NTT-AT and EVG Demonstrate the Feasibility of Applying High-Refractive-Index Resins to AR Optical Devices Using the SmartNIL® Process

NTT ADVANCED TECHNOLOGY CORPORATION (NTT-AT; headquarters: Shinjuku-ku, Tokyo; President and CEO: Tadashi Ito) and EV Group (EVG; headquarters: Austria), a leading provider of innovative process solutions and expertise serving leading-edge and future semiconductor designs and chip integration schemes, have jointly verified the compatibility of NTT-AT’s UV-curable high-refractive-index resins with EVG’s proprietary SmartNIL^® process technology and evaluated the feasibility of manufacturing waveguides for AR optical devices.

The joint evaluation confirmed high pattern fidelity, repeatable imprinting performance, and environmental resistance required for production applications. The results demonstrate the effectiveness of combining NTT-AT’s NH700 Series high-refractive-index resins with EVG’s SmartNIL^® technology for manufacturing AR optical devices.
The results will be presented at the 27th China International Optoelectronic Exposition (CIOE 2026), and a white paper summarizing the evaluation will be published.

1. Background
As demand continues to grow for next-generation wearable displays such as AR glasses, the industry is increasingly focused on achieving both lightweight designs and superior image quality. AR waveguides rely on micro-optical structures, including diffraction gratings and meta-optical elements, making scalable manufacturing technologies essential. Nanoimprint lithography (NIL) has emerged as a promising approach for producing these structures with high precision and cost efficiency. To enable commercial-scale deployment, however, high-accuracy nanoimprint systems must be paired with compatible high-refractive-index materials.

2. Evaluation Overview and Results
In this joint evaluation, NTT-AT used NH762, one of the materials in its NH700 Series of high-refractive-index resins, to verify compatibility with EVG’s SmartNIL^® technology and EVG^® NIL UV/AS5 working stamp material. The results confirmed the high pattern fidelity and manufacturing suitability required for AR waveguides. Environmental resistance testing was also conducted on samples imprinted with NH762, confirming only minimal changes in pattern geometry before and after testing.

The evaluation confirmed high-precision replication of 350 nm line-and-space structures, as well as successful replication of 45°slanted gratings and meta-optical elements with minimum feature sizes of 65 nm, without defects or deformation. In addition, a consecutive 25-imprint test using EVG^® NIL UV/AS5 limited the change in imprinted pattern height to approximately 2.2%, confirming dimensional stability and release performance that are important for production applications.

Furthermore, changes in the imprinted pattern structures remained extremely small after damp-heat and light-exposure testing, confirming the high environmental resistance required for AR optical devices. These results demonstrate that NH762 offers strong practical potential as an AR waveguide material combining a high refractive index, high transparency, and environmental durability.

Specifications of the NH700 Series High-Refractive-Index Resins:

3. Customer Benefits
Developing AR optical devices often requires considerable effort and time for material evaluation, reliability testing, and verification of manufacturing compatibility. Through this work, a nanoimprint material-and-process solution whose compatibility has been evaluated in advance can now be made available to customers. This is expected to help AR optical device manufacturers significantly shorten the time required for material selection and early-stage process development, while facilitating a smoother transition to production-scale manufacturing.

4. White Paper Availability
A white paper summarizing the results of this evaluation will be available on the website below.
https://keytech.ntt-at.com/en/adhesive/high-n.html

5. Future Development
In addition to NH762, the high-refractive-index resin jointly evaluated in this study, NTT-AT and EVG plan to evaluate the imprinting performance of other materials in the NH700 Series using the same nanoimprint equipment. The companies will continue development and evaluation with a view to applications not only in AR optical devices, but also in next-generation meta-optical elements, LiDAR, and sensing devices.

6. Exhibition InformationExhibition: The 27th China International Optoelectronic Exposition (CIOE 2026)
Dates: September 9 (Wed.)–11 (Fri.), 2026
Venue: Shenzhen World Exhibition & Convention Center
Event information: https://www.cioe.cn/CIOE/LP/index-jp.html

■ About NTT ADVANCED TECHNOLOGY CORPORATION (NTT-AT)

Since its establishment in 1976, NTT ADVANCED TECHNOLOGY CORPORATION (NTT-AT) has served as a technology-driven company within the NTT Group, leveraging advanced technologies developed by NTT laboratories as well as leading-edge technologies from around the world. By integrating these technologies, NTT-AT continuously delivers value to customers by addressing a wide range of technical and business challenges.
NTT-AT operates its business through four core domains: Applications, Materials & Nanotechnology, Social Platforms, and Total Solutions.
Website: NTT-AT Corporate Website

■ About EV Group (EVG)
EV Group (EVG) provides innovative process solutions and expertise that serve leading-edge and future semiconductor designs and chip integration schemes. The company’s vision of being the first in exploring new techniques and supporting next-generation applications of micro- and nanofabrication technologies enables customers to successfully commercialize new product ideas. EVG’s high-volume-manufacturing-ready products, which include wafer bonding, lithography, thin-wafer processing and metrology equipment, enable advances in semiconductor front-end scaling, 3D integration and advanced packaging, as well as in other electronics and photonics applications.
Website: EV Group Corporate Website


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