Multiple-Beam Triangulation Range Finder Tilt Robustness

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Solution Overview

Problem

Existing time-of-flight range finders are inadequate for short distances and can be complex and expensive, making them unsuitable for applications requiring precise distance measurement at close ranges.

Innovation Solution

A multiple-beam triangulation-based range finder that emits multiple light beams from different locations, intersecting at a specific distance, and uses a quadrant detector to produce a trigger signal based on the distance from the target, allowing for precise detection of when the target is within or beyond a specific threshold distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If time-of-flight range finders are used for distance measurement, then measurement capability is provided, but the system becomes complex and expensive, especially for short distances

Engineering Contradiction:
Improvedistance measurement capabilityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex time-of-flight measurement systems with a simpler triangulation-based optical system. Instead of measuring the time for light to travel to and from the target, the system uses geometric triangulation with a light source, beam splitter, and position-sensitive detector to determine distance based on the position of reflected light, eliminating the need for complex timing electronics while achieving accurate short-distance measurement.

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

Solution Approach 2:

The patent employs commercially available, inexpensive components such as LED light sources, standard beam splitters, and position-sensitive detectors to create a cost-effective range finder. This approach replaces expensive specialized time-of-flight components with readily available optical elements, significantly reducing system cost while maintaining measurement functionality.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If time-of-flight range finders are used, then distance measurement is achieved, but the system is inadequate for short distances of 10 meters or less

Engineering Contradiction:
Improveshort distance measurement accuracyVSAvoidmeasurement reliability at short range
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the fundamental measurement parameter from time-of-flight to angular position. By measuring the angular deviation of reflected light using a position-sensitive detector and converting this to distance through triangulation geometry, the system achieves high precision at short distances where time-of-flight methods fail due to insufficient time resolution.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from a temporal measurement approach (time-of-flight) to a spatial measurement approach (angular position on a detector). This dimensional shift from time domain to space domain enables accurate measurement at short distances by exploiting the angular separation of light paths rather than timing light travel.

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

3Reliability

If multiple light beams are emitted from different locations, then robustness against target tilt and non-flat surfaces is improved, but device complexity increases

Engineering Contradiction:
Improverobustness against target tiltVSAvoidmultiple beam configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the optical system into multiple independent light-emitting locations, each projecting a separate beam onto the target. By using multiple beams from different positions, the system can detect and compensate for target tilt and surface irregularities, as each beam provides independent measurement data that can be combined to achieve robust distance measurement despite target orientation variations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent makes the optical system multi-functional by using the same basic components (light source, beam splitter, position-sensitive detector) to perform both distance measurement and tilt compensation. The multiple beams serve dual purposes: providing redundant measurement paths for distance determination and enabling detection of target orientation, thereby achieving multiple functions without proportionally increasing system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 system provides robustness against target tilt and non-flat surfaces, enabling accurate and efficient distance measurement and triggering events at short distances, improving upon the limitations of existing range finders.

Implementation Method 1

a quadrant detector coupled to the housing, centered with respect to the longitudinal axis, and configured to receive light from the first and second light beams that is reflected from a target

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3271749B1Multiple-beam triangulation-based range finder and method
Publication Date: 2019.09.04 RAYTHEON CO
  • EP3271749B1 patent drawingFigure 1~4
  • EP3271749B1 patent drawingFigure 5~8
  • EP3271749B1 patent drawingFigure 9

AI summary

A multiple-beam triangulation-based range finder can direct multiple beams onto a sample from different orientations. The range finder can use a quadrant detector to detect light from the multiple beams that is reflected from the sample. The range finder generates a trigger signal when the target is a specified distance from the range finder. In some examples, two or more of the multiple beams are directed onto the sample simultaneously, where the beams are modulated at different frequencies and the signals from the quadrant detector are analyzed at the respective frequencies. In some examples, two or more of the multiple beams are directed onto the sample in succession, where the signals from the quadrant detector are analyzed in respective time windows. Using multiple beams with the quadrant detector can increase robustness against relative tilt of the sample with respect to the range finder.