摘要:
A method of making a fracture-resistant large-size calcium fluoride single crystal is described, which is suitable for an optical component for radiation in the far UV range. The calcium fluoride raw material for the single crystal is first melted and subsequently solidified by cooling the melt to form a single crystal. However the calcium fluoride raw material is doped with from 1 to 250, preferably 1 to 100, ppm of strontium, preferably added as strontium fluoride, and contains from 1 to 10 ppm of sodium as well as up to 100 ppm of other impurities.
摘要:
A device is used to hold an optical element, in particular one made of a crystalline material, in particular of CaF2, while the optical element is being coated, in particular by the vapor-deposition of at least one functional layer in a vacuum coating plant. The latter has a device for mounting the optical element, it being possible for the optical element to be heated in the vacuum coating plant via suitable radiation, in particular infrared radiation. An intermediate element which has a lower thermal absorption than the device for mounting the optical element is arranged between the device for mounting the optical element and the optical element.
摘要:
A method for repairing optical elements having a coating, in which the coating is fully or partially removed or left on the optical element, a polishing layer being provided in the coating or a polishing layer being applied, which allows simple processing of the surface to achieve high geometrical accuracy and lower surface roughness. A new coating is applied onto the corresponding polishing layer. Also addressed are corresponding optical elements, including optical elements recycled according to the method.
摘要:
The invention relates to an imaging system of a microlithographic projection exposure apparatus, proposing improvements in the protection of exterior optical surfaces against contamination. In an imaging system with a projection objective that serves to project an image of a mask which can be set in position in an object plane onto a light-sensitive coating that can be set in position in an image plane, a membrane which is substantially transparent for an operating wavelength of the projection objective is arranged in such a way in relation to an exterior optical surface of the projection objective that between said optical surface and the membrane an interstitial space is formed which is designed to receive a liquid or gaseous medium.