Geometric Waveguides and Optical Engines

Because light is reflected and steered toward the eye rather than diffracted in many directions, only a small fraction leaks outward, so bystanders see little to no readable image in the lens. This "privacy by design" contrasts with diffractive waveguides, where strong external eye glow and visible content are common complaints in social and professional environments.

Lumus optical engines are display agnostic: they can pair with LCOS, microOLED, laser scanned, or microLED projectors, if the optics collimate light into the waveguide entrance aperture.

The high efficiency of the reflective architecture is particularly attractive for microOLED and microLED, where driving the emitters at lower peak brightness extends lifetime and reduces power draw.

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Because they are thin, transparent, and efficient, Lumus type waveguides enable glasses like form factors with large FOV (50–70° in current designs) while still delivering daylight capable brightness and long battery life.

This combination of ergonomics and visual performance is difficult to achieve with bulkier combiner optics or less efficient diffractive approaches, making geometric waveguides a key enabler for truly wearable AR.

Reflective waveguides deliver much higher optical efficiency, which translates into significantly lower power consumption and the ability to stay visible even in bright environments without extreme projector nits.

They also provide superior color uniformity (true whites, minimal rainbow artifacts) and far lower outward "eye glow," improving both visual comfort and privacy compared with typical diffractive stacks.

A miniature projector (LCOS, microOLED, laser, or microLED) creates a virtual image and injects it into the waveguide entrance; inside, arrays of partially reflective mirrors perform two dimensional pupil expansion, so the same image is replicated across a wide eyebox. As light exits through the mirror array toward the eye, the user sees a floating image overlaid on the real scene, with uniform brightness and color across the field of view.

1. Geometric waveguides use principles of classical geometry and reflection to manipulate light. Light is guided by Total Internal Reflection (TIR) and coupled out by an array of microscopic, semi-reflective mirrors (or beam splitters) embedded inside the glass substrate. Manufacturing involves thin-film coating, polishing, and bonding/lamination processes (similar to traditional lens making). No exotic materials are necessary. The outcoupling element are partially reflective mirrors/coatings.

2. Diffractive waveguides use principles of diffraction to manipulate light, relying on tiny, nano-scale structures etched onto or embedded in the glass surface. Light is
guided and coupled out by nanoscopic periodic structures called gratings (either Surface Relief Gratings or Volume Holographic Gratings), which bend and split the light. Manufacturing involves advanced lithography or nanoimprint processes. The outcoupling elements are Nano-gratings (periodic structures).

Read more on Geometric Waveguides here.

The angles of confinement, the coupler geometry, and the physical thickness/shape of the guide.

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Yes - several consumer and enterprise AR devices rely on geometric or reflective waveguides. Lumus’ geometric waveguides are available in Meta’s commercial AR glasses.

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Yes. Since they are not wavelength-selective, they are naturally broadband. However, brightness and uniformity can still vary across RGB.

Yes. Typically, they are 5X-10X more efficient than diffractive alternatives.