Abstract: An optical element which can be utilized in various versions and implementations of switchable light filters having, in addition, polarization filters and/or other means for varying the polarization characteristics of light, for example, liquid crystal layers. A combination of switchable light filter and imaging display device makes possible a private viewing effect that can be switched on and off. The optical element comprises a first layer or a first layer and a plurality of further layers, each layer including a material with a plurality of light-absorbing transition dipole moments. At least in a first state, each transition dipole moment is oriented, with a tolerance of 10° at the maximum, parallel to a selectable preferential direction or fluctuates around it so that light which is incident in the optical element is transmitted or at least partially absorbed depending on its incident direction.

Abstract: A method for influencing light propagation directions of a light-emitting surface emitting light of a first wavelength range in a first direction and light of a second and wavelength range in a second direction. The wavelength ranges have a wavelength-dependent spectral radiance and differ in a peak wavelength. A switchable color converter is arranged in front of the light-emitting surface. The method includes the steps of a) deactivating the color converter for a first mode so that the second-wavelength range is transmitted and the first-wavelength range is absorbed, such that light from the light-emitting surface is only perceptible from the second direction, or b) activating the color converter for a second mode so that light of the first-wavelength range is converted into light of the second-wavelength range and light of the second-wavelength range is transmitted, such that light from the light-emitting surface is perceptible from both directions.

Abstract: A two-dimensionally extensive optical element having a light entry side and a light exit side. The optical element includes alternating transparent first regions and second regions having materials with different first refractive indices and second refractive indices. The first refractive index is higher than the second refractive index. First layers and second layers which are opaque or are switchable to be opaque are arranged at the light entry surfaces and light exit surfaces of the second regions. When the layers are opaque, the propagation directions of light passing through the optical element are limited compared to layers which are switched to be transparent.

Abstract: An optical element including a plate-shaped substrate with a light-entrance surface and a light-exit surface, a multiplicity of imaging elements formed on the light-exit surface and a multiplicity of diaphragms formed on the light-entrance surface. Each diaphragm includes a transparent geometric region in an opaque region. The optical element can be switched between two operating modes B1 and B2 such that some of the imaging elements change their focal length between values f1 and f2 and/or, some of the diaphragms change their aperture width and/or their position. Exactly one diaphragm is associated with each imaging element in mode B1 so that light passing through the diaphragm is imaged or collimated by the associated imaging element. Consequently, light arriving in the optical element through the diaphragms and then through the light-entrance surface has, after passing through the associated imaging elements in the two operating modes B1 and B2, different propagation angles.

Abstract: A method for influencing light propagation directions of a light-emitting surface emitting light of a first wavelength range in a first direction and light of a second and wavelength range in a second direction. The wavelength ranges have a wavelength-dependent spectral radiance and differ in a peak wavelength. A switchable color converter is arranged in front of the light-emitting surface. The method includes the steps of a) deactivating the color converter for a first mode so that the second-wavelength range is transmitted and the first-wavelength range is absorbed, such that light from the light-emitting surface is only perceptible from the second direction, or b) activating the color converter for a second mode so that light of the first-wavelength range is converted into light of the second-wavelength range and light of the second-wavelength range is transmitted, such that light from the light-emitting surface is perceptible from both directions.

Abstract: An optical element which can be utilized in various versions and implementations of switchable light filters having, in addition, polarization filters and/or other means for varying the polarization characteristics of light, for example, liquid crystal layers. A combination of switchable light filter and imaging display device makes possible a private viewing effect that can be switched on and off. The optical element comprises a first layer or a first layer and a plurality of further layers, each layer including a material with a plurality of light-absorbing transition dipole moments. At least in a first state, each transition dipole moment is oriented, with a tolerance of 10° at the maximum, parallel to a selectable preferential direction or fluctuates around it so that light which is incident in the optical element is transmitted or at least partially absorbed depending on its incident direction.

Abstract: An optical element including a plate-shaped substrate with a light-entrance surface and a light-exit surface, a multiplicity of imaging elements formed on the light-exit surface and a multiplicity of diaphragms formed on the light-entrance surface. Each diaphragm includes a transparent geometric region in an opaque region. The optical element can be switched between two operating modes B1 and B2 such that some of the imaging elements change their focal length between values f1 and f2 and/or, some of the diaphragms change their aperture width and/or their position. Exactly one diaphragm is associated with each imaging element in mode B1 so that light passing through the diaphragm is imaged or collimated by the associated imaging element. Consequently, light arriving in the optical element through the diaphragms and then through the light-entrance surface has, after passing through the associated imaging elements in the two operating modes B1 and B2, different propagation angles.

Abstract: A method for influencing light propagation directions of a plurality of illuminated surfaces, comprising: arranging switchable absorbers on the light-exit side of the surfaces, such that light only exits through portions of the surfaces which are in front of the surfaces; switching on the absorbers for a first operating state so that a portion of the light emanating from the surfaces is absorbed, while the rest of the light exits at the surface portions of the light-exit side of the surface substrates at which no switchable absorbers are applied, resulting in light only being visible from a limited viewing angle which is defined by the shape of the switchable absorber, the shape of the surface, refractive index conditions in, and thickness of, the substrates of the surfaces; and switching off the absorbers for a second operating state so that light from the surfaces is visible from an unrestricted viewing angle.

Abstract: An illuminating apparatus designed for a display screen and operable in at least two operating modes B1 and B2 and/or at least one operating mode B3 for illuminating separately two or simultaneously both, at least partially disjoint angular ranges W1 and W2, comprising a planar backlight unit, which in a first alternative radiates light into the said restricted angular range W2, and in a second alternative radiates light into a restricted angular range W2a, a plate-shaped light guide that is arranged in front of the backlight unit and features, on at least one of the large surfaces and/or within its volume, outcoupling elements, wherein the light guide is transparent to at least 70% of the light originating from the backlight unit, and light sources are arranged laterally on at least one of the narrow edges of the light guide.

Abstract: An illuminating apparatus designed for a display screen and operable in at least two operating modes B1 and B2 and/or at least one operating mode B3 for illuminating separately two or simultaneously both, at least partially disjoint angular ranges W1 and W2, comprising a planar backlight unit, which in a first alternative radiates light into the said restricted angular range W2, and in a second alternative radiates light into a restricted angular range W2a, a plate-shaped light guide that is arranged in front of the backlight unit and features, on at least one of the large surfaces and/or within its volume, outcoupling elements, wherein the light guide is transparent to at least 70% of the light originating from the backlight unit, and light sources are arranged laterally on at least one of the narrow edges of the light guide.

Abstract: A method for manipulation of image data for a display screen that can be operated in two operating modes, viz B1 for a free viewing mode and B2 for a restricted viewing mode, comprising: a) switching on the operating mode B2, b) monitoring the eye position of a viewer in a given angular range A, with a signal S being set if the eye position signifies that the viewer is looking at the screen, and being deleted if not looking at the screen, c) manipulating the image data with regard to image parameters, wherein the said manipulation i) is performed to the effect that the quality of the restricted viewing mode B2 is enhanced, ii) is dynamically implemented in a control unit of the display screen, and iii) is performed exclusively while the signal S remains set, and d) repeating steps b) and c) until operating mode B2 concluded.

Abstract: A method for presenting image content in two operating modes, B1 for a viewing mode with a restricted viewing angle, and B2 for a viewing mode with an unrestricted viewing angle, comprising: providing a first image generator radiating image content into a restricted viewing angle; providing a second image generator radiating image content into an unrestricted viewing angle, wherein the second generator is in front of the first, and is partially transparent to light from the first, and deflects, on at least 50% of its surface, at least 90% of the light passed by it, by maximally 10°; switching on the first generator to start mode B1, wherein the second generator is switched to a transparent state and scatters only a negligible portion of light from the first generator, to retain the restricted viewing angle; and switching on the second generator to start mode B2.

Abstract: A method for checking an operating mode of a display screen switchable between a free-viewing operating mode B1 and a restricted-viewing operating mode B2, comprising: in operating mode B2, determining a brightness value H of a surface and/or edge of a transparent light guide; then, depending on the brightness value H: i) unchanged use of operating mode B2 if the brightness value lies within a range of specified Hg values; ii) switching off operating mode B2 if the brightness value lies within a range of specified Hs values; or iii) changed use of operating mode B2 if the brightness value lies within a range of specified Hm values, with the control unit exerting an influence on the image content perceptible on the display screen by reducing the latter's brightness and/or contrast, with the range Hm lying between the ranges Hs and Hg, and with the ranges bordering on each other.

Abstract: An optical element comprising a planar substrate with a first large surface functioning as a light-entrance surface, and a second large surface functioning as a light-exit surface. The optical element further comprises a liquid or skeleton matrix arranged between the first and second large surface, and electrophoretically or magnetophoretically movable particles that interact with light of one or several wavelengths or wavelength ranges.

Abstract: A method for manipulation of image data for a display screen that can be operated in two operating modes, viz B1 for a free viewing mode and B2 for a restricted viewing mode, comprising: a) switching on the operating mode B2, b) monitoring the eye position of a viewer in a given angular range A, with a signal S being set if the eye position signifies that the viewer is looking at the screen, and being deleted if not looking at the screen, c) manipulating the image data with regard to image parameters, wherein the said manipulation i) is performed to the effect that the quality of the restricted viewing mode B2 is enhanced, ii) is dynamically implemented in a control unit of the display screen, and iii) is performed exclusively while the signal S remains set, and d) repeating steps b) and c) until operating mode B2 concluded.

Abstract: A method for presenting image content in two operating modes, B1 for a viewing mode with a restricted viewing angle, and B2 for a viewing mode with an unrestricted viewing angle, comprising: providing a first image generator radiating image content into a restricted viewing angle; providing a second image generator radiating image content into an unrestricted viewing angle, wherein the second generator is in front of the first, and is partially transparent to light from the first, and deflects, on at least 50% of its surface, at least 90% of the light passed by it, by maximally 10°; switching on the first generator to start mode B1, wherein the second generator is switched to a transparent state and scatters only a negligible portion of light from the first generator, to retain the restricted viewing angle; and switching on the second generator to start mode B2.

Abstract: An illuminating apparatus for a display screen with a transmissive image generator, having a free-viewing mode and a restricted-viewing mode, comprising a background illuminator radiating light in a wide angular range, a plate-shaped light guide in front of the background illuminator with outcoupling elements, and light sources. Outcoupling element dimensions are smaller than the width and height of subpixels of the image generator, parts of the surface of two outcoupling elements are below each subpixel and the filling factor of the outcoupling elements is maximally 50% of the large surface of the light guide, and at least 80% of the light coupled out is radiated within an angular range of 60°, and more than 50% of the light is radiated away from or toward the background illuminator, and in the restricted mode, the background illuminator and light sources are off, and in the free-viewing mode, the background illuminator is on.

Abstract: A method for checking an operating mode of a display screen switchable between a free-viewing operating mode B1 and a restricted-viewing operating mode B2, comprising: in operating mode B2, determining a brightness value H of a surface and/or edge of a transparent light guide; then, depending on the brightness value H: i) unchanged use of operating mode B2 if the brightness value lies within a range of specified Hg values; ii) switching off operating mode B2 if the brightness value lies within a range of specified Hs values; or iii) changed use of operating mode B2 if the brightness value lies within a range of specified Hm values, with the control unit exerting an influence on the image content perceptible on the display screen by reducing the latter's brightness and/or contrast, with the range Hm lying between the ranges Hs and Hg, and with the ranges bordering on each other.

Abstract: A screen with a transmissive image generator with pixels which is operable in at least two operating modes, B1 for a free viewing mode and B2 for a restricted viewing mode, and with an illuminating apparatus comprising a backlight that has a planar extension and radiates light in a restricted angular range, a plate-shaped light guide arranged in front of the backlight and provided with outcoupling elements on one of the large surfaces and/or within its volume, the light guide being transparent to at least 70% of the light emitted by the backlight; and light sources arranged laterally at edges of the light guide. In mode B2, the backlight is switched on and the light sources are switched off, and in mode B1 at least the light sources are switched on. In interaction with the transmissive image generator the illuminating apparatus constitutes an advantageous screen permitting the operating modes.

Abstract: A screen with a transmissive image generator with pixels which is operable in at least two operating modes, B1 for a free viewing mode and B2 for a restricted viewing mode, and with an illuminating apparatus comprising a backlight that has a planar extension and radiates light in a restricted angular range, a plate-shaped light guide arranged in front of the backlight and provided with outcoupling elements on one of the large surfaces and/or within its volume, the light guide being transparent to at least 70% of the light emitted by the backlight; and light sources arranged laterally at edges of the light guide. In mode B2, the backlight is switched on and the light sources are switched off, and in mode B1 at least the light sources are switched on. In interaction with the transmissive image generator the illuminating apparatus constitutes an advantageous screen permitting the operating modes.