Printed Assemblies of Ultrathin, Micro-scale Inorganic Light Emitting Diodes for Deformable and Semitransparent Displays
Display devices represent ubiquitous, central components of nearly all consumer electronics technologies. Organic light emitting diodes (OLEDs) are rapidly emerging as an attractive alternative to backlit liquid crystals due to their comparatively high refresh rates, contrast ratios, power efficiencies and capacity for vibrant color rendering. Inorganic light emitting diodes (iLEDs) can also form displays, with properties such as brightness, lifetime and efficiency that can exceed those possible with OLEDs. Presently, however, these displays exist only in ultra-large area, low resolution formats (square meters; billboard displays), limited by processing and assembly procedures that do not scale effectively to small (< ~200x200 µm), thin (< ~200 µm) light emitters or to dense, high pixel count arrays.
This technology presents routes to create ultrathin (~2.5 µm; thinner possible), ultra-small (down to ~25x25 µm; smaller possible) iLEDs, in flat or ‘wavy’ geometries and to assemble them into large scale, addressable arrays using scalable processing techniques, on substrates ranging from glass to plastic and rubber.
Description/Details
This technology develops methods for creating ultrathin, micro-scale, inorganic light emitting diodes (LEDs) and for assembling and interconnecting them into unusual display and lighting systems. The LEDs use specialized epitaxial stacks designed to allow delineation and release, by controlled etching processes on a growth wafer, of large collections of ultrathin devices in diverse shapes with dimensions from microns to millimeters, in either flat or ‘wavy’ configurations. Printing based assembly methods can deliver these devices to substrates ranging from plates of glass to sheets of plastic or slabs of rubber, in arbitrary spatial layouts and over areas that can be much larger than those of the source wafer. The geometries of these LEDs enable them to be interconnected for direct or matrix addressing by use of conventional planar processing techniques. Displays, lighting elements and related systems formed in this manner can offer mechanical (e.g. flexibility, stretch-ability) and optical (e.g. semi-transparency, bidirectional emission) properties that might create new, important application opportunities for inorganic LEDs.
Applications
- Large area displays
- Illumination (Indoor and Outdoor lighting)
- Desktop monitors
- Home theatre systems
- Instrumentation gauging
- Wearable health monitors & diagnostics
- Biomedical imaging devices
- Vehicle navigation
- Heads-up displays
Benefits
These devices can be control etched in diverse shapes, either in flat or ‘wavy’ configurations, they can be ‘printed’ on a variety of substrates ranging from glass to plastic and rubber and they can be interconnected for direct or matrix addressing by use of conventional planar processing techniques
These features enable fabrication of displays, lighting elements and related systems that can offer mechanical (e.g. flexibility, stretch-ability) in form factors not previously possible and optical (e.g. semi-transparency, bidirectional emission) properties
The fabrication process of the displays becomes much cheaper than the existing processes and reduces energy consumption.