Abstract: Photolithographic apparatus (1) including an illumination unit (3). The illumination unit (3) comprises, in this order, a radiation source unit (11), a first optical system (5) and an optical waveguide (17). The apparatus (1) further includes a second optical system (7) and a mask table (9). The apparatus (1) is adapted in such a way that both the stepper mode and the scanner mode are selectable modi, and comprises means by which the illumination unit (11), when being operative, has a slit-shaped static illumination field with a width s which is variable between smin and smax while substantially maintaining energy within the static illumination field.

Abstract: Photolithographic apparatus (1) including an illumination unit (3). The illumination unit (3) comprises, in this order, a radiation source unit (11), a first optical system (5) and an optical waveguide (17). The apparatus (1) further includes a second optical system (7) and a mask table (9). The apparatus (1) is adapted in such a way that both the stepper mode and the scanner mode are selectable modi, and comprises means by which the illumination unit (11), when being operative, has a slit-shaped static illumination field with a width s which is variable between s.sub.min and s.sub.max while substantially maintaining energy within the static illumination field.

Abstract: Illumination unit (2) for an optical system, including an illumination system (1) which comprises, in this order, a radiation source (3) and a first optical integrator (11). The illumination unit (2) further comprises a detection system (45) including a radiation-sensitive detector (47). The illumination system (1) comprises a second optical integrator (13). The two integrators (11, 13) enclose a prism system (15) comprising at least one prism (17). The prism system (15) has a coupling-out surface via which light can be coupled out of the illumination system (1), and an exit surface via which light can be coupled out of the prism system (15), without the intensity in the main light path being essentially influenced. The detection system (45) is arranged proximate to the exit surface of the prism system (15) and comprises light-integrating means.

Abstract: Picture inversion in display devices based on the twisted pneumatic effect is prevented by choosing a twist angle .phi.T such that 70.degree.<.phi.T<90.degree., and an angle .alpha. between the direction of polarization of one of the polarizers and the associated direction of orientation such that: 30.degree.+.phi.T/2<.alpha.<60.degree.+.phi.T/2.

Abstract: An imaging apparatus and an illumination unit for use in such an apparatus are described, which unit comprises an illumination housing (LH) accommodating a radiation source (LA) and at least a reflector (RL). To prevent a decrease of the radiation power supplied by the illumination housing, this housing is provided with means (LA, SH, L.sub.29) which prevent a diffuse deposit of silicon-containing particles present in the ambient air from being formed on optical components within the illumination housing.

Abstract: In a double cell the values of d..DELTA.n for both the actual cell (10) and the compensation cell (20) having opposite twist angles .phi. are chosen to be such that they are associated with different Gooch & Tarry extrema for a given wavelength. The compensation cell may then be thicker and can be obtained in a simpler manner. A universal compensation cell may alternatively be used.

Abstract: A liquid-crystal display device having an improved picture quality is obtained by rendering the iso-contrast curves rotationally symmetrical. This is obtained by means of a double cell construction, in which two identical TN-cells are present between two parallel polarizers, which TN cells are arranged relative to each other in such a manner that the director at the front face of the second cell encloses an angle of 180.degree. with the director at the front face of the first cell. A polarizer is provided between both cells, the direction of polarization of said polarizer extending perpendicularly to the direction of polarization of the two other polarizers.