Simulation and measurement of optical aberrations of injection molded progressive addition lenses

Raasch, Thomas W.; Yi, Allen Y.

doi:10.1364/ao.52.006022

Cited by 20 publications

(9 citation statements)

References 15 publications

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“…simulation, [9][10][11][12][13][14][15] multi-shot molding, [10] and runner modifications to improve melt homogenization. [16,17] This work focuses on the mold modification of adding a reusable metal or single-use plastic static mixer to the runner system of a mold.…”

Section: F I G U R Ementioning

confidence: 99%

“…[ 1,6,7 ] In this way, both the injection molding process and mold are modified. Other novel approaches used for plastic optics include rapid heat cycle molding (RHCM), [ 5 ] conformal cooling systems, [ 8 ] micro‐injection molding, [ 1 ] process optimization and/or defect compensation via simulation, [ 9–15 ] multi‐shot molding, [ 10 ] and runner modifications to improve melt homogenization. [ 16,17 ]…”

Section: Introductionmentioning

confidence: 99%

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Effect of static mixer on optical properties of plastic injection molded parts

Shotwell

Gim

Yang

et al. 2022

Polymer Engineering & Sci

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The effect of an in‐mold static mixer on the optical properties of polystyrene (PS) parts was explored within the injection molding process. Several mixers were assessed via simulation and molding trials to identify the mixing ability and effect on optical properties including retardation and birefringence. It was found that the static mixers within the runner could successfully mix the polymer and disrupt property distributions including temperature but that there was only a slight improvement in retardation with some of the mixer cases. The experiments and simulations showed relatively good correlation in results although there were slight differences in the trends that could be due to the experimental measurement resolution or unaccounted‐for variables between the experiments and simulations. The retardation was experimentally measured using a custom‐made polariscope using photography and image processing. These experiments indicated that the use of a static mixer within the runner system of a mold could be used for homogenizing the polymer melt after the plasticizing unit. However, its effect on improving the optical performance of injection molded parts could be offset by the melt flow downstream of the static mixer and the potential increase of residual stresses due to flow restriction, suggesting the importance of mixer location and geometry.

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Section: F I G U R Ementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of static mixer on optical properties of plastic injection molded parts

Shotwell

Gim

Yang

et al. 2022

Polymer Engineering & Sci

View full text Add to dashboard Cite

show abstract

“…In this way both the injection molding process and mold are modified. Other novel approaches used for plastic optics include rapid heat cycle molding (RHCM) [5], conformal cooling systems [7], micro-injection molding [1], process optimisation and/or defect compensation via simulation [8-14], multi-shot molding [9], and runner modifications to improve melt homogenisation [15-20].…”

Section: Introductionmentioning

confidence: 99%

Development of runner reservoir and its effect on optical properties of small high-precision plastic injection molded parts

Shotwell

Lin

Liu

et al. 2023

Plastics, Rubber and Composites

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Adding reservoirs as extensions to a multi-cavity runner-system to regulate cavity fill-rate within small, high-precision optical parts during filling and fill-to-pack switch-over (F/P) was studied with the aid of simulations. This work aimed for a constant melt-front velocity inside the cavities with varying geometries. Three methods of reservoir designs were considered: first, using engineering intuition, second and third, using mass balance and mass and momentum balance equations, respectively. Eight reservoirs were designed and compared to two no-reservoir cases. For each case, 27 runs covering three levels of fill-rate, F/P, and packing pressure were simulated, resulting in 270 simulation runs. The quality variables of flow and thermally induced retardation and the average and standard deviation of volumetric shrinkage were considered and for each parameter, the minimum, best cases, occurred with a reservoir case. Thus, this study offers a proof-of-concept design for using reservoirs to improve molding of small, high-precision optical parts.

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“…The results obtained indicated that a predefined inhomogeneous refractive index and injectionmolding-induced warpage led to a distorted transmitted wavefront. 17 Moreover, Huang et al 18 conducted numerical simulations of the residual birefringence of injection-molded lenses. Combined with SHWFS experiments, these simulations showed that the transmitted wavefront was affected by refractive index changes and residual birefringence errors in injection-molded aspheric lenses.…”

Section: Introductionmentioning

confidence: 99%

Fabrication-error analysis of injection-molded aspheric elements using typical aberration terms in transmitted wavefront with Shack–Hartmann wavefront-sensing measurement

et al. 2020

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Aspheric lenses help meet the most demanding optical requirements while the precision injection molding technique hits the target for precision and cost. We developed a method of analyzing aberration terms in the transmitted "wavefront measurement," determined by Shack-Hartmann wavefront sensing to estimate the fabrication errors of injection-molded aspheric elements. Considering aspheric element fabrication using a small training data set and F-measure fuzzy cluster analysis, an unsupervised learning method was applied to extract typical aberration terms from the wavefront polynomial. The experimental results suggest that these aberration terms, which are related to spherical (third-, fifth-, and seventh-order) and coma (third-order) aberration terms in the transmitted wavefront polynomial expansion, can be employed to estimate the surface error and decenter, respectively, of a lens from a specific mold cavity. The sampling lenses evaluated in the proposed measuring process were collected from different mold cavities according to their total working performance in the modulated transfer function measurement for the whole camera module. The performances of the typical aberration terms were discussed by comparing to the ones obtained from an interferometer and a profilometer. The proposed method could provide high detection efficiency and can thus be applied for the quality control of aspheric elements for mobile phones, where the existing errors are mainly spherical, coma, and astigmatism aberrations. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Simulation and measurement of optical aberrations of injection molded progressive addition lenses

Cited by 20 publications

References 15 publications

Effect of static mixer on optical properties of plastic injection molded parts

Effect of static mixer on optical properties of plastic injection molded parts

Development of runner reservoir and its effect on optical properties of small high-precision plastic injection molded parts

Fabrication-error analysis of injection-molded aspheric elements using typical aberration terms in transmitted wavefront with Shack–Hartmann wavefront-sensing measurement

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