Sökning: "refractive lenses"

Visar resultat 1 - 5 av 20 avhandlingar innehållade orden refractive lenses.

1. 1. MULTIFOCAL SPHERICAL FISH LENSES

   Författare :Yakir Gagnon; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Multifocal Lens; Adaptation; Dispersion; Spherical lens; Model; Fish; Ray-trace; Longitudinal Chromatic Aberration; Longitudinal Spherical Aberration; Modulation Transfer Function; Point Spread Function; Refractive Index Gradient;

   Sammanfattning : Vision is an important source of information for many animals. The lens plays a central role in the visual pathway and hence the ecology of these animals. Fish have spherically shaped crystalline lenses that contain a gradient of refractive index. Like all refracting elements, lens performance depends on the wavelength of the refracted light. LÄS MER

3. 2. Fish Lenses : Anatomy and Optics

   Författare :Tomasz M Kozłowski; Funktionell zoologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Plasticity; Development; Cellular structure; Lens fiber cells; Modeling; Laser Scanning; Schlieren photography; Fast Fourier Transform FFT ;

   Sammanfattning : I have investigated some of the biological regulatory mechanisms governing the development of crystalline lenses. I used fish as model animals because they possess optically interesting lenses, while the geometrical simplicity of fish lenses allows for studies that are difficult or impossible with the lenses of other animals. LÄS MER

4. 3. A multi-prism lens for hard X-Rays

   Författare :Björn Cederström; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; x-ray; optics; refractive; lens; mammography; synchrotron; Physics; Fysik;

   Sammanfattning : This thesis describes a new type of refractive lens for hardx-rays. It is shown that a linear array of prisms, slightlyinclined with respect to the optical axis, will form a linefocus at a certain distance from the lens. Hence, the namemulti-prism lens. LÄS MER

5. 4. Polymer Microoptics in Silicon Micromachining

   Författare :Karin Hedsten; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MOEMS; amorphous fluorocarbon polymer; polymer microlens; silicon micromachining; replication; refractive lenses; diffractive optics; MEMS; Cytop™; transmissive microoptics; reflow;

   Sammanfattning : MEMS (micro-electro-mechanical system) technology is an established field, which makes use of the advanced state of silicon processing to fabricate complex electro-mechanical structures and devices. Microoptics is a new, but advanced technology within the field of optics. LÄS MER

7. 5. Ocular aberrations and visual quality in aspherical and multifocal contact lenses

   Författare :Anna Lindskoog Pettersson; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :Contact lenses;

   Sammanfattning : Good visual quality and precise accommodation are required to be able to focus objects at distance and near, and are essential in order to be able to perform most tasks in life. Most eyes are not ideal eyes, i.e., they have different refractive errors which distort the produced image. LÄS MER