[News Terms] Stretchable Display That Stretches Like Rubber

Next-generation 'Stretchable Display' unveiled by LG Display on the 8th / Photo by LG Display Official Website Capture

Imagine a display that can be folded, twisted, or even stretched like rubber. The potential applications for electronic devices would be virtually limitless. This is the story of the next-generation technology in the display industry known as the "stretchable display." Leading countries in the industry such as Korea, Japan, and China are already engaged in a silent war competing for the title of the "first country to develop stretchable displays."

Today, "flexible displays" that can be folded horizontally and vertically have already been introduced in the latest smartphones. Samsung Electronics' Galaxy Fold and Flip are prime examples. However, stretchable displays possess a level of flexibility beyond that. They function perfectly even when bent, folded, twisted, or stretched.

If stretchable displays are mass-produced, the range of possible applications is nearly infinite. They can be used as bio-sensors attached to a patient's skin to monitor internal health in real time, or even embedded into textiles to create "smart fabrics." Essentially, they enable the electrification of virtually all consumer goods we use.

The Three-Way Race Among Korea, Japan, and China Surrounding Stretchable Commercialization

Recognizing the potential of stretchable displays, the three major players in the display industry?Korea, Japan, and China?have long been engaged in prototype development. In 2017, Samsung Display opened the competition by unveiling a 9.1-inch OLED stretchable display at the Society for Information Display (SID) conference.

Stretchable display with a thickness of about 1mm released by the University of Tokyo in 2018 / Photo by University of Tokyo website capture

The following year, researchers at the University of Tokyo in Japan attracted attention by developing a stretchable display called "skin electronics" with a thickness of only 1mm. This display is extremely thin and elastic, making it suitable for attachment to human skin without discomfort. China’s BOE, which has secured the largest share of the low-cost LCD (Liquid Crystal Display) market and ranks among the world’s largest display manufacturers, also unveiled a stretchable product named "Kirigami" last year.

As competition intensified, Korea’s Ministry of Trade, Industry and Energy began promoting stretchable display development as a national project in 2019, selecting LG Display as the lead organization. After three years of research, LG unveiled the world’s first high-resolution stretchable screen on the 8th. While previous stretchable displays developed by other companies only displayed simple numbers or patterns, LG’s display demonstrated performance close to that of a general household monitor, marking a significant milestone.

The Core of Stretchable Displays is 'Micro LED'... Yield Stabilization is Essential

However, there is still a long way to go before stretchable displays become practical. This is because stretchable displays use components that are much more difficult to mass-produce than conventional displays.

The reason flexible displays, which can be bent or folded, became feasible was due to advancements in next-generation components that make up the display, specifically LED (Light Emitting Diode) technology. Domestic display companies such as Samsung and LG have developed mini LEDs with horizontal and vertical dimensions of only 500 micrometers (?m, one-millionth of a meter). These mini LEDs are integrated into highly elastic special plastics to create flexible displays.

Stretchable displays take this a step further. The LEDs used in stretchable displays are advanced components called "micro LEDs," which measure only about 10 to 50 ?m in horizontal and vertical dimensions, making them much smaller than mini LEDs. By densely arranging these micro LEDs on highly elastic materials, stretchable displays can be created.

Sapphire, known as the mineral with the second highest hardness after diamond, is difficult to process in microfabrication. This is also the reason why the price of micro LEDs is high. The photo shows a sapphire ingot, the raw material for sapphire wafers. Photo by Korea Information Display Society website capture

Unlike conventional semiconductors made from silicon materials, micro LEDs are manufactured based on sapphire wafers. Sapphire is known as the second hardest material after diamond, making nanometer (nm) scale processing extremely challenging. For this reason, micro LED prices are prohibitively expensive for commercialization. For example, when Samsung Electronics first launched its "110-inch micro LED TV" last year, the consumer price was a staggering 170 million KRW (approximately $140,000).

Samsung's 110-inch Micro LED TV / Photo by Yonhap News

In other words, the commercialization potential of stretchable displays depends on whether Samsung, LG, and others can stabilize the yield of micro LEDs and reduce component costs. Currently, these two companies plan to increase demand by first launching micro LED products in the premium TV market. Samsung recently received radio certification for its 89-inch and 101-inch micro LED TV models for home use, and LG also completed radio conformity evaluation certification registration for its ultra-large 136-inch micro LED TV on the 3rd of last month.

Market research firm TrendForce forecasts that although the micro LED market size is only $54 million (approximately 74.4 billion KRW) this year, it will grow at an annual rate of 204%, expanding to $4.5 billion (approximately 6.2 trillion KRW) by 2026.