Recovery In Flat-Panel Display Biz

The flat-panel display market is starting to recover after a period of oversupply and lackluster growth, fueled by new technologies as well as more people working from home.

The flat-panel display market is complex. Several different technologies are at play, such as liquid-crystal displays (LCDs) for TV screens and other products, as well as organic light-emitting diodes (OLEDs) for smartphones. Cars, industrial equipment, PCs and tablets all incorporate flat-panel displays in one form or another. And for many products, the display is a big selling point for consumers.

For the flat panel market as a whole, 2019 was a tough year. Oversupply caused prices to drop, which in turn sparked some major changes in the landscape. Two South Korean suppliers — LG Display and Samsung — are retreating from the low-margin LCD business to focus on higher-end display technologies. Meanwhile, China-based suppliers have been building up a massive amount of fab capacity, with plans to dominate several sub-segments in the arena.

2020 was supposed to be another gloomy year. Then, the COVID-19 pandemic struck. A large segment of the population was (and is still) forced to work at home due to the pandemic, disrupting the world’s economies. If there is a silver lining, the work-at-home economy is fueling demand for several products, thereby jumpstarting the display market.

“In 2020, who would have thought that the three fastest growing segments on an area basis would be tablets, notebooks and monitors? Those three segments had been in decline,” said Ross Young, CEO at Display Supply Chain Consultants (DSCC), during a presentation at the recent Display Week 2020 conference. “We are now talking about double-digit growth in display revenues in 2021 with a brighter outlook post-COVID than pre-COVID.”

Not all products categories are robust. Smartphone demand is a mixed bag, while TVs are plodding along. So in total, worldwide display demand is projected to grow by 1% in 2020 over 2019, according to Omdia. Display capacity also will grow by 1%, meaning supply and demand are in balance in 2020, they said. “In the meantime, we are expecting the industry will experience a ‘V’ shape recovery for 2021. Flat-panel display area demand growth will increase by 9.5% in 2021,” said David Hsieh, an analyst at Omdia.

Capital spending for displays also appears to be a bright spot, which is welcome news for flat-panel display equipment suppliers. “(There is a) continuing investment in large panels for TVs and a recovery in investment for OLED for mobile applications,” said Toshiki Kawai, president and CEO of TEL, in a recent presentation. In terms of capital spending, the industry “is expecting approximately 15% year-over-year growth in CY2000,” Kawai said.

Not all displays are alike. Each display segment is different with various dynamics. Among them:

• Apple and other smartphone OEMs continue to migrate from LCDs toward brighter OLED displays. Samsung is the leader in OLED fab production, but China is making a major push here.
• China also continues to build massive fab capacity for traditional LCDs.
• Many vendors are developing new display technologies for so-called advanced TVs and other products.
• Two other segments — microLEDs and miniLEDs —also are hot markets.

Fig. 1: Demand and capacity growth for LCDs, OLEDs and other displays. Source: Semiconductor Engineering from Omdia data

Smartphones and foldables
The smartphone display market is dynamic. Smartphone displays based on OLED technology continues to take share away from LCDs, and the new 5G smartphones will accelerate that trend. Plus, foldable phones and tablets using OLED displays are finally shipping after several false starts.

An LCD is a mature and inexpensive technology with several parts. A backlight module is on the bottom of an LCD screen, followed by a thin-film transistor (TFT) array, liquid crystals, a color filter (red/green/blue), and a polarizer.

LCDs consist of a multitude of pixels. A pixel consists of three sub-pixels—red/green/blue (RGB). “A change in voltage applied to the liquid crystals changes the transmittance of the panel, including the two polarizing plates, and thus changes the quantity of light that passes from the backlight to the front surface of the display. This principle allows the TFT LCD to produce full-color images,” according to Japan Display.

Meanwhile, active-matrix OLEDs (AMOLEDs) use a series of thin, light-emitting films, which enable brighter displays than LCDs. OLEDs are also flexible, but they are more expensive than LCDs.

LCDs and OLEDs are manufactured in fabs using an assortment of equipment. Korea is still the OLED leader in terms of fab capacity with a 67% share, according to Omdia. But China is making a big push here, as the nation’s share of OLED fab capacity has jumped from 1% in 2014 to 31% in 2020, according to the firm.

By 2022, China is projected to have 21 small- to mid-sized display fabs, including LCD and OLED. Some 14 fabs are in production in China with 7 in the works, according to the firm. China also is building new fabs for large-screen LCDs for TVs.

“In case of the OLEDs, China is aggressively investing in new capacity. But long-term, we also see that Korean OLED capacity will dominate,” Omdia’s Hsieh said.

On the product front, meanwhile, 70% of all smartphones use traditional LCD screens today, while 30% incorporate OLEDs, according to Omdia. By 2024, OLEDs will represent about 43% of the smartphone display market, they added.

5G, a next-generation wireless standard that is faster than today’s 4G, also will propel OLEDs. “AMOLED displays will grow, along with the 5G mobile phone market, due to their superior power consumption characteristics, which is lower than that of LCD displays,” said T.T. Yang, deputy division director of corporate marketing at UMC. “In addition, TDDI is the display driver IC with the touch controller function integrated on the same silicon chip, which has become very popular within the smartphone market over the past two years. It has started to expand into other applications for growth as TDDI has recently faced strong competition from AMOLED displays for smartphones. The new applications for TDDI include tablets, automotive display and others.”

Meanwhile, Samsung, the leading supplier of OLEDs, continues to improve the technology. Samsung developed a new OLED adaptive frequency technology, which reduces the power consumption of a display. “High-definition video streaming and gaming are expanding their capabilities in line with 5G commercialization, creating a widespread need for display panel technologies that can enable greater power savings,” said Ho-Jung Lee, vice president of mobile display products at Samsung Display.

Meanwhile, Apple’s iPhone 11 line consists of three models, including two OLED-based systems and one LCD product. For the upcoming iPhone 12, Apple will incorporate OLEDs in all models. The iPhone 12 also represents Apple’s entry into 5G.

Here’s what to expect for two iPhone 12 models: “The iPhone 12 Max is expected to be 5G using sub-6GHz technology and will feature a 6.1-inch flexible OLED sourced from BOE and LG Display with an add-on touch sensor and a rumored resolution of 2540 x 1174 or 460 PPI,” according to DSCC. “(The OLED for the) iPhone 12 Pro Max is expected to be exclusively supplied by Samsung Display and will have a 6.67-inch 2785 x 1293 flexible OLED panel.”

Other OLED segments also are growing. After years of hype, smartphones/tablets using foldable OLED displays are finally shipping. Samsung is shipping the Galaxy Fold, which features a 7.3-inch AMOLED display that can be folded into a compact 4.6-inch cover display.

Others are also developing foldables. The foldable phone/tablet market is expected to grow from 700,000 units in 2019, to 3.9 million in 2020, to 10.9 million in 2021, according to Omdia.

Foldable systems, however, face some challenges, such as power consumption, component readiness, mechanical issues and cost. Samsung’s Galaxy Fold sells for a retail price of $1,980, according to Omdia.

LCD TVs vs. advanced TVs
In terms of total area, LCDs for TVs represents the biggest market in the flat-panel display business. LCD TVs are commonplace today, but so-called advanced TVs are making inroads.

Bob O’Brien, president of DSCC, defines an advanced TV as a system with an advanced display. In the advanced TV arena, consumers have a dizzying array of technology choices — 8K, dual-cell, microLED, miniLED, OLED TVs and quantum dot TVs.

The advanced TVs incorporate dazzling displays, but they are expensive and the market is still tiny. “Turning to the long-term forecast, we expect that advanced TV shipments will grow from less than 10 million in 2019 to nearly 35 million in 2025, a 24% CAGR for that time period,” O’Brien said.

LCD TVs still dominate the consumer market, simply because they provide enough features at low price points. But LCD TV prices continue to tumble, forcing LCD vendors to develop and sell products at razor thin margins.

LCD TV technology is identical to LCDs for smartphones, but it’s on a much bigger scale. All LCDs are built in giant fabs using various equipment. The LCD manufacturing process takes place on an entire sheet of glass or substrate. Some glass sizes are the size of a garage door.

Today’s mainstream LCD TV fabs are based on Gen 8.5 and 10.5 technology. The term “Gen,” or generation, denotes the glass size. Gen 8.5 fabs produce panels at sizes of 2,200 x 2,500mm, while Gen 10.5 are 2,940 x 3,370mm.

The idea behind LCD manufacturing is to reduce the cost of the panel. To drive down the cost, a giant panel is fabricated in the fab and then cut into smaller displays. For example, Gen 10.5 fabs, the world’s largest plants, are ideal for making 43-, 65- and 75-inch LCD TV panels.

Nonetheless, in 2017, China took the lead over South Korea in terms of overall LCD fab capacity. In 2020, China will have 57% of the world’s TFT LCD fab capacity, according to Omdia. Taiwan is in second place (25%), followed by Korea (13%) and Japan (6%), according to the firm.

China continues to build LCD fabs. By 2022, China is projected to have 22 large-screen LCD display fabs. Some 15 fabs are in production with 6 in the works. That also includes China-based LCD fabs from both LG and Samsung, which are on the block.

The large-size LCD market is a tough business with thin margins. That’s why LCD makers are developing new and advanced displays with higher margins.

For example, LG Display is developing and selling large-screen OLED TVs with mixed results. OLED TVs have bright displays, but they are still expensive. OLED technology is similar for both TVs and smartphones.

OLED TVs continue to improve. At Display Week, LG Display presented a paper that outlined a new OLED display with a motion blur reduction technology. A key to the technology is a new gate driver IC. “The MPRT (moving picture response time) value of the 65‐inch ultrahigh‐definition OLED panels decreased by 3.4ms by using an integrated gate driver circuit,” said Hong Jae Shin, a researcher at LG.

OLEDs involve a complex manufacturing process, especially the development of the RGB sub-pixels. For this, a fine metal mask process is used to produce the sub-pixels.

Instead of the traditional methods, a company called JOLED is developing OLEDs using an inkjet printer. Using this technology, JOLED has developed 4K OLED monitors. “We have developed our own printing technology as a manufacturing method that can be developed in various sizes while maintaining high definition of over 200 ppi,” said Kazuhiro Noda, an executive officer at JOLED, in a paper at Display Week.

In another advanced TV category, Samsung and TCL are pushing quantum dot TVs. Quantum dots are inorganic semiconductor nanocrystals. When inserted into an LCD TV, quantum dots can boost the color gamut in the display.

8K TVs are also in the mix. Based on LCD technology, an 8K TV consists of a 7,680 x 4,320 screen, which equates to 33 million pixels, according to Samsung.

MicroLED, miniLED buzz
In displays, the big buzz revolves around two technologies — microLEDs and miniLEDs. Both are smaller versions of an older technology called light-emitting diodes (LEDs).

Traditional LEDs, which convert electrical energy into light, are used for backlights in LCD displays, billboards, consumer electronic items and lighting. LEDs come in different configurations, such as monochrome and multi-color. An RGB LED, one popular type, consists of the primary colors in the gambit. These can create a number of different colors.

The size of an LED is 200μm and above. In comparison, a miniLED ranges in size from 50μm to 200μm. Like LEDs, miniLEDs are targeted for backlights in displays.

Measuring smaller than 50μm, microLEDs are self-emissive and don’t require a backlight. In theory, a display using microLEDs provides more color and higher brightness with lower power than competitive displays.

“MiniLEDs, which are larger than microLEDs, are now being incorporated in consumer devices such as TVs,” said Subodh Kulkarni, president and CEO of CyberOptics. “But microLED is an even more exciting area of innovation that is poised for growth. The disruptive technology enables products that are brighter, thinner, lighter and more dynamic than those currently on the market, with lower power consumption than LCDs or OLEDs. Tiny microLEDs can also be placed on flexible substrates. These advantages will continue to propel this technology forward.”

Apple, Facebook and Samsung are just a few of the companies developing microLEDs. Companies are working on microLEDs for a range of applications, such as displays for AR/VR, TVs and watches.

But microLEDs are still several years away from being a mainstream technology. There are too many technical hurdles. “A major challenge is the small size and complex structure of microLED chips. For microLEDs, these dimensions are one to two orders of magnitude smaller than traditional LEDs,” said Steve Hiebert, senior director of marketing at KLA. “From a process control perspective, the transition to microLED displays creates a number of major challenges that must be overcome. In order to have economic viability, there are complicated tradeoffs between microLED size, wafer-level yield, microLED redundancy and microLED repair.”

In the microLED process flow, the first step is to make tiny LEDs on a substrate. It’s like a traditional LED process, which is mature and well known.

The next step is to fabricate a separate TFT backplane. The hard part is to transfer tiny microLEDs from the substrate to the backplane.

Take an 8K TV, for example. For this, a company must make millions of microLEDs in the fab and then transfer them onto the backplane at high speeds and with good yields.

“An 8K display requires close to 100 million individual microLEDs. To ensure proper interconnection and eliminate certain image artifacts, the required placement accuracy is typically ±1µm,” said Eric Virey, an analyst at Yole. “Today’s best die bonders can’t manipulate the very small die (3 to 15µm) required to enable high-volume consumer applications. In addition, they typically have throughputs in the range of 1,000 die per hour. At this pace, it would take more than 11 years for such equipment to manufacture a single 8K TV.”

To speed up the process, companies are developing new and faster transfer methods. For example, PlayNitride is developing a high-speed pick-and-place process. In another approach, V-Technology is developing a laser lift-off system.

Meanwhile, X-Vision Lab and Visionox are developing a color conversion process. The idea is to develop a single-color microLED. Then, the microLED is color converted using phosphors or quantum dots.

There are other approaches as well. Unlike microLEDs, which are still in R&D, miniLEDs are getting traction in tablets and monitors. “MiniLED backlights with the LCD is definitely the hottest topic in the IT area,” Omdia’s Hsieh said.

Several vendors are developing the technology. For example, AU Optronics (AUO) recently unveiled a 17.3-inch miniLED full-HD gaming laptop display with a 300Hz refresh rate. AUO also introduced a 27-inch 240Hz gaming monitor display using the technology.

In 2021, Apple is expected to roll out a high-end iPad using miniLEDs as a backlight. “The size is 12.9-inch, and the resolution is a high pixel density (2732 x 2048). One of the reasons for the Apple iPad to adopt the miniLED backlight is due to the very high color gamut,” Hsieh said.

The big issue with miniLEDs is cost. A 12.9-inch tablet with a traditional LCD is about $85, compared to $239 for a miniLED, he said.

The miniLED process is similar to a microLED flow. The first step is to make tiny miniLEDs, followed by the backplane. The miniLEDs are then transferred to the backplane using various transfer processes. This is not as difficult as the microLED process, but there are still some challenges.

For a notebook PC display, a vendor must make roughly 10,000 to 20,000 miniLEDs in the fab, according to Omdia. Each miniLED is transferred onto a backplane at high speeds.

Conclusion
Clearly, the flat-panel display market is dynamic. Smartphones are moving towards brighter displays. TVs are also moving towards bigger screens with better quality. And the advanced TVs offer dazzling screen quality.

Despite the innovations, it’s up to the consumer to decide what sticks. The screen quality is just one factor. As before, it often comes down to the prevailing factor–price.

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