Inclination Sensor with Optoelectronic Level and Fresnel Reflection

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Solution Overview

Problem

Existing inclination sensors are limited in accurately determining the direction and degree of inclination, are costly, and require large dimensions for effective operation, with issues in signal ambiguity due to small transmission differences and reflection/scatter phenomena, making automatic alignment and precise detection challenging.

Innovation Solution

The solution involves a micro-rough surface processing on the cover glass interface with the gas bubble, utilizing Fresnel reflection and scattered light generation for improved light distribution detection, combined with a light-absorbing surface and refractive index matching of glass and liquid to enhance signal-to-noise ratio and sensitivity, and using a chip substrate with strategically placed light receivers for accurate inclination measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If transillumination of dragonfly with light source and light receiver on opposite sides is used, then inclination can be detected, but the brightness differences are small and contours are blurred causing large detection uncertainties

Engineering Contradiction:
Improvedetection precisionVSAvoidsignal clarity
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

Instead of transmitting light through the bubble from one side to the other (transillumination), the invention places both light source and light receiver on the same side and detects reflected light. This inversion of the optical path eliminates the problems of small transmission differences and blurred contours, achieving clear binary signals for bubble position detection.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention replaces the mechanical/optical transillumination system with a reflection-based optical system. By using a light-reflecting liquid (mercury) and detecting reflected light patterns, the system achieves more reliable detection signals without the limitations of transmission through the bubble.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If total reflection principle is used with light source and light receiver on the same side, then binary centered/not-centered detection is achieved, but direction and degree of inclination cannot be determined

Engineering Contradiction:
Improvedetection simplicityVSAvoidinclination measurement capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The light receiver is divided into multiple segments or zones that can detect light from different angular directions. By analyzing which segments receive reflected light and the intensity distribution across segments, the system can determine not only if the bubble is centered but also the direction and degree of inclination.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from binary detection (centered/not-centered) to multi-dimensional measurement by using an array of light receivers or a position-sensitive detector. This allows detection of inclination in multiple directions and magnitudes, providing comprehensive orientation information.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If large distances between light emitter and detector are used for total reflection, then reflection effectiveness is improved, but sensor dimensions and cost increase

Engineering Contradiction:
Improvereflection effectivenessVSAvoidsensor size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The invention changes the optical parameters by using a light-reflecting liquid with high reflectivity (such as mercury) and optimizing the geometry of the bubble-liquid interface. This allows effective light reflection and detection at shorter distances, reducing sensor size while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses a composite arrangement of light-reflecting liquid, gas bubble, and transparent housing to create an optimized optical path. The combination of these materials and their specific optical properties enables effective reflection-based detection in a compact configuration.

Inventive Principle:
Principle #40Composite materials

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 reduces manufacturing costs, enhances detection sensitivity, and allows for precise determination of inclination direction and degree, enabling automatic alignment with reduced temperature influence and improved resolution.

Implementation Method 1

micro-rough surface processing on the cover glass interface with the gas bubble, utilizing Fresnel reflection and scattered light generation for improved light distribution detection

Methodology Applied
Scientific EffectScattered light generation: Scattering

Implementation Method 2

utilizing Fresnel reflection and scattered light generation for improved light distribution detection

Methodology Applied
Scientific EffectFresnel reflection: Fresnel Diffraction

Implementation Method 3

The housing is provided on the inside with a light-absorbing surface to suppress the disturbing scattered light from the bubble level walls

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 4

refractive index matching of glass and liquid to enhance signal-to-noise ratio and sensitivity

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2095071B1Inclination sensor with optoelectronic level
Publication Date: 2011.12.07 SARTORIUS WEIGHING TECH CO LTD
  • EP2095071B1 patent drawingFigure 1~2
  • EP2095071B1 patent drawingFigure 3
  • EP2095071B1 patent drawingFigure 4~5

AI summary

The invention relates to an inclination sensor having a level that has a liquid and a gas bubble under a covering glass in a housing. A light source is arranged above the covering glass. The invention is based on the object of providing an inclination sensor, which can be used to determine the direction and degree of an inclination with high accuracy and which is suitable for automatically aligning an apparatus provided with said inclination sensor. The object is achieved according to the invention by an arrangement in which at least two light receivers (2.4) are arranged above the covering glass (1.3) such that the light (L) that is emitted from the light source (2.3) and, in the case of a centered gas bubble (4), is scattered on the surface of the covering glass (1.3) coming in contact with the gas bubble (4) can be detected by means of said at least two light receivers (2.4). Different quantities of light can be detected by means of said light receivers (2.4) when the gas bubble (4) is not centered, and the light source (2.3) and the light receivers (2.4) are arranged on a chip substrate (2.1).