Optical Fiber Reflective Surface for Short-Range Distance Measurement
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Solution Overview
Problem
Existing optical distance meters face challenges in maintaining accuracy under temperature variations, vibrations, and at very short distances due to non-coincident optical input and output surfaces, leading to large measurement errors, especially at long distances.
Innovation Solution
A device with an optical fiber and a main lens system where laser radiation is emitted and received on the same surface, using a reflective layer on the decoupling surface of the optical fiber, and a non-perpendicular angle configuration to optimize calibration and reduce environmental influence, combined with a single mode polarization-maintaining fiber and diffuse calibration signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate optical input and output surfaces are used, then the device can be designed with distinct transmit and receive channels, but the device cannot measure at very short distances
Solution Approach 1:
The patent merges the optical input and output surfaces by using a single optical fiber face for both laser radiation emission and reflected light reception. This is achieved by placing a beam splitter at a 45-degree angle to the optical fiber output, which directs the outgoing laser beam perpendicular to the fiber axis while allowing the reflected beam to return to the detector through the same fiber face, enabling short distance measurements
2Measurement precision
If calibration is performed with identical reference and measurement channels, then measurement accuracy is optimized, but temperature variations cause measurement errors
Solution Approach 1:
The patent applies local quality by creating a temperature-compensated reference channel that is physically separated from the measurement channel. The reference channel uses a separate optical path with its own beam splitter and detector, allowing it to experience the same temperature variations as the measurement channel while maintaining a stable reference signal for continuous calibration
3Device complexity
If the optical fiber output is directly aligned with the main lens, then the device structure is simplified, but adjustment from transmit axis to receive axis is necessary
Solution Approach 1:
The patent uses another dimension by introducing a beam splitter positioned at a 45-degree angle to the optical fiber axis. This redirects the laser beam perpendicular to the fiber axis while maintaining the optical fiber's physical orientation, eliminating the need for axis adjustments between transmit and receive paths
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 measurement at short distances and reduces measurement errors by stabilizing temperature effects and minimizing signal attenuation, while allowing for compact and efficient device design.
Implementation Method 1
a reflective layer, in particular an annular reflective layer, is arranged on the decoupling surface
Implementation Method 2
The decoupling surface can be arranged at a non-perpendicular angle to the optical axis of the optical fiber
Implementation Method 3
The optical fiber can be a single mode optical fiber and, in particular, a polarization-maintaining fiber
Implementation Method 4
Optical distance meters based on laser measurement are known from the prior art. Such distance meters use the time-of-flight (TOF) principle or phase modulation as measuring techniques
Data Source
AI summary
A device (1) for measuring a distance of an object at which laser radiation modulated and emitted by the device (1) are reflected is disclosed. The device comprises an optical fiber (2) into which laser radiation can be coupled and a main lens (3) through which the laser radiation can be emitted along an optical axis (4) of the main lens. The optical fiber (2) comprises a decoupling surface (5), wherein a reflective layer (6), in particular an annular surface, is arranged on the decoupling surface (5).