[Seany (OP)]

The title asks all []

[JimBob]

I THINK that the fat ones, like the high end Hitachi graphics monitor I am looking at, fires electron at you from the back of the tube. I know that this particular tube uses a defraction grating involved in the process but you need a better answer than this. Let some electronics expert have a goo at this.

Oh - mmmm, I'll leave it, as is There could be some goo in the answer for all I know.
 [)] [xx(]

[Seany (OP)]

Yes.. But why do those flying electrons damage your eyes?

[Batroost]

But why do those flying electrons damage your eyes?

Any charged particle travelling through tissue can cause damage. For example, such a particle can collide with atoms, cause ionisation, and, if it has suffcient energy,  break molecular bonds. Your body has to repair the damage and won't always do this perfectly.

However, I'm not sure that the 'bad for your eyes' arises from this effect.I think it might have more to do with dramatic changes in brightness/light level that our eyes get tired trying to deal with - a bit like driving along a tree-lined road in bright sunshine. The effect of a monitor is less noticeable but the brightness changes are just as pronounced and can go on for hours... An LCD monitor works (partly) by reflected light so - I think - you'd see less pronounced changes in light levels.

Any Opticians on the site?

[another_someone]

My own view is that the problem with is less to do with electron scan, and more to do with the 60Hz-90Hz refresh.  Although this is fast enough that one is not conscious of the screen refresh, but I have nonetheless always felt it does put a strain on the eyes.

The other problem is the imperfect focusing of the electron image on the screen, causing a blurring of the image, and more effort for the eyes to repair the imperfect image.

Ordinary LCD monitors (those used on TV's or computers) does not at all use reflected light at all, and in fact try to limit the amount of reflected light because the interfere with the image (try watching an image on an LCD screen under bright sunlight and you will quickly see how much reflected light gets in the way rather than helping the image).

[lightarrow]

The title asks all []

1. A CRT monitor (Cathode Ray Tube) emits electrons which collides against the screen, generating visible light and some amount of X radiation. An LCD (Liquid Crystals Display) don't have fast speed electrons colliding with matter.
2. A CRT monitor works regenerating the image many times every second, because the electrons excitates pixels on the screen which become bright for a fraction of second. The Refresh Frequency is the number of times a single image is renewed every second. If this is less than ~ 60Hz it will produce an annoying effect yhat could cause hedaches or worse.