Abstract: In an optical pickup (1) in which an objective lens (6) is moved in a focusing direction by the use of a focusing coil (7) and first and second magnetic circuits (8,9) coupled to the focusing coil, the first and the second magnetic circuits have a first and a second magnetic flux density, respectively. The objective lens is held by a lens holder (5) which is elastically coupled to a damper base (2) through a suspension member (3,4) to be movable in the focusing direction. The lens holder has a first part and a second part which are spaced from each other. In cooperation with the focusing coil, the first and the second magnetic circuit generate first and second force urging a first and a second part of the lens holder in the focusing direction, respectively.

Abstract: The number of light sources and the number of divided light beams are optimized, so that a light beam with sufficiently reduced speckle contrast can be used as illuminating light.

Abstract: An optical apparatus includes an optical system having optical elements, an enclosure, enclosing the optical system, for keeping a gas-tight environment inside the enclosure, and a pressure absorber which absorbs variations in differential pressure between the inside and the outside of the enclosure, while maintaining the gas-tight environment in the enclosure during at least one of transportation and storage of the optical apparatus. The optical system is one of a projection optical system and an illumination optical system of an exposure apparatus, and the inside of the enclosure is filled with one of an inert gas and a low-oxygen content gas.

Abstract: A projection and exposure apparatus includes an optical member, a holding member for holding the optical member with a gap between the optical member and the holding member, and a powder charged in the gap between the optical member and the holding member, such that the optical member and the holding member are maintained in a spaced-apart relationship.

Abstract: A manner of mounting optical elements in the front plate of an alternating traffic sign makes possible an easily-cleaned, flat or smooth outer surface and guarantees an exact alignment of all lens elements with simultaneous sealing. An optics housing is pressed into a hole of the front plate constricted by a lens element so that the hole constriction is embedded by plastic material deformation and results in a form-fit, exact, tight and permanent connection. Additionally, a tool for the precise production of the installation holes is presented.

Abstract: A device for focusing optical instruments, for example a telescope or microscope, includes a drive assembly having a fine and a coarse control knob. The knobs operatively connect with a drive shaft that extends transversely through a concave shaped support area of the drive. Seated in this support area is a tubular-shaped housing having an opening that fits over the drive shaft. Respective pairs of longitudinally spaced apart bearings then are attached to an inside wall of the housing to proximately align one each with ends of the housing shaft opening. A tubular-shaped drawtube then movably fits in the housing where a friction plate carried by a bottom portion of the drawtube engages the drive shaft. In an outer surface of the drawtube on each side of the friction plate is a longitudinal slot. Each slot has a bottom offset for a self-locating rail. Respective upper flat segments of the rails are in rolling contact with one each of the bearing pairs.