This report examines the prerequisites for LEDs to replace other technologies indifferent applications. How does the different technologies for light generationwork and what are the advantages and disadvantages? The various technologieslimitations and characteristics provides the opportunities for the LEDs.This report describes a test-construction built to examine what practical arrangementscan be built with modern Light emitting diodes, in order to showsome of the possibilities. The construction consists of three different applications,a high power lamp based on cold white LEDs, one based on warm whiteLEDs for the evaluation of the light characteristics and a RGB-LED based lampable to mix any colors quickly and seamlessly. The test construction also containsthe essential peripherals including control-electronics, optics and a custombuilt watercooling solution.The potential for LEDs is huge but it is complicated to build LED based applicationsdue to the limitations which mainly includes the electronics and theneccesary cooling.

Organic Light emitting Displays (OLEDs) are a new type of thin emissive displays predicted to possess superior properties to existing techniques e.g. Liquid Crystal Display (LCD). The main advantages are low power consumption and a thin display structure. This report contains an explanation of the emissive OLED technology, its functionality and the physics of the organic layer structure in an OLED. The technology is described with respect to the two classes of organic materials used in displays, small molecules and conjugated polymers.

The purpose of this master thesis has been to find different solutions to the design of a headlamp with a cluster of three or possibly four high power LEDs (Light emitting Diodes). During the work, two different problems have been considered; how to design a lens in order to shape the light beam in a desirable way, and how to design a cooling system which will lower the temperature of the LEDs as efficiently as possible, still taking into account the geometry set by the optical solution as well as other given geometries. The results presented in this thesis are partly the outcome of a literature study, but derive mainly from a number of tests and measurements made on two test rigs and one concept prototype..

AbstractMy task was to prepare the already designed heating list ?Stayhot? for manufacturing.I started with drawing the whole list in the CAD-program. It became obvious that some of the designed components had to be changed to work in practice.A turnable reflector couldn?t be combined with the isolation. The suggested Light emitting diodes wouldn?t give enough light, so I cut them out and the problem with light remains to be solved.

Denna rapport beskriver ett examensarbete där optiska fibrer av plast integrerades i varpled i en väv. Syftet med examensarbetet var att undersöka om det är möjligt att industriellt producera ljusemitterande vävar med optiska fibrer. Arbetet delades upp i olika delar, både teoretiska och praktiska. Den teoretiska delen innebar informationssökning inom olika medier, såsom vetenskapliga artiklar och intervjuer med insatta människor inom de berörda områdena. Den praktiska delen i examensarbetet bestod av flera olika moment.

Lumilos is a work investigating the possibilities to use light and color in an interactive design context. I have explored different light sources and compared them to each other and given a short description of the history of light and how it has been developed during the industrialization in the western world. I have also investigated what is currently done in the field and summarized that with examples in the categories passive-, colored-, material- and interactive light. The conclusion is that working with interactive color and light is a hard task. There are many different angles to take into account such as personal likings and earlier experiences that is uncontrollable by the designer. Yet there are many possibilities and light is a material that is moldable in many forms. I have put the knowledge about light and color into practice and developed an interactive light wall that is visualizing energy consumption with the use of different colors of light and animations.

Inspired by how to sketch a light cone from a flashlight in a comic I wanted to create an armature carried only by its own light cone. To manage this challenge I sketched in an architectural and sculptural way, where I chose to ignore the function of the lamp as long as possible.As a result I developed an armature with a stunning shape, with an illusion that it was carried by its own light cone. It could be hanged on a wall, placed on a table, pushed against a ceiling or standing on the floor.Depending of its size the light cone from the light source lightens up the surface and draws attention to the otherwise forgotten wallpaper or the undisposed statue in the darkness of the city..

The animal welfare act in Sweden states that dairy cows need to have at least a dim light present at night, but there are no recommendations for what intensity the light should have. It is unknown how cows perceive and react to low light intensities and earlier studies on this topic are limited. Red light as night light has also been suggested, based on the cows? inability to perceive red light. This have however been questioned. The aim with this study was to investigate how four different light intensities affect dairy cows behavior.

The purpose of this review was to study the cow eye physiology, focusing on how it registers light, and to see how light affects the cow?s milk yield. It has been showed in studies that more hours of light per day (16 hours of light a day) as opposed to about 9-12 hours of light a day, increases milk yield for dairy cows. This review contains suggestions on how this is connected with the physiology of the eye. Vision is an important sense for many mammals, and is used to check out the animals surroundings. Sensor cells in the eyeball help in turning photons from the light into signals to the brain.

In this study, we investigate various lighting applications in a virtual environment, where we compare between light based in naturalism (natural light) and pictorialism (artistic light). The purpose of this study is to gain further knowledge in lighting, which is increasingly important for game graphics. Theory are examined to gather information and recommendations on how to use various light settings that convey different emotions. We then use this information to illuminate the environment that we have built. The environment is presented in Unreal 4 for respondents who are allowed to move around freely in the environment.

The aim of the study was to examine the retinal ON- and OFF-pathways of the canine electroretinogram (ERG). The ON- and OFF-pathways are used to distinguish objects from their backgrounds. A dark object is discernible from a lighter background using the OFFpathway and the ON-pathway is used to descry a light object upon a darker background. This study shows that the dog ERG has both ON- and OFF-responses and that these responses can be separated by prolonging the flash duration over 50 ms. The dog OFF-response waveform was more similar to the cat OFF-response than the human OFF-response (Frishman, 2006; Zrenner and Gouras, 1979). In this study six female three-year-old Beagle dogs were included. Both background and flash stimuli were provided by LEDs (Light emitting diodes) with a wavelength of 470 nm, a wavelength that is absorbed almost as effectively by the canine M/L-cones as by the S-cones. These stimuli gave ERGs with both ON- and OFF-responses.

The relation between the cave and the circumpolar light conditions has long been a part of the interpretation of the meaning of the Norwegian cave art. This paper explores the relationship by trading the concept of a sensory dichotomy between light and darkness for that of a perceptual relationship between the paintings, the environment and the light..

This work is an exploration of a method and how to find balance between it and its contents. One part consists of a technical study on how to use UV light to yellow distinct surfaces on paper and the other is about how to find use of the method. The common denominator is determined as the consequence of the relationship between light and time. The result is three images that shows various traces of time with time as a graphic expression..

The aim of this study was to investigate the relationship between sleep, photoperiod, milk yield and hormones connected to milk formation. Variations of prolactin (PRL) and Insulin-Like growth factor-1 (IGF-1) in plasma were measured during two different light programs. The light programs consisted of either 24 hours of light (L24:D0) or four hours of light and 20 hours of darkness (L4:D20). Five cows of the Swedish Red breed were used in a cross-over experiment and each light program consisted of five days. Milk yield was measured at every milking and milk samples were analyzed with regard to fat, lactose and protein.

Light has always fascinated humans but ever since the invention of the first light bulb, the use of artificial lighting has accelerated dramatically. Darkness has never been as rare as today and the overuse of lighting has created a new phenomenon called light pollution. Most living beings are biologically dependent on the recurrent twenty-four-hour rhythm of light and darkness, called the circadian cycle. Human beings are evolutionary developed after this circadian rhythm and the effects of constant artificial light is yet unknown. Scientists fear the consequences of constant lighting and what it means physically, mentally and philosophically for the human species.