The disclosure provides a method and to an apparatus for determining the heating state of a mirror in an optical system, in particular in a microlithographic projection exposure apparatus. A method for determining the heating state of an optical element includes: measuring values of a first temperature that the optical element has at a first position using a temperature sensor; and estimating a second temperature that the optical element has at a second position, which is located at a distance from the first position, on the basis of the measured values, wherein estimating the second temperature is accomplished while taking into account a temporal change in the previously measured values.

A compact folded projection system is described that includes a laser light source, a folded lens system comprising a lens stack including two or more refractive lenses and a light folding element (e.g., a prism), and a diffractive beam splitter that includes at least one diffractive surface. The light folding element provides a folded optical axis for the lens system to reduce the Z-height of the projection system, for example to within a range of 1.7 to 4 millimeters (e.g., 2 millimeters in some implementations). The laser light source emits light that is refracted by the lens stack to the folding element. The folding element redirects the light to the beam splitter which replicates the light into NxM duplications or tiles to thus generate a larger field of view (FOV) than the internal FOV of the lens system.

An optical device includes a mirror, and a plurality of actuators configured to deform a shape of a reflecting surface of the mirror. At least some of the plurality of actuators are arranged on a plurality of concentric circles arranged in such a manner that the concentric circles are arranged denser as positions of the concentric circles are located farther from a center of the reflecting surface of the mirror, and at least some of the plurality of actuators are arranged at equal intervals in circumferential directions of the concentric circles.

A compact folded projection system is described that includes a laser light source, a folded lens system comprising a lens stack including two or more refractive lenses and a light folding element (e.g., a prism), and a diffractive beam splitter that includes at least one diffractive surface. The light folding element provides a folded optical axis for the lens system to reduce the Z-height of the projection system, for example to within a range of 1.7 to 4 millimeters (e.g., 2 millimeters in some implementations). The laser light source emits light that is refracted by the lens stack to the folding element. The folding element redirects the light to the beam splitter which replicates the light into NM duplications or tiles to thus generate a larger field of view (FOV) than the internal FOV of the lens system.

A projection lens of an EUV-lithographic projection exposure system with at least two reflective optical elements each comprising a body and a reflective surface for projecting an object field on a reticle onto an image field on a substrate if the projection lens is exposed with an exposure power of EUV light, wherein the bodies of at least two reflective optical elements comprise a material with a temperature dependent coefficient of thermal expansion which is zero at respective zero cross temperatures, and wherein the absolute value of the difference between the zero cross temperatures is more than 6K.

An optical system for field imaging and/or pupil imaging has an optical axis, a stop plane and an image plane. The optical system includes a lens element system that has three lens element groups, each including at least one lens element. The lens element groups are spaced apart from each other along the optical axis between the stop plane and the image plane. The three lens element groups have a first lens element material and/or a second lens element material that differs from the first lens element material.

An image display device includes an image light generation unit configured to generate image light, a projection system optical unit configured to project the image light, a correction system optical unit configured to correct aberrations, a first diffraction element configured to deflect the image light incident on a first incident surface, and a second diffraction element configured to deflect the image light incident on a second incident surface. The projection system optical unit, the second diffraction element, the correction system optical unit, and the first diffraction element are arranged in this order in a direction of the image light emitted from the image light generation unit, and the image light deflected and dispersed into rays of respective wavelengths by the second diffraction element is focused by the first diffraction element.

An immersion lithography apparatus has a controller configured to control a substrate table to move along an exposure route including in order: an entry motion in which the substrate moves from an off-substrate position at which the immersion space does not overlap the substrate to an on-substrate position at which the immersion space at least partially overlaps the substrate, a transfer motion in which the substrate table changes speed and/or direction and moves for at least a transfer time after the substrate moves to the on-substrate position, and an expose motion in which the substrate is scanned and the patterned beam is projected onto the substrate, wherein throughout the transfer motion at least a part of the immersion space overlaps the substrate and wherein the patterned beam is not projected onto the substrate during the entry motion and the transfer motion.

Disclosed is a method for correcting an image, a storage medium, and a projection device. The method is applied to a projection device, the projection device including a grating and a light generation component. The method includes: determining, in a region in which a projection image projected by the projection device overlaps with a projected image projected through the grating by detection light output from the projection device, diffraction spots having a diameter not equal to a preset value as target diffraction spots; determining a group of target diffraction spots continuously arranged in a horizontal or vertical direction, as well as diffraction spots having a diameter equal to the preset value that are respectively located on both sides of the group of target diffraction spots, as a region to be corrected; determining an angle .sub.i between a plane of an i.sup.th diffraction spot and a plane of an (i+1).sup.th diffraction spot that are adjacent in the horizontal or vertical direction in the region to be corrected; and determining a corrected projection length of the (i+1).sup.th diffraction spot according to the preset value and angles .sub.1 to .sub.i.

An imaging optical system comprises adjusters for adjusting a shape of each of at least two reflecting surfaces by applying a force to a rear surface of each of the reflecting surfaces. Points obtained by projecting force acting points of the adjusters in an optical axis direction defined with respect to the reflecting surface are defined as correction points, the acting points are set such that, when first and second rays in a light flux emitted from one point on the object plane are reflected by first and second reflecting surfaces, the first ray strikes the correction point of the first reflecting surface but does not strike the correction point of the second reflecting surface, and the second ray does not strike the correction point of the first reflecting surface but strikes the correction point of the second reflecting surface.