Abstract:
A method for operating a stove including providing a plurality of burners beneath a cooktop surface and a plurality of visible-light emitters mounted under the surface for separately, variably illuminating edges of the surface adjacent to each of the burners, providing a touch-and-proximity sensor for detecting objects above the surface, illuminating at least one edge of the surface in response to the sensor detecting a pot suspended above one of the burners, and intensifying the illuminating commensurate with proximity of the pot to the one burner, as further detected by the sensor.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a non-provisional of U.S. Provisional Application No. 61/806,414, entitled USER INTERFACE FOR WHITE GOODS AND ASSOCIATED MULTI-CHANNEL PROXIMITY SENSORS, and filed on Mar. 29, 2013 by inventors Thomas Eriksson, Stefan Holmgren, Carl Richard Henriksson and Stefan Östergårde, the contents of which are hereby incorporated herein in their entirety by reference. 
     This application is a continuation-in-part of U.S. patent application Ser. No. 14/140,635 entitled LIGHT-BASED PROXIMITY DETECTION SYSTEM AND USER INTERFACE, and filed on Dec. 26, 2013 by inventors Thomas Eriksson and Stefan Holmgren, the contents of which are hereby incorporated herein in their entirety by reference. 
     U.S. patent application Ser. No. 14/140,635 is a continuation of U.S. patent application Ser. No. 13/732,456, now U.S. Pat. No. 8,643,628, entitled LIGHT-BASED PROXIMITY DETECTION SYSTEM AND USER INTERFACE, and filed on Jan. 2, 2013 by inventors Thomas Eriksson and Stefan Holmgren. 
     U.S. patent application Ser. No. 13/732,456 claims the benefit of U.S. Provisional Patent Application No. 61/713,546 entitled LIGHT-BASED PROXIMITY DETECTION SYSTEM AND USER INTERFACE, and filed on Oct. 14, 2012 by inventor Stefan Holmgren. 
     This application is a continuation-in-part of U.S. patent application Ser. No. 14/088,458 entitled LIGHT-BASED TOUCH CONTROLS ON A STEERING WHEEL AND DASHBOARD, and filed on Nov. 25, 2013 by inventors Gunnar Martin Fröjdh, Simon Fellin, Thomas Eriksson, John Karlsson, Maria Hedin and Richard Berglind, the contents of which are hereby incorporated herein in their entirety by reference. 
     U.S. patent application Ser. No. 14/088,458 claims the benefit of U.S. Provisional Application No. 61/730,139 entitled LIGHT-BASED TOUCH CONTROLS ON A STEERING WHEEL AND DASHBOARD, and filed on Nov. 27, 2012 by inventors Gunnar Martin Fröjdh, Thomas Eriksson, John Karlsson, Maria Hedin and Richard Berglind. 
     U.S. patent application Ser. No. 14/088,458 is a continuation-in-part of U.S. patent application Ser. No. 13/854,074 entitled LIGHT-BASED FINGER GESTURE USER INTERFACE, and filed on Mar. 30, 2013 by inventors Thomas Eriksson, Per Leine, Jochen Laveno Mangelsdorff, Robert Pettersson, Anders Jansson and Magnus Goertz. 
     U.S. patent application Ser. No. 13/854,074 is a continuation of U.S. patent application Ser. No. 13/424,592, now U.S. Pat. No. 8,416,217, entitled LIGHT-BASED FINGER GESTURE USER INTERFACE, and filed on Mar. 20, 2012, by inventors Thomas Eriksson, Per Leine, Jochen Laveno Mangelsdorff, Robert Pettersson, Anders Jansson and Magnus Goertz. 
     U.S. patent application Ser. No. 13/424,592 claims the benefit of U.S. Provisional Patent Application No. 61/564,868 entitled LIGHT-BASED FINGER GESTURE USER INTERFACE, and filed on Nov. 30, 2011 by inventors Thomas Eriksson, Per Leine, Jochen Laveno Mangelsdorff, Robert Pettersson and Anders Jansson. 
     U.S. patent application Ser. No. 13/424,592 is a continuation-in-part of U.S. application Ser. No. 12/760,568, entitled OPTICAL TOUCH SCREEN SYSTEMS USING WIDE LIGHT BEAMS, and filed on Apr. 15, 2010 by inventors Magnus Goertz, Thomas Eriksson and Joseph Shain. 
     U.S. patent application Ser. No. 12/760,568 claims the benefit of U.S. Provisional Patent Application No. 61/169,779, entitled OPTICAL TOUCH SCREEN, and filed on Apr. 16, 2009 by inventors Magnus Goertz, Thomas Eriksson and Joseph Shain. 
     U.S. patent application Ser. No. 12/760,568 is a continuation-in-part of U.S. application Ser. No. 12/371,609, now U.S. Pat. No. 8,339,379, entitled LIGHT-BASED TOUCH SCREEN, and filed on Feb. 15, 2009 by inventors Magnus Goertz, Thomas Eriksson and Joseph Shain. 
     U.S. patent application Ser. No. 14/088,458 is a continuation-in-part of U.S. patent application Ser. No. 13/775,269 entitled REMOVABLE PROTECTIVE COVER WITH EMBEDDED PROXIMITY SENSORS, and filed on Feb. 25, 2013 by inventors Thomas Eriksson, Stefan Holmgren, John Karlsson, Remo Behdasht, Erik Rosengren and Lars Sparf. 
     U.S. patent application Ser. No. 13/775,269 claims the benefit of U.S. Provisional Patent Application No. 61/713,546 entitled LIGHT-BASED PROXIMITY DETECTION SYSTEM AND USER INTERFACE, and filed on Oct. 14, 2012 by inventor Stefan Holmgren. 
     U.S. patent application Ser. No. 14/088,458 is a continuation-in-part of U.S. patent application Ser. No. 13/424,543 entitled OPTICAL ELEMENTS WITH ALTERNATING REFLECTIVE LENS FACETS, and filed on Mar. 20, 2012 by inventors Stefan Holmgren, Lars Sparf, Magnus Goertz, Thomas Eriksson, Joseph Shain, Anders Jansson, Niklas Kvist, Robert Pettersson and John Karlsson. 
     U.S. patent application Ser. No. 13/424,543 claims priority benefit of U.S. Provisional Patent Application No. 61/564,164, entitled OPTICAL ELEMENTS WITH ALTERNATING REFLECTIVE LENS FACETS, and filed on Nov. 28, 2011 by inventors Stefan Holmgren, Lars Sparf, Thomas Eriksson, Joseph Shain, Anders Jansson, Niklas Kvist, Robert Pettersson and John Karlsson. 
     U.S. patent application Ser. No. 13/424,543 is a continuation-in-part of PCT Application No. PCT/US11/29191 entitled LENS ARRANGEMENT FOR LIGHT-BASED TOUCH SCREEN, and filed on Mar. 21, 2011 by inventors Magnus Goertz, Thomas Eriksson, Joseph Shain, Anders Jansson, Niklas Kvist, Robert Pettersson, Lars Sparf and John Karlsson. 
     U.S. patent application Ser. No. 13/424,543 is a continuation-in-part of U.S. patent application Ser. No. 12/760,567 entitled OPTICAL TOUCH SCREEN SYSTEMS USING REFLECTED LIGHT and filed on Apr. 15, 2010. 
     PCT Application No. PCT/US11/29191 claims the benefit of U.S. Provisional Patent Application No. 61/379,012 entitled OPTICAL TOUCH SCREEN SYSTEMS USING REFLECTED LIGHT, and filed on Sep. 1, 2010 by inventors Magnus Goertz, Thomas Eriksson, Joseph Shain, Anders Jansson, Niklas Kvist and Robert Pettersson; the benefit of U.S. Provisional Patent Application No. 61/380,600 entitled OPTICAL TOUCH SCREEN SYSTEMS USING REFLECTED LIGHT, and filed on Sep. 7, 2010 by inventors Magnus Goertz, Thomas Eriksson, Joseph Shain, Anders Jansson, Niklas Kvist and Robert Pettersson; and the benefit of U.S. Provisional Patent Application No. 61/410,930 entitled OPTICAL TOUCH SCREEN SYSTEMS USING REFLECTED LIGHT, and filed on Nov. 7, 2010 by inventors Magnus Goertz, Thomas Eriksson, Joseph Shain, Anders Jansson, Niklas Kvist, Robert Pettersson and Lars Sparf. 
    
    
     FIELD OF THE INVENTION 
     The field of the present invention is light-based proximity sensors and graphical user interfaces for large electrical goods used domestically, inter alia, refrigerators, ovens and washing machines. These goods are collectively known as “white goods” because formerly these items were typically finished with white enamel. 
     BACKGROUND OF THE INVENTION 
     Conventional touch sensitive virtual buttons, i.e., buttons painted on a stationary flat surface and actuated by touch, are capacitance-based or resistance-based. Certain touch sensitive user input systems detect hovering objects as well. Examples include U.S. Publication No. 2008/0012835 A1 for HOVER AND TOUCH DETECTION FOR DIGITIZER and U.S. Publication No. 2006/0244733 A1 for TOUCH SENSITIVE DEVICE AND METHOD USING PRE-TOUCH INFORMATION. 
     Prior art hover detection systems based on reflected light determine a height of an object above a surface based on an amount of reflected light: the nearer the object—the more light is reflected onto the detector situated beneath the touch surface. Therefore, prior art systems are able to detect a hovering object over time and determine whether the object is moving closer or farther away based on relative amounts of detected light. I.e., diminishing light detection over time indicates an object moving away from the surface, and increasing light detection over time indicates an object moving toward the surface. In other words, the determined height is relative to other heights in a series of detections, but the actual height remains unknown. Indeed, different materials reflect different amounts of light, e.g., a white glove reflects more light than a black glove, and the reflective properties of a hovering object are not known by the system. Therefore, the system cannot determine the height at which the object is situated above the surface based on the amount of reflected light detected. In addition, because prior art proximity detectors require a series of detections of the object at different heights in order to rank the heights in relation to each other, a single proximity detection or a series of detections of a stationary hovering object will provide little information about the height of the object. 
     White goods typically have multiple controls that are set by a user. For example, a washing machine has controls for selecting the size of a wash load (e.g., large, medium, small), the fabric (e.g., cotton, synthetic, wool) and the temperature (e.g., hot, warm, cold). Some white goods have control panels having multiple touch-sensitive controls. In accordance with an embodiment of the present invention, white good control panels use light-based proximity sensors. 
     One problem with prior art proximity sensors is that they are prone to false touch detection, especially when the user wears shiny jewelry that reflects light onto a proximity sensor. For example, assume an array of controls placed together on a control panel, where a respective proximity sensor is situated underneath each control. When a user approaches or touches one control, a ring on the user&#39;s finger may reflect either ambient light, or light from one of the proximity sensors in the array, onto an unintended neighboring proximity sensor. This will erroneously activate the neighboring control. It would be advantageous to have a robust proximity sensor that distinguishes between intended touches and inadvertent reflections. 
     SUMMARY 
     Aspects of the present invention relate to touch sensitive surfaces used to implement tap-activated button controls, switches and slider controls for household appliances such as washing machines, refrigerators, ovens and cooktops. 
     Aspects of the present invention also relate to graphical user interfaces (GUIs) designed for white good applications. 
     Cooktops 
     There is thus provided in accordance with an embodiment of the present invention a cooktop including a surface on which to place pots containing food to be heated, a plurality of heating elements and their corresponding control circuits, situated underneath the surface, for heating the food in the pots, wherein each heating element is associated with a respective section of one or more edges of the surface, a plurality of sources of visible light arranged along the one or more edges of the surface, a proximity sensor directed at the airspace in front of the cooktop for detecting a person approaching the surface, the proximity sensor including an infrared light emitter for projecting light onto the approaching person, and an infrared light receiver adjacent to the light emitter for receiving a portion of the projected light reflected by the person, and a processor mounted beneath the surface connected to the proximity sensor and to the visible light sources, for illuminating the visible light sources when the approaching person is detected by the proximity sensor. 
     Additionally in accordance with an embodiment of the present invention, the cooktop further includes a first plurality of optical sensors arranged along the one or more edges of the surface for detecting a location of a pot positioned above one of the heating elements, and not touching the surface, wherein the processor activates certain of the visible light sources to illuminate the section of the one or more edges associated with the heating element above which the pot is positioned, and deactivates the remaining visible light sources. 
     Further in accordance with an embodiment of the present invention, the optical sensors along the edges of the cooktop identify one or more of the heating elements over which pots are placed on the surface, and the processor activates certain of the visible light sources to illuminate the sections of the one or more edges associated with those heating elements over which the pots are placed. 
     Yet further in accordance with an embodiment of the present invention, the cooktop further includes a second plurality of optical sensors situated along the one or more edges and coupled with the control circuits, whereby each of the control circuits enables its heating element to be controlled via touch gestures detected by the second plurality of optical sensors at the section of the one or more edges associated with its heating element, when that section is illuminated by the visible light sources. 
     Moreover in accordance with an embodiment of the present invention, each of the cooktop control circuits is operative to raise the temperature of its heating element, in response to detection by the second plurality of optical sensors of a glide gesture at the section of the one or more edges associated with its heating element, and the processor increases an illumination intensity of the visible light sources at that section, to indicate the rise in temperature. 
     Additionally in accordance with an embodiment of the present invention, the cooktop proximity sensor is mounted in a ventilation hood situated above the cooktop, and each of the control circuits is operative to raise the temperature of its heating element in response to a hand wave gesture in the airspace opposite the ventilation hood detected by the proximity sensor. 
     Ovens and Stoves 
     There is further provided in accordance with an embodiment of the present invention an appliance including a hollow for holding items for use with the appliance, a door for opening and closing the hollow, a transparent panel having an exposed cylindrical surface situated above the door, a display behind the panel and visible through the panel, an array of proximity sensors arranged along an edge of the panel for detecting nearby objects and for detecting user gestures performed on the exposed cylindrical surface of the panel, the proximity sensors including infrared light emitters for projecting light onto an object near the panel, and infrared light receivers adjacent to the light emitters for receiving a portion of the projected light reflected by the object, and a processor connected to the proximity sensors and to the display, for presenting information on the display in response to the user gestures detected by the proximity sensors. 
     Yet further in accordance with an embodiment of the present invention, the appliance includes an auxiliary proximity sensor mounted in the appliance and connected to the processor, for detecting a person approaching the appliance, and sources of visible light separate from the display mounted behind the panel and connected to the processor, wherein the processor is operative to illuminate the visible light sources in response to the auxiliary proximity sensor detecting the approaching person. 
     Moreover, in accordance with an embodiment of the present invention, the processor is operative to display user control icons on the panel in response to the proximity sensor array detecting an object near the panel. 
     Additionally, in accordance with an embodiment of the present invention, when the appliance is in use, the user control icons display current appliance settings. 
     Further in accordance with an embodiment of the present invention, a configurable appliance setting is presented on the display in a scroll-bar graphic, and the processor is operative to adjust the appliance setting in response to the proximity sensor array detecting a glide gesture along the scroll-bar graphic. 
     Yet further in accordance with an embodiment of the present invention, the configurable appliance setting is a temperature setting or a time setting. 
     Moreover in accordance with an embodiment of the present invention, the appliance is a member of the group consisting of a dishwasher, a refrigerator, a washing machine and an oven. 
     Appliance Control Hub 
     There is additionally provided in accordance with an embodiment of the present invention a stationary appliance including a stationary appliance housing including a socket for a mobile appliance control hub, a display panel mounted on an inner wall of the socket that is covered by the control hub in the socket and exposed when the control hub is removed from the socket, and the mobile appliance control hub, including a mobile housing configured to be inserted into the socket and removed therefrom, circuitry mounted in the mobile housing for wireless communication with the stationary appliance and with at least one additional appliance, a touchscreen mounted in the mobile housing for presenting controls for operating the stationary appliance and for operating the at least one additional appliance, and a rechargeable battery mounted in said mobile housing that is coupled to an electrical outlet provided in the socket when the hub is inserted into the socket. 
     Further in accordance with an embodiment of the present invention, the touchscreen presents icons identifying the stationary appliance and the at least one additional appliance, and presents current settings for the stationary appliance and the at least one additional appliance, in a single screen. 
     Refrigerator and Freezers 
     There is yet further provided in accordance with an embodiment of the present invention an appliance including a hollow for holding items for use with the appliance, a door for opening and closing the hollow, including a panel of electrically switchable glass having an opaque light transmission state that changes to a transparent state when voltage is applied, a proximity sensor mounted in the door for detecting hand wave gestures in the airspace opposite the door, and a processor connected to the panel and to the proximity sensor for applying a voltage to the glass to enter the transparent state in response to the proximity sensor detecting a hand wave gesture. 
     Moreover in accordance with an embodiment of the present invention, the appliance is one of a refrigerator and a freezer. 
     There is additionally provided in accordance with an embodiment of the present invention an appliance including a storage hollow for storing items for use with the appliance, a door for opening and closing the storage hollow, a handle on the front of the door forming a cavity positioned and sized to permit several fingers to grip the handle, a first proximity sensor mounted in the door for detecting an approaching user, a light source mounted in the perimeter of the handle cavity and connected to the processor, for illuminating the handle cavity, and a processor connected to the proximity sensor for illuminating the light source in response to the proximity sensor detecting the approaching user. 
     Further in accordance with an embodiment of the present invention, the appliance includes a second proximity sensor mounted in the perimeter of the handle cavity and connected to the processor, for detecting the grip, and at least one illuminable icon on an outward-facing surface of the door handle, connected to the processor, wherein the processor illuminates the icon in response to the second proximity sensor detecting the grip of the handle. 
     Yet further in accordance with an embodiment of the present invention, the processor is operative to intensify illumination of the light source illumination in response to the second proximity sensor detecting the grip of the handle. 
     Moreover in accordance with an embodiment of the present invention, the illuminated icon displays a temperature setting for the appliance. 
     Additionally in accordance with an embodiment of the present invention, the processor adjusts the temperature setting in response to the second proximity sensor detecting a directional movement of the inserted fingers within the handle cavity. 
     Further in accordance with an embodiment of the present invention, the processor is operative to release an inner vacuum in the storage hollow to facilitate opening the door, in response to the second proximity sensor detecting the grip of the handle. 
     Yet further in accordance with an embodiment of the present invention, the appliance is a member of the group consisting of a dishwasher, a refrigerator, a freezer, a washing machine and an oven. 
     Washing Machines and Clothes Dryers 
     There is moreover provided in accordance with an embodiment of the present invention an appliance including a touch sensitive panel on which a plurality of icons representing different settings are displayed, and including a demarcated area separate from the icons, and a processor connected with the panel, operative to select an icon&#39;s setting in response to detecting a finger gliding from that icon into the demarcated area. 
     Light-Based Touch Sensors 
     There is additionally provided in accordance with an embodiment of the present invention a touch sensor including a housing, a light guide mounted in the housing including an aperture through which light exits and enters the light guide, and an inner surface facing the interior of the housing, two light emitters mounted in the housing for emitting light beams into the light guide that exit the aperture at diverging angles, and a light receiver mounted in the housing for receiving reflected light beams entering the aperture at an angle of incidence different than the diverging angles. In some embodiments the diverging light beams exit the aperture at one and the same location on the aperture that the reflected light beams enter the aperture. 
     There is further provided in accordance with an embodiment of the present invention a touch sensor including a housing, a light guide mounted in the housing including an aperture through which light exits and enters the light guide, and an inner surface facing the interior of the housing, a light emitter mounted in the housing for emitting light beams into the light guide that exit the light guide at the aperture, and two light receivers mounted in the housing for receiving reflected light beams entering the light guide at the aperture at two different angles of incidence. In some embodiments the diverging light beams enter the aperture at one and the same location on the aperture that the emitted light beams exit the aperture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be more fully understood and appreciated from the following detailed description, taken in conjunction with the drawings in which: 
         FIG. 1  is a simplified illustration of a proximity sensor having one emitter-detector channel, in accordance with an embodiment of the present invention; 
         FIG. 2  is a simplified illustration of a first configuration of a proximity sensor having two emitter-detector channels, in accordance with an embodiment of the present invention; 
         FIG. 3  is a simplified illustration of a second configuration of a proximity sensor having two emitter-detector channels, in accordance with an embodiment of the present invention; 
         FIGS. 4 and 5  are simplified diagrams of a touch sensitive slider window having multiple emitter-detector channels that detect a location of a finger along the length of the window, in accordance with an embodiment of the present invention; 
         FIG. 6  is a simplified illustration of a finger placed along the touch sensitive slider window of  FIGS. 4 and 5 , in accordance with an embodiment of the present invention; 
         FIGS. 7-10  are simplified diagrams showing different views of a touch sensitive slider window having multiple emitter-detector channels that detect a location of a finger along the length of the window, in accordance with an embodiment of the present invention; 
         FIGS. 11-13  are simplified diagrams of a touch sensitive slider window having two emitter-detector channels that detect a location of a finger along the height of the window, in accordance with an embodiment of the present invention; 
         FIGS. 14-17  are simplified diagrams of a configuration of a touch sensitive window having four emitter-detector channels operative to detect a glide movement in both horizontal and vertical directions, in accordance with an embodiment of the present invention; 
         FIGS. 18 and 19  are simplified illustrations of top-shooting diodes in a configuration of a touch sensitive window having four emitter-detector channels operative to detect a glide movement in both horizontal and vertical directions, in accordance with an embodiment of the present invention; 
         FIG. 20  is a simplified illustration of a single touch sensor on a control panel, in accordance with an embodiment of the present invention; 
         FIGS. 21-23  are simplified cutaway profile views of a touch sensor in a control panel, in accordance with an embodiment of the present invention; 
         FIGS. 24-26  are simplified cross-sectional views of a touch sensor in a control panel, in accordance with an embodiment of the present invention; 
         FIGS. 27 and 28  are simplified illustrations of emitter and receiver light beams for a multi-channel touch sensor, in accordance with an embodiment of the present invention; 
         FIG. 29  is a simplified illustration of touch sensor components arranged on a substrate or printed circuit board (PCB), in accordance with an embodiment of the present invention; 
         FIG. 30  is a simplified illustration of a multi-channel touch sensor, in accordance with an embodiment of the present invention; 
         FIG. 31  is a simplified illustration of a multi-channel touch sensor, in accordance with an embodiment of the present invention; 
         FIGS. 32-34  are rotated views of a lens element used in multi-channel touch sensors and proximity sensors, in accordance with an embodiment of the present invention; 
         FIG. 35  is a simplified illustration of a cooktop with illumination, in accordance with an embodiment of the present invention; 
         FIGS. 36-41  are simplified illustrations of a user interface for a cooktop, in accordance with an embodiment of the present invention; 
         FIGS. 42 and 43  are simplified illustrations of a cooktop user interface placed in the cooktop exhaust hood, in accordance with an embodiment of the present invention; 
         FIG. 44  is a simplified illustration of an appliance, e.g., an oven, with an illuminated cylindrical control panel, in accordance with an embodiment of the present invention; 
         FIGS. 45-52  are simplified illustrations of a user interface for an oven, in accordance with an embodiment of the present invention; 
         FIGS. 53-58  are simplified illustrations of a centralized wireless hub for controlling multiple while good appliances in a home, in accordance with an embodiment of the present invention; 
         FIG. 59  is a simplified illustration of an appliance hub for controlling a plurality of kitchen appliances, in accordance with an embodiment of the present invention; 
         FIG. 60  is a simplified illustration of a control panel for a dishwasher, in accordance with an embodiment of the present invention; 
         FIG. 61  is a simplified illustration of an appliance, e.g., a refrigerator, having a hollow compartment for storing items and a door that switches from an opaque state to a transparent state for viewing the stored items through the door, in accordance with an embodiment of the present invention; 
         FIG. 62  is a simplified illustration of smart glass door for a refrigerator, in accordance with an embodiment of the present invention; 
         FIG. 63  is a simplified illustration of an appliance, e.g., a refrigerator, having a hollow compartment for storing items and an illuminable door handle, in accordance with an embodiment of the present invention; 
         FIG. 64  is a simplified illustration of a control panel and associated user interface in a door handle of a refrigerator, in accordance with an embodiment of the present invention; 
         FIGS. 65-68  are simplified illustrations of user interfaces for water and ice dispensers mounted in a refrigerator door, in accordance with an embodiment of the present invention; 
         FIG. 69  is a simplified illustration of an appliance, e.g., a washing machine or dryer, having a hollow compartment for storing items such as clothes to be washed or dried and a touch sensitive panel for providing a gesture-based user interface, in accordance with an embodiment of the present invention; 
         FIGS. 70 and 71  are simplified illustrations of a washing machine control panel, in accordance with an embodiment of the present invention; 
         FIG. 72  is a simplified illustration of an alternative control panel and associated user interface for a washing machine, in accordance with an embodiment of the present invention; and, 
         FIGS. 73-76  are simplified illustrations of additional control panels for frontloading and top loading washing machines, in accordance with embodiments of the present invention. 
     
    
    
     In this specification and in the figures, the following numbering scheme is used. Light emitting elements and emitted light beams are numbered in the range of 100-199. Light receiving elements such as PDs, and reflected light beams are numbered in the range of 200-299. Lens components, reflective and refractive elements are numbered in the range of 300-399. Fingers, styli, electronic devices and their housings are numbered in the range of 800-999. 
     The following tables catalog the numbered elements and list the figures in which each numbered element appears. 
     
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 Emitters and Emitter Beams 
               
             
          
           
               
                   
                 Element 
                 Figures 
                 Description 
               
               
                   
                   
               
               
                   
                 110 
                  1 
                 emitter beam 
               
               
                   
                 111, 112 
                 2, 30, 31 
                 emitter beam 
               
               
                   
                 113, 114 
                  3 
                 emitter beam 
               
               
                   
                 121 
                 4, 21, 23, 26, 27, 29-31 
                 emitter 
               
               
                   
                 122 
                 7-16, 18, 30 
                 emitter 
               
               
                   
                 123 
                 7, 8 
                 emitter beam 
               
               
                   
                 124 
                 12, 13 
                 emitter beam 
               
               
                   
                 126 
                 23 
                 emitter beams 
               
               
                   
                 130 
                 23, 27, 28 
                 emitter beam 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 Receivers and Receiver Beams 
               
             
          
           
               
                   
                 Element 
                 Figures 
                 Description 
               
               
                   
                   
               
               
                   
                 210 
                 1 
                 receiver beam 
               
               
                   
                 211, 212 
                 2, 30, 31 
                 receiver beam 
               
               
                   
                 213 
                 3 
                 receiver beam 
               
               
                   
                 221 
                 4-6, 21, 22, 23, 28, 29, 31 
                 receiver 
               
               
                   
                 222 
                 7-13, 21, 22, 28-31 
                 receiver 
               
               
                   
                 222.1, 222.2 
                 15, 16, 18 
                 receiver 
               
               
                   
                 222.3, 222.4 
                 16, 18 
                 receiver 
               
               
                   
                 223 
                 7, 8 
                 receiver beam 
               
               
                   
                 224, 225 
                 12, 13 
                 receiver beam 
               
               
                   
                 230, 231 
                 22, 27, 28 
                 receiver beam 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Lenses 
               
             
          
           
               
                 Element 
                 Figures 
                 Description 
               
               
                   
               
               
                 301 
                  4-10 
                 lens 
               
               
                 302 
                 11, 12 
                 lens 
               
               
                 303 
                 14 
                 lens 
               
               
                 303.1-303.3 
                 15-17 
                 lens section 
               
               
                 320 
                 17 
                 diagonal face 
               
               
                 321 
                 21-23, 25, 26, 28-34 
                 light guide 
               
               
                 322-324 
                 33, 34 
                 reflective light guide wedge 
               
               
                 330 
                 65-67 
                 light guide frame 
               
               
                 332 
                 71 
                 embossed light guide 
               
               
                 333 
                 30, 31 
                 aperture 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Miscellaneous Elements 
               
             
          
           
               
                 Element 
                 Figures 
                 Description 
               
               
                   
               
               
                 801 
                 56 
                 appliance icons 
               
               
                 802 
                 56 
                 clock 
               
               
                 803 
                 56 
                 notification 
               
               
                 805 
                 57 
                 oven icon 
               
               
                 806 
                 59 
                 battery 
               
               
                 807 
                 59 
                 communication circuitry 
               
               
                 810 
                 53, 60 
                 dishwasher 
               
               
                 811 
                 60 
                 dishwasher control panel 
               
               
                 812 
                 44 
                 appliance door 
               
               
                 820 
                 61-63 
                 refrigerator 
               
               
                 821 
                 61-63 
                 refrigerator door 
               
               
                 822 
                 63, 64 
                 handle cavity 
               
               
                 823 
                 63, 64 
                 refrigerator door handle 
               
               
                 824 
                 64 
                 temperature display 
               
               
                 825 
                 64 
                 arrow indicating movement 
               
               
                 826 
                 64 
                 glow 
               
               
                 827 
                 61 
                 voltage source 
               
               
                 828 
                 35, 61, 63 
                 proximity sensor 
               
               
                 829 
                 35, 44, 61, 63, 69 
                 processor 
               
               
                 830 
                 65, 66, 68 
                 water dispenser control panel 
               
               
                 831 
                 44, 59, 65-67 
                 display 
               
               
                 832 
                 65-67 
                 touch sensitive buttons 
               
               
                 835 
                 65 
                 water dispenser shaft illumination 
               
               
                 836 
                 68 
                 water dispenser touch icon 
               
               
                 837 
                 68 
                 water glass 
               
               
                 840 
                 70, 73, 75 
                 washing machine 
               
               
                 841 
                 70, 71 
                 washing machine control panel 
               
               
                 843 
                 71 
                 slider groove 
               
               
                 844 
                 71 
                 circular groove 
               
               
                 845 
                 71 
                 digital display 
               
               
                 846 
                 71 
                 sunken buttons 
               
               
                 847 
                 69 
                 icons 
               
               
                 848 
                 69 
                 demarcated area 
               
               
                 850, 860, 870 
                 72-76 
                 washing machine control panel 
               
               
                 851 
                 72 
                 recessed area 
               
               
                 852 
                 72 
                 dragging an icon 
               
               
                 853 
                 69 
                 washing machine 
               
               
                 861, 862 
                 74 
                 curved light guide 
               
               
                 863-866, 872 
                 74, 76 
                 washing machine controls 
               
               
                 871 
                 76 
                 array of proximity sensors 
               
               
                 900 
                 1, 2, 3, 6, 41, 72 
                 finger 
               
               
                 901 
                 2, 3 
                 finger 
               
               
                 910 
                 1-3 
                 device 
               
               
                 921 
                  4-10 
                 upper casing part 
               
               
                 922 
                  4-10 
                 lower casing part 
               
               
                 923 
                 4-10, 21-23, 25-31 
                 PCB 
               
               
                 924 
                  9, 10 
                 isolating barrier 
               
               
                 931 
                 11 
                 upper casing part 
               
               
                 932 
                 11 
                 lower casing part 
               
               
                 938 
                   43, 62-64 
                 hand 
               
               
                 939 
                 69 
                 finger 
               
               
                 941 
                 14-17 
                 upper casing part 
               
               
                 942 
                 14-17 
                 lower casing part 
               
               
                 943 
                 16 
                 PCB 
               
               
                 945 
                 17 
                 air gap 
               
               
                 950 
                 19 
                 light transmissive cover 
               
               
                 951 
                 19 
                 cross shape 
               
               
                 966 
                 20-27, 69   
                 touch panel 
               
               
                 967 
                 20, 24-27, 32 
                 touch control 
               
               
                 969 
                 35 
                 heating element control 
               
               
                 970 
                 36-41, 53   
                 induction cooktop 
               
               
                 971 
                 35-41, 56   
                 kitchen counter 
               
               
                 972, 975 
                 37-41 
                 radiance of light 
               
               
                 973 
                 38-41 
                 saucepan 
               
               
                 974 
                 40, 41 
                 pot 
               
               
                 976 
                 42, 43 
                 temperature control 
               
               
                 977 
                 42, 43 
                 range exhaust hood 
               
               
                 978 
                 35 
                 surface 
               
               
                 979 
                 35 
                 heating element 
               
               
                 980 
                 44, 45 
                 oven 
               
               
                 981 
                 45 
                 UI panel 
               
               
                 982 
                 45 
                 clock 
               
               
                 983 
                 45 
                 icons 
               
               
                 984 
                 45 
                 slider control 
               
               
                 985 
                 46-52 
                 oven touch panel 
               
               
                 986, 988 
                 49, 52 
                 tap touch controls 
               
               
                 987 
                 51 
                 slider touch control 
               
               
                 989 
                 50 
                 oven settings 
               
               
                 990 
                 53, 54, 56-59 
                 appliance control hub 
               
               
                 991, 992 
                 53-55 
                 oven 
               
               
                 993 
                 35, 63 
                 visible light source 
               
               
                 994 
                 44 
                 cylindrical panel 
               
               
                 995 
                 55 
                 hub socket 
               
               
                 996 
                 44 
                 array of proximity sensors 
               
               
                 997 
                 35 
                 section of an edge 
               
               
                   
               
             
          
         
       
     
     DETAILED DESCRIPTION 
     Aspects of the present invention relate to light-based touch controls such as virtual buttons, sliders and touch pads. Aspects of the present invention also relate to proximity sensors for hover gestures, tap gestures and sweep gestures. According to embodiments of the present invention, a light-based touch control and proximity sensor includes infra-red light-emitting diodes (LEDs) and photodiodes (PDs) situated inside a housing for an electronic device, beneath an infra-red-transmissive section of the housing. The LEDs project light substantially incident to the housing surface, through the transmissive section. When an object touches or approaches the transmissive section, it reflects the light back into the housing where it is detected by the PDs. Each detection of reflected light represents a detection channel. 
     A proximity sensor having only one LED and one PD has a single detection channel that provides one signal. In principle this signal provides binary (yes/no) information as to whether or not an object is present above the sensor. In addition, this signal provides information as to a direction of movement of the object along the proximity axis, i.e., whether the object is moving toward the sensor or away from the sensor. Thus, if the signal increases over time, the object is moving toward the sensor, whereas if the signal decreases over time, the object is moving away from the sensor. 
     Reference is made to  FIG. 1 , which is a simplified illustration of a proximity sensor having one emitter-detector channel, in accordance with an embodiment of the present invention.  FIG. 1  illustrates an embodiment whereby one LED and one PD are situated together beneath a control surface embedded in the housing. In this embodiment one detection channel is provided. 
       FIG. 1  shows a portable electronic device  910  in profile view. An emitter beam  110  is projected above the device and is reflected  210  back into the device by a finger  900  placed above the device. Thus, the light channel  110 - 210  is provided to detect a proximal finger  900 . 
     As explained hereinabove, one example of the limitations of a single channel is that it is impossible determine a distance of the object from the sensor based on the strength of the detection signal since different objects can be used that have different reflective properties. For example, a black glove near the sensor and a white glove further away from the sensor provide substantially similar levels of detection. More channels generate more information. However, an extra channel does not necessitate adding an additional LED and an additional PD. Rather, several PDs can share the light from one LED to provide multiple detection channels. Similarly, one PD can provide multiple detection channels when it is able to receive reflected light from several LEDs. 
     Reference is made to  FIG. 2 , which is a simplified illustration of a first configuration of a proximity sensor having two emitter-detector channels, in accordance with an embodiment of the present invention.  FIG. 2  illustrates two LEDs and one PD situated in a row beneath a control surface embedded in the housing. This row of two LEDs and one PD has one of the LEDs placed between the other LED and the PD. In this embodiment two detection channels are provided. With two channels positional information along one dimension can be generated by interpolation. 
       FIG. 2  shows a portable electronic device  910  in profile view and two emitter-detector light channels. Thus,  FIG. 2(A)  demonstrates a first light channel  112 - 212  that detects a near finger  901 ; and  FIG. 2(B)  demonstrates a second light channel  111 - 211  that detects a more distal finger  900 . The emitter beams  111  and  112  issue forth from the upper surface of device  910  at an angle in order that their respective reflected beams arrive at the location of the detector. The proximity detector of  FIG. 2  provides an indication of the height of the object based on which channel is detected. An interpolation of signals from the two channels will indicate a position of the object within the range of heights detected by both channels. 
     By contrast, prior art proximity detectors determine proximity based on a relative intensity of a reflected signal and require a series of detections in order to rank the different signals, as explained hereinabove. Thus, the system of  FIG. 2  addresses two shortcomings of the prior art: (1) it provides an indication of the absolute height of the object above the screen, as opposed to a relative height; and, (2) it provides this indication based on detections of a stationary object and does not require a series of detections over time. 
     Two similar detection channels are provided by two detectors and one emitter, for example by replacing the emitters of the  FIG. 2  system with detectors, and replacing the detector of the  FIG. 2  system with an emitter. In this case, beams  211  and  212  are one and the same emitter beam issued by the one emitter, and the reflected beam  111  or  112  arrives at one of the two detectors depending on the height of the finger  900  or  901  above the device  910 . 
     Reference is made to  FIG. 3 , which is a simplified illustration of a second configuration of a proximity sensor having two emitter-detector channels, in accordance with an embodiment of the present invention.  FIG. 3  shows a portable device  910  with two detection channels, but in this case the detector is situated between the two emitters and the two channels provide lateral position information. A first emitter beam  113  is projected above the device to the right of the detector, and a second emitter beam  114  is projected above the device to the left of the detector. When a finger hovers above the space between the first emitter and the detector, as illustrated by finger  900  in  FIG. 3 , it creates a first detection channel  113 - 213 . When a finger hovers above the space between the second emitter and the detector, as illustrated by finger  901  in  FIG. 3 , it creates a second detection channel  114 - 213 . An interpolation of signals from the two channels indicates a position of the object between the outermost components. As explained hereinabove, the emitters and detectors may be swapped and still provide two similar detection channels. 
     Aspects of the present invention relate to providing a thin window spanning the height or thickness of a device, such as a mobile phone. The user interacts with the phone by performing finger gestures against this window, and the proximity sensor detects the position or gesture of the finger. One application is to replace physical buttons. In the most basic case light from an LED is sent out of the device and reflected by the finger. The reflected light is detected by two PDs situated on either side of the LED and the position of the finger is interpolated from the signals. For instance such an arrangement may replace the volume buttons on a mobile phone. In principle such an arrangement may have limited proximity functionality. This conceptual model can be extended with additional components. 
     Reference is made to  FIGS. 4 and 5 , which are simplified diagrams of a touch sensitive slider window having multiple emitter-detector channels that detect a location of a finger along the length of the window, in accordance with an embodiment of the present invention. Reference is also made to  FIG. 6 , which is a simplified illustration of a finger placed along the touch sensitive slider window of  FIGS. 4 and 5 , in accordance with an embodiment of the present invention.  FIGS. 4 and 5  show front and back views of a touch sensitive slider window featuring multiple emitter-detector channels that detect a location of a finger along the length of the window.  FIGS. 4 and 5  show a sidewall of a device housing formed by an upper casing part  921  and a lower casing part  922 . A lens  301  is wedged between casing parts  921  and  922 .  FIGS. 4 and 5 , and in particular  FIG. 4 , show a PCB  923  placed inside the device housing. Light emitters  121  and light detectors  221  are mounted in an alternating row on PCB  923 . Every emitter-detector pair of neighboring elements provides a detection channel for detecting an object touching the outer side edge of the housing along the length of lens  301 , as illustrated by finger  900  in  FIG. 6 . 
     When the emitters and detectors are placed together inside the housing, light scatters inside the housing when an emitter is activated and a portion of the scattered light arrives at the detectors without being reflected by an object outside lens  301 . In order to minimize the amount of scattered light that reaches the detectors, the emitters and detectors are mounted on PCB  923  facing opposite directions. 
     Reference is made to  FIGS. 7-10 , which are simplified diagrams showing different views of a touch sensitive slider window having multiple emitter-detector channels that detect a location of a finger along the length of the window, in accordance with an embodiment of the present invention.  FIGS. 7-10  show inward-facing emitters  122  and outward-facing detectors  222 . In addition, an isolating barrier  924  is placed between the emitters and the detectors to further shield the detectors from scattered light.  FIG. 9  is an exploded view of this configuration.  FIG. 10  is a cross-section view of the same configuration. 
     Lens  301  in  FIGS. 7-10  is more complex than lens  301  in  FIGS. 4 and 5 . In  FIGS. 7-10 , in order to direct light from the inward-facing emitters out through lens  301  and back onto the outward-facing detectors, lens  301  extends over and around the emitters  122  but not the detectors  222 . Two light paths are shown in  FIGS. 7 and 8 . Emitter beam  123  is reflected twice inside lens  301  before it travels over emitter  122  and out of the device. Incoming beam  223  enters lens  301  and is reflected twice inside the lens before arriving at detector  222 . 
     Reference is made to  FIGS. 11-13 , which are simplified diagrams of a touch sensitive slider window having two emitter-detector channels that detect a location of a finger along the height of the window, in accordance with an embodiment of the present invention.  FIGS. 11-13  illustrate another configuration of a two-channel control. In this case, the control detects objects along the height of the device rather than along the length of the device as in  FIGS. 3-10 .  FIGS. 11-13  show upper and lower casing parts  931  and  932 . One emitter  122  and two receivers  222  are connected to lower casing part  932 . The detection channels are made possible by a reflecting lens  302  inserted between casing parts  931  and  932 . The light path from emitter  122  through lens  302  is illustrated in  FIG. 12  as outgoing emitter beam  124 . The light paths of the two incoming beams  224  and  225  that are directed at the two detectors  222  are also illustrated in  FIG. 12 .  FIG. 13  is a cross-section view of lens  302  and the light beam paths  124 ,  224  and  225  of  FIG. 12 . 
     With three channels, position information in two dimensions is obtained. One application is an optical joystick. A second application is a two-dimensional navigation pad. A third application is a mouse touchpad. For example, arranging three emitters at three corners of an equilateral triangle and placing a detector at the triangle&#39;s center of gravity provides three detection signals. By interpolating the signals, a two-dimensional location of the object is obtained. As a second example, begin with the two channels of  FIG. 2  to provide height information, and add one channel to provide lateral information as in  FIG. 3 . 
     Reference is made to  FIGS. 14-17 , which are simplified diagrams of a configuration of a touch sensitive window having four emitter-detector channels operative to detect a glide movement in both horizontal and vertical directions, in accordance with an embodiment of the present invention.  FIGS. 14-17  illustrate a cross-bar control for detecting up-down and right-left movements of a finger or other object. The illustrated control has four detection channels created by one central emitter  122  surrounded by four detectors  222 . 1 - 222 . 4 . An alternative configuration has one central detector surrounded by four emitters and is similar in operation to the system of  FIGS. 14-17 .  FIG. 14  shows a lens  303  situated between upper and lower casing parts  941  and  942  and the five components (emitters and receivers) mounted inside the device on a PCB ( 943  in  FIG. 16 ) connected to the lower casing part. An outer cross-shaped surface of lens  303  is flush with the outer casing. 
       FIG. 15  is a cross-sectional view of the system shown in  FIG. 14 . Lens  303  is shown divided into sections to illustrate how each section is used by a different component. Detector  222 . 1  receives light beams that enter the lens through section  303 . 1 ; emitter  122  uses section  303 . 2  to reflect light out of the lens; detector  222 . 2  receives light beams that enter the lens through section  303 . 3 . 
       FIG. 16  is an exploded view of the system shown in  FIG. 15 .  FIG. 16  shows detectors  222 . 1 - 222 . 4  and emitter  122 ; PCB  943 ; upper and lower casing parts  941  and  942 ; and lens  303  divided into upper section  303 . 1 , middle section  303 . 2  and lower section  303 . 3 . 
       FIG. 17  is a slightly rotated side view of the system of  FIG. 16 .  FIG. 17  illustrates how middle section  303 . 2  of the lens is used by detectors  222 . 2  and  222 . 4  in addition to emitter  122 . An air gap  945  behind lens  303  is also shown. The purpose of air gap  945  is to make the diagonal face  320  of lens  303  internally reflective. 
     Reference is made to  FIGS. 18 and 19 , which are simplified illustrations of top-shooting diodes in a configuration of a touch sensitive window having four emitter-detector channels operative to detect a glide movement in both horizontal and vertical directions, in accordance with an embodiment of the present invention.  FIGS. 18 and 19  illustrate a mouse pad or other two-dimensional control. This configuration places the emitters and detectors directly beneath the control surface.  FIG. 18  shows four receivers  222 . 1 - 222 . 4  surrounding an emitter  122  to provide four channels, substantially similar to those described hereinabove with reference to  FIGS. 14-17 . In  FIG. 19  an infrared light transmissive cover  950  with a cross shape  951  etched thereon is placed above the emitters and receivers. The cross shape indicates navigational paths to the user. 
     A system with four channels also provides information in three dimensions regarding a proximal object. For example, begin with the two channels of  FIG. 2  to provide height information. Add one channel to provide lateral information as in  FIG. 3 . Add one more channel to provide information in a second lateral dimension, also as in  FIG. 3 . 
       FIGS. 20-29  show a touch sensitive control having two detection channels. This control is typically used for tap-activation. The two detection channels detect reflected light from different directions, with a small area of overlap between the channels. When a user touches the control both channels are activated. This two-channel proximity sensor is able to distinguish between light reflected by a touch and light reflected from a distance, because light reflected from a distance is only detected by one of the two channels. 
     Reference is made to  FIG. 20 , which is a simplified illustration of a single touch sensor on a control panel, in accordance with an embodiment of the present invention.  FIG. 20  shows a top view of a portion of touch panel  966  having touch control  967  at its center. 
     Reference is made to  FIGS. 21-23 , which are simplified cutaway profile views of a touch sensor in a control panel, in accordance with an embodiment of the present invention.  FIG. 21  shows a first side view of touch panel  966  and PCB  923 . One light emitter  121 , two light detectors  221  and  222 , and light guide element  321 , are mounted on PCB  923  beneath touch panel  966 . An upper surface of light guide  321  is exposed at control  967 , not shown in  FIG. 21 . The current disclosure uses an embodiment of one light emitter and two light detectors. However other configurations, such as (a) one light detector and two light emitters, or (b) more than two detection channels, are also within the scope of the present invention. 
       FIG. 22  shows a second side view of touch panel  966  and PCB  923 . The viewpoints in  FIGS. 21 and 22  are from opposite edges of touch panel  966 . From the viewpoint of  FIG. 22  two light detectors  221  and  222  and light guide element  321 , are visible; light emitter  121  of  FIG. 21  is blocked from view in  FIG. 22  by light guide element  321 . From the viewpoint of  FIG. 22  two diagonal reflective facets are visible on the underside of light guide  321 . These direct divergent incoming beams  230  and  231  onto light detectors  221  and  222 , respectively. Thus, when light is reflected onto touch control  967  from a distance, e.g., by a shiny object such as a user&#39;s jewelry, only one of the detectors will detect the light. At the very least, there will be a significant difference in the amount of light detected at the two detectors. This difference indicates a false detection. In other words, the system detects a touch only when both detectors  221  and  222  detect similar amounts of reflected light. This occurs when the user&#39;s finger touches, or is very close to, touch control  967  and reflects light in many directions inside the light guide. 
       FIG. 23  shows a third side view of touch panel  966  and PCB  923 . From the viewpoint of  FIG. 23  light emitter  121 , one light detector  221  and light guide element  321  are visible; the second light detector  222  of  FIGS. 21 and 22  is blocked from view in  FIG. 23  by light guide element  321 . From the viewpoint of  FIG. 23  a diagonal reflective facet is visible on the underside of light guide  321  that directs light beam  130  from emitter  121  out above touch control  967 . Light beam  130  is projected at an angle that is divergent from the incoming angles of reflected beams  230  and  231 . In  FIG. 23 , light beam  130  is projected at an angle above touch control  967 , not at 90° to the touch panel  966 . This further reduces the likelihood that a distant reflective object will reflect beam  130  back onto touch control  967  in a manner that the reflected beam will be equally detected at both detectors  230  and  231 . Thus, touch detection is characterized by equal detections of reflected emitter beam  130  at both detectors  221  and  222 , and occurs only when the user&#39;s finger touches, or is very close to, touch control  967 . 
     Reference is made to  FIGS. 24-26 , which are simplified cross-sectional views of a touch sensor in a control panel, in accordance with an embodiment of the present invention.  FIG. 24  shows the touch panel of  FIG. 20  with cross sections A-A and B-B. Cross section A-A is shown in  FIG. 25 , and cross section B-B is shown in  FIG. 26 . Both  FIGS. 25 and 26  illustrate how an upper surface of light guide  321  is exposed at touch control  967 . 
     Reference is made to  FIGS. 27 and 28 , which are simplified illustrations of emitter and receiver light beams for a multi-channel touch sensor, in accordance with an embodiment of the present invention. The two detection channels of this proximity sensor are shown in  FIGS. 27  and  28  by emitter beam  130  and two detector channels  230  and  231 . The term “detector channel” refers to a detectable reflected beam.  FIG. 27  shows emitter beam  130  and two detector channels  230  and  231  above touch control  967 . In  FIG. 28 , touch panel  966  has been removed exposing light guide  321  emitter  121  and detectors  221  and  222  on PCB  923 . 
     Reference is made to  FIG. 29 , which is a simplified illustration of touch sensor components arranged on a substrate or printed circuit board (PCB), in accordance with an embodiment of the present invention.  FIG. 29  shows light guide  321  emitter  121  and detectors  221  and  222  on PCB  923 . Emitter beam  130  and detector channels  230  and  231  diverge to a lesser degree in  FIGS. 27 and 28  than those illustrated in  FIGS. 22 and 23 . 
     Reference is made to  FIG. 30 , which is a simplified illustration of a multi-channel touch sensor, in accordance with an embodiment of the present invention. Shown in  FIG. 30  is light guide  321  surrounded on three sides by emitters  121  and  122 , and receiver  222 . An aperture  333  at the center of light guide  321  is the exposed portion of the touch sensor when the sensor is mounted in a device. Light guide  321  is configured so that light from each of the emitters exits through aperture  333  at a different angle. Thus, light beam  111  from emitter  121  exits aperture  333  at a first angle, and light beam  112  from emitter  122  exits aperture  333  at a second angle, divergent from the first angle. Light guide  321  is also configured so that light directed to receiver  222  enters aperture  333  at a third angle, different than the angles that beams  111  and  112  exit aperture  333 . Thus, light beam  211  enters aperture  333  at a third angle. All of the components are mounted on PCB  923 . In some embodiments, none of the angles are 90° with respect to the aperture. 
     Reference is made to  FIG. 31 , which is a simplified illustration of a multi-channel touch sensor, in accordance with an embodiment of the present invention. The touch sensor of  FIG. 31  is similar to that of  FIG. 30 , except that in  FIG. 30  the two detection channels are formed by one emitter and two receivers. Shown in  FIG. 31  is light guide  321  surrounded on three sides by receivers  221  and  222 , and emitter  121 . In this case the three divergent light beams entering and exiting aperture  333  are emitter beam  111  and receiver beams  211  and  212 . 
     Reference is made to  FIGS. 32-34 , which are rotated views of a lens element used in multi-channel touch sensors and proximity sensors, in accordance with an embodiment of the present invention. 
       FIGS. 32-34  are three-dimensional views of light guide element  321  alone.  FIG. 32  shows a view of light guide element  321  from the top, showing the surface exposed through control  967 .  FIG. 33  shows a view of light guide element  321  from below. In this view, three reflective wedges  322 ,  323  and  324  are shown. Light enters each wedge and is reflected by the wedge&#39;s diagonal facet as illustrated by beams  130 ,  230  and  231  in  FIGS. 22, 23, 27 and 28 . When mounted on PCB  923 , wedge  324  is situated opposite light emitter  121  to reflect and project emitter beam  130  in  FIGS. 23, 27 and 28 ; and wedges  322  and  323  are situated opposite detectors  221  and  222 , respectively, to create detection channels  230  and  231  in  FIGS. 21, 27 and 28 . In  FIG. 34 , light guide element  321  has been turned upside down, showing reflective wedges  322 - 324  prominently. 
     White Goods User Interfaces (UIs) 
     Aspects of the present invention relate to user interfaces (UI) for household appliances. This section describes user interfaces for stoves, refrigerators, ovens and washing machines. 
     I. Cooktop UI 
     Reference is made to  FIG. 35 , which is a simplified illustration of a cooktop with illumination, in accordance with an embodiment of the present invention. Shown in  FIG. 35  is a surface  978  on which to place pots containing food to be heated. The cooktop is mounted in counter  971 . A plurality of heating elements  979  and their corresponding control circuits  969  are situated underneath surface  978 . The heating elements are used to heat the food in the pots.  FIG. 35  shows that each heating element  979  is associated with two respective sections  997  of one or more edges of surface  978 . Light sources  993  are situated underneath surface  978  along its edges. Proximity sensor  828  faces the airspace in front of the cooktop. When a person approaching the cooktop is detected by proximity sensor  828 , an indication of this detection is transmitted to processor  829  which, in response thereto, activates light sources  993  creating a visible glow along the edges of surface  978 . 
     Reference is made to  FIGS. 36-41 , which are simplified illustrations of a user interface for a cooktop, in accordance with an embodiment of the present invention.  FIG. 36  shows an induction cooktop  970  having one or more electromagnets sealed beneath a heat-resisting glass-ceramic sheet. Cooktop  970  is embedded in kitchen counter  971 . When the cooktop is not in use it is muted, as all indications and markings disappear. As explained in detail hereinbelow, this is a subtle cooktop UI that senses and reacts to user needs, contextually. 
     The cooktop ceramic sheet has arrays of lenses along each of its edges. These lenses are coupled to visible-light emitting diodes to create a steady radiance of light or glow along the cooktop edges that signals the state of the cooktop to the user. In addition, the lenses along the forward-facing edge of the cooktop are also coupled to near-infrared emitters and detectors to provide proximity detection of an approaching user and of user gestures. Thus when a user approaches the cooktop, the cooktop emits a visible glow along its edges indicating that it has “woken up” and is waiting for user input. Such a visible glow  972  along the forward-facing edge of cooktop  970  is shown in  FIG. 37 . 
     Additional proximity sensors are placed beneath each of the cooktop burners to detect a pot or pan being lowered over the burner. Alternatively, light beams are projected from the edges of the cooktop across the cooktop burners to detect a pot or pan being lowered over the burner and thereby blocking the light beams that traverse the burner. When pots and pans are held over the cooking surface, a visible glow along the cooktop edges guides the user as he places the pot or pan onto the cooktop, as shown in  FIGS. 38 and 39 .  FIG. 38  shows saucepan  973  is hovering above cooktop surface  970 . Visible glow  972  appears along the edge of cooktop  970 . Alternatively, and as shown in  FIG. 39 , only a portion of the cooktop edge corresponding to the burner beneath the hovering saucepan is illuminated to guide the user as he sets the saucepan down.  FIG. 39  shows how, once saucepan  973  is set down on a cooktop burner, a segmented interaction area lights up  972  along the borders of the cooktop, corresponding to the burner beneath the saucepan. This lit-up segment is an input control for configuring the heating element beneath the saucepan. In its lit-up state the segment is ready for receiving user input. The user does not need to separately turn on the cooktop controls as is typically required in prior art cooktops. In accordance with embodiments of the present invention, detection of the saucepan places the control into an active mode ready to receive user input.  FIG. 40  shows that several interaction areas are indicated by illuminated borders depending on active cooking zones. Thus, in  FIG. 40  illuminations  972  and  975  indicate active areas on cooktop  970  at which saucepan  973  and pot  974  have been placed. 
     The user adjusts the heat on an active burner by gliding his finger along the burner&#39;s corresponding illuminated border segment.  FIG. 41  shows a user finger  900  gliding from left to right along illuminated segment  975  to increase the heat under pot  974 . The light intensity of the illuminated segment increases as the temperature setting increases. This provides intuitive feedback to the user. 
     Reference is made to  FIGS. 42 and 43 , which are simplified illustrations of a cooktop user interface placed in the cooktop exhaust hood, in accordance with an embodiment of the present invention. In  FIG. 42  temperature control  976  is realized as a proximity sensor strip placed along a surface of exhaust hood  977  above cooktop  970 .  FIG. 43  shows that a user can adjust the temperature setting by waving his hand  938  along the temperature control strip  976  without touching the strip. An array of proximity sensors in the strip detects the position of the user&#39;s hand when it hovers at a distance of a few centimeters away from the strip. Thus, no direct touch is needed, and this keeps the surfaces and hands clean. 
     II. Oven and Stove UI 
     This section describes three appliance UI control panels. The present description mentions ovens as an example appliance into which the UI panels are incorporated, but other appliances are also within the scope of the present invention. Reference is made to  FIG. 44 , which is a simplified illustration of an appliance, e.g., an oven, with an illuminated cylindrical control panel, in accordance with an embodiment of the present invention. Shown in  FIG. 44  is oven  980  having a hollow compartment for storing food items to be cooked, and oven door  812  for opening and closing this compartment. Just above door  812  is a control panel featuring display  831  mounted behind transparent cylindrical panel  994 . An array of proximity sensors  996  is mounted above panel  994  for detecting nearby objects and for detecting user gestures performed on the exposed cylindrical surface of panel  994 . Processor  829  receives outputs from proximity sensors  996 , which indicate user gestures, and presents information on display  831  in response to the user gestures. 
     Reference is made to  FIGS. 45-52 , which are simplified illustrations of a user interface for an oven, in accordance with an embodiment of the present invention.  FIG. 45  shows an oven  980  having a first UI panel  981  above the over door. The UI panel has two, touch-sensitive sections separated by digital clock  982 . To the right of clock  982  are touch-sensitive static icons  983  for selecting oven element configuration, e.g., roast/bake/grill. To the left of clock  982  is slider groove  984  for adjusting values, e.g., oven temperature. The user glides his finger along groove  984  to raise or reduce the oven temperature, or to set the time. 
     This first oven UI panel can be realized in several ways. In some embodiments, proximity sensors are placed underneath icons  983  and slider control  984 . In other embodiments, a row of proximity sensors is situated along the upper or lower edge of UI panel  981  that detect a finger inserted onto the panel. In other embodiments, emitters along an edge of control panel  981  send light beams across control panel  981  to respective detectors along the opposite edge of control panel  981 . An inserted finger touching a control blocks one or more emitter beams from reaching corresponding one or more detectors. In some embodiments where detection is based on the absence of expected light, the emitters are arranged as a one-dimensional array along the top of control panel  981  and the detectors are arranged as a one-dimensional array along the bottom of control panel  981 . This provides detection in only one dimension, namely, along the length of the control panel  981 . As such, the controls are distributed along the length of control panel  981 . 
     A second oven UI panel is illustrated in  FIG. 46 , which shows a convex, curved control panel  985  above the over door. This convex panel is transparent and cylindrical. Beneath the panel, illuminated controls appear as described below. In  FIG. 46 , a clock is displayed on panel  985 . An array of proximity sensors is situated along the upper edge of this panel and aimed along the panel&#39;s curved surface to detect hand gestures performed on the panel. 
     As in the first oven UI panel, when the UI is not in use the panel is clean and muted.  FIG. 47  shows this state in which panel  985  is dark except for a digital clock displayed at its center. When a user approaches the oven, panel  985  is illuminated with a radiant glow as illustrated in  FIG. 48 . The approaching user is detected by forward-facing proximity sensors above, near, or behind, panel  985 . When a user&#39;s hand nears panel  985 , as detected by an array of proximity sensors along the panel&#39;s front edge, user control icons  986  appear on panel  985 , as shown in  FIG. 49 . When the oven is in use, the display provides an overview of current oven settings  989  and also allows quick access to adjust any setting directly, as shown in  FIG. 50 . 
     Both sweep gestures and tap gestures are enabled on panel  985 . The user taps on one of icons  986  of  FIG. 49  or oven settings  989  of  FIG. 50  to open a control for configuring the parameter associated with the selected icon or setting. Parameters such as oven temperature and setting the time are adjusted using a graphic slider bar  987  that the user manipulates by sweeping his finger along the slider graphic. Slider bar  987  is shown in  FIG. 51 . Other parameters are configured using button controls  988 , as shown in  FIG. 52 . 
     Reference is made to  FIGS. 53-58 , which are simplified illustrations of a centralized wireless hub for controlling multiple white good appliances in a home, in accordance with an embodiment of the present invention. A third oven UI is shown in  FIG. 53 .  FIG. 53  shows a central control hub  990  for controlling multiple kitchen appliances, such as ovens  991  and  992 , cooktop  970  and dishwasher  810 . Hub  990  can be inserted into a socket  995  (shown in  FIG. 55 ) above oven  991 , or removed from socket  995  and placed on a kitchen counter. By enclosing light-based touch sensors in an airtight sealed housing that includes infrared transmissible portions, hub  990  can be made waterproof.  FIG. 54  shows hub  990  in socket  995 ;  FIG. 55  shows socket  995  without hub  990 ; and  FIG. 56  shows hub  990  on kitchen counter  971 .  FIG. 56  shows hub  990  displaying an array of appliance icons  801  monitored by hub  990  (fridge, oven, cooktop, fan, dishwasher), clock  802  and appliance notification  803  informing the user that the dishwasher will be done in 5 minutes. 
       FIG. 57  shows that the oven appliance is selected on the hub screen, by a tap on oven icon  805 . This selection opens the screen shown in  FIG. 58  showing detailed settings and status of the oven appliance. 
     Reference is made to  FIG. 59 , which is a simplified illustration of an appliance hub for controlling a plurality of kitchen appliances, in accordance with an embodiment of the present invention. As shown in  FIGS. 54 and 55 , the appliance control hub is seamlessly inserted into a socket in a built-in kitchen appliance, e.g., oven  991 , and removed therefrom. Thus, one of the appliances controlled by the hub is the built-in appliance housing the hub&#39;s socket. Shown in  FIG. 59  is appliance control hub  990  having touchscreen display  831 , for presenting controls for operating the plurality of appliances. Hub  990  communicates wirelessly with the appliances it controls via wireless communication circuitry  807 . Rechargeable battery  806  powers the hub and is charged when coupled to an electrical outlet provided in the built-in kitchen appliance socket. 
     III. Dishwasher UI 
     Reference is made to  FIG. 60 , which is a simplified illustration of a control panel for a dishwasher, in accordance with an embodiment of the present invention.  FIG. 60  shows a dishwasher  810  equipped with a touch sensitive control panel  811  utilizing proximity sensors across the top edge of the dishwasher door. This creates a smooth and easily cleaned control surface, and enables both slide gesture and touch button functionality. In some embodiments, visible-spectrum light emitters are used to provide glow indication of an active interaction area on panel  811 . 
     IV. Refrigerator and Freezer UI 
     Reference is made to  FIG. 61 , which is a simplified illustration of an appliance, e.g., a refrigerator, having a hollow compartment for storing items and a door that switches from an opaque state to a transparent state for viewing the stored items through the door, in accordance with an embodiment of the present invention. Shown in  FIG. 61  is refrigerator  820  having a smart glass door  821 . Smart glass is electrically switchable glass which changes light transmission properties when voltage is applied.  FIG. 61  shows processor  829  connected to proximity sensor  828  and to voltage source  827 . Proximity sensor  828  faces the airspace in front of refrigerator  820 . When a wave gesture performed in front of the refrigerator is detected by proximity sensor  828 , an indication of this detection is transmitted to processor  829  which, in response thereto, activates voltage source  827  switching glass door  821  from an opaque state to a transparent state. 
     Reference is made to  FIG. 62 , which is a simplified illustration of a smart glass door for a refrigerator, in accordance with an embodiment of the present invention.  FIG. 62  shows a refrigerator  820  having a smart glass door  821 . The door is equipped with proximity sensors for detecting a hand-wave gesture in front of the refrigerator door. In response to this gesture, the glass door changes from opaque to transparent, providing a view of the refrigerator contents without opening the door. This feature saves energy, by avoiding unnecessary openings and reduces the time the door is kept open by a user. Thus,  FIG. 62  shows (A) glass door  821  in an opaque state and hand  938  placed near door  821 ; (B) a wave gesture by hand  938  in front of door  821  detected by proximity sensors in door  821  activates a circuit that applies voltage to glass  821  that switches the glass from opaque to transparent; and (C) the glass is fully transparent. 
     Reference is made to  FIG. 63 , which is a simplified illustration of an appliance, e.g., a refrigerator, having a hollow compartment for storing items and an illuminable door handle, in accordance with an embodiment of the present invention. Shown in  FIG. 63  is refrigerator  820  having door  821  and door handle  823 .  FIG. 63  shows processor  829  connected to proximity sensor  828  and to visible light sources  993 . Proximity sensor  828  faces the airspace in front of door  821  near handle  823 . When hand  938  approaches handle  823  it is detected by proximity sensor  828 . An indication of this detection is transmitted to processor  829  which, in response thereto, activates light sources  993  illuminating the cavity behind handle  823 , i.e., cavity  822 . 
     Reference is made to  FIG. 64 , which is a simplified illustration of a control panel and associated user interface in a door handle of a refrigerator, in accordance with an embodiment of the present invention.  FIG. 64  shows a user interface for a refrigerator door handle  823 . Proximity sensors on the door detect an approaching user, and additional proximity sensors on the inside of door handle  823 , i.e., in cavity  822  formed between the handle and the door, detect when a user wraps his hand  938  around handle  823 . Visible-spectrum light emitters are provided in the door or handle to illuminate cavity  822 . (A) shows the handle before a user has approached the door. No icons are displayed on the outer surface of handle  823 , and the visible-spectrum light emitters are turned off. (B) shows that when proximity sensors in the door detect an approaching user, the visible-spectrum light emitters are turned on and generate a glow  826  in handle cavity  822 . (C) shows that when the user wraps his hand  938  around door handle  823  this is detected by the proximity sensors that project light into cavity  822 . In response, three events occur: (i) the glow  826  in handle cavity  822  is intensified; (ii) the refrigerator temperature  824  is displayed on the outer surface of door handle  823  by an embedded display; and (iii) the refrigerator releases its inner vacuum in order to facilitate opening the refrigerator door. (D) shows that the user can adjust the refrigerator temperature by sliding his hand  938  up or down inside cavity  822 . In (D) arrow  825  indicates that the user slid his hand  938  downward in cavity  822 , and as a result, the displayed refrigerator temperature  824  was lowered from −19° in (C) to −22° 
     V. Water and Ice Dispenser UI 
     Reference is made to  FIGS. 65-68 , which are simplified illustrations of user interfaces for water and ice dispensers mounted in a refrigerator door, in accordance with an embodiment of the present invention.  FIG. 65  shows a water and ice dispenser. Water and ice dispensers are often included in high-end refrigerators. The water and ice dispenser has control panel  830  that includes an embedded display  831  and touch-sensitive buttons  832 . Control panel  830  is surrounded by a light guide frame  330  that is coupled with arrays of light emitters and light receivers inside the dispenser housing that project light beams across the control panel to enable touch detection at any location within frame  330 . In addition, frame  330  is also coupled to light emitters and detectors that serve as proximity sensors for sensing an approaching user. Thus frame  330  projects light beams across panel  830  for touch detection, and also projects light beams outward, perpendicular to panel  330 , for proximity detection. 
     When the proximity detectors sense an approaching user, the dispenser lights up, as illustrated in  FIG. 65(B) , where display  831  and dispenser shaft  835  are illuminated. Before an approaching user is detected, the dispenser display  831  is muted, and the dispenser shaft lights are turned off, as shown in  FIG. 65(A) . 
       FIG. 66  shows an alternative water and ice dispenser control panel  830  with a larger display screen  831 .  FIG. 67  shows another alternative water and ice dispenser control panel  830  whose entire control panel is display screen  831 . In  FIG. 60 , touch-sensitive buttons  832  are graphic icons rendered by display screen  831 . Reference is made to  FIG. 68  showing two views of yet another alternative water and ice dispenser control panel  830 . In  FIG. 68 , the touch-sensitive buttons are illuminated when activated, as illustrated by button  836  which is muted in  FIG. 68(A)  but illuminated in  FIG. 68(B)  as glass  837  is filled with water. 
     VI. Washing Machine and Clothes Dryer UI 
     Reference is made to  FIG. 69 , which is a simplified illustration of an appliance, e.g., a washing machine or dryer, having a hollow compartment for storing items such as clothes to be washed or dried and a touch sensitive panel for providing a gesture-based user interface, in accordance with an embodiment of the present invention. Shown in  FIG. 69  is washing machine  853  having touch sensitive panel  966 . Touch panel  966  presents icons  847  representing various wash settings, e.g., temperature and spin speed. Apart from icons  847 , panel  966  also has a demarcated area  848 . When a user performs a gesture of dragging finger  939  from one of the icons into demarcated area  848 , a signal indicating the icon and the gesture are communicated to processor  829 , which selects the corresponding wash setting. 
     Reference is made to  FIGS. 70 and 71 , which are simplified illustrations of a washing machine control panel, in accordance with an embodiment of the present invention.  FIG. 70  shows a frontloading washing machine  840  with control panel  841 . An enlarged view of control panel  841  is shown in  FIG. 71 . In  FIG. 71  control panel  841  is surrounded by four raised, unconnected borders  332 , embossed in the washing machine housing. These raised borders are transparent to infrared light; they are light guides that direct light over and across panel  841  to enable touch detection on the panel. Light emitters and receivers are coupled to these light guides inside the washing machine housing. 
     Controls  843 ,  844  and  846  are debossed in panel  841 :  846  are sunken buttons,  843  is a sunken slider groove and  844  is a sunken circular groove surrounding a small digital display  845 . When a user actuates any of these controls, the actuation is detected by the light emitter-detector array coupled to raised borders  332 ; the sunken controls  846 ,  843  and  844  are formed in the housing, but have no active parts. No extra split lines or parts are needed as all input is captured by the light emitters and receivers beneath the surface. Typically, button controls  846  are used to select a mode or to start the machine and slider controls are used to adjust a value such as temperature or time. Slider controls  843  and  844  are actuated when a user glides his finger through the groove. 
     Reference is made to  FIG. 72 , which is a simplified illustration of an alternative control panel and associated user interface for a washing machine, in accordance with an embodiment of the present invention.  FIG. 72  shows an alternative washing machine control panel UI that is modeled on an intuitive “filling the washing machine” concept. Control panel  850  displays multiple settings. To set up a wash, the user drags and drops each setting into a round recessed area  851 . This avoids accidental selection, for example by a toddler or child touching the machine. Settings can be chosen in any order.  FIGS. 72(A)  and (B) illustrate a user dragging  852  a temperature setting into recessed area  851  using his finger  900 . 
     Reference is made to  FIGS. 73-76 , which are simplified illustrations of additional control panels for frontloading and top loading washing machines, in accordance with embodiments of the present invention.  FIG. 73  shows a washing machine  840  with a control panel  860  in the form of a ribbon surrounding the frontloading door.  FIG. 74  is a detailed view of control panel  860 . As shown in  FIG. 74 , control panel  860  is an arc-shaped ribbon in which an array of tap-activatable icons are arranged along the arc. Touch detention is accomplished by an array of light emitters along the outer arc edge sending light beams across the width of panel  860  to an array of receivers along the inner arc edge. Light guide  861  is situated along the outer arc edge for guiding light from the emitters across the panel, and light guide  862  is situated along the inner arc edge for guiding the emitted light onto the receivers. These emitters and receivers are inside the washing machine housing; only a small light guide bezel from light guides  861  and  862  protrudes along the inner and outer arc edges to project the light beams over panel  860 . A user touching a control blocks a corresponding light beam from reaching its receiver. Alternatively, light emitters and receivers are arranged only along the outer arc. In this case, the receivers detect light from the emitters that is reflected by a user&#39;s finger touching one of the controls on panel  860 . When a user touches a control, that control illuminated. For example,  FIG. 74  shows controls  863 - 865  illuminated. When a plurality of controls are illuminated, configuring a wash cycle, the user presses start button  866  at the top of the control panel arc to begin the wash cycle. 
       FIG. 75  shows a top loading washing machine  840  with a control panel  870  according to embodiments of the present invention. A detailed view of control panel  870  is provided in  FIG. 76 . As shown in  FIG. 76 , control panel  870  has a slightly curved array of proximity sensors  871  along a row of icon controls  872 . When a user selects a control, selection is indicated either by illuminating the control or by illuminating a corresponding location on the curved proximity sensor array  871 . In  FIG. 76  both the selected controls and their corresponding locations on array  871  are illuminated. 
     In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made to the specific exemplary embodiments without departing from the broader spirit and scope of the invention. Accordingly, the specification drawings are to be regarded in an illustrative rather than a restrictive sense.