductive elements 16a, 16b is preferably sized to be about 14 gauge. Additionally, each of the conductive elements 16a, 16b is preferably stranded and includes a plurality of strands 18 (e.g., seven strands).
The LED light engine 10 also includes an LED 20, which electrically contacts the conductive elements 16 and is mechanically secured to the insulating covering 14. More specifically, with reference to
With reference to
Preferably, the LED 20 is secured to the conductor 12 when the conductor 12 is positioned flat (i.e., when the conductive elements 16a, 16b run in a common substantially horizontal plane which is above a horizontal surface).
Optionally, the conductor 12 includes two dips (grooves) 24a, 24b in the insulating covering 14. The dips 24a, 24b are positioned substantially above the respective conductive elements 16a, 16b, respectively. Before the LED 20 is secured to the conductor 12, the leads 22 are placed in the dips 24a, 24b and, therefore, aligned over the conductive elements 16a, 16b, respectively. Then, after being aligned in the dips 24, the leads 22 are passed through the insulating covering 14 and inserted into the conductive elements 16.
With reference to
Optionally, a hole 60 is formed in one of the sections 54b through which a means for securing (e.g., a fastener such as a screw, nail, bolt, etc.) is inserted for securing the connector 54 to a wall or other support means. For example, the connector 54 may be secured to a wall of a channel lettering housing (see
The connector section 54b includes a plurality of electrical contacts 62 that, once the sections 54a, 54b are snapped together, electrically contact the LED 50. As is discussed below, the contacts 62, along with the sections 54a, 54b, are used for mechanically securing the connector 54 to the conductor 52. A plurality of pairs of the contacts 62 electrically communicate with each other. More specifically, the contacts 62a, 62c electrically communicate with each other while the contacts 62b, 62d electrically communicate with each other. In a suitable embodiment, the electrical communication is a direct electrical contacting, i.e. the contacts 62a, 62c are electrically continuous and the contacts 62b, 62d are electrically continuous.
One set of the contacts 62a, 62c, for example, is electrically connected to a positive source of electrical power while the other set of the contacts 62b, 62d, for example, is electrically connected to a negative source of the electrical power. In this manner, the anode of the LED 50 is in direct electrical contact with the positive source while the cathode of the LED 50 is in direct electrical contact with the negative source of electrical power. The set of contacts 62a, 62c is electrically isolated from the set of contacts 62b, 62d. Furthermore, the electrical contacts 62 are V-shaped and sized to accept conductive elements 56a, 56b within the respective V-shaped spaces. More specifically, the tips of the V-shaped electrical contacts 62 are sharp and formed for displacing (piercing) the insulative coverings around the conductive elements 56a, 56b.
Although only two of the contacts 62a, 62b (or, alternatively, 62c, 62d) is necessary, the connector 54 preferably includes two pairs of the contacts 62 to offer added stability to the mechanical connection between the connector 54 and the conductor 52.
After displacing the insulative coverings, the conductive elements 56a, 56b are passed into the V-shaped spaces of the electrical contacts 62. As the conductive elements 56a, 56b are passed into the V-shaped spaces, the strands within the conductive elements 56 are wedged into the vertex of the “V.” In this manner, a secure electrical contact is made between the conductive elements 56 and the respective electrical contacts 62. Furthermore, the strands are squeezed such that a shape of the conductor changes, for example, from round to oval. Also, as the strands are squeezed, spaces between the strands is reduced such that an overall size (e.g., diameter or circumference) of the respective conductive element 56a, 56b is reduced, for example, to a size of an “un-squeezed” three strand connector.
Preferably, the connector 54 is secured to the conductor 52 when the conductor 52 is positioned on-edge (i.e., when the conductive elements 56a, 56b run in substantially parallel horizontal planes above a substantially horizontal surface).
It is to be understood that although the embodiments have been described with reference to a single LED 20 (
Furthermore, if a plurality of the LEDs 20 are secured to the conductor 12 (
With reference to
The conductors 72, 74 are aligned parallel and on-edge with respect to one another. Then, the splice connector 70 is secured around both of the conductors 72, 74. In this manner, respective first conductive elements 72a, 74a are mechanically and electrically secured to one another; similarly, respective second conductive elements 72b, 74b are mechanically and electrically secured to one another.
With respect to
With reference to
With continuing reference to
Because the LED devices 102 are spaced apart along the flexible electrical cable 100, for example at two-inch spacings, the intervening cable portions between the LED devices 102 can bend to define a channel letter shape or other selected pattern, such as the letter “E” formed by the light engine 90 in
The second region 110 advantageously employs a mechanical connection which also effectuates the electrical connections of the LED 104 to the conductors 112, 114 in a manner similar to that described previously, e.g. using electrical leads 62 (see
With continuing reference to
With particular reference to
With particular reference to
The first region 106 includes a socket that receives the LED 104 with the light-emitting surface (i.e., the surface with the encapsulant 132 disposed thereon) facing away from the connector 108 and the LED leads 130 inserting into the socket. The connector 108 includes a first section 140 with the first region 106 that provides the LED mount or socket, and a second section 142 that connects with the first section 140 in a clamping or snapping fashion. The second region 110 including the clamp, mechanical snap connection, or the like is defined by the connection of the two sections 140, 142 about a portion of the flexible electrical cable 100.
With continuing reference to
Assembly of the first section 140 of the connector 108 includes inserting the prongs 144P, 144N into the first section 140, and inserting the LED 104 into the socket of the first region 106 so that the LED leads 130 compressively fit into the slots 146 of the prongs 144 to effectuate electrical contact therewith. In a preferred embodiment, the first section 140 is a molded body of plastic or another electrically insulating material, the prongs 144 are formed from sheet metal or another substantially planar electrically conductive material, and the LED 104 is a pre-packaged LED of a type known to the art, e.g. an electroluminescent semiconducting element arranged in a P4 (piranha) package with suitable epoxy or other encapsulant. It will be appreciated that a significant advantage of the connectorized LED device 102 is that assembly thereof involves no soldering steps.
With continuing reference to
It will be appreciated that the snapping connection of the first and second sections 140, 142 about the cable 100 effectuates both a mechanical connection of the LED device 102 to the cable 100 as well as a simultaneous electrical connection of the positive and negative (anode and cathode) terminals of the LED 104 via the prongs 144P, 144N to the conductors 112, 114 that supply electrical power. The electrical connection does not include auxiliary electrical components, such as resistors or the like, and does not include soldering. Hence the LED device 102 includes few component parts in the channel lettering which reduces the likelihood of device failure. However, it is also contemplated to include resistive or other circuit elements in the connector 108 to perform selected power conditioning or other electrical operations.
Preferably, the conductors 112, 114, the prongs 144P, 144N, and the LED leads 130 are formed from substantially similar metals to reduce galvanic corrosion at the electrically contacting interfaces, or are coated with a conductive coating that reduces galvanic corrosion at the interfaces. In a suitable embodiment, the conductors 112, 114, the prongs 144P, 144N, and the LED leads 130 are each coated with a conductive coating of the same type, which ensures that galvanic corrosion at the contacting surfaces is minimized. Particularly in the case of high power LED devices 102, embodiments that employed contacting surfaces with mismatched compositions typically experienced significant detrimental galvanic corrosion at the contacting surfaces.
With reference to
With reference to
With continuing reference to
With reference to
In a variation of the above installation process, the LEDs 104 are installed on the connectors 108 at the factory, but the LED devices 102 are snapped onto the cable 100 at selected locations along the cable 100 at the installation site. This approach is more labor-intensive at the installation site, but provides maximum flexibility in the selection and spacing of the LED devices 102 along the cord 100. Such a modular system can allow the end-user to select the colors of the LEDs 104 to create a custom multi-color flexible LED light source 90.
In yet another variation, the connector 108 is optionally omitted similarly to the previously-described embodiment of
With continuing reference to
Each power supply 210, 220 is arranged away from the illuminated channel lettering “TEXT”, for example in the interior of an associated building, and includes conditioning electronics for converting building power (e.g., 120V a.c. in the United States, or 220V a.c. in Europe) to power suitable for driving the LED light sources of the channel lettering. Since a parallel electrical connection is used in the light engine 90, the output power is low voltage, corresponding to the driving voltage of a single LED, and so a low voltage power supply can be employed. In a preferred embodiment, the power supplies 210, 220 are class II power supplies which have output power limited to 5 amperes and 30 volts. Class II power supplies are relatively safe due to the low voltages and currents produced thereby, and the output lines 212, 214, 222, 224 are typically not required by electrical codes to be arranged in safety conduits.
Of course, each power supply can include a different number of power output lines, e.g. one, three, or more power output lines. Each power output line provides a selectable electrical output power, for example as monitored by the meters 226. In a preferred embodiment, the power delivered to each power output line is individually controllable using a knob 228 or other control input. This permits balancing the light intensity of the letters, e.g. of the letters “T”, “E”, “X”, and “T”, to obtain a uniformly lit sign “TEXT”.
The invention has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
This application claims priority from U.S. Non-provisional patent application Ser. No. 09/866,581 filed on May 25, 2001.
Filing Document | Filing Date | Country | Kind |
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PCT/US02/16749 | 5/24/2002 | WO |
Number | Date | Country | |
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Parent | 09866581 | May 2001 | US |
Child | 10484674 | Sep 2004 | US |