Changhee Lee School of Electrical Engineering and Computer Science Seoul National Univ. chlee7@snu.ac.kr 0 OLED Performance 1
AMOLED 불량원인 양중환, 윤종근, 한국정보디스플레이학회지, 8 (5), 11 (2007) 2 AMOLED 불량별발생원인 양중환, 윤종근, 한국정보디스플레이학회지, 8 (5), 11 (2007) 3
AMOLED 불량 : LTPS 기판 양중환, 윤종근, 한국정보디스플레이학회지, 8 (5), 11 (2007) 4 LTPS 기판의 Photo 공정의불량 양중환, 윤종근, 한국정보디스플레이학회지, 8 (5), 11 (2007) 5
TFT 특성불량 누설전류증가에의한휘점 (bright spot) Vth shift 에의한암점 (dark spot) 양중환, 윤종근, 한국정보디스플레이학회지, 8 (5), 11 (2007) OLED 공정에서의불량 양중환, 윤종근, 한국정보디스플레이학회지, 8 (5), 11 (2007)
OLED 공정에서의불량의예 마스크긁힘 마스크정렬불량에의한국부적색변질 Cathode metal splash Cathode defect 및이물에의한화소부축소 양중환, 윤종근, 한국정보디스플레이학회지, 8 (5), 11 (2007) OLED 공정에서의불량의예 양중환, 윤종근, 한국정보디스플레이학회지, 8 (5), 11 (2007) 9
Display Metrology Measure useful parameters: display vision Make it reproducible (for millions of years, if necessary) Make sure the metrics apply to all types Standardize! IEC, ISO, VESA, JEITA, KS, etc. Metrics for emissive displays Luminance, uniformity Dynamic response (Switching, warm-up, flicker) Contrast ratio (plain field / window) Specular reflections / White chromaticity, colour reproduction / gamut Resolution (analog / digital) Power consumption Additional for transmissive displays Viewing direction / angle range Gray scale inversion Cross-talk 10 Radiometry and Photometry Radiometry Photometry Watt W/nm 1/60 of the luminous intensity per square centimeter of a blackbody radiating at the temperature of 2,046 degrees Kelvin Φ υ = Photopic vision eye sensitivity 683 lm Luminous flux I υ W Φ e V W/nm = dφ dω = 683 lm W υ Luminous intensity (Candela = lm/sr SI unit) ( λ) dλ Wavelength (nm) Luminous efficiency: power into actuation of vision (lm/w) I e V ( λ) dλ 11
CIE 1931 Color Matching Functions CIE 1931 Color Matching Functions (2 deg. Observe Light (arb. unit) 1.5 1.0 0.5 z y x 0.0 400 500 600 700 12 Wavelength (nm) Chromaticity Coordinates & Color Temperature X = K Y = K Z = K 780 380 780 380 780 380 S( λ) xdλ S( λ) ydλ S( λ) ydλ X x = X + Y + Z x + y + z =1 K = 683 lm/w Y y = X + Y + Z A black body radiator (Planckian Source) glows with a color that is solely dependent on its temperature (in K). Standard source D 65 (daylight, 6500 K) (x,y) = (0.312, 0.329) E = Equal Energy point: (0.333, 0.333) 13
Measurement system setup > 500 pixels e.g. O 4cm diaphragm θ accept < 5 0 e.g 50 cm Device under test Light measuring device 14 Standardized measurement equipment Specular reflection θ a Light source Lamp Incident light θ in Diffuser Reflected light θ out θ b Specular Glare Diffuse Display surface Luminance meter * Light source determines measurement result 15 Standard illuminants CIE A (2856 K) CIE B (abandoned) CIE C (6750 K) CIE D65 (6500 K)
Standardized measurement equipment Apparently, anyone is free to choose the method that suits the display best. This makes it very difficult to make a fair comparison. Source: Edward F. Kelley, NIST 16 Standard environment Not really defined.. Nist: Measuring device The real environment is full of reflections!! Usually measured in the DARK!: Reproducible, but there is no good relation to real use! example: brightness = 500 Cd/m2 Contrast ratio = 500:1 (brightness dark state = 1 Cd/m2) Environment = 500 Cd/m2 (diffuse) Front screen reflection = 3% (15 Cd/m2) Resulting contrast = 500 / (15+1) = 31:1 Window Office lighting Wall floor Photo: courtesy M. Becker, Display Metrology & systems 17
Luminance Pattern Calculation : Average of 9 points Measure Positions Others Long Range Non-uniformity : ( Lmax Lmin)/Lmax (%) V/2 V/10 Contrast Ratio(Dark room) : L_white / L_black H/10 H/2 자료 : 이정노박사 ( 삼성 SDI) 18 Color Pattern Calculation : Average of 9 points Measure Positions Others Correlated Color Temperature(CCT) : T = 437*n^3 + 3601*n^2 + 6831*n + 5517 (n=(xw-0.332)/(0.1858-yw)) CIE 1931 Gamut Area V/2 : Area ratio to NTSC - in CIE1931 (x, y) V/10 - in CIE1976 (u, v ) H/10 H/2 Color Non-uniformity : longest distance in CIE1976 자료 : 이정노박사 ( 삼성SDI) 19 CIE 1976
RGB Color Coordinates Color space ISO RGB Extended ISO RGB srgb (IEC 61966-2-1) ROMM RGB Adobe RGB 98 Rendered Encoding Gamut X X O O O 8-bit nonlinear 10~16 bit nonlinear 8-bit nonlinear 8-bit nonlinear (12-16 bit) 8-bit nonlinear White point Primaries Limited Floating Floating (ISO 17321) Unlimited Floating Floating CRT Wide Extended CRT D65 D50 D65 R(0.64, 0.33) G(0.30, 0.60) B(0.15, 0.06) R(0.7347, 0.2653) G(0.1596, 0.08404) B(0.0366, 0.0001) R(0.64, 0.34) G(0.21, 0.71) B(0.15, 0.06) 2007. 2학기 Standard RGB color spac Video RGB space Apple RGB O 8-bit nonlinear CRT NTSC RGB O Nonlinear CRT C D65 EBU RGB (CCIR 601) O Nonlinear CRT D65 ITU-R BT.709 O Nonlinear CRT D65 * ROMM(Reference Output Medium Metric/Kodak) R(0.625, 0.34) G(0.28, 0.595) B(0.155, 0.070) R(0.67, 0.33) G(0.21, 0.71) B(0.14, 0.08) R(0.64, 0.33) G(0.29, 0.60) B(0.15, 0.06) R(0.64, 0.33) G(0.30, 0.60) B(0.15, 0.06) Power Consumption Measure Pattern - 전류, 전압측정 Calculation Full White : Power(30) = 전류 * 전압 * 0.3 Issue on screen power consumption 휘도 : 150 cd/m2 Pattern : Full white * 0.3, 30 % Area, 30% gray, Pixel 격자, others? 측정예 Full White 30% Area 30% 휘도 Power Ratio 100% 29% 32% 자료 : 이정노박사 ( 삼성 SDI)
Power consumption: RGBW method RGB saturated color 를표현하는경우비슷한 power 를소모하지만, White 가들어가는일반적인화면을표시하는경우 RGBW 가약 ½ 수준의전력을소모함. D. Arnold, T.K. Hatwar, P.J. Kane, M.V. Hettel, M.E. Miller, M.J. Murdoch, J.P. Spindler, S.A. Van Slyke, K. Mameno, R. Nishikawa, T. Omura, S. Matsumoto, IMID 04 Digest 25-2 (2004) Cell Phone Power Consumption Comparison 소비전력 (mw) 2 IMT-2000 Cell phone, R:G:B = 3:6:1, 50% polarizer efficiency, 30 % of pixels lit AMLCDs 형광 AMOLEDs 200 고분자 AMOLEDs 인광 AMOLEDs 100 50 0 20 40 60 80 100 휘도 (cd/m 2 )
Average Picture Level ( APL ) Output = 100 x ( Input / 100 ) 2.2 : Gamma=2.2 Average Picture Level ( APL ) APL Type 1 ( Pre-Gamma ) Definition: APL is the time average of the video signal input voltage to the TV set, which is usually expressed as a percentage of the full white signal level voltage. APL Type 2 ( Post-Gamma ) Definition: APL is the time average of the average luminance of all pixels in the TV set, which is usually expressed as a percentage of the peak white luminance level. Ref. Dr. Larry F. Weber, 2005. 5. 8 IEC Meeting Average Picture Level ( APL ) Ref. Dr. Larry F. Weber, 2005. 5. 8 IEC Meeting
Measuring Method of Power Consumption JEITA Measuring Method Proposal Method of measuring annual energy consumption of LCD-TVs and PDP-TVs Po = 0.167 x Pw + 0.167 x Pb + 0.333 x Pc + 0.333 x Pt where: Po is the output power value that is used for the final power calculations, Pw is the measured power of the 100% white pattern, Pb is the measured power of the full black pattern, Pc is the measured power of the color bar pattern, Pt is the measured power of the white and black bar pattern. Other Measuring Method Proposal Dr. Weber s Proposal of New Test Method Po = W1 x P1 +W2 x P2 + W3 x P3 + W4 x P4 +.. + Wn x Pn ( 3 ) Where: Po is the output power value that is used for the final power calculations, P1, P2, P3,, Pn are the powers that are measured with the various test images, W1, W2, W3,, Wn are fixed numbers or Weights defined by the test method. Ref. Measuring Annual Energy Consumption of LCD-TVs and PDP-TVs By Dr. Larry F. Weber 2005. 5. 8 IEC Meeting Image Sticking initial long time operation OLED OLED
Differential Aging Image Burning Improvement of OLED Lifetime Development of Avoiding Driving Tech. White Balance Shift : Yellowish Problem Required the Same Lifetime of RGB Viewing Angle Normalized Luminance Normalized White Luminance with Viewing Angle 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 10 20 30 40 50 60 70 80 90 Viewing Angle (Degrees) Δu'v' Color Shift 0.04 0.03 0.02 0.01 White Color Shift with Viewing Angle 0 0 10 20 30 40 50 60 70 80 90 Viewing Angle (Degrees) Viewing angle based on luminance to be defined at X% luminance drop. 자료 : John Penczek (DuPont Displays) Viewing angle based on color shift be defined at 0.01 or 0.02 Δu v shift.
Moving Edge Blur Material response of OLEDs is very fast compared to LCDs Lesson from the LCD world: material response time is not a sufficient metric for moving image quality Possible artifacts in OLEDs arising from driving schemes Edge blur by spatio-temporal retinal averaging Dynamic false contours (grey scale by subfield modulation) Flashes during saccades (passive matrix OLED) Spatial high-pass filtering (ringing signal) How can we objectively measure and characterise these artifacts to fairly compare image quality with other technologies? 자료 : John Penczek (DuPont Displays) Daylight Contrast Daylight Illumination Levels Iluminance (lux) 0 2 5 10 20 50 100 500 1000 5000 10000 Outdoors, Evening Homes, Evening 2.5 Typical Office Environment Typical Home Environment Outdoors, Daylight 100 000 Transmissive LCD Spectral Intensity Wcm -2 (μm) -1 2.0 1.5 1.0 Blackbody radiationat 6000K Reflective LCD AM0 AM1.5 0.5 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Wavelength (μm)
Daylight Contrast Illuminance by Region/Season 65 deg North 0 deg Illuminance (Lux) 140,000 120,000 100,000 80,000 60,000 40,000 20,000 0 0 50 100 150 200 250 300 350 Day of the year Partly cloudy Cloudy sky Clear sky Illumination (Lux) 160,000 140,000 120,000 100,000 80,000 60,000 40,000 20,000 0 0 50 100 150 200 250 300 350 Day of the year Source: The IESNA Lighting handbook, 9th edition, chapter 8 High display illuminance levels are required for daylight readability measurements, or scale reflection measurements. Data from J. Bergquist (Nokia), IDW 2003 Daylight Contrast Diffuse Illumination Proposed Illumination Geometry Directed illumnation with a subtense of 0.5 θ s = 45 φ s = 0 θ d θ d = 0 Diffuse measurement Isolated source measurement (θ d =8 Example to 10 ) of sunlight readability testing configurations where two separate measurements are made at reduced illumination, numerically scaled to daylight levels, and combined. (E. Kelley, M. Lindfors & J. Penczek, ADEAC 2005)
ISO 13406-2 (TC159/SG4/WG2) Visual Display Requirements Definition of Pixel Faults A4/10 Pixel Faults ISO 13406-2 Types of Pixel Faults 1.Pixel, Sub-Pixel,,, 2.ISO 13406 Type 1,, Type 2 3.ISO 13406 Type 3,,, 4. ISO 13406 Cluster V1 5 Pixels X 5 Pixels V2 V3 V4 V5 H1 H2 H3 H4 H5 A5/10
Pixel Faults ISO 13406-2 Definition of Fault Classes, Classpixel A6/10 Pixel Faults VESA FPDM2, Jun 1, 2001 303-6A Defective Pixel Characterization and Measurement VESA FPDM2, Jun1 2001 is a copy right of Video Electronics Standards Association A7/10
Pixel Faults VESA FPDM2, Jun 1, 2001 303-6A Defective Pixel Characterization and Measurement VESA FPDM2, Jun1 2001 is a copy right of Video Electronics Standards Association A8/10 Mura Defects VESA FPDM2, Jun 1, 2001 303-8 Mura Defects VESA FPDM2, Jun1 2001 is a copy right of Video Electronics Standards Association A8/10
Mura Defects VESA FPDM2, Jun1 2001 is a copy right of Video Electronics Standards Association A9/10 IEC TC110: Flat Panel Display Devices IEC TC110 Flat Panel Display devices 의장 : Mr.Shigeo Micoshiba( 日 ) 간사 : Mr. Hideo Iwama( 日 ) Program member: 12 개국 Observer : 11 개국 규격수 : 17 개 ( 수정안 2 개 ) IEC TC47/SC47C WG1 Optoelectronic Semiconductor Devices for applications other Than fibre optic communications 의장 : Dr. Tetsuhiko Ikegami( 日 ) WG2 Liquid crystal & solid state Display devices 의장 : Mr. Katsumi Ishiguro( 日 ) (Sharp Co.,) WG4 Plasma Display Panels 의장 : Mr. Tsutae Shinoda( 日 ) (Fujitsu Lab.Ltd) 2002. 2. 22: 최초의 OLED 국제규격안제안 ( 일본 ) - OLED Terminology & Letter Symbols 2002. 10. 28 ~ 11. 1 북경 IEC 총회에서최초의 OLED Project 출범 (IEC PT62341: OLED Terminology & Letter Symbols), 한국 SC47C TCxx로의승격및 OLED WG 신설제안 2003. 6. IEC SMB 승인 : IEC TC47/SC47C TC110 2003. 12. 1 ~ 2: IEC TC110 Meeting, Fukuoka ; 이창희교수 OLED Area Manager로임명 2006. 2. 8: WG5 (OLED) 신설 WG5 OLED 의장 : 이창희교수 ( 서울대, 한국 ) PT62341-1-1 ( 이정노박사, 삼성SDI) PT62341-1-2 (K. Shibata, Sanyo, Japan) PT62341-4 (Y. Gao, Visionox, China) PT62341-5 ( 김광영 ( 삼화콘덴서 ) / A. Ikeda (Espec Co.) PT62341-6-2: J. Penzcek (NIST)
Progress of the IEC/TC110 OLED standardization Project 2002 2003 2004 2005 2006 2007 2008 2009 2010 IEC 62341-1-2 Terminology and letter symbols (K. Shibata) IEC 62341-1-1 Generic Specifications (J. N. Lee) IEC 62341-6-1 Meas. Methods of Optical and Optoelectrical Parameters (L. Wang) IEC 62341-5 Environmental and mechanical endurance test methods (K. Y. Kim) PWI IEC 62341-6-2 Meas. Methods of Visual Quality (J. Penczek ) 47C/272/NP 2002. 2. 22 47C/291/NP 2002. 12. 20 47C/290/NP 2003. 12. 20 110/20/CD 2004. 4.23 110/68/CD CDIS 2005. 6.102005. 10 110/38/CD 110/68/CD 2004. 12. 32005. 12. 2 110/55/CD 2005. 5.20 110/57/NP 2005.1.8 CDIS 2006. 10 CDIS 2006. 10 1 st CD 2006. 11 PWI 2006.1.20 CDV 2007.11 FDIS 2008.11 1 st CD 2007. 10 FDIS 2010.6