Abstract:
A touch control interface includes a panel having first and second surfaces. The first surface defines a touch interface area. The panel includes an opening extending entirely between the first and second surfaces, and the panel includes at least one touch sensitive element positioned within the touch interface area. An illumination source is positioned proximate the opening for transmitting light through said opening.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates generally to touch sensor and touch control technologies, and more particularly, to illuminated keyboard assemblies applicable to touch control technologies.  
         [0002]     Due to their convenience and reliability, touch sensitive control interfaces are increasingly being used in lieu of mechanical switches for various products and devices. Conventional touch control interfaces, or touch sensing systems are utilized in a variety of electronic applications such as, for example, appliances, industrial processes or equipment, automotive equipment, kiosks, point of sale terminals, medical equipment, mobile communications, portable electronic entertainment, hand held instrumentation or other electronic applications. The associated device may be finger operated by pressing predefined areas of the interface, and the device typically includes a controller coupled to the interface to operate mechanical and electrical elements of the device in response to user commands entered through the touch control interface.  
         [0003]     Various types of technologies are available for use in touch control interfaces, including but not limited to touch sensitive elements such as, for example, capacitive sensors and infrared detectors, and switching elements (e.g., membrane switch assemblies) responsive to touch keypads However, at least one drawback with these known touch control interfaces is the difficulty and expense associated with illuminating the predefined touch area of the interface. In at least some known touch control interfaces, particularly those interfaces utilizing switching elements, lighting is accomplished using a lighting source embedded within a keypad of the interface. In at least some other known touch control interfaces, the keys may be backlit using an illumination source positioned near, but offset with respect to the touch area of the interface.  
         [0004]     Additionally, problems exist with positioning lighting sources proximate to the touch sensors. Specifically, the lighting sources may cause signal interference with the touch sensing system when the lighting sources are positioned too close to the touch sensors. As a result, shielding of the touch sensors from the lighting source may be needed. Thus, lighting known touch control interfaces is difficult and costly, or may be inadequate for the particular application.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0005]     In one aspect, a touch control interface is provided including a panel having first and second surfaces. The first surface defines a touch interface area. The panel includes an opening extending entirely between the first and second surfaces, and the panel includes at least one touch sensitive element positioned within the touch interface area. An illumination source is positioned proximate the opening for transmitting light through said opening.  
         [0006]     Optionally, a transparent cover extends along the panel and defines a touch region overlying the touch interface area. The panel may include a circuit board having signal traces extending along the second surface of the panel. Optionally, the illumination source may include one of a light emitting diode, a light bulb, and an electroluminescent panel, and the illumination source may be substantially aligned with said opening and said touch interface area. The touch sensitive element may extends along an edge of the opening. The opening may be substantially rectangular having opposed lateral walls and opposed longitudinal walls, and the touch sensitive element may extend along the opposed longitudinal walls and one of the opposed lateral walls of the opening. Optionally, the panel may include a plurality of openings having touch sensitive elements surrounding each opening.  
         [0007]     In another aspect, a touch control interface is provided including a panel having first and second surfaces, wherein the first surface defines a touch interface area having a touch sensitive element therein. The panel includes a cut-out extending entirely between the first and second surfaces, and the touch sensitive element is positioned adjacent the cut-out. A cover overlies the panel and includes a touch region, wherein the touch region and the touch sensitive element defining a touch sensor for the touch control interface. An illumination source is positioned proximate the cut-out and illuminates the touch region through the cut-out.  
         [0008]     In a further aspect, a touch control interface system is provided including a device having a controller and a number of components operatively connected thereto, and a touch control interface communicating with the controller. The touch control interface includes an interface panel having a plurality of openings and a plurality of touch sensitive areas surrounding each opening. The interface panel also includes touch sensitive elements associated with each respective one of the touch sensitive areas. A cover overlies the panel and defining a plurality of touch regions associated with each respective one of the touch sensitive areas. An illumination source is positioned proximate the plurality of openings and illuminates the plurality of touch regions through the plurality of openings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is an exploded perspective view of a touch control interface for an electronic device and formed in accordance with an exemplary embodiment of the present invention.  
         [0010]      FIG. 2  is a perspective view of an upper surface of a component of the touch control interface shown in  FIG. 1 .  
         [0011]      FIG. 3  is a perspective view of a lower surface of the component shown in  FIG. 2 .  
         [0012]      FIG. 4  is a side cross-sectional view of the touch control interface shown in  FIG. 1  in an assembled state.  
         [0013]      FIG. 5  is an assembled view of the touch control interface and the electronic device shown in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]      FIG. 1  is an exploded perspective view of a touch control interface  10  for an electronic device or product  12 . The device  12  may be applicable to, but is not limited to applications such as appliances, industrial processes or equipment, automotive equipment, kiosks, point of sale terminals, medical equipment, mobile communications, portable electronic entertainment, hand held instrumentation or other electronic applications. More specifically, the touch control interface  10  may be utilized within electronic devices  12  utilizing a human interface such as, for example, touch control technology, padless touch sensor technology, capacitive touch sensing systems, or like systems that use signal generation and detection, as those in the art would appreciate.  
         [0015]     The touch control interface  10  includes an interface panel or circuit board  14  having a plurality of openings or cut-outs  16  which are surrounded by touch sensitive elements  18 , also referred to hereinafter as touch plates  18 . The number of openings  16  and touch sensitive elements  18  may be varied depending on the number of inputs or “keys” associated with the electronic device  12 . In one embodiment, and as illustrated in the Figures, the touch control interface  10  includes four openings  16  and four touch sensitive elements  18 . The touch control interface  10  also includes a controller  20  that is mounted to the interface panel  14  during assembly and that is operatively coupled to the touch sensitive elements  18 , as will be described below in more detail. Moreover, the controller  20  is also operatively coupled to the electronic device  12 . The elements  18 , and the controller  20  are configured to detect an actual touch, also referred to herein as a touch detection or touch result, at the associated touch sensitive elements  18 . Unlike known switching elements (e.g., membrane switch assemblies), touches are detected electronically, and actual mechanical or electrical switching of a conductive path, and associated reliability issues thereof, is avoided.  
         [0016]     The touch control interface  10  also includes a cover or dielectric element  22 . The cover  22  functions as a touch interface and includes a plurality of touch regions  24  that correspond to the touch sensitive elements  18 . Specifically, the touch regions  24  overlie the touch sensitive elements  18  and the openings  16  and provide an area for the user to interface with the touch control interface  10 . Optionally, the touch regions  24  may include indicia, such as numbers or characters, indicating the function of the particular key or input of the touch control interface  10 . In an exemplary embodiment, the cover  22  is transparent or translucent, or otherwise allows light to pass therethrough. Additionally, in an exemplary embodiment, the cover  22  may be fabricated from a dielectric material, such as for example, glass, plastic, polycarbonate, and the like, and has a thickness selected to allow the touch sensitive elements  18  to detect a “touch” by the user.  
         [0017]     The touch control interface  10  also includes an illumination source  26 . Optionally, the illumination source  26  may be an illuminating device such as, for example, a light emitting diode (LED), a light bulb, a electroluminescent panel or element, or the like. In the illustrated embodiment, the touch control interface  10  includes four illumination sources  26 , and each illumination source  26  is substantially aligned with corresponding openings  16  of the interface panel  14 . Alternatively, the illumination sources  26  may be off-set with respect to the openings  16  but nonetheless project light through the openings. Moreover, as will be described in detail below, when the touch control interface  10  is assembled, the light emitted by each illumination source  26  is directed through the openings  16  such that the touch regions  24  of the cover  22  and/or the panel  14  may be illuminated.  
         [0018]      FIGS. 2 and 3  are top and bottom perspective views of an upper surface  28  and a lower surface  30 , respectively, of the interface panel  14 . The openings  16  extend entirely through the interface panel  14  and between the upper and lower surfaces  28  and  30  such that light can be transmitted through the openings  16 .  
         [0019]     As illustrated in  FIG. 2 , the upper surface  28  of the interface panel  14  includes the touch sensitive elements  18 . The upper surface  28  is defined as the surface of the interface panel  14  oriented to interface with the user, and as such is outwardly facing when assembled with the electronic device  12  (shown in  FIG. 1 ). The upper surface  28  includes multiple touch interface areas  32 , shown in phantom in  FIG. 2 , corresponding to the touch sensitive elements  18 , openings  16  and touch regions  24  of the cover  22  (shown in  FIG. 1 ). In one embodiment, the touch areas  32  extend along the upper surface  28  in a predefined pattern. For example, the touch sensitive elements  18  may be oriented along an outer edge  34  of the openings  16  such that the touch sensitive elements  18  substantially surround the openings  16 . As such, the user may activate the touch sensitive element  18  by touching the cover  22  proximate to the opening  16  of the desired input.  
         [0020]     In one embodiment, the openings  16  have a substantially rectangular shape, and each touch sensitive element  18  surrounds a corresponding opening  16 . Optionally, the touch sensitive elements  18  extend along all four edges of the opening  16 . Alternatively, the touch sensitive elements  18  may extend along less than all four edges of the opening  16 . For example, and in an exemplary embodiment, the touch sensitive elements  18  have a generally C-shape or a U-shape and extend along three edges of the openings  16 . As such, the openings  16  may be positioned relatively closer together. In other alternative embodiments, the openings  16  have a circle or oval shape, and the touch sensitive elements  18  substantially surround the openings  16 . However, it is realized that the openings  16  and touch sensitive elements  18  may have other shapes as would be appreciated by those in the art.  
         [0021]     In an exemplary embodiment, the touch sensitive elements  18  are fabricated from a conductive material, such as for example, copper and are capacitive touch sensors such as those described in U.S. Pat. No. 5,760,715, the disclosure of which is hereby incorporated by reference in its entirety. When the touch sensor system of U.S. Pat. No. 5,760,715 is employed as the touch sensitive elements  18 , and the touch sensitive elements  18  are capacitively distributed around the openings  16 , a touch may be detected when the touch sensitive elements  18  associated with the respective touch areas  32  issue a test pulse to earth ground and detect the return of the test pulse through the human user and through the touch area  32 . In alternative embodiments, the touch sensitive elements  18  are infrared detectors, or other known tactile or touch-based sensors familiar to those in the art employing voltage sensing, current sensing and the like to detect a user activation of the touch sensitive area. In an exemplary embodiment, each touch sensitive element  18  includes a through-hole or via  36  extending through the interface panel  14  to the lower surface  30  thereof.  
         [0022]     As illustrated in  FIG. 3 , the lower surface  30  of the interface panel  14  includes a plurality of signal traces  38  extending between and electrically and mechanically coupling the touch sensitive elements  18  with the controller  20 . The lower surface  30  is generally opposed to and substantially planar with the upper surface  28 . In one embodiment, the signal traces  38  extend along the lower surface  30  in a predefined pattern. Specifically, the signal traces  38  extend from the vias  36  to the controller  20 . As such, the signal traces  38  and the vias  36  mechanically and electrically connect the controller  20  to the touch sensitive elements  18 .  
         [0023]     Moreover, the controller  20  is mechanically and electrically coupled to a plurality of contact pads  40  by corresponding contact traces  42 . The contact pads  40  are oriented to interface with other electronic components of the electronic product  12 , such as, but in no way limited to, a microprocessor for operating the electronic product  12  or a display viewable by the user.  
         [0024]      FIG. 4  is a side cross-sectional view of the touch control interface  10  mounted within the electronic device  12 , and is optionally mounted within a dedicated cavity  50  of the electronic device  12 . The cover  22  is coupled to and extends along the upper surface  28  of the interface panel  14 . Additionally, the illumination sources  26  are mounted within the cavity  50  and are generally aligned with the openings  16  extending through the interface panel  14 . In one embodiment, the illumination sources  26  are activated upon a touch to the touch region  24  of the cover  22 . In another embodiment, the illumination sources  26  are continuously illuminated, or are illuminated for a predetermined time, or in response to a predetermined event. As such, the cover  22 , and more particularly, the touch region  24  is backlit by the illumination sources  26 . Additionally, because the illumination sources  26  are positioned a distance  52  from the upper surface  28  of the interface panel  14 , the risk of interference or signal degradation of the touch sensitive elements  18  with the illumination sources  26  is reduced. As a result, a cost effective and reliable back lighting system is accomplished with the use of the touch control interface  10 .  
         [0025]      FIG. 5  is an assembled view of the touch control interface  10  and the electronic device  12 . The cover  22  and the upper surface  28  of the interface panel  14  of the touch control interface  10  are oriented within the electronic device  12  to define a touch interface. Each of the touch regions  24  of the cover  22  and the touch sensitive elements  18  of the interface panel  14  define keys or inputs for operating the electronic device  12 . In one embodiment, the electronic device  12  includes a display  54  operatively coupled to the touch control interface  10 .  
         [0026]     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.