IGZO: Vision for the Future [a special advertising section by Sharp Electronics Corporation (US) in The Wall Street Journal, Jan 7, 2013] which was timed for the CES 2013 opening and was used as a detailed landing site for banners put everywhere like here with this view as of Jan 20, 2012:
[written by Bill Machrone on assignment from Sharp Electronics Corporation (US)]
Liquid crystal display (LCD) performance is about to take another leap forward. Existing LCDs have given us remarkable quality in HDTV, tablets and smartphones, as well as reasonably low power consumption. But Sharp Corporation is on the verge of delivering a new technology that will enable much higher resolution and significantly lower power consumption. More
The hunger for display resolution will probably never be satisfied until displays are indistinguishable from a printed page and as nuanced as a watercolor. IGZO takes a large step in that direction by enabling very high pixel-per-inch counts on small displays and Ultra-High Definition on larger monitors, while retaining brightness. More
The great thing about a technological breakthrough like IGZO is that it makes dreams come true. Yesterday’s dreams, today’s dreams, tomorrow’s dreams. More
– Sharp-er Hon Hai / Foxconn [this same ‘Experiencing the Cloud’ blog, March 31, 2012]
– IGZO microsite of Sharp Electronics Corporation (US) from which I will embed here the following video:
– IGZO [sharpelectronicsusa YouTube channel, Jan 3, 2013]
Excerpts from IGZO: Vision for the Future
[a special advertising section in The Wall Street Journal, Jan 7, 2013
written by Bill Machrone on assignment from Sharp Electronics Corporation (US)]
… if you just want to understand on a single page this latest LCD technology advancement vs. Hydis: its FFS succeeding IPS [core information page on this same ‘Experiencing the cloud’ site, May 11 – Oct 12, 2012] or the earlier AH-IPS technology from LG Display and True HD IPS of LG Mobile LTE superphones: Nitro HD (AT&T) and Spectrum (Verizon) [‘Experiencing the cloud’, Jan 19, 2012], or the even more earlier Plane to Line Switching (PLS) screen technology (Samsung) [‘Experiencing the cloud’, Oct 2, 2011] which is essentially the same as the well established IPS [Wikipedia] technology.
IGZO transistors have high electron mobility and much lower leakage current characteristics than the two dominant silicon TFT processes. IGZO TFTs are smaller, so displays can have higher resolution with less loss in light transmission. Based on the license from the Japanese Science and Technology Agency, Sharp’s breakthrough is the large-scale manufacture of IGZO panels, effectively moving the technology into the hands of manufacturers and consumers. Furthermore, Sharp Corporation and Semiconductor Energy Laboratory Co., Ltd. jointly developed a new oxide semiconductor (IGZO) technology with high crystallinity.
Low power consumption is critical for portable devices. IGZO TFTs have dramatically lower leakage current when the TFT is off. When static, non-video content is being displayed, IGZO can also operate in a mode where pauses are inserted between the drive/refresh cycles, with almost no flicker. The result is further reduction in power consumption. Designers can then build devices with increased battery life, smaller size or both.
Your HDTV has approximately two million pixels, each made up of a red, blue and green subpixel, and each subpixel has a TFT transistor that causes the subpixel to change from opaque to transparent. UHDTV has four times the resolution, which requires four times as many pixels, approximately 4000 across and 2000 down. And yes, three subpixels per pixel.
An IGZO TFT can pass 20 to 50 times more electrical current than an equivalent amorphous silicon TFT. That’s far more than the LCD cell actually needs, so it can be much smaller. Smaller size is essential to retain brightness, or the body of the transistor would block too much light in a smaller LCD cell. The required current to operate each TFT is lower too, so the mesh of printed wiring that interconnects the transistors and defines the walls of the cells can be thinner. This contributes to overall brightness, as well.
Although a UHDTV might still be workable with larger transistors and lower transmittance, it would require a brighter backlight, which in turn consumes more power.
Higher resolution in portable devices can be very costly in terms of power consumption. Consumers always want the least weight and the greatest battery life. IGZO is the ideal solution.
The graph below shows the dramatic benefits of IGZO compared to the other competing TFT technologies. The curves illustrate the amount of current flowing as the gate voltage, which switches the transistor from its off state to its on state, is increased. For comparability, Sharp engineers standardized the size of the transistors.
Amorphous silicon (a-Si) has a respectable difference in on-current to off-current, roughly a million to one, or 106. But it has relatively high leakage, which increases power consumption.
Low-temperature polysilicon (LTPS) excels at delivering high current; it has excellent electron mobility. Unfortunately, it also has higher leakage. Its ratio of on-current to off-current is 107, somewhat better than a-Si.
IGZO has electron mobility nearly as high as LTPS, but its leakage current is vastly lower. The ratio of on-current to off-current is a phenomenal 109, essentially a billion to one. Low leakage current, combined with physically smaller size, makes it a clear winner for smartphones and tablets.
Low leakage current creates the potential for a new operating mode for LCD panels. Currently, the panel needs to be refreshed or “driven” continually because leakage current causes the cell to discharge. Too long a delay in refreshing the image would cause undesirable effects such as flicker or color shift. Although video images need to be refreshed continually, static images such as menu screens, documents and still photographs don’t. Because IGZO LCD panels can retain their active state longer, it’s possible to save additional power by skipping drive cycles. The benefits for tablets and phones, which often display static menus and pages, are obvious.
Although preliminary, this chart illustrates the potential for power savings:
Because the drive need not be continuous in an IGZO display, touch-sensitive displays can become more sensitive. Noise is a natural byproduct of any transistor switching on and off, and the millions of them in a display create a steady background noise, as shown in the graph on the left, below. The voltage spike caused by touching the panel is hard to detect. By interleaving the drive and touch detection cycles, touches are much easier to detect, as shown in the next graph. For conventional finger-detection displays, the touch-sensing layer of the panel can be thinner. Touch panels tend to have difficulty detecting stylus input because the signal generated by the stylus tip is small compared to that of a fingertip. With the pauses, however, stylus detection becomes easier and more accurate, which is critical as resolution and display density increase.
As you can see, the benefits of IGZO interlock nicely with the improvement of existing products and the development of new ones.
KDDI, a Japanese telecommunications company, has just released the AQUOS Pad, which uses a 7-inch IGZO display. Preliminary testing suggests that its low power consumption gives as much as three times the battery life of previous model tablets.
The Aquos Phone Zeta, released from NTT Docomo, is the first smartphone with an IGZO display. Now shipping in Japan, it has a 4.9 inch 1280 x 720 display and equally rich camera, processor and memory features to make it a premium phone with excellent battery life, over four and a half times more than a previous year’s model.
Softbank Mobile will also be releasing a smartphone in Japan with an IGZO display in March. The products mentioned above are manufactured by Sharp Corporation.
Users of professional monitors are a breed apart from most business users. They include photographers, graphics designers, engineers using CAD, radiologists, video editors, and even analysts with complex charts and high-density numeric data. Some of these users employ multiple monitors when what they really need is higher display density. Sharp has unveiled its landmark PN-K321 monitor, a 32-inch (31-1/2 inch diagonal) 4K (Ultra-High Definition) monitor, with QFHD 3840 x 2160 resolution. It will be available in Japan in February. This new monitor applies IGZO’s smaller device geometry to a current problem, a real product when many others are just showing very limited products.
Today’s prototypes are tomorrow’s products – realities, not dreams. And the ones that Sharp has shown to date are tantalizing, indeed! In the latter part of 2012 Sharp displayed a 6.1-inch LCD with an astounding 498 pixel-per-inch resolution, 50 percent greater than one of the most highly touted displays of 2012. They also displayed a 13.5 OLED inch screen with the same 3840 x 2160 resolution as the 32-inch (31-1/2 inch diagonal) monitor above. On the smaller screen, that’s 326 pixels per inch, a resolution that has to be seen to be appreciated.
Sharp has also demonstrated flexible displays, using IGZO to drive OLED (organic light-emitting diodes). OLEDs don’t require backlight and their application overlaps with LCD in some areas, but each has specific strengths. Remarkably, IGZO improves the performance of both technologies.
For those who have seen the prototypes, tomorrow can’t come soon enough. The demand for resolution in all applications, from smartphones to wall-sized displays, is strong and getting stronger every day. Sharp has equipped its world-renowned Kameyama plant to produce IGZO panels, in ever-increasing size and volume.
Sharp has invited its designers, engineers and scientists to dream big, to think about a world without constraints on connectivity, with sensitive biometrics, with technologies that extrapolate the potential of IGZO, with materials that haven’t even been invented yet.
They have envisioned a future in which any working surface in your home or office can be both a display and touch-sensitive input device. Your bathroom mirror (or any room or appliance) can recognize you and adapt or adjust itself to your needs or preferences. Because IGZO lives behind glass, has extremely low quiescent power requirements, and can work cooperatively with sensitive measurement and sensing technologies, your environment can monitor your health and welfare as never before. An area on the floor can replace your bathroom scale; it can check your pulse, your temperature, calculate your body mass index, and more.
A table is no longer a table. It’s a newspaper, it’s a magazine, it’s a TV. It’s a research library, it’s a homework station. It’s a telepresence device, it’s an artist’s canvas, it’s a display for your favorite photos and images.
A myriad of IGZO transistors and sensors woven into a fine, fabric-like mesh can become part of our clothing. It can monitor our workout and help to diagnose our illnesses. Sensors in the kitchen can verify the freshness of our food and give us real-time information on nutrition.
The low power requirements of IGZO make self-powered devices more of a practical reality. Small devices may be solar-powered, running on ambient light. Devices that require more power may be charged wirelessly.
This is the future that we want; this is the future that we need.