Most of us know lumen can be used as a measure of brightness. It means the total amount of visible lights from an emitting source, such as a LED lamp, reflecting the sensitivity of human eyes to lights of different wavelengths. American National Standards Institute established a procedure for testing light output with lumen. However, data received by this means is not very precise. And due to the limitations of production workmanship, some merchandise are labeled with the higher luminous flux than its real brightness. To obtain a competitive lumen, some factories choose to sacrifice other technical advantages, such as increasing lumen at the cost of color changes.

fins heat sinkActually, this two metrics are sometimes incompatible. The red or purple lights are of low lumens due to the matter of wavelength, but the white efficiency can be very high if it has been designed with good system of heat sinks, wires, connectors and so on.

The LED market is filled with products of high lumens in accord with customers’ demands. The white efficiency is much more a business engineers concerned about.  In the long run, technical improvement may solve these problems to produce LED driving lights with high white efficiency, high lumens as well as optimal heat generation and dispersion.