X Y laser scanner !

hi there

does anyone know what a X Y laser scanner do really?

i think i saw a link about that used from a loudspeaker but i am not sure what it was doing?

The x-y scanners are used with lasers to generate graphic images. They basically consist of an electromagnetic coil, similar to those found in analog meters. Instead of a meter needle to indicate current, voltage or whatever, a lightweight mirror is attached. This arrangement is usually called a galvanometer or galvo for short. When current is applied, the meter movement rotates the mirror, usually only a few degrees. This will allow the laser beam to be moved ("scanned") from side to side. If the side-to side moving beam is allowed to strike the mirror of another of these devices at 90 degrees, it will allow the beam to move side-to-side (x) or up-and-down (y). High speed galvos are usually quite expensive and require special driver circuitry to make them operate. General Scanning and Cambridge Technology make very high quality galvos for professional use.

Here is a link which better describes the scanners and shows how to make a do-it-yourself loudspeaker-type scanner.
**broken link removed**
JB

well it changes direction of a laser beam using moving mirrors.
one axis (could be galvo or canibalized speaker) makes deflections in X direction. this is than bounced of second mirror. this one is moving in Y direction (perpendicular or 90deg to X axis). result is something that looks like oscilloscope image. the only difference is that it uses laser beam instead of electrons. this means that whole trace is one continuous line. this is not always desirable so laser is modulated (turned on and off).
this way it is possible to make series of lines (straight or curved) and combine them in a picture.
this is really nice job, dont foget to check the movie clips:
http://elm-chan.org/works/vlp/report_e.html

ok thanks for replies

but i can not see what are the uses of this way?

it's usually for entertainment