Abstract:
Provided is a cooking appliance that includes an oven cavity and an oven door is pivotally coupled adjacent to an entrance leading into the oven cavity, and a method of controlling such a cooking appliance. The oven door includes a substantially opaque region that interferes with external observation of the oven cavity while the door is in the closed orientation, and an electrochromic indicator provided to the opaque region. The electrochromic indicator includes a material with a first appearance that renders the electrochromic indicator substantially indistinguishable from the opaque region in a first operational state, and a second appearance in a second operational state that contrasts with the opaque region to issue a notification related to operation of the cooking appliance.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
       [0001]    This application relates generally to a method and apparatus for indicating an operational status of a cooking appliance and, more particularly, to a cooking appliance and corresponding method utilizing an indicator formed from an electrochromic material provided to a surface of the appliance to indicate an operational state. 
       2. Description of Related Art 
       [0002]    Oven ranges typically include an oven cavity and an oven door that restricts access into the oven cavity. To ensure sufficient access to the interior of the oven cavity and allow large food items such as turkeys, cakes, etc. to be placed therein, the oven door is typically a large, planar structure that extends over most of the appliance&#39;s height. Efforts to maximize the volume of the oven cavity for cooking have only further increased the size of the oven door. Although many oven doors include a transparent window that allows food being cooked to be observed without opening the oven door, most of the remaining externally-exposed surface of the oven door serves no function other than to provide the closed oven cavity with a pleasing aesthetic appearance. 
         [0003]    Due to the space required for the oven cavity/oven door, cooktops, and other functional features that are operable to emit heat and cook food, there is a limited amount of space remaining for other features. User interfaces for displaying relevant information, for example, and other such features that do not directly heat food must be small enough to fit on the remaining cabinet space not utilized by the cooking features. As a result, the amount of information that can be displayed and the size of the displayed information has traditionally been small. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    According to one aspect, the subject application involves a cooking appliance that includes an oven cavity in which a food item is to be exposed to an elevated temperature established by a heating element to be cooked. An oven door is pivotally coupled adjacent to an entrance leading into the oven cavity to be adjusted between an open orientation and a closed orientation to selectively grant entry to the oven cavity. The oven door also includes a substantially opaque region that interferes with external observation of the oven cavity while the door is in the closed orientation. An electrochromic indicator is provided to the opaque region of the oven door. The electrochromic indicator includes a material with a first appearance that renders the electrochromic indicator substantially indistinguishable from the opaque region in a first operational state and a second appearance in a second operational state that contrasts with the opaque region to issue a notification related to operation of the cooking appliance. 
         [0005]    According to another aspect, the subject application involves a method of providing a notification related to operation of a cooking appliance including an oven cavity and an oven door restricting access to the oven cavity. The method includes receiving an instruction entered via a control panel provided to the cooking appliance to establish a desired operational state of the cooking appliance involving the oven cavity. A voltage is established across a material of an electrochromic indicator provided to an opaque region of the oven door to transition an appearance of the material from a first appearance resembling an opaque portion of the oven door to a second appearance that contrasts with the opaque region to issue a notification related to the desired operational state of the cooking appliance. 
         [0006]    The above summary presents a simplified summary in order to provide a basic understanding of some aspects of the systems and/or methods discussed herein. This summary is not an extensive overview of the systems and/or methods discussed herein. It is not intended to identify key/critical elements or to delineate the scope of such systems and/or methods. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later. 
     
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWING 
         [0007]    The invention may take physical form in certain parts and arrangement of parts, embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and wherein: 
           [0008]      FIG. 1  is a perspective view of an oven range in accordance with an illustrative embodiment; 
           [0009]      FIG. 2  is a front view of an illustrative embodiment of an oven door with a plurality of electrochromic indicators provided to an opaque region, the electrochromic indicators being in their native operational state in the absence of an applied voltage; 
           [0010]      FIG. 3  is a front view of the illustrative embodiment of the oven door appearing in  FIG. 2 , but with the plurality of electrochromic indicators shown in their driven operational state in the presence of a voltage applied across each electrochromic indicator; and 
           [0011]      FIG. 4  is a sectional view of a region of the oven door appearing in  FIGS. 2 and 3  provided with a coating material forming a portion of an electrochromic indicator, and a control that controls delivery of electric energy from a power supply to the electrochromic indicator. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. Relative language used herein is best understood with reference to the drawings, in which like numerals are used to identify like or similar items. Further, in the drawings, certain features may be shown in somewhat schematic form. 
         [0013]    An illustrative embodiment of a cooking appliance  10  is shown in  FIG. 1 . As shown, the cooking appliance  10  is an oven range that includes a cabinet  12  supporting a cooktop surface comprising a plurality of surface burners  14 . A grate  18  is provided to support a pot, pan or other cooking vessel at an elevation vertically above the burners  14  so food in the cooking vessel can be heated by the burners  14 . Although the cooking appliance  10  in  FIG. 1  includes a gas cooktop with burners  14  that combust a gas to generate flames for heating food in cooking vessels, alternate embodiments of the cooking appliance  10  can instead include an electric cooktop with a plurality of resistive heating elements that, when energized with electric energy from a power source such as an AC mains outlet supplied by an electric utility, emit heat. Such resistive heating elements can be exposed at the cooktop surface to support the cooking vessels or disposed beneath a glass-ceramic surface that supports the cooking vessels vertically above such burners. According to yet other embodiments, the cooking appliance  10  can include an inductive cooktop instead of a gas or electric cooktop. For such embodiments, inductive elements arranged beneath a glass-ceramic cooktop surface conduct an alternating electric current to generate an oscillating magnetic field which, in turn, induces eddy currents in ferrous cooking vessels to generate heat. Yet other embodiments of the cooking appliance  10  can lack a cooktop altogether, including only an oven cavity  15  described in detail below. 
         [0014]    The cooking appliance  10  in  FIG. 1  also includes an oven cavity  15  (the interior of which is shown in the cutaway section of the cabinet  12 ) in which a food item is to be exposed to an elevated temperature established by one or more heating elements  19  in order to be cooked. Similar to the cooktop described above, the oven cavity  15  can optionally be heated by energizing the heating element(s)  19  using any desired fuel. For the example shown in  FIG. 1 , the heating element  19  includes a serpentine tube through which a combustible gas (e.g., natural gas, propane, etc.) supplied by a residential gas line, for example, travels and is emitted through an array of small holes formed in the walls of the tube. The emitted gas is combusted to generate the heat that elevates the temperature within the oven cavity  15 . However, alternate embodiments of the heating element  19  can again be energized by electricity from an AC mains outlet supplied by an electric utility. The resistance of the heating element  19  results in the generation of heat to elevate the temperature within the oven cavity  15 . The heating element  19  can be any type of heat emitting device in thermal communication with the oven cavity  15  to provide a heating effect to the oven cavity  15 , and thereby elevate the temperature therein to a desired cooking temperature. Regardless of the type of heating element  19 , the heating element  19  can include a bake element arranged adjacent to the bottom of the oven cavity  15 , a broil element arranged adjacent to the ceiling of the oven cavity  15 , or a combination thereof. 
         [0015]    A control panel  17  is provided with a plurality of control knobs  20  or other input devices (e.g., tactile push buttons, a touch-sensitive computer display device, capacitive touch sensors, etc.), or a combination of different input devices, to allow a user to control operation of the cooktop burners  14  and/or heating element(s)  19 . Via the control panel  17 , users can initiate one or more of a plurality of different operational states available for that cooking appliance  10 , including at least one of: pyrolytic oven cleaning, baking, broiling, preheating, keeping food warm following completion of a cooking operation, and any other operational state involving the oven cavity  15 . 
         [0016]    An oven door  16  is pivotally coupled by one or more hinges adjacent to an entrance through which food is inserted into, and removed from the oven cavity  15 . The oven door  16  is adjustable between an open orientation and a closed orientation (closed orientation shown in  FIG. 1 ) to selectively grant entry to the oven cavity  15  and enclose the oven chamber from the ambient environment of the cooking appliance  10 , respectively. The oven door  16  in  FIG. 1  includes a window  21  that allows for external observation of the oven cavity  15  (e.g., the interior of the oven cavity  15  can be viewed through the window  21  from a vantage point of a user standing in front of the cooking appliance  10 ) while the oven door  16  is in the closed orientation. Surrounding the window  21  is a frame  24  region that couples the window  21  to the oven door  16  and forms an opaque region that interferes with external observation of the oven cavity while the door is in the closed orientation. In other words, the window  21  is substantially transparent, allowing food within the oven cavity  15  to be viewed from a vantage point in front of the cooking appliance  10 . Being opaque, the frame  24  does not allow light to pass there through, and blocks the view of the oven cavity  15  (and any food therein) from the vantage point in front of the cooking appliance  10 . For example, embodiments of the frame  24  can be made of a stainless steel, brushed aluminum, or other metallic material that can be a conductor of electricity having a conductivity of at least 1×10 6  S/m at 20° C. For such embodiments, the material forming the frame  24  can be utilized as an electrode to electrically connect material forming an electrochromic indicator  27  ( FIGS. 2 and 3 ) to an energy source  34  ( FIG. 4 ) (e.g., electric power supply) and/or a reference voltage (e.g., ground) as described in detail below. However, according to alternate embodiments, the externally-exposed surface of the frame  24  can be formed from a plastic material insulated from the elevated temperatures within the oven cavity  15  by an insulating material disposed between the plastic material and the oven cavity  15 . 
         [0017]    As illustrated in  FIGS. 2 and 3 , an electrochromic indicator  27 , or optionally a plurality of electrochromic indicators  27  can be provided to an outwardly-exposed surface the opaque frame  24  of the oven door  16 . Each electrochromic indicator  27  includes a material  29  ( FIG. 4 ) that is coated onto or otherwise applied (e.g., screen printed, etc.) to the outwardly-exposed surface of the oven door  16  to form a desired shape and/or pattern. For example, the electrochromic indicators  27  shown in  FIGS. 2 and 3  include a checkmark  30  arranged above a warning triangle  32  with an exclamation point “!” therein. Each electrochromic indicator  27  has a fixed shape and/or pattern, so every time a particular electrochromic indicator  27  is energized or otherwise rendered active, that electrochromic indicator  27  will have the same appearance. In other words, the electrochromic indicators  27  can be toggled between on and off, or active and inactive states to uniquely signal that a predetermined operational state of the cooking appliance  10  involving the oven cavity  15  is active, as opposed to computer displays and seven-segment displays, for example, which are dynamic and take on different appearances to display a variety of different information. According to alternate embodiments, although the electrochromic indicators  27  can include a fixed shape, such electrochromic indicators  27  can be activated to signal the occurrence of different events and/or conditions. For example, the checkmark  30  can be illuminated to signal the expiration of a timer while the cooking appliance  10  is operational in a first mode. Thus, activation of the checkmark  30  can notify an observer that a timed baking cycle is complete. However, the checkmark  30  could also be illuminated to signal the occurrence of a different event, such as a preheat temperature specified by the user being reached within the oven cavity  15 . 
         [0018]    In the illustrative embodiment shown in  FIGS. 2 and 3 , the electrochromic indicators  27  include a check mark  30  and a warning triangle  32  that each, when active, indicates a different operational state. For example, the check mark  30  can be activated and displayed to indicate expiration of a timer, and the warning triangle  32  can be activated and displayed to indicate when the oven is undergoing pyrolytic cleaning (e.g., the oven temperature is raised to a temperature of at least 700° F.). Such electrochromic indicators  27  can optionally have a dimension extending in a direction of the oven door&#39;s height of at least one inch, or at least two inches, and a dimension extending in a transverse direction across a width of the oven door  16  of at least one inch, or at least two inches. Regardless of the specific dimensions, the electrochromic indicators  27  are visible, comprehensible and distinguishable from each other at a distance of at least ten (10 ft.) feet from the cooking appliance  10 , or at least fifteen (15 ft.) feet from the cooking appliance  10 , when the electrochromic indicators  27  are active. 
         [0019]    With reference to  FIG. 4 , the electrochromic indicator  27  includes an electrochromic material  29  ( FIG. 4 ) applied to an externally-exposed surface of the frame  24 . This material can change color (e.g., from one color to another color), state (e.g., from transparent to a colored, translucent or opaque state), or otherwise be adjustable from a state in which it is not readily distinguishable from the frame material  24  on which it is applied to a state in which it is visible and distinguishable from the frame material  24  in response to application or removal of a voltage across the material  29  by a source  34 . Thus, in an inactive state, the electrochromic indicators  27  blend in with the frame material  24 , causing the frame material  24  to appear as if it is devoid of the electrochromic indicator  27  when viewed from a distance. In an active sate, however, the electrochromic indicators  27  contrast with, and stand out from the frame material  24  to be visible and distinguishable from the background. Examples of suitable materials that exhibit electrochromic properties include, but are not limited to: tungsten oxide (WO 3 ), nickel oxide (NiO), polyaniline, and other substances that exhibit an adjustable appearance as described herein. 
         [0020]    For example, the native color of the electrochromic material  29  in the absence of an applied voltage can substantially match the color of the externally-exposed surface of the frame material  24 . When the voltage is applied across the electrochromic material  29 , the color of the electrochromic material  29  transitions from its native color to a second color that contrasts with the color of the externally-exposed surface of the frame material  24 . When the voltage is subsequently removed, the electrochromic material  29  returns to its native color. 
         [0021]    According to an alternate embodiment, the electrochromic material  29  can be substantially transparent in a native state in the absence of an applied voltage. In this state, the externally-exposed surface of the frame material  24  is visible through the transparent electrochromic material  29 . Upon the occurrence of a predetermined event involving the oven cavity  15  or cooking appliance  10 , the voltage can be applied across the electrochromic material  29  to cause the electrochromic material  29  to transition to a substantially opaque state. 
         [0022]    In the foregoing description, the electrochromic indicators  27  are described as being “not readily” distinguishable from the frame material  24 , “substantially” matching the color of the frame material  24 , and “substantially” transparent in their inactive state. Such terms of degree do not necessarily require the electrochromic indicators  27  to be absolutely invisible in their inactive state, but only that they do not stand out from the frame material  24  to the same extent as when the electrochromic indicators  27  are active. In other words, a careful observer specifically looking for the electrochromic indicators  27  in their inactive state may be able to discern their location upon close inspection of the oven door  16 . However, the inactive electrochromic indicators  27  in their inactive state are not visible to a casual observer of the cooking appliance  10  who is not specifically looking for the electrochromic indicators, but is only viewing the cooking appliance  10  in passing, and from a distance. 
         [0023]    Referring again to  FIG. 4 , the source  34  is operatively connected to the electrochromic material  29  by a first electrode  36  that conducts electric energy from the source  34  to apply the voltage across the electrochromic material  29 . For embodiments where the door material  24  forming the opaque region of the oven door  16  is an electrically-conductive material, this door material  24  can form a second electrode electrically connecting the electrochromic material  29  to a reference voltage such as a ground potential, for example. 
         [0024]    A controller  38  includes a suitably-programmed microprocessor or other control circuitry to control switching devices for applying and removing the voltage supplied by the source  34  to control activation and deactivation of the electrochromic indicators  27 . The controller is configured to activate one or more of the electrochromic indicators  27  in response to determining that a specific event has occurred. For example, the controller  38  can be operatively connected to receive communications from the control panel  17  indicative of user-entered commands and instructions governing operation of the heating element(s)  19  and optionally one or more of the cooktop burners  14 . The controller  38  can reference a lookup table or other data source stored in a computer-readable memory provided to the controller  38  to determine a triggering event corresponding to the operational state of the cooking appliance  10  that is to be signaled through activation of one or more of the electrochromic indicators  27 . 
         [0025]    For example, the controller  38  can be configured to activate the electrochromic indicator  30  in response to a determination that at least one of the following has occurred: a pyrolytic oven cleaning cycle has been completed, a baking cycle has been activated by the user via the control panel  17 , a preheat temperature specified by the user via the control panel  17  has been reached within the oven cavity  15 , a broiling cycle has been activated by the user via the control panel  17 , a timer has expired to mark the end of a cooking operation (e.g., baking, broiling, cooktop heating, etc.), the heating element(s)  19  are operating to keep food warm following completion of a cooking operation involving the oven cavity  15 , and any other completed event involving the cooking appliance. Likewise, the electrochromic indicator  32  can be activated to indicate that an unexpected and/or undesirable event involving the cooking appliance  10  has occurred, or any other event involving the oven cavity  15  and/or cooktop. 
         [0026]    Embodiments of the electrochromic indicators  27  may be formed from a material that requires an extended period of time for its appearance to transition from the inactive state to the active state. For example, that change of appearance that results from transitioning from the inactive to the active state can take longer than one (1 sec.) second, and optionally longer than two (2 sec.) seconds to complete. Depending on the electrochromic material  29  utilized, this transition can take longer than five (5 sec.) seconds to fully complete. In view of time constraints of transitioning the electrochromic material  29  from an inactive state to an active state, embodiments of the controller  38  can be configured to update the state of the electrochromic indicator  27  to provide a visible indication of conditions that are scheduled to be updated no more than once in a one (1 min.) minute period, or optionally no more than once in a two (2 min.) minute period. 
         [0027]    Illustrative embodiments have been described, hereinabove. It will be apparent to those skilled in the art that the above devices and methods may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all such modifications and alterations within the scope of the present invention.