Light Sensing Module Structure for Blocking External Light Crosstalk
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Solution Overview
Problem
Conventional wearable devices face challenges in accurately monitoring physiological signals due to interference from skin color, environmental brightness, improper device fit, and limited light sensor size, which affects the interpretation of weak signals and can lead to inaccurate exercise intensity feedback.
Innovation Solution
A light sensing module with a substrate, light sensing unit, first light-transmissive component, and blocking wall, where the first light-transmissive component covers the light sensing unit and has a refractive index between that of the light sensing unit and air, and a blocking wall surrounds the unit with low light transmittance, enhancing sensitivity and accuracy by reducing external light crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional light sensor is used in wearable devices, then the device can monitor physiological signals, but the monitoring accuracy is degraded by external light interference and limited sensor size
Solution Approach 1:
The patent introduces a light guide plate as an intermediary component between the light sensor and external environment. This light guide plate redirects external light away from the sensor while allowing the sensor to detect physiological signals through the finger, thereby mediating the interaction between the sensor and harmful external light
Solution Approach 2:
The patent applies different structural qualities to different regions: the light guide plate has specific optical properties to redirect light, the sensor region is optimized for detecting physiological signals, and the overall structure is designed to create local optical environments that favor signal detection while blocking interference
2Area of moving object
If the light sensor size is increased to improve sensing range, then more physiological signals can be detected, but the wearable device becomes larger and less portable
Solution Approach 1:
The patent utilizes the third dimension by implementing a light guide plate structure that redirects light from lateral directions. This allows the sensor to effectively capture light from a larger spatial volume without increasing the planar footprint of the sensor itself, thereby expanding the functional light receiving area in a dimensional sense
3Weight of moving object
If the wearable device is designed to be compact and lightweight, then portability is improved, but the light sensor area is limited reducing monitoring sensitivity
Solution Approach 1:
The light guide plate structure enables the sensor to capture light from three-dimensional space around the finger, effectively increasing the light gathering capability without increasing the sensor's physical size or the device's weight
4Object-affected harmful factors
If a blocking wall is added to reduce external light interference, then light crosstalk is reduced, but the device structure becomes more complex
Solution Approach 1:
The light guide plate serves multiple functions simultaneously: it guides the working light to the sensor, redirects external light away from the sensor, and structurally supports the sensor in position. By combining multiple functions in a single component, the overall structural complexity is minimized while achieving effective light interference reduction
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 solution expands the sensing range, reduces blind spots, and improves the accuracy of physiological signal monitoring by minimizing external light interference, enabling more reliable exercise performance feedback.
Implementation Method 1
The first light-transmissive component covers the light sensing unit, and has a first refractive index that is between a refractive index of the light sensing unit and a refractive index of air
Implementation Method 2
The blocking wall is disposed on the substrate, and surrounds the light sensing unit and the first light-transmissive component
Data Source
AI summary
A light sensing module and an electronic device using the same are provided. The light sensing module includes a substrate, a light sensing unit, a first light-transmissive component and a blocking wall. The light sensing unit is disposed on the substrate to sense an intensity of a working light beam. The first light-transmissive component covers the light sensing unit, and has a first refractive index that is between a refractive index of the light sensing unit and a refractive index of air. The blocking wall is disposed on the substrate, and surrounds the light sensing unit and the first light-transmissive component.