EP1410096A2

EP1410096A2 - Projection arrangement

Info

Publication number: EP1410096A2
Application number: EP02754919A
Authority: EP
Inventors: Reinhold Fiess; Andreas Deter
Original assignee: Robert Bosch GmbH; Schneider Laser Technologies AG
Current assignee: Robert Bosch GmbH; LDT Laser Display Technology GmbH
Priority date: 2001-07-20
Filing date: 2002-07-19
Publication date: 2004-04-21
Also published as: JP2005500567A; JP4159466B2; WO2003016982A2; DE10135342C1; WO2003016982A3; AU2002321250A1

Abstract

The invention relates to a projection arrangement, comprising a projector unit (1) and a projection surface (2), whereby, in order to generate an image on the projection surface (2), the projector unit (1) illuminates the above with a light beam (5) for each image point of the image for generation. The projection surface (2) is provided with a mirror (11) and a beam divergent device (12), which, when viewed in the direction of the light beam (5), incident on the mirror, has the mirror (11) first, whereby the mirror (11) reflects all the beams of light coming from the projector unit (1), passing through the beam divergent device (12) and incident on the mirror (11), in such a way that at least one light beam (6), emerging after passing through the beam divergent device (12), is generated from a main ray (25). Main rays (25) for emergent light beams (6), emitted from adjacent areas of the projection surface (2) in a first direction, converge in an imaginary observed field (9), lying on a plane and the convergence of each emergent light beam (6), caused by the beam divergent device (12), is fixed such that the emergent light beams (6) each diverge and, in the plane, illuminate only the observed field (9).

Description

Proiektionsanordnung

The invention relates to a projection arrangement with a projector unit and a projection surface, the projector unit for generating an image on the projection surface illuminating it with a light bundle for each pixel of the image to be generated and the projection surface has a beam expansion device for expanding light bundles passing through it

Such a projection arrangement is known from DE 195 40 108 C2, this projection arrangement being arranged in a motor vehicle within the dashboard and having imaging optics arranged downstream of the projection surface, the object-side focal point of which lies between the projector unit and the beam expansion device Reflection on the windshield can be perceived by the viewer as a virtual image

Such a virtual, enlarged image on the windshield, however, requires a large amount of space within the dashboard due to the necessary imaging optics, but this is practically not available in a motor vehicle, since this space is provided, for example, by electrical lines for the display instruments and operating elements and by air supply for the ventilation is packed extremely tightly. The arrangement of the imaging optics in the area below the dashboard would necessitate extensive changes in the design of the motor vehicle. Furthermore, a very large opening in the dashboard is required for unobstructed light emission, which is not accepted for design reasons

Furthermore, a holographic projection surface for a vehicle is known from DE 197 30 563 A1. The radiation of the image information is intended to take place in an angle range which is predetermined and adjustable during the production of the hologram, towards the viewer, the holographic projection surface absorbing the ambient light and only the light for the image display With such a projection surface, the disadvantage is that the practically uncontrollable dependence of the properties of such a projection surface on the wavelength of the incident light bundle and the direction of incidence of the light bundle of the useful light proves to be furthermore the fact that the image is displayed and the appearance of the projection surface itself is very strong depending on the observation Proceeding from this, it is an object of the invention to develop a projection arrangement of the type mentioned at the outset in such a way that a high-quality image display can be achieved.

The object is achieved in a projection arrangement of the type mentioned at the outset in that the projection surface has a mirror and in that the beam expansion device, as seen in the direction of the light beam incident on the projection surface, is connected upstream of the mirror, the mirror coming from the projector unit through which Beam widening device passing through and hitting the mirror reflects such that at least one emerging light bundle passing through the beam widening device is produced with a main beam, the main beams coming from emerging light beams coming from locations (or locations on) that are adjacent in a first direction Go out projection surface, converge in an imaginary field of view lying in a plane, and wherein the widening caused by the beam expansion device of each emerging light beam is determined so that the emerging light beam del diverge in each case and no longer illuminate the field of view in the plane. Due to the reflection on the mirror and the widening of the emerging light bundles caused by the beam expansion device, it is advantageously achieved that almost all of the light energy reaches the field of view, so that the image brightness is extremely high. If the projection arrangement according to the invention is used in a means of transport, e.g. a motor vehicle, a contrast difference of up to 1: 500 can be achieved.

Furthermore, the construction of the projection arrangement is comparatively simple due to the projection area, as a result of which the projection arrangement can be implemented particularly cost-effectively.

Also, due to the directional characteristic of the projection surface and the resulting high image brightness, the energy consumption of the projection arrangement is extremely low and can be, for example, less than 50 watts.

In an advantageous development of the projection arrangement according to the invention, the projection surface is curved. The curvature can be different in different directions, and in particular the curvature can also be chosen such that the projection surface is, for example, corrugated. Regardless of the existing curvature of the projection surface, however, its directional characteristic is still given, so that the geometric shape of the projection surface can advantageously be selected independently of its optical properties. This can be used, for example, to ensure that the projection surface is in one when using the projection arrangement according to the invention Motor vehicle is adapted to the (curved) shape of the dashboard and is provided on this or as an integral part thereof. This fulfills the high demands placed on the design, particularly in motor vehicle construction.

In a preferred development of the projection arrangement according to the invention, the beam expansion device comprises a scattering layer, which can in particular be designed as a film. The desired widening of the emerging light bundles can be ensured in the simplest manner by means of the scattering layer. Such a scattering layer can be provided with a small air gap to or directly on the mirror, as a result of which an optimal image quality is achieved. The scattering layer can preferably have the same curvature as the projection surface, so that it can be made extremely compact.

Furthermore, it is still possible with the projection arrangement according to the invention that the intensity distribution of the emerging light bundles is determined by means of the beam expansion device so that the intensity of the main beam is greatest for each light bundle and decreases for the remaining light beams with an increasing angle relative to the main beam. Good image quality is achieved through this intensity distribution.

In particular, the beam expansion device can also comprise an aperture which shades incident light from directions other than the directions of the light bundles coming from the projector unit and as the directions of the emerging light bundles. Such an aperture ensures that the incident light bundles hit the mirror unhindered and the emerging light bundles can be seen by the viewer, while unwanted ambient light is shadowed and thus does not deteriorate the quality of the image display. Furthermore, when the projection arrangement is used in a motor vehicle, the screen also ensures that the projection surface is not perceived as a brightly lit surface from outside the vehicle. Furthermore, the panel can also be colored in the same color as that of the dashboard, so that the projection surface can be completely integrated optically in the dashboard.

In particular, such a diaphragm, viewed in the direction of the light beam incident on the projection surface, can be arranged upstream of the scattering layer. With this arrangement, the effect of the aperture is very effective. In a further development of the projection arrangement according to the invention, the diaphragm comprises a plurality of spaced-apart and mutually parallel slats which block light striking it. The diaphragm can also still have a plurality of spaced-apart and mutually parallel second lamellae, which open the they block the light that hits them and are arranged transversely to the first slats. Such screens with lamellae are described, for example, in US Pat. No. 6,239,911 B1 and are commercially available as foils, so that the projection arrangement according to the invention can be implemented in a simple manner.

Furthermore, in the projection arrangement according to the invention, the mirror can comprise a curved, continuous reflection layer. This can e.g. be realized by a mirrored surface of a carrier, the surface being designed as a continuously running free-form surface. The curvature of the free-form surface is chosen so that the convergent course of the main rays is effected for the corresponding image point in the case of specular reflection of the incident light beam.

Alternatively, it is also possible that, in the projection arrangement according to the invention, the mirror is designed as a multi-surface mirror with a multiplicity of flat mirror surfaces, it being possible for part of the scattering layer to be applied directly as a coating to each mirror surface. With such a multi-surface mirror, it is possible that the inclination of the mirror surfaces is determined independently of the desired curvature of the projection surface.

In particular, the mirror surfaces can be arranged such that the surface normals of at least two mirror surfaces are not parallel to one another. The arrangement is preferably selected such that the convergent course of the main rays is effected by means of the reflection. The directional characteristic of the projection surface can thus be set independently of a desired curvature of the projection surface, so that the projection surface can easily be adapted to predetermined framework conditions.

In a particularly preferred development of the projection arrangement according to the invention, the area of each mirror surface is smaller than the size of a pixel of the image to be generated on the projection surface, the improvement in image quality being very good when the number of mirror elements is twice the number of pixels , In this development, an incident light bundle can then generate a plurality of non-parallel, emerging light bundles due to the reflections of the incident light bundle on several mirror surfaces.

An advantageous development of the projection arrangement according to the invention is that the mirror is a rear surface mirror. In this case, contamination and a consequent deterioration of the image display are effectively prevented. Furthermore, the mirror in the projection arrangement according to the invention can comprise a transparent plate in which at least one side is structured in such a way that the direction of a light beam passing through the plate is changed. This ensures a particularly simple possibility of realizing the mirror. The plate can also be designed in such a way that, due to the change in direction caused by it, the convergent course of the main rays is brought about.

The side of the plate facing away from the beam expansion device is preferably structured and mirrored, so that the mirror can be realized in a compact manner by a single element. This also makes it possible to reduce the production costs of the mirror and thus of the projection arrangement according to the invention.

In the projection arrangement according to the invention, it is also possible for the main rays from emerging light bundles, which emanate from the neighboring locations of the projection surface in a second direction, to converge in the field of view due to the reflection on the mirror, the second direction being different from the first direction. In particular, the two directions can enclose an angle of 90 °. In particular, all the main rays of the emerging light bundles can converge in the field of view. These developments advantageously make it possible to increase the image brightness.

In particular, in the projection arrangement according to the invention, the projector unit can generate an intensity-modulated light beam and steer it over the projection surface in order to generate the image. This deflection of the light bundle can be grid-like (the deflection takes place line by line over the entire image area, the light bundle being keyed dark in the case of dark pixels) or vector-like (the deflection essentially only takes place along the bright pixels). This enables a simple way of generating the real image on the projection surface.

The light beam is preferably essentially collinear and can preferably have a beam product of less than 0.2 mm mrad (e.g. 0.1 mm mrad). Such a light beam can be generated particularly easily and efficiently with a laser, it being monochromatic or, for colored images, polychromatic.

In addition to the use of such a writing projector unit, it is also possible to provide image-imaging projector units in which, for example, the desired image can be generated by means of a tilting mirror matrix or an LCD module and can be projected onto the projection surface by means of projection optics. The projection assembly according to the invention can be used advantageously where an image having focused radiation to be radiated from a surface having a predetermined surface shape, since the projection surface of the projection arrangement according to the invention the predetermined surface shape can be formed in accordance with ^'.

This is particularly advantageous when the projection arrangement according to the invention is used in a motor vehicle, the projection surface preferably being formed on the dashboard or as a component thereof.

The projection arrangement according to the invention can be designed such that the real image on the projection surface can be directly grasped by the viewer. In this case, a very high quality representation of a real image is advantageously achieved.

Alternatively, the projection arrangement according to the invention can also have a reflection surface (preferably essentially flat) arranged downstream of the projection surface, on which the emerging light bundles are reflected such that the image generated on the projection surface can be captured as a virtual image. Therefore, the projection surface can advantageously be arranged so that it is not directly visible to the viewer, which means that the arrangement options of the

Projection area are increased.

When using the projection arrangement according to the invention in a motor vehicle, the reflection surface can be realized particularly simply through the windshield (or also through a windshield arranged in the vehicle directly in front of the windshield, which is preferably flat). Since the image can be generated on the projection surface in the desired size, there is advantageously no imaging optics between the projection and the

Reflective surface necessary.

In this case, it is of particular advantage that this virtual image can be captured in the scene image by the viewer in front of the windshield (and thus outside the vehicle), so that the viewer or the driver's eyes are only slight when viewing the virtual image must accommodate.

Under certain circumstances, the curvature of the windshield provides a small change in the image dimensions, whereby the geometric corrections of the image known from an oblique projection, such as e.g. is described in DE 197 37 374 C2, can be carried out.

In the projection arrangement according to the invention, the expansion of the emerging light bundles is preferably effected isotropically, so that the beam expansion device can be designed in a particularly simple manner. When using the invention Projection arrangement in a motor vehicle, the divergence angle of the emerging light bundles can be 2 to 10 ° in space conditions, as are typical in a motor vehicle, a divergence angle of 5 ° having proven to be particularly advantageous. It is of course also possible for the widening of the emerging light bundles to be effected anisotropically, for example if the field of view is to have different widths and heights.

Furthermore, the reflection layer of the mirror, on which the specular reflection takes place, can be structured such that the function of the beam expansion device is also effected during the reflection. Such a mirror can be produced, for example, by molding the desired surface structure into a surface of a plate and then mirroring the structured surface.

The invention is explained in more detail below by way of example with reference to the drawings. From the figures show:

1 shows a side view of an embodiment of the projection arrangement according to the invention; Fig. 2 is an exploded view of an enlarged section of that shown in Fig. 1

Projection screen; Fig. 3 is a side view of the embodiment of Fig. 1, with ray traces being drawn in for explanation;

FIG. 4 shows the embodiment of FIG. 3 from the driver's perspective;

Fig. 5 is an enlarged sectional view of a section of that shown in Fig. 3

Projection screen; 6 shows an embodiment of the mirror of the projection surface; 7 shows a further embodiment of the mirror of the projection surface;

Fig. 8 is a side view of another embodiment of the invention

Projection device; 9 shows a side view of a further embodiment of the projection arrangement according to the invention, and FIG. 10 shows a side view of yet another embodiment of the projection arrangement according to the invention.

1 shows a side view of an embodiment of the projection arrangement according to the invention, which is installed in a motor vehicle and comprises a projector unit 1 and a projection surface 2. The projector unit 1 is arranged in the roof area within the motor vehicle close to its windshield 3 and the projection surface 2 is mounted on a dashboard 4, the shape of the projection surface 2 being the shape that is usually in different directions is differently curved, the dashboard 4 is adapted It is of course also possible that the projection surface 2 is formed as an integral part of the dashboard 4 and it can typically have a size of 35 cm in width and 10 cm in height

The projector unit 1 generates an intensity-modulated, essentially parallel light bundle 5, which, as shown schematically in FIG. 1, directs it over the projection surface 2 in order to set a real image thereon. The projection surface 2 emits the light coming from the projector unit 1 as an emerging light bundle 6 only in a predetermined area 7 towards the driver 8 so that the driver can capture the real image on the projection surface 2 when he is sitting in the driver's seat of the vehicle

On the basis of this predetermined radiation property of the projection surface 2, the image on the projection surface 2 is only visible for any distance from the projection surface within a viewing field lying in one plane, the viewing field 9 being shown directly in the area of the driver's eyes 10 in FIG. 1

The size of the field of view 9 is determined by the radiation characteristics of the projection surface 2, the radiation characteristics being set by the measures described in detail below so that drivers 8 with different body sizes can see the image on the projection surface 2. In addition, the usual range of movement of the head ( and thus the range of movement of the eyes) is taken into account, so that here the square field of view 9 has an extension of approximately 30 x 30 cm at a distance of approximately 800 mm from the projection surface 2

In order to produce the desired radiation characteristic of the projection surface 2, it comprises, as can be seen from the exploded view of a section of the projection surface 2 in FIG. 2, a multifaceted mirror 11 on which a beam expansion device 12 with a scattering layer 13 and a blind cover 14 is applied

The multi-surface mirror 11 of the projection surface 2 serves to locally reflect the incident light bundles 5 of the projector unit 1 locally, while the diffusion layer 13 is provided for the desired beam expansion of the reflected bundle 6. The blind panel 14 can, if necessary, limit the through the scattering layer 13 caused by the beam expansion are also used to prevent undesired ambient conditions from striking the multifaceted mirror 11 and worsening the image display and that the real image is visible to third parties. The multipurpose mirror 11, the scattered layer 13 and the blind aperture 14 are optimized with regard to their optical tasks The multi-surface mirror 11 thus comprises a PMMA plate 15 (PMMA = polymethyl methacrylate), the surface of which facing the scattering layer 13 is structured and mirrored. The structuring is carried out in such a way that a multiplicity of microprisms 16 are formed, one prism surface in each case being used as a flat mirror surface 17. By specifically designing the microprisms 16, it is possible to set the inclination of the mirror surfaces 17 completely independently of one another and also within wide limits independently of the geometric (macroscopic) shape of the projection surface 2. With a known or predetermined shape of the projection surface 2, the setting is set such that the light beams reflected on the mirror surfaces 17 are reflected only in the spatial region 7, as will be described in detail below.

The scattering layer 13 is designed as a film which lies directly above the multifaceted mirror 11 and has the effect that the angle of divergence (half the opening angle of the light beam) of a light beam passing through the scattering layer 13 is increased, as indicated in FIG. 2 by the scattering lobe 18 shown. The widening caused by the scattering layer 13 is selected here so that the divergence angle of the emerging light beam 6 is in the range from 2 to 10 °. For example, a holographic diffuser from POC Physical Optics Corporation, Torrance, Canada, can be used as the diffusion layer 13, which advantageously has a relatively high degree of transmission independence for the wavelengths used here.

On the scattering layer 13, a blind cover 14 is applied, which is designed as a film and has a plurality of spaced-apart and mutually parallel slats 19 which absorb light falling on them. The distance between the slats 19, their inclination in the film and their height can limit the angular range of the incoming and outgoing light transversely to the slats 19, the Venetian blind 14 being designed such that the incoming and outgoing light beams 5, 6 can pass the blind cover unhindered. The shutter 14 prevents, in particular, that external light (eg sunlight and interior lighting) which strikes the projection surface 2 undesirably is perceived by the driver 8 on the projection surface 2. Furthermore, the blind panel 14 can be colored in the same color as that of the dashboard 4, so that the outer appearance of the projection surface 2 is adapted to that of the dashboard 4. In addition, the shutter 14 also prevents the projection surface 2 from appearing outside the vehicle as a luminous surface. Such a Venetian blind film 14 with desired properties (such as the slat inclination) can be obtained, for example, from 3M. As can best be seen from the side view of FIG. 3, the projector unit 1 contains three laser light sources 20, 21, 22, each of which emits an intensity-modulated collinear (or essentially collinear) light beam in one of the primary colors red, green and blue , a beam merging unit 23, which overlays the three light beams of the laser light sources 20, 21 and 22 to form a common red-green-blue light beam, which then uses a biaxial deflection system 24 of the projector unit 1 in a row direction (parallel to the windshield 3) and one vertical column direction is rastered over the projection surface 2. The deflection angle in the column direction is φ, and, as shown in FIG. 4, which shows a view from the driver's point of view 8, the deflection angle in the row direction is φ, the beam path for different pixels P1, P2, P3, P4, P5 and P6 is shown on the projection surface 2 (with the points P1-P3 in the column direction and the points P4-P6 in the row direction adjacent). The image size is determined by the size of the angles φ and φ and by the distance of the deflection system 24 from the projection surface 2. In the example described, the distance is approximately 700 mm and cp = 4 ° and φ = 28 °, so that an image size of approximately 10 x 35 cm results. If the angles <p and φ are predetermined by the deflection system 24 and do not lead to the desired image size on the projection surface 2 (for example due to the projection distance determined by the installation conditions), the deflection system can have a known transformation optics (not shown) in the beam path, with which the desired adjustment of the deflection angle and thus the image size can be carried out.

3, the essentially collinear light beam 5, the beam product of which is smaller than 0.2 mm mrad (for example 0.1 mm mrad) and which is directed onto the projection surface 2 to generate the pixels P1 to P6, radiated from the projection surface 2 in each case as a divergent light bundle 6 with a main beam 25 (the main beam 25 is the beam which is generated due to the specular reflection without the beam expansion and thus in accordance with the law of reflection (angle of incidence is equal to the angle of reflection)), all main beams 25 in Eye point 26 converge in the field of view 9 or in a spatial area enclosing the eye point 26. This is achieved in that the corresponding mirror surface 17 is inclined for each of the pixels P1 to P6 in such a way that the main rays 25 are deflected towards the eye point 26 when the incident light bundle 5 is reflected.

The inclination of the mirror surfaces 17 is thus set as a function of their local position in the projection surface 2, their distance from the eye point 26 and the angle of incidence of the light beam 5 striking them in accordance with the law of reflection. In FIG. 3 the optical plumb 27 is shown for the pixel P2 and in FIG. 4 the optical plumb 27 'is shown for the pixel P5. If one further assigns a macroscopic surface normal 28 for the pixel P2 and a macroscopic surface normal 28 'for the pixel P5 to the projection surface 2, as can be seen in FIGS. 3 and 4, it can be seen that the optical direction in both the row and the column direction Lot 27, 27 'and the surface normal 28, 28' are inclined differently. The angles γ and δ that they enclose are shown in FIGS. 3 and 4. It can be seen from this that the (macroscopic) surface shape of the projection surface 2 can be selected independently of the desired direction of the reflected light bundles 6. It is therefore possible to produce the desired optical properties of the projection surface 2 as largely as possible regardless of the shape (or curvature) of the projection surface 2.

Furthermore, the light bundle reflected on the mirror surfaces 17 is expanded by the scattering layer 13 such that the divergence angle gen of the emerging light bundle 6 in the column direction and the divergence angle τ in the row direction each assume a predetermined value. These values result from the distance of the field of view 9 from the projection surface 2 and are chosen such that the diverging light beams 6 only illuminate the field of view 9.

Since in the example described here the distance between the driver 8 and thus the field of view 9 from the projection surface 2 is approximately 800 mm and the field of view should have an extension of 20 x 20 cm, the divergence angles Θ, τ of the emerging light bundles 6 are each preferably approx 5 °, whereby the expansion by means of the scattering layer 13 takes place isotropically, so that the divergence angles Θ, τ are the same.

It is of course also possible that the two divergence angles Θ and τ have different values. In this case, the extent of the field of view in the row and column direction is also different.

3 and 4, the scattering lobes 18 for the outgoing light bundles 6 are also shown. From the scattering lobes 18 it can be seen that the image brightness is highest in the center of the field of view 9 and decreases towards the edges, the decrease starting from the center being initially relatively small and then decreasing very sharply in the edge region. This results in a relatively good uniformity of the image brightness over the entire field of view.

The directional radiation characteristic of the projection surface 2 advantageously also ensures that almost all of the light energy used for the projection is imaged into the field of view 9 and thus into the range of motion of the eyes 10. Thereby A sufficient brightness of the projected image can be brought about so that the image can be easily recognized by the driver 8 even in daylight.

5 shows a section of the projection surface 2, enlarged, in a sectional illustration. As can be seen in FIG. 5, the projection surface 2 generates an emerging light bundle 6 with the main beam 25 from each incident light bundle 5, the direction of which is determined on the basis of the specular reflection on the mirrored microprism surfaces 17. The divergence angle Θ, τ of the emerging light bundle 6 is set by the diffusion layer 13, whereby, in the example shown in FIG. 5, the blind aperture 14 also contributes to the limitation of the divergence angle, since it causes the scattered rays to form one large divergence angle would be absorbed. With the Venetian blind 14, the divergence angle of the emerging light bundles 6 generated by means of the diffusion layer 13 can be specifically reduced.

6 shows another possible implementation of the multi-surface mirror 11 in an exploded view. The multi-surface mirror 11 comprises a first and a second PMMA plate 29, 30. On the surface of the first plate 29, parallel grooves 31 are formed which have a V-shaped cross section (as shown in the enlarged detail). This surface is mirrored, so that flat mirror surfaces 17 with an angle of attack of 40 ° are provided. The second PMMA plate 30 has a flat side 30 'facing the first PMMA plate 29 and an opposite second side 32 which comprises a plurality of parallel grooves 33 with a V-shaped cross section, a first side of the V -shaped cross section is almost perpendicular to the flat side 30 'and the other side of the V-shaped cross section, which serves as the optical active surface 34, forms a smaller angle with the flat side 30' than the first side. Furthermore, the angle of inclination of the active surfaces 34 of the grooves 33 increases from the center M of the second plate 30 to the outside in the direction transverse to the groove direction on both sides. The second PMMA plate 30, the effect of which corresponds to that of a cylindrical lens, is applied to the first PMMA plate 29 such that the grooves 33 run transversely to the grooves 31. As a result, the deflection of the emerging light bundle 6 is generated on the one hand by the refraction in the second plate 30 and on the other hand by the reflection on the first plate 29.

With the multi-surface mirror shown in FIG. 6, the convergence of the main rays 25 is effected only for outgoing light bundles 6, which originate from locations of the projection surface which are adjacent in the groove direction of the grooves 31, while the main rays of the light bundles 6, which come from locations adjacent in the direction transverse to the groove direction can go out, run parallel or divergent. In this case, the widening of the emerging light beams in this direction is selected so that the light beams still overlap in the area of the eyes 10. FIG. 7 shows a further possible embodiment of the multi-surface mirror 11, a groove structure having a V-shaped cross section having grooves 36 being formed on the underside of a PMMA plate 35 and the groove structure being mirrored. One of the PMMA is on the top of the plate 35 Plate 30 corresponding grooved structure applied so that the multi-surface mirror 11 is designed as a rear surface mirror

Another embodiment of the projection arrangement according to the invention is shown in FIG. 8. This differs from the embodiment shown in FIG. 1 in that the projector unit 1 is no longer installed in the roof area of the motor vehicle, but rather inside or behind the dashboard 4

The light bundles 5 emitted by the projector unit 1 run essentially parallel to the windshield 3 and meet a deflection mirror 37 arranged in the roof area within the motor vehicle close to the windshield 3, at which they are reflected so that they in turn run essentially parallel to the windshield 3 and hit the projection surface 2. The deflection mirror 37 can be adjusted and fixed in its position in order to adjust the image position as desired by the driver. It is preferably only used for folding the beam path. As a result, the projector unit 1 can be arranged in the dashboard 4, which means that the space required for the projection arrangement of the interior of the vehicle accessible to the driver is only determined by the (small) deflection mirror 37

The installation space for the deflecting mirror 37 can be covered, for example, by the rear-view mirror 38. If, as shown in FIG. 8, a cover 39 is also applied to the windshield 3, the deflecting mirror 37 is also not recognizable from outside the vehicle. This concealing the deflecting mirror 37 is possible in the same way for the projector unit 1 in the embodiment shown in FIG. 1

A further embodiment of the projection arrangement according to the invention is shown in FIG. 9, in contrast to the previously described embodiments the projection surface 2, in particular the blind panel 14, is designed such that the projection surface 2 cannot be viewed directly by the driver 8. The driver 8 sees the image of the real (intermediate) image generated on the projection surface 2 reflected on the inside 40 of the windshield 3, so that for the driver 8 a (virtual) image 41 of the real intermediate image generated on the projection surface 2 in front of the windshield 3 in Real scene image appears. The remaining elements of the projection arrangement of FIG. 9 essentially correspond to those of the embodiment shown in FIG. 1 and are therefore identified by the same reference numerals In particular when using a projector unit 1 with laser light sources, the existing degree of reflection of the glass-air interface leads to a sufficiently bright image impression. Known measures, such as, for example, a broadband reflection increase on the inner surface 40 of the windshield 3, can be carried out in order to suppress a ghost image which can arise as a result of reflection at the outer interface of the windshield 3.

In the embodiment shown in FIG. 9, a panel 42 can still be provided in the area of the dashboard 4 on the inside 40 of the windshield 3, so that the projection surface 2 is not visible from the outside.

A projection arrangement which has been modified somewhat in comparison to the embodiment shown in FIG. 9 is shown in FIG. 10, the projector unit 1 now not in the roof area of the motor vehicle but within the dashboard 4 (in the same way as in the projection arrangement of FIG. 8). is arranged. In addition, the deflecting mirror 37 is arranged in the roof area of the motor vehicle between the rear view mirror 38 and the aperture 39. The light beams 5 emitted by the projector unit 1 run essentially parallel to the windshield 3 and meet the deflection mirror 37, which then reflects them back onto the projection surface 2, the light beams 6 emanating therefrom being reflected on the inside 40 of the windshield 3 in such a way that in turn A virtual image 41 is visible to the driver 8, which is located outside the motor vehicle in front of the windshield 3 in the real scene image.

In addition to the embodiments described so far, it is of course also possible to use the projector unit 1 in other areas of the roof area or in the area of the lateral border of the windshield 3, such as to arrange the A-pillar so that it can project obliquely onto the projection surface 2 or provide necessary deflecting mirrors if necessary.

Claims

Expectations

1 projection arrangement with a projector unit (1) and a projection surface (2), the projector unit (1) for generating an image on the projection surface (2) illuminating it with a light beam (5) for each pixel of the image to be generated, and wherein the projection surface (2) has a beam expansion device (12) for expanding light bundles passing through it, characterized in that the projection surface (2) comprises a mirror (11) and the beam expansion device (12), in the direction of the light beam (5) incident on the projection surface seen, the mirror (11) is connected upstream, the mirror (1 1) reflecting each beam of light coming from the projector unit (1), passing through the beam expansion device (12) and hitting the mirror (1 1), so that at least one through the beam widening device (12) passing, falling light bundle (6) with a main beam (25) is generated , the main rays (25) of emerging light bundles (6), which emanate from locations of the projection surface (2) adjacent in a first direction, converge in an imaginary viewing field (9) lying in one plane, and wherein the rays expanded by the beam expansion device ( 12) conditional expansion of each failing light bundle (6) is determined in such a way that the failing light bundles (6) each diverge and do not illuminate more than the field of view (9) in the plane

2 projection arrangement according to claim 1, characterized in that the projection surface (2) is curved

3 projection arrangement according to claim 1 or 2, characterized in that the beam expansion device (12) comprises a scattering layer (13)

4 projection arrangement according to claim 3, characterized in that the scattering layer (13) is applied to the mirror (11)

5 projection arrangement according to one of claims 1 to 4, characterized in that the beam expansion device (12) comprises an aperture (14), the incident light from others

Shades directions as the directions of the light bundle (5) coming from the projector unit (1) and as the directions of the outgoing light bundle (6), the diaphragm (14) is preferably arranged such that it, viewed in the direction of the light bundle (5) incident on the projection surface (2), is connected upstream of the scattering layer (13).

6. Projection arrangement according to claim 5, characterized in that the diaphragm (14) comprises a plurality of spaced and mutually parallel slats (19) which block light striking them.

7. Projection arrangement according to claim 6, characterized in that the diaphragm further comprises a plurality of spaced and mutually parallel second slats which block light striking them and are arranged transversely to the first slats (19).

8. Projection arrangement according to one of claims 1 to 7, characterized in that the mirror comprises a curved continuous reflection layer.

9. Projection arrangement according to one of claims 1 to 8, characterized in that the mirror (11) is designed as a multi-surface mirror with a plurality of flat mirror surfaces (17).

10. Projection arrangement according to claim 9, characterized in that the mirror surfaces (17) are aligned such that the surface normals of at least two mirror surfaces (17) are not parallel to one another.

11. Projection arrangement according to claim 9 or 10, characterized in that the mirror surfaces (17) are aligned so that the convergent course of the main rays is achieved by means of the reflection.

12. Projection arrangement according to one of claims 9 to 11, characterized in that the area of each mirror surface (17) is smaller than the size of a pixel of the image to be generated on the projection surface (2).

13. Projection arrangement according to one of claims 8 to 12, characterized in that the mirror (11) comprises a transparent plate (30, 35), in which at least one side is structured such that the direction of a through the plate (30, 35 ) light beam passing through it is changed.

14. Projection arrangement according to claim 13, characterized in that the convergent course of the main rays is achieved due to the change in direction caused by the plate (30, 35).

15. Projection arrangement according to claim 13 or 14, characterized in that the side of the plate (35) facing away from the beam expansion device is structured and mirrored.

16. Projection arrangement according to one of claims 1 to 15, characterized in that the main rays (25) from outgoing light bundles (6) emanating from adjacent locations of the projection surface (2) in a second direction, due to the reflection on the mirror (11) converge in the field of view (9), the second direction being different from the first direction.

17. Projection arrangement according to one of claims 1 to 16, characterized in that all the main rays (25) of the emerging light bundle (6) converge in the field of view (9).

18. Projection arrangement according to one of claims 1 to 17, characterized in that the projector unit (1) generates an intensity-modulated light beam and steers over the projection surface (2) to produce the image.

19. Projection arrangement according to one of claims 1 to 18, characterized in that one of the projection surface (2) downstream reflection surface (3) is arranged so that the emerging light bundles (6) are reflected on this and thus on the projection surface (2) generated image can be captured as a virtual image.

20. Projection arrangement according to one of claims 1 to 19, characterized in that the mirror and the beam expansion device are integrally formed.