Roll-to-Plate (R2P) large-area Nanoimprint Lithography (NIL) is a leading technology to replicate complex textures onto various substrate materials. It combines the accuracy of UV imprinting with large-area display manufacturing methods. This is a significantly cost-effective manner to perform micro and nano surface patterning for a plurality of display optics applications, including emerging technologies, such as Augmented Reality (AR) waveguides. Even though NIL technology is advancing to comply with the strict quality requirements of waveguide manufacturing, many challenges still remain. Hereby, we address different aspects that need to be considered to make R2P-NIL a viable mass manufacturing method for AR optics, focusing on scalability and quality. We discuss the potential for scalable waveguide manufacturing, through waveguide upscaling for large-area NIL (Gen5 size, 1100 mm x 1300 mm), in combination with the usage of square high refractive index glass substrates (in contrast to the usual round wafers). By making optimal use of this combination, we demonstrate that 480 waveguides can be manufactured in one imprint cycle. Additionally, of equal importance to scalability, high waveguide quality is achieved through the use of high refractive index materials, maintaining of imprint fidelity, and control of the residual layer thickness and its variation. We show that, using the R2P-NIL technology of Morphotonics to replicate AR waveguides, imprint fidelity of binary, blazed and slanted gratings are retained over repeating imprint cycles.
Amidst the mixed news surrounding the feasibility of Augmented Reality (AR) smart glasses, the demand for commercially viable mass production of industry-standard optical waveguide combiners remains unwavering. Over the past two years, our consortium of companies has proposed a cost-effective and scalable manufacturing process for Surface Relief Grating (SRG) based waveguides, offering a comprehensive path from concept to fabrication through large-area nanoimprinting. This approach has garnered significant interest from both customers and partners associated with the participating companies. Our aim is to push beyond the established limits of large-area nanoimprinting. In this work we address the obstacles and latest advancements in maintaining imprint quality, fidelity and uniformity during large-area nanoimprinting. We demonstrate various building blocks that are crucial to manufacture high quality and cost-effective AR waveguides, such as the replication of slanted gratings and the possibility of low residual layer thickness using large-area nanoimprint lithography. We employ high refractive index materials, such as resin and glass (1.8, 1.9 and 2.0), and also explore a lighter and flatter version of the RealView 1.9 glass. Our primary objective is to demonstrate that large-area nanoimprinting not only presents itself as a novel method for high-volume manufacturing of SRG waveguides but also enables the production of challenging optics for AR smart glasses.
Nanoimprinting of surface-relief grating-based waveguides has the potential to produce one of the industry-leading augmented reality (AR) smart glasses, but there are still many challenges in the design, scaling, and reproducibility of these imprinted waveguides. A promising path toward mass manufacturing of optical waveguide combiners is via large-area nanoimprinting. Here, we present the complete value chain with partners involved throughout the process: from design, mastering, and materials to imprinting and metrology, to prove that this method improves not only the manufacturing throughput but also the waveguide quality. We demonstrate that the replication and image quality are true to the intended design using large area, high refractive index (n = 1.9), square (300 mm × 300 mm) glass substrates with high-refractive index resins (n = 1.9). This is shown to be valid for over 100 replications and for large area nanoimprinting (Gen5, 1100 mm × 1300 mm). Our goal is to demonstrate a viable path toward high-volume and low-cost manufacturing of AR waveguides based on surface relief gratings.
Nanoimprinting of surface-relief grating-based waveguides has the potential to result in the best performing Augmented Reality (AR) smart glasses, but there are still many challenges in the design, scaling, and reproducibility of these imprinted waveguides. We presented a promising path toward mass manufacturing of optical waveguide combiners via large-area nanoimprinting at SPIE AR/VR/MR 2022. This alternative route for manufacturing surface-relief gratings on a larger area generated much interest. This follow-up paper presents a further optimized design based on the lessons learned from the previous paper, with a particular focus on quality. The complete value chain with partners is involved throughout the process of this iterative update: from design, mastering, and materials to imprinting and metrology, to prove that this method improves not only the manufacturing throughput but also the waveguide quality. We demonstrate that both the replication and image quality is true to the intended design using large area, high refractive index (1.9 RI), square (300 x 300mm) glass substrates with high refractive index resins (1.9 RI). Our objective is to further establish this new approach towards high-volume and low-cost manufacturing of waveguides based on surface relief gratings as a viable path forward for enabling the Metaverse.
One of the primary cost-drivers of AR glasses is the optical waveguide. Yet, it is challenging to maintain the quality of the complex waveguide manufacturing in higher volumes. Large area Roll-to-Plate (R2P) nanoimprinting is a viable route forward, combining the UV imprint accuracies with the large-area display manufacturing method. Therefore, it is the proposed solution to manufacture optical waveguides for AR glasses in the consumer market.
At Morphotonics, we strive to build the foundation for a future where large-area R2P nanoimprinting produces AR optical waveguide combiners in typical high quantity display volumes. In this talk, we will address the upscaling process required for AR optics manufacturing via large-area nanoimprinting as well as the current status in terms of performance, materials, and manufacturability. Additionally, we will highlight the exemplary work recently undertaken with our industry partners to validate the entire value chain from design to mastering to replication on panel-level nanoimprint equipment using rectangular high refractive index glass substrates and high refractive index resins.
A promising path towards consumer electronics-ready manufacturing of optical waveguide combiners is via large-area nanoimprinted surface relief gratings on high index glass substrates. Presently, this is realized through equipment and substrates based on wafer format (up to 12-inch). In this work, we present a way to produce waveguides with surface relief gratings utilizing the entire value chain from design to mastering to replication on panel-level nanoimprint equipment using rectangular high refractive index glass substrates and high refractive index resins. This is demonstrated on a greater than Gen 3 panel size (550 mm x 650 mm). The fabricated waveguides are optically tested to validate the design and the value chain. We demonstrate that the quality of the large area imprints is similar to present wafer-level imprints. Thus, we introduce a new approach towards high volume and low-cost manufacturing of waveguides based on surface relief gratings.
If AR smart glasses are to become the ‘next big thing’ and commonplace, their optics must be easier and more affordable to manufacture. Though optics may only be part of a total AR system, it plays a vital role as the window to the world for its wearer. The industry has already set the technical criterion for an acceptable AR optics solution in terms of efficiency and form factor. But the commercial viability of this complex optical product is still challenging. The solution to cost-effectively produce the waveguide combiners, is to switch the manufacturing mindset from a purely semiconductor-based one to one rooted in the realities and learnings of the display industry. We at Morphotonics strive to build the foundation for a future when large-area nanoimprinting can produce AR optical waveguide combiners in display volumes. In this talk, we will address the upscaling process of AR optics manufacturing via large-area nanoimprinting as well as the remaining challenges in terms of performance, materials, and manufacturability. Additionally, we will highlight the exemplary work recently undertaken with our industry partners to validate the entire value chain from design to mastering to replication on panel-level nanoimprint equipment using rectangular high refractive index glass substrates and high refractive index resins.
The interest for nanoimprint lithography (NIL) as enabling technology for applications in the field of photonics, solar, lighting and displays is growing. The quality, flexibility in design, the relative ease and competitive costs at which surfaces can be patterned makes NIL a groundbreaking technology. While the added value of imprinted light management crystallizes, the need for high-volume NIL production methods becomes more urgent. The Roll-to-Plate (R2P) imprint technology can enable mass volume production, having the opportunity for large area imprinting, manufacturing higher numbers of smaller products in a single imprint step. In this presentation the replication process and quality of the Morphotonics GEN5 R2P imprint equipment will be discussed.
In a waveguide-type display for augmented reality, the image is injected in the waveguide and extracted in front of the eye appearing superimposed on the real world scene. An elegant and compact way of coupling these images in and out is by using blazed gratings, which can achieve high diffraction efficiencies, thereby reducing stray light and decreasing the required power levels. This study investigates the fabrication of blazed gratings with grayscale electron beam lithography and the subsequent replication of the realized 3D grating structures in a polymer material with ultraviolet nanoimprint lithography. As such, diffractive elements are realized on a waveguide sheet, with very good control over the dimensions and the profile of the printed features. Blazed gratings are designed for green light (λ= 543 nm) and a diffraction angle of 43°. Making use of a PMMA resist and by carefully optimizing the electron-beam parameters, electron dose distributions and development step, blazed gratings with a pitch of 508 nm and a fill factor of 0.66 are achieved. Finally, a master is realized with two blazed gratings, 3 cm apart, which are replicated using ultraviolet nanoimprint lithography onto a waveguide sheet. The in- and outcoupling of an image through these two blazed gratings is shown, appearing sharp and non-distorted in the environment, and a throughput efficiency of 17.4% is confirmed.
We developed a groove-only rewritable disc for the DVR system with a blue laser diode (wavelength 405 nm). Using standard detection electronics we obtained a capacity of 23.3 GB. Higher capacities are possible with advanced detection methods. Wide system margins are obtained at 320 nm track pitch and 80 nm channel-bit length. Fast-growth materials are used for the active layer. No thermal cross-write effect is present in the central track when neighboring tracks are repeatedly rewritten.
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