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Large Organic Robust Imager for X-ray sensing

Periodic Reporting for period 3 - LORIX (Large Organic Robust Imager for X-ray sensing)

Reporting period: 2017-02-01 to 2018-07-31

Just like for visible image sensors, the global trend in the X-Ray image sensor market is to move from analog (silver films and semi-digital computed radiography (CR)) to digital direct radiography using flat panel detectors (FPD). Even if advantages like lower operational cost, higher performance and higher throughput are obvious, transition from analog to digital remains nevertheless limited for X-ray portable applications in medical diagnosis & industrial inspection, in particular because of the cost of system ownership and a lesser mechanical reliability, especially with regards to falls & shocks (compared to film & CR). By addressing both of these drawbacks, LORIX’s ambition is to speed up FPD market penetration and to strengthen European industries’ leadership position in the X-Ray imaging market.

LORIX aims to develop, prototype and demonstrate large area X-ray detectors enabled by TOLAE (Thin Organic and Large Area Electronic) technology by combining printed Organic Photo Diodes (OPD) with existing active matrices Thin Film Transistors (TFT) arrays on glass or on plastic foil (organic TFT solution), depending on the targeted application. Within the project, three different applications are covered: medical imaging (e.g; medical general radiography, fluoroscopy, mammography, interventional, mobile dental and veterinary), Non Destructive Testing (e.g. automotive, electronics, aerospace, energy – Oil/Gases, construction, food, art) and Security (e.g. luggage, transportation, portable and remote inspection with robotics…).

The LORIX innovative action will bring the organic X-ray sensor technologies from Lab validation to Fab demonstration. The project is built on a set of process developments which follows different steps:
- Front-end activities dealing with the process development for reliable large OPD devices on glass or on foil matrices,
- Back-end activities dealing with the prototyping of X-Ray detectors based on TOLAE solution,
- System activities which lead to the integration of the detectors in the final X-Ray demonstration system for the 3 targeted application fields: Security, Non Destructive Testing (NDT) and Healthcare.
First Period:

Most promising X-ray imaging market segments and applications have been selected as well as specification requirements of the system defined for the 3 targeted applications (NDT, security, healthcare)

The definition of the specifications for the detector subsystem has been performed,

Modeling on OPD discrete photodiodes has been initiated,

A test bench adapted to large area sensor matrix on foil has been setting up.

An OPD process flow has been defined on a-Si matrix,

Compatiblity tests of the OPD stack on flex OTFT matrix have been performed.

Specifications of the ALD and AOI (Automatic Optical Inspection) tools have been defined and adapted to the both large area substrates (glass and plastic) used in the LORIX project and to the specific organic materials, Both tools are under construction.

Qualification and reliability protocols of the LORIX detectors have been defined on the basis of the standard current protocols.

Second Period:

Concerning the SoF (Sensor on Foil), specific design of OTFT has been selected for the technology transfer from FlexEnable to Plastic Logic Germany,

The model of OPD (organic photodetector) devices has been improved and several simulations have been performed to analyse the optoelectrical response of the OPD in static and dynamic mode.

The process of OPD on a-Si matrix has been fixed demonstrating reproducible performances of the SoG (Sensor on Glass). Subsequantly, SoG with appropriate electro-optical performances have been selected for integration with the scintillator, the driving electronics and the packaging. It led to achieve DoG (Detector on Glass) demonstrators, which have been characterized to be further tested during the next period according to the 3 applications, NDT/ Security and Medical.

The transfer of the process flow from FlexEnable to the industrial pilot line of Plastic Logic Germany is in good progress and OTFT matrix on foil in Gen 3.5 have been fabricated and further processed with OPD on the top, so that first SoF (Sensor on Foil) have been demonstrated in 24*30 cm2.

The ALD and AOI (Automatic OPtical Inspection) tools have been successfully installed on the PICTIC (Printed Electronics) platform.

Third period

Large area SoF have been characterized in terms of electro-optical performances and the best ones have been selected for integration with the scintillator, the readout electronics and the final packaging. It led to achieve DoF (Detector on Foil) demonstrators, which have been characterized and tested during the period according to the 3 applications of the project.

X-Ray images have then been achieved on both medical and NDT/security clinical phantoms in large area with the DoG provided from the second period and the DoF from the third period.
"Progress Beyond the State of the Art:
LORIX will innovate by first replacing current amorphous silicon sensor by combination of conventional active a-Si:H active matrix on glass with printed OPD. Second by replacement of rigid amorphous silicon based sensor by OTFT active matrix on foil (manufactured with organic material with conventional lithographic processes) associated with printed OPD.

Expected potential Impact:
LORIX will enable the market introduction of new TOLAE based components & products on the high impact mature X-ray imaging market.
The new organic detectors that LORIX aims to develop are addressing the medium volume and high impact ""Digital X-ray image sensor"" market.
LORIX addresses not only the detectors but also the system level in the digital X-ray imaging major segments: industrial inspection systems and healthcare.
Applications targeted by the LORIX project