5 ns is the pulse width. If you only got one pulse per second which is normal for a home constructed nitrogen laser you won't have much average energy. By using a neon sign transformer you can get a between 50 and a 120 pulses per second. This is getting fast enough to do some work but as you know, a nitrogen laser outputs at 337.1 nano meters which is Ultra Violet.
Ok so it is possible to make one quite cheaply, it can possibly run fast enough to be above the flicker rate but UV light is not useful. You need white light.
Can you turn UV into white light.........Yes.
Can you do it within the 5ns pulse width......Dont know.
Most organic dyes.
Ok so it is possible to make one quite cheaply, it can possibly run fast enough to be above the flicker rate but UV light is not useful. You need white light.
Can you turn UV into white light.........Yes.
Can you do it within the 5ns pulse width......Dont know.
Most organic dyes.
Safety
This sounds realy cool,
there is on thing that has got me wondering,
a friend of mine made a laser for a bet,
the only way they could tell if the laser was
working was by a dark circular patch on the
wall from the laser (wall WAS white).
To the point. Am I going to need protective goggles to watch
my "laser projector", what if one of my kids stands in front an
looks direcly at it, are we going to get retana damage??
Even on my power saw that has a laser on it to show where the
blade will cut it has a warning on it not to look into the laser.
Steve
This sounds realy cool,
there is on thing that has got me wondering,
a friend of mine made a laser for a bet,
the only way they could tell if the laser was
working was by a dark circular patch on the
wall from the laser (wall WAS white).
To the point. Am I going to need protective goggles to watch
my "laser projector", what if one of my kids stands in front an
looks direcly at it, are we going to get retana damage??
Even on my power saw that has a laser on it to show where the
blade will cut it has a warning on it not to look into the laser.
Steve
Questions on my qualifications
To Remp,
When I post, I give careful though to the technical merits of what I am proposing. In terms of my qualifications.... let's see:
1) I have worked on [designed] commercial projectors.... have you?
2) I have in my possession 5 watt Lumileds, the brightest LEDS commercially available and have actively played with them. Have you?
3) I have built custom backlights for LEDs using CCFL tubes.
4) If you read any of my other posts, I have steered people away from LEDS as they are not commercially viable at this point. In fact my post specifically said you would be better off with CCFL.
5) I built a laser as part of a Science Fair project when I was 16.
6) I own several soldering irons, my personal favourite is my Ersyn.
7) There are smart people that have built LED based projectors. You will not see these on the market for a while as they are not commercially viable. They do not use individual LEDS, but LED die mounted on a custom substrate in order to achieve a high flux in a small area to make collimating easier. You can check some of my other posts for discussions of how this is done and some of the issues (heat being a big one). You should also be able to find stuff in Siggraph proceedings.
So back to the technical issues of the homemade laser. 200 KW for 5nsec only yields 1mW average power or about the same as a laser pointer. You would need about 10,000 times this amount of power. The other problem with home made lasers is the life time which in general is very low.
You do not need a DLP to do a scanning based laser system. You can do it with high speed scanning mirrors and you may be able to find them surplus with the controllers. You will need a laser that you can modulate and you will need to do it with three colors and then converge them. Doable, but not easy.
To Remp,
When I post, I give careful though to the technical merits of what I am proposing. In terms of my qualifications.... let's see:
1) I have worked on [designed] commercial projectors.... have you?
2) I have in my possession 5 watt Lumileds, the brightest LEDS commercially available and have actively played with them. Have you?
3) I have built custom backlights for LEDs using CCFL tubes.
4) If you read any of my other posts, I have steered people away from LEDS as they are not commercially viable at this point. In fact my post specifically said you would be better off with CCFL.
5) I built a laser as part of a Science Fair project when I was 16.
6) I own several soldering irons, my personal favourite is my Ersyn.
7) There are smart people that have built LED based projectors. You will not see these on the market for a while as they are not commercially viable. They do not use individual LEDS, but LED die mounted on a custom substrate in order to achieve a high flux in a small area to make collimating easier. You can check some of my other posts for discussions of how this is done and some of the issues (heat being a big one). You should also be able to find stuff in Siggraph proceedings.
So back to the technical issues of the homemade laser. 200 KW for 5nsec only yields 1mW average power or about the same as a laser pointer. You would need about 10,000 times this amount of power. The other problem with home made lasers is the life time which in general is very low.
You do not need a DLP to do a scanning based laser system. You can do it with high speed scanning mirrors and you may be able to find them surplus with the controllers. You will need a laser that you can modulate and you will need to do it with three colors and then converge them. Doable, but not easy.
Don't mean to bang on !!
Here is a replay from the author of the DIY laser site
http://technology.niagarac.on.ca/people/mcsele/lasers/
Are the designs that are being considered going to cut out the
harmful light?
Steve
Here is a replay from the author of the DIY laser site
http://technology.niagarac.on.ca/people/mcsele/lasers/
Are the designs that are being considered going to cut out the
harmful light?
Steve
Cutting out UV light is as simple as placing plexiglass in the beams path. Anybody considering using an Argon laser is insane. As remp so elegantly stated earlier, I am sure that no one would make anything that would be dangerous.
By the way remp, how do you turn UV into white light? Is it as simple as buying a sort of "UV to White Light Lens"?
By the way remp, how do you turn UV into white light? Is it as simple as buying a sort of "UV to White Light Lens"?
You can turn UV into white light using the proper phospors. This is what happens in a flourescent bulb. The issue with a laser is that the spot intensity is very high and you would likely deteriorate the phosphors unless you scanned the laser over a wider area. You can also change UV into visible using frequency doubling, but the light will still be monochromatic.
Alvaius
Alvaius
Before someone else points it out, make that soldering iron an Edsyn. Had my solder and soldering iron mixed up. I have tried using the Ersyn on its own, but it does not heat up very quickly.
Alvaius
Alvaius
http://www.laseramazers.com/laserdiodes.html
So let's see....
$1300 for a 50 mw blue laser....
$950 for a 50 mw green laser...
$240 for a 50 mw red laser...
$10 for a scanning mirror from American Science and Surplus
You'd need a beam combiner...
How would you pulse the laser on and off? Would it be best to block the beam with a high-response time LCD panel (or would that get a hole burnt through it pretty quickly?)
I really don't know what intensity laser we would want. I know that a 5mw laser is pretty bright if you point it in one spot, but if you're scanning it over a 10'x6' wall to get an image, it's not going to be all *that* bright.
On a more serious note, are frequency doublers easy to get, and are they fairly affordable? I know it's usually just a material that the light passes through, but other than that, I'm not really sure how it all works.
--Clint
So let's see....
$1300 for a 50 mw blue laser....
$950 for a 50 mw green laser...
$240 for a 50 mw red laser...
$10 for a scanning mirror from American Science and Surplus
You'd need a beam combiner...
How would you pulse the laser on and off? Would it be best to block the beam with a high-response time LCD panel (or would that get a hole burnt through it pretty quickly?)
I really don't know what intensity laser we would want. I know that a 5mw laser is pretty bright if you point it in one spot, but if you're scanning it over a 10'x6' wall to get an image, it's not going to be all *that* bright.
On a more serious note, are frequency doublers easy to get, and are they fairly affordable? I know it's usually just a material that the light passes through, but other than that, I'm not really sure how it all works.
--Clint
I think mike's idea of taking a conventional light source and focusing it to be laser like would be the best way to go. This very idea is the main topic of the thread
<a href="http://www.diyaudio.com/forums/showthread.php?s=&threadid=9297&highlight=laser">Step Into The Light</a>. Not exactly to same idea, but the same concept of focusing lights onto an lcd screen through the use of a light guide. I have some interesting ideas of my own for this topic, but they will be posted in the other thread.
I would still like to use laser light to produce a projected image, but I will most likely expirament with it in the way remp did in the <a href="http://www.diyaudio.com/forums/showthread.php?s=&threadid=1149&highlight=laser">Laser Projector</a> thread using a tv signal generator and solid laser light, no lcd.
<a href="http://www.diyaudio.com/forums/showthread.php?s=&threadid=9297&highlight=laser">Step Into The Light</a>. Not exactly to same idea, but the same concept of focusing lights onto an lcd screen through the use of a light guide. I have some interesting ideas of my own for this topic, but they will be posted in the other thread.
I would still like to use laser light to produce a projected image, but I will most likely expirament with it in the way remp did in the <a href="http://www.diyaudio.com/forums/showthread.php?s=&threadid=1149&highlight=laser">Laser Projector</a> thread using a tv signal generator and solid laser light, no lcd.
I don't mean to shoot anyone down here, but speaking as someone with a fair bit of laser experience, I feel I should point a few things out:
1) White light gas lasers would not be suitable for any kind of small indoor projection system. The power requirements are enormous, as is the heat dissipation, since the efficiency is extremely low. Here is an example: a small argon (blue) laser of <250mW requires a power supply somewhere around 20A at 240V. It also requires a very large, powerful, and loud fan to remove the heat. That's 4.8KW, compared to, say, a 400W MH bulb. Not very practical.
2) Pumping a dye laser with a nitrogen laser looks easy, but it's not. And it's certainly not something you could set up in your living room. The average power of a DIY nitrogen laser is very low, and the output of the dye laser is much lower still.
Unless you plan on building a large outdoor projection system, I don't think the use of lasers is very practical. That is, until we have a blue laser diode...
1) White light gas lasers would not be suitable for any kind of small indoor projection system. The power requirements are enormous, as is the heat dissipation, since the efficiency is extremely low. Here is an example: a small argon (blue) laser of <250mW requires a power supply somewhere around 20A at 240V. It also requires a very large, powerful, and loud fan to remove the heat. That's 4.8KW, compared to, say, a 400W MH bulb. Not very practical.
2) Pumping a dye laser with a nitrogen laser looks easy, but it's not. And it's certainly not something you could set up in your living room. The average power of a DIY nitrogen laser is very low, and the output of the dye laser is much lower still.
Unless you plan on building a large outdoor projection system, I don't think the use of lasers is very practical. That is, until we have a blue laser diode...
too little too late
Yes, thank you for going into extreme detail explaining why I posted my previous post. Very helpful indeed.
Yes, thank you for going into extreme detail explaining why I posted my previous post. Very helpful indeed.
One of the main purposes of DIY is so guys can discuss ideas even if not particularly practical, or expensive or needing specialised tools but all sensible discussion advances the general knowledge pool.
If we all just said to a poster you can't do this or it won't work without some reasons nobody learns nothing.
It is good to have an open mind even on things other members know, or suspect will not work or have very little chance of success because who really knows where the good ideas are hidding. This is what its all about. Finding the good ideas by co-operative effort.
Nem0 wanted to scan with a laser. Ok maybe he has found out it may not be practical. But even so I bet he learned a lot. I have always been interested in using lasers for projection. But I dont think I would ever consider using a powerful one. I dont have enough knowledge for one thing and I do think it would be dangerous. And of course the cost. But having said that, If I rule aout a large laser I have not ruled out a lot of smaller ones.
For example if cost factors did not come into it, I could use a bar of smaller lasers. The PAL tv system uses 625 lines for TV. Now If I got 625 lasers on a strip each one could draw a line using a rotating polygon mirror. In fact I could do it with half that number because PAL tv is interlaced. Just need a mirror system to make one laser beam slightly reposition to do the odd and even lines. I would need a frame store and a modulator for each small laser and I would need blue and green laser bars and modulators for each and lenses and the list goes on, but it could be done.
The point is the best lighting we have at the moment is a 400 watt metal halide. Works good. Does the job. But it gets hot and its big. We need something more scientific. Something that still does the job but is small and compact and clever.
Might be LED. Might be CCFL. Might be something we have not thought of yet.
If we all just said to a poster you can't do this or it won't work without some reasons nobody learns nothing.
It is good to have an open mind even on things other members know, or suspect will not work or have very little chance of success because who really knows where the good ideas are hidding. This is what its all about. Finding the good ideas by co-operative effort.
Nem0 wanted to scan with a laser. Ok maybe he has found out it may not be practical. But even so I bet he learned a lot. I have always been interested in using lasers for projection. But I dont think I would ever consider using a powerful one. I dont have enough knowledge for one thing and I do think it would be dangerous. And of course the cost. But having said that, If I rule aout a large laser I have not ruled out a lot of smaller ones.
For example if cost factors did not come into it, I could use a bar of smaller lasers. The PAL tv system uses 625 lines for TV. Now If I got 625 lasers on a strip each one could draw a line using a rotating polygon mirror. In fact I could do it with half that number because PAL tv is interlaced. Just need a mirror system to make one laser beam slightly reposition to do the odd and even lines. I would need a frame store and a modulator for each small laser and I would need blue and green laser bars and modulators for each and lenses and the list goes on, but it could be done.
The point is the best lighting we have at the moment is a 400 watt metal halide. Works good. Does the job. But it gets hot and its big. We need something more scientific. Something that still does the job but is small and compact and clever.
Might be LED. Might be CCFL. Might be something we have not thought of yet.
Nem0 said:
What's the point then? I thought the whole idea of using a laser is just because it's extremely intense light? If we focus a normal beam of light, we're just going to have to "un-focus" it either by scanning it with rotating mirrors or open it back up with lenses... either way it's not going to be any brighter than a normal light source. I think the true potential, as you said, is using the laser as the actual image projector (with the TV electronics)... that whole concept gets me really excited. 🙂
--Clint
HanClinto, my post with figures of 10watts red, 2 green, 1 blue for the lasers is based on actual developed products for about a 6 foot screen with LCD projector type brightness. I think that was from a system IBM developed.
Alvaius
Alvaius
ok
ok this might sound impractical, impossible, stupid, whatever. And most likely off topic, but what about the micro crystal led lights? They are definatly wayyyy brighter than the regular leds. The first one i bought was around 15$ but can be bought dirt cheap on ebay now, here is a link to an example http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33713&item=1876201879 I think they have long life, low heat, and are pretty bright (i know they hurt my eyes if i look in them). Wouldnt a few of these do pretty good, with some lights and reflectors of course. You can flame me if you want.. Even if no one agrees, im going to try it soon.
ok this might sound impractical, impossible, stupid, whatever. And most likely off topic, but what about the micro crystal led lights? They are definatly wayyyy brighter than the regular leds. The first one i bought was around 15$ but can be bought dirt cheap on ebay now, here is a link to an example http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33713&item=1876201879 I think they have long life, low heat, and are pretty bright (i know they hurt my eyes if i look in them). Wouldnt a few of these do pretty good, with some lights and reflectors of course. You can flame me if you want.. Even if no one agrees, im going to try it soon.
alvaius said:
Pheeeeew. That's a biiiiig laser. 🙂 So does the required power effectively remove quality laser projectors from the feasability list? I'm not one to give up on any idea, but if we need that kind of power that's just insane.
--Clint
On giving up on laser based displays:
We just need to give up for a few years, maybe more. By then we will be able to buy off the shelf projectors so cheaply that we probably won't care about building our own and hopefully the bulbs will have longer life, be LED based, or at least cheaper to replace.
Alvaius
We just need to give up for a few years, maybe more. By then we will be able to buy off the shelf projectors so cheaply that we probably won't care about building our own and hopefully the bulbs will have longer life, be LED based, or at least cheaper to replace.
Alvaius
hmmmmm
Computers are cheap to buy. People still build them. Why? Cause its something to do. Just like modding computer cases. Its a project that allows you to use your mind, and your hands to tinker with stuff. That is what the majority of the people here have in common. Am I right? We will have a solution. At this time, I personally believe a good way to go would be to find some way of replicating a basic LOA construction to make it more compact. Not just using light guides, but completely rebuilding the bulb itself. If there is a way to do this more cheaply than buying them, it would be a good path in the right direction.
<a href="http://www.lightsearch.com/resources/lightguides/index.html" target="_blank">Check out this site for useful info on light guides and such</a>
Computers are cheap to buy. People still build them. Why? Cause its something to do. Just like modding computer cases. Its a project that allows you to use your mind, and your hands to tinker with stuff. That is what the majority of the people here have in common. Am I right? We will have a solution. At this time, I personally believe a good way to go would be to find some way of replicating a basic LOA construction to make it more compact. Not just using light guides, but completely rebuilding the bulb itself. If there is a way to do this more cheaply than buying them, it would be a good path in the right direction.
<a href="http://www.lightsearch.com/resources/lightguides/index.html" target="_blank">Check out this site for useful info on light guides and such</a>
What then if a combination of Nemo's original idea (using the laser as a light source) and the later ideas of using 3 lasers in red green and blue to create the image were combined.
Would it be possible to scan an extremely bright image onto a 3 or 4 inch screen using tricoloured lasers, or white through LCD or DLP. then use conventional techniques to project that image onto a Large screen or wall. I'm sure Diode lasers of the correct frequency could do the job without too much difficulty.
The power requirements could be reduced and it would certainly be a lot safer to look into is this a feasible soloution?
Would it be possible to scan an extremely bright image onto a 3 or 4 inch screen using tricoloured lasers, or white through LCD or DLP. then use conventional techniques to project that image onto a Large screen or wall. I'm sure Diode lasers of the correct frequency could do the job without too much difficulty.
The power requirements could be reduced and it would certainly be a lot safer to look into is this a feasible soloution?
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