KRISS commercializes an interferometric sensor to detect defective glasses | Research Highlights | News & Resources : 한국표준과학연구원 영문

KRISS commercializes an interferometric sensor to detect defective glasses

• Writerkrissadmin
• Date2018-07-11 00:00
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KRISS commercializes an interferometric sensor to detect defective glasses

- Development of a sensor for measuring thickness and refractive index of large glass panels -

# Flat-panel displays sold in the Republic of Korea have grown by an average of 10 inches over the past seven years. As manufacturing process becomes more complicated along with unexpected variables, it is quite difficult to maintain low level of a defect rate of large glass panels. For this reason, strict inspection is required during the whole manufacturing processes.

Korea Research Institute of Standards and Science (KRISS, President Sang-Ryoul Park) developed a robust technology detecting defects of large glass panels, and then has commercialized a thickness measuring sensor successfully by transferring the technology to a company specializing in optical inspection.

A team led by Jonghan Jin, principal scientist of the Center for Optical Metrology at KRISS, developed a sensor capable of measuring physical thickness and refractive index of large glass substrates in real-time, even under the strong vibration conditions.

As customers prefer ultra-large screens of their flat-panel displays, the demand on large bare glasses has been increasing, which leads the expansion of the related market. Owing to size of the large bare glasses over several meters, the production of the glasses having uniform thickness is not an easy work. Irregular form of the glasses caused by thickness variation may damage image pixels and distort images.

Under harsh environmental conditions with strong vibration, however, conventional inspection machines have been rarely worked in production lines.

The team led by Dr. Jin developed a sensor capable of measuring physical thickness and refractive index of large glass substrates in real-time, which works based on optical interferometry. With the adoption of transmissive configuration, the sensor achieves the world’s best technical performance in terms of vibration insensitivity without degradation of measurement accuracy.

Another novelty of this developed technology is to measure the refractive index of bare glasses. Since optical interferometers provides only optical thickness, the conventional interferometric techniques need to know the refractive index in advance to extract the physical thickness from the optical thickness. On the other hands, the newly developed sensor can measure physical thickness and refractive index at the same time.

Dr. Jin said, “The measurement technology is optimized to apply for the manufacturing process of glass substrates being used in a wide range of IoT-based products. We have realized simultaneous measurements of physical thickness and refractive index under strong vibration conditions, which is not possible with other conventional sensors.”

In 2017, KRISS transferred the technology to Novitec specializing in optical inspection. Novitec has succeeded in commercialization, and signed a product supply agreement with a global glass manufacturer in July 2018.

Junyoung Lee, the CEO of Novitec, said, “We have developed an outstanding product thanks to technology developed by KRISS, and supplied it to a global company. We are planing to expand our business territories and go into global markets, not only for glass substrates, but also solar panels and silicon wafers.”

▲ A sensor capable of measuring physical thickness and refractive index of large glass substrates at real-time, which is commercialized based on measurement technology developed by KRISS.

▲ Jonghan Jin (principal scientist, far right) and his team measures the physical thickness and refractive index of a large glass panel.