Will Samsung Return to OLED TV?

Published February 26, 2018

Several reports this week indicated that Samsung may be contemplating a new effort to make OLED TV, but a statement late in the week seemed to dispel these rumors, at least for now. The world’s biggest TV maker will continue to push for innovative technologies in TV displays, and since Samsung is the dominant player in OLED displays for phones, rumors about their participation in OLED TVs are about as common as Russian athletes doping at the Olympics.

A few years ago, Samsung had announced that OLED was the future of TV. At the CES show in January 2012, Samsung revealed their plan to introduce OLED TVs, starting with a 55” Full HD (1080p). While both Samsung and LG were pursuing OLED TV at that time, their approaches were fundamentally different in their display architecture, in several aspects:

  • Backplane: LGD chose an oxide TFT backplane, while Samsung pursued LTPS
  • Deposition: LGD chose White-OLED through an open mask and a color filter, Samsung went with RGB OLED through a fine metal mask
  • Emission Orientation: LGD chose bottom emission, while Samsung chose top emission
  • Encapsulation: LGD went with a metal encapsulation, Samsung with glass

In several ways the choices made by LGD are sub-optimal. The use of White OLED with a color filter reduces the brightness efficiency. Bottom emission reduces the aperture ratio, which further reduces brightness efficiency. To compensate for the lower efficiency, LGD has added a white sub-pixel to increase brightness, but this adds complexity in the backplane and reduces color gamut at peak luminance. All of these drawbacks, though, are outweighed by one factor: LGD was able to manufacture their White-OLED TVs at an acceptable yield, whereas Samsung never achieved mass production with good yield, and gave up the effort to make OLED TV by 2015.

Samsung’s push for TV innovation via Quantum Dots and Micro-LED is not without its problems. Although Samsung remains the #1 brand for TV worldwide and in the US, its position in the US has slipped a little in terms of market share, especially among the premium segment over $1000 (“TV Shopping on Christmas Weekend – No Deals”, DSCM 12.26.2017). In that premium segment, Samsung faces not just LG but also Sony brand TV sets using LGD OLED panels, and both Sony and LGE have consistently achieved higher operating margins in their TV business than Samsung (see Figure 1).

Therefore, it’s quite natural to think that Samsung will return to OLED technology to boost its fortunes in TV. The Korean site ETNews reported last week that Samsung’s Display division (SDC, not the TV division which is Visual Display) is restarting OLED TV research and development. SDC is organizing 300-400 researchers for its OLED TV R&D, under a large TV business unit led by a large-size LCD TV Vice President. ETNews reported that the researchers would be pursuing oxide TFT technology as well.

The ETNews article also introduced an intriguing new concept, the QD OLED. This new technology approach combines the benefits of quantum dot technology with those of OLEDs and has an interesting roadmap. One implementation includes the use of the blue OLED as the light source with red and green added through a quantum dot color filter. The idea of a quantum dot color filter has been made more realistic by the recent announcement of a breakthrough in quantum dot printing (“Nanosys and DIC Announce Breakthrough on Quantum Dot Printing”, DSCM 12.03.2017).

The attractiveness of QD OLED can be seen by comparing its structure to that of LGD’s White OLED approach, shown in Figure 2. The White OLED stack includes 17 layers deposited on the substrate (p/n Charge Generation Layers represent 2 layers each time), plus four sub-pixels.

Figure 1: Quarterly Operating Margins of TV Divisions of Top Three Brands

Figure 2: LGD White OLED Stack Structure

In contrast, the hypothetical QD OLED product architecture includes only ten layers in the OLED stack (see Figure 3). With the expectation that quantum dots can efficiently convert blue light to red and green, the QD OLED offers the promise of better brightness efficiency than white OLED, and better color saturation at peak luminance.

There’s just one big problem with the QD OLED approach: it relies on blue OLED, which is the weakest link in OLED displays. Commercially available OLED displays for both TVs and smartphones use fluorescent OLED blue emitter material, which is substantially less efficient than the corresponding red and green phosphorescent emitters supplied by Universal Display Corporation (UDC). Therefore, this Samsung QD OLED rumor was coupled with a related UDC rumor, that UDC would announce a commercially available phosphorescent blue material in its earnings call on February 22nd. Unfortunately for UDC investors (see "UDC Completes Terrific 2017, but Has Trouble in 2018," DSCM 02.26.18), the company made no such announcement, and phosphorescent blue does not seem to be imminent.

Figure 3: Representation of QD OLED

It should be noted that the blue OLED with a red and green QD color filter is not likely the only implementation of OLEDs and QDs. In terms of manufacturing, the blue OLED can either be put down with an open mask VTE system or ink jet printed. Since no patterning is required in the implementation in Figure 3, we would expect an open mask VTE system to be used as a VTE system is still needed for the common materials and it would just require an extra chamber for the blue OLED. In addition, the red and green color QD color filters can be deposited via photolithography or ink jet printing. Photolithography would likely be the faster and high yielding solution while ink jet printing would have lower material costs. However, we heard rumors that Samsung may be looking at the implementation in Figure 3 as the first step towards ink jet printing QLEDs. So, Samsung may next explore printing blue OLED emitters and red and green QD emitters. Would such a system work? Soluble blue OLED emitters are well short of where they need to be from a lifetime perspective, but are making great progress. UDC’s organic vapor jet deposition could be a solution here, but would they use it for just one color? While Samsung depends on other companies for OLED materials, it is developing its own quantum dot materials and will likely to look to incorporate them into its TVs sooner than later. It would certainly look to incorporate a high efficiency blue OLED material from UDC or Cynora, but may also likely look to incorporate a blue QD material from its QD material group once its lifetimes have matured. At that point, Samsung will have developed a true QLED, which will create less confusion for its customers and from a branding standpoint. Will a true QLED TV outperform an OLED TV? It appears Samsung believes it will.

The ETNews article on QD OLED erroneously reported that Samsung demonstrated 55” and 65” QD OLEDs at the CES show in January 2018. DSCC’s Ross Young reported on the Samsung Display exhibit (“Inside the Samsung Display Suite – Foldable, OLEDs and QDs Impress”, DSCM 01.15.2018), which included an 18” QD OLED prototype, not the larger TV sizes. However, the ETNews article has enough information to make the rumor credible, and it gained credence by a similar article from Business Korea saying that the restoration of OLED TV activity was ordered by Samsung Electronics Vice Chairman Lee Jae-yong after his departure from prison.

In response to these rumors, Yonhap News reported that Samsung Visual Display’s Vice President Han Jong-hee denied the story, saying that Samsung is sticking with its two-track strategy for the premium TV market, developing both QLED and MicroLED TV displays. Although such a statement would seem to dispel the idea of QD OLED TV, those who watch Samsung closely know that its business divisions are fully independent. The denial came from Visual Display, but the rumored QD OLED activity was not in Visual Display but in Samsung Display, a different division.

It should also be pointed out that Samsung had no choice but to deny the OLED TV development efforts because if it acknowledged them they would be conveying to consumers that OLED TVs are superior and encouraging customers to buy from LG now and delay purchases from Samsung. Any acknowledgement would certainly minimize claims by their TV group around their 2018 TVs, which look to be a significant improvement over their 2017 line with the adoption of local dimming backlights producing higher contrast ratios and darker black levels.

Samsung Visual Display will hold a special product launch event in New York City on March 7th, and Bob has received an invitation to the event which will launch Samsung’s US product line, to be led by Han Jonghee. I look forward to reporting on this event to DSCC subscribers

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Written by

Bob O'Brien