Abstract:
An automatic sun visor system for a vehicle includes a light detecting apparatus for detecting sunlight incident upon the face of an occupant of the vehicle. A microcontroller receives a control signal from the light detecting apparatus, and an adjustable sun visor receives a darkening control signal from the microcontroller. The darkening control signal activates the adjustable sun visor in response to the degree of sunlight detected.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a divisional of U.S. patent application, Ser. No. 10/324,588, entitled “AUTOMATIC SUN VISOR AND SOLAR SHADE SYSTEM FOR VEHICLES”, filed Dec. 19, 2002, now U.S. Pat. No. 6,666,493 which is incorporated herein by reference. 
    
    
     BACKGROUND 
     The present disclosure relates generally to sunlight blocking devices and, more particularly, to a self-adjusting, automatic sun visor and solar shade system for vehicles that determines the blocking needs of an individual driver. 
     One traditional way of shading a driver&#39;s eyes from sunlight is through a manually operated sun visor attached to the interior headliner of a vehicle. The sun visor may be manually folded downward and positioned to shield the driver&#39;s eyes from sunlight shining in through the front windshield. Typically, the sun visor may also pivot with respect to the longitudinal axis of the vehicle so that the driver can use the visor to block sunlight that is shining in the driver side door window. In either case, however, the driver must manually position the visor. Moreover, a manual visor does not function to block out sunlight shining through the vehicle&#39;s passenger side front windshield or side door. Thus, in order to shade out the light from that area, a driver has to manually position the passenger side sun visor. 
     Mechanically activated sun visor devices have also been developed. One such device includes a motorized sun visor that can be activated and positioned by the driver pressing an actuator button. The visor itself is made of material that is rolled onto a drum that is connected to a motor. Depending on the commands inputted by the driver, the motor causes the visor material to be unrolled or rolled up. With such a system, however, there is no way of automatically positioning the sun visor based on the quantity of light contacting the driver&#39;s eyes. In addition, the system does not provide a way of blocking sunlight that is entering through the driver or passenger side windows of the vehicle. 
     Still another device that has been developed describes an electronically controlled visor that uses liquid crystal pixels configured inside of the window to shade out sunlight. The visor is activated by a light sensor that detects the angle and incidence of light. When the pixels are activated they will shade out some of the light while still allowing the visor to be transparent. 
     SUMMARY 
     In an exemplary embodiment, an automatic sun visor system for a vehicle includes a light detecting apparatus for detecting sunlight incident upon the face of an occupant of the vehicle. A microcontroller receives a control signal from the light detecting apparatus, and an adjustable sun visor receives a darkening control signal from the microcontroller. The darkening control signal activates the adjustable sun visor in response to the degree of sunlight detected. 
     In another embodiment, an automatic sun visor system for a vehicle includes at least one infrared camera aimed toward the headrest of the driver&#39;s seat of the vehicle. A microcontroller is connected to the at least one infrared camera, and a first sun visor is connected to the microcontroller. The first sun visor is capable of shading light shining in through the driver side of the front windshield. In addition, a second sun visor is connected to the microcontroller, and is capable of shading light shining in through the passenger side of the front windshield. 
     In still another embodiment, a method for automatically operating a vehicle sun visor includes detecting the amount of light shining through the windows of the vehicle and onto the face of a vehicle occupant. The detected amount of light is compared to a desired reference amount, and a control signal is applied to adjust the vehicle sun visor such that the actual amount of light incident onto the face of the vehicle occupant is in agreement with the desired reference amount of light. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the exemplary drawings wherein like elements are numbered alike in the several Figures: 
     FIGS.  1 ( a ) and  1 ( b ) illustrate a schematic diagram of a vehicular sun visor system, in accordance with an embodiment of the invention; 
     FIG. 2 is a schematic block diagram of the sun visor system of FIG. 1; 
     FIG. 3 is a schematic diagram illustrating the operation of an electrochromic embodiment of the sun visor system; 
     FIG. 4 is a perspective view of the electrochromic sun visor embodiment implemented in a motor vehicle; 
     FIG. 5 is a perspective view of a mechanical fold down embodiment of the sun visor system; and 
     FIG. 6 is a perspective view of a mechanical roll down embodiment of the sun visor system. 
    
    
     DETAILED DESCRIPTION 
     Referring initially to FIGS.  1 ( a ) and  1 ( b ), there is shown a schematic diagram of one embodiment of a vehicular sun visor system  10 . The sun visor system  10  includes a digital camera  16  that faces inward toward the face  18  of the driver of a vehicle (not shown). The digital camera  16  is connected to and sends a video signal to a microcontroller  20 . The microcontroller  20  is in turn connected to an electrochromic visor  22  that is placed across the surface of the front windshield  14  of the vehicle. 
     As is well known in the art, an electrochromatic device is one in which a reversible color change of a material is caused by the application of an electrical current or potential. The electrochromic visor  22  may rest against the surface of windshield  14 , or it may be formed inside of windshield  14 . When a predetermined amount of sunlight  24  shines through windshield  14  or other windows of the vehicle, the digital camera  16  signals the microcontroller  20  to activate electrochromic visor  22  to respond by shading out a portion of the sunlight  24  shining in windshield  14  of the vehicle. 
     It should be noted that the electrochromic visor  22  is but one example of a device that may be used to carry out the darkening/shading function in response to detected sunlight. For example, a liquid crystal device or other device responsive to electrical current may be used to provide darkening. In addition, an electrically operated, motor driven shading apparatus may also be used to provide the desired shading, as will be explained in greater detail hereinafter. 
     FIG. 2 is a block diagram illustrating a particular method of sunlight detection and activation of the sun visor system  10  of FIG.  1 . Like elements of the system  10  shown in FIG. 1 are similarly designated in FIG.  2 . Again, the digital camera  16  is pointed toward the face  18  of the driver of the vehicle. Specifically, the digital camera  16  detects the amount of sunlight  24  reaching the driver&#39;s face  18  as defined by shadow line  26 . The readings taken by the digital camera  16  are provided to the microcontroller  20  by a control signal  28 , which may be representative of a measurement-based estimate of the shadow line  26  across the driver&#39;s face  18 . The microcontroller  20  compares the control signal  28  with a reference shadow line signal  29  intended to keep the shadow line  24  below the driver&#39;s eyes. Thus, if a designated amount of sunlight  24  reaches the driver&#39;s face  18  the electrochromic visor  22  is activated by a darkening control signal  30  sent from microcontroller  20 . The darkening control signal  30  causes the shading intensity of the visor  22  to be increased or decreased, based upon on measurements of the shadow line  26  on driver&#39;s face  18 . 
     FIG. 3 is a schematic diagram illustrating the operation of the electrochromic sun visor  22  shown in FIGS. 1 and 2. In this particular embodiment, the electrochromic sun visor  22  is depicted as having a series of five horizontally disposed panels  32  arranged adjacent to each other in a vertically stacked fashion. It will be appreciated, however, that the electrochromic sun visor  22  can also be arranged to have a different number of horizontal panels  32 . The panels  32  could also be arranged in a different spatial orientation (e.g., vertical or circular panels), depending on factors such as the direction of light or the placement of the electrochromic visor  22  on other windows in the vehicle. Each panel  32  (designated individually as segment  1  through segment  5 ) is coupled to a supply voltage  33  through a corresponding transistor  35 . 
     The switching of each transistor is controlled through the darkening control signal  30 . However, beginning from the top segment (segment  1 ), the corresponding transistor coupled to each successive segment has a progressively higher threshold voltage. Thus configured, the specific magnitude of the darkening control signal  30  (which may range, for example, between 0 volts (V) and 5V), will determine how may panels  32 , if any, of the electrochromic sun visor  22  are darkened. 
     Accordingly, the first horizontal panel  34  (segment  1 ) is coupled to a corresponding transistor having threshold voltage of just greater than 0 V, the second horizontal panel  36  (segment  2 ) is coupled to a corresponding transistor having threshold voltage of just greater than 1 V, the third horizontal panel  38  (segment  3 ) is coupled to a corresponding transistor having threshold voltage of just greater than 2 V, the fourth horizontal panel  40  (segment  4 ) is coupled to a corresponding transistor having threshold voltage of just greater than 3 V, and the fifth horizontal panel  42  (segment  5 ) is coupled to a corresponding transistor having threshold voltage of just greater than 4 V. In the example illustrated, the value of the control signal is 1.5 V. Because this exceeds the threshold value of the transistors coupled to segments  1  and  2 , those segments are darkened. However, since the threshold value of the transistors coupled to the remaining segments is greater than 2.0 V, the segments are not darkened. If the value of the darkening control signal  30  were to subsequently be increased to 2.5 volts, for example, then segment  3  would also become darkened. 
     When any of the five panels  32  of electrochromic visor  22  are darkened, they will still be translucent. This allows the driver to still be able to see through the visor  22  while, at the same time, bright sunshine is shaded out. Although FIG. 3 shows the five panels  32  as having either a dark, shaded mode or a clear, unshaded mode it should be understood that it is possible to utilize an electrochromic visor  22  that has one or more intermediate ranges of shading for such applications as shading out less intense light such as sunlight on cloudy days, or shading out bright headlights that are encountered at night. 
     Referring now to FIG. 4, there is shown a perspective view of another electrochromic embodiment of the vehicular sun visor system  10  arranged within the interior of a motor vehicle. As is shown, the system  10  includes four individual electrochromic sun visors that darken in response to heat readings on the driver&#39;s face  18  taken with four individual infrared cameras. A driver side front windshield visor  46  is mounted to a front windshield  50 . Associated therewith is driver side front windshield camera  48  mounted to the driver side I-pillar  51  located adjacent to the front windshield  50 . Camera  48  is configured to receive heat readings that will activate or deactivate the driver side front windshield visor  46 . 
     Similarly, a passenger side front windshield visor  52  is mounted to front windshield  50 , and is associated with a passenger side front windshield camera  54  mounted to the passenger side I-pillar located adjacent to the front windshield  50 . Camera  54  is configured to receive heat readings that will activate or deactivate passenger side front windshield visor  52 . In addition, a driver side window visor  56  (mounted to a driver side window  58 ) and a passenger side window visor  60  (mounted to a passenger side window  62 ) are associated with a driver side window camera  61  (mounted to a headliner  76  above the driver side window  58 ) and a passenger side window camera  64  (mounted to a headliner above the passenger side window  62 ), respectively. 
     Each of the four infrared cameras  48 ,  54 ,  61 , and  64  sends corresponding control signals  28  to a microcontroller  20 . In this illustrative embodiment, the microcontroller  20  is depicted as being positioned inside of headliner  76  of the vehicle. However, the microcontroller  20  could also be positioned in other areas of the vehicle interior such as in the instrument panel or in the side door housing of the vehicle, depending on the spatial availability of a particular vehicle model. In response to the heat signals from infrared cameras  48 ,  54 ,  61 , and  64 , the microcontroller  20  may transmit an appropriate darkening control signal  30  to one or more of the electrochromic visors  46 ,  52 ,  56 , and  60 . Of course, subsequent adjustments to the shading of the electrochromic visors  46 ,  52 ,  56 , and  60  are made whenever new heat signals  28  are sent to the microcontroller  20 . 
     While this particular embodiment incorporates only one microcontroller, it is possible to use more than one microcontroller based on the individual needs of a particular application. For instance, it may be the case that better results are achieved using more than one microcontroller in order to have more control over which electrochromic visors are darkened. It may also prove to be more cost effective to incorporate more than one microcontroller as opposed to having just one main microcontroller. 
     FIG. 5 is a perspective view of a mechanical fold down embodiment of the vehicular sun visor system  10  arranged within the interior of a motor vehicle, in which like elements appearing in FIG. 5 are designated with the same reference numerals as in the previous figures. In addition, the particular method of sending heat signals  28  from infrared cameras  48 ,  54 ,  61 , and  64  to microcontroller  20  in the illustrated embodiment, as well as sending a control signal  30  from microcontroller  20  to a particular visor is the same as described in FIG.  4 . However, instead of electrochromic visors, the embodiment of FIG. 5 implements a pair of motorized fold down sun visors. 
     The pair of motorized fold down sun visors includes a driver side visor  68  and a passenger side visor  70 . The driver side visor  68  is movably coupled to an electrically operated motor  72  mounted to headliner  76 , while the passenger side visor  70  is movably coupled to an electrically operated motor  74  mounted to headliner  76 . Both the driver side visor  68  and the passenger side visor  70  are generally opaque so as to prevent light from passing through. 
     Specifically, the motors  72 ,  74  are configured to receive a darkening control signal  30  from microcontroller  20  as a control input thereto, and are responsible for folding down visors  68 ,  70  from a resting position against the headliner  76  to a shading position in front of the interior side of front windshield  50 . In addition, the motors  72 ,  74  can also cause visors  68 ,  70  to pivot and translate to a second blocking position  78 ,  80  that is depicted in FIG. 5 as a ghost outline. When the visors  68 ,  70  are in their respective second blocking positions  78 ,  80 , sunlight is prevented from coming in through the driver side and passenger side windows  58 ,  62 . The particular fold angle of visors  68 ,  70  may be adjusted through control signals issued by the microcontroller  20 . The adjustment of the fold angle of visors  68 ,  70  will accordingly change the position of the shadow line, which is detected with either infrared or digital cameras, directed at the face of the driver. 
     Finally, FIG. 6 is a perspective view of a mechanical roll down embodiment of the vehicular sun visor system  10  arranged within the interior of a motor vehicle, in which like elements appearing in FIG. 6 are designated with the same reference numerals as in the previous figures. Once again, the particular method of sending heat signals  28  from infrared cameras  48 ,  54 ,  61 , and  64  to microcontroller  20  in the illustrated embodiment, as well as sending a control signal  30  from microcontroller  20  to a particular visor is the same as described in FIGS. 4 and 5. However, instead of electrochromic visors or a mechanical fold visors, the embodiment of FIG. 6 implements a pair of motorized roll down sun visors. 
     The pair of motorized roll down sun visors includes a driver side windshield roll down visor  82 , a passenger side windshield roll down visor  84 , driver side window roll down visor  86 , and a passenger side window roll down visor  88 . Each of the visors includes a motorized drum (not shown) having a shade  90  rolled thereupon. Each shade  90  is also preferably constructed of a generally opaque material suitable for blocking out light. The mounting of each roll down visor is similar to that shown for the fold down visors of FIG.  5 . Moreover, the roll down embodiment also includes cameras for each visor that detect heat or light incident upon the driver&#39;s face, so as to generate an appropriate signal to the microcontroller  20 . 
     The four infrared cameras  48 ,  54 ,  61 ,  64  depicted in the embodiments of FIGS. 4-6 are positioned such that they view the driver&#39;s face  18  at an angle that is relative to the angle of incident light in order to enable each of the visors to block light. Although the embodiments described above use four infrared cameras, it is also possible to use a lesser number of cameras. For example, imaging software can analyze the angle and intensity of light reaching the driver&#39;s face such that the system can determine the proper visor position to activate. It is also possible to control the degree of shading needed based on the heat readings taken using the infrared cameras. Additionally, such applications will enable the system to be used to shade any sunlight present on cloudy days, or light generated by the oncoming headlights of other vehicles. Although each of the visor arrangements in FIGS. 4-6 depict using a specific number of visors, it is also contemplated that the system could provide desired sun blocking coverage by using a lesser or greater number of visors. 
     While the invention has been described with reference to a preferred embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.