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Electrically Conductive Cement 159

zero_offset writes "The Tokyo Institute of Technology has announced a process for creating an inexpensive, nearly transparent, electrically conductive alumina cement. The conductivity is comparable to metal, and the transparency should be adequate for use in display panels. The process relies upon commonplace and inexpensive metals compared to the rare metals such as iridium currently used in display panels."
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Electrically Conductive Cement

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  • Indium (Score:4, Informative)

    by nuzak ( 959558 ) on Wednesday April 11, 2007 @08:26PM (#18696977) Journal
    RTFA, the rare metal in LCDs is Indium, not Iridium.
  • Cement != concrete (Score:5, Informative)

    by jfengel ( 409917 ) on Wednesday April 11, 2007 @08:31PM (#18697015) Homepage Journal
    Cement = anything used to glue things together

    Concrete = a building material composed of aggregates and cement

    Concrete is used for buildings, roads, sidewalks, etc. The aggregate in that case is usually rocks. The cement is usually Portland cement. It's not correct to call it "cement", though people will usually understand what you mean.

    But judging from the comments so far, not in this case. This isn't a replacement for Portland cement, and they're not talking about building materials. This is the kind of cement used to glue bits of LCD screens to each other.
  • Home circuit fabs? (Score:5, Informative)

    by Teancum ( 67324 ) <robert_horning AT netzero DOT net> on Wednesday April 11, 2007 @08:43PM (#18697113) Homepage Journal
    When I read this, I was thinking of Fab@Home [] with the idea that perhaps you could use this process to help build crude home-built ICs out of simple and cheap materials.

    Unfortunately, it seems as though the process is a bit more complicated, and I don't know how you can get a nozzle heated to 1100 degrees C in a reduced oxygen environment (presumably why it is in a sealed glass tube to work) that would also be something you would want on your kitchen table.

    While of interest to a materials science guy, this really isn't that spectacular of a deal here. It does have the potential of improving LCD screen luminance values, reducing power requirements for laptops (the screen sucks quite a bit of power in the overall system), and helping in other ways. But it isn't something that simply can be poured out of a nozzle.
  • by freefrag ( 728150 ) on Wednesday April 11, 2007 @09:10PM (#18697269)
    Urine streams do not conduct electricity because they separate into droplets.
  • by dr. loser ( 238229 ) on Wednesday April 11, 2007 @09:46PM (#18697499)
    The author of the actual paper is Hideo Hosono [], not "Hideo Hono". The paper, available here [], was not published in the April 11 issue of Nano Letters. Rather, it was published on-line on March 22.
  • Re:cheaper tvs? (Score:3, Informative)

    by Teancum ( 67324 ) <robert_horning AT netzero DOT net> on Wednesday April 11, 2007 @09:51PM (#18697541) Homepage Journal
    I guess many of those posting havn't heard about Rubber cement [], commonly used for building model vehicle kits. Or other kinds of cement like the solvent used in PVC pipes.

    While making it cheaper may be true, the big problem that happens with displays is that you have wires which cross between pixels on any display.... simply to turn the pixel "on" or "off". These can be quite thin and are made of several different kinds of materials, but they do get into the way of the display. By making these wires transparent, you would have a huge increase in the throughput of the light coming from something like a back-lit light source (common for laptops).

    As far as replacing Indium or other rare earth metals... I don't understand that at all. Those metals are used to floresce in a CRT (television picture tube) and produce color pixels. This is what makes the TV be in bright colors. This article on color televsion [] gets into some of the specific color properites of Indium compounds and how they enhance the color gamut that can faithfully reproduce color from electronic media. This cement is not going to have those same kind of properties.
  • by abushga ( 864910 ) * on Wednesday April 11, 2007 @09:55PM (#18697567)
    The acronym is TiTech. These kids design pico-satellites and put them into low earth orbit, among other things.
  • by freefrag ( 728150 ) on Wednesday April 11, 2007 @10:13PM (#18697671)
    Yah, Mythbusters busted that one.
  • Re:cheaper tvs? (Score:3, Informative)

    by glesga_kiss ( 596639 ) on Wednesday April 11, 2007 @11:02PM (#18697977)

    As far as replacing Indium or other rare earth metals... I don't understand that at all.

    I believe the main benefit is the cost of Indium and similar substances.

    specific color properites of Indium compounds and how they enhance the color gamut

    This substance isn't intended to be part of the light emitting (or blocking) part of a display. It's for the wiring to those parts, built into the screen. By making it more transparent, the light level required can be reduced which saves battery life in laptops and possibly the cost of the light components.

  • Uhm... Old News? (Score:3, Informative)

    by Wandering Wombat ( 531833 ) <mightyjalapeno AT gmail DOT com> on Thursday April 12, 2007 @12:36AM (#18698417) Homepage Journal
    I did a college engineering report on this... in 2004.
  • by mrchaotica ( 681592 ) * on Thursday April 12, 2007 @01:03AM (#18698541)

    Does anybody else remember the conductive LEGOs introduced with the 9V system?

    Uh, I don't know about yours, but my 9V LEGOs (such as in the monorail) weren't electrically conductive themselves; they just used regular plastic blocks with metal bits embedded in them. For example, see the pictures on this site [].

  • Re:cheaper tvs? (Score:3, Informative)

    by Teancum ( 67324 ) <robert_horning AT netzero DOT net> on Thursday April 12, 2007 @01:34AM (#18698685) Homepage Journal
    I highly doubt that the value of the 2 grams of Indium used for a display is going to be a major factor in the overall cost of the display. You could use Gold or even Iridium and it wouldn't even be a factor. Californium, perhaps, but that element is sold by the gram. I just don't buy that as a serious argument.

    Trust me when I say that it is the use of Indium compounds and their phosphorescence at bold primary colors that makes it so valuable, and is driving up the world market price of Indium. Compared to Gold, Indium is a lousy conductor. A Gold or Silver trace would be much easier to hide because you would not have to use as much material. The use of Indium as a wire is not the issue, although the amount of the Indium compounds could be reduced slightly in a matrix of this cement and other composite materials used in a display system. That would be something that would appeal to a CEO or bean counter that is really concerned about the expense of getting Indium on the world metals market, but the concern would be about simply getting bulk Indium in the first place.
  • by Proofof. Chaos ( 1067060 ) on Thursday April 12, 2007 @05:31AM (#18699853)
    OK, my buck oh five.

    First, the dictionaries suck. American Heritage also gives cement=Portland cement, or even concrete before cement=glue or binder. This is wrong. The use of the word cement to mean Portland cement -used to make concrete- or worse yet concrete itself, is essentially slang. Its like calling network cable "copper," or fiber-optic cable "fiber." Why they give that definition before "A substance that hardens to act as an adhesive; glue," and "Something that serves to bind or unite," I don't understand. For the best explanation, please see Wikipedia: []

    Please people, stop telling people you have a "cement" sidewalk and an "asphalt" driveway (or worse yet, tar). You have a "concrete" sidewalk, and a "blacktop" driveway (or "asphalt cement" if you want to get really technical).

    Now, after rereading the article, I see that they say "lime-alumina" cement, which sounds like Portland cement to me, but then they say aluminum is used as a substitute for indium, which, AFAIK, is not used in Portland cement. So, I don't know WTF to think they mean.

"How many teamsters does it take to screw in a light bulb?" "FIFTEEN!! YOU GOT A PROBLEM WITH THAT?"