Projection unit of or for a vehicle, vehicle component comprising such a projection unit, and vehicle

Abstract

The invention relates to a projection unit (491, 492, 493) of or for a vehicle (48), comprising: a light source (12); a reflective microdisplay (32) for reflecting the light emitted by the light source (12); a first lens unit (14) for collecting light emitted by the light source (12) along a first axis (A1); a reflector (28) for guiding the light collected by the first lens unit (14) along a second axis (A2) to a reflective microdisplay (32); a second lens unit (38) for collecting the light reflected by the reflective microdisplay (32) and for guiding the collected light to the projection surface (42) wherein the reflective microdisplay (32) is arranged inside the projection unit (491, 492, 493), the reflective microdisplay (32) being rotated by a rotation angle (alpha) such that the row direction (DR) and / or the column direction (DC) is inclined with respect to the first axis (A1). Furthermore, the invention relates to a vehicle component (44) and / or a vehicle (48) comprising such a projection unit (491, 492, 493).

Description

Technical Field

[0001] The invention relates to a projection unit for a vehicle or for a vehicle. The invention also relates to a vehicle component and / or a vehicle comprising such a projection unit. Background Art

[0002] Projecting images onto a projection surface of the vehicle or onto a projection surface near the vehicle is becoming increasingly popular in modern vehicles. Such images can be used as inspirational features for attracting customers. An inspirational feature can be that when the vehicle is unlocked by the driver or owner, a specific image is projected onto a given projection surface. Such an image can be projected onto the ground next to the vehicle.

[0003] However, such projections can also be used to convey information to other road users. As an example, a warning message indicating slippery, icy or traffic jams on a given road can be displayed to avoid accidents. Such warning messages can be displayed on the outer surface of the vehicle to be well visible to other road users.

[0004] Such an image is generated by a projection unit which often comprises a digital projector and which is typically integrated into a vehicle component or otherwise fastened to a given vehicle. Typical vehicle components into which a projection unit may be integrated may be side mirrors, door sills, etc. In such vehicle components, the available space is often limited. The required construction space for integrating a conventional projection unit is often greater than the available space in a given vehicle component, thereby hindering integration. Summary of the invention

[0005] An object of one exemplary embodiment of the present invention is to provide a projection unit for projecting images onto a projection surface of a vehicle or adjacent to the vehicle which requires less installation space than known projection units.

[0006] Furthermore, it is an object of embodiments of the present invention to provide a vehicle component and / or a vehicle comprising such a projection unit.

[0007] This object is achieved by the features specified in claim 1, 10 or 11. Advantageous embodiments are subject matter of the dependent claims.

[0008] One embodiment of the present invention is directed to a projection unit for a vehicle or for a vehicle, comprising:

[0009] -light source,

[0010] - a reflective microdisplay, the reflective microdisplay being used to reflect light emitted by a light source, comprising

[0011] ○ micro-reflective elements arranged in a matrix,

[0012] o the matrix is ​​defined by at least two rows extending in a row direction and at least two columns extending in a column direction,

[0013] ○ The row and column directions extend perpendicular to each other,

[0014] - a first lens unit for collecting light emitted by the light source along a first axis,

[0015] - a reflector for directing the light collected by the first lens unit to the reflective microdisplay along the second axis,

[0016] a second lens unit for collecting light reflected by the reflective microdisplay and for directing the collected light to the projection surface, wherein

[0017] The reflective microdisplay is arranged inside the projection unit, and the reflective microdisplay is rotated by a rotation angle such that the row direction and / or the column direction is tilted relative to the first axis.

[0018] In the following description, a rotation of 90° and integer multiples thereof is not considered to cause a tilt.

[0019] The image to be projected onto a projection surface of or near the vehicle should have a specific orientation relative to the vehicle axis. For example, the image projected onto the surface below the vehicle's side-view mirror should be parallel or perpendicular to the longitudinal vehicle axis. For this reason, the projection units known from the prior art also need to be arranged parallel or perpendicular to the longitudinal vehicle axis. When integrated into the side-view mirror, such an arrangement is almost impossible, mainly for the following reasons: the side-view mirror typically only provides limited available space. In addition, the side-view mirror is typically a curved component, which means that even if the available space allows the integration of the projection unit, an arrangement perpendicular or parallel to the longitudinal vehicle axis is impossible. A tilted arrangement will lead to distortions of the projected image.

[0020] According to the present disclosure, a reflective microdisplay is arranged inside a projection unit, and the reflective microdisplay is rotated by a rotation angle so that the first row direction and / or the second row direction is tilted relative to the first axis. The rotation of the reflective microdisplay makes it possible to project an image in a desired orientation with reference to the longitudinal vehicle axis, although the first axis extends neither parallel nor perpendicular to the longitudinal vehicle axis, wherein the light emitted by the light source is collected along the first axis. The first axis typically determines the orientation of the entire projection unit. Therefore, the projection unit according to the present disclosure can be integrated into a given vehicle component regardless of the required orientation relative to the longitudinal vehicle axis. The reflective microdisplay is rotated accordingly so that the image projected on the surface of the vehicle or near the vehicle has the desired orientation and is not distorted.

[0021] The light source may include one or more LEDs and / or laser sources.The reflective microdisplay may include micro-LEDs, organic light emitting diodes (OLEDs), or active matrix OLEDs (AMOLEDs), to name a few.

[0022] According to another embodiment, the reflector is arranged inside the projection unit, and the reflector rotates so that the light reflected by the reflector is completely irradiated on the reflective microdisplay. In the case where the reflective microdisplay rotates but the orientation of the other components of the projection unit remains unchanged, part of the light reflected by the reflector will not be irradiated on the reflective microdisplay, thereby reducing the light intensity. This may lead to a degradation in the quality of the correctly oriented image displayed on the projection surface. In extreme cases, parts of the image may be cut. However, in this embodiment, the reflector is arranged inside the projection unit so that all the light reflected by the reflector is irradiated on the reflective microdisplay. Thereby, the quality of the projected image is improved. The angle of rotation of the reflector can be the same as the angle of rotation of the reflective microdisplay. However, other arrangements are possible.

[0023] In yet another embodiment, the light source and / or the first lens unit are arranged inside the projection unit, and the light source and / or the first lens unit are rotated so that the light irradiated on the reflective micro display has a uniform light distribution. The uniform light distribution further improves the quality of the projected image. The angle of rotation of the reflector can be the same as the rotation angle of the reflective micro display.

[0024] In another embodiment, the reflective microdisplay is implemented as a liquid crystal on silicon element. Such microdisplay elements are also abbreviated as LCoS. They are widely used in digital projectors and are therefore available in large quantities. Their reliability has been proven.

[0025] A further embodiment requires that the first lens unit comprises a pre-polarizer and that the reflector is formed by a polarizing beam splitter. A certain property of LCoS is that the extent to which they reflect light depends on the angular orientation of the light waves, which have, for example, a maximum value of 180° and minimum values ​​at 90° and 270° respectively. The pre-polarizer only allows light to pass through at a given polarization angle. Depending on the polarization angle, the polarizing beam splitter reflects light to the LCoS or allows it to penetrate. Areas of light directed to the LCoS result in bright pixels at the projected image, while areas of transmitted light result in dark pixels, thereby producing at least a monochrome image.

[0026] According to another embodiment

[0027] - a pre-polarizer polarizes the light into a first polarization plane and a second polarization plane,

[0028] - the first polarization plane and the second polarization plane extend perpendicularly to each other,

[0029] A prepolarizer is arranged in the projection unit, the prepolarizer being rotated so that the first polarization plane extends parallel or perpendicular to the row direction.

[0030] The term "pre-polarizer" refers to its arrangement relative to the polarizing beam splitter and / or the reflective microdisplay.

[0031] In this embodiment, the pre-polarizer is tilted in a fixed relationship relative to the reflective microdisplay. Thus, polarized light impinges on the reflective microdisplay such that it is minimally or maximally reflected. Thus, the quality of the image displayed on the projection surface is improved.

[0032] Yet another embodiment requires that the second lens unit comprises a rear polarizer. The term "rear polarizer" refers to its arrangement relative to the polarizing beam splitter and / or the reflective microdisplay. The image leaving the polarizing beam splitter is polarized again, thereby further improving the quality of the image displayed on the projection surface.

[0033] According to another embodiment, the reflective microdisplay is implemented as a digital micromirror device. In this case, the reflective microdisplay is not implemented as an LCoS, but rather as a digital micromirror device (DMD), sometimes also referred to as digital light processing (DLP). Compared to LCoS, the light does not have to be polarized, resulting in a better light output. In addition, since no polarizer is required, the number of components can be reduced.

[0034] A further embodiment is characterized in that the reflector is formed by a prism. The prism can redirect light as required to the digital micromirror device using only one component. Therefore, the projection unit according to this embodiment can be compact.

[0035] A further aspect of the invention relates to a vehicle component comprising a projection unit according to one of the preceding embodiments.

[0036] A further aspect of the invention relates to a vehicle comprising a vehicle component according to one of the previously presented embodiments and / or according to the previously discussed embodiments of the projection unit.

[0037] The technical effects and advantages discussed with respect to the present projection unit also apply at least to a large extent to vehicle components and vehicles. In short, the projection unit can be arranged so that it fits the available space of a given vehicle component without compromising the desired orientation of the projected image relative to, for example, the longitudinal axis of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention is described in detail with reference to the accompanying drawings, in which:

[0039] Figure 1A shows a schematic side view of a projection unit according to the prior art,

[0040] Figure 1BThe vehicle components are shown arranged inside Figure 1B The principle top view of the projection unit shown in FIG.

[0041] Figure 1C Shown includes along Figure 1B Principle top view of a vehicle with projection units arranged inside vehicle components,

[0042] Figure 2A shows a principle top view of a first embodiment of a projection unit according to the present invention,

[0043] Figure 2B is a schematic diagram showing details about polarized light,

[0044] Figure 2C yes Figure 2A Schematic isometric view of the projection unit,

[0045] Figure 2D Shown includes along Figure 2C Principle top view of a vehicle with projection units arranged inside vehicle components,

[0046] Figure 3 is a principle isometric view of a second embodiment of a projection unit according to the invention, and

[0047] Figure 4 is a principle isometric view of a third embodiment of a projection unit according to the invention. DETAILED DESCRIPTION

[0048] Figure 1A A projection unit 10 known from the prior art for generating an image is shown. The projection unit 10 comprises a light source 12 for emitting light, which is in particular embodied as an LED and / or a laser source. The number of light sources 12 can be freely selected. In particular, light sources 12 emitting light of different colors can be used. Furthermore, the projection unit 10 is equipped with a first lens unit 14, which in the illustrated embodiment comprises a condenser lens 16, a lens array 18, in particular a microlens array 18 (MLA) or a cylindrical lens array 18 (CLA). The first lens unit 14 is also equipped with a Fourier lens 20, which is alternatively embodied as a relay lens. The first lens unit 14 can be provided with additional optical elements, not shown. Furthermore, the first lens unit 14 comprises a prepolarizer 22, which polarizes the light so that its electromagnetic waves extend within a first polarization plane 24 and within a second polarization plane 26, the first polarization plane 24 extending perpendicularly to the second polarization plane 26 (see also Figure 2B). Light extending in the first polarization plane 24 is also referred to as P-polarized light, and light extending in the second polarization plane 26 is referred to as S-polarized light. The prepolarizer 22 is the last element of the first lens unit 14 as seen from the light source 12 .

[0049] The first lens unit 14 collects and collimates the light rays emitted by the light source 12 so that they extend parallel to or along the first axis A1 .

[0050] The projection unit 10 is further provided with a reflector 28, which redirects light leaving the first lens unit 14 along or parallel to the second axis A2. In Fig. 1, the second axis A2 extends perpendicularly to the first axis A1. The reflector 28 is implemented as a polarization beam splitter 30 (PBS), which reflects P polarized light and transmits S polarized light, or vice versa.

[0051] refer to Figure 1A , a reflective microdisplay 32 is arranged above the polarizing beam splitter 30. The reflective microdisplay 32 includes a plurality of microreflective elements 34 arranged in a matrix. The matrix is ​​defined by a plurality of rows 37 and a plurality of columns 39. The rows 37 extend along a row direction DR, and the columns 39 extend along a column direction DC. The row direction DR is perpendicular to the column direction DC and parallel to the first axis A1 (see Figure 1B ).

[0052] The reflective microdisplay 32 is implemented as a liquid crystal on silicon element 36 , also referred to as LCoS 36 .

[0053] Assuming that the polarization beam splitter 30 reflects P-polarized light and transmits S-polarized light, only P-polarized light will be directed to the LCoS 36. Each individual micro-reflection element 34 can be switched between a first state and a second state. In the first state, the P-polarized light is reflected. In the second state, the P-polarized light is converted into S-polarized light. The P-polarized light reflected by the LCoS 36 will also be reflected by the polarization beam splitter 30 in a direction parallel to the first axis A1, and thus reflected toward the first lens unit 14 and the light source 12. However, the light converted into S-polarized light can pass through the polarization beam splitter 30 and thus enter the second lens unit 38, which includes a total of three lenses 40, however, a different number of lenses 40 may be used. Other optical elements (not shown) may also be provided in the second lens unit 38.

[0054] As a result, an image consisting of bright pixels and dark pixels is formed, wherein each pixel is defined by one of the micro-reflective elements 34. The monochromatic image leaving the second lens unit 38 is projected onto a projection surface 42 of or beside the vehicle 48 (see Figure 1C ).

[0055] As mentioned initially, more than one light source 12 may be used. In particular, light sources 12 emitting light of different colors may be used. In substantially the same manner as previously described, a multi-color image may be generated.

[0056] Figure 1B Shows Figure 1A , which is integrated into a vehicle component 44 of a vehicle 48, in this case into a side-view mirror 46, the housing of which is located at Figure 1B Partially shown in FIG. Figure 1C A schematic top view of a vehicle 48 is shown which includes such a projection unit 10 .

[0057] Due to the limited available space inside the side view mirror 46, the projection unit 10 can only be integrated obliquely relative to the longitudinal vehicle axis AL and / or the transverse vehicle axis AT. As a result, the image generated by the projection unit 10 and projected onto the projection surface 42 (in this case the ground below the side view mirror 46) is distorted and rotated relative to the longitudinal vehicle axis AL and / or the transverse vehicle axis AT, which is considered to be disadvantageous (see Figure 1C ).

[0058] Figure 2A and Figure 2C A first embodiment of a projection unit 491 according to the present disclosure is shown. Figure 1A and Figure 1B The descriptions are identical, so only the differences will be discussed below.

[0059] The projection unit 491 according to the first embodiment is equipped with a rear polarizer 50 which is part of the second lens unit 38 ( Figure 2C ). Following the travel path of light from the light source 12 to the projection surface 42 , the rear polarizer 50 is located after the polarizing beam splitter 30 and before the lens of the second lens unit 38 .

[0060] In the projection unit 491 according to the first embodiment of the present disclosure, the reflective microdisplay 32 (LCoS 36 in this case) is arranged to be rotated by a rotation angle α so that the column direction DC and the row direction DR are inclined relative to the first axis A1. The rotation angle α is embedded in the horizontal plane. Figure 2A and Figure 2C In the first embodiment shown in , the rotation angle α is selected such that the row direction DC extends parallel to the longitudinal vehicle axis AL.

[0061] As from Figure 2C It can be clearly seen that not only the LCoS 36 but also the reflector 28, the light source 12 and the first lens unit 14 are rotated about the first axis A1. The reflector 28 may be rotated at a different angle than the light source 12 and the first lens unit 14 (not explicitly shown).

[0062] The angle or angles at which reflector 28, light source 12, and first lens unit 14 are rotated are selected so that light is reflected by reflector 28 in a manner that fully illuminates LCoS 36. Furthermore, the angle or angles are selected so that a uniform light distribution of light impinging on LCoS 36 is achieved.

[0063] refer to Figure 2B And as mentioned previously, the prepolarizer 22 polarizes the light so that its waves extend within a first polarization plane 24 and a second polarization plane 26. Figure 2B In FIG. 2 , a first polarization plane 24 and a second polarization plane 26 are shown. Figure 2B Also shown is a reflective microdisplay 32. It can be seen that the first polarization plane 24 extends parallel to the row direction DR.

[0064] like Figure 2D As shown in FIG. 1 , the image generated by the projection unit 491 according to the present disclosure and projected onto the surface 42 is aligned with the longitudinal vehicle axis AL (see FIG. Figure 1C ) is aligned, has sharp contrast and uniform light distribution. Therefore, the image projected on the projection surface 42 is not only aligned in a desired manner, but also has high quality.

[0065] exist Figure 3 , a second embodiment of a projection unit 492 according to the present disclosure is shown with the aid of an isometric view. In this case, the reflective microdisplay 32 is implemented as a digital micromirror device 52 (DMD). The reflector 28 is formed by a conventional mirror 54, which is arranged so that light directed to the digital micromirror device 52 and reflected from the digital micromirror device does not impinge on the reflector 28. In the second embodiment, the projection unit 492 does not include a prepolarizer 22 and a rear polarizer 50. Apart from this, the basic functionality is largely comparable to that described with respect to the LCoS 36.

[0066] exist Figure 4 , a third embodiment of a projection unit 493 according to the present disclosure is shown with the aid of a perspective view. The design of the projection unit 493 according to the third embodiment is largely identical to the design of the projection unit 492 according to the second embodiment. However, the reflector 28 is formed by a prism 56 instead of a conventional mirror 54.

[0067] Reference numerals list

[0068] 10 Projection unit according to the prior art

[0069] 12 Light Source

[0070] 14. First lens unit

[0071] 16 Condenser lens

[0072] 18 Lens Array

[0073] 20 Fourier lens

[0074] 22 Prepolarizer

[0075] 24 First polarization plane

[0076] 26 Second polarization plane

[0077] 28 Reflector

[0078] 30 Polarization beam splitter

[0079] 32 Reflective Microdisplay

[0080] 34 Micro-reflective element

[0081] 35 Matrix

[0082] 36 Liquid Crystal on Silicon

[0083] 37 rows

[0084] 38 Second lens unit

[0085] 39 columns

[0086] 40 Lens

[0087] 42 Projection Surface

[0088] 44 Vehicle Parts

[0089] 46 Side view mirror

[0090] 48 Vehicles

[0091] 491-493 projection unit

[0092] 50 Rear polarizer

[0093] 52 Digital Micromirror Device

[0094] 54 Mirror

[0095] 56 Prism

[0096] A1 First axis

[0097] A2 Second axis

[0098] AL Longitudinal axis

[0099] AT Transverse axis

[0100] DC Column Direction

[0101] DR Line Direction

[0102] α Rotation angle

Claims

1. A projection unit (491, 492, 493) of a vehicle (48) or for a vehicle, comprising - a light source (12), - a reflective microdisplay (32) for reflecting light emitted by the light source (12), comprising o micro-reflective elements (34) arranged in a matrix (35), o the matrix (35) is defined by at least two rows (37) extending in a row direction (DR) and at least two columns (39) extending in a column direction (DC), o the row direction (DR) and the column direction (DC) extend perpendicular to each other, - a first lens unit (14) for collecting the light emitted by the light source (12) along a first axis (A1), a reflector (28) for directing the light collected by the first lens unit (14) along a second axis (A2) to the reflective microdisplay (32), - a second lens unit (38) for collecting light reflected by the reflective microdisplay (32) and for directing the collected light to a projection surface (42), wherein The reflective microdisplay (32) is arranged inside the projection unit (491, 492, 493), and the reflective microdisplay is rotated by a rotation angle (α) so that the row direction (DR) and / or the column direction (DC) are inclined relative to the first axis (A1).

2. The projection unit (491, 492, 493) according to claim 1, Features The reflector (28) is arranged inside the projection unit (491, 492, 493), and the reflector (28) rotates so that the light reflected by the reflector (28) is completely illuminated on the reflective micro display (32).

3. The projection unit (491, 492, 493) according to any one of claims 1 or 2, Features The light source (12) and / or the first lens unit (14) are arranged inside the projection unit (491, 492, 493), and the light source and / or the first lens unit are rotated so that the light irradiated onto the reflective microdisplay (32) has a uniform light distribution.

4. The projection unit (491, 492, 493) according to any one of the preceding claims, Features The reflective microdisplay (32) is implemented as a liquid crystal on silicon element (36).

5. The projection unit (491, 492, 493) according to claim 4, Features The first lens unit (14) comprises a pre-polarizer (22), and the reflector (28) is formed by a polarizing beam splitter (30).

6. The projection unit (491, 492, 493) according to claim 5, Features - the prepolarizer (22) polarizes light into a first polarization plane (24) and a second polarization plane (26), - the first polarization plane (24) and the second polarization plane (26) extend perpendicularly to each other, The prepolarizer (22) is arranged inside the projection unit (491, 492, 493), and the prepolarizer (22) is rotated so that the first polarization plane (24) extends parallel or perpendicular to the row direction (DR).

7. The projection unit (491, 492, 493) according to any one of claims 4 to 6, Features The second lens unit (38) includes a rear polarizer (50).

8. The projection unit (491, 492, 493) according to any one of claims 1 to 3, Features The reflective microdisplay (32) is implemented as a digital micromirror device (52).

9. The projection unit (491, 492, 493) according to claim 8, Features The reflector (28) is formed by a prism (56).

10. A vehicle component (44) comprising a projection unit (491, 492, 493) according to any of the preceding claims.

11. A vehicle (48) comprising a vehicle component according to claim 10 and / or a projection unit (491, 492, 493) according to claims 1 to 9.

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