Method and structure for influencing the direction of light propagation

Abstract

The present invention relates to a method for influencing the light propagation direction of a plurality of adjacent self-luminous and / or illuminated surfaces (F1, F2, ...), which surfaces comprise their own or a common transparent substrate (1) on the light exit side, and the substrate is arranged above the luminescent layer of the self-luminous or illuminated surface (F1, F2, ...), the method comprising the steps of: a) arranging switchable absorbers (2) on the light exit side on one or more partial surfaces of the corresponding substrate (1) having at least a plurality of surfaces (F1, F2, ...), wherein the spatial main propagation direction of these switchable absorbers (2) is arranged parallel to the light exit surface of one or more substrates (1) without taking into account tolerances; b) limiting the light propagation of light emitted from each individual surface (F1, F2, ...) so that the light from the surface (F1, F2, ...) does not pass through the substrate (1) or does not pass through the part of the substrate (1) that is located in front of another surface in the case of parallel projection, but only passes through the part that is located only in the observed area in the case of parallel projection. c) in a first operating state B1, the absorption effect of the switchable absorber (2) is turned on, so that a part of the light emitted from the surface (F1, F2, ...) is absorbed, and the remaining light is emitted unimpeded on the surface portion of the light exit side of the substrate (1) on which the switchable absorber (2) is not applied, whereby the light from the corresponding surface (F1, F2, ...) is only visible from a restricted viewing angle, in particular, the viewing angle is limited by the geometry of the switchable absorber (2), the geometry of the corresponding surface (F1, F2, ...), the refractive index relationship in the structure and the thickness of the substrate (1); d) in a second operating state B2, the absorption effect of the switchable absorber (2) is turned off, so that the light emitted from the surface (F1, F2, ...) can propagate through the surface unimpeded without taking into account the residual absorption loss of the switchable absorber (2), whereby the light from the corresponding surface (F1, F2, ...) can be visible from an unrestricted viewing angle. The invention also relates to a corresponding structure.

Description

Technical Field

[0001] In recent years, great progress has been made in extending the viewing angles of LCDs and OLEDs. However, there are often situations where such a very large viewing area of ​​the screen can become a disadvantage. Various information, such as banking data or other personal details and sensitive data, is also increasingly available on mobile devices such as laptops, mobile phones and tablets. As a result, people need to monitor who is allowed to see this sensitive data; people need to be able to choose between wide viewing angles in order to share the information on their display with others, for example when viewing holiday photos or for advertising purposes. On the other hand, if people want to keep the image information confidential, a small viewing angle is desired.

[0002] A similar problem arises in vehicle construction: When the engine is started, the driver must not be distracted by image content such as digital entertainment, while passengers want to watch this content while riding. Therefore, a screen is required that can switch between the corresponding display modes. Background Art

[0003] Additional films based on micro-thin layers are already used in mobile displays for their visual data protection. However, these films cannot be changed (switched) and the film always has to be applied manually and then removed again. When one does not need the film anymore, the film also has to be separated from the display. In addition, a significant disadvantage of using such layered films is related to the associated light losses.

[0004] Patent document US5,956,107A discloses a switchable light source, with which the screen can be operated in multiple modes. The disadvantage is that all light coupling is based on scattering, so only low efficiency and non-optimal light direction effects can be achieved. In particular, the realization of a focused light cone is not disclosed in detail.

[0005] CN107734118A introduces a screen that uses two backlights to make the viewing angle of the screen controllable. To this end, the upper backlight of the two backlights should emit focused light. A grille with opaque and transparent parts is specifically mentioned as a design solution for this. However, this may mean that the light from the second backlight (which must penetrate the first backlight in the direction toward the LCD panel) is also focused, and in fact, a common viewing mode that should be set for a wide viewing angle will experience a significant angle narrowing.

[0006] US 2007 / 030240 A1 describes an optical element for controlling the light propagation direction of light originating from a backlight. Such an optical element requires liquid crystals in the form of PDLC, for example, which are expensive on the one hand and safety is critical, especially for end-customer applications, because PDLC liquid crystals generally require voltages higher than 60V for their circuits.

[0007] In CN1987606A, a screen is again introduced, which makes the viewing angle of the screen controllable by means of two backlights. In particular, a "first light plate" is used here which must be wedge-shaped in order to achieve the desired focused light coupling. The exact details of achieving focused light coupling at the appropriate angle conditions are not disclosed.

[0008] In addition, US2018 / 0267344A1 introduces a structure with two planar lighting modules. Here, the light from the lighting module placed behind in the viewing direction is focused by a separate structure. After focusing, the light still needs to pass through the front lighting module with a diffuser. Therefore, strong light focusing of the screen for viewing protection cannot be optimally achieved.

[0009] Finally, US 2007 / 0008456 A1 discloses dividing the light exit angle into at least three regions, two of which are usually exposed to light. It follows that a screen for viewing protection using a display illuminated in this way cannot be viewed from only one direction.

[0010] The above methods and structures generally have the common disadvantage that they significantly reduce the brightness of the basic screen and / or require active, at least dedicated optical elements for mode switching and / or require complex and expensive production and / or reduce the resolution in free viewing mode and / or only allow weaker viewing protection. Summary of the invention

[0011] The object of the invention is therefore to introduce a method and a structure for influencing the direction of light propagation which should be cost-effective and suitable for mass production and generally applicable, in particular, to OLED screens but also to other screen types, in order to be able to switch between a viewing protection mode and a free viewing mode without substantially reducing the resolution of such screens.

[0012] According to the invention, this object is achieved by a method for influencing the light propagation direction of a plurality of adjacent self-luminous and / or illuminated surfaces (F1, F2, ...), which surfaces comprise a transparent substrate on the light exit side. In a first alternative, each surface has its own substrate, or in a second alternative, a plurality or all surfaces (F1, F2, ...) use a common substrate. In this case, the substrate is arranged above the luminous layer of the self-luminous or illuminated surface (F1, F2, ...), but not necessarily directly above the luminous layer. Starting from this, the method according to the invention comprises the following steps:

[0013] For at least a plurality of faces (F1, F2, . . . ), a switchable absorber is arranged on the light exit side in each case on one or more partial faces of the corresponding substrate in a first alternative or on one or more partial faces of a common substrate in a second alternative, the spatial main propagation direction of the switchable absorber being arranged parallel to the light exit face of the substrate, ignoring a tolerance of a maximum of 10°,

[0014] limiting the light propagation of the light emanating from each individual facet (F1, F2, ...) so that the light from a facet (F1, F2, ...) does not emerge through the substrate or through a portion of the substrate that is situated in front of another facet in parallel projection, but rather emerges only through a portion of the substrate that is situated in front of the observed facet in parallel projection,

[0015] For a first operating state B1, the absorption effect of the switchable absorber is switched on, so that a portion of the light emitted from the surface (F1, F2, ...) is absorbed, while the remaining light is emitted unhindered on the surface portion of the light exit side of the substrate on which the switchable absorber is not applied, whereby the light from the corresponding surface (F1, F2, ...) is only visible from a restricted viewing angle, which is defined in particular by the geometry of the switchable absorber, the geometry of the corresponding surface (F1, F2, ...), the refractive index relationship in the structure and the thickness of the substrate,

[0016] For the second operating state B2, the absorption effect of the switchable absorber is turned off so that the light emitted from the surfaces (F1, F2, ...) can propagate through the absorber unimpeded, ignoring the residual absorption losses of the switchable absorber, so that the light from the corresponding surfaces (F1, F2, ...) can be visible from an unrestricted viewing angle (but at least from a viewing angle larger than that in the operating state B1).

[0017] In the first variant and all subsequent variants of the invention, a restricted viewing angle does not necessarily mean that no light emerges at all in certain directions. Rather, a certain residual light may still emerge there, but this residual light may impede viewing comfort. Even in areas where visibility should be limited, typical values ​​for such residual light (measured in brightness) are a few percent of the peak value (which can be perceived to the greatest extent from the dedicated area of ​​the restricted viewing angle), typically 1% to 5% at most.

[0018] In a first alternative, each face (F1, F2, ...) comprises its own substrate (i.e. 1.1, 1.2, 1.3, etc.). These substrates are then preferably arranged essentially in one plane. In contrast, in a second alternative, all faces (F1, F2, ...) can also comprise a common, planarly extending substrate. In addition, a plurality of face clusters (F1, F2, ...) can each comprise a substrate, and then there are a plurality of substrates.

[0019] In particular, the switchable absorbers corresponding to all surfaces (F1, F2, . . . ) can be switched simultaneously when the entire surface is switched between operating states B1 and B2, or only parts of the surface are switched between operating states B1 and B2 in such a way that only a proper subset of the switchable absorbers is switched.

[0020] For example, the common substrate or the separate substrates can be considered as transparent spacers made of glass or polymer. At the same time, such a substrate can also be a component of an image generator, such as a substrate of an OLED pixel or an OLED panel, or a substrate of an LCD panel. However, if there are separate substrates, such as an OLED or LCD panel, the substrate introduced in the present invention is the common substrate or the separate substrate is an additional optical layer. Typically, the substrate used in the present invention has a thickness that can range from a few microns to about one millimeter or several millimeters depending on the design.

[0021] For example, by arranging the permanent or switchable absorption layer between separate substrates in a first alternative or in a common substrate in a second alternative, a limitation of the light propagation of light emitted from each individual face (F1, F2, ...) can be achieved, wherein the planes in which the switchable absorber is arranged and in which the absorption layer is arranged are preferably arranged perpendicular to each other, ignoring a tolerance of a maximum of 25 degrees.

[0022] Alternatively, it is conceivable that the light propagation of the light emitted from each individual face (F1, F2, ...) is restricted by choosing the refractive index relationship of the substrate relative to air in such a way that the unwanted light beams are converted into total reflection towards the respective adjacent facets and are therefore eliminated in the basic design to achieve light balance. In practice, absorbers are then usually mounted on the narrow sides of the substrate to absorb this light.

[0023] In another embodiment of the present invention, a collimating lens is provided on the substrate or on a facet of the substrate on which the switchable absorber is not applied, so as to achieve further light beam focusing and better limit the viewing angle.

[0024] For example, each switchable absorber can include an electrochromic layer and / or a liquid crystal layer and / or a layer based on electrophoresis and / or a layer based on electrowetting with absorbent particles and / or an opaque-to-transparent PDLC layer (“Polymer dispersed liquid crystal”), which can each be controlled by an electric field.

[0025] In another alternative, each switchable absorber can include a switchable filter, which absorbs a color spectrum of colors emitted by a surface (F1, F2, ...) below it in a first state and transmits the color spectrum in a second state, wherein the switchable filter can be controlled by an electric field in dependence on its state.

[0026] Each switchable absorber preferably has the geometry of a pinhole. The pinhole can be, for example, circular, polygonal, in particular rectangular. The dimensions of the switchable absorber in terms of its area are usually about 25% to 90% of the self-luminous or illuminated surface (F1, F2, ...). In absolute numbers, depending on the design of the surface (F1, F2, ...), this dimension will be a few tens of square micrometers to a few square millimeters or even square centimeters. Other designs are conceivable.

[0027] For the special design of the invention, reverse pinhole geometries are also possible. In the case of such reverse pinholes, in contrast to non-reverse pinholes, those otherwise uncovered facets or regions of the substrate are covered with a switchable absorber, or the already covered facets or regions of the substrate are not covered with a switchable absorber.

[0028] The method according to the invention is of particular practical significance when there are a plurality of self-luminous surfaces (F1, F2, ...), each of which has a minimum pixel (monochrome / single color, such as red, green or blue, or full color) or a minimum pixel cluster of an OLED screen, a mini-LED screen, a VCSEL screen, a QLED screen, an LED screen or a micro-LED screen, so that such a screen can be switched between an operating state B1 for a restricted viewing angle and an operating state B2 for an unlimited viewing angle. In other words, a plurality of self-luminous or illuminated surfaces (F1, F2, ...) as a whole form the screen.

[0029] In the case of a minimum pixel cluster as a self-luminous or illuminated surface F1, F2, ..., it is also conceivable that one or more pixels are divided into different, adjacent clusters of this type within their surface. In other words, two self-luminous or illuminated surfaces F1, F2, ... can also share a minimum pixel of the screen. This is particularly meaningful when the method according to the invention is applied to a finished screen panel, for example to an OLED panel or LCD panel, so that the substrate with the switchable absorber is only installed afterwards.

[0030] Screen technology can generally involve self-luminous or illuminated screens, such as LCD, SED, FED or other screens. In the case of LCD panels, they are usually backlit by a planar, controllable light source. However, in this case, so-called "direct backlighting" can also be used, which can achieve locally different illumination levels. In this case, a cluster of pixels is illuminated by individually controllable LEDs. The method according to the invention can also be used here.

[0031] Furthermore, a planar light source, such as an LCD backlight (direct backlight or fully controllable backlight) can be divided into individual surfaces F1, F2, ... (e.g. vertical stripes or a two-dimensional grid) or consist of self-luminous or illuminated surfaces F1, F2, ... so that the method according to the invention can be implemented on these surfaces. This results in a backlight that emits light with a restricted viewing angle or an unrestricted viewing angle. If such a backlight is used behind an LCD panel in the viewing direction, the LCD panel can be switched between an operating state B1 for a restricted viewing angle and an operating state B2 for an unrestricted viewing angle.

[0032] Therefore, the present invention also includes using a planar light source composed of self-luminous or illuminated surfaces (F1, F2, . . .) to backlight the LCD panel, whereby the LCD panel operates in a first operating state B1 corresponding to a limited viewing angle and in an operating state B2 for an unlimited viewing angle.

[0033] In another advantageous design, each switchable absorber has the geometry of a pinhole. Here, the pinholes can be advantageously arranged on a common substrate or one or more sub-surfaces of the corresponding substrate, depending on the application, so that the geometric center of gravity of the self-luminous or illuminated surface F1, F2, ... and the geometric center of gravity of the surface portion not covered by the switchable absorber do not coincide with each other in parallel projection, at least for a portion of the surfaces F1, F2, ... . It can thus be achieved that the restricted light propagation direction of each surface F1, F2, ... is variable, and it is particularly advantageous that, when the surface F1, F2, ... is observed by an observer, the surface F1, F2, ... radiates or emits light to the right (i.e., toward the observer) on the left, and radiates or emits light to the left (i.e., again toward the observer) on the right. In this way, improved uniformity can be achieved despite the restricted light direction.

[0034] In a further embodiment, each switchable absorber has the geometry of a reverse pinhole. As described above, for such a reverse pinhole, those facets or areas of the substrate that are otherwise uncovered are covered with the switchable absorber, or the already covered facets or areas of the substrate are not covered with the switchable absorber, compared to a non-reverse pinhole.

[0035] Therefore, in this design, in which the switchable absorber is arranged essentially opposite the self-luminous or illuminated surface F1, an operating state B1 for the restricted mode is generated. The light emitted from the surface F1 is now absorbed by the switchable absorber. However, the light beam that is totally reflected inside the substrate is still spatially close to the absorber inside the substrate. In addition, a microstructured decoupling element is arranged on the facet not covered by the absorber, which decouples the above-mentioned internally totally reflected light beam from the common substrate or the corresponding substrate by changing its direction, wherein the light decoupled by the microstructured decoupling element is only visible from a restricted viewing angle.

[0036] If, however, the configuration is switched to operating state B2 , ie if the absorber is switched to transparent, due to the decoupling element the light not only reaches the observer but also, without taking into account technically determined losses, the light from the surface F1 now passes directly through the absorber.

[0037] Finally, the invention can be further improved by providing permanent scattering microstructures on the switchable absorber. The use of permanent scattering microstructures on the switchable absorber represents a reliable means for all embodiments of the invention in order to optimize the light distribution in particular for the operating state B2.

[0038] In the operating state B1 , the scattering microstructure is inactive since the absorber there is switched to an absorbing effect, so that virtually no or almost no light from the surface F1 reaches the scattering microstructure.

[0039] In contrast, in operating state B2, the switchable absorber is switched to transparent and the scattering microstructure scatters light that may also reach the switchable absorber directly from surface F1 due to total internal reflection (and depending on the position of the absorber) to optimize the light distribution by scattering, particularly for operating state B2.

[0040] It is also conceivable that further operating states B3 , B4 , etc. may be provided, in which the switchable absorber is switched to a partially absorbing state, for example so that light can only be perceived conditionally from the side due to reduced brightness.

[0041] In particular, it is advantageous for special applications that in the two operating states B5 and B6, the mutually complementary parts of the switchable absorber are switched to absorb and transmit in a complementary manner. In an exemplary design, in the operating state B5, half of the absorber can be switched to absorb and the other half to transmit. Then, corresponding to the operating state B6, the circuit is reversed, that is, the aforementioned half of the absorber is switched to transmit, and the latter half is switched to absorb. In addition, each pixel should have at least two switchable absorbers, each belonging to one of the first half and the second half. Then, for example, when the operating states B5 and B6 are cycled, the light from the surface can be released alternately in one direction and then in another direction. In other words, the two switchable operating states B5 and B6 are cyclically set periodically to affect the light direction in a time sequence. This can be used, for example, to generate images in two different directions, for example, to image two different images displayed in a time sequence one after another and periodically in different directions according to the method of the present invention. If presented fast enough, i.e. higher than the flicker fusion frequency of the human eye, then depending on the orientation and image content on the surfaces F1, F2, ..., either automatic stereoscopic presentation (the observer's two eyes see two different images quasi-simultaneously) or two different images can provide images to two different observers simultaneously (so-called dual view).

[0042] In other words: In this design, a method for influencing the light propagation direction of a plurality of adjacent self-luminous and / or illuminated surfaces F1, F2, ... is used, wherein the surfaces F1, F2, ... comprise a transparent substrate on the light exit side, the transparent substrate being arranged above the luminous layer of the self-luminous or illuminated surfaces F1, F2, ..., and in a first alternative, each surface F1, F2, ... comprises its own substrate, and in a second alternative, all surfaces F1, F2, ... comprise a common planarly extending substrate, the method comprising the following steps:

[0043] For at least a plurality of surfaces F1, F2, ..., a switchable absorber is arranged on one or more partial surfaces of the corresponding substrate in the first alternative, or on one or more partial surfaces of a common substrate in the second alternative, on the light exit side, the spatial main propagation direction of the switchable absorber is arranged parallel to the light exit surface of the one or more substrates, ignoring a tolerance of up to 10°, and there are at least two individually switchable absorbers in front of each surface F1, F2, ..., which can be switched to transparent and opaque in a complementary manner to each other,

[0044] limiting the light propagation of the light emanating from each individual face F1, F2, ... so that the light from the face F1, F2, ... does not emerge through the substrate or through a portion of the substrate that is situated in front of another face in parallel projection, but rather emerges only through that portion of the substrate that is situated in front of the observed face in the case of parallel projection,

[0045] For operating state B5, the absorption effect of the option of turning on the switchable absorber and the transparency effect of the option complementary to the option of the switchable absorber are such that a portion of the light emitted from the surfaces F1, F2, ... is absorbed, while the remaining light is emitted unimpeded on the surface portion of the light exit side of the substrate on which the switchable absorber is not applied or is switched to a transparent absorber, whereby the light from the corresponding surfaces F1, F2, ... is visible only from a limited first viewing angle, which is particularly defined by the selection of the switchable absorber and the geometry of the switchable absorber, the geometry of the corresponding surfaces F1, F2, ..., the refractive index relationship in the structure and the thickness of the substrate,

[0046] For operating state B6, the transparent effect of the option of the switchable absorber is turned on and the absorption effect of the option complementary to the option of the switchable absorber is turned on, so that a part of the light emitted from the surfaces F1, F2, ... is absorbed, and the remaining light is emitted unimpeded on the surface portion of the light exit side of the substrate on which the switchable absorber is not applied or the absorber is switched to be transparent, so that the light from the corresponding surfaces F1, F2, ... is only visible from a limited second viewing angle, and the limited second viewing angle is particularly defined by the selection of the switchable absorber and the geometry of the switchable absorber, the geometry of the corresponding surfaces F1, F2, ..., the refractive index relationship in the structure and the thickness of the substrate,

[0047] The operating states B5 and B6 are connected successively in a cyclical manner, and at least two different image contents are displayed alternately on the surfaces F1, F2, ... in the same cyclical manner.

[0048] Thereby, an automatic stereoscopic display or a dual-view display is achieved according to the first and the limited second viewing angles and according to the image contents displayed on the surfaces F1 , F2 , . . . . . .

[0049] In principle, for a corresponding design, it is also possible to use more than two switchable absorbers on each surface F1, F2, ... to image more than two images in more than two directions in a time sequence. This allows so-called multi-viewing Figure 3 D system is possible, for example, in multi-view Figure 3 In a D system, a certain type of omnidirectional view can be achieved when the head moves.

[0050] The object of the present invention is also achieved by a structure for influencing the light propagation direction according to the present invention, the structure comprising:

[0051] a plurality of adjacent self-luminous and / or illuminated surfaces (F1, F2, ...), which on the light exit side comprise a transparent substrate, which is arranged above the luminescent layer of the self-luminous or illuminated surfaces (F1, F2, ...),

[0052] and in a first alternative, each surface (F1, F2, . . . ) comprises its own base plate, and in a second alternative, all surfaces (F1, F2, . . . ) comprise a common, planarly extending base plate,

[0053] a switchable absorber, for at least a plurality of faces (F1, F2, . . . ), the switchable absorber being arranged on the light exit side in a first alternative on one or more partial faces of the respective substrate or in a second alternative on one or more partial faces of a common substrate, wherein the spatial main propagation direction of the switchable absorber is arranged parallel to the light exit face of the substrate or substrates, ignoring a tolerance of a maximum of 10°,

[0054] means for limiting the light propagation of the light emanating from each individual facet (F1, F2, ...) so that the light coming from a facet (F1, F2, ...) does not emerge through the substrate or through a portion of the substrate which is situated in front of another facet in parallel projection, but only through a portion of the substrate which is situated in front of the observed facet in parallel projection,

[0055] Means for switching the absorption effect of the switchable absorber on and off, such that:

[0056] For a first operating state B1, the absorption effect of the switchable absorber is switched on, whereby a portion of the light emitted from the surface (F1, F2, ...) is absorbed, while the remaining light is emitted unhindered at a surface portion of the light exit side of the substrate on which the switchable absorber is not applied, whereby the light from the corresponding surface (F1, F2, ...) is only visible from a restricted viewing angle, which is defined in particular by the geometry of the switchable absorber, the geometry of the corresponding surface (F1, F2, ...), the refractive index relationship in the structure and the thickness of the substrate, and

[0057] For the second operating state B2, the absorption effect of the switchable absorber is turned off, so that the light emitted from the surface (F1, F2, ...) can propagate through the absorber unimpeded without taking into account the residual absorption loss of the switchable absorber, so that the light from the corresponding surface (F1, F2, ...) is visible from an unrestricted viewing angle.

[0058] Here, the other design variations and mechanism interactions given above are also applicable and will not be described in detail here for redundancy reasons.

[0059] In principle, if the above parameters are varied within certain limits, the performance of the invention remains unchanged.

[0060] It goes without saying that the features mentioned above and the features still to be explained below can be used not only in the combination specified but also in other combinations or alone, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The invention is explained in more detail below with reference to the accompanying drawings, which also illustrate features essential to the invention.

[0062] in:

[0063] Figure 1 A schematic diagram for explaining the method according to the invention in operating state B1 is shown.

[0064] Figure 2 A schematic diagram for explaining the method according to the invention in operating state B2 is shown.

[0065] Figure 3 A schematic diagram is shown for explaining the limitation of an obliquely directed light beam according to a first embodiment,

[0066] Figure 4 A schematic diagram for explaining the limitation of an obliquely directed light beam according to a second design is shown,

[0067] Figure 5 A schematic diagram is shown for explaining an extended embodiment of the method according to the invention in operating state B1.

[0068] Figure 6 A schematic diagram is shown for explaining an extended embodiment of the method according to the invention in operating state B2.

[0069] Figure 7a to Figure 7h A schematic diagram showing a possible design variant of a switchable absorber in a top view,

[0070] Figure 8 Schematic diagram showing a design in which each switchable absorber has a pinhole geometry and the geometric center of gravity is shifted from one face to another,

[0071] Figure 9a and Figure 9b A schematic diagram showing a design using a reverse pinhole and utilizing internal total reflection of the light beam is shown.

[0072] Fig.10a and Fig.10b Schematic diagram showing a design approach for using a permanent scattering microstructure on a switchable absorber, and

[0073] Fig.11a and Fig.11b The schematic diagram shows a configuration with operating states B5 and B6 , in which different images can each be displayed in different directions.

[0074] The drawings are not true to scale and merely reflect a schematic representation. DETAILED DESCRIPTION

[0075] exist Figure 1 A schematic diagram for explaining the method according to the present invention in operating state B1 is shown in FIG. Figure 2 Operating state B2 is shown.

[0076] In the method according to the invention discussed for influencing the light propagation direction of a plurality of adjacent self-luminous and / or illuminated surfaces (F1, F2, ...), each surface has a transparent substrate 1 on the light exit side, in a first alternative, each surface has its own substrate 1, or in a second alternative, all surfaces (F1, F2, ...) use a common substrate 1. Here, the substrate 1 is arranged above, but not necessarily directly above, the luminescent layer of the self-luminous or illuminated surface (F1, F2, ...), such as Figure 1 shown.

[0077] The method according to the invention now comprises the following steps:

[0078] For at least a plurality of faces (F1, F2, . . . ), a switchable absorber 2 is arranged on the light exit side in a first alternative on one or more (real or real subset) facets of the corresponding substrate 1 or in a second alternative on one or more facets of a common substrate 1, wherein the spatial main propagation direction of the switchable absorbers 2 is arranged parallel to the light exit face of the substrate 1 or substrates 1, ignoring a tolerance of a maximum of 10°,

[0079] The light propagation of the light emitted from each individual face (F1, F2, ...) is limited so that the light from the face (F1, F2, ...) does not exit through the substrate 1 or through a portion of the substrate 1 that is located in front of another face in the case of parallel projection, but only through a portion of the substrate 1 that is located in front of the observed face in the case of parallel projection (this will be referred to below). Figure 3 and Figure 4 for a more detailed explanation),

[0080] like Figure 1 As shown, in the first operating state B1, the absorption effect of the switchable absorber 2 is turned on, so that a part of the light emitted from the surface (F1, F2, ...) is absorbed, while the remaining light is emitted unimpeded on the surface portion of the light exit side of the substrate 1 on which the switchable absorber 2 is applied, so that the light from the associated surface (F1, F2, ...) is only visible from a restricted viewing angle, which is particularly defined by the geometry of the switchable absorber 2, the geometry of the corresponding surface (F1, F2, ...), the refractive index relationship in the structure and the thickness of the substrate 1,

[0081] like Figure 2 As shown, in the second operating state B2, the absorption effect of the switchable absorber 2 is turned off, so that the light emitted from the surface (F1, F2, ...) propagates through the absorber without hindrance from the surface, ignoring the residual absorption loss of the switchable absorber 2, so that the light from the associated surface (F1, F2, ...) can be seen from an unrestricted viewing angle (at least from a viewing angle larger than that in the operating state B1).

[0082] In the first variant of the invention, as well as in all subsequent variants, a restricted viewing angle does not necessarily mean that no light is emitted at all in certain directions. Rather, a certain residual light may still be emitted there, but this may impede viewing comfort. Even in areas provided for restricted viewing, typical values ​​for such residual light (measured in brightness) are only a few percent of the peak value (perceivable from the dedicated viewing area of ​​the restricted viewing angle).

[0083] In a first alternative, each face (F1, F2, ...) has its own substrate 1 (or 1.1, 1.2, 1.3, etc.). These substrates are then preferably arranged essentially in one plane. In contrast, in a second alternative, all faces (F1, F2, ...) can also include a common, planarly extending substrate 1.

[0084] In particular, the switchable absorbers 2 corresponding to all surfaces (F1, F2, . . . ) can be switched simultaneously when the entire surface is switched between operating states B1 and B2, or only part of the surface is switched between operating states B1 and B2, in such a way that only a proper subset of the switchable absorbers 2 is switched.

[0085] The limitation of the light propagation of the light emitted from each individual face (F1, F2, ...) is achieved, for example, by arranging the permanent absorption layer 3 between the individual substrates 1 in a first alternative or in a common substrate 1 in a second alternative. Figure 3 reflected in Figure 3 In the first embodiment, the principle diagram of limiting an obliquely directed light beam is shown. The absorption layer 3 can consist of opaque particles in, for example, an adhesive, silicone or a polymer. Alternatively, the absorption layer can also be present as an opaque solid material, such as a metal or one or more vapor-deposited layers. Figure 3 In this case, a light beam emitted from face F1 in the direction of substrate portion 1 located in front of face F2 is absorbed by absorption layer 3. Conversely, the same applies to a light beam from face F2 emitted in the direction of substrate portion 1 located in front of face F1.

[0086] In a special embodiment, the absorbent layer 3 can also be switched between a transparent and an absorbent state. The planes in which the switchable absorber 2 and the (permanent or optionally switchable) layer 3 are respectively arranged are preferably arranged perpendicular to each other, ignoring a tolerance of a maximum of 25 degrees.

[0087] In contrast, Figure 4 The schematic diagram of the limitation of the obliquely directed light beam is shown in a second design. In this case, the limitation of the light propagation of the light emitted from each individual face (F1, F2, ...) is carried out by selecting the refractive index relationship of the substrate 1 relative to air in such a way that the unwanted light beam is converted into a total reflection (at Figure 4 In practice, permanent absorbers (not shown in the figure) are usually installed on the narrow sides of the substrate to absorb the light from the total reflection angle.

[0088] Other variations of the described limitation of the obliquely oriented light beam can be envisaged.

[0089] In a further development of the invention, a collimating lens 4 is arranged on the facets of the substrate 1 or substrates 1 on which the switchable absorber 2 is not applied, in order to achieve further beam focusing and to be able to better limit the viewing angle. Figure 5 A schematic diagram illustrating this variant is shown in operating state B1, and Figure 6 The schematic diagram is shown in operating state B2.

[0090] Each switchable absorber 2 can comprise, for example, an electrochromic layer and / or a liquid crystal layer and / or a layer based on electrophoresis and / or a layer based on electrowetting with absorbent particles, which can all be controlled by an electric field. In this way, the absorption effect can be easily switched on and off. Of course, there are mechanisms for control for this.

[0091] In the case of electrochromic layers used as absorber 2 , these can be cost-effectively vapour-deposited onto one or more substrates 1 and contacted with electrodes for control.

[0092] In a further embodiment, each switchable absorber 2 can include a switchable filter which absorbs the color spectrum of the colors emitted by the surface (F1, F2, ...) below it in a first state and transmits it in a second state, wherein the switchable filter can be manipulated by an electric field. For example, this can be a quantum dot.

[0093] Each switchable absorber 2 preferably has the geometry of a pinhole. In this case, it is obviously possible to provide more than one (permanently) non-absorbing geometrical portion for each switchable absorber 2 or each pinhole.

[0094] Here, Figure 7a to Figure 7h Various schematic diagrams of possible design variants of the switchable absorber 2 are shown in plan view. Figure 7a to Figure 7h Arranging the absorber in front of each face (F1, F2, ...) accordingly has the following effect on the light propagation direction in operating state B1 compared to operating state B2 (assuming that the observer will observe the substrate 1 approximately from the perpendicular bisector of the substrate):

[0095] Figure 7a : The direction of light propagation to the left and right and up and down is restricted,

[0096] Figure 7b : The light propagation directions are restricted to the left and right respectively,

[0097] Figure 7c : The light propagation directions towards the left and right are restricted respectively, where the restriction towards the right is stronger than the restriction towards the left,

[0098] Figure 7d: The light propagation direction to the left and right and up and down is limited, but it has a conical propagation angle with a circular cross section,

[0099] Figure 7e : The light propagation direction in all directions above the substrate 1 is limited, but has a conical propagation angle with a hexagonal cross section,

[0100] Figure 7f : The light propagation direction in all directions above the substrate 1 is limited, but has a conical propagation angle with a circular cross section,

[0101] Figure 7g : The light propagation direction above the substrate 1 in all directions is limited, but has a conical propagation angle with two circular cross sections, and

[0102] Figure 7h : The light propagation directions toward the left and right and up and down are restricted so that the light reaches only outside the conical blocking angle with a circular cross-section (the so-called reverse pinhole shape).

[0103] In the mentioned Figure 7a to Figure 7h In the figure, the marking with the substrate 1 is drawn in the area where no absorber part 2 is applied. This should be particularly illustrated: the absorber 2 does not cover the entire surface of one or more substrates 1.

[0104] Different switchable absorbers 2 can also have different geometries, for example according to Figure 7a to Figure 7h However, all absorbers 2 generally have substantially the same geometric shape. When the same shape is applied to all absorbers 2, these absorbers can still be slightly stretched or compressed towards the edges by the correction factor.

[0105] Furthermore, the absorbent body 2 may have a reverse pinhole geometry, such as Figure 7h As shown (with Figure 7d In the case of such reverse pinholes, in contrast to non-reverse pinholes, those facets or areas of the substrate which are otherwise not covered are covered with a switchable absorber, or the already covered facets or areas of the substrate are not covered with a switchable absorber. Such reverse pinholes are used in a special design of the invention (see Figure 9a and Figure 9b ).

[0106] In absolute numbers, depending on the design of the surfaces (F1, F2, ...), the surface of the absorber 2 can be from a few dozen square micrometers to a few square millimeters, or even larger. Other designs are conceivable and can be implemented depending on the application.

[0107] according to Figure 7gA variation can also be configured so that the left absorber portion (i.e., the portion on the left side of the dotted line) of each absorber 2 is switched to an absorbing function for operating state B5, and the other right half is switched to a transmitting function. Then, for operating state B6, the circuit is reversed, i.e., the mentioned first half is switched to a transmitting function, and the mentioned second half of the absorber 2 is switched to an absorbing function. Therefore, for example, under the setting of the periodic cycle of operating states B5 and B6, the light from the surface can be released alternately in one direction and then in another direction. In other words, operating states B5 and B6 are cyclically set to affect the direction of light in a time sequence. This can be used, for example, to generate images in two different directions, for example, to image two different images displayed in a time sequence successively and periodically in different directions according to the method of the present invention. If this takes place quickly enough, i.e. above the flicker fusion frequency of the human eye, then, depending on the directionality and image content on the surfaces F1, F2, ..., either automatic stereoscopic presentation (the observer's two eyes see two different images quasi-simultaneously) or two different images provide images to two different observers simultaneously (so-called dual view) is possible.

[0108] to this end, Fig.11a and Fig.11b A schematic diagram of a design scheme with operating states B5 and B6 is shown, in which correspondingly different images can be displayed in different directions. In other words, in this design scheme, a method for influencing the light propagation direction of a plurality of adjacent self-luminous and / or illuminated surfaces F1, F2, ... is used, wherein the surfaces F1, F2, ... comprise a transparent substrate 1 on the light exit side, the substrate 1 being arranged above the luminous layer of the self-luminous or illuminated surfaces F1, F2, ..., and in a first alternative, each surface F1, F2, ... comprises its own substrate 1, and in a second alternative, all surfaces F1, F2, ... comprise a common planarly extending substrate 1, comprising the following steps:

[0109] For at least a plurality of surfaces F1, F2, ..., a switchable absorber 2 is arranged on one or more partial surfaces of the corresponding substrate 1 in a first alternative or on one or more partial surfaces of a common substrate 1 in a second alternative on the light exit side, wherein the spatial main propagation direction of these switchable absorbers 2 is arranged parallel to the light exit surface of one substrate 1 or multiple substrates 1 without taking into account a tolerance of up to 10°, and before each surface F1, F2, ..., there are at least two individually switchable absorbers 2, which can be switched to transparent and opaque respectively in a complementary manner to each other,

[0110] limiting the light propagation of the light emanating from each individual face F1, F2, ... so that the light from the face F1, F2, ... does not emerge through the substrate 1 or through a portion of the substrate 1 situated in front of another face in the case of parallel projection, but rather emerges only through a portion of the substrate 1 situated only in front of the observed face in the case of parallel projection,

[0111] For operating state B5, the absorption effect of the option of turning on the switchable absorber 2 and the transparency effect of the option complementary to the option of the switchable absorber 2 are turned on, so that a part of the light emitted from the surfaces F1, F2,... is absorbed, while the remaining light is emitted unimpeded on the surface portion of the light exit side of the substrate 1 on which the switchable absorber 2 is not applied or the absorber 2 is switched to be transparent, so that the light from the corresponding surfaces F1, F2,... is visible only from a limited first viewing angle, and the limited first viewing angle is particularly limited by the selection of the switchable absorber 2 and the geometry of the switchable absorber, the geometry of the corresponding surfaces F1, F2,..., the refractive index relationship in the structure and the thickness of the substrate 1,

[0112] For operating state B6, the transparent effect of the option of the switchable absorber 2 is turned on and the absorption effect of the option complementary to the option of the switchable absorber 2 is turned on, so that a part of the light emitted from the surfaces F1, F2,... is absorbed, and the remaining light is emitted unimpeded on the surface portion of the light exit side of the substrate 1 on which the switchable absorber 2 is not applied or the absorber 2 is switched to be transparent, so that the light from the corresponding surfaces F1, F2,... is only visible from a limited second viewing angle, and the limited second viewing angle is particularly limited by the selection of the switchable absorber 2 and the geometry of the switchable absorber, the geometry of the corresponding surfaces F1, F2,..., the refractive index relationship in the structure and the thickness of the substrate 1,

[0113] The operating states B5 and B6 are connected successively in a cyclical manner, and at least two different image contents are displayed alternately on the surfaces F1, F2, ... in the same cyclical manner.

[0114] Thereby, an automatic stereoscopic display or a dual-view display is achieved according to the first and the limited second viewing angles and according to the image contents displayed on the surfaces F1 , F2 , . . . . . .

[0115] also, Fig.11aOperating state B5 is shown: here, due to the option of switching to an opaque switchable absorber 2-a here, only the light beam is allowed to pass through the right side (i.e., by the complementary option of switching to a transparent switchable absorber 2-b). In addition, the aforementioned limitation of the light propagation of the light emitted from each individual face (F1, F2, ...) also occurs here, for example, by arranging the permanent absorption layer 3 between the faces of two individual substrates 1 in the first alternative or in a common substrate 1 in the second alternative.

[0116] on the contrary, Fig.11b The next segment in the cycle is shown in operating state B6: here, due to the option of switching the switchable absorber 2 - b here to be opaque, only the light beam is allowed to pass to the left (ie, by the complementary option of switching the switchable absorber 2 - a to be transparent).

[0117] The method according to the invention is of particular practical significance when there are multiple self-luminous surfaces (F1, F2, ...), each of which corresponds to the smallest pixel of an OLED screen, a mini-LED screen, a VCSEL screen, a QLED screen, an LED screen or a micro-LED screen, so that such a screen can be switched between an operating state B1 for a limited viewing angle and an operating state B2 for an unlimited viewing angle. Depending on the design of the imaging technology, RGB sub-pixels (red, green, blue), other monochrome or full-color pixels can all be regarded as smallest pixels. The screen technology can generally be self-luminous or illuminated, such as LCD, SED, FED or other types.

[0118] exist Figure 8 In another embodiment shown, each switchable absorber 2 has the geometry of a pinhole. Here, depending on the application, the pinholes can be advantageously arranged on the common substrate 1 or one or more facets of the corresponding substrate 1, so that the geometrical center of gravity of the self-luminous or illuminated face F1, F2, ... does not coincide with the geometrical center of gravity of those facets that are not covered by the switchable absorber 2 when at least the facets F1, F2, ... are in parallel projection. This can be seen from Figure 8 As can be seen in . This achieves that the restricted light propagation direction of the individual faces F1, F2, ... is varied and it is particularly advantageous that when the faces F1, F2, ... are viewed by the observer 7, when the faces F1, F2, ... are on the left, the light is radiated or emitted to the right (ie, towards the observer 7) and when the faces F1, F2, ... are on the right, the light is radiated or emitted to the left (ie, again towards the observer). In this way, an improved uniformity can be achieved despite the restricted light beam direction.

[0119] exist Figure 8In FIG. 1 , this optimization of the light direction of the faces F1, F2, F3 towards the observer 7 can be seen. Since this is only a schematic diagram, only three faces F1, F2, F3 are drawn, which are intended to represent the left, middle and right faces in the corresponding implementation. However, in reality, there are multiple such self-luminous or illuminated faces F1, F2, F3, ... It is obvious to a person skilled in the art that the movement of the geometric center of gravity of the above-mentioned self-luminous or illuminated faces F1, F2, ... on all these faces then occurs gradually.

[0120] In addition, faces F1, F2, and F3 are Figure 8 The faces may actually be spaced apart, but they do not have to be.

[0121] In another design, Figure 9a and Figure 9b As shown in the schematic diagram in FIG. , each switchable absorber 2 has a reverse pinhole geometry (e.g., Figure 7h In the case of such a reverse pinhole, in contrast to a non-reverse pinhole, those facets or areas of the substrate which are otherwise uncovered are covered with a switchable absorber 2, or the already covered facets or areas of the substrate are not covered with a switchable absorber.

[0122] Therefore, according to Figure 9a The operating state B1 for the restricted mode is shown in a design of , in which the switchable absorber is arranged substantially opposite the self-luminous or illuminated surface F1. The light emitted from the surface F1 is now absorbed by the switchable absorber 2. However, the light beam that is totally reflected further inwards within the substrate 1 is spatially close to the absorber 2 within the substrate 1.

[0123] Another special feature of this design is that the microstructured decoupling element 5 is arranged on the facet not covered by the absorber 2, and the decoupling element decouples the internal total reflection light beam from the common substrate 1 or the corresponding substrate 1 by changing the direction, and the light decoupled by the microstructured decoupling element 5 is only visible from a limited viewing angle. Figure 9a The beam is shown as being decoupled upwards.

[0124] On the contrary, Figure 9b As shown, if the configuration is switched in operating state B2 , ie the absorber 2 becomes transparent, light not only reaches the observer due to the decoupling element 5 , but also directly reaches the surface F1 , which now passes through the absorber 2 without taking into account technically determined losses.

[0125] In this respect, this embodiment has a partially different effect than all the embodiments described above, since here the distribution of the absorbers 2 in the form of inverted pinholes and the use of internally totally reflected light beams come into play.

[0126] at last, Fig.10a and Fig.10b A further embodiment is shown in which a permanently scattering microstructure 6 is arranged on a switchable absorber 2. Fig.10a and Fig.10b The schematic diagram can be seen as based on Figure 5 and Figure 6 The embodiments of the invention are correspondingly improved, but the use of a permanently scattering microstructure 6 on a switchable absorber represents a reliable mechanism for all of the embodiments described, in order to optimize the light distribution in particular for the B2 operating state. Fig.10a , the scattering microstructure 6 has no effect in the operating state B1, because the absorber 2 is switched there to an absorbing effect, and therefore the light from the surface F1 does not actually reach the scattering microstructure 6. On the contrary, Fig.10b It is shown that in operating state B2 (in which the switchable absorber 2 is switched to transparent), the scattering microstructure 6 scatters light that may reach the absorber 2 directly from surface F1 due to total internal reflection (and depending on the position not shown here) to optimize the light distribution by scattering, particularly for operating state B2.

[0127] The structure for influencing the light propagation direction according to the present invention can also be referred to as Figure 1 and Figure 2 To explain. The structure includes:

[0128] A plurality of adjacent self-luminous and / or illuminated surfaces (F1, F2, ...), each of which comprises, on the light exit side, a (one each) transparent substrate 1, which is arranged above the luminous layer of the self-luminous or illuminated surfaces (F1, F2, ...), and in a first alternative, each surface (F1, F2, ...) comprises its own substrate (1), and in a second alternative, all surfaces (F1, F2, ...) comprise a common, planarly extending substrate (1),

[0129] switchable absorbers 2, for at least a plurality of faces (F1, F2, ...), which are arranged on the light exit side in a first alternative on one or more partial faces of the corresponding substrate 1 or in a second alternative on one or more partial faces of a common substrate (1), wherein the spatial main propagation direction of the switchable absorbers 2 is arranged parallel to the light exit face of the substrate or substrates 1, ignoring a tolerance of a maximum of 10°,

[0130] Means for limiting the light propagation of the light emitted from each individual face (F1, F2, ...) so that the light from a face (F1, F2, ...) does not emerge through the substrate 1 or the portion of the substrate 1 that is located in front of another face in parallel projection, but only through the portion of the substrate 1 that is located in front of the observed face in parallel projection, wherein this solution is Figure 3 and Figure 4 As an example,

[0131] A mechanism (not shown in the figure) for switching the absorption effect of the switchable absorber 2 on and off, so that:

[0132] For the first operating state B1, the absorption effect of the switchable absorber 2 is switched on, e.g. Figure 1 As shown, a portion of the light emitted from the surfaces (F1, F2, ...) is absorbed, while the remaining light is emitted unimpeded on the surface portion of the light exit side of the substrate 1 on which the switchable absorber 2 is not applied, whereby the light from the corresponding surface (F1, F2, ...) is visible only from a restricted viewing angle, which is particularly defined by the geometry of the switchable absorber 2, the geometry of the corresponding surface (F1, F2, ...), the refractive index relationship in the structure and the thickness of the substrate 1, and

[0133] For the second operating state B2, the absorption effect of the switchable absorber 2 is turned off, such as Figure 2 As shown, light emitted from the faces (F1, F2, ...) propagates unhindered through the switchable absorber 2, ignoring residual absorption losses, so that light from the corresponding faces (F1, F2, ...) is visible from an unrestricted viewing angle.

[0134] In addition, the design variations and mechanism interactions given above are also applicable and will not be described in detail here for redundancy reasons.

[0135] The above-described method according to the invention for influencing the direction of light propagation and the structure according to the invention achieve the following objectives: both the method and the structure are low-cost and suitable for large-scale production and can be generally used, in particular for use with OLED screens, but also with other types of screen types, in order to switch between a viewing protection mode and a free viewing mode, wherein the resolution of such a screen is substantially not reduced.

[0136] The invention described above can be used advantageously in combination with an image display device in various situations for displaying and / or entering confidential data, for example when entering a PIN or for displaying data at a cash machine or payment terminal or for entering passwords or reading e-mails on a mobile device. The invention can also be used in passenger cars in order to present selectable content to the driver in a visual manner or, alternatively, to shield him from disruptive image content. Other applications are in the field of lighting and advertising, in particular for avoiding light smog.

Claims

1. A method for influencing the light propagation direction of a plurality of adjacent self-luminous and / or illuminated surfaces (F1, F2, ...), the plurality of adjacent self-luminous and / or illuminated surfaces comprising a transparent substrate (1) on the light exit side, wherein: The substrate (1) is arranged above the luminous layer of the self-luminous or illuminated surface (F1, F2, ...), and in a first alternative, each surface (F1, F2, ...) comprises its own substrate (1), and in a second alternative, all surfaces (F1, F2, ...) comprise a common, planarly extending substrate (1), the method comprising the following steps: For at least a plurality of surfaces (F1, F2, ...), a switchable absorber (2) is arranged on the light exit side in a first alternative on one or more partial surfaces of the corresponding substrate (1) or in a second alternative on one or more partial surfaces of a common substrate (1), wherein the spatial main propagation direction of the switchable absorber (2) is arranged parallel to the light exit surface of the substrate or substrates (1) without taking into account a tolerance of a maximum of 10°, limiting the light propagation of the light emitted from each individual face (F1, F2, ...) so that the light from the face (F1, F2, ...) does not emerge through the substrate (1) or through a portion of the substrate (1) that is located in front of another face in parallel projection, but only through a portion of the substrate that is located in front of the observed face in parallel projection, For a first operating state B1, the absorption effect of the switchable absorber (2) is switched on, so that a portion of the light emitted from the surfaces (F1, F2, ...) is absorbed, while the remaining light is emitted unhindered at the surface portion of the light exit side of the substrate (1) on which the switchable absorber (2) is not applied, whereby the light from the corresponding surface (F1, F2, ...) is visible only from a restricted viewing angle, For the second operating state B2, the absorption effect of the switchable absorber (2) is turned off so that the light emitted from the surfaces (F1, F2, ...) can propagate through the absorber unimpeded, ignoring the residual absorption losses of the switchable absorber (2), so that the light from the corresponding surfaces (F1, F2, ...) can be visible from an unrestricted viewing angle.

2. The method according to claim 1, wherein the restricted viewing angle is defined by the geometry of the switchable absorber (2), the geometry of the corresponding faces (F1, F2, ...), the refractive index relationships in the structure and the thickness of the substrate (1).

3. The method according to claim 1 or 2, characterized in that: The absorbers (2) corresponding to all surfaces (F1, F2, . . .) are switched simultaneously when the entire surface is switched between operating states B1 and B2, or only part of the surface is switched between operating states B1 and B2, in such a way that only a proper subset of the absorbers (2) that can be switched is switched.

4. The method according to claim 1 or 2, characterized in that: The limitation of the light propagation of the light emitted from each individual face (F1, F2, . . .) is achieved by arranging a permanent or switchable absorption layer (3) between the individual substrates (1) in a first alternative or in a common substrate (1) in a second alternative.

5. The method according to claim 4, wherein the planes in which the switchable absorber (2) and the absorber layer (3) are respectively arranged are arranged perpendicular to one another, ignoring a tolerance of a maximum of 25 degrees.

6. The method according to claim 1 or 2, characterized in that: The limitation of the optical propagation of the light emitted from each individual face (F1, F2, . . .) is carried out by choosing the refractive index relationship of the substrate (1) relative to air in such a way that unwanted light beams are converted into total reflection.

7. The method according to claim 1 or 2, characterized in that: On the partial surfaces of a substrate or a plurality of substrates (1) on which the switchable absorber (2) is not applied, collimating lenses (4) are respectively arranged to further achieve beam focusing.

8. The method according to claim 1 or 2, characterized in that: Each switchable absorber (2) comprises an electrochromic layer and / or a liquid crystal layer and / or a layer based on electrophoresis and / or a layer based on electrowetting with absorbent particles, each of which can be manipulated by an electric field.

9. The method according to claim 1 or 2, characterized in that: Each switchable absorber (2) comprises a switchable filter which absorbs a color spectrum of colors emitted by a surface (F1, F2, . . . ) below it in a first state and transmits the color spectrum in a second state, wherein the switchable filter can be controlled by an electric field in dependence on its state.

10. The method according to claim 1 or 2, characterized in that: Each switchable absorber (2) has a pinhole or reverse pinhole geometry.

11. The method according to claim 1 or 2, characterized in that: There are a plurality of self-luminous or illuminated surfaces (F1, F2, . . . ) which together form a screen, so that such a screen can be switched between an operating state B1 for a restricted viewing angle and an operating state B2 for an unlimited viewing angle.

12. The method according to claim 11, characterized in that The self-luminous surfaces (F1, F2, ...) correspond to the smallest pixel or smallest pixel cluster of the OLED screen, mini-LED screen, VCSEL screen, QLED screen, LED screen or micro-LED screen, respectively.

13. The method according to claim 11, wherein: Each switchable absorber (2) has the geometry of a pinhole, characterized in that the pinhole is arranged on a common substrate (1) or one or more partial surfaces of the corresponding substrate (1) so that the geometric center of gravity of the self-luminous or illuminated surface (F1, F2, ...) and the geometric center of gravity of the surface portion not covered by the switchable absorber (2) do not coincide with each other in parallel projection, at least for a part of the surface (F1, F2, ...).

14. The method according to claim 1 or 2, wherein: Each switchable absorber (2) has a reverse pinhole geometry, characterized in that a microstructured decoupling element (5) is arranged on a facet not covered by the absorber (2), wherein the microstructured decoupling element decouples the internally totally reflected light beam from the common substrate (1) or the corresponding substrate (1) by changing its direction, and the light decoupled by the microstructured decoupling element (5) is visible only from a restricted viewing angle.

15. The method according to claim 1 or 2, characterized in that: A permanently scattering microstructure (6) is arranged on the switchable absorber (2).

16. The method according to claim 15, characterized in that The scattering microstructure (6) in the substrate (1) decouples and / or scatters the internally totally reflected light beam.

17. The method according to claim 11, characterized in that The illuminated surfaces (F1, F2, . . . ) correspond to the smallest pixel or the smallest pixel cluster of the LCD screen.

18. Use of the method according to any of the preceding claims on a planar light source, wherein the planar light source consists of a self-luminous or illuminated surface (F1, F2, ...), for backlighting of an LCD panel, whereby the LCD panel operates in a first operating state B1 corresponding to a restricted viewing angle and in a second operating state B2 corresponding to an unrestricted viewing angle.

19. A structure for influencing the direction of light propagation, comprising: A plurality of adjacent self-luminous and / or illuminated surfaces (F1, F2, ...), which on the light exit side comprise a transparent substrate (1), said substrate (1) being arranged above the luminous layer of the self-luminous or illuminated surfaces (F1, F2, ...), and in a first alternative, each surface (F1, F2, ...) comprises its own substrate (1), and in a second alternative, all surfaces (F1, F2, ...) comprise a common, planarly extending substrate (1), A switchable absorber (2), for at least a plurality of faces (F1, F2, ...), which is arranged on the light exit side in a first alternative on one or more partial faces of the corresponding substrate (1) or in a second alternative on one or more partial faces of a common substrate (1), wherein the spatial main propagation direction of the switchable absorber (2) is arranged parallel to the light exit face of the substrate or substrates (1) without taking into account a tolerance of a maximum of 10°, means for limiting the light propagation of the light emitted from each individual face (F1, F2, ...) so that the light from the face (F1, F2, ...) does not emerge through the substrate (1) or through a portion of the substrate (1) which is situated in front of another face in parallel projection, but only through a portion of the substrate which is situated in front of the observed face in parallel projection, A mechanism for switching the absorption effect of a switchable absorber (2) on and off, so that: In a first operating state B1, the absorption effect of the switchable absorber (2) is switched on, whereby a portion of the light emitted from the surfaces (F1, F2, ...) is absorbed, while the remaining light is emitted unhindered from a surface portion of the light exit side of the substrate (1) on which the switchable absorber (2) is not applied, whereby the light from the corresponding surface (F1, F2, ...) is visible only from a restricted viewing angle, and For the second operating state B2, the absorption effect of the switchable absorber (2) is turned off, whereby the light emitted from the surfaces (F1, F2, ...) can propagate through the absorber unimpeded, ignoring the residual absorption losses of the switchable absorber (2), whereby the light from the corresponding surfaces (F1, F2, ...) is visible from an unrestricted viewing angle.

20. The structure of claim 19, wherein the restricted viewing angle is defined by the geometry of the switchable absorber (2), the geometry of the corresponding faces (F1, F2, ...), the refractive index relationships in the structure and the thickness of the substrate (1).

21. A method for influencing the light propagation direction of a plurality of adjacent self-luminous and / or illuminated surfaces (F1, F2, ...), the plurality of adjacent self-luminous and / or illuminated surfaces comprising a transparent substrate (1) on the light exit side, the substrate (1) being arranged above the luminous layer of the self-luminous or illuminated surfaces (F1, F2, ...), and in a first alternative, each surface (F1, F2, ...) comprises its own substrate (1), and in a second alternative, all surfaces (F1, F2, ...) comprise a common, planarly extending substrate (1), the method comprising the following steps: For at least a plurality of surfaces (F1, F2, ...), a switchable absorber (2) is arranged on one or more partial surfaces of the corresponding substrate (1) in a first alternative, or on one or more partial surfaces of a common substrate (1) in a second alternative, on the light exit side, the spatial main propagation direction of the switchable absorber (2) being arranged parallel to the light exit surface of the substrate or substrates (1) without taking into account a tolerance of a maximum of 10°, and at least two individually switchable absorbers (2) are arranged in front of each surface (F1, F2, ...), the absorbers being switchable to transparent and opaque in a complementary manner to each other, limiting the light propagation of the light emitted from each individual facet (F1, F2, ...) so that the light from the facet (F1, F2, ...) does not emerge through the substrate (1) or through a portion of the substrate (1) that is located in front of another facet in parallel projection, but rather emerges only through a portion of the substrate that is located in front of the observed facet in parallel projection, For operating state B5, an optional absorption effect of the switchable absorber (2) is turned on, and an optional transparency effect of the switchable absorber (2) that is complementary to the optional switchable absorber (2) is turned on, so that a portion of the light emitted from the surface (F1, F2, ...) is absorbed, while the remaining light is emitted unimpeded on the surface portion of the light exit side of the substrate (1) on which the switchable absorber (2) is not applied or the absorber (2) is switched to be transparent, so that the light from the corresponding surface (F1, F2, ...) is only visible from a limited first viewing angle, For operating state B6, the transparent effect of the option of the switchable absorber (2) is turned on, and the absorption effect of the option of the switchable absorber (2) complementary to the option of the switchable absorber (2) is turned on, so that a part of the light emitted from the surface (F1, F2, ...) is absorbed, and the remaining light is emitted unimpeded on the surface portion of the light exit side of the substrate (1) on which the switchable absorber (2) is not applied or the absorber (2) is switched to be transparent, so that the light from the corresponding surface (F1, F2, ...) is only visible from a restricted second viewing angle, In this case, operating states B5 and B6 are successively switched on in a cyclical manner, and at least two different image contents are alternately displayed on the surfaces (F1, F2, . . . ) in the same cyclical manner. Thereby, an automatic stereoscopic display or a dual-view display is achieved according to the restricted first viewing angle and the restricted second viewing angle and according to the image content displayed on the plane (F1, F2, . . .).

22. A method according to claim 21, wherein the restricted first viewing angle is defined by the choice of the switchable absorber (2) and the geometry of the switchable absorber, the geometry of the corresponding faces (F1, F2, ...), the refractive index relationship in the structure and the thickness of the substrate (1).

23. A method according to claim 21 or 22, wherein the restricted second viewing angle is defined by the selection of the switchable absorber (2) and the geometry of the switchable absorber, the geometry of the corresponding faces (F1, F2, ...), the refractive index relationship in the structure and the thickness of the substrate (1).

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