A method for adjusting the magnification scale of an optical imaging device for exposing or inspecting substrates is provided. The optical imaging device includes a first optical element group, which includes a plurality of first optical elements in an imaging beam path. The method includes replacing optical elements of the first optical element group in the imaging beam path by optical elements of a second optical element group for the purposes of adjusting the magnification scale. The first optical element group includes two reflecting optical elements with first optical parameters, which define a first Petzval sum. The second optical element group includes two reflecting optical elements with second optical parameters, which define a second Petzval sum. The value of the first Petzval sum is at least substantially identical to the value of the second Petzval sum.

A reflective afocal switching assembly permits variable fields of view while at the same time providing a common axis and mechanism to achieve an optical de-roll of the image. This complex arrangement provides a relatively large change in magnification for an all-reflective optical system than can image over 0.4-12.0 micron spectrum.

A method to maximize use of the field of view for an imaging system is provided herein. An imaging device can be part of the imaging system and include a detection unit and an alignment unit. The method includes capturing an initial image of an object and then calculating a rotational angle and zoom factor for the object in order to maximize the object's footprint within the field of view. Once the calculations are complete a computer can instruct the detection and alignment units to reconfigure their orientations relative to the object.

A variable focal length optical assembly may include a deformable entry lens element, a deformable first reflective element and a deformable second reflective element. Using a controller coupled to the deformable elements, an external force such as a mechanical, electrical, electromechanical, or electromagnetic force is applied to the deformable elements to provide any number of different focal lengths. Since the deformation of the deformable elements, and consequently the changes in focal length, occur much faster than the playback frame rate, a number of sub-frames, each containing an image obtained at a different focal length, are associated with each playback frame. The availability of multiple images in the form of sub-frames permits the selection of an optimal image for inclusion in the final playback frame sequence. The availability of multiple images in the form of sub-frames at different focal lengths also permits the seamless incorporation of zoom-in and zoom-out effects.

A reflective afocal switching assembly permits variable fields of view while at the same time providing a common axis and mechanism to achieve an optical de-roll of the image. This complex arrangement provides a relatively large change in magnification for an all-reflective optical system than can image over 0.4-12.0 micron spectrum.

A variable focal length optical assembly may include a deformable entry lens element, a deformable first reflective element and a deformable second reflective element. Using a controller coupled to the deformable elements, an external force such as a mechanical, electrical, electromechanical, or electromagnetic force is applied to the deformable elements to provide any number of different focal lengths. Since the deformation of the deformable elements, and consequently the changes in focal length, occur much faster than the playback frame rate, a number of sub-frames, each containing an image obtained at a different focal length, are associated with each playback frame. The availability of multiple images in the form of sub-frames permits the selection of an optimal image for inclusion in the final playback frame sequence. The availability of multiple images in the form of sub-frames at different focal lengths also permits the seamless incorporation of zoom-in and zoom-out effects.

A method to maximize use of the field of view for an imaging system is provided herein. An imaging device can be part of the imaging system and include a detection unit and an alignment unit. The method includes capturing an initial image of an object and then calculating a rotational angle and zoom factor for the object in order to maximize the object's footprint within the field of view. Once the calculations are complete a computer can instruct the detection and alignment units to reconfigure their orientations relative to the object.

A magnifying imaging optical unit serves for inspecting lithography masks which are used in EUV projection exposure. The imaging optical unit comprises at least two mirrors (M1 to M4) which can be displaced relative to one another for changing a magnification value. According to a further aspect, a magnifying imaging optical unit comprises at least one mirror (M1 to M4) and a magnification value, which can be changed by displacement of at least two mirrors (M1 to M4) relative to one another. Here, the magnification value can be changed between a minimum magnification value, which is greater than 100, and a maximum magnification value, which is greater than 200. An imaging optical unit emerges, which can be adapted to, in particular, mask structures with different sizes.

An optical system (e.g., a telescope) comprising an optical assembly that reflects and refracts light rays through a single window about an optical path to a detector. A field-of-view bypass assembly comprises a bypass mirror movably coupled with respect to the optical assembly. The bypass mirror is selectively translatable and tiltable between a bypass configuration and a retracted configuration. In the bypass configuration, the bypass mirror is disposed in and interrupts the primary optical path and oriented to define a secondary optical path to the detector. In the retracted configuration, the bypass mirror is both disposed out of the primary optical path and is properly shielded to prevent stray light reflections.

A reflective afocal switching assembly permits variable fields of view while at the same time providing a common axis and mechanism to achieve an optical de-roll of the image. This complex arrangement provides a relatively large change in magnification for an all-reflective optical system than can image over 0.4-12.0 micron spectrum.