Hyun Jae Kim. Yonsei University

Transcription

1 Recent development in Electronic Paper Technology Hyun Jae Kim Yonsei University kr

2 Do you remember what it was like 25 years ago? Motorola DynaTAC 8000X Some quick facts LG PRADA 1,305 cm 3 Volume 70 cm 3 785g Weight 95g LED (red) Display TFT-LCD + Touch Pad

3 Convergence One device with multiple applications & Simple UI Display size & Characteristics Low resolution SMono/color Small MP3 DSC P-DVD Game *Source: Apple Touch screen High ppi Full color Fast response Slim & compact Me edium Smart Phone/UMPC *Source: SONY Large size Full color Low ppi La arge PDA PMP Mobile PC Note PC *Source: Samsung

4 Future Technologies Display DTI Direct View Projection 3-D CRT FPD Flexible Emissive Non-Emissive CDT CPT VFD STN-LCD CRT U.S. Army research Lab. LED TFT-LCD LCD FED EPD/PLD LCOS PDP DMD OLED

5 New displays Flexible display Flexible displays enable robustness & freedom in design Paper like Display E - paper E - book Rollable display Low-end Phones Robust Low-price (Roll-to-roll process) *Source : Nokia High-end Unique design Multimedia High functionality Devices

6 Flexible Display Technologies Substrate TFT Array Display Mode Thin Glass Plastic Film Metal Foil a-si TFT Poly-Si TFT Organic TFT Oxide TFT LCD Electrophoretic OLED

7 Flexible Display Technologies Source : Displaybank

8 E-Paper Technologies Paper Cholesteric LCD Electrophoretic Electrowetting Driving Voltage - 10V 15V 20V C/R 10~ Refresh Time 10 sec 0.7 sec 10 ms Reflectance 40~80% 30% 45% 60% Color B/W ~ Full color 4096 color (3 panel) B/W 16 grey 4096 with C/F 4096 color (3 panel) Driving - Passive Active Active SEM images of Paper Schematic F e F ca l p Diagram V oil pushed aside

9 Three Expectations of E-Paper Flexibility Thin : Wearable Computer Flexible : Roll-up display Light : Portable TV Readability Less Fatigue : e-book Comfortable : e-newspaper Multi-Functionality Input Function : Ubiquitous display Sound Function : Paper PC Radio-Communication Function

10 Electrophporetic Display Top transparent electrode Subcapsule addressing enables hi-resolution display capability Light State Clear Fluid Positively charged white pigment chip Negatively charged black pigment chips Bottom electrode Dark State Liquid Crystal BackLight Polarizer Color Filter Color Filter Glass TFT Glass Polarizer E-Ink Display Structure TFT LCD Structure

11 Structure of LIBRI`e System Block Diagram Panel Structure 1 frame memory Look-up Table Active Matrix Microencapsulated Electrophoretic Data and Scan Driver Shift Register Level Shifter Output Buffer Color Filter RGBW DAC S/H and Latch

12 Operational Principle(1) Using the Positively Charged White pigment and Negatively charged black pigment Reflective mode Operation Voltage : -15v ~ +15v High Resolution TiO2 diameter 0.5 um Display Image Carbon 45 ~ 106um Moving Picture for MEPD Operation Microencapsulated Electrophoretic Display Click!

13 Operational Principle(2) : Gray Level Expression Differential Driving Control the pulse length Sensitivity to polarity To Solve Gray Error Very precise graytones can be achieved in a scheme wherein the display is driven multiple times to optical extremes before being driven to the final graytone

14 Microcup Sipix : Microcup Roll-to-Roll Process

15 Electrowetting Philips : Electrowetting Using a highly hydrophobic material Gyricon : Twist Ball type

16 QR-LPD Bridgestone : QR-LPD(Quick Response liquid powder display) Using Liquid Powder High Operation Voltage 200V

17 Recent Technical Issues Color Using Color Filter : High Price and Low legibility Without Color Filter : Color Printing, Color particle Gray Level Depends on application e-book : 4 Gray Movie : Real color Display devices with motion picture capability have wrongly been understood as being automatically acceptable for static documents Response Time MEPD : ~ 300 ms High Speed Response Time : Liquid Powder and electrowetting Reliability Never crash, Stable operation in high speed driving Organic TFT Low price process : Roll to Roll processing, Flexible O-TFT display Flexible substrate Plastic Substrate, Low temperature process -16-

18 E-Paper Applications

19 E-Paper Applications

20 Thank You