Lens Module Research Articles

Focus-Switchable Piezoelectric Actuator: A Bionic Thin-Plate Design Inspired by Conch Structure

Traditional camera zoom mechanisms, relying on stepper motors and intricate transmission components, suffer from bulky designs that restrict their applicability in compact systems. This study presents a novel piezoelectric focus-switchable mechanism (PFSM) directly driven by a biomimetic radial-mode piezoelectric actuator (RMPA) with inclined driving structure mimicking the conch shell. The PFSM utilizes rotational motion for optical zoom, providing a more compact and efficient alternative to conventional linear motion-based systems. By utilizing finite element method (FEM) optimization, we developed a compact prototype (34×34×3mm³, 14.83g) and experimentally verified its performance, achieving a peak rotational speed of 1573.14 RPM, torque output of 3.6 mN·m, and step displacement resolution of 45.8 μrad. These attributes enable smooth lens module switching for optical zoom, thus demonstrating the mechanism’s feasibility. Importantly, the PFSM offers precise positioning without relying on additional transmission parts and features a self-locking capability when de-energized, rendering it an ideal choice for camera zoom applications. In summary, this study underscores the PFSM’s potential as a compact, lightweight, and efficient camera zoom mechanism, contributing meaningfully to the field of imaging technology and optical systems.

Design and analysis of the liquid lens system for bionic human eye imaging

In this paper, the liquid lens system for bionic human eye imaging is designed based on the principles of dielectrophoretic drive and hydraulic drive. The core part of this lens system is the biconvex liquid lens of the bionic human eye crystalline lens. Based on this part, a PDMS membrane liquid lens module and a liquid chamber are added, which are combined with the biconvex liquid lens to form a structure that can be used to represent the cornea, the anterior chamber, the vitreous body and other parts of the human eye. It is a combined structural design to realize the whole human eye liquid lens system. The design of the system model and the analysis of ray tracing are mainly accomplished with COMSOL software, and the experimental research of the system is carried out. The whole liquid lens device for the bionic human eye is fabricated; its zoom characteristics and imaging resolution are measured at fixed volumes of liquid injection with different voltages and at fixed voltages with different volumes of liquid injection, respectively. The results show that the zoom range of the liquid lens system for bionic human eye imaging is 24.81mm-13.07 mm, which can reflect the zoom characteristics of general human eyes, and its imaging resolution can reach a maximum of 90.51lp/mm.

Prediction method of long-term creep deformation of mobile phone resin lens module in a harsh temp environment

In recent years, the replacement cycle of digital products such as mobile phones in the market has significantly increased, and the accurate prediction of attenuation under long-term usage conditions of the lens module, storage, and other components has become important. The vast majority of mobile phone lens modules are processed from optical resins, and the degradation of their imaging performance is mainly caused by assembly deformation and long-term creep deformation after a high-temperature reliability test. Therefore, there is an urgent need for a reliable model to describe the long-term creep deformation of the mobile phone resin lens module in a harsh temperature environment. This study proposed a modified derivation method for the parameters of the Maxwell constitutive model to predict the long-term creep deformation of the mobile phone resin lens module in a high-temperature environment. The fitting accuracy of the modified generalized Maxwell model and the time-hardening model were compared through uniaxial compression creep experiments. Long-term creep simulations and experiments were conducted on the mobile phone resin lens module; the deformation law of each component of the mobile phone resin lens module was identified; and the creep deformation mechanism was elucidated. The result shows that the modified generalized Maxwell model has much higher accuracy than the time-hardening model in predicting the long-term creep deformation of different resin materials. When considering the influence of the creep phenomenon, the simulation result matches well with the experimental result, and the high-temperature creep mechanism of the mobile phone resin lens module was clarified. In addition, it was found that the maximum deformation of the lens occurred at the lens with the largest size, which was 2.1 µm, and the position with the largest surface deviation was at the edge of the lens. The prediction method proposed in this study can provide guidance and correction suggestions for the structural design of a mobile phone resin lens module and the rationality of optical design; thus, the imaging accuracy of lens modules will be guaranteed to the greatest extent possible.

Home Automation Using AI Tool

Home automation is becoming increasingly popular as people seek to simplify their lives and improve their living spaces. In this project, we explore how Husky Lens, an AI-powered image recognition sensor, can be used to control home automation systems with the help .of an Arduino board and a relay. By training Husky Lens to recognize different hand gestures or objects, we can use these gestures or objects to control various appliances or devices in our homes. For instance, a user can simply wave their hand in front of the Husky Lens sensor to turn on or off the lights or fan, or use an object such as a Smartphone to activate a door lock or a garage door. The system is built using an Arduino board to communicate with the Husky Lens and relay module, which in turn controls the appliances or devices. This provides a low-cost and customizable solution for home automation that can be easily expanded to incorporate additional features or devices.

Determining Optimal Assembly Condition for Lens Module Production by Combining Genetic Algorithm and C-BLSTM

Mobile camera modules are manufactured by aligning and assembling multiple differently shaped part lenses. Therefore, selecting the part lenses to assemble from candidates (called cavities) and determining the directional angle of each part lens for assembly have been important issues to maximize production yield. Currently, this process is manually conducted by experts at the manufacturing site, and the manual assembly condition optimization carries the risk of reduced production yield and increased failure cost as it largely depends on one’s expertise. Herein, we propose an AI framework that determines the optimal assembly condition including the combination of part lens cavities and the directional angles of part lenses. To achieve this, we combine the genetic algorithm with convolutional bidirectional long-term short-term memory (C-BLSTM). To the best of our knowledge, this is the first study on lens module production finding the optimal combination of part lens cavities and directional angles at the same time using machine learning methods. Based on experimental results using real-world datasets collected by lens module manufacturers, the proposed framework outperformed existing algorithms with an F1 score of 0.89. Moreover, the proposed method (S2S-AE) for predicting the directional angles exhibited the best performance compared to existing algorithms with an accuracy of 78.19%.

Compliant Grasping Control for a Tactile Self-Sensing Soft Gripper.

Soft grippers with good passive compliance can effectively adapt to the shape of a target object and have better safe grasping performance than rigid grippers. However, for soft or fragile objects, passive compliance is insufficient to prevent grippers from crushing the target. Thus, to complete nondestructive grasping tasks, precision force sensing and control are immensely important for soft grippers. In this article, we proposed an online learning self-tuning nonlinearity impedance controller for a tactile self-sensing two-finger soft gripper so that its grasping force can be controlled accurately. For the soft gripper, its grasping force is sensed by a liquid lens-based optical tactile sensing unit that contains a self-sensing fingertip and a liquid lens module and has many advantages of a rapid response time (about 0.04 s), stable output, good sensitivity (>0.4985 V/N), resolution (0.03 N), linearity (R2 > 0.96), and low cost (power consumption: 5 mW, preparation cost <CNY 100). The proposed force controller for the soft gripper was designed based on the Hammerstein nonlinear model, and due to adaptive laws designed by an adaptive theory and the full online sequential extreme learning machine, respectively, its parameters can be adjusted online. The simulation and experiment results demonstrate that the proposed force controller exhibits good force control performance and robustness in a nonlinear contact environment. Moreover, because of its simple control structure and good online learning ability, the proposed controller has the advantages of being real time and easy to realize, which shows its potential applications in many grasping tasks, such as collecting biological samples and sorting industrial products.

Efficient Line Beam Scanning Based on a Hybrid Optical Phased Array Rendering Flexible Field-of-Views

Conventional OPAs incorporating a diffraction grating were mainly developed to achieve a two-dimensional spot beam-based scan, which inevitably requires a wide range of wavelength tuning, leading to unaffordable complexity and limited scanning speed. In this study, we demonstrate a hybrid OPA that capitalizes on a silicon nitride line beam emitter based on tapered waveguides array, which facilitates efficient line beam scanning exhibiting flexible vertical field-of-views (FOVs) at a wavelength of 1550 nm. The line beam is horizontally scanned by driving an array of hybrid-integrated thermo-optic polymer phase modulators. The vertical FOV can be flexibly adjusted by varying the tip widths of the tapers and thus the angular divergence of emitted beams, leading to flexible FOVs ranging from 30° × 14° to 30° × 47°. A lens module is particularly devised and tethered to the OPA, thereby further tailoring and amplifying the FOVs along vertical and horizontal directions. The proposed hybrid OPA in conjunction with a lens module was practically manufactured to efficiently substantiate desired line beam scanning, achieving FOVs ranging from 51° × 0.6° to 51° × 10.3°. The developed line-beam-based OPA is anticipated to play an integral role in embodying an advanced LiDAR system featuring fast beam scanning.

A Novel Methodology for Lens Matching in Compact Lens Module Assembly

Lens matching is a trial assembly step in compact lens module manufacturing that can effectively improve the production yield and compensate for the manufacturing error to some degree. However, conventional lens matching (i.e., through trial and error (T&E)) is extremely time-consuming and has a low success rate. To address this issue, this paper proposes a novel Genetic Algorithm (GA) based solution to improve the assembly success rate and the efficiency of lens matching. The study first formalizes the lens matching problem into an optimization format. Then, a DNN based surrogate model is built to replace expensive optical simulators in the optimization iterations. The DNN is used because it demonstrates a great balance between prediction accuracy and computation efficiency compared to other alternatives, e.g., Linear Regression (LR), Kriging, and Polynomial Chaos Expansion (PCE). Next, a GA-based solver is developed to find optimal lens matching operations. The effectiveness of the proposed method and its superiority over conventional lens matching is validated in the real-world lens production line through collaboration with the industry. Compared with conventional lens matching, the proposed method can significantly improve the production yield and lens matching efficiency. Note to Practitioners—This paper is motivated by a practical need for lens matching in the manufacturing process of the image capturing compact lens modules. The conventional practice of lens matching is tedious, time-consuming, and easy to fail. To address this issue, we mathematically characterize the lens matching problem into an optimization format that can practically be solved by the Genetic Algorithm (GA) or other methods. We then demonstrate the workflow to search for optimal lens matching solutions based on a DNN surrogate model. Simulative studies and preliminary real-world experiments indicate the proposed method can effectively improve overall production yield and is much more efficient than conventional lens matching. The results in mass production further justified the superiority of the proposed method over conventional lens matching.

Design and theoretical analysis of the image-side telecentric zoom system using focus tunable lenses based on Gaussian brackets and lens modules

For now, telecentric system and zoom system have been extensively implemented in machine vision, industrial inspection, etc. However, studies on optical systems with both telecentric and zoom functions are still rare. To improve this situation, we present the design method of the telecentric zoom system with four focus tunable lenses (FTL) and a moving aperture stop (STOP) by applying Gaussian brackets and lens modules. We first improve the Gaussian brackets to achieve the initial parameter solution of the telecentric zoom FTL system, then we introduce a selection method to find the initial structural parameters with sufficient potential for optical design. After that, we use the lens module method to design the initial structure of the optical system, we also expand the combination method of the lens modules which contains an FTL. Finally, the initial structures of a 4X image-side telecentric zoom FTL system are constructed as an example and then optimized using CODEV. As a result, we get an image-side telecentric zoom FTL system with an F/# of 4, a zoom range of 20 mm to 80 mm, an image plane size of 8 mm, and a total length of 218 mm, which performs well in telecentricity control, distortion control, and aberration correction.

Double-sided telecentric zoom optical system using adaptive liquid lenses.

In this paper, the adaptive liquid (AL) lenses are introduced into the double-sided telecentric zoom system, which could greatly decrease the mechanical motion group compared with the traditional zoom system, and only one movable aperture stop (STO) is retained. Firstly, this paper derived the Gaussian brackets used in this system, and we found the appropriate screening method to get the suitable initial structure parameters from the solution space. Then we used the lens module design method to create the initial system. Finally, we used CODEV to further optimize the system, and we got an excellent design result, which controlled the telecentricity of both sides within 0.1°, the distortion was controlled within 0.5%, and the MTF of each zoom configuration above 0.3. This optical system has high application potential and value in the field of precision machine vision. The design method proposed in this article can effectively solve the problem that the zoom system using adaptive liquid lenses lacks the initial structure.

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.

Core characteristics and technology development status of optical glass materials for camera lenses

For core imaging technologies, various R&amp;D for optical lens design have been carried out to realize highresolution images without distortion. The need for systematic analysis of the optical and physical properties of various materials and the correlation for optical lens design has increased. Therefore, core characteristics of visible optical glass material such as refractive index, dispersion value, transmittance, coefficient of thermal expansion, and striae were reviewed from the viewpoint of improving the performance of optical lenses. In this study, the correlation between the refractive index and dispersion value of the optical glass material and the performance of optical lens module is explained by minimizing the chromatic aberration of various wavelength. In addition, we reviewed the refractive index distribution of global leading group's optical glass, which is the most widely used in optical lens manufacturing, and the current status of optical glass technology development at KOPTI.

Use of Six Plastic Lenses to Design Lens Module with 13 Million Pixels for Application in Cellphone Camera Module

Use of Six Plastic Lenses to Design Lens Module with 13 Million Pixels for Application in Cellphone Camera Module

Characterization of Cubic Zirconia as a Lens Material Suitable for Autonomous Driving

As the development of autonomous driving technology is now in full swing, the demand for miniaturized optical modules mounted on various sensors has increased. Particularly, the optical lens used for such autonomous driving must demonstrate stable performance and durability despite rapid changes in the external environment. In this regard, cubic zirconia (CZ) can be used as an optical lens due to its high refractive index, which is above 2.1 in visible and near-infrared wavelengths, along with its chemical and mechanical durability. Thus, in this paper, we investigated the temperature-dependent physical properties of CZ fabricated by the skull melting method. The temperature coefficient of the refractive index (dn/dT) of the fabricated CZ plate in the temperature range of 25–100 °C decreased from 9.76 × 10−5/K to 7.00 × 10−5/K as the wavelength increased from 447.0 nm to 785.0 nm. The estimated Abbe number decreased from 33.98 at 25 °C to 33.12 at 100 °C, while the measured coefficient of thermal expansion (CTE) was 9.91 × 10−6/K, which revealed that the dn/dT value of the CZ plate was more affected by the dispersion than by the CTE. In addition, the CZ samples with a high refractive index, coated with a dielectric multilayer showed a high average transmittance of 98.2% at the investigated wavelengths, making it suitable for miniaturization or wide-angle optical lens modules. To secure the durability required for automobile lenses, the variation in the surface profile of the CZ before and after the external impact was also analyzed, revealing much better performance than TAF glass. Therefore, the observed results demonstrate that the CZ material is suitable for use as an optical lens for autonomous vehicles.

Performance improvements of IFM Nano Thruster with highly focused ion beam generated with a compact electrostatic lens module

The requirements for electric propulsion systems suitable for scientific missions are becoming increasingly stringent. This includes, in particular, the reduction of the beam divergence and the alignment accuracy of the thrust vector. Therefore, a modular electrostatic lens module has been developed by using an ion trajectory simulation model which considers the ion produced space charge. The focus module can be mounted on an IFM Nano Thruster with equal side length of 100mm and it works for the entire operation envelope without increasing the electronics complexity. Experimental beam diagnostics measurements and performance analyses are carried out on an IFM Nano Thruster laboratory model with and without attached focus module. The results show an improvement in thrust and specific impulse of up to 30%. In addition, the beam divergence half-angle is drastically reduced down to <20∘ half-angle and a high thrust vector accuracy of <0.9∘ is achieved. In addition, the focus module significantly reduces the droplet contamination angle. With this design evolution, the IFM Nano Thruster is becoming a suitable candidate for highly complex scientific missions, such as NGGM.

Grinding edge machining process on small-sized lens module components in a mobile phone.

The periscope phone lens has a bright application prospect; however, the problem of a large chipping size in the grinding process for the periscope phone lens module components seriously limits its development. We address the problem of the large edge chipping size in the grinding process of small-sized module components of periscope mobile phone cameras by investigating the influence of the grinding speed, feed speed, and grinding depth on the chipping size through theoretical simulation analysis and single-factor variable experimental verification. The optimal grinding process parameters were preferred, and yield experiments were conducted using the preferred process parameters. The results show that increasing the grinding speed and decreasing the feed speed and grinding depth can effectively suppress the chipping size of the component grinding edge.

Surrogate neural network model for sensitivity analysis and uncertainty quantification of the mechanical behavior in the optical lens-barrel assembly

Surrogate neural network-based models have been lately trained and used in a variety of science and engineering applications where the number of evaluations of a target function is limited by execution time. In cell phone camera systems, various errors, such as interferences at the lens-barrel and lens-lens interfaces and axial, radial, and tilt misalignments, accumulate and alter profile of the lenses in a stochastic manner which ultimately changes optical focusing properties. Nonlinear finite element analysis of the stochastic mechanical behavior of lenses due to the interference fits is used on high-performance computing (HPC) to generate sufficient training and testing data for subsequent deep learning. Once properly trained and validated, the surrogate neural network model enabled accurate and almost instant evaluations of millions of function evaluations providing the final lens profiles. This computational model, enhanced by artificial intelligence, enabled us to efficiently perform Monte-Carlo analysis for sensitivity and uncertainty quantification of the final lens profile to various interferences. It can be further coupled with an optical analysis to perform ray tracing and analyze the focal properties of the lens module. Moreover, it can provide a valuable tool for optimizing tolerance design and intelligent components matching for many similar press-fit assembly processes.

A Stray Light Detection Model for VR Head-Mounted Display Based on Visual Perception

In recent years, the general public and the technology industry have favored stereoscopic vision, immersive experience, and real-time visual information reception of virtual reality (VR) and augmented reality (AR). The device carrier, the Head-Mounted Display (HMD), is recognized as one of the next generation’s most promising computing and communication platforms. HMD is a virtual image optical display device that combines optical lens modules and binocular displays. The visual impact it brings is much more complicated than the traditional display and also influences the performance of image quality. This research investigated the visual threshold of stray light for three kinds of VR HMD devices, and proposes a qualitative model, derived from psychophysical experiments and the measurement of images on VR devices. The recorded threshold data of the psychophysical stray light perception experiment was used as the target when training. VR display image captured by a wide-angle camera was processed, through a series of image processing procedures, to extract variables in the range of interest. The machine learning algorithm established an evaluation method for human eye-perceived stray light in the study. Four supervised learning algorithms, including K-Nearest Neighbor (KNN), Logistic Regression (LR), Support Vector Machine (SVM), and Random Forest (RF), were compared. The established model’s accuracy was about 90% in all four algorithms. It also proved that different percentages of thresholds could be used to label data according to demand to predict the feasibility of various subdivision inspection specifications in the future. This research aimed to provide a fast and effective stray light qualitative evaluation method to be used as a basis for future HMD optical system design and quality control. Thus, stray light evaluation will become one of the critical indicators of image quality and will be applicable to VR or AR content design.

24‐4: Student Paper: High Precision Beam Angle Expander Based on Polymeric Liquid Crystal Polarization Lenses for LiDAR Applications

A novel beam steering angle expander is demonstrated by cascading two polymeric liquid crystal polarization lenses with different diopters. The lens module performs as a planar telescope, which is featured as lightweight, low cost, and high precision. The magnifier offers wide‐angle continuous steering when integrated with an active fine‐angle beam steerer.

Lens design for parallel cylindrical anamorphic attachments with finite object distance.

A lens design method for parallel cylindrical anamorphic attachments with finite object distance is provided, which includes paraxial lens design, thin lens design, and thick lens design. The paraxial lens data can be determined from geometric optics. The thin lens design adopts a total of 28 anamorphic aberrations. The anamorphic lens splitting method for each anamorphic lens module is also provided for anamorphic aberration balancing between anamorphic lens modules. With the proposed design method, an anamorphic attachment is designed and manufactured in this paper, which proves the feasibility of the method.