Fiber Block Parallelism Adjustment Using Contact Sensor Feedback

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Solution Overview

Problem

Existing methods for adjusting the parallelism of a block of fibers with a semiconductor chip or wafer on an XY table are imprecise, expensive, and complex, particularly due to challenges in visualizing transparent materials and achieving sufficient precision with cameras.

Innovation Solution

A method utilizing a sensor integral with the XY table and a manipulator arm to adjust the parallelism by moving the block relative to the XY table in X, Y, and Z directions, using contact sensors to measure distances and deformations, allowing for precise orientation adjustments without the need for high-cost optical sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If cameras are used to visualize the orientation of the block of fibers, then the parallelism adjustment can be performed, but the precision is insufficient and the cost is high

Engineering Contradiction:
Improveprecision of parallelism adjustmentVSAvoidcomplexity of camera system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the optical camera-based measurement system with a mechanical contact sensor system. A probe equipped with a contact sensor (such as a capacitive, inductive, or optical sensor that detects physical contact) mechanically touches the lower face of the block of fibers at multiple points to directly measure the position and orientation, substituting the complex optical visualization system with a simpler mechanical measurement approach that provides sufficient precision for parallelism adjustment.

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

2Measurement precision

If multiple cameras with high resolution are used to achieve sufficient precision, then the measurement accuracy improves, but the cost increases significantly

Engineering Contradiction:
Improveprecision of orientation measurementVSAvoidcost of camera system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive high-resolution camera systems with a mechanical probe equipped with contact sensors. The probe physically contacts the block of fibers at multiple points to measure positions, using mechanical measurement principles rather than optical imaging. This substitution dramatically reduces system cost while maintaining the precision needed for parallelism adjustment, as the mechanical contact method directly measures positions without requiring complex optical processing.

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

3Difficulty of detecting and measuring

If cameras are used to observe transparent materials, then visualization is attempted, but refraction and reflection cause blurred outlines and limit resolution

Engineering Contradiction:
Improvedifficulty of observing transparent materialsVSAvoidresolution of camera observation
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent replaces optical observation methods with mechanical contact measurement. Instead of using cameras that struggle with transparent materials due to refraction and reflection, a physical probe with contact sensors directly touches and measures the block of fibers. This mechanical approach completely avoids optical interaction with transparent materials, eliminating refraction and reflection problems and providing clear, precise measurements of the block's orientation and position.

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

4Ease of operation

If the block of fibers is manually adjusted until faces are substantially parallel, then the adjustment can be performed, but the precision is insufficient for the required ±2.5 μm tolerance

Engineering Contradiction:
Improveease of parallelism adjustmentVSAvoidprecision of fiber positioning
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent implements a feedback-based measurement and adjustment system. The probe measures the actual positions of multiple points on the block of fibers, calculates the current orientation and parallelism deviation, and provides feedback information that guides the adjustment process. This closed-loop feedback mechanism enables precise adjustment to within the required ±2.5 μm tolerance, far exceeding what manual visual adjustment can achieve, while still maintaining ease of operation through automated measurement and calculation.

Inventive Principle:
Principle #23Feedback

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 provides a more precise, cost-effective, and simpler method for aligning the block of fibers, achieving the required parallelism with high accuracy and reducing implementation complexity, especially when dealing with transparent materials.

Implementation Method 1

the sensor is a contact sensor, step b) comprising, for each point, moving the block in Z from a reference position to a position of contact with the sensor, and determining the distance in Z traveled by the block between the reference and contacting positions

Methodology Applied
Scientific EffectContact sensing:

Implementation Method 2

the sensor comprises a deformable element in Z, a device for measuring the deformation in Z, and a contact element mounted on the deformable element, step b) comprising, for each point, moving the block in Z until the deformable element is deformed in Z, and determining the distance in Z traveled by the block between the reference position and a contacting position of the point and of the contact element

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 3

the device for measuring the deformation is a strain gauge placed on the lamella

Methodology Applied
Scientific EffectStrain gauge measurement:

Data Source

PatentEP3373053B1Method for adjusting the parallelism of a block of fibres with a surface of a die
Publication Date: 2022.02.23 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3373053B1 patent drawingFigure 1~2C
  • EP3373053B1 patent drawingFigure 3A~4B

AI summary

The invention relates to a method for adjusting the parallelism of a face (17) of a block (13) of optical fibers (15) with a face of a semiconductor chip or wafer placed on an XY table (5), comprising the following steps: a) providing a sensor (9) fixed to the XY table and a manipulator arm (7) carrying the block, said face (17) being turned towards the XY table; b) for each of three non-aligned points of the face (17) of the block (13), performing a displacement relative to each other of the XY table (5) and the block (13) in the X and/or Y directions to put the sensor (9) opposite the point, and evaluate, with the sensor (9), the distance in Z between the point and the sensor; and c) modifying the orientation of the block (13) by means of the manipulator arm (7) to ensure the desired parallelism.