Spheroid Optical Cover for Droplet Sensor Detection
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Solution Overview
Problem
Existing droplet sensors face challenges in achieving high sensitivity and wide detection areas due to complex optical path configurations and manufacturing difficulties, leading to decreased detection accuracy and increased sensitivity variations based on raindrop position.
Innovation Solution
A droplet sensor design featuring an optical cover forming part of a spheroid with a light emitting and receiving device positioned offset from the first focal point and a reflector near the second focal point, utilizing total internal reflection conditions at the gas interface but not at the liquid interface to enhance detection accuracy and simplify configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a refraction optical element is used to collimate light beams and expand detection area, then the detection area is expanded, but the optical element becomes complicated in shape and difficult to manufacture and install
Solution Approach 1:
The patent uses a spherical optical cover instead of a complex refraction optical element. The spherical shape naturally focuses and directs light beams through its curved surface, achieving collimation and wide detection area without requiring complicated segmented structures. The spherical geometry is simple to manufacture while providing the necessary optical functionality.
Solution Approach 2:
The spherical optical cover serves multiple functions simultaneously: it acts as a protective cover, a light collimating element, and a detection area expander. This single component replaces what would otherwise require multiple separate optical elements, simplifying the overall structure while maintaining expanded detection capability.
2Measurement precision
If light is reflected multiple times to increase sensitivity, then sensitivity is improved, but the optical path length increases and sensitivity varies depending on raindrop position
Solution Approach 1:
The spherical optical cover creates a uniform optical path where light beams travel through the sphere and are reflected by a planar reflector. This geometry ensures that all light beams, regardless of their entry point on the detection area, follow similar path lengths and angles, eliminating position-dependent sensitivity variations while maintaining consistent optical paths.
Solution Approach 2:
The patent introduces asymmetry by positioning the light emitting and receiving device at an offset from the focal point along the major axis, and placing the planar reflector at a specific distance from the spherical cover. This asymmetric configuration optimizes the optical path to achieve uniform sensitivity across the detection area while controlling the number and type of reflections.
3Area of stationary object
If a complicated refraction optical element is divided into multiple areas to expand detection area, then the detection area is expanded, but the element becomes difficult to fix and install
Solution Approach 1:
The patent divides the detection area into multiple regions (first detection area, second detection area, third detection area) on the spherical optical cover's surface. Each region corresponds to different light beam incident angles and reflection patterns, allowing the system to detect droplets across a wide area using a single integrated optical path configuration rather than multiple separate optical elements.
Solution Approach 2:
The spherical geometry naturally distributes the detection area across its curved surface, with different zones detecting light at different angles. This curved surface configuration is simple to manufacture as a single piece and easy to install, replacing complex segmented refraction elements while achieving the same wide detection coverage.
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 design enables accurate and efficient detection of droplets across a wide area with improved sensitivity, regardless of raindrop position, by leveraging the spheroid's optical properties to differentiate between gas and liquid interfaces, thus enhancing detection precision and ease of manufacturing.
Implementation Method 1
The effective detection area satisfies a total internal reflection condition at an interface with a gas
Implementation Method 2
The reflector reflects, towards a light receiving surface of the light emitting and receiving device, light totally reflected by the effective detection area
Data Source
AI summary
A droplet sensor includes an optical cover that forms part of a spheroid, a major axis of the spheroid being a vertical axis, a light emitting/receiving device disposed at a position offset from a first focal point of the spheroid along the major axis, and a reflector disposed in vicinity of a second focal point of the spheroid. The optical cover has an effective detection area between the light emitting/receiving device and the reflector. The effective detection area satisfies a total internal reflection condition at an interface with a gas, and does not satisfy the total internal reflection condition at an interface with a liquid. The reflector reflects, towards a light receiving surface of the light emitting/receiving device, light totally reflected by the effective detection area, or reflects, towards the effective detection area, light directly incident on the reflector from the light emitting/receiving device.