WO2017140880A1

WO2017140880A1 - Autostereoscopic screen and use thereof to reproduce three-dimensionally perceptible images

Info

Publication number: WO2017140880A1
Application number: PCT/EP2017/053675
Authority: WO
Inventors: René DE LA BARRÉ; Silvio Jurk; Mathias Kuhlmey
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2016-02-17
Filing date: 2017-02-17
Publication date: 2017-08-24
Also published as: DE102016202431A1

Abstract

The invention relates to an autostereoscopic screen for reproducing at least two different images, each visible from one of a corresponding number of laterally offset observation zones (25, 25'), comprising a pixel matrix (21), which has a plurality of pixels of at least three different basic colors, which pixels are arranged in rows, and comprising an optical barrier (22), which is arranged in front of or behind the pixel matrix (21) and which is designed to apply a defined propagation direction to light emanating from the pixels or transmitted by the pixels and to conduct said light into one of the different observation zones (25, 25'), wherein the optical barrier (22) has filter elements for this purpose, each of which is transparent for light of exactly one of the basic colors at least in one possible state, and wherein each row of the pixel matrix (21) is formed by pixels of the same basic color. The invention further relates to a use of said screen to reproduce autostereoscopically three-dimensionally perceptible images.

Description

Autostereoscopic screen and its use for reproducing three-dimensionally perceptible images

The invention relates to an autostereoscopic screen for reproducing a number of at least two different images, each of which is visible from one of an equal number of laterally offset viewing zones in front of the screen, according to the preamble of the main claim. Moreover, the invention relates to a use of such a screen for reproducing autostereoscopic three-dimensionally perceptible images.

A generic screen comprises a pixel matrix having a plurality of pixels arranged in a plurality of rows of at least three different primary colors, and an optical barrier arranged in front of or behind the pixel matrix, which is arranged to emit light emitted by the pixels or transmitted by the pixels to impose a defined propagation direction and to introduce this light into one of the various For this purpose, the optical barrier has filter elements that are transparent to light of exactly one of the primary colors, at least in one possible state. As a result, a generic screen is suitable for simultaneously reproducing two or more different images, which are visible from one of a corresponding number of laterally offset viewing zones in front of the screen.

Such screens are e.g. known from the document DE 100 03 326 C2. A disadvantage of the prior art known screens of this type is that even a slight lateral movement of a viewer of the

Screen results in a significant decrease in the perceived image brightness, because shading of the pixels by linear at least for light of the corresponding wavelength opaque elements of the optical barrier with the lateral movement increases linearly, thus linearly decreases a luminance or luminance of the screen as the lateral movement progresses.

The invention is therefore based on the object to develop an autostereoscopic screen with which the highest possible image resolution can achieve the highest possible image brightness, in such a way that the image brightness remains as unimpaired even with a lateral movement of a viewer of the screen, the Screen at the same time as possible to make possible a good separation between different images that should be visible from different viewing zones, so that a crosstalk between these images is thus avoided as well as possible.

This object is achieved by an autostereoscopic screen with the features of the main claim and by use of such a screen according to claim 10. Advantageous embodiments and further developments of the invention will become apparent with the features of the dependent claims.

Through the use of wavelength-selective filter elements for the optical barrier provided for the separation of the different images, a crosstalk between the images, ie a partial visibility of one of the images from one of the viewing zones, which corresponds to another of the image which is associated relatively well prevented, without sacrificing image brightness and / or image resolution. This is interesting considering that a conventional way to better image separation would be to change the screen geometry at the expense of image brightness and / or image resolution. So are conventional autostereoscopic

Screens with other parallax barriers are characterized by a high loss of light, because crosstalk in these screens can be reduced or reduced only by reducing or reducing the number of barrier openings, which reduces the display brightness. By contrast, the filter elements, which are transparent to light of one and only one of the primary colors at least in one possible state, already contribute to the separation of the images because of this wavelength selectivity. Thus, light that emanates from a pixel of a certain base color and falls on one of the filter elements or that - in the case of an arrangement of the optical barrier behind the pixel matrix - falls from one of the filter elements on a pixel of a certain primary color, only in one through the position of the pixel and the filter element predetermined viewing zone fall when the filter element is transparent to light exactly this basic color. If a pixel of another primary color is then controlled in accordance with image information of another image, crosstalk can therefore be excluded even if this pixel is in the immediate vicinity of that pixel mentioned above. Typically, the base colors will be selected as red, green and blue, but other primary colors or a larger number of base colors may be chosen that are capable of superimposing all desired image colors.

The invention now provides that the rows of the pixel matrix are each formed by pixels of a base color which is the same for all pixels of the respective row. This has the following advantageous effect. If a pixel from one of the lines previously visible to a viewer by a particular filter element or, in the case of an optical barrier array behind the pixel matrix, from a particular filter element, would move a viewer through one for light of the base color As this opaque part of the optical barrier becomes increasingly obscured or shadowed, an adjacent pixel from the same line becomes more or less visible due to its same primary color in front of or behind the same filter element, namely from the viewer's perspective at the same point on the screen. Because of the spatial proximity of the two pixels, these will generally also be controlled with at least very similar brightness values, so that the lateral movement, despite the changing occlusion or shading of the individual pixels, has no noticeable influence on the image brightness perceived by the viewer. As a result, the invention overcomes the problem of a significant drop in the perceived image brightness even with slight lateral movements of the observer. In order to distribute the pixels of each of the primary colors as evenly as possible over the pixel matrix and thereby enable a color-true reproduction of images with the best possible quality, the pixels can be arranged so that the basic colors of the pixels of the successive lines from top to bottom in alternate cyclic order.

As mentioned, the optical barrier can be arranged in front of or behind the pixel matrix. The pixels can therefore be arranged between the optical barrier and an illumination of the pixel matrix, but an arrangement is also conceivable in which the optical barrier is placed between a background illumination and the pixel matrix. Even though the following description limits the typical variant of an optical barrier arranged in front of the pixel matrix in some places, the other alternative of an optical barrier arranged behind it can likewise be realized just as well. That and how both arrangements can analogously achieve the reproduction and separation of different images results, e.g. from the previously mentioned document DE 100 03 326 C2, the content of which is referenced insofar, there in particular from a comparison of the embodiments of Figure 10 on the one hand with the embodiments of Figures 1 and 8 on the other.

Both with regard to a simple production of the screen and with respect to the possibility of using comparatively simple schemes for writing image information of the various images into the pixel matrix, it may be favorable if the filter elements of the optical barrier are arranged such that the Filter elements of each of the primary colors a pattern of vertical or approximately vertical and / or in form stripes of columns of the pixel matrix. This avoids the need to place the observer with his eyes at a certain height in front of the screen or to adjust a control of the screen to the height of the observer's eyes. Constructively particularly simple solutions provide that the pixels of the different lines form vertical and perpendicular to the rows running columns. However, it is also possible to provide a slope of columns of the pixel matrix which is inclined with respect to the vertical. Also, the strips of filter elements of the same basic color may, in some circumstances, extend in a direction inclined by up to about 20 ° relative to the vertical, instead of in the exact vertical direction. In order to avoid the formation of disturbing moiré patterns, it may be helpful to avoid an exactly parallel progression of columns of the pixel matrix and stripes of the optical raster in that the columns of the pixel matrix and / or the stripes of the optical raster have one of Straight lines have a different course. For example, the columns or stripes may be wavy or zigzag-shaped.

The filter elements may e.g. be arranged so that the basic colors of the filter elements of the successive strips alternate from left to right in cyclic order. However, other periodic arrangements of the colors of the successive strips are also conceivable.

An expedient method results from using a screen of the type described here for reproducing autostereoscopic three-dimensionally perceivable images, in which the pixels of the pixel matrix are driven in response to image data of a number of different views of a scene corresponding to the number of viewing zones Views on a subset of the pixels is displayed and each of the viewing zones is visible, the views differ so that they complement each other in pairs to a stereo image of the scene. In each case one of these viewing zones is exactly one or - apart from possible crosstalk effects by overlapping the viewing zones - at least in the first line one of these views visible. For example, a viewer placed in front of the screen may have their eyes in two different viewing zones

Autostereoscopic scene with depth effect perceive. For this purpose, the screen can have a control unit for driving the pixel matrix, which is set up to control the pixels of the pixel matrix in such a way depending on image data of a number of viewing zones corresponding to the number of viewing zones that each of these images is reproduced on a subset of the pixels and is visible from each one of the different viewing zones, wherein typically from each of the viewing zones exactly one or at least primarily one of these images is visible.

Embodiments are conceivable in which exactly two complementary images or views for viewing from two viewing zones are reproduced if the screen is to be designed for use by a single viewer, ie as a so-called single-user display. But also possible versions in which a larger number of images or

Views and is visible from a correspondingly larger number of viewing zones. Then, the screen forms a so-called multi-view display, which may be suitable for autostereoscopic viewing by several observers and in which a single viewer each dependent on his current position and changing with a movement of the viewer perspective of the reproduced scene will see.

In addition, measures for a so-called tracking can be provided, ie a detection of eye positions or a head position of a viewer and a definition of said subsets and driving the pixel matrix depending on the detected eye positions or the detected head position such that the viewer at least the reproduced scene within relatively wide limits regardless of its exact position with depth effect can see. The screen may additionally comprise a device for detecting eye positions or a head position of a viewer, the control unit then being set up to control the pixel matrix depending on the detected eye positions or the detected head position. This is expedient in particular if the screen is a single-user display in the sense described above.

Also, some of the pixels, each partially composed of two viewing zones, NEN are visible, two of the subsets are assigned and controlled with an intensity value, which results from an averaging depending on image information of two of the images. This can be helpful for achieving a good image quality, in particular if the image data or image information is to be moved laterally or stretched or compressed in the pixel matrix in order to control the pixel matrix to a lateral movement of the viewer or to a smaller or to adjust to a larger viewing distance. How this can be done in a manner that can also be used for the screen described here is shown in document WO 2013/110779 A1 using the example of a conventional one

Multi-view displays.

It can be provided that the filter elements can each be switched between a state which is transparent to light of precisely one of the primary colors and an opaque state. For this purpose, the optical barrier may e.g. be formed by a liquid crystal display, which in turn may be provided with wavelength-selective filters. Apart from ordinary LC cells with color filters, fast switchable LC filters such as Fabry-Perot cells or Lyot filter layers are also suitable for the switchable filter elements. Alternatively, the switchable filter elements can also be produced with mechanically tunable elements in the form of so-called MEMS, such as e.g. in US 2006/0139723 A9, US 6,710,908 B2 and US 8,068,269 B2. When the filter elements of each of the primary colors, as described above, respectively form a pattern of strips extending in the direction of the columns, each of the strips may be formed by a plurality of switchable filter elements, for example in a matrix-like arrangement of the filter elements. However, a particularly simple structure and a comparatively simple electrical control results when, in this case, each of the strips is formed by a single filter element which is desensprechend strip-shaped.

If the filter elements are switchable in the manner described, the control unit may be set up to control not only the pixel matrix but also the optical barrier and switch the optical barrier alternately between at least two different switching states, wherein the switching states differ from each other in that the filter elements differ grouped are grouped into groups of opaque Filter elements and groups of transparent for light of the respective base color filter elements. It is particularly expedient if the different switching states differ from one another such that different regions of the pixel matrix are visible from each of the viewing zones in the different switching states through the filter elements connected transparently or in front of the filter elements connected transparently, while different regions in each case are visible Viewing from this viewing zone are covered or shaded by opaque filter elements, which are then visible from another of the viewing zones.

In this way, the image brightness and image resolution perceived by a viewer can be significantly improved because - given a pixel matrix - a total of more pixels are available for displaying each of the displayed images, and if viewed from each of the viewing zones then fewer regions of the pixel matrix become permanent appear dark. For this purpose, it is expedient if the control unit is also set up to change an activation of the pixel matrix at or after each switching between different switching states of the optical barrier by redistributing the pixels to the subsets so that each of the images becomes visible after switching from the same viewing zone is like before switching.

A correspondingly advantageous embodiment of the described use of the screen accordingly provides that the optical barrier is alternately switched between at least two different switching states, the switching states differing from one another in that the filter elements are grouped differently into groups of opaque filter elements and groups of Light the respective base color transparent filter elements, so that each of the

Viewing zones in the different switching states each different areas of the pixel matrix through the transparent filter elements are visible, while each different areas are covered or shaded when viewed from this viewing zone by opaque filter elements, which are then visible from another of the viewing zones, an activation of the pixel matrix or after each switching between different switching states of the optical barrier by redistributing the pixels to the subsets so that each of the views is visible after switching the optical barrier out of the same viewing zone as before the switching.

In the manner described, not only spatial but also temporal multiplexing of the various reproduced images or views can be achieved, which benefits the spatial resolution of the images. The switching between the switching states of the optical barrier is of course preferably done sufficiently fast to be imperceptible to a viewer.

The individual pictures can each be time-dependent. Identity of the images that are visible before or after switching from one or the other viewing zone does not necessarily mean here that the respective image is unchanged, but under certain circumstances only that it is assigned to the same view, if - what the most typical case is - the images are each different views of the same scene and the views differ from one another by slightly different viewing angles or parallaxes, so that they complement each other in a stereo image that can be perceived in three dimensions, while the scene itself can of course be time-dependent, eg when playing a movie.

With regard to the best possible image resolution and image brightness, it may be advantageous if, during the reproduction of the images, a number of different switching states of the optical barrier lying between two and the mentioned number of views is switched through, so that as complete as possible utilization of the pixel matrix for the generation of each each of the pictures can be achieved. The mentioned control unit can accordingly be set up to switch through a number of different switching states of the optical barrier lying between two and the mentioned number of viewing zones.

The pixel matrix may be, for example, a standard colored LC display. However, other embodiments of the pixel matrix are also possible, for example those in which the pixels are replaced by MEMS or other mechanically tunable elements be generated, for example, in the US 2008/0080032 AI type shown.

In embodiments of the screen with switchable filter elements, it may be provided that the pixel matrix for column-by-column writing of

Image information is set up and that the optical barrier is arranged for strip-wise driving of the filter elements, wherein "stripwise" refers to extending in the direction of the columns strip in which the filter elements are arranged or which are formed by the filter elements, each of the strips e.g. may be formed by a single filter element or by a plurality of filter elements of the same basic color. This makes it possible to coordinate the switching of the optical barrier and the change of the control of the pixel matrix particularly well in time and thereby to minimize dark phases, because the changed writing of image information can be started before the switching of the optical barrier is completed. The pixel matrix may be e.g. a normal display rotated by 90 °. Depending on the design of the optical barrier, the front and rear sides of the pixel matrix may also need to be reversed by a further rotation so that possibly provided polarizing components in pixel matrix and optical barrier are suitably oriented relative to one another.

Accordingly, in order to minimize dark phases and thereby largely avoid losses in the image brightness, the described use of the screen can be configured so that the image information or image data of the different views are written into the pixel matrix in columns, the optical barrier extending in the column direction Strip each having one or more filter elements, which may be formed in the latter case of filter elements of a same color for all filter elements of a strip base color, and wherein the switching states of the filter elements of the optical barrier are changed in strips each strip. The writing of the image information takes place, for example progressing from left to right or from right to left, changing the switching states of the strips of filter elements, preferably progressing in the same direction. Embodiments of the invention are explained below with reference to FIGS 1 to 13. It shows

1 is a schematic representation of a plan view of an autostereoscopic screen with a pixel matrix and an optical barrier and a viewer's space in front of this screen,

2 shows, in a corresponding illustration, a modification of the autostereoscopic screen in which the pixel matrix and the optical barrier are arranged differently,

3 is a detail of the pixel matrix of the screen, which is shown in the figure above next to each other in two different driving states and below each again together with the optical barrier, the optical barrier occupies one of two different switching states,

4 in a representation corresponding to FIG. 3, the pixel matrix in the case of an embodiment of the screen as a multi-person screen or MultiView display, FIG.

5 shows a corresponding representation of the pixel matrix in a modification of the embodiment from FIG. 4, FIG.

6 in a corresponding representation of the pixel matrix in a modification of the embodiment from FIG. 3, FIG.

7 shows a section of the pixel matrix of the screen in a further embodiment in which three switching states of the optical barrier and accordingly three activation states of the pixel matrix are switched through, wherein the section of the pixel matrix in the figure to the left among each other in the three different control states and right next to each once shown together with the optical barrier, 8 shows the detail of the pixel matrix on the left in the figure and on the right next to it again this detail together with the optical barrier in one of the switching states with a slightly modified activation of the pixel matrix,

9 shows a detail of the pixel matrix of the screen shown in the figure on the right in another embodiment and on the left next to it again this detail together with the optical barrier,

10 shows a pixel row of the pixel matrix in a further embodiment of the screen, together with a row of filter elements of the optical barrier arranged in front of it, FIG.

11 for a screen of the type shown in FIG. 1, a beam path illustrated horizontally for light emanating from pixels of the pixel matrix and falling into the viewer's space, FIG.

FIG. 12 shows a detail of a pixel row of the pixel matrix with an optical barrier disposed therebefore in an embodiment in which opaque areas remain between individual filter elements of the optical barrier, and FIG

FIG. 13 shows, in a representation corresponding to FIG. 11, a beam path for the light emanating from pixels of the pixel matrix and falling into the viewer's space in this embodiment of the optical barrier.

FIG. 1 shows an autostereoscopic screen which has a pixel matrix 21, an optical barrier 22 arranged in front of it and a backlight 23 arranged behind the pixel matrix 21 and a control unit 24 for driving both the pixel matrix 21 and the optical barrier 22. This screen is set up to simultaneously display a number of two or even more than two different images, which are visible from a viewer's space in front of the screen, such that each of these images from each one of correspondingly many viewing zones 25 shown here in a rhombus. 25 and 25 'can be seen. The screen can be designed as a so-called single-user display or as a so-called multi-view display. In the first case, it is set up for the simultaneous reproduction of exactly two different images, which are visible from the two viewing zones 25. If the screen is a multi-view display, there may be a larger number of different ones

Images are reproduced simultaneously, two of which are visible from the two central viewing zones 25 and the others from each of the laterally adjoining further viewing zones 25 '. When used as intended, the screen is controlled so that the various simultaneously displayed images of different views correspond to a scene that differ from each other so that they complement each other in pairs to form a stereo image of the scene. A viewer who is placed in the viewer's room so that his eyes are in two adjacent viewing zones 25 and 25 'can thereby perceive the reproduced scene autostereoscopically with depth effect. In the case of the multi-view display, the scene can thus be perceived in three dimensions simultaneously by several viewers placed next to each other. A lateral offset between immediately adjacent viewing zones 25 and 25 'can be used for this purpose, e.g. a typical eye distance corresponding to about 65 mm.

In addition, a tracking device 26 may be provided, e.g. can detect eye positions or a head position of a viewer with the help of two cameras, the control unit 24 in this case, depending on an output signal of the tracking device 26 to control so that the viewer the reproduced scene within very wide limits regardless of its exact position with depth effect able to see.

The pixel matrix 21, which is e.g. can act through a liquid crystal display or together with the backlight 23 can form a liquid crystal display, a plurality of pixels arranged in rows and columns each have one of the three primary colors red, green and blue. At this time, the rows of the pixel matrix 21 become one by one for each pixel

Pixels of this line have the same base color, so that the pixel matrix 21 has pixels of exclusively red primary color, lines of pixels exclusively of green primary color and lines of pixels exclusively of red primary color. In the following figures, the individual pixels or the rows of pixels, if recognizable, are each identified by one of the letters R, G or B, where R stands for a red pixel or a row of red pixels, G for a green pixel or a pixel Row of green pixels and B stands for a blue pixel or a row of blue pixels. In addition, the pixels in each of the following figures are each numbered between 1 and 18. This number then stands for the number of one of several views which are simultaneously displayed on the screen and which are numbered consecutively, whereby the number noted in a pixel always stands for the number of the view which the respective pixel contributes to the reproduction.

The optical barrier 22 has filter elements which are each switchable between an opaque state and a state which is transparent to light of exactly one of the primary colors red, green or blue, and are therefore particularly wavelength-selective. Diffusers may be placed in front of the filter elements to reduce the dependency of image quality on the exact viewer position. As a result of the arrangement and the wavelength selectivity of the various filter elements, the optical barrier 22 can impose a defined propagation direction on the light emitted by the pixels of the pixel matrix 21 and guide this light into one of the different viewing zones 25 and 25 '. The switchability of the filter elements may be e.g. be realized in that the optical barrier 22 is formed by a further liquid crystal display.

When the screen is used as intended, the control unit 24 set up accordingly controls the pixels of the pixel matrix 21 in such a way depending on image data of the different views that these views are displayed simultaneously on the pixel matrix 21, such that each of these views is displayed on one pixel Subset of the pixels is reproduced and from each one of the viewing zones 25 or 25 'is visible and that from each of the viewing zones 25 and 25' exactly one or at least in the first line - namely, apart from possible crosstalk between seeing views, the adjacent viewing zones 25th or 25 'are assigned - each one of these views is visible. If a tracking of the Observers is provided by the tracking device 26, the subsets can be defined depending on the detected eye positions or the detected head position. Also, some of the pixels, when at least partially visible from two of the viewing zones 25 and 25 'respectively, may be associated with two of the subsets and with one

Intensity value are controlled, which results from an averaging depending on image information of two of the images.

As mentioned, the filter elements of the optical barrier 22, which as the pixels of the pixel matrix 21 are shown as such only in later-described figures, can be switched, the control unit 24 not only for driving the pixel matrix 21 but also for driving the optical barrier 22 is set up. The control unit 24 is now arranged to switch the optical barrier 22 alternately between at least two different switching states, wherein the switching states differ from one another in that the filter elements are grouped differently into groups of opaque filter elements and groups of light respective basic color red, blue or green transparent filter elements, so that each of the viewing zones 25 and 25 and 25 'in the different switching states respectively different areas of the

Pixel matrix 21 are visible through the transparent filter elements switched, while each different areas are covered when viewed from this viewing zone 25 and 25 'through the opaque filter elements, which are then visible from another of the viewing zones 25 and 25 and 25'. In this case, the control of the pixel matrix 21 is changed at or after each switching between the different switching states of the optical barrier 22 by redistributing the pixels to the subsets such that each of the views after the switching of the optical barrier 22 from the same viewing zone 25 or 25 '. is visible as before switching. The switching happens of course so fast that it is no longer perceptible to the viewer.

2, an autostereoscopic screen is shown in a representation corresponding to FIG. 1, which differs from the above-described embodiment only in that the pixel matrix 21 and the optical barrier 22 are arranged differently. Repetitive or equivalent In this case and in the remaining figures, the same features are again provided with the same reference numerals. In this case, the optical barrier 22 is arranged not in front but behind the pixel matrix 21, between the pixel matrix 21 and the background illumination 23 placed further back here. This arrangement also permits a separation of the different ones on the pixel matrix 21 from each one of several subsets of pixels rendered views such that the different views from the different viewing zones 25 and 25 'are visible. In this case, the optical barrier 22 provided here with switchable wavelength-selective filter elements also imparts a defined direction of propagation to the light emanating from the backlight 23, initially passing through the optical barrier 22 and then transmitted by the pixels of the pixel matrix 21, because the light is only propagated through each such pairs of each of the filter elements and one of the pixels may fall into the viewer space, where the pixel has the same base color as the filter element. Therefore, different partial regions of the pixel matrix 21 in front of the respective transparent filter elements of the optical barrier 22 are visible from each of the viewing zones 25 or 25 ', which is also switched between different switching states, while different partial regions are observed when viewed from this viewing zone 25 or 25 'appear shaded by opaque filter elements, so that the pixels lying in these areas remain invisible.

FIG. 3 shows a section of the pixel matrix 21, in the figure above, twice next to one another in two different activation states and below each again in the same state behind the optical barrier 22 arranged in front of it, the optical barrier each one of two different ones Switching states occupies. Between these switching states, alternating switching takes place in rapid succession, whereby synchronization of the activation of the pixel matrix 21 between the two is synchronized

Control states is switched. Illustrated here is the control of the pixel matrix 21 and the optical barrier 22 in a case in which the screen is a single-user display and in which each of two subsets of pixels one of two views is played, one of a left and one from a right of two viewing zones 25 is visible and are accordingly provided for each one of two eyes of a pair of eyes to complement each other to a stereo image.

The pixels of the pixel matrix 21 are identified in FIG. 3 with 1 or 2 or with 1x2. On the pixels marked 1, a first of the two views is displayed, and on the pixels marked 2, a second of the two views is displayed. The pixels marked with 1x2 are controlled with brightness values, which result in each case by averaging a brightness value defined by the first view for the respective location in the image and a brightness value defined by the second view for the same location in the image. The same applies to the pixels, which are sometimes also identified by larger numbers in the following figures, which are then controlled in a comparable manner to reproduce the corresponding view of a larger number of views.

The filter elements of the optical barrier 22 are arranged in this embodiment and also in the exemplary embodiments described below such that the filter elements of each of the primary colors red, green or blue each form a pattern of strips running in the direction of the columns of the pixel matrix 21. These strips may each be formed by a single filter element, if the optical barrier 22 has a corresponding comb-like structure with vertically oriented elongate filter elements. However, they can also be formed in each case from one column or a plurality of directly adjacent columns of a plurality of filter elements, if the optical barrier is formed by a matrix of filter elements arranged in rows and columns. The strips formed by filter elements of red color each have an R in FIG. 3 and the following figures, via which filter elements of green color each have a G and the strips formed by filter elements of blue color each have a B. Opaque switched filter elements or Strips of opaque switched filters are illustrated in this and the following figures by vertical black bars.

The two reproductions of the imaged section of the pixel matrix 21 with the optical barrier 22 in front of it in FIG. 3 below illustrate which regions of the pixel matrix are visible from an eye position within one of the two viewing zones 25. Due to the wavelength genselektivität of the filter elements and the fact that in this case each half of the filter elements are opaque, from this eye position only pixels are visible on which the first view is displayed, while the pixels on which the second view is displayed - including in particular pixels visible from the other viewing zone - are not visible from this eye position, either because of the wavelength selectivity of the preceding filter elements, which are not opaque, but have a different color (the affected pixels are hatched), or due to occlusion through the opaque filter elements.

The rapid switching between the situation shown on the left in FIG. 3 and the situation shown on the right in FIG. 3 now leads to the fact that the dark stripes caused in each case by opaque filter elements are no longer perceptible and the first view from said eye position is bright and full-surface is visible with comparatively high resolution. The same applies of course to the second view with respect to an eye position in the other viewing zone 25.

The liquid crystal display used to form the pixel matrix 21 is rotated 90 ° with respect to conventional display orientations. As a result, picture information of the displayed views can not be written line by line into the pixel matrix 21, but instead from left to right, progressively in columns. By a corresponding control of the pixel matrix 21 and the optical barrier 22 by means of the control unit 24, not only the image information of the views will be inscribed in the pixel matrix 21 from left to right by overwriting the respective previous control column by column, but the switching states will also be synchronized therewith the filter elements of the optical barrier 22 when switching between the two switching states of the optical barrier 22 in each case from left to right progressively changed stripes. Thereby, the switching of the optical barrier 22 and the changing of the driving of the pixel matrix 21 are particularly well timed, whereby dark phases can be minimized, because the changed writing of image information can be started before the switching of the optical barrier 22 is completed. 4 depicts the pixel matrix 21 and the optical barrier 22 in a representation of the screen as a multi-view display or multi-person screen, in an embodiment for the reproduction of six pairwise complementary views. In this case as well, two switching states of the optical barrier 22 are switched over and, synchronized, the control of the pixel matrix 21 is changed over between two different activation states. Thus, in each case one of the six views from one of six viewing zones 25 or 25 'is visible, which is illustrated in FIG. 4 below for an eye position in a rightmost first of the viewing zones 25, 25'.

5 shows, in a corresponding representation, the pixel matrix 21 and the optical barrier 22 in a modification of the embodiment of FIG. 4. The modification differs from the embodiment of FIG. 4 in that three immediately adjacent strips of Filter elements are switched opaque and three adjoining adjacent strips of filter elements are switched transparent. The separation of the views for visibility from each of the viewing zones 25 and 25 'functions equally in these alternative switching states of the optical barrier 22.

6 shows, in a corresponding representation, the pixel matrix 21 and the optical barrier 22 in a modification of the embodiment from FIG. 3. This modification differs in a corresponding manner from the embodiment from FIG.

3 in that in three consecutive alternating strips of filter elements are switched opaque and three adjoining adjacent strips of filter elements are switched transparent.

FIG. 7 shows a section of the pixel matrix 21 and the optical barrier 22 of the screen in a further embodiment in which three switching states of the optical barrier 22 and accordingly three activation states of the pixel matrix 21 are switched through. Here, the section of the pixel matrix 21 in the figure is left to one another in the three different activation states and to the right next to each again together with the optimum see barrier 22 shown. In this embodiment, the screen is a multi-view display for simultaneously displaying nine pairwise complementary views, each of which has one of nine views from one of nine viewing zones 25 and 25 'visible in this case. In this case, a local color balance is achieved in that the strips of the wavelength-selective filter elements are arranged in the order of RGB GBR BRG instead of the otherwise used RGB RGB RGB sequence.

FIG. 8 shows the detail of the pixel matrix 21 on the left in the figure and on the right next to it again this detail together with the optical barrier

22 for the embodiment of FIG. 7 again in one of the switching states in a slightly modified driving the pixel matrix 21 to compensate for movement of the viewer on the screen, so to adapt to a reduced viewing distance. In this case, non-integer numbers in the pixels represent an activation with intensity values which result from a view corresponding to an intermediate perspective. Effectively, the image information in this case is spread in the lateral direction in the pixel matrix 21. FIG. 9 shows a section of the pixel matrix 21 of the screen reproduced on the right in the figure, and on the left next to it again this section together with the optical barrier 22 for another embodiment of the screen. In this case, the pixel matrix 21 is distinguished by the fact that the pixels are arranged laterally one line at a time by one third of a pixel width, line by line. The closest pixels in the column direction are the same

As a result, the color is offset laterally by one third of the pixel width. As a result, a periodicity is broken, which can otherwise easily lead to the formation of disturbing Moire pattern in the superposition of the two regular grid structures formed by the pixel matrix 21 and the filter elements. In the present case, the screen is driven thereby with image information of eighteen views of lesser disparity. This achieves a radiation characteristic that is very close to a common multi-view screen, creating a perspective that changes fluently as the viewer moves laterally. Alternatively, disturbing Moire patterns can also be avoided by the fact that the filter elements formed strips are designed with wavy edges. A further possibility would be the combination with a vertical diffuser.

FIG. 10 shows a pixel row of the pixel matrix 21 in a further embodiment of the screen together with a row of filter elements of the optical barrier 22 arranged in front of it. The letters R, G and B stand for the respective base color of the filter elements, while S here and also in FIG The following figures features opaque filter elements. Numbers between 1 and 16 again represent pixels that are used to display the numbered view. In this case, a fractional period of the optical barrier 22 measured in pixel widths requires the use of a comparatively large number of different views. This fractionality also prevents spurious moire because the periodicity with which the two regular structures of optical barrier 21 and gaps between the pixels of the pixel matrix 21 overlap is interrupted or disturbed.

FIG. 11 shows, for a screen of the type shown in FIG. 1, a beam path for light emanating from the pixels of the pixel matrix 21 and falling into the viewer's space. Here, SP stands for a pixel width or a lateral offset of adjacent pixels, F for a width of the individual filter elements and T for a channel width or width of a viewing zone 25 or 25 'in a viewing distance D in front of the screen. A distance between the pixel matrix 21 and the optical barrier 22 is marked with a in FIG. 11, while L denotes a lateral offset between filter elements of the same color. This figure is to be understood as a snapshot in an operation of the screen in one of the switching states, the screen is set up here for six stereo channels, that is, for the simultaneous playback of six different views. The pixel matrix 21, the optical barrier 22 and the beam path are shown here cut at the height of a red pixel line.

FIG. 12 shows a section of a pixel row of the pixel matrix 21 with the optical barrier 22 arranged in front of it, in an embodiment in which constantly opaque regions of the optical barrier 22 are interposed between individual filter elements of the optical barrier 22

Width s remain. The width s of these constantly opaque areas has, as well the distance a between the pixel matrix 21 and the optical barrier 22, an influence on the beam path and in particular on the channel width T or the width of the individual viewing zones 25 and 25 '. This influence is illustrated in FIG. 13 where, in a representation corresponding to FIG. 11, the beam path is shown for the light emanating from the pixels of the pixel matrix 21 and falling into the viewer's space in the case where the optical barrier, as in FIG Fig. 12 has opaque gaps of width s between the filter elements. In particular, in this case, the above-described measures for reducing moires - that is to say refractions of periodicities and / or the use of diffusers - can be helpful in order not only to prevent moiré formation, but also to even better visualize noticeable brightness fluctuations in the case of lateral movement of the observer avoid.

Claims

claims

An autostereoscopic screen for displaying a number of at least two different images visible from each one of an equal number of laterally offset viewing zones (25, 25 ') in front of the screen comprising a pixel matrix (21) comprising a plurality of pixels of at least three different primary colors arranged in a plurality of rows, and an optical barrier (22) arranged in front of or behind the pixel matrix (21) arranged to impose a defined direction of propagation on the light emitted by the pixels or transmitted through the pixels and to emit that light into in each case to guide one of the different viewing zones (25, 25 '), the optical barrier (22) for this purpose having filter elements which are each transparent at least in one possible state for light of precisely one of the primary colors, characterized in that the lines of the pixel matrix ( 21) each by pixels one for all pixels of this line g Lichen basic color are formed.

A screen according to claim 1, characterized in that the filter elements of the optical barrier (22) are arranged so that the filter elements of each of the primary colors each form a pattern of vertical and / or columns extending in the direction of columns of the pixel matrix (21).

3. Screen according to one of claims 1 or 2, characterized in that it comprises a control unit (24) for driving the pixel matrix (21). which is arranged to drive the pixels of the pixel matrix (21) in response to image data of a number of different images corresponding to the number of viewing zones (25, 25 ') such that each of these images is displayed on a subset of the pixels and from each one the viewing zones (25, 25 ') is visible.

Screen according to one of Claims 1 to 3, characterized in that the filter elements can each be switched between a state transparent to light of precisely one of the primary colors and an opaque state.

Screen according to claim 4, insofar as this is dependent on claim 3, characterized in that the control unit (24) is further adapted to control the optical barrier (22) and alternately switch between at least two different switching states, wherein the switching states thereby differ from each other, the filter elements are grouped differently into groups of opaque filter elements and groups of filter elements transparent to light of the respective primary color.

Screen according to Claim 5, characterized in that the different switching states differ from one another such that in each case different regions of the pixel matrix (21) are visible through the transparent filter elements from each of the viewing zones (25, 25 ') different areas when viewed from this viewing zone (25, 25 ') are obscured or shaded by opaque filter elements which are then visible from another of the viewing zones (25, 25').

Screen according to one of Claims 5 or 6, characterized in that the control unit (24) is set up by switching through a number of different switching states of the optical barrier (22) between two and said number of viewing zones (25, 25 ').

Screen according to one of claims 5 to 7, characterized in that the control unit (24) is arranged to control the pixel matrix (21) at or after each switching between different switching states of the optical barrier (22) by redistributing the pixels to the subsets to change that each of the images after switching from the same viewing zone (25, 25 ') is visible as before switching.

Screen according to one of claims 4 to 8, insofar as these are directly or indirectly related to claim 2, characterized in that the pixel matrix (21) is arranged for column-wise writing of image information, wherein the optical barrier (22) is arranged for a stripe-type activation the filter elements.

Use of a screen according to any one of claims 1 to 9 for reproducing autostereoscopic three-dimensionally perceivable images, in which the pixels of the pixel matrix (21) are driven in response to image data of a number of viewing zones (25, 25 ') corresponding number of different views of a scene in that each of these views is displayed on a subset of the pixels and is visible from in each case one of the viewing zones (25, 25 '), wherein the views differ from each other in such a way that they complement each other in a stereo image of the scene.

Use according to claim 10, characterized in that the optical barrier (22) is alternately switched between at least two different switching states, wherein the switching states differ from each other in that the filter elements are grouped differently into groups of opaque filter elements and groups of light for In each case, different areas of the pixel matrix (21) are visible through the transparent filter elements from each of the viewing zones (25, 25 ') in the different switching states, while different areas in each case are viewed from this viewing zone (25 , 25 ') are concealed or covered by opaque filter elements. are shaded, which are then visible from another of the viewing zones (25, 25 '), wherein driving the pixel array (21) at or after each switching between different switching states of the optical barrier (22) by redistributing the pixels to the subsets so changed is that each of the views after the switching of the optical barrier (22) from the same viewing zone (25, 25 ') is visible as before the switching.

12. Use according to claim 11, characterized in that a number of different switching states of the optical barrier (22) lying between two and said number of views is switched through.

13. Use according to one of claims 11 or 12, characterized in that image information of the views in each case in columns in the pixel matrix (21) are inscribed, wherein switching states of the filter elements of the optical barrier (22) are each changed in strips when switching for extending in the column direction Strip of filter elements.