Are LCDs Harmful to Children?

As long as they ar not physically broken LCDs are significantly LESS harmful than CRTs. All but the smallest CRTs produce some x-rays (mostly absorbed by the leaded glass), and under certain conditions can store thousands of volts for months after being unplugged (as yours truly discovered the hard way when he was a teen-ager). The 15+kHz sound produced by the yoke magnets may be damaging to the ears - it certainly gave me headaches back when I could hear it. CRTs have flicker that is noticeable by some people ( If you take a photograph of the image on a CRT, Parts of the image will be significantly brighter than others). Due to their size, shape, and weight, CRTs are commonly placed too high, leading to neck strain (especially for those of us that use bifocal glasses of one kind or another - this means mostly older folk rather than young boys).

LCDs produce NO x-rays. The highest voltage in an LCD is around 300V if it uses fluorescent back-lighting, and that at a low enough current to be essentially harmless. LCDs that use LED backlighting have only a few Volts, so no problem there. No Yoke means vastly weaker magnetic fields and no sounds. The longer persistence of the pixels on an LCD, together with the way they are scanned, means no flicker (no problem taking photographs of screens) Due to their size, shape, and weight, LCDs can be put in much more convenient locations (I feel that the correct location is where you would hold a book to read - so laptops are ideal)

Other than the fragility of the LCD, all pluses and no minuses!

"There is an answer in the question itself. You accept that it is harmful."

Not necessarily! he accepted that there is a possibility of it being harmful, and wanted other opinions.

"LEDs, LCDs, Lasers et al deliver light in absolute straight lines"

In a uniform medium, like air at a uniform temperature, light from any source travels in absolute straight lines, and that includes light from fluorescent lights. Of the sources you mention, only the laser emits collimated light (I suspect that is what you meant by "absolute straight lines").

"these rays are powerful..."

The power of the light emitted by any of those sources can vary by several orders of magnitude. Not a fair statement.

"and penetrate some tissues, like a hot knife cutting through butter."

Whether light penetrates tissue, how well it does so, and whether any damage is caused to the tissue depends on the wavelength(s) and intensity of the light. There is nothing inherent in LEDs or LCDs that makes their light more dangerous than light from other sources. The exception would be UV LEDs, but they should never be used in displays.

Bad analogy! A hot knife cuts/melts butter, but unless the knife is exceedingly hot, that melting does not damage the butter in any way. Tissues can be damaged or burnt, but they can't be melted. Any light source powerful enough to cut tissue will definitely damage that tissue.

"Fluorescent or coated luminaries, on the other hand give out diffused light and that is not harmful"

Of the kinds of light sources normally found in homes, the fluorescents emit the most UltraViolet light, and from that standpoint are the most harmful.

The light seen on current LCD screens is emitted by LEDs and diffused by several optical devices, including the Liquid Crystal cells, before it reaches the eye.

The original post was submitted over a decade ago, and there have been tremendous advances in technology since that time.

I'm confident that any harm that may come from the use of LCD screens is NOT due to the light coming from that screen.