APPLICATIONS OF HIGH RESOLUTION MEASUREMENT

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1 APPLICATIONS OF HIGH RESOLUTION MEASUREMENT Doug Kreysar, Chief Solutions Officer November 4,

2 AGENDA Welcome to Radiant Vision Systems Trends in Display Technologies Automated Visual Inspection (AVI) High-Resolution Measurement Solutions Detailed detection of pixel, line, and particle defects Mura detection in high definition displays Pixel luminance measurements / OLED screen correction Visual surface inspection Live Demonstration 2

3 QUANTIFYING HUMAN VISUAL PERCEPTION Radiant Vision Systems imaging hardware and software replicate and quantify human perception of brightness, color and scatter 3

4 A Konica Minolta Company 4

5 RADIANT TIMELINE 1992 Company Founded as Radiant Imaging Focus on Imaging Colorimetry and test systems for lighting and display applications Introduce ProMetric F-Series Imaging Colorimeters Focus on Imaging Colorimetry for high volume production test. Q Introduce ProMetric I-Series Q Introduce ProMetric Y-Series Q Acquired by Konica Minolta Introduce first Imaging Colorimeter and Source Imaging Goniometer for 2D and 3D colorimetry Q Merge Radiant Imaging with Zemax Development Q Introduce TrueTest Software Q Introduce ProMetric G Series Q Divest Zemax Q Launch Radiant Vision Systems 5

6 Trends in Display Technologies 6

7 FOUR TECHNOLOGY INFLECTIONS Per Max McDaniel, Applied Materials, at SID Display Week

8 MICRO DISPLAYS POISED TO GO MAINSTREAM AR + VR revenue will reach $150 billion by 2020 Est $40B in AR hardware, $7B in VR hardware Statista By 2018, unit sales of VR HMDs are forecast to reach 39 million units 8

9 GROWING NEEDS FOR: Inspection of large displays while meeting required takt times Improved accuracy over human inspection on increasingly pixel-dense displays Pixel level accuracy Detection of dead, stuck, & nonuniform pixels OLED correction 9

10 Automated Visual Inspection (AVI) 10

11 AUTOMATED VISUAL INSPECTION Automated Visual Inspection (AVI) is a proven technology for testing and grading FPDs AVI replaces Human Visual Inspection AVI system consists of an Imaging Colorimeter and sophisticated software New defect and mura (blemish) types continually emerge due to: larger displays, smaller displays higher resolution new display technologies Test systems and algorithms must evolve quickly to keep up 11

12 FASTER, HIGHER-RESOLUTION MEASUREMENT SYSTEMS ProMetric I Colorimeters 2, 8, 16 and 29 MP Interline CCD High Dynamic Range mode Ideal for production - when speed matters ProMetric G Colorimeters 2 and 6 MP Full-frame CCD Ideal for high-accuracy R&D, lighting, low-light testing, mura evaluation ProMetric Y Photometers 2, 16 and 29 MP Interline CCD Small form factor Optimized for displays, keyboards and Automated Surface Test 12

13 ANALYSIS SOFTWARE SUITE 3 rd party software Grading Engine 13

14 FOUR STEPS OF AVI Measurement Image 1 2 Local Contrast Image 3 JND: Standard Spatial Observer or SEMU 4 Weighting Mura Defects Observer - + Luminance Local Contrast Noticeability Noticeability Analysis on the unprocessed Measurement Image Displays often have small gradients (mura) on-top of a large gradual slope Analysis after largescale gradients are filtered from the Measurement Image Analysis after the Local Contrast Image is processed for JND Analysis with Weighting & Filtering of different types of mura defects 14

15 FILTERING & WEIGHTING DEFECTS + - Filter mura on local contrast value Distinction between bright and dark mura Filter on mura shape (circularity / line shape) Cx, Cy Filter on mura surface area Filter mura on position in the image Filter on color 15

16 High-Resolution Measurement Solutions 16

17 DETAILED DETECTION OF PIXEL, LINE, AND PARTICLE DEFECTS 17

18 DETAILED DETECTION OF PIXEL, LINE, AND PARTICLE DEFECTS MANUFACTURERS FACE NEW INSPECTION CHALLENGES As display resolution has gone from Full HD to 4K to 8K, consistent detection of pixel and particle displays by human inspectors has become difficult. Automated alternatives often fail to meet required takt times in production environments. 18

19 DETAILED DETECTION OF PIXEL, LINE, AND PARTICLE DEFECTS DEFECT DETECTION WITH HIGH RESOLUTION AVI High resolution measurement makes it possible to detect every pixel and line defect. Large displays and multi-channel configurations are possible. Acceptable takt times are achieved. Sophisticated analysis makes it possible to screen and grade displays so that displays below a quality threshold do not escape to customers. 19

20 DETAILED DETECTION OF PIXEL, LINE, AND PARTICLE DEFECTS AVI TEST FOR PARTICLE DEFECTS Particle defects are very small blemishes, the result of dust or defective pixels in the display Particle defects can cause display to have dark or bright spots Final Analysis Test Image 20

21 MURA DETECTION IN HIGH DEFINITION DISPLAYS 21

22 MURA DETECTION IN HIGH DEFINITION DISPLAYS MURA COMES IN MANY FORMS Mura is a Japanese word for blemish Many types with different causes Line, spot, polarizer deformation, corner-light, edge-light New display technologies continually introduce new mura types Difficult to detect, particularly on large, high-resolution displays Subtle, low-contrast defects of irregular shape and size Human inspection may be subjective, variable Sophisticated image analysis algorithms make it possible to evaluate mura in displays: accurately objectively repeatably with high correlation to human inspection 22

23 MURA DETECTION IN HIGH DEFINITION DISPLAYS BENEFITS OF HIGH RESOLUTION MURA DETECTION The higher the resolution, the more mura types that can be detected With more mura types, AVI can be used to: Improve Quality (Pareto) Grade/ Bin Displays Improve yield with Repair Decisions 23

24 MURA DETECTION IN HIGH DEFINITION DISPLAYS PARETO OF PROCESS IMPROVEMENTS AVI can consistently detect flaws or defects introduced by prior manufacturing and handling steps. Over time, trends and patterns in the image analyses can be used to adjust processes to remedy recurring quality issues. Defect Frequency Pareto of DUT Defects 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Cumulative Defect % 24

25 MURA DETECTION IN HIGH DEFINITION DISPLAYS AVI-BASED GRADING Production test users wish to make more sophisticated grading distinctions than simply Pass / Fail Grading segregates displays into quality levels (A, B, C, F) Deploying grading can help manufacturers: Identify repairable product Improve yield Assign appropriate product to correct purpose Grading can be based on: Luminance level or range Contrast Pixel defects Line defects Uniformity across the display area 25

26 MURA DETECTION IN HIGH DEFINITION DISPLAYS REPAIR DECISIONS The ability to identify the type and grade of mura can enable decisions as to whether or not a display can be reworked or repaired. 26

27 PIXEL LUMINANCE MEASUREMENTS and OLED CORRECTION 27

28 PIXEL LUMINANCE MEASUREMENTS & OLED CORRECTION PIXEL LUMINANCE MEASUREMENTS Pixel defects detract from the end user experience: Dead pixels Stuck pixels Non-uniform pixels Highly noticeable in micro displays May be correctable 28

29 PIXEL LUMINANCE MEASUREMENTS & OLED CORRECTION PIXEL LEVEL CORRECTION OF OLEDS OLED displays work differently than backlit LCD displays Each sub-pixel is an independent light emitter which will behave and age differently. LCD non-uniformity tends to be large in scale, while OLED presents random mura - each pixel being slightly different than its neighbor. Increasing yields is critical to adoption of OLEDs. Correcting each pixel emitter is an effective way to do this. LCD OLED 29

30 PIXEL-BY-PIXEL CORRECTION The most accurate way to remove the pixel non-uniformities is at the pixel-by-pixel level. To measure each display pixel, we need many CCD measurement pixels (e.g. 10x10). To do this, we measure a portion of the pixels of the display, using a spaced-pixel pattern, turning on certain pixels at a time, and proceeding through each pattern until all pixels are measured. The pixel color and luminance values can be corrected to match target values using a correction matrix calculated and applied to the input RGB signal. Spaced Cols 3, Spaced Rows 3, first pattern Spaced Cols 3, Spaced Rows 3, second pattern 30

31 PIXEL LUMINANCE MEASUREMENTS & OLED CORRECTION PIXEL LUMINANCE MEASUREMENT The spaced pixel technology can be applied to simply measure the luminance and color of all pixels on a display. Defective pixels can be pinpointed by coordinate and the output can be fed into a repair machine to fix the specific defective pixels. This operation is fully integrated into TrueTest. 31

32 PIXEL LUMINANCE MEASUREMENTS & OLED CORRECTION SOLUTION COMPONENTS Radiant software, coupled with a ProMetric PM-I16 or PM-I29 Imaging Colorimeter, supports brightness correction on an individual pixel basis for an entire OLED display. The results can be programmed into flash memory, stored as image files, or look up tables can be created. The Radiant platform offers flexibility plus integration. 32

33 VISUAL SURFACE INSPECTION 33

34 VISUAL SURFACE INSPECTION DETECTION OF SURFACE DEFECTS Beyond lighted displays, Imaging Colorimeters may also be applied to the detection of defects on non-lighted surfaces. Using contrast detection, spatial measurement, mura detection, pattern matching, and optical character recognition (OCR), the following cosmetic defects may be detected and quantified. Problem Surface attributes Surface Defects Features Gaps Patterns Examples Surface Color Finish uniformity Scratches, dents, dings Surface particles, foreign material Logo defects Connector, camera or button existence / positioning Key position / cosmetics Fit of component surfaces. Seams Text (Part #, SN, SKU) readability and correctness via OCR Label positioning Label correctness via pattern matching and/or OCR 34

35 VISUAL SURFACE INSPECTION SURFACE DEFECTS: SCRATCH & DENT Scratches are identified based on their contrast. The values shown are contrast ratios relative to a background level. A dent s length and width can be measured and used to determine whether a product passes or fails. 35

36 CONCLUSIONS High resolution measurement enables these operations: Detailed detection of pixel, line, and particle defects Mura detection in high definition displays Pixel luminance measurements / OLED screen correction Visual surface inspection Pixel Correction and mura detection have the potential to significantly increase the quality and yield of LCD and OLED production lines. Radiant Vision Systems has significant experience in integrating high resolution measurement solutions that work for customers in their specific applications. 36

37 THANK YOU! Contact: 37