1、1Display and ComponentsOLED ModulesAdvanced Active Matrix OLED TechnologiesSteven A. Van SlykeDisplay and ComponentsOLED Modules Business UnitEastman Kodak CompanyRochester, New York, USA2Display and ComponentsOLED ModulesOutline Methods of Color Patterning Discussion of RGBW Format RGBW in imaging
2、applications Display Prototypes with RGB and RGBW White chemistry and formulation Display designs Processing and testing Power consumption of RGB and RGBW displays Importance of emitter white point Color filter array Operational Stability Conclusions3Display and ComponentsOLED ModulesCathodeETLHTLAn
3、odesSubstratePatterned RGB Emitting LayersWhite-Emitting Layer with RGB Color-Filter ArrayAdvantages High efficiency Good colorDisadvantagesTypically uses shadow maskingfor RGB patterning (yield, cost, scaleability) Aperture ratio issues (shadow mask) Differential aging of RGBAdvantages Unpatterned
4、emitting layer(no masks) Aperture ratio not affected by RGB patterning Enabled by high efficiency white Fewer OLED processing steps Reduced differential aging(white is very stable)Disadvantages Loss of efficiency due to filter absorption Gamut controlled by whitespectrumEmitting LayerWhite-Emitting
5、LayerRGBW-RGBMethods of Color Patterning(illustrated for bottom emitting)4Display and ComponentsOLED ModulesShadow Masking in ManufacturingTapered MaskEliminates Non-Uniformity Within Pixel Precision alignment subsystems: +/-3 m in production Tolerances across a 335 x 550 mm substrate: +/-15 m Signi
6、ficant concerns thermal expansion contact with (fragile) substrate cleaning without damage ability to scale to large substrates COST 5Display and ComponentsOLED ModulesExamples of RGB and White - RGB Displays(AMOLED)Kodak LS633 LTPS (521 x 218)2.2 ”Kodak / SanyoLTPS15 ”RGB direct patterned White wit
7、h RGB color filtersProducts PrototypeSony Clie PEG-VZ90LTPS (480 x 320)(Multi-media handheld)3.8 ”Neosol PMP LTPS (521 x 218)2.2 ”6Display and ComponentsOLED ModulesWhite-Emitting Layer with RGBW Color-Filter ArrayAdvantages Unpatterned emitting layer(no masks) High efficiency white sub-pixel result
8、s in significantpower reduction (a large portion of image content contains white) Enabled by high efficiency whiteDisadvantages Loss of efficiency due to filter absorptionWhite-Emitting LayerW-RGBWMethods of Color Patterning(illustrated for bottom emitting)7Display and ComponentsOLED ModulesRGB and
9、RGBW Formats (with W emitter) White OLED Color Filter Array Device EmissionAll sub-pixels filtered White sub-pixel unfiltered(display efficiency gain)Takes advantage of high efficiency, stable whiteFor imaging, takes advantage of fact that most images are very unsaturated (the world is gray)Approxim
10、ate Efficiencies(cd/A)2.6 6.6 1.1 12.52.6 6.6 1.1RGB Format RGBW Format12.5 cd/A 12.5 cd/A8Display and ComponentsOLED ModulesRGB and RGBW primary colors0.00.10.20.30.40.50.60.70.80.90.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9CIE xCIEyD65RedGreenBlueWhiteR G B R G B WShown for NTSC colorsand D65 white.9D
11、isplay and ComponentsOLED ModulesRGB and RGBW unsaturated colors0.00.10.20.30.40.50.60.70.80.90.00.10.20.30.40.50.60.70.80.9CIE xCIEyD65Emitting sub-pixelsRGB RGBWRed WhiteGreen GreenBlue Blue Red RedGreen GreenBlue WhiteRed RedGreen White Blue BlueShown for NTSC colorsand D65 white.10Display and Co
12、mponentsOLED ModulesImportance of Neutral Colors in ImagingProbabilityinDSCImages (based on 13,000 images)1931CIEX1931CIEYProbabilityin DSCImagesBased on 13,000 Digital Still Camera Images11Display and ComponentsOLED ModulesDisplay Power Consumption for RGB and RGBWAssumes W is fully utilized to red
13、uce powerC = 0%C = 100%Color SaturationRGBW / RGB power consumptionFor 13,000 DSC images, color saturation 50%0.00.10.20.30.40.50.60.70.80.90.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9CIE xCIEyD65RGBRGBW12Display and ComponentsOLED ModulesOutline Methods of Color Patterning Discussion of RGBW Format RGBW
14、 in imaging applications Display Prototypes with RGB and RGBW White chemistry and formulation Display designs Processing and testing Power consumption of RGB and RGBW displays Importance of emitter white point Color filter array Operational Stability Conclusions13Display and ComponentsOLED ModulesSu
15、bstrateITO AnodeHole Injection LayerNPB Hole Transport LayerYellow Emitting LayerBlue Emitting LayerAlq Electron Transporting LayerLiF / Al CathodeWhite OLED Layer Structure used for Prototypes0.00.20.40.60.81.0400 500 600 700 800Wavelength (nm)NormalizedRadianceCIE x 0.36CIE y 0.38Efficiency (cd/A)
16、 12.480.00.10.20.30.40.50.60.70.80.90.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.91931 CIEx1931CIEy(0.38, 0.36)D65 (0.313, 0.329)Note: Better power efficiency resultsif white point of emitter = D6514Display and ComponentsOLED Modules528 columns(176 x RGB)528 columns(132 x RGBW)220 rowsRGB and RGBW AMOLED T
17、est Layouts2.2”diagonal 198 x 66 u sub-pixel size. . . . . . . . . . . . . . . . . .RGB. . . . . . . . . . . . . . . . . .RGBW38720 pixels (RGB) (RGB = SQUARE)116160 subpixels29040 pixels (RGBW = RECTANGULAR)116160 subpixels15Display and ComponentsOLED Modules176(RGB) x 220132(RGBW) x 220RGB and RGB
18、W Test Layouts2.2”diagonal 198 x 66 u sub-pixel sizeRGB Pixel = 198 u x 198 uRGBW Pixel = 264 u x 198 uNote that this is a test format only.A better comparison would be with 176(RGBW) x 220. 2.2 inch diagonal16Display and ComponentsOLED ModulesPrototype Process Flow6” x 6” substratewith four 2.2” di
19、splays= AMOLED - RGB Color Filter Array= AMOLED - RGBW Color Filter ArrayCoat organic and Cathode layersScribe / breakTest9 Identical white formulation used for both RGB and RGBW17Display and ComponentsOLED Modules0.00.10.20.30.40.50.60.70.80.90.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9CIE xCIEyGRBWD65R
20、GBWCIE x0.640.320.120.36CIE y0.360.550.150.38cd/A 2.63 6.6 1.14 12.5Prototype Characteristics0.00.20.40.60.81.0400 500 600 700 800Wavelength (nm)NormalizedRadianceCIE x 0.36CIE y 0.38Efficiency (cd/A) 12.48Note: Efficiency and colorsdepend on color filter selection18Display and ComponentsOLED Module
21、sData LineData Storage Capacitor (keeps Vg constant during frame time)Power TransistorVg level controls gray scaleWrite Transistor(acts as switch to allow data to be written to power transistor)Data Line (applies voltage to power transistor gate)Row Scan LineCapacitor LinePower Line(Vdd = 13 volts)
22、OLEDCommon Cathode(unpatterned cathodefilm common to all pixels)NOTE: Standard Two-Transistor Design Used 19Display and ComponentsOLED ModulesTest Methodology Determine luminance-current-chromaticity characteristics for each color channel (R,G,B, and W) Display images that have been appropriately pr
23、ocessed for RGB and RGBW displays Measure the total panel current for each image Calculate the power consumption for each image Power = Panel current x 13 volts Compare power consumption of devices RGB vs. RGBW (Note: these are both with white emitter / color filter arrays)20Display and ComponentsOL
24、ED ModulesRGBW DisplayDisplay “on”Display “off”Display “off”21Display and ComponentsOLED ModulesRGB176 (RGB) x 220RGBW132 (RGBW) x 220RGB and RGBW Displays22Display and ComponentsOLED Modules22RGBW132 (RGBW) x 220RGB176 (RGB) x 220RGB and RGBW Displays23Display and ComponentsOLED ModulesOutline Meth
25、ods of Color Patterning Discussion of RGBW Format RGBW in imaging applications Display Prototypes with RGB and RGBW White chemistry and formulation Display designs Processing and testing Power consumption of RGB and RGBW displays Importance of emitter white point Color filter array Operational Stabi
26、lity Conclusions24Display and ComponentsOLED ModulesRGB and RGBW Power Consumption2.2” diagonal, 100cd/m2white after 44% T circular polarizer01002003004001 2 3 4 5 6 7 8 9 10111213Image NumberPowerConsumption inmWW-RGBWW-RGBAverage for 13,000 images:180 mW - RGBW340 mW - RGB25Display and ComponentsO
27、LED ModulesImportance of Emitter White = Display WhiteRelative white emitter efficiency (cd/A) to attain equal RGBW display power. = D65Target display white point = D65Conclusion very important that emitter white is close to display white point for lowest power consumption.26Display and ComponentsOL
28、ED ModulesConclusions Power Consumption9 The RGBW format requires the power compared to the RGB format agrees with model prediction.9 If the emitter white point is not at the display white point, (D65), the efficiency (cd/A) needs to be higher for equivalent power consumption.27Display and Component
29、sOLED ModulesOutline Methods of Color Patterning Discussion of RGBW Format RGBW in imaging applications Display Prototypes with RGB and RGBW White chemistry and formulation Display designs Processing and testing Power consumption of RGB and RGBW displays Importance of emitter white point Color filte
30、r array Operational Stability Conclusions28Display and ComponentsOLED ModulesOperational Stability White Channel 0.50.60.70.80.91.01.10 500 1000 1500 2000 2500 3000Operating time (hours)NormalizedLuminance (cd/m2)5 mA/cm210 mA/cm220 mA/cm240 mA/cm280 mA/cm2T-Z030-2-4WTest condition: white sub-pixels
31、 operatedWhite sub-pixel current density (mA/cm2)Initial areal luminance (cd/m2) Initial sub-pixel luminance (cd/m2)Time to 1/2 luminance (hrs)5 40 561 20000 (est.)10 83 1165 10000 (est.)20 166 2330 5000 (est.)40 336 4716 183080 660 9263 585Note: Aperture ratio = 0.285White ratio = 0.25 Fraction emi
32、tting = 0.071329Display and ComponentsOLED ModulesOperational Stability Model Results 0.50.60.70.80.91.01.10 500 1000 1500 2000 2500 3000Operating time (hours)NormalizedLuminance (cd/m2)5 mA/cm210 mA/cm220 mA/cm240 mA/cm280 mA/cm2T-Z030-2-4WAMOLED Stability ModelingInputs:Display LuminanceTarget whi
33、te pointColor filter propertiesContrast filter propertiesWhite stability at various current densitiesWhite emission spectrumWhite efficiencyAperture ratio limitsAverage DSC imagesOutputs:Average current density Lifetime estimateFor the display in this presentation, average current density = 7.3 mA/c
34、m2.Stability (T1/2) estimated at 13,000 hrs.9 180 cd/m2peak white with 44% Tpolarizer9 DSC imagesWhite sub-pixel current density (mA/cm2)Initial areal luminance (cd/m2) Initial sub-pixel luminance (cd/m2)Time to 1/2 luminance (hrs)5 40 561 20000 (est.)10 83 1165 10000 (est.)20 166 2330 5000 (est.)40
35、 336 4716 183080 660 9263 58530Display and ComponentsOLED ModulesConclusions9RGBW displays require the power as analogous RGB displays for imaging applications, with no loss in gamut.9Operational stability of RGBW displays is excellent, and is same as RGB displays. 9For optimum power consumption, it is important that the white emission is close to the target display white point (e.g. D65).
