The tl;dr version: SRG+ may be a very interesting technology that significantly improves AR waveguide displays’ efficiency, field of view, and form factor, with lower manufacturing costs and mass production potential. We’ll keep a track of it to see how it does in the wilds of actual product development.
SRG+ Breakthrough Features
SRG+ improves upon DigiLens’ existing volume Bragg gratings (VBG) technology, allowing the company to create enhanced surface relief gratings (SRG) that can be used in various applications such as waveguide displays.
DigiLens believes SRG+ is a breakthrough technology that overcomes the limitations of traditional surface relief gratings, such as those produced using nanoimprint lithography (NIL) techniques. The company touts the features of its technology: structure heights of multiple microns and aspect ratios surpassing 10:1 while maintaining cost-effective manufacturing methods. The absence of a bias layer in SRG+ enables reduced stray light and higher efficiency, leading to enhanced performance of lightguide eye-pieces. As a promising development in AR technology, DigiLens believes SRG+ holds great potential to deliver crucial attributes for the industry’s future.
| Feature/Benefit | Description | Explanation |
|---|---|---|
| Higher delta-n | Higher diffraction efficiency, wider angular response | Delta-n is the difference in refractive indices of a grating; higher delta-n improves efficiency and widens the viewing angle |
| S&P polarization | Ideal for microLED | S&P polarization refers to the separation of light into s (transverse electric) and p (transverse magnetic) polarized components, suitable for microLED displays |
| No bias layer | Wider angle response with high index glass | Bias layer in waveguides can limit angular response; its absence leads to wider angles and better performance |
| Tall gratings | Gratings several microns in height with high >10:1 aspect ratios | Tall gratings with high aspect ratios enable better light coupling and efficiency |
| Higher efficiency | Brighter/longer battery life | Improved energy efficiency results in brighter displays and longer battery life |
| Wider field of view | Improved AR experience | A wider field of view enhances the augmented reality experience by providing a more immersive view |
| Smaller footprint | Lighter/easier to style | A smaller device footprint allows for sleeker designs and improved wearability |
| Lower cost | Much lower cost of masters needed for manufacturing | Reduced manufacturing costs lead to more affordable devices |
| High-performance plastic | Safer/lighter weight | Utilizing high-performance plastics offers a lightweight and safer alternative to glass |
| Fast ramp-up to volume manufacturing | Simple manufacturing processes and fast cycle time for design optimization and waveguide manufacturing | Simplified and fast manufacturing processes allow for quicker time-to-market and easier optimization |
