Wide-field Lens Research Articles

The clinical evaluation of a widefield lens to expand the field of view in optical coherence tomography (OCT-A)

This study aimed to evaluate the clinical benefits of incorporating a widefield lens (WFL) in optical coherence tomography angiography (OCT-A) in patients with retinal vascular diseases in comparison to standard single-shot OCT-A scans. Sixty patients with retinal vascular diseases including diabetic retinopathy (DR) and retinal vein occlusion (RVO) were recruited. OCT-A imaging (PlexElite 9000) with and without WFL was performed in randomized order. The assessment included patient comfort, time, field of view (FoV), image quality and pathology detection. Statistical analysis included paired t-tests, Mann–Whitney U-tests and Bonferroni correction for multiple tests, with inter-grader agreement using the kappa coefficient. Using a WFL did not lead to statistically significant differences in DR and RVO group test times. Patient comfort remained high, with similar responses for WFL and non-WFL measurements. The WFL notably expanded the scan field (1.6× FoV increase), enhancing peripheral retinal visibility. However, image quality varied due to pathology and eye dominance, affecting the detection of peripheral issues in RVO and DR cases. The use of a WFL widens the scan field, aiding vascular retinal disease imaging with minor effects on comfort, time, and image quality. Further enhancements are needed for broader view angles, enabling improved quantification of non-perfused areas and more reliable peripheral proliferation detection.

Single-shot wide-field full-stokes polarization imaging

Polarization is an intrinsic property of light. With the advancements in nanophotonics, it is now possible to achieve arbitrary polarization transformations in space. Incorporating special functions in different spatial dimensions expands the design freedom of metasurfaces and other optical devices. To understand and utilize the metasurface, we design a metasurface optical element to achieve single-shot, wide-field polarization imaging. Our demonstration exhibits a compact, full Stokes wide-field polarization imaging device without requiring conventional optical elements, such as moving parts or wide-field lens sets. Wide-field polarization imaging devices are potential candidates for machine vision and biological tissue imaging applications.

Comparison of Methods Used to Prevent Fogging of a Non-contact Wide-field Viewing System during Vitrectomy

Purpose: To compare the effectiveness of warm saline and anti-fog solution for preventing fogging of a non-contact wide-field viewing system during vitrectomy.Methods: Five liters of water at 36°C were placed in a transparent container. The fogging areas of wide-field lenses were microscopically measured. We created three groups: lenses soaked in normal saline at 25°C for 1 minute (control), lenses soaked in normal saline at 50°C for 1 minute (warm saline), and lenses that were wiped with a sponge soaked in anti-fog solution (ULTRASTOP pro med. Solution, Sigmapharm, Vienna, Austria) after prior soaking in normal saline at 25°C for 1 minute (anti-fog). Images of fogged areas were acquired at 10 seconds and 1, 3, and 5 minutes. Extent of fogged areas and central lens invasion were determined. All experiments were repeated 10 times.Results: In the control group, the entire areas were always completely fogged. The average fog coverage values were 4.34 ± 1.28, 6.30 ± 1.38, 56.00 ± 25.01, and 93.81 ± 5.88% at 10 seconds and 1, 3, and 5 minutes in the warm saline group and 4.74 ± 0.57, 7.35 ± 0.96, 10.13 ± 1.09, and 11.74 ± 1.74% in the anti-fog group, respectively. There were significant differences at 3 and 5 minutes (p = 0.029, p = 0.012). Fogging of the central lens was detected in 8 tests after 3 minutes and all 10 tests after 5 minutes in the warm saline group, but no fogging was detected in the anti-fog group.Conclusions: Application of an anti-fog solution to a wide-field viewing lens prevents lens fogging during vitrectomy.

Design and analysis of performance for wider field of view of concentrator

A novel wider field of view of concentrators, which is composed of an optical fisheye lens with wider field of view and a traditional compound parabolic concentrator (CPC), is proposed in this paper. In this novel concentrator, exits of rays of meniscus fisheye lens and entrances of rays of CPC is fitted tightly on the basis of principles of ray trace, so that the proposed concentrator can be used to concentrate higher optical power than traditional CPC. In this paper, based on the geometry construction model of the new wide-field concentrator is established, the optics simulation software of TracePro is employed to model and design the structure of the concentrator, and analyses of performances for the concentrator is also carried out. The results show that this new wide-field concentrator can significantly increase the light energy received by the concentrator compared with a conventional concentrator without a wide-field fisheye lens, and can significantly improve the performance of LED wireless optical communication systems if used in the receiving optical antenna of LED wireless optical communication systems.

Spectral-domain optical coherence tomography characteristics of cystic retinal tuft

ObjectiveTo investigate the characteristics of cystic retinal tufts (CRTs) with 55° widefield spectral-domain optical coherence tomography.MethodsThis was a retrospective study. All subjects underwent a complete ocular examination, ultra-widefield (UWF) pseudocolor fundus photography and Spectral domain optical coherence tomography (SD-OCT) with a 55° widefield lens. The SD-OCT characteristics were analyzed in subjects with CRT.ResultsTwenty-six eyes of 25 subjects were scanned and 29 CRTs were analyzed for SD-OCT characteristics. On SD-OCT images, the CRTs exhibited hyperreflective irregular elevated lesions with internal hyporeflective cystoid cavities. Normal layers of the neuroepithelium could not be distinguished. The mean diameter of CRTs was 1022 microns (range, 117–3711 microns; standard deviation, 815 microns). There was vitreoretinal traction at the apex of CRTs. Among them, retinal tears in 24.14% (7/29), suspected retinal tears in 27.59% (8/29), and shallow neuroepithelium detachment in 31.03% (9/29).ConclusionsThe widefield SD-OCT imaging can provide detailed cross-sectional anatomic information of CRT and may guide clinical treatment.

Influence of the scleral indentation technique on the re-detachment rate following retinal detachment surgery

PurposeThe aim of this study was to determine whether the choice of scleral indentation technique during primary rhegmatogenous retinal detachment surgery has an influence on the risk of re-detachment.MethodsWe included retrospectively 154 eyes with a primary rhegmatogenous retinal detachment treated in the Eye Clinic Sulzbach/Saar Germany, who were operated on by two experienced surgeons using the same basic surgical setup. Surgeon A performed an external 360° indentation, shaved the vitreous base using the light pipe cap, and used the operating microscope (opm) for direct visualization. Surgeon B performed an external 360° indentation, shaved the vitreous base using a simple indentor, and used an endoillumination (light pipe) with the opm and a handheld widefield lens for direct visualization.ResultsComparing both indentation procedures, 15.66% (13/83) of patients operated on by surgeon A and 9.86% (7/71) of patients operated on by surgeon B had a retinal re-detachment within a follow-up period of 6 months (adj. p = 0.64, two-proportion Z-test).ConclusionThe rate of retinal re-detachment could be influenced by the indentation technique at the end of surgery favoring external indentation and internal visualization with an endoilluminator (chandelier light). We attribute this to the better visualization of the vitreous base facilitated by endoillumination. However, many variables play a role in the development of retinal re-detachment, requiring further studies with a larger number of patients.

Development of Machine Vision System for Off-Line Inspection of Fine Defects on Glass Screen Surface

The complicated manufacturing process and poor industrial environment inevitably produces unacceptable scratches on glass screen surface. In this study, a machine vision system is developed to automatically detect fine scratch, which has a width smaller than 30 μm, on glass screen surface for the purpose of appearance quality assessment. The imaging hardware of the proposed machine vision system is made up of a high-resolution camera and a wide field lens so that a high-quality image is achieved in a relatively large image area. The captured glass screen images were firstly classified with YOLOv3 to exactly distinguish fine scratches in two other kinds of defects including dusts and stains. Then the U-Net network was applied on the selected scratches to estimate their dimensions approximately. The proposed algorithms combination has a fast image processing speed and it is able to effectively reduce the false segmentation of other defects. The results of the developed machine vision system show a relatively good agreement with the well-established microscopic method. It demonstrates our machine vision method is able to image and quantitative analyze scratches with dimensions between 25 μm to 100 μm.

Lithography Solutions for Submicron Panel-Level Packaging

Abstract Heterogeneous Integration of logic, memory, photonic, analog and other value-adding functions is one approach for increasing electronic system efficiency, performance and bandwidth while helping reduce overall manufacturing costs. To capitalize on Heterogeneous Integration benefits, designers are requiring finer resolution Redistribution Layer patterning and larger package sizes to maximize System-in-Package integration possibilities. Production of large-package electronics systems is well-suited for Panel Level Packaging (PLP) and achieving uniform submicron patterning across the entire rectangular panel is a key lithography challenge. To meet this challenge, Canon developed the first lithography exposure system or stepper that is capable of achieving submicron resolution on 500 mm panels. The stepper features a panel handling system for processing panels up to 515 mm x 515 mm in size and is also equipped with wide-field projection lens featuring a maximum 0.24 Numerical Aperture and a large 52 mm x 68 mm image field. This paper will report on evaluation results for a submicron PLP process using the panel stepper and will introduce high-resolution PLP process challenges including warped panel handling. Process results on Copper Clad Laminate (CCL) substrates will be reported including pattern uniformity, adjacent shot stitching accuracy and overlay accuracy on substrates containing die-placement error that is common in Fan-Out processes.

Spectral-Domain Optical Coherence Tomography Imaging of the Typical cystoid degeneration

ABSTRACT Purpose: To describe the spectral-domain optical coherence tomography (SD-OCT) features of typical cystoid degeneration. Methods: This was a retrospective study of 11 eyes with typical cystoid degeneration (TCD). All patients had a complete ocular examination, ultra-widefield (UWF) pseudocolor fundus photography and SD-OCT with a 55° wide-field lens. We analyzed the cross-sectional structural information of SD-OCT imaging with TCD. Results: On SD-OCT, the TCD regions exhibited rolling hills patterns with irregularly elevated retinal surface, and multiple intraretinal hyporeflective cavities separated by irregular septums were seen in the neurosensory retina. Destructive changes were seen in the ellipsoid zone and the pigment epithelium. Consolidated vitreous with moderate to high reflectivity was seen over the lesion and there might be vitreoretinal adhesions and tractions. Results: SD-OCT shows exquisite structural features of the anatomy in vivo detail of the TCD. This imaging technique may deepen our structural understanding of TCD and may influence decision-making in clinical practice.

Droplet coalescence and phase separation in a topical ointment: Effects of fluid shear and temperature

The physical stability of a prototypical pharmaceutical topical ointment, consisting primarily of an emulsion of propylene glycol droplets dispersed in a continuous white petrolatum medium, was studied with regard to droplet size growth and phase separation when the ointment undergoes heating or fluid shear. To investigate the effects of shear, the ointment at 32°C was sheared using a transparent, narrow-gap, temperature-controlled Taylor-Couette flow apparatus operated under laminar flow conditions which provided approximately uniform shear rates. Optical methods based on microscopy were used to obtain in-situ, time-dependent propylene glycol droplet size distributions, while a wide-field lens and camera were simultaneously used to detect gross phase separation as the ointment was sheared. Microscopy was also used to observe and quantify ointment stability via analysis of droplet size evolution in the absence of fluid shear for a range of elevated temperatures. For a quiescent ointment, it was observed that the dispersed propylene glycol droplets do not exhibit any appreciable growth over a period of one month and temperatures as high as 45°C. In contrast, fluid shear imposed at 32°C was observed to cause rapid growth of dispersed phase droplets and the onset of large phase separated regions on time scales ranging between a few minutes to approximately half an hour for fluid strain rates ranging between 5.5 and 50s-1, respectively. The experimental results from the lab-scale Couette flow apparatus were used to evaluate the risk of phase separation during commercial-scale manufacturing.

MASCARA-4 b/bRing-1 b: A retrograde hot Jupiter around a bright A-type star

Context. The Multi-site All-Sky CAmeRA (MASCARA) and bRing are both photometric ground-based instruments with multiple stations that rely on interline charge-coupled devices with wide-field lenses to monitor bright stars in the local sky for variability. MASCARA has already discovered several planets in the northern sky, which are among the brightest known transiting hot Jupiter systems. Aims. In this paper, we aim to characterize a transiting planetary candidate in the southern skies found in the combined MASCARA and bRing data sets of HD 85628, an A7V star of V = 8.2 mag at a distance 172 pc, to establish its planetary nature. Methods. The candidate was originally detected in data obtained jointly with the MASCARA and bRing instruments using a Box Least-Square search for transit events. Further photometry was taken by the 0.7 m Chilean-Hungarian Automated Telescope (CHAT), and radial velocity measurements with the Fiber Dual Echelle Optical Spectrograph on the European Southern Observatory 1.0 m Telescope. High-resolution spectra during a transit were taken with the CTIO high-resolution spectrometer (CHIRON) on the Small and Moderate Aperture Research Telescope System 1.5 m telescope to target the Doppler shadow of the candidate. Results. We confirm the existence of a hot Jupiter transiting the bright A7V star HD 85628, which we co-designate as MASCARA-4b and bRing-1b. It is in an orbit of 2.824 days, with an estimated planet radius of 1.53−0.04+0.07 RJup and an estimated planet mass of 3.1 ± 0.9 MJup, putting it well within the planetary regime. The CHAT observations show a partial transit, reducing the probability that the transit was around a faint background star. The CHIRON observations show a clear Doppler shadow, implying that the transiting object is in a retrograde orbit with |λ| =244.9−3.6+2.7°. The planet orbits at a distance of 0.047 ± 0.004 AU from the star and has a zero-albedo equilibrium temperature of 2100 ± 100 K. In addition, we find that HD 85628 has a previously unreported stellar companion star in the Gaia DR2 data demonstrating common proper motion and parallax at 4.3′′ separation (projected separation ~740 AU), and with absolute magnitude consistent with being a K/M dwarf. Conclusions. MASCARA-4 b/bRing-1 b is the brightest transiting hot Jupiter known to date in a retrograde orbit. It further confirms that planets in near-polar and retrograde orbits are more common around early-type stars. Due to its high apparent brightness and short orbital period, the system is particularly well suited for further atmospheric characterization.

QD laser eyewear as a visual field aid in a visual field defect model

Visual field defects interfere with free actions and influence the quality of life of patients with retinitis pigmentosa; the prevalence of this disease is increasing in aging societies. Patients with progressive disease may require visual aids; however, no such devices are currently available. We utilized a retinal projection eyewear system, QD laser eyewear, which includes a projector inside the spectacle frame, to draw the image taken by a connected portable camera with a wide field lens. The images are projected onto the retina using a Maxwellian view optical system, which is not influenced by refractive error or the amount of incident light. Goldmann perimetry and figure recognition tests with the QD laser eyewear showed increased visual field areas and angles, and shortened the time for recognition of the number of figures in a sheet, in a limited visual field model that we developed by using a pin-hole system to simulate the tunnel vision of retinitis pigmentosa in 19 healthy adults. The device supported the quality of vision. Additionally, the visual field defect model used in healthy adults was useful for validating the device in the development stage of the study, to clarify both advantages and future goals for improving the device.

Measurement of diameter of cylindrical openings using a disk beam probe

The diameter of cylindrical openings is conventionally measured with the mechanical and contact method. In this paper, we propose a contactless optical approach to measure dimensions of inner profile by a disk beam probe. The measurement is carried out illuminating the inner cylindrical opening with a light sheet generated by the disk beam probe, acquiring the light-section image of the object with an image sensor through a widefield lens, then numerically extracting the diameter. During measurement, the probe is aligned inside the openings with high freedom, which causes the optical section to manifest a variety of ellipses besides a circle accordingly. The measurement method copes with extracting the diameter of openings from various ellipse optical sections. The high freedom of probe alignment allows optical diameter measurement to be flexible and simple. The dimensions of cylindrical openings of manufactured parts were practically measured with the disk beam probe, and the results were confirmed with those measured with the vernier caliper.

360-degree large-scale multiprojection light-field 3D display system.

This paper proposes a 360-deg large-scale multiprojection light-field 3D display system, which can reconstruct the light field of models in real space. The reconstructed contents can be observed by multiple viewers from different angles and positions simultaneously. In this system, 360 projectors project images onto a cylindrical light-field diffusion screen whose height is 1.8m and diameter is 3m. When moving around the system, viewers can see 3D scenes with smooth-motion parallax, and the frame rate can reach 30fps and above. To achieve a large-scale display, we design a wide-field lens with cylindrical lenses to enlarge the projection image. To promote efficiency of data transmission and render 3D contents in real time, we apply computers equipped with multiple graphic cards, and display data are divided by field programmable gate array. Finally, a 360-deg light-field autocalibration method based on CCD and multiview sampling is proposed, whose calibration effect is strongly confirmed by experiment results.

Hyper-track selector nuclear emulsion readout system aimed at scanning an area of one thousand square meters

Automatic nuclear emulsion readout systems have seen remarkable progress since the original idea was developed almost 40 years ago. After the success of its full application to a large-scale neutrino experiment, OPERA, a much faster readout system, the hyper-track selector (HTS), has been developed. HTS, which has an extremely wide-field objective lens, reached a scanning speed of 4700 cm$^2$/h, which is nearly 100 times faster than the previous system and therefore strongly promotes many new experimental projects. We will describe the concept, specifications, system structure, and achieved performance in this paper.

The Multi-site All-Sky CAmeRA (MASCARA)

This paper describes the design, operations, and performance of the Multi-site All-Sky CAmeRA (MASCARA). Its primary goal is to find new exoplanets transiting bright stars, $4 < m_V < 8$, by monitoring the full sky. MASCARA consists of one northern station on La Palma, Canary Islands (fully operational since February 2015), one southern station at La Silla Observatory, Chile (operational from early 2017), and a data centre at Leiden Observatory in the Netherlands. Both MASCARA stations are equipped with five interline CCD cameras using wide field lenses (24 mm focal length) with fixed pointings, which together provide coverage down to airmass 3 of the local sky. The interline CCD cameras allow for back-to-back exposures, taken at fixed sidereal times with exposure times of 6.4 sidereal seconds. The exposures are short enough that the motion of stars across the CCD does not exceed one pixel during an integration. Astrometry and photometry are performed on-site, after which the resulting light curves are transferred to Leiden for further analysis. The final MASCARA archive will contain light curves for ${\sim}70,000$ stars down to $m_V=8.4$, with a precision of $1.5\%$ per 5 minutes at $m_V=8$.

Design and analysis of miniature high-resolution omnidirectional gaze optical imaging system

A miniature high-resolution omnidirectional gaze optical imaging system comprising one optical low-pass filter and 5 lens elements with just one aspheric surface was successfully designed. The total tracking length of the system is 14.7 mm and fit on a 5MPx 2/3in CCD with 2448 × 2050 pixel of 3.45 μm for the full 360° × 200° imaging. We introduced the difficulties in the design of ultrawide field of view system and proposed specific computations to overcome them by aberration theories, furthermore making a simulated analysis and performance evaluation using ZEMAX optical design software. The result shows that an admirable corrected field curvature along with a low F-theta distortion, and a perfect lateral and longitudinal color aberration correction were achieved; relative illumination of all field is over 68%; when the ambient temperature changes from −40 to 70 ℃, the modulation transfer function performs in a steady range at 75 lp/mm; all of these will promote the wide-field lens application in medical, automotive, and stereo vision.

Design of a Tele-centric Wide Field Lens with High Relative Illumination and Low Distortion Using Third-order Aberration Analysis

This paper presents a design method for improving the low relative illumination and large distortion due to widening the field of a system. A tele-centric optical system in image space was suggested to increase the relative illumination. Through the analyses of the third-order aberrations affected by introducing aspherical surfaces, we have proposed a method to determine analytically what surface should be aspheric to correct each aberration effectively. By utilizing this method to design a wide field lens, a tele-centric wide field lens with f-number of F/2.0 was obtained. Even though the field angle is 120 degrees, it has a very low distortion less than -2% and high relative illumination more than 73.7%. In conclusion, this analytic method for selecting aspherical surfaces is expected to serve as a useful way to find design solutions.

ANALYSIS OF A CONFOCAL SCANNING LASER OPHTHALMOSCOPE NONCONTACT ULTRA-WIDE FIELD LENS SYSTEM IN RETINAL AND CHOROIDAL DISEASE.

Espina, Mark P. MD; Arcinue, Cheryl A. MD; Ma, Feiyan MD; Camacho, Natalia MD; Bartsch, Dirk-Uwe G. PhD; Freeman, William R. MD Author Information

Distortion correction for the orthogonally-splitting-imaging pose sensor

Abstract The orthogonally-splitting-imaging pose sensor utilizes not only large field of view spherical lenses but also two sets of cylindrical ones to realize the high-speed, high-precision and wide-field pose measurement. Notable distortion, however, results from the wide-field lenses at the same time. Therefore, to obtain the best performance of the camera model, a distortion correction method is proposed in this paper, which combines the advantages of the high-stability of the Least Square fittings based on the orthogonal polynomials and the independence of the distortion correction based on the cross-ratio invariability. In this way, the ill-conditioned fitting matrix as well as the iteration and optimization procedures in solving extrinsic and intrinsic parameters can be avoided. Due to the wide fitness of the cross-ratio invariability and the orthogonal polynomials, this distortion correction technique is also suitable to other optical set up with different imaging structure. The experiment results that the corrected grids have superior precision and reliability with their original slopes demonstrate that the distortion model on the basis of orthogonal polynomial is validated and that the distortion correction is effective.