Laser as light source

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#41
Connor:

Could the power requirements be reduced? I think you would still need a 10 watt red laser, 2 watt green, 1 watt blue (or whatever it was) to get the same light output. Whether you were scanning that light and modulating it with a shutter or crystal, or whether you were scanning it over an LCD panel and letting that do the "modulation" so to speak, there's really no difference in light output. I'm gathering that you would still need a stinking huge laser to get decent image brightness.

--Clint
 
#42
No, because your scanning frequency is reduced, if you only use a small output. And the lower your scanning frequency the less number of firings per second, at the same time youre only looking for the same average power output over the area as say a 400Watt bulb (Infact probably less would do).


for a res of 640x480 pixels, this would give 3091200 firings.
that means each laser would need to output approx
1.29x10^-5Watts or 0.0129mW and with light loss due to feflection and refraction of the 400Watt bulb it could be significantly less than this. OK I know scanning at this speed
would cause its own problems, but they can be fixed, Baird's original TV worked on not too dissimilar principles.

Most Photodiodes can output easily well above this, however the key thing to look for would be fast firing to aid the scanning process.
 
#43
a little off the subject, but....

does anyone know where i can get plans for a ruby laser pistol? i have found them for sale, but really want them for free. If anybody has them, could you post them here for me? i really want to look into this...could be fun....😉
 
#45
Blue Diode Lasers already exist, Sanyo Produce One.
Green is harder to get, although a few green diode lasers exist
most green laser pointers cheat and dont use diodes. Ican't remember what they use but it is something else. It's odd to thinkk that green is the hardest to get given that only 3 years ago they were unable to produce any solid state Blue lights, either for LED or Laser.

As for ruby rod lasers - there was information about them on the link about lasers somewhere above in the thread. you need a cylidrical crystaline structure, a mirror at one end and a smei-mirror at the other. Use a flash bulb to excite the crystal matrix, you have a ruby rod laser at its most basic form.
 
#46
Connor

In my travels I have seen three examples of what you are talking about.

The first was a huge high definition architects drawing board made with a Liguid crytstal underneath in the works that can be drawn on by a low power laser beam but a larger light source provided the big brightness

The second was a device where you draw on the back with a laser beam and shine a powerful light on the front which is reflected back and the laser drawings become much brighter.

And the third was a proposal for use in picture theaters where you draw the pictures on a piece of transparent mica with a laser beam or an electron beam and the main theatre lights shine through the mica and produce your strong theatre pictures.

I dont know if those devices are still used. If you want that info I will dig out some links.
 
#47
I would be interested yes, if it's not too much trouble.
I doubt I'll be building any of these any time soon as compared to elsewhere in europe and apparently the rest of the world; the cost of diode lasers in the uk is prohibitively expensive.
But hopefully the information can be used to find a better way to cheaply build a DIY laser projector.
 
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