Silicon Carbide: A New Material To Break Through The Display Bottleneck of AR Glasses

As the integration of artificial intelligence and augmented reality (AR) technology becomes increasingly close, AR glasses are seen as an important future smart terminal.However, in the pursuit of a broader field of view, a thinner form factor, and longer battery life, traditional optical materials have encountered a core bottleneck. In recent years, a material already widely used in the new energy sector—silicon carbide—has brought a new solution to the full-color display challenges of AR glasses.

The Display Bottleneck of AR Glasses: Why New Materials Are Needed

The current mainstream optical solution for AR glasses is diffractive waveguide technology, which allows lenses to be thinner and offer a larger field of view (FOV). However, the substrate materials this technology relies on, whether glass or resin, have significant limitations: firstly, a limited field of view due to the low refractive index of traditional materials; secondly, rainbow artifact interference, where dispersion causes rainbow-like stray light as light passes through the grating structure; and thirdly, a thermal dissipation challenge, as traditional materials' poor conductivity necessitates bulky additional cooling for high-brightness displays and processors, increasing device weight and complexity.

Silicon Carbide: Advantages of High Refractive Index and High Thermal Conductivity

The reason silicon carbide has come into the view of the AR industry lies in its two outstanding physical properties: a high refractive index and high thermal conductivity.

1. Achieving a Broader Field of View
The higher the refractive index of a material, the larger the field of view a waveguide can achieve. Ordinary glass has a refractive index of about 1.5, while silicon carbide can reach over 2.6. This means that using a single-layer silicon carbide lens could potentially achieve a field of view exceeding 80 degrees, far surpassing the approximately 40-degree level of traditional glass stacking solutions and enabling a more immersive visual experience.

2. Effectively Suppressing Rainbow Artifacts
The root cause of rainbow artifacts is dispersion. The high refractive index of silicon carbide compresses the effective wavelength of light within the material, thereby reducing the required grating period and increasing the diffraction angle of ambient light beyond the observable range of the human eye. This fundamentally mitigates or eliminates rainbow artifact interference.

3. Excellent Thermal Performance
The thermal conductivity of silicon carbide is as high as approximately 490W/(m·K), while that of glass is only about 1W/(m·K). This exceptional thermal conductivity allows for the rapid and even conduction and dissipation of heat generated by the optical engine and processor, preventing performance degradation due to localized overheating. This enables AR glasses to support higher brightness displays (e.g., 5000 nits peak brightness) and allows the heat dissipation function to be integrated into the lens itself, simplifying structural design and freeing up space for integrating more sensors.

Technological Implementation and Industry Progress

Applying silicon carbide to optical waveguides is not a simple transplant. It requires innovation across the entire chain, from material preparation and chip design to manufacturing processes.

In terms of manufacturing, research institutions have developed nanoimprint lithography and stripping processes suitable for mass production, which can efficiently transfer fine grating patterns onto silicon carbide wafers. Furthermore, by introducing ultra-thin packaging processes that encapsulate the waveguide with a sandwich structure of hard coating and anti-reflection coating, light transmittance can be improved while protecting its microstructure. A monolithic silicon carbide waveguide manufactured using such advanced processes can already achieve an ultra-thin and light form factor with a thickness of only 0.75 mm and a weight of less than 4 grams, representing a significant breakthrough.

Collaboration across the upstream and downstream of the industrial chain is also crucial. Enterprises and technical teams from all segments—from substrate materials and wafer manufacturing to waveguide design and complete AR devices—are strengthening cooperation to jointly promote the alignment of design requirements with material properties. The goal is to tackle the main obstacle currently limiting the large-scale application of silicon carbide: cost, while improving performance.

To conclude, silicon carbide addresses the fundamental limitations of AR displays through its superior refractive index and thermal conductivity. Its path to widespread use hinges on overcoming cost barriers through mature processes and stronger industry chains. Looking ahead, as the vision for AR glasses expands beyond displays to full-fledged AI-powered spatial computers, silicon carbide will be more than just a better material—it will be a foundational enabler for the entire system, supporting the integration of advanced sensing and computing in ever-thinner form factors.