1. Field of the Invention
The present invention relates generally to light emitting diode (LED) lighting devices and more particularly to LED lighting modules having heat transfer properties that improve the efficiency and performance of LEDs.
2. Description of the Related Art
Most lighting applications utilize incandescent or gas-filled bulbs, particularly lighting applications that require more than a low level of illumination. Such bulbs typically do not have long operating lifetimes and thus require frequent replacement. Gas-filled tubes, such as fluorescent or neon tubes, may have longer lifetimes, but operate using dangerously high voltages and are relatively expensive. Further, both bulbs and gas-filled tubes consume substantial amounts of power.
In contrast, light emitting diodes (LEDs) are relatively inexpensive, operate at low voltage, and have long operating lifetimes. Additionally, LEDs consume relatively little power and are relatively compact. These attributes make LEDs particularly desirable and well suited for many applications. However, one limitation of LEDs is that they typically do not provide sufficient brightness for applications that need more than low level illumination.
Although it is known that the brightness of the light emitted by an LED can be increased by increasing the electrical current supplied to the LED, increased current also increases the junction temperature of the LED. Increased junction temperature may reduce the efficiency and the lifetime of the LED. For example, it has been noted that for every 10xc2x0 C. increase in temperature above a specified temperature, the operating lifetime of silicone and gallium arsenide drops by a factor of 2.5-3. LEDs are often constructed of semiconductor materials that share many similar properties with silicone and gallium arsenide.
Another factor in the use of LEDs is that, in most systems, a series of LEDs must be connected together and mounted on a surface. Such connection and mounting is typically a time consuming, laborious process.
Accordingly, there is a need in the art for a convenient and efficient arrangement for mounting LEDs on a surface. There is also a need in the art for lighting systems utilizing LEDs that provide illumination at levels which are more comparable to those of incandescent bulbs and gas-filled tubes.
The present lighting system is directed, inter alia, to a mounting arrangement for LEDs, which in the preferred embodiment may be adapted to allow for increased LED brightness.
In accordance with one embodiment, a lighting system is provided comprising a plurality of lighting modules adapted to be mounted on a surface of a heat conductive member. Each module comprises a plurality of light emitting diodes (LEDs) and a plurality of electrically conductive contacts. Each of the LEDs electrically communicates with at least one of the contacts in a manner so that the LEDs are configured in a series array between opposing first and second edges of the module. A dielectric layer is provided and has a first side and a second side. The contacts are connected to the first side of the dielectric layer. Each of the modules further includes an adhesive layer adapted to fasten the module to a surface of a heat conductive member such that heat from the module is drawn into the heat conductive member through the adhesive.
In accordance with another embodiment, A lighting system has a plurality of lighting modules adapted to be mounted on a surface of a heat conductive member. Each module comprises a plurality of light emitting diodes (LEDs), a plurality of electrically conductive contacts, and a dielectric layer supporting the contacts. Each of the LEDs electrically communicates with at least one of the contacts in a manner so that the LEDs are configured in a series array on the module, The modules are electrically interconnected so that the series array of each module is electrically parallel to the series array of others of the modules. Further, wherein the interconnected modules are arranged in a dispenser such that a selected portion of the interconnected modules may be successively dispensed from the dispenser and removed therefrom.
In accordance with yet another embodiment, the invention provides a method of mounting a plurality of lighting modules on a heat conducting surface so that heat from the modules is drawn into the heat conductive surface. A plurality of lighting modules are successively electrically interconnected with one another. Each module comprises a plurality of LEDs, a plurality of electrically conductive contacts, and a dielectric layer having a first side and a second side. Each of the LEDs electrically communicates with at least one of the contacts in a manner so that the LEDs are configured in a series array. The contacts are connected to the first side of the dielectric layer. The series array of each module is connected in an electrically parallel fashion with the series arrays of the other modules. A dispenser is provided and is configured to contain the plurality of interconnected modules. Successive modules are drawn from the dispenser and are successively mounted to the heat conductive surface using a thermally conductive tape.
In accordance with still another embodiment, a method of manufacturing a lighting system is provided. A plurality of LED modules are provided, each having a plurality of LEDs arranged in a serial array. A tape layer is applied to one side of each LED module so that the tape extends outwardly beyond opposing edges of the module. A linear chain of LED modules is formed by electrically connecting adjacent modules using flexible conductors. The linear chain of modules is compactly packaged by winding the modules in a coil or folding the modules in a serpentine pattern.
For purposes of summarizing the present mounting arrangement and the advantages achieved over the prior art, certain advantages have been described herein above. Of course, it is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.
All of these embodiments are intended to be within the scope of the invention. These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed.