Display device for providing a dual display and motor vehicle with such a display device

Abstract

The invention relates to a display device (10) for providing a dual display and a motor vehicle (36) with such a display device (10).The display device comprises first pixel units (12) for providing a first display signal (20); second pixel units (14) for providing a second display signal (14); and first and second holographic optical elements (28, 30); wherein the first and second pixel units (12, 14) are arranged in a predetermined pattern on a display layer (24); wherein the holographic optical elements (28, 30) are arranged in a deflection layer (26) in front of the display layer (24); wherein the first holographic-optical elements (28) are assigned to the respective first pixel units (12), which are designed to deflect the first display signal (20) into a first spatial region (32), and the second holographic-optical elements (30) are assigned to the respective second pixel units (14), which are designed to deflect the second display signal (22) into a second spatial region (34) which is different from the first spatial region (32).

Description

[0001] The invention relates to a display device for providing a dual display and a motor vehicle with such a display device.

[0002] Display devices, particularly in motor vehicles, that show different content for the driver and front passenger are known as "dual view displays." These dual displays typically use a parallax barrier that allows the view from the left and right to different pixels of the display. The parallax barrier is a fixed physical barrier or an upstream liquid crystal layer that can be switched to be translucent or opaque as needed, thus electronically controlling the viewing angles of the respective display signals.

[0003] A disadvantage of these dual displays is their low efficiency due to the parallax barrier structure. Part of the light is absorbed by the parallax barriers. This requires a high backlight output, which leads to high energy consumption and significant heat generation. Furthermore, crosstalk between display signals on both sides is still visible.

[0004] A dual display system is known from US 2013 / 0 222 734 A1. The dual display system comprises a liquid crystal display panel, a backlight unit that emits light onto the liquid crystal display panel, and an optical device that directs light from the backlight unit alternatively in left and right directions from the liquid crystal display panel.

[0005] US 2022 / 0 155 631 A1 discloses a display module and a method for operating the same, as well as a display apparatus and a motor vehicle. The display module comprises a backlight component and a display component and a light adjusting component arranged on one side of the backlight component and facing a light emission direction of the display module. The backlight component comprises a first light guide structure and a light adjusting structure. The light adjusting component comprises first and second electrodes, and a first liquid crystal. The display module has a split mode and a privacy mode. In the split mode, the first electrode and the second electrode are not supplied with power, and the first liquid crystal is in a wide viewing angle state. In the privacy mode, the first electrode and the second electrode control the first liquid crystal in a narrow viewing angle state.

[0006] Furthermore, the publication Trayner, David, Orr, Edwina: “Developments in autostereoscopic displays using holographie optical elements”, in SPIE, Vol. 3012: “Stereoscopic displays and virtual reality systems”, Volume IV, pp. 167-174 (1997), discloses an improved optical design of holographic optical elements (HOEs) with the possibility of using LEDs as light sources and generating 3D images with the holographic optical elements.

[0007] In addition, the document US 5 521 724 A discloses an automatic 3D video display in real time with holographic optical elements.

[0008] The object of the invention is to provide an improved display device for a dual display.

[0009] This object is achieved by the independent patent claims. Advantageous developments of the invention are disclosed in the dependent patent claims, the following description, and the figures.

[0010] One aspect of the invention relates to a display device for providing a dual display. The display device comprises first pixel units for providing a first display signal, second pixel units for providing a second display signal, and first and second holographic optical elements. The first and second pixel units are arranged in a predetermined pattern on a display layer, and the holographic optical elements are arranged in a deflection layer in front of the display layer. The first holographic optical elements, which are designed to deflect the first display signal into a first spatial region, are assigned to the respective first pixel units, and the second holographic optical elements, which are designed to deflect the second display signal into a second spatial region that differs from the first spatial region, are assigned to the respective second pixel units.

[0011] In other words, to create a dual display, a deflection layer with holographic-optical elements is used, which deflect the display signal of the first pixel units into a first spatial region and the second display signal of the second pixel units into a different, second spatial region. In this case, a fixed assignment of the holographic-optical elements to the predetermined pattern of the pixel units on the display layer can be provided, which is in particular static, and thus the display signal from each pixel is always deflected in the direction predetermined by the holographic-optical element. The predetermined pattern with which the first and second pixel units are arranged on the display layer can, for example, be an alternating sequence of the respective pixel units in order to provide each spatial region with an identical brightness signal.The first and second pixel units may, for example, be provided in alternating columns or offset from one another row by row.

[0012] The holographic optical elements (HOEs) can be provided as transmission elements whose holographic properties modify optical signals. They can replace conventional lenses, mirrors, gratings, and prisms. However, the holographic properties, such as wavelength selectivity and dependence on the angle of incidence of the light, are particularly advantageous. This means that different diffraction of the light is possible depending on its wavelength, which enables the deflection of different wavelengths in different directions. In other words, the respective holographic optical element can be designed to be directionally selective or angle-selective with respect to the incident light. Thus, only light, in particular a portion of the light, that falls onto the holographic optical element from a predetermined direction of incidence, for example, perpendicular, is deflected, in particular at a predetermined angle.Furthermore, the holographic-optical element can be wavelength-selective or frequency-selective. This means that only light with a predetermined wavelength is deflected or diffracted in the predetermined direction. Therefore, a respective holographic-optical element can particularly preferably be provided for a respective color pixel of the respective pixel units, which deflects only the respective color component in the predetermined direction in order to provide the display signal for the first or second spatial region.

[0013] The first and / or second display signal can comprise a respective image signal to be displayed for the respective spatial area. In particular, in a motor vehicle, the first spatial area can be provided for a driver of the motor vehicle and the second spatial area for a passenger. In this case, entertainment displays, in particular moving images, are to be hidden for a driver and provided only for the second spatial area of ​​the passenger.

[0014] The invention provides the advantage of achieving improved efficiency of the dual display, particularly compared to dual displays based on a parallax barrier, since the entire display signal is deflected in the corresponding direction without having to block any areas. Furthermore, a simplified design is achieved because the static arrangement eliminates the need to provide a control signal, for example, to change the orientation of a liquid crystal layer to deflect the display signal.

[0015] Furthermore, it is envisaged that the pixel units are designed as quantum dot LEDs (light-emitting diodes) or have a quantum dot color filter. Quantum dot technology provides nanocrystals that trigger quantum mechanical processes and thereby emit light. The frequency of the light depends on the size of the quantum dots, allowing different, very narrow-band wavelengths to be generated. For example, in a quantum dot LED, quantum dots excited by voltage (electroluminescence) can be excited in such a way that they act as emitters, providing narrow-band light of a first wavelength. Thus, a color spectrum intended for the pixel unit, for example, red, green, or blue, can be generated by respective color pixels provided as quantum dots.In the case of a quantum dot color filter, the respective quantum dot can be excited by light (photoluminescence), allowing light from a backlight to be converted into the desired spectrum by the quantum dot color filter. Here, too, a very narrowband frequency of light can be generated for the display signal. This has the advantage of allowing very narrowband light to be generated, which is particularly suitable for the wavelength dependence of holographic optical elements. This means that the spatial region into which the display signal is to be deflected can be specified very precisely, further improving the display.

[0016] Furthermore, it is provided that the respective pixel units comprise color pixels that are designed to provide a respective color signal, in particular red, green, and blue, for the respective display signal. Furthermore, the holographic-optical elements can be arranged and designed to deflect the respective color signal of the color pixels in the spatial direction intended for the pixel units. This means that the first holographic elements of the first pixel unit can be further subdivided so that they can deflect the color signals of the color pixels of the first pixel unit into the first spatial region. Accordingly, the second holographic-optical elements of the second pixel unit can be subdivided for the respective color pixels of the second pixel unit. This is used together with quantum dot LEDs or quantum dot color filters, which generate a narrowband color signal that can be deflected by the respective holographic-optical element.The color pixels provided here are preferably red, green and blue color pixels, which can generate the display signal of the respective pixel unit by means of light mixing.

[0017] Furthermore, it is provided that a color filter layer is arranged between the display layer and the deflection layer, which color filter layer is designed to transmit only the color signal of the respectively assigned color pixel. This is particularly preferred if a quantum dot color filter is used to generate the color signal, which is excited by a backlight. In this case, it can happen that a portion of the backlight passes through the quantum dot color filter without wavelength conversion, wherein this portion can be filtered out by the color filter layer. The color filter layer refers to a conventional color filter that only transmits light with a predetermined wavelength and filters out other wavelengths. This embodiment offers the advantage that a display image of the display device can be further improved.

[0018] The invention also includes embodiments which provide additional advantages.

[0019] Preferably, the color pixels of the first pixel unit are arranged interlaced with the color pixels of the second pixel unit. In this case, the color pixels can, for example, be arranged alternately. In other words, the color pixels of the respective pixel units can be arranged intermixed. For example, the first pixel unit can comprise the color pixels R1, G1, B1 and the second pixel unit R2, G2, B2, with an exemplary arrangement providing a sequence with R1-R2, G1-G2, B1-B2 or R1-G2, R2-G1, G2-B1, G1-B2. Alternatively, the color pixels can also be provided in the form of a Bayer matrix. This results in the advantage that an improved resolution can be provided for the display device.

[0020] A further embodiment provides for the first and second pixel units to be arranged alternately on the display layer. This means that they can be arranged alternately in the row and / or column directions.

[0021] A further embodiment provides for the first and second pixel units to be arranged in vertical or horizontal stripes on the display layer. This means that a first stripe can be provided in, for example, the vertical direction, comprising the first pixel units, followed by a second stripe in the vertical direction, comprising the second pixel units. This scheme can be continued to provide the display layer. This offers the advantage of enabling simplified production of the display layer, which saves costs.

[0022] A further embodiment provides that additional third pixel units are provided, each with associated holographic-optical elements configured to deflect the display signal generated by the third pixel units into a third spatial region. In other words, a further display signal can be deflected into a third spatial region. Particularly preferably, the third pixel units can also be configured to generate the first or second display signal, wherein the third spatial region then corresponds to the first or second spatial region. Thus, a stereoscopic effect can be provided, which can generate a three-dimensional display image for the specified spatial region.

[0023] A further aspect of the invention relates to a motor vehicle with a display device as described above. The display device can be arranged, for example, in a dashboard of the motor vehicle, in particular as a display of an infotainment system of the motor vehicle. The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus.

[0024] In the motor vehicle according to the invention, it is preferably provided that the first spatial area is a driver position and the second spatial area is a passenger position, wherein entertainment displays are excluded from the first display signal during a journey. The dual display provided can thus provide different display signals for the driver position and the passenger position. Preferably, the driver position can only comprise information displays, for example from a navigation device, and entertainment displays, in particular moving displays such as films, can be excluded for the driver position during a journey. For this purpose, for example, a control unit can be provided which checks whether the motor vehicle is moving, wherein the entertainment displays can then be excluded for the driver position. For the passenger position, however, all available display signals can be enabled.This has the advantage of increasing vehicle safety because the driver is not distracted while driving.

[0025] The invention also includes the control device for the motor vehicle. The control device can have a data processing device or a processor device that is configured to control the display device, in particular the display signals. For this purpose, the processor device can have at least one microprocessor and / or at least one microcontroller and / or at least one FPGA (Field Programmable Gate Array) and / or at least one DSP (Digital Signal Processor). In particular, a CPU (Central Processing Unit), a GPU (Graphical Processing Unit), or an NPU (Neural Processing Unit) can be used as the microprocessor. Furthermore, the processor device can have program code that is configured to control the display device when executed by the processor device. The program code can be stored in a data memory of the processor device.The processor device can be based, for example, on at least one circuit board and / or on at least one SoC (System on Chip).

[0026] The invention also includes further developments of the motor vehicle according to the invention that have features already described in connection with the further developments of the display device according to the invention. For this reason, the corresponding further developments of the motor vehicle according to the invention are not described again here.

[0027] The invention also encompasses combinations of the features of the described embodiments. The invention therefore also encompasses implementations that each have a combination of the features of several of the described embodiments, unless the embodiments are described as mutually exclusive.

[0028] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 a schematically illustrated display device; Fig. 2 a motor vehicle with the display device.

[0029] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that can be considered independently of one another, each of which also develops the invention independently of one another. Therefore, the disclosure is intended to encompass combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0030] In the figures, the same reference symbols denote elements with the same function.

[0031] In Fig. 1 schematically illustrates a display device 10 for providing a dual view display. The display device 10 has a plurality of first pixel units 12 and second pixel units 14. The first pixel units 12 may include color pixels 16, in particular color pixels 16 for red, green, and blue. Likewise, the second pixel units 14 may include respective color pixels 18.

[0032] The first pixel unit 12 can be configured to generate a first display signal 20, in particular the color signals required for the display signal, using the color pixels 16, so that a first image is provided. Likewise, the second pixel units 14 can generate a second display signal 22 using the color pixels, which can preferably differ from the first display signal 20.

[0033] The respective pixel units 12, 14 can be arranged according to a predetermined pattern on a display layer 24, wherein the predetermined pattern comprises, for example, an alternating arrangement of the first and second pixel units 12, 14, in particular in the form of vertical or horizontal stripes, or the respective color pixels 16, 18 can be interlaced, which means that first a color pixel 16 of the first pixel unit 12 is arranged on the display layer 24, followed by a color pixel 18 of the second pixel unit 14, etc.

[0034] The respective color pixels 16, 18 of the display layer 24 can particularly preferably be formed as quantum dot LEDs or by means of a quantum dot color filter, so that a respectively generated color signal is provided in a very narrow-band wavelength range.

[0035] A deflection layer 26 can be provided in front of the display layer 24, which comprises at least first holographic-optical elements 28 and second holographic-optical elements 30. The first holographic-optical elements 28 of the deflection layer 26 are assigned to the first pixel units 12 and are designed to deflect the first display signal 20 generated by the first pixel unit 12 into a predetermined first spatial region 32. In this case, the first holographic-optical elements 28 can preferably be designed to be frequency-selective according to a wavelength of the generated color signal of the color pixels 16 in order to deflect the respectively generated color signal into the first spatial region 32. Since the color signals are preferably generated using quantum dot technology, which generates very narrow-band wavelengths, this deflection can be provided very precisely by the first holographic-optical element 28.

[0036] Accordingly, the deflection layer 26 may have second holographic-optical elements 30 which are designed to deflect the second display signal 22 of the second pixel units 14, in particular the respective color pixels 18 of the second pixel units 14, into a second spatial region 34 which preferably differs from the first spatial region 32.

[0037] Optionally, an additional color filter layer (not shown) may also be provided between the display layer 24 and the deflection layer 26, which is associated with respective color pixels 16, 18 and is configured to transmit only the color signal of the associated color pixel 16, 18 and to filter out the remaining color signals.

[0038] Overall, a dual display can thus be provided for providing different display signals 20, 22 in different spatial areas 32, 34.

[0039] In Fig.2 shows a schematically illustrated motor vehicle 36 with the display device 10 according to an exemplary embodiment. In this embodiment, the display device 10 can be provided in a dashboard of the motor vehicle 36, for example as a screen of an infotainment system of the motor vehicle 36. Preferably, it can be provided that the first pixel units 12 emit the first display signal 20 into the first spatial region 32, in which a driver position 38 of the motor vehicle 36 can be located. The second pixel units 14, on the other hand, can emit the second display signal 22 into the second spatial region 34, in which, in this example, a passenger position 40 can be located.

[0040] To prevent the driver from being distracted during a journey, a predetermined restriction can be specified for the first display signal 20, in particular, that entertainment displays are not provided for the driver position 38 during a journey. Particularly preferably, only information displays can be provided for the driver position 38 by the display device 10. For the passenger position 40, however, information and entertainment displays can be provided without restrictions.

[0041] In a further embodiment, the display device 10 may additionally comprise third pixel units (not shown) with respectively associated holographic-optical elements, which are designed to deflect the display signal generated by the third pixel unit into a third spatial region. The third spatial region may, for example, be another passenger position in the motor vehicle 36, or the third spatial region may be the front passenger position 40, thereby creating a stereoscopic effect in which two display signals are provided to each eye of the front passenger, thus creating a three-dimensional effect.

[0042] In another example, holographic-optical elements 28, 30 are used to create a dual-view display (display device 10). Narrowband color pixels 16, 18 with quantum dot (QD) technology are used for this purpose. A region of a corresponding holographic-optical element can be located in front of each QD color pixel, which deflects the light in the desired viewing direction. The holographic-optical element is designed such that the regions of the pixels intended for the driver are deflected toward the driver, and the pixels assigned to the passenger are deflected toward the passenger. This allows two different image contents to be generated on one display. Furthermore, brightness is higher and energy consumption is lower than with parallax barrier technology.

[0043] This allows a passenger, for example, to watch a movie on the center display while the driver sees a different display, such as navigation, on the same screen. The display can be a conventional LCD or OLED display with color filters using QD technology. An electrically excited QD display or a micro-LED display with QD LEDs is also conceivable. This utilizes the narrow bandwidth of the light emitted by the QD pixels.

[0044] A holographic optical element is used in front of the display, which deflects the wavelengths of the respective subpixels (red, green, blue) in a desired direction. In particular, the holographic optical element's ability to deflect a specific wavelength in a defined direction is used. This means that the holographic optical element is designed so that pixels are alternately deflected to the right and to the left. The holographic optical element is designed so that the wavelengths of the red, blue, and green pixels are alternately deflected in the same direction. The pixels assigned to the driver and front passenger can, for example, be arranged on the display in stripes or in a staggered pattern.

[0045] Overall, the examples show how the invention can provide a dual view quantum dot display.

Claims

[1] Display device (10) for providing a dual display, comprising - first pixel units (12) for providing a first display signal (20); - second pixel units (14) for providing a second display signal (22); and - first and second holographic optical elements (28, 30); - wherein the first and second pixel units (12, 14) are arranged in a predetermined pattern on a display layer (24); - wherein the holographic optical elements (28, 30) are arranged in a deflection layer (26) in front of the display layer (24); - wherein the first holographic-optical elements (28) are assigned to the respective first pixel units (12), which are designed to deflect the first display signal (20) into a first spatial region (32), and the second holographic-optical elements (30) are assigned to the respective second pixel units (14), which are designed to deflect the second display signal (22) into a second spatial region (34) which differs from the first spatial region (32), - characterized byin that the pixel units (12, 14) have a quantum dot color filter, the respective pixel units (12, 14) comprise color pixels (16, 18) which are designed to provide a respective color signal, in particular red, green and blue, for the respective display signal (20, 22), and a color filter layer is arranged between the display layer (24) and the deflection layer (26), which color filter layer is designed to transmit only the color signal of the respectively assigned color pixel (16, 18). [2] Display device (10) according to claim 1, wherein the pixel units (12, 14) are designed as quantum dot LEDs. [3] Display device (10) according to one of the preceding claims, wherein the holographic-optical elements (28, 30) are arranged and designed to deflect the respective color signal of the color pixels (16, 18) in the spatial direction (32, 34) provided for the pixel units (12, 14). [4] Display device (10) according to claim 3, wherein the color pixels (16) of the first pixel unit (12) are arranged interlaced with the color pixels (18) of the second pixel unit (14). [5] Display device (10) according to one of the preceding claims, wherein the first and second pixel units (12, 14) are arranged alternately on the display layer (24). [6] A display device (10) according to any one of the preceding claims, wherein the first and second pixel units (12, 14) are arranged in vertical or horizontal stripes on the display layer (24). [7] Display device (10) according to one of the preceding claims, wherein additionally third pixel units are provided with respectively associated holographic-optical elements which are designed to deflect the display signal generated by the third pixel units into a third spatial region. [8] Motor vehicle (36) with a display device (10) according to one of the preceding claims. [9] Motor vehicle (36) according to claim 8, wherein the first spatial area (32) is a driver position (38) and the second spatial area (34) is a passenger position (40), wherein for the first display signal (20) entertainment displays during a journey are excluded.

Images