Results 201 to 210 of about 102,275 (261)
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Aberration design of zoom lens systems using thick lens modules
Applied Optics, 2014A systematic approach for the aberration design of a zoom lens system using a thick lens module is presented. Each component is treated as a thick lens module at the beginning of the design. A thick lens module refers to a thick lens component with a real lens structure, like lens materials, lens curvatures, lens thicknesses, and lens interval ...
Jinkai, Zhang +3 more
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Corneal Thickness Measurements Following Intraocular Lens Implantation
Ophthalmic Surgery, Lasers and Imaging Retina, 1977SUMMARY Corneal thickness measurements were carried out on patients who had undergone combined phacoemulsification cataract extraction with simultaneous intraocular lens implantation in one eye at least six months prior to the date of measurement. The unoperated eye served as control.
D L, Praeger, H A, Schneider
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Optician, 2016
Andy Sanders takes a look at lens thickness and what should be borne in mind to offer our patients the best appearance and wearing comfort when dispensing any particular refractive correction.
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Andy Sanders takes a look at lens thickness and what should be borne in mind to offer our patients the best appearance and wearing comfort when dispensing any particular refractive correction.
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Accuracy of New Intraocular Lens Power Calculation Formulas: A Lens Thickness Study
Journal of Refractive Surgery, 2021PURPOSE: To investigate whether using lens thickness measurement as an optional input improves the refractive accuracy of four new generation formulas. METHODS: Consecutive patients scheduled for cataract surgery were enrolled.
Leonardo, Taroni +4 more
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Characteristics of the thick, compound refractive lens
Applied Optics, 2003A compound refractive lens (CRL), consisting of a series of N closely spaced lens elements each of which contributes a small fraction of the total focusing, can be used to focus x rays or neutrons. The thickness of a CRL can be comparable to its focal length, whereupon a thick-lens analysis must be performed.
Richard H, Pantell +5 more
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Application of Hydrogel Lens Average Thickness
Optometry and Vision Science, 1984The equation for the average thickness of a hydrogel lens is a complex function. This report gives a simple method of estimating this parameter. By structuring the information into nomograms, an accurate system is derived which facilitates the design of a contact lens to provide a required average oxygen transmissibility.
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Laser differential confocal lens thickness measurement
Measurement Science and Technology, 2012Based on the property that the absolute zero of an axial intensity curve exactly corresponds to the focus of the objective in a differential confocal system (DCS), a new laser differential confocal lens thickness measurement is proposed to achieve the high-precision non-contact measurement of lens thickness. The proposed approach uses the absolute zero
Yun Wang +3 more
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2020
Any real lens is a thick lens, meaning that it has a non-zero lens thickness t , which is the axial separation between the vertexes of the two refracting surfaces. Lens thickness is a nondirectional distance (therefore, is always positive), measured at the center of the lens along the optical axis (i.e., the lens is not tilted), regardless of the shape
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Any real lens is a thick lens, meaning that it has a non-zero lens thickness t , which is the axial separation between the vertexes of the two refracting surfaces. Lens thickness is a nondirectional distance (therefore, is always positive), measured at the center of the lens along the optical axis (i.e., the lens is not tilted), regardless of the shape
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The Definition of Thickness for a Lens
Optometry and Vision Science, 1979The thickness of a lens depends upon the direction of the measuring vector. The thickness as commonly used from the sagittal height formula does not give the path length for movement of gas, water, and heat through a lens. Furthermore, the amount of gas, water, or heat moving through a lens depends upon an areal average thickness, not central thickness.
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A Satisfying “Thick Lens” Experiment
American Journal of Physics, 1957An elementary experiment is described in which an object-image relationship for a thick lens is determined both by experiment and by calculations involving easily determined lens parameters. The two methods have over-all errors of less than 6% and agree quite well.
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