Orthogonal Pixel Rows for High-Speed Fringe Attitude Detection

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Solution Overview

Problem

Conventional image sensors for detecting interference fringes require complex optical systems and are not capable of high-speed detection, limiting their functionality and accuracy in attitude detection of irradiated bodies.

Innovation Solution

An image sensor with two orthogonal rows of pixels that capture fragmental images of linear fringes, allowing for rapid detection of fringe changes and attitude determination without the need for a complex optical configuration, utilizing signal processing to connect bright or dark parts of orthogonal fringes and estimate fringe images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional area image sensor is used to detect interference fringes, then the sensor can capture two-dimensional fringe images and detect the attitude of the reflecting surface, but the detection speed is far slower than that of a PSD

Engineering Contradiction:
Improveattitude detection capabilityVSAvoiddetection speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent divides the light receiving plane into two separate straight rows of pixels oriented in orthogonal directions. This segmentation allows each row to independently detect linear fringes in its respective direction, enabling high-speed detection while maintaining the capability to capture two-dimensional fringe information through coordinate transformation and synthesis of results from both rows.

Inventive Principle:
Principle #1Segmentation

2Speed

If a line image sensor is used to improve detection speed, then the response can be improved with detection speed about 1000 times higher than CCD, but a complicated optical system must be set up on the optical path to split and reorient the interference fringes

Engineering Contradiction:
Improvedetection speedVSAvoidoptical system complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent introduces a second dimension by adding two orthogonal rows of pixels instead of using a single row. This dimensional expansion allows the sensor to directly capture linear fringes in both horizontal and vertical directions simultaneously, eliminating the need for complex optical components to split and reorient fringes while maintaining high detection speed.

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

3Speed

If a PSD is used for high-speed detection, then the detection speed is significantly higher than area image sensors, but the PSD detects only the centroid value of light amount and is not suitable for detecting fringes

Engineering Contradiction:
Improvedetection speedVSAvoidfringe detection capability
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent creates multiple copies of detection capability by using two separate rows of pixels instead of a single centroid-detecting element. Each row independently captures linear fringe patterns in its orientation, preserving fringe detection capability while achieving high-speed performance similar to PSD through the linear array architecture.

Inventive Principle:
Principle #26Copying

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 high-resolution, high-stability, and fast-response attitude detection with a simpler optical structure, achieving detection speeds several orders of magnitude higher than conventional area image sensors and allowing for three-dimensional measurement applications.

Implementation Method 1

The beam splitter recombines the beams reflected from the reference mirror and the irradiated body to cause interference. The resulting interference fringes are captured by an image sensor.

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

The reference beam hits a reference mirror, and the measurement beam hits a reflecting surface formed on the irradiated body. The beam splitter recombines the beams reflected from the reference mirror and the irradiated body

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

two straight rows of pixels disposed at right angles to each other... each pixel can detect the amount of light received

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2613121B1Image sensor, attitude detector, contact probe, and multi-sensing probe
Publication Date: 2022.03.23 MITUTOYO CORP
  • EP2613121B1 patent drawingFigure 1A~2B
  • EP2613121B1 patent drawingFigure 3A~4
  • EP2613121B1 patent drawingFigure 5~6

AI summary

An image sensor for fringe images of interference fringes and the like in which the optical system has a simpler configuration than that of the conventional line image sensor, and faster detection becomes possible includes a light receiving plane on which two or more straight rows of pixels (62) are disposed, and captures images of regular fringes generated from light reflected from an irradiated body (14,66) in accordance with the amount of light received by each pixel; among the rows of pixels, at least two rows of pixels are disposed at right angles to each other, and acquires images of linear fringes crossing almost at right angles in two directions among the fringe projected onto the light receiving plane.