RGB OLED deposition on a glass substrate
1,867 PPI achieved on VR/AR displays
100% reliance on Japan, large-area production possible without FMM


The displays of VR and AR devices are darker and less sharp than those of TVs and smartphones, causing a significant number of users to struggle with prolonged immersion.

To achieve vivid image quality, the pixel density, or PPI (Pixels Per Inch), must be increased to a level where individual pixels cannot be distinguished by human vision, and it must improve proportionally as the display is placed closer to the eye.

The Korea Institute of Industrial Technology (KITECH) announced on the 19th that it has developed a process technology capable of manufacturing OLED pixels for VR and AR using the RGB method on a glass substrate, and has succeeded in achieving a resolution of 1,867 PPI.

Generally, while 4K UHD TVs require 100 to 200 PPI and smartphones require 500 PPI, VR/AR devices worn close to the eyes must meet at least 1,800 PPI.

OLED pixels are manufactured by depositing organic materials at regular intervals on a substrate and are broadly classified into RGB and WOLED methods.

The RGB method, which deposits red, green, and blue organic materials in sequence, makes it difficult to develop processes for increasing pixel density compared to the WOLED method, which applies color filters to white OLEDs, but it offers superior brightness and power efficiency.

High-resolution display substrate materials for VR and AR are divided into glass and silicon wafers; while glass substrates are at a disadvantage compared to silicon wafer substrates for achieving high resolution, they are advantageous for manufacturing large displays due to their lower production costs.

A research team led by Dr. Kwan-Hyun Cho of the Micro-Nano Process Group developed a high-resolution OLED display manufacturing process suitable for VR and AR by leveraging the advantages of both RGB and glass substrate methods.

The core of this source technology lies in a special container composed of multiple microchannels that can hold the OLED solution at intervals of 13.6㎛ (micrometers), a selective surface treatment technique that causes the solution to adhere only within the channels, and a photothermal conversion layer that absorbs light and converts it into heat.

The principle is that a glass substrate is placed on a special container, and then a xenon flash lamp that emits a strong light instantaneously is activated underneath, causing the photothermal conversion layer inside the special container to rapidly vaporize the OLED solution with heat of over 300°C and deposit it onto the substrate at predetermined intervals.

The key advantage of this technology is that it enables the low-cost production of high-resolution OLED displays for VR and AR on glass substrates that can be scaled up. This facilitates mass production, and for users, it offers a wider viewing angle, enhancing immersion and alleviating dizziness.

In addition, since a photothermal conversion layer is utilized when depositing organic materials onto a substrate, there is no need to use a Fine-Metal Mask (FMM), which is an essential material for conventional RGB deposition processes. FMM, which is 100% exclusively produced in Japan, is a thin steel plate with densely packed fine holes that helps organic materials be deposited at specific locations on a substrate.

Dr. Cho Kwan-hyun said, “We were able to deposit RGB OLEDs on glass substrates under optimal conditions by leveraging our experience and know-how from previous photothermal conversion research,” adding, “We plan to increase the resolution to 2,000 to 3,000 PPI by utilizing microelectromechanical systems (MEMS) processes capable of producing devices several micrometers in size.”