Optical Emitter Scattering Structure for Improved PPG Signal Detection
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Solution Overview
Problem
Existing photoplethysmography (PPG) systems suffer from low utilization of light sources due to most optical signals being reflected back to the light source, leading to high power consumption and limited effective signal reception by the photodetector.
Innovation Solution
An optical transmitter with an adjustment structure that scatters central light spot optical signals away from the original light spot center, converting the original light spot into a test light spot with improved light intensity distribution, allowing more effective backward signals to be received by the photodetector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the photodetector is separated from the light source by a specific distance, then the device structure is simplified, but most test optical signals are reflected back to the light source and cannot be used, resulting in low light source utilization and high power consumption
Solution Approach 1:
The patent extracts the central high-intensity light spot from the original light spot and redirects it to a specific direction away from the light source. This is achieved by using an adjustment structure that scatters only the central light spot optical signals in a direction away from the original light spot center, while leaving other regions unchanged. This selective extraction and redirection of the central light spot enables the photodetector to receive more effective backward signals without requiring complex structural modifications
Solution Approach 2:
The patent introduces an adjustment structure as an intermediary component between the light source and the skin. This adjustment structure includes scattering elements that selectively scatter the central light spot optical signals while allowing other light to pass through unchanged. The intermediary structure modifies the light distribution pattern, creating an optimized light spot that directs more light away from the light source toward the photodetector, thereby reducing energy loss without complicating the overall device structure
2Device complexity
If the photodetector is separated from the light source by a specific distance, then the device structure is simplified, but the photodetector can receive only a small quantity of effective backward reflected and scattered signals, resulting in low light source utilization
Solution Approach 1:
The patent extracts the central high-intensity light spot from the original light spot and redirects it to a specific direction away from the light source. This is achieved by using an adjustment structure that scatters only the central light spot optical signals in a direction away from the original light spot center, while leaving other regions unchanged. This selective extraction and redirection of the central light spot enables the photodetector to receive more effective backward signals without requiring complex structural modifications
Solution Approach 2:
The patent introduces an adjustment structure as an intermediary component between the light source and the skin. This adjustment structure includes scattering elements that selectively scatter the central light spot optical signals while allowing other light to pass through unchanged. The intermediary structure modifies the light distribution pattern, creating an optimized light spot that directs more light away from the light source toward the photodetector, thereby reducing energy loss without complicating the overall device structure
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
Enhances the utilization of light sources by redirecting central light spot optical signals to improve detection accuracy and reduce power consumption in photoplethysmography systems.
Implementation Method 1
the adjustment structure is configured to scatter the central light spot optical signal in a direction away from the original light spot center
Implementation Method 2
the adjustment structure includes a grating structure, configured to diffract the incident central light spot optical signal
Implementation Method 3
the adjustment structure includes a reflective film, configured to reflect the incident central light spot optical signal
Data Source
Figure 1~2
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AI summary
This application provides an optical transmitter (31) and a photosensitive apparatus (20) used for photoplethysmography. The optical transmitter (31) includes a light source (311) and an adjustment structure. The light source (311) is configured to output an original light spot (101), to transmit a test optical signal (B1, B2) to a skin of a user. The adjustment structure is located on an output optical path of the test optical signal (B 1, B2). A test optical signal transmitted from an original light spot center (1011) of the original light spot (101) is a central light spot optical signal, and the adjustment structure is configured to scatter the central light spot optical signal in a direction away from the original light spot center (1011), to convert the original light spot (101) into a test light spot, that is, adjust a light intensity distribution of the light spot, so that the photodetector (33) can receive more effective backward signals, to reduce a loss of the light source.