Abstract:
An apparatus includes a surface; the surface has a conductive layer within a thickness of the surface. A trench is formed in the conductive layer to define a touch area, the touch area is isolated from the rest of the conductive layer. A conductive pickup is mounted on a back side of the surface over the touch area and the conductive pickup is electrically connected to a capacitive touch controller, such that when a user touches the touch area on a front side of the conductive the touch controller responds to the user&#39;s touch.

Description:
RELATED APPLICATIONS 
       [0001]    This patent application claims priority from U.S. Provisional Patent Application Ser. No. 61/395,898 filed on May 18, 2010 titled “APPARATUSES AND METHODS FOR COMBINING MIRRORS WITH ELECTRONICS” and is hereby incorporated by reference into the present application. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The invention relates generally to capacitive touch controllers, and more specifically to combining capacitive touch controllers with a conductive surface. 
         [0004]    2. Art Background 
         [0005]    Capacitive touch controllers are typically used with non conductive surfaces such as plastic, wood, ceramic, glass, etc. When capacitive touch controllers are used with conductive surfaces or surfaces that have a conductive layer, noise is capacitively coupled into the touch controller resulting in spurious false signals. This can present a problem. 
         [0006]    Mirrors are used in various rooms of a dwelling such as in any room of a home, or in a hotel room, such as a bath room, living room, bed room, etc. Often, when a mirror is used indoors, light is needed to adequately illuminate the person using the mirror. Systems embedded into a mirror to provide light generally require controls so that a user can adjust the light. Mechanical switches are often a source of failure resulting in maintenance and expense to repair. This can present a problem. 
         [0007]    Various integrations of a mirror surface and electronic devices are used for medicine cabinets and wall mounted mirrors. Such an integration of components provides a person with various functionality such as a local light source that illuminates the person while the person is using the mirror, television programming on an information display incorporated into the mirror, etc. These systems require controls. Mechanical controls are often associated with moving parts that can fail. This can present a problem. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The invention may best be understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the invention. The invention is illustrated by way of example in the embodiments and is not limited in the figures of the accompanying drawings, in which like references indicate similar elements. 
           [0009]      FIG. 1A  illustrates a block diagram of a capacitive touch controller, according to one embodiment of the invention. 
           [0010]      FIG. 1B  illustrates another block diagram of a capacitive touch controller, according to embodiments of the invention. 
           [0011]      FIG. 1C  illustrates a cross-section view of a capacitive touch controller and a conductive surface, according to embodiments of the invention. 
           [0012]      FIG. 2  illustrates partitioning a touch area, according to embodiments of the invention. 
           [0013]      FIG. 3  illustrates partitioning a conductive area, according to embodiments of the invention. 
           [0014]      FIG. 4  illustrates multiple touch areas, according to embodiments of the invention. 
           [0015]      FIG. 5  illustrates a capacitive touch control with a mirror, according to embodiments of the invention. 
       
    
    
     DETAILED DESCRIPTION  
       [0016]    In the following detailed description of embodiments of the invention, reference is made to the accompanying drawings in which like references indicate similar elements, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those of skill in the art to practice the invention. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure the understanding of this description. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the invention is defined only by the appended claims. 
         [0017]    Apparatuses and methods are described that permit a capacitive touch controller to work with a conductive surface. In various embodiments, a capacitive touch controller is used with a conductive surface to control lighting and other devices. Elements in figures are shown either larger or smaller than actual size to facilitate clarity of illustration. No absolute or relative size information should be inferred therefrom. 
         [0018]      FIG. 1A  illustrates a block diagram of a system, generally at  100 , according to embodiments of the invention. With reference to  FIG. 1A , in various embodiments, a capacitive touch control system  102  includes a micro-controller unit  104 , a capacitive touch controller  106 , and number of touch pads designated by  108   1 ,  108   2  up to  108   n . Alternatively, in some configurations, the micro-controller unit  104  is combined together with the capacitive touch controller  106  into a single chip implementation. Embodiments of the invention are not limited thereby. Touch pads  108   1 ,  108   2  up to  108   n  are configured on a circuit board as conductive areas, typically copper covered areas of the circuit board. The maximum number of touch pads used is limited by the capacitive touch controller of choice and the number of functions that a designer chooses to control with the system. 
         [0019]    A surface is indicated at  110 . The surface  110  has a conductive layer located within a thickness of the surface. The conductive layer is partitioned into a number of touch areas such as an  112   1 , an  112   2  up to an  112   n . The touch pads  108   1 ,  108   2  up to  108   n  and the touch areas  112   1 ,  112   2  up to an  112   n  are sized similarly and aligned so that touch areas over positioned over touch pads. 
         [0020]    The micro-controller unit  104  is connected so that the capacitive touch control system can provide a signal that is used to control a desired device, such as a device  114 . For example, a signal from the micro-controller unit  104  can be sent to a switch and the switch can turn on and off the desired device  114 . Any desired device can be configured to be operated by the capacitive touch control system such as lights, information displays such as monitors, televisions, defoggers, etc. 
         [0021]      FIG. 1B  illustrates another block diagram of a capacitive touch controller, generally at  130 , according to embodiments of the invention. With reference to  FIG. 1B , the capacitive touch control system  102  is shown with the addition of an optical isolation unit  132 . In some embodiments, it is desirable to isolate the capacitive touch control system  102  from the device that is being controlled. If the device that is being controlled has a high level of electrical noise, placing an optical-to-electrical link in between the micro-controller unit  104  and the external device isolates the capacitive touch control system  102  from the high noise level of the external device. 
         [0022]    An example of a device that produces a high noise level when connected to a capacitive touch controller is a ballast control device  134  and dimmer for fluorescent lights  140 . Signals from the micro-controller unit  104  are converted to optical signals and then back to electrical signals at the optical isolation unit  132 . Thereby providing electrical isolation from the ballast control device  134 . 
         [0023]      FIG. 1C  illustrates a cross-sectional view of a capacitive touch controller and a conductive surface, generally at  160 , according to embodiments of the invention. With reference to  FIG. 1C , a surface  162  extends into the plane of the figure and has two-dimensional extent similar to that illustrated with a surface  201  in  FIG. 2 . With reference back to  FIG. 1C , the surface  162  has a conductive layer  170 . A conductive layer such as  170  acts as an antenna picking up unwanted electromagnetic energy (noise) that adversely affects the capacitive touch control system by capacitively coupling this noise into the system, which can then appear as a false touch action, i.e., a false signal. The noise problem increases as the area of the conductive surface increases. As the thickness of the surface  162  increases, a signal resulting from a user touching a touch area decreases, making it hard to detect a user&#39;s touch from the background noise presented by the environment. Background noise is reduced by placing a trench  164   a  around a touch pad area  166  in the conductive layer  170  and as such partitions the conductive layer  170  into the touch pad area. Removal of the conductive layer is implied by use of the term trench. The user touches a region of the surface designated at  168  to trigger the touch pad control. 
         [0024]    A capacitive touch control system  188  has a touch pad  190 . The capacitive touch control system  188  is positioned against the surface  162  so that the touch pad area  166  is over the touch pad  190 . In one embodiment, an optional source of light  184  emits light which is directed via  186  into a layer  182  located on a back side of the surface  162 . In various embodiments,  186  is an array of optical fibers that directs light into the layer  182 . An adhesive layer  180  attaches the optional layer  182  to the back side of the surface  162 . Those of skill in the art will note that additional adhesive layers are used as needed to fix the capacitive touch control system  188  onto the back side of the surface  162 . Light emitted from the layer  182  provides a source of backlight to the trenches and moats visible on a front side of the surface  162  when the surface  162  is made of a transparent or translucent material such as glass or plastic. 
         [0025]    When a user touches the surface  162  in the region of  168 , with his or her finger, the capacitive touch control system  102  outputs a signal that is used to control a device. 
         [0026]    As described in this description of embodiments, a conductive layer can be made of any material that conducts electricity such the reflective coating on a mirror, a metal layer, etc. The surfaces described herein, such as  162 , are any surface that does not conduct electricity such as glass, wood, plastic, etc. Thus, embodiments of the invention are suited for use on mirrors. Some non-limiting examples of mirrors include mirrors both large and small and deployed in a variety of places such as in bathrooms, living rooms, kitchens, hotel rooms, etc. Mirrors containing embodiments of the invention can be used as standalone units or incorporated into a device such as a medicine cabinet. Thus, the examples given are non-limiting. Embodiments of the invention are not limited to use in any particular device but can be deployed in a variety of devices. 
         [0027]      FIG. 2  illustrates partitioning a touch area, generally at  200 , according to embodiments of the invention. With reference to  FIG. 2 , in one embodiment  FIG. 2  represents a top view of  FIG. 1C  as indicated by reference numeral “A.” A conductive layer on a surface  201  is partitioned. Before partitioning, the surface  201  had a conductive layer disposed thereon or within a thickness of the surface.  FIG. 2  illustrates the result of partitioning. The conductive layer has been partitioned into a touch area  206  and a first remainder area  202 , separated by a trench  204 . Alternatively, the process can be thought of as isolating the touch area  206  from the rest of the conductive layer  202 . The trench  204  is used to isolate the touch area  206  from the conductive layer  202 . The trench has a width as indicated at  208  and represents removal of the conductive layer from the area indicated by the trench. 
         [0028]      FIG. 3  illustrates partitioning a conductive area, generally at  300 , according to embodiments of the invention. With reference to  FIG. 3 , the surface  201  is partitioned again resulting in a second remainder area  302  and an island  308 . The trench  204  creates a touch area  206  as described in  FIG. 2 . A moat  304  creates an island  308  and the resulting second remainder area  302  of the original conductive layer. 
         [0029]    The moat  304  has a thickness  306 . Addition of the moat  304  to create the island  308  reduces the electrical noise picked up by the capacitive touch system that would be used with the touch area  206  in  FIG. 3 . In some system configurations it is advantageous to ground the remainder areas or islands such as  202  ( FIG. 2 ),  302  ( FIG. 3 ),  308  ( FIG. 3 ) or  408  ( FIG. 4 ). Bringing the remainder areas to earth ground reduces the magnitude of electrical noise that couples into the capacitive touch control system. 
         [0030]      FIG. 4  illustrates multiple touch areas, generally at  400 , according to embodiments of the invention. With reference to  FIG. 4 , a surface  401  has a conductive layer that has been separated into several areas. A first touch area  410  is separated by a trench  411  from an island  408 . The trench  411  has a thickness indicated at  412 . A second touch area  420  is separated by a trench  421  from the island  408 . The trench  421  has a thickness indicated at  422 . A third touch area  430  is separated from the island  408  by a trench  431 . The trench  431  has a thickness indicated at  432 . The remaining portion of the conductive layer after partitioning is indicated at  402 . A moat  404  having a thickness indicated by  406  separates the island  408  from the larger conductive layer. An optional connection to ground is indicated at  440  between the remainder of the conductive layer  402  and earth ground. Another optional connection to ground can be made between the island  408  and earth ground. 
         [0031]    Ground connection with a reflective layer of a mirror is accomplished by removing any protective non-conducting paint that might be applied over the conductive layer from an area approximately the size of a quarter. In one embodiment, one end of a strip of conductive copper tape is applied to this area and then the other end of the conductive copper tape is connected to any part of the mirror structure that is connected to earth ground for example a frame, cabinet, etc. It may be desirable to have more than one ground connection between the reflective area of the mirror and earth ground. 
         [0032]    Various embodiments are used to incorporate capacitive touch control systems with surfaces having conductive layers that are large, measuring several square feet of square yards in area. Additionally, the surfaces that the capacitive touch controller is used with can be thick. For example, embodiments of the system are implemented for use with a surface made of mirror glass in excess of 6 millimeters in thickness. 
         [0033]    For a given capacitive touch control unit, as the distance between the touch pad and the touch area increases (due to increasing surface thickness) the touch pad and touch areas should be increased in order to provide more signal to the capacitive touch controller. Increasing the sensitivity of a touch controller can also be done to sense the smaller signal resulting from the increased distance between the touch pad and the touch area. 
         [0034]    The multiple touch areas  410 ,  420 , and  430  are intended to permit generation of separate control signals. Therefore, it is desirable to minimize cross-talk between touch pads. The trenches  411 ,  421 , and  431  provide capacitive isolation between touch pads. As the trench widths  412 ,  422 , and  432  are increased, the capacitive cross-talk between touch pads is decreased. Isolation from electrical background noise that is picked up by the remainder of the conductive layer  402  is minimized by increasing the moat thickness  406 . 
         [0035]    One non-limiting example of an implementation of a capacitive touch control system with a mirror having a thickness of approximately six millimeters and an area of approximately two square meters, resulted in an island having a width of approximately 4 inches, a height of approximately 1.25 inches, a moat having a width of approximately 0.40 inch. Touch pads and touch areas of approximately 0.6 inch by 0.6 inch with trench and moat widths of 0.040 inch. Center to center spacing between touch pads of 1.3 inch. Various capacitive touch controllers can be used such as devices available from ATLab, Silicon Labs, Microchip, Cypress, ST Microelectronics, Freescale Semiconductor, Atmel, Analog Devices, and others. 
         [0036]      FIG. 5  illustrates a capacitive touch control with a mirror, generally at  500 , according to embodiments of the invention. With reference to  FIG. 5 , multiple touch areas  400  (in one embodiment, as shown in  FIG. 4 ) are used in conjunction with a capacitive touch control system incorporated with a mirror  502 . The touch control is configured to control backlight illumination within the mirror via light emitted from backlights  504  and  506 . 
         [0037]    Capacitive touch controls provide inputs to an electronic control board, attached to the backside of the mirror (described above in conjunction with the preceding figures) that perform various functionality. In various embodiments, the electronic controls can include a processor that receives inputs from the touch controls and executes predefined functions in response thereto. A user touches one of the control areas to create a change in the capacitive circuit attached to the mirror coating on the back side of the mirror. The user&#39;s touch and corresponding change in the capacitive circuit attached thereto trigger a change in an electronic component associated with the touch control. A non-limiting list of electronic components that can be controlled by the touch controls are: lighting on/off, light intensity, light intensity as modulated by the presence of a user sensed by a proximity sensor, user controllable functions associated with a media display device, such but not limited to volume, channels, power, etc. 
         [0038]    In various embodiments, energy saving features are employed through an interactive use model with a user. For example, on power up, the built-in control brings up a light level to a value, which is less that full power, such as for example 30%, then after a period of time the control will increase light output to higher power until full power is reached. If a user lowers the power level of the light then the control will maintain that power level until the user changes it again. 
         [0039]    A night light feature provides a low power state to save energy. The night light feature can set the amplitude of light output to as low as 1% of maximum. Night light amplitude is also user definable using the controls on the capacitive touch pad. 
         [0040]    If a user brings the amplitude below 30%, for example to 5% the light output stays at 5%. A proximity sensor senses whether a user is within a predefined distance of the mirror and lowers the light if a user is not within the predefined range. 
         [0041]    Percentages and values listed herein are given for illustration only. Embodiments of the invention are not limited thereby. 
         [0042]    For purposes of discussing and understanding the embodiments of the invention, it is to be understood that various terms are used by those knowledgeable in the art to describe techniques and approaches. Furthermore, in the description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one of ordinary skill in the art that the present invention may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present invention. These embodiments are described in sufficient detail to enable those of ordinary skill in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical, and other changes may be made without departing from the scope of the present invention. 
         [0043]    As used in this description, “one embodiment” or “an embodiment” or similar phrases means that the feature(s) being described are included in at least one embodiment of the invention. References to “one embodiment” in this description do not necessarily refer to the same embodiment; however, neither are such embodiments mutually exclusive. Nor does “one embodiment” imply that there is but a single embodiment of the invention. For example, a feature, structure, act, etc. described in “one embodiment” may also be included in other embodiments. Thus, the invention may include a variety of combinations and/or integrations of the embodiments described herein. 
         [0044]    While the invention has been described in terms of several embodiments, those of skill in the art will recognize that the invention is not limited to the embodiments described. The description is thus to be regarded as illustrative instead of limiting.