It has been reported that domestic smartphone manufacturers plan to launch smartphones equipped with MicroLED displays by 2028. Apple began investing in MicroLED research as early as 2018. The high-end smartphone display market, currently dominated by OLED (Organic Light-Emitting Diode) technology, is expected to undergo a significant transformation.
With the rapid growth of emerging applications such as consumer electronics, automotive displays, AR/VR, AI glasses, wearables, and medical displays, microdisplay technologies—including MicroLED, MicroOLED, LCOS, DLP, and MiniLED—are becoming a central driving force in the global display industry.
LCD
LCD stands for “Liquid Crystal Display.” The market today largely uses TFT-LCD (Thin-Film Transistor Liquid Crystal Display) technology. It consists of a layer of liquid crystals sandwiched between two glass substrates. The upper glass substrate contains color filters, while the lower glass embeds transistors. When an electric current passes through the transistors, the resulting electric field alters the original orientation of the liquid crystal molecules, twisting them to change the rotation of light passing through. This variation in light rotation is filtered through the color filters to produce different colors.
LED
LED stands for “Light-Emitting Diode.” It converts electrical energy into light energy. When a voltage is applied across the positive and negative terminals of a semiconductor, electrons recombine with holes, releasing the excess energy as visible light. Depending on the materials used, photons of different energies generate light of different wavelengths. Direct-view LEDs are commonly used in outdoor video walls or traffic lights, while LED chips are the mainstream choice for television panels, screen backlighting, and lighting products.
OLED
OLED stands for “Organic Light-Emitting Diode.” Its basic structure involves depositing a layer of organic emissive material onto an indium tin oxide (ITO) glass substrate, then covering it with a low-work-function metal electrode. When driven by an external voltage, holes from the anode combine with electrons from the cathode within the emissive layer, generating energy and emitting light. Different materials produce red, green, and blue primary colors, forming the basic color spectrum.
LCD, OLED, and MicroLED
MiniLED and MicroLED
The most apparent difference between MiniLED and MicroLED lies in the size of the LED chips, but conceptually, there are distinctions as well. MiniLED, formally called “sub-millimeter LED,” refers to LEDs with crystals typically around 100 μm in size. MicroLED, or “micro light-emitting diode,” has crystal sizes generally below this threshold.
A single MiniLED is roughly 0.1 mm, about one-fifth the size of a standard LED. Its smaller size allows more LEDs to be packed into the same area, but it is not yet small enough for each MiniLED to serve as a single pixel. Therefore, MiniLED is primarily used as a backlight source for LCD panels.
MiniLED is not small enough for the ultimate display revolution. The technology pushing the industry forward is MicroLED. A single MicroLED measures approximately 0.01 mm, roughly 1/100th the size of a standard LED.
MicroLED addresses nearly all the limitations of LCD and OLED. First, it does not require a separate backlight layer; MicroLEDs are sufficiently small to form the display panel themselves. This allows MicroLED screens to be extremely thin—even thinner than OLED panels—effectively reducing device size and weight.
MicroOLED
MicroOLED, also known as silicon-based OLED (OLED on silicon), combines semiconductor technology with OLED technology. MicroOLED uses luminescent organic materials between two electrodes; when current passes through, it emits monochromatic light, which is then filtered to generate the desired colors. MicroOLED light modules are deposited onto a substrate, typically silicon, for the main MicroOLED displays. This approach retains OLED’s self-emission advantages while producing thinner, smaller panels with lower power consumption. With fast response times and high luminous efficiency, MicroOLED makes achieving high PPI (pixel density) more feasible.
MicroLED vs. MicroOLED
MicroLEDs are generally defined as LEDs smaller than 75 μm and do not use sapphire substrates. MicroLEDs employ specialized epitaxial growth techniques to integrate high-density, micro-sized LED arrays onto chips. Their applications are broad, ranging from wearables and head-mounted displays to AR/VR and phototherapy devices. Being made from inorganic materials, MicroLEDs offer higher brightness and greater stability than OLEDs. The current challenge lies in accurately transferring millions of tiny LEDs onto the backplane (mass transfer), as well as subsequent testing and packaging, investing cost very costly.
In contrast, MicroOLED pixel sizes are not necessarily limited to 75 μm. The OLED fabrication process determines the size of each pixel. MicroOLED primarily uses deposition technology, where controlling the precise and uniform deposition of organic materials—sensitive to oxygen and water—onto the substrate is critical. Deposition equipment is a key focus of the process.
