Optical Sensor Layout for Reflectance-Independent Proximity Detection
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Solution Overview
Problem
Existing optical sensors struggle to accurately detect the proximity of objects regardless of their reflectance, as the amount of reflected light varies significantly based on the object's surface properties, making it difficult to distinguish between approaching and contacting states.
Innovation Solution
An optical sensor design featuring a light source, a light receiver, and a convex portion that blocks reflected light when the object is within a specific threshold distance, allowing for proximity detection independent of object reflectance, with the threshold distance set to less than 10% of the optical output power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amount of reflected light is used as the detection signal, then the sensor can detect objects, but the detection accuracy deteriorates because the reflected light amount varies with object reflectance
Solution Approach 1:
The patent introduces a convex portion as an intermediary element that blocks reflected light from reaching the light receiver when the object is within a predetermined distance. This mediator creates a geometric relationship between the light source, convex portion, and light receiver, allowing proximity detection based on light blocking rather than light reflection intensity, thereby eliminating dependence on object reflectance
Solution Approach 2:
The patent transitions from detecting proximity based on light intensity (one-dimensional measurement) to detecting proximity based on geometric spatial relationships (three-dimensional configuration). By arranging the light source, convex portion, and light receiver in specific spatial positions, the system detects proximity through the presence or absence of blocked light paths rather than through reflected light intensity variations
2Measurement precision
If a convex portion is added to block reflected light, then proximity detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent applies local quality by adding the convex portion only in the specific region where light blocking is needed, rather than redesigning the entire sensor structure. The convex portion is strategically positioned between the light source and light receiver to create the necessary optical path blocking, minimizing structural changes while achieving the desired detection functionality
Solution Approach 2:
The patent merges the proximity detection function with the existing sensor housing or mounting structure by integrating the convex portion into the sensor body. This combination approach allows the convex portion to serve dual purposes: maintaining structural integrity and providing the necessary light blocking function, thereby reducing overall device complexity
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 accurate detection of object proximity at a specific distance without relying on object reflectance, improving the precision of proximity and contact force sensing in applications like robot hands.
Implementation Method 1
The light receiver receives reflected light of the emitted light being reflected by the object
Data Source
AI summary
An optical sensor includes a light source, a light receiver, and a convex portion. The light source emits light to an object. The light receiver receives reflected light of the emitted light reflected by an object and generates a signal showing a light reception result. The convex portion has a height higher than a height of the light source and the light receiver. The convex portion is between the light source and the light receiver to block reflected light from the light receiver when light from the light source is reflected within a range of a predetermined distance from the convex portion. The light receiver outputs a signal to show a light reception result of equal to or less than a threshold amount of light indicating that the reflected light is not received in response to proximity of the object being within a range of a predetermined distance.