PPI

TCL CSoT demonstrated several OLED displays at CES 2024. first up we have an automotive 10.1” transparent OLED display, that offers 52% transparency. CSoT says that this is a "Smart Transparent" display, although it's not clear what is meant by that exactly.

The second display is a 14" 2.8K (2880x1800, 240 PPI) inkjet printed hybrid OLED. This is the first time that CSoT has printed a laptop AMOLED display. It uses an IGZO (Oxide-TFT) backplane, and offer a variable refresh rate (30-120Hz) to expand the battery life. This display was first shown last month, when TCL stated it is on track to start mass producing OLEDs using an inkjet printing process in the second half of 2024.

Samsung Display announced that it is beginning to produce a new 31.5" 4K QD-OLED. This is SDC's highest density QD-OLED display, at 140 PPI. The company recently upgraded its QD inkjet printing deposition system to support this higher resolution. It will also enable SDC to produce 8K 65" QD-OLED displays (that will also be 140 PPI). 

Samsung Display also announced that next year it will start producing 27" QHD QD-OLED monitor panels that will support a 360Hz refresh rate, targeting the gaming monitor market. 

During Display Week 2023, the institute demonstrated its latest displays, including the world's highest-density OLED microdisplays, reaching a PPI of 10,000 with a pixel size of only 2.5 um.

Fraunhofer's 10,000 PPI display was e a 0.18" 1440x1080 (monochrome) panel, produced on 300 mm wafers, using a 28 nm backplane process. The Fraunhofer also showcases ultra low-power microdisplays, and more technologies.

Universal Display announced that it will detail advances in its latest PHOLED materials at Display Week 2023. The company's latest red, green, and blue PHOLED materials offer a narrow emission spectrum, which increases the efficiency of OLED devices, in addition to enhancing the color gamut.

UDC also unveil a new OVJP system printed on a 200mm x 500mm Corning Astra Glass substrate. UDC will also showcase the first-ever fully printed seven-layer (HIL/HTL/EBL/EML/HBL/ETL/EIL), 80 PPI, green commercial-level PHOLED device fabricated by its R&D OVJP system that has comparable device performance with vacuum thermal evaporation (VTE). 

The Fraunhofer FEP research institute announced that it has developed the world's highest-density OLED microdisplays, reaching a PPI of 10,000 with a pixel size of only 2.5 um. The Fraunhofer will demonstrate a 0.18" 1440x1080 (monochrome) OLED microdisplay next week at Display Week 2023.

The new microdisplays were produced on 300 mm wafers, using a 28 nm backplane process. The Fraunhofer explains that most OLED microdisplays to date are produced on 200 mm wafers, using CMOS processes ranging from 90-250 nm. The institutes new technologies enables the the performance increase in OLED display processing. 

Visionox is introducing a new OLED production technology, called Visionox Intelligent Pixelization (or ViP for short) that enables higher-density display production, at over 1,700 PPI.

The idea behind ViP is to replace the fine metal mask (FMM) method with photolithography-based pixel patterning. The process offers several advantages, mainly the increase of aperture ratio to almost 70% (Visionox says the currently reach 69%). FMM methods usually achieve up to 30%, which means that brightness, efficiency and lifetime can all be increased.

In 2021 The Korean government launched a new project that aims to develop technologies for the production of OLED microdisplays for AR applications. The project is led by AP Systems (APS Holdings), and aims to produce a direct emission OLED microdisplay with a resolution of 4,000 PPI by 2024. Earlier this year APS developed FMM masks that reached 1,000 PPI.

APS now announced that it has produced a 3,000 PPI direct-emission OLED microdisplay, based on its FMM technology. This is very impressive progress.

LG Display has demonstrated a 12" 100 PPI full-color stretchable MicroLED display. The display can stretch up to 20% (to create a 14" display).

The display is said to be "close to commercialization" - as it is highly flexible, durable, and reliable. LGD says that it is the world's first full-color high-resolution stretchable display that was ever produced. But we do know that companies have demonstrated stretchable OLED displays in the past, for example Samsung with its 13" stretchable display shown in 2021.

Yang Joon-Young, a VP at LG Display, says that recent improvement in OLED technologies will cause an industry shift from LCoS devices to OLED microdisplays in AR systems. LCoS will find a market in low-cost AR headsets, but most AR solutions will be based on OLEDs.

Next-generation VR systems, which will require higher pixel densities, will also switch from LCD and mobile AMOLED displays to OLED microdisplays that will offer pixel densities of over 3000 PPI.

In 2021 The Korean government launched a new project that aims to develop technologies for the production of OLED microdisplays for AR applications. The project is led by AP Systems (APS Holdings), and aims to produce a direct emission OLED microdisplay with a resolution of 4,000 PPI by 2024.

According to reports from Korea, APS Materials has managed to develop a 1,000 PPI FMM mask, and is now building a new R&D line that will be used to produce direct emission OLED microdisplays using FMM technology. The new APS production line will include OLED deposition and encapsulation.