Sammenhengen mellom mikrofeil i optiske aktive elementer og sammenbrudd i mekanisk, fysisk og elektrisk testing

The microfail project is focused on understanding the effect of microfailures and defects on issues observed on product level, that can influence the lens performance and/or reliability. The first year of the project was particularly focused on problems in drop test. We have observed that components might experience accelerations of up to 50000 times the gravitational acceleration (50000G). These are extreme impacts. They also tend to be very chaotic and the reliability requirement for mobile phone with respect to drop test and chock impact seems to increase over years, moved from 5000G (0.8m free fall in bulky and soft old fashion mobile phone in the 2000 to today super slim and stiff mobile phone free fall drop from 1.5m 50KG. Future new requirement could go up to 2m free fall drop test. Early in the project, we identified a method to drastically improve the drop test resistance of the lenses. A patent application has been filed, and the method is implemented in the production line for all TLens products. During the year, we have also completed a full product qualification, including an extensive reliability test program. The realization that correct and controlled mounting of lenses in drop test jigs has been an important finding. This was accomplished by extensive experimental work, statistical analysis and theoretical simulations, and led to a deeper understanding of the complex correlations between conditions in the drop test jig and drop test performance. By controlling/reducing the possibility for the lenses/cameras to move inside the drop jigs, the failure rate in drop test was reduced from 20% to below 5%, which is considered to be sufficient to claim that the issues we have faced with drop test over the past 2-3 years have been resolved. 2020 was a very positive year for the company. Our first products was qualified and put into production for use in smart watches. In the same period, we have identified some new effects that may reduce functionality and lifetime. We have already found solutions that are implemented. The post-doc student had good progress until early in 2020. An application for synchrotron beam time (high energy X-ray diffraction) has been filed, where the plan is to do high resolution stress and property mapping of TLens actuators. The post-doc student had a challenging year in 2020 due to Covid19. We had a slot at the Synchrotron in march that was postponed to october this year. Later it was postponed until notice is given. We were not able to carry out these analysis within the time frame of this project. Other laboratory analysis was also cancelled and we had to use in-house equipment or equipment belonging to production partners. A number of adjustments and changes has been implemented both in design of lenses together with customers and in wafer processing and assembly of lenses with our production partners. These adjustments and changes has improved both failure rate and performance of our lenses, but we have discovered some new minor issues that we have started to investigate.

I den opprinnelige søknaden er ikke tatt inn noen tekst knyttet til virkninger og effekt, derfor vil vi her i hovedsak fokusere på hva som er oppnådd: - Vi har identifisert feilmekanismer og kritiske feil. - Løsninger er prøvet ut og implementert i produsjon. - Mere optimale designløsninger for kundens produkter er utviklet og implementert. - Patentsøknader på viktige elementer av teknologien er innsendt. - Covid 19 har skapt utfordringer for prosjektet og deler av arbeidet måtte replanlegges - Feil raten har sunket, men vi har ikke nådd en feilrate på 5%

poLight as has developed their Tlens technology through the last years and the first product (Silver) is now entering in to mass-production. The next step will be development of new products such as AF-lenses with larger apertures as well as Optical Image Stabiliser (OIS) and an integrated OIS-AF. This require a range of new knowledge which will be aquired through R&D project together with SINTEF, NTNU, HSN and a number of sub-suppliers. Parts of this work i organized in projects partly funded by Forskningsrådet (BTHE, HybridMEMS, HiFPac and this new project Microfail) Microfail is devoted to understanding the effect of micro fails and defects on any observed issue like cracks, delamination, corrosion, moisture absorption and haziness. Larger, more complex structures like OIS are most likely more sensitive to these defects and it is important that we are able to control them. Samples are selected from our product test programs (Not a part of this project) and made in controlled experiments due to time temperature and environment. All selected samples are analysed by SINTEF and NTNU and evaluated in cooperation with poLight scientists. A number analytical techniques will be used including destructive and non-destructive tests described in the project description. We may also need analytical instruments not available in Norway. Through our partners we may use facilities in SNRF, CERN and som other laboratories. Finally we will tune and adjust wafer processing parameters and assembly process to avoid or reduce the number of defects.