Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Laser Pointer Store

Why do most projectors not use direct green?

Joined
Oct 13, 2011
Messages
115
Likes
4
Points
0
From reading this forum five years back there was a lot of posts on how direct green diodes were developed for use in laser video projectors.

I have google and almost every top end laser projector on the market still uses blue diodes along with color changing phosphors to get red and green. What was the purpose of the green diodes if they are not being used in current video projectors?
 

RedCowboy

Well-known member
LPF Site Supporter
Joined
Jul 10, 2015
Messages
6,830
Likes
1,653
Points
113
Efficency!

From Jan 2016

http://www.laserfocusworld.com/arti...ill-help-cure-green-led-efficiency-droop.html

-----

This is from 2013 but you see it's not a new problem, copper backed stressed lattice is supposed to add to toughness but still green lags well behind, that's why street lights, auto lights, house lights, your pc screen backlight, it's all a blue led pumping phosphor because of efficiency, and as well as saving power even a bigger issue is less waste heat to get rid of.

http://www.nature.com/nphoton/journal/v7/n8/full/nphoton.2013.202.html


----------------

As to why, well you crawl before you walk and have to start somewhere, they have uses in picos and stage lighting, lightshows, aiming lasers that need high visibility at low power and the directs do solve some of the dpss problems, in time the green gap may be solved, but right now blue pumping phosphors is taking over lighting everywhere, convince store lighting, even my wal-mart parking lot lights are led.
 
Last edited:
D

Deleted member 16589

Guest
I have often wondered that about the phlatlights They use blue and red phlatlights and blue diodes to produce green. Why no green phlatlight? Luminus Makes them.
 

Cyparagon

Well-known member
Joined
Sep 12, 2007
Messages
9,520
Likes
1,044
Points
113
Seems to me a phosphor disk would be a lot cheaper than a bank of laser diodes and the optics/cooling/drivers to run them all. :can:
 

RedCowboy

Well-known member
LPF Site Supporter
Joined
Jul 10, 2015
Messages
6,830
Likes
1,653
Points
113
Some new projectors such as the Panasonic " Solid Shine " use nothing but blue laser diodes to pump phosphors that make all the RGB, yes even other blue.

There are also all LED units.
 
Joined
Oct 13, 2011
Messages
115
Likes
4
Points
0
Efficency!

From Jan 2016

Cubic gallium nitride will help cure green-LED efficiency droop - Laser Focus World

-----

This is from 2013 but you see it's not a new problem, copper backed stressed lattice is supposed to add to toughness but still green lags well behind, that's why street lights, auto lights, house lights, your pc screen backlight, it's all a blue led pumping phosphor because of efficiency, and as well as saving power even a bigger issue is less waste heat to get rid of.

http://www.nature.com/nphoton/journal/v7/n8/full/nphoton.2013.202.html


----------------

As to why, well you crawl before you walk and have to start somewhere, they have uses in picos and stage lighting, lightshows, aiming lasers that need high visibility at low power and the directs do solve some of the dpss problems, in time the green gap may be solved, but right now blue pumping phosphors is taking over lighting everywhere, convince store lighting, even my wal-mart parking lot lights are led.
Thanks for the info. I guess the green diodes aren't useful until they bring the efficiency up.
 

RedCowboy

Well-known member
LPF Site Supporter
Joined
Jul 10, 2015
Messages
6,830
Likes
1,653
Points
113
Not for projectors, but some super high end or specialty units may use them and tout that they have a better range of colors.

Christie did a big Imax with RGB lasers, not the old one but a 2014 model.

Necsel lasers to power new IMAX projectors <Click


Now here's about the 2012 model.

http://www.display-central.com/subs...christie-laser-projector-shines-at-ibc-in-3d/ <Click

p.s. NECSEL lasers that I have heard about are very temperature sensitive, so if you see one on ebay be aware they may be a headache.
 
Last edited:




Top