In November 2022, Insight Media and a few select other invited guests, were allowed to take a tour of Samsung Display’s Asan Korea fab that is producing the company’s QD-OLED panels. We were told this was the first time any external personnel had been allowed to take such a tour. While we only saw a few specific stations, the facility is very impressive.
Before the tour, we first sat down with the marketing team, headed by Chirag Shah, who provided a briefing on what Samsung Display will announce at CES 2023 (which is why this post appears at CES and not in November). New will be a 77” 4Kx2K panel and a 49” 8Kx2K panel. These and the other scvreen sizes will also feataure an increase in luminance and power reduction.
SDC made good on their promise to increase in light output, as we reported from our meeting at the SMPTE conference. Peak luminance in a 3% window will increase from 1500 nits to 2000 nits. While a 3% window sounds small, it looks bigger than you would expect on a TV-sized display (bigger than a dimming zone on high-end miniLED TVs). Even with a bigger 10% window, luminance will be 1300 nits, up from 1100 in 2022 models.
This increase is not done with any new thermal management techniques or lens arrays, said Shah, but through a combination of refinements. This includes a “hyper-efficient” blue OLED layer (not with new phosphorescent blue OLED materials, but possibly with an optimized electron transport layer), minimization of light absorption, and enhanced light resonance. Remember, the QD-OLED display uses a blue and green OLED layer on an oxide backplane with ink-jet-printed red and green quantum dots. They have also added improved pixel control and a real time optimizer. Overall, they say lifetime (or reliability) has nearly doubled from 2022 models.
Shah says that the QD-OLED panels also use less power. This is important for Europe where new energy efficiency rules are set to go into effect in March 2023. The Energy Efficiency Index (EEI) metric for 4K displays is set to reduce from 1.1 to 0.9. Current 55” and 65” QD-OLED sets come in at around 1.1 but the new sets can meet the 0.9 limit.
Data was presented showing the 2023 QD-OLED panel luminance (in a 3% window and maximum code value) vs. a 2022 White OLED panel (from a competitor), as shown in the table below. The differences in luminance are significant with the color light output metric showing how the white pixel can de-saturate colors at high luminance levels (i.e. 39% of the luminance comes from the RGB sub-pixels). The color gamut for the QD-OLED panel remains above 90% of the BT-2020 color gamut with a much “purer” white than the WOLED. These latter panels can exhibit a magenta hue when calibrated to a D65 white point.
|Color Light Output
The 2023 QD-OLED panels also exhibit 50% less color shift at a 60-degree angle moving from a delta-u’ delta-v’ color shift value of 0.012 to 0.006 in the 2023 models.
Shah also noted that the pixel structure remains the same as the 2022 models, which some have criticized for exhibiting a color fringing in fine edges. Shah said that they use a top-emitting structure instead of the bottom emitting structure of white OLED and there is no sub-pixel sharing. The color fringing problem is real, but hard to find. Ordinary consumers will not notice it.
The 2023 TV panels, including the new 77” version, will support frame rates up to 120Hz while monitor panels, including the new 49” version, can go up to 144 Hz. Gray-to-gray transition time is speced at a small 0.1 ms and monitor makers will be able develop products that support Nvidia GSync Ultimate, AMD Free Sync Premium Pro, TrueBlack and low blue light certifications.
The invited guests were next ushered from the meeting room over to the ASAN 2 campus which is composed of three large fab buildings (right side of photo).
Guests need to strip down to their underwear, put on pajama-like garments before donning the clean-room bunny suite. We were outfitted with communication devices and earbuds to facilitate explanations and questions during the tour, which we started after passing through an air-jet chamber.
Once inside, the tour was conducted in Korean and translated to English by our guide. We were to tour the fourth floor of the fab where the frontplane is fabricated including deposition of the OLED stack, ink jet printing of QD materials and encapsulation. The second floor is where the oxide TFT backplane is fabricated.
This fab has been operational since November 2020. Initial yields were around 50% but have now risen to around 90%. On the tour, we were impressed with the scale of the facility and the size of the machines needed to move and process Gen 8.5 glass. It is a fully automated facility and we only saw a few people on our tour.
The tour was brief but there were a few interesting take aways:
- X-Ray machines were everywhere and are used to eliminate static electricity that can build up as parts move through the line.
- The quantum dots emit in a Lambertian pattern, but the blue is OLED sub-pixel has a different emission pattern. As a result, there is a process step to add a diffusing material over the blue subpixel to make it a Lambertian emitter.
- They use a plasma etcher to clean glass
- They use a multi-mother glass masking technique to optimize panel layout on the glass substrates.
- Ink jet printing lays down multiple dots or lines at a time.
- They could not say what the smallest printable feature size was
- Mass production of the new 77” and 49” panels will begin in early 2023
- Samsung Electronics was not allowed on the tour. They take this separation seriously as SDC supplies to other TV makers as well.