DE202014003241U1 - Holographic display device, vehicle with holographic display device and computer program product - Google Patents

Abstract

A holographic display device comprising; A housing with an opening (4), a transparent cover of the opening (4), a hologram foil (5) with a static optical interference grid within the housing (2) on an underside (6) of the transparent cover (3), A transmissive programmable diffractive optical element (7) with a number of optical phase modulation cells, which is arranged opposite the opening (4) and below the hologram foil (5) in the housing (2), at least one light source (8) below of the transmissive programmable diffractive optical element (7) is arranged.

Description

A holographic display device and a vehicle with a holographic display device as well as a computer program product are described.

From the DE 10 2007 007 162 A1 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, especially in a vehicle, in terms of a flexible, user-related use. In particular, a holographic 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 holographic display device and a computer program product.

A first aspect of the invention relates to a holographic display device having a housing with an opening. The opening has a transparent cover, on the underside of which a hologram foil with a static optical interference grid is arranged inside the housing. Opposite to the opening and below the hologram foil is in the housing a transmissive programmable diffractive optical element, hereinafter called DOE, arranged with a number of optical phase modulation cells. Furthermore, at least one light source is arranged below the transmissive programmable DOE within the housing.

The transmissive programmable 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 holographic display device allows information to be displayed as a holographic image above the opening in the housing. 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.

In a further embodiment of the invention, the at least one light source and the transmissive programmable DOE are arranged below the hologram film in the housing in such a way that the radiation emanating from the at least one light source has a phase modulation through the phase modulation cells after passing through the transmissive programmable DOE. After the radiation has passed through the static optical interference grating network of the holographic film arranged above it, the radiation has a holographic treatment. Due to the phase modulation and the holographic processing of the radiation, the display device can have a programmable virtual holographic image above the opening and in a defined viewing area.

Accordingly, the holographic display device can also be installed as a self-contained module in an environment that may have further display devices, for example in a dashboard of a vehicle.

The arrangement of the transmissive programmable DOE in the housing between the at least one light source and the hologram foil also has the advantage that the beam guidance in the housing allows a very compact design of the display device. The transmissive programmable DOE is thus arranged in a central region of the housing.

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 transmissive programmable DOE exits therefrom and is phase modulated, but has not holographically processed or reconstructed. This holographic processing takes place with the passage of the radiation through the interference grating of the hologram film, which is also transmissive, so that the phase-modulated radiation between the only a few nanometers wide blackened lines of the interference grating network, which are arranged at a distance of a few 10 nanometers to each other, can pass and due to the interference grid allows a virtual holographic image in a field of view above the opening and thus outside of the housing.

In one embodiment, the DOE has dynamically controllable phase modulation cells. 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 micromechanically movable micromirror elements. In this case, the DOE can be operated by the transmissive design of the phase modulation cells in 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 option.

In one embodiment, the transmissive programmable DOE has controllable liquid crystal elements as phase modulation cells. The use of liquid crystal (IC) elements 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 if a suitable hologram foil is provided which holographically processes the phase-modulated beams transmissive through, for example, liquid crystal elements.

For example, it is also possible to use dynamic DOEs with micro-mechanically controllable micromirror 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 housing beneath the transmissive programmable DOE. 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 housing to guide radiation from the outside into the housing.

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 a further embodiment, the display device has at least one first light source for emitting radiation in a first wavelength range λ _r with 650 nm ≦ λ _r ≦ 750 nm, a second light source for emitting radiation in a second wavelength range λ _g with 490 nm ≦ λ _g ≤ 575 nm and a third light source for emitting radiation in a third wavelength range λ _b with 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 is done for a first period, the lighting of a partial image of the holographic image coding DOE in a first color, before for a second period, the same but another field encoding DOE is illuminated in a second color. In this way, a multi-color holographic image from at least two partial images of different colors can be displayed. 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 holographic display device according to one of the described embodiments. The holographic display device can be installed in particular in the region 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 a separate touchpad that interacts with a data processing device that is composed of an electronic control unit or a microprocessor unit. This has the advantage that the display device is developed to the operating or actuating element by, for example, inputs by a user can be detected by "touching" certain areas of the separate touchpad.

In this case, in particular a transparent touchpad can also have internationally understandable icons or pictograms on the opening of the housing, which are semitransparent and are adapted in coloration and partial transparency of the holographic image. Also, such a transparent touchpad can interact with an electronic data processing device and a control unit. For example, the transparent touchpad of the display device may also be structurally separate from data processing devices and control units for vehicle components. In this case, the holographic display device has corresponding interfaces.

Both the separate and the transparent touchpad mounted on the opening of the housing can simultaneously serve to control and activate an infotainment unit, an air conditioning system, but also mechanical vehicle components such as adjustable seats, etc. using the control unit. If both the separate and 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 generate the representation of two- or three-dimensional actuation elements as a holographic image and / or to couple them to a touchpad, which has the advantage that the holographic display device is flexible and can be adapted to the needs of the user as needed. For example, freely programmable actuating elements are provided holographically, which goes far beyond the possibilities of the transparent, capacitively actuable touchpad of such a display device. Depending on the condition of the vehicle or depending on the driving situation, another actuating element 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 Gehäuse zwischen zumindest einer Lichtquelle und einer Hologrammfolie angeordneten transmissiven programmierbaren diffraktiven optischen Elements mit einer Anzahl von optischen Phasenmodulationszellen, mittels der Lichtquelle;
• – Aufbereiten der von der zumindest einen Lichtquelle ausgehenden und beim Durchtritt durch die Phasenmodulationszellen des transmissiven programmierbaren diffraktiven optischen Elements phasenmodulierten Strahlung durch ein statisches optisches Interferenzgitternetz der Hologrammfolie zu einem virtuellen holografischen Bild innerhalb eines definierten Sichtbereichs oberhalb einer Öffnung des Gehäuses.

According to another aspect of the invention, there is provided a computer program product which, when executed on an electronic data processing device of a vehicle, instructs the electronic data processing device to perform a method comprising the steps of:

• - Illumination of a arranged in a housing between at least one light source and a hologram foil transmissive programmable diffractive optical element having a number of optical phase modulation cells, by means of the light source;
• Processing the radiation emanating from the at least one light source and phase-modulating through the phase modulation cells of the transmissive programmable diffractive optical element through a static optical interference grid of the hologram film to a virtual holographic image within a defined field of view above an opening of the housing.

The method performed by the computer program product 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 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 transmissive programmable DOE is time multiplexed using a wavelength division multiplexed time multiplexer and a multicolor holographic image is formed from a plurality of holographic fields upon passage of the radiation and phase modulation by the transmissive programmable DOE and holographic reconstruction by the hologram film constructed, wherein the holographic fields have 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 mix of different colors Components take place temporally by producing holographic partial images in 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 Gehäuse zwischen zumindest einer Lichtquelle und einer Hologrammfolie angeordneten transmissiven programmierbaren diffraktiven optischen Elements mit einer Anzahl von optischen Phasenmodulationszellen, mittels der Lichtquelle, und
• – Mittel zum Aufbereiten der von der zumindest einen Lichtquelle ausgehenden und beim Durchtritt durch die Phasenmodulationszellen des transmissiven programmierbaren diffraktiven optischen Elements phasenmodulierten Strahlung durch ein statisches optisches Interferenzgitternetz der Hologrammfolie zu einem virtuellen holografischen Bild innerhalb eines definierten Sichtbereichs oberhalb einer Öffnung des Gehäuses.

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

• Means for illuminating a transmissive programmable diffractive optical element arranged in a housing between at least one light source and a hologram foil with a number of optical phase modulation cells, by means of the light source, and
• Means for conditioning the radiation emanating from the at least one light source and phase-modulated as it passes through the phase modulation cells of the transmissive programmable diffractive optical element through a static optical interference grating of the hologram film to a virtual holographic image within a defined field of view above an opening of the housing.

The device thus provides a flexible holographic display.

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

1 shows a basic arrangement of components of a holographic display device according to a first embodiment of the invention;

2 shows a schematic representation of a holographic display device in a vehicle.

1 shows a basic arrangement of components of a holographic display device 1 according to a first embodiment of the invention. The holographic display device 1 has a housing 2 with an opening 4 on. The opening 4 has a transparent cover 3 , on the bottom of which inside the case 2 a hologram foil 5 is arranged with a static optical interference grid. Opposite to the opening 4 and below the hologram foil 5 is in the case 2 a transmissive programmable diffractive optical element 7 (also called DOE) arranged with a number of optical phase modulation cells. Furthermore, inside the case 4 below the transmissive programmable DOE 7 three light sources 8th . 9 and 10 arranged the light of different wavelength in a light guide plate 22 inject.

The light sources 8th . 9 and 10 Light time multiplexes in different wavelength ranges across the lightguide plate 22 the transmissive programmable DOE 7 , where the first light source 8th for emitting radiation in a first red wavelength range λ _r with 650 nm ≦ λ _r ≦ 750 nm, the second light source 9 for emitting radiation in a second green wavelength range λ _g with 490 nm ≦ λ _g ≦ 575 nm and the third light source 10 for emitting radiation in a third blue wavelength range λ _b with 420 nm ≤ λ _b ≤ 490 nm are provided. In this case, the differently colored light after mutiplextem passage through the transmissive programmable DOE 7 with phase shift of the radiation and after holographic processing during the passage of the phase-shifted radiation through the hologram film arranged above it 5 a multicolored virtual holographic image 13 in a field of vision 12 , what in 2 is shown outside the opening 4 of the housing 2 to be provided.

The transmissive programmable DOE 7 has a plurality of not shown phase modulation cells (spatial light modulators) for phase modulation of the multiplexed radiation. These are inside the case 2 the light sources 8th . 9 and 10 arranged, which may be formed in particular as LED or as laser diodes and the transmissive programmable DOE 7 illuminate.

In the in 1 In the embodiment shown, the transmissive programmable DOE 7 operated in transmission. Light of the light sources 8th . 9 and 10 meets over the light guide plate 22 on a bottom 16 and leaves the transmissive programmable DOE 7 after phase modulation also on the top 17 of the transmissive programmable DOE 7 , In this example, the phase-modulated light shines through the hologram foil arranged above it 5 and holographically by means of the interference grating network of the hologram foil 5 prepared and passes through the on the hologram foil 5 supporting transparent cover 3 out of the opening 4 out of the case 2 out. The emerging phase-modulated and holographically processed radiation can, as the following 2 points to a windshield 21 a vehicle 20 be directed and in the field of vision 12 a driver 18 a virtual holographic picture 13 let appear.

2 shows a schematic representation of a holographic display device 1 in a vehicle 20 , Components of 2 with the same functions as in 1 are denoted by like reference numerals and will not be discussed separately.

The holographic display device 1 indicates in addition to the in 1 components shown a control unit 15 on that over a time multiplexer 19 in the case 2 arranged three light sources 8th . 9 and 10 the wavelength ranges RGB (red, green and blue) offset in time via a time multiplexer 19 turns on so that three fields from the transmissive programmable DOE placed above it 7 phase modulated, and by means of the above the transmissive programmable DOE 7 in the case 2 arranged hologram foil 5 with static interference grid to a multicolor virtual holographic image 13 holographically processed or reconstructed.

The control unit 14 simultaneously controls a data processing device 14 , the simultaneously stored partial images in the transmissive programmable DOE 7 over the time multiplexer 19 for multiplexing the phase modulation. The phase-modulated and holographically processed partial images are combined with the rays 11 the light sources 8th . 9 and 10 on a windshield 21 of the vehicle 20 in a viewing area 12 the driver 18 to a virtual, colored, holographic picture 13 reconstructed from the three partial images.

In 2 are the additional components of the holographic display 1 outside the case 2 however, these may also be disposed within the housing to provide a compact device for installation in a vehicle, for example.

The driver accepts the reconstructed holographic image in the illustrated embodiment 2 as in the area of the windshield 21 or behind the windshield 21 true. The perceived distance of the reconstructed hologram is predetermined by the holographic image and can by means of control unit 15 and data processing device 14 be varied. This variation also takes into account the optical path of the lightwave fields through the vehicle interior. In particular, the hologram becomes the spatial surface contour of the windshield 21 and optionally also the thickness of the windshield 21 or the thickness profile of the windshield 21 customized. In this way, the driver sees an undistorted virtual display.

The adaptation and variation is achieved without adaptation of optical elements such as mirrors, lenses or other optical projection systems. It is only sufficiently different adapted hologram templates in the transmissive programmable DOE 7 with which the transmissive programmable DOE 7 via the data processing device 14 is controlled. Performed adjustments, for example by means of test images, can be stored as vehicle parameters in the data processing device, so that these vehicle parameters can be taken into account in the calculation and provision of holograms.

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 ,

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

• DE 102007007162 A1 [0002]
• US 7936489 B2 [0029]

Claims (14)

A holographic display device comprising; A housing with an opening ( 4 ), - a transparent cover of the opening ( 4 ), - a hologram foil ( 5 ) with a static optical interference grid within the housing ( 2 ) on a lower side ( 6 ) of the transparent cover ( 3 ), - a transmissive programmable diffractive optical element ( 7 ) with a number of optical phase modulation cells, which are opposite to the opening ( 4 ) and below the hologram foil ( 5 ) in the housing ( 2 ), - at least one light source ( 8th ) below the transmissive programmable diffractive optical element ( 7 ) is arranged. Display device according to claim 1, wherein the light source ( 8th ) and the transmissive programmable diffractive optical element ( 7 ) so below the hologram foil ( 5 ) in the housing ( 2 ) are arranged such that the at least one light source ( 8th ) emanating radiation through the phase modulation cells after passing through the transmissive programmable diffractive optical element ( 7 ) a phase modulation and after passing through the static optical interference grid of the holographic film ( 5 ) has a holographic processing, and wherein by phase modulation and holographic treatment of the radiation ( 11 ) above the opening ( 4 ) and in a defined field of vision ( 12 ) the holographic display device ( 1 ) a programmable virtual holographic image ( 13 ) having. Display device according to claim 1 or 2, wherein the defined field of vision ( 12 ) is spherical. Display device according to any one of the preceding claims, wherein the transmissive programmable diffractive optical element ( 7 ) has dynamically controllable phase modulation cells. Display device according to one of the preceding claims, wherein the at least one light source ( 8th ) is a laser diode. A display device according to claim 5, wherein the laser diode emits coherent light having a coherence length suitable for holographic image reproduction. Display device according to any preceding claim, wherein the holographic display device ( 1 ) at least a first light source for emitting radiation in a wavelength range λ _r with 650 nm ≤ λ _r ≤ 750 nm, a second light source for emitting radiation in a wavelength range λ _g with 490 nm ≤ λ ₉ ≤ 575 nm and a third light source for Emission of radiation in a wavelength range λ _b with 420 nm ≤ λ _b ≤ 490 nm. Display device according to claim 7, wherein the radiations of the light sources ( 8th . 9 . 10 ) are independently controllable. Vehicle with a holographic display device ( 1 ) according to any one of the preceding claims. Vehicle according to claim 9, wherein the vehicle ( 20 ) further comprises: - an electronic data processing device ( 14 ) and - a control unit ( 15 ) - a time multiplexer ( 19 ). Computer program product which, when stored on an electronic data processing device ( 14 ) of a vehicle ( 20 ), the electronic data processing device ( 14 ) to carry out a method comprising the steps of: - illuminating one in a housing ( 2 ) between at least one light source ( 8th ) and a hologram foil ( 5 ) arranged transmissive programmable diffractive optical element ( 7 ) with a number of optical phase modulation cells, by means of the light source ( 8th ); Preparing the at least one light source ( 8th ) and when passing through the phase modulation cells of the transmissive programmable diffractive optical element ( 7 ) phase-modulated radiation through a static optical interference grating network of the hologram film ( 5 ) to a virtual holographic image within a defined field of view ( 12 ) above an opening ( 4 ) of the housing ( 2 ). Computer program product according to claim 11, wherein by means of a time multiplexer ( 19 ) a flat and / or three-dimensional holographic image of several holographic fields is built. Computer program product according to claim 12, wherein the holographic partial images are each reproducible in a plane and wherein the planes of the holographic partial images are spaced from each other. The computer program product of claim 12 or claim 13, wherein the transmissive programmable diffractive optical element 7 with a number of optical phase modulation cells by means of the time multiplexer ( 19 ), in a time-division multiplexing with radiation of different wavelengths illuminated and a multicolored holographic image ( 13 ) from several holographic partial images after the radiation has passed through a hologram foil ( 5 ) can be built with a static optical interference grid, wherein the holographic fields have different colors.

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