Optimized microlens-array geometry for Hartmann–Shack wavefront sensor

Oliveira, Otávio Gomes de; Monteiro, Davies William de Lima; Costa, Rfo

doi:10.1016/j.optlaseng.2013.11.006

Cited by 16 publications

(6 citation statements)

References 8 publications

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“…The machining range was a circle with a radius of 1 mm. As shown in figure 5(b), a micro-lens array, which can be used in Shack-Hartmann wavefront sensors [23,24], etc, was also adopted as a designed surface profile. The profile of each lenslet was spherical.…”

Section: Layout Of Control Point Cloudmentioning

confidence: 99%

Tool path generation and optimization for freeform surface diamond turning based on an independently controlled fast tool servo

Sato

Yan

2022

Int. J. Extrem. Manuf.

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Diamond turning based on a fast tool servo (FTS) is widely used in freeform optics fabrication due to its high accuracy and machining efficiency. As a new trend, recently developed high-frequency and long-stroke FTS units are independently driven by a separate control system from the machine tool controller. However, the tool path generation strategy for the independently controlled FTS is far from complete. This study aims to establish methods for optimizing tool path for the independent control FTS to reduce form errors in a single step of machining. Different from the conventional integrated FTS control system, where control points are distributed in a spiral pattern, in this study, the tool path for the independent FTS controller is generated by a ring method and a mesh method, respectively. The machined surface profile is predicted by simulation and the parameters for the control point generation are optimized by minimizing the deviation between the predicted and the designed surfaces. To demonstrate the feasibility of the proposed tool path generation strategies, cutting tests of a two-dimensional sinewave and a micro-lens array were conducted and the results were compared. As a result, after tool path optimization, the peak-to-valley (P-V) form error of the machined surface was reduced from 429 nm to 56 nm for the two-dimensional sinewave by using the ring method, and from 191 nm to 103 nm for the micro-lens array by using the mesh method, respectively.

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Section: Layout Of Control Point Cloudmentioning

confidence: 99%

Tool path generation and optimization for freeform surface diamond turning based on an independently controlled fast tool servo

Sato

Yan

2022

Int. J. Extrem. Manuf.

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“…The computational test bench was designed, adapting a code in C language, originally developed in Delft -Netherlands by Gleb Vdovin and Davies W. de Lima Monteiro [9] and modified by Luciana P. Salles [10] and Otávio G. Oliveira [11]. The initial structure of the computational Test bench was constructed using the Hartmann-Shack technique of wavefront sensor.…”

Section: Computational Test Benchmentioning

confidence: 99%

“…The usage of Hartmann-Shack was done due to the fact that it presents a compact configuration that is robust to vibrations, because their components are generally secured together, has low cost, has a quick wavefront reconstruction since it uses relatively simple mathematical models to find the coefficients that describe the topology of a wavefront with modal method [9][10][11].…”

Section: Computational Test Benchmentioning

confidence: 99%

Computational test bench and flow chart for wavefront sensors

et al. 2014

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The wavefront reconstruction diagram has come to supply the need in literature of an ampler vision over the many methods and optronic devices used for the reconstruction of wavefronts and to show the existing interactions between those. A computational platform has been developed using the diagram's orientation for the taking of decision over the best technique and the photo sensible and electronic structures to be implemented. This work will be directed to an ophthalmological application in the development of an instrument of help for the diagnosis of optical aberrations of the human eye.KEY WORDS: Computational test bench, Flow Chart, wavefront sensors and ophthalmology.

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“…A few methods have been attempted for fabricating microlens arrays on silicon. Most of those methods are based on lithographic processes such as chemical etching [ 8 , 9 , 10 ] and laser assisted etching [ 4 , 5 ]. However, the available lens geometries are very limited and it is difficult to ensure the form accuracy of the lens arrays.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Hexagonal Microlens Arrays on Single-Crystal Silicon Using the Tool-Servo Driven Segment Turning Method

Mukaida

Yan

2017

Micromachines

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Single-crystal silicon microlens arrays are increasingly required in advanced infrared optics. In this study, the authors attempted to fabricate hexagonal microlens arrays, which offer high optical efficiency, on a single-crystal silicon wafer using diamond turning. A tool-servo driven segment turning method was proposed to reduce the dynamic error of the machine tool induced by lenslet edges during lens array cutting. From the results of both cutting experiments and theoretical analysis of the machine tool dynamic error, it was demonstrated that the segment turning method reduced significantly the dynamic errors and led to high form accuracy. As a result, sharp edges among the lenslets were generated precisely and microlens arrays with a form error of ~300 nm peak-to-valley and surface roughness of ~5 nmSa, which meets the requirements of infrared optical systems, were successfully fabricated. The subsurface damage, such as the amorphization of silicon, caused by machining was also reduced.

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Optimized microlens-array geometry for Hartmann–Shack wavefront sensor

Cited by 16 publications

References 8 publications

Tool path generation and optimization for freeform surface diamond turning based on an independently controlled fast tool servo

Tool path generation and optimization for freeform surface diamond turning based on an independently controlled fast tool servo

Computational test bench and flow chart for wavefront sensors

Fabrication of Hexagonal Microlens Arrays on Single-Crystal Silicon Using the Tool-Servo Driven Segment Turning Method

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