Lens Mount Research Articles

Taguchi–gray relational analysis of eccentricity and tilt of multilens module mount fabricated by injection compression molding

AbstractThis study utilizes the mold flow analysis technique of the injection compression molding (ICM) process, combined with the Taguchi–gray relational analysis (GRA), for process optimization analysis on the roundness of the lens holes and the flatness of the lens mount in a 4 × 4 planar multilens array mount. After manufacturing simulation analysis, the eccentricity and tilt information of the lens mount was further evaluated optically through spot diagram analysis upon inserting the same glass lenses. The results showed a positive correlation trend between roundness and flatness in structural deformation analysis, indicating that improving the overall flatness of the lens mount can enhance the roundness of the lens holes. In optical analysis, better improvements in the lens tilt angle were achieved through GRA. In conclusion, aiming to simultaneously improve the roundness of the lens holes and the overall flatness of the lens mount, the Taguchi–GRA method can achieve the optimization objectives. In terms of optical performance, by optimizing for roundness, it is possible not only to reduce the diameter of the light spot but also to simultaneously reduce the offset displacement of the light spot center on the screen. The method proposed in this paper can serve as an analytical model for the design and fabrication of plastic multilens mount.

Decoupling Degradations with Recurrent Network for Video Restoration in Under-Display Camera

Under-display camera (UDC) systems are the foundation of full-screen display devices in which the lens mounts under the display. The pixel array of light-emitting diodes used for display diffracts and attenuates incident light, causing various degradations as the light intensity changes. Unlike general video restoration which recovers video by treating different degradation factors equally, video restoration for UDC systems is more challenging that concerns removing diverse degradation over time while preserving temporal consistency. In this paper, we introduce a novel video restoration network, called D2RNet, specifically designed for UDC systems. It employs a set of Decoupling Attention Modules (DAM) that effectively separate the various video degradation factors. More specifically, a soft mask generation function is proposed to formulate each frame into flare and haze based on the diffraction arising from incident light of different intensities, followed by the proposed flare and haze removal components that leverage long- and short-term feature learning to handle the respective degradations. Such a design offers an targeted and effective solution to eliminating various types of degradation in UDC systems. We further extend our design into multi-scale to overcome the scale-changing of degradation that often occur in long-range videos. To demonstrate the superiority of D2RNet, we propose a large-scale UDC video benchmark by gathering HDR videos and generating realistically degraded videos using the point spread function measured by a commercial UDC system. Extensive quantitative and qualitative evaluations demonstrate the superiority of D2RNet compared to other state-of-the-art video restoration and UDC image restoration methods.

Integrative Transcriptome and Proteome Analyses Elucidate the Mechanism of Lens-Induced Myopia in Mice.

The purpose of this study was to investigate the underlying molecular mechanism of lens-induced myopia (LIM) through transcriptome and proteome analyses with a modified mouse myopia model. Four-week-old C57BL/6J mice were treated with a homemade newly designed -25 diopter (D) lens mounting by a 3D printing pen before right eyes for 4 weeks. Refraction (RE) and axial dimensions were measured every 2 weeks. Retinas were analyzed by RNA-sequencing and data-independent acquisition liquid chromatography tandem mass spectrometry. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation, and STRING databases were used to identify significantly affected pathways in transcriptomic and proteomic data sets. Western blot was used to detect the expression of specific proteins. The modified model was accessible and efficient. Mice displayed a significant myopic shift (approximately 8 D) following 4 weeks' of lens treatment. Through transcriptomics and proteomics analysis, we elucidated 175 differently expressed genes (DEGs) and 646 differentially expressed proteins (DEPs) between binoculus. The transcriptomic and proteomic data showed a low correlation. Going over the mRNA protein matches, insulin like growth factor 2 mRNA binding protein 1 (Igf2bp1) was found to be a convincing biomarker of LIM, which was confirmed by Western blot. RNA-seq and proteome profiling confirmed that these two "omics" data sets complemented one another in KEGG pathways annovation. Among these, metabolic and human diseases pathways were considered to be correlated with the LIM forming process. The newly constructed LIM model provides a useful tool for future myopia research. Combining transcriptomic and proteomic analysis may potentially brighten the prospects of novel therapeutic targets for patients with myopia.

Inkjet-printed freeform gradient refractive index Alvarez-Lohmann optics for vision correction in respiratory masks

Inkjet-print additive manufactured freeform gradient refractive index representations of an Alvarez-Lohmann lens were developed and optimized for use in vision-correction inserts for respiratory masks. A series of planar 30-mm by 20-mm Alvarez-Lohmann lens pair were printed and characterized. Select lens pairs were mounted with printed mechanical lens mounts and translation guides optimized for vision correction. Metrology showed accurate reproduction of the cubic refractive phase functions. Tests matching simulated performance showed a large diopter adjustment over a large eyebox and a wide gaze angle. The printed optics were environmentally tested and then mounted in a respiratory mask and demonstrated with glove-accessible control electronics. The performance demonstrates the benefits of using printed three-dimensional freeform gradient index optics for implementing complex refractive optical functions for challenging applications including artificial and virtual reality systems.

Motion improvised miniaturized dual focus lens module based on piezoelectric actuator for the medical applications

In this work, we have designed a miniaturized dual focus module using a piezo-electric actuator for application in mobile. The device mainly consists of two lens mounts for holding the Alvarez-Lohmann lens. One of the lens mounts is stationary while another is rotated with the help of a piezoelectric actuator. The materials used for the development of the device are combinations of aluminum for chassis and lead zirconate titanate as piezo material for actuator. The movement of the actuator tip is an elliptical shape which used to facilitate the force to the lens. Mainly the mathematical modeling and finite element simulation of the device are carried out using COMSOL Multiphysics. The actuator rotates the mounted lens for 0.12° in one elliptical cycle at the applied voltage of 100 V with the resonance frequency. The device has a scope of applications in medical equipment such as a 3 D camera which is required mainly for disease diagnosis and medical operation purposes.

Stereo PIV measurement of diffuser swirling flow

The swirling flow in a diffuser has been studied using the stereo PIV technique. The DANTEC hardware and software were used for the experiment. The water pipe flow in the diffuser inlet has been set spinning by introducing tangential jet flow. Both piping and diffuser were of circular cross-section, however diffuser casing had rectangular (square) cross-section. The plane of measurement was located perpendicular to the flow within the diffuser. The two cameras with the Scheinpflug lens mounting were used, however the angle between the lenses axes and the diffuser outer surface was far from to be perpendicular, as recommended in similar situations. This configuration has been dictated by technical conditions in the laboratory. The two-level calibration target with dots was used for the cameras calibration. The calibration covers the diffusers central region in a good quality, however regions close to the walls were not well resolved. Many combinations of axial and tangential inflow conditions have been studied. The acquisition covered about 3 seconds in real time with frequency 500 Hz. Both statistics and dynamics of the flow have been studied in details. Results are shown for both statistical characteristics and dynamical analysis of various conditions. During experiments the air-glass-water interface was not normal to the camera viewing axis. The discussion how to solve this problem and of the bias of the calibration will be introduced.

Manufacturing and assembly of an all-glass OCT microendoscope

We present a forward-looking, fiber-scanning endomicroscope designed for optical coherence tomography (OCT) and OCT-Angiography (OCT-A) imaging through the working channel of commercial gastrointestinal endoscopes and cystoscopes. 3.4 mm in outer diameter and 11.9 mm in length, the probe is capable of high-resolution volumetric imaging with a field-of-view of up to 2.6 mm and an imaging depth of up to 1.5 mm at a lateral resolution of 19 µm. A high-precision lens mount fabricated in fused silica using selective laser-induced etching (SLE) allows the tailoring of the optical performance for different imaging requirements. A glass structure fabricated by the same method encapsulates the optical and mechanical components, providing ease of assembly and alignment accuracy. The concept can be adapted to high resolution OCT/-A imaging of various organs, particularly in the gastrointestinal tract and bladder.

Stereo digital image correlation with improved depth of field using tilt-shift photography

Stereo digital image correlation (DIC) is a non-contacting technique to obtain full-field displacement and strain fields from the surface of a deforming object by comparing images recorded before and after deformation. With stereo measurement techniques, out-of-plane measurements are often limited by the depth of field achieved in an image. Tilt-shift photography uses the Scheimpflug principle to improve depth of field by rotating the image plane with respect to the camera sensor. This is implemented using a tilt-shift lens mount, which imposes an angle of tilt between the lens and the camera sensor. In this stereo-DIC study, images were taken using a range of stereo camera angles with either the lens tilted or not tilted to impose the Scheimpflug effect. A series of rigid body displacements were then measured for each combination of stereo and tilt angles. An evaluation of the means and standard deviations of the measurements shows that Scheimpflug adjustment offers minimal improvement when measuring rigid body displacements, but significant improvement at reducing artificial strains.

A New Solving Method of the Athermal Bonding Thickness in Lens Mount

Adhesives are widely used in the design of optical and mechanical structures. For optics fixed by adhesive bonding, the mismatch of the thermal expansion coefficient of the materials among the lens, the adhesive layer and the frame will bring thermal stress in the radial direction of the lens, which will affect the imaging of entire optical system. Studies have shown that by changing the thickness of the adhesive layer can reduce or even eliminate the radial stress caused by temperature changes, so it is critical to obtain the thickness with low(zero) radial stress. Based on the derivation of the existing athermal bond thickness equation, this paper proposes a new bonding layer constraint condition assumption, introduces the thermal expansion coefficient scale factors k1, k2, and derives a novel athermal bond thickness equation. Then, using the finite element method, the thermal stress simulation analysis of two adhesive lens assemblies with different count materials is solved, by comparing the simulated value with the analytical solutions, it’s found that the errors of both are within 10%, which shows that the newly derived equation has sufficient accuracy to meet the needs of engineering application.

Methods to achieve fast, accurate, and mechanically robust optical breadboard alignment

Typical laboratory optical systems use commercially off-the-shelf components in which emphasis is oriented toward ease of assembly and a wide range of adjustability. However, these mounts often require individual alignments that, when each degree of adjustability is cumulated in a complex optical system, can be inefficient and time consuming. Furthermore, most of these optomechanical mounts lack the mechanical robustness required to maintain operational performances out of the laboratory environment. An optomechanical assembly method based on passively aligning design features is proposed to simplify breadboard level optical systems, to improve alignment accuracy and maintaining operational pointing stability. Given the recent improvements in lens passive centering techniques, it seemed worth exploring methods to reduce alignment time and improve the mechanical robustness of laboratory setups. Recent studies show that a typical optical lens centering of <1 arc min with respect to its mount can be achieved using patented auto centering and edge contact mounting technologies. To achieve similar position accuracy between multiple lenses on a portable breadboard, lens mounts should be designed and built with proper reference surfaces and a system should easily reference one mount with respect to the other. The use of reference spheres and dedicated optomechanical mounts is employed to leverage the standard threaded holes of laboratory breadboards and achieve precise lens mount positioning. A series of optomechanical mounts incorporating these techniques are therefore tested. Position accuracy and repeatability are measured mechanically with a coordinate measuring machine and optically with the active monitoring of a laser beam centroid position. Measured position accuracy at the optomechanical mount level is <50 μm with a repeatability of less than 5 μm per interface. The optomechanical mounts robustness is tested within typical storage temperature range of −46 ° C to 63°C and at vibrations levels exceeding typical shipping conditions. Measured optical pointing stability of a simple optical system after environmental testing was found to be under 25 μm. This method should be a promising solution to bridge the design technological gap between the early prototyping and the production phases.

High accuracy lens centering using edge contact mounting

We introduce a new type of drop-in technique used to passively and accurately center lenses in optical mounts. This lens mounting method is called edge contact mounting and uses the edge at the intersection of the cylindrical and optical surface of the lens as the mounting interface. By providing a spherical mounting seat for the lens on a simple standard threaded ring, it is possible to center accurately lenses of different geometries, diameters, and radius of curvatures. The method allows relaxation of some manufacturing tolerances compared with rim contact drop-in and is not subject to a minimum clamping angle as for the surface contact mounting. This innovative lens mounting method allows extension of the centering accuracy offered by passive lens centering methods to a next level without compromise on cost and complexity.

PENGGUNAAN TEKNIK REVERSE LENS DALAM PEMOTRETAN FOTOGRAFI MAKRO

Something that we don't normally see whether because of something we rarely find or indeed we often find, but we pay less attention in depth because it might be of a size that is too small so it doesn't 'steal' our attention. Large and clear details are common when we observe things, especially objects around us. Butwhat if we want something that is more and less exposed because of its small size. Many simple things are used such as by bringing our eyes closer to the object to use tools such as a magnifying glass or even a microscope if it is needed. Raising a small subject is actually not unusual in the world of photography. The term photography in photography is called macro photography, which is shooting with small objects or subjects with the help of lenses or special tools so that the small-looking subject will appear large and the details of the subject will be unclear. For some people photography equipment might be considered expensive compared to mobile phones that have been equipped with cameras, especially when discussing equipment related to macro photography. Basically, macro shooting is the same as ordinary shooting, but the lens andsupporting equipment are slightly different. Especially lenses that do require a macro lens that has a tight focal point and are relatively expensive in price. But now there are many different converters for macro photography that are mounted on a normal lens, although the quality will indeed be different when we use an actual macro lens. In this study the author will put more emphasis on macro photography using the Reverse Lens technique. Reverse Lens is a technique by reversing the normal lens position and attaching it to the camera body mounting. Because reversing the lens mount requires an adapter so that it can be installed in the camera body so the shooting process will be more comfortable. Hopefully this research can provide useful results and interesting photography.

Optomechanical design and simulation of a cryogenic infrared spectrometer.

To continuously monitor, identify, and classify a wide range of areas all day and satisfy the hyperspectral remote sensing requirements in disaster reduction, environment, agriculture, forestry, marine, and resource areas, the authors participated in a pre-research program for full spectrum hyperspectral detection in geostationary orbit. As part of the program, the authors designed a cryogenic infrared spectrometer working at the diffraction limit. Such spectrometer complied with prism dispersion, exhibiting a 120 mm long slit, 2.5-5 µm band range, and 50 nm minimum spectral resolution. The spectrometer should overtake a temperature variation of 143 K for its assembly temperature at 293 K and the working temperature at 150 K. Low-temperature invar and carbon fiber were adopted as the framework material. The spectrometer was composed of two reflective Zerodur mirrors and one CaF2 Fery prism. Compensation mounts were developed for the reflective mirrors, while a spring-loaded autocentering cryogenic lens mount was designed for a CaF2 prism. CaF2 material exhibits a large linear expansion coefficient, making its mount difficult to design. The alignment requirements of the system were described, and the calculations that ensure the lenses undergo both appropriate stresses and temperature differences were presented. Structural thermal optical performance analysis was also conducted to assess the degradation in optical performance caused by temperature variation to verify the overall optomechanical design.

Optomechanical optimal design configuration and analysis of glue pad bonds in lens mounting for space application

Optomechanical systems are very complex requiring a high degree of accuracy. The carrier structure of an optical system is required to maintain the position of the optical components with respect to each other within the design tolerances. The most common loads on optical systems are self-weight, due to gravity orientations, and temperature ranges, due to exposure to rapidly changing temperatures from very cold to very hot and during launch. The fixing should ensure mechanical stability and thus accurate positioning in various gravity orientations.In order to ensure reliability during a space flight mission, the optomechanical engineer must understand the requirements of the space flight environment as well as the physics of failure of the optical components themselves; this can minimize the risks of on-orbit failure.This paper focuses on the optomechanical optimal design lens mounting using glue pads bonding. The main idea of this research study is to obtain an optimal choice of the position of the glue to fix the lenses on the barrel in such a way that we obtain a configuration of the optical assembly performance with less stress.In this paper, an investigation was performed using several methods including (thermo-elastic analysis, the margin of safety and lens distortion analysis). The results show that the position with six contacts glue pads is the best configuration compared to other configurations. This solution can be very helpful for decision-makers and optical engineers during the development phases of space optomechanical systems.

Optimum design of a 740 mm-long lens mount for a large-area and high-speed line beam proximity exposure

Proximity exposure with line beam scanning can be an alternative to traditional proximity exposure for a fast, high-resolution, large-area patterning. The optical elements used for shaping the line beams have a very large length-to-cross-sectional area ratio, so even small misalignment has a large effect on the optical path. In this study, a lens mount system based on kinematic coupling was established to accurately locate and align the line beam lens. Finite element models of the line beam lens and the mount were constructed, and then static structural simulations were performed. Optical paths concerning lens deformation and misalignment were calculated based on the vector equations for lines, surfaces, and Snell's law. An optimum design process based on the Taguchi method was carried out to minimize the difference between the actual optical arrival location and the target location. The stiffness and clamping force of the clamp part and support positions were selected as design variables, and the geometrical uncertainties of the lens supports was treated as error factors. A cross product array was constructed for each design variable and error factor, and then a total of 36 simulations were performed. Finally, the influence of each design variable on the optical path was analyzed, and the optimum conditions for the design variables, minimizing the error factor, were determined. As a result, the optical path error due to the geometrical uncertainty was reduced by approximately 30% compared to initial design.

Anterior segment optical coherence tomography angiography

We present a novel method to image the vasculature of the anterior segment of the eye using a non-invasive optical coherence tomography angiography (OCTA) system with a modified lens system. This system utilises the Heidelberg Spectralis OCTA and a 3D printed lens mount holding a simple biconvex lens in place to allow capture of images in the anterior segment.

New solutions in precision lens mounting

Several methods have been developed through the years to mount lenses with the ultimate goal of minimizing their positioning errors with respect to the nominal optical layout. This is a non-trivial task, since it requires either very well controlled manufacturing tolerances or alignment of the optical components into their mounts. This paper reviews the classical lens mounting methods and introduces new solutions to improve the centering accuracy. First, an improved drop-in method called auto-centering is described. This method is based on the use of geometrical relationship between the lens diameter, the lens radius of curvature, and the thread angle of the retaining ring to provide centring error typically less than 0.5 arcmin. In addition, an innovative method that relies on geometric principles to auto-center optomechanical parts to each other is described. The method allows to auto-center an optical group in a main barrel, to perform an axial adjustment of an optical group inside a main barrel, and to perform stacking of multiple barrels within 5 µm of centering error. Finally, to improve the centering accuracy of common method used to center injection molded plastic lenses, a new concept using toroidal interfaces has been developed. This method allows a reduction by at least a factor of two the lens centering error compared to methods based on radial clearance fit for the same manufacturing tolerances.

Development of a modular, high-speed plenoptic-camera for 3D flow-measurement.

This paper describes the development of a Modular Plenoptic Adaptor (MPA) for rapid and reversible conversion of high-speed cameras into plenoptic imaging systems, with the primary goal of enabling single-camera, time-resolved 3D flow-measurements. The MPA consists of a regular imaging lens, a microlens array, a tilt-adjustable microlens mount and an optical relay, which are collectively installed onto a high-speed camera through a standard lens mount. Each component within the system is swappable to optimize for specific imaging applications. In this study, multiple configurations of the MPA were tested and they demonstrated the ability to refocus and shift perspectives within high-speed scenes after capture. Additionally, the MPA demonstrated 3D reconstruction of captured scenes with <1% spatial error across a volume spanning approximately 50×30×50mm3. Finally, the MPA also demonstrated reconstruction of a 3D droplets-field with sufficient quality to support qualitatively accurate plenoptic particle image velocimetry (PPIV) calculations.

机械制冷机冷却的透射式光学系统支撑结构

机械制冷机冷却的透射式光学系统支撑结构

Alignment-free integration of apertures and nontransparent hulls into 3D-printed micro-optics.

The fabrication of 3D-printed micro-optical systems by femtosecond direct laser writing is state of the art. However, the inherent transparency of the lens mount, which is also made of photopolymer, causes a degradation of the image contrast due to stray light and scattering. Furthermore, apertures play a key role in optical design but cannot be directly integrated during 3D printing. Here, we present a superfine inkjet process for targeted filling of 3D-printed cavities in order to integrate apertures and nontransparent hulls without any alignment. Considerable contrast improvement and micro-optical systems with increased functionality are demonstrated.