In article
,
Paul Conners wrote:

Would like to find white SMD LEDs suitable for use as backlight for LCD
monitors where the CCFL lamps have burned out. So need is for consistency
between units and... well, "whiteness". ;-)

I really have no help for the question asked, but I think people
interested in the subject may have an answer to one of my questions.

I have a relatively new Samsung LCD monitor using LED back lighting.
When the computer is not providing a signal, such as waking from sleep,
I see a speckling or snow rather than steady background light. I have
two competing explanations.

1. The LED light is sufficiently spatially coherent to generate "laser
speckle." For example, you can see colored speckle in your fingernail
when illuminated by the sun. At one time I saw laser speckle from a
noble gas laser providing a mixture of lines that gave white looking
light.

2. With no signal, the noise in the video line was amplified in the
monitor circuitry. The display was presenting this as a fine churning
snow. When the computer finally was sending a signal, the pixels were
either fully on or fully off.

Does anyone have bette insight on this matter than I do?

--

Sam

Conservatives are against Darwinism but for natural selection.
Liberals are for Darwinism but totally against any selection.