In a method for three-dimensionally measuring a 3D aerial image in the region around an image plane during the imaging of a lithography mask, which is arranged in an object plane, a selectable imaging scale ratio in mutually perpendicular directions (x, y) is taken into account. For this purpose, an electromagnetic wavefront of imaging light is reconstructed after interaction thereof with the lithography mask. An influencing variable that corresponds to the imaging scale ratio is included. Finally, the 3D aerial image measured with the inclusion of the influencing variable is output. This results in a measuring method with which lithography masks that are optimized for being used with an anamorphic projection optical unit during projection exposure can also be measured.

An illumination system for an optical arrangement such as an EUV lithography apparatus, having: at least one optical element which has at least one optical surface, on which a coating which reflects illumination radiation is applied, and an actuator device aligning the optical surface in at least two angular positions in the radiation path. The coating either has a thickness (d.sub.OPT1) at which a mean value ((R.sub.1+R.sub.2)) formed from a thickness-dependent reflectivity (R.sub.1, R.sub.2) of the coating at the at least two angular positions is maximized or has a thickness (d.sub.OPT2) at which a maximum change (max(R.sub.1/R.sub.1, R.sub.2/R.sub.2)) in the reflectivity (R.sub.1, R.sub.2) caused by a thickness tolerance of the coating is minimized at the respective angular positions or else the reflecting coating has a thickness (d.sub.O2) at which the reflectivity (R.sub.1, R.sub.2) of the coating has the same magnitude in the at least two angular positions.

A head-up display is configured to project an image on a transparent reflection member to cause an observer to visually recognize a virtual image, and includes a display device configured to display the image, and a projection optical system configured to project the image displayed by the display device as the virtual image for the observer. The projection optical system is configured to form the image as an intermediate image, and includes a first optical element configured to condense light, a first lens configured to condense light, and a second optical element configured to diffuse light. The first optical element, the first lens, and the second optical element are disposed in this order along an optical path from the display device.

In a method for three-dimensionally measuring a 3D aerial image in the region around an image plane during the imaging of a lithography mask, which is arranged in an object plane, a selectable imaging scale ratio in mutually perpendicular directions (x, y) is taken into account. For this purpose, an electromagnetic wavefront of imaging light is reconstructed after interaction thereof with the lithography mask. An influencing variable that corresponds to the imaging scale ratio is included. Finally, the 3D aerial image measured with the inclusion of the influencing variable is output. This results in a measuring method with which lithography masks that are optimized for being used with an anamorphic projection optical unit during projection exposure can also be measured.

A spectrograph that includes camera focusing optics with a primary mirror having a concave-shaped reflective mirror surface, a secondary mirror having a convex-shaped reflective mirror surface and positioned to receive light reflected by the primary mirror, a tertiary mirror having a concave reflective mirror surface and positioned to receive light reflected by the secondary mirror, and a field correcting lens comprising a convex lens surface in combination with a concave lens surface, wherein light received by said field correcting lens from said tertiary mirror enters said convex lens surface, traverses said field correcting lens, and exits from said concave lens surface. The optional field correcting lens is positioned such that the primary mirror, secondary mirror, tertiary mirror, and the field correcting lens share the common parent vertex axis.

Disclosed systems and methods for the remote detection of atmospheric gas may include (1) receiving, at a collector, thermal infrared energy from at least one atmospheric column, (2) receiving, at optical subsystems, the thermal infrared energy over optical paths, (3) focusing the thermal infrared energy onto diffraction gratings that disperse the thermal infrared energy at a wavelength within a mid-wavelength infrared (MWIR) spectral region and a wavelength within a long-wavelength infrared (LWIR) spectral region, (4) receiving, at detectors, the thermal infrared energy dispersed from the diffraction gratings within the MWIR spectral region and the LWIR spectral region, (5) determining spectral component data associated with the thermal infrared energy in the MWIR spectral region and the LWIR spectral region, (6) sending the spectral component data to a computing device, and (7) identifying an atmospheric gas based on the spectral component data.

A head-up display that allows an observer to visually recognize a virtual image in a viewpoint region of the observer is provided. The head-up display includes: a display device that has a display surface and displays an image on the display surface; and a first optical system that has a concave mirror, and a lens condensing the light and disposed between the concave mirror and the display surface. The first optical system causes a beam exiting from the display surface to form an intermediate image via the lens and the concave mirror, the intermediate image being enlarged from the image displayed on the display surface.

A light guide member includes three surfaces of a second surface, a fourth surface, and a fifth surface as two or more non-axisymmetric curved surfaces, and a projection lens includes a lens surface as a non-axisymmetric aspheric surface. With this, on the light guide member side, even when there is a shape constraint that the first surface or the third surface which is a surface contributing to light guide is a flat surface, and correction of asymmetric aberration is limited, it becomes possible to perform sufficient aberration correction as the whole of an optical system including the projection lens. Therefore, the virtual image display apparatus can have a wide viewing angle and high performance, and can be made small and lightweight.

A head-up display is configured to project an image on a transparent reflection member to cause an observer to visually recognize a virtual image, and includes a display device configured to display the image, and a projection optical system configured to project the image displayed by the display device as the virtual image for the observer. The projection optical system is configured to form the image as an intermediate image, and includes a first optical element configured to condense light, a first lens configured to condense light, and a second optical element configured to diffuse light. The first optical element, the first lens, and the second optical element are disposed in this order along an optical path from the display device.

The image display apparatus includes an optical system causing a light flux entering from an original image by being transmitted through a fifth surface to reflect at a fourth surface, a third surface, a first surface and a second surface and then cause the light flux to be transmitted through the first surface and exit toward an exit pupil, causing the light flux to form an intermediate image and causing optical paths to intersect with each other. The optical system satisfies 0.62L12/f5.00 and 1.80L45/L125.00. When a distance between hit points of a central-view-angle principal ray on the surfaces is referred to as a hit point distance, L45 represents a hit point distance between the fourth and fifth surfaces, L12 represents a hit point distance between the first and second surfaces, and f represents a focal length of the optical system.