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remote control light

(I'm having difficulty zeroing in on this in web/Usenet searches, because the common words lead to other subjects.)

I have a Radio Shack 4-in-1 remote control for the tv, with a button that lights up the keys, for night use. However, there is something now wrong with it. Only the top keys were illuminated anymore.

So I opened it up and lo and behold... there is no bulb that I could locate. Where does the light come from? It's a mystery. To top it off, the floppy soft-rubber piece that comprises the keys must have shifted or something, because now the pattern of light vs dark keys is all over the place.

What key words can I use to search and read up on this lighting? Thanks.

Reply to
Herb
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Just play with it, there are Light emitting diodes that are used for illmination, they are about the size of the head of a pin for most of these applications. If you want to play fine, if you need a remote, its time to go to your nearest all-0purpose store and buy one for under $10.00 USA.

H. R. (Bob) Hofmann

Reply to
hrhofmann

Herb wrote in news:frjf33hcnkf9aep6c6jsr273pkeqeb2ghf@

4ax.com:

Its just LEDs. Small ones. Likey a resistor or a broken trace is the culprit.

Reply to
Gary Tait

well no, as I'd said, this is different. I experimented and see that it is some unusual device. There is a plastic film with wide, donut shaped white traces that light up. The white center dot makes the connection when a key is pressed, but the rings light up.

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The links between rings don't seem to be broken. Maybe this material just wears out. Or, it's maybe a problem with contact. I tried it with the cover removed and see that the spots that light up are scattered.

Reply to
Herb

Herb wrote in news:pobn33tibkdto1hr22v3fkjnjrtr9ar9lf@

4ax.com:

It could be EL (Electro luminescent) material. Is there a small transformer on the board?

The EL trace could be broken, which you may be able to repair with metallic ink.

Reply to
Gary Tait

Like the watches?

Reply to
Homer J Simpson

Yes, there is a small transformer on the other side of the board.

I noticed today, in a darker environment, that every ring has at least a speck that is lighting. So that new observation tends to go against the idea of a broken trace, I'd think.

Using the term you've provided, I found a journal abstract which describes a type of failure:

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"...defect on the indium tin oxide anode. These spherulites cause the device to delaminate, and this results in a decrease in the luminescence around the defect and, finally, the failure of the electroluminescent device."

Degradation of Organic Electroluminescent Devices. Evidence for the Occurrence of Spherulitic Crystallization in the Hole Transport Layer

Sounds unrepairable, I'd guess.

And yes, I suppose it is just like the stuff on the watch I'm wearing

- though much brighter and lots more area of it.

They should make computer screens out of this stuff :)

Reply to
Herb

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