Semiconductor Optical Sensor Crosstalk Reduction via Shielding
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Solution Overview
Problem
The performance of optical sensor systems is degraded by unabsorbed incident optical signals causing crosstalk among photo sensitive elements, leading to inaccurate measurement results.
Innovation Solution
A semiconductor optical sensor design incorporating a substrate, optical sensing elements made of different materials, lenses matching the substrate material for focused signal guidance, optical confinement elements to absorb or reflect unabsorbed signals, and optical reflection elements to enhance optical-electrical conversion efficiency, preventing signal leakage between adjacent sensing units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical sensor system uses a simple structure without additional optical elements, then the device complexity is low, but optical crosstalk occurs between adjacent sensing units degrading measurement precision
Solution Approach 1:
The optical sensor array is divided into independent sensing units, each surrounded by its own optical shielding element. This segmentation prevents optical signals from one sensing unit from interfering with adjacent units, thereby eliminating crosstalk while maintaining modular structure
Solution Approach 2:
An optical shielding element is introduced as an intermediary component between the lens and the sensing units. This shielding element absorbs or reflects stray optical signals before they can reach adjacent sensing units, preventing crosstalk without significantly complicating the overall structure
2Use of energy by moving object
If the optical sensor uses larger photo sensitive elements to capture more light, then the light gathering capability is improved, but the unabsorbed optical signal propagates further causing increased crosstalk
Solution Approach 1:
The optical shielding element converts harmful stray optical signals into beneficial absorbed or reflected energy. By positioning the shielding element to intercept unabsorbed optical signals, the system prevents these signals from causing crosstalk while the shielding material itself handles the energy safely
Solution Approach 2:
The optical shielding element is strategically positioned only in regions where stray light propagation is problematic, specifically around the periphery of each sensing unit. This localized approach addresses crosstalk issues without adding shielding throughout the entire optical path, optimizing both performance and structure
3Measurement precision
If the optical sensor system adds optical shielding elements to prevent crosstalk, then measurement precision is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The optical shielding element is merged with the substrate structure, forming an integrated component rather than a separate add-on. This integration allows the shielding function to be achieved through standard semiconductor fabrication processes, simplifying manufacturing while maintaining crosstalk prevention
Solution Approach 2:
The optical shielding element serves multiple functions: it blocks stray light to prevent crosstalk, provides structural support for the sensing unit, and can be fabricated using the same material and processes as the substrate. This multi-functionality reduces the need for additional components and simplifies manufacturing
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
This design effectively reduces optical crosstalk and dark current by confining and reflecting unabsorbed optical signals, thereby improving measurement accuracy and signal conversion efficiency.
Implementation Method 1
a lens using a same material with that of the substrate and changing a propagation path of the incident optical signal to guide the incident optical signal to the optical sensing element
Implementation Method 2
an optical sensing element using a different material with that of the substrate and converting the incident optical signal into the electric signal
Implementation Method 3
an optical shielding element surrounding the optical sensing element and changing the propagation path of the incident optical signal or a propagation distance of the incident optical signal such that the incident optical signal does not further propagate to another sensing unit
Implementation Method 4
an optical reflection element arranged atop the optical sensing element and reflecting an unabsorbed component of the incident optical signal
Data Source
AI summary
A semiconductor optical sensor includes a plurality of sensing units and to senses an incident optical signal to generate an electrical signal. One of the sensing units includes a substrate, an optical sensing element, a lens and an optical shielding element. The optical sensing element, whose material is different from that of the substrate, converts the incident optical signal into the electrical signal. The lens, whose material includes the same as that of the substrate, guides the incident optical signal to the optical sensing element by changing the propagation path of the incident optical signal. The optical shielding element, which surrounds the optical sensing element, alters the propagation path or propagation distance of the incident optical signal after the incident optical signal passes through the lens such that the incident optical signal will not reach an optical sensing element of an adjacent sensing unit.