Multi-Beam Optical Tilt Sensing Without Distance Calibration
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Solution Overview
Problem
Existing optical tilt sensors require calibration to determine the tilt and displacement of flat reflective surfaces, and they are less accurate when the distance from the sensor to the surface is unknown.
Innovation Solution
An optical tilt sensor that emits at least three beams of light with known orientations relative to a pivot axis, allowing for the detection of intensity distributions without calibration, using an image sensor to determine the tilt angle based on the spatial relationships and orientations of the emission paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional optical tilt sensors use single beam reflection detection, then the device structure is simple, but calibration is required and measurement accuracy deteriorates when distance is unknown
Solution Approach 1:
The optical emitter is divided into multiple emission points (at least three) that emit light beams along different emission paths. Each emission point has a known spatial relationship to the others, creating multiple reflected beams that are detected by the image sensor. This segmentation allows the system to calculate tilt angles without calibration by comparing the spatial relationships between multiple reflection points.
Solution Approach 2:
The invention transitions from detecting a single reflection point to detecting multiple reflection points in three-dimensional space. By emitting at least three beams along different paths with known orientations relative to the sensor area, the system adds spatial dimensionality to the measurement, enabling distance-independent tilt measurement through geometric relationships.
2Measurement precision
If multiple photodetectors or multi-area sensors are used to detect reflected light, then tilt measurement capability is improved, but calibration is still required before measurement
Solution Approach 1:
The system performs preliminary action by establishing known spatial relationships between multiple emission points and their corresponding emission directions before actual measurement. The orientations of emission paths relative to the sensor area are predetermined and known, allowing the system to directly calculate tilt angles from geometric relationships without requiring field calibration.
Solution Approach 2:
The optical tilt sensor performs self-service by using its own internal geometric structure (known emission point positions and emission directions) to enable measurements. The system determines tilt angles through self-referential geometric calculations based on the known spatial relationships between multiple emission paths and their reflections, eliminating the need for external calibration procedures.
3Measurement precision
If diffractive optical elements are used to diffract reflected light, then tilt measurement can be performed, but the system requires calibration and has complex optical components
Solution Approach 1:
The invention extracts the essential measurement function from complex optical elements like diffractive components. By using multiple direct reflection paths with known geometric relationships, the system achieves tilt measurement without requiring diffractive optical elements, simplifying the overall device structure while maintaining measurement capability.
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 measurement of tilt angles without calibration, even when the distance from the sensor to the surface is unknown, with higher accuracy for measuring changes in tilt angles.
Implementation Method 1
measuring the tilt and/or displacement of a flat reflective surface which rely upon the reflection of a beam of light from the flat reflective surface and the detection of the reflected beam of light
Data Source
AI summary
An optical tilt measurement apparatus includes an optical tilt sensor for use in sensing a tilt angle of a flat reflective surface around a pivot axis. The optical tilt sensor includes an optical emitter arrangement for emitting at least three beams of light so that each emitted beam of light is incident on, and reflected from, the flat reflective surface to form a corresponding reflected beam of light. The optical tilt sensor also includes an image sensor having a sensor area for detecting an intensity distribution of each of the reflected beams of light and outputting one or more signals representative of the detected intensity distribution of each of the reflected beams of light. The at least three emitted beams of light are emitted along at least three corresponding different emission paths. Each emission path extends from a corresponding emission point along a different corresponding emission direction.