Finalist of the Innovation Award Laser Technology 2016
UVblade - Flexible Display Manufacturing by the Meter
Photo: Dr. rer. nat. Ralph Delmdahl (Copyright: Ansgar Pudenz)
Dr. rer. nat. Ralph Delmdahl
Product Marketing Manager
Coherent LaserSystems GmbH & Co. KG
Göttingen, Germany
Members of the Project Team
Dr. rer. nat. Ralph Delmdahl, Coherent LaserSystems GmbH & Co. KG, Göttingen, D
(Team Representative)
Dipl.-Phys. Thorsten Geuking, Coherent LaserSystems GmbH & Co. KG, Göttingen, D
Dr. rer. nat. Sven Passinger, Coherent LaserSystems GmbH & Co. KG, Göttingen, D
Dipl.-Ing. Rainer Paetzel, Coherent LaserSystems GmbH & Co. KG, Göttingen, D
Dr.-Ing. Kai Schmidt, Coherent LaserSystems GmbH & Co. KG, Göttingen, D
Dipl.-Phys. Hans-Stephan Albrecht, Coherent LaserSystems GmbH & Co. KG, Göttingen, D
Abstract
Flexible displays are entering the market with increasing frequency. Featherweight
smartwatches boast high-resolution readouts in unique form factors. The smartphone
landscape is changing almost daily, as advancing technology combines even greater
functionality with fashion. TV screens continue to evolve as well, with curved formats
rapidly gaining market share. Additionally, the center consoles of automobiles are
undergoing fundamental changes. Manufacturers are swapping numerous mechanical
knobs, buttons, and switches for ergonomic multi-functional touch displays.
The spirit of innovation does not end with common smart devices. It is now conceivable
to have a display that unrolls much like a window shade! Indeed, it would seem that
given the insatiable consumer lust for novelty, the flexible display market is about to
transform from a niche market to mass deployment.
The paradox of flexible display production is that a rigid glass substrate, or carrier, is
required to support the thin film of the actual display during the manufacturing process.
Separating this glass carrier from the active display is the final step in a multi-step
production process (See Figure 3.) This separation step was a clear bottleneck in making
displays on a truly industrial scale, as methods for separation of the display from carrier
left much to be desired in terms of throughput, quality, and yield.
Enter UVBlade. The market introduction of UVblade laser system in 2013 solved the
dilemma of carrier separation, and paved the way for flexible display mass
manufacturing. Before the advent of the UVblade system, display manufacturers were
limited to costly, small-scale separation of flexible displays with limited capacity.
Alternative separation techniques are largely unsuitable for mass production. Chemical
etch processing is slow and not entirely specific, reducing yield. Alternative light-based
processes using frequency-doubled lasers could not provide enough light energy at the
appropriate wavelength.
With the UVblade system, Coherent has brought an excimer laser system to the market
that enables the cost-efficient volume production of the latest generation of flexible
displays, and it works for displays of all sizes. UVblade is the first and most advanced
laser lift-off system on the market capable of separating flexible displays from large
glass carriers at rate of hundreds per minute. Moreover, UVblade manages the balancing
act between economic production of flexible displays and the use of the existing
production infrastructure which is still based on rigid display glass panel handling.
The UVblade system provides a meter-long, thin blade of UV laser light that smoothly
separates a flexible polymer layer from the rigid glass carrier in the so-called laser liftoff (LLO) process. The separated display electronics layers reside thus on the lightweight
and flexible polymer film, resulting in a paper-thin, conformant display. A key advantage
of the UV wavelength of the UVblade is its exquisite selectivity. This process gently
releases even the most sensitive 4K resolution OLED displays with very high yield. The
process is not only selective, but also environmentally sustainable, and cost-effective.
The released glass carrier is recovered for the production of the next batch of flexible
displays.
Via laser lift-off processing with the UVblade, it is possible for the first time to migrate
display technology (LCDs, OLEDs, electrophoretic) to much thinner lightweight polymer
carriers which can adjust to the shape of a consumer device.
Areas of Application
UVblade enables high volume flexible display manufacturing. Industrial manufacturers
that produce displays will clearly benefit from the innovation. Primarily, these are
smartphone, and tablet and wearable display industries. In addition, the OLED-TV
industry as well as the automotive and aerospace industry will benefit from flexible
displays that can conform to non-planar shapes.
Technological Impact

Reduced manufacturing costs

Improved quality and yield

Enables new product features such as additional flexibility

Shorter time to market, because existing infrastructure can be used
Photos
Photo 1: UVblade Mass Production System
(Copyright: Coherent)
Photo 2:
Laser Lift-Off Processing
(Copyright: Coherent)
Photo 3:
Flexible Display Processing Steps (Copyright: Coherent)