Abstract:
A compass display or a low cost construction includes a display coupled to compass sensing and calibration devices to illuminate a portion of the display to indicate a specific heading. The display is mounted beneath a finish covering surface and includes indicia representing compass directional headings attached or printed thereon and the finish covering is supported by a substrate having a plurality of openings spaced relative to a center point and a plurality of light sources such as LED lights located in the holes of the substrate to be located behind the finish covering and aligned with the directional headings. When a light is illuminated, it is visible behind the finish covering to a driver or other occupant of the vehicle. In a preferred embodiment, twelve openings and associated light sources are provided in the substrate and spaced at 30-degree increments to provide a more precise indication of the vehicle heading. The compass display may be located on the instrument panel, in the headliner, on the A-pillar, on a visor or in any other advantageous location within the passenger compartment. For a movable object like the visor location, a switch is provided to disconnect a power source for the compass display when the visor is moved from its stowed, operating position.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to the field of displays and more particularly to a low cost, convenient compass display for a passenger compartment in a vehicle.  
         BACKGROUND OF THE INVENTION  
         [0002]    A large number of vehicle compass devices and related compass displays are known. Two illustrative examples are shown and described in U.S. Pat. No. 4,953,305 issued Sep. 4, 1990 to Van Lente, et al., for Vehicle Compass With Automatic Continuous Calibration and in U.S. Pat. No. 5,878,370 issued Mar. 2, 1999 to Olson for Vehicle Compass System With Variable Resolution. The compass display disclosed herein is suitable for use with a variety of compass systems, including those using magneto-resistive, magneto-inductive, or other sensing technologies and compass systems configured to operate various automatic and/or continuous calibration algorithms, including those disclosed in the &#39;305 Patent and the &#39;370 Patent, U.S. Pat. Nos. 5,511,319, 5,664,335, 5,737,226, 5,761,094, 6,047,327, and 6,301,794. Such compass products involve a display visible to the driver or other occupants of the vehicle through the instrument panel, on the vehicle overhead console, or in the vehicle rearview mirror. One type of known compass display uses a vacuum florescent display to provide a read out of the compass direction.  
           [0003]    Other compass devices for vehicles are known which are non-electric and simply mount on the instrument panel or other convenient location. The latter type of compass displays tend to be less reliable than electronic compasses which have an automatic calibration capability and display the vehicle heading in a prompt and accurate fashion.  
           [0004]    An obstacle to the inclusion of compasses in nearly all vehicles being manufactured today is cost. In particular, the total cost of the compass includes the cost of the compass sensing components, including microprocessor, application-specific integrated circuit (ASIC), sensors, as well as the cost of the compass display. Typically, complex circuitry is required for the sensing components and has been used as part of the display. The development of a low-cost compass display system, which could be incorporated in a wide range of vehicle types, and which would allow the accuracy of known compass systems without the inherent cost for the display portion would represent a significant advance in the art. Further, the development of a compass display that can be satisfactorily adapted to be installed in alternate locations within the vehicle would also represent a significant advance in the art.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention relates to a low cost compass display that is easy-to-manufacture and of particular use in a vehicle and which may employ, as the operative components of the compass device, known compass technology and includes low cost elements for displaying a referent direction. The compass display according to the present invention is located with respect to a finish covering on the vehicle interior, the finish covering is constructed to allow an illuminated light source to be perceived by a viewer through the finish covering. The light source is controlled by the known compass technology to indicate vehicle heading. The light source of the compass display is preferably a low cost indicator such as a light emitting diode (LED).  
           [0006]    The compass display, in one embodiment, preferably includes a plurality of LED&#39;s positioned about the center of the compass to indicate a heading of the vehicle with respect to a North referent (or other referent if desired) based upon an input from a directional indicator of the known compass technology. Further, the finish covering is preferably a fabric, cloth or other suitable finish material and directional indicators or referent lines are printed, screened or otherwise marked on the finish covering and coordinated with the light source. The directional indicators preferably include at least referent lines representing the directions of North, South, East and West and more detailed directional indicators such as North-East, South-East, South-West and North-West. Preferably, each directional indicator on the finish covering has associated with it a separate LED.  
           [0007]    A switch is preferably centrally or otherwise provided to allow a user to access additional compass functions such as calibration, zone setting or simply on/off features or any other usable feature. The switch is preferably co-located with the compass display at the center of the compass&#39;s directional indicators.  
           [0008]    A feature of the present invention includes a low-cost compass display. Another feature of the present invention includes a compass display which may be easily located at a variety of vehicle interior locations. According to one exemplary embodiment, the cost of the compass display is reduced by using low-cost LEDs instead of a reconfigurable display, such as a vacuum-fluorescent display, liquid crystal display, or other more complex display technology. According to another exemplary embodiment, the cost of the compass display is reduced by using a simple LED-driver circuit instead of a display driver circuit for a reconfigurable display. For example, a vacuum-fluorescent display (VFD) requires a filament that glows in response to a pulsed power signal. The components required to provide this pulsed power signal add cost to the display. Further, automotive VFDs are required to operate over a range of voltages, such as 9-16 Volts. A 12-Volt regulator and several large electrolytic capacitors are required to meet this requirement, which adds further cost to the display.  
           [0009]    A further feature of the present invention includes a compass display which may be used at a variety of vehicle interior locations such as a vehicle visor which display is preferably disconnected from a power source when the visor is moved from a stowed location. A still further feature of the present invention includes a vehicle compass display which may be used with a variety of vehicle coverings, including fabric, cloth, leather, vinyl or any other suitable finish covering. Another feature of the present invention is the provision of a compass display which is easy to manufacture, which is reliable and which provides information to the driver or other vehicle occupants in a convenient and accurate fashion.  
           [0010]    How these and other features of the present invention are accomplished will be described in the following detailed description of the preferred embodiment, taken generally in conjunction with the Figures. Generally, however, the above features are provided by locating an LED display with respect to a finish covering of a portion of the vehicle interior, such as the visor, instrument panel, A pillar, overhead liner or other location. Preferably, the LED&#39;s are positioned in an opening in a substrate below the finish covering, and arranged to designate directional points about the compass. Preferably, a plurality of light sources includes eight light sources or LED&#39;s spaced around a central point of the compass. The light sources correspond to directional indicators designating North, East, South and West headings and the compass designations located there between, i.e., North-East, South-East, South-West and North-West. Any other combination of directions may be desirable.  
           [0011]    Preferably, the LED display of the present invention is activated when the vehicle ignition is turned to the on position or when it is turned to the accessory position. Alternatively, a switch may be provided to be turned on at the option of the driver and to access other functions such as calibration and zone setting. The compass display of the present invention is preferably viewable by the vehicle operator and vehicle occupants, but may be positioned in any manner to be viewable by some or all occupants. In a further alternative embodiment, it is possible for the compass display to be used independently.  
           [0012]    In a most preferred embodiment, the compass display of the present invention is located on a surface of a visor in front of the driver&#39;s position in an automobile and a power source for illuminating the light source in the visor is designed to turn off when the visor is moved from a normal stowed position, such as when the visor is moved to either a lowered position or moved to prevent sun from entering a side window. By turning off the compass when the visor is moved from the stowed position, calibration errors are reduced or eliminated such that the compass display and compass sensor may be combined in a unit and mounted within the movable visor.  
           [0013]    Alternatives to the features of the invention will be apparent to those skilled in the art after reviewing the present application, such other ways falling within the scope of the present invention if they fall within the scope of the claims which follow. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a partial perspective view of an interior of a vehicle having a visor including a compass display according to the present invention.  
         [0015]    [0015]FIG. 2 is a partial, perspective cross section view of the visor including the compass display according to the present invention taken along the line  8 - 8  of FIG. 1.  
         [0016]    [0016]FIG. 3 is an alternate exploded assembly view of the visor of FIG. 1 including a compass display according to the present invention.  
         [0017]    [0017]FIG. 4 is a partial perspective view of the visor of FIG. 1 showing a deactivation switch for the compass display according to the present invention.  
         [0018]    [0018]FIG. 5 is a partial perspective view of a deactivation switch for the compass display of the present invention in a first position.  
         [0019]    [0019]FIG. 6 is a partial perspective view of the visor of FIG. 1 showing the deactivation switch in a second position for the compass display of the present invention.  
         [0020]    [0020]FIG. 7 is a partial perspective view of the deactivation switch in a second position for the compass display according to the present invention.  
         [0021]    [0021]FIG. 8 is an exploded assembly perspective view of the visor of FIG. 1 including the compass display according to the present invention.  
         [0022]    [0022]FIG. 9 is a perspective view of a visor for use in a vehicle, the visor including a compass display according to the present invention.  
         [0023]    [0023]FIG. 10 is a partial perspective view of an interior of a vehicle having a headliner including the compass display according to the present invention.  
         [0024]    [0024]FIG. 11 is a partial perspective view of an interior of a vehicle having a dash board including a compass display according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    Referring generally to the figures and in particular to FIG. 1 and FIG. 2, there is shown a compass display  10  for use in a passenger compartment  100  of a vehicle  110 . The compass display  10  relates to a compass assembly or unit  20  preferably installed in a visor  120  that is connected to a roof or headliner  140  of the vehicle  110 . The visor  120  is preferably mounted to the headliner  140  using a pivot rod assembly  180  more fully described below or any other known or appropriate assembly for securing the visor  120  to the headliner  140 . The visor  120  preferably includes a display or first side  121  which is viewable when the visor  120  is in a stowed position as shown in FIG. 9 and a second side  123  preferably opposite the first side  121 .  
         [0026]    The visor  120  is preferably constructed using any known or appropriate combination of materials and construction such as using the materials and a method similar to U.S. Pat. No. 5,860,690, the disclosure of which is incorporated herein by reference  
         [0027]    Referring to FIGS. 2 and 3, the compass unit  20  and display  10  are, in a preferred embodiment, incorporated into the visor  120  such that the display  10  is usable by the occupants of the vehicle to determine the heading of the vehicle with respect to a referent such as north. The compass unit  20  preferably includes the necessary electronics to generate a signal for indicating a heading such as those that are commonly used in vehicles.  
         [0028]    The compass unit  20  can include magneto-resistive, magneto-inductive, or other sensors configured to measure the Earth&#39;s magnetic field. The compass unit  20  can further include a control or processing circuit configured to receive signals from the sensors (e.g., via an application-specific integrated circuit or ASIC) and to perform one or more automatic and/or continuous calibration algorithms. For example, the control circuit can be configured to operate one or more of the automatic continuous calibration methods disclosed in U.S. Pat. No. 4,953,305, which is herein incorporated by reference. Further, the control circuit can be configured to operate one or more of the automatic calibration methods disclosed in U.S. Pat. No. 5,737,226, which is herein incorporated by reference. Further still, the control circuit can be configured to vary the system&#39;s sensitivity resolution as disclosed in U.S. Pat. No. 5,878,370, which is herein incorporated by reference.  
         [0029]    The compass unit  20  is located in a receptacle  122  formed in a core  124  of the visor  120  by a wall  125 . The core  124  is preferably made from a thermoformed material and the wall  125  defining the space  122  is preferably integrally formed in the core  124  in any appropriate manner or fashion. However, the space  122  may be formed using any known material or process and in any alternative or appropriate form or shape to correspond to and hold the compass unit  20 . The core  124  is preferably made from a thermoformed material more particularly, the core  124  is preferably formed from a thermoformed polypropylene material, which functions as a core of the visor  120 . The core  124  is preferably formed into a first core portion  126  and a second core portion  127  which are separated by and can be folded along a fold line  128  which is preferably a living hinge in the middle portion of the core  124  such that the first core portion  126  and second core portion  127  are essentially mirror images of each other.  
         [0030]    The compass unit  20  is preferably held in the space  122  between the layer portion  126  and layer portion  127  of the integrally formed layer  124  when the layer portions  126  and  127  are closed, the compass unit  20  is trapped between the layer portion  126  and  127  and by the wall  125 . Alternatively, a connector (not pictured) may be used to clip or otherwise fasten and securely hold the compass unit  20  within the space  122  and allow the compass display  10  to be appropriately secured to and positioned in the interior structure of the visor  120 . Other amenity items such as a mirror or mail holder (not shown) and the similar may also be added to the visor  120  as may be preferred for a given application. The wall  125  is shown as a projection from the layer portion  126  as being a continuous section having a break in one end. It should be understood that the wall  125  may have varying shapes and forms and may be continuous or discontinuous and may include additional elements provided the wall  125  holds the compass unit  20  in position between the partial layer  126  and partial layer  127 .  
         [0031]    The pivot rod  182  is also held in position between the first core portion  126  and second  127  similar to the compass unit  20 . The pivot rod  182  of the pivot rod assembly  180  is received in a sleeve or carrier  184 . The detent spring  184  functions to retain the pivot rod  182  within a channel  132  in the layer  126 . The channel  132  is further defined by the wall  129 , similar to channel  128 . The sleeve  184  located/retained in channel and sandwiched between core portions defining the channel  132  such that the sleeve  184  retains the rod  182  on the layer portion  126 .  
         [0032]    Further, the rod  182  is received within the sleeve  184  in frictional engagement such that the sleeve  184  allows the visor  120  to pivot on the rod  182  in a controlled manner such that the visor  120  will not move without the application of a predefined amount of force and the visor  120  will maintain its set position under normal operating conditions of the vehicle. Detents it in the stowed position which holds visor  120  in secured position.  
         [0033]    Referring to FIG. 3 through FIG. 7. Since the compass unit  20 , according to one exemplary embodiment, is intended to indicate the direction heading of the vehicle, the compass unit  20  and compass display  10  are designed to function only when the visor  120  is in the stored position, which preferably aligns the compass unit  20  with the longitudinal direction of the vehicle  110  as shown in FIG. 1. This avoids the significant costs associated with including automatic calibration hardware. Alternatively, a position sensor can be coupled to visor  120  and configured to detect the position of visor  120 . Compass unit  20  can then compensate the directional signal for changes in position of visor  120 . One suitable system is disclosed in U.S. application Ser. No. 09/651,521 entitled “Method and Apparatus to Maintain Compass Heading with a Moveable Sensor Mounting” to Thomas R. Olson, filed Aug. 30, 2000, which is herein incorporated by reference.  
         [0034]    The wiring harness  150  includes the wires  152 ,  153  and  155  and the switch  158  for deactivating the compass unit  20  and compass display  10  when the visor  120  is moved from the stowed position.  
         [0035]    The switch  158  is positioned and aligned within partial layer  126  of the visor core  124  in a channel  128  defined by a wall  129 . The switch  158  includes a follower contact  159  which is preferably spring loaded and biased in an outward direction from the switch  158  for contact with a portion of a pivot rod  182  of the pivot rod assembly  180 .  
         [0036]    The sleeve  184  and pivot rod  182  are located proximate the switch  158  such that the switch  158  is aligned with a flat  192  on the pivot rod  182  as shown in FIG. 4 through FIG. 7. The flat  192  of the pivot rod  182  is designed to co-act with the follower contact  159  of the switch  158 . When the visor  120  is rotated from the stowed position on the pivot rod  182  which remains stationary, the follower contact  159  of the switch  158  aligns with the flat  192  of the pivot rod  182  allowing the follower contact  159  to be biased outward from the switch  158  thereby opening the switch  158  and turning off the compass unit  20  and the compass display  10 . This feature prevents the necessity to have to recalibrate the compass unit  20  and compass display  10  each time the visor  120  is moved from the stowed position.  
         [0037]    It should be understood by a person of ordinary skill in the art that while the switch  158  is shown as co-acting with the periphery of the pivot rod  182  to switch the power to the compass unit  20 , it is possible that any other known or appropriate switch or power interruption device may be used for turning off the compass unit  20  and compass display  10  when the visor  120  is moved from the stowed position.  
         [0038]    Further, it is possible to provide a separate compass on/off switch (not shown) that is not automatically activated by the movement of the visor  120 . For example, a switch can be provided separately for example on the face of the visor  120  that a user can manually activate. The same switch or a second switch can be provided as a mode switch to switch between various modes of the compass display device.  
         [0039]    Referring to FIG. 8, the compass assembly  20  further includes a plurality of lights  22  arranged to correspond with the referents of the compass unit  20 . While the present invention preferably includes eight lights  22  in the plurality of lights, it should be understood by a person of ordinary skill in the art that it is possible that the compass unit  20  of the present invention include a single light  22  or any number of lights depending upon the resolution desired in the referents of the compass unit  20 . Each light  22  of the plurality of lights  23  align with a respective hole  26  in a housing  24  of the compass unit  20 . Similarly, each light  22  of the plurality of lights  23  also preferably aligns with a respective hole  136  of the visor core  124 . Accordingly, when the visor  120  is in the stowed position and a light  22  of the plurality of lights  23  is powered to indicate the heading direction by having the compass system energize the light  22 , the occupant of the vehicle  110  can perceive that the light  22  is lit.  
         [0040]    Referring to FIG. 6, the pivot rod assembly  180  further includes an elbow  186  connected to an end of the pivot rod  182 . A mount or connector  188  is connected to the elbow  186  using any known or appropriate connecting means such as glue, staking, fasteners, threaded connectors or the like as may be appropriate for connecting the elbow  186  to the pivot rod  182  and maintain the relative movement for proper functioning of the visor  120 . The other end of the elbow  186  may be fixedly or permanently connected to the mount  188  but is preferably pivotally connected thereto. The mount  188  includes holes  190  for mounting the visor  120  to the interior of the vehicle  110  in a manner well known in the art but may be attached using any known or appropriate connector design. The connector  188  has the wires  152  and  153  passing through the elbow  186  and extending therefrom to the connector  156 .  
         [0041]    The compass unit  20  has power supplied to it by a wiring harness  150  or any other known or appropriate device for supplying an appropriate level and condition of power to the compass unit  20 . The wiring harness  150  includes wires  152  and wire  153  and a connector  154  to connect the wires  152  of the wiring harness  150  to the compass unit  20 . The wires  152  and the wire  153  are routed in any known or appropriate manner to pass within the visor  120  and through the pivot rod  182  of the pivot rod assembly  180  to a second connector  156  for connection of the compass unit  20  to the vehicle&#39;s power supply and CPU (not shown). The wiring harness  150  connects with the vehicle&#39;s power system to supply the level and condition of power needed for the compass unit  20  and the compass display  10  to function properly.  
         [0042]    In an alternate embodiment, as shown in FIG. 10, the compass display  10  and the compass unit  20  are incorporated in the headliner  140  of the vehicle  110  such that the compass display  10  can still be perceived by an occupant in the passenger compartment  100 . In the embodiment of FIG. 10, the finish cover  130  preferably forms the interior finishing of the headliner  140 . In a further embodiment of the present invention, as shown in FIG. 11, the compass display  10  is incorporated in a dash board  144  in the passenger compartment  100  of the vehicle  110 , such that an occupant of the vehicle and preferably the driver may view the compass display  10 . In all of the embodiments shown, the compass display  10  preferably includes a set of compass referent directions  14  printed or screened on the respective materials which comprises either the first surface of the compass display  10  such as the housing  24  or first layer  126  of the visor  120  or on the finish cover  130  of the visor  120 , headliner  140  or dash board  144 , respectively. In the embodiments shown, the compass referent directions  14  preferably include eight (8) referent directions including north, northeast, east, southeast, south, southwest, west, and northwest. It is should be understood that it is possible for the referent directions  14  to include only one referent corresponding to a direction or as many referents as desired depending upon the desired resolution for the compass display  10  and the number of lights  22 . Further, it should be understood that while eight (8) referent directions  14  and respective referent lines  16  are shown in the embodiments described herein and eight (8) corresponding lights  22  are shown, it is possible for the compass display  10  to include fewer or greater referent directions than lights  22 .  
         [0043]    Referring to FIGS. 10 and 11, the visor  120  of the preferred embodiment further preferably includes a surface covering or finish cover  130  that covers the exterior side of the layer  124  to provide alternative aesthetic trim surfaces, if desired. Preferably, the visor  120  is provided with a finish cover  130  and the occupant of the vehicle  110  can still perceive the light  22  as being lit from within passenger compartment of the vehicle during normal operating conditions since such finish cover  130  is preferably light transmissive. The cover  130  is preferably made from any known or appropriate fabric material suitable to allow an illuminated light source such as light  22  to be viewed through the cover  30  but may be made using any known and appropriate material such as fabric, cloth, vinyl, plastic, polymeric, leather, etc. Alternatively, a finish cover  130  that is not sufficiently light transmissive can be selected and a hole (not shown) is provided in the finish cover  130  for allowing the light  22  aligned with respect to such hole to be perceived by the occupant of the vehicle  110 . If the finish cover  130  is made from an opaque or relatively low light-transmissive material such as plastic, polymeric, leather or a “backed” or “tight-weave” fabric, the hole or other element maybe provided in the finish cover  130  to allow light emitted from a light  22  to be perceived on the first side  121  of the visor  120 .  
         [0044]    It is understood that while the drawings and specific examples provided describe in detail the preferred embodiments of the present invention, they only serve an illustrative purpose. The apparatus of the invention is not limited to the precise details and conditions disclosed. For example, the compass display can be adapted or configured for compatibility with other finish coverings of different materials, to be located in other types of vehicles and also to satisfy the design standards of a wide variety of automobile manufacturers. A further alternative example contemplated hereby would be to include a template beneath the finish covering as an alternative to the visor core. The template could be a separate piece that is snap connected to the finish cover and has a patterned hole or other cutout such as in the shape of a letter. Additionally, it is possible to have shaped LEDs in the form of letters to represent the referent directions of the compass.  
         [0045]    Further, although particular shapes and relative dimensions have been shown, various other shapes, geometry and dimensions could be utilized for the various components. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and method of manufacturing the apparatus of the preferred embodiments without departing from the spirit of the invention as expressed in the appended claims.