Optical Sensor Light Guide Structure for Detection Accuracy
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Solution Overview
Problem
Conventional optical sensors lack an effective light guiding structure, which affects their performance in directing light emitted by light emitting units towards external objects for accurate detection.
Innovation Solution
The optical sensor incorporates a substrate with a light guide structure featuring an inner and outer light reflecting portion, guiding light emitted by light emitting units onto a predetermined reference axis, ensuring it is reflected towards an external object and detected by a photodetector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no light guide structure is used in the optical sensor, then the device complexity is reduced, but the measurement precision and light detection accuracy deteriorate
Solution Approach 1:
The light guide structure is segmented into multiple functional portions: an inner light guide portion with a first refractive index, an outer light guide portion with a second refractive index, and a light reflecting portion. This segmentation allows each portion to perform its specific function optimally, improving light direction control and detection accuracy without requiring a completely complex new structure.
Solution Approach 2:
Different portions of the light guide structure have different local optical properties (refractive indices). The inner light guide portion has a first refractive index optimized for light emission guidance, while the outer light guide portion has a second refractive index optimized for light reflection guidance. This local quality differentiation improves overall light direction control precision.
2Measurement precision
If a light guide structure with multiple portions is introduced, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The light guide structure merges multiple functions into a single integrated component: light emission guidance, light reflection guidance, and light direction control are all performed by the light guide structure itself rather than requiring separate components. This merging improves precision while limiting the increase in device complexity.
Solution Approach 2:
Instead of using complex external optical systems to guide light, the patent inverts the approach by making the substrate itself the light guide through material composition control. The light guide structure is formed by controlling the composition of the substrate material, turning a potential limitation (substrate material) into a functional advantage.
3Ease of manufacture
If the light guide structure uses uniform material composition, then the manufacturing process is simplified, but the light direction control precision deteriorates
Solution Approach 1:
The patent changes the material composition parameter of the substrate to create regions with different refractive indices. By controlling the composition of the light guide structure (inner portion, outer portion, and reflecting portion), the patent achieves precise light direction control while maintaining a relatively simple manufacturing process that only requires material composition control rather than complex multi-material assembly.
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 configuration enhances the accuracy of light reflection and detection, improving the overall performance of the optical sensor by concentrating light onto a central axis, thereby enhancing biomedical signal acquisition such as photoplethysmography (PPG) and blood oxygen concentration monitoring.
Implementation Method 1
The inner light reflecting portion and the outer light reflecting portion enable light emitted by the light emitting units to be reflected towards an external object
Data Source
AI summary
An optical sensor includes a substrate, light emitting units for emitting light with different wavelengths, and a photodetector. The substrate has at least one receiver for containing these light emitting units and a slot for containing the photodetector. A light guide structure of the optical sensor can be the receiver with a specific design, so that the light emitted by the light emitting units can be reflected towards a central axis of the photodetector. Thus, when at least one of the light emitting units emits light onto an object, the photodetector can receive the light reflected from the object.