Abstract:
A gauge has a face plate which includes indicia thereon to indicate specific values of a parameter. A laser system is disposed behind and/or in front of the face plate to project a beam onto the face plate to indicate the value of a parameter. A stepper motor moves the beam based upon the output of a sensor which monitors the parameter.

Description:
FIELD 
   The present disclosure relates to gauges such as instrument panel gauges for an automobile. More particularly, the present disclosure relates to gauges which have a laser pointer which indicates the value being displayed by the gauge. 
   BACKGROUND 
   The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
   Gauges are utilized throughout industry to display a value of a parameter being monitored by the gauge. In the automotive industry, a plurality of gauges are located on the instrument panel or dashboard for displaying information relating to the operating conditions of the vehicle. These gauges include, but are not limited to, speedometers, tachometers, engine coolant temperature, engine oil temperature, fuel level, oil pressure, battery voltage and the like. The gauges can include an analog and/or digital readout for displaying the valve of the monitored parameter depending upon the design of the specific gauge. An analog gauge typically includes a face plate of some type having indicia thereon such as numbers, letters or indicators. A pointer rotates or traverses across the face plate and is positioned or stops on the face plate at the point which indicates the value of the parameter being monitored. 
   SUMMARY 
   A gauge includes a face plate having indicia thereon to indicate specific values of a parameter. A laser system is disposed behind or in front of the face plate. The laser system projects a beam onto the face plate to indicate the value of the monitored parameter. The laser system includes a driving device which receives an input from the monitored parameter and based upon this input the driving device moves the beam into the proper position for indicating the specific value of the parameter. 
   Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 

   
     DRAWINGS 
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       FIG. 1  is a perspective view of an instrument cluster of a typical automotive vehicle; 
       FIG. 2  is a front view of the speedometer which is located on the instrument cluster illustrated in  FIG. 1 ; 
       FIG. 3  is a schematic side view of the speedometer illustrated in  FIG. 2 ; 
       FIG. 4  is a front view of a speedometer according to another embodiment of the present invention; and 
       FIG. 5  is a schematic side view of the speedometer illustrated in  FIG. 4 . 
   

   DETAILED DESCRIPTION 
   The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     FIG. 1  illustrates a typical interior  10  for an automotive vehicle. The interior includes vehicle seating  12 , a dashboard  14 , a steering wheel  16  and an instrument cluster  18 . While  FIG. 1  illustrates a left-hand drive vehicle, the present disclosure also applies to right-hand drive vehicles. 
   Instrument cluster  18  includes a plurality of gauges typically including a gauge  20  which is illustrated as a speedometer. While the present disclosure is being described using speedometer  20  as the gauge, it is to be understood that any other gauge including, but not limited to, tachometers, engine coolant temperature, engine oil temperature, fuel level, oil pressure, battery voltage and the like can also incorporate the features described for speedometer  20 . 
   Referring now to  FIGS. 2 and 3 , speedometer  20  is illustrated in greater detail. Speedometer  20  comprises a face plate  30  and a laser indicating system  32 . Face plate  30  includes a base plate  34  and a plurality of indicators or indicia  36 . Base plate  34  is a circular disc having the plurality of indicators  36  located along an outer circumferential portion of base plate  34 . While base plate  34  is illustrated as a circular disc, it is within the scope of the present disclosure to have other shapes for base plate  34  including, but not limited to oval and rectangular. 
   The plurality of indicators  36  are arranged in ascending order to indicate the speed of the vehicle. The plurality of indicators  36  can represent miles per hour, kilometers per hour or both. While the plurality of indicators  36  are illustrated as indicating the speed of the vehicle, the plurality of indicators  36  can indicate any set of values monitored by gauge  20 . 
   Laser indicating system  32  comprises a first printed circuit board  40 , a second printed circuit board  42 , a laser diode  44 , a rotating reflector  46  and a stepper motor  48 . First printed circuit board  40  is mounted behind face plate  30 . Second printed circuit board  42  is mounted between first printed circuit board  40  and face plate  30 . A connector  50  mechanically connects second circuit board  42  to first circuit board  40 . Connector  50  can also provide the electrical connection between second circuit board  42  and first circuit board  40  or a separate electrical connection can be made. 
   Laser diode  44  emits a beam  52  from second circuit board  42  towards first circuit board  40 . Rotating reflector  46  is mounted to stepper motor  48  which is mounted to first circuit board  40 . Beam  52  emitted by laser diode  44  is reflected and shaped by rotating reflector  46  so that a generally linear or plate  30  allows transmission of beam  54  from rotating reflector  46  through base plate  34  at a position radially inward and/or at the same radial position of the plurality of indicators  36 . Stepper motor  48  electrically communicates with a sensor  56  which transmits an electrical signal indicating the speed of the vehicle. Stepper motor  48  rotates rotating reflector  46  which, in turn, moves reflected beam  54  circumferentially around face plate  30  in order to place reflected beam  54  adjacent the specific indicator  36  for indicating the current speed of the vehicle. While reflected beam  54  is being described as a linear or rectangular beam, it is within the scope of the present invention to have reflected beam  54  be any shape which can indicate the speed of the vehicle. 
   Referring now to  FIGS. 4 and 5 , a gauge in the form of a speedometer  120  is illustrated. Speedometer  120  is a direct replacement for speedometer  20  in instrument cluster  18 . Speedometer  120  comprises a face plate  130  and a laser indicating system  132 . 
   Face plate  130  includes a base plate  134  and a plurality of indicators or indicia  136 . Base plate  134  is a circular disk having the plurality of indicators  136  located along an outer circumferential portion of base plate  134 . While base plate  134  is illustrated as a circular disk, it is within the scope of the present disclosure to have other shapes for base plate  134  including but not limited to oval and rectangular. 
   The plurality of indicators  136  are arranged in ascending order to indicate the speed of the vehicle. The plurality of indicators  136  can represent miles per hour, kilometers per hour or both. While the plurality of indicators  136  miles per hour, kilometers per hour or both. While the plurality of indicators  136  are illustrated as indicating the speed of the vehicle, the plurality of indicators  136  can indicate any set of values monitored by gauge  120 . Base plate  134  includes a step which defines an angular surface  138 . Angular surface  138  is designed to reflect the laser beam to indicate the speed of the vehicle as discussed below. The material for base plate  134  can be designed to reflect the laser beam, angular surface  138  can be painted or printed to reflect the laser beam or angular surface  138  can be provided with an appliqué for reflection of the laser beam. 
   Laser indicating system  132  comprises a printed circuit board  140 , a laser diode  144 , a rotating hub  146  and a stepped motor  148 . Printed circuit board  140  is mounted behind face plate  130 . Laser diode  144  emits a beam  152  which is directed toward angular surface  138 . Laser diode  144  is disposed within rotating hub  146  which is mounted to stepped motor  148  which is mounted to circuit board  140 . Rotating hub  146  is mounted above face plate  130  with stepped motor  148  being mounted behind face plate  130  to circuit board  140 . 
   Beam  152  emitted by laser diode  144  is directed towards angular surface  138  and is reflected toward the driver by angular surface  138 . Beam  152  can be a generally linear or rectangular beam or beam  152  can be any shape which can indicate the speed of the vehicle. Beam  152  is directed towards angular surface  138  and angular surface  138  is disposed radially inward from the plurality of indicators  136  or the plurality of indicators  136  can be located on angular surface  138 . Stepped motor  148  electrically communicates with a vehicle. Stepped motor  148  rotates rotating hub  146  which moves beam  152  circumferentially around face plate  130  in order to place beam  152  adjacent the specific indicator  136  for indicating the current speed of the vehicle.