Technology
| Active-matrix Oled (Active-matrix organic light-emitting diode or Amoled) is a display technology for use in mobile devices and televisions. Oled describes a specific type of thin film display technology in which organic compounds form the electroluminescent material, and active matrix refers to the technology behind the addressing of pixels. Amoled technology is currently used in mobile phone and media players[1] and continues to make progress towards low power, low cost and large size (for example 40 inch) for applications such as televisions.[2][3][4]
Samsung‘s Super Amoled is a variant of Amoled technology in which the layer which detects touch is integrated into the touchscreen display rather than being overlaid on top. This results in a thinner device and improved outdoor performance.[5][6] |
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Technical explanation
Schematic of an active matrix OLED display An active matrix OLED display consists of a matrix of OLED pixels that generate light upon electrical activation that have been deposited or integrated onto a thin film transistor (TFT) array, which functions as a series of switches to control the current flowing to each individual pixel.[7] Typically, this continuous current flow is controlled by at least two TFTs at each pixel, one to start and stop the charging of a storage capacitor and the second to provide a voltage source at the level needed to create a constant current to the pixel and eliminating need for the very high currents required for passive matrix OLED operation.[8] TFT backplane technology is crucial in the fabrication of AMOLED displays. Two primary TFT backplane technologies, namely polycrystalline silicon (poly-Si) and amorphous silicon (a-Si), are used today in AMOLEDs. These technologies offer the potential for fabricating the active matrix backplanes at low temperatures (below 150°C) directly onto flexible plastic substrates for producing flexible AMOLED displays.[9] AdvantagesOLED technology has several advantages over LCD technology such as faster response times, wider viewing angles, light weight and durable displays, better power efficiency and brightness and lower cost.[10] Active-matrix OLED displays provide higher refresh rates than their passive-matrix OLED counterparts, and they consume significantly less power.[11] This advantage makes active-matrix OLEDs well suited for portable electronics, where power consumption is critical to battery life. The amount of power the display consumes varies significantly depending on the color and brightness shown. As an example, one commercial QVGA OLED display consumes 3 watts while showing black text on a white background, but only 0.7 watts showing white text on a black background.[12] OLED displays can be fabricated on flexible plastic substrates[9] leading to the possibility of rollable displays being fabricated. Compared with first generation AMOLED technology, the claimed advantages of Super AMOLED are displays that are 20% brighter, have 80% less sunlight reflection and 20% reduced power consumption.[13] DisadvantagesAMOLED displays may be difficult to view in direct sunlight compared to LCD displays.[14] Samsung’s Super AMOLED technology addresses this issue by reducing the size of gaps between layers of the screen.[5][15] The organic materials used in AMOLED displays are prone to degradation. However, technology has been developed to compensate for material degradation.[16][17] |
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GeneralConsumers are turned on by the bright, clear pictures produced by Organic Light-Emitting Diode (OLED) televisions—but they are tuning out to the small sizes and prohibitively high prices of these sets. Because of this, shipments of OLED panels for televisions will account for only a tiny portion of the global TV market during the next six years, despite a nearly 200 times increase in Active-Matrix OLED (AM-OLED) panel revenue during the same period, according to iSuppli Corp.
Global revenue from shipments of OL ED panels for use in televisions will surge to $1.8 billion in 2015, up from $10 million in 2009. This will make television the biggest revenue-generating application for OLED panels in 2015, surpassing the much higher-volume market of main displays for cell phones. The large sizes of televisions relative to the small displays on cell phones means the pricing for their OLED displays is dramatically higher, boosting revenue. However, even with this growth, unit shipments of OLED panels for televisions will amount to just 850,000 units in 2013 and only 4.7 million units in 2015, up from 25,000 in 2009. This represents a tiny number of shipments compared to the LCD-TV panel market, which is set to reach 232.6 million units in 2013. “Ever since Sony Corp. unveiled an 11-inch Active Matrix (AM) OLED television in late 2007, consumers and the display industry have been buzzing about its stunning images,” said Vinita Jakhanwal, principal analyst, small/medium displays, for iSuppli. “But average pricing for an 11-inch AM-OLED television is presently about $2,500, compared to $704 for a 42- to 44-inch LCD television. Due to manufacturing challenges and limited production, OLED-TVs will remain small in size and high in price in the coming years, consigning them to small niche of the global television market at least through 2015.”
OLED Allures Beyond the obvious attribute of superior image quality, AM-OLEDs have a very slim form factor. They also consume much less power than LCDs, making them attractive to environmentally conscious consumers. OLED Obstacles “The AM-OLED market presently has few suppliers,” Jakhanwal said. “This precludes competition that could drive prices down and volume up.” There currently is no investment in fabs capable of producing larger AM-OLED panels that can compete directly with the most popular LCD-TV sizes. Because of this, it is unknown whether high-volume manufacturing of large-sized AM-OLED panels can generate yields that are competitive with other display technologies. OLED panels are based on a current-driven backplane technology that offers poor stability and a lack of uniformity. Lifetime issues are also a concern, with large-sized AM-OLED TV sets’ operational life constrained by the OLED material performance and differential aging of the various materials in the display. AM-OLEDs also suffer from “image sticking,” a phenomenon that leaves an artifact on a screen after a static image is displayed too long. On the competitive front, LCD-TVs are improving their refresh rates, moving from 120Hz to 180Hz and 240Hz. They also are using LED backlights to improve color performance. Furthermore, LCDs are getting thinner, reducing a key advantage of OLEDs. Finally, TFT-LCD prices are dropping quickly, expanding their cost edge over OLEDs. Read More, Next Phase of OLED Volume Production Entails Tough Challenges > Two primary TFT backplane technologies, poly-Silicon (poly-Si) and amorphous-Silicon (a-Si) are used today in AMOLEDs. Why is AMOLED the future?High Perceived Luminance Contrast ratio Wide Viewing Angle True Colours Fast Response Devices with AM-OLED Displays:Nokia N85ZDNET about the Nokia N85 with a 2.6 inch 240×320 OLED display with support for up to 16 million colors: Nokia N85 with an 2.6″ LCD TFT vs AMOLED Display See the different between OLED and LCD at Samsungs WB1000 digital camera: Kodak World first Wireless PhotoframeEastman Kodak Company today introduced the world’s first consumer-available wireless picture frame featuring innovative Organic Light Emitting Diode (OLED) technology, a Kodak invention that produces exceptionally sharp and vivid image quality. The frame will be on display at the Kodak booth (Hall 5.2) at Photokina. Samsung NV24HD
See the different beetween LCD and AMOLED Displays |
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