Light Illumination System Research Articles

Dynamic budget analysis of multiple parameters in a lithography system based on the superposition of light intensity fluctuations.

Lithography is one of the most critical processes in the manufacturing of micro- and nano-devices. As device critical dimensions continue to shrink, variations in system parameters during the lithography process often result in heavy deviations from the intended targets, making control of these parameters crucial to ensure that lithography results meet process requirements. Gaining a thorough comprehension of how various parameters interact and contribute to lithography errors is significant, and it is equally important to offer precise suggestions for managing these parameters in extreme ultraviolet lithography (EUVL) scanners. This paper analyzes the key physical factors in the light source, illumination system and projection system of EUVL scanners and proposes what we believe to be a new methodology of budget analysis utilizing the superposition of light intensity fluctuations. Then the corresponding characteristics of light intensity fluctuations are analyzed when these parameters have fluctuated through theoretical formula derivation. A mapping model was established between parameter fluctuations and imaging outcomes through the distribution of light intensity. The yield requirements for critical dimension and pattern shift in EUVL are used to determine the exact budget range for each parameter in the proposed methodology. By controlling the parameters according to the budget analysis method proposed in this paper, the deviation between the experimental results from the yield requirements is no more than 0.1% in average. This approach allows for dynamic updating of the control range of relevant parameters based on their distinct characteristics to accommodate the unique fingerprints of various EUVL scanners. Furthermore, based on this adaptive budget range of multiple parameters, it can offer distinct direction for the development of lithography equipment or serve as a clear indication for parameter monitoring.

A computer vision approach to improve maintenance automation for thermal power plants lubrication systems

PurposeLubricating oil leakage is a common issue in thermal power plant operation sites, requiring prompt equipment maintenance. The real-time detection of leakage occurrences could avoid disruptive consequences caused by the lack of timely maintenance. Currently, inspection operations are mostly carried out manually, resulting in time-consuming processes prone to health and safety hazards. To overcome such issues, this paper proposes a machine vision-based inspection system aimed at automating the oil leakage detection for improving the maintenance procedures.Design/methodology/approachThe approach aims at developing a novel modular-structured automatic inspection system. The image acquisition module collects digital images along a predefined inspection path using a dual-light (i.e. ultraviolet and blue light) illumination system, deploying the fluorescence of the lubricating oil while suppressing unwanted background noise. The image processing module is designed to detect the oil leakage within the digital images minimizing detection errors. A case study is reported to validate the industrial suitability of the proposed inspection system.FindingsOn-site experimental results demonstrate the capabilities to complete the automatic inspection procedures of the tested industrial equipment by achieving an oil leakage detection accuracy up to 99.13%.Practical implicationsThe proposed inspection system can be adopted in industrial context to detect lubricant leakage ensuring the equipment and the operators safety.Originality/valueThe proposed inspection system adopts a computer vision approach, which deploys the combination of two separate sources of light, to boost the detection capabilities, enabling the application for a variety of particularly hard-to-inspect industrial contexts.

Deep learning for precise axial localization of trapped microspheres in reflective optical systems.

High-precision axial localization measurement is an important part of micro-nanometer optical measurement, but there have been issues such as low calibration efficiency, poor accuracy, and cumbersome measurement, especially in reflected light illumination systems, where the lack of clarity of imaging details leads to the low accuracy of commonly used methods. Herein, we develop a trained residual neural network coupled with a convenient data acquisition strategy to address this challenge. Our method improves the axial localization precision of microspheres in both reflective illumination systems and transmission illumination systems. Using this new localization method, the reference position of the trapped microsphere can be extracted from the identification results, namely the "positioning point" among the experimental groups. This point relies on the unique signal characteristics of each sample measurement, eliminates systematic repeatability errors when performing identification across samples, and improves the localization precision of different samples. This method has been verified on both transmission and reflected illumination optical tweezers platforms. We will bring greater convenience to measurements in solution environments and will provide higher-order guarantees for force spectroscopy measurements in scenarios such as microsphere-based super-resolution microscopy and the surface mechanical properties of adherent flexible materials and cells.

Predesign of a projector alignment system for structured light illumination systems

Structured light illumination systems can measure a target’s two-dimensional height profile. Recent advancements in computational power and algorithms have enabled the predesign of optical systems where all experimental variables are determined prior to use in the laboratory. We present a predesign process to align the projector of a custom-structured light illumination system. The predesign method uses the native optical design file to simulate the residual aberrations and can perform a trade space analysis to tailor the alignment variables to desired preferences. The presented method can predict the experimental focus position to 1.6 μm root mean square over a broad range of physical settings.

Linearized projector alignment system for structured light illumination systems using the quad target method

Structured light illumination (SLI) systems can measure a target’s two-dimensional height profile. High-quality imaging in SLI systems is typically dependent upon well-focused optical systems that can be difficult to achieve due to the nonlinear nature of defocus. We present the quad target method (QTM), a simple and fast alignment technique that linearizes defocus for SLI projectors. This linear response provides a clear zero crossing along the optical axis to minimize any focus ambiguity and maximize projector focus quality. QTM creates the linearization by sampling the field at two locations along the optical axis using a quad target, which is a diffuse target with two different heights in opposing quadrants. To maximize feedback speed, QTM can estimate the current focus position using only a single image by measuring the contrast of projected sinusoidal fringes on the quad target. QTM was tested using a commercial SLI system and compared with a published phase shifting reconstruction technique. The nonlinear defocus behavior was efficiently linearized as evidenced by focus estimation accuracies over a broad range of QTM variables.

Phase-SLAM: Phase Based Simultaneous Localization and Mapping for Mobile Structured Light Illumination Systems

Structured Light Illumination (SLI) systems have been used for reliable indoor dense 3D scanning via phase triangulation. However, mobile SLI systems for 360 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> 3D reconstruction demand 3D point cloud registration, involving high computational complexity. In this letter, we propose a phase based Simultaneous Localization and Mapping (Phase-SLAM) framework for fast and accurate SLI sensor pose estimation and 3D object reconstruction. The novelty of this work is threefold: (1) developing a reprojection model from 3D points to 2D phase data towards phase registration with low computational complexity; (2) developing a local optimizer to achieve SLI sensor pose estimation (odometry) using the derived Jacobian matrix for the 6 DoF variables; (3) developing a compressive phase comparison method to achieve high-efficiency loop closure detection. The whole Phase-SLAM pipeline is then exploited using existing global pose graph optimization techniques. We build datasets from both the unreal simulation platform and a robotic arm based SLI system in real-world to verify the proposed approach. The experiment results demonstrate that the proposed Phase-SLAM outperforms other state-of-the-art methods in terms of the efficiency and accuracy of pose estimation and 3D reconstruction.

Development and Testing of a Modular Sunlight Transport System Employing Free-Form Mirrors

The energy consumption of artificial lighting and its impacts on health have stimulated research into natural lighting systems. However, natural lighting system designs are mainly custom, making them costly and difficult to replicate. This study took an office space as a testing field in order to develop a highly adaptable and adjustable modular natural light illumination system. We divided the system into multiple module designs, demonstrated the use of simple development and fabrication processes and integrated a freeform reflector into the system. In creating a freeform mirror, the optical simulation results of the tested field were regressed (through polynomial regression) to achieve a uniformly illuminated plane, and a high-efficiency light-emitting system was produced. Finally, an active heliostat was used to collect sunlight, combined with actual manufacturing verification and measurement results, in order to create an excellent indoor lighting system. As a result, we presented a low-cost and easy-to-design natural light illumination system for the assisted lighting of office areas.

Design of a reflective LED automotive headlamp lighting system based on a free-form surface.

In this paper, a design scheme of an automobile low-beam light illumination system with a reflector free-form surface is presented. Per the energy grid mapping theory and edge ray theory, an oblique triangular energy mapping scheme was proposed, and the free-form reflector was obtained by geometric iterative calculation. The Monte Carlo ray tracing method was used to simulate the system. The simulation results met the regulatory requirements of ECE R112, and the light efficiency could reach 81%. The length, width, and height of the reflector were 55.61mm×22.02mm×23.70mm. The reflector achieves a special light type through precise light distribution, does not need other shielding objects, and has the advantage of small size.

Total relighting

We propose a novel system for portrait relighting and background replacement, which maintains high-frequency boundary details and accurately synthesizes the subject's appearance as lit by novel illumination, thereby producing realistic composite images for any desired scene. Our technique includes foreground estimation via alpha matting, relighting, and compositing. We demonstrate that each of these stages can be tackled in a sequential pipeline without the use of priors (e.g. known background or known illumination) and with no specialized acquisition techniques, using only a single RGB portrait image and a novel, target HDR lighting environment as inputs. We train our model using relit portraits of subjects captured in a light stage computational illumination system, which records multiple lighting conditions, high quality geometry, and accurate alpha mattes. To perform realistic relighting for compositing, we introduce a novel per-pixel lighting representation in a deep learning framework, which explicitly models the diffuse and the specular components of appearance, producing relit portraits with convincingly rendered non-Lambertian effects like specular highlights. Multiple experiments and comparisons show the effectiveness of the proposed approach when applied to in-the-wild images.

Multiwell Combinatorial Hydrogel Array for High-Throughput Analysis of Cell-ECM Interactions.

Biophysical cues in the extracellular matrix (ECM) regulate cell behavior in a complex, nonlinear, and interdependent manner. To quantify these important regulatory relationships and gain a comprehensive understanding of mechanotransduction, there is a need for high-throughput matrix platforms that enable parallel culture and analysis of cells in various matrix conditions. Here we describe a multiwell hyaluronic acid (HA) platform in which cells are cultured on combinatorial arrays of hydrogels spanning a range of elasticities and adhesivities. Our strategy utilizes orthogonal photopatterning of stiffness and adhesivity gradients, with the stiffness gradient implemented by a programmable light illumination system. The resulting platform allows individual treatment and analysis of each matrix environment while eliminating contributions of haptotaxis and durotaxis. In human mesenchymal stem cells, our platform recapitulates expected relationships between matrix stiffness, adhesivity, and cell mechanosensing. We further applied the platform to show that as integrin ligand density falls, cell adhesion and migration depend more strongly on CD44-mediated interactions with the HA backbone. We anticipate that our system could bear great value for mechanistic discovery and screening where matrix mechanics and adhesivity are expected to influence phenotype.

System Transfer Function of Incoherent Light Illumination System

Generally, most imaging cases are incoherent light field illumination, and incoherent light illumination system has the advantages of simple installation and no coherent noise, therefore it has received extensive attention. The optical transfer function of illumination system is an effective method to evaluate the imaging quality of such optical system. In order to evaluate the imaging quality of an optical system, the specific form of the system transfer function should be known. However, due to the in-coherent nature of the optical field, both the input function and the impulse response can only be non-negative real functions, it is difficult to deal with lots of bipolar inputs and impulse responses. In this paper, two methods for calculating the system transfer function of incoherent light illumination system under quasi-monochromatic light illumination are given. Method 1: the coherence of incoherent light is defined, and the coherent system transfer function based on the characteristics of the system transfer itself is deduced. Method 2: based on the theory of partially coherent light, started from Kirchoff’s diffraction integral, the quasi-wavefront aberration is introduced, and the spatial coherence of the light field is described by the mutual intensity instead of the mutual coherent function, finally the system transfer function of incoherent illumination is derived. The calculation formula is simple and the transfer function of incoherent light system can be calculated accurately and easily. The work in this paper is helpful to the study of the new phenomena related to incoherent optical imaging.

PH-Dependent Water Clusters in Photoacid Solution: Real-Time Observation by ToF-SIMS at a Submicropore Confined Liquid-Vacuum Interface.

Water clusters are ubiquitously formed in aqueous solutions by hydrogen bonding, which is quite sensitive to various environment factors such as temperature, pressure, electrolytes, and pH. Investigation of how the environment has impact on water structure is important for further understanding of the nature of water and the interactions between water and solutes. In this work, pH-dependent water structure changes were studied by monitoring the changes for the size distribution of protonated water clusters by in-situ liquid ToF-SIMS. In combination with a light illumination system, in-situ liquid ToF-SIMS was used to real-time measure the changes of a light-activated organic photoacid under different light illumination conditions. Thus, the proton transfer and pH-mediated water cluster changes were analyzed in real-time. It was found that higher concentration of free protons could lead to a strengthened local hydrogen bonding network as well as relatively larger protonated water clusters in both organic acid and inorganic acid. Besides, the accumulation of protons at the liquid-vacuum interface under light illumination was observed owing to the affinity of organic molecules to the low-pressure gas phase. The application of in-situ liquid ToF-SIMS analysis in combination with in-situ light illumination system opened up an avenue to real-time investigate light-activated reactions. Besides, the results regarding water structure changes in acidic solutions showed important insights in related atmospheric and physiochemical processes.

Perovskite Photosensors Integrated with Silver Resonant‐Cavity Color Filters Display Color Perception Beyond That of the Human Eye

AbstractOrganic hybrid perovskite‐based photosensors generally display high responsivities and ultrafast response speeds, but their high dark currents with low detectivities have impeded their commercial applications. In this study, these problems are overcome by modifying the device structure and performing defect passivation of the perovskite. An inverted ITO/NiOx/perovskite/PCBM/BCP/Ag structure is applied to minimize the leakage current from the interlayers. In addition, a urea additive is embedded and the thickness of the perovskite layer is optimized, resulting in an ultralow dark current (&lt;2 pA), a peak detectivity of greater than 1.42 × 1014 Jones, and a high linear dynamic range (LDR) of up to 162 dB (in the response range from 20.25 to 6.80 × 10‐8 mW cm‐2). Using high‐purity color filters, combined with a well‐defined white light illumination system derived from a 3A solar simulator, the photosensitivity is evaluated under light of various hues and intensities (down to 10‐9 mW cm‐2). The optimized color sensors under blue, green, orange, and red hues of light display LDRs of greater than 139 dB in the mesopic vision regime (wavelengths: 400–700 nm) between 10‐6 and 10‐3 mW cm‐2—outperforming human visual color perception.

POWER SAVER STREET LIGHTING USING MICROCONTROLLER USING ATmega16

Street lights remain illuminated for whole nights and most of them used for lighting-up of highways are high energy consumption lamps. Preservation and sustainable use of energy and resources is an important factor of planning and development these days as Natural resources are depleting day by day, which pose a risk of scarcity and non-availability of the same for our presidenting generations. There is an acute need for devising a well thought out plan to prevent wastage of electricity. Perhaps, the government should think of implementing automatic street light control systems using LDR (light dependent resistor). This review paper illustrates the street light illumination system automated by the movement (frequency) of vehicles on that particular street. The crux of this paper is to emancipate the necessity and usage of street light control systems which combines various technologies is Timers, Photodiodes, Light Emitting Diodes (LED), and IR Sensors.

The hybrid lighting system with natural light and LED for tunnel lighting

The traditional tunnel lighting has the problem of poor lighting environment and huge energy consumption. This study uses natural light and LED as the light source to design two different lenses. When the natural light is sufficient, the natural light illumination system is used in the threshold zone and the exit zone, give tunnel lighting to reduce the number of LEDs used. When the natural light is insufficient, the sensor will detect the natural light level of the collimator exit to control the LED to compensate for the light or to illuminate the tunnel alone. In the two designs, the linear Fresnel lens is established by the Fresnel structure, and the free-form asymmetric lens of the LED is established by the catadioptric method. Finally, the model of the Hsueh-Shan tunnel was established by DIALux, and the two lenses were used simultaneously for mixed illumination to simulate average luminance, total uniformity, and longitudinal uniformity. The lens design reduces the influence of glare, and the design of the lamp spacing reduces the zebra pattern on the road surface. Combined with natural light and artificial light source, the tunnel light does not need to be 24 h of operation can save energy.

High-efficiency confocal paraboloids coupler design for natural light illumination systems

Recently, natural light illumination has become a hot topic in renewable energy research. Natural light illumination systems (NLISs) are used to guide sunlight for indoor illumination. The collector of NLISs is Lightbrick which consists of multi-prism. This paper proposes a novel design of confocal paraboloids couplers, which are important optical devices for NLISs. The coupler is designed with a prism optical structure and confocal paraboloids to collect a significant amount of inlet light from Lightbrick and compress it to one outlet light source. The prism structure causes the inlet light direction to coincide with a previous inlet light source, and the confocal paraboloid structure compresses two inlet light sources into one outlet. This newly designed confocal paraboloids coupler has high coupling efficiency, and its volume is smaller when the sunlight collection area is larger.

A freeform collimator lens design for the Natural Light Illumination System

This paper presents the design of a collimator lens for use with the Lightbrick that uses total internal reflection as well as convex and concave surfaces. The Lightbrick is a light collector for the Natural Light Illumination System. The collimator lens is constructed using freeform surfaces which can be calculated through geometric-optics. Verified by optical simulation, using the collimator lens can achieve 90.3% luminous flux within ±2°, and optical efficiency improves by 48% in the collimator lens output. The collimator lens converges the light distribution of the Lightbrick and enhances the transmission efficiency of the Natural Light Illumination System.

Active chromatically consistent hybrid light illumination system with natural light and light emitting diode for indoor lighting

This study investigates an active chromatically consistent hybrid light illumination system that combines the natural light with LEDs for indoor lighting. The hybrid light illumination system provides both natural light and LEDs from the hybrid light luminaire. Red, amber, green and blue, four different colors of high brightness LEDs are chose to compensate for the spectrum of natural light. The luminaire is used to redistribute the hybrid light to achieve stable and uniform illumination. The results show that natural light, LEDs and its hybrid light have similar luminous intensity distribution and belong to the type V. The maximum beam angle of the luminaire is limited to 53°. The hybrid light illumination system guarantees that the indoor final illumination spectrum matches the CCT of 5500 K and remains constant, thus ensuring chromaticity consistency. The illuminance of the test surface is mainly maintained at 300 lx and will increase to 330 lx at noon. By properly arranging the luminaires, the illuminance of the target surface will be very uniform. The performance of the hybrid light illumination system we designed meets the requirements and standards for indoor lighting.

Design of high-efficiency confocal paraboloid optical coupler for daylighting

A set of high-efficiency optical coupler design methods that can be used to collect multiple light sources for compression and integrate them into one light source outlet is proposed. It adopts parabolic confocal principle and high reflectivity coating and completes the structural design with the formulation concept. In addition to direct sunlight collection, the optical coupler is also coupled to the exit source of the collection subsystem of a natural light illumination system (NLIS). The concept of NLIS is to collect sunlight and direct it into indoor lighting. Due to the numerous light sources and the nonparallel light exiting from the light collection subsystem, it is inconvenient for space utilization and back-end transmission. Therefore, the actual NLIS structure is considered as a coupler to improve the efficiency of this design. The optical software used in this study was Fred. Finally, coupling 900 light sources still maintains 50.28% coupler efficiency. The results show that this optical coupler can provide perfect use in the application, and also solve the export problem, and finally achieve high coupler efficiency.

The Design and Comparison of Central and Distributed Light Sensored Smart LED Lighting Systems

There is a lack of published peer-reviewed research comparing the efficiencies of distributed versus central sensor-controlled LED lighting systems. This research proposes improving the smart illumination of a room with external fenestration using central and distributed light sensors. The optical and electrical measurements of the daylight have been made in the case where the light was not distributed evenly and not sufficient. Test results show that the proposed distributed light sensor illumination system has increased the efficiency by 28% when compared to the proposed central system. It has also been shown that the two tested systems are more cost-effective than common smart illumination systems.