Display and Optics Manufacturing: How Applied Materials Will Tackle the AR/VR Challenge

Published November 1, 2021

This week, DSCC is hosting the AR/VR Display Forum, a two-day virtual event (November 3-4) on display technologies for augmented reality and virtual reality. DSCC took the initiative to organize this Forum because the display is a key component to deliver the user experience promised by both AR and VR.

Applied Materials is a Platinum sponsor and will present their latest manufacturing innovations during the conference. The company has kindly agreed to answer a few questions ahead of the event. The answers below were provided by Applied Materials’ executive staff: Robert Visser, Max McDaniel, Paul Gallagher and Nag Patibandla.

DSCC: Please can you introduce your company? Which technologies from Applied Materials are in displays manufactured today?

We are the world’s leading display and semiconductor equipment maker. For Displays, we make deposition equipment like CVD and PVD for building thin-film transistors to drive pixels of LCD, OLED, and other displays. We also provide deposition equipment, like thin-film encapsulation, for manufacturing OLED frontplanes. We also provide e-beam based yield management equipment for testing TFTs and measuring defects, critical dimensions and other film and device properties.

DSCC: How important is AR/VR for a company like Applied Materials? How many projects are currently running?

When you consider the amount of electronics and the need for more and better processing and storage at even lower power requirements, the promise of AR/VR is incredibly important to Applied’s core business. When you consider the requirements for the display optics, the same tools and technologies needed to make advanced semiconductor chips can be used to create waveguides. Applied Engineered Optics group is focused on transitioning these tools and technologies to enable the manufacturing of nanostructured waveguides. We see this technology as strategic and a strong growth opportunity going forward.

DSCC: So, the waveguides are important for see-through optics. Do you see AR as more challenging than other display applications?

Every display technology has its issues that make it challenging, with AR the issues are multi-layered and, in many cases, still under development.

For surface relief gratings, like those made by Applied, you shine the display source output into a nanograting on the surface of the glasses, which causes the display data to traverse through the surface of the glass, bouncing between the front and back of the glass surface while also expanding the projected scene size until it hits a second grating. This grating redirects the bouncing imagery out to the user’s eye. The alignments required between the display and the input grating, the input grating to output grating (remember different wavelengths of light will travel different paths within the glass) and then the alignment of the output grating to the user’s eye position all have to be dealt with.

Nanostructured waveguide technology is quite young, the technologies, processes and capabilities to make waveguide structures that are repeatable, well formed at a high slant angle, and with gapless encapsulation pushes current fabrication technologies. On top of all that you need to deal with the glass material itself, traditional displays have a glass surface this is on the order of a millimeter or less thick, for AR the light will travel the equivalent of multiple centimeters through the glass. There is significant light absorption through the surface of the glass at a level that more traditional displays do not have to deal with, this puts more pressure on the grating capabilities to be very efficient. All these issues together are part of what makes the display optics for AR very challenging.

DSCC: Many new VR headsets are now based on LCD because of the high pixel density (measured in pixels per inch or PPI). How can OLED manufacturers compete in this space?

Both LCD and OLED need innovations to reach the desired PPI for VR headsets. For OLED, one solution is to make micro-OLEDs, using crystalline silicon wafer backplane and a high-resolution OLED frontplane. With this technology, resolutions of >3000ppi can be achieved. There are also efforts in the industry to develop higher-resolution OLED devices on glass than what is currently available, but these are still in development.

DSCC: Do you think microdisplays, such as MicroLED (µLED) on silicon CMOS backplanes, will reach a cost low enough for consumer devices?

Microdisplay applications have a set of demanding performance requirements such as high brightness, high pixel resolution, low power consumption, fast refresh rate, etc. µLED based front plane technology meets these demanding performance requirements. However, the industry needs to address the engineering challenges of small dice at less than 3 microns with high photon extraction efficiency, difficulties with multiple mass transfers steps (µLEDs to backplane) at necessary precision and yield, and scalable manufacturing processes and tools, etc. In our opinion, the technology that can address these challenges will see the early adoption and commercial success.

DSCC: You are going to present a proprietary µLED technology during the conference. For full color displays, which approach will be best: native emission or quantum dot color conversion?

Applied’s µLED front plane with UVLED dice + R/G/B quantum dot color conversion overcomes two key performance gaps of R/G/B dice direct emission approach. First, the low external quantum efficiency of Red µLEDs (especially as the die size approaches low single digit microns) that limits the current efficiency performance of the overall front plane. Applied’s approach improves the current efficiency by > 25%. Second, Applied’s approach maintains the color contrast at high viewing angles. In addition, fewer number of mass transfer steps and an innovative pixel architecture that reduces the complexity of sub-pixel repair, the Applied’s approach provides an inherent cost advantage.

The AR/VR Display Forum will take place on November 3-4. To watch the presentations from Applied Materials and other speakers, register at:

https://www.accelevents.com/e/...

All attendees will be able to watch recordings of the presentations for 30 days after the event.

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Written by

Dr. Guillaume Chansin

guillaume@displaysupplychain.com