Light Sensor Using Multi-Wavelength Emission for Object Type Identification
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Solution Overview
Problem
Current light sensors cannot accurately determine the type of an object using light intensity, requiring additional sensors like capacitance or temperature sensors, which increases costs and complexity.
Innovation Solution
A light sensor system comprising multiple light-emitting elements with different wavelength ranges, controlled sequentially to emit signals, allowing a single light-sensing element to differentiate object types based on reflected signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors (capacitance or temperature sensors) are used to judge the type of approaching object, then the accuracy of object type identification is improved, but the device complexity and cost increase
Solution Approach 1:
The light sensor system is designed to perform multiple functions: it not only detects the distance of approaching objects but also identifies the type of objects (human skin, glass, plastic, metal, etc.) by analyzing reflection characteristics across different wavelength ranges. This multi-functionality eliminates the need for separate capacitance or temperature sensors, reducing device complexity while maintaining identification accuracy
Solution Approach 2:
The system changes the parameter of light wavelength by using multiple light-emitting elements with different peak wavelengths (e.g., 850nm, 940nm, 1300nm, 1550nm). By measuring reflection intensities across these different wavelength parameters, the system can distinguish between different object types based on their unique spectral reflection characteristics, achieving accurate identification with a single sensor type
2Adaptability or versatility
If multiple light-emitting elements with different wavelengths are used to identify object types, then the object type identification capability is improved, but the device complexity increases
Solution Approach 1:
The light source is segmented into multiple light-emitting elements, each emitting at a specific peak wavelength (e.g., 850nm, 940nm, 1300nm, 1550nm). This segmentation allows the system to probe different spectral characteristics of objects, enhancing identification capability while keeping each individual light-emitting element simple and manageable
Solution Approach 2:
The control circuit acts as an intermediary that coordinates the sequential operation of multiple light-emitting elements and processes the reflection signals from the light-sensing element. It implements the wavelength-matching algorithm that compares reflection intensities across different wavelengths to identify object types, thereby managing the complexity of multiple light-emitting elements through intelligent control
3Device complexity
If light intensity alone is used to judge object distance, then the simplicity of the system is maintained, but the ability to identify object types is lost
Solution Approach 1:
The system transitions from a one-dimensional measurement (light intensity for distance only) to a multi-dimensional measurement by incorporating wavelength as an additional dimension. By measuring reflection intensities across multiple wavelength dimensions, the system simultaneously extracts both distance information and object type information, preventing information loss while maintaining relative system simplicity
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 type identification of objects without additional sensors, reducing costs and enhancing functionality in electronic devices.
Implementation Method 1
When the light emitted by the first light-emitting element and the second light-emitting element is reflected by an object and received by the light-sensing element
Data Source
AI summary
A light sensor and a control method thereof are revealed. The light sensor comprises a first light-emitting element, a second light-emitting element and a light-sensing element. The first light-emitting element is used to generate a first emitting signal. The first emitting signal has an optical wavelength within a first wavelength range. The second light-emitting element is used to generate a second emitting signal. The wavelength of the second emitting signal has an optical wavelength within a second wavelength range. The first wavelength range is different from the second wavelength range. Thereby, a control circuit sequentially controls the first light-emitting element and the second light emitting-element to emit the first emitting signal and the second emitting signal. When the first emitting signal and the second emitting signal are reflected by an object and received by the light-sensing element, the control circuit may determine the type of the object based on the signal sensed by the light-sensing element.