Next generation microLED display technology is still evolving. A glimpse of that was seen at DisplayWeek 2020. While some suppliers showcased microLED display prototypes virtually, others in the supply chain presented about materials, process and technology innovations that will help the commercialization of products.
MicroLED provides the best features of LCD and OLED display and has the potential to outperform both technologies. It is still not in volume production due to manufacturing, production, scaling and yield issues. Technology innovations are critical in enabling cost reductions and volume productions so that microLED can compete effectively with OLED and LCD in future.

MicroLED Display: Prototypes Shown Virtually
Many suppliers including AUO, Playnitride, Tianma, ITRI, Jade Bird Display and others showcased virtual prototypes of products focusing on a variety of applications.

AUO
AUO focused on auto applications and showed its LTPS TFT driven 12.1-inch (169 PPI) microLED display with glass backplane and its latest 9.4-inch (228 PPI) flexible display with PI (Polyimide) co-developed with Playnitride. The automotive application is considered to be ideal for mid-sized microLED display because of its higher brightness, reliability, and ability to operate in very wide temperature range.

Tianma
Tianma showcased a 7.56-inch (114 PPI), >600 nits flexible and a 5.04inch (114 PPI), 600nits LTPS TFT microLED display for automotive applications. It also had 5.84" MicroLED+E-Paper display for Ebook applications.

Playnitride
Playnitride demonstrated the advantages of microLED display for transparent and auto display. It showed its 7.56inch transparent display as well as other displays co-developed with AUO and Tianma. Its transparent display has 60% transparency. According to industry sources microLED has the potential to achieve 80% maximum transparency, which is higher than OLED.

ITRI
ITRI showed a flexible foldable and transparent microLED. Its curved design makes it suitable for various types of consumer applications 

Jade Bird Display
Jade Bird Display showed a 0.31-inch monochrome 720P (5000 DPI),  a 0.22-inch 1080P (10K DPI), and a 0.13-inch VGA (6000DPI), microLED for microdisplays with Si-IC backplanes focused on AR/VR.

MicroLED Display: Technology Innovations Presented
Self-emitting microLED displays are simple in structure compared to OLED and LCDs but have a complex manufacturing process. MicroLED displays integrations can use a pick and place process where chips are transferred from epiwafers or carriers to the display backplane (LTPS or oxide on a glass or flexible PI substrate). It can also use a monolithic integration process which involves microLED arrays and backplane hybridization. Display integration, production and manufacturing process are still evolving to improve throughput and reduce yield issues. Manufacturing and yield problems can become an issue in several parts of the process such as epitaxy, chip making, mass transfer, bonding, driving technology, backplane, inspection and repair. At DisplayWeek many companies presented papers focused on improving transfer, inspections and manufacturing technology for microLED. iBeam, VueReal, InZiv and Compound Photonics presented at the Business Conference.

iBeam: GaN on Flexible Metal Technology
Instead of producing GaN LEDs on rigid 6-inch sapphire wafer at a high cost, iBeam has devised a new solution of fabricating LEDs directly on polycrystalline flexible metal foil (without transfer). Large area metal foil can replace sapphire wafers as a substrate for LEDs.
This way GaN production can scale up to Roll-to-Roll (R2R) manufacturing. This process can enable large scales monolithic integration of LEDs. In this scalable process a single-crystal-like layer is artificially created on polycrystalline or amorphous substrate (can be used also with glass or ceramic).
Their next step is to achieve milestone for low cost manufacturing process. According to the company, yield and reliability can improve greatly in their process compared to mass transfer approaches. Quantum Dot down-conversion for red and green color can also exceed DCI-P3 color gamut. The presentation said that the cost of display scales with area, not with the number of pixels, unlike other microLED approaches. So a 4K or 8K resolution cost will be same as 1K-resolution display. Also the R2R factory manufacturing cost can be lower ($100M) compared to a wafer ($1B) or LCD fab ($2B).  The company said a process where low cost GaN deposition is combined with R2R production, can lead to substantial cost reduction (>20x reduction in Epi cost). This will enable microLED displays to be more cost competitive with OLED in future. Samsung Ventures has invested in the company. For more see iBeam Gets Help to Be Disruptive from a Tech Giant.

VueReal: Micro-Solid Printing
VueReal presented information about their Micro-Solid printing technology which is said to solve limitation to yield, throughput, cost and performance. In the VueReal process MicroLEDs are printed directly from a cartridge to a display substrate selectively. This can reduce repair cost by 10 times. It has multi cartridge transfer (>100 cartridges at once) and multi color cartridge (RGB cartridge) can be used. As only one transfer is needed to populate red, green and blue, it can improve throughput by more than 3 times. It is also compatible with <5um vertical LEDs, compatible for TV, smartphone, watch, auto and other applications, as well as compatible with existing tool and with lateral, vertical and flip chips. Fully inspected cartridge can be use to identify defects, bin for performance, and protect microLEDs during printing, thus improving yields.
According to VuReal, their MicroSolid printing has competitive advantages over pick and place processes, especially for smartphone, tablet, IT, auto and TV use. Using their patented continuous pixelation solution they have demonstrated a 30K PPI LED array. The company is planning to start sales in 2021 - their solution of integrating an inspection cartridge with existing transfer tools can reduce repair cost and increase throughput. Then in 2023 the company is planning to sell their MicroSolid printer for high volume application markets such as TV, smartphone, IT and others. Their printing solution can be used for original mother glasses for those applications offering high yield and throughput. It can also be used for <10 micron microLEDs which will be critical for cost competitiveness with LCD and OLED.

InZiv: High Resolution Inspection Tools
InZiv provides high-resolution inspection tools for microLED, OLED and QLED. It helps in nano-scale optical, spectral, and structural identification and characterization of sub-features and defects in display pixels. As display resolutions are getting higher pixels are getting smaller. InZiv said current inspection equipment lacks the resolution needed to identify and analyze defects on smaller pixels especially <5 micron. So an inconsequential defect in 50-micron size becomes a critical defect in 1-micron size microLED. InZiv’s equipment offers patented nano-optical inspection technology for light emitting pixel. According to the company, early detection of pixel defects results in substantial cost savings for display manufacturers improving quality and yield.  

Compound Photonics: Advance Microdisplay Technology
Compound Photonics introduced its IntelliPix™ all in one microdisplay drive technology platform that focuses to accelerate sub 5 micron pixel microLED development for AR/MR. It features multiple video pipeline and system integration and address power optimization, latency and bandwidth use. Combined with CP’s integration capabilities for microLED array bonding, device packaging, testing, and optical engine designs this opens new possibilities in display size reduction that is required for next generation AR display. The platform will be available for demo in early 2021.

NS Nanotech: Bringing NanoLEDs to market
NS Nanotech presented a paper on submicron full color LED pixels for microLEDs at the symposium. With breakthrough in material science and performance the company has been able to develop nanoLEDS. The company demonstrated a bottom-up approach to the construction of micro-LEDs as small as 150nm in lateral dimension. Molecular Beam Epitaxy (MBE) was used to fabricate such nanostructured LEDs from InGaN, from the blue to red regions of the spectrum, providing a single material set useful for an entire RGB display. By using their research the company has developed catalyst-free nano-column growth, disc-in-nanocolumn architecture and pure photonic band gap LEDs using monolithic RGB integration in a single process step. The product can deliver next generation performance for LED with REC 2020 color gamut, color stability, best in class efficiency and nano-micron size LEDs. With innovation and collaboration through the supply chain, the submicron full color LED pixels for microLED can bring breakthrough in product development.
Technology innovations and supply chain collaborations are really critical for next generation microLED displays to transform them from prototypes to successful commercial products with volume production that can compete effectively with OLED and LCD in future.
Sweta Dash, President, Dash-Insights
​
Sweta Dash is the founding president of Dash-Insights, a market research and consulting company specializing in the display industry. For more information, contact sweta@dash-insights.com or visit www.dash-insights.com
​

The Display Week 2020 conference was conducted virtually for the first time from August 3rd to August 7th and the online conference continues to be open until Dec 7th 2020.  With 180+ virtual exhibitors, seminars, symposiums, I-Zones and the SID/DSCC Business Conference, it gave a glimpse into the future of display in terms of market and technology.

Display Market Outlook:  Brighter for 2021
The Business Conference, organized in conjunction with DSCC, the provided display market outlook from analysts as well as executives from panel suppliers, brands, and equipment/material suppliers. According to DSCC's presentation, Covid 19 came when there was over-supply in large area and small/medium display market: panel prices were at a record low, panel suppliers had not made money for nine straight quarters and Korean suppliers are transitioning from LCD to OLED.
The impact of work-from-home and learn-from-home resulted in strong demand for tablets, notebooks and monitors. Even TV demand has recovered resulting in panel price increases. Mobile phones and auto displays are continuing to face negative demand growth rates. The global market is expected to be more display-centric after the Pandemic, leading to faster recovery. DSCC is forecasting a brighter outlook for display revenues in 2021. OLED will have higher equipment spending compared to LCD in 2020 and in future years. OLED displays will continue to gain market share from LCD. The Foldable OLED smartphone market is still developing. Demand is mostly focused on clamshell designs due to lower cost and less risk of damage. The Samsung Z flip is the most popular with robust design using ultrathin glass from Schott. High prices, ultrathin glass capacity constraints and still evolving form factors are limiting adoption rates for foldable smartphones.

OLED: Increasing Shares and Evolving Technology
OLED display with its superior performance and increasing share is still facing many challenges in terms of manufacturing complexities, yield, lifetime, efficiency of blue materials, power consumption and other issues. Display Week 2020 had many presentations from the global display industry, about technology development to resolve these issues. The smartphone market is expected to recover in 2021 boosted by 5G adoption. Flexible OLED displays are preferred for 5G products. Technology development is still needed to improve efficiency and lower power consumption.

• Cathode Patterning Material

As the smartphone market is shifting towards larger screen sizes, foldable displays and 5G, there is a greater need for lower power consumption and smaller battery size. OTI Lumionics showed how a patterned cathode in the OLED stack can enable high transparency ( for under display cameras & AR), higher brightness (mobile & automotive), low power consumption (5G & foldable), and larger size panels (foldable & QD-OLED). Their materials for cathode patterning are produced by PPG and have been qualified by multiple panel makers up to 6G lines. AMOLED modules with their products are being qualified with Tier 1 device makers and are expected to ship in 2021. The company said that their technology is enabling multiple customer applications: under display camera and face unlock, transparent display for AR, longer battery life and higher brightness for mobile, and larger size panels for foldable and QDOLED. Panel suppliers are currently pursuing different options for under-display camera and lower power consumptions. (more about this topic shortly - editor)

• Blue Material Development

High efficiency of blue OLED material is getting to be crucial to enable substantial power savings for mobile and IT products and enable high performance QD-OLED panel resulting in lower costs and higher resolution products. Companies such as UDC (Phosphorescence), Cynora (TADF), and Kyulux (Hyperfluorescence) are working towards developing the desired color, efficiency and lifetime. While there is progress it is not clear when it will be available. Current use of fluorescence material includes a deep blue color but with low efficiency. A paper from Samsung Display discussed how blue phosphorescent color purity and efficiency could be improved. 

• LTPO Technology

There were several interesting papers about LTPO by companies including Sharp and Royole. This technology is a combination of LTPS + Oxide TFT technology that enables variable refresh rates and low power consumption. LTPS has high carrier mobility and high driving capability whereas Oxide TFT has low leakage. It will enable a broad range of display applications with low standby power and high refresh rates. Apple the was first to use it in the Apple watch. Many companies are working on this technology for next generation displays. Samsung has already announced a Galaxy smartphone with variable refresh rates for 5G products resulting in lower power consumption. Samsung's Z fold 2 product has the first LTPO foldable display.

Ink Jet Printing: Starting Production
Ink Jet Printing (IJP) for advanced displays such as OLEDs has been investigated for more than 15 to 20 years. Printing technology has the advantage in terms of scalability of mother glass, and high efficiency in material utilization. It is already being used successfully for OLED thin film encapsulation (TFE) enabling flexible and foldable display. IJP for RGB OLED printing has been challenging due to material issues and manufacturing complexities. JOLED is the only supplier up to now to use IJP (Sumitomo polymer materials & Panasonic IJ printer) to commercialize 21. 6-inch,4K RGB OLED mid-size displays (currently used by Asus and Eizo as monitors). JOLED is also planning to produce 27-inch and 32-inch 4K OLED LTPS panels. It has also shown prototype of a printed 12-inch FHD flexible OLED sheet.
Increasing the substrate size of IJP can contribute to reduction in production costs. It is difficult to use LTPS TFT for larger lower cost displays. Oxide TFTs can be used for 8.5 G to 11G fab for printed OLED. RGB printing plus oxide TFTs can potentially contribute to high productivity in OLED display manufacturing. A printing method is required for RGB OLED TV panels for a top emission structure, as the Fine Metal Mask (FMM) method can’t be used. There are several advantages to printing including process simplification, investment and material cost reduction, smaller clean room space and a more environmentally friendly process. It will be also very valuable for next gen displays such as QDOLED, QNED, EL-QD and RGB OLED TV. CSOT/TCL invested $187 million in JOLED to scale up IJP technology for large size RGB IJP TV. DSCC forecasts that CSOT's RGB IJP OLED 8.5 Gen fab’s mass production will start in 2024. IJP prototype printers have been shown scaled to Gen 8 sizes by various equipment makers including TEL, Kateeva and SEMES.

QLED, QDOLED, QNED: Entering The Expansion phase
Samsung Electronics has been focusing on QLED (QDEF LCD) TV.  According to Nanosys’s presentation, the QD TV model proliferation rate is nearly double that of OLED TV resulting in more choices for consumers. QD TV set prices have reached below $1K enabling higher adoption and stronger growth rates. According to the DSCC’s Inkjet Printing presentation, Samsung Display is converting an 8.5 Gen LCD fab to QDOLED.
Samsung Display plans to invest $11 billion in next generation displays, which will include QDOLED and QNED. Samsung will convert 120K substrates/month of a-Si LCD capacity to 30K substrates/m QDOLED capacity in the first phase. Eventually Samsung Display plans 8.5 gen capacity to be converted to 100K/m QDOLED capacity. QNED is currently in the R&D phase and will progress to pilot line in 2021 if successful. According to the presentation, it is possible thatthe  QDOLED process line planned for the future may be converted to QNED where blue OLED will be replaced by Nanorod LED. Both Nanorods and QDCC (QD Color Convertor) can be deposited by IJP. Although advances are being made in EL-QD, its commercialization is beyond several years. EL-QD has advantages over OLED including high brightness, low power consumption, wider color gamut and potentially lower costs. EL-QD material performance still can be a challenge, and others include the lifetime of Cd-free EL-QD, Blue EL-QD, ink formulations and yield.

MiniLED, MIcroLED: Bringing competition to OLED in future
Mature LCD technology still continues to improve with the help of dual cell LCDs, miniLED backlights and QD technology improving contrast ratio, color gamut, luminance and HDR performance. Companies such as BOE and CSOT/TCL are focusing on dual cell LCD for TV. MiniLED backlights offer thinner backlight structure, high-density dimming zones and low halo effect for better HDR. A large number of zones can reduce the halo effect. Market for miniLED backlights is increasing for TV, automotive, monitor and notebook applications. MiniLED backlights outperform OLED in terms of brightness, image sticking, lifetime and narrow borders.
MiniLED-based LCD products have the potential to offer competition to OLED especially if cost can be reduced.
At Display Week, many companies presented papers focused on improving transfer, inspection and manufacturing technology for MicroLED. Vureal presented their printing process where MicroLEDs are printed directly from a cartridge to a display substrate selectively, and scalable to high volume production. It has multi cartridge transfer and multi color cartridges compatible for TV.  V Technology presented prototype systems and processes of laser lift off (LLO), mass transfer, electric bonding and color conversion layer. MicroLED-based displays have emerged as leading display solution to bring AR/MR glasses to the market due to their power efficiency and simple optics. Rohinni (with a joint venture with BOE) presented how to achieve high volume manufacturing. MicroLED is considered to be the next generation technology and making steady progress towards commercialization.
Display Week conference has always been the place to get a glimpse of future technology. It continues to deliver that even in a virtual setting. (SD)

Sweta Dash is the founding president of Dash-Insights, a market research and consulting company specializing in the display industry. For more information, contact sweta@dash-insights.com or visit www.dash-insights.com
 

MiniLED display technology can open up new opportunities for display application markets by offering higher specs and differentiated products. The global pandemic and slower economy have compounded the impact of slower display market demand. LCD has been facing over-investment, lower demand and low profitability. It has already pushed top suppliers such as Samsung Display and LG Display to move away from LCD production.
However, miniLED backlight technology (MiniLED-Based Displays Poised for Expanded Presence) can empower LCDs with very high contrast ratio, ultra high brightness, better HDR, thinner form factors and lower power consumption to compete directly with OLED in the high-end display application market.
​

MiniLED: For High-end TV

TV market demand has slowed down in recent years even though there has been a major shift towards larger screen sizes (55-inch and higher) and higher resolution (4K, 8K) displays. LCD TV (a-Si) has dominant share of the market but OLED TV has been gaining strong market shares in the high-end with thinner form factor, higher contrast, wider viewing angle, deeper black level, better color gamut and faster response time.  Still it faces burn-in, lifetime, image retention and limited supply issues.
LG Display is the only supplier for OLED TV panels. Samsung Display is planning to manufacture emissive QDOLED in future years. Samsung Electronics has been gaining market shares in the high-end with higher specs (8K) and more competitive priced Quantum Dot(QD)-based (LCD) TV. MiniLED with full array blinking backlight can improve LCD performance significantly. Performance can even improve further with QD technology. Suppliers are hoping that possible market recovery in 2021 and Olympic Games will require higher-specs products to revive the market.
TCL was first to introduce miniLED backlight-based Quantum Dot TVs in sizes of 65”(<$2000) and 75”(<$3000) in 2019. At CES 2020, the following products were shown.

• TCL: 75-inch 8K TV with 25,000 miniLED, >10,000 dimming zones on a glass black plane.
• LG: 8K miniLED-based LCD TV concept capable of reaching 4000 nits brightness.
• Konka: 8K miniLED-based TV with 40K miniLEDs and 10K zones.
• Vizio: 8K miniLED-based TV concept.
• BOE: 8K TV miniLED-based panel with a glass backplane, planning to launch in 2020.

According to Taiwan-based news sources, Samsung is reported to be preparing launch of miniLED TV in 2021. Multiple TV brands are also expected to introduce miniLED-based TV products by next year. MiniLED component suppliers are starting to report strong demand for miniLED packages for TV in 2H 2020. The global pandemic situation may delay some product launches to 2021.
With a high number of miniLED and dimming zones, each zone can be turned on and off selectively empowering LCD TV with high contrast ratio, better HDR performance, higher luminance, deeper black level, better power consumption, thinner backlights and longer lifetime. There are new requirements for Energy Star 8.0, which measures energy consumption in a dynamic display content mode, which can help to highlight the energy efficiency of miniLED backlights.
MiniLED-based TV used less efficient passive matrix driving technology in 2019. With an increased number of zones, companies are shifting to active matrix driving technology in 2020, which is more efficient and cost effective. Panel suppliers such as AUO, Innolux, BOE and CSOT are all developing active matrix-based products, which will help adoption rates.
Smaller size chips, better die bonding and more efficient production, combined with lower open cell LCD TV panel are enabling lower cost TV. Currently the TCL 75-inch 4K miniLED-based TV price is lower than similar OLED products. Many brands will pursue multiple TV technology strategies with LCD, OLED, QD and miniLED-based LCD TV together.  With the right price/performance strategy MiniLED can have great opportunities in the TV market in the next few years.

MiniLED: For Gaming Monitors, Notebooks and High-end Tablets

At CES 2020, a series of gaming monitor based on Quantum Dot technology were introduced with miniLED backlights and a higher number of Full Array Local Dimming (FALD) zones. That enabled products with very high contrast, deeper black level, higher color accuracy, high efficiency, higher peak brightness, and greatly improved picture quality.

• Acer and Asus: Both had a QD MiniLED 32-inch 4K G-Sync gaming monitor with 1152 dimming zones, 1400 cd/m² (nits) peak brightness, improved contrast and 90% of BT 2020 color gamut vastly improving picture quality.
• Lenovo: 27-inch 4K professional monitor with miniLED backlight (1152 zones), 1000 nit peak brightness.
• MSI: 17.3-inch mini LED based gaming notebook with 240 local dimming zones with >10K miniLED chips.

Acer, Asus, Lenovo and MSI are all expected to release their monitor and notebook products by the second half of 2020. With a miniLED backlight, an LCD can bring color contrast and display performance close to OLED. It outperforms OLED in terms of luminance and lifetime, important for gaming monitors. Generally OLED has an inverse relationship with luminance and lifetime. Companies are using pixel-shifting algorithms to reduce impact of burn-in in OLED monitor and OLED is gaining interest in high-end monitor segments with products from some suppliers.
The current price of miniLED-based gaming monitors are very high, > $3000 which can be a challenge for high adoption rates. According to published industry information, Apple is expected to introduce six products using miniLED backlight displays by the end of 2020 and 2021 including the iPad Pro and MacBook Pro. This may create a new wave of demand for miniLED-based products over the next few years.

MiniLED:  For Auto Display

Growth in electric, connected and autonomous cars will drive auto display demand. LCD is still the dominant technology in this application but interest in OLED is growing due to the higher display performance and flexibility in design. MiniLED technology offers very high contrast and brightness (sunlight readability), long lifetime, ruggedness in wide temperature range and can be used for displays with curved surfaces, offering design flexibility. However, there are difficulties in achieving qualification of OLEDs for automotive use, which shouldn't be a problem for miniLED LCDs.

• Innolux: 10.1" active matrix auto display with miniLED backlight, that can achieve 1000 cd/m² brightness, 1,000,000:1 contrast ratio and very high sunlight readability.
• AUO: 12.3-inch LTPS curved cluster panel 750 R curved and 1000 nits brightness.

MinLED LCD auto displays can also be used for dashboards, in-vehicle infotainment and rear view mirrors.  Suppliers are already delivering samples for design wins.


MiniLED: For VR ApplicationsMiniLED backlights with local dimming and low MPRT  can work well for high PPI VR LCDs. Active matrix miniLED backlights with LTPS backplanes can provide higher resolution and slim design, and switchable mode which are preferred for VR LCD.

• AUO: 2.9-inch LTPS display, 2304 dimming zones, pixel density 1688PPI, active matrix miniLED backlight based display for realistic VR experience with HDR

MiniLED: For SmartphonesDisplay panel suppliers have shown MiniLED backlight options with LTPS offering higher contrast, and faster response time to reduce the performance gap with OLED.

• Tianma: LTPS miniLED HDR LCD smartphone display, with local dimming (with up to 4600 partitions), >1,00,000:1 contrast ratio, >1,000nit brightness, high color gamut, (DCI-P3) and wide viewing angles.
• CSOT: 5.99inch LTPS display (1080x2160), 500nits, >1,00,000:1 contrast ratio with miniLED backlight.

However, miniLED backlight-based LTPS LCD cost is still high and the thickness can’t match flexible OLEDs. OLED has been gaining market share in the smartphone market. Capacity is increasing with flexible OLED smartphone panels coming from China, which will lead to lower prices in future. All these factors will make it very difficult for MiniLED to succeed in the smartphone market.


MiniLED – Road to SuccessDisplay suppliers such as AUO, BOE, Innolux, CSOT and Tianma have been showcasing prototypes of miniLED backlight-based LCD products in different sizes and applications since 2018. Costs, yield rates and production issues have been very challenging for higher adoption rates.
Recent developments can help drive miniLED based LCD to higher success.

• Need for higher specs and differentiated product: low demand, lower prices and low profitability requiring innovations to drive demand growth
• Top brands adopting miniLED technology: Apple adoption of miniLED could be substantial for the industry similar to how OLED in iPhone drove OLED investments, production and demand. Samsung launching a miniLED TV could drive demand higher.
• New equipment for cost effective volume production: The K&S joint development with Rohinni “Pixalux”, enables high-speed transfer with high accuracy and yield, for cost effective volume production, integrated with testing and repair to replace defective die by laser technology.
• Higher collaboration: among suppliers within the MiniLED supply chain including substrate, LED epitaxial wafer, packaging, driver ICs, display suppliers and even consumer electronic companies.
• Higher investment and capacity: Display, LED, backlight and other suppliers from Taiwan/China increasing investment and capacity.
• Higher competition and production from many suppliers: can lead to price and cost reductions, helping adoption rates.

MiniLED based LCD products can open up new opportunities for the display application market with higher specs and differentiated products in coming years. (SD)
Sweta Dash, President, Dash-Insights
Sweta Dash is the founding president of Dash-Insights, a market research and consulting company specializing in the display industry. For more information, contact sweta@dash-insights.com or visit www.dash-insights.com

MiniLED display technology can enable LCD to achieve high brightness, very high contrast, better HDR (High Dynamic Range), thinner form factor and higher power efficiency to compete directly with OLED. MiniLED-based displays were introduced in 2018, but trade issues in 2019, and global pandemic in 2020 have delayed suppliers’ expansion plans and product introductions.  Suppliers are now starting to increase capacities and investments.
The supply chain is evolving. Top consumer brands such as Apple are expected to introduce miniLED-based products by the end of 2020 and in 2021 for multiple applications. Cost is still the biggest challenge.

​MiniLED: Different from microLED

MiniLEDs are very different from microLEDs in terms of manufacturing process and their application markets. MicroLED can be considered as a revolutionary technology that will enable creation of a new self-emissive displays. MiniLED is a more evolutionary technology that can empower LCD backlights by helping in a reinvention process for most applications (high-end tablet, notebooks, monitors, TV, auto display, VR and others). It can also be used as a direct lit RGB LED for commercial applications like digital signage or control rooms.
MicroLED display still needs a technology breakthrough in mass transfer, higher manufacturing yield and significant capital investments to commercialize as reported earlier "MicroLED Display:  Progressing Towards Commercialization". However, miniLEDs can use existing fabs without major investments.


MiniLED: Enables Higher Display Performance

MiniLED-based display products were first introduced in 2018. Compared to microLED, this technology has higher manufacturing yield and is easier to mass-produce.

• In terms of LED size, miniLED lies between traditional LED and microLED. According to the current general consensus I have heard, microLEDs are mostly <50 microns in size; miniLEDs are generally 100 to 200 microns; and traditional LEDs are generally higher than 300 microns.
• By the use of multi zone blinking backlights (>10,000 zones), miniLED can enable LCD to have higher brightness (>1000nits), very high contrast (>10,000:1), excellent HDR, better color rendering, ultra thin form factor, superior power efficiency and display performance close to OLED.
• Due to miniLED’s small size, it can enable curved form factors and narrow bezels.

OLED can have a true black state and excellent contrast being an emissive display, but to achieve >1000nits it requires relatively high current which can impact lifetime. LCD can achieve >1000 nit brightness by increasing the number of LEDs but contrast ratio is very limited. MiniLED can resolve these issues. For HDR, pixel level dimming is best which is possible with microLED technology. MiniLED with multi zone blinking backlight can work as an alternative for higher HDR with >100000:1 contrast ratio and higher peak brightness. HDR is expected to be an essential feature for next generation display products.

MiniLED: Increasing Capacity

Major LED chip companies such as Epistar (Taiwan) and Sanan (China) are increasing capital expenditure to increase capacity. They are installing equipment for high-speed transfer, die testing and sorting to improve manufacturing yield.
Equipment suppliers such as Kulicke & Soffa and AMSPT are focusing on high-speed transfer and bonding while suppliers such as FitTech, Saultech are providing sorting and testing equipment. K&S and Rohinni have co-developed miniLED placement solutions. The development of tools that can increase throughput efficiently and handle smaller dies (<100 micron), can reduce manufacturing costs.
As miniLED technology uses a large number of small size LEDs, the process of testing and repairing is very important to reduce repair costs and improve yield. Testing and sorting companies are starting to report strong growth in demand from Taiwan and China. Driver IC companies such as Taiwan’s Macroblock are focusing on miniLED products this year. Most of the miniLED capacity is expected to come by the end of 2020 and in 2021.


MiniLED: Evolving Supply Chain

There are currently more collaborations among suppliers within the miniLED supply chain: substrate, LED epitaxial wafer, packaging, driver ICs, display suppliers and even consumer electronic companies. Panel suppliers are collaborating with their LED subsidiaries: AUO with Lextar and Innolux with AOT and other companies.
Epistar and Lextar announced a recent partnership to reduce overlapping investments and share production capacity for micro and miniLEDs. LED chip company Sanan is working with Samsung, while BOE has joint venture with Rohinni.
MiniLED supply chain companies such as BOE, China Star, AUO, Innolux, Epistar, Sanan, Lextar, Macroblock, ASM Pacific Technology, Nationstar, Refond, Yenrich, and many others are all working to develop better solutions. Consumer electronics companies are also joining in the collaboration and development.
According to published industry news, Apple is reportedly investing over $300 million to produce miniLED and microLED in Taiwan in conjunction with Epistar and AUO. The industry is buzzing with expectations about the possibility of a Apple 12.9” miniLED-based iPad Pro product introduction by end of 2020 or in 2021. Apple is reportedly planning to release six miniLED products by the end of 2021 including 14-inch and 16-inch MacBook Pro models, a 27-inch iMac Pro, a 10.2-inch iPad and a 7.9-inch iPad mini, including a 12.9-inch iPad Pro. Apple’s adoption of miniLED technology will have a very positive impact on the supply chain and growth potential.


MiniLED: Cost Challenge

Cost is a big challenge for miniLED. Cost reduction can be realized through advance chip production and higher throughput for the transfer and assembly process and PCB and driver IC enhancements. Chip production can be improved through reductions in chip size, improvements in uniformity and boosting luminous efficiency.
Epistar is changing the beam angle of LED chips using proprietary reflectors leading to a reduction in the number of chips used. Upgrading transfer and assembly efficiency and accuracy can also improve manufacturing yield. Panel suppliers are switching backlight connection backplanes to use glass with active driving solutions to reduce costs.
Most of the suppliers in the miniLED backplane market are also paying attention to microLED. Some suggest that processes such as faster bonding, faster transfer, precise backplane that are being developed in next few years for microLED can also help miniLED to reduce costs. That could enable miniLEDs to shift from incremental cost reductions to substantial cost reductions. Panel suppliers and component suppliers are expected to focus more on cost reductions in 2021 to support brands’ product introduction of miniLED-based displays to drive growth and expansion plans.
According to the LEDinside research division of TrendForce,
“the manufacturing cost of Mini LED backlight displays is currently higher than that of traditional LCD and OLED displays. However, as manufacturers continue to make improvements in process technology and yield rate, the cost of Mini LED backlight displays is expected to undergo 15-20% YoY deceases and to potentially be lower than the cost of OLED displays by 2022, making Mini LED a cost competitive option in the market. “

MiniLED: Application Market

MiniLED-based products are already being shipped for high-end monitors and TV. Display panel suppliers have shown many prototypes of miniLED-based products at DisplayWeek 2019:

• Tianma (HDR LTPS LCD smartphone)
• CSOT (5.99” LTPS LCD smartphone)(15.6” LTPS notebook) (12.3” curved LTPS LCD auto display)(65”, TV 2000 nits, BT2020 color gamut)
• AUO (17.3”, 4K, HDR, notebook) (12.3”, curved auto display) (2.9”, LTPS LCD, 1688PPI for VR)
• BOE (15.6, oxide LCD, 240Hz, HDR notebook).
• TCL was first to introduce miniLED backlight based QD TV in 65”(<$2000) and 75”(<$3000) in 2019.
• At CES 2020 consumer brands showcased: Acer and Asus (QDLED 4K G-Sync gaming monitor BT 2020).
• Vizio unveiled a miniLED backlight-based 8K LCD TV
• MSI announced first 17” 4K laptop with miniLED display
• TCL showcased Vidrian 8K TV by directly infusing miniLEDs into glass substrate greatly increasing performance.

​MiniLED costs have gone down recently due to increased efficiency and lower chip costs. It still faces cost challenges to become competitive. With Apple’s introduction in tablet and IT products more brands are expected to follow. In the near term, suppliers are focusing more on value-based applications such as high-end tablet, notebook, gaming monitor, TV, automotive and VR.
MiniLED-based products can open up new opportunities for the display market. It can enable LCDs with higher performance, thinner form factors and lower power consumption to compete with OLED and drive replacement demand with higher specs. MiniLED-based products are poised for expanded market presence. Success will depend on its ability to reduce cost to drive demand. (SD)

Sweta Dash is the founding president of Dash-Insights, a market research and consulting company specializing in the display industry. For more information, contact sweta@dash-insights.com or visit www.dash-insights.com

microLED is considered by some to be the fourth generation flat panel display technology after plasma, LCD and OLED. It combines the best features of LCD and OLED, with higher brightness, significant increases in power efficiency and reliability and the potential for lower cost. Many working prototypes have come to market but no volume production yet. microLED display is Progressing Towards Commercialization(my last Display Daily article). Can microLED compete with LCD and OLED in the display application market?

Super Size Display:  Video wall, Signage, Public display, TV..
Samsung showcased a modular 146-inch microLED TV called “The wall” at CES 2018, and followed it with a 219-inch version in 2019 and a 292-inch in 2020. These products were based on microLED chips where die sizes were larger than 50 microns, and products were based on a passive matrix mode. Very large size self-emissive displays with >50 microns die size are considered as miniLED display rather than microLED

• At CES 2020 Konka showed a 236-inch microLED technology based large display and LGE showed a 145-inch screen.
• Samsung’s 75-inch microLED TV with active matrix driver based on Playnitride <50microns chip, modular LTPS backplane, was first showcased at CES 2019.
  • Samsung plans to produce 75-inch and other size microLED TVs by 2021, in partnership with Epistar and Playnitride.
• Sony first demonstrated a 55-inch FullHD microLED TV based on its crystal LED technology in 2012 but it was never commercialized.
  • Sony has started selling modular crystal LED super size displays targeting applications such as boardrooms, theme parks, museums, retail showrooms, corporate lobbies, studios, and other commercial markets.
  • Sony's display is based on active matrix driving technology integrating RGB microLEDs and micro ICs and provides true black with a high contrast ratio even in a bright environment.
  • The system has scalability: with no bezel they can be tiled up to a large-scale display system seamlessly with free size and free aspect ratio.

These super size commercial displays are very expensive and can cost hundreds of thousands of dollars. The displays are targeted for commercial products and can compete directly with direct LED video-wall products. With very high brightness, true black, very high contrast, design flexibility, microLED super size displays can provide higher performance with low power consumption. But to increase adoption rates, cost has to come down: die size has to go down, but that will reduce efficiency and lifetime.
It will be extremely challenging for microLED TV to compete with LCD, QDLED, OLED and even miniLED TV in the near term. Industry experts believe die size for microLED TVs has to go down to <10microns for 4K TV and <5 microns for 8K TV to be more price competitive.
By the year 2021 and 2022 about eight to ten 10.5 Gen fabs with huge capacity are expected to be in production making LCDs and AMOLEDs. Samsung Display is also working on QDOLED TV products. It will be extremely hard for microLED display to be price-competitive in the 75” and below consumer TV market.

Small Size Display: Wearable, Smartwatch..
Wearable products such as smartwatch and activity tracker have a real need for thinner, lighter, lower powered, flexible displays. Their small size displays need high resolution and higher brightness for outdoor use with longer battery life. microLED can meet these requirements and outperform the currently dominant OLED display.

• Apple is reportedly working on microLED after acquiring Luxvue and is said to be setting up MiniLED and microLED fab ($334 million investment) in Taiwan in partnership with AUO and Epistar.
• RiTdisplay & PlayNitride have shown a 1.25" display with a glass substrate and 0.9-inch flexible display.
• Glo has shown a 1.6" (JDI) and 1.8" (Kyocera) full color microLED wearable display (LTPS backplane).
• Apple is currently using 1.57-inch and a 1.78-inch AMOLED display for Apple watch products. Apple may be introducing microLED wearable in 2021.

If Apple does shift to microLED from OLED for smartwatch it will have a significant impact on the display industry. Apple could also follow the strategy of using microLED only for premium models and OLED for others. To reduce costs,  a die size design of <20 microns is needed for microLED. Its high brightness and significantly lower power consumption ability can be a real benefit for battery-powered devices like smartwatches.

Very Small Size Display: AR, VR,..
The extremely high brightness capabilities of microLED can be a major advantage for devices such as AR, VR and HUDs (Heads Up Display) where waveguides are commonly used to place images in a headset or in glasses in front of the eyes (due to light loss issues). Even though microLED has many advantages for micro-display applications, there are also challenges such as efficiency, full color technology, and better control of defective pixels.
The VR/AR market is expected to grow in the next five years.
VR - Companies such as HTC and Oculus have developed more stand-alone, all-in-one devices for VR with lower prices. OLED display has been gaining higher acceptance in the VR market due to its high refresh rates, higher resolutions, and higher contrast for either direct view or micro display. microLED can match and exceed OLED performance. Its lower power consumption and lower battery size capability can transform bulky VR sets to lighter versions.
AR - microLED with high brightness, high resolutions and low power consumptions can enable flexible design and light weight AR glasses. Apple is expected to introduce AR smart glasses within a few years. AR adoption has been slow due to high prices and low consumer acceptance. Products such as Microsoft Hololens, Google’s Glass seem to be more accepted in the enterprise and vertical market rather than the consumer market.

• Jade Bird Display - 0.31" monochrome green micro-display for AR/VR (3 million nits, 5,000 PPI) and a 0.3" monochrome blue micro-display (150K nits, 10K PPI)
• VueReal - 30K PPI, 100K nits MicroLED microdisplay
• Glo - full color microLED for AR/VR head set based on RGB LED
• Plessey - 1080P microLED for AR/MR, 0.7inch blue monochrome MicroLED displays (using JDC’s silicon backplane)
• Plessey and Compund Photonics - co-developed 0.26-incg integrated MicroLED display module for AR/MR application
• Pleassey - GaN-on-Si technology. It recently announced its agreement with Facebook/Occulus for product development

As it can be seen from the above, monolithic microLED microdisplays can achieve very high brightness and resolution. Many consumer electronic companies are evaluating GaN-on-Si LED epiwafer (better cost than GaN-on-sapphire) for their microLED production. It can reduce cost and increase yield in manufacturing scalable to 200mm and even 300mm and also by using current CMOS facilities.
For a full color solution, sometimes QDot color conversion technology can be beneficial. Nanosys and DIC corporation have jointly demonstrated the possibility of inkjet-printed QD as the color conversion layer on microLED array. MicroLED has the potential to challenge OLED in the wearable and VR/AR market.

Medium Size Display: Automotive..
At CES 2020 many companies showed end-to-end design solutions for AR head-up displays (HUDs) including Altia, BMW and Futurus Technology. Futurus was showing MR (Mixed Reality) technology for safe and immersive experiences in next generation vehicles. Technology can move towards smart window-shielsd in future, combined with safety and entertainment info. MicroLED can provide higher brightness and higher reliability for HUD applications.
AUO and Playnitride have co-developed a 9.4-inch flexible microLED display, with a PI- backplane geared towards auto display market. The company used same technique as flexible OLED to remove PI from a substrate after transferring the display devices. AUO has also demonstrated 12-inch microLED display with LTPS glass backplane for auto applications. The auto display market with its long design cycles may take a few years before mass production.

Transparent Displays
VueReal has shown a MicroLED array with>60% transparency and 200 ppi resolution using a micro-printing process. Tianma exhibited a 7.56- inch transparent full color microLED with a LTPS glass backplane with Playnitride chips. China Star has shown a 3.5-inch transparent IGZO glass-based backplane. Application targets for these displays are still evolving. Some believe this can help microLED to provide product differentiation in the market to compete with traditional LCD and OLED.
Implications for the Application MarketThe LCD and OLED industries and products are moving targets, both still improving in performance and reducing their costs. Can microLED potentially match the price and performance of LCD and OLED? In theory, it can. But as history has shown, theoretical potential takes years to be realized and sometimes never gets there.microLED display has the potential to be successful in many different application markets. (SD)


Sweta Dash is the founding president of Dash-Insights, a market research and consulting company specializing in the display industry. For more information, contact sweta@dash-insights.com or visit www.dash-insight.com
 

microLED is considered to be a next generation display technology. It provides the best features of both LCD and OLED display. It has the potential to outperform both the technologies in terms of color reproducibility, brightness, reliability and low power consumption.
Many working prototypes have been introduced, but it is not in volume production yet due to manufacturing challenges, cost issues and the need for supply chain establishment. Technology developments and new solutions are coming, leading to steady progress towards commercialization.

Display Suppliers:  Increasing Activities
According to recent press release from Yole Development,
“..analysts estimated that cumulated effort in microLED to date reaches close to $4.8Billion, with Apple alone close to $1.8 billion, factoring in both the Luxvue acquisition and internal developments”.

They identified and selected about 5500 microLED related patents filed by more than 350 organizations. The press release reported that 40% of the patents were filed in 2019 alone. China and display makers are driving this exponential growth. BOE now leads in volume with close to 150 new patent families in 2019.

Currently the display industry is going through a great transition. Samsung Display and LG Display (Korea) have decided to stop LCD production due to low profitability. Suppliers from China are dominating the LCD market with their massive 10.5 Gen capacity. Samsung (the dominant OLED supplier) and LGD are focusing on OLED and next generation technology (Quantum dot, microLED). China suppliers are also starting to build OLED fab capacity. AUO and Innolux (Taiwan) are focusing more on microLED as they didn’t invest in OLED capacity. Major display suppliers -  Samsung, LGD, AUO, Innolux, BOE, Tianma, CEC Panda, Visionox and others are all increasing their activities in microLED display which will help to establish the supply chain for volume production.

microLED Suppliers:  Bringing in Prototypes
According to industry estimates, more than 130 companies are working in the microLED display supply chain. Besides panel suppliers, many startup companies and component suppliers as well as top brand manufacturers are exploring solutions for microLED products including Apple (LuxVue), Facebook/Oculus (mLED, InfiniLED), eLux (integrated with Foxconn group), Aledia (Intel), Lumens, Lumiode, Jade Bird Display, Mikro Mesa, Play Nitride, Plessey, Glo (Google), VueReal, X-celeprint (X-Display), Rohinni, Sony, Visionox and others.
Here are some of the microLED display prototypes announced in the 2019/2020 timeframe.

• AUO & PlayNitride - announced a 9.4" (228PPI) flexible display (PI LTPS) for automobile application. AUO also introduced a 12.1" (169PPI) panel in 2019 (LTPS glass)
• RiTdisplay & PlayNitrite - introduced a 1.25" display with glass substrate and 0.9-inch flexible display based on thin film (both 228ppi resolutions, scheduled mass production 2020). According to industry news sources, both companies may be in talks with Apple to produce a next generation watch/wearable display.
• Samsung - showcased “The Wall” large format TV products at CES 2020 in 292", 150", 110", 93", and 88" using larger size chips. It also showed a 75" (4K) microLED TV based on smaller size chips from PlayNitride.
• Glo - has a 1.6" (JDI) and 1.8" (Kyocera) full color microLED display (LTPS backplane) and showed a full color RGB LED display for AR/VR.
• Plessey - demonstrated a 1080p microLED near eye display solution for AR/MR
• Jade Bird Display - has shown a 0.31" monochrome green micro-display for AR/VR (3 million nits, 5,000 PPI) and a 0.3" monochrome blue micro-display (150,000 nits, 10,000 PPI)
• PlayNitride & Tianma - have shown a 7.56" RGB full color transparent display with LTPS backplane (114PPI, >600nits, 60% transparent). The have also shown an extremely thin (28um) flexible display and a 1.25" 458dpi wearable display.
• CSOT - showed a full color 3.5" transparent display (IGZO glass backplane).
• X-Display - exhibited a 5.1" (70PPI) display
• VueReal - announced a 30K PPI, 100K nits MicrolED microdisplay in May 2019

Technology development prototypes with lab scale productions are very different to commercialized products. To compete with TFT LCD and OLED in the consumer market microLED products need to have zero defects, high performance, high uniformity, high consistency, high volume scalability and cost competitive manufacturing. Products sometimes take years to shift from prototype to commercialization and some never even make it to the market.

Complex Manufacturing Issues
microLED is a self-emitting display technology consisting of arrays of microscopic LEDs each forming a pixel. It is simple in structure compared to OLED and LCD but has a complex manufacturing process. The microLED supply chain consists of the following steps.

• GaN epiwafer preparation
• Processing of thin film LEDs on the wafer
• Mass transfer of the chips to the display backplane
• Inspection and repair processes

Display integration of microLED can be generally of two types. One is heterogeneous integration, where microLED arrays use pick and place process, and chips are transferred from an epiwafer or carriers to the display backplane (LTPS or Oxide TFT in glass or flexible PI substrate). The other one is monolithic integration where process involves microLED arrays and backplane hybridization.

Mass transfer -  of microLED devices is a critical enabler for cost competitiveness with TFT-LCD and OLED. Companies such as eLux are offering technology that moves microLED from the wafer to a substrate in a fluidic process where the microLED get dispersed in liquid and wells built on the substrate create a self-assembly system. The target of the tool is to work on Gen 6 LTPS substrates in the future. Collaborations of PlayNitride, Unimicron Corp (PCB backplane), and Macroblock (driver ICs) have shown the use of mass transfer of microLEDs into printed circuit board backplanes, which can reduce production costs. Startup company VueReal has developed micro printing technology that can make different sizes and different resolutions high density microLED micro-display.

Yield - Manufacturing and yield problems can become an issue in epitaxy, chip, mass transfer, bonding, driving technology, backplane, inspection and repair. Integration of in-process testing, redundancy and repair are used to improve yield. The industry is working to resolve these issues.

Uniformity - microLED chips need wavelength uniformity and thickness uniformity for display applications. Solutions from MOCVD suppliers such as Aixtron, Veeco and others are helping to resolve such issues. For example Veeco is collaborating with Allos (provider of GaN epiwafer technology) to achieve extremely good emission wavelength uniformity. The Aixtron MOCVD solution AIX G5+C and Planetary® technology is enabling high volume manufacturing of products with high-level wavelength uniformity and low defects that can help to increase yield and lower costs.

Testing - microLED companies also need to use mass testing and repair methods to reduce the cost and time of assembly. Companies such as Toray are working on equipment for microLED wafer inspection, repair and transfer. Laser repair equipment can remove defective microLEDs and then selectively transfer good microLEDs to complete the repair process.

Color Conversion - The mass transfer process that performs the bonding of RGB (Red Green Blue) microLEDs to the display backplane accurately and efficiently is very challenging. Also different colors of LED need slightly different voltage and drive currents. Color conversion by quantum dots or by phosphor provides another alternative. Using single-color (blue) microLED chips and color converting them with quantum dot layers can help in the manufacturing process. Nanosys has demonstrated a photo lithography-patterned cadmium free color conversion layer for microLED.

Supply Chain Development
microLED still faces many challenges in terms of mass transfer, mass inspections/repair, and supply chain establishment.

• There is no standard manufacturing solution for commercialization.
• Startup companies are mostly fabless with licensing capabilities, but they need partnership for manufacturing. Large established companies are reluctant to depend on single startup for their supply.
• Suppliers with LTPS-TFT capacity for backplane or other manufacturing capabilities need to invest capital for transfer, inspection/testing, and create path to mass market.
• Panel suppliers and set suppliers need to be confident about profit margins for business. Current market condition makes it difficult for display suppliers to invest capital in this new technology.
• Set makers are currently driving microLED chip decision strategy to improve product performance.

More partnership and collaborations among panel makers, set makers and microLED chip makers are required.

Application Market
microLED display have a strong potential to outperform TFTLCD and OLED as they offer high contrast, fast response time and wide viewing angles. The technology can also provide wider color gamut, very high brightness, higher readability, long lifetime, environment stability, high resolution, ultra low power consumption for mobile devices and options of using a flexible backplane. It also allows the integration of sensors and circuits, enabling thin displays with embedded sensing capabilities such as fingerprint identification and gesture control.
Companies are initially targeting wearable, AR/VR, digital signage, public display and automotive (HUD) applications. High-speed transfer, assembly technologies, yield and defect management need to improve before large volume commercialization in consumer products such as smartphones or TV.

Road to Commercialization
microLED display technology is making steady progress towards commercialization. However the technology faces several challenges, which will take more time to resolve. In the meantime, suppliers will test the market with higher priced, lower volume, value-based products. Samsung plans to commercialize a 75" microLED TV based on PlayNitride chips by 2021. Apple may be also introducing microLED based wearables by next year.
Success in commercialization and mass production will depend on the ability to scale up for volume production with competitive price performance - SD
Sweta Dash, President, Dash-Insights

Sweta Dash is the founding president of Dash-Insights, a market research and consulting company specializing in the display industry. For more information, contact sweta@dash-insights.com or visit www.dash-insight.com
 ​

Technology breakthroughs in the display industry have been enabling innovative consumer products. This year’s CES conference showcased many examples of this as products based on MicroLED, QLED, OLED and MiniLED dazzled attendees with their image quality, performance and designs.

MicroLED:  Progressing in Size

Samsung impressed the attendees with their biggest TV ever with a 292-inch 8K TV based on MicroLED technology. The modular TV will be available in many different sizes (75, 88, 93, 110, 150) and the modules can be combined for different shapes, some with slim and bezel-less designs. LGE showed a 145-inch TV while Chinese brand, Konka, showcased a 236-inch 8K MicroLED TV. Samsung is planning to go into MicroLED TVs production soon. Still, at the moment, extremely high price and manufacturing challenges will lead to very limited shipments.

MicroLED is a self-emitting display, which consists of arrays of microscopic LEDs each forming a pixel. It is simple in structure but has a complex manufacturing process. It has the potential to create thinner, brighter, lighter, higher contrast and low power displays, but products are not yet commercialized or in mass production. MicroLED displays can be used for TV as well as for applications such as wearable devices, AR/VR headsets, automotive, smartphone and others.

In smaller sizes, AUO showed a 12-1-inch TFT driven full color MicroLED auto display; ITRI showed a display where the sensor functions are integrated into pixel; Plessey showed a monolithic 1080P MicroLED based near-eye display solution for AR/MR, and Jade Bird Display showed MicroLEDs for AR/VR with extremely high brightness (up to 3 million nits).

Many companies are working to resolve manufacturing, yield and costs issues to enable volume productions for consumer products. There are still many challenges to be solved which will take a few more years to overcome.

QLED: New Products, New Designs

Samsung unveiled its very impressive flagship Q950TS QLED 8K TV which has

• an ultra thin form factor (only 15mm even with full array local dimming (FALD) backlight),
• an “infinity screen” (very thin bezel that produced 99% body to screen ratio),
• built in 8K AI up-scaling capabilities, and AI quantum processor.

Samsung is trying to position these TVs as the central hub for connected living with AI, voice assistance and many other features. The company is also trying to increase adoption of 8K by bringing it to many sizes and price points. Samsung also showed a unique design with its “Sero”, 43-inch 4KQLED TV that can shift from landscape to portrait mode like a smartphone.

Besides Samsung, Vizio (a new 85-inch FALD and a series of other models), Hisense (expanded QD TV line up), Konka (the company's QD TV for U.S) and others also demonstrated Quantum Dot TVs at CES, most coming in 2020. TCL pushed the quantum dot technology performance even further by combining it with a miniLED backlight. According to TCL, by infusing micro-metre class MiniLEDs directly into a glass substrate, its Vidrian 8K TV is able to achieve stunning contrast, brilliant luminance, enhanced color and stable long life performance.

Quantum dot saw expansion in the gaming monitor side with Acer and Asus showing the latest versions of their QD MiniLED display technology with 1152 local dimming zone on 4K G-Sync monitors significantly improving picture quality and reaching 90% BT 2020 color gamut with Nanosys' Quantum dot technology. QD displays will be entering an expansion phase in 2020 with lower prices, more brand availability of TVs in many sizes and price points and expansion into monitors and notebooks. During Black Friday sales, Samsung’s QLED TV reached $499 for 43-inch and $999 for the 55-inch size. TCL’s 65-inch QLED TV was available in Costco for $599. Lower retail prices for QD TVs will drive demand.

OLED-Flexible, Rollable, Foldable

At CES 2020 LGE showed 65 RX, its rollable OLED TV that can roll up from a box. It is expected to ship in 2020. The industry buzz is that it will be very expensive around $60K. LG Display showcased a concept of a very impressive rollable TV that can roll down from ceiling. Th flexibility of OLED display technology has enabled many innovative consumer products in recent years and more will be coming.

To showcase its newest processor ‘Tiger Lake”, Intel unveiled the largest foldable PC, codenamed “Horseshoe Bend”. It is a 17.3-inch OLED device that folds like a laptop but opens up to be a 17.3-inch desktop monitor. Lenovo launched its foldable PC Thinkpad X1 fold (only 2.2 pounds) with a 13.3-inch OLED display. The display can be seen in full screen, one-screen plus keyboard mode or dual screen mode and folds into an ultraportable size. Dell showed ‘ORI” a large folding tablet that can close like a book (availability mid 2020). Samsung demonstrated a Galaxy Chrome 2-in-1 laptop with a high performance 4K OLED.

Foldable smartphones, enabled by flexible foldable OLEDs, started entering the market at the end of 2018 with Royole’s Flexpai. Samsung, Royole and Huawei already have first generation foldable smartphones on the market in the $1300 to $2600 range. Higher prices along with reliability and design issues have resulted in limited shipments in 2019. Starting from 2020, foldable smartphones will be shifting more towards a new clamshell design away from the folding book type. Most of the smartphone announcements will happen at MWC (mobile world conference in February). TCL showcased a working prototype of a foldable phone with 5G at CES 2020 and announced a 5G smartphone at "less than $500" this year.

LG Display showed a first class airplane cabin concept using a transparent OLED, that can also works as a privacy screen, and a 65-inch bendable OLED TV for an immersive experience. LGD also showed a flexible rollable plastic OLED for passenger seat entertainment that can roll up and down and disappear behind the seat.

Many companies showcased autonomous car concepts where they used bended curved display extensively. Royole showed an Amazon Alexa-enabled speaker with its 8-inch fully flexible wrap around OLED.

OLED TV has secured a strong presence in the premium TV market. The introduction of 48-inch OLED TV will help the technology meet lower price-point needs. Brands such as LGE (48-inch to 88-inch, 4K, 8K, wall TV, gaming TV G-SYNC capable), Sony (>=48, 4K,8K), Panasonic (brighter higher performance display), Vizio (first time OLED TV), Hisense and Konka all showcased various sizes and types of OLED TV. LG Display is the only supplier for OLED TV panel, leading to limited supply. LGD is converting LCD TV capacity to OLED and is also investing an additional 3 trillion KRW into a Gen 10.5 OLED production line, mainly producing >=65-inch TV panels. It is planning to almost double the TV panel production in 2020.

LCD: Reinvention with MiniLED, Dual-cell, QD
​
Hisense showcased a dual-cell LCD TV scheduled to arrive in the second half of 2020 (the concept was first introduced in 2019). Hisense XD9G TV uses two LCD modules for better viewing angles, higher contrast ratiso and deeper black levels than traditional LCD TV. Interestingly AUO showed a 12.3-inch Auto dual cell LCD pixel dimming curved display with true black level and a contrast ratio of over 100,000:1.

AUO also showed an 85-inch 8K bezel-less ALCD TV with advanced HDR, 1000 dimming zones. It also had a MiniLED based gaming display with 144Hz refresh rates and 2500 cd/m² peak brightness. Sharp showed the largest class 120-inch 4K and 8K LCD TVs.  Vizio unveiled a MiniLED backlight-based 8K LCD TV.  On the cover of 13.3-inch Thinkbook Plus, Lenovo used a secondary 10.8-inch E Ink display for notification and note taking. Many suppliers showed products based on MiniLED backlight that can enable LCD re-invention.

MiniLED backlight displays can offer higher contrast ratio, higher brightness, deeper black, and better power consumption. TCL was the first to introduce a MiniLED backlight-based QD TV in 65-inch (<$2000) and 75-inch( <$3000) in 2019. The products have received very positive reviews. MiniLED-based products are already being shipped for high-end monitor and notebook applications. MiniLED costs have gone down recently due to increased efficiency and lower chip costs. It still faces cost challenges to become competitive. In the near term, suppliers are focusing more on value-based applications such as TV, gaming, automotive and VR. 
​
Technology breakthroughs in MicroLED, Quantum Dot, OLED and MiniLED backlight technology have enabled consumer products with larger screen sizes, higher brightness, better contrast, higher color gamut, lower weight and many unique designs which were showcased at CES 2020 pushing the envelope of next generation display products. (SD)

Sweta Dash is the founding president of Dash-Insights, a market research and consulting company specializing in the display industry. For more information, contact sweta@dash-insights.com or visit www.dash-insight.com