Distance Sensor Timing Circuit With TDC Delay Line Correction
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Solution Overview
Problem
Existing sensor devices face challenges in improving measurement precision of distance or distance change to an object without increasing circuit scale, particularly due to the need for numerous delay circuits and temperature variations affecting measurement accuracy.
Innovation Solution
The sensor device employs a TDC delay line measurement unit with temperature correction, combining counter measurement for rough estimation and TDC delay lines for fine measurement, using a FPGA with integrated circuits to enhance precision without increasing circuit scale.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the distance range is extended by adding more delay circuits, then the measurement range is improved, but the circuit scale and logical capacity increase
Solution Approach 1:
The patent combines multiple delay circuits into a single delay line structure where delay elements are connected in series. This merging approach allows the system to achieve extended delay ranges without proportionally increasing the overall circuit scale, as the delay functions are integrated into a unified structure rather than distributed across separate parallel circuits.
Solution Approach 2:
The delay line is divided into multiple discrete delay elements connected in series, each contributing a specific delay amount. This segmentation allows the system to extend the total delay range by adding individual elements while maintaining a compact overall structure, avoiding the need to redesign the entire circuit when expanding the measurement range.
2Length of stationary object
If the number of delay circuits is increased to extend distance range, then the measurement range is improved, but variations in measurement results due to temperature increase
Solution Approach 1:
The patent incorporates a temperature detection circuit that continuously monitors the temperature of the delay line and feeds this information back to a correction circuit. This feedback mechanism enables real-time detection of temperature-induced variations and triggers appropriate correction actions to maintain measurement precision across different temperature conditions.
Solution Approach 2:
The system dynamically adjusts the delay characteristics by applying correction values based on temperature measurements. When temperature variations are detected, the correction circuit modifies the delay parameters to compensate for thermal effects, thereby maintaining consistent measurement precision across varying temperature conditions without requiring additional physical delay circuits.
3Measurement precision
If the number of times of sampling is increased to improve measurement precision, then the measurement precision is improved, but the circuit scale increases
Solution Approach 1:
The patent implements a continuous sampling mechanism where the delay line operates continuously with multiple sampling points along its length. This allows the system to perform multiple measurements within a single operational cycle without requiring separate sampling circuits for each measurement, thereby improving precision while maintaining a compact circuit scale.
Solution Approach 2:
Instead of increasing the number of separate sampling circuits in the traditional dimension, the patent utilizes the temporal dimension by implementing continuous sampling along the delay line. Multiple sampling points are distributed along the length of the delay line, allowing simultaneous multi-point sampling that improves precision without proportionally increasing circuit 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
This approach allows for precise measurement of distance and distance change with high resolution and reduced temperature variations, enabling accurate detection over a wide range without requiring additional resources.
Implementation Method 1
a light projection element that projects detection light toward an object, and a light reception element that receives reflected light of the detection light
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3
AI summary
This sensor device for measuring the distance to an object is provided with: a light projection unit that repeatedly emits detection light toward the object; a light reception unit that receives reflected light of the detection light, and outputs a binarized light reception signal; a projection light oscillation unit that controls emission of the detection light, and outputs a start signal synchronized with the emission of the detection light; a count measurement unit that starts counting of the light reception signal after reception of the light reception signal and the start signal, and outputs a stop signal corresponding to a feature point of the light reception signal; a delay line measurement unit that outputs a delay line output signal corresponding to the delay time of the light reception signal near the feature point of the light reception signal after reception of the light reception signal and the stop signal; and a distance calculating unit that calculates the distance to the object on the basis of the delay line output signal.