Abstract: A modified Schwarzschild Casegrainian objective reflects radiant energy between the primary and secondary mirror two times to form a four reflection optical path. The four reflection optical path increases the magnification of the objective without making the working distance that separates the secondary mirror from the sample unacceptably small. The four reflection optical path maintains good image quality at high numerical aperture due, at least in part, to the relatively small size of a microscopic object. The objective functions as a zoom lens by changing the location of a remote field stop along the optical axis of the objective and refocusing because the emerging beam of radiant energy is nearly collimated along the optical axis at the field stop. The reflecting objective also obtains variable magnification by converting to a two reflection mode of operation by increasing the separation of the primary mirror from the secondary mirror from the sample image plane.

Abstract: There is disclosed a high performance lens usable in the ultraviolet region of the spectrum. It is a lens of triplet form modified by the addition of double-Gaussshells with a strong field flattening lens near the fast end.

Abstract: There is disclosed a ring field relay optical system incorporating concave spherical mirrors and including magnification achieved, at least partially, by a convex spherical mirror. In further modifications, aberrations introduced by the convex mirror are controlled by lens groups formed from fused silica. The system is usable from the visible through the deep ultraviolet portion of the spectrum.

Abstract: The present invention is directed to Optical Lithographic Systems which are particularly adapted, among many other possible uses, for use in effecting exposure of photoresist-coated semiconductor wafers, having a ring field projection system which includes at least one concave and one convex mirror arranged around an optical axis in face-to-face relationship with their centers of curvature being nearly concentric and falling on the axis, the convex mirror being smaller than and having a smaller radius of curvature than the concave mirror, an object location and a conjugate real image location, said convex mirror being positioned to reflect to the concave mirror light from the object location initially reflected from the concave mirror whereby light from the object location will be reflected at least twice at said concave mirror and at least once at the convex mirror before being focused at the image location, elements for limiting the image field to an annular zone centered about the optical axis, a first thi

Abstract: This invention is directed to a restricted off-axis field optical system having a broad spectral range, which first and second nearly concentric optical subsystems, said subsystems being constructed and arranged with respect to each other so that variation in performance of one subsystem with wavelength substantially balances that of the other. That is, the subsystems are constructed and arranged with respect to each other so that the sum of the refractive power is nearly zero and the sum of the reflective power is also nearly zero.

Abstract: Binocular stereoscopic viewers for viewing large drawings, paintings and prints, particularly those having dimensions larger than the interpupillary distance utilize two sets of nearly parallel mirrors and deviate the apparent position of the eyes inward towards the nose. Another viewer comprises a pair of prisms oriented such that the images viewed are reflected off their bases by total internal reflection. In the preferred prism viewer the apices of the prisms are hinged together in front of the nose of the viewer and the viewer may be stored with two sides together to form a prism shaped structure. In the preferred structures of both the mirror and the prism viewers, the left eye views the stereogram on the right and the right eye views the stereogram on the left and the surfaces of the device presented to the viewer are concave over the viewer's nose.

Abstract: An optical system for forming two separate images. A beamsplitter disposed in the path of a converging or diverging beam of light forms a reflected image and transmitted image. A thin positive lens disposed in the path of the transmitted beam of light selectively corrects the transmitted image for any or all of the following problems--spherical aberrations, coma, astigmatism, longitudinal and lateral color.

Abstract: These thick elements are all corrected for third order spherical aberration and they are also corrected for spherochromatism (i.e. chromatic variation of spherical aberration) or longitudinal color or both. Most are preferably made of materials of low index of refraction less than 1.55, such as BK-7 or fused silica.Most elements corrected for third order spherical and spherochromatism exhibit longitudinal color, but this poses no problem when they are used with a single wavelength laser. Such systems can be used to focus a laser beam to provide a very fast f number diffraction-limited point source, or used in optical testing, experiments, and the like. The designs are characterized by an extremely low sensitivity of performance to wavelength changes and thus to uniform temperature changes (thermal soaks). A temperature change of several hundred degrees centigrade--from cryogenic temperatures up to near the melting point of the optics, has essentially no effect on the predicted performance.

Abstract: The first element comprises a relatively thin transmissive shell concave toward the front. The second element comprises a mirror concave toward the front. The front surface of the shell may be spherical, and the rear surface aspheric, or vice versa. The central portion of the first element on either the front or back surface is mirrored to form the secondary of the system. Preferably the secondary mirror is on the front of the first element. In one embodiment the second element is also a transmissive shell. In one form of this embodiment the second transmissive shell is aspheric on the front and spherical on the back. In another form it is spherical on the front and aspheric on the back. In both of these forms the primary mirror is located on the back of the second element. In another embodiment the second transmissive element is aspheric on the front and flat on the back; the front surface being mirrored except for the central portion thereof, through which light from the secondary is focused.

Abstract: The systems comprise a transmissive shell and a mirror. The surfaces of the shell and the mirror are monocentric; that is, spherical and have the same center of curvature. Both the object and image planes are located in front of and spaced away from the transmissive shell.Single optical element systems comprise a transmissive shell with the mirror and the back surface of the shell being coincidence. These elements may be used as laser beam focusers, beam divergers and collimators.Unit relay systems for use in super accurate microcircuit printing are disclosed. Parameters are given for a monochromatic diffraction limited f/2 system in the ultraviolet.A single element monocentric catadiotric system is disclosed, which is corrected for 3rd and 5th order spherical aberration and all field aberrations except Petzval curvature. A two-element version can cover very wide fields of view with good performance at speeds as fast as f/0.6.

Abstract: The radii of two concave and two convex mirrors have the same absolute value. The two concave mirrors are placed back to back and have a central aperture. The two convex mirrors face the concave mirrors and also have a central aperture. An image at the apex of one of the convex mirrors will be imaged at unit magnification at the vertex of the other convex mirror if the spacing between the concave and convex mirrors is 0.866 times the absolute value of their radius. This system is corrected for all aberrations except astigmatism. Astigmatism is corrected by a double convex thin lens at the intermediate image at the vertices of the concave mirrors. Petzval curvature introduced by the field lens may be corrected by plano-concave lenses near the object and image planes. Alternatively identical shell lenses may be placed on either side of the intermediate image to correct for both astigmatism and Petzval curvature. The lenses may be achromatic doublets to correct for chromatic variation of field aberrations.

Abstract: A telescope made only of spherical mirrors including a first mirror system comprising a first, concave spherical mirror and a second, convex spherical mirror have a common center of curvature, the ratio of the radius of said first, concave mirror to said second convex mirror being approximately .sqroot.5+1:.sqroot.

Abstract: An inexpensive laser beam expander including a first mirror system comprising an off axis section of a Schwarzschild telescope system with a first, convex spherical mirror and a second, concave spherical mirror, having a first common center of curvature, the input laser beam being incident on the first mirror and reflected therefrom to the second mirror, the second mirror forming a real image at a first image point; and a second mirror system comprising a backwards Schwarzschild telescope system including a third, convex mirror and a fourth, concave mirror, having a second common center of curvature, the second system being such that parallel incident light striking the fourth concave mirror and reflected to the third convex mirror will form a virtual image behind the third convex mirror at a second image point, the second system disposed so that the second image point coincides with the first image point whereby the third convex mirror intersects the light reflected from the second concave mirror and reflect

Abstract: A laser optical system which includes a mirror system for forming a mirror cavity, a laser target disposed in this cavity, a plurality of focused laser beams directed into the cavity, and the mirror system being so arranged that each of the laser beams is reflected off the walls of the cavity a plurality of times prior to being focused on the laser target to thereby heat the target to a very high temperature.