Patent Number: 
Section: claims

1. A method of adjusting the illumination in a plane that is illuminated by an illumination system, wherein the illumination system comprises a first raster element and a second raster element, and wherein the position of the first raster element relative to the second raster element is changed in such a way that a predetermined illumination is achieved in said plane. 2. The method of claim 1, wherein the fist raster element is offset in a first plane relative to the second raster element and/or the second raster element is offset in a second plane relative to the first raster element. 3. The method of claim 1, wherein the second raster element is put into a tilted position relative to the first raster element. 4. An optical device for an illumination system for a microlithographic projection exposure apparatus, comprising a first raster element which receives light of a light source, wherein the first raster element produces a light source image of the light source on a second raster element, wherein the light source image is of a magnitude and the second raster element is of a width that is larger than the magnitude of the light source image, and wherein the first raster element can be changed in its position relative to the second raster element. 5. The optical device of claim 4, wherein the first raster element is part of a multitude of first raster elements, wherein said multitude of first raster elements forms a first optical element, in particular a first faceted optical element. 6. The optical device of claim 4, wherein the second raster element is part of a multitude of second raster elements, wherein said multitude of second raster elements forms a second optical element, in particular a second faceted optical element. 7. The optical device of claim 5, wherein the first optical element is arranged in a first plane and the first optical element is configured to be movable in the first plane, so that by moving the first optical element the position of the first raster element is changed in relation to the second raster element. 8. The optical device of claim 6, wherein the second optical element is arranged in a second plane and the second optical element is configured to be movable in the second plane, so that by moving the second optical element the position of the first raster element is changed in relation to the second raster element. 9. The optical device of claim 5, wherein a first multitude of first raster elements are arranged in a first column and a second multitude of first raster element are arranged in a second column, and the first raster elements in the first column have a first multitude of first limits and the raster elements in the second column have a second multitude of second limits, and wherein the first column is moved in relation to the second column in a direction along the column, so that the first limits have an offset in relation to the second limits. 10. The optical device of claim 4, wherein the first raster element is configured in a reflective design as a first raster mirror element. 11. The optical device of claim 10, wherein the second raster element is configured in a reflective design as a second raster mirror element. 12. The optical device of claim 11, wherein the second raster element is arranged to be tiltable relative to a plane. 13. The optical device of claim 4, wherein the first raster element has substantially the shape of a field to be illuminated. 14. An illumination system for use in microlithography, comprising the optical device of claim 4, wherein a field in a field plane is illuminated. 15. The illumination system of claim 14, further comprising a mirror and/or lens device that is arranged so that it follows the optical device in the light path from the light source to the field plane. 16. The illumination system of claim 14, further comprising a field aperture stop. 17. The illumination system of claim 14, wherein the optical device is of a refractive design. 18. The illumination system of claim 14, wherein the optical device is of a reflective design. 19. An illumination system for use in microlithography, comprising a first optical element serving to form a multitude of light source images of a light source on a pupil raster element of a second optical element, wherein devices are provided by which the position of the light source images on said pupil raster element can be changed.