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Cheap Lens cause IP Failures

Cheap Lens cause IP Failures

Why do we need Lens? To concentrate the light, offer a required light distribution, or decorate the light to be cooler and look advanced?

Actually, there is another function for the lens: protect the LED against the water.  This is very easy to be understood: for many outdoor lights and UFO high bay lights, the lens is the only material between the LED and water.


Let's assume that the "lamp IP failure" happens like this:

  1. In the outdoor lights factory,  QC did IP testing after all the lens be assembled on the lights, the testing result shows very good---No IP failures.
  2. After the lights been used for months. Because of heat, the lens’ shape changed, the edge becomes bending.-- Normally this bending or deformation won’t happen, but it happens if the lens material is not a good PC.

Now, Let’s do some experiments in BackMorning’s LED Lighting laboratory, to check the above image.

Step 1. Select 2 new street lights:

  1. Use good PC Lens
  2. Use cheap lens

Step 2. Let’s do IPX5 testing on Sample A & B, according to IEC 60598. Result: Pass


Step 3: Put A&B in the oven for 7 days.


Step 4. After the oven testing, let’s check the lens’ shape and do IP testing. We get below important findings:

  1. B’s lens’ shape change. A is the same as before.
  2. B failed at the IP testing, A pass.

Based on the above, we recommend the buyer and factories to pay attention to the lens material: select good suppliers, and do enough verification for the material.

The measured data of the following products has been approved by the supplier, and will be uploaded and released by Back Morning independently!

Test product category