Patent Publication Number: US-2009225434-A1

Title: Vehicle rear view apparatus utilizing heads up display and rear looking sensors

Description:
BACKGROUND OF THE INVENTION 
     The present apparatus relates, in general, to vehicle rear view systems and, also, to vehicular heads up displays. 
     Currently, rear view mirrors are mandated technology in vehicles to provide rear looking information to the vehicle driver. The rear view mirrors are located in the upper center of the vehicle windshield and with proper adjustment, the rear view mirrors provide an adequate view of the landscape or area behind the vehicle. However, due to the location of the rear view mirror, it can cause minor to severe frontal viewing obstructions. 
     The viewing performance of the rear view mirrors depends on several factors, including driver size, mirror location, rear vehicle contour and rear window size. In the case of commercial vehicles, there are many instances where the rear window is obstructed during practical use such that the driver has to depend on wide side view mirrors. 
     However, due to the location of the rear view mirror, it can cause minor to severe frontal viewing obstructions. 
     Since mirrors were first introduced in automobiles, technology has advanced to where there are other ways of providing information regarding the area behind the vehicle. Such alternate methods include a visual view or image of the area behind the vehicle as provided by the inside rear view mirror, enhanced viewer image of the exterior of the vehicle through a camera or imaging device, the distance to an object which can be either parametric data or relative distance indicated by a graphical interface, the projected path of the vehicle as it travels in reverse, highlighting of the most critical object of interest (i.e., the closest object behind the vehicle), and information regarding speed based time to collision with an object behind the vehicle. Most of such methods effectively do not obstruct the forward view of the driver. 
     However, all such rear viewing systems distract the driver to some extent from a forward looking position. Even an alarm based rear view system which merely generates an audible tone of increasing frequency as the vehicle approaches an object when traveling in reverse, distracts the driver from looking forward and frequently cause the driver to turn his head to view the rear of the vehicle or to look in the rear view mirror. Camera systems and graphical interfaces are typically mounted in the instrument panel of the vehicle, which again requires the driver to turn his eyes toward the instrument panel from a forward view through the windshield. 
     Thus, it would be desirable to provide a vehicle rear view system which overcomes the aforementioned problems by providing accurate rear viewing information to a vehicle driver all in the safe driving line of sight of the driver through the windshield. 
     SUMMARY OF THE INVENTION 
     A vehicle rear view apparatus includes a heads up display capable of projecting an image onto a windshield of a vehicle, a rear view sensor adapted to be mounted on the vehicle for providing rear view data representative of the environment to the rear of the vehicle; and a connection between the rear view sensor and the heads up display to provide the output of the rear view sensor to the heads up display for projection of the rear view data in the front line of sight of the vehicle driver. 
     The rear view sensor may include at least one of a video camera, an object detector, a distance to object detector, an ultrasonic object detector, a device for projecting the path of the vehicle when moving in reverse and a speed base time to collision with an object behind the vehicle sensor. 
     The connection includes a hardwired connection between the rear view sensor and the heads up display, and a wireless transmitter and receiver coupled to the rear view sensor and the heads up display to wirelessly communicate the output of the rear view sensor to the heads up display. 
     A method of communicating rear view data representative of the environment rearward of a vehicle to a location viewable by a driver of the vehicle comprises the steps of communicating rear view data between at least one rear view sensor on the vehicle and a heads up display mounted in the vehicle, and projecting a visual image by the heads up display representative of the rear view data in a forward looking line of sight of the vehicle driver. 
     The present rear view apparatus uniquely provides the output of one or more rear looking sensors on a vehicle to a heads up display so that rear view information, including video images and other information, are easily visible to the driver in the safe driving line of sight of the driver through the windshield. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The various features, advantages, and other uses of the present invention will become more apparent by referring to the following detailed description and drawing in which: 
         FIG. 1  is a plan view of a vehicle incorporating a rear viewing apparatus and heads up display; 
         FIG. 2  is a side elevational view showing a heads up display mounted on the dashboard of the vehicle; 
         FIG. 3  is a pictorial representation of the projection of a rear view image by the heads up display in the lower portion of the windshield; and 
         FIG. 4  is a block diagram of the components of the rear viewing apparatus. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIGS. 1-4 , there is depicted a rear viewing apparatus incorporated into a vehicle  10 . The rear viewing apparatus  8  includes a heads up display (HUD)  12  mounted on or in the dashboard  16  of the vehicle  10  which is capable of projecting an image in the forward line of sight of the driver. The rear viewing  8  apparatus also includes a rear looking sensor  30  which is capable of providing an output representative of rear view data, such as a video image of the area to the rear of the vehicle, the distance to an object rearward of the vehicle which can be either parametric data or relative distance, the projected path of the vehicle as it travels in reverse, highlighting of the most critical objective interest such as the closest object behind the vehicle, in a video image, and information regarding speed base time to collision with an object behind the vehicle. 
     Such information or data can be obtained by using at least one sensor or a plurality of sensors  30  which can be any of a camera, radar, ultrasonic sensors, LIDAR, infrared, or camera image processing. The sensor or sensors  30  are mounted on the rear of the vehicle  10 . 
     The output of the rear looking sensor or sensors  30  is transmitted to the HUD  12  via a hardwired connection  32  or through a wireless connection  34 . The wireless connection  34  requires a transmitter  36  capable of transmitting the output of the rear looking sensor (s)  30  through an antenna  34  to a similar antenna coupled to a receiver  39  connected to an input of the HUD  12 . 
     The HUD  12  typically includes a video processor, a display unit or image source and a mirror which projects an image which appears to be placed in the windshield  16  of the vehicle  10 . The video processor receives data from the rear looking sensors  30  and formats the data into a suitable display signal that is communicated to the display unit. The video processor can include a digital microprocessor, a memory and related circuitry. 
     As shown in  FIG. 3 , in the case of a video image from a camera acting as the rear looking sensor  30 , a video image is generated by the HUD  12  and projected onto the windshield  14  at a location in the lower portion of the windshield  14  in the driver&#39;s front line of sight. This bottom location is by way of example only, as the HUD  12  can project the image  40  for viewing on other locations in the windshield  14 , such as centered, upper edge, etc. This still allows a driver to view the image  40  while at the same time continuing to look through the windshield when the vehicle is in operation. 
     Other data may also be provided on the image projected by the HUD  12  and displayed within the same window as the video image  40  shown in  FIG. 3 . Any of the rear looking sensor outputs described above can be communicated from the rear looking sensor  30  to the HUD  12  and projected by the HUD  12  into the image window, for example, separate from or as an overlay on the image  40 .