Abstract: Described is an optical waveguide having a main direction of extension, at least one radiation entrance face, and a radiation exit face that extends longitudinally to the main direction of extension, wherein at least one radiation entrance face extends transversely to the main direction of extension, and the at least one radiation entrance face has two convexly curved subregions that are connected to each other by a kink-like or concavely shaped indentation. An optical device formed with such a waveguide is also described, as is a display device.

Abstract: A projection apparatus is specified, comprising a light modulator having a light receiving region with a cross-sectional area to be illuminated of the size AM and a maximum acceptance angle ? for incident light, and at least one light source by means of which, during its operation, a light cone is produced for illuminating said cross-sectional area of said light receiving region and which comprises a number N of LED chips having a maximum radiation angle ?. At least one of the LED chips has a radiation decoupling area of the size AD. The relation 0.7·(AM·sin2(?))/(AD·sin2(?)·n2)?N?1.3·(AM·sin2(?))/(AD·sin2(?)·n2) applies, where n is equal to 1 or to the refractive index of a coupling medium with which the LED chips are provided.

Abstract: This invention relates to uniform backlighting of surfaces by semiconductor light sources. Various semiconductor light sources are combined into identical illumination groups. These identical illumination groups are arranged so that uniform backlighting of a surface is made possible. For homogeneous color mixing to be achieved, especially at edges, each illumination group in the arrangement has at least one adjacent illumination group in a different orientation.

Abstract: Described is an optical waveguide having a main direction of extension, at least one radiation entrance face, and a radiation exit face that extends longitudinally to the main direction of extension, wherein at least one radiation entrance face extends transversely to the main direction of extension, and the at least one radiation entrance face has two convexly curved subregions that are connected to each other by a kink-like or concavely shaped indentation. An optical device formed with such a waveguide is also described, as is a display device.

Abstract: This invention relates to uniform backlighting of surfaces by semiconductor light sources. Various semiconductor light sources are combined into identical illumination groups. These identical illumination groups are arranged so that uniform backlighting of a surface is made possible. For homogeneous color mixing to be achieved, especially at edges, each illumination group in the arrangement has at least one adjacent illumination group in a different orientation.

Abstract: A projection apparatus is specified, comprising a light modulator having a light receiving region with a cross-sectional area to be illuminated of the size AM and a maximum acceptance angle a for incident light, and at least one light source by means of which, during its operation, a light cone is produced for illuminating said cross-sectional area of said light receiving region and which comprises a number N of LED chips having a maximum radiation angle ?. At least one of the LED chips has a radiation decoupling area of the size AD. The relation 0.7·(AM·sin2(?))/(AD·sin2(?)·n2)?N?1.3·(AM·sin2(?))/(AD·sin2(?)·n2) applies, where n is equal to 1 or to the refractive index of a coupling medium with which the LED chips are provided.

Abstract: An input device having a first character of a first color, a second character of a second color and an illumination device which produces light of the first color and/or of the second color such that, depending on the illumination of the input device, in a first operating state only the first character of the first color, in a second operating state only the second character of the second color, or in a third operating state both characters appear.

Abstract: The invention concerns a sport goggle comprising at least one active light source for increasing the external visibility of the user.