SICウェーハがARメガネの虹の効果を排除するにはどうすればよいですか？
PAM-XIAMEN can offer optical grade SiC wafers for AR glasses, detailed specifications please consult [email protected]. SiC wafer, with its extraordinary refractive index (≥ 2.6), provides a physical level solution for eliminating rainbow stripe defects in optical waveguide structures. The essence of this phenomenon is that when ambient light passes through an AR waveguide, dispersion is caused by the difference in diffraction angles of different wavelengths of light by the grating, resulting in the decomposition of white light into rainbow spectra. The high refractive index property of SiC solves this problem from two dimensions:
SiC provides greater freedom for grating design due to its high refractive index characteristics, allowing for the use of smaller grating periods. When the grating period is reduced to the nanoscale, the diffraction angle of ambient light significantly increases, and its deviation range can exceed the range that the human eye can receive, thereby visually reducing the perception of interfering diffracted light.
Fig. 1 Optical simulation of SiC AR glasses
From the perspective of wave optics, the phase vector applied by the grating to the incident light is proportional to the wavelength and inversely proportional to the grating period. Therefore, the smaller the period, the greater the deflection angle of the diffracted light. For large angle incident light, a too small grating period can cause diffracted light to escape from the circular region maintained by the guided wave mode in the K-space distribution of the waveguide, thereby limiting the effective field of view. To achieve full-color transmission at large field of view angles in a single-chip system, it is necessary to avoid using grating periods that are too small.
The advantage of SiC materials in reducing the “rainbow effect” fundamentally stems from the design flexibility brought by their high refractive index. High refractive index structures can compress the effective wavelength of light waves, allowing for a significant reduction in grating period – for example, a grating with a period of 300nm can be achieved on SiC substrates, while traditional glass substrates typically require 500nm. This period compression effect can significantly reduce the dispersion angle difference of light with different wavelengths under fixed incident angle conditions. Experimental data shows that in the visible light range of 400-700 nm, the dispersion angle difference of SiC based gratings is reduced by about 40% compared to conventional materials. By rational design, stray light that produces rainbow effects can avoid the visible area of the human eye, effectively suppressing the occurrence of rainbow patterns.
In addition, studies have shown that integrating SiC substrate with an SiO2/TiO2/ITO multi-layer structures can effectively reduce the reflection of visible light on the surface of lenses, thereby improving the transmittance of lenses. On the one hand, the multi-layer structure can further reduce color deviation caused by light reflection, thereby indirectly reducing the rainbow effect; On the other hand, the multi-layer film structure can block blue light, which also helps to reduce the rainbow effect. Because blue light has a shorter wavelength, it is more prone to dispersion, leading to the rainbow effect.
The extremely high hardness and chemical stability of SiC substrate make it perfectly suitable for precision processes such as nanoimprinting and electron beam lithography, thereby achieving high-precision processing of submicron grating structures to solve the rainbow effect.
Whether you need SiC wafer for research or for industrial applications, please contact us email at [email protected] と [email protected].
参照：
Chen, B. , Li, C. , Li, X. , Zhao, D. , Cai, L. , & Du, K. , et al. (2024). Ultra-thin, ultra-light, rainbow-free ar glasses based on single-layer full-color sic diffrcative waveguide.