LG Innotek, Korea’s first electronic components company founded in 1970, has grown into a leading global materials and components company by intensively fostering world- class products through continuous technological development and process innovation.
LG Innotek Announced on February 15th that the company has begun to strengthen its market penetration by introducing “2-Metal COF”, an essential product for XR equipment, and launched the product at the International Consumer Electronics Show ( CES).
COF (Chip on Film) is a semiconductor package substrate that connects the display and the main printed circuit board. It helps minimize display bezels and miniaturizes modules in electronic devices such as TVs, laptops, monitors and smartphones. Since microcircuits must be formed on very thin films, requiring a high level of technology, it is also known as an ultra-fine flexible circuit board, which can replace the existing flexible printed circuit board (FPCB).
COF can only form circuits on one side of the film, while “2-Metal COF” forms a large number of fine circuits on both sides of the film and allows electrical signals to travel faster between devices, thereby supporting its high-definition processing screen image.
According to LG Innotek, the product has a via hole size of 25μm. Considering that the thickness of human hair is 100 μm, the through hole is about a quarter of the thickness of a human hair. The smaller the via hole, the more channels connecting the upper and lower surfaces of the product, and the more graphic circuits through which the electrical signal passes.
Recently, with the official beginning of the metaverse era, the demand for bendable or foldable displays has increased, and the demand for flexibility of components mounted on them has increased, which is why “2-Metal COF” that can be bent freely is considered to be one of the products that fits the current display industry trend.
Improve user immersion by supporting high-resolution displays
LG Innotek’s “2-Metal COF” can form more than 4,000 circuits on both sides by combining thin films. Generally speaking, the more pattern circuits, the better the pixels. If pixels are improved, it will be possible to create XR devices that offer a high degree of immersion. If the virtual image displayed through the XR device has a low resolution, it will appear like viewing the image through a mosquito net (screen door effect). LG Innotek has continuously improved the specifications of “2-metal COF” since 2016 to minimize the screen door effect and support ultra-high resolution.
In particular, LG Innotek reduced the width of the pattern circuit to a pitch of 16μm by adopting a new process method. The width of the pattern circuit was reduced to the narrowest level in the industry from the original 18μm. As the circuit width decreases, the number of patterned circuits that can be accommodated on the COF surface increases, so users can see images with better quality even on the same size display.
In fact, IT manufacturers are increasingly adopting high-quality displays with minimal bezels to demonstrate the competitiveness of their devices. Manufacturers used to use chip-on-glass (COG), the technology behind display drives. COG is a technology that places a chip on top of a display, but since it cannot be expected to be flexible, it does not meet the current trend of “bezel-less” and “flexible” in the display industry. Therefore, “2-Metal COF” that stably supports high pixel count while shrinking the display frame is attracting attention.
Thin and flexible, free design
LG Innotek’s “2-Metal COF” is a thin and flexible film type that can be folded or rolled freely. In addition, it bends more smoothly than conventional COFs, and the film thickness is only 70 μm, the thinnest among semiconductor substrates. Usually, the thickness of the substrate for semiconductor packaging is 150 μm or more. As a result, the installation space for parts can be reduced, and the assembly company can secure space for placing more parts. It can even help design further optimizations for XR devices.
Reducing the thickness helps to improve the flexibility and thinness of the finished product, which has the advantage of increasing the design freedom of the display panel manufacturer. Regular consumers will also be able to encounter products that are more fully designed than existing XR devices.
2-Metal COF ushers in the XR era with wide applications
LG Innotek is focusing on technology upgrades to widen the gap with competitors, while launching aggressive promotions targeting North America and Japan, where there are many XR device makers.
The high-density circuit realization technology of “2-Metal COF” is applied as an alternative technology for products that are difficult to handle with flexible circuit boards, and it is also being developed and applied to new products such as Micro LED.
“LG Innotek will lead the ‘2-Metal COF’ market based on the technical strength and quality that has led the substrate business for 50 years, and will create differentiated customer value through products suitable for various applications,” said the director of the substrate material business department.