Miniaturized PPG Sensor with Inter-Chip Shielding
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Solution Overview
Problem
Conventional photo-plethysmography sensors used in wearable devices are difficult to miniaturize, limiting their application range due to size constraints.
Innovation Solution
A sensing device design featuring a substrate with an emitting chip, a receiving chip, and a shielding structure that covers the wire and a portion of the chip connected to it, allowing for a reduced size configuration by positioning the shielding structure between the chips and covering the wire, thereby minimizing the device's overall dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional photo-plethysmography sensor is used in a wearable device, then the sensor can measure heart rate or blood oxygen, but the sensor size is difficult to be reduced which limits the range of application
Solution Approach 1:
The sensor is divided into two separate chips: an emitting chip and a receiving chip. These chips are positioned at intervals on a substrate, allowing the overall sensor structure to be miniaturized while maintaining functional performance. The segmentation enables flexible arrangement and reduces the volume required for each individual component.
Solution Approach 2:
The wire connecting the emitting chip to the substrate is routed through the space between the two chips, utilizing the vertical dimension and inter-chip spacing rather than requiring additional lateral space. This three-dimensional wire routing approach minimizes the overall footprint of the sensor device.
2Measurement precision
If the wire is connected between the two chips, then electrical connection is achieved, but the wire may be exposed to light interference affecting measurement precision
Solution Approach 1:
A shielding structure is introduced as an intermediary element between the emitting chip and receiving chip. This shielding structure covers the wire connection and blocks light from reaching the wire, preventing light interference while maintaining electrical connectivity. The shield acts as a mediator that protects the sensitive wire from environmental light without complicating the overall device architecture.
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 proposed design effectively reduces the size of the sensing device by 35% compared to conventional devices, enabling more versatile applications in wearable technology.
Implementation Method 1
an emitting chip (20), the emitting chip (20) is capable of emitting a sensing light beam
Implementation Method 2
a receiving chip (30), the receiving chip (30) is capable of receiving the sensing light beam
Implementation Method 3
The shielding structure is located between the two chips, and the shielding structure covers the wire and a portion of the chip connected to the wire
Data Source
AI summary
A sensing device includes a substrate, two chips, and a shielding structure. The two chips are respectively defined as an emitting chip and a receiving chip. The emitting chip can emit a sensing light beam, the receiving chip can receive the sensing light beam, and the two chips are fixed in position on the substrate at intervals. At least one of the chips is electrically connected to the substrate through at least one wire, and a position where the wire is connected to the substrate is located between the two chips. The shielding structure is formed on the substrate. The shielding structure is located between the two chips, and the shielding structure covers the wire and a portion of the chip connected to the wire. Compared with the conventional photo-plethysmography sensor, the sensing device has the advantage of a smaller size.