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Displays Upgrades Technology

Display Makers To Use Quantum Dots For Efficiency and Color Depth 100

ArmageddonLord writes with this news from the IEEE Spectrum, reporting on display industry gathering Display Week: "Liquid crystal displays dominate today's big, bright world of color TVs. But they're inefficient and don't produce the vibrant, richly hued images of organic light-emitting diode (OLED) screens, which are expensive to make in large sizes. Now, a handful of start-up companies aim to improve the LCD by adding quantum dots, the light-emitting semiconductor nanocrystals that shine pure colors when excited by electric current or light. When integrated into the back of LCD panels, the quantum dots promise to cut power consumption in half while generating 50 percent more colors. Quantum-dot developer Nanosys says an LCD film it developed with 3M is now being tested, and a 17-inch notebook incorporating the technology should be on shelves by year's end."
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Display Makers To Use Quantum Dots For Efficiency and Color Depth

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  • Re:Quantum dots? (Score:5, Informative)

    by Scytheford ( 958819 ) on Saturday June 16, 2012 @05:18AM (#40343093)

    Actually you're dead wrong. Quantum dots are A Thing. Here's how to make them in a basic lab: http://www.youtube.com/watch?v=bNuoYm7Su4o [youtube.com]

  • by Anonymous Coward on Saturday June 16, 2012 @05:47AM (#40343143)

    A pure color is light with a narrow spectral bandwidth. It doesn't matter which color, just that there is ONLY that color.

  • Re:Quantum dots? (Score:5, Informative)

    by Scytheford ( 958819 ) on Saturday June 16, 2012 @06:11AM (#40343189)

    Because the energy levels of the electrons are at quantum levels. They transition between these levels and emit light. This is an absolutely correct usage of the word "quantum". You are a foolish troll.

  • Re:Quantum dots? (Score:2, Informative)

    by Anonymous Coward on Saturday June 16, 2012 @06:15AM (#40343199)

    Perhaps because they're semiconductor particles whose electronic properties are size-determined due to quantum confinement, rather than bulk material properties.

  • by Anonymous Coward on Saturday June 16, 2012 @07:23AM (#40343373)

    If you're going to call somebody out for being wrong, you might want to actually do some research. Those 1024x768 pixels are made up of basically triple that in terms of red, green and blue sites that emit the actual light. If you replace those with ones that can handle the entire gamut you would need a third of them and you lose the overhead from having to have individual shutters on each one.

  • by Kjella ( 173770 ) on Saturday June 16, 2012 @07:46AM (#40343421) Homepage

    Well, yes and no the chart is technically not wrong if you have a single frequency light source like a laser. The trouble is that most real world objects emit a spectrum of light. This chart [wikimedia.org] shows the cone response relative to frequency so the cone's response is an integral over the spectrum*sensitivity. The problem is that in all commonly current display technologies (CRT, LCD, LED, OLED, 3-chip DLP) you only have a fixed number of frequencies to work with. For example say you have red (600nm), green (540nm) and blue (440nm). Well, it turns out you can't actually produce all combinations with just three wavelengths as real world objects do with infinite wavelengths.

    The reason for this if you look at the response chart is that the curves overlap, you can't simply decompose them into three components you can set individually. Any wavelength you send to stimulate the M cones also stimulate the S or L cones. And our vision is particularly good at picking up on those differences, it's a two-stage process like illustrated here [wikimedia.org]. Even if the mix in the SML cones is mostly right the Cg and Cb cells are extremely good at picking up on differences in the relative mix. Ideally you'd like more wavelengths or white light + a color wheel like used in single chip DLP, but it's not that easy and you need a signal with the extended information like xvYCC.

  • Re:Quantum dots? (Score:5, Informative)

    by Anonymous Coward on Saturday June 16, 2012 @10:17AM (#40344013)

    The term is related to Quantum Well and Quantum Wire. A quantum well is a system where particles (electrons) are confined to move in 2D by two very large potential barriers on either side of the well. It's generally one of the first systems studied in quantum mechanics. Quantum wires are like quantum wells except the potential barriers also exist in a second dimension, so that the particle is confined to move in 1D along the "wire". A quantum dot is a small box which is confined by potential barriers in all directions so that the electron can only exist within the extremely small dot.

    Obviously quantum dots are going to be around the nm range so that they can actually confine the particles in any meaningful sense, but the point is the effects that QM predicts for that particular configuration. The size and shape of the dot allows us to precisely tweak the energy levels and wavefunction symmetries involved, something fairly particular to the "nano 3D potential barrier" system.

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