A luminaire is a system for producing, controlling, and/or distributing light for illumination. For example, a luminaire can include a system that outputs or distributes light into an environment, thereby allowing certain items in that environment to be visible. Luminaires are often referred to as “light fixtures”.
A recessed light fixture is a light fixture that is installed in a hollow opening in a ceiling or other surface. A typical recessed light fixture includes hanger bars fastened to spaced-apart ceiling supports or joists. A plaster frame extends between the hanger bars and includes an aperture configured to receive a lamp housing or “can” fixture.
Traditional recessed light fixtures include a lamp socket coupled to the plaster frame and/or the can fixture. The lamp socket receives an incandescent lamp or compact fluorescent lamp (“CFL”) discussed above. As is well known in the art, the traditional lamp screws into the lamp socket to complete an electrical connection between a power source and the lamp.
Increasingly, lighting manufacturers are being driven to produce energy efficient alternatives to incandescent lamps. One such alternative was the CFL discussed above. CFLs fit in existing incandescent lamp sockets and generally use less power to emit the same amount of visible light as incandescent lamps. However, CFLs include mercury, which complicates disposal of the CFLs and raises environmental concerns.
Another mercury-free alternative to incandescent lamps is the light emitting diode (“LED”). LEDs are solid state lighting devices that have higher energy efficiency and longevity than both incandescent lamps and CFLs. However, LEDs do not fit in existing incandescent lamp sockets and generally require complex electrical and thermal management systems. Therefore, traditional recessed light fixtures have not used LED light sources. Furthermore, traditional light fixtures typically use insulation detectors in new construction and retrofit applications. Insulation Detectors are thermal switches with directly heated bi-metals, and are calibrated such that when covered with one inch of insulation, sufficient heat is produced to open the switch and interrupt power to the fixture. However, the insulation protectors are not typically universal voltage, for example, they may not able to receive two different line voltages, and therefore may require two separate housings for various voltage applications. In some new construction applications, thermal protectors are placed on the housings of the light fixtures for thermal management. Placing the thermal protectors on the housings protect the housing and its surroundings by limiting the temperature of the housing. However, thermal protectors on the housing of the light fixtures have not been successful to date in thermal protection, since the LED modules may not radiate enough heat to the housing to trip a housing mounted thermal protector, even if a component of the LED module, such as the driver, exceeds its thermal limit. For example, if the thermal protector is mounted to a lower side of the housing, and the orientation of the LED module is such that the driver is far from the thermal protector, the thermal protector may not trip before the driver reaches its thermal limit.