Light Distance Measurement Device with Dynamic Sensitivity Adjustment
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Solution Overview
Problem
Conventional light distance measurement devices using SPADs for distance calculation often suffer from saturation issues due to unnecessary reflected light, leading to errors in determining the target's position, especially when the measuring range is extended.
Innovation Solution
The device employs a matrix of photodetectors with a level adjustment unit that changes the irradiation intensity or detection sensitivity between normal and suppression levels, allowing for the differentiation between target-reflected light and unnecessary reflected light by analyzing pulse information at both levels, thereby reducing the risk of incorrect distance calculations without reducing the measuring range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the measuring range is extended, then the detection capability for distant targets is improved, but saturation errors due to unnecessary reflected light increase
Solution Approach 1:
The patent dynamically adjusts the detection sensitivity of the photodetectors based on the measured distance. When the target is far away, the detection sensitivity is increased to capture weak reflected light signals. When the target is close, the detection sensitivity is decreased to avoid saturation from strong signals and unnecessary reflected light. This dynamic adjustment resolves the contradiction by adapting the system parameters to the specific measurement conditions.
Solution Approach 2:
The patent changes the detection sensitivity parameter of the photodetectors according to the distance to the target. By adjusting this parameter, the system can maintain optimal measurement precision across different ranges, preventing saturation errors while extending the measurable distance range.
2Length of stationary object
If the irradiation intensity is increased to improve detection of distant targets, then the measuring range is extended, but saturation due to unnecessary reflected light occurs
Solution Approach 1:
The patent dynamically adjusts both the irradiation intensity and detection sensitivity based on the target distance. For distant targets, both are increased to ensure sufficient signal strength. For close targets, both are decreased to prevent saturation. This coordinated dynamic adjustment resolves the contradiction between extending measuring range and avoiding saturation.
Solution Approach 2:
The system uses feedback from the detected light signal strength to adjust the irradiation intensity and detection sensitivity. When saturation is detected or anticipated (based on distance), the system reduces the irradiation intensity or detection sensitivity to eliminate the harmful saturation effect while maintaining the ability to measure distant targets.
3Length of stationary object
If the detection sensitivity is increased to detect weak signals from distant targets, then the measuring range is extended, but the likelihood of saturation from unnecessary light increases
Solution Approach 1:
The patent dynamically adjusts the detection sensitivity of the photodetectors based on the distance to the target. For distant targets where weak signals are expected, the detection sensitivity is increased to ensure reliable detection. For close targets where strong signals are expected, the detection sensitivity is decreased to prevent saturation and maintain calculation accuracy. This dynamic parameter adjustment resolves the contradiction between extending range and maintaining reliability.
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 effectively reduces the likelihood of saturation and allows for accurate distance measurement by distinguishing between target-reflected light and unnecessary light, enabling reliable detection of both near and distant targets without extending the measuring range.
Implementation Method 1
The photodetectors is arranged in a matrix and responds to the sensing light
Implementation Method 2
The level adjustment unit changes an irradiation intensity of the sensing light output from the irradiation unit or detection sensitivity of the photodetectors from a normal level to a suppression level
Data Source
AI summary
A light distance measurement device detects a distance to a target. The light distance measurement device includes an irradiation unit, photodetectors, a level adjustment unit, a peak detection unit, a pulse information acquisition unit, and a distance calculation unit. The irradiation unit irradiates sensing light in a detection target direction. The photodetectors is arranged in a matrix and responds to the sensing light. The level adjustment unit changes an irradiation intensity of the sensing light or detection sensitivity of the photodetectors. The peak detection unit detects a received light pulse and a peak of the received light pulse. The pulse information acquisition unit acquires, as pulse information, a data set indicating a predetermined feature amount related to the received light pulse. The pulse information includes normal and suppression pulse information. The distance calculation unit calculates a distance value to the target based on the normal and suppression pulse information.