DE102009043351A1 - A method for generating a stereo image by a projection unit for a head-up display and projection unit for a head-up display - Google Patents

Abstract

The method is used to generate an image (18) by a projection unit (11) for a head-up display (19), the method having at least the following steps: generating at least two non-overlapping projection light bundles (23r, 23r); Generating different image information for the two projection light bundles (23r, 23r) and impressing the generated different image information on the two projection light bundles (23r, 23r). The projection unit (11) is set up to carry out the method. The vehicle (10) is equipped with a head-up display (19), the head-up display (19) having the projection unit (11) in which an image generated by the head-up display (19) (18) is mapped onto a front window (17) of the vehicle (10).

Description

The invention relates to a method for generating an image by a projection unit for a head-up display, a projection unit for a head-up display and a vehicle with a head-up display, wherein the head-up display has the projection unit ,

A head-up display (HUD) is a display system in which the important information for a viewer (pilots, motorists, etc.) is projected into his field of view. A so-called 'eyebox' is understood to mean that three-dimensional space in which both eyes of the observer can see an image produced by the head-up display completely and untrimmed. In other words, the 'eyebox' is that area of space within which a viewer can use or recognize the functions of the head-up display. By means of the eyebox, a viewer is allowed a certain head movement when viewing the image, and different large or tall observers can be considered. The eyebox of a HUD is typically uniformly illuminated.

The head-up display (HUD) displays a static (HUD) image regardless of a position of the viewer's eye. In particular, the viewer thus sees with both eyes the same static display from the same perspective. A correction of the HUD image, the z. B. the windshield geometry is required, by the shape of one or more image-distorting optical elements (eg., Mirrors and / or lenses) performed and additionally by an electronic Bildvorverzerrung. This image correction is the same for all Eyebox or Eyebox locations.

However, referencing of image contents of the HUD image to the outside world, which is also viewed through the windshield, so far graphically consuming. In addition, the image-distorting optics required for correcting the HUD image is windshield-specific and therefore more expensive. Furthermore, the image distorting optics can only correct those aberrations that are the same from all Eyebox eye positions. Artifacts that assume different types or dimensions in different eyebox positions are thus not correctable. In order to keep these position-dependent aberrations low, the degrees of freedom for a design of the windshield and thus also for an embodiment of the vehicle are very limited.

It is the object of the present invention to provide a projection method which avoids one or more of the disadvantages mentioned and, in particular, makes it possible to illuminate the eyebox with poor image quality and realistic illumination.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims.

• – Erzeugen von mindestens zwei sich zumindest in der Eyebox bzw. in den Eyeboxen nicht überlappenden Projektionslichtbündeln;
• – Erzeugen unterschiedlicher Bildinformation für die Projektionslichtbündel; und
• – Aufprägen der erzeugten unterschiedlichen Bildinformation auf die Projektionslichtbündel.

The object is achieved by a method for generating an image by a projection unit for a head-up display, the method having at least the following steps:

• Generating at least two projection light bundles which do not overlap, at least in the eyebox or in the eyeboxes;
• Generating different image information for the projection light beams; and
• - Imprinting the generated different image information on the projection light beam.

Each of the projection light beams is for viewing by a respective eye of a viewer. By imprinting the different image information, image information specific to the respective projection light bundle can be provided. The virtual image can thus be constructed with an eye-dependent different image information, which, for example, allows a more realistic or more natural-looking image reproduction and / or a physiologically compatible image perception (head pain factor).

The projection light bundles thus do not overlap at least in a distance from the front screen directed towards a viewer. The distance may in particular be at least 30 cm, in particular at least 40 cm, in particular at least 120 cm, in particular at least 150 cm.

• – Erzeugen von mindestens zwei sich nicht überlappenden Projektionslichtbündeln;
• – Zeitlich abwechselnde Aktivierung der Projektionslichtbündel;
• – Erzeugen stereoskopisch unterschiedlicher Bildinformation für die Projektionslichtbündel; und
• – Aufprägen der erzeugten unterschiedlichen Bildinformation auf die Projektionslichtbündel.

It is an embodiment that the method for generating a stereo image by the projection unit for a head-up display and at least comprises the following steps:

• - generating at least two non-overlapping projection light beams;
• - Time-alternating activation of the projection light beam;
• Generating stereoscopically different image information for the projection light bundles; and
• - Imprinting the generated different image information on the projection light beam.

Through this temporally alternating activation of the at least two projection light bundles with the stereoscopically different image information, a viewer can be given a three-dimensional image. The three-dimensional image is better than a two-dimensional image able to refer to even complex issues relating to the outside world or complex issues in that of the viewer in particular by the Front glass considered to embed image of the outside world.

In an alternative embodiment for generating a stereo image, the at least two projection light bundles (for the left eye and the right eye) can be generated by differently colored light sources, and the different image information for the projection light bundles can be applied in different different color channels of the display that are suitable for the projection light bundles become. Since the differently colored projection light bundles do not overlap in the eyebox, in this case a temporally alternating activation of the projection light bundles can be dispensed with.

It is also an embodiment that the projection unit emits or generates exactly two projection light bundles, that is, one eye for each eye. The exactly two projection light bundles can be referred to as a left and a right projection light beam. The use of precisely two projection light bundles simplifies a construction of the projection unit and in particular an image impression on the projection light bundles and allows an energetically maximally efficient design.

It is a further embodiment that the projection light beams are activated alternately in time with a frequency of at least 120 Hz. This fast image sequence allows a fluid representation of image content and prevents disturbing image effects such as flicker.

It is still an embodiment that at least part of the stereoscopically different image information is precalculated and is currently retrieved. As a result, the head-up display is relieved of a computing activity and can be performed simpler and cheaper.

It is an alternative or additional embodiment that at least part of the stereoscopically different image information is currently calculated. As a result, a particularly situation-adapted image structure is possible.

It is a further embodiment that the stereoscopically different image information comprises an eye-dependent distortion correction. The light bundle-specific, eye-dependent image correction only needs to correct the geometry of the region of the windshield at which the respective projection light beam is mirrored. As a result, the degrees of freedom for a design of the windscreen can be extended.

It is yet a further embodiment that for impressing the generated different image information on the two projection light bundles at least one light source and at least one associated imaging displays of the projection unit are controlled synchronized.

The output is also solved by a projection unit for a head-up display, which is arranged to perform the above-mentioned method. Accordingly, the projection unit or the head-up display can be configured analogously.

It is a further development that the projection unit has at least one respective light source for generating each of the two projection light bundles which do not overlap, at least in the eyebox. As a result, the light bundles can be particularly easily decoupled from each other and generated.

It is an alternative development that the projection unit has at least one common light source and one of the common light source optically downstream, temporally switchable beam deflection unit, in particular beam splitter. This can reduce the number of light sources.

It is still a further development that the image generator for generating one of the projection light bundles has exactly one light source. If the projection unit for generating one of the projection light bundles has a respective light source, this means that a total of two light sources are present, namely one for each projection light bundle. If the projection unit for generating the two projection light bundles has a light source and the beam splitter, this means that overall only one light source is present. When using just one light source, lower intensity inhomogeneities occur than with a group of point light sources, or even virtually no disturbing intensity inhomogeneities. In the case of a group of point light sources, a diffuser for homogenizing a brightness distribution is additionally required, while it may possibly be dispensed with in the case of a single light source.

It is a particular development that the light source has exactly one light emitting diode, in particular an inorganic light emitting diode or a planar organic light emitting diode (OLED). Light-emitting diodes have the advantage of a very fast switching speed, a long service life and a low heat radiation. However, any other suitable light source, e.g. B. surface spotlights are used. When using the area radiator, there are lower intensity inhomogeneities than with a group of point light sources, or even virtually no disturbing intensity inhomogeneities. In addition, the Beam angle can be kept small, which allows a compact design

Generally, the display may be a backlit display, e.g. As an LCD display. According to alternative embodiments, the imager may also be a DLP unit, an LCOS unit, a laser projector, a self-luminous display (eg, an OLED display or a VFD display), and so on. In general, both reflective displays and transmissive displays can be used.

The object is further achieved by a vehicle with a head-up display, wherein the head-up display has the projection unit as described above, wherein an image generated by the head-up display is imaged on a windscreen of the vehicle.

In the following figures, the invention will be described schematically with reference to an embodiment schematically. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

1 shows a sketch of a projection unit according to the invention of a head-up display; and

2 shows a front view of eye-specific Eyeboxen generated by the projection device according to the invention;

3 shows in plan view a first arrangement of light sources and an imaging display of a projection device according to the invention;

4 shows in plan view a second arrangement of light sources and an imaging display of a projection device according to the invention;

5 shows in plan view a third arrangement of light sources and an imaging display of a projection device according to the invention;

6 shows in plan view a fourth arrangement of light sources and an imaging display of a projection device according to the invention.

1 outlines a projection unit according to the invention 11 a head-up display 19 of a vehicle 10 , The projection unit 11 has two light emitting diodes 12l and 12r on, which are arranged in the viewing plane shown one behind the other (ie with a view in the direction of travel left and right side by side), but are shown offset for a clear description. More specifically, a right LED 12r in the direction of travel right and a left LED 12r arranged in the direction of travel left to each other. The two LEDs 12l . 12r are white LEDs and emit respective projection light beams 23l respectively. 23r from. Only because of the side view are the two projection light bundles 23l . 23r superimposed drawn, but are at least in parts, especially at least in an eyebox 21l . 21r laterally offset, non-overlapping light bundles. Such an arrangement is also in 3 shown.

The two LEDs 12l . 12r emit their respective projection light bundles 23l respectively. 23r on a condenser 13 in the form of one or more lenses (alternatively or additionally: mirrors or diffractive optics) to the projection light bundles 23l . 23r to create. The condenser 13 is a through the projection light beam 23l . 23r backlit imaging display 14 in the form of a bildpunktansteuerbaren LCD displays optically downstream. The of the two LEDs 12l . 12r produced projection light bundles backlight the imaging display 14 ,

The through the imaging LCD display 14 Bildbeaufschlagten projection light bundle are thrown on a bildvergrößerndes optical element, which here in the form of a reflector 15 is designed. The reflector 15 Throws the projection light bundles Bildvergrößernd through a transparent cover 16 the projection unit 11 on a windshield 17 of the vehicle 10 , From the windscreen 17 of the vehicle 10 the projection light beams are at least partially reflected further in the direction of a driver. The driver appears through the projection light beams 23l . 23r a virtual HUD image 18 in front of the windscreen 17 if it is in the range of eye-specific eyeboxes generated by the projection light bundles 21r . 21l looking at the windscreen. The driver looks with his right eye in the from the right (alternatively: left) LED 12r produced projection light bundles (corresponding to the 'right eyebox' 21r ) and with his left eye in the from the left (alternatively: right) LED 12l produced projection light bundles (corresponding to the left eyebox ' 21l ).

In particular, the separate imaging areas of the imaging LCD display 14 so by control unit 20 be driven to produce different images. For example, the different images may be different pre-distorted images, which take into account the different geometries of the paths of the two projection light bundles, eg. B. with respect to a locally different curved and / or spaced surface of the windshield 17 ,

Alternatively or additionally, the different images may be alternately displayed partial images of a 3D image with a stereoscopically different image information. This can be done by the control unit 20 the projection light beams 23l . 23r alternating in time, z. B. with a frequency of 120 Hz or more, are activated and synchronized with the stereoscopically different image information to be acted upon.

As in 2 shown, the eyebox is no longer uniform, but in the two by the projection light beam 23l . 23r defined eyeboxes, namely the right eyebox 21r and left eyebox 21l , divided. Both eyeboxes 21r . 21l or projection light bundle 23l . 23r Here in each case have a cross section with a circular curved outer contour 22 on. The separated eyeboxes 21r . 21l allow viewing a three-dimensional HUD image 18 ,

The eyeboxes 21l and 21r each have a distance of about 30 cm to 150 cm from the windscreen 17 on, a width of about 5 to 10 cm, a height of about 15 cm and a depth of about 25 cm. This means that the projection light bundles 23l . 23r at the latest from a distance of 30 cm to 40 cm from the windscreen 17 at least partially decouple need.

Due to the fact that the respective left or true projection light bundle 23l respectively. 23r To cover a narrower angle range than in a conventional Eyebox, also a higher contrast can be maintained. Also, the area of eyeboxes can be 21r . 21l be reduced, which increases the local light intensity or the projection unit can be designed more energy efficient.

In addition, because the projection unit for generating each of the two projection light bundles 23l . 23r exactly one light source 12r . 12l no inhomogeneities between several light intensity maxima need to be compensated. Furthermore, the use of a respective light-emitting diode as the light source has the advantage that a light-emitting diode as a Lambertian radiator has virtually no angle-dependent inhomogeneities and thus does not require a diffusing screen or another diffuser.

In the following figures, various possible arrangements of light sources and imaging display together with the projection light beams generated therefrom 23l . 23r explained in more detail:

3 shows in plan view in more detail a first possible arrangement of the light sources 12r . 12l and the imaging display 14 a projection unit, z. B. the projection unit 11 , Both light sources 12l and 12r that z. B. can be configured as white LEDs, are arranged left and right side by side. They each have a lens 13l respectively. 13r as a condenser for generating the respectively emitted by them projection light beam 23l . 23r downstream. The projection light bundles 23l and 23r shine through the imaging display 14 at a left imaging area 24l or a separate right imaging area 24r , so that the projection light beam 23l and 23r different images can be imprinted, z. B. for a projection light beam-specific image correction and / or for a structure of a stereo image. The imaging display 14 here is an LCD display; In general, however, both transmissive displays, reflective displays and self-luminous displays can be used.

In particular, the control unit 20 the left light source 12l turn on and at the same time on the left imaging area 24l show a left stereoscopic part image while the right projection beam 23r is disabled. Subsequently, the control unit 20 the right light source 12r turn on and at the same time on the right imaging area 24r to represent a right stereoscopic partial image while the left projection beam 23l is disabled. The deactivation can z. B. by turning off the light source 23l or 23r be achieved. The switching frequency is preferably 120 Hz or more, to flicker the HUD image 18 to avoid and achieve a smooth dynamic representation.

The imaging display 14 here is an LCD display; In general, however, both transmissive displays, reflective displays and self-luminous displays can be used.

The imaging areas 24l respectively. 24r are via a dashed control line 27 from the control unit 20 driven. Both light sources 12l and 12r are via a dashed control line 28 from the control unit 20 controlled, in particular switched on and off.

The through the imaging areas 24l respectively. 24r passed through projection light beam 23l . 23r are applied with a respective stereoscopically-matched image and / or partial image and strike at a corresponding left reflection region 25l or right reflection area 25r on the mirror 15 on, then, such. In 2 sketched, bildvergrößernd to be deflected to the windscreen. The lenses 13l respectively. 13r and reflection areas 25l respectively. 25r the respective projection light beam 23l . 23r For example, they may be configured differently for light bundle-individual image correction.

The different partial images may also have a different predistortion, which take into account the different geometries of the paths of the two projection light bundles, for. B. with respect to a locally different curved and / or spaced surface of the windshield. Alternatively or additionally, the different images may be alternately displayed partial images of a 3D image.

4 shows in one too 3 analog representation, a second possible arrangement of the light sources 12r . 12l and the imaging display 14 a projection unit. Unlike the first, in 3 As shown arrangement, the projection light beams intersect 23l . 23r now in a common imaging area 24 of the imaging display 14 , This allows the imaging display 14 smaller and less expensive. An imprint of different images on the two projection light bundles 23l . 23r For example, by an alternating activation of the projection light beam 23l . 23r or the associated light sources 12l and 12r with a sufficiently high frequency, e.g. B. more than 120 Hz, and a synchronized circuit of the imaging area 24 be achieved. The imaging display 14 must now alternately the stereoscopic partial images for both projection light bundles 23l . 23r show and requires a correspondingly short switching time. As the projection light bundles 23l . 23r can cross, the right light beam 23r (ie, that of the right LED 12r generated light beams) illuminate the left eye or define the left eyebox, and analogously, the left light beam 23l light the right eye.

In order to reduce the time to build up a partial image, generally at least part of the stereoscopically different image information can be precalculated and currently accessed. As a result, at least part of the computation time otherwise required for image construction is avoided.

5 shows in one too 3 and 4 analog representation, a third possible arrangement of the light source (s) and the imaging display 14 a projection unit. While now similar to the first arrangement, the projection light beam 23l . 23r separated at different imaging areas 24l respectively. 24r through the imaging display 14 run, becomes a common light source 12 for generating the two projection light bundles 23l . 23r used. This light source 12 is a beam splitter 26 downstream of that of the light source 12 radiated light into the two projection light bundles 23l . 23r divides.

6 shows in one too 4 analog representation, a fourth possible arrangement of the light sources 12r . 12l and the imaging display 14 a projection unit, whereby now also the beam path continues up to the eyeboxes 21l . 21r is executed. The two LEDs 12l . 12r emit their respective projection light bundles 23l . 23r through a common condenser 13 to a common imaging area 24 of the imaging display 14 , If (only) the left LED 12l is switched on, the display shows 14 in his imaging area 24 the image for the left projection light beam 21l here illuminating the right eye. If (only) the right LED 12r is switched on, the display shows 14 in his imaging area 24 the image for the right projection light bundle 21r that illuminates the right eye here. The projection light bundles 23l . 23r are in the light source plane and in the eyeboxes 21l . 21r separated. There may be an overlap in the other levels.

Of course, the present invention is not limited to the embodiment shown.

Thus features of the embodiments can also be combined or suitably replaced. For example, an embodiment with a common light source according to the third arrangement is made 5 with the beam crossing of the second arrangement 4 possible.

Also, the light sources and the at least one imaging display can be controlled in another way. For example, the light sources can be run in a continuous operation, and the deactivation or dark switching of the associated projection light beam via an aperture o. Ä., Or via an at least substantially opaque black circuit of the associated imaging area.

The invention is further not limited to the use of light-emitting diodes or other semiconductor light sources.

The invention is not limited to the use of white light sources, but can, for. B. also have monochrome light sources. The light sources can be designed so that they can change their color.

The imaging display can be pixel-controllable and / or be segment-controlled. The imaging display can be monochrome or colored.

Other and / or more or less optical elements may be used. Thus, more than one optical element in the projection unit can be present behind the imaging display, z. B. two or more lenses and / or mirrors.

LIST OF REFERENCE NUMBERS

10

vehicle

11

projection unit

12l

left LED

12r

right LED

13

condenser

14

Imaging display

15

reflector

16

transparent cover

17

windscreen

18

HUD image

19

Head-Up Display

20

control unit

21l

left eyebox

21r

right eyebox

22

outer contour

23l

left projection light beam

23r

right projection light bunch

24

common imaging area

24l

Imaging area of the left projection light beam

24r

Imaging area of the right projection light beam

25l

Reflection area of the left projection light beam

25r

Reflection area of the right-hand projection light beam

26

beamsplitter

27

Control line for controlling the imaging areas

28

Control cable for controlling the light source (s)

Claims (15)

Method for generating an image ( 18 ) by a projection unit ( 11 ) for a head-up display ( 19 ), wherein the method has at least the following steps: generating at least two projection light bundles which do not overlap, at least in the eyebox ( 23r . 23r ); Generating different image information for the two projection light bundles ( 23r . 23r ); and - impressing the generated different image information on the two projection light bundles ( 23r . 23r ). The method of claim 1, wherein the method comprises at least the following steps: - generating at least two non-overlapping projection light bundles ( 23r . 23r ); Time-varying activation of the projection light bundles ( 23r . 23r ); Generating stereoscopically different image information for the projection light bundles ( 23r . 23r ); and - impressing the generated different image information on the projection light bundles ( 23r . 23r ). Method according to Claim 2, in which the projection light bundles ( 23r . 23r ) are activated alternately in time with a frequency of at least 120 Hz. Method according to one of the preceding claims, in which for impressing the generated different image information on the two projection light bundles ( 23r . 23r ) at least one light source ( 12 ; 12l . 12r ) and at least one associated imaging display ( 14 ; 24l . 24r ) of the projection unit ( 23r . 23r ) are controlled synchronously. The method of claim 1, wherein - The at least two projection light beams are generated by mutually different colored light sources and - The different image information for the two projection light beam is applied in different, matching the projection light bundles different color channels of the display. Method according to one of the preceding claims, in which at least part of the stereoscopically different image information is precalculated and is currently retrieved. Method according to one of the preceding claims, in which at least part of the stereoscopically different image information is actually calculated. Method according to one of the preceding claims, in which the stereoscopically different image information comprises an eye-dependent distortion correction. Projection unit ( 11 ) for a head-up display, which is set up for carrying out the method according to one of the preceding claims. Projection unit ( 11 ) according to claim 9, wherein the projection unit for generating each of the two at least in the eyebox not overlapping projection light beam ( 23r . 23r ) at least one respective light source ( 12l . 12r ) having. Projection unit ( 11 ) according to claim 9, wherein the projection unit ( 11 ) for generating the two non-overlapping projection light bundles ( 23r . 23r ) at least one common light source ( 12 ) and one of the common light source ( 12 ) optically downstream, temporally switchable beam deflection unit ( 26 ) having. Projection unit ( 11 ) according to one of claims 9 to 11, characterized in that the projection unit ( 11 ) for generating one of the projection light bundles ( 23r . 23r ) exactly one light source ( 12 ; 12l . 12r ) having. Projection unit ( 11 ) according to claim 12, characterized in that the exactly one light source has a light emitting diode, in particular an inorganic light emitting diode or a planar organic light emitting diode. Projection unit ( 11 ) according to one of the preceding claims, characterized in that the projection unit ( 11 ) at least one backlit image display ( 14 ) having. Vehicle ( 10 ) with a head-up display ( 19 ), with the head-up display ( 19 ) the projection unit ( 11 ) according to one of claims 9 to 14, in which a through the head-up display ( 19 ) generated image ( 18 ) on a windscreen ( 17 ) of the vehicle ( 10 ) is displayed.

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