Abstract:
An ejector handle mounted to an electronic circuit card provides leverage to assist in engaging and disengaging the electronic circuit card from engagement with an electronic shelf. The ejector handle transmits light, such as by using light pipes, from an end of the handle adjacent to the faceplate of the electronic circuit card to a distal end of the handle where the transmitted light exits for viewing by maintenance personnel. A visual indicator assembly on the electronic circuit card supplies the sources of light that are coupled to and transmitted through the ejector handle. Indicia on the surface of the ejector handle identifies the corresponding function of the lights.

Description:
BACKGROUND 
     This invention relates generally to electronic circuit cards (boards) and more specifically relates to visual indicators that provide information concerning the status of conditions or functions of an associated electronic circuit card. 
     Electronic circuit cards are generally well known. One common type of electronic circuit card is designed to be inserted into an electronic rack or shelf and has rear edge connectors that engage corresponding connectors on a backplane. Because of the force that must be applied to the electronic circuit card to disengage its rear edge connectors, various types of ejector handles mounted to a front panel of the electronic circuit card have been utilized to provide additional mechanical leverage. A substantial number of electronic circuit cards are typically contained in a shelf. An enclosure may contain a plurality of shelves thereby holding a large number of electronic circuit cards. 
     An important design consideration of electronic circuit cards is the ability to convey to maintenance personnel information concerning the status of conditions and/or functions of the electronic circuit card. This information is typically conveyed by the use of visual indicators, such as light emitting diodes (LEDs), mounted to the front panel of the electronic circuit card. Some cards may also utilize front panel mounted connectors used to connect the card via a multiple wire cable to other electronics. The front panel may also contain a plurality of switches, jacks, and openings to permit adjustments and selections to be made by maintenance personnel. The various status indicators and controls must be highly visible and unambiguous in order to reduce the chances of craft errors, such as removing the wrong card, from adversely affecting system reliability. 
     The front panels of some electronic circuit cards are becoming congested. The use of mezzanine boards, also known daughter boards, places additional demands on the need for the faceplate space of the electronic circuit cards. The increasing congestion places constraints on the number of visual indicators that can be accommodated and on locations where the visual indicators can be placed. An additional consideration associated with the visual indicators is the text or symbol that serves as a label and is normally screen printed on the front panel adjacent each indicator. The label may occupy more area on the front panel than the indicator itself. Various identifying labels containing information about manufacturers, model numbers, serial numbers, and barcodes further congest the front panel. With increasingly less space available on the front panel of electronic circuit cards, there exists a need for better utilization of space used for visual indicators. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to satisfy the need for better utilization of space for visual indicators associated with electronic circuit cards. 
     In accordance with an embodiment of the present invention, an ejector handle adjacent to the front of the faceplate mounted to an electronic circuit card transmits light received at an end of the handle adjacent the faceplate to a distal end of the handle that is disposed to be seen by maintenance personnel with the electronic circuit card in operation. The light may be transmitted by a first light pipe that terminates at the distal end of the handle at a lens or frosted end of the light pipe to enhance the visibility and/or dispersion of transmitted light A second light pipe aligned to transmit light to the first light pipe couples light emitted from a light source on the printed circuit card. A plurality of first and second light pipes permits the ejector handle to carry a plurality of visual indicators. Labels associated with the visual indicators can be placed on a surface of the ejector handle in proximity to the visual indicator. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of an electronic circuit card with a faceplate and ejector handles in accordance with an embodiment of the present invention. 
     FIG. 2 is a cross-sectional view taken about line  2 — 2  in FIG.  1 . 
     FIG. 3 is a perspective view of an embodiment of an ejector handle in accordance with the present invention. 
    
    
     DESCRIPTION OF EMBODIMENTS 
     Referring to FIG. 1, an embodiment of the present invention includes an assembly  10  consisting of electronic circuit card  12 , a faceplate  14  and ejector handles  16  and  18 . A plurality of electronic components  20  that may include both active and passive devices are mounted to the electronic circuit card  12 . The rear of the card contains a plurality of edge mounted connectors  22  disposed to engage corresponding connectors on a backplane (not shown) when the assembly  10  is mounted in an electronic shelf, typically with a plurality of other such assemblies. The electronic circuit card  12  and the faceplate  14  support visual indicator assemblies  24  and  26  that transmit visual indication lights to ejector handles  16  and  18 , respectively. 
     As shown in FIG. 1, ejector handle  16  is in a position that it will normally assume when the assembly  10  is seated within an electronic shelf with the edge connectors  22  engaging the corresponding connectors on the backplane. The ejector handle  16  includes a handle portion  17 . In this position the distal end  28  of the ejector handle  16  is disposed to point substantially away from the faceplate  14  so that the distal end  28  will easily be observed by maintenance personnel looking at the front of faceplate  14 . The ejector handle  18  is shown in the position that it will normally assume when the assembly  10  is not seated within an electronic shelf, i.e. when the edge connectors  22  are not engaging the corresponding connectors on the backplane. In this position its distal end  30  does not point directly away from the front of faceplate  14 . As will he appreciated by those skilled in the art, handles  16  and  18  will both normally be in the same position, i.e. either pointing substantially away from the faceplate  14  when the assembly  10  is seated and assembly IO is operational, or pointing at an angle with regard to the faceplate  14  when the assembly IO is not seated. The ejector handles  16  and  18  pivot about pins (not shown) disposed in apertures  32  and  34 , respectively, with the pins supported by mounting brackets  36  and  38 , respectively. The apertures  32  and  34  are examples of means associated with the body of the ejector handle for facilitating movement of the body relative to the electronic shelf. The mounting brackets are attached to the faceplate  14 . Teeth  40  and  42  on handles  16  and  18 , respectively, are disposed to engage a fixed member associated with the electronic shelf to provide maintenance personnel with leverage to move the assembly  10  left as shown in FIG. 1 as the ejector handles are rotated from the seated position as represented by handle  16  to the not seated position as represented by handle  18 . The teeth are examples of means for engaging the electronic shelf in order to generate leverage from the electronic circuit card relative to the shelf. Of course, other mechanical designs can be used to provide such engagement and leverage. 
     Referring to FIG. 2, visual indicator assembly  24  includes a plurality of light sources  44  such as LEDs mounted to electronic circuit card  12 . Each light source is coupled to a corresponding light pipe  46  with a distal end  48  that preferably terminates at the front surface of faceplate  14  after passing through an opening  50  in the faceplate. Advantageously, light pipe  46  includes a 90 degree bend, permitting the use of standard high intensity surface mount LEDs. Light pipe  52  in ejector handle  16  preferably has one end  54  in optical alignment with distal end  48  of light pipe  46 . The other end  56  of light pipe  52  terminates at distal end  28  of the ejector handle  16  and preferably includes a treatment to maximize the visibility of light exiting from light pipe  52 . The treatment may include frosting or beveling of the end  56  of the light pipe, or may comprise the use of a lens or dispersion enhancing texture associated with end  56 . The air gap, if any, between end  54  of light pipe  52  and end  48  of light pipe  46  should be minimized in order to maximize the amount of light teaching end  56 . Optical elements, such as collomination lenses can be applied to light pipe ends  48  and  54  to enhance the light coupling efficiency. As best seen in FIG. 2 the illustrative embodiment includes three additional light pipes in the ejector handle  16  parallel to light pipe  52 . The visual indicator assembly  24  will preferably contain the same number of light pipes as disposed in ejector handle  16  with a distal end of each of the light pipes in assembly  24  aligning with a corresponding end of a light pipe in ejector handle  16 . Preferably, a separate light source is connected to each of the light pipes in assembly  24 . Each light source may emit a different color of light or may be controlled by circuitry on card  12  to selectively emit different colored light depending on the status of the condition or function to be represented. Further, the light sources can be pulsed ON and OFF at different rates to provide indications of different conditions. The light pipes on ejector handle  16  and  18  may each represent a visual indication of a condition or status of a different function. The materials for light pipes  44 ,  52  and the three additional light pipes parallel to them, as well as the material comprising the handle body  16  are selected to insure isolation between the plurality of optical paths. 
     The light pipes may each comprise a separate conventional light pipe. However, the light pipes, especially those in the ejector handle  16 , may comprise other means for transmitting light through the handle. For example, the handle may be made of a material suited for the transmission of light with separate light pipes being defined by boundary surfaces that reflect or redirect light. The boundary surfaces can be reflective such as a silvered surface or could comprise the use of other materials with a different index of a fraction so that light inside the defined light pipe will tend to stay within the light pipe. 
     FIG. 3 illustrates an alternate embodiment of an ejector handle  60  with a distal end  62  and an end  64 , which in the seated or operational position, will be substantially adjacent to the front surface of the faceplate of an associated electronic circuit card in an electronic shelf. The ejector handle  60  contains a plurality of parallel, coplanar, light pipes  66  disposed in corresponding channels  68  along and external surface  70  of the ejector handle. Thus, the light pipes  66  are easily installed in channels  68  in handle  60 . It will be noted that the light pipes in ejector handles  16  and  18  are interior of the external surfaces and thus require holes or passages to be fabricated as part of the ejector handles. Labels designating the functions associated with the light pipes can be disposed on the ejector handles. For example as shown in FIG. 3, a label can be printed adjacent each light pipe in an area such as  72  along the length of the handle, or can be printed or embossed at an area  74  on the distal end  62  of the ejector handle. Such labels can also be affixed to similar locations for ejector handles  16  and  18 . 
     If light pipes  66  are designed to provide some degree of internal dispersion, taper, or side emission, the status indication not only appears as a bright spot at the distal end of handle  60 , but also as an illuminated stripe along its entire length. If a label with a transparent or translucent background is located directly over such a side emitting light pipe, the label will appear backlit, providing an excellent user interface. 
     In accordance with embodiments of the present invention, more of the front surface of faceplate  14  is available for other uses since visual status indicators and associated labels are located on the ejector handles themselves. 
     Although embodiments of the present invention have been described and shown in the drawings, various modifications can be made to the illustrative embodiments. For example, the visual indicator assembly could comprise LEDs mounted to a small board extending from printed circuit card  12  so that each of the LEDs was aligned with and close to the respective ends of light pipes in the injector handle when the injector handle is in the seated position. Various types of light sources can be utilized such as incandescent bulbs, lasers and various types of solid-state light emitting devices. The ejector handles can comprise different shapes and can provide leverage without being pivotally mounted, e.g. appropriately designed ejector handles could slide or hinge. These alternative designs are described to illustrate a few of the various modifications that can be made. The scope of the invention is defined by the claims that follow.