| 摘要 |
A method of making a porous filter element by defining in a body of photosensitive material a pattern of varying intensity e.m. radiation (e.g. light), by creating an interference pattern in the material. After exposure to the e.m. radiation, regions of the material are selectively removed (e.g. dissolved away) in dependence upon the exposure to which they were subjected. This results in a porous element which can be used directly as a filter element, or which can be used as a lost mould to create a filter element from a different material. In that usage the voids in the resin material are filled with the material from which it is desired to make the filter, and then the resin is removed. Varying the intensity and the pattern varies the size, shape and disposition of the regions which are removed, and thus of the pores in the filter.
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