Optical Gas Sensor With Folded Light Path
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Solution Overview
Problem
Existing optical devices for gas sensing face challenges in achieving a smaller package size due to the long path of the light beam and greater thickness, which complicates the formation of a compact design.
Innovation Solution
The optical device incorporates a carrier, a light source, a die, a light guiding structure, and a reflecting structure, where the light guiding structure and reflecting structure define a chamber with a vent hole, allowing the light beam to be reflected and guided efficiently, thereby shortening the light path and reducing the package thickness. The light guiding structure includes a non-air medium and a reflecting layer for total reflection, and the reflecting surface is sloped to direct the light beam back to the die, reducing the overall package size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a reflecting structure is used for gas sensing, then the light beam path length increases, but the package thickness increases and device size becomes larger
Solution Approach 1:
The patent transitions from a planar light path to a three-dimensional folded light path using multiple reflecting surfaces. The light beam is directed through multiple reflections at angled surfaces (45-degree angles) to achieve extended path length within a compact vertical stack, effectively utilizing the third dimension to resolve the contradiction between path length and package footprint.
Solution Approach 2:
The patent implements a nested arrangement where multiple optical components (light sources, dies, reflecting structures) are stacked vertically one above another. The light path folds through this nested structure, allowing the light beam to traverse through multiple sensing regions in sequence, achieving long path length while maintaining a compact overall package volume.
2Measurement precision
If the light beam path is extended for better gas sensing, then the package thickness increases, making it difficult to form a smaller package size
Solution Approach 1:
The patent uses vertical stacking of optical components along the z-axis to achieve extended light interaction path without increasing the x-y plane footprint. The light beam propagates through multiple vertically arranged sensing regions via reflections, enabling improved gas sensing accuracy while maintaining thin package profile.
Solution Approach 2:
The patent employs adjustable light path configuration through movable or adjustable reflecting elements that can optimize the light beam trajectory. This dynamic adjustment allows the system to achieve optimal sensing path length while adapting to different package thickness requirements, maintaining measurement precision across varying form factors.
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 effectively reduces the package height of the optical device while maintaining efficient light interaction with gases, allowing for accurate gas sensing by the die, thereby addressing the challenge of compact design without compromising sensing capabilities.
Implementation Method 1
The reflecting structure comprises a light reflecting surface facing the light exit surface of the light guide structure and is configured to reflect the light beam exiting from the light exit surface to the die
Implementation Method 2
The light guiding structure includes a non-air medium and a reflecting layer for total reflection
Data Source
AI summary
An optical device includes a carrier, a light source, a die, a light guiding structure and a reflecting structure. The carrier has a surface. The light source is disposed on the surface and configured to emit a light beam. The die is disposed on the surface and configured to sense the light beam. The light guiding structure is disposed on the surface and configured to guide the light beam. The light guiding structure includes a light receiving surface facing the light source and a light exit surface. The reflecting structure is disposed over the die. The reflecting structure includes a light reflecting surface facing the light exit surface of the light guide structure and is configured to reflect the light beam exiting from the light exit surface to the die. The light reflecting surface and the light exit surface are separated from each other and define a vent hole.