Reference Optical Path Distance Correction for Temperature Drift
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Solution Overview
Problem
Existing methods for non-contact distance measurement using a light beam are hindered by changes in the surrounding environment, such as temperature, leading to inaccurate measurements due to the need for temperature stabilization units and increased size and cost.
Innovation Solution
A distance measurement system incorporating a first and second light-receiving unit, a temperature sensor, and a correction unit to adjust measured distances based on assessed temperature changes, using a frequency modulated continuous wave method and swept-source optical coherence tomography for accurate distance calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature stabilization units (heater, cooler, temperature controller) are added to stabilize the optical path temperature, then measurement accuracy is improved, but device complexity and size increase
Solution Approach 1:
The patent replaces the mechanical/thermal stabilization system (heaters, coolers, temperature controllers) with an optical measurement and correction system. By using a reference optical path to measure temperature-induced length changes and applying software correction, the system achieves accurate distance measurement without complex thermal control hardware.
Solution Approach 2:
The patent introduces a reference optical path as an intermediary element that experiences the same temperature changes as the measurement optical path. This reference path serves as a mediator to detect and quantify temperature effects, enabling correction of measurement errors without directly controlling the temperature.
2Measurement precision
If temperature stabilization units are added to stabilize the optical path temperature, then measurement accuracy is improved, but the time required for temperature stabilization increases
Solution Approach 1:
The patent performs preliminary measurement of the reference optical path length at different temperatures to establish a correction relationship before actual distance measurements. This preliminary characterization allows the system to immediately apply corrections during operation without requiring time-consuming temperature stabilization.
Solution Approach 2:
The patent replaces the time-consuming thermal stabilization process with real-time optical measurement and computational correction, eliminating the waiting period required for temperature equilibrium while maintaining measurement accuracy.
3Measurement precision
If temperature stabilization units are added to stabilize the optical path temperature, then measurement accuracy is improved, but system cost increases
Solution Approach 1:
The patent replaces expensive thermal control hardware (heaters, coolers, temperature controllers, insulation) with cost-effective optical components and software processing. The reference optical path and correction algorithm provide a low-cost alternative to active temperature stabilization systems.
Solution Approach 2:
The patent uses simple, inexpensive temperature sensors and standard optical components rather than expensive precision thermal control systems. The correction approach uses readily available off-the-shelf components to achieve high measurement accuracy at low cost.
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 distance correction in varying environments by monitoring and compensating for temperature changes, reducing system size and cost through efficient temperature management.
Implementation Method 1
a first light-receiving unit configured to irradiate an object with one part of a split light beam as assessment light, and receive light reflected by the object to detect a target assessment beat signal; a second light-receiving unit configured to guide the other part of the split light beam as reference light to a reference optical path serving as a distance reference, and receive the reference light that has passed through the reference optical path to detect a reference optical path assessment beat signal
Implementation Method 2
a temperature sensor configured to assess a temperature in the periphery of the reference optical path
Implementation Method 3
it is known that, in a case where a reference optical path length serving as a distance reference is changed due to a change in the surrounding environment such as a temperature
Data Source
AI summary
According to the present invention, a measured distance is corrected in accordance with change in the surrounding environment. A distance measurement system includes: a first light-receiving unit configured to irradiate an object with one part of a split light beam as assessment light, and receive light reflected by the object to detect a target assessment beat signal; a second light-receiving unit configured to guide the other part of the split light beam as reference light to a reference optical path serving as a distance reference, and receive the reference light that has passed through the reference optical path to detect a reference optical path assessment beat signal; a distance measurement unit configured to measure a distance to the object on the basis of the target assessment beat signal and the reference optical path assessment beat signal; a temperature sensor configured to assess a temperature in the periphery of the reference optical path; and a correction unit configured to correct the measured distance on the basis of the assessed temperature.