Active-matrix organic light-emitting diode or AMOLED is a display technology that has become popular in different electronic devices such as smartphones, tablet computers, digital cameras, media players, smartwatches and even television sets.
Note that this display technology is a reapplication of organic light-emitting diode or OLED technology. OLED is a type of electroluminescent technology in which organic-based materials emit light in response to an electric current.
The application of OLED technology in display panels requires the simultaneous switching of individual organic compounds, each representing an individual picture element or pixel. An AMOLED display technology addresses this through active matrix switching, particularly by attaching each pixel to a transistor and capacitor to actively maintain the pixel state while addressing other pixels.
Advantages of AMOLED
1. Energy efficiency: Lower power consumption when compared against other display technologies such as LED and LCD is one of the advantages of AMOLED.
Note that each diode in an AMOLED panel emits light without generating too much heat. Thus, unlike LED and LCD, energy loss due to heat transfer is lesser in this display technology.
Furthermore, because each diode or pixel generates light itself, an AMOLED panel does not require backlighting for colors and images to become visible unlike in LCD. Remember that backlighting requires drawing additional power from an energy source.
Power consumption is also relatively uneven in this display technology, focusing mostly on active pixels as represented by visible colors. Darker colors consume less power. On the other hand, blacks do not consume power because they are actually representing inactive pixels.
The energy efficiency of AMOLED panels makes them suitable for use in portable and battery-operated electronic devices. This energy efficiency also means that eco friendliness is another advantage of AMOLED.
2. Thinness: A conventional AMOLED panel has an organic plastic layer with a thinness of about 100 to 500 nanometers. This is about 200 times thinner than the strand of human hair.
This thinness also translates to lightness and flexibility. To be specific, the organic plastic layer of AMOLED is thinner, lighter, and more flexible than the rigid crystalline layers of LCD display. More light passes through because of this thinness, thus producing a brighter luminescence than a typical LED.
Nonetheless, this advantage leads to the design and development of innovative form factors. Using an AMOLED panel allows manufacturers to produce devices that are thinner. Several manufacturers have introduced curved displays and novel displays that are not only ultrathin but can also be rolled or folded.
3. High contrast ratio: High contrast ratio or the difference between the brightest whites and the darkest blacks is another advantage of AMOLED. This advantage is very evident when compared against other LCD display technologies such as in-plane switching or IPS and twisted nematic or TN technologies.
A typical AMOLED has higher artificial contrast ratio because each of its diode or pixel of organic material emits lights and produces color. Its deep blacks are also incomparable with other display technologies. These blacks are not artificially produced unlike in LCD because they are essentially a product of the absence of light.
4. Overall display quality: With deep blacks coupled with high contrast, the images displayed on an AMOLED panel are brighter and more vivid than the images display on typical IPS and TN panels.
This display technology also has better viewing angle than high-end IPS panels. There are no noticeable color shifts and brightness and vibrancy remain unchanged even when viewed from extreme angles.
AMOLED panels also have better response time and refresh rates than conventional IPS panels. This means that moving images are more fluid and less straining to the eyes.
Disadvantages of AMOLED
1. Short lifespan: A significant limitation of AMOLED is its shorter lifespan or evident degradation when compared against other display technologies such as twisted nematic, virtual alignment, and in-plane switching TFT-LCD technologies.
Organic materials found in an AMOLED panel have shorter lifespan than the materials found in LED and LCD. It is also worth mentioning that the pixels or color-specific organic materials in the panel have varying lifespan. For example, red and green materials have longer lifespan than blue materials.
This limitation translates further to other disadvantages. The varied lifespans of different color-specific organic materials means some pixels fade faster than other pixels, thus resulting in the development of very noticeable color shifts.
High susceptibility to screen burn-ins is also a notable disadvantage of AMOLED panels resulting from the short and varied lifespan of color-specific organic materials. Because certain pixels fade faster than other pixels, the collective process leaves permanent imprints of overused static images. Dead pixels will also appear over time.
2. Vulnerability to water: AMOLED panels are very prone to water damage. Organic materials are essentially highly vulnerable to water unlike the diodes in LED and inorganic crystalline found in LCD.
Submerging an AMOLED panel in water will immediately result in noticeable damages as represented by screen burn-ins or dead pixels. This vulnerability makes sealing process an important consideration in the fabrication and manufacturing of AMOLED panels.
3. Poor visibility: Images in an AMOLED panel is difficult to view under direct sunlight as compared against IPS panel. Some AMOLED panels are barely viewable under this condition. This limitation stems from the reduced brightness of this display technology and the absence of backlighting.
Several workarounds have been implemented to resolve this problem. These included reducing the size of gaps between layers within the panel to reduce reflectivity or the application of coating on screen to improve transparency and visibility.
4. Overall display quality: Despite its deep blacks and vivid colors, some AMOLED panels from specific manufacturers are prone to producing oversaturated colors that are too extreme and harsh. This means inaccurate color reproduction and representation.
This disadvantage means that this display technology might be unsuitable for color critical works such as photo editing, graphic design, and video editing.
Conclusion: Advantages and disadvantages of AMOLED
With vivid colors, deep blacks, and wide viewing angle, the visual experience with an AMOLED panel is incomparable with other display technologies. These are the critical advantages of AMOLED panels that made them a popular display option in modern consumer electronic devices.
The possibility of producing innovative form factors is also another advantage of AMOLED. This display technology supports the design and development of thin and flexible electronic displays.
However, the relatively shorter lifespan of this display technology when compared against IPS or TN LCD technologies is a very important limitation. This limitation collectively affects the lifespan of a consumer electronic device that used an AMOLED display.
The short lifespan and subsequent disadvantages of AMOLED such as susceptibility to color shifts and screen burn-ins make this display technology unsuitable for use in other types of consumer electronic device. Take note of computer or laptop monitors as an example.
Images in computers or laptops are usually static. Static image shortens further the lifespan of individual pixels or color-specific organic materials.
High demands for products with shorter product lifecycle such as smartphones and tablet computers coupled with market competition offset the problem concerning the short lifespan of AMOLED panels. Possibly, by the time an AMOLED panel starts demonstrating widespread pixel degradation, a user would have bought and owned a newer device.
Further readings: Several information from the article were obtained from the review article Purohit, V., Banu, T., & Daiya, K. 2012. AMOLED: An Emerging Trend in LED. International Journal of Scientific & Engineering Research. 3(1)