Screen with switchable light filter

Abstract

The invention relates to a screen comprising an image generator (2) which has a first raster (Ra) comprising pixels (PBild); a switchable light filter (5) with a first optical element (1) which comprises a plurality of light-absorbing transition dipole moments (DP1, DP2), wherein the plurality (DP1) of transition dipole moments are oriented parallel to a first preferred direction, which can be selected for the first optical element (1), with a tolerance or vary about same such that light which is incident on the first optical element (1) is transmitted or at least partly absorbed on the basis of the polarization state and the direction of incidence thereof; means (4, in particular ITO1, ITO2) for selectively generating at least one first electric field (EF1) or a second electric field (EF2), said means being grouped in order form a second raster (Rb) comprising pixels (PLC); and a liquid crystal layer (3) which is acted upon by the respective electric field generated at each pixel (PLC) and which influences the polarization state of light passing through the liquid crystal layer on the basis of the electric field. The first and second raster (Ra, Rb) differ in at least one of the parameters of resolution, pixel shape, pixel size, raster shape, base angle of the coordinate axes (R1, R2) of the two rasters, orientation of the coordinate axes (R1, R2), and / or the number of respective pixels (PLC) or (PBild), whereby visually visible superimpositions of the image generator (2) and other components of the screen are reduced. The invention also relates to an embodiment comprising a second optical element (1a).

Description

title

[0001] Screen with switchable light filter Technical field of the invention

[0002] In recent years, great strides have been made in widening the viewing angle of LCDs. However, there are often situations where the very large viewing area of ​​a screen can be a disadvantage. Information, such as banking details and other personal and sensitive data, is also becoming increasingly available on mobile devices such as notebooks and tablet PCs. Accordingly, people need control over who can see this sensitive data. They must be able to choose between a wide viewing angle – a public mode – in order to share information on their display with others, e.g., when looking at holiday photos or for advertising purposes. On the other hand, they need a narrow viewing angle – in a private mode – if they want to keep the image information confidential.

[0003] A similar problem arises in vehicle construction: The driver must not be distracted by image content, such as digital entertainment programs, when the engine is running, while the passenger also wants to consume these while driving. Therefore, a screen that can switch between the corresponding display modes is required.

[0004] Additional films based on micro-louvres have already been used for mobile displays to achieve visual privacy. However, these films were not switchable or reversible; they always had to be applied and removed manually. They also had to be transported separately from the display when not in use. A major disadvantage of using such louvre films is the associated light loss.

[0005] US Pat. No. 6,765,550 B2 describes such a privacy screen using micro-louvres. The biggest disadvantage here is the mechanical removal or installation of the filter, as well as the loss of light in protected mode.

[0006] US Pat. No. 5,993,940 A describes the use of a film with evenly spaced, small, strip-shaped prisms on its surface to achieve a private mode, i.e., a restricted viewing mode with a narrow viewing angle range. Development and production are technically quite complex.

[0007] In WO 2012 / 033583 A1, switching between unobstructed and restricted view is achieved by controlling liquid crystals between so-called "chromonic" layers. This results in light loss and requires considerable technical effort.

[0008] US 2012 / 0235891 A1 describes a very complex backlight in a screen. According to Figs. 1 and 15, not only multiple light guides are used, but also other complex optical elements such as microlens elements 40 and prism structures 50, which transform the light from the rear illumination on its way to the front illumination. This is expensive and technically complex to implement and also involves light loss. According to the variant shown in Fig. 17 in US 2012 / 0235891 A1, both light sources 4R and 18 produce light with a narrow illumination angle, with the light from the rear light source 18 first being converted at great expense into light with a wide illumination angle. This complex conversion, as already mentioned above, significantly reduces brightness.

[0009] According to JP 2007-155783 A, special optical surfaces 19 are used, which are complex to calculate and manufacture, and which then deflect light into different narrow or wide areas depending on the angle of incidence. These structures resemble Fresnel lenses. Furthermore, there are interference edges that deflect light in undesirable directions. Thus, it remains unclear whether truly meaningful light distributions can be achieved.

[0010] US 2013 / 0308185 A1 describes a special light guide with steps that emits light over a large area in different directions, depending on the direction from which it illuminates from a narrow side. In conjunction with a transmissive image display device, such as an LCD, a screen can be created that can be switched between free and restricted viewing modes. A disadvantage of this is that the restricted viewing effect can only be created for left / right or up / down, but not for left / right / up / down simultaneously, as is necessary for certain payment transactions, for example. Furthermore, even in restricted viewing mode, residual light is still visible from blocked viewing angles.

[0011] The applicant's WO 2015 / 121398 A1 describes a screen with two operating modes, in which scattering particles are present in the volume of the corresponding light guide for switching between the operating modes. However, the polymer scattering particles selected there generally have the disadvantage that light is coupled out of both large surfaces, causing approximately half of the useful light to be emitted in the wrong direction, namely toward the backlight, where it cannot be adequately recycled due to the design. Furthermore, the polymer scattering particles distributed in the volume of the light guide can, under certain circumstances, particularly at higher concentrations, lead to scattering effects that reduce the privacy effect in the protected operating mode.

[0012] The approach of "Electrical Birefringence (EDB)" technology is based on the idea of ​​using the switchable liquid crystals of an additionally applied LC panel to "filter" all light rays that do not exit the imaging layer at a specific beam angle. Disadvantages of this technology include high additional energy and cost requirements and the difficult-to-change + / -40 0 Sweet spot, i.e. the best possible viewing position. The absorption coefficient of the LC structures is also insufficient, since the attenuation of the light intensity increases again for viewing angles greater than the sweet spot, so that the light intensity for viewing angles greater than + / -40 0 up to 3% of the maximum light intensity.

[0013] Furthermore, DE 10 2020 006 110 B3 of the applicant discloses a switchable light filter and a display screen with such a switchable light filter. However, this document does not provide any information on preventing possible moiré effects in designs with partial switching.

[0014] Finally, a yet unpublished application by the applicant, DE 102023 114 957.1, describes a switchable light filter and a display with such a switchable light filter. This application also provides no information on preventing possible moiré effects in designs with partial switching.

[0015] The aforementioned methods and arrangements generally have the disadvantage that they significantly reduce the brightness of the basic screen and / or require a complex and expensive optical element for mode switching and / or reduce the resolution in the freely viewable, public mode and / or have visual artifacts on very high-resolution displays. Description of the invention

[0016] The object of the invention is therefore to describe a screen with a switchable light filter. The switchable light filter should be inexpensive to implement and, in particular, universally usable with different screen types in order to enable switching between a privacy screen - e.g., one that exists horizontally with respect to a standing or sitting viewer - i.e. a restricted viewing mode, and a free viewing mode, wherein the resolution of such a screen should not be reduced, not even slightly. Good image quality should be achieved, in particular with no or imperceptible moiré effects between the screen's image generator and the switchable light filter, which is arranged in front of or behind such an image generator.

[0017] This object is achieved according to the invention in a first embodiment by a screen with an image generator which, for displaying image content, has a first grid with pixels P B iid, further comprising a first switchable light filter, in turn comprising a first optical element, particularly preferably in turn comprising • a multitude of light-absorbing transition dipole moments, • wherein the majority of the transition dipole moments are permanently or at least in a first state with a tolerance of maximum 20° parallel to a is aligned with the first preferred direction selectable for the first optical element or varies around it, • so that light incident on the first optical element is transmitted or at least partially absorbed depending on its polarization state and its direction of incidence relative to the first optical element, Means for selectively generating at least one first electric field EF1 or one second electric field EF2, which are divided into a second grid of pixels PLC, a liquid crystal layer arranged in front of or behind the first optical element, on which the electric field generated at the respective pixels PLC acts - usually pixel by pixel - and which, depending thereon, influences the polarization state of light passing through it - usually pixel by pixel - so that the transmission properties of the first switchable light filter differ between a first operating mode B1 at corresponding pixels PLC to which the first electric field EF1 is applied, and a second operating mode B2 at corresponding pixels PLC to which the second electric field EF2 is applied, wherein explicitly either the first or the second electric field or a different electric field can be applied to all pixels PLC,which typically assumes a numerical value between the numerical values ​​of the first and second electric fields EF1 and EF2, wherein the first and the second grid differ in at least one of the parameters - preferably in at least two of the parameters, alternatively in at least three of the parameters - resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes of the grids, orientation of the coordinate axes (implementable e.g. in two 90° grids which are rotated relative to each other) and / or number of the respective pixels PLC and / or P, B iid, and optionally wherein, upon parallel projection of the second raster onto the first raster along the perpendicular bisector to the first raster, less than 50% of the edges of pixels PLC of the second raster point to any edge of pixels P B iid of the first grid, thereby reducing visually visible overlaps between the imager and other components of the screen. In an alternative, the first optical element comprises a plurality of light-absorbing transition dipole moments, • wherein the majority of the transition dipole moments are permanently or at least in a first state with a tolerance of maximum 20° parallel to a first preferred direction selectable for the first optical element or vary around this, • so that light which is incident on the first optical element is transmitted or at least partially absorbed depending on its polarization state and its direction of incidence relative to the first optical element.

[0018] The first grid can advantageously be divided into rows and columns. The first and second grids can each have any grid shape. The perpendicular bisector of the parallel projection is any perpendicular, so the perpendicular bisector is synonymous with the perpendicular.

[0019] The second grid is preferably, but not necessarily, structured in rows and columns; however, it could also be just rows or just columns.

[0020] Rows and columns of the first and / or second grid are preferably arranged at an angle of 90° to one another. Different angles of 20° to approximately 160° are also possible. The respective rows of a first and / or second grid are preferably arranged parallel to one another. The respective columns of a first and / or second grid are preferably arranged parallel to one another. Other configurations are possible, for example, if the columns and / or rows are not aligned along a straight line.

[0021] Rows and / or columns, in particular of the first and / or second grid, preferably of the grid shape of the first and / or second grid, can be formed as lines, in particular as straight lines, sinusoidal, stepped, sawtooth-shaped lines, or even curved lines. The grid shape of the first and / or second grid is preferably formed in a flat plane.

[0022] It is particularly preferred if the means for selectively generating at least one first electric field EF1 or a second electric field EF2, which is divided into a second grid, comprise an optically transparent, electrically conductive layer in grid form, in particular the Raster form comprises pixel positions. The raster form preferably encompasses all pixel positions occurring in the raster. A preferred raster form is an orthogonal raster.

[0023] The grid shape, especially for the first and / or second grid, describes the totality of all pixel positions within the grid. In many cases, grid shapes using perpendicular rows and columns are common in display technology. However, the grid shape can also deviate from this, for example, if rows and / or columns are honeycomb, sinusoidal, or stepped.

[0024] A first optical element can, for example, be formed as a laminate of layers of polymer film polarizers. Other manufacturing variants and material designs are of course possible. Alternatively, or in combination, a first optical element can also be produced by photoalignment of molecules or particles.

[0025] The transition dipole moment—also known as the transition matrix element—is a quantum-mechanical vector quantity associated with a specific transition between an initial state—usually the ground state—and a final state—usually an excited state—of a system, i.e., an atom, molecule, or solid. It corresponds macroscopically to the electric dipole moment associated with this transition. The direction of the vector defines the polarization of the transition, which in turn determines how the system interacts with an electromagnetic wave of a given polarization, for example, how it absorbs light of the corresponding polarization direction during the transition from the ground state to the excited state. The magnitude of the vector corresponds to the strength of the interaction or the transition probability.

[0026] The first preferred direction corresponds to the orientation of the transition dipole moments for a given propagation direction of light, for which the absorption is the same for any polarization direction of the light.

[0027] As materials within the meaning of the invention, which contain fixed or - for the second embodiment of second switchable light filters described below - alignable transition dipole moments, for example, dichroic dyes or dye mixtures come into consideration, which with a They can be combined with a carrier material that impairs the luminescence, for example, with liquid crystals or polymers. The optical element can, for example, contain only one dye. However, several dyes, i.e., dye mixtures, can also be contained in a single optical element. These materials relax essentially through non-radiative processes.

[0028] The extinction of light is essentially due to absorption and depends on the absolute number of transition dipole moments—and thus inherently also on the layer thickness in which the transition dipole moments are located—and the alignment between the transition dipole moment and the polarization of the incident light. Depending on the implementation, the density of said transition dipole moments, their strength, or the refractive index can vary within the layers of the respective optical element. In a passive, i.e., non-switchable, first optical element, the volume density of the transition dipoles can approach 100%.

[0029] For the simplified modeling of transmission, it is assumed that the transition dipole moments in the respective optical element, in particular in the first or second optical element, are oriented parallel to the plane of incidence of the light onto the respective optical element. The plane of incidence refers to a plane in which the direction of propagation of the light wave lies, whereby the surface of the respective optical element and the plane of incidence form a right angle. The light wave, as a transverse wave, has a transverse-magnetic oscillation component and a transverse-electric oscillation component, which - depending on the medium penetrated - are usually at least approximately both perpendicular to each other and perpendicular to the direction of propagation. Light that strikes the respective optical element is initially unpolarized in its entirety as light waves, i.e.The oscillation directions of the transverse electric—and, accordingly, the transverse magnetic—components are randomly distributed. Upon striking the surface of the optical element in question, with its transition dipole moments oriented perpendicular to the surface of the optical element, the light interacts with the optical element in question or with the transition dipole moments of the material it contains and is polarized. The oscillation components lying in the plane of incidence are absorbed. Light polarized parallel to the plane of incidence, i.e., transverse magnetic or p-polarized, is absorbed, whereas light polarized parallel to the plane of incidence, i.e., transverse magnetic or p-polarized, is absorbed. However, light that is polarized perpendicular to the plane of incidence—that is, parallel to the surface of the optical element—is either transversely electric or s-polarized, and is either completely transmitted or absorbed to a significantly reduced extent. Unpolarized light that does not pass through the optical element in question parallel to transition dipole moments is at least partially s-polarized when passing through the optical element in question with transition dipole moments aligned parallel to the plane of incidence of the light.

[0030] This property is essential for all embodiments of the invention. The transmission of p-polarized light with an incident intensity I0(a) is modeled below. The transmission of light through an absorbing layer is described by the Lambert-Beer law:

[0031] T(a) = e -d(a) Ni a a bs(“).

[0032] Here, a is the angle between the propagation direction and the surface normal, d(a) is the optical path length depending on the propagation direction, Ni is the number of absorbing molecules per volume and a abs (a) the absorption cross section as a function of the angle of incidence. Using Snell's law of refraction, the propagation angle in the medium a can be calculated from the angle of incidence ß. This gives:

[0034] The absorption cross section for each molecule or dipole moment follows Malus' law, meaning the smaller the angle between the electric field and the dipole moment, the higher the absorption. In addition, there is absorption by (undesirably) non-aligned molecules that absorb light under normal incidence and s-polarized light. The factor 1 / 3 used below results from the arbitrary orientation of the dyes relative to the incident light. For the calculation, all possible orientations between the incident electric field and the incident light must be summed. Thus, the transmission for p-polarized light with volume density N2 for the non-aligned dyes is:

[0036] The equation can also be written as

[0038] For the transmission of s-polarized light, the summand with Ni or yi is omitted. Here, parameter 71 determines the privacy, and y2 the transmission of s-polarized light as well as the transmission at normal incidence. yi / v2 is a measure of the alignment of the dyes and determines the performance of a first (or a second—defined in more detail below) optical element. Due to technological limitations, ratios of 10–100 are often achieved, but other values ​​are possible.

[0039] The object of the invention is further achieved by a second embodiment of a screen with an image generator which, for displaying image content, is divided into a first grid with pixels Psiid, in particular pixels Pßiid arranged in rows and / or columns, further comprising a second switchable light filter, in turn comprising a second optical element which i. comprises a plurality of light-absorbing transition dipole moments which are in the form of molecules of one and / or in the form of one or more dichroic dyes, ii. wherein the majority of the transition dipole moments are aligned at least in a first state with a tolerance of maximum 20° parallel to a first preferential direction selectable for the second optical element or vary around this, iii.so that light incident on the second optical element is transmitted or at least partially absorbed depending on its polarization state and its direction of incidence relative to the second optical element, iv. wherein the transition dipole moments are embedded in a liquid crystal layer, so that the orientation and / or magnitude of the transition dipole moments can be varied between the first and at least one second state in order to be able to alternatively place the second optical element into at least two different states. Means for selectively generating at least a first electric field EF1 or a second electric field EF2, which are divided into a second grid of pixels PLC, , - wherein the transmission properties of the second switchable light filter differ between a first operating mode B1 at corresponding pixels PLC, at which the first electric field EF1 is applied to the liquid crystal layer, and a second operating mode B2 at corresponding pixels PLC, at which the second electric field EF2 is applied to the liquid crystal layer, wherein explicitly either the first or the second electric field or another electric field can be applied to all pixels PLC, which typically assumes a numerical value between the numerical values ​​of the first and second electric fields EF1 and EF2, - wherein the first and the second grid differ in at least one of the parameters, preferably in at least two of the parameters, alternatively in at least three of the parameters, resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes of the grids, alignment of the coordinate axes and / or number of the respective pixels PLC or Pßiid, and optionally - wherein, upon parallel projection of the second grid onto the first grid along the perpendicular bisector to the first grid, less than 50% of the edges of pixels PLC of the second grid are projected onto any edge of pixels Pßiid of the first grid, thereby reducing visually visible overlaps of the imager and other components of the screen. In particular, wherein the first electric field EF1 is applied to the liquid crystal layer and / or the second electric field EF2 is applied to the liquid crystal layer. Preferably, the transmission properties of the second switchable light filter can be adjusted differently between a first operating mode B1 and a second operating mode B2 at corresponding pixels PLC by applying a first and / or second electric field (EF1 / EF2).

[0040] The above second grid is preferably, but not necessarily, structured in rows and columns; however, it could also be just rows or just columns. The alignment of the coordinate axes can be implemented, for example, in two 90° grids that are rotated relative to one another. The first and second grids are typically arranged plane-parallel to one another. Other arrangements, such as tilted relative to one another, are also within the scope of the invention. The transition dipole moments can - as described above - be formed as one dichroic dye or as several dichroic dyes, thus by such dye molecules, which are integrated into liquid crystals of the liquid crystal layer in a guest-host arrangement. In the second embodiment, the dye molecules in turn are then aligned parallel to the liquid crystal molecules of the liquid crystal layer.The alignment of the liquid crystal molecules in a voltage-free electric field is in turn induced by the surfaces that bound them. One possible material for such surfaces is PMI.

[0041] Pixel PLC can also be referred to as second pixels. P B iid can be called the first pixels.

[0042] In general, we can speak of liquid crystal polymers doped with dye(s). Various approaches are known in the art (e.g., thermosettling LCs and epoxy LCs), which will therefore not be discussed in detail. The following publications are examples in this context:

[0043] N. Saba, M. Jawaid, OY Alothman, MT Paridah, and A. Hassan, “Recent advances in epoxy resin, natural fiber-reinforced epoxy composites and their applications,” Journal of Reinforced Plasticsand Composites, vol. 35, no. 6, 2015.

[0044] C. Carfagna, E. Amendola, and M. Giamberini, “Liquid crystalline epoxy based thermosetting polymers,” Progress in Polymer Science, vol. 22, pp. 1607-1647, 1997.

[0045] V. P. Shibaev and A. Yu. Bobrovsky, “Liquid crystalline polymers: development trends and photocontrollable materials,” Russian Chemical Reviews, vol. 86, pp. 1024- 1072, 2017.

[0046] T. Ikeda, J.-i. Mamiya, and Y. Yu, “Photomechanics of liquid-crystalline elastomers and other polymers,” Angew. Chem. Int. Ed., vol. 46, pp. 506-528, 2007.

[0047] The at least one dye consists of dye molecules, wherein a transition dipole or transition dipole moment is advantageously associated with each dye molecule, i.e. each dye molecule corresponds to a transition dipole or transition dipole moment. Typically, a dye has a mass fraction of 0.01% to 10% (or possibly significantly more), preferably of 0.1% to 5%, of the material of the respective layer(s) in the first or second optical element. The thickness of the layers is preferably in the range from 0.2 pm to 50 pm, more preferably in the range from 0.5 pm to 20 pm, all boundary values ​​included. The dyes or dye mixtures in the first and second optical element can also be formed differently in their different layers, if present.

[0048] In the second embodiment, a preferred embodiment for each layer is a mixture of liquid crystals with at least one dye, especially with at least one dichroic dye mixture. Examples of dichroic dyes or dye mixtures that can be used are azomethine dyes, indigoid and thioindigoid dyes, merocyanines, azulene, quinophthalone dyes, perylene dyes, phthaloperine dyes, dioxazine dyes, triphenodioxazine dyes, Quinoxaline dyes, triazine dyes, tartrazine, azo dyes, and anthraquinone dyes are suitable. The preparation of a liquid crystal dye mixture is described, for example, in US Pat. No. 4,695,131. Furthermore, the outer surfaces of the layers are preferably treated, for example, brushed, to achieve a homogeneous surface alignment of the transition dipole moments or, if present, of the liquid crystals.

[0049] The mode of operation of the measures according to the invention for all embodiments is explained in more detail below: Due to the fact that the first and the second grid differ in at least one of the parameters, preferably in at least two of the parameters, alternatively in at least three of the parameters, in particular resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes of the grids, alignment of the coordinate axes and / or number of the respective pixels PLC and / or Pßiid of the two grids, in particular, overlaps of local or overall areas of the first and the second grid are reduced or completely prevented. The parameters are preferably selected from the above parameters. In this way, periodic brightness fluctuations are suppressed. In particular, visually visible overlaps of the image generator and other components in the screen are reduced or even completely avoided. This therefore helps The invention aims to avoid moiré effects. This can be implemented using an alternative method in which the coordinate axes of two 90° grids are rotated relative to each other.

[0050] Alternatively, at least partial or complete non-periodicity of the respective pixels can be used in one or both grids. This is also useful for combating visually visible overlaps, but requires a corresponding transformation of the image geometry to the pixel geometry when controlling the respective grid or both grids, especially in the first grid, to prevent distorted image content from being perceived.

[0051] Both the first and the second embodiment of a screen in question can further be implemented such that the number of pixels PLC of the second grid is smaller than the number of pixels P Biid of the first raster. It is advantageous if the number of pixels PLC of the second raster is even smaller by a factor of 2, 5, 10, 50 or more than 100 than the number of pixels P B iid of the first grid. This circumstance helps avoid visually visible overlaps between the two grids, because the periods of the grids, if present, are usually different, and the period of the second grid is usually not an integer multiple of the first grid.

[0052] Furthermore, it is possible for the first and second grids to differ at least in the base angle of their coordinate axes, with the coordinate axes of the second grid forming an angle of greater than or equal to 45° to less than or equal to 88°, in particular between 45° and less than 88°, preferably between 60° and 85°, relative to one another, while the coordinate axes of the first grid form an angle of greater than or equal to 88° and less than or equal to 92°, in particular between 88° and 92°. This defined rotation also helps to suppress visually visible overlaps between the two grids.

[0053] Furthermore, it can be advantageous if the pixels PLC of the second grid are parallelogram-shaped or otherwise non-square. For example, non-square pixels can be provided with rounded edges. For example, if the meshes of the first grid correspond to the pixels P B iid, then such a pixel P Biid typically be rectangular, square, parallelogram or diamond-shaped. It should be noted here that the term pixel is used for simplicity refers to a smallest area (possibly separated by color, i.e. color supixels) that can be separately controlled with a partial image content, whereby a non-luminous or non-transmitting area, e.g. a black matrix, is included, so that the first grid is completely filled with the pixels (hole-free). In the event that the actual light-emitting or light-transmitting aperture of such a pixel P B If iid were taken into consideration, significantly more complex geometries would be conceivable, as documented at https: / / lcdtech.info / en / tests / lcd.pixels.structure.htm.

[0054] The Pixel P B iid of the first raster can be designed, for example, as monochrome or as color subpixels (e.g. RGB or RGB-white).

[0055] Within the meaning of the invention, it is also conceivable that at least two pixels PLC of the second grid have a different size and / or shape from one another. Different sizes can mean both the largest dimensions of such second pixels Pixel PLC and their surface area. If two pixels Pixel PLC differ in size, then their largest dimensions and / or their surface areas vary by at least 3%. If, on the other hand (or additionally), they differ in shape, this means that they cannot be made congruent even by linear size scaling. This is basically also possible for the first grid. Furthermore, the second grid should have at least two pixels PLC so that the measures according to the invention can be implemented.

[0056] Preferably, in parallel projection of the second grid onto the first grid along the perpendicular bisector to the first grid, less than 50%, preferably less than 20%, particularly preferably less than 5%, of the edges of pixels PLC of the second grid onto any edge of pixels P B iid of the first grid. This geometric condition also helps avoid moiré effects and other visually visible overlays.

[0057] In a preferred embodiment, a polarization filter is also present, which can be arranged upstream or downstream of the first optical element in the direction of incidence. Such a polarization filter preferably transmits horizontally linearly polarized light.

[0058] The means for selectively generating at least a first electric field EF1 or a second electric field EF2, which is distributed in a second grid The second grid is divided into PLC pixels, and in both embodiments, the first layer can comprise at least two conductive layers, in particular two optically transparent, electrically conductive layers, preferably, for example, ITO layers, which are connected to a signal generator, wherein at least one of the two conductive layers is divided into PLC pixels according to the second grid. The respective conductive layers are each preferably, but not necessarily, located in a planar plane.

[0059] The means for selectively generating at least a first electric field EF1 and / or a second electric field EF2 preferably comprise one or more, in particular two or more, optically transparent, electrically conductive layers, in particular an oxide or oxides, preferably a metal oxide or metal oxides, such as oxides of semimetals synonymous with oxides of semiconductor metals, in particular oxides of one or more transition metals. Examples of layers of these oxides are ITO layers (indium tin oxide), IZO layers (indium zinc layer), ATO layers (antimony-doped tin oxide), FTO, SnO2:F (fluorine-doped tin oxide), AZO, ZnO:Al (aluminum-doped zinc oxide), or mixtures thereof. The oxides of the metals can be doped with foreign metals and / or halogens. A foreign metal is considered to be a metal other than the oxides of the metals.The liquid crystal layer 3 is preferably arranged between the optically transparent, electrically conductive layers of an oxide or oxides. Alternatively, the device may also comprise one or more thin-film transistors (TFTs).

[0060] A particularly preferred means for selectively generating at least a first electric field EF1 and / or a second electric field EF2 comprises, independently of one another, or is selected from one or more optically transparent, electrically conductive layers divided into a second grid of pixels PLC. A layer with a second grid of pixels PLC is preferably selected from the group of an oxide or oxides, preferably a metal oxide or metal oxides.

[0061] Preferably, means are selected from transparent, electrically conductive oxide layers. The means for selectively generating at least one first electric field EF1 or one second electric field EF2 may comprise two or more transparent ITO layers (indium tin oxide, as known in the art) between which the liquid crystal layer 3 is arranged. These ITO layers may be connected to a signal generator, which may be used as needed for the first electric field EF1 or the second electric field EF2 generates a direct current or preferably an alternating current signal, for example a sinusoidal or rectangular (or other) electrical signal. As a result, the ITO layers then have the respective first electric field EF1 or second electric field EF2, which influences the state of the liquid crystals of the liquid crystal layer 3. In an exemplary embodiment, the signal used for the first mode B1 is rectangular or sinusoidal with a frequency of 40 Hz to 10 kHz, preferably 64 Hz to 1 kHz, and the maximum applied voltages are between -20 V and +20 V. In the second mode, the second electric field EF2 can have a field strength of 0 V / m, i.e. it can be field-free. Alternatively, the assignment of the field-free state for the first mode can be B1 and the second mode B2 represents a non-field-free state.

[0062] Other embodiments are possible, for example, using the same principles used in FFS (fringe filed switching) or IPS (in-plane switching) LCD panels to control their pixels. However, the invention is not limited to the aforementioned embodiments and merely provides possible examples of exemplary embodiments of the invention.

[0063] Furthermore, the means for selectively generating at least a first electric field EF1 or a second electric field EF2 should be designed such that they generate the first electric field EF1 and the second electric field EF2 simultaneously, but at different locations of the switchable light filter 5, in order to thereby enable partial switching of the switchable light filter 5 to different operating modes.

[0064] The means for selectively generating at least a first electric field EF1 or a second electric field EF2 can also be designed by a person skilled in the art in such a way that they generate not only a first electric field EF1 and a second electric field EF2, but optionally also further third, fourth, etc. electric fields EF3, EF4, etc., in order to enable additional operating modes for the entire area of ​​the switchable light filter or only partially.

[0065] Furthermore, it is advantageous to use the above-described screen of the first or second embodiment in such a way that at corresponding pixels PLC to which the first electric field EF1 is applied, in a first operating mode B1, on the one hand, linearly or elliptically polarized light (in particular in the case of elliptically polarized light, the ratios of the semi-axes should be at least 1:4, better at least 1:10 or greater), which originates from the imager and is incident parallel to the first preferred direction into the switchable light filter, in particular into the first or second switchable light filter, is transmitted to at least 24%, and on the other hand, linearly or elliptically polarized light, which originates from the imager and is incident at at least a first angle of more than 35° to the first preferred direction, which lies in a first plane, into the switchable light filter, in particular into the first or second switchable light filter, is absorbed to at least 85%, at corresponding pixels PLC to which the second electric field EF1 is applied,In a second operating mode B2, on the one hand, linearly or elliptically polarized light originating from the imager and incident parallel to the first preferred direction into the switchable light filter, in particular into the first or second switchable light filter, is transmitted to at least 24%, and on the other hand, linearly or elliptically polarized light originating from the imager and incident at at least a second angle of more than 35° to the first preferred direction, which lies in a second plane, into the switchable light filter, in particular into the first or second switchable light filter, is absorbed to at least 85%, wherein the first and second planes intersect at an angle of 80° to 100°, so that the directions of (main) absorption for the first operating mode B1 and the second operating mode B2 differ by 80° to 100°, respectively.

[0066] Said first preferred direction can advantageously enclose an angle between 0° and 45° inclusive with a surface normal of the first or second optical element. Furthermore, in special embodiments, the first preferred direction can vary across the surface of the first or second optical element. For the purposes of the invention, the first preferred direction averaged over the surface then applies. The subject of the invention can also be a screen with an image generator which, for displaying image content, has a first grid Ra with pixels P B iid, may further comprise a first switchable light filter, in turn comprising - a first optical element, - means for selectively generating at least a first electric field EF1 or a second electric field EF2, which are divided into a second grid of pixels PLC, - a liquid crystal layer arranged in front of or behind the first optical element, on which the electric field generated at the pixels PLC acts and which, depending thereon, influences the polarisation state of light passing through it, so that - wherein the transmission properties of the switchable light filter differ between a first operating mode B1 at corresponding pixels PLC to which the first electric field EF1 is applied, and a second operating mode B2 at corresponding pixels PLC to which the second electric field EF2 is applied, - wherein the first and the second raster Ra, Rb differ in at least one of the parameters resolution, pixel shape, pixel size, raster shape, base angle of the coordinate axes R1, R2 of the two rasters Ra, Rb, orientation of the coordinate axes R1, R2 and / or number of the respective pixels PLC or P B iid distinguish, and - wherein, upon parallel projection of the second raster Rb onto the first raster Ra along the perpendicular bisector to the first raster Ra, less than 50% of the edges of pixels PLC of the second raster Rb onto any edge of pixels P Bi id of the first raster Ra, thereby reducing visually visible overlaps between the imager and other components of the screen. Wherein, in an alternative, the first optical element can comprise a) itself a plurality of light-absorbing transition dipole moments DP1, DP2, wherein the majority DP1 of the transition dipole moments can be permanently or at least in a first state with a tolerance of maximum 20° parallel to a first preferential direction that can be selected for the first optical element or can vary around this, so that light that is incident on the first optical element, depending on its polarization state and its Incidence direction relative to the first optical element can be transmitted or at least partially absorbed, or b) a linear polarization filter, in particular which can transmit or at least partially absorb light depending on its polarization state and / or its incidence direction, wherein the polarization direction with maximum transmission can be selected for the linear polarization filter.

[0067] With regard to alternative b) with a linear polarization filter, in particular a screen with an image generator which uses a first grid with pixels P to display image content can be used. B iid, further comprising a first switchable light filter, in turn comprising, - as a first optical element, a linear polarization filter which transmits or at least partially absorbs light depending on its polarization state and / or its direction of incidence, wherein the polarization direction with maximum transmission can be selected for the linear polarization filter, - means for selectively generating at least a first electric field EF1 or a second electric field EF2, which are divided into a second grid of pixels PLC, - a liquid crystal layer arranged in front of or behind the linear polarisation filter, on which the electric field generated at the pixels PLC acts and which, depending on this, influences the polarisation state of light passing through it, so that - the transmission properties of the switchable light filter differ between a first operating mode B1 at corresponding pixels PLC to which the first electric field EF1 is applied, and a second operating mode B2 at corresponding pixels PLC to which the second electric field EF2 is applied, - wherein the first and the second grid differ in at least one of the parameters resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes of the two grids, orientation of the coordinate axes and / or number of the respective pixels PLC or Pßiid, and

[0068] - wherein, upon parallel projection of the second raster onto the first raster along the perpendicular bisector to the first raster, less than 50% of the edges of pixels PLC of the second raster point to any edge of pixels P Biid of the first grid, thereby reducing visually visible overlaps between the imager and other components of the screen.

[0069] In a preferred embodiment, a polarization filter P is also present, which can be arranged upstream or downstream of the first or second optical element in the direction of incidence. Alternatively, a λ / 4 retardation layer can also be present to generate linearly polarized light from circularly polarized light, if necessary, depending on the properties of the light originating from a corresponding light source, i.e., the corresponding imager.

[0070] In order to switch the optical effect of the second switchable light filter according to the invention, in the second embodiment of the invention, the transition dipole moments in each layer are varied in their orientation and / or their magnitude between the first and at least one second state in order to be able to alternatively place the respective layer into at least two different states. Possible embodiments of a second optical element or of each layer therein are based, for example, on liquid crystals and / or dyes or dye mixtures, which are arranged in the said liquid crystal cell with homogeneous alignment on the surfaces and can be rotated therein between at least two states. In this case, the light-absorbing transition dipole moments are also rotated and can thus assume at least two effective states. It is particularly conceivable in such embodiments that more than two states, e.g.Three or eight states, each with different optical effects, can be achieved. Other configurations of the liquid crystal cells are also conceivable. For this purpose, electric fields EF1, EF2, etc., are used, in particular, to rotate the liquid crystals. It is possible, for example, for either a first electric field or a second electric field to describe a field-free state, with the other electric field having an absolute field strength greater than zero, e.g., 0.5 MV / m, and changing dynamically to prevent charging of the liquid crystals.

[0071] A first such state corresponds to the conditions described above and at least a second state is different from this, i.e. has at least one other preferred direction.

[0072] For such active, i.e., second switchable, light filters, volume densities of the transition dipole moments between 0.1% and 90% based on liquid crystals in the second optical element are conceivable. Alternatively, configurations of a second optical element or each layer therein are conceivable in which the transition dipole moments are embedded in a liquid subjected to an electrowetting process. In this way, the density of the transition dipole moments can be varied, in particular, but not exclusively.

[0073] Furthermore, it is possible for the means for selectively generating at least one first electric field EF1 or one second electric field EF2 to also selectively generate third, fourth or further electric fields different therefrom at pixels PLC of the second grid, so that third, fourth and optionally further states can be generated for the liquid crystal layer, which then in turn cause third, fourth and optionally further absorption or transmission characteristics of the (first or second) switchable light filter at locations of the pixels PLC of the second grid in previously described screens.

[0074] Furthermore, a first or second switchable light filter can be extended by a further first optical element identical in construction to the first optical element (or with a different preferred direction), between which the respective liquid crystal layer is located. This makes it possible, among other things, to selectively switch angular restrictions in the transmission between one (e.g., angular restrictions only horizontal) and two directions (e.g., angular restrictions horizontal and vertical).

[0075] In a similar way, the second configuration of a switchable light filter can also be supplemented with a second liquid crystal layer identical in construction to the (first) liquid crystal layer. This makes it possible, for example, to selectively switch angular restrictions in the transmission between no, one, or two directions.

[0076] The invention also relates to a screen with an image generator, in particular as an intermediate product of a screen according to claim 1 or for producing a screen according to claim 1 which comprises a first switchable light filter which, for displaying image contents, has a first grid (Ra) with pixels P B iid, continues to be comprehensive Means for selectively generating at least one first electric field EF1 or one second electric field EF2, which are divided into a second grid Rb with pixels PLC, a liquid crystal layer arranged on or between the means for selectively generating at least one first electric field EF1 or one second electric field EF2, on which the electric field generated at the pixels PLC acts and which, depending thereon, influences the polarization state of light passing through it, wherein the first and the second grid Ra, Rb differ in at least one of the parameters resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes R1, R2 of the two grids, alignment of the coordinate axes R1, R2 and / or number of the respective pixels PLC or P B iid distinguish, and

[0077] wherein, upon parallel projection of the second raster Rb onto the first raster Ra along the perpendicular bisector to the first raster Ra, less than 50% of the edges of pixels PLC of the second raster Rb are projected onto any edge of pixels Pßiid of the first raster Ra, thereby reducing visually visible overlaps of the image generator and other components of the screen. The invention also encompasses the use of a screen as described above with a first optical element, in turn comprising i. a plurality of light-absorbing transition dipole moments DP1, DP2, ii. wherein the majority DP1 of the transition dipole moments is permanently or at least in a first state aligned with a maximum tolerance of 20° parallel to a first preferential direction selectable for the first optical element or varies around this, iii.such that light incident on the first optical element is transmitted or at least partially absorbed depending on its polarization state and its direction of incidence relative to the first optical element. such that the polarization properties of the light incident from the imager onto the first optical element differ between a first operating mode B1 at corresponding pixels PLC to which the first electric field EF1 is applied, and a second operating mode B2 at corresponding pixels PLC to which the second electric field EF2 is applied.

[0078] For the first and second optical elements of the first and second embodiments, it may further be the case that the respective preferred direction of a transition dipole moment can be selected depending on its position on the respective optical element.

[0079] In this context, it can be particularly useful for each first or second optical element to be divided into different regions (A1, A2, ...) along a selectable reference line on the respective first or second optical element, wherein a separate region preferred direction can be selected for each region (A1, A2, ...), which applies to all transition dipole moments of the corresponding first or second optical element lying within a region (A1, A2, ...), wherein all region preferred directions are different in pairs and point in the direction of an observer up to a tolerance of maximum + / - 10 degrees. Within an optical element and within each region applicable to it, all transition dipole moments are therefore aligned parallel to the preferred direction applicable there, with a tolerance of maximum + / - 10°.

[0080] Advantageously, the imager corresponds to an LCD panel, one of whose polarization filters corresponds to the polarization filter of the first or second switchable light filter. This can be the front or rear polarizer in the LCD structure. Furthermore, the first or second switchable light filter can advantageously be arranged between the LCD panel and its backlight in order to switch pixel by pixel (in pixels PLC) between a first operating state for a free view mode and a second operating state for a restricted view mode, because the light from the backlight is sometimes focused and sometimes unfocused in the horizontal direction due to the switchable light filter - for example, when switching in the horizontal direction. "Focusing" does not mean focusing like a lens, but rather a narrowing of the emission range or transmission range across the angles.

[0081] In contrast, the first or second switchable light filter can also be arranged in front of the LCD panel in the viewing direction.

[0082] The imager can alternatively be an OLED, a SED display, a field emission display (FED), a microLED panel, or a vacuum fluorescent display (VFD), in front of which a first or second switchable light filter is arranged. Since the described first and second switchable light filters of the display are effective regardless of the type of imager, any other display types are also possible.

[0083] Such a screen is advantageously used in a mobile device, a motor vehicle, aircraft, or watercraft, in a payment terminal, or in an access system. Switching between the aforementioned operating modes is possible either over the entire screen or by sections or pixels to protect sensitive data, i.e., to display it in a way that is perceptible to only one viewer, or alternatively, to display image content simultaneously for multiple viewers.

[0084] In principle, the performance of the invention is maintained if the parameters described above are varied within certain limits.

[0085] The invention also relates to the use of screens with image generators which have a first grid with pixels P for displaying image content. Biid, and a first switchable light filter comprising means for selectively generating at least one electric field (EF1) or a second electric field (EF2), which is divided into a second grid of pixels PLC, for reducing visually visible overlaps of the imager and other components of the screen. The invention also relates to the use of a first switchable light filter in a screen. The invention also relates to a switchable light filter (5).

[0086] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations indicated, but also in other combinations or in isolation, without departing from the scope of the present invention. Short description of the drawings

[0087] The invention is explained in more detail below using exemplary embodiments with reference to the accompanying drawings, which also disclose features essential to the invention. These exemplary embodiments are for illustrative purposes only and are not to be interpreted as restrictive. For example, a description of an embodiment with a large number of elements or components should not be interpreted to mean that all of these elements or components are necessary for implementation. Rather, other embodiments may also contain alternative elements and components, fewer elements or components, or additional elements or components. Elements or components of different exemplary embodiments may be combined with one another unless otherwise stated. Modifications and variations described for one of the exemplary embodiments may also be applicable to other exemplary embodiments.To avoid repetition, identical or corresponding elements in different figures are designated by the same reference numerals and are not explained more than once. They show: Fig.1 is a schematic diagram of a first exemplary pixel arrangement of an imager in the prior art, Fig.2 is a schematic diagram for subdividing a first exemplary pixel arrangement of an image generator into color subpixels in the prior art, Fig.3 is a schematic diagram of a second exemplary pixel arrangement of an imager, Fig.4 is a schematic diagram of a third exemplary pixel arrangement of an imager, Fig.5 is a schematic diagram of a fourth exemplary pixel arrangement (RGB pixels of the RGB color model, in particular additive color model; R: pixels, G: pixels, B: pixels) of an image generator, Fig.6 is a schematic diagram of an exemplary different alignment of the respective coordinate axes of the first (R1) and the second grid (R2), Fig.7a is a schematic diagram of an exemplary different design of the first (Ra) and the second grid (Rb), wherein the respective Coordinate axes of the first and second grid are partially aligned differently, Fig.7b is a schematic diagram of an exemplary different configuration of the first (Ra) and the second grid (Rb), wherein the respective coordinate axes of the first and the second grid are aligned in the same way, Fig.7c is a schematic diagram of an exemplary different configuration of the first (Ra) and the second grid (Rb), wherein the respective coordinate axes of the first and the second grid are aligned in the same way, Fig.8 shows an exemplary first structure of a screen, as well as Fig.9 shows an exemplary second structure of a screen. Fig. 10 Transition dipole moments DP1 of the first optical element 1 aligned within 20° to the bisector (assumed a=0°; shown here only larger than 0° so that it can be recognized). Detailed description of the drawings

[0088] The drawings are not to scale and merely depict schematic diagrams. The following embodiments are merely examples. Modifications in the arrangement and geometry of the pixels are also covered by the invention.

[0089] Figure 1 shows the schematic diagram of a first exemplary pixel arrangement of an image sensor 2 for displaying image content, using a first grid of pixels Pβiid, as known in the prior art. In this pixel arrangement, the axes are arranged perpendicular to one another, and the aspect ratio of the pixel size along the axes is 1, i.e., the pixels each have a height that corresponds to their width. This configuration is found in the prior art in most color liquid crystal displays.

[0090] Furthermore, Fig.2 shows a schematic diagram for the division of a first exemplary pixel arrangement, ie a first grid, of an image generator (according to Fig.1) into color subpixels in the prior art. Here, the pixels are in turn divided into divided into color subpixels that separately emit or transmit red (R), green (G) and blue light (B).

[0091] If a second optical grid Rb, for example a monoLCD panel with the same pixel sizes as in the first grid Ra of the image generator 2, were placed at a distance of a few 100 pm to a few millimeters above the image generator 2, unpleasant moiré effects would generally arise due to optical superposition effects of similar (or identical) grids. With this in mind, a first embodiment of a screen with an image generator 2 is described below (with reference to Figures 7a to 7c), which has a first grid Ra with pixels Pb1id for displaying image content, further comprising a first switchable light filter 5. The first switchable light filter 5 in turn comprises a first optical element 1, in turn comprising • a multitude of light-absorbing transition dipole moments, • wherein the majority of the transition dipole moments are permanently or at least in a first state with a tolerance of maximum 20° parallel to a first preferred direction that can be selected for the first optical element 1 or vary around this, Fig.10 shows some exemplary aligned dipoles DP1 as well as dipoles DP2 that are not aligned within the said tolerance (assuming a=0°; shown here only for the sake of clarity, greater than 0°), • so that light incident on the first optical element 1 is transmitted or at least partially absorbed depending on its polarization state and its direction of incidence relative to the first optical element 1, Means 4 for selectively generating at least a first electric field EF1 or a second electric field EF2, which are divided into a second grid Rb with pixels PLC (this second grid Rb is preferably, but not necessarily, structured in rows and columns; however, it could also be just rows or just columns), a liquid crystal layer 3 arranged in front of or behind the first optical element 1, on which - usually pixel by pixel - the electric field generated at the pixels PLC acts, and which, depending thereon, influences the polarization state of light passing through it - usually pixel by pixel - so that the transmission properties of the first switchable light filter 5 differ between a first operating mode B1 at corresponding pixels PLC to which the first electric field EF1 is applied, and a second operating mode B2 at corresponding pixels PLC to which the second electric field EF2 is applied, wherein explicitly either the first or the second electric field or another electric field can be applied to all pixels PLC, which typically assumes a numerical value between the numerical values ​​of the first and second electric fields EF1 and EF2, wherein the first and second grids Ra, Rb differ in at least one of the parameters - preferably in at least two of the parameters, alternatively in at least three of the parameters - resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes of the grids, orientation of the coordinate axes (implementable, for example, in two 90° grids that are rotated relative to each other) and / or number of the respective pixels PLC or P.B iid, and wherein, upon parallel projection of the second raster Rb onto the first raster Ra along the perpendicular bisector M to the first raster Ra, less than 50% of the edges of pixels PLC of the second raster Rb are projected onto any edge of pixels Pßiid of the first raster Ra, thereby reducing visually visible overlaps of the image generator 2 and other components of the screen.

[0092] The first grid Ra can advantageously be divided into rows and columns.

[0093] A first optical element 1 can be produced, for example, by photoalignment of molecules or particles. Suitable materials within the meaning of the invention that contain fixed or—for the second embodiment of second switchable light filters 1a described below—alignable transition dipole moments include, for example, dichroic dyes or dye mixtures combined with a carrier material that does not impair the properties, for example, liquid crystals or polymers.

[0094] Fig. 3 shows a schematic diagram of a second exemplary pixel arrangement of an image generator 2, first grid Ra. Here, the pixels Pιid of the first grid Ra (which in turn can be divided into color subpixels) are rectangular, but the angle between the axes deviates from 90°. Here, for example, it is 75°, but can also assume other values, for example, between 10° and 80°. A second grid Rb with pixels PLC, which is used in a previously described screen, could, for example, have rectangular axes synonymous with coordinate axes R2, as shown (but for a first grid) in Fig. 1. Thus, the first and second grids Ra, Rb differ in at least one of the above-mentioned parameters, and visually visible overlaps of the imager 2 and other components of the screen are reduced or even avoided because the first and second grids Ra, Rb differ. The larger center-to-center distance of the pixels P B In Fig. 3, iid is oriented along the vertical direction. However, in other embodiments, it can also be oriented along the other direction.

[0095] Furthermore, Fig.4 shows a schematic diagram of a third exemplary pixel arrangement for the first grid Ra with pixels P Biid of an image generator 2. A second grid Rb with pixels PLC, which is used in a previously described screen, could, for example, have axes R2 that are rectangular to one another, as shown in Fig. 1. In this example, the axes R1 of the first grid Ra are rotated by 45° relative to the second grid Rb (not shown in the drawing). Thus, the first and second grids Ra, Rb differ in at least one of the above-mentioned parameters, and visually visible overlaps of the image generator 2 and other components of the screen are reduced or even avoided because the first and second grids Ra, Rb differ.

[0096] Fig.5 shows a schematic diagram of a fourth exemplary pixel arrangement for the first grid Ra with pixels P Biid of an image generator 2. This is a possible color subpixel arrangement, for example for OLED image generators. The first grid Ra is rotated by 45° compared to the second grid Rb (not shown in the drawing). In addition, the number of different subpixels R, G, B in the first grid is not the same, ie there are as many green subpixels as red and blue ones combined. In addition, the green subpixels have a different size than the red and blue ones. A second grid with pixels PLC, which is used in a previously described screen, could, for example, have axes that are rectangular to one another, as shown in Fig.1.Thus, the first and second grids Ra, Rb differ in at least one of the above-mentioned parameters, and visually visible overlaps of the image generator 2 and other components of the screen are reduced or even avoided because the first and second grids differ.

[0097] Furthermore, Fig. 6 shows a schematic diagram of an exemplary different orientation of the respective coordinate axes R1, R2 of the first and second grids Ra, Rb. Here, the orthogonal axes R1, indicated by solid lines, represent the first grid Ra, and the orthogonal axes R2, indicated by dashed lines, represent the second grid Rb. However, the meaning can also be reversed without departing from the scope of the invention. The nearest adjacent axes R1, R2 of the first and second grids Ra, Rb each enclose an angle of approximately 30°.

[0098] In addition, Fig. 7a shows a schematic diagram of an exemplary different embodiment of the first and second grids Ra, Rb, wherein the respective coordinate axes R1, R2 of the first and second grids Ra, Rb are partially aligned differently. The orthogonal axes R1, indicated by solid lines, represent the first grid Ra with pixels Pßiid. The pixels PLC of the second grid Rb are shown by dashed lines. The pixels Pßiid of the first grid Ra are rectangular in this example, in particular square, while the pixels PLC of the second grid Rb are parallelogram-shaped. In each case one axis of the first and second grids Ra, Rb (here from the observer's point of view onto the plane of the paper, for example the horizontal axes) are parallel to one another, while the respective other axes R1, R2 of the first and second grids Ra, Rb form an angle greater than zero with one another, here for example 20° (other values ​​are possible).Thus, the first and second rasters Ra, Rb again differ in at least one of the above-mentioned parameters, and visually visible overlaps of the image generator 2 and other components of the screen are reduced or even avoided because the first and second rasters Ra, Rb differ. In particular, it can be seen here that when the second raster Ra is projected parallel to the first raster Ra along the perpendicular bisector M to the first raster Ra, less than 50% of the edges of pixels PLC of the second raster Rb are projected onto any edge of pixels Pßiid of the first raster Ra.

[0099] Fig. 7b shows a schematic diagram of an exemplary different configuration of the first grid Ra and the second grid Rb, wherein the respective coordinate axes R1, R2 of the first and second grids Ra, Rb are aligned in the same way. In particular, the number and size of the pixels PLC of the second grid Rb differ from those of the pixels P Bi | d of the first grid Ra. It can also be seen that when the second grid Ra is projected parallel to the first grid Ra along the perpendicular bisector M to the first raster Ra less than 50% of the edges of pixels PLC of the second raster Rb to any edge of pixels P B iid of the first raster Ra. Edge here refers to the edge of a boundary surface between any two nearest neighboring pixels of the same type P B iid or PLC is meant.

[0100] Fig.7c shows a schematic diagram, whereby the description of Fig.7b is to be applied accordingly.

[0101] In general, pixels Pßiid or PLC used in all screen designs can also take on non-rectangular shapes.

[0102] Fig. 8 shows an exemplary first structure of a screen comprising a means 4 of the first embodiment described above. From the viewer's perspective from back to front, such a screen comprises an image generator 2 with pixels Pβiid in a first grid Ra, for example designed as described for Figs. 3, 4, 5 or 7a-c, optionally: a linear polarization filter P a first switchable light filter 5, in turn comprising i. a flat ITO layer ITO1, ii. a liquid crystal layer 3, iii. a flat ITO layer ITO2 structured as a second grid Rb, which is provided with TFTs to form pixels PLC of the second grid Rb, and iv. a first optical element 1, as described above, wherein here, by way of example, the first preferred direction should be aligned approximately parallel to the perpendicular bisector M on the first optical element 1.

[0103] The first and second ITO layers ITO1, ITO2 form the means 4 for selectively generating at least one first electric field EF1 or one second electric field EF2, whereby they are also connected to a not shown The control electronics shown, in particular including a signal generator, are coupled, which generates defined voltages. It is possible, for example, that either a first electric field EF1 or a second electric field EF2 describes a field-free state, with the respective other electric field, in particular a dynamic electric field, having an absolute field strength greater than zero, e.g., 0.5 MV / m.

[0104] Further layers and components not shown in the drawing may be present, such as protective or cover layers made of glass and / or polymers. Such an exemplary screen according to Fig. 8 functions as described above. Due to the measures taken, namely that the first and second grids Ra, Rb differ in at least one of the parameters - preferably in at least two of the parameters, alternatively in at least three of the parameters - resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes of the grids, alignment of the coordinate axes, in particular implementable e.g. in two 90° grids that are rotated relative to each other, and / or number of the respective pixels PLC or P B iid, visually visible overlaps of the image generator 2 and other components of the screen are reduced or even completely prevented.

[0105] In the following, with reference to Fig. 9, a second embodiment of a screen with an image generator 2 is described, which is divided into a first grid Ra with pixels Pßiid, in particular e.g. pixels Pßiid arranged in rows and columns, for displaying image content, and further comprising a second switchable light filter 5a. The second switchable light filter 5a in turn comprises: a second optical element 1a, which i. comprises a plurality of light-absorbing transition dipole moments which are in the form of molecules of one and / or in the form of one or more dichroic dyes, ii. wherein the majority of the transition dipole moments are aligned at least in a first state with a tolerance of maximum 20° parallel to a first preferred direction selectable for the second optical element 1a or vary around this, iii.so that light which is incident on the second optical element 1a is transmitted or at least partially absorbed depending on its polarization state and its direction of incidence relative to the second optical element 1a. iv. wherein the transition dipole moments are embedded in a liquid crystal layer 3a, so that the transition dipole moments can be varied in their orientation and / or their magnitude between the first and at least one second state in order to be able to alternatively place the second optical element 1a into at least two different states, Means 4 for selectively generating at least a first electric field EF1 or a second electric field EF2, which are divided into a second grid Rb of pixels PLC (this second grid is preferably, but not necessarily, structured in rows and columns);however, it could also be just rows or just columns), the transmission properties of the second switchable light filter 5a differ between a first operating mode B1 at corresponding pixels PLC, at which the first electric field EF1 is applied to the liquid crystal layer 3a, and a second operating mode B2 at corresponding pixels PLC, at which the second electric field EF2 is applied to the liquid crystal layer 3a, wherein explicitly either the first or the second electric field or another electric field can be applied to all pixels PLC, which typically assumes a numerical value between the numerical values ​​of the first and second electric fields EF1 and EF2; - wherein the first and the second grid Ra, Rb differ in at least one of the parameters - preferably in at least two of the parameters, alternatively in at least three of the parameters - resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes of the grids, alignment of the coordinate axes, in particular implementable e.g. in two 90° grids which are rotated relative to each other, and / or number of the respective pixels PLC or Pßiid, and - wherein, upon parallel projection of the second raster Rb onto the first raster Ra along the perpendicular bisector M onto the first raster Ra, less than 50% of the edges of pixels PLC of the second raster Rb are projected onto any edge of pixels Pßiid of the first raster Ra, thereby reducing visually visible overlaps of the image generator 2 and other components of the screen.

[0106] The transition dipole moments can—as described above—be formed by one or more dichroic dyes, i.e., by such dye molecules, which are integrated into the liquid crystals of the liquid crystal layer in a guest-host arrangement. In the second embodiment, the dye molecules then align themselves parallel to the liquid crystal molecules of the liquid crystal layer. The alignment of the liquid crystal molecules in the voltage-free electric field is, in turn, induced by the surfaces that bound them.

[0107] The first and second ITO layers ITO1, ITO2 here form the means 4 for selectively generating at least one first electric field EF1 or one second electric field EF2 pixel by pixel. They are coupled to control electronics (not shown in the drawing) that generate defined voltages. It is possible, for example, for either a first electric field EF1 or a second electric field EF2 to describe a field-free state, with the other (usually dynamic) electric field having an absolute field strength greater than zero, e.g., 0.5 MV / m.

[0108] Further layers and components not shown in Fig. 9 may be present, such as protective or cover layers made of glass and / or polymers. Such an exemplary screen according to Fig. 9 functions as described above. Due to the measures taken, namely that the first and second grids Ra, Rb differ in at least one of the parameters - preferably in at least two of the parameters, alternatively in at least three of the parameters - resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes of the grids, alignment of the coordinate axes (implementable, for example, in two 90° grids that are rotated relative to each other) and / or number of the respective pixels PLC or P B iid, visually visible overlaps of the image generator 2 and other components of the screen are reduced or even completely prevented.

[0109] The at least one dye consists of dye molecules, wherein each dye molecule is advantageously associated with a transition dipole or transition dipole moment, i.e., each dye molecule corresponds to a transition dipole or transition dipole moment. Typically, a dye has a mass fraction of 0.01% to 10% (or possibly significantly more), preferably 0.1% to 5%, of the material of the respective layer(s) in the first or second optical element. The thickness of the The thickness of the layers is preferably in the range from 0.2 pm to 50 pm, more preferably in the range from 0.5 pm to 20 pm, including all boundary values. The dyes or dye mixtures in the first and second optical elements can also be formed differently in their different layers, if present.

[0110] In general, this can be described as liquid crystal polymers doped with dye(s). Various approaches are known in the art (e.g., thermosettling LCs and epoxy LCs), which have already been mentioned above as examples and are not exhaustive. The preferred embodiment in the second embodiment is a mixture of liquid crystals with at least one dye, particularly with at least one dichroic dye mixture, for each layer.

[0111] Figure 10 shows, by way of example, how in the first optical element 1 the majority of the dipole moments DP1 are aligned within 20° of a selectable first preferred direction, here, for example, to the bisector, synonymous with vertical, and shown as a vertical dash-dot line (as an example, a=0° (alpha = 0°); here this is merely shown greater than 0° to make it easier to see). The majority of the transition dipole moments DP1 are shown in this state. Furthermore, some transition dipole moments DP2, i.e. the minority of the total of dipole moments DP1 and DP2, are shown with an alignment that exceeds the tolerance of 20°. Analogously, a representation could also be shown with a tolerance of 5° for the alignment of the transition dipole moments DP1 and outside the tolerance of 5°.

[0112] The mode of operation of the measures according to the invention in the first and second exemplary embodiments is explained in more detail below with the aid of Fig. 7a: Due to the fact that the first and second rasters Ra, Rb differ in several of the aforementioned parameters, in this case in the parameters resolution, pixel shape, pixel size, raster shape, base angle of the coordinate axes R1, R2 of the rasters Ra, Rb and number of the respective pixels PLC or Pßiid, in particular overlaps of local or overall area periods of the first and second rasters Ra, Rb are reduced or completely prevented. In this way, periodic brightness fluctuations are suppressed. In particular, visually visible overlaps of the image generator 2 and other components in the screen are thus reduced or even completely suppressed. The invention therefore helps to avoid moiré effects.

[0113] Both the first and the second embodiment of a screen in question can further be implemented such that the number of pixels PLC of the second raster Rb is smaller than the number of pixels P B iid of the first grid Ra. This property is also implemented in the example shown in Fig. 7a. This circumstance helps avoid visually visible overlaps between the two grids Ra and Rb, because this usually results in different periods of the grids Ra and Rb, and the period of the second grid Rb is also usually not an integer multiple of the first grid Ra.

[0114] Furthermore, in the example shown in Fig. 7a, the first and second grids Ra, Rb also differ in the base angle of the coordinate axes R1, R2, since in the second grid Rb, the coordinate axes R2 form an angle of approximately 75° to each other, while the coordinate axes R1 of the first grid Ra form an angle of approximately 90° to each other. This defined rotation also helps to suppress visually visible overlaps between the two grids Ra, Rb.

[0115] Furthermore, it may be advantageous if - as indicated in Fig.7a - the pixels PLC of the second grid Rb are designed in parallelogram form.

[0116] The Pixel P B iid of the first raster Ra can be designed in all embodiments, for example, as monochrome or as color subpixels (e.g. RGB or RGB-white).

[0117] In the example according to Fig.7a it is also realized that in parallel projection of the second grid Rb onto the first grid Ra along the perpendicular bisector to the first grid Ra less than 50% of the edges of pixels PLC of the second grid Rb onto any edge of pixels P B iid of the first raster Ra. This geometric condition also helps to avoid moiré effects and other visually visible overlays.

[0118] The said first preferred direction can advantageously enclose an angle between 0° and 45° inclusive to a surface normal of the first 1 or second optical 1a element. Furthermore, in special embodiments, the first preferred direction can vary across the surface of the first or second optical element 1, 1a, ie the respective preferred direction of a transition dipole moment is dependent on its position on the respective optical element 1, 1a can be selected. For the purposes of the invention, the first preferred direction averaged over the surface then applies.

[0119] In this context, it can be particularly useful for each first or second optical element 1, 1a to be divided into different regions (A1, A2, ...) along a selectable reference line on the respective first or second optical element, wherein a separate region-preferred direction can be selected for each region (A1, A2, ...), which applies to all transition dipole moments of the corresponding first or second optical element 1, 1a lying within a region (A1, A2, ...), wherein all region-preferred directions are different in pairs and point in the direction of an observer up to a tolerance of maximum + / -10 degrees. Within an optical element 1, 1a and within each region applicable thereto, all transition dipole moments are therefore within a tolerance of maximum + / -10 0each aligned parallel to the preferred direction applicable there.

[0120] Furthermore, it is possible for the means for selectively generating at least one first electric field EF1 or one second electric field EF2 to also selectively generate third, fourth or further electric fields different therefrom at pixels PLC of the second grid Rb, so that third, fourth and optionally further states can be generated for the liquid crystal layer 3, 3a, which then in turn cause third, fourth and optionally further absorption or transmission characteristics of the (first or second) switchable light filter 5, 5a at locations of the pixels PLC of the second grid Rb in previously described screens.

[0121] Advantageously, the image sensor 2 corresponds to an LCD panel, one of whose polarization filters corresponds to the optional polarization filter P in the screen. This can be the front or rear polarizer in the LCD structure.

[0122] The imager 2 can alternatively be an OLED, a SED screen, a field emission display (FED), a microLED panel, or a vacuum fluorescent display (VFD), in front of which a first or second switchable light filter 5, 5a is arranged. Since the described first and second switchable light filters 5, 5a of the screen are effective regardless of the type of imager 2, any other screen types are also possible.

[0123] The invention described above solves the problem: A screen with a switchable light filter has been described. The switchable light filter is It is inexpensive to implement and, in particular, universally applicable to various screen types, enabling switching between a privacy mode, i.e., a restricted viewing mode, and a free viewing mode, without reducing the resolution of such a screen. This achieves good image quality, particularly with no or imperceptible moiré effects between the screen's image sensor and the switchable light filter.

[0124] The invention described above can be advantageously applied wherever confidential data is displayed and / or entered, such as when entering a PIN or displaying data at ATMs or payment terminals, when entering passwords, or when reading emails on mobile devices. As described above, the invention can also be used in cars to selectively withhold distracting image content from the driver or passenger.

[0125] List of reference symbols 1 first optical element 1a second optical element 2 imagers 3 Liquid crystal layer 3a Liquid crystal layer 4 means ITO1 ITO layer ITO2 ITO layer P Linear Polarizing Filter Pßiid pixels in the first grid PLC pixels in the second grid R1 Coordinate axes first grid R2 coordinate axis second grid Ra first grid Rb second grid DP transition dipole moments DP1 Majority of transition dipole moments with maximum tolerance DP2 Minority of transition dipole moments outside the tolerance M bisector synonymous with perpendicular

Claims

Patent claims 1 . Screen with an image generator (2) which has a first grid (Ra) with pixels P for displaying image content B iid, further comprising a first switchable light filter (5), in turn comprising - a first optical element (1), - means (4) for selectively generating at least a first electric field (EF1) or a second electric field (EF2) divided into a second grid of pixels PLC, - a liquid crystal layer (3) arranged in front of or behind the first optical element (1), on which the electric field generated at the pixels PLC acts and which, depending thereon, influences the polarization state of light passing through it, so that - the transmission properties of the switchable light filter (5) differ between a first operating mode B1 at corresponding pixels PLC to which the first electric field (EF1) is applied, and a second operating mode B2 at corresponding pixels PLC to which the second electric field (EF2) is applied, - wherein the first and the second grid (Ra, Rb) differ in at least one of the parameters resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes (R1, R2) of the two grids (Ra, Rb), orientation of the coordinate axes (R1, R2) and / or number of the respective pixels PLC or P B iid distinguish, and - wherein, upon parallel projection of the second raster (Rb) onto the first raster (Ra) along the perpendicular bisector to the first raster (Ra), less than 50% of the edges of pixels PLC of the second raster (Rb) are projected onto any edge of pixels Pßiid of the first raster (Ra), thereby reducing visually visible overlaps of the image generator (2) and other components of the screen.

2. Screen with an image generator (2), in particular according to claim 1, which has a first grid (Ra) with pixels Pßiid for displaying image contents, further comprising a first switchable light filter (5), in turn comprising - a first optical element (1), in turn comprising • a variety of light-absorbing transition dipole moments (DP1, DP2), • wherein the majority (DP1) of the transition dipole moments are permanently or at least in a first state with a tolerance of a maximum of 20° parallel to a first preferred direction selectable for the first optical element (1) or vary around this, • so that light incident on the first optical element (1) is transmitted or at least partially absorbed depending on its polarization state and its direction of incidence relative to the first optical element (1), - means (4) for selectively generating at least a first electric field (EF1) or a second electric field (EF2) divided into a second grid of pixels PLC, - a liquid crystal layer (3) arranged in front of or behind the first optical element (1), on which the electric field generated at the pixels PLC acts and which, depending thereon, influences the polarization state of light passing through it, so that - wherein the transmission properties of the switchable light filter (5) differ between a first operating mode B1 at corresponding pixels PLC to which the first electric field (EF1) is applied, and a second operating mode B2 at corresponding pixels PLC to which the second electric field (EF2) is applied, - wherein the first and the second grid (Ra, Rb) differ in at least one of the parameters resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes (R1, R2) of the two grids (Ra, Rb), orientation of the coordinate axes (R1, R2) and / or number of the respective pixels PLC or P B iid distinguish, and - wherein, upon parallel projection of the second raster (Rb) onto the first raster (Ra) along the perpendicular bisector to the first raster (Ra), less than 50% of the edges of pixels PLC of the second raster (Rb) are projected onto any edge of pixels Pßiid of the first raster (Ra), thereby reducing visually visible overlaps of the image generator (2) and other components of the screen.

3. Screen with an image generator (2) which, for displaying image content, is divided into a first grid (Ra) with pixels P B iid, further comprising a second switchable light filter (5a), in turn comprising a second optical element (1a), which • a plurality of light-absorbing transition dipole moments (DP1, DP2) which are formed in the form of molecules of one and / or in the form of one or more dichroic dyes, • wherein the majority (DP1) of the transition dipole moments are aligned at least in a first state with a tolerance of a maximum of 20° parallel to a first preferred direction selectable for the second optical element (1a) or vary around this, • so that light which is incident on the second optical element (1a) is transmitted or at least partially absorbed depending on its polarization state and its direction of incidence relative to the second optical element (1a), • wherein the transition dipole moments are embedded in a liquid crystal layer (3a), so that the transition dipole moments can be varied in their orientation and / or their amount between the first and at least one second state in order to be able to alternatively place the second optical element (1a) into at least two different states, Means (4) for selectively generating at least one first electric field (EF1) or one second electric field (EF2), which are divided into a second grid (Rb) with pixels PLC, wherein the transmission properties of the second switchable light filter (5a) differ between a first operating mode B1 at corresponding pixels PLC, at which the first electric field (EF1) is applied to the liquid crystal layer (3a), and a second operating mode B2 at corresponding pixels PLC, at which the second electric field (EF2) is applied to the liquid crystal layer (3a), wherein the first and the second grid (Ra, Rb) differ in at least one of the parameters resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes (R1, R2) of the two grids, alignment of the Coordinate axes (R1, R2) and / or number of respective pixels PLC or P Biid, and wherein, in parallel projection of the second grid (Rb) onto the first grid (Ra) along the perpendicular bisector to the first grid (Ra), less than 50% of the Edges of pixels PLC of the second raster (Rb) are projected onto any edge of pixels Pßiid of the first raster (Ra), thereby reducing visually visible overlaps of the imager (2) and other components of the screen.

4. Screen according to one of claims 1 to 3, characterized in that at corresponding pixels PLC to which the first electric field (EF1) is applied, in a first operating mode B1, on the one hand, linearly or elliptically polarized light which is incident parallel to the first preferred direction into the first or second switchable light filter (5, 5a) is transmitted to at least 24%, and on the other hand, linearly or elliptically polarized light which is incident at least at a first angle of more than 35° to the first preferred direction, which lies in a first plane, into the first or second switchable light filter (5, 5a) is absorbed to at least 85%, at corresponding pixels PLC to which the second electric field (EF1) is applied, in a second operating mode B2, on the one hand, linearly or elliptically polarized light which is incident parallel to the first preferred direction into the first or second switchable light filter (5, 5a),at least 24% is transmitted and, on the other hand, linearly or elliptically polarized light which is incident on the first or second switchable light filter (5, 5a) at at least a second angle of more than 35° to the first preferred direction, which lies in a second plane, is absorbed to at least 85%, wherein the first and second planes intersect at an angle of 80° to 100°, so that the directions of absorption for the first operating mode B1 and the second operating mode B2 differ by 80° to 100°, respectively.

5. Screen according to one of the preceding claims, characterized in that the number of pixels PLC of the second raster (Rb) is smaller than the number of pixels Pßiid of the first raster (Ra).

6. Screen according to one of the preceding claims, characterized in that the first and the second grid (Ra, Rb) differ at least in their base angle of the coordinate axes (R1, R2), in that in the second grid (Rb) the coordinate axes have an angle between 45° and less than 88° to one another, while the coordinate axes of the first grid (Ra) have an angle between 88° and 92° to one another.

7. Screen according to one of the preceding claims, characterized in that the pixels P B iid of the first grid (Ra) is rectangular and the pixels PLC of the second (Rb) grid are non-square, preferably parallelogram-shaped.

8. Screen according to one of the preceding claims, characterized in that at least two pixels PLC of the second raster (Rb) have a different size and / or shape from one another.

9. Screen according to one of the preceding claims, characterized in that the pixels P B iid of the first raster (Ra) are formed as color subpixels.

10. Screen according to one of the preceding claims, characterized in that in parallel projection of the second grid (Rb) onto the first grid (Ra) along the perpendicular bisector to the first grid (Ra), less than 20%, preferably less than 5%, of the edges of pixels PLC of the second grid (Rb) onto any edge of pixels P B iid of the first grid (Ra).

11. Screen according to one of the preceding claims, characterized in that the means (4) for selectively generating at least a first electric field (EF1) or a second electric field (EF2) can selectively also generate third, fourth or further electric fields different therefrom at pixels PLC of the second raster (Rb).

12. Screen according to claim 1 with an image generator (2) which has a first grid (Ra) with pixels P for displaying image contents B iid, further comprising a first switchable light filter (5), in turn comprising - as the first optical element (1), a linear polarization filter which transmits or at least partially absorbs light depending on its polarization state and / or its direction of incidence, wherein the polarization direction with maximum transmission can be selected for the linear polarization filter, - means (4) for selectively generating at least a first electric field (EF1) or a second electric field (EF2), which are divided into a second grid (Rb) with pixels PLC, - a liquid crystal layer (3) arranged in front of or behind the linear polarization filter, onto which the light generated at the pixels PLC electric field, which, depending on this, influences the polarization state of light passing through it, so that - the transmission properties of the switchable light filter (5) differ between a first operating mode B1 at corresponding pixels PLC to which the first electric field (EF1) is applied, and a second operating mode B2 at corresponding pixels PLC to which the second electric field (EF2) is applied, - wherein the first and second grids (Ra, Rb) are located in at least one of the Parameters resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes (R1, R2) of both grids, alignment of the Coordinate axes (R1, R2) and / or number of respective pixels PLC or P B iid distinguish, and - wherein, upon parallel projection of the second raster (Rb) onto the first raster (Ra) along the perpendicular bisector to the first raster (Ra), less than 50% of the edges of pixels PLC of the second raster (Rb) are projected onto any edge of pixels Pßiid of the first raster (Ra), thereby reducing visually visible overlaps of the image generator (2) and other components of the screen.

13. Screen, in particular as an intermediate product of a screen according to claim 1, with an image generator (2) which has a first grid (Ra) with pixels Pßiid for displaying image contents, further comprising Means (4) for selectively generating at least one first electric field (EF1) or one second electric field (EF2), which are divided into a second grid (Rb) with pixels PLC, a liquid crystal layer (3) arranged on or between the means (4) for selectively generating at least one first electric field (EF1) or one second electric field (EF2), on which liquid crystal layer the electric field generated at the pixels PLC acts and which, depending thereon, influences the polarization state of light passing through it, wherein the first and the second grid (Ra, Rb) differ in at least one of the parameters resolution, pixel shape, pixel size, grid shape, base angle of the coordinate axes (R1, R2) of the two grids, orientation of the Coordinate axes (R1, R2) and / or number of respective pixels PLC or Pßiid differ, and wherein, upon parallel projection of the second raster (Rb) onto the first raster (Ra) along the perpendicular bisector to the first raster (Ra), less than 50% of the edges of pixels PLC of the second raster (Rb) are projected onto any edge of pixels Pßiid of the first raster (Ra), thereby reducing visually visible overlaps of the image generator (2) and other components of the screen.

14. Use of a screen according to claim 13 with a first optical element (1), itself comprising i. a plurality of light-absorbing transition dipole moments (DP1, DP2), ii. wherein the majority (DP1) of the transition dipole moments are permanently or at least in a first state with a tolerance of a maximum of 20° aligned parallel to a first preferential direction selectable for the first optical element (1) or vary around this, iii.such that light which is incident on the first optical element (1) is transmitted or at least partially absorbed depending on its polarization state and on its direction of incidence relative to the first optical element (1), such that the polarization properties of the light incident on the first optical element (1) from the imager differ between a first operating mode B1 at corresponding pixels PLC to which the first electric field (EF1) is applied, and a second operating mode B2 at corresponding pixels PLC to which the second electric field (EF2) is applied.

Images