Homemade Scanning Laser Color Projector/TV - Page 3 - Laser Pointer Forums

ElektroFreak · 05-10-2009, 12:42 AM

As far as I know you could use the same types of AOMs that are used in high-end RGB systems. I'm not sure that an LCD would be able to keep up, although it might. Typically, 1-2ms response time is EXTREMELY good for an LCD, so there's no way that 1MHz would be possible. At most, 1-2kHz. AOMs of this type are very expensive currently, but if they were integreated into laser TVs then the price would come down due to higher demand and the lower costs associated with mass production.

Xer0 · 05-10-2009, 10:02 PM

So you say whe must design a working prototype first and throw it on the market before everyone will be able to build it diy with our help? paradox but logical.

Apropos DLP - will it create speckle/interferency when firing a expanded laser beam on it?

ElektroFreak · 05-11-2009, 02:46 AM

The concept of a truly useful DIY laser TV is uncharted waters for the most part. The closest that has been done with good color distribution and decent picture quality is RGB raster imaging using a relatively normal RGB scanner setup, but the resoloution is nowhere near what most people would consider "television". This entire thread so far has been just speculation about the types of technologies and techniques to use in such a project. If you want tp build a DIY laser TV, then judging the practicality of such a project is up to you. What I can tell you is that short of some real ingenuity, the costs outweighs the outcome in most cases. The real ingenuity would come from the mind of whoever decided to undertake the project. If you were to invent some new methods of doing things, the project could suddenly become a much more realistic goal..

Regarding DLPs introducing speckle noise, personally I have no idea. Someone here may know more, but I doubt that many people on this forum have used lasers and DLPs together in their hobbyist projects..

sltvm2007 · 05-11-2009, 09:34 AM

As can be seen from the videos of sltvm2007 in Youtube, high speed modulation of a green laser is possible without an acousto-optical-modulator. However, modulation of a DPSS green laser is not easy because of the very narrow dynamic range of the crystal. Besides some modifications on the optics, LD current should carefully be adjusted in order to protect the DPSS laser.

However, before experimenting on the modulation of LDs, a hobbyist should have a high speed scanner. A relatively slow scanner with a 5-10 Hz slow axis mirror and few kHz fast axis mirror would be good for beginning.

Good luck!

Xer0 · 05-11-2009, 10:16 PM

You are speaking of "modifications on the optics" of the green LD ... what did you to yours?

mechath · 05-13-2009, 10:23 PM

Very cool!

sltvm2007 · 05-20-2009, 07:29 AM

THEORY of OSCILLATIONS

Before beginning to make a scanner we need a little physics.

According to the theory of small oscillations

6.28f= sqroot(k/I)

"f" is the freq of oscillations
"k" is the force constant of the restoring force
"I" is the moment of inertia of the system

Therefore for greater "f" we need greater "k" and smaller "I".

"I" depends on the shape of the mirror and also how it is pivoted.

__________________________________________________ _____
SLTVM: Simple Solutions for High Speed Scanners

"NO MEMS, NO AOM"

VIDEO:
youtube.com/watch?v=NTpwygS8baY

PHOTOS:
photonlexicon.com/forums/album.php?albumid=104

* * * ** * *

* *

ElektroFreak · 05-20-2009, 02:24 PM

^well, duh!

But seriously, while I have a great deal of respect for true DIYers, wouldn't it be simpler to use commercial galvos?

sltvm2007 · 05-20-2009, 04:19 PM

As far as I know, commercial galvos are suitable only for the slow axis (vertical scan).
You need a very fast scanning mirror for the horizontal sweep.
In our project, frequency of the horizontal mirror is 15625 Hz; so tuned to scan the video signal coming from a DVD player.

__________________________________________________ ____
SLTVM: Simple Solutions for High Speed Scanners

"NO MEMS, NO AOM"

VIDEO:
youtube.com/watch?v=NTpwygS8baY

PHOTOS:
photonlexicon.com/forums/album.php?albumid=104

* * * ** * *

* *[/QUOTE]

sltvm2007 · 05-21-2009, 07:51 AM

How can we calculate the moment of inertia of a circular mirror?

Moment of inertia of a circular mirror with respect to an axis passing through its center is given by the formula:

I=mrxr/4

"I" is the moment of inertia of the system
"m"is the mass
"r"is the radius

This means, for smaller "I", "m" and "r" should be made smaller.

__________________________________________________ _____
SLTVM: Simple Solutions for High Speed Scanners

"NO MEMS, NO AOM"

VIDEO:

http://www.youtube.com/watch?v=NTpwygS8baY

PHOTOS:

http://www.photonlexicon.com/forums/...hp?albumid=104

**********

mechath · 05-21-2009, 11:32 AM

What are the dimensions of your mirrors?

sltvm2007 · 05-21-2009, 12:47 PM

radius of the slow mirror is 6mm,
radius of the fast mirror is 1.5mm
___________________________________________
SLTVM: Simple Solutions for High Speed Scanners

"NO MEMS, NO AOM"

VIDEO:

http://www.youtube.com/watch?v=NTpwygS8baY

PHOTOS:

http://www.photonlexicon.com/forums/...hp?albumid=104

**********

mechath · 05-21-2009, 02:39 PM

Thanks,

What are the mirrors made of?

sltvm2007 · 05-21-2009, 07:22 PM

Hard disc material is good for mirrors.

___________________________________________
SLTVM: Simple Solutions for High Speed Scanners

"NO MEMS, NO AOM"

VIDEO:

http://www.youtube.com/watch?v=NTpwygS8baY

PHOTOS:

http://www.photonlexicon.com/forums/...hp?albumid=104

**********

ElektroFreak · 05-21-2009, 07:30 PM

^I always thought that platters would make excellent mirrors, just never actually tried it.

Xer0 · 05-21-2009, 08:07 PM

Yes they are ^^ i have one laying here, it reflects nearly everything!

@slt: i heard about a special "x-ray grade" foil that acts like a dielectric mirror and is extremely thin and light. what about that?

sltvm2007 · 05-21-2009, 11:13 PM

Quote:

Originally Posted by Xer0

@slt: i heard about a special "x-ray grade" foil that acts like a dielectric mirror and is extremely thin and light. what about that?

That's great!!! With such a thin and light mirror one can make an ultra fast scanner. I think more than 1000 lines in each field and 100 fields per second refresh rate will be possible!!!

Where can I get it?

________________________
SLTVM: Simple Solutions for High Speed Scanners

"NO MEMS, NO AOM"

VIDEO:

http://www.youtube.com/watch?v=NTpwygS8baY

PHOTOS:

http://www.photonlexicon.com/forums/...hp?albumid=104

Xer0 · 05-22-2009, 08:09 PM

Erm... i know it was here... just... give a moment

/ suira told me about!
http://laserpointerforums.com/laser_...3&postcount=10

LSRFAQ · 05-22-2009, 11:08 PM

Quote:

Originally Posted by Xer0

So this means you cant just use any AOM and maybe even not a for-multiline one, cause the freuquencies must fit your lasers exactly?

we should get back to the cheaper lcd blanking idea

The only difference is if the AO is AR coated for IR, UV or VIS. Most are coated for vis, and work just fine from 488 to 650. A few really older AOs use a glass that adsorbs green over 500 mW, but most use TeO2 these days.

You do need to have a matched driver, a crystal made for 40 mhz wont work with a 80 mhz driver. AOs are usually +/-7 to 10 mhz wide , so using a 42 mhz driver with a crystal cut for 40 is just fine.

AOs are not frequency specific for laser wavelength, but PCAOMs and AOTFs Are.

Steve

sltvm2007 · 05-23-2009, 08:29 PM

Quote:

Originally Posted by Xer0

@slt: i heard about a special "x-ray grade" foil that acts like a dielectric mirror and is extremely thin and light. what about that?

Thanks. X-ray grade foils might be very thin and therefore flexible I guess. They are useless unless mounted on a suitable support. But this time they will become thick and heavy!

sltvm2007 · 05-28-2009, 01:11 PM

SLTVM: Simple Solutions for High Speed Scanners

"NO MEMS, NO AOM"

VIDEO:

http://www.youtube.com/watch?v=NTpwygS8baY

PHOTOS:

http://www.photonlexicon.com/forums/...hp?albumid=104[/QUOTE]

RASTER!

sltvm2007 · 05-30-2009, 02:02 PM

RASTER: Back-traces deleted

Xer0 · 05-31-2009, 09:00 PM

When will you try to add a Blue? to start, just use a blueray. on a pure white screen it would look like deep 457nm blue. with a bit color adjustment you should get an full color picture!

sltvm2007 · 06-01-2009, 08:52 AM

Quote:

Originally Posted by Xer0

When will you try to add a Blue? to start, just use a blueray. on a pure white screen it would look like deep 457nm blue. with a bit color adjustment you should get an full color picture!

It is possible to add a blueray. Blue lasers are susceptible to direct analog modulation. But combining three lasers by means of two beam splitters makes the optics rather clumsy. I prefer to use a compact RGB laser. However they are not easily accessible yet.

Hallucynogenyc · 06-01-2009, 07:00 PM

looks awesome, but I still don't understand how you managed to make the DPSS green laser to work at such a high frequency

05-10-2009, 12:42 AM	#51
ElektroFreak Class 3B Laser Join Date: Nov 2008 Posts: 3,385 Rep Power: 162	As far as I know you could use the same types of AOMs that are used in high-end RGB systems. I'm not sure that an LCD would be able to keep up, although it might. Typically, 1-2ms response time is EXTREMELY good for an LCD, so there's no way that 1MHz would be possible. At most, 1-2kHz. AOMs of this type are very expensive currently, but if they were integreated into laser TVs then the price would come down due to higher demand and the lower costs associated with mass production. __________________ Laser Resources (for n00bs and veterans alike!) Sam's Laser FAQ (The Laser Bible) http://www.repairfaq.org/sam/laserfaq.htm RP Photonics Encyclopedia of Laser Physics and Technology http://www.rp-photonics.com/encyclopedia.html

05-11-2009, 02:46 AM	#53
ElektroFreak Class 3B Laser Join Date: Nov 2008 Posts: 3,385 Rep Power: 162	The concept of a truly useful DIY laser TV is uncharted waters for the most part. The closest that has been done with good color distribution and decent picture quality is RGB raster imaging using a relatively normal RGB scanner setup, but the resoloution is nowhere near what most people would consider "television". This entire thread so far has been just speculation about the types of technologies and techniques to use in such a project. If you want tp build a DIY laser TV, then judging the practicality of such a project is up to you. What I can tell you is that short of some real ingenuity, the costs outweighs the outcome in most cases. The real ingenuity would come from the mind of whoever decided to undertake the project. If you were to invent some new methods of doing things, the project could suddenly become a much more realistic goal.. Regarding DLPs introducing speckle noise, personally I have no idea. Someone here may know more, but I doubt that many people on this forum have used lasers and DLPs together in their hobbyist projects.. __________________ Laser Resources (for n00bs and veterans alike!) Sam's Laser FAQ (The Laser Bible) http://www.repairfaq.org/sam/laserfaq.htm RP Photonics Encyclopedia of Laser Physics and Technology http://www.rp-photonics.com/encyclopedia.html

05-11-2009, 09:34 AM	#54
sltvm2007 Junior Member Join Date: Apr 2009 Posts: 26 Rep Power: 0	Homemade Scanning Laser Color Projector/TV---Green Laser Modulation As can be seen from the videos of sltvm2007 in Youtube, high speed modulation of a green laser is possible without an acousto-optical-modulator. However, modulation of a DPSS green laser is not easy because of the very narrow dynamic range of the crystal. Besides some modifications on the optics, LD current should carefully be adjusted in order to protect the DPSS laser. However, before experimenting on the modulation of LDs, a hobbyist should have a high speed scanner. A relatively slow scanner with a 5-10 Hz slow axis mirror and few kHz fast axis mirror would be good for beginning. Good luck!

05-13-2009, 10:23 PM	#56
mechath Junior Member Join Date: May 2009 Posts: 3 Rep Power: 0	Very cool Very cool! Last edited by mechath; 06-19-2009 at 01:46 PM.

05-20-2009, 02:24 PM	#58
ElektroFreak Class 3B Laser Join Date: Nov 2008 Posts: 3,385 Rep Power: 162	^well, duh! But seriously, while I have a great deal of respect for true DIYers, wouldn't it be simpler to use commercial galvos? __________________ Laser Resources (for n00bs and veterans alike!) Sam's Laser FAQ (The Laser Bible) http://www.repairfaq.org/sam/laserfaq.htm RP Photonics Encyclopedia of Laser Physics and Technology http://www.rp-photonics.com/encyclopedia.html Last edited by ElektroFreak; 05-20-2009 at 02:26 PM.

05-10-2009, 10:02 PM	#52
Xer0 Class 2 Laser Join Date: Dec 2008 Posts: 310 Rep Power: 6	So you say whe must design a working prototype first and throw it on the market before everyone will be able to build it diy with our help? paradox but logical. Apropos DLP - will it create speckle/interferency when firing a expanded laser beam on it?

05-11-2009, 10:16 PM	#55
Xer0 Class 2 Laser Join Date: Dec 2008 Posts: 310 Rep Power: 6	You are speaking of "modifications on the optics" of the green LD ... what did you to yours?

05-20-2009, 07:29 AM	#57
sltvm2007 Junior Member Join Date: Apr 2009 Posts: 26 Rep Power: 0	THEORY of OSCILLATIONS Before beginning to make a scanner we need a little physics. According to the theory of small oscillations 6.28f= sqroot(k/I) "f" is the freq of oscillations "k" is the force constant of the restoring force "I" is the moment of inertia of the system Therefore for greater "f" we need greater "k" and smaller "I". "I" depends on the shape of the mirror and also how it is pivoted. __________________________________________________ _____ SLTVM: Simple Solutions for High Speed Scanners "NO MEMS, NO AOM" VIDEO: youtube.com/watch?v=NTpwygS8baY PHOTOS: photonlexicon.com/forums/album.php?albumid=104 * * * ** * * * *

05-20-2009, 04:19 PM	#59
sltvm2007 Junior Member Join Date: Apr 2009 Posts: 26 Rep Power: 0	As far as I know, commercial galvos are suitable only for the slow axis (vertical scan). You need a very fast scanning mirror for the horizontal sweep. In our project, frequency of the horizontal mirror is 15625 Hz; so tuned to scan the video signal coming from a DVD player. __________________________________________________ ____ SLTVM: Simple Solutions for High Speed Scanners "NO MEMS, NO AOM" VIDEO: youtube.com/watch?v=NTpwygS8baY PHOTOS: photonlexicon.com/forums/album.php?albumid=104 * * * ** * * * *[/QUOTE]

05-21-2009, 07:51 AM	#60
sltvm2007 Junior Member Join Date: Apr 2009 Posts: 26 Rep Power: 0	How can we calculate the moment of inertia of a circular mirror? Moment of inertia of a circular mirror with respect to an axis passing through its center is given by the formula: I=mrxr/4 "I" is the moment of inertia of the system "m"is the mass "r"is the radius This means, for smaller "I", "m" and "r" should be made smaller. __________________________________________________ _____ SLTVM: Simple Solutions for High Speed Scanners "NO MEMS, NO AOM" VIDEO: http://www.youtube.com/watch?v=NTpwygS8baY PHOTOS: http://www.photonlexicon.com/forums/...hp?albumid=104 **********

05-21-2009, 11:32 AM	#61
mechath Junior Member Join Date: May 2009 Posts: 3 Rep Power: 0	What are the dimensions of your mirrors?

05-21-2009, 12:47 PM	#62
sltvm2007 Junior Member Join Date: Apr 2009 Posts: 26 Rep Power: 0	radius of the slow mirror is 6mm, radius of the fast mirror is 1.5mm ___________________________________________ SLTVM: Simple Solutions for High Speed Scanners "NO MEMS, NO AOM" VIDEO: http://www.youtube.com/watch?v=NTpwygS8baY PHOTOS: http://www.photonlexicon.com/forums/...hp?albumid=104 **********

05-21-2009, 02:39 PM	#63
mechath Junior Member Join Date: May 2009 Posts: 3 Rep Power: 0	Thanks, What are the mirrors made of?

05-21-2009, 07:22 PM	#64
sltvm2007 Junior Member Join Date: Apr 2009 Posts: 26 Rep Power: 0	Hard disc material is good for mirrors. ___________________________________________ SLTVM: Simple Solutions for High Speed Scanners "NO MEMS, NO AOM" VIDEO: http://www.youtube.com/watch?v=NTpwygS8baY PHOTOS: http://www.photonlexicon.com/forums/...hp?albumid=104 ********** Last edited by sltvm2007; 05-21-2009 at 07:24 PM.

05-21-2009, 07:30 PM	#65
ElektroFreak Class 3B Laser Join Date: Nov 2008 Posts: 3,385 Rep Power: 162	^I always thought that platters would make excellent mirrors, just never actually tried it. __________________ Laser Resources (for n00bs and veterans alike!) Sam's Laser FAQ (The Laser Bible) http://www.repairfaq.org/sam/laserfaq.htm RP Photonics Encyclopedia of Laser Physics and Technology http://www.rp-photonics.com/encyclopedia.html

05-21-2009, 08:07 PM	#66
Xer0 Class 2 Laser Join Date: Dec 2008 Posts: 310 Rep Power: 6	Yes they are ^^ i have one laying here, it reflects nearly everything! @slt: i heard about a special "x-ray grade" foil that acts like a dielectric mirror and is extremely thin and light. what about that?

05-22-2009, 08:09 PM	#68
Xer0 Class 2 Laser Join Date: Dec 2008 Posts: 310 Rep Power: 6	Erm... i know it was here... just... give a moment / suira told me about! http://laserpointerforums.com/laser_...3&postcount=10 Last edited by Xer0; 05-22-2009 at 08:11 PM.

05-28-2009, 01:11 PM	#71
sltvm2007 Junior Member Join Date: Apr 2009 Posts: 26 Rep Power: 0	SLTVM: Simple Solutions for High Speed Scanners "NO MEMS, NO AOM" VIDEO: http://www.youtube.com/watch?v=NTpwygS8baY PHOTOS: http://www.photonlexicon.com/forums/...hp?albumid=104[/QUOTE] RASTER! Attached Thumbnails

05-30-2009, 02:02 PM	#72
sltvm2007 Junior Member Join Date: Apr 2009 Posts: 26 Rep Power: 0	RASTER: Back-traces deleted Attached Thumbnails

05-31-2009, 09:00 PM	#73
Xer0 Class 2 Laser Join Date: Dec 2008 Posts: 310 Rep Power: 6	When will you try to add a Blue? to start, just use a blueray. on a pure white screen it would look like deep 457nm blue. with a bit color adjustment you should get an full color picture!

06-01-2009, 07:00 PM	#75
Hallucynogenyc Class 3B Laser Join Date: Jan 2009 Location: Spain, tarragona Posts: 3,156 Rep Power: 163	looks awesome, but I still don't understand how you managed to make the DPSS green laser to work at such a high frequency

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