Red Wavelength Choice

[flecom]

100% agree with you, but the original post says cheap, or there abouts.

so if someone is interested in cheap why we are recommending very expensive.

we would all like perfect projectors, with perfect colours and perfect scanners but thats not the real world. so why arent we saying this is the perfect module for you but if you are after cheap try this

thing is if you have 2W of green and 3+W of blue theres almost no reason to put in something like 1W of 660... (which would be "cheap", at least compared to the other lasers) its simply not going to suffice...

you want a red that can match those power levels? you got to pay to play, sorry

Speaking for myself...

Having gone through the journey of discovery in all that is red when building my first RGB, 640nm was what everyone here was raving about. The logic was clear, nice tight bright red beams, more luminance than 660nm or 671nm. The cost for the power I required was more than I was willing to spend and I must say I'm still ok with my 635nm "torch" (even though there's a slight pink halo to my beams in that projector)!

I have since enjoyed building my own red from 660nm LOC diodes and observed the benefits of these diodes' beam specs. However, the lack of luminance mW for mW is painfully obvious.

Given this experience it seems more than reasonable to use something in the 635-640nm range (especially as I'd prefer to run my lasers at lower Watts with max luminance for audience scanning reasons).

635nm is a bit orange but not too orange. I'm not sure about 637nm. If I remember reading correctly, the new 637nm diodes can be run at higher currents than the 640nm diodes.

So unless my logic and research is flawed, why wouldn't my next 2W red be based on 637nm diodes and why wouldn't I promote this to others despite not yet having the moolah to actually own one!!!

I do get your point Andy, though I suspect the matter of ownership is just simply a matter of time before more of us get past our current projects and on to the next big red!

theres nothing wrong with 635 besides the giant beams, but its also very expensive... for the price of a higher power 635 you might as well buy a 637/642

[allthatwhichis]

Andy, yer just going to have to infrindge on a patent or two and start mass building that 24 banger.

[andy_con]

Thanks for all your inputs, I've got my answer - I didnt say it 'had' to be cheap, was more interested in the results from mixing wavelengths & getting my head around the fact that 1.6W of 637 will be much more visible than multiple W of 660.

I've already got the design & build well underway on this projector so 8 red is the max - I've ordered a couple of the Opnext 637 to start. I will be building the module up with the cheap 660's though while I build & tinker to get it & drivers working etc - much rather kill one of these in testing so I will get a chance to compare.

It's a shame the better diodes do cost ££££, hopefully they will become cheaper in time or get used in some more mass produced consumer gear......

Anybody know of any developments on the horizon?

sorry i took "Cost is a factor so is it worth starting with 660 & upgrading as funds & experience allow or is it pointless?" as meaning cheap, my bad.

637 it is then

[dilbert]

No worries - could have probably phrased it better. I meant cost is obviously a factor but now looking at all the other factors such as visibility, safety, heat, complexity, alignment, cost of extra optics / hardware, size, ability to use my own custom series driver as diodes isolated, match to my other kit I have already etc its no longer such a clear cut issue as I first thought.

Very useful thread for me.

[absolom7691]

For me, even cost-wise... I went 660 for a while and I was constantly dissapointed in the lack of brightness. I now have a 642 and I wish I would not have wasted my money on a 660. So, in essence, it would have been cheaper to go with 642 outright. I would have just had to save for an extra month.