Optically Clear Adhesives Enabling Flexible and Foldable OLED Display Bonding
Dr. Chris Campbell
Adhesives Platform Manager
Optically clear adhesives (OCA) have been used for more than a decade to bond rigid LCD and AMOLED displays for consumer electronics applications, offering optical, mechanical and electrical performance benefits. The performance requirements of an OCA to bond cover window, touch sensors, and circular polarizers in a plastic OLED display to bent coverglass or a flexible, foldable OLED display are drastically different from a flat, rigid device. For plastic OLED to bent coverglass bonding, the adhesive needs to be strong enough to resist spring back of the flat plastic OLED devices. For flexible, foldable OLED displays, the neutral plane needs to be managed during folding keeping strain to a minimum in critical layers of the device (e.g. touch sensor, TFT, TFE), and the OCA cannot deform (or cause other layers to deform) during the folding process. Folding also brings challenges to touch sensors that can no longer use conventional passivation layers. As a result, the OCA will be responsible for preventing corrosion of touch sensor materials such as metal mesh(1), silver nanowire (2), carbon nanotube (3), and graphene (4).
The presentation will discuss OCA performance requirements, including high peel adhesion, for flexible plastic OLED bonding to rigid cover lenses. For a foldable OLED display, it is either desirable to have an adhesive that perfectly decouples the layers from each other in bending (e.g. a material with no modulus) to minimize strain on critical layers or have adhesives that can be used to tune the position(s) of the neutral plane(s) during the folding process. When the device is in a folded (e.g. closed) position, the adhesive should have minimal creep to avoid flow and a subsequent change in thickness in response to the strains in the folded position. Upon unfolding the device, no visible buckles or wrinkles should be apparent in the display and the adhesive should enable it to recover quickly to the unfolded position. Finally, all of these adhesive properties should remain constant over the operating temperatures and conditions of the device. These requirements on the adhesive define a soft elastic material that has good adhesion and a low glass transition temperature. For corrosion protection of touch sensor materials in flexible and foldable devices, low WVTR and/or UV blocking can be added as functionality to OCAs in these bonding applications.
Dr. Chris Campbell joined 3M in 2007, after obtaining his PhD in Chemical Engineering from Northwestern University. Chris started in the Corporate Research Materials Laboratory, working on structural adhesive technology development. In 2011, Chris joined the Electronics Markets Materials Division and subsequently the Display Materials and Systems Division as a Product Developer for eBonding liquid adhesives, and both liquid and film optically clear adhesives. Chris Campbell is currently the Adhesives Platform Manager in the Display Materials and Systems Division, leading a team of researchers and developers that create optical bonding solutions in consumer electronics and automotive display applications. Chris is the inventor on 9 patents and recipient of two 3M Corporate Circle of Technical Excellence and Innovation Awards. Outside of the lab, Chris enjoys spending time travelling with his family--including an eight-week adventure of his entire family living in Seoul, South Korea--and cooking.
Monday, May 14, 2018
Michael’s at Shoreline
2960 N Shoreline Blvd
Mountain View, CA
6 PM social hour
7 PM dinner
8 PM lecture
|Walk-in (not guaranteed)
Lecture-only is free.
We accept cash or checks at the door, or online payment via credit card. No-shows are responsible for full payment of registration fee.
Please register below or contact:
Deadline for registration:
11:59PM, Tuesday, May 8 for early registration discount.
5:00PM, Friday, May 11 for regular registration.
Seafood - Broiled salmon, lemon buerre blanc
Chicken - Breast of chicken, Cacciatore
Vegetarian - Eggplant parmesan
You should receive confirmation of your registration; if not, please contact us again.