DE102013011253A1 - Display device, vehicle with a display device and computer program product - Google Patents

Abstract

Display device (1) comprising: - at least one first concave mirror (2) and one second concave mirror (4), the second concave mirror (4) having at least one opening (11); - A through the two concave mirrors (2, 4) spanned convex cavity (6); A diffractive optical element (7) arranged in the cavity (6) with a number of optical phase modulation cells, the diffractive optical element (7) providing a hologram; At least one light source (10) for illuminating the phase modulation cells of the diffractive optical element (7), wherein the diffractive optical element (7) is arranged in the cavity (6) such that radiation emitted by the at least one light source (10) passes through the Phase modulation cells is modulated, emerges through the opening (11) in the second concave mirror (4) and above the opening (11) within a defined field of view an image (13) reproduces.

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 element 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, especially in a vehicle, in terms of a flexible, user-related use. 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 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 opening in the second concave mirror exit and above the opening within a defined field of view reproduces a holographic image.

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 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.

The arrangement of the DOE and optionally also the light sources in the cavity formed by the two concave mirrors creates a very compact display device, at the opening of which the hologram is represented. Another remote projection screen 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 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.

For example, it is also possible to use dynamic DOEs with micromechanically controllable mirror elements, in which the phase delay is set by displacing the mirrors in the direction of the 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.

In one embodiment, the holographic image represents at least one actuator and / or compass and / or animated display and / or touchscreen. This has the advantage that the display device can be used to assist a driver of a vehicle.

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.

In one embodiment, the holographic image reproduces at least one actuating element of the vehicle, in particular at least one switching element of the vehicle. For this purpose, the vehicle with the display device further comprises a sensor for detecting an input by a user in the field of view of the holographic image, an evaluation unit for evaluating the input and an actuating unit for actuating a vehicle component depending on the input by the user.

This has the advantage that the display device is developed to the operating or actuating element, for example, by input of a user by "touching" certain areas of the holographic image can be detected by the sensor. In this case, in particular the sensor, if appropriate also the evaluation unit and the actuating unit can be structurally integrated into the display device. For example, the sensor may be disposed within the cavity. In particular, the evaluation unit and the actuating unit can also be structurally separated from the display device. Then, the display device has corresponding interfaces.

As a sensor, for example, a camera can be used, in particular an optical or infrared camera. Alternatively, a proximity sensor or an ultrasonic sensor may also be used to detect an input of a user in the field of view of the holographic image.

The holographic image in this embodiment, for example, take on the role of a touch screen and the user represent a series of panels that can select this with his finger. This can be a two-dimensional control panel. However, it is also possible to reproduce three-dimensional actuating elements as holographic images, for example toggle switches, rotary switches or joysticks. The actuating element can serve, for example, for actuating an infotainment unit, an air-conditioning system, but also mechanical vehicle components such as, for example, adjustable seats.

Likewise, for example, a compass can be displayed or another representation can be reproduced to assist the user in the navigation.

The sensor may be located inside or outside the cavity. When the sensor detects the operation of the operating member by a user, it can be concluded by an evaluation on the type of operation. For example, it can be determined whether a rotary switch is operated clockwise or counterclockwise.

The representation of two- or three-dimensional actuators as a holographic image has the advantage that it is flexible and can be changed if necessary. There are thus provided freely programmable actuators. Depending on the state of the vehicle or depending on the driving situation, another actuator can be displayed. In addition, a pictured as a holographic image actuator is wear-free.

• – 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 eine Öffnung des zweiten Hohlspiegels unter Wiedergabe eines holografischen Bilds oberhalb der Öffnung 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 cells of the diffractive optical element radiation through an opening of the second concave mirror to reproduce a holographic image above the opening within a defined field of view.

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

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 the generation Three-dimensional holographic images is in the 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 eine Öffnung des zweiten Hohlspiegels unter Wiedergabe eines holografischen Bilds oberhalb der Öffnung 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 an opening of the second concave mirror with reproduction of a holographic image above the opening within a defined field of view.

The device thus provides a flexible usable holographic display.

In one embodiment, the apparatus has means for constructing a planar and / or three-dimensional holographic image from a plurality of holographic sub-images in a time-division multiplexing method. This has the advantage that it is possible to present 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;

4 schematically shows a display device according to a fourth embodiment of the invention and

5 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 dress that 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 an opening 11 in the second concave mirror 4 and on the edge of the cavity 6 arranged. The opening 11 is centered in the concave mirror 4 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 opening 11 in the second concave mirror 4 in the style of a window with a cover 12 is provided. Above the opening 11 becomes the holographic picture 13 imaged within a defined, for example, spherical, area.

The shape and curvature of the concave mirror 2 . 4 are adapted to the desired beam path, they are particularly dependent on the shape and position of the DOE 7 , from the position of the light sources 10 and from the position of the opening 11 ,

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 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 offset or spaced 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.

An arrangement of the light sources 10 outside the cavity 6 can in particular also in a DOE operated in transmission, as in 2 is shown to be provided.

4 shows a display device 1 according to a fourth embodiment. This differs from that shown in the other figures in that a sensor 16 to observe the field of view of the holographic image 13 is provided. The sensor 16 has the task to capture a user input. The sensor 16 is in the in 4 shown embodiment partially within the cavity 6 arranged and formed in the embodiment shown as an infrared camera. However, the sensor can also be arranged outside the cavity.

Such a sensor 16 may also be in an arrangement with outside the cavity 6 arranged light sources 10 as in 3 be provided shown.

5 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 of the vehicle 18 ,

On the dashboard 20 is 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 this embodiment, the display device is 1 as an actuating element, in particular as a switch, for a vehicle component 24 For example, for an infotainment system, a navigation system, an air conditioner or an adjustable seat trained. For this purpose, the display device 1 a sensor 16 for detecting inputs of a user who is formed as an infrared camera. The sensor 16 is through a signal line 26 with an evaluation unit 22 connected, which is also part of the arithmetic unit 21 can be. The evaluation unit 22 recognizes and evaluates the through the sensor 16 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

cover

13

holographic picture

14

opening

15

cover

16

sensor

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

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 [0037]

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 an image; At least one light source ( 10 ) for illuminating the phase modulation cells of the diffractive optical element ( 7 ), 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, through the opening ( 11 ) in the second concave mirror ( 4 ) and above the opening ( 11 ) within a defined field of view an image ( 13 ). Display device ( 1 ) according to claim 1, wherein the defined field of vision is spherical. Display device ( 1 ) according to claim 1 or 2, wherein the diffractive optical element ( 7 ) has dynamically controllable phase modulation cells. Display device ( 1 ) according to one of claims 1 to 3, wherein at least one light source ( 10 ) within the cavity ( 6 ) is arranged. Display device ( 1 ) according to one of claims 1 to 4, wherein at least one light source ( 10 ) outside the cavity ( 6 ) is arranged. Display device ( 1 ) according to one of claims 1 to 5, 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 6, wherein the light sources ( 10 ) are independently controllable. Display device ( 1 ) according to one of claims 1 to 7, wherein the image ( 13 ) reproduces at least one actuating element and / or a compass and / or an animated display and / or a touch screen. Vehicle ( 18 ) with a display device ( 1 ) according to one of claims 1 to 8. Vehicle ( 18 ) according to claim 9, wherein the holographic image ( 13 ) at least one actuating element of the vehicle ( 18 ), in particular at least one switching element and / or a touchscreen reproduces and wherein the vehicle ( 18 ) further comprises: - at least one sensor ( 16 ) for capturing an input by a user in the field of view of the image ( 13 ); - 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 opening ( 11 ) of the second concave mirror ( 4 ) playing a picture ( 13 ) above the opening ( 11 ) within a defined field of view. Computer program product according to claim 11, wherein in a time-division multiplexing method a planar and / or three-dimensional image ( 13 ) is constructed from several sub-images. The computer program product of claim 12, wherein the sub-images are each rendered in a plane and wherein the planes of the sub-images are spaced apart. Computer program product according to one of claims 11 to 13, wherein the diffractive optical element ( 7 ) is time-multiplexed with different wavelength radiation and a multicolor image ( 13 ) is made up of a plurality of partial images, wherein the partial images have different colors. Computer program product according to one of claims 11 to 14, wherein as image ( 13 ) At least one actuating element and / or a Compass and / or an animated display and / or a touch screen is played.

Images