Saphlux S1 RDK – Technical Analysis

I’ve had the Saphlux S1 RDK sitting on my desk for a little while now, and it was finally time to tear it apart and take a closer look at what is inside. Unlike most of the AI-focused smart glasses we have reviewed recently, this is a reference design kit rather than a finished consumer product — which means some expected rough edges for software & hardware choices that are not the display. We’re starting to see this more and more with display companies pushing into some part of the consumer smartglass segment (MICROOLED with Engo, but a lot of uLED companies are following similar paths)

The S1 RDK is built around a monochrome green microLED display, a diffractive waveguide, integrated audio, and a fairly conventional glasses-shaped mechanical package that is very reminiscent of the Alibaba Quark S1 Glasses. There’s plenty of additional data shared in the video, so here we will focus on a few of the measurements that stood out during testing.

Disclosure: I am a technical advisor for Saphlux, but the opinions expressed and data collected in this video are entirely my own.

The microLED spectrum is the first interesting result. The Saphlux panel has a green emission peak centered at approximately 515 nm, compared with approximately 523 nm for the Jade Bird Display panel measured in most other smartglasses using mono green panels. Both are narrow-band inorganic LED emitters, but the wavelength difference is large enough that the Saphlux panel appears noticeably closer to a saturated emerald green.

This does not automatically make one panel “better” than the other — display color is ultimately a product-design choice — but it is a good reminder that monochrome green microLED panels are not all interchangeable. The exact wavelength affects perceived color, luminous efficiency, optical-system performance, and potentially the readability of the final UI.

The optical path is a fairly standard diffractive-waveguide structure. Starting with the microLED panel (1), the emitted light passes through an aspheric field lens (2) and enters the waveguide through the input grating (3). The image propagates through the waveguide using total internal reflection before reaching the exit grating (4), which expands the eyebox and redirects the image toward the user.

As always with waveguides, not all of the injected light makes it to the eye. Most of the light continues toward the world side or is lost outside the intended eyebox. That said, starting with a very bright…