"Ian Field" wrote in message
...


"Arfa Daily" wrote in message
...


"Phil Allison" wrote in message
...

"William Sommer****** is a ****ing Ass"

Is a DVD laser orange/amber?

It's (supposedly) red. But there would be nothing wrong
using a shorter wavelength.

Utter bull****.

Wavelength is critical to reading the data from a pressed disk.

A short wavelength is needed to resolve fine detail.


** ROTFL !!

What a ****ing MORON and NUT CASE.

FYI

the pit depth on pressed disks is half a wavelength in each case.

DVD players have both IR and red lasers.



.... Phil

Indeed, Phil. And as I said in my reply to William, Blu Ray players have
a blue one as well ...

Since I almost never find CD/DVD lasers with any kind of part number, I
pretty much skated over the few assorted datasheets I'd found.

I sort of only half-noticed that some of them are dual lasers.

There is an obvious danger - I could be mucking about with a DVD laser
trying to get some light out of it, unaware that the IR section is happily
lasing away!


All DVD lasers are dual, even though they have a single lens. The actual
laser diode 'pellet' fixed into the optical block, has both visible red and
infra red devices contained within, and firing out of the same window into
the optical block. The power output of these lasers is generally accepted as
being 'eye safe', although I would still not recommend staring into the lens
on the optical axis. The general advice is to look at the lens from an
oblique angle, and this is considered to be 100% safe. As to seeing whether
the CD laser is burning, they tend to generate enough visible red light to
see, if you shade the lens with your hand. It's clearly visible even in a
brightly lit workshop. The DVD laser burns brightly enough to be able to see
the spot perfectly clearly through the disc.

Arfa