Surface Light Source Research Articles

Multi-Enzyme Cascade Nanoreactors for High-Throughput Immunoassay: Transitioning Concept in Lab to Application in Community.

In this work, we reported a cholesterol oxidase (Chox)-loaded platinum (Pt) nanozyme with the collaborative cascade nanoreactor for the construction of nanozyme-enzyme-linked immunosorbent assay (N-ELSA) models to realize high-throughput rapid evaluation of cancer markers. Considering the high specific surface area and manipulable surface sites, ZIF-8 was used as a substrate for natural enzyme and nanozyme loading. The constructed ZIF-8-Pt nanozyme platform exhibited efficient enzyme-like catalytic efficiency with a standard corrected activity of 60.59 U mg-1, which was 12 times higher than that of the ZIF-8 precursor, and highly efficient photothermal conversion efficiency (∼35.49%). In N-ELISA testing, developed multienzyme photothermal probes were immobilized in microplates based on antigen-antibody-specific reactions. Cholesterol was reacted in a cascade to reactive oxygen radicals, which attacked 3,3',5,5'-tetramethylbenzidine, causing it to oxidize and color change, thus exhibiting highly enhanced efficient photothermal properties. Systematic temperature evaluations were performed by a hand-held microelectromechanical system thermal imager under the excitation of an 808 nm surface light source to determine the cancer antigen 15-3 (CA15-3) profiles in the samples. Encouragingly, the temperature signal from the microwells increased with increasing CA15-3, with a linear range of 2 mU mL-1 to 100 U mL-1, considering it to be the sensor with the widest working range for visualization and portability available. This work provides new horizons for the development of efficient multienzyme portable colorimetric-photothermal platforms to help advance the community-based process of early cancer detection.

Phase calculation of smooth surface with multi-reflectivity based on phase measurement deflectometry

With the continuous advancement of precision machining technology and the growing demand for products, increasingly complex objects with high reflectivity are becoming more prevalent in production and daily life. phase measurement deflectometry (PMD) is a technique that utilizes a surface light source to project structured light for comprehensive detection of highly reflective surfaces. It offers advantages such as high accuracy, fast speed, low cost, and non-contact operation. However, when the surface of the object being measured has varying levels of reflectivity, this method may produce errors due to significant differences in fringe contrast between different reflective areas. In order to enable the fringe deflection system to simultaneously detect multiple reflective objects without sacrificing accuracy, this paper proposes an adaptive method for fringe generation detection. This method can adaptively adjust the intensity based on the reflectivity of the measured surface and compensate for the light at the reflectivity boundary, ultimately achieving phase calculation for multiple reflective surfaces.

The effective use of focused shadowgraphy for single bubble nucleate pool boiling investigations

Nucleate pool boiling is known for its high heat transfer coefficients. Despite being widely implemented, the prediction of nucleate pool boiling mechanisms remains complex and single bubble heat transfer analysis is helpful to simplify the problem. Owing to the interesting bubble behaviour during nucleate pool boiling, publications tend to focus on the bubble dynamics while the experimental setup is only briefly discussed. Small but critical information on the experimental setup is often omitted, which makes it challenging or even impossible to reproduce or compare experimental data. Therefore, the purpose of this study is to provide a systematic approach to using focused shadowgraphy for the investigation of single bubble dynamics using R245fa. A pool boiling experimental setup has been built and equipped with temperature, pressure and heat flux sensors, as well as a high-speed camera and light source. The nucleate pool boiling takes place at a single cavity on a copper block. The influences of the heat transfer surface area, light source, and diffuser films were investigated to provide a systematic approach to the use of focused shadowgraphy for the investigation of single bubble dynamics.

Morphological and Position Factors of Vertical Surface Light Source Affecting Discomfort Glare Perception

Distinguished from conventional lighting, the LED vertical surface light source (VSLS) is directly exposed to human view, and the effects of which form it takes on visual perception are non-negligible. In the current discomfort glare evaluation system, the solid angle and the position index, which represent the relative relation between the glaring light source and human visual field, are not completely applicable for large-area VSLS, and hence are awaiting supplementation and modification. In this study, a physical experimental setup was established to conduct an evaluation experiment on discomfort glare, employing an LED display and white translucent frosted film to simulate vertical surface light sources (VSLS). The experiments were arranged with 21 VSLS shapes (comprising 3 areas and 7 length-to-width ratios) and 11 mounting positions. Subjective ratings and four eye-movement data parameters—namely, the change rate of pupil diameter (CRPD), mean saccadic amplitude (SA), blinking frequency (BF), and saccadic speed (SS)—were collected from 24 participants under each working condition using the Boyce Evaluation Scale and eye tracking techniques. The main results of this study are the following: (a) CRPD is the most appropriate eye-movement index for characterizing VSLS glare perception; (b) The area of the VSLS is the primary shape element influencing discomfort glare. Furthermore, with the same surface area, the lateral view angle (LaVA) and the longitudinal view angle (LoVA) perceived by the human eye also impact glare perception; (c) A functional equation between the VSLS area, LaVA, and LoVA to the borderline luminance between comfort and discomfort (BCD luminance) is fitted; (d) Based on the eccentric angle and the azimuthal angle, a modified position index P’ is proposed to represent the relative position of the VSLS in the visual field, and the ratio function of BCD luminance of the VSLS at non-central positions and the central position is fitted.

Sensitivity studies of nighttime top-of-atmosphere radiances from artificial light sources using a 3-D radiative transfer model for nighttime aerosol retrievals

Abstract. By accounting for surface-based light source emissions and top-of-atmosphere (TOA) downward lunar fluxes, we adapted the spherical harmonics discrete ordinate method (SHDOM) 3-dimensional (3-D) radiative transfer model (RTM) to simulate nighttime 3-D TOA radiances as observed from the Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) on board the Suomi-NPP satellite platform. Used previously for daytime 3-D applications, these new SHDOM enhancements allow for the study of the impacts of various observing conditions and aerosol properties on simulated VIIRS-DNB TOA radiances. Observations over Dakar, Senegal, selected for its bright city lights and a large range of aerosol optical depth (AOD), were investigated for potential applications and opportunities for using observed radiances containing VIIRS-DNB “bright pixels” from artificial light sources to conduct aerosol retrievals. We found that using the standard deviation (SD) of such bright pixels provided a more stable quantity for nighttime AOD retrievals than direct retrievals from TOA radiances. Further, both the mean TOA radiance and SD of TOA radiances over artificial sources are significantly impacted by satellite viewing angles. Light domes, the enhanced radiances adjacent to artificial light sources, are strong functions of aerosol properties and especially aerosol vertical distribution, which may be further utilized for retrieving aerosol layer height in future studies. Through inter-comparison with both day- and nighttime Aerosol Robotic Network (AERONET) data, the feasibility of retrieving nighttime AODs using 3-D RTM SHDOM over artificial light sources was demonstrated. Our study shows strong potential for using artificial light sources for nighttime AOD retrievals, while also highlighting larger uncertainties in quantifying surface light source emissions. This study underscores the need for surface light emission source characterizations as a key boundary condition, which is a complex task that requires enhanced input data and further research. We demonstrate how quality-controlled nighttime light data from the NASA's Black Marble product suite could serve as a primary input into estimations of surface light source emissions for nighttime aerosol retrievals.

Spatial position recognition method of semi-transparent and flexible workpieces: A machine vision based on red light assisted

In the automatic sorting process, overlapping translucent and flexible workpieces on the conveyor belt, blurring the imaging edge features of translucent and flexible workpieces is a challenge to locate the upper and lower workpieces spatially, we propose a method for locating translucent and flexible workpieces spatially under the overlapping environment in conjunction with the most common automatic sorting of translucent and flexible workpieces such as infusion tube drip buckets. Firstly, we propose a rectangular surface light source based on 650 nm band and monocular CCD for imaging translucent workpieces such as infusion tube drip buckets and optimize the imaging parameters. Secondly, we study a feature matching recognition algorithm for flexible workpieces that are prone to deformation, construct a mapping relationship between the position of overlapping layers and imaging quality of translucent and flexible workpieces such as infusion tube drip buckets based on clarity and information entropy, and establish The mapping relationship between the position of the overlapping layers and the imaging quality of translucent and flexible workpieces such as infusion tube drip buckets is constructed based on clarity and information entropy, and a local spatial coordinate conversion model is established. Finally, the spatial positioning coordinates of overlapping and non-overlapping translucent and flexible workpieces in the local coordinate system are identified, and the results show that the imaging method and theory can be effectively applied to the identification of overlapping and spatial positioning coordinates in the automatic sorting of translucent workpieces such as infusion tube drip buckets.

20.2: 2D/3D Mixed Display Based on Polarization Division Multiplexing

We propose a two‐dimensional (2D)/ three‐dimensional (3D) mixed display system based on polarization division multiplexing. The polarization division multiplexing device is composed of a polarization switching layer, a polarization‐dependent liquid crystal micro‐lens array (LCMLA) and a scattering polarizer. According to the polarization state of incident light switched by the polarization switching layer, the combined action of polarization‐dependent LCMLA and scattering polarizer can form both point light source array for 3D display and scattered light source for 2D display. The 2D/3D mixed images can be reconstructed through the precise control of the polarization direction of each pixel. The advantage of the proposed system is that a point light source array and a surface light source are formed only by adjusting the state of the polarization switching layer. What's more, our proposed system has low driving voltage and relatively compact system volume.

Wide-Angle Mini-Light-Emitting Diodes without Optical Lens for an Ultrathin Flexible Light Source.

This report outlines a proposed method of packaging wide-angle (WA) mini-light-emitting diode (mini-LED) devices without optical lenses to create a highly efficient, ultrathin, flexible planar backlight for portable quantum dot light-emitting diode (QLED) displays. Since the luminous intensity curve for mini-LEDs generally recommends a beam angle of 120°, numerous LEDs are necessary to achieve a uniform surface light source for a QLED backlight. The light-guide layer and diffusion layer were packaged together on a chip surface to create WA mini-LEDs with a viewing angle of 180°. These chips were then combined with a quantum dot (QD) film and an optical film to create a high-efficiency, ultrathin, flexible planar light source with excellent color purity that can be used as a QLED display backlight. A 6 in (14.4 cm) light source was used as an experimental sample. When 1.44 W was supplied to the sample, the 3200-piece WA mini-LED with a flexible planar QLED display had a beam angle of 180° on the luminous intensity curve, a planar backlight thickness of 0.98 mm, a luminance of 10,322 nits, and a luminance uniformity of 92%.

Experimental Study of Frequency Control of LaSMP Laminated Beams

AbstractLight-activated shape memory polymers (LaSMPs) exhibit stiffness variations when exposed to ultraviolet (UV) lights. Thus, LaSMP could manipulate structural frequencies with UV light exposures when laminated on structures. This study aims to experimentally demonstrate the effectiveness of LaSMP frequency control of a flexible beam. The natural frequency of a three-layered Euler–Bernoulli beam composed of LaSMP, adhesive tape, and the flexible beam is analyzed and its frequency formulation exhibits the LaSMP stiffness influence. Since the LaSMP adopted in this study is a new spiropyran-based composition—Sp3/EVA_4, a generic Young’s modulus model is proposed and then simplified to model this new LaSMP composition. To guarantee a homogenous light field, light intensities on the UV surface light source at different positions are tested. The temperature change of the LaSMP sample under UV exposures is also measured. The time constant and the threshold intensity of the reverse reaction are measured. LaSMP Young’s modulus variation is tested with a uniaxial tension experiment. The constitutive model of LaSMP’s Young’s modulus is validated by experimental data. With these preparations, the LaSMP laminated flexible beam model is exposed to UV lights and its natural frequencies are identified with data acquisition and analysis system. Then, natural frequency variations of 25%, 50%, 75%, to 100% exposure areas are also evaluated. The maximum natural frequency variation ratio achieves 9.7%; theoretical predictions and experimental data of LaSMP natural frequency control are compared very well.

Enhancement of Luminous Intensity Emission from Incoherent LED Light Sources within the Detection Angle of 10° Using Metalenses.

In this work, we present metalenses (MLs) designed to enhance the luminous intensity of incoherent light-emitting diodes (LEDs) within the detection angles of 0° and 10°. The detection angle of 0° refers to the center of the LED. Because the light emitted from LEDs is incoherent and expressed as a surface light source, they are numerically described as a set of point sources and calculated using incoherent summation. The titanium dioxide (TiO2) and amorphous silicon (a-Si) nanohole meta-atoms are designed; however, the full 2π phase coverage is not reached. Nevertheless, because the phase modulation at the edge of the ML is important, an ML is successfully designed. The typical phase profile of the ML enhances the luminous intensity at the center, and the phase profile is modified to increase the luminous intensity in the target detection angle region. Far field simulations are conducted to calculate the luminous intensity after 25 m of propagation. We demonstrate an enhancement of the luminous intensity at the center by 8551% and 2115% using TiO2 and a-Si MLs, respectively. Meanwhile, the TiO2 and a-Si MLs with the modified phase profiles enhance the luminous intensity within the detection angle of 10° by 263% and 30%, respectively.

Measurement error model of the bio-inspired polarization imaging orientation sensor.

This article studies the measurement error model and calibration method of the bio-inspired polarization imaging orientation sensor (BPIOS), which has important engineering significance for promoting bio-inspired polarization navigation. Firstly, we systematically analyzed the measurement errors in the imaging process of polarized skylight and accurately established an error model of BPIOS based on Stokes vector. Secondly, using the simulated Rayleigh skylight as the incident surface light source, the influence of multi-source factors on the measurement accuracy of BPIOS is quantitatively given for the first time. These simulation results can guide the later calibration of BPIOS. We then proposed a calibration method of BPIOS based on geometric parameters and the Mueller matrix of the optical system and conducted an indoor calibration experiment. Experimental results show that the measurement accuracy of the calibrated BPIOS can reach 0.136°. Finally, the outdoor performance of BPIOS is studied. Outdoor dynamic performance test and field compensation were performed. Outdoor results show that the heading accuracy of BPIOS is 0.667°.

Quantitative pH Determination Based on the Dominant Wavelength Analysis of Commercial Test Strips

The determination of pH values is essential in many chemical, medical, and environmental monitoring processes, which has been relying on conventional pH meters (glass electrodes) for quantitation and pH test strips for qualitative (or semi-quantitative) assessment. In this work, we demonstrate a smartphone-based pH determination technique, which performs digital image analysis of commercial test strips, particularly the determination of either the dominant wavelength (λd) or complementary wavelength (λc) of the color image. In conjunction with a 3D-printed optical accessory (with a surface light source and a macro lens), the quality of captured images have been warranted, and the quantitation accuracy of 0.05 pH units has been achieved. More importantly, the performance of this smartphone-based pH reading system (namely "Smart-pH-Reader") was validated using multiple real-world samples, as the results are consistent with those determined with a standard pH meter. The Smart-pH-Reader is envisioned to be a simple, portable, and accurate tool for pH determination in the fields of environmental monitoring, medical diagnosis, and beyond.

Study on information content of light field on the object surface under various coherent states illumination

A novel approach for the measurement of information content of light field on the object surface illuminated by various coherent states source based on the statistical optics theory and Shannon’s information theory has been proposed. Firstly, we propose that the information content of light field on the object surface can be regarded as the product of the spacial freedom degrees of the object surface itself and that of the illuminating light field arriving at the object surface. Then, calculate the distribution of complex degree of coherence on the object surface under various coherent states illumination and then obtain the number of uncorrelated areas of light field on the object surface which can be used to determine the number of freedom degree of the light field. At the same time, taking into account the structure of the object itself, the freedom degree of the light field on the object surface in completely coherent, partially coherent and incoherent illumination are derived respectively.The specific algorithms for the information content of the light field illuminated by a 1D linear incoherent light source and uniform quasi monochromatic incoherent surface light source with arbitrary shape are also presented.

P‐52: Realization of Transparent LCD with Field Sequence

A 2.6‐inch Transparent LCD prototype has been developed by using network polymer liquid crystal PNLC (Polymer Network Liquid Crystal) combined with field‐sequential color display technology. Moreover, the display principle of transparent LCD with field sequence was expounded and a contrast ratio enhancement algorithm has been developed to improve the image CR in this paper. As there is an intrinsic problem for the transparent LCD with field sequence that uniformity of brightness is not excellent enough caused by the panel polymer and the side‐in backlight, a novel light‐guiding structure has been developed to provide the uniform surface light source, the picture shows better effect than the traditional processing method which achieved high efficiency light emission (83%) and uniformity (64%). The simulation and experimental results verify the effectiveness of the contrast ratio enhancement algorithm and the novel light‐guiding structure.

Robust and High-Precision Vision System for Deflection Measurement of Crane Girder With Camera Shake Reduction

Crane girder is subject to alternating load in long time, which makes it prone to fatigue and fracture. Vision deflection measurement has become an effective method for structural health monitoring. However, crane girder does not always exhibit high contrast feature and artificial markers have to be pasted. Existing artificial markers cannot perform well in poor light conditions and the accuracy is limited. In this paper, we design an anti-interference marker by pasting a film onto a circular surface light source. The marker allows the vision system to work well under different light conditions. In addition, the reduction of camera shake and sub-pixel technique have been studied to improve the accuracy. According to the characteristics of the marker, corresponding image processing algorithms are also studied. Firstly, the designed marker can suppress environmental interference even at long distances with a wireless module and a small aperture. Secondly, the center of the marker in the image can be calculated using a sub-pixel detection technique. Finally, a camera shake reduction method is applied by using multiple reference markers and scale conversion factors are taken into account to get the physical displacement. To verify the measurement results, two experiments were carried out using a digital dial gauge sensor and laser displacement sensor for comparison. The experimental results proved the robustness and high precision of the vision system.

White Light Realization and Color Coordinate Calculation of OLED Devices

White-light OLED devices can be used as a surface light source and for full color displays,which have become the focus of OLED research and development.However,there are some shortcomings in the realization of white-light OLED devices,such as insufficient luminous performance,difficult process control,and easy color drift.To solve these problems,the optimized ratios of primary colors(red,green,and blue)of organic OLED devices were preliminarily obtained through the realization of white light and calculation of the color coordinate.An experimental white-light OLED device was prepared with a color coordinate of(0.31,0.35).Further,theoretical calculations and experimental optimizations were carried out to reduce the red-light doping concentration and increase the green-light doping ratio to realize standard white-light(0.33,0.33)OLED devices.

P‐207: Late‐News‐Poster: Infrared Down‐conversion of Organic Light Emitting Diode Emission for Medical Use and Vein Authentication

A flexible infrared surface light source is fabricated for medical and vein authentication purpose. The light source is composed of red‐emissive OLED device and infrared down‐conversion film covering the red OLED. The light source exhibits the emission wavelength between 700‐1000 nm, and provides enough radiances for medical and authentication system at voltage below 4V. A vein authentication prototype was fabricated for comparison between conventional LEDs and down‐converted OLEDs. The peak wavelength for the prototype is 834 nm and the radiant flux at the wavelength is 2.7‐6.0 mW using the 15x15‐mm2 OLED panel. Testing result clearly shows the merit of surface light source in terms of authentication accuracy, especially for false rejection rate.

Phototaxis Motion Behavior of a Self‐propelled Submarine‐like Water Droplet Robot in Oil Solvent

AbstractControllable self‐propelled droplet robots show great potential to be used as carriers, sensors and actuators in biological medicine and oil exploration. Current research mainly focuses on studying oil droplet robots floating in water phase which has limited application. Different from the previous robots, a light‐driven self‐propelled water‐phase droplet micro robot, which is doped with Fe2O3 nanoparticles, moving in oil solvent is proposed. Unlike light‐driven oil droplets, the water drop robot is constantly diving towards the light source like a submarine moving in oil environment under blue laser irradiation. Numerical simulations are performed to investigate the water/oil interface behavior and the motion mechanism of micro robots. It is found that a photocatalytic Fenton reaction occurs on the irradiated Fe2O3 nanoparticles of water droplet robot, which causes uneven ion concentration to change the interfacial tension distribution of the water drop generating Marangoni flow. In addition to phototaxis behavior, further experiments confirmed that multiple water droplet micro robots show collective behavior under the control of surface light source. The proposed water droplet micro robot provides new possibilities for the development of targeted drug delivery, oil‐water separation as well as oil pollution treatment.

Flexible but Mechanically Robust Hazy Quantum Dot/Glass Fiber Reinforced Film for Efficiently Luminescent Surface Light Source

AbstractColor conversion films with haze have aroused interest for use in surface light sources for display and lighting applications. Surface patterning or addition of light scattering particles to the color‐conversion film induces haze and consequently, improves the photoluminescence (PL) extraction. Herein, a CdSe/CdZnS quantum dots (QDs)‐embedded glass fiber reinforced siloxane hybrid (QD‐GFRH) film with high haze value is demonstrated, originating from refractive index mismatch between glass fiber and methacrylate‐phenyl functionalized siloxane matrix. The hazy QD‐GFRH film shows a twofold improvement in PL extraction, as well as robust mechanical properties, such as low thermal expansion (13 × 10−6 K−1) and high deformation resistance (E = 11.8 GPa), compared to conventional polymers. Because QDs are chemically dispersed inside the film by covalent crosslinking with siloxane matrix, the QD‐GFRH film exhibits long‐term (30 days) thermal and chemical stability against heat and moisture conditions [85 °C/5% relative humidity (RH), and 85 °C/85% RH]. Furthermore, the yellow photoemissive QD‐GFRH film, with a smooth surface and large scale (A4 size, 210 mm × 297 mm size), is applied as a color‐conversion film on a blue light‐emitting diode and it covers a large color gamut (107% relative to National Television System Committee).

A low-light radiative transfer model for satellite observations of moonlight and earth surface light at night

Lunar sun-reflected light can be effectively measured through a low-light band or a day/night band (DNB) implemented on space-based optical sensors. Based on moonlight, nocturnal observations for artificial light sources at night can be achieved. However, to date, an open-sourced and mature Low-Light Radiative Transfer Model (LLRTM) for the further understanding of the radiative transfer problem at night is still unavailable. Therefore, this study develops a new LLRTM at night with the correction of the lunar and active surface light sources. First, the radiative transfer equations with an active surface light source are derived for the calculation based on the lunar spectral irradiance (LSI) model. The simulation from this new LLRTM shows a minimal bias when compared with the discrete ordinates radiative transfer (DISORT) model. The simulated results of radiance and reflectance at the top of the atmosphere (TOA) also show that the surface light source has a remarkable impact on the radiative transfer process. In contrast, the change in the lunar phase angle has minimal influence. Also, comparing with space-based DNB radiance observations, LLRTM shows the potential to simulate space-based low-light imager observations under an effective surface light source condition during the night.