Patent Publication Number: US-11642961-B2

Title: Combined head up display (HUD) and camera system

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. application Ser. No. 15/668,903 filed on Aug. 4, 2017, which claims benefit of U.S. Provisional Application No. 62/370,991 filed on Aug. 4, 2016, the disclosures of which are hereby incorporated by reference in their entireties for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The disclosure relates to combining a head up display (HUD) and a driver monitoring camera in a motor vehicle. 
     BACKGROUND OF THE INVENTION 
     A head up display emits light that reflects from the front windshield to be seen by the driver. The light appears to come from a virtual image in front of the driver and in front of the windshield. 
     Conventional head up displays create the virtual image by first using a display to create an image. Next, the light from the image is reflected from one or more mirrors, and then the light from the mirrors is reflected from the windshield. The mirrors are designed and positioned relative to the display so that the light seen by the driver, which is reflected from the windshield, appears to come from a virtual image that is outside of the vehicle. The mirrors and display are typically contained in a package that occupies a volume beneath the top surface of the dashboard. 
     Driver monitoring cameras are currently difficult to place in the vehicle. The driver monitoring cameras need to have a clear, unobstructed front angle view of the driver, but the cameras cannot be allowed to obstruct the driver&#39;s view of the road. Today&#39;s systems are located on the steering column or are mounted on top of the dash. Both locations are non-optimal since their view can be obstructed, and the camera itself can be distracting to the driver. 
     SUMMARY 
     The present invention may provide an arrangement in which a driver monitoring camera is combined in the same module housing with the HUD light field emitter. The camera and HUD light field emitter may share the same optics, such as a same mirror. Combining the camera with the HUD enables the same optics that deliver the visual HUD display to the driver to also be used to deliver the image of the driver&#39;s face to the camera. The driver monitoring camera may be combined with any part of the HUD optics. For example, any of the reflecting mirrors may include a small hole through which the camera can see the image of the driver&#39;s face. The camera may also be placed alongside the HUD package itself and receive the image of the driver&#39;s face after the image has been reflected off of the windshield alone or windshield plus any number of mirrors or lenses. Additionally, the image may be reflected off coated lenses that reflect IR light but transmit visible light. 
     In one embodiment, the invention comprises an optical arrangement for a motor vehicle, including a head up display light field emitter that emits a light field. At least one mirror is positioned to reflect the light field such that the light field is again reflected by a windshield of the vehicle, and such that the light field is visible to a driver of the vehicle as a virtual image. A driver monitoring camera is positioned to capture an image of a face of the driver that is reflected off of the windshield directly or including one or more mirrors. Alternatively, it is possible for the driver monitoring camera to catch the reflection directly off the windshield without the use of any mirrors. 
     In another embodiment, the invention comprises an optical method for a motor vehicle, including emitting a light field based on image data. The light field is reflected with at least one mirror such that the light field further reflects off of a windshield of the motor vehicle and is visible to a driver of the vehicle as a virtual image. A driver monitoring camera is used to capture an image of a face of the driver that is reflected off of the windshield and the one or more mirrors. 
     In yet another embodiment, the invention comprises an optical arrangement for a motor vehicle, including a head up display light field emitter that emits a light field. At least one mirror is positioned to reflect the light field such that the light field is again reflected by a windshield of the vehicle, and such that the light field is visible to a driver of the vehicle as a virtual image. At least one mirror has a transparent section for IR light. A driver monitoring camera is positioned to capture an image of a face of the driver through the transparent section of the at least one mirror. 
     In still another embodiment, the invention comprises an optical arrangement for a motor vehicle, including a head up display light field emitter that emits a light field. At least one optical element is positioned to reflect the light field such that the light field is again reflected by a windshield of the vehicle, and such that the light field is visible to a driver of the vehicle as a virtual image. The at least one optical element includes at least one mirror and/or at least one lens. The at least one optical element is reflective to visible light and transparent for IR light. A driver monitoring camera is positioned to capture an IR image of a face of the driver reflected off of the windshield and passing through the at least one optical element. 
     An advantage of the present invention is that it solves the problem of where to place a driver monitoring camera by combining it with the Heads Up Display (HUD). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of the present invention will be had upon reference to the following description in conjunction with the accompanying drawings. 
         FIG.  1    is a schematic view of one example embodiment of a combined HUD and driver monitoring camera arrangement of the present invention. 
         FIG.  2    is a flow chart of one embodiment of an optical method of the present invention for a motor vehicle. 
         FIG.  3    is a schematic view of another example embodiment of a combined HUD and driver monitoring camera arrangement of the present invention. 
         FIG.  4    is a schematic view of yet another example embodiment of a combined HUD and driver monitoring camera arrangement of the present invention. 
         FIG.  5    is a schematic view of still another example embodiment of a combined HUD and driver monitoring camera arrangement of the present invention. 
         FIG.  6    is a schematic view of a further example embodiment of a combined HUD and driver monitoring camera arrangement of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG.  1    illustrates one example embodiment of a combined HUD and driver monitoring camera arrangement  10  of the present invention, including a HUD display screen and driver monitoring camera module  12 , a fold mirror  14 , an aspheric mirror  16 , and a windshield  18 . Module  12  includes a HUD display screen  20  and a driver monitoring camera  22 . HUD display screen  20  and driver monitoring camera  22  may be disposed within a common housing, or may be disposed adjacent to each other. HUD display screen  20  and driver monitoring camera  22  may be illustrated as being physically separated by a substantial distance in  FIG.  1    for ease of illustration, but may be close enough together to share optics including mirrors  14 ,  16  and windshield  18 . That is, a light field from screen  20  may be reflected by mirrors  14 ,  16  and windshield  18  and be seen by a driver  24 . Similarly, an image of a face of driver  24  may be reflected by windshield  18 , mirrors  16 ,  14  and be captured by camera  22 . 
     During use, HUD display screen  20  emits a light field that is reflected sequentially off of mirror  14 , mirror  16 , and windshield  18  such that the light field is visible to driver  24  as a virtual image  26  that appears to be disposed over the front bumper of the vehicle. Camera  22  captures an image of the face of driver  24  that is reflected sequentially off of windshield  18 , mirror  16 , and mirror  14 . 
     In another embodiment, instead of capturing the image of the driver&#39;s face as a reflection off of windshield  18 , mirror  16 , and mirror  14 , camera  22  captures the image of the driver&#39;s face directly along imaginary line  28  and through a throughhole  30  in mirror  14 . Instead of throughhole  30 , mirror  14  may have a transparent section through which camera  22  may see the driver&#39;s face. Imaginary line  28  may extend through an air gap in steering wheel  32 , or may be disposed outside of steering wheel  32 . It is also possible for imaginary line  28  to be offset from mirror  14  such that no throughhole or transparent section in mirror  14  is needed. 
       FIG.  2    is a flow chart of one embodiment of an optical method  200  of the present invention for a motor vehicle. In a first step  202 , a light field is emitted based on image data. For example, HUD display screen  20  may emit a light field based on image data from an electronic processor (not shown). 
     In a next step  204 , the light field is reflected with at least one mirror such that the light field further reflects off of a windshield of the motor vehicle and is visible to a driver of the vehicle as a virtual image. For example, the light field emitted by HUD display screen  20  may be reflected by mirrors  14 ,  16  such that the light field further reflects off of windshield  18  of the motor vehicle and is visible to driver  24  of the vehicle as a virtual image  26 . 
     In a final step  206 , a driver monitoring camera is used to capture an image of a face of the driver that is reflected off of the windshield and the at least one mirror. For example, driver monitoring camera  22  may be used to capture an image of a face of driver  24  that is reflected off of windshield  18  and mirrors  14 ,  16 . 
       FIGS.  3 - 7    illustrate embodiments of an inventive combined HUD and driver monitoring camera arrangement including use of a coating that is either reflective for infrared (IR) light and transparent for visible light, or vice versa (e.g., transparent for IR and reflective for visible). This makes it possible for a windshield or optical element to function as a lens in one spectrum while functioning as a mirror in the other spectrum. The windshield or optical element functioning as both a lens and a mirror enables the camera to get a clear image of the face while not interfering with the HUD image presented to the driver. 
     Arrangement  300  includes a windshield  318  and a camera  322 , and may not include a HUD. Windshield  318  includes a coating that is reflective of IR energy and at least partially transparent to visible light. Thus, driver  324  may see the road through windshield  318 , as indicated at  334 , and windshield  318  may reflect IR light to camera  322 , as indicated at  336 , such that camera  322  may capture images of driver  324 . 
     Arrangement  400  includes a windshield  418 , a camera  422 , and a combiner (lens)  438 , and may not include a HUD. Combiner  438  includes a coating that is reflective of IR energy and at least partially transparent to visible light. Thus, driver  424  may see the road through windshield  418  and combiner  438 , as indicated at  434 , and combiner  438  may reflect IR light to camera  422 , as indicated at  436 , such that camera  422  may capture images of driver  424 . 
     Arrangement  500  includes a windshield  518 , a camera  522 , at least one optical element  538  which may include at least one lens and/or at least one mirror, and a HUD display screen  520 . Windshield  518  includes a coating that is reflective of IR energy and at least partially transparent to visible light. Optical element  538  is reflective of IR energy and transparent to visible light, perhaps by virtue of including a coating with these properties. Thus, driver  524  may see the road through windshield  518 , as indicated at  534 , and optical element  538  may reflect IR light to camera  522 , as indicated at  536 , such that camera  522  may capture images of driver  524 . Further, optical element  538  does not interfere with a light field that is emitted by HUD display screen  520  and reflected off windshield  518  to driver  524 . 
     Arrangement  600  includes a windshield  618 , a camera  622 , at least one optical element  638  which may include at least one lens and/or at least one mirror, and a HUD display screen  620 . Windshield  618  includes a coating that is reflective of IR energy and at least partially transparent to visible light. Optical element  638  is transparent to IR energy and reflective of visible light, perhaps by virtue of including a coating with these properties. Thus, driver  624  may see the road through windshield  618 , as indicated at  634 , and optical element  638  may pass IR light to camera  622 , as indicated at  636 , such that camera  622  may capture images of driver  624 . Further, optical element  638  reflects a light field that is emitted by HUD display screen  620  such that the light field is reflected off windshield  618  to driver  624 . The foregoing description may refer to “motor vehicle”, “automobile”, “automotive”, or similar expressions. It is to be understood that these terms are not intended to limit the invention to any particular type of transportation vehicle. Rather, the invention may be applied to any type of transportation vehicle whether traveling by air, water, or ground, such as airplanes, boats, etc. 
     The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom for modifications can be made by those skilled in the art upon reading this disclosure and may be made without departing from the spirit of the invention.