Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers



One laser store meets all your needs

Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Blu-Ray & Violet Lasers







Reply
 
LinkBack Thread Tools Display Modes
Old 12-12-2016, 05:33 PM #17
Class 2 Laser
 
Join Date: Jan 2011
Posts: 360
Rep Power: 1116
lazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond repute
lazeristasUVISIR lazeristasUVISIR is offline
Class 2 Laser
 
Join Date: Jan 2011
Posts: 360
Rep Power: 1116
lazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond reputelazeristasUVISIR has a reputation beyond repute
Default Re: Best lens setup for smallest most perfect focus dot possible at around 300mm dist

Quote:
Originally Posted by AngelG View Post
Now I'm really confused, because what lazeristasUVISIR said about the longer focal length is the opposite of what Cyparagon said:
I'll leave to Cyparagon to explain his thoughts regarding a whole system


__________________
L is for Lasers, and they are good for me.
lazeristasUVISIR is offline   Reply With Quote







LPF List of Laser Pointer Companies (link opens new window)







Old 12-12-2016, 05:52 PM #18
Class 1 Laser
 
Join Date: Nov 2016
Location: Bulgaria,Sofia
Posts: 92
Rep Power: 69
AngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond repute
AngelG AngelG is offline
Class 1 Laser
 
Join Date: Nov 2016
Location: Bulgaria,Sofia
Posts: 92
Rep Power: 69
AngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond repute
Default Re: Best lens setup for smallest most perfect focus dot possible at around 300mm dist

Quote:
Originally Posted by lazeristasUVISIR View Post
I'll leave to Cyparagon to explain his thoughts regarding a whole system
The things are even more fuzzy - the lens systems we're talking about are being sold as "collimating lens" with different front and back focal length. The focus in a spot at given distance is accomplished by changing the distance between the L.Diode and the lens system....
AngelG is offline   Reply With Quote
Old 12-14-2016, 03:23 AM #19
Cyparagon's Avatar
Class 4 Laser
 
Join Date: Sep 2007
Location: Wisconsin
Posts: 9,175
Rep Power: 17961
Cyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond repute
Cyparagon Cyparagon is online now
Class 4 Laser
Cyparagon's Avatar
 
Join Date: Sep 2007
Location: Wisconsin
Posts: 9,175
Rep Power: 17961
Cyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond repute
Default Re: Best lens setup for smallest most perfect focus dot possible at around 300mm dist

Quote:
Originally Posted by AngelG View Post
If shorter focal length makes smaller spot...
Not the focal length of the lens itself, the focal length to the target. Focusing a large beam down in a short distance makes for a smaller spot. If you insist on a 30cm distance to target, you won't get a small spot.

If you're also limiting your lens size to something that fits in a 12mm module, your options are down to just a handfull, all of which will not produce the best spot.
__________________
A problem well stated is a problem half solved.
Cyparagon is online now   Reply With Quote
Old 12-16-2016, 05:03 PM #20
Class 1 Laser
 
Join Date: Nov 2016
Location: Bulgaria,Sofia
Posts: 92
Rep Power: 69
AngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond repute
AngelG AngelG is offline
Class 1 Laser
 
Join Date: Nov 2016
Location: Bulgaria,Sofia
Posts: 92
Rep Power: 69
AngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond repute
Default Re: Best lens setup for smallest most perfect focus dot possible at around 300mm dist

Some 1200dpi LASER printers manage to focus using such small lens.
At a few cm then there are beam shaping cylindric lens (before the mirror) and then after the flat mirror, additional layer of lens which some people call "theta" lens. They're bigger.
I have such lens (beam shaping, theta from printer), but they are acrylic, for 780 nm. Probably the cylindric/beam shaping will help most, but I'm not sure how well this will work at 350 .. 650 mW with 405 nm wavelength. If the distance between the beam-shaping lens is critical, then mine won't work because they're in a monolithic block.

Last edited by AngelG; 12-17-2016 at 11:52 AM.
AngelG is offline   Reply With Quote
Old 01-12-2017, 05:31 AM #21
Exerd's Avatar
Class 2 Laser
 
Join Date: Jan 2010
Location: Utica/Ottawa, IL
Posts: 443
Rep Power: 491
Exerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond repute
Send a message via ICQ to Exerd
Exerd Exerd is offline
Class 2 Laser
Exerd's Avatar
 
Join Date: Jan 2010
Location: Utica/Ottawa, IL
Posts: 443
Rep Power: 491
Exerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond reputeExerd has a reputation beyond repute
Send a message via ICQ to Exerd
Default Re: Best lens setup for smallest most perfect focus dot possible at around 300mm dist

I can help.

Instead of using words like "small", if you simply specify the requirements using a measurement system, we could turn this into physical understanding using the math. That should be straightforward.

I.E. Maximum spot size at target = <0.25mm ⌀

You cannot make an image projection that is more intense or tightly focused than the source image. (While it's easily possible to decrease projected image size by inserting a negative value lens with lens1[-FL]>lens2[+FL], this is merely increasing system FL with same diameter lens, so numerical aperture and efficiency is lowered at that cost.) I use the word 'image' to mean in this case, the laser die. So the intensity at the laser die face always sets the intensity maximum which will never be exceeded at the target. If you take a multi-mode diode, you cannot focus its dot down to a smaller size using optics to compress the energy more than the energy started as. The 405nm single-mode diodes have very high die intensity, so this is of no concern really. It is for your understanding that I added those details, so you can fully appreciate how great a 20X single-mode 405nm could be which is stable at ~1.25W. Maybe next Christmas.

Every lens will have a cross-over point at some distance away where the beam switches from what we call 'finite-conjugate' focus and turns into 'infinite-conjugate' focus (of the projection side that you see as the beam), as you move the lens nearer or further from source laser. That range is a product of focal length over source area. As source area increases, finite-conjugate length decreases. This is seen as you move the same lens from a multi-mode laser over to a single-mode laser. The single-mode has smaller area, and you can see that you can make the beam very narrow a few feet away easily out to maybe 6 feet with G2. The multi-mode cannot reach that far with a G2, its limit is maybe 2 feet before dot is focused to infinity.

I am slightly worried you are designing this system, simply because you should see that a G2 can easily focus to a very fine dot at 300mm with 405nm. I'm kidding, but only slightly.
__________________
Diode Pinouts & Specs
-------------------------
I build lasers.
Exerd is offline   Reply With Quote
Old 01-12-2017, 04:19 PM #22
Class 1 Laser
 
Join Date: Nov 2016
Location: Bulgaria,Sofia
Posts: 92
Rep Power: 69
AngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond repute
AngelG AngelG is offline
Class 1 Laser
 
Join Date: Nov 2016
Location: Bulgaria,Sofia
Posts: 92
Rep Power: 69
AngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond reputeAngelG has a reputation beyond repute
Default Re: Best lens setup for smallest most perfect focus dot possible at around 300mm dist

@Exerd: "So the intensity at the laser die face always sets the intensity maximum which will never be exceeded at the target."
I don't feel it so true. The people use 40W lasers to cut metal. These would destroy themselves if the energy density at the mirror was greater than at the spot...
As for the 1.25 W single-mode 405nm diodes, I don't believe they'd happen, because:
1. It's too difficult;
2. It depends on the demand (and prices) of the Blu Ray devices. There is a reason only 2 companies to be able to produce a 16-x capable drive.
For example I still don't own one (but I have at least 6 x BDR209 SLEDS - LOL).

Last edited by AngelG; 01-12-2017 at 04:22 PM.
AngelG is offline   Reply With Quote
Old 07-30-2017, 06:16 PM #23
Junior Member
 
Join Date: Jun 2012
Posts: 22
Rep Power: 0
Julian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond repute
Julian95 Julian95 is online now
Junior Member
 
Join Date: Jun 2012
Posts: 22
Rep Power: 0
Julian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond reputeJulian95 has a reputation beyond repute
Default Re: Best lens setup for smallest most perfect focus dot possible at around 300mm dist

hello..i can help you with this..first you need to spatially clean the output of the diode, to get an output as gaussian as possible thus eliminating any stray light that generates problems around the focal point. what you need is a "spatial filter" like setup (look it up on google). that is, 2 lenses and a pinhole in the middle(20-200um diameter, if its bigger it wont work perfectly) where the laser focuses. once you are filtered, you can do the galvanometer thing with parallel rays(the output lens of the SF can be set up to do that) and then you need an f-theta lens to focus on the surface, the bigger the numerical aperture of the last lens (that is, the smaller the distance between the last lens and the focal point on your surface) the smaller your focal point will be..and smaller your depth of field will be so it gets harder and harder to focus. it's a compromise.
Julian95 is online now   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 01:31 PM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC