• Title/Summary/Keyword: structure-sensitivity

Search Result 1,598, Processing Time 0.027 seconds

High-sensitivity NIR Sensing with Stacked Photodiode Architecture

  • Hyunjoon Sung;Yunkyung Kim
    • Current Optics and Photonics
    • /
    • v.7 no.2
    • /
    • pp.200-206
    • /
    • 2023
  • Near-infrared (NIR) sensing technology using CMOS image sensors is used in many applications, including automobiles, biological inspection, surveillance, and mobile devices. An intuitive way to improve NIR sensitivity is to thicken the light absorption layer (silicon). However, thickened silicon lacks NIR sensitivity and has other disadvantages, such as diminished optical performance (e.g. crosstalk) and difficulty in processing. In this paper, a pixel structure for NIR sensing using a stacked CMOS image sensor is introduced. There are two photodetection layers, a conventional layer and a bottom photodiode, in the stacked CMOS image sensor. The bottom photodiode is used as the NIR absorption layer. Therefore, the suggested pixel structure does not change the thickness of the conventional photodiode. To verify the suggested pixel structure, sensitivity was simulated using an optical simulator. As a result, the sensitivity was improved by a maximum of 130% and 160% at wavelengths of 850 nm and 940 nm, respectively, with a pixel size of 1.2 ㎛. Therefore, the proposed pixel structure is useful for NIR sensing without thickening the silicon.

Design Sensitivity Analysis for the Vibration Characteristic of Vehicle Structure (수송체 구조물의 진동특성에 관한 설계민감도 해석)

  • 이재환
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 1992.10a
    • /
    • pp.19-24
    • /
    • 1992
  • Design sensitivity analysis method for the vibration of vehicle structure is developed using adjoint variable method. A variational approach with complex response method is used to derive sensitivity expression. To evaluate sensitivity, FEM analysis of ship deck and vehicle structure are performed using MSC/NASTRAN on the super computer CRAY2S, and sensitivity computation is carried on PC. The accuracy of sensitivity is verified by the results of finite difference method. When compared to structural analysis time on CRAY2S, sensitivity computation is remarkably economical. The sensitivity of vehicle frame can be used to reduce the vibration responses such as displacement and acceleration of vehicle.

  • PDF

The Diaphragm Structure Using the Local Surface Etching for the Improvement of Sensitivity Characteristics (감도특성 향상을 위한 국부적 표면식각 다이아프램 구조 연구)

  • Lee, Gon-Jae;Oh, Dong-Hwan;Lee, Jong-Hong;Kim, Sung-Jin
    • Journal of Sensor Science and Technology
    • /
    • v.13 no.4
    • /
    • pp.309-315
    • /
    • 2004
  • In the pressure sensor, about below 20 kPa, the center boss diaphragm structure is generally used, but it is hard to obtain the high sensitivity because the center boss structure is limited at the thickness and size of diaphragm with chip size. Therefore, this paper suggests that the Center boss structure has surface etched diaphragm using a stress concentration to improve the sensitivity. We carried out the simulation and fabrication applied new diaphragm design. In the result, the sensitivity is improved to 60% without the change of non-linearity (0.14%FS). So, the Center boss of surface etched diaphragm can be applied for the high sensitivity in the low-pressure sensor.

Flexible Pressure Sensors Based on Three-dimensional Structure for High Sensitivity

  • Jung, Young;Cho, Hanchul
    • Journal of Sensor Science and Technology
    • /
    • v.31 no.3
    • /
    • pp.145-150
    • /
    • 2022
  • The importance of flexible polymer-based pressure sensors is growing in fields like healthcare monitoring, tactile recognition, gesture recognition, human-machine interface, and robot skin. In particular, health monitoring and tactile devices require high sensor sensitivity. Researchers have worked on sensor material and structure to achieve high sensitivity. A simple and effective method has been to employ three-dimensional pressure sensors. Three-dimensional (3D) structures dramatically increase sensor sensitivity by achieving larger local deformations for the same pressure. In this paper, the performance, manufacturing method, material, and structure of high-sensitivity flexible pressure sensors based on 3D structures, are reviewed.

Crack Detection in Beam using Sensitivity Coefficient of Modal Data (모달 데이터의 감도계수를 이용하여 보의 균열 탐지)

  • Lee, Jung Youn
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.22 no.6
    • /
    • pp.950-956
    • /
    • 2013
  • This paper describes a sensitivity-coefficient-based iterative method for detecting cracks in a structure. The sensitivity coefficients of a cracked structure are obtained by changing its eigenvectors. The proposed method is applied to a cracked cantilever. The crack is modeled as a rotational stiffness. The predicted cracks are in good agreement with those from a structural reanalysis of the cracked structure.

Effects of the Component Structures on the Vibration of the Total system Using Design Sensitivity Analysis (설계 민감도를 이용한 부분 구조물의 기여도 분석)

  • Lee, Sun-Byung;Yim, Hong-Jae;Kim, Hyo-Sik
    • Proceedings of the KSME Conference
    • /
    • 2001.06b
    • /
    • pp.533-539
    • /
    • 2001
  • In this research, design Sensitivity Analysis is presented for commercial vehicle such as large scale structural system. The proposed method is based on vibration analysis of the total structure and design sensitivity to identify the contribution factor of the component structure to the total system structure. In addition, approximated equations derived from response surface method are used for representative section properties of the thin walled beams.

  • PDF

Sensitivity analysis for optimal design of piezoelectric structures (압전지능구조물의 최적설계를 위한 민감도 해석)

  • 김재환
    • Journal of KSNVE
    • /
    • v.8 no.2
    • /
    • pp.267-273
    • /
    • 1998
  • This study aims at performing sensitivity analysis of piezoelectric smart structure for minimizing radiated noise from the structure, The structure consists of a flat plate on which disk shaped piezoelectric actuator is mounted, and finite element modeling is used for the structure. The finite element modeling uses a combination of three dimensional piezoelectric, flat shell and transition elements so thus it can take into account the coupling effects of the piezoelectric device precisely and it can also reduce the degrees of freedom of the finite element model. Electric potential on the piezoelectric actuator is taken as a design variable and total radiated power of the structure is chosen as an objective function. The objective function can be represented as Rayleigh's integral equation and is a function of normal displacements of the structure. For the convenience of computation, all degrees of freedom of the finite element equation is condensed out except the normal displacements of the structure. To perform the design sensitivity analysis, the derivative of the objective function with respect to the normal displacements is found, and the derivative of the norma displacements with respect to the design variable is calculated from the finite element equation by using so called the adjoint variable method. The analysis results are compared with those of the finite difference method, and shows a good agreement. This sensitivity analysis is faster and more accurate than the finite difference method. Once the sensitivity analysis program is used for gradient-based optimizations, one could achieve a better convergence rate than non-derivative methods for optimal design of piezoelectric smart structures.

  • PDF

Vibration Analysis of Bus Structure using Sensitivity Analysis of Bus Component Structures (부분 구조물의 민감도 분석을 이용한 버스차체의 진동분석)

  • Lee, Sang-Beom
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.18 no.4
    • /
    • pp.355-361
    • /
    • 2009
  • In this paper, an analysis technique is presented for performing the effective design of bus structure. Sensitivity analysis is carried out for the natural frequency of component structures consisting of bus B.I.W. Local vibration modes of substructure, which large affect on the global vibration mode of the bus B.I.W., are obtained through the sensitivity analysis technique using the mathematical chain rule. And also the design variables, which are determined from the sensitivity analysis, are redesigned through optimum design process. The proposed analysis technique shows that the bus structure can be effectively designed considering the vibration characteristics.

  • PDF

Design Sensitivity Analysis of Elasto-perfectly-plastic Structure for Stiffened Shell Structure (탄성-완전-소성 보강쉘 구조물의 설계민감도해석)

  • Jung, Jae-Joon;Lee, Tae-Hee;Lim, Jang-Keun
    • Proceedings of the KSME Conference
    • /
    • 2001.11a
    • /
    • pp.746-752
    • /
    • 2001
  • Design sensitivity analysis for nonlinear structural problems has been emerged in the last decade as a glowing area of engineering research. As a result, theoretical formulations and computational algorithms have already developed for design sensitivity of nonlinear structural problems. There is not enough research for practical nonlinear problems using multi-element, due to difficulties of implementation into FEA. Therefore, nonlinear response analysis for stiffened shell which consists of Mindlin plate and Timoshenko beam, was considered. Specially, it presents the backward-Euler method which is adopted to describe an exact yield state in the stress computation procedure. Then, design sensitivity analysis of nonlinear structures, particularly elasto-perfectly-plastic structure, is developed using direct differentiation method. The accuracy of the developed sensitivity analysis was compared with the central finite difference method. Finally, on the basis of above results, design improvement for stiffened shell is suggested.

  • PDF

Modal Parameter Sensitivity Analysis Using Component Mode Synthesis Method (부분 구조물의 모드 합성을 이용한 구조물 모드 매개변수의 민감도 해석)

  • 김형중;박윤식
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 1997.04a
    • /
    • pp.184-191
    • /
    • 1997
  • A method, termed as the substructural sensitivity synthesis method, which utilizes the computational merits of the component mode synthesis technique is proposed to calculate design sensitivity of modal parameters of substructurally combined structures. In this method, the sensitivity analysis is combined with component mode synthesis thchnique. thus the degrees of freedom of a combined structure can be dramatically reduced. Free-interface mode method including the residual attachment modes among the component mode synthesis methods is used to calculate the modal sensitivity of the combined structure. For the design sensitivities of modal properties of structure, the Nelson's method, which is exact solving method is used. It is shown that the modal sensitivities of the entire structure can be obtained by synthesizing the substructural modal data, and the sensitivities of the modal data about the design variables of modifiable substructure. Using the proposed method, the final degrees of freedom of entire structure can be remarkably reduced to calculate the modal parameter sensitivities. With a structure composed of beams and plates, as an example, the sensitivities of the eigenvalues and eigenvectors obtained by this proposed method were compared with the exact solutions in terms of accuracy.

  • PDF