The fabrication of high filling factor double side micro lens array with high alignment accuracy

Cheng, Yuan; Chen, Chun Chieh; Hsu, Wei Yao; Wang, Pei-Jen; Tsai, Din Ping

doi:10.1117/12.892444

Cited by 4 publications

(2 citation statements)

References 11 publications

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“…Inspired by biological compound eyes, researchers have conducted many studies on microlens array (MLA) which has been widely applied in many fields including fiber-optic sensing, beam shaping, and medical endoscopic lens. − The rapid development of augmented reality (AR) and virtual reality (VR) technologies has further extended the applications into multiple fields such as our daily life and military aerospace, − and the MLA is also regarded as an indispensable micro-optical device within this system. − For the applications in different environments, especially outdoors, MLA needs to be added with some additional properties. For example, water droplets may adhere to the MLA in outdoor or humid environments and result in obviously less optical performance, in terms of imaging and light convergence.…”

Section: Introductionmentioning

confidence: 99%

Superhydrophobic Multifocal Microlens Array with Depth-of-Field Detection for a Humid Environment

Cao,

Deng,

Wan

et al. 2023

ACS Omega

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Microlens array (MLA) has been widely applied in augmented reality and optical imaging. When used in a humid environment or medical endoscopy, MLA needs to be both superhydrophobic and multifocal. However, it is not easy to achieve both superhydrophobic and multifocal function by integrating superhydrophobic and multifocal structures on the same surface by means of a simple, efficient, and precise method. In this paper, the superhydrophobic multifocal MLA with superhydrophobic properties and multifocal functions is successfully designed for preparation based on a method of 3D lithography and soft lithography. The 3D lithography can further help the preparation of a multifocal MLA with varying apertures and a multistep superhydrophobic structure with a round dome. The superhydrophobic multifocal MLA with periods 50 and 120 μm has perfect superhydrophobic property. The water droplet can slide and bounce off the surface at a roll angle of less than 12.9° with both multifocal and integrated imaging function, as well as up to 397 μm depth-of-field (DOF) detection range; this greatly exceeds the conventional MLA. The perfect superhydrophobic and optical property can be achieved in an extremely humid environment. The superhydrophobic multifocal MLA proposed in this paper has a promising prospect for actual practices.

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Section: Introductionmentioning

confidence: 99%

Superhydrophobic Multifocal Microlens Array with Depth-of-Field Detection for a Humid Environment

Cao,

Deng,

Wan

et al. 2023

ACS Omega

View full text Add to dashboard Cite

show abstract

“…Based on studies of insect compound eyes, microlens arrays (MLAs) have found applications in many areas, such as fiber coupling, sensing, and beam shaping. − Due to the rapid development of augmented reality (AR) and virtual reality (VR) technologies, which have applications ranging from daily civil to military applications, − MLAs are considered indispensable micro-optical devices for virtual imaging. − For applications in various environments, especially in outdoor environments, composite functions are required for MLAs. For instance, in a humid environment, water droplets could adhere to the MLA surface, which would significantly hinder the imaging performance of the MLA.…”

Section: Introductionmentioning

confidence: 99%

Flexible Superhydrophobic Microlens Arrays for Humid Outdoor Environment Applications

Luan

Zhang

et al. 2022

ACS Appl. Mater. Interfaces

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A microlens array (MLA) is an essential optical imaging device in the applications of augmented and virtual realities. The imaging of MLA would become blurry in a humid outdoor atmosphere. While the incorporation of superhydrophobicity to MLA would prevent the adhesion of droplets, the complex structure and the multiple fabrication process reduce the capability of optical imaging of MLA. Herein, a flexible superhydrophobic MLA with good optical imaging capability is successfully fabricated by the combination of 3D direct laser writing (DLW) and soft lithography. 3D DLW allows the fabrication of MLA with a hierarchical pillar array (h-MLA) in one step, which ensures good optical properties of the resulting polydimethylsiloxane (PDMS) h-MLA. The resulting h-MLAs with pitches ranging between 50 and 100 μm are superhydrophobic from which water droplets slide away at a sliding angle smaller than 15.6°and bounce off from the surface. Meanwhile, the hierarchical pillar array has a limited impact on the imaging capability and the field of view of h-MLA. With an optimized pitch of 60 μm, h-MLA has a transparency as good as MLA. Moreover, PDMS h-MLA retains excellent optical and superhydrophobic properties when bent and in an extremely humid environment. We believe that the proposed h-MLA could find applications in outdoor environments.

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Alignment error modeling and control of a double-sided microlens array during precision glass molding

Zeng,

Zhou,

et al. 2024

Microsyst Nanoeng

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Double-sided microlens arrays (DSMLAs) include combinations of two single-sided MLAs to overcome positioning errors and greatly improve light transmissivity compared to other types of lenses. Precision glass molding (PGM) is used to fabricate DSMLAs, but controlling alignment errors during this process is challenging. In this paper, a mold assembly was manufactured with a novel combination of materials to improve the alignment accuracy of mold cores during PGM by using the nonlinear thermal expansion characteristics of the various materials to improve the DSMLA alignment accuracy. By establishing a mathematical model of the DSMLA alignment error and a thermal expansion model of the mold-sleeve pair, the relationship between the maximum alignment error of the DSMLA and the mold-sleeve gap was determined. This research provides a method to optimize the mold-sleeve gap and minimize the alignment error of the DSMLA. The measured DSMLA alignment error was 10.56 μm, which is similar to the predicted maximum alignment error. Optical measurements showed that the uniformity of the homogenized beam spot was 97.81%, and the effective homogeneous area accounted for 91.66% of the total area. This proposed method provides a novel strategy to improve the performance of DSMLAs.

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The fabrication of high filling factor double side micro lens array with high alignment accuracy

Cited by 4 publications

References 11 publications

Superhydrophobic Multifocal Microlens Array with Depth-of-Field Detection for a Humid Environment

Superhydrophobic Multifocal Microlens Array with Depth-of-Field Detection for a Humid Environment

Flexible Superhydrophobic Microlens Arrays for Humid Outdoor Environment Applications

Alignment error modeling and control of a double-sided microlens array during precision glass molding

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