Technical / Research - Page 71

Researchers from the University of Michigan led by Jinsang Kim developed new pure-organic phosphorescence materials made primarily of inexpensive carbon, oxygen, chlorine and bromine and are "easy" to synthesize. This is the first time anyone created an phosphorescence OLED that does not contain any metals. These materials could be used to create cheaper OLEDs (as OLEDs today still need a little bit of expensive metals in them). The new materials exhibit quantum yields of 55%.

The light in those OLEDs comes from oxygen and carbon molecules called "aromatic carbonyls". These materials form strong halogen bonds with halogens in the crystal to pack the molecules tightly. This arrangement suppresses vibration and heat energy losses as the excited electrons fall back to the ground state, leading to strong phosphorescence.

Polymertronics (a UK based company that offers customized experimentation OLED systems) announced their new flexible OLED science kit. These kits provide everything you need to make a working flexible OLED device and experiment with the chemistry, physical structure and the electronic parameters.

Polymertronics are now offering OLED-Info readers a £20 discount (that's about $32US) off their regular price of £290 - for both the flexible and the rigid (glass) spin-coated OLED science kits (and yes, they ship worldwide). To claim the discount simply mention OLED-Info when you place your order. And hurry up, this offer expires on the 15th of March!

Update: We have some new information about Samsung's AMOLED manufacturing process. It turns out that they plan to soon move to a laser-based method (LITI) from the currently-used shadow-mask method (FMM). This will allows them to achieve 300ppi or more...

Earlier today we posted about the Super AMOLED plus resolution - and now we got our answer. It turns out that my calculations about the pentile matrix were incorrect - it fact it uses 2 sub-pixels for each pixel while a 'real' RGB matrix (or Real-Stripe as Samsung calls it) uses 3 sub-pixels for each pixels - and here's your 50% increase. Here's Samsung's own image showing the difference:

It also turns out that a Real-Stripe matrix also takes up more space per pixel. This explains why a 4.3" display that uses Real-Stripe has the same resolution as a 4" with a penTile matrix. But this display should actually be clearer because of the added sub-pixels and better matrix design.

Update: We now got the answer to this little mystery, you can read it here.

Samsung's new Galaxy S2 phone has a Super AMOLED Plus display but something is strange about the resolution of this phone. It's a 4.3" panel with 800x480 resolution (WVGA). That's the same resolution found on the original Galaxy S that has a 4" Super-AMOLED. When Samsung announced the Super AMOLED Plus they said that it offers 50% more sub-pixels and offers over 300ppi.

The original Super AMOLED used Samsung's PenTile Matrix scheme (shown above on the right) - which uses a shared green pixel (RGBG). The Super AMOLED Plus displays uses a regular RGB matrix (shown above on the left). That means that you need more subpixels to show the same amount of pixels - indeed a pentile matrix uses 33% less pixels (for example a 4X4 RGB display will use 48 subpixels while a 4X4 RGBG pentile will use only 36 subpixels).

Back in May 2010 Dupont announced that they can print a a 50" OLED TV in under two minutes, using their new printable OLED materials and a custom-made printer from Dai Nippon Screen Manufacturing Co. Today we learned that Dupont estimates that their new OLEDs will be cheaper than LCDs - by about 40%! Regular OLEDs cost about twice as much  as LCDs to manufacture.

Dupont's new manufacturing process uses a continuous stream of ink (rather than droplets used in 'classic' inkjet design), and moves over a surface at rates of four to five meters per second while patterning a display. The spray-printer developed with Dai Nippon Screen works on Gen-4 substrates (730x920). Dupont is using a common structure for each pixel (red, green and blue) and isn't optimizing each pixel. This is less efficient, but results in faster throughput. 

Today we learned that Apple filed three OLED display related patents lately. The main patent (#20100321305) is about driving an OLED display structure that is integrated with a touch sensor (Samsung's Super-AMOLED is such a device, and we know that AUO is also developing an integreated multi-touch AMOLED). 

The second patent (#20100265187) discusses signal routing to an OLED structure that includes a touch actuated sensor configuration. The third patent (#20100265188) discusses the  integration of a touch actuated sensor configuration with an OLED structure.

Victrex and the Holst Centre presented progress in flexible substrate development based on Victrex's APTIV PEEK polymer film. The results are promising and Victrex decided to step into a full partnership with the Holst Centre. Victrex's material can withstand high processing temperatures in comparison with other thermoplastic materials, and can be used as a substrate for flexible and printed electronics such as OLED.

Specifically, enhancements were applied during the manufacturing process of APTIV PEEK film in order to fulfill the dimensional stability requirements of flexible substrates used in plastic electronics applications. In the study, the performance of the APTIV flexible electronics grade was compared to that of the standard extruded APTIV film along with other competing candidate films. Critical performance parameters were measured, such as the coefficient of thermal expansion, thermo mechanical properties and dimensional stability, mostly at up to 230ºC.

There are reports that Samsung developed a new technology that allows them to create larger AMOLED panels from their existing 5.5-Gen (1,300x1,500mm) production lines. Up until now Samsung had to cut the substrate to at least 3 parts and so the largest panel was 32". Now the company can make one 65" panel from each substrate - to make 65" OLED TV panels. This new technology will be implemented in Samsung's second 5.5-Gen line (scheduled for 2012).

Samsung's first 5.5-Gen line (A2 in Tangjeong) is scheduled to start producing AMOLEDs in 2Q 2011. This line will be used only for small panels (for mobile phones, cameras, etc.). The second line (A3, also in Tangjeong) is scheduled for 2012 and using the new technology this line can be used to make large panels - up to 65".

Israel's Yissum Research Development Company (the Technology Transfer Company of the Hebrew University of Jerusalem) and Korea's Vaxan Steel announced a new agreement to co-develop silver nanoparticles and silver-coated copper nanoparticles for conductive inks. These inks can be utilized in a variety of printing technologies, including inkjet printing, and can be used in applications such as OLEDs and RFID tags.

The new inks were invented by Professor Shlomo Magdassi, Dr. Alexander Kamyshny and Michael Grouchko from the Institute of Chemistry at the Hebrew University. Yissum granted Vaxan a license to commercialize the technology exclusively in Asia, excluding Israel and former Soviet Union countries, and will receive in return research fees and royalties from future sales. This is the first time a Korean company collaborates with an Israeli university.

Integrated Device Technology (IDT) developed the world's first single-layer multi-touch capacitive controller, called PureTouch. IDT explains that in normal multi-touch displays there are two or three layers of ITO - and they managed to use just a single layer in PureTouch. Having just one layer makes for cheaper touch screens, and also more efficient and bright ones. And it works for both LCD and AMOLED displays.

PureTouch display prototype

The only limitation of the new approach is that it only works well on small displays (up to 5" in size, and the maximum resolution is 1024x1024).