Tolerance analysis of misalignment in an optical system using Shack–Hartmann wavefront sensor: experimental study
01 Jul 2015-Optical Engineering (International Society for Optics and Photonics)-Vol. 54, Iss: 7, pp 075104-075104
TL;DR: In this article, the wavefront aberrations induced by misalignments due to decentration and tilt of an optical component in an optical measurement system are presented and the results are compared with experimental values.
Abstract: The wavefront aberrations induced by misalignments due to decentration and tilt of an optical component in an optical measurement system are presented. A Shack–Hartmann wavefront sensor is used to measure various aberrations caused due to the shifting of the axis and tilt of a lens in the path of an optical wavefront. One of the lenses in an optical system is decentered in the transverse direction and is tilted by using a rotational stage. For each step, wavefront data have been taken and data were analyzed up to the fourth order consisting of 14 Zernike terms along with peak-to-valley and root mean square values. Theoretical simulations using ray tracing have been carried out and compared with experimental values. The results are presented along with the discussion on tolerance limits for both decentration and tilt.
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01 Sep 2002
TL;DR: An OSA taskforce was formed at the 1999 topical meeting on vision science and its applications and charged with developing consensus recommendations on definitions, conventions, and standards for reporting of optical aberrations of human eyes.
Abstract: In response to a perceived need in the vision community, an OSA taskforce was formed at the 1999 topical meeting on vision science and its applications (VSIA-99) and charged with developing consensus recommendations on definitions, conventions, and standards for reporting of optical aberrations of human eyes. Progress reports were presented at the 1999 OSA annual meeting and at VSIA-2000 by the chairs of three taskforce subcommittees on (1) reference axes, (2) describing functions, and (3) model eyes.
85 citations
TL;DR: This paper uses a hybrid optical simulation model that comprises virtual and identified component positions that enables prediction of the future wavefront at the detector plane and therefore allows for taking corrective measures accordingly during the assembly process if a user-defined tolerance on the wavefront error is violated.
Abstract: Alignment of optical components is crucial for the assembly of optical systems to ensure their full functionality. In this paper we present a novel predictor-corrector framework for the sequential assembly of serial optical systems. Therein, we use a hybrid optical simulation model that comprises virtual and identified component positions. The hybrid model is constantly adapted throughout the assembly process with the help of nonlinear identification techniques and wavefront measurements. This enables prediction of the future wavefront at the detector plane and therefore allows for taking corrective measures accordingly during the assembly process if a user-defined tolerance on the wavefront error is violated. We present a novel notation for the so-called hybrid model and outline the work flow of the presented predictor-corrector framework. A beam expander is assembled as demonstrator for experimental verification of the framework. The optical setup consists of a laser, two bi-convex spherical lenses each mounted to a five degree-of-freedom stage to misalign and correct components, and a Shack-Hartmann sensor for wavefront measurements.
10 citations
TL;DR: The proposed sensitivity optimization method can homogenize image performance for the same field under different tolerance values and improves the product yield rate by 15 to 17% compared with a traditional optimization method.
Abstract: During the production of a lens system, the assembling and manufacturing tolerances must be accurately controlled to ensure production efficiency. Thus, it is important to analyze and optimize the tolerance sensitivity of the lens system during the optical design phase to reduce optical performance degradation. We proposed an approach for appropriately controlling the tolerance sensitivity of a lens system. The proposed sensitivity optimization method can homogenize image performance for the same field under different tolerance values. Based on the results, we show that the implementation of the proposed method sharply reduces sensitivity and, consequently, improves the product yield rate by 15 to 17% compared with a traditional optimization method. As a practical example, a 40-megapixel f1.8 mobile phone camera lens design and optimization process was performed in our study. Our preliminary experimental results confirm that the proposed method is effective to reduce the optical sensitivity of the camera lens.
References
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TL;DR: A mathematical model is proposed, which describes the modal wavefront reconstruction in terms of linear operators, and it is demonstrated that random masks with non-regular Fourier spectra provide absolute minimum error and allow to double the number of decomposition modes.
Abstract: The paper discusses the influence of the geometry of a Hartmann-(Shack) wavefront sensor on the total error of modal wavefront reconstruction. A mathematical model is proposed, which describes the modal wavefront reconstruction in terms of linear operators. The model covers the most general case and is not limited by the orthogonality of decomposition basis or by the method chosen for decomposition. The total reconstruction error is calculated for any given statistics of the wavefront to be measured. Based on this estimate, the total reconstruction error is calculated for regular and randomised Hartmann masks. The calculations demonstrate that random masks with non-regular Fourier spectra provide absolute minimum error and allow to double the number of decomposition modes.
37 citations
TL;DR: It is demonstrated that wave front analysis is a useful diagnostic tool, and that wavefront‐based corneal refractive surgery is an improvement over conventional techniques.
Abstract: In the 5 years since the first wavefront-based LASIK treatment on normal eyes, the ophthalmology profession has had to confront a new language based on astronomy, optics and mathematics. Over this time wavefront technology has been used for diagnosis and treatment, and its application has made the profession define what is meant by good vision, and determine whether, with psychophysical and psychometric tests, it is possible understand how an individual perceives the world. The clinical application of wavefront technology has forced ophthalmologists and vision scientists with an engineering bias to talk to those with a biological bias, and to appreciate that if you try and change the corneal shape, its biological, anatomical and optical properties exist within a complex external eye environment. This perspective article demonstrates that wave-front analysis is a useful diagnostic tool, and that wavefront-based corneal refractive surgery is an improvement over conventional techniques. Its use by an ophthalmologist is a clinical decision specific to an individual patient.
29 citations
TL;DR: A matrix method to do nonlinear calculations is described, applied to study refraction by a conic surface, and can be used to model corneal aberrations.
Abstract: A matrix method to do nonlinear calculations is described. This is possible only under the special condition when a transformation maps a zero vector onto a zero vector. Geometrical optics conform to this condition and hence matrix methods can be applied to calculate aberrations. Methods to reduce computational complexities using symmetry arguments are provided. The formalism is applied to study refraction by a conic surface. Aberration coefficients, up to fifth order, are obtained as functions of eccentricity and the latus rectum of the conic surface. The method can be used to model corneal aberrations.
14 citations
Book•
01 Jan 1989
TL;DR: Practical algorithms--tested, explained, and written in C--that scientists and engineers can use with little or no modification to solve the mathematical problems they encounter every day.
Abstract: Here are practical algorithms--tested, explained, and written in C--that scientists and engineers can use with little or no modification to solve the mathematical problems they encounter every day. The sure solution to faster, easier, and more accurate work.
13 citations
TL;DR: In this article, the authors describe objective and subjective spherical aberration measurements of the human eye and examine some of the most recent attempts to measure the aberrations of human eye.
Abstract: Publisher Summary This chapter describes objective and subjective spherical aberration measurements of the human eye. The concept of the human eye as an array of symmetric, centered, and homogeneous optical elements has promoted the study of its basic optical characteristics. Using this type of modeling, the human eye is considered as a two element optical system composed of a corneal lens, a crystalline lens, and an image plane coinciding with the retina. These elements are illustrated in the chapter. This array can be analyzed by the use of paraxial ray trace techniques to locate the principal planes, nodal points, and the anterior and posterior focal planes of the eye. To understand the aberration measurements of the human eye, the chapter describes the components of the visual system and examines some of the most recent attempts to measure the aberrations of the human.
9 citations
Additional excerpts
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