Abstract:
An illuminated pointer includes an outer pointer that surrounds an inner pointer. The outer pointer extends from a base and is generally elliptical. The inner pointer extends from the base into the void of the outer pointer. The illuminated pointer utilizes a single light source for illuminating both the outer and inner pointer. The inner pointer provides easier reading of a dual scale gauge such as with a speedometer having both English and Metric speed scales.

Description:
This application claims priority to U.S. Provisional Application Ser. No. 60/523,329 which was filed on Nov. 19, 2003. 

   BACKGROUND OF THE INVENTION 
   This invention generally relates to an illuminated pointer for an instrument panel. More particularly, this invention relates to an illuminated pointer that provides independent pointing on two scales. 
   Instrument panels for a vehicle include several gauges for displaying and conveying information to a driver. The instrument panel typically includes a speedometer along with other gauges such as a tachometer, battery level indicator, and oil pressure gauge. Typically a pointer is mounted to move relative to the fixed graphical image on each gauge. 
   The pointer is typically one of two basic types, either a non-active pointer or an active pointer. A non-active pointer is illuminated by a light source mounted to a circuit board positioned behind a light transparent output shaft. Light is reflected into the pointer and scattered to illuminate the pointer. An active pointer includes a light source secured to the moving pointer. 
   In each configuration, the pointer includes a body portion that extends from a first end coupled to a motor and a second end that moves relative to the graphical image. The body portion is typically painted to block and direct light to provide consistent illumination throughout visible portions of the pointer. In many instances, the speedometer will include both an English scale in miles per hour (MPH) and a Metric scale in Kilometers per hour (Km/h). The English scale is usually placed radially about an axis of rotation of the pointer. The Metric scale is then placed in a smaller radial arrangement within the English scale. A single pointer is utilized to read each scale. Such single pointers typically extend to the larger English scale and block the corresponding reading on the Metric scale. The blocked and covered reading is the reading that relates to the actual reading provided by the pointer. Accordingly, such pointers make it difficult to accurately read the Metric or secondary scale. 
   It is known to provide a pointer with a hollowed out center section. The center section provides for viewing of the smaller Metric scale, however, the accuracy is limited due to the absence of a true pointer as is provided for the larger English or primary scale. Further, the hollowed out center section of the pointer creates challenges to illuminating the tip of the pointer by conventional methods. 
   Accordingly, it is desirable to develop and design an illuminated pointer that provides accurate visual indication on two scales simultaneously. 
   SUMMARY OF THE INVENTION 
   An example illuminated pointer includes a first pointer for indicating on a primary scale and a second pointer for indicating on a secondary scale. The pointer includes three light reflecting surfaces for illuminating the outer pointer and the inner pointer. 
   The illuminated pointer includes a first pointer and a second pointer. The first pointer points to a numerical value on a primary scale and the second pointer points to a numerical value on a secondary scale. The first pointer is generally elliptically shaped with an opening. The opening provides for clear viewing of the secondary scale. The second pointer extends partially into the opening to point to a numeric value on the secondary scale. The combination of the opening and the second pointer provides an accurate and readable visual reference of vehicle speed as indicated on the secondary scale. 
   The pointer assembly is illuminated in both the first pointer and the second pointer. The first pointer and the second pointer are substantially evenly illuminated utilizing a single light source. Light from the light source propagates into the pointer assembly and is scattered on a bottom surface. The base includes three inclined reflective surfaces, each of which reflects a portion of light emitted from the light source along and through first and second legs of the first pointer and through the second pointer. The inclined reflective surfaces include angles relative to an axis that decreases the amount of light that passes through the reflective surfaces. This results in an increase in light that is reflected within the pointer assembly, resulting in a desirable increase in overall brightness of the pointer assembly. 
   Accordingly, the pointer assembly of this invention provides an illuminated pointer that provides an accurate visual indication on two scales simultaneously. 
   These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plane view of a speedometer including two scales and an illuminated pointer according to this invention. 
       FIG. 2  is a perspective view of an illuminated pointer according to this invention. 
       FIG. 3  is a cross-sectional view of an illuminated pointer with a light source. 
       FIG. 4  is an enlarged view of the illuminated pointer including light reflecting surfaces. 
       FIG. 5  is a cross-sectional view through a section of the illuminated pointer. 
       FIG. 6  is a view of a bottom side of the illuminated pointer. 
       FIG. 7  is a perspective view of another illuminated pointer according to this invention. 
       FIG. 8  is a perspective view of still another illuminated pointer according to this invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  shows an instrument panel  10  including a speedometer  11 . The speedometer  11  includes a primary scale  12  and a secondary scale  14 . The scales are represented on a graphical display  16 . The example illustrated includes the primary scale  12  in English units indicating a speed of a vehicle in miles per hour (MPH) and the secondary scale  14  in Metric units indicating a vehicle speed in Kilometers per hour (KM/h). As appreciated the units on the primary and secondary scales  12  and  14  can be of known scale or reversed as desired for a specific application. 
   A pointer assembly  18  includes a first pointer  20  and a second pointer  22 . The first pointer  20  points to a numerical value on the primary scale  12  and the second pointer points to a numerical value on the secondary scale  14 . The first pointer  20  is a generally elliptical shape with an opening  28 . The opening  28  provides for clear viewing of the secondary scale  14 . The second pointer  22  extends partially into the opening  28  to point to a numeric value on the secondary scale  14 . The combination of the opening  28  and the second pointer  22  provides an accurate and readable visual reference of vehicle speed as indicated on the secondary scale. 
   Referring to  FIG. 2 , the pointer assembly  18  includes a base  30  that is supported atop a shaft  32 . A first leg  24  and a second leg  26  extend from the base and project radially outward. Each of the first leg  24  and the second leg  26  terminate at a tip  34 . The tip  34  provides the visual reference pointer to the numeric value reading on the graphical display  16 . The second pointer  22  also extends from the base between both the first and second legs  24 ,  26  into the opening  28 . The second pointer  22  terminates at a tip  36  disposed within the opening and along a common axis  35  with the tip  34  of the first pointer  20 . The overall length of the first pointer  20  from the base  30  to the tip  34  corresponds with the radius of the primary scale  12 . Further the length of the second pointer  22  from the base  30  to the tip  36  corresponds with the radius of the secondary scale  14 . 
   Referring to  FIG. 3 , the pointer assembly  18  is illuminated in both the first pointer  20  and the second pointer  22 . The first pointer  20  and the second pointer  22  are substantially evenly illuminated utilizing a single light source  42 . In the example embodiment the light source  42  is mounted to a printed circuit board (PCB)  40 . The shaft  32  is hollow and serves as a light guide for light emitted from the light source  42 . The base of the pointer assembly  18  includes three surfaces that provide total internal reflection. Reflected light from the light source  42  propagates into the pointer assembly  18  and is scattered on a bottom surface. The base  30  includes the light reflecting surfaces, one of which is indicated at  52 . 
   Referring to  FIG. 4 , the base  30  includes the three inclined reflective surfaces  52 ,  54  and  56 . Each of the inclined reflective surfaces  52 , 54 , and  56  reflect a portion of light emitted from the light source  42  along and through the first and second legs  24 ,  26  of the first pointer  20  and through the second pointer  24 . The length shape and angle of each inclined reflecting surface is determined to direct light along a desired path through the different portion of the pointer assembly. A worker versed in the art with the benefit of this disclosure would understand how to configure a light-reflecting surface to direct light along a desired path. 
   Further, the inclined reflective surfaces  52 ,  54 ,  56  include angles relative to the axis  64  and light emitted through the shaft  32  that decrease the portion of light that passes through the reflective surfaces. This results in an increase in light that is reflected within the pointer assembly, resulting in a desirable increase in light that is delivered to the lower scattering surface of the pointer assembly  18 . This results in an increase in overall brightness of the pointer assembly  18 . 
   Referring to  FIG. 5 , the second pointer  22  is shown in cross-section and includes a bottom surface  48  a top surface  46  and sides  50 . The cross-section is substantially rectangular with the bottom surface  48  having a width  62  that is smaller than a width  60  of the top surface  46 . The bottom surface  48  provides for scattering of light that then passes to the upper surface  46  and is visible to a vehicle operator. The change in height, and width of the surfaces of the pointer  22  provide for adjustment to illumination characteristics of the pointer assembly  18 . Such adjustments provide for the even and uniform illumination of the pointer  22 . As appreciated, although a cross-section of the second pointer  22  is shown, the cross-sections for the first and second legs  24 , 26  of the first pointer  20  are similar and may also be adjusted to provide desired illumination characteristics. 
   Referring to  FIG. 6 , the lower surface  48  of the pointer assembly  18  is covered with a reflective white layer  44 . The reflective white layer  44  is applied to the pointer assembly  18  to prevent illumination from leaking through the bottom surface  48 . Light is reflected off the reflective white layer  44  back toward the top surface  46 . The use of the reflective white layer  44  improves light efficiencies. A worker versed in the art with the benefit of this disclosure would understand that any material known in the art may be utilized for the reflective white layer  44 . 
   Referring to  FIG. 7 , another pointer assembly  70  includes the first pointer  20  and the second pointer  22 . The pointer assembly  70  includes three inclined reflective surfaces  72 , 74 , and  76  that are offset from the axis  64  and shaft  32 . The inclined reflective surfaces  72 , 74 , and  76  are positioned on a side opposite the first pointer  20  and the second pointer  22  to reflect light from a light source disposed in a non-axial position with the shaft  32 . The three inclined reflective surfaces  72 , 74 , and  76  receive and reflect light from a light source  42  that is positioned on an opposite side of the axis  64  from the first and second pointers  20 ,  22 . 
   Referring to  FIG. 8 , another pointer assembly  80  includes inclined reflective surfaces  82 , 84 , and  86  on a side of the axis  64  common to the first pointer  24  and the second pointer  22 . In the example pointer assembly  80  a light source  42  is provided on a common side of the axis  64 , and the position of the inclined reflective surfaces  82 , 84 , and  86 . As appreciated, in some application it is desirable to utilize a non-axially positioned light source and still provide substantially even illumination throughout the pointer assembly. 
   Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.