Sciencemadness Discussion Board
Not logged in [Login ]
Search the forums Search   Frequently Asked Questions FAQ   View member list Member List   Today's Posts Today's Posts   Forum Stats Stats Back to: sciencemadness.org
Sciencemadness Discussion Board » Engineering and Equipment » Materials and Metallurgy » CRT Phosphor Go To Bottom

Printable Version  
Author: Subject: CRT Phosphor
atomicproject
Harmless
*



Posts: 12
Registered: 4-4-2006
Location: Livermore California
Member Is Offline

Mood: Thermonuclear

[*] posted on 10-8-2008 at 09:45
CRT Phosphor

I am currently working on a homebuilt CRT project. The target screen uses phosphor from a used fluorescent tube. That being the case, the glow is white. Is it feasible to add a very small amount of copper sulfate to the phosphor to make it glow blue? If not what would be good?

Here is a quick youtube link. The CRT is made from a 250 ml vacuum filtration flask and a test tube for the electron gun. The noise in the background noise is from the vacuum pump.

http://www.youtube.com/watch?v=nMOjiZR7R6U

Mark
View user's profile View All Posts By User
Twospoons
International Hazard
*****



Posts: 1324
Registered: 26-7-2004
Location: Middle Earth
Member Is Offline

Mood: A trace of hope...

[*] posted on 10-8-2008 at 16:58


The short answer is 'no'. If you read the wikipedia entry for fluorescent lights you will see why.
The best you could do would be to put a blue filter in front of the crt.
Well done, building a working crt!



Helicopter: "helico" -> spiral, "pter" -> with wings
View user's profile View All Posts By User
12AX7
Post Harlot
*****



Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline

Mood: informative

[*] posted on 10-8-2008 at 17:42


Do you know what pressure that was at? It looks as if you're generating electrons (or positive ions if you're running it backwards!) from a glow discharge.

Blue, huh? Trying for that Tektronix look? ;)

Tim



Seven Transistor Labs LLC http://seventransistorlabs.com/
Electronic Design, from Concept to Layout.
Need engineering assistance? Drop me a message!
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
DJF90
International Hazard
*****



Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline

Mood: No Mood

[*] posted on 11-8-2008 at 03:33


Yea I always thought electrons in a CRT were generated by thermionic emission? So what gives the blue glow :o?
View user's profile View All Posts By User
watson.fawkes
International Hazard
*****



Posts: 2793
Registered: 16-8-2008
Member Is Offline

Mood: No Mood

[*] posted on 17-8-2008 at 09:57


ZnS activated with Ag is the basis for most old blue phosphors. My reference is Handbook of Electron Tube and Vacuum Techniques, by Fred Rosebury. Potassium silicate is the binder. A small amount of barium acetate aids gelation. A full recipe is in the same volume.
View user's profile View All Posts By User
DJF90
International Hazard
*****



Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline

Mood: No Mood

[*] posted on 17-8-2008 at 13:22


I was talking about the electron gun, not the phosphor screen?
View user's profile View All Posts By User
watson.fawkes
International Hazard
*****



Posts: 2793
Registered: 16-8-2008
Member Is Offline

Mood: No Mood

[*] posted on 17-8-2008 at 14:47


Electrons are electrons. Variations in color come from the chemical composition of the phosphor.
View user's profile View All Posts By User
Texium
Administrator
 Thread Moved
19-11-2023 at 12:34

 Sciencemadness Discussion Board » Engineering and Equipment » Materials and Metallurgy » CRT Phosphor   Go To Top