What are lamps for on flat screen tv's?

Question

someone gave my brother a 52inch flat screen hd tv. but they said it needed a new lamp. he hooked up his dvd/xbox and both worked fine so I was curious, what exactly is the lamp for?

Answer 1

LCD TV's have several fluorescent bulbs which for the "back-light" These bulbs create light which shines through the microscopic "Liquid Crystal" shutter array. The shutter array kind of work like an electronic louver shade. This shutter array allows light to pass though a "Color Filter" which creates the Red Green and Blue sub-pixel light which you see. There are about 6 million of these sub-pixel elements in a Full High Definition LCD TV.

I would expect that if you look closely, you will find there is a portion of the screen which looks darker than it should. When the screen is set to all White, this would be the most noticeable.

It is possible to replace LCD bulbs, but it is quite expensive. If you can deal with the poor image quality, a free 52" LCD TV is a great deal!

Astrobuf

Answer 2

Most LCD and projection TVs have a lamp or several lamps that provide white light. The white light then either passes through a LCD filter that removes the colors that aren't needed or is reflected off of a tiny mirror array that only reflects the light the is needed onto the screen.

If the HDTV is still working fine then the lamp(s) are working fine. He might want to ask the person who gave it to him why they thought it needed a new lamp.

In flat panel LCD TVs there are usually several florescent tubes similar to compact florescent lights. If one of these when bad you would clearly see the effect on the screen.

Projection TVs (except for old CRT based units) usually  have a bulb similar to (but stronger than) an automotive head lamp. These bulbs only last a few thousand hours so it's possible that most of the bulb's life has been used up. These bulbs cost a few hundred dollars and are usually user replaceable.

I suggest he find out he make & model # of the HDTV, there should be a label on lower back of the TV. It will also be in the user manual.

With that information he can find out what kind of bulb it takes and perhaps order one at a lower price than what a repair place would charge him.

Answer 3

They're probably  talking about the lamp in a DLP (digital light processing) TV. These are projection TVs and the lamp eventually has to be replaced at a cost of around $150-$200 (I think).

There are also backlight lamps in LCD TVs, but I think these have very long lifetimes, probably the life of the TV.