Understanding LED Thermal Management
LEDs are known as solid state technology. This means no glass bulbs, gases, mercury, or filament are used in the lamp. LED light is produced through a highly efficient process of passing electrical energy through solid components which converts a large majority of that energy into light. This process produces heat, which is transferred into the LED itself and into the components onto which the LED is mounted. While the amount of heat produced is just a fraction of that emitted by older technologies, it is still essential that this transfer occurs quickly and completely since excess heat will reduce the life of the LED.
For the reasons stated above, one of the key challenges faced by the LED lighting industry is thermal management. An LED that has been exposed to high heat will typically lose efficiency and have diminished light output. For this reason, most LEDs and their accompanying luminaires are equipped with high-performance heat sinks capable of removing the heat generated by LEDs.
Damaging Effects of Excess Heat on LED Lights
- Temporary Reduction of Light Output. A single occurrence of excess heat - light level will recover when heat is removed.
- Cumulative Reduction of Light Output. Gradual (but permanent) reduction of light output over time when LED is subjected to multiple occasions of overheating.
- Color Changes. These result from the gradual degradation of the phosphor layer (responsible for converting LED's purple color to warm white). Color changes tend to shift towards blue, but may involve off-colors (e.g green, pink, etc.)
- Changes to LED Driver Performance. The driver is responsible for changing the incoming AC current to a DC current that flows through the LED chip. Other driver components are responsible for conditioning the current. All these components are heat-sensitive and are subject to damage. Such damage can result in diminished light output, flickering, and catastrophic failure.
Techniques to Better Transfer Heat
- Internal Transfer Components. All VOLT® LED fixtures and lamps start transferring heat from where it is generated - at the LED diode. The diode sits on a circuit board or heat sink that draws heat away from the sensitive diode. The heat then travels from these boards and sinks at every contact point.
- External Heat Sinks. All VOLT® LED fixtures have heat sinks in various shapes and configurations designed to provide enough surface area to transfer sufficient heat so the internal LED temperature does not exceed its specified limits.
- Use of Heat Tolerant LEDs. In cases where heat transfer is a greater challenge (such as with replaceable LED lamps), engineers utilize LEDs specifically designed to tolerate levels of heat that may be generated. In addition, the current that supplies these LEDs is reduced so less heat is produced.
In conclusion, professionals can trust that VOLT® LED products will perform optimally year after year. This is accomplished through the skilled application of heat transfer strategies - engineered and sourced by the VOLT® Product Development Team.