PPI - Page 8

Taiwan-based Chunghwa Picture Tubes (CPT), in collaboration with European research institute imec (in the framework of the Holst Centre collaboration) have demonstrated an ultra-high resolution OLED display that was patterned using photolithography - without the need for an FMM (metal mask). A photolithography process offers a high aperture ratio, large substrate sizes and good yield control.

The prototype display that was demonstrated is a passive display with a 1400x1400 resolution (or 1250 PPI!) of side-by-side orange and green OLEDs. imec reports that preliminary lifetime investigation shows operation of each color after patterning for a few hundred hours at more than 50% of the original brightness.

At the iMID 2017 conference in Korea, AP Systems announced that it realized high density OLED evaporation using new FMM technologies. By adopting ultra-short pulse laser (USPL), AP Systems achieved a 1,000 PPI. Changing the pin-hole shapes, the company says this technology can even reach 1,170 PPI.

High PPI OLEDs are especially important for VR applications, which require much higher pixel densities as the display is used very close to the eye. In May 2016 Samsung demonstrated a 5.5" 3840x2160 - which reaches 806 PPI, and according to reports Samsung were able to produce a 1,200 PPI AMOLED in March 2017.

According to a report from Korea, Samsung is developing its next-generation Gear VR headset, which will include a built-in display (unlike current models which require you to insert your Galaxy smartphone into the device).

The report claims that Samsung will adopt a new OLED display in this device - which will achieve a pixel density of 2,000 PPI. Such a high pixel density will be great for VR as it will improve the realism and reduce sickness.

OLEDON announced that it has developed a plane-source evaporation shadow mask process that can achieve a shadow distance of 0.38um - which can enable OLED display resolution to reach 2,250 PPI. The company says it technology will be able to achieve 3,300 PPI in the future.

OLEDON is not alone in the development of plane-source evaporation technology. In November 2016 Sunic Systems announced that it developed a similar AMOLED production process - that can also achieve 2,250 PPI. It may be that Sunic and OLEDON are collaborating on this, it is not clear.

Canada-based VueReal has developed a 4K Micro-LED microdisplay (6000 PPI). The company plans to finish the verification and evaluation this year and provide samples to several interested customers by October 2017. In 2018 VueReal will start mass producing such displays for niche customers and aim to license its technology for display makers.

VueReal says that its "Continous Pixelation" Technology enables it to achieve low-power high brightness (10,000 nits) high-density displays at very high yields and at an affordable price.

Google's VR vice president, Clay Bavor, revealed that Google has partnered with "one of the leading OLED makers" on a secret project to develop a high-end VR display. The OLED display will support a resolution of 20 million pixels per eye.

This is a very high resolution - a 4K display has 8.3 million pixels, so it means 2.5X the number of pixels in a 4K display. It terms of display density (which depends on the panel size of course, which we assume to be around 3.5"), this could be around 1,800 PPI.

JOLED announced that it started to sample 21.6" 4K OLED monitors. These monitors, demonstrated in March 2017, feature a 3840x2160 resolution (204 PPI), a brightness of 350 cd/m² and a contrast ratio of 1,000,000 : 1. The panel thickness is 1.3 mm and the weigh is 500 grams.

JOLED aims to start mass producing these panels in 2019, but will also attempt to sell these to the medical market even in low-volume production out of its current 4.5-Gen pilot production line.

According to an industry insider in Taiwan, Samsung is set to acquire Taiwan's PlayNitride for the company's micro-LED technology for around $150 million. Our inside says that Samsung aims to develop micro-LED based displays for VR applications, but may also look into micro-LED based TVs using PlayNitride's technology.

Micro-LED is a promising display technology as it has the potential to enable brighter and more efficient displays compared to OLEDs. It also may be cheaper, but there are still technical challenges to overcome and analysts estimate that micro-LEDs will not be commercialized before 2020.

JOLED (Japan OLED) was established in August 2014 by Japan Display, Sony and Panasonic with an aim to become an OLED medium display (10-30 inch) producer. The company is aiming to start mass production in 2019, although some panels may ship in limited volume earlier.

Last week at Cebit 2017 JOLED demonstrated some of its latest OLED prototypes. In the photo above you can see JOLED's 21.6" 4K (3840x2160, 204 PPI) "medical applications" monitor. JOLED also demonstrated what seems to be the same panel for "consumer" application (they call this private viewing). The whole panel weighs just 500 grams and the color gamut is 130% sRGB.

According to the Korea Herald, Samsung Electronics demonstrated several new display technologies in a private room during the Mobile World Congress last month. All of these technologies are expected to enter production within the next year or two, according to the source quoted by the report.

1,200 PPI AMOLED for VR

The report claims that Samsung demonstrated a high-resolution AMOLED panel for VR applications. The AMOLED on display featured a 1,200 PPI - much higher than Samsung's current highest density displays which are 577 PPI. Samsung's aim is to reach 1,500 PPI which will greatly enhance the VR experience.

In November 2016 Sunic Systems announced that it developed an plane-source evaporation-FMM based AMOLED production process that can reach very high densities. The 100um mask announced in November can achieve a PPI of 1,500. This may be the system that Samsung is now testing. Sunic says that eventually this technology will enable even 2,250 PPI.