Sharp præsenterer komplet program af low-power LCD'er
Sharp kan nu tilbyde et omfattende program af LCD med integreret 1-bit hukommelse i hver pixel, hvilket kan reducere effektforbruget med op til 99 procent i sammenligning med konventionelle TFT LCD'er (in english).
In addition to the 1.35-inch model (LS013B4DN02) introduced middle of last year, Sharp is introducing further Memory LCDs in new sizes: two 2.7-inch (LS027B4DN01, LS027B4DH01) displays with a resolution of 400 x 240 and a 2.94-inch (LS029B4DN01) model with a resolution of 456 x 240 pixels.
Later on in the first half of this year, Sharp is also planning the introduction of a 6.02-inch model in order to specifically address the e-books market and other portable reading devices. For this particular market segment, Sharp is aiming to supplement the range with transflective and touchscreen models in the second half of the year.
Unlike the usual reflective memory LCDs, transflective memory LCDs offer the option of adding backlighting so that e-books or other applications can also be used in the dark. The Memory LCDs with touchscreen ensure that these devices are user friendly. Thanks to the capacitive touchscreen, e-books can be designed in such a way that readers can turn the pages almost like a paper book.
In addition, a 4.4-inch model is in preparation for the autumn.
Based on CGS technology
These innovative System LCDs are based on Sharp's own Continuous Grain Silicon (CGS) technology. This enables it to equip each pixel with a 1-bit memory that stores the image information uploaded onto the screen. Image information therefore only needs to be rewritten in those pixels in which the content has changed compared to the previous picture frame.
As reflective displays, Memory LCDs do not require any backlighting. The combined effect means that memory LCDs only have 0.8 percent of the power consumption of conventional displays of the same size. In contrast, with conventional LC displays, micro-controllers have to rewrite the entire screen content from frame to frame at a speed of 50 to 60 Hz, even if most of the image content remains the same.
In addition, the backlight accounts for a good proportion of the power consumption. Standard LCDs thus have a power consumption that is around 130 times greater than that of the newly developed memory LCDs. A 1.35-inch memory LCD uses 15 µW in operation, whereas a standard LCD of comparable size requires around 2 mW to display an image. Even the 6.02 inch model only needs up to 3.5 mW at a frame frequency of 1 Hz.
In addition, the memory LCDs offer a unique image representation. Unlike other reflective displays, this new type of LCD does not require any polarisers. Thanks to a special Polymer Network Liquid Crystal (PNLC) material, the image is generated by the status of the pixel changing from transparent to white with a reflectivity of 50%.
This gives the display a silver-metallic appearance that is particularly suited to fashionable applications. With a slightly more conventional version of the memory LCDs, polarisers and high-reflective (HR) liquid crystals are used. They supply a purely black-and-white image with superb legibility and a very broad viewing angle.
Through their minimal consumption of power, small solar cells can supply sufficient electricity to run the new Memory LCDs. The new type of display is thus an ideal solution for small portable applications such as, for instance, e-books, wristwatches, heart rate monitors and other fitness devices, shelf labelling, etc. With solar cells as a source of power, such systems can even be designed as self-sufficient applications.
In order to simplify the design-in for such energy self-sufficient solutions, Sharp also offers memory LCDs as 3-volt models so that when operated with conventional lithium ion rechargeable batteries, no charge pump is required in between. The new 6.02 inch display is already designed for this supply voltage and four other memory LCDs that are expected to be launched on the market in the second half of 2010 also only require the lower supply voltage.
The new memory LCDs are already available in 1.35-inch, 2.7-inch and 2.94-inch diagonals from the sales offices of Sharp in Europe and through distributors. Samples of the 6.0-inch models are anticipated to be available in Q2 2010.
Picture: Sharp is offering its new Memory LCDs for low-power applications in two technology variants: The high-reflective (HR) models (left) can be read very well from all sides, whereas the PNLC models (right) provide a silver-metallic appearance and are thus also suited for fashionable applications.
