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Coating Promises Scratch-Proof CDs, DVDs, LCDs
13.7BillionYears writes "NewScientist reports that TDK has developed a transparent polymer for LCD screens and optical media that is impervious to general neglect and abuse. Quoth the reporter, 'In one of the most convincing technology demonstrations this reporter has witnessed, I was handed a CD, a wire-wool pan scourer and some permanent marker pens, and invited to scratch or mark the discs. Hard as I tried, I could not make a single mark on the disc with the scourer. And the ink simply wiped off.' The coating is apparently responsible for Blu-Ray's new caddy-less form factor."
A harder plastic can make a bit of a difference, but once sand is involved polymers are not hard enough. The other way to do things is to have a surface that is soft enough to just get out of the way when something hard moves out of it - which is the approach taken on liner of chutes that crushed rock slides down.
I also found it interesting that Sony-Ericsson released a similar plastic coating for the screen of their new phones, but isn't saying a word about how it's made or what other applications it has.
A caddy is a protective cover for your disc that stays on the disc even when it's in the drive. A long time ago CDs used to come in caddys (or at least, I remember seeing a CD-ROM drive that used caddys when I was little). It's a stretch, but you could call the plastic parts of a floppy disc a caddy. The main reason you'd want to avoid them is that they add bulk to the disc.
"[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz
I did some research on wear resistent metal coatings and found they scratched and wore off.
(FYI TiAlCN and Boron Carbide worked nicely)
I have trouble believing anyone could be all that scratch resistant, if you want a real test, use a bit of sand or drag it across concrete/brick.
I've found many of my CD's got damaged by only a few small sand particles.
Often, CD rot is due to poor evacuation of oxygen between the layers of the CD during manufacture. If the O2 is already present, a new coating won't help much.
People should not fear what they do not understand; people should fear because they do not understand.
But I'm wary of anything touted as -proof. -proof smacks of marketing getting their grubby paws on it.
e ss_ad_.htm#3.6.1.
Sure they gave you some steel wool to scratch the CD with, it's only a 3-4 on Moh's hardness scale, as in not very. I'll be impressed when it can withstand being tossed shiny side town on a little bit of sand on a hard surface and rubbed around vigrously. Quartz/glass/sand/silicon are a great deal more likely to encounter your CDs than steel wool is and they're a 7 or so on Moh's hardness scale.
I picked Moh's because to explain because: Mohs hardness is defined by how well a substance will resist scratching by another substance. from: http://www.calce.umd.edu/general/Facilities/Hardn
Question everything
camaro
You mean Firebird, or more specifically, a Trans-Am. From what I remember reading, they had 13-some cars just in case they broke one... which did happen.
Did you ever notice that for the "car action" scenes, most of the footage was re-used ("turbo boost" stuff)...
I am somewhat sad at myself for still having a weak spot for a shiny black T/A - especially those model years. My friends call me white trash because of it.
Karnal
Best use I've found for AOL CDs is to put them in the microwave for around 15 seconds. Fun, safe(ish) sparkly light show.
Aaanyway...
If you can't think of something nice to say then don't say anything at all. No, REALLY.
They are lifted, but they spin on the tray when they let go.
I had a drive that Gateway replaced for free because it had a nick in the tray that was scratching all my CDs to the point of some become unreadable.
I'm out of my mind right now, but feel free to leave a message.....
According to TDK's site, they already have DVD-R media with that coating.
Well since DVDs use visible light lasers (650nm) to both write and read, and you since you can see through the plastic to the recording surface, there's no reason it shouldn't work.
http://www.scratchlessdisc.com/
This is a much lower-tech solution, although I could see where it would be very useful.
Apparently the guy who patented this made a few bucks off of the idea, which he supposedly came up with while stoned. Or so says a friend of mine who knew the guy.
You are in a maze of twisty little passages, all alike.
You are making the invalid assumption that the surface of a CD has to actually be highly optically permissive. It doesn't. The laser is out of focus when it passes through the surface of the disc, and in focus when the laser strikes the metal layer of the CD. The greater the distance between the surface and the metal, the more scratch-tolerant the optical media. This coating could be utterly unsuitable for coating, say, eyeglasses, yet be ideal for CD, DVD, et cetera.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Actually, what you're referring to is the side and rear windshield tempered safety-glass, which breaks into small squarish pieces with any sharp impact.
The windshield is actually layers of glass and a clear plastic, which holds the glass together as it shatters.
Safety glass breaks into cubes, but normal glass spiderwebs.
As a volunteer firefighter, and not only being trained on how to remove automotive glass expediently, but also having seen "forehead dents" in windshields (luckily no full-ejection of occupants out the windshield), I can attest to how it actually breaks.
BMW is putting Polycarbonate windows in the 740 series cars. You can't break those with a sledgehammer (I know someone who tried, our instructor on jaws of life tools).
I second your Rain-X findings but I'd like to add some more negatives. It seems to provide a glare at night with or without rain for a few days after applying it. Another negative is once the Rain-X starts to wear off and you need to use the wipers again, they do not work very well. I guess the Rain-X adheres to the blades and probably something that could be cleaned off with some rubbing alcohol. Even with the negatives, I still use Rain-X on all of the cars windows including the side mirrors.
Bad boys rape our young girls but Violet gives willingly.
The problem with Plexiglass is that it scratches very easily. Despite it's use in things like "shark tunnels" in large public aquariums because of its strength, it still requires very delicate care in cleaning. Plexiglass with this stuff as a surface coating would make an excellent combination because it would have the strength without the scratching. It could be used for things like storefront windows, eliminating the need for folding security gates during off-hours. Think of it as a real "transparent aluminum".
Using this for discs is great, but will it solve the problem of degrading recordable media? There is still the problem of dye degradation.
Most CD/DVDs are FAR more vulnerable to damage by being scratched through the top side. The bottom side has most of thickness of the disc (clear, resilient plastic) between the surface and the data medium. The actual information is stored on the backside of the substrate at the TOP of the disk, and even a shallow scratch through that will destroy data.
You can have a pretty massive scratch on the plastic side, and judicious application of nose grease and a high-quality reader will do just fine. Scratch the data layer, and you're screwed.
They can still texture the top side, but *that* is the side that requires the best protection you can get on it, either way.
"We have to go forth and crush every world view that doesn't believe in tolerance and free speech." - David Brin
Not so for DVD's. All dvd's are "sandwiches." This is so that we can have double sided dvd's that aren't thicker than single sided ones.
A typical dvd would look like this:
Plastic coating.
Side 1 Content.
Back to back glue.
Side 2 Content, or just a blank side.
Plastic coating.
(optional) Label (if not a 2 sided DVD)
The total thickness is about the same as a CD tho, so only half as far to get through to the good stuff from either side. But as such both sides have some protection.
WRONG again. DVDs have the data in between two layers of plastic. So scratch the label as much as you want, it won't damage the data as long as you don't puncture the plastic.
;-)
Fun Tip: Nuke a DVD for a minute or two and the two plastic disks will slide apart. Double the frisbees double the fun.
I'm just this guy, you know?
Worth a try if that's your setup.
.02
cLive ;-)
-- Trinity in high heels carrying a whip: The donimatrix - there is no spoonerism
Re: Automotive windows
The whole point of tempered automotive glass is to minimize injury to the heads of the passengers. Windshields use multiple layers of glass with a plastic film in between, to keep broken bits from flying into the vehicle's occupants. Side and rear windows are designed to break into small enough peices that lacerations are minimized, and lack stabilizing layers.
Contrast this with a plastic window. Most plastics are not very sharp when broken. The windows can be designed to bend outward easily. And they don't weigh anywhere near as much as glass, lessening the problems of momentum.
And since plastic doesn't have the inherent problem of normal glass (big, heavy, jugular-slicing chunks of razor-sharp material being flung about at incredible speeds), it doesn't need to have the same safeguards. To state otherwise is an example of FUD.
The safety problem, then, is easy to quantify:
Using your head at a velocity of 60MPH, does it hurt more to hit a 40lb glass windshield which will shatter (but maintain its mass and inertia) on impact, or to hit a 10-pound shatterproof plastic window which is flexibile enough to absorb your forward energy, and will remove itself outward from the vehicle on impact?
I don't have the solution to that problem, but I'd say that it's close.
On with the anecdotes:
Plastics (Lexan, in particular) have been used in race car windows for a Really Long Time Now. And since dead/blinded drivers can't win races, the people involved in selecting said windows have a rather vested interest in making sure that they're safe. So far, they've done just fine.
I'm guessing that if the automobile industry is keen enough on saving weight and materials that they're seriously discussing increasing voltage to reduce the weight of electrical wiring, that they'd really appreciate windows that aren't as heavy as the glass that they've been using forever.
If only Lexan didn't scratch so easily, I'm sure they'd jump all over it.
Oh, wait, I almost forgot. Lexan == polycarbonate == the stuff CDs are made of. Didn't TDK recently develop a coating to solve that problem?
Kid-proof tablet..
There's no mention of UV resistance and degradation, so cars may not be the best application for this product right now.
Mercedes already has a nano-tech ceramic paint that's supposed to be twice as durable in the long haul.
http://www.azom.com/news.asp?newsID=917
(too lazy to use html)
Compare a DVD and a CD of yours and you'll see that the DVD is made of two plastic layers with the reflective surface between them, while the CD only has one with the reflective surface at max barely protected bv a coating.
If you have an old or damaged DVD and CD, try scratching them from the label side. The CD will instantly have scratches that can be seen from both sides, but I'll bet you won't damage the reflective surface of the DVD if you scratch it with anything short of a box cutter. That's why the manufacturer logo and other preprinted text on the DVD-R label side appears a bit "fuzzy" sometimes - it is beneath 0,6mm a polycarbonate layer.
This was the only drawing I found without searching too long. It pictures a dual layer DVD, but the general construction scheme is the same.
Upper polycarbonate layer:
Outer label (optional, mostly used on movie DVDs)
Polycarbonate 0,3mm
Data U-1 and semi-reflective layer upper side (optional for dual-layer, double-side discs, only with no outer label)
Polycarbonate 0,3mm
Data U2 and full reflective layer upper side (optional for double-side discs, only with no outer label)
Inner label (optional, used on most DVD-Rs, only without label and not on double-sided discs of course)
Bonding glue
Lower polycarbonate layer:
Full reflective layer down side and data D-2
Polycarbonate 0,3mm
Semi-reflective layer down side and data D-1 (optional for dual-layer discs)
Polycarbonate 0,3mm
Thickness total ~1,2mm. All DVDs have two layers of polycarbonate with the primary reflective surface sandwiched between them (the secondary, if present, is embedded within). You can scratch the underside, diffracting the laser but you cannot peel off the reflective coating anymore like you could with CD-Rs. That gives DVDs a better durability and theoretical aging resistance, but how fast the glue between the sandwiches dissolves or affects the refletive layer is yet to be determined.
Each reflective surface has a capacity of ~4,7 GB, hence dual-layer discs have ~2x 4,7 and double-sided, dual-layer discs ~4x 4,7. (a little less due to longer pit lengths in dual layer recording) The rare "double-sided DVDs" actually have two sides of data like an old vinyl recording.
I have experience with plastic aircraft windows. Canada's National Research Council has a pneumatic bird gun that can fire 8 lb. birds up to mach 1.5.
.2 goes right through polycarbonate, and it does shatter. Unfortunately for the pilot, the edges of shattered polycarbonate are sharper than razor blades, certainly sharper than the edges of shattered glass. The canopy for the F-5 is about the worst design from this standpoint.
.22 cal go right through 15-year old bulletproof glass. So polycarb gets brittle when exposed to air, hence the sandwich approach used by aircraft manufacturers. Car windows would have to be done this way too.
A 4 lb bird at mach
As far as I know, the problem with aircraft applications is that the set of requirements is lengthy:
- nearly shatterproof at high speed.
- impervious to cold, changes in density, including fogging.
- able to withstand repeated pressurization/depressurization
- ability to resist bird strikes.
Tall order. Most modern aircraft (both civil and military) use a poly/glass/poly sandwich, with a thin wire mesh for increased stability.
Other problem is from bulletproofing -- polycarbonate loses its strength over time. I think it's offgassing. Anyway, for this reason, bulletproof glass loses its rating after some time, and has to be replaced. I've seen a
Yes, the muzzle area for the birdgun is a mess of vaporized bird. and it smells funny.