Adjoint-Assisted Shape Optimization of Microlenses for CMOS Image Sensors

Recently, there have been significant developments in the designs of CMOS image sensors to achieve high-resolution sensing capabilities. One of the fundamental factors determining the sensor’s ability to capture high-resolution images is its efficiency in focusing the visible light onto the photosen...

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Main Authors: Rishad Arfin, Jens Niegemann, Dylan McGuire, Mohamed H. Bakr
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/24/23/7693
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author Rishad Arfin
Jens Niegemann
Dylan McGuire
Mohamed H. Bakr
author_facet Rishad Arfin
Jens Niegemann
Dylan McGuire
Mohamed H. Bakr
author_sort Rishad Arfin
collection DOAJ
description Recently, there have been significant developments in the designs of CMOS image sensors to achieve high-resolution sensing capabilities. One of the fundamental factors determining the sensor’s ability to capture high-resolution images is its efficiency in focusing the visible light onto the photosensitive region of the submicron scale. In most CMOS imaging technologies, this is typically achieved through microlenses. Light collection under diverse conditions can be significantly improved through the efficient design of microlenses. While the optimization of microlenses appears to be imperative, achieving efficient designs of microlenses for high-density pixels under various conditions remains a significant challenge. Therefore, a systematic optimization approach is required to accelerate the development of efficient microlenses with enhanced optical performance. In this paper, we present an approach to optimize the shape of CMOS microlenses through adjoint sensitivity analysis (ASA). A novel figure of merit (FOM) is developed and incorporated into the optimization process to enhance the light collection. The gradient of the FOM is computed iteratively using two field simulations only. The functionality and robustness of the optimization framework are thoroughly evaluated. Furthermore, the performance of the optimized CMOS microlenses is compared to that of the conventional microlenses. The adjoint-assisted optimization framework presented here can be further used to develop efficient optical devices that perform optical manipulation such as concentrating, bending, or dispersing light in compact imaging systems.
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spelling doaj-art-5c749d1d8c724989b634e77dfd9b26372025-08-20T02:50:37ZengMDPI AGSensors1424-82202024-11-012423769310.3390/s24237693Adjoint-Assisted Shape Optimization of Microlenses for CMOS Image SensorsRishad Arfin0Jens Niegemann1Dylan McGuire2Mohamed H. Bakr3Department of Electrical & Computer Engineering, McMaster University, Hamilton, ON L8S 4K1, CanadaAnsys Canada Ltd., 1700-1095 West Pender Street, Vancouver, BC V6E 2M6, CanadaAnsys Canada Ltd., 1700-1095 West Pender Street, Vancouver, BC V6E 2M6, CanadaDepartment of Electrical & Computer Engineering, McMaster University, Hamilton, ON L8S 4K1, CanadaRecently, there have been significant developments in the designs of CMOS image sensors to achieve high-resolution sensing capabilities. One of the fundamental factors determining the sensor’s ability to capture high-resolution images is its efficiency in focusing the visible light onto the photosensitive region of the submicron scale. In most CMOS imaging technologies, this is typically achieved through microlenses. Light collection under diverse conditions can be significantly improved through the efficient design of microlenses. While the optimization of microlenses appears to be imperative, achieving efficient designs of microlenses for high-density pixels under various conditions remains a significant challenge. Therefore, a systematic optimization approach is required to accelerate the development of efficient microlenses with enhanced optical performance. In this paper, we present an approach to optimize the shape of CMOS microlenses through adjoint sensitivity analysis (ASA). A novel figure of merit (FOM) is developed and incorporated into the optimization process to enhance the light collection. The gradient of the FOM is computed iteratively using two field simulations only. The functionality and robustness of the optimization framework are thoroughly evaluated. Furthermore, the performance of the optimized CMOS microlenses is compared to that of the conventional microlenses. The adjoint-assisted optimization framework presented here can be further used to develop efficient optical devices that perform optical manipulation such as concentrating, bending, or dispersing light in compact imaging systems.https://www.mdpi.com/1424-8220/24/23/7693adjoint sensitivity analysis (ASA)optimizationmicrolensesCMOS image sensor
spellingShingle Rishad Arfin
Jens Niegemann
Dylan McGuire
Mohamed H. Bakr
Adjoint-Assisted Shape Optimization of Microlenses for CMOS Image Sensors
Sensors
adjoint sensitivity analysis (ASA)
optimization
microlenses
CMOS image sensor
title Adjoint-Assisted Shape Optimization of Microlenses for CMOS Image Sensors
title_full Adjoint-Assisted Shape Optimization of Microlenses for CMOS Image Sensors
title_fullStr Adjoint-Assisted Shape Optimization of Microlenses for CMOS Image Sensors
title_full_unstemmed Adjoint-Assisted Shape Optimization of Microlenses for CMOS Image Sensors
title_short Adjoint-Assisted Shape Optimization of Microlenses for CMOS Image Sensors
title_sort adjoint assisted shape optimization of microlenses for cmos image sensors
topic adjoint sensitivity analysis (ASA)
optimization
microlenses
CMOS image sensor
url https://www.mdpi.com/1424-8220/24/23/7693
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AT jensniegemann adjointassistedshapeoptimizationofmicrolensesforcmosimagesensors
AT dylanmcguire adjointassistedshapeoptimizationofmicrolensesforcmosimagesensors
AT mohamedhbakr adjointassistedshapeoptimizationofmicrolensesforcmosimagesensors