Micromachining of assembled liquid crystal displays

Yeo, Song Huat; Tan, Ee-Lin

doi:10.1243/0954405011519385

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…Fabrication of nano and micron-scale features over a large area is required for various applications such as: metamaterial infrared absorber, 1,2 biomedical applications, 3,4 dielectric metamaterials for optical elements, 5 photonic crystals, 6,7 and microfluidic devices, 8,9 etc. Various techniques have been developed for the fabrication of micro-and nanostructures such as Focused Ion Beam (FIB), 10,11 Electron Beam lithography (EBL), 12–14 Laser Beam Machining (LBM), 15–19 Interference Lithography, 20,21 and Micro-lens array lithography using femtosecond laser. 22–24 However, the above-mentioned techniques have their benefits and limitations.…”

Section: Introductionmentioning

confidence: 99%

Large area fabrication of single micron features using two-photon polymerization with sub-nanosecond laser

Singh

Mishra

Ramkumar

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part B:

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Single micrometer-sized features were fabricated on ARN-4340 photoresist using a 3D additive technique of two-photon polymerization (TPP). An economic TPP setup capable of producing a large area was developed in the lab using a sub-nanosecond laser. The Photo-initiator (2, 4 Diethyl-9H-thioxanthen-9-one) with a large two-photon absorption cross-section was used to enhance the polymerization. It was theoretically determined that the dimensions of the polymerized features depend on the concentration of the photo-initiator. A novel image-based focusing technique was developed to achieve uniform microsized features on a large area. In the proposed TPP setup, the developed focusing technique was used to determine the area over the sample, which can be polymerized in one go. To demonstrate the capability of the developed setup, microstructures of about 1 µm width were fabricated over an area of 4 cm2. Further, the fabricated sample was used to develop a master mold of Polydimethylsiloxane, which can be used for a soft-lithography replication process. Also, the melt flow technique was explored to reduce the roughness in the fabricated structure. The multi-photon polymerization process using the sub-nanosecond laser is shown to be cost-effective and robust for large area microstructure fabrication.

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Section: Introductionmentioning

confidence: 99%

Large area fabrication of single micron features using two-photon polymerization with sub-nanosecond laser

Singh

Mishra

Ramkumar

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part B:

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“…Thus, some alternative techniques have been developed to fabricate microstructures with various materials and shapes [2][3][4][5]. A micro fabrication technique based on the femtosecond laser ablation has been proposed in the last two decades: the advantages of achievable structure resolutions, applicability for any solid materials, minimal thermal damage of the bulk material, and the absence of post-processing make femtosecond laser ablation more and more important in micro manufacturing [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Shape characteristics of microstructures in femtosecond laser multi-pulse ablation of metals

Wang

Mei

Jiang

et al. 2008

Proceedings of the Institution of Mechanical Engineers, Part B:

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In femtosecond laser multi-pulse ablation, the ablated surface and the fluence irradiated on this surface are ever changing. Thus, the simple summarization of single pulse ablation is not an accurate shape forecast method and the influence of beam spot change must be considered. In this paper, a new simulation method is proposed to forecast the microstructure shape, in which fluence distribution, ablation directions, and ablation rates of each pulse on the ablated surface are determined according to the spatial propagation characteristics of laser and two logarithmic ablation models. Further, the microstructure shape is obtained by accumulating the effects of all pulses. Three kinds of ablation -on-focus ablation, off-focus convergent beam ablation, and divergent beam ablation -are investigated using the proposed method. Simulation results show that the influence of beam spot change on microstructure shape is obvious. In convergent beam ablation, the structure has a sharp bottom, and the sidewall changes from concave to convex with the increase of pulses. In contrast, the structure obtained by divergent beam ablation has a much higher draft-angle and flatter bottom. Onfocus ablation can be regarded as parallel beam ablation when ablations proceed within the Rayleigh range and the profile keeps to the parabola function. In experiments, microstructures are machined with three kinds of ablation in typical metals, and it is proved that the proposed structure-developing model is a valid shape forecast method when vaporization is the main ablation mechanism.

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