Omron Corporation (TSE: 6645) has developed the world’s first* frontlight manufacturing technology capable of making brighter, clearer liquid display screens while reducing power consumption for wireless handheld’s, PDA’s and other mobile information terminals. The new technology will be on exhibit from October 7 – 11 at the CEATEC JAPAN 2003 show to be held at the Makuhari Messe near Tokyo in Chiba Prefecture.
The frontlight manufacturing technique, which applies nanotechnology, achieves athree-fold improvement in contrast ratio compared to frontlights manufactured by othercompanies, and screen brightness rivaling that of notebook computers (100cd/m2) throughhighly efficient light control.
Conventional frontlight methods have featured low power consumption but with low contrast(blurred picture), while backlight methods have featured high contrast (sharp images) butwith high power consumption, thus contradictory approaches.
By proprietarily developing the world’s first hybrid integration technology combining anano prism array with a micro prism array into a frontlight, low power consumption and abright, clear liquid crystal display screen are both possible.
With the spread of camera equipped mobile phones and video image transmission, marketdemand for brighter, clearer mobile phone as well as PDA liquid crystal display screenshas grown increasingly more. The mobile phone is no longer used only as a phone but as aninformation terminal and a mechanism for reducing energy consumption is necessary in theface of a greater trend toward screen energy consumption. Omron developed this newfrontlight manufacturing technology as a solution to these two needs.
Focusing on heavily demanded optical control technology following electrical controltechnology, Omron will concentrate on micro lens arrays, optical control devices and otherdevelopments.
* According to in-company research.
- Micro prism array realizes higher brightness, highly efficient control of LED light
- Nano prism array prevents reflection of unnecessary light, realizes clear screen images
- Proprietary design technology and fine processing technology realize reduction in numberof LED’s and lower power consumption
2) Performance comparisons
Omron’s frontlight Other frontlights Other backlightsPower consumption (mA) 20 30 60Contrast ratio 55:1 15:1 50:1Display brightness (cd/m2) 100 30 100Technology explanation
Omron created the world’s first technology mixing together nano prism arrays (size: 200nm)and micro prism arrays (size: 3um) on the frontlight.
1.) Micro prism array
Utilizing proprietary vector radiation coupling technology enabling highly efficientcontrol of light emitting from backlight installed LED’s, Omron has since developed andpossesses technology for brightening liquid crystal display screens.
With this vector radiation coupling technology, a micro prism array is designed in theupper surface of light (backlight or frontlight), allowing the path down which the lighttravels to straighten, thereby spreading all the light from the LED’s throughout theliquid crystal and making it possible to control the emission point and emission angle ofthe light radiating from the liquid crystal display screen. This eliminates the maximumamount of light loss, achieving a brighter screen [Diagram #1].
However, by applying the micro prism array to the frontlight in this way, light thatenters the frontlight from LED’s or from outside such as sunlight will cause reflection(optical noise) in the upper light surface or lower light surface of the frontlight. Lightcoming from the liquid crystal display screen will blend with this optical noise, leadingto decreased image quality (drop in contrast) and no frontlight diffusion despite lowerpower consumption [Diagram #2].
2. Nano prism array
Optical noise is produced across the material interface at two different refractiveindices. However, if the very fine nano prism array, with a size less than half that of anoptical wavelength, can be formed in the facing surface, reflected light can be reduced[Diagram #2].
Applying this theory, Omron created a 200nm (half the size of the shortest wavelengthamong light’s three primary colors – the blue light wavelength is 400nm) nano prism arrayin the facing surface of the frontlight.
Doing this enabled control of the optical noise produced on the frontlight interface,realizing a high contrast, clear image display.
3. Hybrid integrated technology
Omron succeeded in developing the world’s first hybrid integrated technology that fusesmicro prism arrays with nano prism arrays. This technology takes both micro prism arraysand nano prism arrays, characterized by a several ten-fold size disparity in patterns, andunites them into one development.
The realization of a bright liquid crystal display screen through micro prism arrays andthe realization of near zero reflected light, high contrast and clear image through nanoprism arrays are the features integrated into a frontlight for the first time, achieving abright, clear, low energy consuming frontlight.
About Omron Corp.
Headquartered in Kyoto, Japan, OMRON Corporation (TSE: 6645) is a global leader in thefield of automation. Established in 1933 and headed by President Hisao Sakuta, Omron hasmore than 23,000 employees in over 35 countries working to provide products and servicesto customers in a variety of fields including industrial automation, electroniccomponents, social systems (ticket gate machines, ticket vending machines, cashdispensers, and traffic control), and healthcare. The company is divided into five regionsand head offices are in Japan (Kyoto), Asia Pacific (Singapore), China (Shanghai), Europe(Amsterdam) and US (Chicago).For further information, please visit the Omron Corp. homepage at: www.omron.com