Seoul Semiconductor Ends Need for Rare Earths in White LEDs

Affiliate Seoul Viosys begins mass production of WICOP 3, which emits white light without rare earths from chips as small as 10 micrometers

For three decades, white LEDs have depended on rare earth materials such as yttrium aluminum garnet (YAG) layered onto a blue LED chip (Figure 1). Seoul Viosys Co., Ltd. (KOSDAQ: 092190) today announced that it has broken that dependence. It has developed and begun mass producing a chip that emits white light without rare earths. The chip can be as small as 10 micrometers (µm).

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Figure 1. New invention: white WICOP 3 (source: Seoul Semiconductor Co., Ltd.)

Seoul Viosys and its parent company Seoul Semiconductor Co., Ltd. (KOSDAQ: 046890) opened the micro LED market with WICOP. WICOP is a chip architecture that eliminates the package altogether. Doing away with the package is widely regarded in the industry as a revolution in six decades of semiconductor history. With WICOP, the two companies have already developed and mass produced ultraviolet, blue, green, red and infrared LEDs under 100 µm that are too small for the eye to see. WICOP 3 is the third generation of the technology. It now extends that capability to white light without rare earth elements (REEs).

Economic Impact

1) The White LED Market

White LEDs make up roughly $10 billion of the $15 billion global market for packaged LEDs. WICOP 3 can now replace them with a technology free of rare earths.

More significant still, WICOP 3 is the world's first white opto-semiconductor to achieve white light in a micro LED smaller than 100 µm. At that size, it is invisible to the naked eye.

WICOP 3 uses neither rare earths nor package. Rare earths are a major source of environmental pollution, and WICOP 3 contains none. It nor does contain the synthetic silicone resins, plastics and lead frames used in conventional LEDs. The result is a far more environmentally friendly product that costs about half as much to make as a conventional white LED.

2) Creating New Markets

The miniaturized transistor replaced the vacuum tube and created vast new markets in electronics. The company believes micro white opto-semiconductors can do the same. WICOP 3 generates white light from gallium nitride (GaN) alone. GaN is a natural material, and the chip contains no plastics, silicone or other synthetic organic materials. As a result, it is virtually permanent and can last for decades. In lighting, invisible micro opto-semiconductors could be embedded in wallpaper or window glass. They could light a space with no fixtures at all. This would end the inconvenience of replacing bulbs and the high cost of fixtures. The company expects this to create a new market tens of times larger than today's $10 billion white LED market.

Performance

In its first mass production, a micro LED chip measuring just 25 µm by 10 µm produced 0.015 lumens of white light. Its chromaticity falls inside the CIE standard white region (Figure 2). Luminous efficacy is already close to 100 lumens per watt (lm/W). The company aims to reach 200 lm/W within two years. A conventional 1,000 µm by 1,000 µm chip achieves 50 lumens.

Technical Significance

Until now, WICOP could make chips smaller, but white light still required a package containing rare earths. White chips therefore could not go below 1,000 µm. This held back cost reduction. White micro LEDs under 100 µm (0.1 mm) were also out of reach. Removing rare earths changes that. White light is now possible both in large chips of 1,000 µm and above and in micro LEDs below 100 µm.

The company compares this advance to 1948. That year, Bell Laboratories in the United States moved electronics from the vacuum tube to the transistor. Seoul Semiconductor and Seoul Viosys have likewise moved beyond LEDs made to be seen. They have invented chips too small to see that emit red, green, blue, infrared, ultraviolet and now white light. The shift opens a broader era for opto-semiconductors that spans AR and AI communications.

Some products marketed as “flip chip” LEDs replicate WICOP's patented technology. Seoul Semiconductor continues to protect its intellectual property worldwide.

Development Background and Evolution

Since the 2010s, more than 10 major Korean groups and over 300 Chinese companies have entered the LED market. Price competition grew ever fiercer. Founder Chung Hoon Lee, who studied physics concluded that the company needed strategic, breakthrough technology to survive and grow. It has since invested about $100 million a year in R&D and new inventions, even in years when the business was not profitable. Silicon and opto-semiconductors are both made of soft materials that are vulnerable to dust and moisture. For that reason, both have been packaged for 60 years.

1) WICOP (First Generation)

WICOP began with a simple question Lee asked one night: “Why do semiconductors have to be packaged?” After years of research, Seoul Semiconductor developed WICOP in 2018 and brought it into high volume production. It was the first chip in semiconductor history that needs no package. Silicon semiconductors evolved from vacuum tubes to transistors and then to integrated circuits holding tens or hundreds of transistors. The company was convinced that WICOP could lead a similar evolution in opto-semiconductors and make invisible micro LEDs below 100 µm possible. The company has also conducted joint R&D with the University of California, Santa Barbara (UCSB) for 20 years. This work has produced devices on the 1 µm scale.

2) WICOP 2 (Second Generation)

LEDs once needed a lens to control the direction of their light. Lee questioned that too: “Why must we use a lens?” He also asked, “Why must semiconductors operate only at 3 volts when household power is 110 or 220 volts?” The answers produced WICOP 2. It directs light without a lens and operates at higher voltages, of 12 or 24 volts. Electric and hybrid vehicles run on high voltage batteries. In these vehicles, high voltage opto-semiconductors can cut power consumption by 20%. WICOP 2 is now supplied to global customers including Tesla.

3) WICOP 3 (Third Generation)

The third generation grew from the question “Why must white light require rare earths?” “We have now successfully developed WICOP 3, which produces white light, and have begun mass production,” said Lee, founder of Seoul Semiconductor.

Future Plans

Seoul Group comprises Seoul Semiconductor and Seoul Viosys. The group will start mass production of WICOP 3 in the fourth quarter. It will supply first those customers that have respected its intellectual property and relied on its products. WICOP 3 makes white light without rare earths. It is also the ultimate white light source: semipermanent even at invisible sizes of 100 µm or less. Even so, the group will hold to its “Keeping Principle” of never competing with its customers. It will instead open new application markets together with its key customers.

Seeking Supply Chain Partners

Seoul Viosys is an affiliate of Seoul Semiconductor. It uses WICOP to produce micro opto-semiconductors below 100 µm. Micro LEDs built on WICOP can now carry high volumes of AI data over distances from under 1 cm to tens of meters. Over short distances, data has long traveled through copper wire as electrons. Electrons have mass. Under the data loads of the AI era, copper links slow down, generate heat and consume sharply more power. The company instead sends data as light. Photons have no mass. It arranges 1,000 WICOP chips of about 10 µm each in a grid within 1 square millimeter or less (Figure 5). This array transmits data 10 times faster at one tenth of the power. Market research firms including Omdia forecast that this technology and AR together will create a new $60 billion market within five years. That is equal to half of today's DRAM memory market.

Lee said the company intends to use WICOP 1, 2 and 3 to help people around the world live better lives through AR glasses and AI data communications. These technologies work at invisible sizes of 10 µm or less. To that end, it is seeking trusted upstream and downstream micro LED supply chain partners in AR displays and AI transmitters to build the new $60 billion market together.

About Seoul Semiconductor

Seoul Semiconductor is a global LED company. Holding more than 15,000 patents and backed by a differentiated product portfolio, the company researches, develops, and mass-produces LED products for every application—including indoor and outdoor lighting, automotive, IT (mobile phones, computers, etc.), and ultraviolet (UV) and supplies them to customers worldwide. Its world-first products have become standards in the LED industry, and innovative products such as WICOP, a package-free LED; Acrich, an AC and high-voltage LED; nPola, more than 10 times brighter than conventional LEDs; Violeds, a cutting-edge UV sterilization technology; filament LED technology that emits light in all directions; and SunLike, a natural-spectrum LED, are leading the global market. For more information, visit the company website (http://www.seoulsemicon.com/) and its social media channels (YouTube, LinkedIn).

About Seoul Viosys

Seoul Viosys has the technological capability to produce optical semiconductor chips across the full wavelength range from 200 nm to 1,400 nm, backed by 6,000 patents, and can also manufacture VCSELs (Vertical Cavity Surface Emitting Lasers) and laser diodes. The company also mass-produces WICOP Pixel, the world's first chip to integrate R, G, and B for displays in a single chip. Founded in 2002, Seoul Viosys currently holds the world's No. 1 market share in UV LEDs and, in collaboration with its parent company Seoul Semiconductor, which holds 15,000 patents, has secured a technological lead in the global market. For more information, visit the company website (www.seoulviosys.com).

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