Improving airtight bonding in OLED lighting

The UltraWELD project, which has been part-funded by Innovate UK, the UK’s innovation agency, will develop photonic-based processes for highly dissimilar material joining, a common technique used in the manufacturing of complex electro-optics.

Existing technology to join dissimilar materials is mainly focused upon adhesive bonding. While adhesive bonding is highly flexible and low cost, it cannot provide truly hermetic bonds, which leads to reduced performance or optical damage.

The project will focus primarily on the bonding of glass to metal, for example in the hermetic sealing of thin glass Organic Light Emitting Diode (OLED) devices and optical components for electro-optics, miniature lasers and sensors. CPI will use advanced equipment on glass up to 100μm thick to make OLED devices, which will be provided to a partner to carry out laser hermetic sealing. Using material combinations of crystal quartz to stainless steel and BK7 glass to aluminium, the improved bonding technique will have applications in defence and aerospace.

CPI’s in-house facilities and expertise across the manufacturing and testing of OLED devices will support the development of a laser prototype machine that will produce robust repeatable welds and deliver associated process monitoring and post process inspection. High repetition rate ultrafast lasers will also be used to achieve high precision laser welding in confined glass metal interfaces.

The 30 month project will additionally explore secondary benefits, such as airtight sealing for vacuum insulated glazing. This includes toughened safety glass on metal for lightweight vehicle windows, hermetic sealing of microfluidic devices and glass window bonding to silicon PV panels to protect against moisture.

Dr Sam Chan, CPI Senior Scientist and UltraWELD Project Manager, stated: “UltraWELD provides CPI an excellent opportunity to prove the manufacture of flexible glass OLEDs. Working with the project consortium enables laser hermetic sealing of OLEDs, a perfect protection against moisture, which can be used for all Optoelectronics devices and can enhance their lifetime. CPI will use gained know how in the manufacture of flex glass OLEDs to further build and disseminate UK-OLED manufacturing knowledge to our partners in the High Value Manufacturing Catapult and their customers.”

Oxford Lasers will both coordinate the programme and build a laser prototype machine to demonstrate new developments based on advanced ultrafast laser micro-joining of highly dissimilar materials.

Oxford Lasers’ Project Manager, Dr Dimitris Karnakis, added: “This is a first-class opportunity to work with a top team of UK experts in leading industrial and academic organisations and establish presence in a growing new laser niche. We expect to be able to offer customised laser micro-joining systems and subcontract services to the defence and aerospace and thin glass OLED sectors by 2020. We will also extend our reach to other application areas with some synergy such as photonics, microfluidics, solar PV and glass microprocessing technology, which are well aligned to benefit from our microwelding advances.”

Dr Peter MacKay, Principal Technologist for Gooch and Housego UK, finished: “The consortium is tackling the issue of outgassing of epoxies generally used in optical assemblies by providing a completely new bonding technology. This will enable Gooch and Housego to supply mounted optical components to applications such as high power laser systems and UV systems, where contamination and damage caused by outgassing is a significant issue.”