Starting date : Jan 2017 > May2020
Lifetime: 36 months
Program in support :
Status of project : complete
CEA-Leti's contact :
> Etienne Quesnel
Project Coordinator: CEA-Leti (FR)
Partners: - CH: Novagan
- FR: CEA-Leti, Microoled, Nexdot
Investment: € 4.1 mi
EC Contribution: € 4.1 mi
| Stakes
- At the project halfway point, progress has been good in relation to most of the technologies required for manufacturing LED microdisplays.
- Fully optimized, blue LED epilayers have been grown by Novagan to provide a 10μm-pitch matrix using micro-LEDs exhibiting an external quantum efficiency that exceeds 9% at 3V and an emission wavelength variation reduced by a factor of 3 (±4 nm). Both these performance characteristics are closely in line with application requirements for reaching the expected brightness of 1Mcd/m2.
- While more complex than expected, the CEA-Leti-developed architecture of the CMOS backplane circuit is now ready for building the tape-out circuit.
- Coupling of the LED and CMOS has been demonstrated on the CEA-Leti technological platform. As a proof of concept, the Novagan-supplied GaN epilayer has been transferred to an 8’’ Si wafer and 8μm pixel/10μm pitch LED arrays have been successfully processed.
- Different light conversion strategies have been assessed, paving the way to efficient light converters:
◾2D conversion layers: blue-to-green conversion layers based on InGaN/GaN Quantum Wells(30 x QW) have been grown on sapphire substrates by Novagan. Blue absorption of 1 % per QW means that light trapping architecture will be required at pixel level. Similarly, AlInGaP QW, blue-to-red conversion layers have been successfully transferred to sapphire substrates. While optical measurements on a CEA-Leti dedicated optical bench have indicated blue-to-red down conversion, the observed strong light guiding effect suggests dedicated light extraction structures to be implemented at pixel level (under investigation at CEA-Leti).
◾Quantum dots: as an alternative approach, photo-patterned resin layers containing 2D nanoplatelets (NPL) has also been considered. More absorbent, stable core-shell NPLs have been successfully synthesized at NEXDOT and first photo-patterning of red NPL/resist composite has been demonstrated on the CEA technological platform with pixel pitch resolution down to 10μm.
- There is growing market demand for high quality information displays in multiple application fields. This is particularly true in commercial avionics, in which high luminance displays capable of displaying readable information in a very bright environment are required.
- Today’s technologies do not permit manufacturing of compact displays of the required brightness combined with very low power consumption.
- The purpose of the HILICO project is to develop a new generation of monochrome and full color emissive GaN micro-displays offering 1920 x 1200 pixel resolution (WUXGA), 8-μm pixel pitch, very high brightness (> 1MCd/cm²) and good form factor capabilities for designing a ground-breaking, compact, see-through system for next generation avionics applications. The project is taking up the following challenges:
- Development of high-quality, GaN-based, LED epilayers designed to fulfill targeted demonstrator performance characteristics
- Design and fabrication of an active matrix based on advanced, complementary, metal oxide semi-conductor (CMOS) technology to control each pixel
- Coupling of the LED structure and the CMOS to build a monolithic structure, on which high-precision LED arrays can be manufactured to build monochrome, active matrix, high-resolution GaN microdisplays
- Addition of color converters (quantum dots and 2D Multi-Quantum Wells layers) on blue emitting devices for manufacturing bi-color and full-color display demonstrators
- Design and manufacturing of the electronics followed by testing and assessment of the completed microdisplay device. First demonstrators will be qualified for future commercialization.The project consortium brings together an RTO, a major manufacturer and two SMEs. It has received a grant of 4,091,583 > with an effort of 283 person-months (PM).
IMACT
- The technology developed within the HILICO project is contributing togreater European competitiveness through rapid, massive deployment of innovative products on the microdisplay market along with head-up displays, head-mounted displays and smart eyewear devices.
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