OLEDs: Success in smartphone and TV displays is a precursor for the entire display industry

01 July 2021
By Barry Young
LG rollable TV
LG’s rollable TV. Credit: LG

Organic light-emitting diodes (OLEDs) are monolithic, solid-state devices that consist of a series of organic thin films sandwiched between two thin-film conductive electrodes. When electricity is applied to an OLED, under the influence of an electrical field, charge carriers (holes and electrons) migrate from the electrodes into the organic thin films until they recombine in the emissive zone forming excitons. Once formed, these excitons, or excited states, relax to a lower energy level by giving off light (electroluminescence) and/or unwanted heat.

The basic OLED cell structure consists of a stack of thin organic layers sandwiched between a conducting anode and a conducting cathode. They are manufactured by depositing the chemicals on a glass substrate between an anode and cathode by using vacuum thermal evaporation or inkjet printing depending on whether the chemicals are in a solid or soluble form. The current is provided by an active matrix using either low-temperature polysilicon, indium gallium zinc oxide, or a combination of the two.

Compared to LCDs, OLED displays are thinner, have higher contrast, faster response time, wider viewing angles, more accurate color representation, and weigh less. Depending on the application, OLED panel prices may be the same as an LCD or be more expensive. While LCD displays must keep the backlight on all the time, OLEDs power subpixels independently, so the display only uses power when a subpixel needs to be lit. Most videos average around 20 percent of the pixels on, so for TVs, OLEDs use less power than LCDs. A similar construct exists for smartphones. But monitors and notebooks use office applications, which are heavily tilted to white space, where OLEDs tend to use more power than LCDs, which is why OLEDs have low penetration in those markets.

OLED panel shipments by application

OLED panel shipments by application. Credit: UBI Research

Samsung Display has been the dominant supplier of small/medium displays and enjoys a 70 percent market share. The Chinese display makers—BOE, CSoT, Tianma, Visionox, and EverDisplay—have almost as much capacity as Samsung, but they have struggled with yields and quality. However, in 2020 they crossed the performance threshold and are expected to ship more than 100 million displays in 2021. Recently, BOE qualified to be a supplier to both Samsung Mobile and Apple. LG Display is the only panel maker producing TV-size displays, but they will be joined by Samsung, CSoT, and BOE over the next three years.

In 2020, OLED displays were used in smartphones, TVs, smartwatches, notebooks/tablets, and automotive monitors. But smartphones make up 80 percent of the OLED display revenue. Total panel shipments were 800 million, up 18 percent year-over-year, despite the pandemic. In 2021, growth is projected to be 21 percent.

Revenues rose steadily from $9.5 billion in 2015 to $31.8 billion in 2020. As the shipment volume grows, so will the revenues, which are forecast to hit $40 billion by 2022—a 33 percent share of the total display market.

OLED panel revenue

OLED panel revenue. Credit: UBI Research

OLEDs are also used in microdisplays for headset applications like night vision, fighter pilot headsets, and augmented reality. They can be produced with fields of view of over 100 degrees and produce luminance levels of 7,000 cd/m2. However, the luminance levels will have to grow to 30,000 cd/m2 to provide sufficient light in high ambient conditions, given the need to offset light losses from the required lens, color filters, or circular polarizers.

OLED technology is constrained by the lifetime of the organic material and therefore has limits in terms of luminance. The harder the device is driven, the shorter the lifetime. The lifetime issue is most significant for TVs, where the current luminance is on average 800 cd/m2 and 1,000 cd/m2 peak, with lifetimes of 50,000 hours. Much effort is going into making the material more efficient in order to increase lifetimes and peak luminance. High-end smartphones have peak luminance in high ambient conditions of over 1,500 cd/m2 in order to make them sunlight readable.

Huawei’s foldable Mate X2 smartphone

Huawei's foldable Mate X2 smartphone. Credit: Huawei

OLEDs are unique in that they can be folded or rolled to give product designers wide choices in form factor. A new range of products have been developed based on OLED displays, including folded and rolled smartphones that also serve as tablets; folded laptops, where one display can serve the dual purpose of a display or a keyboard; and TVs that fit in a small container when not used, and then roll out into a 65-inch display when needed.

In addition to foldable and rollable architecture, OLEDs offer a range of new design features, such as transparency that allows viewers to see through the display at up to 50 percent visibility; cameras placed under the display to eliminate the notch and still preserve the ability to take selfies; the use of ultra-thin glass (<100 µm) that serves as both a barrier and cover lens; and under-panel fingerprint readers to minimize the display thickness.

In the coming years, OLED technology is expected to advance by adding a more efficient blue emitter, which would improve efficiency (which means battery life) by 25 percent, eliminate components, and improve lifetime. Moreover, JOLED in Japan has developed a mass-production process that inkjet prints the organic layers, reducing the material costs by approximately 10 percent, because it is more than twice as efficient as VTE in terms of material utilization. TCL, the second-largest global panel maker, is investing approximately $5 billion to build a Generation 8.5 OLED fab to enter the TV market using this technology.

The curved 38-inch OLED display on the 2021 Cadillac Escalade

The curved 38-inch OLED display on the 2021 Cadillac Escalade. Credit: Cadillac

OLEDs are the first technology to challenge LCDs in over 30 years and have taken more than 25 percent share of the revenue. The improvements being made to OLED technology in terms of cost reduction, efficiency improvements, and higher luminance should drive market share to more than 33 percent by 2025 and 50 percent before the end of the decade. Moreover, display capital expenditures are predominantly for OLEDs, meaning the capacity will grow, while LCD capacity remains flat or goes down. The threat to OLEDs beyond 2025 is MicroLEDs, which promise to outperform OLEDs, but have unsolved technical challenges that contribute to costs two to four times that of OLED panels.

Barry Young is CEO of the OLED Association, LLC a nonprofit that supports the OLED industry. Previously, he was a cofounder, senior analyst, and CFO of DisplaySearch.

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