Anti-Reflective Coated Lubricant Sensor for Bearing Monitoring
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Solution Overview
Problem
Existing lubricant sensors in roller bearings face issues with high offset light output and reduced sensitivity due to reflections at the interfaces between the IR-permeable glass or crystal pane and the air, leading to inaccurate monitoring of lubricant quality, especially in difficult-to-access locations like wind turbines.
Innovation Solution
An anti-reflective coating is applied to the interior surface of the IR-transparent disk within the sensor housing to minimize reflections, allowing for improved detection of light scattered by the lubricant while maintaining the material properties of the pane and ensuring it remains in contact with the lubricant for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an IR-permeable pane made of scratch-resistant and heat-resistant glass or crystal is used to protect components against lubricant effects, then the protection against lubricant effects and mechanical durability is improved, but reflections occur at the pane interfaces causing high offset light output and reduced sensor sensitivity
Solution Approach 1:
The patent applies anti-reflective coatings to the IR-permeable pane surfaces, converting the harmful reflection effect into a beneficial low-reflection state. The anti-reflective coating minimizes reflections at the pane interfaces while maintaining the pane's protective function against lubricant effects and mechanical loads, thus resolving the contradiction between protection and measurement precision
Solution Approach 2:
The patent changes the optical parameters of the pane by applying anti-reflective coatings with specific refractive indices and thicknesses optimized for the infrared wavelength range. This parameter change reduces the reflection coefficient at the pane interfaces, allowing the sensor to maintain high sensitivity while the pane continues to provide mechanical and chemical protection
2Strength
If the pane has a comparatively high refractive index to provide effective protection, then the mechanical strength and protection are improved, but reflections occur on the inner boundary surface leading to high offset light output
Solution Approach 1:
The anti-reflective coating converts the harmful reflection caused by the high refractive index into a beneficial low-reflection interface. The coating's refractive index is intermediate between air and the high-index pane material, reducing the reflection coefficient and minimizing offset light output while the pane maintains its mechanical strength
Solution Approach 2:
The anti-reflective coating acts as an intermediary layer between air and the high-refractive-index pane material. This intermediate layer with optimized refractive index reduces the optical impedance mismatch, minimizing reflections at the interface while allowing the high-strength pane to maintain its protective function
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 anti-reflective coating reduces offset light output and enhances sensor sensitivity, enabling more precise monitoring of lubricant quality by minimizing reflections and ensuring accurate detection of light scattered by the lubricant, thus improving the resolution and reliability of the sensor.
Implementation Method 1
an anti-reflective coating is applied to the interior surface of the IR-transparent disk within the sensor housing to minimize reflections
Implementation Method 2
Such a sensor usually comprises a number of LEDs as an infrared (IR) light source
Implementation Method 3
a sensor can be installed in a roller bearing, which is designed to measure the scattering of infrared light of different wavelengths by the lubricant
Implementation Method 4
the pane and the air in the interior of the sensor, reflections occur on the inner boundary surface of the pane
Implementation Method 5
light scattered by the lubricant, which enters the sensor through the pane
Data Source
Figure 1~2
AI summary
The invention relates to a lubricant sensor (1) comprising a housing (2), an IR light source (10) arranged in the housing (2), a first IR detector (6) arranged in the housing (2), and a disk (20) which is inserted into an opening of the housing, said disk (20) being permeable in the spectral range of the IR light source (10). According to the invention, the disk (20) has an anti-reflective coating at least for the spectral range of the IR light source (10) towards the interior (18) of the housing. Furthermore, a rolling bearing (40) is provided with such a lubricant sensor (1).