Papers by Author: Cheng Huan Chen

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Authors: Cheng Huan Chen, Po Chou Chen, Chin Ju Hsu, Chia Jen Ting
Abstract: A diffractive laser beam shaper has been proposed as a lossless approach to transfer a Gaussian laser beam into a thin line beam with a uniform distribution along the line direction for scanning material processing or illumination application. With the consideration for the feasibility of fabrication, the optical performance of the diffractive beam shaper with its surface relief quantized at different levels has been analyzed with scalar diffraction theory, which shows that an 8 level solution is sufficient for keeping the uniformity in the line direction while the focusing function in the orthogonal dimension needs to be performed by an extra cylindrical lens.
Authors: Cheng Huan Chen, Chien Chuan Chen, Po Hung Yao
Abstract: Laser light source is a potential illumination light source for non-emissive display applications, especially for liquid crystal projection displays, due to its requirement of low etendue source and highly polarized light. In order to make a conversion from a circular Gaussian beam profile to a rectangular uniform distribution, a microlens array has been proposed as a homogenizer. The analytical and experimental results show that the microlens array with a pitch of 100um under laser beam illumination works as a diffractive element, and a promising uniformity can be obtained with a stack of two microlens array.
Authors: Pei Lum Tso, Cheng Huan Chen
Abstract: Sintered polycrystalline diamond (PCD) compacts are normally used for cutting tools, drill bits and wire dies. A novel application of PCD has been developed to use its entire surface carved to create different patterns which are triangle or square shape loaded with leveled millers that can shave brittle materials in ductile mode. Due to numerous cutting edges formed on the same level of PCD tools, which can be used to thin the wafer surface to achieve both flatness and smoothness of the industrial requirements. SEM has been used to observe the surface and subsurface of the thinned wafer surface. The critical depth of cut between ductile and brittle cutting mode is close to 2 µm in this thinning operation. The damaged layers of machined surface have been observed and studied in this paper.
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