DE102015206796A1 - A visual field display device for a vehicle and method of displaying an image in a field of view of a person - Google Patents

Abstract

The invention relates to a visual field display device (102) for a vehicle (100) for displaying an image in a field of view of a person. The visual field display device (102) has an imaging device (110) for providing a first partial image and a second partial image, optical means (112) for projecting the first partial image along a first light path (107) to a first eye (104) of the person a first eye area (105), and the second field along a second light path (207) to a second eye area (205) assignable to a second eye (204) of the person, and means for reducing crosstalk between the first light path (107) and the second light path (207).

Description

State of the art

The invention is based on a visual field display device for a vehicle and a method for displaying an image in the field of vision of a person according to the category of the independent claims.

Head-up displays used in the vehicle sector image the image plane of an imager unit with the help of optics to a virtual image in front of the vehicle.

The DE 40 04 739 A1 describes an optical system for the stereoscopic display of information with an optical element with lens function, two alternately switched on and off light sources and an information carrier.

Disclosure of the invention

Against this background, with the approach presented here, a visual field display device for a vehicle and a method for displaying an image in a field of vision of a person according to the main claims are presented. The measures listed in the dependent claims advantageous refinements and improvements of the independent claim device are possible.

The quality of an image displayed using a field-of-view display device can be improved by reducing crosstalk between individual light paths used to display the image.

There is provided a visual field display device for a vehicle for displaying an image in a field of view of a person having the following features:
an imaging device for providing a first partial image and a second partial image;
an optical device for projecting the first partial image along a first light path to a first eye region, which can be assigned to a first eye of the person, and the second partial image along a second light path to a second eye region, which can be assigned to a second eye of the person; and
means for reducing crosstalk between the first light path and the second light path.

A visual field display device can be understood as a head-up display (HUD), in particular an autostereoscopic head-up display. An eye area of the person can be understood as an eyebox associated with an eye of the person. An imaging device can be understood to mean an image generator unit (PGU). The imaging device may include an imager for providing the first partial image and the second partial image or a first image generator for providing the first partial image and a second image generator for providing the second partial image. An optical device can be understood to be an optical system, in particular a head-up optical system. For example, the optical device may include a plurality of mirrors for redirecting the light between an imager of the imager and the eye region. In addition, for example, a windshield of the vehicle may be part of the optical device. During operation of the visual field display device, the person can perceive the first partial image via her one eye and the second partial image via her second eye. The first partial image and the second partial image complement each other to the image, which is displayed from the perspective of the person in their field of vision. The light paths of the two partial images can run close together. This can cause crosstalk. Crosstalk can be understood as meaning that light transmitted via one of the light paths is coupled into the other of the light paths and guided along this light path to the eye region assigned to this light path. The means for reducing is designed to reduce or eliminate this crosstalk. For this purpose, different embodiments of the device for reducing can be used, which can also be used in combination. On the one hand, the crosstalk can be reduced by preventing or making it difficult to introduce light from one light path into the other light path and, on the other hand, by filtering out light already coupled in from one light path into the other light path. Advantageously, the described approach to crosstalk suppression can be used for visual field displays in the form of autostereoscopic display systems.

According to an embodiment, the means for reducing crosstalk may include a first filter disposed in the first light path and configured to filter out a second characteristic light. Further, the means for reducing may comprise a second filter disposed in the second light path and configured to filter out a light having a first property different from the second characteristic. The light having the first property may be used to transmit the image information of the first field, and the light having the second property may be used to transmit the image information of the second field. A property of light may, for example, relate to a polarization or a spectrum of the light. If light used to transmit the first partial image is unintentionally coupled into the second light path, then this light can be filtered out before the second eye region is reached using the second filter. If light used to transmit the second partial image is unintentionally coupled into the first light path, then this light can be filtered out in a corresponding manner before reaching the first eye region using the first filter.

For example, the first property may represent a first polarization and the second property a second polarization. Accordingly, the first filter may be a first polarizer for filtering second polarization light and the second filter may be a second polarizer for filtering first polarization light. Light of different polarizations can be generated easily, so that an easy-to-implement possibility for avoiding negative effects of crosstalk can be realized in this way.

For this purpose, the imaging device can be designed to provide the first partial image using light having the first polarization. Accordingly, the imaging device may be configured to provide the second field using second polarization light. Correspondingly polarized light can be advantageously generated using laser projectors or liquid crystal displays (LCDs) already used in connection with field of view displays.

Additionally or alternatively, the first property may represent a first color spectrum and the second property a second color spectrum. Accordingly, the first filter may be a first interference filter for filtering out light having the second color spectrum and the second filter may be a second interference filter for filtering out light having the first color spectrum. A color spectrum can have a plurality of individual colors. Thus, a color spectrum may include light of different wavelengths. In this case, the individual colors encompassed by the first color spectrum and thus the wavelengths encompassed by the first color spectrum may differ from the individual colors encompassed by the second color spectrum and thus from the second color spectrum. The first interference filter can be designed to filter out the individual colors encompassed by the second color spectrum and thus the wavelengths covered by the second color spectrum. Accordingly, the second interference filter can be designed to filter out the individual colors encompassed by the first color spectrum and thus the wavelengths encompassed by the first color spectrum. In this way, it can be ensured that only the first color spectrum encompasses the first eye region and the second eye region only reaches light encompassed by the second color spectrum. This can reduce or eliminate the negative effects of crosstalk.

For this purpose, the imaging device can be designed to provide the first partial image using primary colors of first wavelengths and to provide the second partial image using primary colors of second wavelengths. In this case, the primary colors of the first wavelengths may differ from the primary colors of the second wavelengths. The basic colors can be, for example, the colors red, green and blue. In this way, it is sufficient to define three wavelengths or wavelength ranges per color spectrum, ie a total of six different wavelengths or wavelength ranges. As a result, light having a first wavelength and for the second partial image light having a second wavelength deviating from the first wavelength can be used, for example, to display the primary color red for the first partial image. Accordingly, to represent the basic color green for the first partial image, light having a third wavelength and for the second partial image light having a fourth wavelength deviating from the third wavelength can be used. Finally, for representing the base color blue, light having a fifth wavelength for the first partial image and light having a sixth wavelength deviating from the fifth wavelength can be used for the second partial image.

If the means for reducing the crosstalk comprises filters, the visual field display device may advantageously comprise a tracking device for tracking the first filter in accordance with a movement of the first eye region and for tracking the second filter in accordance with a movement of the second eye region. In this way, it can be ensured that the filters during operation of the visual field display device are also in a shift of the light paths due to a movement of the person in their associated light paths.

Additionally or alternatively to the use of filters, the crosstalk reduction means may comprise a first holographic optical function in an element for backlighting an imager of the imager and a second holographic optical function in the or another element for backlighting the imager. Such backlighting can produce diffraction effects on the imager can occur and cause crosstalk, effectively prevented or reduced. The holographic optical functions can for this purpose be adapted to the diffraction properties of the imaging devices. Holograms, for example, can be used as holographic optical functions. If the imaging device has a first image generator for providing the first partial image and a second image generator for providing the second partial image, the first holographic optical function for backlighting the first image generator and the second holographic optical function for backlighting the second image generator can be provided. An imager can also be called an imager. To illuminate the two Eyeboxes different optical functions are necessary, which can be realized in two holograms, but can also be combined in a single hologram. Thus, the two optical functions according to different embodiments can be realized in the same element, or in two different holographic elements.

For example, the first holographic optical function may represent a hologram that has been illuminated through the optical device and the imager during its acquisition from the first eye area. Accordingly, the second holographic optical function may represent a hologram illuminated during its acquisition from the second eye area via the optical device and the imager. A hologram can be picked up using an object wave and a reference wave. The object waves used can be formed by guiding light via the respective eye region, the optical device and the imager or the respective imager to the position at which the respective hologram is arranged during the operation of the visual field display device. In series production, a master hologram can be recorded in this way, which is duplicated by means of contact copying. Thus, the first holographic function may represent a first master hologram duplicated using the contact-copy method and the second holographic function may represent a second master hologram duplicated using the contact-copy method. When using only one master hologram, the first holographic function and the second holographic function can correspondingly represent a master hologram duplicated using the contact copy method. Advantageously, it is not necessary in this way that each hologram installed in the final system has been exposed via the corresponding optics. It is sufficient to produce a master hologram via this exposure and to duplicate it by means of a contact copy.

A corresponding method for displaying an image in a field of view of a person comprises the following steps:
Providing a first partial image and providing a second partial image;
Projecting the first partial image along a first light path to a first eye region, which can be assigned to a first eye of the person, and the second partial image along a second light path to a second eye region, which can be assigned to a second eye of the person; and
Reducing crosstalk between the first light path and the second light path.

The steps of the method can be advantageously carried out using means of the aforementioned visual field display device. The step of reducing may be performed, for example, by filtering out light of particular characteristics in the individual light paths or by appropriate backlighting to provide the sub-images of the imaging devices used.

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. It shows:

1 a vehicle with a visual field display device according to an embodiment;

2 a vehicle with a visual field display device according to an embodiment;

3 a visual field display device according to an embodiment;

4 a visual field display device according to an embodiment;

5 a schematic representation of a visual field display device according to an embodiment;

6 a flowchart of a method for displaying an image according to an embodiment;

7 a visual field display device according to an embodiment;

8th a schematic representation of an imaging device for a visual field display device according to an embodiment;

9 a schematic representation of an imaging device for a visual field display device according to an embodiment;

10 a schematic representation of an imaging device for a visual field display device according to an embodiment;

11 a schematic representation of an imaging device for a visual field display device according to an embodiment;

12 a schematic representation of a visual field display device according to an embodiment; and

13 a schematic representation of a visual field display device according to an embodiment.

In the following description of favorable embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and similar acting, with a repeated description of these elements is omitted.

1 shows a vehicle 100 with a visual field display device 102 according to an embodiment. In the vehicle 100 a driver sits in the car 1 only a driver's eye 104 is shown. The driver's eye 104 is in an eye area 105 , which is also referred to below as Eyebox. Under an eye area 105 is thus understood an area within which the eye 104 actually or assumed way. When the driver's head moves, the eye moves 104 and a position of the eye area 105 becomes the movement of the eye 104 tracked accordingly. The visual field display device 102 is trained to be on a virtual screen 106 located in a driver's field of vision to present an image visible to the driver. This is done by light along a light path 107 guided.

The visual field display device 102 is designed as a head-up display. The in 1 shown schematic structure of the visual field display device 102 comprises an imaging device 110 in the form of a PGU (Picture Generating Unit) and an optical device 112 in the form of an optic, also called HUD optics. The imaging device 110 is hereinafter also referred to as an imaging unit 110 designated.

The head-up display 102 is formed around the image plane of the imager unit 110 using the optics 112 on a virtual, in front of the vehicle 100 image to be displayed. The driver thereby perceives an enlarged image, that of the imaging unit 110 was generated. This image is superimposed on the driving scene and is located at a defined distance from the windscreen 114 on the virtual screen 106 , In this case, a use of LCD modules as an imaging element in the imager unit 110 respectively. The windscreen 114 can also be part of the optical device 112 be understood.

The illustrated virtual image is an enlarged image of that from the imager unit 110 generated displays. Therefore has the HUD optics 112 a certain magnification. The necessary magnification increases with the distance of the virtual screen 106 too, because of the imager unit 110 generated image must be increased in order to take the desired field of view of the driver at a greater distance. For example, the virtual screen 106 at a distance of about 15 m.

As a virtual image can during the operation of the head-up display 102 on the virtual screen 106 For example, symbols or characters are displayed from the perspective of the driver behind the windscreen 114 appear.

2 shows a vehicle 100 with a visual field display device 102 according to an embodiment. The representation corresponds to the basis of 1 described representation, in 2 especially an illustration of the basic operation of an autostereoscopic head-up display 102 is shown. Therefore, in 2 two eyes 104 . 204 shown by the driver. The eye 104 is in an eye area 105 and the eye 204 in an eye area 205 ,

The autostereoscopic HUD system 102 works with separate partial images for left and right eye 104 . 204 by which a 3D effect similar to that known by the cinema can be generated. The imager unit 110 already creates the two partial images. About the HUD optics 112 the light of the partial images then becomes the respective eye 104 . 204 in the smaller eyeboxes 105 . 205 made available. These are two separate light paths 107 . 207 used.

3 shows a visual field display device 102 according to an embodiment. This may be an embodiment of the basis of 2 only schematically illustrated field of view display device 102 act. Shown is the field of view display device 102 the example of a HUD design for enlarging a small imager, a so-called imager. The imager of the imager unit 110 will have four free-form mirrors 321 . 322 . 323 . 324 and the windshield 114 imaged virtually. The free-form mirror 321 . 322 . 323 . 324 and the windshield 114 can be considered the optical device 112 of the visual field display device 102 be understood.

4 shows a schematic representation of a visual field display device 102 according to an embodiment. These may be the ones based on 2 described visual field display device 102 act. Shown is the field of view display device 102 as a crosstalk-prone system, ie a system in the crosstalk between the light paths 107 . 207 occurs.

By scattering or diffraction on various surfaces within the HUD system 102 , part of the light can be for one eye 104 , in the direction of the other eye 204 be steered. It creates a crosstalk from one eye 104 into the other eye 204 , To prevent part of the light for one eye 104 , in the direction of the other eye 204 is steered, or, to prevent being already in the direction of the other eye 204 directed light on the eye 204 meets, the visual field display device 102 with a device described in detail below for reducing crosstalk between the first light path 107 , the light for the eye 104 includes, and the second light path 207 , the light for the eye 204 includes, equipped.

An essential criterion of the quality of the stereoscopic display system 102 is the unwanted crosstalk of the image information of one of the two eyes 104 in the other eye 204 , One speaks with this crosstalk of the so-called Crosstalk. Too high a level of crosstalk leads to visual overload such as discomfort, fatigue and can lead to complete loss of the 3D impression.

Crosstalk can be generated in different places of the optical system and has different causes. Especially the imager unit 110 is in the generation of the two fields of an autostereoscopic head-up display 102 crosstalk vulnerable. If, for example, scattering surfaces are used to produce the two partial images, crosstalk is produced due to the Gaussian radiation in broad eyeboxes. Another important effect is the formation of crosstalk due to diffraction effects on the image generator 110 , An LCD module, for example, has a very narrow pixel pitch (RGB subpixels in the range of approximately 30 μm) at high resolutions. This grid acts as a diffraction-like optical grid and thus leads to higher orders of the eyebox, which can produce clearly visible crosstalk. Similar crosstalk-producing diffraction effects arise in the case of direct-imaged imagers, for example in digital light processing (DLP), in which a digital image is modulated onto a light beam or in microlens arrays with a small pitch. The resulting crosstalk is particularly difficult to eliminate because it is directly on the imaging element 110 arises and must be suppressed without damaging the image information.

Using the crosstalk reducing means mentioned above, the crosstalk of the partial images in the imager unit may be in the wrong eye 104 . 204 be effectively reduced. In particular, the crosstalk resulting from diffraction effects can also be reduced.

5 shows a schematic representation of a visual field display device 102 according to an embodiment. As already stated, the visual field display device is 102 formed to a first partial image via a first light path using an optical device 107 in the direction of a first eye area associated with a first eye 105 and a second field via a second light path 207 in the direction of a second eye area associated with a second eye 205 to project. For providing the first partial image and the second partial image, the visual field display device 102 an imaging device.

The visual field display device 102 has means for reducing crosstalk between the first light path 107 and the second light path 207 on. By reducing, it can be understood that crosstalk is prevented or reduced from the outset, or at least crosstalk that has already occurred is at least reduced. For this purpose, the device for reducing, as in 5 schematically illustrated several different and can be arranged at different positions elements 521 . 523 . 525 . 527 which can be used alone or in combination.

According to an embodiment, the means for reducing comprises filters 521 . 523 in the light trails 107 . 207 between the imaging device 110 and the eye areas 105 . 205 are arranged. The filters 521 . 523 can do this in the optical device 112 integrated or between the imaging device 110 and the optical device 112 be arranged. The first light path 107 associated first filter 521 is configured to filter out a second property light used to represent the second field. The second light path 207 associated second filter 523 is configured to provide light having a first property, which is used to display the first partial image, filter out. The first property may represent a first polarization and the second property a second polarization of the light used to represent the fields. In this case, the filters 521 . 523 be executed as a polarizing filter. Additionally or alternatively, the first property may represent a first color spectrum and the second property a second color spectrum. In this case, the filters 521 . 523 or additional filters 521 . 523 be executed as an interference filter.

According to one embodiment, the visual field display device comprises 102 a tracking device 530 that is designed to filter 521 . 523 track if this is due to a change in position of the eye area 105 . 205 is required. The tracking device 530 For example, it is realized as a mechanism configured to perform the tracking in response to a reception of a control signal.

According to a further embodiment, the means for reducing comprises additionally or alternatively to the filters 521 . 523 holographic optical elements 525 . 527 , A first holographic optical element 525 is provided to a provided for providing the first partial image image generator of the imaging device 110 to backlight and a second holographic optical element 527 is provided to an imager provided for providing the second partial image of the imaging device 110 to backlight. The holographic optical elements 525 . 527 can be designed as separate components or as areas of a single component.

For crosstalk reduction thus three approaches are pursued. The core of the first approach is the separation of the polarizations of the two partial images and the use of filters designed as polarizing filters 521 . 523 in the optical beam path, which offer the respective eye only the polarization of a partial image. The second approach works in a similar way but uses separation by different wavelengths instead of polarization separation. The core of the third approach is the use of a holographic optical element 525 . 527 (HOE) as the backlight of the imager 110 to the diffraction properties of the imager 110 to compensate with a corresponding phase grating. This allows the backlight light to be diffused into narrow angles, thereby achieving low crosstalk levels.

A reduction in the crosstalk level has a positive effect on the image quality of the display system. The crosstalk reduction prevents visual overload and reduces fatigue associated with prolonged viewing of the stereoscopic image. This allows a comfortable and long-term use of the display system 102 and increases the comfort considerably. On the other hand, the contrast of the individual partial images is increased by the reduction of crosstalk. Through holographic elements 525 . 527 The functions of conventional optical elements can be summarized. In addition, virtual light sources can be generated at arbitrary intervals that go beyond the spatial dimension of the design. The use of holograms 525 . 527 thereby effectively reduces the installation space.

The holograms 525 . 527 represent holographic functions that may be implemented in separate elements or in one element according to different embodiments. Are the holographic functions 525 . 527 together in one element, for example the imager 110 realized, so can the two holographic functions 525 . 527 during operation of the visual field display device 102 be illuminated from different directions. Will the element with the holographic functions 525 . 527 illuminated from a first direction of illumination, so the first eye area 105 to be served. Will the element with the holographic functions 525 . 527 on the other hand illuminated from a second direction of illumination, so the second eye area 205 to be served.

6 FIG. 10 is a flowchart of a method of displaying an image according to an embodiment. FIG. For example, the image may be based on 2 shown on a virtual screen within the field of view of a person. This will be done in one step 601 initially provided two fields, for example, using the basis of 2 shown imaging device. In a step parallel to that 603 For example, one of the partial images is directed to a first eye of the person via a first light path, and the other of the partial images is directed via a second light path to a second eye of the individual using, for example, FIG 2 shown optical device. In a step parallel to that 605 Crosstalk between the light paths is prevented or at least reduced, for example using the basis of 5 shown device for reducing.

7 shows a visual field display device 102 according to an embodiment. Shown is an example of a HUD design for enlarging a small imager. Shown are the ones relating to a direction of the light paths 107 . 207 first elements 110 . 321 . 322 the visual field display device 102 already based on 3 are described. Because the paths 107 . 207 The two fields for left and right eye here completely separated spatially are, can polarizer 521 . 523 filter out the light that crosstalks into the wrong eye.

Instead of polar filters 521 . 523 For example, interference filters may be used in a similar manner when transmitting the fields via the paths 107 . 207 Light of different color spectra is used.

8th shows a schematic representation of an imaging device 110 for a visual field display device according to an embodiment. Shown is a schematic example of the imaging device 110 in the form of a PGU with two LED projectors 810 . 811 , The LED projectors 810 . 811 can be used as an imager of the imaging device 110 be understood. The light of the two projectors 810 . 811 is ever using a polarizing filter 821 . 823 each linearly polarized. The first LED projector 810 associated polarization filters 821 is as a + 45 ° pole filter and the second LED projector 811 associated polarization filters 823 is designed as a -45 ° Pol filter. The 90 ° polarized sub-images of the LED projectors 810 . 811 can then be optically filtered through the separate imaging paths on the wrong eye, for example using the in 7 shown polarizing filter. The element 825 represents a scattering surface or a microlens array.

9 shows a schematic representation of an imaging device 110 for a visual field display device according to an embodiment. Shown is a schematic example of the imaging device 110 in the form of a PGU with two laser projectors 910 . 911 , The laser projectors 910 . 911 can be used as an imager of the imaging device 110 be understood. By using the laser projectors 910 . 911 the two partial images are already polarized. The projectors 910 . 911 are designed so that their images are polarized 90 ° to each other. The polarized sub-images can then be filtered out in optics by the separate imaging paths on the wrong eye, for example using the in 7 shown polarizing filter.

10 shows a schematic representation of an imaging device 110 for a visual field display device according to an embodiment. Shown is a schematic example of the imaging device 110 in the form of a PGU at the two LCDs 1010 . 1011 be superimposed. The LCDs 1010 . 1011 can be used as an imager of the imaging device 110 be understood. Through the two LCDs 1010 . 1011 the sub-images are linearly polarized. With appropriate orientation of the located on the LCD modules polarizing filter partial images can be generated, which are polarized 90 ° to each other and can be filtered out via an optic, for example using the in 7 shown polarizing filter. Each of the LCD modules includes a scattering surface or a microlens array 825 and a light emitting diode 1025 , The imager unit further comprises a beam splitter 1030 ,

11 shows a schematic representation of an imaging device 110 for a visual field display device according to an embodiment. Shown is a schematic example of the imaging device 110 in the form of a PGU with two light-emitting diode devices 1110 . 1111 with which a small imager 1140 , Here, for example, a DLP chip, so a chip for Aufmodulierung a digital image on a light beam, is displayed directly. Each of the light-emitting diode devices 1110 . 1111 includes a light emitting diode 1142 , a polarizer 1044 , a collimation lens 1146 , a microlens array 1148 and a projection lens 1150 , The polarizer 1144 the light emitting diode device 1110 is as a + 45 ° polarizing filter and the polarizing filter 1144 the light emitting diode device 1111 is designed as a -45 ° polarizer. Due to the polarized by the filter LED light, the two fields of the Bildgebereirichtung 110 also polarized 90 ° to each other and can be filtered out in the subsequent optical system in the wrong imaging path, for example using the in 7 shown polarizing filter.

The following are based on the 3 to 11 Embodiments for Crosstalkreduktion by laser illumination and polarizing filter described in detail.

Uses the Imager device 110 In the generation of the left and right eye fields, polarized light can be prevented by filtering each wrong polarization from the optical path of the light to an eye. For this purpose, an optical design is used, in which at least one point, the two light paths 107 . 207 are completely separated for the drawing files.

In 3 is a designed HUD look 112 shown for a small imager. This imager is about four free-form mirrors 321 . 322 . 323 . 324 and the windshield 114 magnified and displayed virtually. In 7 a section of this HUD system is shown. Shown are the imager of the imager unit 110 , the first two mirrors 321 . 322 , as well as additionally introduced polarization filters 521 . 523 , In this design are the optical paths 107 . 207 the two fields still completely separated. This allows the positioning of two polarizing filters 521 . 523 in the path 107 . 207 the little eyebox 107 . 207 for one eye each. A crosstalk of the light into the eyebox 107 . 207 the other eye is effectively filtered.

To generate the two polarization directions, for example, an LED with further polarization filter 821 . 823 . 1044 as backlighting of the imager in the imaging device 110 be used in the form of a PGU. Another approach is the use of a laser backlight, which is pre-polarized by itself, as it is based on 9 is described. In this case, the efficiency of the overall system continues to increase, since no large Nutzlichtanteile be filtered.

The tracking of the Eyeboxes 105 . 205 in head movements of the user also enforces a tracking of the two polarizing filters 521 . 523 , The tracked area of these filters 521 . 523 However, it is low and only needs to be done in one axis. The temporal requirement of this tracking is also below the requirement for, for example, the Eyeboxnachführung itself, because the polarizing filter 521 . 523 have sharply defined apertures and have a certain overlap over the eyebox rays. For tracking, the in 5 schematically shown tracking device 530 be used.

The imaging device 110 , also called an imaging unit, can be designed differently. In principle, the described concept can be applied to every imager unit 110 which is able to provide the two partial images in different polarizations. The radiation of the display of the imaging unit 110 is in each case to the used optical concept of the imaging HUD mirror 321 . 322 . 323 . 324 customized.

According to one embodiment, an imager unit 110 used by two projectors 810 . 811 realized on a scattering surface or a microlens array 825 project as it is in 8th is shown. The two projectors 810 . 811 are placed in such a way that the two partial images radiate in different directions from the projection surface. By using polarizing filters 821 . 823 The resulting two partial images can be polarized by 90 ° to each other. The so polarized fields take in the subsequent imaging optics at least one place completely separate paths 107 . 207 , Crosstalk floods a drawing file in the wrong path 107 . 207 so it can be filtered out there.

When using laser projectors 910 . 911 can with appropriate design of the projectors 910 . 911 the polarization property of the laser light can be directly exploited, as it is in 9 is shown. The projector 910 . 911 can also be realized as a flying spot projector.

In 10 is a possible concept of an LCD unit-based imager unit 110 shown. There will be two LCDs 1010 . 1011 by means of a beam splitter 1030 so backlit that they produce the two partial images for stereoscopic vision. The backlighting by means of the LED light is designed such that the two fields after the beam splitter 1030 radiate in slightly different directions. Through the LCDs 1010 . 1011 is the respective field naturally polarized. Be the polarizing layers of the LCDs 1010 . 1011 designed accordingly, so can be realized by 90 ° to each other polarized partial images, which in turn can be filtered out in the following optics.

Also concepts with the direct image of small imagers 1140 can be realized with polarized partial images. 11 shows an example in which a DLP chip as an imager 1140 is shown. The backlight of the imager 1140 takes place from two different directions to realize the two partial images. The light of an LED 1142 is thereby polarized and a collimating lens 1146 collected. After a homogenization step through a microlens array 1148 and a projection lens 1150 the light is on the imager 1140 directed.

According to a further embodiment, an imager concept is realized in which two liquid crystal on silicon (LCoS) chips, ie two liquid crystals on silicon substrate, are illuminated accordingly.

Overall, the proposed concept can be applied to various imaging units. The partial images need not necessarily be polarized ± 45 °. A polarization by 90 ° to each other, however, is advantageous because the two fields are so effectively separated. The use of ± 45 ° additionally offers the advantage that the windshield 114 the two partial images reflect approximately equally strong and the two partial images remain bright. However, the actual design may differ.

Alternatively to filtering by in 7 shown polarizing filter 521 . 523 Interference filters can be used if the basic colors of the partial images differ spectrally for the two eyes. The image for the left eye then uses different wavelengths for red, green, and blue than the other field does. For this purpose, laser illuminations with a narrow frequency width are suitable. The system is then operated at six different wavelengths. For this purpose, laser displays with, for example, up to six different wavelengths and associated Interference filters are used. In this way, crosstalk suppression by interference filters can be performed. An arrangement of the interference filters may be according to the arrangement of the polarizers described.

12 shows a schematic representation of a visual field display device 102 according to an embodiment. The visual field display device 102 is used to form a holographic optical element, according to this embodiment, a holographic function, hereinafter also as a hologram 525 designated to record. The recorded hologram 525 may subsequently during operation of the field of view display device 102 for generating a backlight of an imager 1260 the imaging device 110 , here for example for backlighting of an imager 1260 in the form of a DLP chip or a LCoS chip.

To record the hologram 525 become an object wave 1261 and a reference wave 1262 on the hologram 525 directed. The object wave 1261 is from a lighting 1264 generates their light through the optics 112 and the imager 1260 to the hologram 525 after its inclusion as part of the imaging device 110 can be viewed.

Thus shows 12 an arrangement of a structure for receiving a hologram 525 via an imager 1260 , for example in the form of a DLP chip. The lighting 1264 takes place from the position of the eyebox and is via the imager 1260 , and the optics 112 on the hologram 525 directed. Together with the reference wave 1262 Form certain phase patterns that are in the hologram 525 memorize.

A hologram created in this way 525 can be used as a master hologram that can be duplicated using a contact copying method.

13 shows a schematic representation of a visual field display device 102 according to an embodiment. These may be the ones based on 12 described visual field display device act in which a lighting 1366 is used to over the hologram 525 a backlight for the imager 1260 the imaging device 110 generate a subpicture over one of the optical device 112 guided light path 107 to the eye area 105 in the form of an eyebox. In this way, that can be done via the light path 107 guided light can be understood as a reconstruction.

That, as based on 12 described recorded hologram 525 can thus be played by the lighting 1366 done from the other side. As a result, the object wave used in recording is generated backwards and it forms on the imager 1260 and the optics 112 the eyebox again 105 that was lit during the recording.

Based on 5 such as 12 and 13 In the following, a crosstalk reduction by HOE backlight according to different embodiments will be described.

The imagers 1260 In addition, a display system also has diffractive properties that occur especially in very small structures. Common high-resolution LCDs 1260 have pixels that already have diffraction effects due to the lattice structure of their arrangement. Often the grids are finer than the actual specified pixel sizes by a factor of 3 because a single pixel consists of three subpixels for the colors red, green and blue (subpixels approx. 30 μm). Likewise, imager imager work 1260 like LCoS or DLP chips with pixel sizes in the diffractive range (about 10 μm).

With wide-angle backlighting as used in ordinary displays, such diffraction effects fade into the background as the diffraction orders are superimposed at different angles. However, the narrower the illumination angles become, the more they emerge. Especially with autostereoscopic displays, it is important to have narrow emission cone on the PGU display 1260 because the image information for the two eyes should be clearly separated. The higher diffraction orders of the imager structures produce diffracted light that can crosstalk in the wrong eyebox. This suffers the image quality, it creates crosstalk and reduces the contrast.

One way to reduce this effect is the already described approach of using filters in the light paths.

Another possibility is the backlighting by a holographic optical element 525 as a phase pattern that suppresses the higher diffraction orders. This can be done by an appropriate hologram 525 be achieved.

Such a hologram 525 can be through the backward shot over the imager 1260 be generated, as exemplified in 12 is shown. The recording is done via the later to be used optics 112 and the imager 1260 itself. Together with the reference wave 1262 becomes a certain phase pattern in the hologram 525 marked, the later playback again exactly the object wave 1261 generated. There are then no longer higher diffraction orders, as these are due to the phase pattern of the hologram 525 be eliminated. The Huygens' elemental waves appearing in the lattice of the diffractive element 1260 arise, are then differently modulated in different directions.

When playing the hologram 525 as it is in 13 is shown, now the object wave 1261 generated backwards by the lighting 1366 on the other side of the hologram 525 is positioned. So is played over the imager 1260 and the optics 112 the eyebox again 105 displayed.

Analogous to the recording by the optics 112 can a corresponding hologram 525 calculated and written directly mechanically. A designed hologram 525 can be inexpensively duplicated by contact copies.

According to a further embodiment, instead of the in 12 recorded transmission hologram 525 , resorting to reflexive holograms. These are characterized by a clearer spectral separation and sharper demarcated angles of radiation.

A second eyebox can now through another separate hologram 527 are formed, analogous to the first hologram 525 recorded and illuminated.

A hologram 525 . 527 is also able to record different phase patterns for the three basic colors red, green and blue. This can be a hologram 525 . 527 for each of the three basic colors of an eyebox 105 . 205 be used.

While recording the hologram 525 . 527 works with laser light, a hologram so recorded 525 . 527 also with LED light as lighting 1366 be played. The basic function is not lost, however, the spectral width of the LED leads to a widening or washing out of the Eyebox thus created 105 . 205 to a certain degree. The degree of leaching at the edge of the eyebox 105 . 205 depends essentially on the spectral width of the LED. A method around the eyebox 105 . 205 Nevertheless, to keep it narrow, is to use a much narrower eyebox when recording, as will be reconstructed later. Also conceivable are the use of spectral filters or LEDs which have been optimized for narrow frequency characteristics.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 4004739 A1 [0003]

Claims (10)

Visual field display device ( 102 ) for a vehicle ( 100 ) for displaying an image in a field of view of a person, comprising: an imaging device ( 110 ) for providing a first field and a second field; an optical device ( 112 ) for projecting the first partial image along a first light path ( 107 ) to a, a first eye ( 104 ) of the person assignable first eye area ( 105 ), and the second partial image along a second light path ( 207 ) to one, a second eye ( 204 ) of the person assignable, second eye area ( 205 ); and means for reducing crosstalk between the first light path (FIG. 107 ) and the second light path ( 207 ). Visual field display device ( 102 ) according to claim 1, wherein the means for reducing crosstalk comprises a first filter ( 521 ), which in the first light path ( 107 ) and is configured to filter out light having a second property, and a second filter ( 523 ), which in the second light path ( 207 ) and configured to filter out a light having a first property different from the second property. Visual field display device ( 102 ) according to claim 2, wherein the first property represents a first polarization and the second property represents a second polarization and the first filter ( 521 ) a first polarizing filter for filtering second polarization light and the second filter ( 523 ) is a second polarizing filter for filtering out light having the first polarization. Visual field display device ( 102 ) according to claim 3, wherein the first imaging device ( 110 ) is configured to provide the first field using first polarization light, and the second device (FIG. 110 ) is configured to provide the second field using second polarization light. Visual field display device ( 102 ) according to claim 2, wherein the first property represents a first color spectrum and the second property represents a second color spectrum and the first filter ( 521 ) a first interference filter for filtering out the second color spectrum having light and the second filter ( 523 ) is a second interference filter for filtering out light having the first color spectrum. Visual field display device ( 102 ) according to claim 5, wherein the imaging device ( 110 ) is adapted to provide the first field using primary colors of first wavelengths and the second field using primary colors of second wavelengths, wherein the primary colors of first wavelengths are different from the primary colors of second wavelengths. Visual field display device ( 102 ) according to one of claims 2 to 6, with a tracking device ( 530 ) for tracking the first filter ( 521 ) corresponding to a movement of the first eye area ( 105 ) and for tracking the second filter ( 523 ) corresponding to a movement of the second eye area ( 205 ). Visual field display device ( 102 ) according to claim 1, wherein the means for reducing crosstalk comprises a first holographic optical function in an element ( 525 ) for backlighting an imager ( 1260 ) of the imaging device ( 110 ) and a second holographic optical function in the element ( 525 ) or another element ( 527 ) for backlighting the imager ( 1260 ) of the imaging device ( 110 ) having. Visual field display device ( 102 ) according to claim 8, wherein the first holographic function represents a hologram which, during its acquisition from the first eye area ( 105 ) via the optical device ( 112 ) and the imager ( 1260 ), and in which the second holographic function represents a hologram that during its recording from the second eye area ( 205 ) via the optical device ( 112 ) and the imager ( 1260 ), or wherein the first holographic function and the second holographic function represent at least one master hologram duplicated using a contact copying method. A method of displaying an image in a field of view of a person, the method comprising the steps of: providing ( 601 ) of a first field and providing a second field; Projecting ( 603 ) of the first partial image along a first light path ( 107 ) to a, a first eye ( 104 ) of the person assignable first eye area ( 105 ), and the second partial image along a second light path ( 207 ) to one, a second eye ( 204 ) of the person assignable, second eye area ( 205 ); and diminishing ( 605 ) of a crosstalk between the first light path ( 107 ) and the second light path ( 207 ).

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