TDK Transparent Display
TDK is taking those transparent OLED screens we saw back in October and putting them into mass production. The 2.4-inch, QVGA (240 x 320) UEL476 display has a transmittance of 40 percent, but obscures light passing through the front so others won't be able to read your text messages from behind. Obviously, these aren't going to find their way into high-end Android handsets, but they may have a home in fashion phones like Lenovo's S800. And, you know, they seem perfect for SMS addicts who can't stop their thumbs from flying even while walking. Check out the full PR after the break.
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TDK Starts Mass Production of See-Through Type High-Definition Organic Electroluminescent (EL) Display

Tokyo, May 31, 2011 - (ACN Newswire) - TDK Corporation has started mass production of a newly developed see-through passive matrix type QVGA organic EL display (product name: UEL476) from this Spring, a world's first*.

Organic EL displays are formed through thin-film techniques, using organic material that emits light in response to an electric current. High brightness, wide viewing angle and other favorable characteristics make this display type very easy on the eye, and since it also achieves fast response, Organic EL displays have been adopted for wider use in flat panel displays. All organic EL displays from TDK employ the passive matrix principle. The newly developed see-through type is mainly intended for use as the main display panel in mobile phones and other mobile devices.

The see-through type organic EL display for mobile applications has a field angle of 2.4 inches, transmittance of 40 percent, and brightness of 150 cd/m2. Compact mobile electronic devices such as mobile phones these days require a display that is appealing also from a design point of view. The newly developed product is a see-through type, but is constructed so that the display contents cannot easily be seen from behind, to protect the user's privacy.

TDK started developing organic electroluminescent materials in 1991, establishing an in-house R&D framework covering the entire process from molecular structure design to chemical composition and device evaluation. As a result, a proprietary long-life material and thin film layer configuration, as well as an optimized mass production process were developed. Development of a white organic EL element was started in 1995, culminating in a final product in 2000.

The use of the color filter principle means that the service life of the each Red, Green and Blue color of RGB elements is identical, and color shift is absent. Furthermore, favorable temperature characteristics allow a wide operating temperature range from -20 to +85 degrees C.

Development efforts are ongoing, with a view to widen the range to include various color products, as well as towards further improving precision and longer service life for all types.

Glossary

-- Passive matrix drive principle: One of the methods used to drive organic electroluminescent elements. A grid of vertical and horizontal electrode lines is used to drive a line of pixels each. By contrast, an active matrix display uses a dedicated TFT (thin film transistor) to drive each pixel separately.
-- QVGA: Abbreviation of "Quarter Video Graphics Array", featuring a 320 x 240 pixel grid.

Main applications

-- Mobile phones, mobile electronic devices etc. requiring a QVGA color display

Main features

-- See-through type achieving high brightness (150cd/m2)
-- Display contents not easily viewable from rear (for enhanced privacy)
-- Transmittance 40%

Main Specifications
-- Display area: 36.0 x 47.9 mm
-- Number of pixels: 240 x RGB x 320
-- Brightness: 150 cd/m2

* Current as of May 2011, TDK data.

About TDK Corporation

TDK Corporation (TSE: 6762; US: TTDKY) is a leading global electronics company based in Japan. It was established in 1935 to commercialize "ferrite," a key material in electronics and magnetics. TDK's current product line includes ferrite materials, electronic components and ICs, wireless computer networking products, magnetic heads for HDD, digital recording hardware and advanced digital recording media. For more information, please visit www.global.tdk.com.