Slashdot Mirror
Cold CRT Guns for Thinner CRTs
Fly writes: "According to EETimes, an Austin startup company is close to producing CRTs with cold-emission electron guns. They claim this will reduce the parts needed for electron guns as well as allow for greater control and deflection of the electron beams leading to thinner CRTs. Their technology uses older chip-manufacturing techniquest to deposit diamond tips for the guns on silicon wafers. They hope to enter the CRT market next year."
I have reed an article an year ago about these screens, if they get them to work they should be really cool.
They have almost all advantages of TFTs but have also almost all advantages of CRTs. They are very flat like a TFT, but have no problems with the viewing angle, smearing or bad color display. They need more power than a TFT so they shouldn't be suitable as a replacement of a laptop tft. They also shouldn't have any pixel faults because for every pixel there are many nano electron guns, so if one of these breaks down it doesn't matter. They should be cheaper to produce than a TFT because the process is more fault tolerant.
One of the biggest problems in the development of these things is that there isn't that much room between the electron emiter and the phosphorus, because of that they couldn't speedup the electron to the same speeds they get in a normal CRT and need to find new low-energy phosphoruses.
Jan
With the poor quality of Active Maxtrix (XGA) and LCDs (when I say poor, I mean poor for certain applications) this is nice for us CRT loving folk.
I have a nice Gateway 9500 series laptop with a 15.7" LCD on it. It's great, I will quite often stare at it for hours reading e-books and no fatigue whatsover.
While these LCDs are great for office applications, and text publishing, CRTs will continue to shine for computer gaming, and gfx publishing.
Lighter, smaller, and better looking CRTs are going to be great, now I can realistically tote a 19" monitor to the next LAN party.
A cold electron gun has some other benefits as well. Historically, the biggest problem with making monitor screens truly flat (no warping at the corners) was that the front material needs to be incredibly strong. Screens were rounded slightly to keep them from breaking due to the forces of the vacuum behind them. As screens grew larger and the depth of the monitor increased (in order to let the electron gun get the necessary width) screens had to be stronger. The premium for flat screens is still a couple hundred dollars more than their conventional counterparts.
By having a cold electron gun that allows wider dispersion angles, you can reduce the depth of the monitor, and thereby reduce the strength required from the front screen material.
LCDs will replace CRTs when they are *cheaper to buy*.
--Eric
I really shouldn't have used someone else's email address for this account.
Patent application in 1974, thus no reseach until the patent has expired.
Aren't patents supposed to promote research?
>They also contain lead, which is banned from landfills
;)
Not everywhere. I threw out some old TVs at the local landfill just a short while ago.
I guess the environmentalists gave up when a scientist explained to them how difficult it is for lead to leach out of glass...
If this were actually dangerous you'd see "Tell your kids: don't lick the TV screen" warnings near the tube of the monitor.
>CRT monitors no matter how small are still big, clunky, and waist energy.
Agreed.
> LCD and TFT monitors will take over the market simply because they are better for the sellers as for the buyers, Smaller size cheaper to store, cheaper to ship. IMHO this company has a few merits but is beating a dead horse.
You forget the merits of a CRT:
- Better saturation
- Closer colour tolerance
- Adjustable colour temperature
- Clearer picture
- Better resolution flexibility
- Better contrast
- Better brightness
- Faster response time
- Simple manufacturing
- Consistent quality - No "dead pixels"
- Very high refresh rates making them perfect for 3d shutter glasses
- Cheaper to fix
- No backlight to wear out (no, don't point out the irony)
- No ghosting
- Free antialiasing
All at a much, much lower price than LCDs.
I don't agree they are better for all buyers, just those forced to buy a 2' x 3' desk for their computer.
As far as better for the sellers, other than the weight difference, I don't see how. Normally customers want cheaper and better. Weight and size are often only a concern when the buyer has made a poor choice in purchasing a desk.
If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC
I've not seen this mentioned here yet, but from my reading of the article they are intending to use this on televisions, too.
Yes, I can see the benefits of a shorter tube on a computer monitor (I'm using a 21" monitor right now that is nearly 20 inches deep and weighs nearly 65 pounds). The shorter tube would require less (heavy) glass and less plastic framing. So, smaller and lighter would be good. Also, instant on without requiring a warming circuit is a great plus, too.
BUT, these same benefits ALSO APPLY to conventional TVs, too! My current 27 inch TV sticks well out from my wall unit and weighs so much and is so bulky, I'm not ever going to try and move it again without help. It would be nice to be able to get a larger TV that would fit into the same space, weigh less, and would also not consume power just to keep the electron gun warm for "instant-on".
Other applications: shorter CRT tubes would be an advantage in any technical instruments that have a built-in display. Think: oscilliscope, medical instruments (pulse, BP, oxygen, etc. monitors), in-dash car displays, airplane cockpit displays, etc.
Now, to drool a bit for a more personal application... combine Cold CRT Gun with HDTV!
Presumably the lower initial velocity of an electron stripped from this diamond tipped cathode allows for greater x-y displacement (rastering) in a shorter z displacement (length of tube).
Heated cathodes were originally devised to overcome the problem of the enormous field strength required to strip electrons from a cold, metal cathode. Once enough voltage was generated, electrons were stripped with enormous velocity, and passed through a much longer tube to produce x-rays. Generating visible light with these devices was difficult, and ultimately, dangerous to the viewer!
One problem with the cold cathode technology mentioned in this article would be ensuring that the electron striking the phosphor particles had sufficient velocity to cause an electron shell jump (ie. not enough energy and the phosphor won't emit photons.) By using these diamond tipped cathodes, they must be able to get the electrons off the cathode at lower field strength. Lower field strength = lower velocity, which would allow for a shorter deflection path and a shorter tube. But it won't gurantee that the phosphor will light up.