In this blog post, we’ll examine the evolution of displays—a core component of smart devices—from LCD to AM OLED, as well as the operating principles, pros and cons, and future potential of these two technologies.

The Evolution of Smart Devices and Display Technology

Now, several years after Apple launched the iPhone, competition in the smart device market is fiercer than ever. The relentless competition to improve the performance of core components—which essentially determine the performance of the devices themselves—presents a challenge to countless corporate researchers: they must develop new technologies. Displays, in particular, are key components that directly present information to users, and companies are constantly rolling out advertisements highlighting the performance of their displays. In the past, the technology at the center of this competition in the smart device market was LCD (Liquid Crystal Display).
LCDs, epitomized by Apple’s famous Retina Display, are a long-established technology that has been widely used in TVs and monitors since long before the widespread adoption of smart devices. Since LCDs do not emit light on their own, they rely on a backlight to provide illumination and display images by using an optical structure—comprising a liquid crystal layer, color filters, and polarizing filters—to produce the necessary colors and brightness. While this structure has served as the foundation for LCD’s long-term development, it has also created technical limitations. Because it requires a backlight and multiple optical layers, there were constraints on simplifying the structure or making it extremely thin compared to self-emissive displays. Additionally, since black is rendered by blocking or adjusting the light from the backlight, there were limitations in achieving a perfect contrast ratio. Furthermore, since the display itself does not emit light, its structure was not well-suited for creating flexible displays. Of course, as LCD technology has continued to advance—with the adoption of various technologies such as LED backlights and local dimming—these limitations have been significantly improved. However, structural differences still exist when compared to self-emissive displays. This is similar to how, even as technology advances and performance improves, it is difficult to completely eliminate the structural characteristics that the technology had from the very beginning.

AM OLED: Moving Beyond the Limitations of LCD

In this context, a new alternative emerged: AM OLED (Active Matrix Organic Light Emitting Diode), also known as AMOLED. OLED, which had been under research since the time LCD was gaining attention as a new technology and being commercialized in the display market, grew rapidly as it began to be widely adopted in various electronic devices, including smartphones. The display that Samsung introduced under the name “Super AMOLED” is also based on AMOLED technology. OLED is a technology capable of addressing the various structural limitations inherent in LCDs in a different way.
How can AM OLED be relatively free from the problems associated with LCDs? To understand why, we need to grasp the most fundamental difference between the two technologies. The difference between LCD and AM OLED can be metaphorically described as “LCD is subtraction, while AM OLED is addition.” LCD uses light from the backlight as its starting point. As the light from the backlight passes through structures such as the liquid crystal, color filter, and polarizing film, only the necessary light is selectively transmitted to produce the final color. In contrast, in AM OLED, each pixel that makes up the screen emits light on its own. Starting from a state where no light is emitted, by generating red, green, and blue light at the appropriate brightness levels in the necessary pixels, a wide range of colors can be produced.
Organic light-emitting diodes make this method possible. OLEDs utilize the property whereby light is emitted from the organic light-emitting layer when an electric current flows, allowing each pixel to be controlled independently. Therefore, they do not rely on a separate backlight like LCDs do. The basic light-emitting structure of an OLED includes a light-emitting layer made of organic material and operates on the principle that energy is released in the form of light when electrons and holes meet in the organic light-emitting layer. In AMOLED displays, active-matrix circuits, such as thin-film transistors (TFTs), are used to precisely control each individual pixel. Thanks to this self-emissive technology, the display structure can be made thinner and lighter, which is advantageous for designing thin and lightweight products like today’s smart devices.
The absence of a backlight also offers a significant advantage in terms of picture quality. Since an LCD’s backlight continuously emits light, even when displaying black, some light may leak through rather than being completely eliminated. While technologies such as local dimming can partially turn off or dim the backlight in dark areas to produce deeper blacks, they do not completely turn off the entire screen on a per-pixel basis. In contrast, since each pixel in an OLED emits light on its own, turning off the light emission of a specific pixel results in true black—no light is emitted. Because of this characteristic, OLEDs are well-suited for achieving high contrast ratios and crisp images.
Furthermore, the lack of a backlight makes it easier to create flexible displays. Conventional LCDs faced limitations in bending freely because multiple rigid components, including the backlight, had to be bent together. In contrast, OLEDs can be used to create flexible displays by utilizing flexible substrates and thin-film structures; in fact, OLEDs are currently used in a variety of foldable and bendable products, including smartphones. The “G Flex,” previously introduced by LG Electronics, was also a prime example of this flexible OLED technology.

What challenges does AM OLED need to overcome?

However, AM OLED is not a perfect technology that has solved every problem. Alongside the advantages of OLED, there are challenges that need to be addressed. One of the most notable issues is burn-in. Since OLEDs use organic light-emitting materials, prolonged use with pixels repeatedly emitting light can cause the light-emitting characteristics of individual pixels to change differently over time. In particular, if the same image—such as the same character or icon—is displayed in a specific area for an extended period, the pixels in that area may degrade faster than those in other areas, leaving a trace of the previous image.
This is commonly referred to as “burn-in.” Therefore, rather than understanding burn-in simply as a phenomenon where organic material decays and disappears like food, it is more accurate to view it as a result of the cumulative degradation of organic light-emitting devices and the accumulation of differences in luminance between individual pixels. This characteristic has been one of the factors raising concerns about long-term use, despite the many advantages of OLED. However, as OLED technology has advanced, continuous improvements have been made to the light-emitting materials, driving methods, pixel structures, and degradation compensation technologies. Recently, new structural and material technologies have also been developed to increase the lifespan and efficiency of OLEDs. Compared to when OLEDs first appeared, their lifespan and performance have improved significantly, and they are now widely used not only in smartphones but also in various fields such as TVs, tablets, laptops, monitors, and automotive displays.

Which technology is superior: LCD or AM OLED?

While AM OLED is rapidly growing as an alternative capable of overcoming the limitations of LCD, this does not mean that LCD has simply become an outdated technology with no further significance. Based on technology accumulated over many years and high production efficiency, LCD is still used in a wide range of products and holds an important position in various markets, including those for large-size displays. On the other hand, OLED has expanded its applications—particularly in smartphones, premium TVs, laptops, monitors, and automotive displays—thanks to advantages such as high contrast ratios, fast response times, a thin and lightweight structure, and the potential for flexible displays.
Therefore, rather than concluding that one of these two technologies is absolutely superior in all areas, it is more accurate to view the appropriate technology as varying depending on the product’s intended use and requirements. LCD is a stable technology that has evolved over a long period, while OLED is a technology that has overcome the limitations of existing displays in a different way, based on a new self-emissive structure. In particular, through continuous technological development, OLED has improved upon issues such as lifespan, efficiency, and brightness; as of 2026, it has been commercialized across a diverse range of product lines to the extent that, unlike in the past, it can no longer be simply referred to as “the technology of the future.”
Ultimately, the evolution of display technology is not so much a process in which one generation of technology simply replaces another, but rather a process of creating new possibilities by refining the strengths and limitations of each technology. While LCD laid the long-standing foundation for the display industry, AM OLED has expanded the forms and applications of displays through the new method of self-emission. Going forward, OLED technology must not rest on its current strengths but must continue to address challenges such as lifespan, efficiency, brightness, and production costs. If these advancements continue, the displays we use will not only become thinner and lighter but are also likely to evolve into far more diverse forms—such as being foldable, bendable, or taking on entirely new shapes—than they do today.