PPI - Page 21

Cambridge Display Technology and Toppan Printing, the leading information and communications company of Tokyo, Japan, have produced a number of 5.5 inch full color active matrix polymer OLED (PLED) displays using a roll printing method. A demonstrator will be shown at the SID conference in San Francisco. The displays - believed to be the first of their type ever produced - are the result of close co-operation between the two companies and part of their joint development activity announced in February 2005.

Solution processing of PLED (also called P-OLED) displays is more commonly associated with inkjet printing, and the companies believe that roll printing represents a promising alternative production technique which offers the potential for very good display uniformity, very high display resolution and low capital and operating costs. In the future, this type of roll printing process could be well suited for making flexible P-OLED displays. CDT believes that this combination of properties can only be achieved with solution-based printing processes.

Universal Display will unveil a new deep red PHOLED material system with excellent luminous efficiency, 15 candelas per Ampere (cd/A), that corresponds to 19% external quantum efficiency.
In addition, the Company is reporting advancements in device architecture designs that lead to significantly extended lifetimes.

The Company is also demonstrating novel device architectures that provide significant enhancements in color saturation. By comparison to yellow-green color in a standard bottom-emitting OLED structure, the same PHOLED material system offers a saturated green color, with CIE coordinates of (0.25, 0.72), in a cavity-tuned, top-emission structure. (In a bottom-emitting structure, this system offers luminous efficiency of 71 cd/A and 100,000 hours of operating lifetime at 1,000 cd/m(2).)
As will be reported, Universal Display has developed device architectures to improve the luminous efficiency of its sky blue PHOLED material by 50%, to 30 cd/A, with 100,000 hours of operating lifetime at 200 cd/m(2).

Dr. Anna Chwang will present advances in the development of a top-emitting, active-matrix OLED display built on flexible metal foil using the Company's proprietary OLED technologies. The 100 ppi QVGA OLED display is integrated onto a poly-silicon TFT backplane developed by Palo Alto Research Center (PARC).

NTERA and Seiko Epson today announced they have successfully produced working prototypes featuring the world's highest resolution naturally reflective electronic displays using NTERA's visualDNA(TM) brand electrochromic display technology. The prototypes feature 200 dpi and 400 dpi QVGA resolution and were produced using Epson's solution processable inkjet methods.

NTERA's technology reflects any ambient light, including bright sunlight, to make images always visible. It features ink-on-paper appearance at a fraction of the power consumption of existing electronic displays by eliminating backlights, a significant power drain in mobile devices. "Existing LCD and emerging OLED technologies fight the sun - we use it!" said Mr. Ritz.

In the paper titled Full Color 100 dpi AMOLED Displays on Flexible Stainless Steel Substrates, Dr. Anna Chwang will highlight the performance characteristics of a novel flexible, full-color AMOLED display prototype that is based on the Company’s proprietary phosphorescent OLED (PHOLED™), top-emitting OLED (TOLED®) and flexible OLED (FOLED®) technologies. The full-color AMOLED prototype also uses LTPS TFT backplanes designed and fabricated by PARC, a subsidiary of Xerox Corporation, and was encapsulated by Vitex Systems.

The four-inch diagonal display can portray a variety of images, including full-motion video. This advance is significant in proving the fundamental feasibility of the Company’s approach and also clearly demonstrates several key performance advantages. The display (without external drive electronics and package) is approximately 0.1 mm thick and weighs a mere 6 grams. The comparable glass-based LCD would be approximately 1.0-1.5 mm thick and weigh 20-30 grams. Research and development activities are continuing in a number of areas including enhanced display flexibility, defect elimination and enhanced electronics capabilities

Using plastic instead of glass substrates enables panel manufacturers to create bendable, flexible LCDs for mobile and consumer electronics applications. Samsung claims it has created the largest flexible display to date: The 7-inch prototype achieves VGA resolution.

On the performance side, the display 640 x 480 pixel resolution (VGA) at 114 ppi, which is in line with other types of bendable displays. The aperture ratio of the device is rated at 40 percent, the brightness at 100 nits and the color saturation at 60 percent. Samsung claims that the specs are sufficient to make plastic substrates a viable alternative to glass substrates even for digital TVs.
Flexibility is considered to be the next major step for LCD technology. Used already in Japan in the advertising industry, bendable screens are typically based on OLED variants. For example, Fujitsu recently announced an OLED-based "electronic paper," that includes non-volatile image memory, which can store and display a static color image without power supply.

Its no secret that the Shadow Masking Process, widely used today, for OLED production has its resolution limitations. The highest resolution achieved by the process is around 170ppi. AUO has overcome this industry hurdle and revolutionized a pixel design that progresses the resolution of OLED to reach VGA grade standards (640 RGB x 480). AUO will debut this latest technology in its 3" VGA AMOLED prototype with resolution as high as 270 ppi (pixel per inch), bringing OLED resolutions to new level highs. With the added ultra high resolution, the panels are ideal for portable multimedia player (PMP), mobile phones, DSC, and DVC alike. Dr. JJ Lih, Director of OLED Division at AUO noted, " Our revolutionary design has been a breakthrough in dramatically improving resolution levels, without having to increase costs. Not only were we able to successfully improve our 3" AMOLED panel to VGA grade but we've also managed at the same time to maintain contrast ratio to >10,000:1 and fast response time

Canon has demonstrated a prototype digital SLR camera using an OLED display, which will help extend battery life and be easier for photographers to view. Unlike traditional LCD screens, which use coloured filters and a backlight, an OLED generates its own light. This improves the screen's viewing angles and lowers power consumption, both of which are very useful for digital cameras.

Canon’s OLED demonstration used a 2.4" screen with QVGA (320 x 240) resolution, which delivered a bright and detailed image with 167 pixels per inch (ppi).

Universal Display Corporation today announced the development of the world's first high-resolution, active-matrix, transparent OLED (AM-TOLED) display using the Company's PHOLED phosphorescent OLED and TOLED® transparent oled technologies along with amorphous silicon (a-Si) backplane technology developed by Professor Jin Jang at Kyung Hee University in Seoul, Korea.

The development of this high-resolution transparent OLED display is a step toward putting thin, low power, full-motion video displays that provide transparency when turned off into a variety of applications where preserving partial visibility or bi-directionality is important. These include architectural vision glass, entertainment, medical and industrial products, helmet shields for military, Homeland Security, fire and rescue applications, and other applications as yet unimagined.

AU Optronics Corporation has introduced Double Sided Active Matrix OLED. This technology allows showing simultaneously, two separate images, moving or still, with 143 ppi (pixel per inch) resolution and 200 nits (cd/m2) brightness, on one panel. With specifications of less than 1 ms response time, contrast ratio of more than 1000:1, and viewing angle of >170 degrees, it is suitable for small sized consumer electronics solution.

AU Optronics says they have developed a breakthrough technology - a double sided AMOLED that can show two separate moving images on each side of the panel.

The new AMOLED features 143 ppi and 200 nits (cd/m2) brightness. AUO says that such displays can be used in mobile phones as a dual display.