Stabilizing Optical Axis for Non-Uniform Light Beams

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Solution Overview

Problem

Current methods fail to stably specify the optical axis and diameter of light beams with non-uniform intensity distributions, particularly in communication systems using collimated light from sources like VCSELs, leading to instability and potential communication issues due to axis deviation and diameter calculation errors.

Innovation Solution

A photodetection apparatus comprising an imaging element, processing unit, and display that calculates the optical axis and diameter of light beams by obtaining an approximate circle from the outer shape of light intensity distribution on a cross-section, using a specified ratio of total light intensity, thereby stabilizing axis determination and reducing the impact of non-uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the center of gravity method is used to specify optical axis for non-uniform light distribution, then axis position can be calculated, but the optical axis becomes unstable due to intensity distribution variations

Engineering Contradiction:
Improveoptical axis positionVSAvoidoptical axis stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the parameter used for axis determination from intensity-based (center of gravity) to geometric-based (outer shape of light distribution). By using the outer shape boundary and fitting an approximate circle, the method eliminates dependence on intensity distribution uniformity, thereby stabilizing optical axis measurement for non-uniform light sources like VCSELs

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional center of gravity calculation method with a geometric shape analysis method. Instead of calculating weighted positions based on intensity values, the new method detects the outer boundary shape of light distribution and fits a circle to determine the axis, substituting the mathematical approach to achieve stability

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

2Manufacturing precision

If conventional light specification methods are used for non-uniform distribution, then some cases are determined non-conforming, but communication is actually secured

Engineering Contradiction:
Improvelight beam specificationVSAvoidcommunication reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the specification parameters from intensity distribution-based (Gaussian fit) to geometry-based (outer shape, approximate circle). This allows non-uniform light sources to meet specifications while maintaining communication reliability, as the new parameters focus on geometric properties that remain stable despite intensity variations

Inventive Principle:
Principle #35Parameter changes

3Reliability

If mechanical tolerance is used to absorb axis deviation in multi-channel systems, then communication can be maintained, but specifications become too strict to realize

Engineering Contradiction:
Improvemulti-channel communicationVSAvoidconnector specification
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the axis determination parameter from intensity-based to geometry-based, which stabilizes the optical axis position and reduces deviation across channels. This eliminates the need for tight mechanical tolerances, making connector specifications more achievable while maintaining multi-channel communication reliability

Inventive Principle:
Principle #35Parameter changes

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 stable calculation of the optical axis and diameter of light beams with non-uniform intensity distributions, improving communication reliability by minimizing axis deviation and diameter errors, even in systems with multiple channels or non-perpendicular light output.

Implementation Method 1

A photodetection apparatus comprising an imaging element, processing unit, and display that calculates the optical axis and diameter of light beams by obtaining an approximate circle from the outer shape of light intensity distribution

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP3569975B1Light detection method, light detection device, and program
Publication Date: 2024.08.14 SONY GROUP CORP
  • EP3569975B1 patent drawingFigure 1~4
  • EP3569975B1 patent drawingFigure 5(a)~6(b)
  • EP3569975B1 patent drawingFigure 7(a)~8

AI summary

An optical axis or a diameter of light of even a light beam having a non-uniform intensity distribution is stably obtained. An outer shape of a range of a light intensity having a specified ratio with respect to a total light intensity on a cross-section of a light beam is obtained. An approximate circle is obtained from this outer shape. For example, the approximate circle is calculated by using the least-squares method. An optical axis and/or a diameter of light of the light beam is obtained on the basis of this approximate circle.