Optical Sensor Electrode Structure for Linear I-V Response
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Solution Overview
Problem
Current optical sensors for detecting optical radiation, especially in the infrared spectral range, face challenges in providing a simple, cost-efficient, and reliable solution for sensing transmissivity, absorption, emission, and reflectance, while also accurately determining the position of objects in terms of depth and width, with deviations from Ohm's law in their current-voltage characteristics.
Innovation Solution
An optical sensor design featuring a photoconductive layer with a specific electrode-photoconductor interface structure, comprising segments with varying thicknesses, and an electrically conducting laminate with a charge carrier, bonding, and barrier layers, to achieve a linear current-voltage characteristic symmetric with respect to voltage and current, thereby minimizing deviations from Ohm's law.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional optical sensor with photoconductive material is used, then the sensor can detect optical radiation, but the current-voltage characteristic deviates from Ohm's law due to the resistive behavior of the photoresistor
Solution Approach 1:
The electrode layer is divided into multiple segments with different thicknesses (first segment with thickness d1, second segment with thickness d2, third segment with thickness d3). This segmentation allows different portions of the electrode to provide different electrical characteristics, collectively achieving a linear current-voltage relationship that compensates for the non-linear resistive behavior of the photoconductive material.
Solution Approach 2:
Different segments of the electrode layer are assigned different thicknesses to create local variations in electrical properties. The first segment has uniform thickness d0, the second segment has increased thickness (equal to or exceeding d0), and the third segment has continuously decreasing thickness. This local quality variation enables precise control over the electrical characteristics to achieve overall linearity.
2Reliability
If the electrode layer has uniform thickness, then the manufacturing is simple, but the current-voltage characteristic cannot be made linear to satisfy Ohm's law
Solution Approach 1:
The electrode layer is segmented into three distinct regions with different thickness profiles. The first segment maintains uniform thickness for ease of manufacturing, while the second and third segments introduce controlled thickness variations. This segmentation strategy balances manufacturing feasibility with the requirement for linear electrical characteristics.
Solution Approach 2:
Instead of varying electrode properties in the planar dimension, the invention introduces thickness variation in the vertical dimension. This dimensional approach allows control over electrical characteristics without fundamentally changing the planar layout, maintaining compatibility with standard manufacturing processes while achieving the desired electrical linearity.
3Adaptability or versatility
If photoconductive material is used for detection, then the sensor can operate in infrared spectral range, but the resistive behavior causes non-linear current-voltage characteristics
Solution Approach 1:
The multi-segmented electrode layer acts as an intermediary between the photoconductive material and the external circuit. It transforms the non-linear resistive behavior of the photoconductive material into a linear current-voltage relationship, allowing the sensor to maintain its infrared detection capability while achieving compliant electrical characteristics for reliable operation.
Solution Approach 2:
The sensor structure combines photoconductive material with a composite electrode layer having spatially varying thickness. This composite structure integrates the infrared detection capability of the photoconductive material with the linearizing electrical characteristics of the segmented electrode, achieving both detection versatility and electrical reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The sensor exhibits a linear current-voltage characteristic according to Ohm's law, enhancing its reliability and efficiency in detecting optical radiation and determining object positions with improved accuracy and cost-effectiveness.
Implementation Method 1
the optical sensor comprises a photoconductive layer having at least one photoconductive material
Data Source
AI summary
Described herein is an optical sensor, a detector including the optical sensor for an optical detection of at least one object, and a method for manufacturing the optical sensor. The optical sensor (110) includesa substrate (120);a photoconductive layer (112) applied to a first portion (116) of a surface (118) of the substrate (120); andat least one electrode layer (124) applied to a second portion (126) of the surface (118) of the substrate (120).The optical sensor (110) exhibits a linear current-voltage characteristic according to Ohm's law.