LED Optical Alignment Using Dual-Side Imaging Offset Compensation

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Solution Overview

Problem

Current methods for aligning LEDs during assembly, which rely on geometric center alignment, often result in misalignment due to offsets between the light-emitting surface and electrical connection contacts, leading to poor assembly reliability and potential soldering quality issues.

Innovation Solution

A method involving optical capture of images from both sides of the LED component using cameras to determine and compensate for the spatial offset between the light-emitting chip and electrical connections, ensuring precise alignment of the light-emitting surface on the component carrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If geometric center alignment is used for LED assembly, then assembly process is simple, but alignment precision deteriorates due to offset between geometric center and light-emitting surface

Engineering Contradiction:
Improveassembly process simplicityVSAvoidalignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent performs optical measurement of the LED component's light-emitting surface position before assembly. The measurement system captures images of the LED component and calculates the offset between the geometric center and light-emitting surface center in advance. This preliminary measurement data is then used to compensate for the offset during the assembly process, ensuring precise alignment without requiring complex real-time adjustments.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If optical measurement of light-emitting surface is performed, then alignment precision is improved, but device complexity increases due to additional measurement systems

Engineering Contradiction:
Improvealignment precisionVSAvoidmeasurement system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent integrates the optical measurement function into the existing automatic placement machine. The measurement system uses the same image capture devices and processing units that are already part of the placement machine's positioning system. By making the measurement system multi-functional (serving both measurement and assembly guidance purposes), the patent avoids adding separate complex measurement equipment, thus reducing overall device complexity while maintaining high alignment precision.

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

3Reliability

If offset compensation is implemented, then assembly reliability is improved, but measurement precision requirements increase

Engineering Contradiction:
Improveassembly reliabilityVSAvoidoffset measurement precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the measured offset between the geometric center and light-emitting surface center is used to adjust the placement position. The measurement system captures images of the LED component, calculates the actual offset, and feeds this information back to the placement system. The placement system then compensates for the offset by adjusting the placement coordinates, ensuring that the light-emitting surface aligns precisely with the target position on the component carrier. This feedback loop improves assembly reliability by accounting for manufacturing variations in LED components.

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 allows for precise optical positioning of LEDs, improving assembly reliability by accurately accounting for the spatial offset between the light-emitting surface and electrical connections, thereby enhancing the quality of the assembly process.

Implementation Method 1

optically capturing a first image of a first side of the component using a first camera, optically capturing a second image of a second side of the component using a second camera

Methodology Applied
Scientific EffectOptical imaging: Photography

Data Source

PatentEP2908614B9Optical measuring of a component with structural features on opposing sides
Publication Date: 2017.11.08 ASM ASSEMBLY SYST GMBH & CO
  • EP2908614B9 patent drawingFigure 1a~1c
  • EP2908614B9 patent drawingFigure 1d~1f
  • EP2908614B9 patent drawingFigure 1g

AI summary

A method for mounting an electronic component (180) onto a component carrier (175) is described. The method comprises (a) optically capturing a first image of a first side of the component (180), on which a first structural feature (185) of the component (180) is recognizable, using a first camera (120), (b) optically capturing a second image of a second side of the component (180), on which a second structural feature (186) of the component (180) is recognizable, using a second camera (160), wherein the first side and the second side are opposite each other and wherein the second structural feature (186) is configured to be connected at a predetermined position on the component carrier (175).(c) orienting the electronic component (180) such that the center of the first structural feature (185) is aligned with a desired position relative to the component carrier (175), wherein the second structural feature (186) may be offset accordingly from the predetermined position, and (d) mounting the electronic component (180) onto the component carrier (175), wherein the center of the first structural feature (185) is aligned relative to the component carrier (175), and the second structural feature (186) is offset from the predetermined position. Furthermore, a method for verifying the functionality of an optoelectronic component prior to mounting it on a component carrier and a placement machine for mounting an optically measured electronic component are described.