3 Ways Imaging Colorimetry Can Improve Your FPD Inspection Process - - PowerPoint PPT Presentation

3 Ways Imaging Colorimetry Can Improve Your FPD Inspection Process

Presented By: Hubert Kostal, PhD November 4, 2014

Hubert Kostal, PhD

VP of Sales and Marketing

As Radiant Vision Systems’ VP of Sales and Marketing, Hubert Kostal

has helped global brands implement imaging technology in their production processes to improve display quality and optimize their supply chain. During his 7 years with the company, he has been a key driver in the transition of the technology from the lab to the production floor. Prior to joining Radiant, he held VP roles in both the semiconductor and LCD

• industries. He holds a PhD in Mathematics from The University of Texas, Austin, and

is the owner of 2 patents.

Outline

• Market drivers
• Problem statement
• Solution components
• Quality inspection
• Defect detection
• Mura detection
• Maximizing ROI

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3 Ways Imaging Colorimetry Improves FPD Inspection

Market forces: keeping up / gaining advantage

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Display Quality Cost = [End] Customer experience = Return / repair / replacement + Production costs + Lost future business

3 Ways Imaging Colorimetry Improves FPD Inspection

Human inspectors are not all that reliable!

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Human visual inspectors have poor performance on:

• Difficult to see defects
• Rarely seen defects

3 Ways Imaging Colorimetry Improves FPD Inspection

Escape (miss) rate Occurrence rate 0% 50% 100% Hard to see defects Easy to see defects Rarity effect

Imaging colorimeters

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…are CCD-based imaging systems (i.e., cameras) that are designed to replicate and quantify human perception of brightness and color

3 Ways Imaging Colorimetry Improves FPD Inspection

Image analysis for FPD inspection

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Quality Tests Defect Detection Mura Tests

Test Sequence Measurement Sequence Test Library Pass/ Fail Report

3 Ways Imaging Colorimetry Improves FPD Inspection

What failure modes to test for?

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A B C D E F G

H I … Z

Probability of

• ccurrence

Failure modes Individually important Important in aggregate Ignorable in aggregate Maximum allowed failure rate MUST TEST OPTIONAL*

* Assuming no “high cost” failure modes exist.

3 Ways Imaging Colorimetry Improves FPD Inspection

Role of test (image analysis) software

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Test control Test images Test results Measurement setup Test sequence & results

3 Ways Imaging Colorimetry Improves FPD Inspection

Example: Uniformity testing

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Measurement image Test analysis Color edge mura is a deviation in color at one or more

• f the edges.

The color edge mura is shown as a deviation from the

• verall color.

3 Ways Imaging Colorimetry Improves FPD Inspection

Example: Pixel-scale defects

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Particle defects are very small blemishes on the display. These can be the result of dust or defective pixels present in the display. Measurement image Test analysis

3 Ways Imaging Colorimetry Improves FPD Inspection

In this particular analysis, the display is segmented into regions to allow assessment of clustering.

Example: Mura detection

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Measurement image Test analysis Light leakage consists of different size bright areas near the edge of the display.

3 Ways Imaging Colorimetry Improves FPD Inspection

Individual mura are assigned JND (just noticeable difference) or similar values to assess their relative visibility and importance.

When does testing pay off? Assessing ROI

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Value of testing ($) Rate of occurrence of defects

3 Ways Imaging Colorimetry Improves FPD Inspection

0% ~0.5% ~10 -25% 100% Don’t test. Fix the process instead. End customer quality Production cost reduction Imaging colorimeter based testing

Quick summary

• Market drivers: Quality improvement and cost reduction
• Problem: Human inspectors are variable, and less and less capable.
• Solution components: Imaging colorimeters and analysis software
• Examples:
• 1. Quality inspection: Color and luminance uniformity
• 2. Defect detection: Pixel defects, line defects, and particles
• 3. Mura detection: General and specific mura
• Maximizing ROI: When is testing valuable?

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3 Ways Imaging Colorimetry Improves FPD Inspection

Thank You!

A recorded version of this presentation will be posted to our website within one week. You will receive a link to it via e-mail. If you have questions regarding this topic or presentation, please contact us at info@RadiantVS.com