High-end Adhesives Fuel Innovation in XR Devices

Waveguides

Adhesives for enhanced waveguide performance

Optimize your AR experience with advanced polymer solutions

Waveguides are the heart of AR devices. Despite the prevalence of diffractive waveguides with imprinted surface relief gratings, the future dominance of diffractive, reflective, or holographic waveguides remains uncertain. What is undeniable, however, is that customized polymer solutions can enhance every waveguide combiner and often become indispensable in the manufacturing process.

For reflective waveguides, the right adhesive solution is crucial. These are created by joining individually coated flat glasses into large stacks. As segments are sliced from these stacks at specific angles, an optical-grade adhesive with a refractive index that closely matches the glass is vital for low haze and high transparency to bond these surfaces efficiently.

Moreover, adhesives must exhibit strong adhesion to coatings and glass, alongside superior mechanical properties to endure the stresses encountered during production. DELO's polymer range covers all these requirements.

Cover Glass Bonding

Waveguide stacking and cover glass bonding

Achieve precision and clarity in AR devices

The optical performance of a waveguide hinges on the maximum refractive index difference between glass and its surrounding media. A defined air gap is frequently necessary when stacking waveguides or placing a protective cover over the waveguide combiner, which is crucial for preserving diffractive waveguides' delicate grating structures.

We offer adhesives—either transparent or black—that cure in seconds, supported by spacer elements that maintain precise air gaps with unparalleled parallelism. With DELO materials, you can achieve adhesive beads as slim as 600 µm wide and as shallow as 50 µm high, facilitating an efficient and reproducible bonding and alignment process for maximum unit production per hour.

Edge Blackening

Edge blackening: Illuminate your AR experience

Cut reflections and perfect your optics

Eliminating unwanted reflections at the waveguide edge is crucial, or up to 10% of transmitted light could reflect back as it is the case for a waveguide substrate with a refractive index of 1.9, causing image distortion. DELO's edge blackening polymers offer the solution, with high optical density and a refractive index around 1.5. Even in layers as thin as 40 µm, these materials absorb most light and reduce parasitic reflections to approximately 1%, delivering optimal device performance.

Select from a variety of viscosities adapted to your desired layer thickness, with customized developments available by request. Additionally, capitalize on DELO's unique combination of materials and processes. Complementing our black materials, we provide high-end jet-dispensing solutions for reliable application on complex waveguide edges, ensuring swift processing for high UPH.

Depending on your optical density requirements, an energy-efficient UV-only curing process is also an option, minimizing energy consumption and the carbon footprint of production.