Laser Interferometer Light Shielding Stabilizes Oscillation
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Solution Overview
Problem
Existing laser vibrometers face issues with unstable laser oscillation due to return light, leading to decreased signal-to-noise ratio and measurement accuracy of vibration speed.
Innovation Solution
A laser interferometer configuration that includes a laser light source, a light shielding element with a controlled opening, an optical modulator to generate reference light, and a light receiving element to detect object light and reference light, ensuring that the return light is effectively shielded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laser light source is used without return light shielding, then the device structure is simple, but the laser oscillation becomes unstable due to return light entry
Solution Approach 1:
The patent extracts and removes the harmful return light from the optical system by introducing a light shielding element with a specific opening structure. This element selectively blocks return light while allowing the laser beam to pass through, thereby eliminating the instability caused by return light entry without fundamentally changing the overall device architecture.
Solution Approach 2:
The light shielding element acts as an intermediary component between the laser light source and the rest of the optical system. It mediates the interaction by allowing the useful laser light to pass through while blocking the harmful return light, thus stabilizing laser oscillation without requiring complete redesign of the optical path.
2Measurement precision
If return light is not shielded, then the device complexity is low, but the signal-to-noise ratio decreases due to laser oscillation instability
Solution Approach 1:
The patent removes the source of noise (return light) from the optical system using a light shielding element. By extracting this harmful factor, the signal-to-noise ratio improves significantly, enabling more precise vibration speed measurements without requiring complex signal processing to compensate for noise.
Solution Approach 2:
The light shielding element is a simple, inexpensive component that provides substantial improvement in signal quality. Rather than investing in complex noise cancellation systems, the patent uses this simple disposable-like element to eliminate the noise source entirely, achieving high measurement precision cost-effectively.
3Measurement precision
If return light enters the laser light source, then no additional components are needed, but the phase of oscillated laser light becomes discontinuous
Solution Approach 1:
The patent extracts return light from the optical path using a light shielding element with a specifically designed opening. This extraction prevents return light from causing phase discontinuities in the laser oscillation, ensuring continuous and stable phase information for accurate vibration measurement without requiring complex phase correction algorithms.
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
The proposed configuration stabilizes laser oscillation, improves the signal-to-noise ratio, and enhances the measurement accuracy of vibration speed by reducing the impact of return light.
Implementation Method 1
a light shielding element having an opening through which the laser light passes
Implementation Method 2
an optical modulator configured to modulate the laser light into reference light having a different frequency
Implementation Method 3
a light receiving element configured to receive object light generated by reflecting the laser light by an object to be measured and the reference light and output a light receiving signal
Implementation Method 4
a laser light source configured to emit laser light
Data Source
AI summary
A laser interferometer includes: a laser light source configured to emit laser light; a light shielding element having an opening through which the laser light passes; an optical modulator configured to modulate the laser light into reference light having a different frequency; and a light receiving element configured to receive object light generated by reflecting the laser light by an object to be measured and the reference light and output a light receiving signal. 0.10≤φpin≤10.0, in which φpin [mm] is a diameter of the opening.