We can offer a low cost remote phosphor solution to the purple street light phenomena that does not require replacing the LED fixture. Replacing an LED street light lamp can run in the hundreds or even thousands of dollars per lamp when the cost of labor is accounted for.
Many LED street lights around the globe are turning purple color after just few thousand hours in operation. This is a result of a color chromaticity shift caused by increased blue light leakage from the LED bulb. All white LEDs are built using a blue LED and a yellow phosphor layer coating. This technology is referred to as phosphor-converted LEDs or pcLEDs. The yellow phosphor responsible for the white light color is generally mixed in a silicone matrix and attached directly to the blue LED package. Over time, the heat generated by the high power LED package causes de-lamination or cracks to appear in the silicone layer. Maintaining a white light color requires a balance between the blue LED light and yellow-orange light produced by the phosphor layer. When de-lamination or cracks appear, the color balance changes due to increased blue light leakage.
Interestingly, the blue LED fixture and driver electronics generally remain fully functional. The problem has to do with the silicone layer in which the phosphor is encapsulated. Therefore, a solution to the purple street light problem does not require replacing the entire fixture. Replacing the fixture is a costly approach and not necessary since most of the critical components inside the lamps are still operational. If applied correctly, a remote phosphor solution could fix the purple street light problem at a fraction of the cost compared to the cost involved in replacing the entire LED fixture. Doing so can be achieved by applying a phosphor film to the inside lens or lamp cover and without removing/modifying any existing LEDs or electronics. Our remote phosphor film products can be easily customized by the user to fit inside the wide range of installed street light fixture designs.
To explore how remote phosphors can be used as a low-cost solution to the purple street light problem, contact our experts at info@phosphortech.com and provide details about your particular product and power levels. You can also complete and submit the form at this link if you are interested in a specific phosphor or related application.
Normally functioning LED street light (left). Street light after turning purple color (right)