Size at aperature & Disvergence (mRad)

Hi all,
When looking for a decent RGB projector am I right in saying that size at aperture should roughly be the same for each RGB diodes ?
With your mRad the small the better..

In my case I'm looking at RGB from Goldenstar with the below specs on the diodes..

PGL-V-H-650 1W stability<10%, analog 10k, PSU-V-OEM Unit 5x8m <2m
MGL-H-532 500mW* stability<10%, analog 10k,*PSU-H-OEM 3mm <2m
PGL-V-H-447/445 1W* stability<10%, analog 10k, PSU-H-FDA ~5 ~2x4

I've also been told I would not be able to use the DT40 Wides as the mirrors are not big enough.

Cheers

ideally, all beams should have the same beam diameter at apperture as well as the same divergence
this way, it begins progapagating fully overlapped and it stays the same over distance

the MGL-H green is no problem, you can expand the beam by 1,7 to 5mm @ 1,2mrad easily and this is a fairly nice figure
you could also do with some correction on the blue one (a pair of prisms) and have specs close to the green

that red is going to be a problem though... i strongly suggest you swap it with something else. ask winni for the brighter red options. they also have better beamspecs

this way you will be able to use the dt40w

If you want a good red send me a PM. I can do a red/637 that matches your green and blue. I can match all colors so you have 0.65 mrd full angle ;)

Quote:

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Originally Posted by edison

I can match all colors so you have 0.65 mrd full angle ;)

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how can you make the cni mgl-h have a 0.65 mrad divergence AND fit on the dt40w mirrors?

Because i do some modifications to it. Not selling the greens because people prefer to buy them directly because its cheaper. Not many people want to spend twice the amount for a lower divergence. I spend hours and parts on the module that needs to buy payed. ;) That,s why they are more expencive and since i build modules and projectors full time i need to charge the hours;)

So what will be the beam diameter of the green cni with 0,65mrad?

Beamsize is 3.5 mm at aperture and the spotsize is 20mm at 26 meter. According to pseudoniems beam calculator its 0.63461529942 mrd.

@ LaNeK779 Thanks for the info...Would I be correct in saying by using the prisms or and any corrective optics would reduce the laser output.. ?

Quote:

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Originally Posted by acarusi

@ LaNeK779 Thanks for the info...Would I be correct in saying by using the prisms or and any corrective optics would reduce the laser output.. ?

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sure, you can expect a power drop, but all corrective optics should have an antireflection coating on them that limits losses to 5%, often less than that

if you go with branded optics from edmunds or thor for the pcx and pcv lenses needed to expand the green beam, the losses are negligible

a pair of prisms, if set at an "extreme" magnification could lose even 10-15% of the beam (two prisms, two reflective surfaces, an "aggresive" angle of incidence...). A cylinder lens pair would yield better resutls on the blue correction.


@edison: interesting stuff the greenie beam correction. care to share some more details? i.e. do you change the output coupler lens and then modify the telescope at the beam exit?

I have plenty of prism sets. You can also buy them from dave or from Rob stanwax. Dave is in australia too so that would be the best way to go. I,m not really selling parts but i,m happy to help.

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Quote:

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Originally Posted by edison

Beamsize is 3.5 mm at aperture and the spotsize is 20mm at 26 meter. According to pseudoniems beam calculator its 0.63461529942 mrd.

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So how do you fit this on the widemoves with 3mm apperture?

Just checked and its only 2.9mm so its fits.:) did some more accurate measuring this time;)

Edison,
You have my attention. You have modified a CNI DPSS to produce a 20mm spot @26M with a 2.9mm exit beam!? This can not be through a simple external telescope. What is the stock divergence of the OEM laser that you are modifying? I fully understand if you want to keep the details of such an achievement secret, but can you generally describe your approach? Can you apply this technique to other models such as the Vashio or the DHOM?

As you might have seen that allot of people stept on my toes in the past 2 years and so i,m not to keen on helping people since i,m quite disappointed in how people look at me.

Here,s a list of all the aquisations that are made in the last 2 years:

Not contributing to the forum ( this is solved now but not happy with the asault )
developed a stacking KIT that will save you half of the money when buying a RED module (i could have improved it but i decided after the comments its better to stop selling them. )
Donated a Kit to Selem ( not even a thank you after donating 250 euro worth of parts )
Traded a kit that had problems ( won,t go into details) and traded it back for a full build 6 combiner at no costs (not even a thank you)

Should i go on?

I fully understand that you would think what do i have to do with that. And your right its has nothing to do with you but its just how is feel lately. Sorry but this one i will keep for my self. But i will do some explaining about divergence. If you have a small beam of lets say 2mm at exit and on farfield you have 19mm you have a divergence of 0.65mrd. But when having 4 mm at aperture and on farfield you have 21mm you have 0.65mrd also. So divergence doesn,t say everything about a quallity of a laser. Also stabillity in allignment , temperture stability and other facts like electronics determines the quallity. If you buy a green of me in then it will have also have a better driver and such to make it top quality. I,m not doing some advertising here just i,m picky when it comes to quallity. I want the best and not settle for less.:)

Johan, most of us on this forum know how divergence works, and i think you underestimate the knowledge of allot of people om this forum.

What we would like to know is how you make a mgl-h with a 3mm beam and 1,2mrad into a 2,9mm and 0,65. Because with these numbers you need to have magical collimators or telescopes.

I think you are making divergence assumtions on wrong facts.

Can you confirm you measure the beam diameter at which the beam irradiance (intensity) has fallen to 1/e2 (13.5%) of its peak, or axial, value.

If you cannot confirm this please be more carefull with stating divergence numbers you cant proof.

Of you did proper measurement on the beam profile than I have said nothing.

Wow,
This is a little sad. I assume (maybe wrongly) that you got into this business because you enjoyed the science or the techniques or even the artistic content associated with entertainment lasers and projectors. Now, it seems that to pursue this with enough dedication to earn a living you have become bitter. A thought.... In all seriousness revisit those two years and look rather at your victories. Add up the thank you's, "good idea's" and shows/festivals that you made or are making possible.

I understand about divergence and quality and about the sharing of information on a forum that is primarily about enlightenment and less focused on marketing. However, while your modules are nice, the approach. is transparent; well engineered hardware, good sub-components and careful assembly.There are a number of us around the world that can and do this as well. But, your modification of the DPSS is mysterious to me and in my opinion more valuable to a wider market than even your modules and that's why I asked. Can you apply this to other DPSS lasers? Can you, without revealing any hard won secrets, provide enough of an overview that this level of performance makes sense?

Well i spend 2.5 years on digging out every thread there is about combining, stacking collimating and what not. It just grabs me and i,m picky when it comes to divergence and how things look. I,m not that picky when it goes about 0.5mm because on the outside of any collimated and combined beam there is hardly no power. That,s a hand on experiance and not being theoretically approached or calcultated. What matters is what the customer gets on the outside of a module or projector.If you have a perfect beam and you loose lets say 200mw and your current matches with the Datasheet then you be allright. I burned a hole in the trim of a door on 26 meter with 1 watt because of the tight divergence. The beam on the exit fits the 5mm mirrors so i,m happy with that.:)

Chroma calculates exactly what is needed to have perfect white but in real live its quite different. So who cares if its 0.5mm smaller or bigger as long if its not 1mm or 2mm then its alright:) But as usual i have a different opinion about this. Must be my character :p

Well bitter is not exactly the right word, more disapointed in how people are threating eachother. With all the good intentions you have in any kind of bussiness and supporting hobbyists to climb up the ladder of doing lasershow professionally so they can afford your products in a later stage only 1 or 2 bought a module from me or a projector. The rest wanted to know how to do it so they can save money and build it themselves. They say i want to do laserhows just like the bigger companies but i dont have allot of money. When i help them they never coming back and buy a complete module because they know the trick. They rather save money and buy a bigger car.;) People and this is my live experiance only care how to save money as much as they can. The funny thing is that 80% of people say just before they die i should have been more kind to people or helpful. In my opinion it should work both ways. First i help a hobbyist to climb up to ladder and then he can charge for doing shows and buy a complete module or projector in a later stage. But frankly i don,t believe this will happen in the future but saving money is more important. However the group that is buying my modules and projectors is getting bigger so i,m happy with. Just displaying the facts here. Posting how i feel has probably to do with the mood i,m in lately triggered by the aquisations that has been adressed.;)

Making a 3mm 1,2 mrad laser into a 2,9mm 0,65mrad is just against the laws of physics. Reading the forum for 2,5 year wont change this.

So or you must know magic, or the numbers are incorrect.

Mccarrot your right. With THOSE figures its imposssible. Can,t argue with the law of Physics. But the important question beyond the size of the green is that he wants to buy a projector and so giving him advice is better then arguing about a technicallity. There are several ways of giving him a good start for doing lasershows. I think its better to concentrate on that instead of trying to gain knowledge how you can make your own stuff better.

The 2.5 years might not chance this but it it gave me a good insight how it works arround here that,s for sure. Everyone wants to gain knowledge to get his stuff improved or replaced by spending as little as you can. Mr Acarusi wanted some help but this turns more into a i know it better then you kind of topic. So Mccarrot i think its time to give the boy some real advice don,t you think? :rolleyes:

Like to see what you come up with in terms of support for the young guy :rolleyes:

Well this thread getting a little intense :)... Thanks for the info guys..