Pulse Wave Sensor Light Guide for Stable Skin Contact
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Solution Overview
Problem
Photoelectric pulse wave sensors face challenges in maintaining stable and high-sensitivity pulse wave detection when mounted on wearable devices due to difficulties in achieving and maintaining tight contact with the skin, especially with body motion, leading to increased noise and reduced signal-to-noise ratio.
Innovation Solution
A pulse wave detection device with a sensor substrate and a light guide part that includes openings and reflective surfaces to guide light to and from light emitting and receiving elements, using an elastic material to ensure tight contact with the skin and minimize noise, even with body motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a photoelectric pulse wave sensor is mounted on a wearable device, then portability and wearability are improved, but contact stability with the skin deteriorates due to body motion
Solution Approach 1:
The patent employs a flexible membrane structure that conformally contacts the skin surface, allowing the sensor to adapt to body contours and maintain stable contact during motion. The membrane acts as a flexible interface between the rigid sensor components and the curved, moving skin surface.
Solution Approach 2:
The sensor design incorporates dynamic elements that can adapt to changing contact conditions during body motion. The optical path and contact interface are designed to accommodate positional changes while maintaining detection capability.
2Measurement precision
If tight contact with the skin is achieved, then detection sensitivity is improved, but noise from optical path disruption increases when motion occurs
Solution Approach 1:
The sensor establishes preliminary optical coupling between the light source and detector through the membrane structure before measurement begins. This pre-established optical path reduces the impact of subsequent motion-induced disruptions.
Solution Approach 2:
The flexible membrane serves as an intermediary element between the sensor components and the skin, maintaining optical contact while accommodating motion. It mediates the interaction between the rigid sensor and the dynamic skin surface.
3Ease of manufacture
If the sensor structure is simplified for wearable devices, then ease of manufacture is improved, but optical path control and noise reduction deteriorate
Solution Approach 1:
The flexible membrane performs multiple functions simultaneously: it maintains mechanical contact with the skin, guides the optical path, and provides structural support for the sensor components. This multi-functionality reduces the need for separate specialized components.
Solution Approach 2:
The patent combines the contact interface and optical guiding functions into a single integrated membrane structure, rather than using separate components. This merging simplifies manufacturing while maintaining optical control capability.
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
Enables stable and high-sensitivity pulse wave detection by reducing noise components and maintaining optical path integrity, even with displacement and body motion, thereby improving detection accuracy.
Implementation Method 1
a first light guide path having a reflective surface that couples the first opening with the second opening, and a second light guide path having a reflective surface that couples the third opening with the fourth opening
Implementation Method 2
a light emitting element disposed on the mounting surface separately from the light receiving element
Implementation Method 3
The photoelectric pulse wave sensor irradiates a human body surface with light emitted by a light emitting element and receives transmitted light or reflected light
Implementation Method 4
The photoelectric pulse wave sensor detects the pulse wave by using the fact that change in the amount of received light corresponds to the plethysmogram of the blood vessel
Data Source
AI summary
Provided is a pulse wave detection device including a sensor substrate having a mounting surface and a back surface, a light receiving element disposed on the mounting surface of the sensor substrate, a light emitting element disposed on the mounting surface, and a light guide part having a first opening that surrounds the light receiving element, a second opening that corresponds to the first opening and is provided at a top part of a curved surface or in a vicinity of the top part, a third opening that surrounds the light emitting element, a fourth opening that corresponds to the third opening and is provided in the curved surface, a first light guide path having a reflective surface that couples the first opening with the second opening, and a second light guide path having a reflective surface that couples the third opening with the fourth opening.