Optical Code Track Curved Elements Position Accuracy

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Solution Overview

Problem

Existing optical code tracks face errors due to diffraction phenomena and quasi-stochastic errors caused by rectangular code elements, leading to inaccuracies in determining object positions, especially when using few sensors and requiring minimal computational resources.

Innovation Solution

Implementing an optical code track with code elements that modulate light in a continuously varying manner, reducing diffraction effects and generating state signals with fewer errors, and using a mechanical support with varying code heights, point densities, or polarization efficiencies to achieve precise position determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If rectangular code elements are used to create digital absolute coding, then the position specification can be established with discrete code elements, but diffraction phenomena and quasi-stochastic errors occur leading to measurement inaccuracies

Engineering Contradiction:

Improveposition determination accuracyVSAvoiddiffraction errors and quasi-stochastic errors

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the geometric parameters of code elements from rectangular to curved (circular or elliptical) shapes. This parameter change fundamentally alters the light modulation pattern, transforming the state signal shape and eliminating the diffraction effects that cause measurement errors. The curved code elements produce state signals with smooth transitions that are less susceptible to diffraction phenomena.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies different local qualities to different parts of the code elements. The code elements have varying heights, curvatures, or densities in different regions, which creates locally optimized light modulation patterns. This local variation in code element properties helps eliminate systematic errors while maintaining the overall digital coding structure.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If multiple sensors are used to reduce non-systematic errors through averaging, then measurement accuracy improves, but device complexity and computational resources increase

Engineering Contradiction:

Improveposition determination accuracyVSAvoidnumber of sensors and computational resources

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent converts the harmful effect of using only a few sensors into a benefit by designing code elements that inherently reduce error sources. The curved code elements create state signals with reduced sensitivity to misalignment and diffraction, allowing accurate measurement even with minimal sensors. This eliminates the need for multiple sensors to achieve the same accuracy level.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If code elements with varying heights, point densities, or polarization efficiencies are implemented, then systematic errors are reduced and measurement accuracy improves, but manufacturing complexity increases

Engineering Contradiction:

Improvesystematic error reductionVSAvoidcode track production complexity

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent employs curved (circular or elliptical) code elements instead of rectangular ones. This curvature can be efficiently manufactured using standard coating and structuring techniques. The curved shapes naturally produce the desired varying light modulation patterns without requiring complex multi-layer structures or precise height variations, simplifying the manufacturing process while achieving the measurement accuracy goals.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 errors in position determination, enhancing the accuracy and availability of optical code tracks under various usage conditions while being cost-effective and compatible with existing coating techniques.

Implementation Method 1

The code elements modulate the light. Light passed by the light-transmissive rectangles is registered by a sensor along the track direction; light not passed by the optically opaque residual regions is not registered by the sensor.

Methodology Applied

Scientific EffectLight modulation:

Implementation Method 2

Light passed by the light-transmissive rectangles is registered by a sensor along the track direction; light not passed by the optically opaque residual regions is not registered by the sensor.

Methodology Applied

Scientific EffectOptical detection: Photoelectric Effect

Data Source

PatentUS9823097B2Method for determining absolute coding of an optical coding track

Publication Date: 2017.11.21 HEXAGON INNOVATION HUB GMBH

AI summary

The invention concerns a method for determining absolute coding represented by code elements of an optical code track, with illumination of the absolute coding with light, modulating of some of the illuminating light on code elements, determining of the absolute coding as modulated light and continuously varying modulation of the light on neighboring code elements.