I-Zone Turns Seven
Five Innovation Zone exhibitors received recognition for their emerging, best-in-class display technology at Display Week 2018.
by Steve Sechrist
FROM its inception seven years ago, the Innovation Zone (I-Zone), the exclusive, peer-reviewed exhibition area at Display Week, was meant to augment the research/academic and commercial offerings of the event with horizon technology and “what-if” possibilities to spur imagination, nurture communications, and ultimately lead to developments that would broaden display technology. When you visit the I-Zone, you are guaranteed to see technology that has not been shown elsewhere, and early-stage technology that will form the basis for commercial products in years to come.
Just one example of such a technology is PolarScreens, founded in 2003 and making its Display Week debut in 2015. Based on eye-tracking technology, the company’s “steerable backlight system” directed the LCD backlight into the eyes of the user being tracked. Its most recent iteration is in the new Kyocera autostereo 3D head-up display (HUD) prototypes that are scheduled for production by 2020.
The 2018 I-Zone was a record breaker. It has doubled in size from the first year, growing to almost 50 booths. This year also marked the first time the I-Zone has been split into two different sections on the exhibition floor, making it easier to explore all the cutting-edge technology. This was also the first year that the I-Zone Committee honored a total of five I-Zone participants for outstanding technology: Hong Kong University of Science and Technology for Best Prototype; and Dimenco, Hong Kong Jade Bird Display, PlayNitride, and XTPL SA as honorees.
Probably the most talked-about technology at Display Week 2018, microLED, was represented in the I-Zone by several exhibits, as described below. Other leading-edge technologies shown in the I-Zone included light-field displays, transparent displays, low-cost printed color displays, and chip-on-display technologies. There was even an exhibit on nano-based electrode printing for high-value device repair.
Hong Kong University of Science and Technology
This year’s “Best Prototype” winner was Hong Kong University of Science and Technology, which developed a 250-pixel-per-inch (ppi) active-matrix field-sequential-color (FSC) display panel based on electrically suppressed helix ferroelectric liquid-crystal (ESHFLC) technology.
The significance of this new, very-fast field-sequential color display is that it that could potentially replace in-plane switching (IPS) or fringe-field switching (FFS) modulation for the portable/mobile market. The high-resolution FSC-ESHFLC might also find use in emerging virtual reality displays.
In the I-Zone, the group from the university (Fig. 1) demonstrated the 3-in. color display (Fig. 2) operating on an ultra-fast response time (~10 µs) at very low voltage (6.67V/µm) that enabled a 60-Hz frame rate with a 360-Hz FLC drive frequency.
Fig. 1: The team from Hong Kong University of Science and Technology stands in the I-Zone with its award-winning display technology. Pictured from left to right: Abhishek Kumar Srivastava, Swadesh Gupta, Alex Cheung, Liangyu Shi, Vladimir Chigrinov, and Chenxiang Zhao, all of Hong Kong University. Photo: Steve Sechrist
Fig. 2: Hong Kong University of Science and Technology’s 3-in. diagonal, 250-ppi active-matrix field-sequential color display featured an ultra-fast response time of ~10 µs. Photo: Steve Sechrist
The prototype included a 3T1C pixel circuit that was designed to convert the analog drive signal to run in a pulse-width modulation mode. This was achieved on low-temperature polysilicon (LTPS) thin-film transistor (TFT) panels, resulting in an active-matrix FSC ESHFLC integrated display system. It is important to note that this is an LCD that is capable of switching gray states fast enough to enable field sequential color imaging, with a highly improved gray-scale performance.
The research group says its “anchoring energy” is comparable to but less than the elastic energy of the helix of FLC. The team also confined the FLC to the ESHFLC mode, where it is mechanically stable and free of chevron defects. It also offers a high contrast ratio over conventional surface-stabilized FLC. When combining the FLC fast-response (around 10 μs under 6.66V/μm), low-driving voltage into a field sequential system, researchers can achieve triple the current resolution for a wide variety of applications, including emerging virtual reality and next- generation liquid-crystal displays. In a video interview with I-Zone Chair Harit Doshi, the research team said that the next step for the technology was to find some suitable applications (and interested partners.)
Benefits outlined by the group include:
• No color filters • In-plane switching (IPS) with reduced color shift compared to traditional IPS LCD • Analog gray scale • 3X high light efficiency panel • 3X resolution (360 gate × 640 column) without any sub-pixels (see above) • Wide color gamut
The Hong Kong University team also authored a distinguished student paper at Display Week, “Active-Matrix Field-Sequential Color Electrically Suppressed Helix Ferroelectric Liquid Crystal for High Resolution Displays.”
The four companies that received 2018 honoree designations in the I-Zone are:
Dimenco
Dimenco, founded in 2010 by former Philips engineers, showed its newest LC alignment layer for switchable lenses in the I-Zone (Fig. 3). Dimenco’s glasses-free 2D-3D switchable displays are made by applying lenticular lenses on top of an LCD. The lenses are turned on and off by switching the orientation of the liquid crystals. This lenticular lens technology is not new. What is new is that Dimenco has replaced the conventional polyimide alignment layer on the lenticular lens with nanogrooves, which improves the alignment of the liquid crystals. In this way, the polyimide layer can be eliminated, which simplifies the production process and improves the optical quality of the lens, while reducing cross-talk “significantly,” according to spokesperson Maartin Tobias of Dimenco.
It’s reasonable to question the significance of a glasses-free 3D display in the age of VR, AR, and 8K devices, but in fact 3D continues to be a niche display area, with many commercial and medical applications.
Fig. 3: Dimenco showed its newest glasses-free switchable 2D-3D panel in the I-Zone. Photo: Steve Sechrist
Hong Kong Beida Jade Bird Display
Hong Kong Beida Jade Bird Display (JBD) showed an active-matrix microLED in a chip format with 5K pixels per inch and 1 million cd/m2 of luminance (green rated at 500 lu, red rated at 300 lu, blue at 250 lu). The microLED on integrated circuit (IC) panel specs include 640 resolution, 20-µm pixel pitch, RGB single color, and 256 gray levels, at an operating voltage of 5.3 V with typical power consumption of 6 W at 60-Hz refresh.
This microLED was based on monochromatic red, green, and blue microdisplay panels. JBD also showed application demos using the panels (Fig. 4). These included a portable projector with ultra-high-luminance microLED microdisplays in excess of 3 million cd/m2 (for the green color), and AR goggles using an ultra-high resolution microLED microdisplay (with a pixel density higher than 5K ppi.)
In an SID video interview conducted at Display Week, the company principals said they believed that the technology would be ready for full-color small-area projectors as early as 2019. Other possible applications include head-up displays for vehicles. Jade Bird also relayed that it was recently contacted by a potential customer interested in using its technology for a military application.
Fig. 4: JBD showed its microLED integrated into a near-to-eye device in the I-Zone. Photo: Steve Sechrist
PlayNitride, Inc.
PlayNitride, Inc., created a transparent display using a unique process to transfer its RGB microLEDs onto the backplane substrate. The group showed a 3.12-in. diagonal 256 × 256 resolution, transparent, full-color RGB microLED display with a luminance of more than 800 cd/m2 and a wide color gamut (Fig. 5).
The pixel size was 0.219 mm, and Play-Nitride claimed this represented the equivalent of a section of a 76-in. diagonal 8K display. The mass-transfer process is characterized as 8 shots per color and 24 shots per panel, with microLED quantity at 262K chips/color and 786K chips per panel.
Fig. 5: PlayNitride’s transparent microLED display was 3.12 inches diagonal, with a luminance of more than 800 cd/m2. Photo: Steve Sechrist
XTPL SA
XTPL SA has developed technology that enables ultraprecise printing of nanomaterials. According to the company, the XTPL solution allows users to repair interrupted thin conductive lines in the production stage, without complicated, slow, and expensive vacuum processes. To get there, XTPL created an innovative process for printing electrodes that are several hundred times thinner than a human hair, with conductive lines thinner than 100 nm (Fig. 6).
Initial use is for corrective procedures in high-cost manufacturing of displays. XTPL created a unique printing head and dedicated nano-inks for repairing defects in electrical connections at micrometric and nanometric scale (conductive lines from 100 nm to 3 µm). There is also an optical detection system that is already in commercial use to provide a full technological solution the company can implement on production lines. Target markets include solar cells, LCD/OLED panels, PCBs, multichip modules (MCMs), and integrated circuits.
Fig. 6: XTPL’s innovative process prints electrodes that are several hundred times thinner than a human hair (< 100 nm to 3 µm). Source: XTPL SA
Additional I-Zone Displays of Interest
rdot AB showed a low-cost, energy-efficient, printed electrochromic color display.
The company’s roots are in the National Institute of Technology at Sendai College. The group is working on developing and commercializing an ultra-low-cost and energy-efficient reflective electrochromic color display.
In the I-Zone, the group showed a single-substrate, surface-mounted chip component on a roll-to-roll display. The roll to roll enables large-volume production, with benefits that include energy efficiency (1 mj/cm2 or millijoule 1/10,000 of a joule per sq. cm) per switch, ultra-low cost due to mature manufacturing processes, and a flexible substrate with a less-than-5-mm bend radius. The rdot technology also offers a static display memory that lasts up to 60 minutes without power.
Manufacturing goals for the printable electrochromic display include small and large formats and multiple shapes and forms. According to rdot AB, prototypes, including segmented displays, are close to market-ready – but no one there will say just how close… at least not yet.
FoVI3D showed its integral imaging type light-field display the company describes as “a glasses-free, 90 × 90-mm, full-parallax, horizontal light-field display with a 90° projection frustum.”
It is important to note there were two displays – one that targeted spatial resolution and one focused on angular resolution. The latter (a smaller 3.5-in. display) boosts the field of view (FOV) and depth volume at the cost of resolution. This smaller device achieved a 90-degree FOV with a 1-mm hogel diameter. The group built a 90-squared hogel display that created a 9 cm-cubed active light-field volume with a 110 × 110 vph (views per hogel).
Alternatively, a reduced field of view resulted in a roughly 5-in. tall display with a 60-degree FOV, a 0.5-mm hogel diameter, and a 180 squared hogel display with a 50 × 50 vph. The primary difference was the microlens array size, which determined the size of the hogel diameter (1 mm vs. 0.5 mm).
FoVI3D said it was going for a “natural visualization experience.” Optical elements were used to project light from a spatial light modulator (SLM) toward the viewer. FoVI3D said it is critical for the optical design to be both correct and optimized, so the company is focusing on both calibration and developing its own set of agnostic APIs (application program interfaces) to enable the projections.
Information College of Nankai University, Tianjin, showed a patented technology using what the developers call “non-paraxial axis optics” to deliver a 3D experience without passive polarizing glasses, or the active LC shuttering more commonly used. This personal stereoscopic cinema device was shown earlier this year at the International Conference on Display Technology (ICDT) in Guangzhou before coming to the 2018 I-Zone. The system shown at the exhibition used a dual screen with an impressive resolution of 2,560 × 1,440.
I-Zone Exhibits Hold Promise for the Future
This year’s I-Zone did not disappoint, with an extended number of new and emerging technologies on display. There were some game-changing prototypes, devices, and applications; new updates on 3D passive displays, and even an optical 3D solution. Those companies that succeed can say they started out in a humble I-Zone booth as part of SID’s Display Week. So hats off to the hard working I-Zone committee and also E Ink (itself a startup not that many years ago), which has sponsored the I-Zone since its inception.
Steve Sechrist is a display analyst and frequent contributor to Information Display magazine. He can be reached at esechrist@gmail.com.