High-order aberration control during exposure for leading-edge lithography projection optics

2016 ◽  
Author(s):  
Yasuhiro Ohmura ◽  
Yosuke Tsuge ◽  
Toru Hirayama ◽  
Hironori Ikezawa ◽  
Daisuke Inoue ◽  
...  
Keyword(s):  
Leading Edge ◽  
High Order ◽  
High Order Aberration ◽  
Projection Optics

High-Order Aberration Measurement Method for Hyper-NA Lithographic Projection Lens

2017 ◽  
Vol 37 (4) ◽  
pp. 0412003
Author(s):  
诸波尔 Zhu Boer ◽  
王向朝 Wang Xiangzhao ◽  
李思坤 Li Sikun ◽  
孟泽江 Meng Zejiang ◽  
张恒 Zhang Heng ◽  
...  
Keyword(s):  
Measurement Method ◽  
High Order ◽  
Projection Lens ◽  
High Order Aberration

A wavefront aberrometer for dynamic high-order aberration measurement

Optik ◽  
2010 ◽  
Vol 121 (15) ◽  
pp. 1405-1411
Author(s):  
Xiang Yu ◽  
Yun Dai ◽  
Xuejun Rao ◽  
Cheng Wang ◽  
Lixia Xue ◽  
...  
Keyword(s):  
High Order ◽  
High Order Aberration

Influence of Misalignment on High-Order Aberration Correction for Normal Human Eyes

2008 ◽  
Vol 25 (4) ◽  
pp. 1309-1312 ◽  
Author(s):  
Zhao Hao-Xin ◽  
Xu Bing ◽  
Xue Li-Xia ◽  
Dai Yun ◽  
Liu Qian ◽  
...  
Keyword(s):  
High Order ◽  
Aberration Correction ◽  
High Order Aberration ◽  
Normal Human ◽  
Human Eyes

scholarly journals High Order Aberration Correction in a Post-Column Energy Filter

2010 ◽  
Vol 16 (S2) ◽  
pp. 56-57
Author(s):  
N Menon ◽  
M Barfels ◽  
RD Twesten
Keyword(s):  
High Order ◽  
Aberration Correction ◽  
High Order Aberration

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

scholarly journals Simultaneously measuring ocular aberration and anterior segment biometry during accommodation

2015 ◽  
Vol 08 (02) ◽  
pp. 1550005 ◽  
Author(s):  
Yuanyuan Wang ◽  
Yilei Shao ◽  
Yimin Yuan
Keyword(s):  
Anterior Segment ◽  
Crystalline Lens ◽  
Front Surface ◽  
High Order ◽  
Human Vision ◽  
Wavefront Aberrations ◽  
High Order Aberration ◽  
Key Factor ◽  
Set Up

In the human eye, accommodation is essential for functional vision. However, the mechanisms regulating accommodation and the ocular parameters affecting aberrations remain to be explored. In order to measure the alterations of ocular aberration and crystalline lens biometry during dynamic accommodative stimuli, we designed an optical coherence tomography with ultra-long penetration depth (UL-OCT) combined with a Shack–Hartmann wavefront sensor (SHWFS). This integrated set up measures human eye's anterior segment as well as monochromatic high-order aberrations (HOAs) with 6 μm resolution and (1/20) λ accuracy. A total of 10 healthy volunteers without ocular diseases were examined. Upon exposure to accommodative stimuli, the wavefront aberrations became larger. Among the anterior segment biometry, the anterior crystalline lens demonstrated significant curvature during accommodation and was the major cause of high-order aberration. These findings suggest that the front surface of the crystalline lens can significantly affect variation among aberrations, which is a key factor underlying the quality of human vision.

scholarly journals Contralateral Eye Study On The Characteristics of Corneal Aberration In Patients With Bilateral Keratoconus And Unilateral Corneal Vogt’s Striae

2021 ◽  
Author(s):  
Jing Li ◽  
Yaohua Zhang ◽  
Yong Li ◽  
Yan Cai ◽  
Jing Du ◽  
...  
Keyword(s):  
Spherical Aberration ◽  
Front Surface ◽  
High Order ◽  
Back Surface ◽  
Morphological Parameters ◽  
High Order Aberration ◽  
Contralateral Eye

Abstract Purpose: To assess the corneal high-order aberration(HOA) and its correlation with corneal morphological parameters in patients with bilateral keratoconus (KCN) and unilateral Vogt’s striae.Methods: A total of 168 eyes of 84 patients with KCN, whose corneas had definite signs of unilateral Vogt’s striae were enrolled. Corneal HOA and morphological parameters were measured using Pentacam HR.Results: The corneal morphological parameters between KCN eyes with and without Vogt’s striae were evidently different (P < 0.001). The 3rd coma 90°, 4th spherical aberration, 5th coma 90°, RMS (total), and RMS (HOA) in the front, back surfaces and total cornea in KCN eyes with Vogt’s striae were significantly higher than those in KCN eyes without Vogt’s striae (P < 0.001). In KCN eyes with Vogt’s striae, the 3rd coma 90° and 4th spherical aberration in the front surface and total cornea were negatively correlated with K1, K2, Km, Kmax, ACE, and PCE (P < 0.05). The 3rd coma 90° , 4th spherical aberration in back surface and RMS (total), RMS (HOA) in the front, back surfaces, total cornea were positively correlated with K1, K2, Km, Kmax, ACE, and PCE (P < 0.05).Conclusions: Corneal HOA especially vertical coma and spherical aberration may increase when Vogt’s striae appeared in KCN eyes. The scale of increase was significantly related with changes in corneal shapes.

scholarly journals High Order Aberration Outcomes of Corneal Collagen Crosslinking in Eyes with Keratoconus and Post-LASIK Ectasia

2014 ◽  
Vol 3 (3) ◽  
pp. 107-112
Author(s):  
Adam Muzychuk ◽  
Victor Penner ◽  
Guillermo Rocha
Keyword(s):  
Visual Acuity ◽  
Spherical Aberration ◽  
Retrospective Chart Review ◽  
High Order ◽  
Collagen Crosslinking ◽  
Distance Visual Acuity ◽  
High Order Aberration ◽  
Manifest Refraction ◽  
Corneal Collagen Crosslinking ◽  
Corneal Collagen

ABSTRACT Purpose To evaluate the effect of riboflavin and ultraviolet- A-induced corneal collagen crosslinking (CXL) on high order aberrations (HOA) up to third-order at 6 months using the iTrace wavefront aberrometer in patients with progressive keratoconus and post-LASIK ectasia. Materials and methods Ongoing retrospective chart review of patients having undergone CXL. The iTrace (Tracey Technologies, Houston, TX) was used to evaluate HOA. Patient data was collected from a single clinical site pre- and 6 months postoperatively. Data collected included logMAR uncorrected distance visual acuity (UDVA), logMAR corrected distance visual acuity (CDVA), manifest refraction, and HOA measurements. Data was analyzed with paired two-tailed student's t-test. Results 18 eyes (9M:4F, mean age 29.2 years, range 16-45) had 6 months of follow-up. Total HOAs, total coma and total trefoil were significantly reduced at 6 months by 16, 33 and 26% respectively (p < 0.05). Nonsignificant trends toward improvement were seen in spherical aberration, secondary astigmatism and UDVA. There were no statistically significant changes in manifest refraction or CDVA. Conclusion Improvement in high order aberration profile is one mechanism by which corneal collagen crosslinking enhances visual function in ectatic corneas. Total HOA and total coma measures are the most commonly reported improvements in HOA measures in previous studies, while total trefoil has only been observed in one other study. The improvements seen in HOAs remain fairly modest which likely accounts for the lack of measureable improvement in high-contrast visual acuity measures, such as Snellen UDVA and CDVA. This study is the first to report HOA outcomes with the iTrace wavefront aberrometer. How to cite this article Muzychuk A, Penner V, Rocha G. High Order Aberration Outcomes of Corneal Collagen Crosslinking in Eyes with Keratoconus and Post-LASIK Ectasia. Int J Kerat Ect Cor Dis 2014;3(3):107-112.

On the Effect of Inflow Disturbances on the Flow Past a Linear LPT Vane Using Spectral/hp Element Methods

2019 ◽  
Author(s):  
Andrea Cassinelli ◽  
Hui Xu ◽  
Francesco Montomoli ◽  
Paolo Adami ◽  
Raul Vazquez Diaz ◽  
...  
Keyword(s):  
High Performance ◽  
Leading Edge ◽  
High Order ◽  
Software Framework ◽  
Analysis Tool ◽  
Suction Surface ◽  
Present Contribution ◽  
Analysis And Design ◽  
Transition Mechanism ◽  
Moderate Reynolds Number

Abstract The recent development and increasing integration of high performance computing, scale resolving CFD and high order unstructured methods offers a potential opportunity to deliver a simulation-based capability (i.e. virtual) for aerodynamic research, analysis and design of industrial relevant problems in the near future. In particular, the tendency towards high order spectral/hp element methods is motivated by their desirable dispersion-diffusion properties, that are combined to accuracy and flexibility for complex geometries. Previous work from the Authors focused on developing guidelines for the use of these methods as a virtual cascade for turbomachinery applications. Building on such experiments, the present contribution analyzes the performance of a representative industrial cascade at moderate Reynolds number with various levels and types of inflow disturbances, adopting the incompressible Navier-Stokes solver implemented in the Nektar++ software framework. The introduction of a steady/unsteady spanwise-nonuniform momentum forcing in the leading edge region was tested, to break the flow symmetry upstream of the blade and investigate the change in transition mechanism in the aft portion of the suction surface. To provide a systematic synthetic turbulence generation tool, a parallelised version of Davidson’s method is incorporated and applied for the first time in the software framework to a low pressure turbine vane. The clean results of the cascade are compared to various levels of momentum forcing and inflow turbulence, looking at blade wall distributions, wake profiles and boundary layer parameters. Low levels of background disturbances are found to improve the agreement with experimental data. The results support the confidence for using high order spectral methods as a standalone performance analysis tool but, at the same time, underline the sensitivity at these flow regimes to disturbances or instabilities in the real environment when comparing to rig data.

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