"Lifespan of Compact Disc Laser Diode"

Digital Drive

Upsamplers, DACs, jitter, shakes and analogue withdrawals, this is it.

For certain when a laser diode dies that is it, dead, no going back. But just how long should one expect a CD playerâ€™s laser to last for 3 years, 5 years, 10 years?
There are many high-end CD players of yesteryear circulating the second hand market but if buying a S/H player from 1990 you simply have to go on trust as to how many hours use the player has had. It is the automotive equivalent of buying a used car without knowing how many miles are on the clock.
I have searched for any written information, technical paper of a guide to the lifespan of optical pick-ups but have not been able to find much information.
Here is what I have found so far;
Laser diode life:
----------------
For all intents and purposes, laser diodes in properly designed circuits do
not degrade significantly during use or when powered on or off. However, it
doesn't take much to blow them (see the sections: "How do I use a visible
laser diode?" and "CD player and other low power IR laser diodes"). I have
seen CD players go more than 10,000 hours with no noticeable change in
performance. This doesn't necessarily mean that the laser diode itself isn't
gradually degrading in some way - just that the automatic power control is
still able to compensate fully. However, this is a lower bound on possible
laser diode life span.
Some datasheets list expected lifetimes for laser diodes exceeding 100,000
hours - over 12 years of continuous operation. Of course, I trust these
about as much as the latest disk drive MTBFs of 1 million hours :-).
Laser diodes that fail prematurely were either defective to begin with or,
their driver circuitry was inadequate, or they experience some 'event'
resulting in momentary (greater than a few microseconds) over current.
As noted elsewhere, a weak laser diode is well down on the list of likely
causes for CD player problems.
Of course, in the grand scheme of things, even LEDs gradually lose brightness
with use.
http://www.geocities.com/CapeCanaveral/Lab/3931/laserdio.htm
Having read the above is gives not definite answer. Maybe there isnâ€™t one?
lovekylie

This post is made possible by the generous support of people like you and our sponsors:

Crux Audio

Topic - "Lifespan of Compact Disc Laser Diode" - lovekylie 15:55:42 12/01/06 (3)

Operating life of solid-state electronics. - Al Sekela 14:47:50 12/02/06 (0)

Re: "Lifespan of Compact Disc Laser Diode" - JoKath 17:38:18 12/01/06 (1)

Re: "Lifespan of Compact Disc Laser Diode" - lovekylie 10:29:11 12/02/06 (0)

You can not post to an archived thread.