Pneumatically Actuated Thin Glass Microlens for On-Chip Multi-Magnification Observations

Yusufu Aishan,Yaxiaer Yalikun,Yo Tanaka

doi:10.3390/act9030073

Abstract

This paper presents a self-contained micro-optical system that is magnification-controlled by adjusting the positions of the microlens in the device via pneumatic air pressure. Unlike conventional dynamic microlenses made from a liquid or polydimethylsiloxane (PDMS) that change their shapes via external actuation, this system combines a fixed-curvature glass microlens, an inflatable PDMS layer, and the external pneumatic air pressure supply as an actuator. This device showed several advantages, including stable inflation, firm structure, and light weight; it achieved a larger displacement using the glass microlens structure than has been reported before. This fixed-curvature microlens was made from 120 µm-thick flat thin glass slides, and the system magnification was manipulated by the deflection of a 100 µm-thick PDMS layer to alter the distance from the microlens to the microfluidic channel. The system magnification power was proportional to the air pressure applied to the device, and with a 2.5 mbar air pressure supply, a 2.2X magnification was achieved. This optical system is ideal for combining with high resolving power microscopy for various short working distance observation tasks, and it is especially beneficial for various chip-based analyses.

Highlights

Optical systems at any scale require a focalizing mechanism [1] to produce clear and magnified images, as in cameras [2] or endoscopes [3]
We demonstrate a self-contained pneumatically actuated optical system that had its magnification controlled by the deflection of a 100 μm-thick PDMS layer
By regulating the external pneumatic air pressures to control the deflections of the thin elastic PDMS layer and the distance between the microlens and glass chip, an on-chip observation system providing various magnifications can be achieved

Summary

Introduction

Optical systems at any scale require a focalizing mechanism [1] to produce clear and magnified images, as in cameras [2] or endoscopes [3]. Microlenses are an important optical component that are often implemented in a miniaturized optical system for various purposes. These microlenses can roughly be categorized into two types. The first type is the fixed-curvature “solid” microlens [4] made from glass materials [5,6], and its magnification adjustment is achieved by changing the distance between one or more coupled lenses in the system [7]. Fixed-curvature glass microlenses produce relatively stable and good quality images compared to microlenses made from other materials, its fabricating limitations and actuating methods for moving those “solid” lenses in the applications remain just as problematic

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Discussion

Conclusion