Abstract:
An illuminated button for use with a shuttle knob mechanism. The mechanism includes an actuator disposed through a resilient member that is captured by a first retainer and supported by a second retainer and a light guide. The light guide is disposed through the light pipe and functions to illuminate on the face of the button.

Description:
This application claims the benefit of provisional application No. 60/192,717, filed Mar. 28, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to mechanisms for activating electrical switches. More specifically, the present invention concerns a button assembly with an integrated light pipe for use with a shuttle knob mechanism. 
     2. Description of the Background Art 
     Assemblies for selectively actuating switch closures in response to a manual movement of a member, such as a button assembly, have seen increasing utility and are often found in devices such as computer interfaces, joysticks, automotive mirror controls and the like. Illuminated button assemblies, and applications in, for example, telecommunication devices, televisions and associated peripherals (i.e., control boxes, remotes, video players and the like). These illuminated button assemblies allow a user to select responses to menu prompts in a quick and efficient manner, using a minimal user interface. However, illuminated button assemblies require careful design and meticulous construction in order to enable the user of the illuminated button assembly to be able to view the button assembly. Often, misalignment between the button and the illumination source prevents the button assembly from becoming properly illuminated. Additionally, some illuminated button assemblies overheat due to the illumination source being integrated directly into the button assembly. This causes the illumination source to burn out prematurely and thus require replacement. 
     Other prior art switch activating mechanisms include captive, touch-type activators, optical interrupted beam type actuators and piezo-electric-type activators. As a general rule, these latter types of devices have limited applicability and are appropriate for only certain specialized applications. 
     Therefore, there is a need in the art for an illuminated button assembly providing good illumination characteristics and simplicity of assembly, in relation to other button assemblies. Furthermore, such illuminated button assemblies should be able to be used without thermal radiation to the tactile portion of the button assembly. 
     SUMMARY OF THE INVENTION 
     The disadvantages associated with the prior art are overcome by the present invention of a button spring assembly with an integrated light pipe. Specifically, the button with the integrated light pipe of the present invention comprises a light pipe having an alignment key, a switch activator and at least one graphic designator molded within the light pipe itself. The light pipe fits into a button spring support assembly which is comprised of a spring molded in between and to a bottom support ring and button cap on top. The light pipe slides in through the bottom support ring into the top button cap until it reaches an alignment key located on the cap. The alignment key of the light pipe helps to align the light pipe to its correct orientation with respect to the cap and the rest of the assembly. The top button cap is a circular cap on which is molded two alignment tabs for aligning the light pipe. The bottom support ring consists of a ring with an aperture and a set of alignment notches disposed about the outside perimeter of the support ring. At least one alignment pin is also disposed in the bottom face of the lower support ring. The alignment notches and alignment pin help to align the assembly when it is being installed on a PC board in a shuttle knob mechanism. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The teachings of the present invention can readily be understood by considering the following detailed description in conjunction with the accompanying drawings, in which: 
     FIGS. 1A and 1B depict a perspective view of an embodiment of the light pipe of the present invention in different orientations showing the top and bottom of the light pipe; 
     FIGS. 2A and 2B depict a perspective view of an embodiment of the button spring support assembly of the present invention in different orientations showing the support assembly from a top and bottom view; and 
     FIG. 3 depicts a perspective view of the method in which the light pipe is combined with the button spring support assembly of the present invention. 
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. 
    
    
     DETAILED DESCRIPTION 
     Specifically, FIG. 1 depicts a light pipe assembly  100  having an actuator  102  formed at the bottom of the light pipe assembly  100 . The upper light pipe assembly  104  includes a set of graphic designators  106  which are disposed through the entire length of the light pipe assembly  100  down through the actuator portion  102  of the light pipe. The upper light pipe assembly also contains an alignment key  108  which is disposed around the outer perimeter of the upper portion  104  of the light pipe assembly  100 . The light pipe assembly  100  is preferably fabricated from a moldable plastic, glass or any translucent/transparent material, or in the alternative, may simply be apertures projecting through the light pipe assembly  100  from the top portion through to the actuator portion  102 . 
     FIGS. 2A and 2B depict a button spring support structure  200  for use with the light pipe assembly  100 . The button spring support assembly is comprised of an upper button cap  202  that contains a set of alignment tabs  212  disposed about the inside of the cap, as seen in FIG. 2B, a spring assembly  204  and a lower support ring  206 . The cylindrical button spring  204  is molded between upper button support cap  202  and lower support ring  206  and is preferably fabricated from a moldable plastic, such as an elastomer. The fabrication material for the spring  204  is the same as the rest of the support unit  200  and is selected to preferably provide a resilient means to the spring  204 . The lower support ring  206  is of a similar diameter to upper button cap  202  and supports upper button cap  202  and spring  204 . Lower support ring  206  incorporates two alignment notches  208  and an alignment pin  210  to ensure proper placement of the entire assembly on a PC board. Specifically, the notches  208  align with tabs on the inside of the shuttle knob (not shown) while the pin  210  is inserted into an aperture formed in the P.C. board (not shown). Of course, the pin  210  and the notches  208  may be readily replaced by other types of locating structures commonly known in the art. 
     FIG. 3 depicts a perspective view of the light pipe assembly combined with the button spring support assembly of the present invention. As can be seen, the light pipe assembly  100  of FIG. 1 fits snuggly in the button spring support structure  200  of FIG.  2 . In practice, the light pipe assembly  100  is aligned and inserted into the button spring support structure  200  by first placing the top light pipe portion  106  of the light pipe assembly  100  into the aperture of the lower support ring  206 , the light pipe assembly  100  is then rotated so as to align alignment key  108  with corresponding alignment ribs  212  that are disposed in the upper button cap  202 . Once aligned, the alignment key  108  slides adjacent to the alignment ribs  212  where the alignment ribs  212  prevent further rotation of the light pipe assembly  100 . The light pipe is then sonically welded into the cap  202 . 
     A completed assembly per FIG. 3 is ready to be installed between a printed circuit board assembly and a shuttle knob mechanism (not shown). The alignment notches are designed to fit into a shuttle knob mechanism or bezel assembly (not shown) and to prevent rotation of the bezel or shuttle knob about the light pipe assembly  100  and button spring support assembly  200 . 
     As the embodiments that incorporate the teachings of the present invention have been shown and described in detail, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings without departing from the spirit of the invention.