SPAD Proximity Sensor Dynamic Pulse Adjustment
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Solution Overview
Problem
Current proximity detection systems using single photon avalanche diodes (SPADs) require users to set a fixed number of LED pulses to achieve a desired quality for accurate range readings, which is not applicable in all conditions and can lead to inefficiencies in power consumption and user setup.
Innovation Solution
A proximity detection apparatus and method utilizing an array of SPADs and an illumination source, where the system automatically adjusts the number of LED pulses based on a quality metric to ensure a predetermined level of illumination, thereby calculating the target's proximity only when the quality threshold is met, eliminating the need for user-defined accumulation periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed number of LED pulses is set to achieve desired quality for accurate range readings, then measurement precision is improved, but device complexity and ease of operation deteriorate due to user setup requirements
Solution Approach 1:
The system automatically determines the number of LED pulses required by monitoring the quality metric (number of detected photon events) and dynamically adjusting the pulse count until the predetermined quality threshold is achieved. This self-adjusting mechanism eliminates the need for manual user setup while maintaining accurate range readings.
Solution Approach 2:
The system implements a feedback loop where the quality metric from detected photon events is continuously monitored and used to adjust the number of LED pulses. When the quality metric indicates insufficient data, the system automatically increases the pulse count; when the threshold is met, it stops, ensuring optimal measurement precision without user intervention.
2Measurement precision
If a fixed number of LED pulses is set to achieve desired quality, then measurement precision is improved, but use of energy deteriorates due to inefficient power consumption
Solution Approach 1:
The system dynamically adjusts the number of LED pulses based on real-time quality metrics rather than using a fixed predetermined number. This dynamic adaptation allows the system to consume only the necessary amount of energy required to achieve the desired measurement precision, avoiding waste from excessive pulsing in favorable conditions.
Solution Approach 2:
The system changes the operational parameter (number of LED pulses) based on the quality metric feedback. By adjusting this parameter dynamically according to detected photon event quality, the system optimizes energy consumption while maintaining measurement accuracy across varying environmental conditions.
3Device complexity
If a fixed number of LED pulses is used, then device complexity is reduced, but adaptability deteriorates as the system cannot adjust to different lighting conditions
Solution Approach 1:
The system automatically adapts to different lighting conditions by monitoring the quality metric and self-adjusting the number of LED pulses required. This self-service capability enables the system to handle varying environmental conditions without requiring complex preconfiguration or user input, maintaining low device complexity while achieving high adaptability.
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 approach reduces user setup and power consumption by dynamically adjusting the number of LED pulses needed to achieve a valid range value, improving efficiency and reducing latency, especially in low-light conditions or with reflective targets close to the sensor.
Implementation Method 1
The initiating charge carrier can be photo-electrically generated by means of a single incident photon striking the high field region
Implementation Method 2
The high reverse bias voltage generates a sufficient magnitude of electric field such that a single charge carrier introduced into the depletion layer of the device can cause a self-sustaining avalanche via impact ionization
Data Source
AI summary
A proximity detector may include an array of single photon avalanche diodes (SPADs) and an illumination source. Illumination from the illumination source may be reflected by a target to the array of single photon avalanche diodes. The SPADs may be operable to detect events. A number of events detected may be dependent on a level of illumination incident on the SPADs. The proximity detector may then determine a quality metric and calculate an output when the quality metric is at a predetermined level. A related method may include regulating the quality of the data on which such a proximity detector apparatus calculates its output.