Distance Sensor Using PSD for Low Reflectivity Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional infrared sensors in sanitary automation fail to detect objects with low infrared reflectivity, such as black clothing or hair, and also experience sensing failures when objects are too close to the sensor, leading to incorrect operation of sanitary ware.
Innovation Solution
A distance detecting sensor system that includes an infrared light emitting source, a receiving unit, and a close range light emitting source, where the emission power and frequency are adjusted based on the presence of an object, and a photo-electric device sensitive to the position of incident light is used to calculate the object's distance, ensuring reliable detection and preventing mirror interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional infrared sensors are used for automatic sensing, then sensing can be achieved for most objects, but sensing fails for objects with low infrared reflectivity (e.g., black clothing, hair)
Solution Approach 1:
The patent changes the detection parameter from infrared reflectivity judgment to distance measurement. By using a position-sensitive detector to measure the position of the light spot formed by reflected light, the system calculates distance based on geometric relationships, thereby avoiding the problem of low infrared reflectivity objects failing to be detected
Solution Approach 2:
The patent replaces the conventional infrared detection method (which relies on detecting reflected infrared radiation intensity) with an optical geometric measurement method using a position-sensitive detector. This substitution transforms the detection mechanism from intensity-based to position-based measurement, enabling reliable detection of objects with low infrared reflectivity
2Measurement precision
If a distance detecting sensor using triangular measurement principle is used, then accurate distance measurement can be achieved, but detection fails when objects are too close to the sensor
Solution Approach 1:
The patent segments the detection space into different distance ranges and uses different light emitting sources for different ranges. A first light emitting source is used for normal distance detection, while a second light emitting source with different emission characteristics is used for close-range detection, thereby resolving the detection failure at close distances
Solution Approach 2:
The patent dynamically switches between different light emitting sources based on the detection distance. The system adjusts which light source is active according to the object's distance from the sensor, optimizing detection performance for both close-range and normal-range objects
3Reliability
If infrared emission power is increased to improve detection of low reflectivity objects, then detection sensitivity improves, but energy consumption increases
Solution Approach 1:
The patent dynamically adjusts infrared emission by using different light emitting sources for different detection scenarios. The system activates specific light sources based on detection needs and object distance, avoiding continuous high-power emission and thereby reducing overall energy consumption while maintaining detection sensitivity when needed
Solution Approach 2:
The patent changes emission parameters by using different light emitting sources with different characteristics for different detection requirements. Instead of continuously increasing power, the system selects appropriate sources based on the specific detection scenario, optimizing the balance between detection sensitivity and energy consumption
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 system effectively overcomes sensing failures by reliably detecting objects within a preset range, improving detection performance and preventing incorrect operation of sanitary ware, especially when objects are close to the sensor.
Implementation Method 1
a light emitting source S1, a receiving unit P1, an emitting lens L1 and a receiving lens L2 arranged in front of the light emitting source S1 and the receiving unit P1 respectively to focus infrared light
Implementation Method 2
the infrared light is reflected from human body and the signal strength of the reflected signal is judged after being received by an infrared receiver
Implementation Method 3
the light emitted from the light emitting source S1 is focused by a lens L1 and then projected onto the surface of an object O1 to be detected. The reflected light is focused by a lens L2 onto a one dimensional PSD
Implementation Method 4
a position detecting sensor, or called as position sensitive detector (PSD) is a photoelectric device that is sensitive to the position of incident light
Data Source
AI summary
The present invention discloses a distance detecting sensor. The distance detecting sensor includes a casing, a focusing lenses, a circuit board mounted with several electronic elements, an emitting device for emitting infrared light, and a receiving device for receiving and sensing a reflected infrared light. The distance detecting sensor is configured to have a high detection accuracy and improved detection performance.