In this blog post, we’ll explore the operating principles of self-emissive AMOLED, its differences from LCD, its pros and cons, as well as the latest technological advancements and future applications.

The Principles of AMOLED and Its Popularization

The pace of scientific and technological advancement is accelerating with each passing year, and as a result, cutting-edge technologies are being rapidly integrated into various electronic devices used in our daily lives. However, for those who haven’t majored in related fields or don’t have a particular interest in them, it’s often difficult to understand in detail what technologies are incorporated into new products.
Nevertheless, some technical terms have become widely known to the general public. A prime example is AMOLED (Active-Matrix Organic Light-Emitting Diode). When Samsung Electronics actively used the term “AMOLED” in the mobile phones it launched in 2009 and promoted it through advertisements and jingles, the name “AMOLED” became more familiar to the public than the technical term “AMOLED.”

Technical Differences Between LCD and AMOLED

LCD stands for Liquid Crystal Display. It is a method of displaying colors by having liquid crystals selectively transmit light from a backlight located behind the screen in response to electrical signals. Simply put, the principle is similar to turning on a fluorescent light and placing colored cellophane sheets in front of it to create the desired colors.
In contrast, AMOLED is a display that uses OLED (Organic Light-Emitting Diode) technology, in which each pixel emits light on its own. OLED is a light-emitting diode that uses a carbon-based organic compound as its light-emitting layer; when an electric current flows through it, it directly emits light. Thanks to this characteristic, it can not only implement various structures—such as dots, lines, and surfaces—but can also be manufactured in extremely thin and flexible forms. Therefore, unlike LCDs, AMOLED is a self-emissive display that requires no backlight at all.
The “AM” in the name “AMOLED” stands for Active Matrix. To turn each pixel of the display on and off precisely at the desired time, a control circuit is required. In PMOLED (Passive-Matrix OLED), although the electrodes are arranged in a matrix, the circuit that controls the current is located outside the matrix. In contrast, AMOLED has a TFT (Thin-Film Transistor) built into each pixel, allowing for independent control of every single pixel. Simply put, PMOLED has a structure where the switches are located outside the screen, while AMOLED has ultra-small switches built into every pixel, enabling more precise and faster control.

Advantages of AMOLED

One of the biggest advantages of AMOLED is that it does not require a backlight, allowing for the production of extremely thin displays. This makes it particularly advantageous for devices where light weight and portability are key, such as smartphones, smartwatches, and tablets.
Another advantage is its exceptional ability to reproduce black. Since the backlight in an LCD is always on, some light may leak through even when the liquid crystal blocks it. In contrast, AMOLED completely turns off the pixels themselves when displaying black, enabling much deeper and purer blacks. This characteristic provides a high contrast ratio, creating the effect of a sharper and more three-dimensional screen.
Furthermore, since only the necessary pixels are activated, it offers the advantage of reduced power consumption in environments where dark screens are frequently used. This characteristic is one of the reasons why dark mode is widely used in recent smartphones.
AMOLED’s extremely fast response time is another advantage. Even in games with rapid screen transitions or high-refresh-rate display environments, it produces minimal motion blur, resulting in a smoother display. This advantage is actively leveraged in the latest smartphones, tablets, and laptops.

Disadvantages of AMOLED and Efforts to Improve It

A major disadvantage of AMOLED is the “burn-in” phenomenon. Burn-in refers to the phenomenon where, if the same image is displayed for an extended period, a faint trace of the previous image remains even after the screen is changed. While this phenomenon can occur in other displays as well, OLEDs are more prone to it because the organic light-emitting materials degrade gradually over time.
For example, if red is repeatedly displayed in a specific area for a long time, the brightness of the red OLED element may decrease before that of other pixels. Subsequently, when a white screen is displayed, the red brightness in that area may be relatively lower, causing the color to appear different. For this reason, consumer complaints related to burn-in issues were raised in the past.
However, the durability of OLED materials has improved significantly in recent years, and the implementation of various methods—such as pixel shifting, screen protection features, brightness control algorithms, and software calibration technologies—has substantially reduced the likelihood of burn-in compared to the past. Manufacturers are also continuing their research to enhance lifespan and durability by continuously improving organic light-emitting materials and drive technologies.
Another strength of AMOLED is its exceptional flexibility. The organic light-emitting layer can be manufactured to be extremely thin, making it ideal for creating bendable or foldable displays. These characteristics are already being applied in various products, such as foldable smartphones, flip phones, rollable displays, and smartwatches, and their range of applications is expected to expand further in the future to include automotive displays, wearable devices, and augmented reality (AR) and mixed reality (XR) devices.
As such, AMOLED is a display technology that offers numerous advantages—including excellent contrast ratios, fast response times, slim profiles, and superior design flexibility—based on its self-emissive nature. At the same time, technological development to address issues such as burn-in and lifespan is steadily progressing, and AMOLED is establishing itself as a core technology not only in smartphones and various other electronic devices but also across the entire next-generation display industry.