Prof. Byeong-Soo Bae is from Solip Tech which is a spin-out from Kaist in Korea and was set up to exploit and develop a patented epoxy siloxane flexible hard coating materials for flexible displays. It then got VC funding.
There is a lot of interest in foldable and flexible displays, he said, but you need a plastic film with a hard surface coating and a PI film for the substrate. It’s hard to combine a hard coating with flexibility. Out-folding is more difficult than in-folding, in his view. As other speakers had said, thickness a key issue – thinner substrates are better. You really need something ‘paper-like’ – less than 200 um thick.
You need glass-like high strength, plastic-like low modulus and rubber-like elasticity and these are all very different, so it’s almost impossible to get all those properties in one material, especially as you also need 95% transparency and there are tough requirements in colour and haze. You need a kind of combination of the inorganic glass with a plastic in a hybrid. However, if you do this, you need a thick coating, which is a problem because you get a lot of warping during curing.
Conventional hard coatings are not possible to use, because of different kinds of stress. So the company uses sol-gel Siloxane hybrids which can be formed in many ways and are UV curable, The company performs a number of processes to create the film and has developed the Flex9H material which resists impact and combines glass like strength with plastic-like flexibility.
Hardness depends on the coating thickness and at 50um, the new film can get to 9H hardness. It can also be made in air which is a big advantage.
Soliptech can make hybrid films with glass fabric reinforced with embedded material (with a matched optical index) which it calls ClearFRP and this material can be made with a film lift-off process. It can be used in display cover applications such as 3D curved covers.
Adding the Flex9H layer to the ClearFRP, you can get glass-like scratch resistance, he said and you can also add an anti-glare treatment. The company calls this Stingray film. The combination can be moulded in 3D to make an unbreakable clear plastice with cratch resistance like glass which makes it good for tablets, phones and even automotive displays.
Analyst Comment
The lack of films that can protect flexible OLEDs from damage has been a major barrier to commercialisation of products and this solution looks, on the face of it, to be a very good one. If the company can do what it says that it can, it could be very successful. (BR)
