How Ion Beam Innovations Are Enhancing Waveguide Production for XR Applications

Augmented Reality (AR), Mixed Reality (MR), and Extended Reality (XR) have been on everyone's lips for some time. The first devices to hit the market were primarily used in the industrial segment. Applications were in online training, e-learning, and VR-supported maintenance. In fact, sales were still low due to the devices' bulky shape, heavy weight, and limited field of view (FOV).

However, the next generation of consumer devices is on the way. Those shall allow interaction between people and the digital universe—eyeglass-like, with an integrated mini-computer. The strategic goal: AR and MR devices as the next computing platform.

Among the most significant technological challenges to produce AR/MR devices is the fabrication of optical waveguide combiners. One challenge is producing waveguides that meet the specific requirements of human eyesight while keeping the headset compact and lightweight. High-index glasses and polymers are often used as waveguides for transparent near-eye displays. Therefore, the design and manufacturing of optical patterns, particularly surface relief gratings (SRG), used as in- and out-couplers of light into the waveguide, are critical to the performance of AR devices.

Within the coupling process, the light from the image source is transported by total internal reflection to the out-coupling grating. There, it is sent to the human eye with the aim of illuminating a large field of view (FOV) uniformly. This could be achieved by modulating the duty cycle, the slant angles, and the etching depths of the gratings. Furthermore, the slant angle adjustment allows the direction of the coupled light to be modified as specific diffraction orders increase or diminish in intensity.

The gratings can be etched directly into the waveguide by reactive ion beam etching (RIBE) or produced by nano-imprint lithography (NIL). Reactive ion beam trimming (RIBT) is especially suitable for NIL master stamp production because it adds additional degrees of freedom, like slant angle and etching depth variation, within a coupling element and over the whole sample.

This presentation shows how new developments in ion beam technology for AR applications enable flexible grating designs with excellent quality and how the shapes of slanted gratings can be further improved by precisely adjusting process parameters.

About the presenter
Marcel Demmler holds a degree in physical engineering. He began his professional career in research and development at a company specializing in ion-beam and plasma-processing technologies. In 2011, he transitioned into a commercial role, taking responsibility for sales activities in the United States and Japan. Since joining scia Systems in 2013 as sales director, Demmler has successfully built a global sales structure, expanding the company’s international presence.