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Controllable long focal length microlens based on thermal expansion
Applied Optics
|May 24, 2018
Summary
Researchers developed a new method to create microlens arrays with extended focal lengths using two materials with differing thermal expansion. This thermal expansion process allows controlled focal length adjustment by altering processing temperatures.
Area of Science:
- Optics and Photonics
- Materials Science
Background:
- Microlens arrays are crucial optical components.
- Achieving long focal lengths in microlenses can be challenging with conventional methods.
Purpose of the Study:
- To develop a novel method for fabricating microlens arrays with adjustable long focal lengths.
- To investigate the thermal expansion process for controlled microlens deformation.
Main Methods:
- Fabrication of microlenses using two materials with significantly different coefficients of thermal expansion.
- Controlled heating and analysis of the resulting surface deformation and focal length changes.
- Measurement of focal length and geometry dependence on temperature.
Main Results:
- Successful fabrication of cylindrical polymeric microlens arrays.
- Demonstrated control over focal length by adjusting processing temperature.
- Achieved a 38.2% increase in focal length within a 20°C to 50°C temperature range.
- Obtained a maximum focal length of 6.6 mm for a 240 μm linewidth microlens.
Conclusions:
- The novel thermal expansion method effectively enables the fabrication of microlens arrays with tunable long focal lengths.
- The study validates the formation mechanism and controllability of the process.
- This technique offers a promising approach for advanced optical component design.
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