Graduate stage design portfolio of Jessica Fialko

På jordklotets nordliga breddgrader påverkas människor av mörka säsonger med liten tillgång till dagsljus, med fysiska påföljder så som sömnproblem och energibrist. Problemet kan minskas med ljuskällor som kan imitera soldygnet men dessa produkter lämnar föga åt fantasin. Denna studie har undersökt möjligheten att genom produktdesign imitera nordbors perception av dagsljus inomhus för att erbjuda användaren en emotionell upplevelse. Genom användarcentrerad design och kvalitativa metoder sammanställdes empiriska data för att skapa en samlad bild av nordbors perception av dagsljus inomhus. Studiens teoretiska ramverk berörde även ljusdesign och framför allt human-centric lighting samt ludisk design. Studien visar att det är av stor vikt att erbjuda individanpassning i denna typ av produkt för att förse användaren med en emotionell upplevelse. Slutkonceptet är en takarmatur för hemmet som erbjuder användaren lekfull design och interaktion, möjlighet att återskapa dygnsrytm samt en imitation av den egna perceptionen av dagsljus. / On the northern latitudes of the globe, people are affected by dark seasons with little access to daylight, with physical effects such as problems sleeping and loss of energy. The problems can be reduced with light sources that can imitate the sun, but these products leave little to the imagination.This study has investigated the possibility of imitating northerners’ perception of daylight indoors through product design to offer the user an emotional experience. Through user-centered design and qualitative methods, empirical data were compiled to create a unified image of northerners’ perception of daylight indoors. The study's theoretical framework also included lighting design, above all, human-centric lighting and ludic design.The study shows that it is of great importance to offer individual customization in this kind of product in order to provide the user with an emotional experience. The final concept is a light fixture for the home that offers the user playful design and interaction, the opportunity to recreate the circadian rhythm and an imitation of one's own perception of daylight.

The past decade witnessed the rapid development of III-nitride light-emitting diodes (LEDs) and laser diodes (LDs), for smart lighting, visible-light communication (VLC), optical storage, and internet-of-things. Recent studies suggested that the GaN-based LDs, which is free from efficiency droop, outperform LEDs as a viable high-power light source. Conventionally, the InGaN-based LDs are grown on polar, c-plane GaN substrates. However, a relatively low differential gain limited the device performance due to a significant polarization field in the active region. Therefore, the LDs grown on nonpolar m-plane and semipolar (2021)-plane GaN substrates are posed to deliver high-efficiency owing to the entirely or partially eliminated polarization field. To date, the smart lighting and VLC functionalities have been demonstrated based on discrete devices, such as LDs, transverse-transmission modulators, and waveguide photodetectors. The integration of III-nitride photonic components, including the light emitter, modulator, absorber, amplifier, and photodetector, towards the realization of III-nitride photonic integrated circuit (PIC) offers the advantages of small-footprint, high-speed, and low power consumption, which has yet to be investigated. This dissertation presents the design, fabrication, and characterization of the multi-section InGaN laser diodes with integrated functionalities on semipolar (2021)-plane GaN substrates for enabling such photonic integration. The blue-emitting integrated waveguide modulator-laser diode (IWM-LD) exhibits a high modulation efficiency of 2.68 dB/V. A large extinction ratio of 11.3 dB is measured in the violet-emitting IWM-LD. Utilizing an integrated absorber, a high optical power (250mW), droop-free, speckle-free, and large modulation bandwidth (560MHz) blue-emitting superluminescent diode is reported. An integrated short-wavelength semiconductor optical amplifier with the laser diode at ~404 nm is demonstrated with a large gain of 5.32 dB at 6 V. A high-performance waveguide photodetector integrated LD at 405 nm sharing the single active region is presented, showing a significant large modulation bandwidth of 230 MHz. Thus these seamlessly integrated elements enable photonic IC at the visible wavelength for many important applications, such as smart lighting and display, optical communication, switching, clocking, and interconnect. The findings are therefore significant in developing an energy-saving platform technology that powers up human activities in a safe, health- and environmental-friendly manner.

Lighting technologies have evolved over the years to become higher quality, more efficient sources of light. LEDs are poised to become the market standard for general lighting because they are the most power efficient form of lighting and do not contain hazardous materials. Unfortunately, LEDs pose unique problems because advanced thermal management is required to remove the high heat fluxes generated by such relatively small devices. These problems have already been overcome with complex packaging and exotic materials, but high costs are preventing this technology from displacing current lighting technologies. The purpose of this study is to develop a low-cost LED lighting package capable of successfully managing heat. Several designs were created and analyzed based on cost, thermal performance, ease of manufacturing, and reliability. A unique design was created which meet these requirements. This design was eventually assembled as a prototype and initial testing was conducted. This thesis reviews the design process and eventual results of the LED package design.

With experimental realization, energy harvesting capabilities of chaotic microstructures were explored. Incident photons falling into chaotic trajectories resulted in energy buildup for certain frequencies. As a consequence, many fold enhancement in light trapping was observed. These ellipsoid like chaotic microstructures demonstrated 25% enhancement in light trapping at 450nm excitation and 15% enhancement at 550nm excitation. Optimization of these structures can drive novel chaos-assisted energy harvesting systems. In subsequent sections of the thesis, prospect of broadband light extraction from white light emitting diodes were investigated, which is an unchallenged but quintessential problem in solid-state lighting. Size dependent scattering allows microstructures to interact strongly with narrow-band light. If disorder is introduced in spread and sizes of microstructures, broadband light extraction is possible. A novel scheme with Voronoi tessellation to quantify disorder in physical systems was also introduced, and a link between voronoi disorder and state disorder of statistical mechanics was established. Overall, in this thesis some nascent concepts regarding disorder and chaos were investigated to efficiently manage electromagnetic waves in optoelectronic devices.

The diploma thesis deals with the industrial inspection of correctly made connectors based on computer recognition, and the detection and recognition application is implemented in Python on the Raspberry Pi platform.The work uses empirically known OpenCV library for recognition. The work also deals with the selection of suitable hardware devices, which are a camera with a lens and an illuminator, from which is created one compact device together with the Raspberry Pi microcomputer. The compact device is further mounted on the designed mechanical structure under which is created inspection zone. Finally, Raspberry Pi has a web-based user interface to check the inspection and the interface to write the data to the database.

This diploma thesis deals with the design and testing of a system for powerline communication, enabling control of LED lights. The work first describes the basic principles of powerline communication, specifies the communication bands and summarizes the basic functional requirements for communication within the system for LED lighting control. It also describes the method of selecting a modem for powerline communication, the design of a test module with this modem and also the method of testing real communication between two test modules, including test results. The most comprehensive part of the work describes the design of hardware and software of the universal PLC module and how to use it. In addition, it referes to the development tools used as an example of implementation in LED lighting. At the end of the work are summarized the results of testing the proposed system.

Light guide is a tubular skylight with mirrored internal surface. It is a lighting device bringing daylight into the interior of a building without windows or into rooms with insufficient daylight. It presents the potential for energy savings, opens the possibility to use places that are not well lit and offers opportunities for improving the visual comfort of the indoor environment. This thesis reviews the potential of light guide system as a daylighting approach in building and presents results of experiments on performance of tubular skylight prototype. The main task of the thesis is focused on comparison of traditional light guide system and newly developed prototype, examination of its light transmittance and efficiency as well as its thermal behaviour in order to find possible improvements for applications in buildings.

Theoretical part of this thesis describes LEDs and other circuitry used for LED light design. LED light is designed, manufactured and put into operation. This thesis examines possibilities of measuring exterior light and its key parameters. The device uses two sets of LEDs – warm white and cold white to create light with parameters dependent on exterior light. LEDs are driven by constant current sources that are designed, manufactured and examined in this thesis. The device is microprocessor-controlled, which allows to switch between multiple modes of operation. Flyback SMPS is used to power the microcontroller.

The aim of this thesis is to design a system for monitoring and control battery charge of emergency lighting. Discuss and choose components with respect to cost and accessibility. Design full circuit scheme and PCB with chosen components is provided. Designed system is compiled and tested in order. The item of discussion is measured discharging characteristics and conditions of accumulator.