Mikrolitografi för rastrerade Gobos

• Main Author: Nilsson, Daniel
• Format: Others
• Language: Swedish
• Published: Linköpings universitet, Institutionen för teknik och naturvetenskap 2005
• Subjects: Datorteknik; rastrering; halftoning; LIOS; Computer Engineering
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2861

Beacon AB has been producing Gobos for some time. A Gobo is a small round sheet used in projectors almost like a slide. It is used mostly in the commercial and entertainment business. Today these Gobos are created by using a film (also called mask). A digital exposure machine called LIOS has been developed to make it possible to create Gobos using direct exposure. This means a film will no longer be necessary and it will also make the process faster and cheaper. To be able to use LIOS in the industry a lot of work still has to be done. An image is sent to the display in LIOS. This image comes from a computer connected to LIOS and at the end of the process it will be reproduced on the Gobo. This image can be modified before it is sent to LIOS so that a better result can be achieved in the end. The problem is that once the process is complete the image will be binary, which means halftoning is going to be used. The goal of the research described in this paper is first to test the properties of LIOS, second to create a halftoning method especially designed for those properties. The resultof this thesis is an AM (Amplitude Modulated) method that uses a modified threshold matrix. Using this method would not give a satisfying result unless some of the distortions could be corrected somehow. This can however be done using a property available for the display in LIOS. The display can handle grayscales but since etching is used later in the process the final result will be a binary image (only black and white). This means that even though the image will be binary in the end, these grayscales can still be used to improve the result. The equipment that was available when this thesis was done was not fully developed why the grayscales are used to correct distortions. The resulting method will most likely be good enough to produce Gobos with a satisfying quality. The method has never been used before and it introduces a new way of making corrections for halftoning. There are still some practical problems left to solve before LIOS can be used to reliably produce Gobos. Using better equipment can solve several of these problems but not all of them.