ABSTRACT
Guidelines............................................ 372 8.3 AMOLED TFT Pixel Circuit Examples ..................... 374
8.3.1 Voltage Addressed Pixel Circuit with 2TFTs........................................................ 375
8.3.2 Voltage Addressed Threshold Voltage Compensation Circuit....................................... 377
8.3.3 Current Copy Pixel Circuit with 4TFTs......... 379
8.3.4 Amorphous Silicon Current Addressed Pixel ................................................................... 381
8.3.5 Amorphous Silicon Threshold Voltage Compensation Circuit....................................... 382
8.3.6 Amorphous Silicon Voltage Addressed Circuit................................................................ 382
8.4 Pixel Layouts and Fabrication ................................... 383 8.4.1 Pixel Layouts and Device Sizing..................... 383 8.4.2 TFT Fabrication................................................ 385
8.5 Summary...................................................................... 389 References............................................................................. 389
8.1 INTRODUCTION
Liquid crystal displays (LCDs) have now been on the market for a number of years; however, recent enhancements on organic light-emitting devices (OLEDs) offer a new alternative to the flat panel display industry. OLEDs offer improved luminous efficiency, high brightness, and excellent viewing angle. In addition, OLED displays have thinner profiles, weigh less, and consume less power than LCDs. Other interesting aspects of this new technology are the flexible display and flexible electronics product solutions it offers. Because of their emissive nature, OLED displays do not require a backlight, which makes this technology a lower-cost and more suitable alternative to flexible display applications. OLED displays facilitate the implementation of displays on plastics and metal foils, which make for more rugged and lighter products. Furthermore, when using flexible substrates, these displays could ultimately be fabricated using cheaper processing techniques such as roll-to-roll processing.
