Where to find crt type phosphors? - Page 1
Forum section: electronics / projects

author: Bendba
author_rank: Regular Contributor
timestamp: January 12, 2018, 01:31:36 pm
content: Hi,I got a pretty simple question here. Where can I buy or find some phosphors (RGB or other colours) to make some custom VFD, CRT indicators (like the ILD3 tube) and eventually electroluminescent displays?The only place I can get some is by scraping the inside of old tv's screens but there is a coat of paint on the inside that makes them pretty dull.ThanksBenNote: I am talking about phosphors, the electroluminescent materials, not phosphorus!

author: Cyberdragon
author_rank: Super Contributor
timestamp: January 12, 2018, 06:15:33 pm
content: There are companies that build custom VFDs.Not sure if something like this will work.http://el-material.com/EL%20Phosphor.htmlThey also have some stuff on Alibaba, however, not all of it is EL phosphor, you'll have to weed through LED phosphor and glow powder.https://www.alibaba.com/showroom/el-phosphor-powder.html

author: Wolfram
author_rank: Frequent Contributor
timestamp: January 12, 2018, 06:48:43 pm
content: Neon Products in the netherlands has a decent selection of fluorescent tube phosphors for sale:http://www.neonproducts.nl/nl/fluorisecentie-poeders.html.

author: LaserSteve
author_rank: Super Contributor
timestamp: January 12, 2018, 11:07:15 pm
content: http://www.phosphor-technology.com/Steve

author: james_s
author_rank: Super Contributor
timestamp: January 13, 2018, 12:14:36 am
content: I was going to suggest Phosphor-Technology but couldn't remember the name. They kindly sent me some free samples a few years ago when I was doing some experimentation. To buy larger quantities of the stuff is surprisingly expensive.

author: Bendba
author_rank: Regular Contributor
timestamp: January 13, 2018, 11:14:03 am
content: Quote from: Cyberdragon on January 12, 2018, 06:15:33 pmI know but where is the fun in there?Thank you all. I guess I'll have to change the way I use Google, I didn't find much.

author: Cyberdragon
author_rank: Super Contributor
timestamp: January 13, 2018, 04:04:01 pm
content: Quote from: Bendba on January 13, 2018, 11:14:03 amThe change you need is to stop using Google. As has been discussed before, Google has gone to garbage when it comes to anything technical or obscure. Try Yahoo, Bing, or Duckduckgo.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 13, 2018, 04:06:30 pm
content: Quote from: Wolfram on January 12, 2018, 06:48:43 pmI don't think these are the same thing - neon phosphors are UV activated, CRT ones are electron activated - I don't know if there's a difference or any overlap in their response - CRT phosphors are pretty specialised, and could be very hard to find in small quantities

author: LaserSteve
author_rank: Super Contributor
timestamp: January 13, 2018, 06:54:42 pm
content: Yen and Weber, Phosphor Handbook, CRC Publishing, is a good read. First Edition, Good.. Second Edition, not so muchBelieve me, as some one who had to purchase X-Ray Sensitive Phosphors for training aids, this is cheap for a known E-Beam sensitive phosphor with modest persistence. Samples I used to buy were 50$ for two grams, so SPI's cost is low compared to commercial sample quantities.https://www.2spi.com/item/04129-ab/Another commercial source:http://www.eljentechnology.com/images/products/data_sheets/EJ-600_.pdfGenerally ninety percent of inorganic UV excited phosphors will respond to e-beam, with an emission wavelength shift. Remember to flash a few hundred nanometers to a few microns of aluminum metal (Thermal evaporator using tungsten coil) over your phosphor screen if it is not directly on metal. Otherwise the screen can charge up and start repelling the low energy electrons..ZnS:Cu:Cl is readily available as "Zinc Sulfide" glow powder, but you may hate the persistence... Your E-beam will "wipe" any persistence already stored, once it reaches the activation energy. Once the e-beam leaves, the persistence will start. So you will definitely see where the beam is landing as a much brighter emission.Going very cheap:http://shop2.chemassociates.com/PAS-zincsulfide.html(I've used this stuff, persistence is medium)Usually high quality screens are made by "settling" the phosphor powder from a water suspension, with a binder and a suspension agent. Gravity does the work for you, but the process is slow.Steve

author: TerraHertz
author_rank: Super Contributor
timestamp: January 14, 2018, 02:14:52 pm
content: Quote from: LaserSteve on January 13, 2018, 06:54:42 pmI guess this is not the same book?PHOSPHOR HANDBOOKYEN WILLIAM H.; SHIONOYA SHIGEOhttps://www.abebooks.com/servlet/BookDetailsPL?bi=22461051875&searchurl=tn%3DPhosphor%2BHandbook%26sortby%3D17&cm_sp=snippet-_-srp1-_-image2I too would like to know more about phosphors.Btw, bendba, I have 200g of Kyokko Phosphor - Type P4 / 271M Color: WhiteIt was an inheritance, I know nothing about how to apply it to a surface, or whether it works.Would you like some?See pic. It was originally in a press-lid tin can that was going rusty. In a plastic bag inside the can, so it's not contaminated.I've been led to believe that many phosphors are extremely poisonous. So handle appropriately.

author: LaserSteve
author_rank: Super Contributor
timestamp: January 15, 2018, 03:07:01 am
content: I work at a university. Shortly after a major terror incident, long ago, we needed a phosphor for an experiment. At the time, sales of certain items was highly restricted (quietly) until further notice and we could not get a short persistence phosphor by any commercial means. Common ZnS:cu was out the question for the prof's experiment. So I requested a text on the production of phosphors by intra-library loan. Knowing that there might come a day when I might need to make a batch, I photocopied some of the materials that looked easy to produce and did not need exotic dopants. Below data is from my notes. This sounds easy, in reality results are only as good as your materials and techniques, but you need a lab furnace to pull it off..Prep of these materials, from what I have read, (and tried!) require very pure starting materials and extremely hot ovens filled with hard to make gas mixtures. For example, the book method of purifying the sulfur goes like this: Ideally you would dissolve the Sulfur in Carbon Disulfide, precipitate it using acetone, and wash that incredibly toxic mess using a filter paper lined funnel, etc... If you really want this to work well, you would start with semiconductor grade chemicals... etc..So here is the method for one that fires at a mere 900'C, uses fairly common stuff, and according to the book, works with short UV, long UV, and e-beam excitation. Broadband green emission centered around 500 nm with no sidebands according to the spectrum.900'C is good, because most of these "easy" materials ls do not start to fuse until 1100'C or higher, which is above the limits you can hit with Nichrome based ovens. Note that you need 900'C final temperature with no more then 20'C overshoot for an hour or more. This one is unique because of its high dopant concentration, making it less of a hit or miss proposition for home brew.As your using Sulfur and a tiny bit of Carbon Monoxide to make this, its an outdoor project, not to be cooked inside unless your at work with a fume hood. This will smell nasty during fabrication. In other words, kids don't try this at home or indoors..Zinc Oxide is used in Sun Screen, is very inert, which is why I selected this methodology for posting here. Most of the other materials you can use are very toxic and hard to get.The raw materials need ball milled in a alcohol slurry or in a mortar and pestle for a very long time. The author suggests ceramic balls for milling to avoid trace metals that may poison the emission.You need a Quartz furnace tube open at one end, one quartz boat for said furnace tube, two quartz test tubes, one that slides into the other. a proper high temperature cork , a thin quartz tube with a closable rubber feed tube, and tank O2... You'll also need finely powdered activated charcoal to make the CO environment.ZnO:S phosphorZinc Oxide 81 GramsSulfur 0.064 gramsAfter mixing, grinding, slurry process, and drying, place the mixture in the very clean small diameter quartz test tube. Slide the small tube into the larger test tube to form a loosely sealed capsule. Push the loaded tube assembly down to the end of the furnace tube with a quartz rod.Fill the quartz boat with a few tens of grams of carbon powder, then place a plug of quartz wool in the cold end of the tube to slow or block gas diffusing into the hot zone as much as possible.Stick the thin quartz tube into the stopper and seal the furnace tube with the stopper. Back fill and flush the furnace tube with Oxygen using the thin tube, to displace Nitrogen, which blocks the reaction.Cap the fill tube with rubber tubing and close it off with a tubing clamp. Make sure there is a tiny hole in the stopper for a little air to diffuse in and to prevent pressure buildup.The O2 flow is OFF once the oven starts to heat up, the idea being that the charcoal dust slowly burns away to create a reducing atmosphere of Carbon Monoxide in the tube... If you leave the O2 on, you will just have a burnt mess or a possible risk of fire due to hot O2 escaping the furnace.Fire for one hour at 900'C ... Cool slowly. Book says if you want to shift emission towards the blue, replace 20% of the ZnO with Magnesium Oxide, but I have not tried that version.UV efficiency is supposed to be ~60%. Persistance is 1 to 10 microseconds....According to the book, you can fire this one, check its uniformity, and if needed, re-fire it in the reducing atmosphere after another grinding.DISCLAIMERS AND WARNINGS:Quality production of the material using these 1940s techniques is a bit of hit or miss. Your mileage may vary.... High temperature ovens and Oxygen are a bit dangerous if you have never worked with them together... Buying raw sulfur will put you on the "radar" of certain government groups. Carbon Disulfide is poisonous and nasty, and dissolves most containers.. Unless I worked in a chemistry lab, I'd skip that step. Never use Carbon Disulfide at home, if you can even get it.Nurdrage has a video on home made phosphors, and so does Ms. Ellsworth...https://www.youtube.com/watch?annotation_id=annotation_732376&feature=iv&src_vid=pmQqdYrn9g8&v=veOiHb-KuSEREF:Zink Oxide and Zinc Cadmium Oxide Phosphors,Journal of the Electrochemistry Society, Lehmann, W, Volume 115, Page 538, (1968)Steve

author: james_s
author_rank: Super Contributor
timestamp: January 16, 2018, 08:32:31 pm
content: Quote from: TerraHertz on January 14, 2018, 02:14:52 pmIt depends on what it is. The original P4 phosphor used in B&W TV CRTs contains cadmium which is quite toxic. I don't think the rare earths used in color tubes or the common green and amber phosphors are particularly hazardous but I certainly would not spread them on toast or inhale them.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 17, 2018, 02:41:06 am
content: You guys are getting into "things I won't work with" territory....http://blogs.sciencemag.org/pipeline/?s=things+I+won%27t+work+with

author: John Heath
author_rank: Frequent Contributor
timestamp: January 17, 2018, 07:33:47 am
content: Cheap sources. Tide powdered soap for whiter than whites. Sprinkle the soap between two sheets of plexi glass and you have a phosphor screen. Also a new white t shirt for a phosphor screen. They have phosphor to look extra white for marketing.

author: ikrase
author_rank: Regular Contributor
timestamp: January 17, 2018, 07:47:29 am
content: QuoteJust to clarify, you've tried this, with electron beams?

author: LaserSteve
author_rank: Super Contributor
timestamp: January 17, 2018, 08:12:17 am
content: Quote from: Alex Eisenhut on January 17, 2018, 02:41:06 amThat's why I described the ZnO phosphor. While varying mixes of Zinc Sulfide and Cadmium Sulfide (Artists Yellow Pigment) can be fused together at low temperatures to create colors from the IR , Red, Orange, Yellows and into the Green, Zinc Oxide is the key inert ingredient in Sunscreen. Very inert to start with.Much safer then oxides and sulfidess of terbium, cadmium, , barium, erbium, galates, selenium, etc that are in the published recipe book of classical phosphors that I have.Most of the safer phosphors are simple carbonates or oxides, but the simple ones have low quantum yields.Fortunately it was quickly realized that the Beryllium based phosphors of the 40s and 50s needed to go on the scrap pile of history.I do feel sorry for the plant workers who died in order to learn that. Which lead to guidelines about what could go into CRTs and Lamps used in the home.The real toxicity issues come from breathing or ingesting modest amounts of the powder or getting a cut from the coated glass. The powder in the lamp or CRT is held by a tough fused inert binder, you really have to work at it to remove phosphors from the glass.Detergent is not for vacuum use, the organic blue dye used will decompose when hit by plasma or e-beam.Steve

author: John Heath
author_rank: Frequent Contributor
timestamp: January 17, 2018, 08:50:04 am
content: Quote from: LaserSteve on January 17, 2018, 08:12:17 amAn electron lighting up tide soap would depend on the energy only. In the case of Mr electron it's energy would be its velocity. For a small black and white TV with a 10 K volt acceleration the velocity is in the neighborhood of 15 percent c. The energy of red green and blue light is 5 volts max per photon so it is a cake walk for even slow electrons to light up tide soap or t shirt phosphor. However in fresh air hitting a t shirt or soap a UV laser would be easier yes / no?. Somewhat like going into a night club and you white shirt lights up in UV black lights.

author: LaserSteve
author_rank: Super Contributor
timestamp: January 17, 2018, 01:19:18 pm
content: The dye 4,4-diamino-2,2 stilbenedisulfonic acid , aka an optical brightening agent, is an organic. Optical brighteners are what cause a t-shirt to glow.It will boil at the temperatures needed to outgas a VFD tube during processing.While I could not find vapor pressure data on it, its safe to assume the level of e-beam needed to make a prolonged life, successful hobbyist VFD will destroy this compound, cause it to outgas, and promptly ruin his work.Oh yeah, it will glow, briefly, then outgas, promptly poison the cathode, and ruin a heck of a lot of work, forming a plasma, and vastly shortening the mean free path for the electrons in his tube. Assuming you could keep it cold when processing the tube.I'm assuming the O.P. wants to make a classic VFD, not some short lived contraption.My eighth grade science fair project was "How do you Make a FlouresentLamp?" . If I had access to Argon way back then, instead of the air/oil vapor mixture from a backwards refrigeration compressor, I might have got to the point where I could have sealed the tube off.Since these days I support an Auger system, and rebuild gas laser tubes once in a while, I've got a good idea of what would happen if he used a detergent in a lamp or vacuum tube.Steve

author: John Heath
author_rank: Frequent Contributor
timestamp: January 18, 2018, 09:47:40 am
content: Quote from: LaserSteve on January 17, 2018, 01:19:18 pmYes out gassing of a white t shirt inside a TV CRT would be a problem , ha. A CRT vacuum is in the neighborhood of 1 torr ^-14 to to ^-17 range. Have to use a mechanical pump followed by a then diffusion pump followed by a getter burn just to get there. On the other hand a UV laser is only 20 bucks for a non vacuum soap or t shirt type display. If you had a UV light source and white t shirt back in grade 8 it would be a fluorescent display yes/no?

author: LaserSteve
author_rank: Super Contributor
timestamp: January 18, 2018, 04:53:39 pm
content: For the next poor soul who asks this question...https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwj1l9a9_OHYAhVDG6wKHfTRAF8QFggpMAA&url=https%3A%2F%2Fwww.researchgate.net%2Ffile.PostFileLoader.html%3Fid%3D53e4101fd685cccb7b8b4653%26assetKey%3DAS%3A273575271960579%401442236835312&usg=AOvVaw1j68APVIpJjbY572k-a9cIDownload link to a copy of "Inorganic Phosphors" , which is quite a rare text, no idea if they have the rights to post...Steve

author: LaserSteve
author_rank: Super Contributor
timestamp: January 18, 2018, 04:56:41 pm
content: My science project had eight phosphors, no teeshirt or laser needed. When you live 45 minutes from Nela Park, when GE still made lightbulbs in the USA, life was much easier. It was easy to find a variety of colors in N.E. Ohio surplus shops that used to be in a ring around Cleveland.. I think the OP has enough data to proceed, at least until he finds he needs pre-welded Dumet leads and non darkening, reduced lead, glass for neon tubes (Must have correct ~88 COE). Steve

author: westfw
author_rank: Super Contributor
timestamp: January 19, 2018, 01:19:20 am
content: There are a wide variety of "glow in the dark" powders available these days, based on strontium aluminate. I have no idea how they'd behave under an electron beam, or whether their persistence would make them unusable in this sort of application, but they're inorganic, said to hold up to being embedded in molten glass, and are cheap enough to experiment with...