Understanding Aspheric Lenses

Adams, Daniel E.; Ament, Shelby D. V.

doi:10.1002/opph.201800033

Cited by 9 publications

(2 citation statements)

References 4 publications

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“…Compared to large aperture optical systems, the imaging quality of small aperture optical systems is less affected by mid-spatial frequency surface errors with a given sub-aperture tool used in asphere manufacturing. In addition, mid-spatial frequency errors have less effect on larger 𝐹 ∕# optical systems than smaller 𝐹 ∕# optical systems [32]. As discussed in Section 3.1, the 𝐹 ∕# for the final ASPAL design is increased from 3.1 to 4.5 due to the difficulty of expelling air in small reflective surface G1 1 .…”

Section: Consideration Of Mid-spatial Frequency Surface Errors For Aspalmentioning

confidence: 99%

The Current Situation of Family Education and School and Kindergarten Admission of Migrant Children in Zhejiang Province, China: A Survey of Hangzhou, Ningbo and Jiaxing

Gao

Feng

et al. 2020

EJES

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Based on a survey of 322 parents of migrant children aged 3 to 10 in Hangzhou, Ningbo and Jiaxing, Zhejiang Province, China, the study found that nearly 70% of parents have been working in Zhejiang for 5-10 years, and 28% of them have worked for more than 10 years; 94% of them hold agricultural household registration and 6% of them hold non-agricultural household registration. Nearly 70% of these families have 2 to 3 children and 16% of them have 4 children. Those children who can get into the local public kindergartens and primary schools are all study in the local institutions and most school-aged children and the majority of pre-school children who do not meet the admission requirements for local public kindergartens and primary schools return to their hometown due to the pressure of tuition fees. At the same time, family education is not efficient, more than half of the children’s spare time is occupied by television and video games, the proportion of reading and sports activities is only a little more than 10%. Most parents have little time to read, do homework and physical exercise with their children, because of their heavy work or low level of education. This paper puts forward some relevant countermeasures and suggestions, hoping to change this situation. Article visualizations:<img src="/-counters-/edu_01/0629/a.php" alt="Hit counter" />

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Section: Consideration Of Mid-spatial Frequency Surface Errors For Aspalmentioning

confidence: 99%

The Current Situation of Family Education and School and Kindergarten Admission of Migrant Children in Zhejiang Province, China: A Survey of Hangzhou, Ningbo and Jiaxing

Gao

Feng

et al. 2020

EJES

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“…To improve optical properties, aspheric lenses, [18][19][20] which gradually change the curvature from the center of the lens out to the edge, can be used. Aspheric lenses may be designed to eliminate spherical aberration, create a wider field of view, and deliver improved spot size [21] and better peripheral vision with a more compact, lighter design. [19,20,22,23] Although every surface that deviates from spherical symmetry is an aspheric surface, optical designers typically consider aspheres to be nonspheric, rotationally symmetric surfaces.…”

mentioning

confidence: 99%

Polymer Stabilized Paraboloid Liquid Crystal Microlenses with Integrated Pancharatnam–Berry Phase

Perera

Padmini

Mann

et al. 2021

Advanced Optical Materials

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use spatially varying refractive index profiles to vary the effective refractive index n(r) and therefore, the optical path, n(r) × d. In PB phase lenses, in the plane of the lens the azimuthal angle (β) of the director varies with radius in the plane normal to the light path [11] causing the radial component of the refractive index to vary as well.Convex [12,13] or concave [14] lenses, such as eyeglasses, have simple spherical surfaces, while Fresnel [15][16][17] lenses have complex shapes that contain portions of a sphere. Even with a perfectly designed and manufactured spherical lens profile, some distortion, called spherical aberration, is created for light that passes through the lens away from its center. To improve optical properties, aspheric lenses, [18][19][20] which gradually change the curvature from the center of the lens out to the edge, can be used. Aspheric lenses may be designed to eliminate spherical aberration, create a wider field of view, and deliver improved spot size [21] and better peripheral vision with a more compact, lighter design. [19,20,22,23] Although every surface that deviates from spherical symmetry is an aspheric surface, optical designers typically consider aspheres to be nonspheric, rotationally symmetric surfaces. Mathematically, they are frequently described using conic sections for the radial dependence of the surface, [24] where the radial dependence of the surface profile z(r) along the lens' axis is given in Equation (1) as

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Applications of data fusion in optical coordinate metrology: a review

Zhang

Catalucci

Thompson

et al. 2022

Int J Adv Manuf Technol

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Data fusion enables the characterisation of an object using multiple datasets collected by various sensors. To improve optical coordinate measurement using data fusion, researchers have proposed numerous algorithmic solutions and methods. The most popular examples are the Gaussian process (GP) and weighted least-squares (WLS) algorithms, which depend on user-defined mathematical models describing the geometric characteristics of the measured object. Existing research on GP and WLS algorithms indicates that GP algorithms have been widely applied in both academia and industry, despite their use being limited to applications on relatively simple geometries. Research on WLS algorithms is less common than research on GP algorithms, as the mathematical tools used in the WLS cases are too simple to be applied with complex geometries. Machine learning is a new technology that is increasingly being applied to data fusion applications. Research on this technology is relatively scarce, but recent work has highlighted the potential of machine learning methods with significant results. Unlike GP and WLS algorithms, machine learning algorithms can autonomously learn the geometrical features of an object. To understand existing research in-depth and explore a path for future work, a new taxonomy of data fusion algorithms is proposed, covering the mathematical background and existing research surrounding each algorithm type. To conclude, the advantages and limitations of the existing methods are reviewed, highlighting the issues related to data quality and the types of test artefacts.

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Understanding Aspheric Lenses

Cited by 9 publications

References 4 publications

The Current Situation of Family Education and School and Kindergarten Admission of Migrant Children in Zhejiang Province, China: A Survey of Hangzhou, Ningbo and Jiaxing

The Current Situation of Family Education and School and Kindergarten Admission of Migrant Children in Zhejiang Province, China: A Survey of Hangzhou, Ningbo and Jiaxing

Polymer Stabilized Paraboloid Liquid Crystal Microlenses with Integrated Pancharatnam–Berry Phase

Applications of data fusion in optical coordinate metrology: a review

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