Sci-Tech-Prod (Science-Technology-Products) Village 科學技術產品村: 018: Fleible LCD 可彎曲軟性液晶顯示器

Fujitsu has developed a flexible LCD panel that can maintain the displayed image
even with no power supply, it says.

The cholesteric LCD panel, which is the name given to the technology that allows
the image to be maintained on-screen, measures 3.8 inches across the diagonal
and was on show Thursday at the company's Fujitsu Forum 2005 event in Tokyo.

It's the result of about 5 years of research, says Toshiaki Yoshihara, a senior
researcher at Fujitsu Laboratories' storage and intelligent systems laboratory, and
one of the developers of the panel. He estimates it could be ready for
commercialization in 2 or 3 years.

Two versions of the 3.8-inch display were on show. A powered, color display was
showing continuously changing images, with each screen refresh taking several
seconds, while a monochrome display that hadn't been powered for two weeks was
still showing its image.

Also on Display
Also on show were larger panels about 12 inches across the diagonal. They were
built on glass substrates and so weren't flexible. Fujitsu was showing these in a
mock bus-stop sign that continually changed to show the location of buses, the
timetable, and other information. The company has dreamed up a number of other
uses for the panels, including as electronic advertisements on trains and as
displays on smart cards.

Because they require very little power to refresh, the images can be changed by
drawing power from the weak radio waves used in contactless smart cards, like
those in use on many public transport systems around the world.

Fujitsu is calling the technology 'electronic paper' and also suggested, as do most
companies that propose flexible displays, that it might serve in the future as an
electronic newspaper. While the displays have high contrast and are flexible almost
like paper, they fall short in some areas: they can't be folded and they can't be
written on.

Cholesteric LCD panels are also being developed by other companies including
Philips Research. In addition, Kent Displays, based in Kent, Ohio, already offers
seven types of such panels including an SVGA-resolution (800 pixels by 600 pixels)
panel that measures 14.5 inches by 10.9 inches.

By Jennifer LeClaire
TechNewsWorld
11/28/05 1:34 PM PT

With its new display, Samsung said it has overcome daunting problems involving
the plastic substrate's heat sensitivity including a previous challenge to maintain the
display's substrate thickness when subjected to typical commercial thermal
conditions.

Samsung Electronics today said it has developed the world's largest transmissive
TFT LCD (thin-film transistor, liquid crystal display), with high enough resolution to
display digital television content. The new display is double the size of Samsung's
flexible LCD display prototype announced in January 2005.

Samsung said the seven-inch, 640x480 flexible display uses a transparent plastic
substrate that is thinner, lighter and more durable than the conventional LCD glass
panels used today. Moreover, the electronics giant said the full-color transmissive
LCD panel maintains a constant thickness even when it is bent.

Solving an LCD Challenge
Considered the next-generation in flat panel displays, this technology involves the
use of pliable plastic instead of rigid glass substrates in TFT-LCD production.
Samsung said the plastic will not break when flexed, allowing much greater
freedom in commercial designs requiring flexible full-color, high-resolution display
components.

ISuppli Vice President Paul Seminza told TechNewsWorld that there has been
significant research conducted in the area of flexible displays. That's because it has
been a challenging problem to solve since LCDs are designed with the liquid
crystal material sandwiched between two substrates.

"Typically when you flex an LCD it changes the spacing between those substrates.
The spacing is important to the operation of the LCD as a whole. When you flex the
display it looks different near the bend than it does at the edges," Seminza said. "So
figuring out a way to hold the spacing while enabling flexibility has been a big
challenge."

Low-Temperature Technology
With this advancement, Samsung said it has also overcome daunting problems
involving the plastic substrate's heat sensitivity including a previous challenge to
maintain the display's substrate thickness when subjected to typical commercial
thermal conditions.

Samsung said it has developed a low-temperature processing technique that can
be used to manufacture the display's amorphous thin-film transistors, color filters
and liquid crystals at process temperatures much lower than standard
glass-based, amorphous silicon (a-Si) technology.

Drawing on technology adopted for the production of low-temperature (less than
130 degrees Celsius) a-Si TFT LCD and color filter, Samsung said its proprietary
LCD technology minimizes substrate deformation by preventing not only changes in
thickness but also distortion of images by binding two extremely-thin panels
together through a new proprietary system design.

Targeting Mobile Displays
Samsung said the seven-inch flexible TFT-LCD is optimized for mobility
applications, including cell phones and notebook computers. The company said
system designers and OEMs also may apply the advanced Samsung display
technology to new applications, such as fashion-enhancing or wearable electronic
display designs, thanks to its differentiated flexible format.

Seminza said mobile applications make sense because mobile devices need to
have a rugged nature. If the LCD display is bendable, he said, then consumers
could throw it in a purse or satchel without worrying about pressure from other
items damaging the display.

"We are constantly looking at how people would utilize that flexible nature," Seminza
said. "Would manufacturers make equipment that actually has curves in it, like a
product that goes around your wrist or a wave shape on a cell phone? Or perhaps
something that wraps around an automobile dashboard that utilizes the curve of the
design? Those are all possibilities."

工研院突破技術，展出可適度彎曲的軟性彩色液晶顯示器，未來可應用於高階輕薄型手
機與PDA等應用上，設計出更具時尚感的產品。

工研院於7/4至7/6期間在台北世貿中心舉辦的台灣平面顯示器暨設備材料展中，展出最
新的研究成果──可彎曲軟性液晶顯示器及10.4吋的彩色電子紙。

工研院展出7吋彩色主動液晶顯示器，與一般顯示器不同的地方，在於捨棄傳統TFT LCD
以玻璃基板材質設計，利用兩個厚度比目前玻璃基板研磨最薄的0.2mm還薄的塑膠基板
作為上下顯示器基板材質，以具輕薄化特性塑膠基板研發出軟性，可彎曲的彩色液晶顯
示器。

工研院表示這項軟性顯示技術，未來將可以應用於高階手機與PDA上，相較於傳統硬性
的玻璃基板材質，新的軟性顯示器技術可以讓螢幕作適度的彎曲，以滿足特殊手機的設
計需求。

工研院技術推廣組組長劉春樑表示，去年工研院雖然也開發出軟性顯示器，但因為下基
板在技術上還無法使用軟性的塑膠材質，而仍需使用玻璃基板，因此使得軟性彩色液晶
顯示器的最終設計理想無法達成。但今年工研院採用低溫非晶矽薄膜電晶體陣列等新技
術，已可讓下基板採用軟性塑膠基板，同時也克服基板使用不同材質而產生的拉扯不易
對準問題。下一步工研院就要設法增加軟性顯示器彎曲度，朝最終能夠捲曲收納的目標
研發。

另外，工研院也展出10.4吋俗稱彩色電子紙的彩色膽固醇液晶顯示器，據工研院表示，
這項研發成果，不同以往採R、G、B三層層疊的製程設計，而是以噴墨或分道注入的方
式，將三種色彩的膽固醇液晶灌注在畫素中，以單層化設計讓液晶顯示器可以簡化設
計，同時也減少傳統一半的厚度，開發出更輕的電子紙產品。

這項電子紙研究成果，可啟動電壓讓液晶呈現靜態彩色顯示後，除非下次改變顯示內容
才需要再導電重新顯示，否則舊的內容顯示期間均不再需要導電維持，因此電子紙具備
省電的特性，適合用於廣告看板等週期性變動廣告內容的宣傳媒體上。

儘管工研院開發的電子紙具備省電特性，但是劉春樑表示，目前啟動電子紙顯示所需的
電壓仍然偏高，約需要40多伏特，在電壓上相較於一般產品仍然偏高，未來要克服的問
題就在於如何將電壓減低至25伏特以下，如此才能被市場廣為接受。

而除了軟性液晶顯示器與電子紙之外，工研院也在世貿攤位上展出可重覆使用的環保名
牌，可利用USB與電腦連接重新輸入名牌顯示內容，顯示期間不需耗電，因此不需使用
電池。