Apparatus and method for displaying images visible from various viewing angles

Abstract

The invention relates to an apparatus (100) for displaying images visible from various viewing angles, comprising: a backlighting unit (102) for emitting non-directed backlight; an optical unit for directing beams, in particular a lens sheet (106) comprising lenses (114), each of the lenses (114) being designed to deflect light beams of the backlight as directed light bundled in a light direction onto an image generating layer (108), the image generating layer (108) being designed for temporally successively generating images (743, 744), a projection device of an image currently being generated by the image generating layer (108) being dependent on the light direction (230, 231) of the directed light; a blocking layer (104), which is arranged between the backlighting unit (102) and the lens sheet (106), the blocking layer (104) comprising a grid of regions (1404) which can be switched between a light-permeable state and a light-impermeable state; and an adjustment device (110) designed to determine a selection of the light-impermeably switched regions of the regions (1404).

Description

[0001] Description

[0002] Title and procedure for of images visible from different angles

[0003] State of the art

[0004] The invention is based on a device or method according to the class of the independent claims. The present invention also relates to a computer program.

[0005] Today, various display devices are used everywhere to present information to viewers, such as mobile phones, computers, televisions, automotive instrument clusters, etc. In many applications, the displays are viewed by a group of people. Therefore, there is a growing need for new multi-user display applications.

[0006] Disclosure of the invention

[0007] Against this background, the approach presented here provides a device for displaying images visible from different viewing angles, a method for displaying images visible from different viewing angles, and finally, a corresponding computer program according to the main claims. The measures listed in the dependent claims enable advantageous refinements and improvements of the device specified in the independent claim. With the proposed concept, different groups of people can view different content on a screen simultaneously.

[0008] A device for displaying images visible from different viewing angles has the following features: a backlight unit for emitting non-directional backlight; an optical unit for directing the rays, in particular a lens sheet with an arrangement of lenses, each of the lenses being designed to deflect light rays of the backlight as directed light in a bundled light direction onto an image generator layer, the light direction being determined by a relative position between the lens and an origin of the light rays on the backlight unit assigned to the lens; the image generator layer for generating images in temporal succession, the projection direction of an image currently generated by the image generator layer depending on the light direction of the directed light;a barrier layer arranged between the backlight unit and the lens sheet, wherein the barrier layer has a grid of regions switchable between a light-transmitting state and an opaque state, wherein the barrier layer is configured to switch a selection of the regions defined by the selection signal to the opaque state using a selection signal; a setting device configured to define the selection of the regions and to provide the selection signal defining the selection to an interface to the barrier layer;

[0009] The device can be designed, for example, as a display for a vehicle, a television, a laptop, or another imaging device. Advantageously, two or more people can view the device from different angles and see different images. The backlight unit, the barrier layer, the lens sheet, and the image generator layer can each be designed in layers and arranged in a stacked manner. The image generator layer can be arranged on a surface of the device visible to a viewer. The backlight unit can provide backlighting for the image generator layer in accordance with known displays. The backlight unit can be designed as a segmented backlight unit in which individual segments can be switched on and off independently.The image generator layer can comprise an array of pixels that can be suitably controlled to generate an image, similar to known displays. The lens sheet can be used to focus diffused light from the backlight and direct the directed light onto the pixels of the image generator layer. If light from the backlight hits the lens sheet from different directions, the light can be redirected by the lens sheet in different light directions. Using the barrier layer, the light from the backlight can be filtered so that light rays from the backlight passing through the barrier layer only hit the lens sheet from a defined direction and are thus redirected by the lens sheet only in a defined light direction. For this purpose, the regions of the barrier layer can be suitably switched.For example, a defined pattern of regions in the opaque state can be formed. Advantageously, a corresponding pattern can be varied using the adjustment device to vary one projection direction of an image generated by the image generator layer. If images belonging to different image sequences, for example, two different television programs, are generated from the projection direction in time-division multiplex, the adjustment device can be configured to switch the regions of the barrier layer between a first pattern and a second pattern synchronously with the generation of the images of the different image sequences.In this way, images of a first image sequence can be captured by a first person from a first viewing angle and images of a second image sequence can be captured by a second person from a second viewing angle, wherein the first person cannot capture the images of the second image sequence and the first person cannot capture the images of the first image sequence.

[0010] The lens sheet represents an optical unit for directing beams. The lens sheet can be shaped in a manner suitable for implementing this function. For example, the lenses can be shaped as plano-convex cylindrical lenses. Alternatively, the lens sheet can be shaped as a microlens array, and the lenses can be shaped as microlenses of the microlens array.

[0011] For example, the image generator layer can be formed as a liquid crystal display. This is an established technology. Alternatively, another technology that may become available in the future could be used for the image generator layer.

[0012] The barrier layer can be formed as a liquid crystal display. For example, each region of the barrier layer can be formed by a pixel of the liquid crystal display. Such a barrier layer is inexpensive to implement. Alternatively, each region of the barrier layer can be assigned a flap manufactured using microsystem technology. When a corresponding flap is closed, light from the backlight striking the flap can be completely absorbed and thus filtered out.

[0013] The adjustment device can be designed to define a first selection of the regions for setting a first projection direction of the image generator layer. The first selection can be defined such that those light rays from the backlighting unit whose starting points have a first relative position to the lenses respectively assigned to the starting points can pass through the barrier layer. Correspondingly, the first selection can be defined such that those light rays from the backlighting unit whose starting points have a second relative position to the starting points of the lenses respectively assigned to the starting points that differs from the first relative position cannot pass through the barrier layer. In other words, the first selection can ensure that only those light rays from the backlighting that strike the lens sheet from a first direction can pass through the barrier layer.

[0014] The adjustment device can be designed to define at least a second selection of the regions for setting at least one second projection direction of the image generator layer that deviates from the first projection direction. The second selection can be defined such that those light rays from the backlighting unit whose starting points have the second relative position to the starting points of the respective associated lenses can pass through the barrier layer. Accordingly, the second selection can be defined such that those light rays from the backlighting unit whose starting points have the first relative position to the starting points of the respective associated lenses, deviating from the second relative position, cannot pass through the barrier layer.In other words, the second selection can ensure that only those light rays from the backlight that hit the lens sheet from the second direction can pass through the barrier layer.

[0015] The approach described can be extended to other projection directions in a similar way. In principle, the underlying technology allows for even faster elements to work with multiple images, for example, four images. This also allows for four different directions. Thus, additional directions for additional people can also be controlled in a similar way, for example, third and fourth directions.

[0016] The adjustment device can be designed to receive a tracking signal via an interface to a tracking device, wherein the tracking signal indicates a position of a person in the vicinity of the image generator position. The adjustment device can be designed to determine the selection of the regions using the tracking signal. In this way, the regions of the barrier layer can be switched such that the image generated by the image generator position is projected towards the person. If the tracking device is designed to track two people in the vicinity of the image generator position, the tracking signal can indicate a first position of a first person and a second position of a second person in the vicinity of the image generator position.Accordingly, the adjustment device can be configured to determine a first selection of the regions at a first time using the tracking signal in order to switch the regions of the barrier layer such that a first image generated by the image generator position is projected toward the first person, and can be configured to determine a second selection of the regions at a second time using the tracking signal in order to switch the regions of the barrier layer such that a second image generated by the image generator position is projected toward the second person. In this way, the images can be continuously tracked to the changing positions of the persons.

[0017] The adjustment device can be configured to receive an adjustment signal via an interface to a mobile device. The adjustment signal can indicate an instruction for adjusting a current selection of the regions. The adjustment device can be configured to specify the selection of the regions using the adjustment signal. The mobile device can be a remote control, for example. In this way, a person can adjust the selection of the regions of the barrier layer such that an image generated by the image generator layer is projected in such a way that it can be optimally viewed by the person.

[0018] The device can comprise an image capture device that can be configured to capture the surroundings of the image generator layer. The device can be configured to image the surroundings using an image currently generated by the image generator layer. The image can make it easier for a person to adjust the selection of the barrier layer regions, for example, using a mobile device, so that an image generated by the image generator layer is projected in such a way that it can be optimally viewed by the person.

[0019] The image capture device can thus capture the surroundings and map them onto the image generator layer. According to one embodiment, a user can then select the directions for the individual images based on this image. For example, a user sees a camera image of a sofa with two users. The user is given the option of using a remote control to move a bar for the direction in which user 1 is sitting and then do the same for user 2. Additionally or alternatively, the scene can be evaluated and artificial intelligence can be used to determine the directions without user interaction.

[0020] In addition, the first and second projection directions can be predefined. This is advantageous for applications with predefined beam directions.

[0021] A method for displaying at least two images visible from different viewing angles using a said device comprises the following steps:

[0022] Defining a first selection of the areas to project a first image generated by the image generator layer in a first projection direction; and

[0023] Defining at least a second selection of the regions to project a second image generated by the image generator layer in a second projection direction different from the first projection direction.

[0024] With this technology, more than two directions are possible in principle if the components are fast enough. For example, 240 Hz would allow four directions and thus four images.

[0025] The setting steps can be repeated alternately to enable alternating image projection in the first and second projection directions. Synchronously with the setting steps, the first and second images, or first images of a first image sequence and second images of a second image sequence, can be generated alternately by the image generator layer. This method can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, for example, in a control unit.

[0026] Also advantageous is a computer program product or computer program with program code that can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used to carry out, implement and / or control the steps of the method according to one of the embodiments described above, in particular when the program product or program is executed on a computer or a device.

[0027] Examples of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows:

[0028] Fig. 1 is a schematic representation of a device 100 for displaying images visible from different viewing angles according to an embodiment;

[0029] Fig. 2 shows a function of a cylindrical lens of a lens sheet according to an embodiment;

[0030] Figs. 3 and 4 show a backlight according to an embodiment;

[0031] Fig. 5 is a schematic representation of a device according to an embodiment;

[0032] Fig. 6 is a schematic representation of a device according to an embodiment;

[0033] Fig. 7 shows a representation of a device in the form of a television with a tracking device according to an embodiment; Figs. 8 and 9 show a representation of a device in the form of a television with a mobile device according to an embodiment;

[0034] Fig. 10 is a representation of a device in the form of a television with an image capture device according to an embodiment;

[0035] Fig. 11 is a representation of a device in the form of a television according to an embodiment;

[0036] Figs. 12 and 13 are views of a backlight unit according to an embodiment;

[0037] Figs. 14 and 15 are views of a portion of a barrier layer according to an embodiment;

[0038] Fig. 16 is a representation of a device in the form of a television according to an embodiment; and

[0039] Fig. 17 is a flowchart of a method according to an embodiment.

[0040] In the following description of advantageous embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, whereby a repeated description of these elements is omitted.

[0041] Fig. 1 shows a schematic representation of a device 100 for displaying images visible from different viewing angles. The device 100 can be used, for example, as a screen for a vehicle or for a multimedia device, such as a television.

[0042] The device 100 comprises a stack of a backlight unit

[0043] 102, a barrier layer 104, an optical unit for directing the beams, for example in the form of a lens sheet 106, and an image generator layer 108. The image generator layer 108 can represent a surface of a screen visible to a viewer.

[0044] The backlight unit 102 is configured to emit non-directional backlight. The backlight unit 102 is configured as a segmented backlight unit in which individual segments can be independently turned on and off. For example only, the backlight unit comprises a plurality of light sources for emitting diffuse light toward the image generator layer 108.

[0045] The barrier layer 104 is arranged between the backlight unit 102 and the lens sheet 106. The barrier layer 104 has a grid of regions that can be switched between a light-transmitting state and an opaque state. For example only, the barrier layer 104 is formed as a liquid crystal display, wherein each of the regions can be formed, for example, as a pixel or a pixel group of the liquid crystal display. Alternatively, the barrier layer 104 can be formed micromechanically, wherein each of the regions is formed, for example, by a foldable flap manufactured using microsystem technology. The device 100 comprises an adjustment device 110 configured to provide a selection signal 112 to the barrier layer 104.The selection signal 112 defines a selection of the regions of the barrier layer 104 that are or will be switched to the translucent state or, alternatively, to the opaque state. The barrier layer 104 is configured to switch the selection of regions defined by the selection signal 112 accordingly, for example, from the translucent state to the opaque state.

[0046] The lens sheet 106 comprises an arrangement of lenses 114. In this and the following exemplary embodiments, the lenses 114 are embodied, for example, as plano-convex cylindrical lenses 114. Alternatively, other lens shapes can be used in the same way. For example, in an alternative exemplary embodiment, the lens sheet is shaped as a microlens array and the lenses 114 accordingly as microlenses. The lens sheet 106 is embodied, for example, as a lens foil. According to the exemplary embodiment shown, the cylindrical lenses 114 are arranged parallel to one another in a plane. According to one exemplary embodiment, adjacent cylindrical lenses 114 adjoin one another without a gap. According to one exemplary embodiment, the cylindrical lenses 114 each have a flat base surface on the side of the barrier layer 104 and an outwardly curved surface on the side of the image generator layer 108.Each of the cylindrical lenses 114 is configured to deflect the backlight emitted by the backlight unit 102 and passing through the barrier layer 104 as directed light in a focused light direction onto the image generator layer 108. The light direction in which the directed light exits a cylindrical lens 114 depends on a relative position between the corresponding cylindrical lens 114 and an origin of the light rays on the backlight unit 102 associated with the cylindrical lens 114.

[0047] For the lens array of lens sheet 106, the most convenient solution is to use glass or plastic to construct the lens structure. It should be noted that some new optical technologies can also fulfill this function. For example, liquid crystals or other special liquid materials can be used to refract light rays.

[0048] The image generator layer 108 is designed to generate images sequentially in time. The projection direction of an image currently generated by the image generator layer 108 depends on the direction of the light directed through the lens sheet 106 and incident on the image generator layer 108 from the side of the lens sheet 106. For example only, the image generator layer 108 is designed as a liquid crystal display. Pixels of the image generator layer 108 are controlled, for example, by an image signal 116, such that the image currently to be projected is generated. Optionally, the device 100 comprises a control device 118 for providing the image signal 116 to the image generator layer 108.

[0049] The image generator layer 108, embodied, for example, as an LCD screen, is designed to generate the desired image for the user. Currently, there are no other imaging technologies that could compete with LCD technology. The main function of this layer is that it must be transmissive and not scatter light, as the direction of light coming from the directional backlight must be maintained. On the other hand, to generate the image, the light transmittance must be individually controlled for each pixel, and the colors are also generated in this layer. In the future, other technologies that fulfill these functions could also be used for the presented approach.

[0050] Depending on the projection direction of the image generated by the image generator layer 108, the image is visible to a viewer from different positions. By setting a suitable projection direction, the image can thus, for example, be visible exclusively from a specific viewing angle. The device 100 is configured to adjust the projection direction using the barrier layer 104, in particular by a suitable selection of regions that are switched to be opaque or transparent.

[0051] According to one embodiment, the adjustment device 110 is configured to define a first selection of regions for setting a first projection direction of the image generator layer 108, and to define a second selection of regions that differs from the first selection for setting at least one second projection direction of the image generator layer that differs from the first projection direction, and to provide the selection signal 112 defining the respective selection to the barrier layer 104. For example, the adjustment device 110 is configured to make the corresponding selection based on a predetermined selection rule that, for example, assigns different selections to different projection directions.

[0052] Other projection directions can be set in a similar way.

[0053] According to one embodiment, the setting device 110 is designed to send a tracking signal 120 via an interface to a

[0054] Tracking device to receive, for example, a position of a person viewing an image generated by device 100 can be tracked. Accordingly, tracking signal 120 can indicate a position of a person in the vicinity of image generator position 108. According to this exemplary embodiment, setting device 110 is designed to determine the selection of regions using tracking signal 120. For example, setting device 110 is designed to determine, based on the determined current position of the person, a projection direction of device 100 suitable for the current position and to define a selection of regions of barrier layer 104 that are switched to be opaque, suitable for achieving the projection direction.If the device 100 is used by two people to whom different images are displayed, the tracking device is used according to one embodiment to track both people. Accordingly, in such a case, the tracking signal 120 indicates a first position of a first person and additionally a second position of a second person in the vicinity of the image generator layer 108, and the setting device 110 is configured to define the first selection of the regions and the second selection of the regions of the barrier layer 104 using the tracking signal 120 such that an image intended for the first person is projected toward the first position and an image intended for the second person is projected toward the second position.By continuously updating the tracking signal 120, a projection direction suitable for the first person and a projection direction suitable for the second person can be continuously adapted to changing positions. This approach can be extended accordingly to multiple people, for example, to three, four, or more people. Higher frequencies can be used for this purpose, for example, a frequency of 240 Hz.

[0055] According to one embodiment, the adjustment device 110 is configured to receive an adjustment signal 122 via an interface to a mobile device. The adjustment signal 122 indicates an instruction for adjusting a current selection of the ranges. The adjustment device 110 is configured to specify the selection of the ranges using the adjustment signal 122. For example, the adjustment device 110 is configured to change the selection of the ranges in response to each renewed reception of the adjustment signal 122 and to store it as the selection to be used in response to the absence of a further adjustment signal 122 or in response to the receipt of a confirmation signal 123. The adjustment signal 122 and optionally the actuation signal can be provided, for example, by a user by pressing one or more buttons on a remote control.In this way, for example, a first selection of areas can be configured so that a first user or a first user group facing the same direction is optimally displayed with a first image, and then a second selection of areas can be configured so that a second user or a second user group facing the same direction is optimally displayed with a second image. As already explained, the approach described can be extended accordingly to other users or user groups.

[0056] If the device 100 has an image capture device, as shown, for example, in Fig. 10, according to one embodiment, an environment of the image generator layer 108 is captured. The captured image of the environment is first projected using the image generator layer to set suitable projection directions of the device 100. A user can adjust the barrier layer 104 based on the displayed image, for example, by providing the adjustment signal 122 using a mobile device, such as a remote control.

[0057] The device 100 may also be referred to as a time-division, full-resolution split-view display. The device 100 may be used in conjunction with display devices that present information to viewers, such as mobile phones, computers, televisions, automotive instrument clusters, etc. In particular, the device 100 is suitable for applications in which displays are viewed by a group of people, so-called multi-user display applications. An example of such products is a central information display with split-view functionality for a vehicle, in which the driver and front passenger can see different content on the screen. Advantageously, different images can be sent to the driver and front passenger, enabling many new display applications.For example, if the passenger is watching entertainment content, the content can be set to navigation for the driver so that the driver can continue to perceive useful information without being distracted by the entertainment content, which is also required by law.

[0058] Another example for which the device 100 can be used is a passenger information display with a switchable privacy function. The display can operate in two modes: public mode and private mode. In public mode, both the driver and the passenger can see the same image content. In private mode, the driver sees a very dark image, and only the passenger can see the displayed image. This function also aims to reduce distraction for the driver when entertainment content is shown on the PID.

[0059] Advantageously, the device 100 can also be used in conjunction with display products such as multi-user games, such as tennis, which can be played via a television or a game console connected to a television. In such applications, different players should have a different view of the game. This effect can be achieved by the device 100.

[0060] Thus, possible applications for the split-view function include television, multi-user gaming on a laptop, a standalone monitor, a tablet, etc., or automotive displays.

[0061] The approach described here thus enables two groups of people to watch different content on one screen at the same time. Let's take the television as an example: Sometimes the husband wants to watch a football match while the wife wants to watch a movie. Or the children want to watch cartoons while the parents are interested in the world news. Unlike a split-screen function, using device 100, both groups can display different content on the same screen without affecting each other. This avoids a TV conflict without either side having to make a major compromise. For example, it can prevent the husband from forgoing the football match and watching the movie with his wife, or prevent the husband from having to use a much smaller mobile phone or tablet to watch the football match.Instead, different people, in this case husband and wife, can see different content on the display at the same time.

[0062] Advantageously, device 100 can dispense with predefined areas for an optimal viewing experience. This means that multiple users do not need to be in predefined positions. If a user moves in front of the screen, the projection direction of device 100 set for that user can be followed, so that the user does not see content intended for another user. Thus, even if the user moves in front of the screen, a privacy function can still be guaranteed. It is not necessary to divide the display pixels of image generator layer 108 into two groups, with each user only seeing one pixel group and thus only receiving half the original resolution. Instead, all display pixels can be used for each user. This avoids a reduced resolution.Furthermore, interference can be avoided because content intended for one user is not visible to all users. Thus, content that differs significantly from one another can be displayed to different users. Since each user has access to the full active area of ​​the image generator layer 108, each user can utilize the full resolution of the image generator layer 108.

[0063] Advantageously, although the approach described here is based on a display based on time-division multiplexing, it does not require users to wear shutter glasses. By eliminating the need to wear special glasses, it is quite convenient to utilize new functions of the device 100. Synchronization between multiple devices, in particular precise synchronization between the display and the glasses of multiple users, is also not necessary. This also eliminates the need for a precise eye-monitoring device, and screens with very fast switching times, such as a 240 Hz refresh rate, are also not required for two-user applications. Instead, the approach described here is based on a specially developed backlight system combined with a time-division multiplexing method. A corresponding configuration of a display unit of the device 100 is shown in Fig.1. This special backlight can be referred to as directional backlighting, which consists of three main components: the lens sheet 106, for example in the form of a lens foil, the barrier layer 104, and the backlight unit 102 serving as the backlight. The directional backlighting is capable of illuminating the image generator layer 108, which forms an image generator, with different light directions. In conjunction with head-tracking technology, the remote control, or predefined viewing positions, a high-quality split-view function can be achieved.

[0064] In terms of real-world application, several advantages arise. For example, the proposed concept allows different groups of people to view different content on a screen simultaneously. This method can lead to the following technical improvements:

[0065] First, an image can be displayed at full resolution. The entire image on the image generator layer 108 is projected in one direction at a specific time. This allows the viewer's eye to see all of the image generator's pixels.

[0066] In addition, no glasses are required, and synchronization can be performed within the display unit of the device 100.

[0067] Furthermore, no eye tracking is required. There are three modes of the new concept, which are explained below: first, using head tracking or body / person tracking; second, remote control; and third, using a predefined area for split-view observation. The approach described allows for a high degree of freedom. Users can move around in front of the display and still be able to perceive the split view.

[0068] The image generation layer is arranged at the top in the form of the image generator layer 108. According to one embodiment, there are no optical elements above the image generation layer, i.e., on a side of the image generator layer 108 facing away from the backlight unit 102, which could impair the image quality.

[0069] Advantageously, a low refresh rate of 120 Hz is sufficient. Such a low refresh rate reduces hardware requirements. Furthermore, a precise gaze tracking device is not required. The system design presented here offers several convenient ways to achieve a split-view function: head / body / person tracking, remote control, and a predefined field of view.

[0070] A directional backlight configuration of device 100 is described below. The innovation of the approach described here, using the barrier layer 104, for example, in the form of an additional barrier LED display, is then explained. The head / body / person tracking use case is then presented. The remote control use cases are then explained. Use cases with a predefined field of view are then demonstrated. Finally, alternative embodiments of the technology on which device 100 is based are discussed.

[0071] The concept of directional backlighting with time division multiplexing was originally intended to improve the quality of multiview 3D displays. According to the approach presented here, this concept is also used for the split-view function. The directional backlight consists of the backlight unit 102, the barrier layer 104, and the lens sheet 106 in the form of a lenticular lens foil or a lenticular lens plate. The lens sheet 106 contains a linear array of plano-convex cylindrical lenses 114.

[0072] Fig. 2 schematically shows the function of a single lens element, here also purely exemplary in the form of a cylindrical lens 114 of a lens sheet of the device shown in Fig. 1 according to one embodiment. The function is to generate directed illumination. This function can also be realized by differently designed lenses and, in general, by an optical unit for directing beams.

[0073] A first light source 202 and a second light source 203, each for emitting non-directional background light, are shown schematically in the backlight unit 102. The first light source 202 represents a first output point for emitting light rays, and the second light source 203 represents a second output point for emitting light rays that can be focused by the cylindrical lens 114 assigned to the light sources 202, 203. The cylindrical lens 114, in the form of a microlens, is designed to deflect light rays of the backlight from the first light source 202 as directed light, bundled in a first light direction 230, onto the image generator layer of the device, and to deflect light rays of the backlight from the second light source 203 as directed light, bundled in a second light direction 231, onto the image generator layer.The light directions 230, 231 result from a relative position between the cylindrical lens 114 and the starting points of the light rays, where the starting points here correspond to the positions of the light sources 202, 203 on the backlight unit 102. Thus, the light rays from the light sources 202, 203 are collimated into the specific light directions 230, 231.

[0074] Thus, the cylindrical lens 114, in conjunction with the barrier layer, can be used to control the direction of illumination in the form of the backlight unit 102. The light coming from one of the light sources 202, 203, for example, an LED or an LCD pixel, is originally diffused in all directions. When the pixel array is placed on the focal plane of the lens, here the cylindrical lens 114, the light from a pixel in the form of one of the light sources 202, 203 is focused by the lens in one direction. The deflection of the light rays is determined by the position of the pixels on the focal plane.

[0075] By placing the pixel arrangement of the light sources 202, 203 on the focal plane of the cylindrical lens 114, also referred to as a lens, the diffuse light coming from a light source 202, 203 is collimated. The direction of propagation of the light rays is determined by the position of the pixels formed by the light sources 202, 203 on the focal plane. The backlight unit 102 advantageously has a pixel- or strip-wise design, in which the output light can be controlled at the pixel level (or at the strip level). For simplification, the term "LED matrix backlight" is also used for the backlight unit 102. The image generator layer 108, for example in the form of an LCD display, is placed on the directional backlight in order to display the intended image content. The image generator layer 108 is also referred to as an image LCD, i.e. a liquid crystal layer without a backlight.

[0076] Fig. 3 and Fig. 4 show an embodiment of a directional backlight, such as could be used for 3D display applications, in a configuration adapted to create a split-view function. A normal display image (60 Hz, 16.6 milliseconds) is divided into two sub-images (120 Hz), each sub-image lasting 8.3 milliseconds (ms). In the first sub-image, based on the detected position of a first user 332, a corresponding group of LED pixels in the matrix's backlight is illuminated using the barrier layer, allowing light rays from these LED pixels to pass through the barrier layer. The light rays are focused by the lens arrangement of the lens sheet 106 and illuminate the entire upper image generator layer 108, for example, in the form of an LCD display for the first user 332.When the desired image is displayed on the image generator layer 108, only the first user 332 can see the image in a first partial image, while a second user 333 perceives a dark image. Since the entire image generator layer 108, for example in the form of an LCD screen, is projected onto the first user 332, the first user 332 can see all pixels of the image generator layer 108 in the form of an upper LCD screen and thus receives a full-resolution image. In the second partial image from 8.3 ms to 16.6 ms, shown in Fig. 4, based on the detected position of the second user 333, a different group of LED pixels should be used in the backlight of the matrix using the barrier layer. Then, the entire image generated by the image generator layer 108 is illuminated only in the direction of the second user 333.These two subframes, i.e., the display of the first image for the first user 332 and the second image for the second user 333, together last 16.6 ms, so that the entire image is still repeated at 60 Hz. Due to the persistence of vision, the eye is now also able to merge the light and dark image patterns into a continuous image perception without flickering. This configuration enables a split-view function with full image resolution. Therefore, only the first user 332 can see the image shown in the first sub-image on the image generator layer 108 and projected in a first projection direction 336. In the second sub-image, a similar configuration is used to project the image only for the second user 333 in a second projection direction 337.

[0077] Fig. 5 shows a schematic representation of the device 100 according to an embodiment. The necessity of the barrier layer 104 is demonstrated. Without the barrier layer 104, a phenomenon referred to as "side leakage" occurs. The light emanating from a light source 202, for example an LED pixel, of the backlight unit 102 is initially diffuse and spreads in all directions. Thus, if the light source 202 of the backlight unit 102 is switched on in the form of a matrix backlight, and all areas of the barrier layer 104 are switched to be light-permeable, the light from the light source 202 can strike several lenses of the lens sheet 106 and be bundled in several directions. This effect is referred to as "side leakage" or "side lob". When a group of LED pixels in the matrix backlight is activated, the LCD image is illuminated in several directions, which are shown in Fig.5 are shown as central and side views. The side leakage effect can lead to a visual conflict between multiple users. Assume that there are four LED pixels under a lens unit of the lens sheet 106. When all four LED pixels are turned on, the LCD image is illuminated in multiple directions due to side leakage. This problem can be avoided by appropriately selecting areas of the barrier layer 104 that are made opaque.

[0078] Fig. 6 shows a schematic representation of the device 100 according to an embodiment, wherein the barrier layer 104 is activated, unlike the embodiment shown in Fig. 5. This enables a practical solution for eliminating lateral scattering, so that an excellent split-view function can be achieved. The key to the new concept is the insertion of an additional light-modulating layer in the form of the barrier layer 104 between the backlight unit 102, for example in the form of a matrix backlight, and the lens sheet 106, for example in the form of a lens array. This new light-modulating layer is intended to block the light rays in the direction of the unwanted lenses of the lens sheet 106 and can be implemented using an LCD. For simplification, the barrier layer 104 can also be referred to as a barrier LCD. The functional principle of the barrier layer 104 is illustrated in Fig. 6.Please note that the size and position of the components in the figure are for illustrative purposes only and the parameters do not correspond to the real models.

[0079] The barrier layer 104 prevents the light rays from one LED pixel, for example, the light source 202, from striking multiple lenses of the lens sheet 106. Let's assume that in the real application, only the central view is to be present and the two peripheral side views shown in Fig. 5 are to be eliminated. By displaying a suitable white-black pattern on the barrier layer 104, the light rays in the direction of the two peripheral lenses are blocked, while only the rays in the direction of the central lens of the lens sheet 106 can propagate further. As a result, the image generated by the image generator layer 108 is illuminated only in the vertical direction, creating only one viewing area. The appropriate pattern on the barrier layer 104 is generated by a suitable selection of areas of the barrier layer 104 that are made opaque.The remaining areas are switched to be translucent.

[0080] If a side view is to be activated while suppressing all other views, a different white-black pattern can be displayed on the barrier layer 104 by selecting different areas of the barrier layer 104. This allows the light of the backlight unit 102, for example, the LED pixels shown, to be modulated.

[0081] For example, in the first partial image from 0 to 8.3 ms, the barrier layer 104 can block the light rays to the peripheral lenses of the lens sheet 106, so that the image generator layer 108 is illuminated only for the central view and can be perceived by the first user. During the first partial image, the second user sees a dark image on the display. In the second partial image from 8.3 ms to 16.6 ms, the barrier layer 104 should block the light rays toward the central lens, so that the image generated by the image generator layer 108 is projected only for the red user. In this way, the split-view function can be realized with a 120 Hz display and full resolution of the image LCD.

[0082] Fig. 7 shows an embodiment of device 100 in the form of a television. The following text will directly address the display concept presented here, which allows only one image to be sent in the desired direction, without repeating the entire theory.

[0083] A typical scenario for the split-view function is a large TV in the living room. There are often situations where not everyone, in this case users 332 and 333, wants to see the same content. The concept described offers a solution to potential "TV conflicts." Depending on the implementation, various scenarios are possible.

[0084] This section deals with the application when a

[0085] A tracking device 740, for example, a tracking device (head / body / person), is integrated into the system. The tracking device 740, for example, a tracking device (head / body / person), tells the system where the respective observers are located. As a first example, we can assume that the first user 332 is a man and the second user 333 is a woman sitting on a couch. The distance between the two heads of users 332, 333 could be approximately 1 m. Using the proposed technology, two different images 743, 745 can then be sent to the man and the woman, respectively.

[0086] The tracking device 740, for example, the tracking device, enables the user's position to be determined. The following methods can be used to implement the tracking function: eye tracking, head tracking, body tracking, person tracking, device tracking (e-watch, wristband, mobile phone, game controller, TV controller, etc.). Other technologies that enable position tracking can also be used.

[0087] Fig. 8 and Fig. 9 show another embodiment of device 100 in the form of a television. This shows an application for the split-view function with a mobile device 840 in the form of a remote control. In the event that no tracking device is implemented, the mobile device 840 offers a way to enable direction selection. The technically simplest method is with the help of the remote control. The process would be as follows:

[0088] The first user 332 or the first user group takes over control. Using the left / right buttons on the remote control, the first user 332 can set the broadcast directions of a TV test pattern, which are shown in the figure as red circles, for example. This setting can be completed when the first user 332 has a perfect view of the test pattern. The setting is confirmed using the remote control. To do this, the instruction to press left or right is displayed on the television screen above the concentric circles shown, for example, until a circle is perfectly visible to the first user 332 and to confirm this with OK. The remote control is passed to the second user 333 or the second user group, and a similar process is carried out. To do this, the instruction to press left or right is displayed on the television screen above the concentric circles shown, for exampleright until the circle is perfectly visible to the second user 333 and confirm with OK.

[0089] Remote control can be realized via TV controller, voice control, gesture control, smart TV app (mobile phone), gaming controller, etc.

[0090] Remote control operation can be achieved by determining, in the first step, that every fourth LED pixel of the backlight unit under each lens unit of the lens sheet should be turned on to illuminate the image for the first user 332. In the second step, the system can then determine, based on the selection of the second user 333, that every second LED pixel should be activated to provide the required illumination for the second user 333. Later, in split-view mode, every fourth LED pixel is turned on in the first sub-image and every second LED pixel is turned on in the second sub-image.

[0091] The following methods can be used for remote control, also called remote control: TV controller, voice control, gesture control, other devices: e-watch, e-bracelet, mobile phone, game controller, etc.

[0092] Fig. 10 shows a further embodiment of the device 100 in the form of a television. It shows an application for the split-view function with an image capture device 1040 in the form of a camera. In this case, the transmission directions can be selected by evaluating an image of the living room, which could be captured by a camera integrated into or attached to the television. The living room is shown on the television in real time, along with the users. Based on this image, a person can use the remote control to set the correct transmission directions for all users. Thus, the image captured by the image capture device 1040 can be projected using the image generator layer of the device 100, which is embodied here as a television, and subsequently, suitable selections of areas of the barrier layer for the users can be selected using the setting device.For this purpose, the adjustment device can, for example, use an adjustment signal that can be provided via the remote control.

[0093] For example, the TV screen displays instructions above the separation bar to press left or right to set a beam direction for the first user. This can then be repeated for the second user.

[0094] Fig. 11 shows another embodiment of device 100 in the form of a television. This illustrates a use case for the split-view function where a tracking device and remote control cannot be implemented. In this case, the split-view function can still be implemented with predefined viewing areas. As shown in Fig. 11, the viewing areas in which users 332, 333 must be located to use the split-view function can be predefined. For example, the first user 332 must sit between 60° and 80°, while the second user 333 must sit between 100° and 130°. These parameters should be set and saved in the television before the split-view function is started. In operating mode, two different images are sent to the predefined viewing areas, and users 332, 333 must find the correct positions to use the split-view functions.

[0095] This method is less flexible than the tracking method or the remote control. To use the split-view function, the respective user 332, 333 must be seated within the predefined areas. As soon as the respective user 332, 333 moves out of the predefined areas, it is no longer possible to receive the correct image, and the image quality is severely degraded. However, this method requires only a minimal amount of additional hardware implementation, which can be advantageous in some applications. On the subject of audio / sound: Almost all modern consumer electronics devices now enable wireless audio transmission to headsets (e.g., Bluetooth headsets). This way, all users can independently enjoy the TV picture with the corresponding sound.

[0096] Fig. 12 and Fig. 13 show embodiments of a backlight unit 102. The backlight unit 102 represents a lighting unit that should contain a certain number of individual light sources that can be switched on and off independently of one another. Fig. 12 shows one possible configuration, namely a matrix distribution. Fig. 13 shows another possible configuration, namely a bar distribution. As for the specific technology, the following components can be used to construct the backlight: LCD (with edge or matrix backlighting), micro-LED, mini-LED, LED array, or OLED. In the future, new light-emitting technologies may also emerge that can be used for this application.

[0097] Fig. 14 and Fig. 15 show an embodiment of a region 1404 of the barrier layer of the device. In Fig. 14, the region 1404 is opaque, and in Fig. 15, it is transparent.

[0098] The main function of the barrier layer is to block the unwanted light rays emanating from the backlight. The most mature technology is LCD technology. Other technologies capable of modulating light transmission would also be suitable for constructing the barrier layer. One example is the MEMS technology shown in Figures 14 and 15, in which one MEMS component, here for example a flap 1450, is provided perpendicular to the propagation direction of the light from the backlight unit, as shown in Figure 14. Figure 16 shows another embodiment of the device 100 in the form of a television, for applying the split-view function in games with multiple users 332, 333.Each user 332, 333 can receive a different image 743, 744 from the display, and the respective image 743, 744 occupies the entire display area at full resolution.

[0099] The described approach is based on directional backlight technology to create high-quality split-view displays. The key to the proposed directional backlight is the insertion of an additional layer between the lens array and the backlight unit to restrict the light propagation directions. A tracking device, remote control, and predefined viewing zones can then be used to define the light emission directions for the split-view function. Various new use cases can be generated from the split-view function, which can significantly enrich multi-user display applications. As explained, this invention can be applied to, but is not limited to, televisions, monitors, laptops, automotive displays, etc.

[0100] Fig. 17 shows a flow diagram of a method for displaying at least two images visible from different viewing angles using a mentioned device. In a step 1701, a first selection of the regions of the barrier layer is determined in order to project a first image generated by the image generator layer in a first projection direction. In a step 1703, at least a second selection of the regions of the barrier layer is determined in order to project at least a second image generated by the image generator layer in a second projection direction different from the first projection direction. The steps 1701, 1703 can be carried out individually or together repeatedly in order to adapt the first or second projection direction, for example in order to adapt the projection directions to changing positions of a user.

[0101] The method can be extended to additional viewing directions. Thus, according to one embodiment, in step 1703, a third selection of the regions of the barrier layer is determined in a corresponding manner in order to project a third image generated by the image generator layer in a third projection direction different from the first and second projection directions. Optionally, a fourth selection of the regions of the barrier layer is determined in a corresponding manner in order to project a fourth image generated by the image generator layer in a fourth projection direction different from the first, second, and third projection directions. Further images can be generated accordingly.

Claims

Claims 1. A device (100) for displaying images (743, 744) visible from different viewing angles, the device (100) having the following features: a backlight unit (102) for emitting non-directional backlight; an optical unit for directing the rays, in particular a lens sheet (106) with an arrangement of lenses (114), each of the lenses (114) being designed to deflect light rays of the backlight as directed light, bundled in a light direction (230, 231), onto an image generator layer (108), the light direction (230, 231) being from a relative position between the lenses and an origin of the light rays on the backlight unit (102) associated with the lenses;the image generator layer (108) for generating images (743, 744) in temporal succession, wherein a projection direction of an image currently generated by the image generator layer (108) depends on the light direction (230, 231) of the directed light; a barrier layer (104) arranged between the backlight unit (102) and the lens sheet (106), wherein the barrier layer (104) has a grid of regions (1404) switchable between a light-transmissive state and an opaque state, wherein the barrier layer (104) is designed to switch a selection of the regions (1404) defined by the selection signal (112) into the light-opaque state using a selection signal (112); a setting device (110) which is designed to determine the selection of the regions (1404) and to provide the selection signal (112) defining the selection to an interface to the barrier layer (104).

2. Device (100) according to claim 1, wherein the lenses (114) are formed as plano-convex cylindrical lenses (114), or wherein the lens sheet (106) is formed as a microlens array and the lenses (114) are formed as microlenses of the microlens array.

3. Device (100) according to one of the preceding claims, wherein the image generator layer (108) is formed, for example, as a liquid crystal display.

4. Device (100) according to one of the preceding claims, in which the barrier layer (104) is formed, for example, as a liquid crystal display or in which each region (1404) of the barrier layer (104) is assigned a flap (1450) manufactured using microsystem technology.

5. Device (100) according to one of the preceding claims, wherein the setting device (110) is designed to define a first selection of the regions (1404) for setting a first projection direction of the image generator position (108).

6. Device (100) according to claim 4, wherein the setting device (110) is designed to define a second selection of the regions (1404) that differs from the first selection in order to set at least one second projection direction of the image generator position (108) that differs from the first projection direction.

7. Device (100) according to one of the preceding claims, wherein the setting device (110) is designed to receive a tracking signal (120) via an interface to a tracking device (740), wherein the Tracking signal (120) indicates a position of a person in the vicinity of the image generator position (108), and in which the setting device (110) is designed to determine the selection of the areas (1404) using the tracking signal (120).

8. Device (100) according to one of the preceding claims, wherein the adjusting device (110) is designed to generate an adjustment signal (122) via an interface to a mobile device (840), wherein the adjustment signal (122) indicates an instruction for an adjustment of a current selection of the areas (1404), and wherein the setting device (110) is designed to determine the selection of the areas (1404) using the adjustment signal (122).

9. Device (100) according to one of the preceding claims, comprising an image capture device (1040) which is designed to capture an environment of the image generator position (108), wherein the device (100) is designed to image the environment by means of an image currently generated by the image generator position (108).

10. Device (100) according to claim 6, wherein the first projection direction and the second projection direction are predefined.

11. Device (100) according to one of the preceding claims, which is designed as a television, a laptop or another imaging device.

12. A method for displaying at least two images (743, 744) visible from different viewing angles using a device (100) according to one of the preceding claims, the method comprising the following steps: Determining (1701) a first selection of the regions (1404) in order to project a first image generated by the image generator layer (108) in a first projection direction; and Determining (1701) at least a second selection of the regions (1404) in order to convert a second image generated by the image generator layer (108) into a to project a second projection direction that differs from the first projection direction.

13. Computer program configured to execute and / or control the steps of the method according to claim 12.

14. A machine-readable storage medium on which the computer program according to claim 13 is stored.

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