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We design the HUD’s package dimensions is 12 cm x 12 cm x 9 cm. We want to use the MLA to reduce the volume by virtual image stitching. We proposed a HUD including micro-projectors, rear-projection screen, microlens array (MLA) and the light source is 28 mm x 14 mm realized a 200 mm x 100 mm image in 3 meters from drivers. Another problem, the volume of HUD is too large. Although there have been some HUD systems in commercial product already, their images are too small to show assistance information. Head-up Display (HUD) is a safety feature for automobile drivers. This will be useful for the optical zoom system or focus-tunable lens applications. From measuring the interference rings, the optical power range is from 47.28 to 331 diopter. Finally we assemble it with ITO glass and inkjet liquid crystal. After the transparent conducted polymer, PEDOT:PSS, is spin-coated on the microlens arrays surface, we flatten it by NOA65. Then we start replication process with polydimethylsiloxane (PDMS) to transfer microlens array form silicon to glass substrate. We first fabricate microlens array on silicon substrate by hydrophilic confinement, which between hydrophilicity of silicon substrate and hydrophobicity of SU-8, and inkjet printing process.
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These microlens have same diameter and height about 300 μm and 85 μm. The dimension of the glass is 1.5 cm x 1.5 cm x 0.7 mm which has 7 concave microlens on the top surface. The simulation results show that a GRIN lens model can well match with the theoretical focal length of liquid crystal lens.
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We used Zemax® to simulate the liquid crystal lens as a Gradient-index (GRIN) lens. After the spherical-shaped electrode is done, we assemble it with ITO glass to form a liquid crystal cell. Inkjet-printing, hydrophilic confinement, self-assemble and replication process is used to form the convex microlens array on glass. In this paper, a new approach to fabricate a liquid crystal (LC) microlens array with spherical-shaped electrode is demonstrated, which can create the inhomogeneous electric field. By using the 3D printer, we can make a model of lens array to achieve our design. The system can provide a large field of view about 150 degrees which is much wider than the commercial products.
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The panel size is designed to be 4 inch which is the scale of eyeglass. The thickness from the panel to the last surface of lens group is less than 25mm. In order to simulate the image stitching, we also build an eye model. Each partial image passes through each channel and stitches together on the retina to reconstruct a complete image. Each channel of an array of multiple optical system transfers only a part of the field of view. The optical axes of different channels are tilted to each other in order to reduce the optical system volume and transmit a wide field of view. Both of them have the same curvature and the radiuses of the lenses in the arrays are optimized to focus rays on the retina. The system consists of two curved structure lens arrays with different pitches. In this paper, we propose a multi-channel imaging system which combines the principles of an insect’s compound eye and optical cluster eye. We have achieved a large FOV of 40 degree with a 3 mm thick waveguide. In other words, the optical rays with different incident angles are reflected at corresponding coating surfaces. Each coating possess a critical angle that filters and reflects the optical rays that have a matching incident angle. Our triple coating surface allows more flexibility on the reflections of optical rays. Traditionally, the FOV relies on the size of the single couple out surface as the single surface determines all wave reflections. To improve the drawbacks above, we propose a triple coating surface waveguide that is thinner than the traditional designs of the AR HMD devices, We separate our waveguide into two parts: (1) The free-form surface collimator based on the n0n-pupil forming system, constructed by four high order term extended polynomial surfaces, (2) The triple coating surface directly attached at the end of the waveguide. However, there are still two major challenges for AR: (1) The inconvenience brought by the bulkiness of AR head mounted display (HMD) devices (2) The limited magnitude of the field of view (FOV). Overlapping virtual images onto the external view, AR has contributed to applications, such as education, medical surgery, engineering, entertainment, image-guided navigation and even military. Recently, with its blooming developments over decades, AR has established distinguishing features that makes it widely applicable among various fields. This article present a design method- a triple coating surface waveguide for augmented reality (AR).