DE102014000487A1 - Display device, vehicle with a display device and computer program product - Google Patents

Abstract

The invention relates to a display device which has at least one first concave mirror and one second concave mirror, wherein the second concave mirror has at least one opening. Through the two concave mirrors a convex cavity is stretched. Arranged in the cavity is a diffractive optical element having a number of optical phase modulation cells, wherein the diffractive optical element provides a hologram. The display device furthermore has a transparent touchpad which covers the at least one opening and makes it possible to input data. The display device further comprises at least one light source for illuminating the phase modulation cells of the diffractive optical element, wherein the diffractive optical element is arranged in the cavity such that radiation emanating from the at least one light source is modulated by the phase modulation cells, through the transparent touchpad on the opening passes through and reproduces a holographic image above the transparent touchpad within a defined field of view.

Description

A display device, in particular for a vehicle, is described. Further, a vehicle with a display device and a computer program product will be described.

From the EP 1 956 413 A2 For example, a holographic information display for a motor vehicle for projecting a virtual display image is known.

Such head-up displays are increasingly used to be able to display the driver visual information in a way that allows him to keep track of the road at all times.

Object of embodiments of the invention is to develop display devices, in particular in a vehicle, in terms of flexible, user-related use, and to allow interaction between driver, display device and vehicle. In particular, a display device is to be specified which can be used flexibly in a vehicle. It is another object of embodiments of the invention to provide a vehicle with such a display device and a computer program product.

According to one aspect of the invention, a display device is provided which has at least a first concave mirror and a second concave mirror, wherein the second concave mirror has at least one opening. Through the two concave mirrors a convex cavity is stretched. Arranged in the cavity is a diffractive optical element having a number of optical phase modulation cells, wherein the diffractive optical element provides a hologram. The display device furthermore has a transparent touchpad which covers the at least one opening and makes it possible to input data. The display device furthermore has at least one light source for illuminating the phase modulation cells of the diffractive optical element, wherein the diffractive optical element is arranged in the cavity such that radiation emitted by the at least one light source is modulated by the phase modulation cells and reproduces a holographic image within a defined field of view ,

The diffractive optical element (DOE) is illuminated by the, in particular coherent, radiation of the light source for reproducing the holographic image. In particular, light-emitting diodes (LEDs) or laser diodes can be used as light sources.

The display device allows the display of information as a holographic image above the transparent touchpad on the opening in the second concave mirror. In doing so, the holographic image appears visibly in a volume area, which is referred to here as the "viewing area of the holographic image" or else as the "area of the holographic image". In particular, the field of view of the holographic image may be spherical and illuminate a portion of the interior surface of a windshield of the vehicle so that the information of the holographic image is available to the driver without diminishing his attention to the traffic.

The arrangement of the DOE and possibly also of the light sources in the cavity formed by the two concave mirrors creates a very compact display device, wherein a virtual display image above the transparent touchpad on the opening is displayed on the hologram or directly on the touchpad. In the latter case, a further, remote projection surface is not required. The display device can therefore also be installed as a self-contained module in an environment that may have other display devices, for example, in the dashboard of a vehicle. The advantage of the transparent touchpad on the opening is that intercommunication is made possible for the driver in that an input of data, requests or commands can trigger a corresponding reaction. For this purpose, an internationally understandable symbolism such as icons can be provided on the touchpad, with the navigation functions, rear views, front images or other driving technology aids a driver assistance system can be called or activated.

The menu-invocable symbolism of the transparent touchpad is optically and color matched to the holographic projection and / or adjusted so that the virtual holographic image is not seriously affected. The electrically conductive structured surfaces and printed conductors of the touchpad required for the input are preferably constructed from electrically conductive optically transparent and correspondingly selectively structured indium tin oxide layers.

As a transparent touchpad, in one embodiment of the invention, a capacitive transparent touchpad may be provided which, for example, has a transparent film coated with the transparent, selectively structured indium tin oxide layer as a sensor film which is laminated onto a glass or acrylic plate. An alternating voltage applied in the corners of the sensor foil to the electrically conductive, selectively structured indium tin oxide layer generates a uniform electric field, so that a capacitive contact or input produces a small charge transport, which takes the form of a current at the corners is measured, with the resulting currents at the corners in direct proportion to the touch position. Since the capacitive input also acts on a laminated sensor foil through the glass or acrylic plate, the sensor foil can be arranged on a rear side of the glass or acrylic plate, which is advantageous for the robust use in a motor vehicle, since the latter is sensitive to mechanical damage Sensor film is protected from scratching, for example, fingernails through the glass or acrylic plate.

Alternatively, it is also possible to use a resistive transparent touchpad in which a resistance in the touch position, for example, between a transparent film and a glass or acrylic plate, each with facing electrically conductive transparent indium tin oxide layers changes upon contact of the conductive layers. For this purpose, the conductive coatings are spaced apart by micro-spacers from each other, and a DC voltage drops between opposite edges of a first conductive layer. At the touch position, the tension of both layers is the same because they touch each other there by the input. The second conductive layer at this point forms the connection to the outside, so that two voltages can be measured between the edge of the second conductive layer and the two edges of the first conductive layer. If the voltages are equal, the touch position is in the middle. The higher the voltage difference, the closer the touch position is to one of the edges of the first conductive layer. After reversing the functions by applying the DC voltage to the second conductive layer and tapping the voltages at the edges of the first conductive layer, the touch position of, for example, an icon can be accurately detected in X and Y directions without providing for selective patterning of the conductive layers. Since a minimal deformation of an outer film is required when using a resistive transparent touchpad, the mechanical robustness when inputting data compared to a capacitive transparent touchpad with external glass or acrylic plate is lower.

The arrangement of the DOE in a cavity between two concave mirrors has the advantage that the concave mirrors simultaneously form a housing and enable a suitable beam guidance. The beam guidance in the cavity between the two concave mirrors allows a very compact design of the display device. The DOE can be arranged either directly on the first concave mirror or in a central region of the cavity.

In one embodiment, the DOE is used transmissively. In this case, a transmissive use of the DOE is understood to mean that the light provided by the at least one light source impinges on and is incident on a first surface of the DOE and the light which serves to generate the holographic image rests on one of the first surface different second surface of the DOE emerges from this. In another embodiment, the DOE is used reflectively. In this case, a reflective use of the DOE means that the light provided by the at least one light source impinges on a first surface of the DOE and the light which serves to generate the holographic image exits the DOE on this first surface.

It is thus provided a display device which is also suitable for the selective display of complex information. This is in particular an advantage over conventional head-up displays because they are typically not cluttered or used too extensively.

In one embodiment, the diffractive optical element has dynamically controllable phase modulation cells. It is therefore a so-called dynamic DOE.

A dynamic DOE is understood here and below to mean a freely programmable, dynamically controllable optical element which shapes a light beam by diffraction on optical grating structures. A dynamic DOE has dynamically controllable phase modulation cells, also referred to as spatial light modulators (SLMs), which can be designed, for example, as liquid crystal elements or as micromechanically movable mirror elements. In this case, depending on the configuration of the phase modulation cells, the DOE can be operated in reflection or transmission.

This embodiment has the advantage that the dynamically controllable phase modulation cells enable the flexible representation of complex information and also moving images. It is thus created a freely programmable, flexible display.

In one embodiment, the diffractive optical element has controllable liquid crystal elements as phase modulation cells. The use of liquid crystal elements (LC) has the advantage that this technology for displaying dynamic holograms in real time is already well developed, so that even very complex holograms can be displayed in good quality.

There are, for example, dynamic DOE with micromechanically controllable Mirror elements can be used, in which the phase delay is adjusted by the fact that the mirrors are moved in the direction of light incidence.

In one embodiment, at least one light source is disposed within the cavity. This has the advantage that results in a very compact design, which allows easy installation of the display device. In addition, it is not necessary to provide further openings in the mirrors to bring radiation from the outside into the cavity.

Alternatively or additionally, however, at least one light source can also be arranged outside the cavity. This has the advantage of greater freedom in the arrangement of the individual components of the display device, in particular in the arrangement of light sources and DOE to each other.

As a light source can therefore also be used through the opening on the DOE incident daylight or ambient light.

In one embodiment, the display device has at least two light sources that emit radiation of different wavelengths. This embodiment has the advantage that multi-color holograms can be displayed.

In one embodiment, the display device has at least one first light source for emitting radiation having a wavelength λ _{r of} 650 nm ≦ λ _r ≦ 750 nm, a second light source emitting radiation having a wavelength λ _{g of} 490 nm ≦ λ _g ≦ 575 nm and a third light source for emitting radiation having a wavelength λ _{b of} 420 nm ≤ λ _b ≤ 490 nm.

In this embodiment, RGB (red-green-blue) laser systems or RGB LEDs can be used which achieve arbitrary colors by additive mixing of the radiation of different wavelengths generated by three light sources (red, green, blue).

The individual light sources can each be combined to form a module, wherein a color mixture takes place within the module. This allows almost any mixture of color for the holographic representation.

The use of different colored light sources also allows the display of multi-color holographic images in a time division multiplex method. For this purpose, the light sources are controlled independently of each other and it takes place for a first period, the lighting of a partial image of the holographic image encoding DOE in a first color, before for a second period, the another partial image encoding DOE is illuminated in a second color. In this way, a multi-color holographic image is displayed from at least two partial images of different colors. The time periods are chosen so short that the structure of individual sub-images is imperceptible to the human eye and gives the viewer in an averaged period of time the impression of a single, multicolored image.

According to one aspect of the invention, a vehicle is provided with a display device according to one of the described embodiments. The display device can be installed in particular in the area of a dashboard, a center console or a steering wheel. It can serve not only as a display, but also as an output and / or input device via the transparent touchpad on the opening of the second concave mirror. This has the advantage that the display device is further developed to the operating or actuating element by, for example, inputs by a user can be detected by "touching" certain areas of the transparent touchpad on the opening of the second concave mirror. In particular, the transparent touchpad on the opening of the second concave mirror can have internationally understandable icons which are semitransparent and are adapted in color and partial transparency of the holographic image. The transparent touchpad can also interact with an evaluation unit and an actuating unit. For example, the transparent touchpad of the display device may also be structurally separated from the evaluation unit and the actuation unit for vehicle components. In this case, the display device has corresponding interfaces. The transparent touchpad may preferably serve for controlling and activating an infotainment unit, an air-conditioning system, but also mechanical vehicle components such as adjustable seats, etc. using the operating unit. If the transparent touchpad capacitively detects an input by a user, the type of input can be concluded by an evaluation.

On the other hand, it is also possible to produce the representation of two- or three-dimensional actuation elements as a holographic image and / or to couple with the transparent touchpad, with the advantage that the holographic display device is flexible and adapted to the needs of the user when needed can. For example, freely programmable actuating elements are provided holographically, which goes far beyond the possibilities of the transparent, capacitively actuable touchpad of the display device. Depending on the condition of the vehicle or depending on the driving situation, another actuator can be displayed holographically. In addition, a pictured as a holographic image actuator is wear-free. It can also be determined, for example, whether a rotary switch is actuated in a clockwise or counterclockwise direction.

• – Beleuchtung eines in einem Hohlraum zwischen einem ersten Hohlspiegel und einem zweiten Hohlspiegel angeordneten diffraktiven optischen Elementes, das ein Hologramm bereitstellt, mittels zumindest einer Lichtquelle;
• – Leitung der von der zumindest einen Lichtquelle ausgehenden und von Phasenmodulationszellen des diffraktiven optischen Elementes modulierten Strahlung durch ein auf einer Öffnung des zweiten Hohlspiegels angeordneten transparenten Touchpad hindurch tritt unter Wiedergabe eines holografischen Bilds oberhalb des transparenten Touchpads innerhalb eines definierten Sichtbereichs.

According to another aspect of the invention, there is provided a computer program product which, when executed on a computing unit of a vehicle, instructs the computing unit to perform a method comprising the steps of:

• - Illumination of a arranged in a cavity between a first concave mirror and a second concave mirror diffractive optical element which provides a hologram, by means of at least one light source;
• - Conduction of the emanating from the at least one light source and modulated by phase modulation of the diffractive optical element radiation through a disposed on an opening of the second concave mirror transparent touchpad passes by reproducing a holographic image above the transparent touchpad within a defined field of view.

The method performed by the computer program has the advantage of providing a flexible holographic display with a transparent touchpad.

In one embodiment, a planar and / or three-dimensional holographic image is constructed from a plurality of holographic sub-images in a time-division multiplexing process.

For a three-dimensional representation, the holographic partial images can each be reproduced in one plane, the planes of the holographic partial images being spaced apart from one another. For this purpose, the three-dimensional image can be built up from individual layers (layers) arranged parallel to one another, for example, each having a specific spacing from one another and thus also from the DOE. By appropriate control and illumination of the DOE, the individual partial images are each generated for a short period of time, wherein the human eye perceives the three-dimensional image on average. In this way, it is possible, even with a relatively simple appearance and with limited computational effort, to represent three-dimensional structures, for example three-dimensional actuators. The use of a time division multiplex method for generating three-dimensional holographic images is disclosed in US Pat US 7,936,489 B2 described, which is incorporated herein by reference.

In one embodiment, the diffractive optical element is time-multiplexed with different wavelength radiation, and a multi-color holographic image is built up from a plurality of holographic fields, the holographic fields having different colors. Such a multi-color holographic image may be two- or three-dimensional.

In particular, an RGB laser or RGB diodes can be used for this purpose. The color multiplexing allows the representation of a colored holographic image. The mixture of the components of different colors takes place temporally by producing holographic partial images of different colors at different times.

In one embodiment, an animated representation for explaining vehicle functions is reproduced as a holographic image. For example, a so-called avatar, i. H. a virtual person, who explains vehicle functions or demonstrates their use. Furthermore, an animated image of the vehicle itself can also be displayed to explain vehicle functions. In this case, an acoustic support of the presentation can be provided. This has the advantage that information related to the user of vehicle functions can be presented in a catchy, responsive manner.

According to a further aspect of the invention, a computer-readable medium is specified, on which a computer program product according to one of said embodiments is stored.

• – Mittel zur Beleuchtung eines in einem Hohlraum zwischen einem ersten Hohlspiegel und einem zweiten Hohlspiegel angeordneten diffraktiven optischen Elementes, das ein Hologramm bereitstellt, mittels zumindest einer Lichtquelle;
• – Mittel zur Leitung der von der zumindest einen Lichtquelle ausgehenden und von Phasenmodulationszellen des diffraktiven optischen Elementes modulierten Strahlung durch ein auf einer Öffnung des zweiten Hohlspiegels angeordnetes transparentes Touchpad hindurch unter Wiedergabe eines holografischen Bilds oberhalb des transparenten Touchpads innerhalb eines definierten Sichtbereichs.

According to another aspect of the invention, there is provided an apparatus for displaying a holographic image

• - means for illuminating a arranged in a cavity between a first concave mirror and a second concave mirror diffractive optical element, which provides a hologram, by means of at least one light source;
• Means for guiding the radiation emanating from the at least one light source and modulated by phase modulation cells of the diffractive optical element through a transparent touchpad arranged on an opening of the second concave mirror, reproducing a holographic image above the transparent touchpad within a defined viewing area.

The device thus provides a flexibly usable holographic display in cooperation with a transparent touchpad.

In one embodiment, the device comprises means for constructing a plane and / or Three-dimensional holographic image of several holographic fields in a time division multiplex method. This has the advantage that it is possible to holographically represent three-dimensional structures, for example three-dimensional actuators, even with relatively simple optics and with limited computational effort.

In one embodiment, the device comprises means for illuminating the diffractive optical element in a time-division multiplexing process with radiation of different wavelengths and for constructing a multi-color holographic image from a plurality of holographic partial images, the holographic partial images having different colors. This has the advantage that a multi-colored representation of holographic images is possible in a technically simple manner.

In one embodiment, the device comprises means for rendering an animated representation for explaining vehicle functions as a holographic image. This has the advantage that information related to the user of vehicle functions can be presented in a catchy, responsive manner.

Embodiments of the invention will now be described with reference to the accompanying figures.

1 schematically shows a display device according to a first embodiment of the invention;

2 schematically shows a display device according to a second embodiment of the invention;

3 schematically shows a display device according to a third embodiment of the invention and

4 schematically shows a vehicle with a display device according to an embodiment of the invention.

1 shows a display device 1 according to a first embodiment of the invention. The display device 1 has a first concave mirror 2 with a mirror surface 3 and a second concave mirror 4 with a mirror surface 5 on. Through the two concave mirrors 2 . 4 is a convex cavity 6 spanned on all sides by the concave mirrors 2 . 4 is limited. The mirror surfaces 3 . 5 clothe the cavity 6 inside out, leaving the cavity 6 inside is almost completely mirrored.

Inside the cavity 6 is a diffractive optical element (DOE) 7 arranged, which is substantially flat with a first main surface 8th and one of these opposing second major surfaces 9 is trained. The first main surface 8th is at the mirror surface 3 of the first concave mirror 2 arranged and the second surface 9 is to the middle of the cavity 6 directed. At the in 1 The first embodiment shown is the DOE 7 on the mirror surface 3 of the first concave mirror 2 opposite one of a transparent touchpad 30 covered opening 11 and on the edge of the cavity 6 arranged.

The DOE 7 has a plurality of not shown phase modulation cells (spatial light modulators) for generating a Hohlgrammbildes on. These are inside the cavity 6 light sources 10 arranged, which may be formed in particular as LED or as laser diodes and illuminate the DOE. In 1 are two such light sources 10 shown. However, there may be more or less light sources 10 be provided. arrows 17 schematically show the beam path of the light sources 10 outgoing light.

In the in 1 The embodiment shown is the DOE 7 operated in reflection. Light of the light sources 10 meets on the second main surface 9 and leaves the DOE 7 after the diffraction also on this again. In this particular example, the diffracted light hits the opposite mirror surface 5 on, will be on the first mirror surface 3 bent and then leaves the cavity 6 through the transparent touchpad 30 that on the opening 11 in the second concave mirror 4 is arranged, with the transparent touchpad 30 in the manner of a window the opening 11 covered. Above the transparent touchpad 30 becomes the holographic picture 13 within a defined, for example, spherical area, for example, imaged on the inner surface of a windshield.

The shape and curvature of the concave mirror 2 . 4 are adapted to the desired beam path, they are in particular the shape and position of the DOE 7 , from the position of the light sources 10 and from the position of the transparent touchpad 30 covered opening 11 dependent.

2 shows a display device 1 according to a second embodiment. This is different from the one in 1 shown first by the fact that the DOE 7 is operated in transmission. The light source 10 is therefore arranged to be the first major surface 8th of the DOE 7 illuminated. In the in 2 example shown, the light of the light source 10 from the first main surface 8th through the DOE 7 to the second main surface 9 and is at the opposite second mirror surface 5 bent, from there to the first mirror surface 3 and from the first mirror surface 3 through the transparent touchpad 30 on the opening 11 reflected. In the in 2 the embodiment shown is the light source 10 between the first concave mirror 2 and the DOE 7 arranged so that the light is directly on the first main surface 8th occurs. However, the light source can also be arranged such that its light only after a reflection on the mirror surface 3 on the first main surface 8th meets.

At the in 2 shown second embodiment is the DOE 7 compared to the first embodiment, some of the mirror surface 3 of the first concave mirror 2 in the direction of the opening 11 with the transparent touchpad 30 offset and thus more to the center of the cavity 6 staggered. This makes it possible to use the light source 10 between the mirror surface 3 and the DOE 7 to arrange.

3 shows a display device 1 according to a third embodiment. This differs from the ones in the 1 and 2 shown by the fact that the light sources 10 outside the cavity 6 are arranged. One of the concave mirrors 2 . 4 , in this case the second concave mirror 4 , then has more openings 14 with translucent covers 15 on, through which the light enters the cavity 6 and on the DOE 7 arrives.

4 schematically shows a vehicle 18 with a display device 1 according to an embodiment of the invention. Shown is the view into the cockpit 19 with a dashboard 20 of the vehicle 18 , The dashboard 20 In addition to the conventional monitoring instruments such as speed, engine speed, coolant temperature, tank level, a screen 16 have holographically reproduces optional recordings of a rear-view camera and or a front camera as parking aids.

On a center console 12 is in the cockpit 19 a display device 1 arranged according to an embodiment of the invention. To control the display device 1 , in particular the light sources and the phase modulation cells, this is via a signal line 25 with a computing unit 21 connected, in turn, via another signal line 29 Data with an evaluation unit 22 can exchange.

In this embodiment, the display device 1 on the opening of the second concave mirror, a transparent touchpad 30 as a capacitive input element, via which an actuating element of an actuating unit 23 for a vehicle component 24 For example, for an infotainment system, a navigation system, air conditioning or an adjustable seat, can be activated. The transparent touchpad is used 30 the capture of input from a user. The transparent touchpad 30 is over another signal line 26 with the evaluation unit 22 connected, which is also part of the arithmetic unit 21 can be. The evaluation unit 22 recognizes and evaluates through the transparent touchpad 30 detected input by the user and assigns it an actuation of a vehicle component 24 to. The evaluation unit 22 is to cause actuation by a signal line 27 with an operating unit 23 the vehicle component 24 connected. About a connection 28 depending on the vehicle component 24 a signal line, a mechanical connection or another type of connection, causes the actuator unit 23 the actuation of the vehicle component 24 ,

Although at least one exemplary embodiment has been shown in the foregoing description, various changes and modifications may be made. The above embodiments are merely examples and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing description provides those skilled in the art with a plan for practicing at least one example embodiment, and wherein numerous changes can be made in the operation and arrangement of elements described in an exemplary embodiment without departing from the scope of the appended claims and their legal equivalents ,

LIST OF REFERENCE NUMBERS

1

display device

2

first concave mirror

3

mirror surface

4

second concave mirror

5

mirror surface

6

cavity

7

diffractive optical element (DOE)

8th

first main surface

9

second main surface

10

light source

11

opening

12

center console

13

holographic picture

14

opening

15

cover

16

holographic screen

17

arrow

18

vehicle

19

cockpit

20

dashboard

21

computer unit

22

evaluation

23

operating unit

24

vehicle component

25

signal line

26

signal line

27

signal line

28

connection

29

signal line

30

transparent touchpad

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1956413 A2 [0002]
• US 7936489 B2 [0033]

Claims (15)

Display device ( 1 ), comprising: - at least one first concave mirror ( 2 ) and a second concave mirror ( 4 ), wherein the second concave mirror ( 4 ) at least one opening ( 11 ) having; - one through the two concave mirrors ( 2 . 4 ) spanned convex cavity ( 6 ); - one in the cavity ( 6 ) arranged diffractive optical element ( 7 ) with a number of optical phase modulation cells, wherein the diffractive optical element ( 7 ) provides a hologram; At least one light source ( 10 ) for illuminating the phase modulation cells of the diffractive optical element ( 7 ), and - a transparent touchpad ( 30 ), which has at least one opening ( 11 ) and provides an input of data, wherein the diffractive optical element ( 7 ) in the cavity ( 6 ) is arranged that of the at least one light source ( 10 ) outgoing radiation is modulated by the phase modulation cells, by the transparent touchpad ( 30 ) on the opening ( 11 ) and above the transparent touchpad ( 30 ) within a defined field of view a holographic image ( 13 ). Display device ( 1 ) according to claim 1, wherein the transparent touchpad ( 30 ) a capacitive transparent touchpad ( 30 ). Display device ( 1 ) according to claim 1, wherein the transparent touchpad ( 30 ) a resistive transparent touchpad ( 30 ). Display device ( 1 ) according to one of claims 1 to 3, wherein the defined field of view is spherical. Display device ( 1 ) according to one of claims 1 to 4, wherein the diffractive optical element ( 7 ) has dynamically controllable phase modulation cells. Display device ( 1 ) according to one of claims 1 to 5, wherein at least one light source ( 10 ) within the cavity ( 6 ) is arranged. Display device ( 1 ) according to one of claims 1 to 6, wherein at least one light source ( 10 ) outside the cavity ( 6 ) is arranged. Display device ( 1 ) according to one of claims 1 to 7, wherein the display device ( 1 ) at least one first light source ( 10 ) for emitting radiation having a wavelength λ _r with 650 nm ≦ λ _r ≦ 750 nm, a second light source ( 10 ) for emitting radiation having a wavelength λ _{g of} 490 nm ≦ λ _g ≦ 575 nm and a third light source ( 10 ) for emitting radiation having a wavelength λ _b with 420 nm ≤ λ _b ≤ 490 nm. Display device ( 1 ) according to claim 8, wherein the light sources ( 10 ) are independently controllable. Vehicle ( 18 ) with a display device ( 1 ) according to one of claims 1 to 9. Vehicle ( 18 ) according to claim 10, wherein the vehicle ( 18 ) further comprises: - at least one transparent touchpad ( 30 ), which has at least one opening ( 11 ) and provides input of data by a user; - an evaluation unit ( 22 ) for evaluating the input and - an actuating unit ( 23 ) for actuating a vehicle component ( 24 ) depending on the input by the user. Computer program product that, when stored on a computer unit ( 21 ) of a vehicle ( 18 ) is executed, the arithmetic unit ( 21 ) to perform a method comprising the steps of: - illuminating one in a cavity ( 6 ) between a first concave mirror ( 2 ) and a second concave mirror ( 4 ) arranged diffractive optical element ( 7 ), which provides a hologram, by means of at least one light source ( 10 ); - Conduction of the at least one light source ( 10 ) and phase modulation cells of the diffractive optical element ( 7 ) modulated radiation through an on an opening ( 11 ) of the second concave mirror ( 4 ) arranged transparent touchpad ( 30 ), reproducing a holographic image ( 13 ) above the transparent touchpad ( 30 ) within a defined field of view. Computer program product according to claim 12, wherein in a time-division multiplexing method a planar and / or three-dimensional holographic image ( 13 ) is constructed from several holographic fields. The computer program product of claim 13, wherein the holographic fields are each rendered in a plane, and wherein the planes of the holographic fields are spaced apart. Computer program product according to one of claims 12 to 14, wherein the diffractive optical element ( 7 ) is illuminated in a time division multiplexing method with radiation of different wavelengths and a multicolored holographic image ( 13 ) is built up from several holographic partial images, wherein the holographic fields have different colors.

Images