# Replacing diode in laser

and I got a question about lasers. I am owning a LDS 40mw green 100mw red, and I wanted to replace the 40mw diode for a 100mw green diode. Does this requires any power supply increase? Basically a 40 to 100 mw upgrade.

Diod specification

Wavelength:532nm
Power output:100mW with 5% tolerance
Threshold current::260mA
Maximum current:360mA
Requirements Voltage:1.7~2.2V
Working Temperature:+10dgC-+40dgC
Storage Temperature:+10dgC-+50dgC
Lifepan (under normal operation)>7000hours
Size:12mmx35mm


• Can the supply you have produce 360 mA? What kind of output beam does it produce? Getting a new laser optically aligned is likely to be the biggest difficulty. – The Photon Nov 9 '14 at 19:51
• @ThePhoton I got a Ibiza Las 140 rgy - I can't find much details about it :/ – Kavvson Nov 9 '14 at 21:31
• @ThePhoton check documentation lotronic.net/images/lotronic/manuels/… – Kavvson Nov 9 '14 at 21:33

Because the document you linked is for a laser light show device, I'll assume you want to use this for a laser light show.

In that case, you probably do not actually want the green laser to have equal power to the red laser. This is because of the luminosity curve, which shows how efficiently the human eye responds to different wavelengths of light:

(Image source: Wikipedia)

This shows the human eye is near peak efficiency for green light (around 550 nm) and only about 20% efficiency for red light (around 650 nm). So for two laser beams to appear equally bright for human viewers, the red beam should actually have about 5x more power.

That said, if you just want the green beam to be brighter for some reason, you may be able to replace the diode as you suggest. You'd need the be sure the supply is able to provide enough current for the new diode, you'd want the new diode to be in the same size package as the old one, you'd want to be sure to adequately heat-sink the new device when you install it, and you'd want to be sure you can align the output beam of the new diode to the optical projection system correctly. All of these things require knowledge that might only be available in the maintenance manual of the projection system, if they're published at all.

• I see, would it be any easier if I could read/make photo of the inside? – Kavvson Nov 9 '14 at 23:48
• @Kavvson, Questions about repairing purchased devices are off topic for EE.SE. I only answered because I saw there was a good technical reason to not do what you asked about, that would potentially teach future readers something useful about laser displays. We won't, probably, be able to help you with the details of how to repair your particular device/system. – The Photon Nov 9 '14 at 23:52
• Ok, I will ask some friends of mine that know how to deal with such stuff and has proper gear to analyze it ;) – Kavvson Nov 9 '14 at 23:58