Abstract:
A rear-view mirror ( 3 ) for a motor vehicle is provided with a reflector layer ( 40 ) which is used to reflect light which impinges on the rear-view mirror ( 3 ) from a first viewing direction, a display layer ( 36 ) which is arranged behind the reflector layer ( 40 ) in relation to the viewing direction ( 41 ) and which is used to emit light, a quarter wave plate ( 74 ) which is arranged between the display layer ( 36 ) and the reflector layer ( 40 ) and a reflecting linear-polarisation layer ( 73 ) which is arranged between the display layer and the quarter wave plate ( 74 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a continuation of co-pending International Application No. PCT/EP2005/009333 filed Aug. 30, 2005, which designates the United States, and claims priority to U.S. Provisional application number 60/622,249 filed Oct. 26, 2004. 
     
    
     TECHNICAL FIELD  
       [0002]     The invention concerns a rearview mirror for a motor vehicle.  
       BACKGROUND  
       [0003]     Such a rearview mirror may consist of a reflector layer for the reflection of light striking the mirror from a viewing direction and a display layer arranged behind the reflector layer relative to the viewing direction for the emission of light. Such a rearview mirror fulfills, in particular, a dual function. On the one hand, it serves as a rearview mirror in the conventional sense and on the other, as a display when the display layer emits light.  
         [0004]     U.S. Pat. No. 6,106,121 discloses a rearview mirror for a vehicle, wherein the rearview mirror includes an LCD display and two polarizing layers that are transparent when in an unpowered state.  
         [0005]     A mirror with a display is sold by Philips as MirrorTV. Details may be obtained, e.g., from the websites having the internet addresses www.ces2004.philips.com/downloads/press-releases/business-productivity/MirrorTV.pdf and www.pcworld.com/resource/printable/article/O,aid,1111OO,OO.asp  
         [0006]     EP 0 719 675 B1 discloses an interior mirror of a motor vehicle with a display device, said display device consisting of a mirror body, a rearview mirror provided in a front opening of the mirror body for reflecting an image behind a vehicle back to a viewing point of a driver and an information-displaying mirror provided in the mirror body for reflecting the visual information displayed by a light emitting display device back to the viewing point of the driver through the information display region, said rearview mirror displaying a semipermeable reflecting film applied to the entire rear surface of a glass substrate and a black-coated film applied to the rear surface of the semipermeable reflection film, part of the black-coated film being removed for presenting the information display and in which slits are provided in the light emission display device for guiding the information displayed by the light emitting display device in the direction of the information displaying mirror.  
         [0007]     EP 0 635 395 B1 discloses an information device in a motor vehicle that includes an electronic circuit that can be connected to the vehicle&#39;s power system and one or more sensors, an display device and optionally operating elements, where the sensor and the circuit are installed in the housing of an interior mirror of the vehicle, and where the circuit is connected by a cable guided through a hollow supporting arm of the interior mirror and connectable to the vehicle&#39;s power system, and in which the display device is integrated in the mirror glass of the interior mirror.  
         [0008]     DE 197 41 896 C2 discloses a device for displaying images of the environment around a motor vehicle in a field of vision of a driver situated in the interior of the motor vehicle, said device including at least one image screen, on which image information registered by sensors and processed electronically is displayed, at least one camera being present that is equipped with a sensor for registering image information and information on the spatial position of objects in the area surrounding the vehicle, and a control unit is provided for electronic processing of the image information registered by the sensors, the operating characteristics of the vehicle being fed to the control unit as input magnitudes, and said control unit switches back and forth between different modes of video display as a function of the operating characteristics.  
         [0009]     Other mirrors are known from U.S. Pat. No. 6,646,697 (incorporated by reference), U.S. Pat. No. 5, 864,432 (incorporated by reference), U.S. Pat. No. 6,700,692 (incorporated by reference), U.S. Pat. No. 6,648,477 (incorporated by reference), U.S. Pat. No. 6,646,806 (incorporated by reference), US 2003/0222982 (incorporated by reference), US 2004/0032675 (incorporated by reference), US 2004/0114384 (incorporated by reference), US 2004/0032676 (incorporated by reference), US 2003/0095047 (incorporated by reference), US 2003/0043480 (incorporated by reference), US 2002/0070872 (incorporated by reference), US 2001/0055143 (incorporated by reference) and US 2001/0013825 (incorporated by reference).  
       SUMMARY  
       [0010]     A rearview mirror can be improved with a mirror function and a display function. According to an embodiment, a rearview mirror for a motor vehicle, may comprise a reflector layer for reflecting light that strikes the rearview mirror from a viewing direction; a display layer for emitting light arranged behind the reflector layer relative to the viewing direction; a quarter waveplate arranged between the display layer and the reflector layer; and a reflecting linear polarization layer arranged between the display layer and the quarter waveplate. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     Other advantages and details may derived from the following description of examples of embodiment.  
         [0012]      FIG. 1  shows an example of embodiment of a motor vehicle;  
         [0013]      FIG. 2  shows an example of embodiment of a rearview mirror connected to a camera by an IT system;  
         [0014]      FIG. 3  shows an example of embodiment of a display in a rearview mirror;  
         [0015]      FIG. 4  shows another example of embodiment of a display in a rearview mirror;  
         [0016]      FIG. 5  shows another example of embodiment of a display in a rearview mirror;  
         [0017]      FIG. 6  shows another example of embodiment of a display in a rearview mirror;  
         [0018]      FIG. 7  shows another example of embodiment of a display in a rearview mirror;  
         [0019]      FIG. 8  shows another example of embodiment of a display in a rearview mirror;  
         [0020]      FIG. 9  shows an example of embodiment of a rearview mirror in an exploded view;  
         [0021]      FIG. 10  shows an example of embodiment of a mirror layer;  
         [0022]      FIG. 11  shows a reflectivity plotted against a wavelength of light;  
         [0023]      FIG. 12  shows another example of embodiment of a mirror layer;  
         [0024]      FIG. 13  shows another example of embodiment of a mirror layer;  
         [0025]      FIG. 14  shows another example of embodiment of a mirror layer;  
         [0026]      FIG. 15  shows a light permeability plotted against a wavelength of light; and  
         [0027]      FIG. 16  shows an example of embodiment of a part of a mirror layer for implementing a dimming function. 
     
    
     DETAILED DESCRIPTION  
       [0028]     A quarter waveplate may also be called an λ/4 plate. A quarter waveplate is used, e.g., as part of a circular polarizer. The quarter waveplate used according to an embodiment in this case in particular is not a deactivatable layer, such as that envisioned in U.S. Pat. No. 6,106,121. Suitable quarter waveplates can be obtained from the Polatechno Co., Ltd., Japan, www.polatechno.co.jp. Details on a quarter waveplate and circular polarizers can be obtained from the URL www.fas.harvard.edu˜scdiroff/lds/LightOptics/CircularPolaization/CircularPolarization.html  
         [0029]     A quarter waveplate in the sense of the invention is, in particular, a layer/film for rotating the polarization of light passing through the quarter waveplate by essentially  45  degrees.  
         [0030]     A reflecting linear polarization layer in the sense of the invention is, in particular, a layer or film that is essentially transparent for polarized light emitted from the display layer essentially in the through-passing direction and which essentially reflects the polarized light emitted by the display layer essentially orthogonally to the through-passing direction. The reflecting linear polarization layer may, for example, be designed as a so-called DBEF filter layer. Details regarding a DBEF filter layer may be obtained, e.g., from U.S. Pat. No. 6,747,618, (incorporated by reference), U.S. Pat. No. 6,753,999, (incorporated by reference), U.S. Pat. No. 6,481,851, (incorporated by reference) and U.S. Pat. No. 6,407,408 (incorporated by reference). Further details on a DBEF filter layers may be obtained, e.g., from the URLs:  
         [0000]     Produkts3.3m.com/catalog/us/en001/electronics_mfg/vikuiti/node_L9VF6WSX2Jbe/root_GST1T4S9TCgv/vroot_S6Q2FD9XOJge/gvel — 4Q2VBPLNL5gl/theme_us_vikuiti — 3 — 0/command_AbcPageHandler/output_print and the patents cited therein.  
         [0031]     The reflector layer is semitransparent especially in the sense that it is transparent for light emitted from the display layer but reflects light striking the rearview mirror from a viewing direction.  
         [0032]     According to an embodiment, the display layer includes a reflecting surface facing in the viewing direction.  
         [0033]     According to another embodiment, the rearview mirror also includes an anti-reflection layer arranged in front of the quarter waveplate relative to the viewing direction. Suitable anti-reflection layers are sold by Integrated Optical Services Corp., 291 Sinclair Frontage Rd., Milpitas, Calif. 95035, USA and Southwall Technologies Corp., 3975 East Bayshore Rd., Palo Alto, Calif. 94303, USA.  
         [0034]     According to another embodiment, the anti-reflection layer is connected to the quarter waveplate.  
         [0035]     LCDs, for example, may be considered for implementing the display layer. According to yet another embodiment, the display layer includes an OLED layer (polymer or especially small molecule) especially with a reflecting surface facing in the viewing direction.  
         [0036]     According to another embodiment, the reflector layer has a transparency of more than 99%, especially a transparency of more than 99.5%, for light striking the reflector layer against the viewing direction.  
         [0037]     According to another embodiment, the reflector layer includes one or more compounds of the group of TiO 2 , SiO 2 , and HfO 2 , especially a mixture of all of these compounds.  
         [0038]     According to another embodiment, at least 40%, especially at least 45%, of the light emittable by the display layer against the viewing direction emerges from the rearview mirror against the viewing direction. According to another embodiment, a brightness of more than 350 cd/m 2 , especially of more than 400 cd/m 2  can be achieved for light emerging from the rearview mirror against the viewing direction in the case of a light emitting display layer. That means, in a region of the rearview mirror in which the display layer delivers its full illuminating power, light with a brightness of more than 350 cd/m 2 , especially more than 400 cd/m 2  is emitted. A brightness of more than 500 cd/m 2  can also be achieved for light emerging from the rearview mirror against the viewing direction in the case of a light emitting display layer.  
         [0039]     According to another embodiment, a dimming layer for dimming the rearview mirror is arranged in front of the reflector layer relative to the viewing direction.  
         [0040]     According to another embodiment, the rearview mirror also includes an absorbing linear polarization layer arranged between the quarter waveplate and the reflecting linear polarization layer. An absorbing linear polarization layer in the sense of the invention is, in particular, a layer that is essentially transparent for polarized light emitted from the display layer essentially in the through-passing direction and which essentially absorbs the polarized light emitted by the display layer essentially orthogonally to the through-passing direction. The through-passing direction of the reflecting linear polarization layer and the through-passing direction of the absorbing linear polarization layer are essentially parallel in another embodiment.  
         [0041]     The above-noted problem is also solved by a rearview mirror for a motor vehicle, which rearview mirror consists of a reflector layer for the reflection of light striking the rearview mirror from a viewing direction, a display layer arranged behind the reflector layer relative to the viewing direction for the emission of light, and a quarter waveplate arranged between the display layer and the reflector layer, said reflector layer including one or more compounds of the group composed of TiO 2 , SiO 2 , and HfO 2 .  
         [0042]     According to an embodiment, the reflector layer contains a mixture of TiO 2 , SiO 2  and HfO 2 .  
         [0043]     According to another embodiment, the display layer includes a reflecting surface facing in the viewing direction.  
         [0044]     According to another embodiment, the rearview mirror also includes an anti-reflection layer arranged between the display layer and the reflector layer.  
         [0045]     According to another embodiment, the rearview mirror also includes an anti-reflection layer arranged between the quarter waveplate and the reflector layer.  
         [0046]     LCDs, for example, may be considered for implementing the display layer. According to yet another embodiment, the display layer includes an OLED layer (polymer or especially small molecule) especially with a reflecting surface facing in the viewing direction.  
         [0047]     According to another embodiment, the reflector layer has a transparency of more than 99%, especially a transparency of more than 99.5%, for light striking the reflector layer against the viewing direction.  
         [0048]     According to another embodiment, at least 40%, especially at least 45%, of the light emittable by the display layer against the viewing direction emerges from the rearview mirror against the viewing direction. According to another embodiment, a brightness of more than 350 cd/m 2 , especially of more than 400 cd/m 2  can be achieved for light emerging from the rearview mirror against the viewing direction in the case of a light emitting display layer. That means, in a region of the rearview mirror in which the display layer delivers its full illuminating power, light with a brightness of more than  350  cd/m 2 , especially more than 400 cd/m 2  is emitted. A brightness of more than 500 cd/m 2  can also be achieved for light emerging from the rearview mirror against the viewing direction in the case of a light emitting display layer.  
         [0049]     According to another embodiment, a dimming layer for dimming the rearview mirror is arranged in front of the reflector layer relative to the viewing direction.  
         [0050]     The above-noted problem is solved by a rearview mirror for a motor vehicle, which rearview mirror consists of a reflector layer for the reflection of light striking the rearview mirror from a viewing direction and a display layer (capable of being switched on and off) arranged behind the reflector layer for the emission of light in a direction against the viewing direction, where at least 40%, especially at least 45% of the light emittable by the display layer against the viewing direction emerges from the rearview mirror against the viewing direction. In this case, according to an embodiment, a quarter waveplate is arranged between the display layer and the reflector layer.  
         [0051]     According to another embodiment, a brightness of more than 350 cd/m 2 , especially of more than 400 cd/m 2 , can be achieved for light emerging from the rearview mirror against the viewing direction in the case of a light emitting display layer. That means, in a region of the rearview mirror in which the display layer delivers its full illuminating power, light with a brightness of more than 350 cd/m 2 , especially more than 400 cd/m 2  is emitted. A brightness of more than 500 cd/m 2  can also be achieved for light emerging from the rearview mirror against the viewing direction in the case of a light emitting display layer.  
         [0052]     According to another embodiment, the rearview mirror also includes an anti-reflection layer arranged behind the reflector layer relative to the viewing direction and/or arranged in front of the reflector layer relative to the viewing direction.  
         [0053]     LCDs, for example, may be considered for implementing the display layer. According to yet another embodiment, the display layer includes an OLED layer (polymer or especially small molecule).  
         [0054]     According to another embodiment, the reflector layer has a transparency of more than 99%, especially a transparency of more than 99.5%, for light striking the reflector layer against the viewing direction.  
         [0055]     According to another embodiment, the reflector layer includes one or more compounds of the group of TiO 2 , SiO 2 , and HfO 2 , especially a mixture of all of these compounds.  
         [0056]     According to another embodiment, a dimming layer for dimming the rearview mirror is arranged in front of the reflector layer relative to the viewing direction.  
         [0057]     The above-noted problem is solved by a rearview mirror for a motor vehicle, which rearview mirror consists of a reflector layer for the reflection of light striking the mirror from a viewing direction and a display layer (capable of being switched on and off) arranged behind the reflector layer for the emission of light, where in the case of a light-emitting display layer a brightness of more than 350 cd/m 2 , especially more than 400 cd/m 2 , can be achieved for the light emerging from the rearview mirror against the viewing direction. That means, in a region of the rearview mirror in which the display layer delivers its full illuminating power, light with a brightness of more than 350 cd/m 2 , especially more than 400 cd/m 2 , is emitted. In this case, according to another embodiment, a quarter waveplate is arranged between the display layer and the reflector layer. A brightness of more than 500 cd/m 2  can also be achieved for light emerging from the rearview mirror against the viewing direction in the case of a light emitting display layer.  
         [0058]     LCDs may be considered, e.g., for implementing the display layer. According to yet another embodiment, the display layer includes an OLED layer (polymer or especially small molecule).  
         [0059]     According to another embodiment, the reflector layer has a transparency of more than 99%, especially a transparency of more than 99.5%, for light striking the reflector layer against the viewing direction.  
         [0060]     According to another embodiment, the reflector layer includes one or more compounds of the group of TiO 2 , SiO 2 , and HfO 2 , especially a mixture of all of these compounds.  
         [0061]     According to another embodiment, a dimming layer for dimming the rearview mirror is arranged in front of the reflector layer relative to the viewing direction.  
         [0062]     The above noted problem is solved by a rearview mirror for a motor vehicle, which rearview mirror consists of a reflector layer for the reflection of light striking the mirror from a viewing direction and a display layer (capable of being switched on and off) arranged behind the reflector layer relative to the viewing direction for the emission of light, a quarter waveplate arranged between the display layer and the reflector layer, an absorbing linear polarization layer arranged between the display layer and the quarter waveplate, and an absorbing linear polarization layer arranged between the display layer and the reflecting linear and reflecting linear polarization layer. The through-passing direction of the reflecting linear polarization layer and the through-passing direction of the absorbing linear polarization layer are essentially parallel according to another embodiment.  
         [0063]     According to another embodiment, the display layer includes a reflecting surface facing in the viewing direction.  
         [0064]     According to another embodiment, the rearview mirror also includes an anti-reflection layer arranged in front of the quarter waveplate relative to the viewing direction. According to another embodiment, the anti-reflection layer is connected to the quarter waveplate.  
         [0065]     LCDs, for example, may be considered for implementing the display layer.  
         [0066]     According to yet another embodiment, the display layer includes an OLED layer (polymer or especially small molecule) especially with a reflecting surface facing in the viewing direction.  
         [0067]     According to another embodiment, the reflector layer has a transparency of more than 99%, especially a transparency of more than 99.5%, for light striking the reflector layer against the viewing direction.  
         [0068]     According to another embodiment, the reflector layer includes one or more compounds of the group of TiO 2 , SiO 2 , and HfO 2 , especially a mixture of all of these compounds.  
         [0069]     According to another embodiment, at least 40%, especially at least 45%, of the light emittable by the display layer against the viewing direction emerges from the rearview mirror against the viewing direction. According to another embodiment, a brightness of more than 350 cd/m 2  especially of more than 400 cd/m 2 , can be achieved for light emerging from the rearview mirror against the viewing direction in the case of a light emitting display layer. That means, in a region of the rearview mirror in which the display layer delivers its full illuminating power, light with a brightness of more than 350 cd/m 2 , especially more than 400 cd/m 2 , is emitted. A brightness of more than 500 cd/m 2  can also be achieved for light emerging from the rearview mirror against the viewing direction in the case of a light emitting display layer.  
         [0070]     According to another embodiment, a dimming layer for dimming the rearview mirror is arranged in front of the reflector layer relative to the viewing direction.  
         [0071]     According to another embodiment, the quarter waveplate is a passive layer. According to another embodiment, the reflecting linear polarization layer is a passive layer. According to another embodiment, the absorbing linear polarization layer is a passive layer.  
         [0072]     The above-noted problem is also solved by a rearview mirror for a motor vehicle, which rearview mirror consists of a reflector layer for the reflection of light striking the rearview mirror from a viewing direction, a OLED layer arranged behind the reflector layer relative to the viewing direction for the emission of light, a first anti-reflection layer arranged between the OLED layer and the reflector layer, and a second anti-reflection layer arranged in front of the reflector layer relative to the viewing direction.  
         [0073]     According to another embodiment, a dimming layer for dimming the rearview mirror is arranged in front of the reflector layer relative to the viewing direction.  
         [0074]     The above-noted problem is solved by a rearview mirror for a motor vehicle, which rearview mirror consists of a reflector layer for the reflection of light striking the rearview mirror from a viewing direction, and a display layer (capable of being switched on and off) arranged behind the reflector layer relative to the viewing direction for the emission of light, where the reflector layer contains one or more compounds from the group consisting of TiO 2 , SiO 2  und HfO 2 , especially a mixture of all these compounds.  
         [0075]     The above-noted problem is also solved by a motor vehicle with one of the above-noted rearview mirrors. Such a motor vehicle in one variant includes a camera connected by an IT system to the display layer for taking a picture of the area surrounding the vehicle, in which case it is envisioned in particular that the image recorded by the camera is optionally displayable in the rearview mirror by means of the display layer.  
         [0076]     Motor vehicle in the sense of the invention refers in particular to a ground vehicle used individually in road traffic. Motor vehicles in the sense of the invention are not limited specifically to ground vehicles with internal combustion engines.  
         [0077]      FIG. 1  shows an example of embodiment of a motor vehicle  1 . The motor vehicle  1  contains a camera  2  that is IT-linked by means of a video adapter  5  shown in  FIG. 2  to a rearview mirror  3  to take a picture of the surroundings of the motor vehicle  1 . The camera  2  in this case is arranged in the example of embodiment shown essentially in the center of the trunk of the vehicle  1  so that a region behind the vehicle  1 , and with it, e.g., as shown in  FIG. 2 , another vehicle behind the vehicle  1  is photographed by the camera  2  and can be displayed by the rearview mirror  3  which includes a display function as elaborated with reference to the following figures.  
         [0078]     The rearview mirror  3  has a dual function. On the one hand, the rearview mirror  3  may be used as a rearview mirror in the conventional sense, and on the other, as a display, in which case optionally or coupled to certain operating states of the vehicle  1  it can be switched between the function as rearview mirror in the conventional sense and the function as a display. Thus, for example, it may be envisioned that the rearview mirror  3  will show an image taken by the camera  2  when the vehicle  1  is moving in reverse and that the rearview mirror  3  is a rearview mirror in the conventional sense when the vehicle  1  is moving forward.  
         [0079]     Alternatively, or additionally, operating means such as switches or a voice command may be provided for optional switching between the two above-noted states of the rearview mirror  3 .  
         [0080]     Alternatively or in addition to the representation shown in  FIG. 2  of a picture taken by the camera  2 , also, as shown in  FIG. 3 ,  FIG. 4 ,  FIG. 5 ,  FIG. 6 ,  FIG. 7  and  FIG. 8 , other pictures may be displayed by means of the rearview mirror  3 . Thus  FIG. 3  shows an example of embodiment of the display of a direction notice  11  generated by a navigation system in the rearview mirror  3 .  FIG. 4  shows an example of embodiment of the display of a road map  12  generated by a navigation system in the rearview mirror  3 , and  FIG. 5  shows an example of embodiment of a display of a geographic direction notice  14  in the rearview mirror  3  generated by a compass.  
         [0081]     With the rearview mirror  3  a display, as is shown in  FIG. 2  and  FIG. 4 , can extend over a significant part of the rearview mirror  3 . However, it may also be provided that only a part of a rearview mirror can be used as a display while another part of such a rearview mirror may also be used in a display state as a mirror.  FIG. 6 ,  FIG. 7  and  FIG. 8  show such a rearview mirror  20 , where  FIG. 6  shows an example of embodiment of the display of a direction notice  21  generated by a navigation system in the rearview mirror  20 ,  FIG. 7  an example of embodiment of a display of a roadmap  22  generated by a navigation system in the rearview mirror  20 , and  FIG. 8  an example of embodiment of a display of a geographic direction notice  24  generated by a compass in the rearview mirror  20 . In the case of the rearview mirror  20  only the right third of the rearview mirror  20  can be used as a display, while the left two thirds of the rearview mirror  20  may also be used as a mirror even in the display mode.  
         [0082]     Alternatively or additionally, other information concerning the vehicle  1  such as the distance to an obstacle, the speed of the vehicle  1 , etc., or the time can be displayed by the rearview mirror  3  and the rearview mirror  20 , respectively.  
         [0083]      FIG. 9  shows the rearview mirror  20  in an exploded view. In this case the reference number  30  denotes a rearview mirror housing. Reference number  31  denotes a circuit board housing for holding a circuit board  33  with a control system for a display layer  36  configured as an OLED. Reference number  32  denotes a cable for connecting the circuit board  33 , and reference number  35  a housing for holding the display layer  36 . The display layer  36  is arranged in a recess  38  of a template  37  which in turn is arranged behind a mirror layer  40  relative to a viewing direction  41 . Reference number  39  denotes a frame that can be joined together with the mirror housing  30 . Reference number  34  denotes a circuit board for implementing other functions of the rearview mirror  20  such as implementing a dimmer function. The circuit boards  33  and  34  may also be replaced by a single circuit board. The rearview mirror  3  is configurable in a manner corresponding to the example of the rearview mirror  20  shown in  FIG. 9 . However, in this case a larger recess and a correspondingly larger display layer are to be provided. The template  37  may also be omitted.  
         [0084]      FIG. 10  shows a cross section of an example of embodiment of a mirror layer  50  for use as a mirror layer  40  according to  FIG. 9  with an OLED layer  51  corresponding to the display layer  36  arranged on a side of the mirror layer  50  facing away from the viewing direction  41 . The mirror layer  50  includes a glass layer  54  and a semitransparent reflector layer  53  arranged behind the glass layer  54  relative to the viewing direction  41 . The semitransparent reflector layer  53  is transparent for light emitted by the OLED layer  51  but reflects light striking the rearview mirror  20  from the viewing direction  41 . In a preferred variant, the semitransparent reflector layer  53  includes one or more compounds of the group TiO 2 , SiO 2 , and HfO 2 , especially a mixture of all of these compounds. Such a semitransparent reflector layer  53  has a transparency of more than 99%, especially a transparency of more than 99.5%, for light striking the semitransparent reflector layer  53  against the viewing direction  41 .  
         [0085]     Between the OLED layer  51  and the semitransparent reflector layer  53  and relative to the viewing direction  41  in front of the glass layer  54 , one anti-reflection layer  52  and  55  is arranged each. Suitable anti-reflection layers are sold by Integrated Optical Services Corp., 291 Sinclair Frontage Rd., Milpitas, Calif. 95035, USA and Southwall Technologies Corp., 3975 East Bayshore Rd., Palo Alto, Calif. 94303, USA. Details on the anti-reflection layers are also disclosed at the URL www.cvilaser.com/static/tech_arcoatings.asp?PrintFriendly&gt;&gt;TRUE.  FIG. 11  shows the reflectivity  59  of a suitable anti-reflection layer plotted against the wavelength of light. Reference number  58  in this case denotes the reflectivity without an anti-reflection layer.  
         [0086]      FIG. 12  shows a cross section of an example of embodiment of a mirror layer  60  that is improved relative to the example of embodiment of  FIG. 10  for use as a mirror layer  40  as in  FIG. 9  with a display layer  61  configured in particular as an OLED layer, corresponding to display layer  36  on a side of the mirror layer  60  facing away from the viewing direction  41 . The mirror layer  60  contains a glass layer  66  and a semitransparent reflector layer  65  arranged behind the glass layer  66  relative to the viewing direction  41 , corresponding to the semitransparent reflector layer  53 . One anti-reflection layer  64  and  67  each corresponding to the anti-reflection layer  52  and  55  is arranged behind the semitransparent reflector layer  65  relative to viewing direction  41  and in front of the glass layer  66  relative to viewing direction  41 .  
         [0087]     The mirror layer  60  also contains a quarter waveplate  63  arranged behind the anti-reflection layer  64  relative to viewing direction  41  and an absorbing linear polarization layer  62  arranged between the display layer  61  and the quarter waveplate  63 . The absorbing linear polarization layer  62  is essentially transparent for polarized light emitted essentially in a through-going direction of the absorbing linear polarization layer  62  and absorbs the polarized light emitted by the display layer  61  essentially orthogonally to the through-passing direction of the absorbing linear polarization layer  62 .  
         [0088]      FIG. 13  shows a cross section of an example of embodiment of a mirror layer  70  that is further improved relative to the example of embodiment of  FIG. 12  for use as a mirror layer  40  as in  FIG. 9  with an OLED layer  71 , corresponding to display layer  36 , on a side of the mirror layer  70  facing away from the viewing direction  41 , with a reflecting surface  72 . Details on suitable OLED layers with a reflecting surface may be obtained from U.S. Pat. No. 6,747,618 (incorporated by reference), U.S. Pat. No. 6,753,999 (incorporated by reference), U.S. Pat. No. 6,481,851 (incorporated by reference), U.S. Pat. No. 6,407,408 (incorporated by reference) and US 2004/0069985 A1 (incorporated by reference).  
         [0089]     The mirror layer  70  contains a glass layer  77  and a semitransparent reflector layer  76  arranged, relative to the viewing direction  41 , behind the glass layer  77 , corresponding to the semitransparent reflector layer  53 . Relative to the viewing direction  41 , optionally an anti-reflection layer  75 , corresponding to anti-reflection layer  52  and  55 , is arranged behind the semitransparent reflector layer  76 . Relative to the viewing direction  41 , an anti-reflection layer  78 , corresponding to anti-reflection layer  52  and  55 , is arranged in front of the glass layer  77 .  
         [0090]     The mirror layer  70  also contains a quarter waveplate  74  arranged relative to viewing direction  41  behind the anti-reflection layer  75  and behind the semitransparent reflector layer  76  and a reflecting linear polarization layer  73  especially designed as a so-called DBEF filter layer, arranged between the display layer  71  and the quarter waveplate  74 . The reflecting linear polarization layer  73  is essentially transparent for polarized light emitted by the display layer  71  essentially in a through-going direction of the reflecting linear polarization layer  73  and reflects the polarized light emitted by the display layer  71  essentially orthogonally to the through-passing direction of the reflecting linear polarization layer  73 .  
         [0091]      FIG. 14  shows a cross section of an especially suitable example of embodiment of a mirror layer  80  for use as a mirror layer  40  according to  FIG. 9  with an OLED layer  81  with a reflecting surface  82  corresponding to the display layer  36 , arranged on a side of the mirror layer  80  facing away from the viewing direction  41 . The mirror layer  80  contains a glass layer  88  and a semitransparent reflector layer  87  arranged behind the glass layer  88 , relative to the viewing direction  41 , corresponding to the semitransparent reflector layer  53 . Behind the semitransparent reflector layer  87  relative to the viewing direction  41  optionally an anti-reflection layer  86 , corresponding to the anti-reflection layer  52  and  55 , is arranged. Relative to the viewing direction  41 , an anti-reflection layer  89 , corresponding to anti-reflection layer  52  and  55 , is arranged in front of the glass layer  88 .  
         [0092]     The mirror layer  80  contains a quarter waveplate  85  arranged, relative to viewing direction  41 , behind the anti-reflection layer  86  and behind the semitransparent reflector layer  87  and an absorbing linear polarization layer  84  arranged between the display layer  81  and the quarter waveplate  85 . Between the absorbing linear polarization layer  84 , a reflecting linear polarization layer  83 , designed especially as a DBEF filter layer, is arranged. The reflecting linear polarization layer  83  is essentially transparent for polarized light emitted by the display layer  81  essentially in a through-going direction of the reflecting linear polarization layer  83  and reflects the polarized light emitted by the display layer  81  essentially orthogonally to the through-passing direction of the reflecting linear polarization layer  83 . The absorbing linear polarization layer  84  is essentially transparent for polarized light emitted by the display layer  81  essentially in a through-going direction of the absorbing linear polarization layer  84  and absorbs the polarized light emitted by the display layer  81  essentially orthogonally to the through-passing direction of the absorbing linear polarization layer  84 . The through-passing direction of the absorbing linear polarization layer  84  is essentially parallel to the through-passing direction of the reflecting linear polarization layer  83 .  
         [0093]     The arrangement of quarter waveplate  85 , absorbing linear polarization layer  84  and reflecting linear polarization layer  83  can be replaced by a so-called DRD filter.  
         [0094]     A rearview mirror  3  or  20  configured according to the arrangement in  FIG. 14  permits the display of especially high-contrast and sharp and simultaneously bright images. Therefore, in the case of the light-emitting display layer  81 , a brightness of more than 350 cd/m 2 , especially of more than 400 cd/m 2 , can be achieved for light emerging from the rearview mirror  3  or  20  against the viewing direction  41 . That means, in a region of the rearview mirror  3  or  20  in which the display layer  81  delivers its full illuminating power, light with a brightness of more than 350 cd/m 2 , especially more than 400 cd/m 2 , is emitted. With some OLEDs brightness of even more than 500 cd/m 2  is achievable.  FIG. 15  shows the proportion of the light emittable by the display layer  81  against the viewing direction  41  that emerges against the viewing direction  41  from the rearview mirror  3  or  20 , implemented according to  FIG. 14 , plotted against wavelength. In this case  FIG. 15  shows that for every relevant wavelength in the visible region at least 45% of the light emitted by the display layer  81  against the viewing direction  41  emerges against the viewing direction  41  from the rearview mirror  3  or  20  implemented according to  FIG. 14 .  
         [0095]     It is envisioned in particular that the quarter waveplates  63 ,  74 ,  85 , the absorbing linear polarization layers  62 ,  84 , and the reflecting linear polarization layers  73 ,  83  are especially passive layers.  
         [0096]      FIG. 16  shows an example of embodiment of a part of a mirror layer for implementation of a dimming function, wherein this part replaces the arrangement of semitransparent reflector layer  53  and glass layer  54  in  FIG. 10 , the arrangement of semitransparent reflector layer  65  and glass layer  66  in  FIG. 12 , the arrangement of semitransparent reflector layer  76  and glass layer  77  in  FIG. 13  and the arrangement of semitransparent reflector layer  87  and glass layer  88  in  FIG. 10  for implementation of a dimming function. The part of a mirror layer shown in  FIG. 16  includes a glass layer  91  and a glass layer  96 , where a semitransparent reflector layer  92  is arranged between the glass layer  91  and glass layer  96  relative to the viewing direction  41  in front of glass layer  91 . Between glass layer  96  and the semitransparent reflector layer  92  a dimming layer is arranged, which contains an electrochromatic layer  94  arranged between two ITO electrodes  93  and  95 .  
         [0097]     Optionally, an anti-reflection layer corresponding to anti-reflection layer  52  and  55  is arranged between the semitransparent reflector layer  92  and the ITO electrode  93  and/or between the ITO electrode  95  and the glass layer  96 .  
         [0098]     The elements and layers in the figures were drawn with consideration of simplicity and clarity and are not necessarily true to scale. Thus, for example, the orders of magnitude of some elements or layers are clearly exaggerated relative to other elements or layers in order to improve the understanding of the examples of embodiment of the present invention.  
       List of Reference Numbers  
       [0000]    
       
           1  Motor vehicle  
           2  Camera  
           3 ,  20  Rearview mirror  
           5  Video adapters  
           11 ,  21  Direction notice  
           12 ,  22  Roadmap  
           14 ,  24  Geographic direction notice  
           30  Rearview mirror housing  
           31  Circuit board housing  
           32  Cable  
           33 ,  34  Circuit board  
           35  Housing  
           36 ,  61  Display layer  
           37  Template  
           38  Recess  
           39  Frame  
           40 ,  50 ,  60 ,  70 ,  80  Mirror layer  
           41  Viewing direction  
           51 ,  71 ,  81  OLED layer  
           52 ,  55 ,  64 ,  67 ,  
           75 ,  78 ,  86 ,  89  Anti-reflection layer  
           53 ,  65 ,  76 ,  87 ,  92  Semitransparent reflector layer  
           54 ,  66 ,  77 ,  88   91 ,  96  Glass layer  
           58 ,  59  Reflectivity  
           62 ,  84  Absorbing linear polarization layer  
           63 ,  74 ,  85  Quarter waveplate  
           72 ,  82  Reflecting surface  
           73 ,  83  Reflecting linear polarization layer  
           93 ,  95  ITO electrode  
           94  Electrochromatic layer