It’s been another exciting day at SID but I’m disappointed by the lack of OLED panels on the floor. After Samsung’s inspiring keynote session on OLEDs, I was looking forward to seeing two OLED panels in every booth and new recipes in every clean room. LG is displaying its 15-in. OLED and I did stumble on a 7-in. CMO AMOLED panel that is being discontinued. Rumor is both yields and demands were low.
On a more positive note, I had an interesting conversation with Janice Mahon of Universal Display and Florent Aubert of Novaled. I look forward to sharing their positive, but slightly contrasting views of where the OLED market is going. – Michael Moyer, Director of Engineering for I.E.E. in Van Nuys California.
Thursday, May 27, 2010
Merck's Involvement Suggests Longevity for Epaper
In the display industry, the name Merck (officially called EMD Chemicals here in the United States) is synonymous with liquid crystal chemistry. LCD researchers and manufacturers around the world rely on Merck to supply just the right LC mixture to produce their desired display effect. According to Merck’s Mark Goulding, the company may be about to expand its reach into materials for electronic paper. In an invited symposium talk delivered as part of Wednesday afternoon’s electronic paper session, Goulding showed his promising results in synthesizing a variety of brightly-colored particles and compounding them into electrophoretic suspensions.
Particle electrophoresis is the core technology behind EPD companies like E Ink and Sipix, which to date make up the lion’s share of e-paper products on the market. Today, these companies formulate their own materials using closely-guarded recipes. In his talk, Goulding suggested that Merck is evaluating whether to offer their own electrophoretic mixtures in the market, which could open up an opportunity for other display companies to experiment with this hot new technology. This probably won’t happen tomorrow, since Merck’s formulas will need more fine-tuning before rolling out. As an example, Goulding was not ready to comment on image stability, saying only that it is an area of active research at the moment; image stability is what allows e-readers to keep their image for long periods of time without requiring a refresh, and is critical to ultra-low-power operation of EPD’s. Nonetheless, this initiative by a major display materials supplier suggests that the e-paper market segment is here to stay, and its best days are still ahead of us. -- Robert Zehner, E Ink
*For additional information on Goulding's presentation, see Paul Drzaic's symposium rundown.
Particle electrophoresis is the core technology behind EPD companies like E Ink and Sipix, which to date make up the lion’s share of e-paper products on the market. Today, these companies formulate their own materials using closely-guarded recipes. In his talk, Goulding suggested that Merck is evaluating whether to offer their own electrophoretic mixtures in the market, which could open up an opportunity for other display companies to experiment with this hot new technology. This probably won’t happen tomorrow, since Merck’s formulas will need more fine-tuning before rolling out. As an example, Goulding was not ready to comment on image stability, saying only that it is an area of active research at the moment; image stability is what allows e-readers to keep their image for long periods of time without requiring a refresh, and is critical to ultra-low-power operation of EPD’s. Nonetheless, this initiative by a major display materials supplier suggests that the e-paper market segment is here to stay, and its best days are still ahead of us. -- Robert Zehner, E Ink
*For additional information on Goulding's presentation, see Paul Drzaic's symposium rundown.
Strong Showing at Display Week
Thur. May 27. Today is the last day of the exhibition at Display Week in Seattle, but the activities continue tomorrow with Symposium sessions on oxide TFTs, emerging display applications, digital signage, and much more.
By all accounts, attendance at this year's show is way up over last year's event, which took place in San Antonio during the economic downturn. The official figures aren't in yet, but the number is well above 5,000. Traffic on the exhibition floor is brisk, and there is simply a kind of buzz in the air. For more specifics, see analyst Chris Chinnock's Display Daily column on the show, "Display Week Opens with a Bang."
I was also excited to see that former PC Magazine Editor in Chief (now senior vice president for technology strategy at Ziff Brothers Investments) Michael Miller has been blogging the show, with some interesting comments about 3D in particular.
Here are two comments I heard by chance this week that sum up things nicely:
"Everything is happening with displays." -- overheard on the show floor, from a speaker who had apparently never been to SID before.
"It's a small show [compared to CES] but there is so much here!" -- overheard in the press room, from a long-time computer journalist.
--J. Donelan
By all accounts, attendance at this year's show is way up over last year's event, which took place in San Antonio during the economic downturn. The official figures aren't in yet, but the number is well above 5,000. Traffic on the exhibition floor is brisk, and there is simply a kind of buzz in the air. For more specifics, see analyst Chris Chinnock's Display Daily column on the show, "Display Week Opens with a Bang."
I was also excited to see that former PC Magazine Editor in Chief (now senior vice president for technology strategy at Ziff Brothers Investments) Michael Miller has been blogging the show, with some interesting comments about 3D in particular.
Here are two comments I heard by chance this week that sum up things nicely:
"Everything is happening with displays." -- overheard on the show floor, from a speaker who had apparently never been to SID before.
"It's a small show [compared to CES] but there is so much here!" -- overheard in the press room, from a long-time computer journalist.
--J. Donelan
Elo Continues to Innovate
Elo TouchSystems (booth 1207) is demonstrating at least two interesting touch-related innovations. The first is a result of Elo’s acquisition of Sensitive Object in January of this year. The demo of one of Sensitive Object’s capabilities consists of a large sheet of acrylic with two acoustic sensors clamped to the sheet in arbitrary locations, as shown in the photo above. The sensors are connected to a small control box. Four arbitrary spots are selected on the acrylic sheet. Each spot is tapped rapidly with a finger until the control box sounds a long tone. the four spots are “calibrated”, only those four spots respond to touch; touches anywhere else on the acrylic sheet are ignored. This is a simple illustration of how Sensitive Object’s “ReverSys” technology uses stored waveforms of acoustic signatures to identify touches at a specific location. technology isn’t restricted to use on flat surfaces; it also works on multi-dimensional objects.
The second demo is of a surface acoustic wave (SAW) monitor with zero-bezel (edge-to-edge glass) design. SAW normally has a set of reflectors around the border of the screen that prevents a bezel-less configuration. Elo has figured out how to locate the reflectors (and the piezo transducers) on the back of the glass, leaving the front of the glass as an entirely flat surface. The trick is in shaping the edge of the glass so that the acoustic waves are guided from the back of the glass around to the top surface. The current demonstration product is single-touch; Elo indicated that dual-touch might be possible in the future. --Geoff Walker, NextWindow
Wednesday, May 26, 2010
An Almost-live Look at Today's E-paper Symposium Sessions
Wed, May 26. Along with Dr. Rob Zehner of E Ink, I cochaired Electronic Paper II in the SID Symposium at Display Week today. I also wrote about the talks as they progressed, including my thoughts and notes, to give you a flavor of the progression of a symposium session. So I did double duty as chair and blogger.
Paper 1. First up was Mark Goulding of Merck Chemicals in the UK, discussing Merck's work on dyed polymeric microparticles for electronic paper displays. Rather than using inorganic pigments (which is typical for electrophoretic (EPD) displays such as those used by E Ink), Merck is developing polymeric particles that can serve as pigments in these displays. Colored EPD displays continue to be a challenge, and are not common in today’s marketplace.
Most color EPDs use a black and white shutter, with a color filter overlay. Goulding notes that this approach is limited in performance and may be high in cost. Rather than additive color (RGB color filter), Merck is developing subtractive color modes, similar to those used in newspapers. Stacked subtractive color EPDs should provide better color saturation and performance than single layer additive color filter approaches.
Synthetic polymer particles can be controlled in a wide variety of optical and physical parameters. For example, the zeta potential (the charge on the particle) can be controlled for both positive and negative charges, and for different colors. Uniform particle size can be produced, as a specified size with a narrow size distribution. Uniform particle sizes ranging from 220 nm to 850 nm in diameter were shown in a micrograph. Dye concentration within particles, and particle volume fraction within the EPD, can both be accurately controlled. Density and refractive index can also be dialed in, which affects transport and light scattering, respectively.
Question: How would you actually fill a cell with multiple different colors?
Answer: that’s a current area of interest.
Question : are the particles bistable? Answer: No results to share.
Overall, a good start on an interesting way to push the color EPD forward. Next steps will be to continue to improve performance, and to build some real devices. Color EPD continues to be a challenge, so success here could be quite important to the epaper field.
Paper 2. T. Yoshihara of Fujitsu presented a paper on orientation control of cholesteric LC for epaper. Fujitsu is pushing hard on stacked cholesteric liquid displays for epaper applications. Stacked layers can in principle show good brightness and saturation, though past examples of stacked color have not been particularly bright. This paper was aimed at improving contrast ratio and brightness, through improved orientation control over the cholesteric LCs. Cholesteric panels don’t require an active matrix and can be bistable, both desirable properties.
An alignment layer with rubbing is the approach. The rubbing pattern and rubbing strength are the key elements here. For the rubbing pattern, cross-rubbing (perpendicular on opposing surfaces) provided a wide set of viewing angles. Rubbing density (strength) also was critical – it’s possible to rub too weakly, or too strongly. So, an intermediate rubbing strength is optimal.
The pretilt angle (the angle of the liquid crystal director at the surface) was also examined – this property can be controlled by choice of alignment layer. Both reflectance (brightness) and contrast were considered. A pretilt angle of 10 degrees appeared to be optimal. This material also showed the widest process window in terms of fabrication.
Reflectance of up to 40% was achieved. Fujitsu has improved the appearance of its cholesteric devices (such as the Flepia information device and electronic card holder). To my eye, the photographs did show marked improvement over past efforts by this team.
Question: why is cross rubbing the best? Any physical explanation? No particular insights available from the author.
Paper 3. J.-Y. Kim of Samsung Electronics described the company's 4.8-in. active matrix PDLC display, using printed organic field effect transistors (OFETs).
SAIT (Samsung Advanced Institute of Technology) is performing R&D on printed transistors, due to the interest in flexible displays. Strong market demand for epaper makes this an important area for development. Color, video, and low cost are key areas for focus.
Notes:
-A maskless TFT fab process can reduce cost by 50%, and avoiding vacuum processes reduces costs by 30%.
-Polymer dispersed liquid crystals switch between scattering and transparent state, and don’t require polarizers. They’re good for reflective and for flexible displays.
-For flexible epaper, printed OFETs have low mobility. PDLCs have had low voltage holding ratio, and the color filter layer disposition is complex.
-SAIT is using polymer semiconductors that are printable, and are compatible with flexible semiconductors.
-Newly developed polymer semiconductors – quaterthiophene and bithiazole units with mobility up to 0.5 cm2/VS. Stability data is not available - they’re filing patents!
SAIT has worked on printed OFETs since 2006, showing steady progress. In 2009, it achieved 4.8-in. on plastic, 400x240 pixels @ 100 dpi. Now using inkjet process for color epaper.
UV irradiation is complicated with color filters, since filter affects UV intensity in different colors. Exposure from the backplane side requires high aperture ratio, which complicates pixel design for good optical performance.
Color filter on array – put directly onto the TFT electrode – was described. The PDLC is built on *top* of the color filter/TFT layer – very clever. UV intensity is now extremely uniform and intense. Pixel design with high aperture ratio is achieved.
A seven step process was shown for cell fabrication. First steps were using SiOx gate dielectric over the gate metal. The semiconductor is printed. Mobility is 0.15 cm2/Vs, W/L 200 um/10 um
Gage and data line widths are 20 micron. 80 ppi display was shown – 18% reflect, 4:1 contrast.
In the Q&A, it was stated that a dyed PDLC was used as the display system. UV curing of dyed PDLC has traditionally been very difficult – how did the authors solve? Wait for the next paper!
Paper 4. Research of PDLC structures for flexible displays was presented by G.H. Lee of Samsung Electronics. There are several different PDLC modes, and this paper reviewed their characteristics for color epaper. This was a companion paper for paper 3, focusing on the PDLC portion of the display.
Notes:
-PDLC great for gray scale and video response.
-Normal PDLC – scattering and transparent state. High reflectance requires
-Color PDLC with color filter, shows low reflectance (9%), but good color and contrast. How to improve?
-Dichroic PDLC can show both strong absorbance and scattering, and weak absorbance and clarity. Good contrast and high reflectance.
-Very high UV exposure is required for dye containing PDLC, since the dye absorbs UV light. The color filter on TFT approach (COA) enables high power UV exposure.
-PEN substrate for flexible substrate.
-8:1 contrast, 16% reflectance, 30 Hz driving, 4.8 inch, QVGA.
-Advanced mode: make each pixel with its own dichroic color (RGB or CMY) PDLC, without use of a color filter. RBG can’t generate a good black state. CMY system provides a brighter image with black dye PDLC.
-Black dye with color filter
-RGB- 12-16%
-CMY – 16-22%, with contrast ratio over 5:1.
-22% is very high for reflective color, using black dye with CMY color filter. Apparently there is a ten minute UV cure time, which is a little long.
Overall, this is a very promising approach for a color, video-capable epaper display.
--Paul Drzaic, Drzaic Consulting Services and Past-President SID.
Paper 1. First up was Mark Goulding of Merck Chemicals in the UK, discussing Merck's work on dyed polymeric microparticles for electronic paper displays. Rather than using inorganic pigments (which is typical for electrophoretic (EPD) displays such as those used by E Ink), Merck is developing polymeric particles that can serve as pigments in these displays. Colored EPD displays continue to be a challenge, and are not common in today’s marketplace.
Most color EPDs use a black and white shutter, with a color filter overlay. Goulding notes that this approach is limited in performance and may be high in cost. Rather than additive color (RGB color filter), Merck is developing subtractive color modes, similar to those used in newspapers. Stacked subtractive color EPDs should provide better color saturation and performance than single layer additive color filter approaches.
Synthetic polymer particles can be controlled in a wide variety of optical and physical parameters. For example, the zeta potential (the charge on the particle) can be controlled for both positive and negative charges, and for different colors. Uniform particle size can be produced, as a specified size with a narrow size distribution. Uniform particle sizes ranging from 220 nm to 850 nm in diameter were shown in a micrograph. Dye concentration within particles, and particle volume fraction within the EPD, can both be accurately controlled. Density and refractive index can also be dialed in, which affects transport and light scattering, respectively.
Question: How would you actually fill a cell with multiple different colors?
Answer: that’s a current area of interest.
Question : are the particles bistable? Answer: No results to share.
Overall, a good start on an interesting way to push the color EPD forward. Next steps will be to continue to improve performance, and to build some real devices. Color EPD continues to be a challenge, so success here could be quite important to the epaper field.
Paper 2. T. Yoshihara of Fujitsu presented a paper on orientation control of cholesteric LC for epaper. Fujitsu is pushing hard on stacked cholesteric liquid displays for epaper applications. Stacked layers can in principle show good brightness and saturation, though past examples of stacked color have not been particularly bright. This paper was aimed at improving contrast ratio and brightness, through improved orientation control over the cholesteric LCs. Cholesteric panels don’t require an active matrix and can be bistable, both desirable properties.
An alignment layer with rubbing is the approach. The rubbing pattern and rubbing strength are the key elements here. For the rubbing pattern, cross-rubbing (perpendicular on opposing surfaces) provided a wide set of viewing angles. Rubbing density (strength) also was critical – it’s possible to rub too weakly, or too strongly. So, an intermediate rubbing strength is optimal.
The pretilt angle (the angle of the liquid crystal director at the surface) was also examined – this property can be controlled by choice of alignment layer. Both reflectance (brightness) and contrast were considered. A pretilt angle of 10 degrees appeared to be optimal. This material also showed the widest process window in terms of fabrication.
Reflectance of up to 40% was achieved. Fujitsu has improved the appearance of its cholesteric devices (such as the Flepia information device and electronic card holder). To my eye, the photographs did show marked improvement over past efforts by this team.
Question: why is cross rubbing the best? Any physical explanation? No particular insights available from the author.
Paper 3. J.-Y. Kim of Samsung Electronics described the company's 4.8-in. active matrix PDLC display, using printed organic field effect transistors (OFETs).
SAIT (Samsung Advanced Institute of Technology) is performing R&D on printed transistors, due to the interest in flexible displays. Strong market demand for epaper makes this an important area for development. Color, video, and low cost are key areas for focus.
Notes:
-A maskless TFT fab process can reduce cost by 50%, and avoiding vacuum processes reduces costs by 30%.
-Polymer dispersed liquid crystals switch between scattering and transparent state, and don’t require polarizers. They’re good for reflective and for flexible displays.
-For flexible epaper, printed OFETs have low mobility. PDLCs have had low voltage holding ratio, and the color filter layer disposition is complex.
-SAIT is using polymer semiconductors that are printable, and are compatible with flexible semiconductors.
-Newly developed polymer semiconductors – quaterthiophene and bithiazole units with mobility up to 0.5 cm2/VS. Stability data is not available - they’re filing patents!
SAIT has worked on printed OFETs since 2006, showing steady progress. In 2009, it achieved 4.8-in. on plastic, 400x240 pixels @ 100 dpi. Now using inkjet process for color epaper.
UV irradiation is complicated with color filters, since filter affects UV intensity in different colors. Exposure from the backplane side requires high aperture ratio, which complicates pixel design for good optical performance.
Color filter on array – put directly onto the TFT electrode – was described. The PDLC is built on *top* of the color filter/TFT layer – very clever. UV intensity is now extremely uniform and intense. Pixel design with high aperture ratio is achieved.
A seven step process was shown for cell fabrication. First steps were using SiOx gate dielectric over the gate metal. The semiconductor is printed. Mobility is 0.15 cm2/Vs, W/L 200 um/10 um
Gage and data line widths are 20 micron. 80 ppi display was shown – 18% reflect, 4:1 contrast.
In the Q&A, it was stated that a dyed PDLC was used as the display system. UV curing of dyed PDLC has traditionally been very difficult – how did the authors solve? Wait for the next paper!
Paper 4. Research of PDLC structures for flexible displays was presented by G.H. Lee of Samsung Electronics. There are several different PDLC modes, and this paper reviewed their characteristics for color epaper. This was a companion paper for paper 3, focusing on the PDLC portion of the display.
Notes:
-PDLC great for gray scale and video response.
-Normal PDLC – scattering and transparent state. High reflectance requires
-Color PDLC with color filter, shows low reflectance (9%), but good color and contrast. How to improve?
-Dichroic PDLC can show both strong absorbance and scattering, and weak absorbance and clarity. Good contrast and high reflectance.
-Very high UV exposure is required for dye containing PDLC, since the dye absorbs UV light. The color filter on TFT approach (COA) enables high power UV exposure.
-PEN substrate for flexible substrate.
-8:1 contrast, 16% reflectance, 30 Hz driving, 4.8 inch, QVGA.
-Advanced mode: make each pixel with its own dichroic color (RGB or CMY) PDLC, without use of a color filter. RBG can’t generate a good black state. CMY system provides a brighter image with black dye PDLC.
-Black dye with color filter
-RGB- 12-16%
-CMY – 16-22%, with contrast ratio over 5:1.
-22% is very high for reflective color, using black dye with CMY color filter. Apparently there is a ten minute UV cure time, which is a little long.
Overall, this is a very promising approach for a color, video-capable epaper display.
--Paul Drzaic, Drzaic Consulting Services and Past-President SID.
LEDs vs. CCFLs
If you follow displays at all, you know that LEDs are taking over from CCFLs when it comes to backlighting. But there's still life in the old cold cathode fluorescent lamp yet. For one, many industrial and medical clients must have every piece of equipment they use certified, and changing the backlighting of a display module would very likely necessitate recertification. Consequently, a number of these companies are sticking with their CCFLs for the time being.
Second, there are shortages in some areas of the LED market, notes Scott Barney, director of sales and marketing for Endicott Research Group, which makes both LED and CCFL backlighting systems for major panel manufacturers. Some of those manufacturers are waiting for LEDs in order to roll out their next LED-backlit products, he explains.
Still, for the most part, LEDs are definitely the backlighting technology of choice for LCDs these days. And not all LEDs are facing shortages, notes Brett Shriver, director of sales for Global Lighting Technologies. It depends on the type and the package, he explains. -- J. Donelan
Second, there are shortages in some areas of the LED market, notes Scott Barney, director of sales and marketing for Endicott Research Group, which makes both LED and CCFL backlighting systems for major panel manufacturers. Some of those manufacturers are waiting for LEDs in order to roll out their next LED-backlit products, he explains.
Still, for the most part, LEDs are definitely the backlighting technology of choice for LCDs these days. And not all LEDs are facing shortages, notes Brett Shriver, director of sales for Global Lighting Technologies. It depends on the type and the package, he explains. -- J. Donelan
3D Eye Candy
Covering the SID exhibit floor is a nearly impossible task, for a couple reasons. There is just too much for one person to take in, and for the demonstrations you do see, selecting the ones to write about is difficult. So, for this entry, I’ll note two stunning examples of display technology that caught my eye, and certainly meet the definition of “eye candy” – a delicious, visual delight.
Walking onto the show floor, it doesn’t take long to see several crowds clustered around some hot offerings. Fighting through the peopole around the LG Display booth and grabbing a pair of glasses, I enjoyed the demonstration of the world’s largest 3D display. Built using LG’s IPS liquid-crystal technology and measuring a whopping 84inches, this display sports UHD resolution with 3840 x 2160 pixels. While the display can render either 2D or 3D images, the demonstration video showing 3D animation was a delight to watch. It was easy to imagine a future where I could sit down in a comfortable chair and enjoy the 3D content from the comfort of my own home on this giant screen. LG Display also showed several other 3D systems in smaller sizes that will be the basis of the next generation of 3D–ready television products.
Wandering a bit further into the exhibit, Panasonic also had an impressive set of 3D hardware. Based on its blazing-fast plasma technology, Panasonic's 65-inch 3D televisions featured full HD (1920 x 1080) for each eye. I was told that special phosphors had been developed for these displays, reducing the persistence time of the phosphor by 1/3 compared to the previous technology. These short persistence phosphors improve the response time to provide a super-crisp image. These systems were both Blu-Ray and Direct TV compatible. Movie clips and sport content were a pleasure to watch in 3D.
It was also fun to watch myself in 3D in real time--Panasonic demonstrated a Full HD professional 3D video camera, aimed at the show floor. I could duplicate many of the tricks that I see in 3D movies in real time, probably drawing too much attention to myself from passers-by. With this technology, it’s easy to imagine a time when reporters and other professionals routinely capture and transmit 3D content, to be broadcast to 3D-capable home televisions. Once this sort of capability becomes routine, consumer-based systems are likely to follow.
All in all, the 3D capabilities shown by LG Display, Panasonic, and a number of other companies are quite impressive. Making sure that future television purchases are 3D-ready will increasingly become a wise choice for consumers.
--Paul Drzaic, Drzaic Consulting Services and Past-President, SID
Walking onto the show floor, it doesn’t take long to see several crowds clustered around some hot offerings. Fighting through the peopole around the LG Display booth and grabbing a pair of glasses, I enjoyed the demonstration of the world’s largest 3D display. Built using LG’s IPS liquid-crystal technology and measuring a whopping 84inches, this display sports UHD resolution with 3840 x 2160 pixels. While the display can render either 2D or 3D images, the demonstration video showing 3D animation was a delight to watch. It was easy to imagine a future where I could sit down in a comfortable chair and enjoy the 3D content from the comfort of my own home on this giant screen. LG Display also showed several other 3D systems in smaller sizes that will be the basis of the next generation of 3D–ready television products.
Wandering a bit further into the exhibit, Panasonic also had an impressive set of 3D hardware. Based on its blazing-fast plasma technology, Panasonic's 65-inch 3D televisions featured full HD (1920 x 1080) for each eye. I was told that special phosphors had been developed for these displays, reducing the persistence time of the phosphor by 1/3 compared to the previous technology. These short persistence phosphors improve the response time to provide a super-crisp image. These systems were both Blu-Ray and Direct TV compatible. Movie clips and sport content were a pleasure to watch in 3D.
It was also fun to watch myself in 3D in real time--Panasonic demonstrated a Full HD professional 3D video camera, aimed at the show floor. I could duplicate many of the tricks that I see in 3D movies in real time, probably drawing too much attention to myself from passers-by. With this technology, it’s easy to imagine a time when reporters and other professionals routinely capture and transmit 3D content, to be broadcast to 3D-capable home televisions. Once this sort of capability becomes routine, consumer-based systems are likely to follow.
All in all, the 3D capabilities shown by LG Display, Panasonic, and a number of other companies are quite impressive. Making sure that future television purchases are 3D-ready will increasingly become a wise choice for consumers.
--Paul Drzaic, Drzaic Consulting Services and Past-President, SID
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