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I recently bought some CREE LED bulbs, the kind pictured below, and while they are the same shape as glass incandescent bulbs, they seem to have some sort of cloudy and sticky rubber coating, as if the whole bulb had been dipped in silicone. What is this coating? What effects does it have?

CREE bulb

Sparr
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2 Answers2

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It's done for anti-shatter, the silicone keeps the glass shards together.

According to their product sheet, "Safety coated glass for shatter resistance provides a protective shield to safely contain the glass if the bulb should break"

It first came out being used on incandescent bulbs for mechanic's trouble lights.

Fiasco Labs
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  • But it will act like flypaper in any ceiling fixture. A protective coating on a lightbulb should not be so very sticky on its surface. I took pains - and many minutes of hard work - to peel it away from the new Cree bulb going into my ceiling fixture. I won't be buying more. –  Jan 20 '14 at 22:06
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    Acts like fly paper? I've had one for a while and I don't have any flies attracted to it – Joe Phillips Mar 17 '14 at 00:36
  • +1 Obviously I posted not seeing that you had already (a minute before?) covered the answer. A year and a half later, the truth comes out! – bib Apr 08 '15 at 21:44
  • @bib - Its all good ;^). I remember the first time I broke a shatterproof incandescent. The cage hit hard enough to dent it and pop the front open. Buh? Where's all the glass? Oh, look a floppy sock with a funky crazed liner... – Fiasco Labs Apr 09 '15 at 03:55
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At its site, Cree advertises its lighting as having safety coated glass.

It is likely that this is a plastic material that will help contain the glass envelope if it is shattered. There are similar plastic membranes in the middle of car windshields that hold the glass fragments in place in the case of an accident.

bib
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