Patent Application
20070018965
This invention relates generally to touch sensor and touch control technologies, and more particularly, to illuminated keyboard assemblies applicable to touch control technologies.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
As illustrated in
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.
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.
As illustrated in
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.
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.
