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Flexible Optical Injection Moulding of optoelectronic devices

Periodic Reporting for period 3 - FLOIM (Flexible Optical Injection Moulding of optoelectronic devices)

Período documentado: 2021-03-01 hasta 2022-08-31

Miniaturized, integrated photonic devices are driving an increasing number of applications, while facing pressure to lower cost and increase flexibility. Optoelectronic devices production chain is inherited from microelectronics, which is not appropriate for novel, low cost, high efficiency photonic devices.
FLOIM concerns a new automatized manufacturing technology to produce optoelectronic components and assembly the corresponding optical system, based on the use of thermoplastics for embedding all the components into a compact and robust unique device.
Improving cost efficiency, flexibility and environmental footprint of the complete optoelectronics workflow, can provide European industry with a key tool for excelling in advanced applications and differentiating their products, while keeping production, innovation capacity and key Intellectual Property in Europe, which is the main goal of FLOIM.
FLOIM aims to develop a manufacturing platform integrating the optical embedding technology for high-precision injection moulding by multiscale structuring of mould cavity inserts. This platform also includes in line quality assessment tools and instrumentation to extract information from the process, machinery and produced parts to perform full quality evaluation and prognosis towards a zero-defect paradigm, while providing full process control and automation.
The project aims to the following technical goals:
•Novel manufacturing chains for high quality integrated optical devices
•Design new manufacturing equipment for functional optical embedding
•Custom optical functions through mould insert machining and structuring
•Sustainable production of eco-friendly optoelectronics
•Disruptive applications
R&D and demonstration were handled towards the main objectives. Specifications were established for the three demonstrators of the project: Fibre Optic Transceiver (FOT), Optical Encoder Head (OEH), and Back Light Units (BLU). Benchmarks were established based on competing products, or the state-of-the-art equipment and technologies when a direct competitor does not exist. Three research lines were developed in parallel: mould inserts micro structuring, injection moulding of optical components and in line quality control and alignment. Tooling technologies were optimized to fulfil the industrial requirements; the injection moulding process was optimized for the different demonstrators; and the assembly of the pilot line including the manufacturing equipment and the quality control systems was completed.
For inserts micro structuring, multiple technologies have been studied to achieve the requirements of the different products. Micromilling technology used for generating optical quality surfaces was also studied to manufacture gratings within the micrometric scale, obtaining excellent local homogeneity. Laser direct writing, Ion Implant Lithography (IIL) and multi-photon polymerization (MPP) have been used for generating patterns on steel mould inserts, which were replicated by injection moulding, providing advanced optical functionalities without increasing the final part size or the processing steps. Volume gratings on transparent materials was also analysed to manufacture diffraction gratings with promising results. These technologies have been completely validated within the demonstration activities.
Different injection moulding trials have been performed for the demonstrators: i) Hundreds of FOTs have been successfully injected without damaging the wires. ii) Diffraction gratings for the OEH have been reproduced in small areas, demonstrating good replication capabilities. iii) Large areas of the BLU have been overmoulded with different materials, showing the challenge of avoiding variability regarding the adhesion grade between the LEDs and the injected polymer.
Optical Coherence Tomography (OCT) and fibre optic interferometry have proven to be suitable technologies for the monitoring and quality assessment of the injection process. The OCT system has been tested with real FOT samples, allowing to detect anomalies within the injected material and to evaluate damage on the wires during the injection. Fibre optic interferometry was tested for measuring small displacements of a polymer, achieving resolutions better than one micron. A mechatronic device for assuring the automatic alignment of the components during the injection process, was designed and built. This system, along with the OCT, have been integrated in a mock-up mould for industrial validation.
The pilot line designed to manufacture the FOT has been installed, integrated and validated. All the equipment has been purchased and customized according to the manufacturing line requirements. The automated cell for the back-end processes has been assembled and validated. The front-end line, the injection station and the final processing robotic cell have been integrated into the accommodated clean room And ramping-up and commissioning actions have been successfully completed.
Regarding dissemination and communication, at the beginning efforts were put onto raising awareness of the project among target audiences. Lately, the results of the project have been presented on scientific publications, congresses and exhibitions. These results include the work performed by direct laser writing, MPP, fibre optic interferometry and mechatronic alignment, among others.
By the end of the project multiple advances beyond the state of the art have been reached. Resolution of under a micron has been achieved and the tooling technologies have been demonstrated as suitable for the injection moulding. Optimization regarding the patterning of the inserts, especially on large areas, as well as the replication process by injection moulding has been carried out with promising results accomplished. Replication accuracy and reduction of induced stresses in the structured surfaces are guaranteed by the combination of injection compression moulding and injection moulding, increasing reliability, adhesion and performance.
OCT and fibre optical interferometry have proved to be valuable technologies to achieve the required in-line and in-mould quality control. The OCT system has been integrated into the developed mechatronic alignment module and both systems have been validated together through multiple injection trials. Thereby, a future integration of these technologies will allow process control and optimization and quality prediction, providing with near real-time inspection data and prognosis.
FLOIM’s demonstrators will benefit from a shorter lead-time, reduced cost and higher productivity yield; due to the reduction of manufacturing steps, automation of the process, use of thermoplastic materials and the 100 % in-line quality assessment. The steps have been reduced thanks to the patterning of mould inserts, which remove the necessity of adding further optical elements, while enabling higher compactness of the product and reducing energy losses in the injected optical component, thus increasing the overall energy efficiency of the device.
The financial projections have been estimated considering the exploitation of KER1, KER2 and KER4 by involved project partners (KER exploitation leaders). Financial projections were depicted based on 5 years sales, and full financial statements (i.e. Balance Sheet, Cash Flows and Profits & Loss statements) were developed to complement and improve reliance (see deliverable D8.5).
MPP Glass
KER2 forecasted economic projections for commercialisation supporting
Diffusive pattern
4 point diagram
FlexEnable - 12.1-inch Conformable OLCD
SEM image of IIL structures made by ADAMA
OCT laboratory setup for future in mould quality control at RECENDT
Impact Table
FLOIM logo
KER1 forecasted economic projections for commercialisation
Mechatronic alignment device concept
Laser micro and nanostructured mould insert processed at Ceit with a high repetition femtosecond las
Overmoulded BLU
OCT reconstructed 3D image of a measure sample by RECENDT
FLOIM target - Masssive manufacturing of optoelectronic devices