"Blinking" the LD?

[laserman22]

I read somewhere that "blinking" the LD for PHR, or really any diode is a "bad" thing, and hurts it... What is meant by "blinking", and what are the essential procedures that must be taken in order to maintain the highest "diode life" that you possibly can?


Thank you.

 

[ElektroFreak]

The issue isn't the "blinking" itself, but the circuit that does the blinking. Laser diodes are susceptible to surges and spikes in current, so the "blinking" or modulation circuit must produce a very clean signal. With laser pointers, repeatedly turning the laser on and off can expose the diode to small spikes depending on how clean the driver circuitry is. These spikes may not be enough to kill the diode instantly, but may have a cumulative effect, eventually shortening the life of the diode. Most of the time I'd say that leaving you laser on instead of turning it on every time you want a beam would be ideal, but this is certainly not practical with laser pointers.

 

[Ace82]

There is the pulsed factor, but I haven't heard of anybody making a pulsed driver for diy's... but I don't get out much. ;D

I like IgnorT's expression... The "Duty-cycle Monster"... that seems to have everybody scared to leave their laser on for limited amounts of time only to turn it on again. It is better to leave your laser on for 5 min straight (given a decent heat-sink and reasonable current, but then giving them too much will blow them regardless of duty cycle) then to turn it 1min on and 1 min off 5 times.

 

[john_lawson]

There is the pulsed factor, but I haven't heard of anybody making a pulsed driver for diy's... but I don't get out much.  ;D

I like IgnorT's expression... The "Duty-cycle Monster"... that seems to have everybody scared to leave their laser on for limited amounts of time only to turn it on again.   It is better to leave your laser on for 5 min straight (given a decent heat-sink and reasonable current, but then giving them too much will blow them regardless of duty cycle) then to turn it 1min on and 1 min off 5 times.

lol

 

[pullbangdead]

Eh, it all depends. A laser driven with a 50% duty cycle with 10 nanosecond pulses can be driven to a higher current/power than it ever could be with CW usage. Look at datasheets, pulsed operation is always rated higher than CW operation. But like Elektrofreak said, if your "pulser" isn't good, you can be doing bad things to the diode. But with a good function generator or good circuitry like what is actually used when diodes are reading and/or burning disks, pulsed is better than CW.

 

[NitroxLasers.com]

The type of modulation system you use would really depend on your intent... The diode can be pulsed to increase output power, to extend the duty cycle, or just because you want it to look neat, i.e. for laser light show effects. Google "555 timer IC" and you'll find that there are some pretty neat modulation circuits you can build that are based off this chip.

 

[randomlugia]

I like IgnorT's expression... The "Duty-cycle Monster"... that seems to have everybody scared to leave their laser on for limited amounts of time only to turn it on again.   It is better to leave your laser on for 5 min straight (given a decent heat-sink and reasonable current, but then giving them too much will blow them regardless of duty cycle) then to turn it 1min on and 1 min off 5 times.

I made a thead about this a while ago. I would reccomend building a shutter, then just turn the shutter to keep the laser from coming out, without accually turning the laser off.