Lens Assembly Research Articles

Achromatic triplet and athermalized lens assembly for both midwave and longwave infrared spectra

Analytic solutions for finding the achromatic triplet in the midwave and longwave infrared spectra simultaneously are explored. The relationship between the combination of promising refractive materials and the system’s optical power is also formulated. The principles for stabilizing the effective focal length of an air-spaced lens group with respect to temperature are explored, and the thermal properties of the optical component and mechanical elements mutually counterbalanced. An optical design based on these achromatic and athermal theories is demonstrated, and the image quality of the lens assembly seems to approach the diffractive limitation.

Automated Digital Microfluidic Platform for Magnetic-Particle-Based Immunoassays with Optimization by Design of Experiments

We introduce an automated digital microfluidic (DMF) platform capable of performing immunoassays from sample to analysis with minimal manual intervention. This platform features (a) a 90 Pogo pin interface for digital microfluidic control, (b) an integrated (and motorized) photomultiplier tube for chemiluminescent detection, and (c) a magnetic lens assembly which focuses magnetic fields into a narrow region on the surface of the DMF device, facilitating up to eight simultaneous digital microfluidic magnetic separations. The new platform was used to implement a three-level full factorial design of experiments (DOE) optimization for thyroid-stimulating hormone immunoassays, varying (1) the analyte concentration, (2) the sample incubation time, and (3) the sample volume, resulting in an optimized protocol that reduced the detection limit and sample incubation time by up to 5-fold and 2-fold, respectively, relative to those from previous work. To our knowledge, this is the first report of a DOE optimization for immunoassays in a microfluidic system of any format. We propose that this new platform paves the way for a benchtop tool that is useful for implementing immunoassays in near-patient settings, including community hospitals, physicians' offices, and small clinical laboratories.

Differentiation of basidiospores by MALDI-TOF lipid profiling

Lipid profiles of microorganisms, such as bacteria and fungi, have been studied intensively and have shown great potential for species differentiation. However, lipid profiles of basidiospores are seldom reported in the literature. In this study, the MALDI-TOF mass spectra of lipids extracted from basidiospores of Auricularia auricula, Agaricus bisporus, Hypsizygus marmoreus, Lentinus edodes, Pleurotus ostreatus, and Volvariella volvacea were obtained using a laboratory-built MALDI-TOF mass spectrometer, equipped with an aerodynamic lens assembly as a direct deposition interface. The sample preparation strategies included matrices, solvents, and analyte/matrix ratios, which were optimized to acquire reproducible and informative mass spectra of lipid mixtures. Phospholipids, diacylglycerols, and triacylglycerols were observed by mixing the lipid extracts with equal volumes of 2,4-DHB/methanol solution (10mg/mL). Species-specific lipid profiles of basidiospores were obtained. The experimental results demonstrate that the lipid profiles can be used to differentiate basidiospores.

Design of High Pixel Mobile Phone Camera Lens

The compact, slim and high pixel mobile phone camera is highly demanded with the development of mobile phone, especially the thinner and thinner request of people. To satisfy this need, a mobile phone lens system composed of 1 glass spherical lens and 3 plastic aspheric lenses was designed with Code V. The F-number was 2.85 and FOV was 61°, the effective focal length and back focal length are 5 and 0.468 mm, respectively. A 1/3.2 inch 8 mega-pixel CMOS made by APTINA was taken as the image sensor of the lens assembly, whose pixel size is 1.4 μm and the limiting resolution was 357 lp/mm. The design results shown that the M TF value was more than 0.2 within most fields of view at the Nyquist frequency and more than 0.5 at the 1/2 Nyquist frequency, the maximum distortion was 0.66%. It shows that the lens has good performance and meets practical requirements.

A Monte Carlo analysis of uncertainty in supporting assembly of large-aperture optical lenses

Large-aperture lenses are widely used to improve optical resolution and enlarge field of view of a precision optical system, and reasonable mounting can result in higher optical performance. Flexure mounts are usually utilized to minimize distortion of the lens under its own weight and must be accurately assembled so as to provide uniform support loads for the lens. The supporting loads produced by flexure mounts are difficult to be identical because of various uncertainties during assembly process, such as human operation and tool resolution. These nonuniform supporting loads may generate asymmetric deformation of the lens and deteriorate its performance. It is essential to explore the influence of uncertainty supporting loads on the optical performance. A Monte Carlo analysis method is proposed to investigate the optical performance of a lens under uncertainty supporting loads at different load levels. Patran Command Language is used for repetitive calculation of finite element model with random sample of supporting loads. The optical performance responses, such as the surface peak-to-valley and root-mean-square errors and Zernike coefficients, are calculated by fitting the surface deformation data, and their stochastic properties are researched by statistical testing. Consequently, the critical variation range of uncertainty supporting loads considering assembly process can be determined based on Three Sigma theorem with specific optical performance requirement. The results can be used to assign appropriate tolerance of flexure mounts during assembly and to optimize the supporting system of a high-precision optical system.

Tunable lenses using transparent dielectric elastomer actuators

Focus tunable, adaptive lenses provide several advantages over traditional lens assemblies in terms of compactness, cost, efficiency, and flexibility. To further improve the simplicity and compact nature of adaptive lenses, we present an elastomer-liquid lens system which makes use of an inline, transparent electroactive polymer actuator. The lens requires only a minimal number of components: a frame, a passive membrane, a dielectric elastomer actuator membrane, and a clear liquid. The focal length variation was recorded to be greater than 100% with this system, responding in less than one second. Through the analysis of membrane deformation within geometrical constraints, it is shown that by selecting appropriate lens dimensions, even larger focusing dynamic ranges can be achieved.

光谱共焦显微镜的线性色散物镜设计

As the nonlinearity between the Axial Chromatic Aberration(ACA)and the wavelength of a dispersive objective would lower the overall performance of a chromatic confocal microscope,the dependence of the ACA of an optical system on the lens assembly was studied and the transfer principle of ACA was derived.Based on ACA transfer principle,a dispersive objective configured with a negative and a positive lens groups was proposed,in which both the negative and positive lens groups could generate the linear ACA with specified focal power distribution.Optimized result indicates that the dispersive objective based on the proposed configuration has small longitudinal aberration,a large ACA,and a long working distance.The ACA of dispersive objective is 1mm in 430-710nm.The relative nonlinearity of ACA is about 4.6% and the deviation of sensitivity is less than 1/3 that of a whole,superior to traditional ones.With designed dispersive objective,the chromatic confocal microscope can achieve an axial resolution of 0.3μm and a lateral resolution of 5μm,which satisfies the requirements of precise measurement.

Thermal optical path difference analysis of the telescope correct lens assembly

Abstract The effect of correct lens thermal optical path difference (OPD) on the optical performance of the Cassegrain telescope system is presented. The correct lens assembly includes several components such as a set of correct lenses, lens mount, spacer, mount barrel, and retainer. The heat transfer from the surrounding environment to the correct lens barrel will cause optical system aberration. The temperature distribution of the baffle is from 20.546°C to 21.485°C. Meanwhile, the off-axis ray’s path of the OPD has taken the lens incidence point and emergence point into consideration. The correct lens temperature distribution is calculated by the lens barrel heat transfer analysis; the thermal distortion and stress are solved by the Finite Element Method (FEM) software. The temperature distribution is weighted to each incidence ray path, and the thermal OPD is calculated. The thermal OPD on the Z direction is transferred to optical aberration by fitting OPD into a rigid body motion and the Zernike polynomial. The aberration results can be used to evaluate the thermal effect on the correct lens assembly in the telescope system.

Multispectral Endoscopic Imaging of Colorectal Dysplasia In Vivo

Light provides a broad range of colors in the visible and near-infrared (400–900 nm) spectrum that can be used to transmit information about molecular expression in normal and diseased tissues. The absorbance spectrum of hemoglobin, the primary chromophore in tissue, is shown in Fig. 1A. Genetic changes that occur in cancer transformation can be heterogeneous, and several signaling pathways may be activated concurrently.1 Moreover, molecular activity levels may vary between individual patients, at different time points, and within the tumor. Thus, a single genetic mutation is unlikely to characterize most disease processes over a general population. Unfortunately, most endoscopic imaging methods are sensitive to only one molecular parameter.2 Thus, a methodology that can image multiple molecular targets simultaneously is better suited to address the heterogeneity of cancer and achieve disease detection with high sensitivity and specificity desired for efficient surveillance. In addition, these multiplexed strategies can potentially visualize the interactions between signaling pathways and allow for better understanding of disease pathogenesis on a systems level. Figure 1 A) The visible and near-infrared spectrum of light provides a broad range of colors to generate molecular images from digestive tract mucosa that can be collected with a B) 1.6 mm diameter multispectral scanning fiber endoscope. C) Excitation is delivered ... Recently, significant progress has been made in advancing new methods of endoscopic imaging to target disease in the digestive tract, including the development of novel instruments and specific contrast agents.3 In this video journal, we aim to demonstrate the application of a novel, multispectral endoscope that uses a scanning fiber to image multiple targets at the same time. Fluorescence imaging can be achieved with high target-to-background ratios, and allow us to see the different target expression patterns in an Apc-mutation dependent mouse model of spontaneous colorectal adenomas using multiple peptides as targeting ligands.4

Ensamblaje automático de piezas con desviaciones dimensionales

The automatic assembly of parts can create some problems because of the dimensional variations of the elements to be assembled (mainly because of mechanical inconsistencies). A representative example of this kind of assembly problem can be found in the production of vehicle headlamps, where one of the main stages is the assembly of the cover lens, which is made of polycarbonate, over a black housing made of polypropylene. This process is currently done statically and does not consider possible size variations of the plastic parts, thus resulting in headlamps with dimensional errors.This paper introduces a new methodology of dynamic assembly for an industrial application that requires an adaptive positioning of the parts that are to be assembled. In addition, this work presents a successful example of an industrial prototype where different technologies, which aim to solve different problems, have to be analysed and tested. In particular, different approaches were studied: surface measurement sensors for transparent and deformable objects, actuation systems that could modify the assembly position of the parts, and control algorithms that could carry out this adaptive assembly automatically. A robust industrial prototype for vehicle headlamp assembly has been designed and built. It has been validated in both a research lab and in the assembly line of a vehicle headlamp factory. The new prototype solves the problem of assembling vehicle headlamps, achieving a final product with minimum dimensional errors and offering an example of a solution to the problem of the assembly of pieces with dimensional errors.

Scene-based nonuniformity correction midwave infrared staring array triple field of view lens design

A high changeover ratio, triple field of view lens assembly was designed for limiting diffraction quality in the mid-wave infrared spectrum for a cryogenically cooled staring detector, and its switching mechanism is described. Three types of nonuniformity correction methods are evaluated using a nonsequential ray tracing method and their illumination uniformity performances are compared. Predicting the image formation of a specific target picture is realized through digital image processing and convolution algorithms.

Monte Carlo Model of Optomechanical Tolerance for Lens Assembly

Research on the opto-mechanical tolerance analysis for lens optical system is presented. Take a traditional "drop-in" assembly for example. How fabrication tolerances transfer to tolerances of optical elements is analysed. Finally, Monte-Carlo model for opto-mechanical tolerances is proposed, which considers both the fabrication and assembly process.

Fluorescence-based surface magnifying chromoendoscopy and optical coherence tomography endoscope.

A side-viewing, 2.3-mm diameter, surface magnifying chromoendoscopy-optical coherence tomography (SMC-OCT) endoscope has been designed for simultaneous, nondestructive surface fluorescence visualization and cross-sectional imaging. We apply this endoscope to in vivo examination of the mouse colon. A 30,000 element fiber bundle is combined with single mode fibers, for SMC and OCT imaging, respectively. The distal optics consist of a gradient-index lens and spacer to provide a 1× magnification at a working distance of 1.58 mm in air, necessary to image the sample through a 0.23-mm thick outer glass envelope, and an aluminized right-angle prism fixed to the distal end of the gradient-index lens assembly. The resulting 1∶1 imaging system is capable of 3.9-µm lateral and 2.3-µm axial resolution in the OCT channel, and 125-lp/mm resolution across a 0.70-mm field of view in the SMC channel. The endoscope can perform high contrast crypt visualization, molecular imaging, and cross-sectional imaging of colon microstructure.

Multifocal multiphoton endoscope

We report a miniaturized resonant/non-resonant multi-fiber raster scanner that is paired with a gradient-index lens assembly to achieve a compact and flexible multifocal multiphoton endoscope capable of longitudinal parallel image acquisition. Multiphoton images are obtained simultaneously at three axial depths, separated by ≥4.8 μm, by incorporating three axially offset double clad optical fibers into the miniaturized scanner. The fabricated endoscope has an outer diameter of 3 mm, a rigid length of 4 cm, and acquires images at 4 frames/s per focal plane, with lateral and axial resolutions for two-photon imaging of 0.8 and 10 μm, respectively.

In vivo imaging of unstained tissues using a compact and flexible multiphoton microendoscope

We use a compact and flexible multiphoton microendoscope (MPME) to acquire in vivo images of unstained liver, kidney, and colon from an anesthetized rat. The device delivers femtosecond pulsed 800 nm light from the core of a raster-scanned dual-clad fiber (DCF), which is focused by a miniaturized gradient-index lens assembly into tissue. Intrinsic fluorescence and second-harmonic generation signal from the tissue is epi-collected through the core and inner clad of the same DCF. The MPME has a rigid distal tip of 3 mm in outer diameter and 4 cm in length. The image field-of-view measures 115 μm by 115 μm and was acquired at 4.1 frames/s with 75 mW illumination power at the sample. Organs were imaged after anesthetizing Sprague-Dawley rats with isofluorane gas, accessing tissues via a ventral-midline abdominal incision, and isolating the organs with tongue depressors. In vivo multiphoton images acquired from liver, kidney, and colon using this device show features similar to that of conventional histology slides, without motion artifact, in ~75% of imaged frames. To the best of our knowledge, this is the first demonstration of multiphoton imaging of unstained tissue from a live subject using a compact and flexible MPME device.

Microbolometer imaging spectrometer

Newly developed, high-performance, long-wave- and mid-wave-IR Dyson spectrometers offer a compact, low-distortion, broadband, imaging spectrometer design. The design is further accentuated when coupled to microbolometer array technology. This novel coupling allows radiometric and spectral measurements of high-temperature targets. It also serves to be unique since it allows for the system to be aligned warm. This eliminates the need for cryogenic temperature cycling. Proof of concept results are shown for a spectrometer with a 7.5 to 12.0 μm spectral range and approximately 20 nm per spectral band (~200 bands). Results presented in this Letter show performance for remote hot targets (>200 °C) using an engineering grade spectrometer and IR commercial lens assembly.

主焦点式光学系统的光机结构设计与装调检测

Based on the prime focus optical system applied on the polaxis telescope,the primary mirror support design and analysis,the primary mirror alignment and test,corrective lens assembly design and alignment to system alignment and test were detailed discussed.The finite element method was used to analysis the primary mirror support,the centering facility was used to test the optic axis concentricity,and the collimator was used to test system image quality.A general method was obtained that is suitable for the prime focus optical system alignment and test.The primary mirror surface figure RMS is 0.0428λ after alignment,and the corrective lens assembly coaxial error achieves 12.4″.The energy centralization method was adopt to evaluate system image quality,and star point 80% energy concentrate degree was in 4×4 pixels on target area,which achieved design requirements.The results indicate system design is reasonable and alignment method is proper.This method also can be used to another prime focus optical system alignment and test.

Very low energy scanning electron microscopy in nanotechnology

The group of low energy electron microscopy at ISI AS CR in Brno has developed a methodology for very low energy scanning electron microscopy at high image resolution by means of an immersion electrostatic lens (the cathode lens) inserted between the illumination column of a conventional scanning electron microscope and the sample. In this way the microscope resolution can be preserved down to a landing energy of the electrons one or even fractions of an electronvolt. In the range of less than several tens of electronvolts the image signal generation processes include contrast mechanisms not met at higher energies, which respond to important features of the 3D inner potential of the target and visualise its local crystallinity as well as the electronic structure. The electron wavelength comparable with interatomic distances allows observation of various wave–optical phenomena in imaging. In addition, the cathode lens assembly secures acquisition of electrons backscattered from the sample at large angles with respect to the surface normal, which are abandoned in standard microscopes although they provide enhanced crystallinity information and surface sensitivity even at medium electron energies. The imaging method is described and illustrated with selected application examples.

Design of System for Rugged, Low-Noise Fiber-Optic Access to High-Temperature, High-Pressure Environments

This paper details a new design for fiber-optic access to harsh environments, with a particular focus on absorption spectroscopy in high-temperature, high-pressure combustion systems. A key component is a fiber-fused rod lens assembly which tolerates temperatures above 1100°C and enables simple optical access without interferences from etalons or ambient absorbers. The fibers, rod lenses, and supporting ports are designed to provide line-of-sight optical access without the need for adjustable optomechanics. Fiber modal noise was minimized by actively aligning a photodiode to the multimode fiber's output facet, resulting in a shot-noise-limited SNR of 53 000 for the system.

High-speed two-camera imaging pyrometer for mapping fireball temperatures

A high-speed imaging pyrometer was developed to investigate the behavior of flames and explosive events. The instrument consists of two monochrome high-speed Phantom v7.3 m cameras made by Vision Research Inc. arranged so that one lens assembly collects light for both cameras. The cameras are filtered at 700 or 900 nm with a 10 nm bandpass. The high irradiance produced by blackbody emission combined with variable shutter time and f-stop produces properly exposed images. The wavelengths were chosen with the expected temperatures in mind, and also to avoid any molecular or atomic gas phase emission. Temperatures measured using this pyrometer of exploded TNT charges are presented.