Patent Publication Number: US-2023137132-A1

Title: Interface for operating an elevator car, elevator car and method of producing an elevator car

Description:
FIELD 
     The present invention relates to an interface for operating an elevator car, to an elevator car and to a method of producing an elevator car. 
     BACKGROUND 
     Elevators are generally used for transporting persons or material from one level to another level, for example in a building. The elevator comprises an elevator car which may be moved between the various levels using a drive unit. The drive unit can be controlled by an elevator controller. 
     In order to enable activation of the elevator controller to drive the car to a specific level, operating panels are usually provided in the car or at the floor levels. For example, a car operating panel (COP) may be provided within the car as an interface between the elevator controller and a user of the elevator. A user of the elevator may use the car operating panel to provide a request to the elevator controller to move the elevator car to a specific floor level. A conventional car operating panel includes a panel plate and a plurality of push buttons reaching through the panel plate. Some car operating panels include a display device reaching through the panel plate, e.g. a segment display indicating floor numbers. Conventionally, the panel plate is mounted to a side wall of the elevator car or can form a portion of the side wall. 
     However, conventional car operating panels can have various disadvantages, in particular with respect to a space required for mounting a panel with its electrical components to a side wall of the car. Conventional car operating panels may have disadvantages with respect to the compatibility with curved side walls of an elevator car, or may have disadvantages with respect to servicing of the panel, e.g. cleaning of the panel. 
     SUMMARY 
     Accordingly, there may be a need for an interface for operating an elevator car, which is improved with respect to conventional car operating panels, particularly with respect to the required space, the compatibility with curved side walls or servicing. Furthermore, there may be a need for an elevator car including an interface according to embodiments described herein, or for a method of producing an elevator car comprising an interface. Such needs may be met with the subject matter of the advantageous embodiments defined in the following specification. 
     An aspect relates to an interface for operating an elevator car, comprising an interface controller, a foil for attachment to a wall surface of a wall of the elevator car, the wall surface facing an inside of the elevator car, and at least one pressure-sensitive sensor configured for receiving user requests by an application of a pressure to the at least one sensor, wherein the at least one sensor is connected to the interface controller, the interface controller being configured for transmitting the user requests received by the at least one sensor to a car controller of the elevator car, and wherein the at least one sensor is embedded in the foil. 
     Another aspect relates to an elevator car, comprising an interface according to embodiments described herein, and a wall having a wall surface facing an inside of the elevator car, wherein a foil of the interface is attached to the wall surface. 
     Yet another aspect relates to a method of producing an elevator car comprising an interface, particularly an interface according to embodiments described herein, the method comprising attaching a foil of the interface to a wall surface of a wall of the elevator car, wherein at least one pressure-sensitive sensor of the interface is embedded in the foil, and wherein the at least one sensor is configured for receiving user requests by an application of a pressure to the at least one sensor. 
     Embodiments of the present disclosure relate to an interface for operating an elevator car. In particular, the interface is configured for receiving user requests from a user of the elevator, e.g. from a person using the elevator to travel from one floor to another. The interface, in particular the at least one sensor of the interface, is configured for receiving a user request by an application of a pressure by the user to the at least one sensor. A pressure may be applied to a first sensor of the at least one sensor by touching or by applying a force onto a first region of the foil, wherein the first sensor is arranged in the first region of the foil. A user request can include for example a user input for selecting a destination floor, a request for closing a car door, a request for opening the car door, a request for an emergency call, or a request for ringing an emergency bell. In the present disclosure, the term “or” is to be understood particularly as “and/or”. 
     According to embodiments, the foil is configured for attachment to a wall surface of a wall of an elevator car. In some embodiments, the wall surface can be a region of the wall reaching to at least one side of the wall, a roof section of the elevator car or a floor of the elevator car. For example, the wall surface can be an entire surface of a wall, a wall region reaching to a roof section of the elevator car of a wall, a vertical or a horizontal stripe, e.g. a vertical stripe reaching from a floor of the elevator car to a roof section of the elevator car. In particular, connections, e.g. electrical circuitry, between the foil and the interface controller may advantageously be arranged outside an interior space of the elevator car. 
     In embodiments, the at least one sensor is embedded in the foil. Herein, the term “embedded” can be particularly understood such that the at least one sensor is not in contact with an inside of the elevator car. In some embodiments, the at least one sensor can be entirely enclosed by the foil. In further embodiments, the at least one sensor is at least substantially surrounded by the foil. For instance, one free side of the at least one sensor, e.g. a side facing the wall surface, may not be in contact with the foil. 
     According to embodiments, the at least one sensor is pressure-sensitive. In particular, the at least one sensor can be configured to detect a touch or a force applied to the foil, e.g. by a finger or a hand of a user. The touch or force applied to the foil can be transmitted through the foil as a pressure applied to the at least one sensor. In some embodiments, the pressure or the change in pressure may provide a change of a capacitance of the at least one sensor. The change of the capacitance can be detected by the interface controller, e.g. to determine a user request associated with a pressure applied to the at least one sensor. In contrast to some capacitive sensors, as used e.g. in some touch screens of smartphones, an interface having at least one pressure-sensitive sensor may provide the advantage that it can be operated independently of the capacitive properties of an object touching the interface. For example, an interface with at least one pressure-sensitive sensor may also be operated with “non-capacitive” gloves. 
     According to some embodiments, the foil comprises a protective layer between the at least one sensor and the inside of the elevator car. In particular, the protective layer of the foil can be in contact with the inside of the elevator car. The protective layer can be particularly configured for protecting the at least one sensor, e.g. from wear or from liquids. For example, the protective layer may have a thickness of at least 0.5 mm, particularly of at least 1 mm or at least 2 mm, or of maximum 5 mm, particularly of maximum 4 mm or maximum 3 mm. The protective layer may provide the advantage that the foil of the interface can be easily and thoroughly cleaned, particularly without the danger of damaging electrical components of the at least one sensor. 
     According to embodiments, the foil, particularly the foil comprising the embedding layer and the protective layer, has a thickness of maximum 5 mm, particularly of maximum 3 mm or of maximum 2 mm, or of minimum 0.5 mm, particularly of minimum 1 mm. The thickness of the foil is to be understood as the dimension of the foil in a direction perpendicular to the wall surface. The foil can be configured for attachment to a wall surface in a recess of the wall. An interface comprising a foil having a small thickness may advantageously allow for a seamless integration of the interface with the wall of the elevator car. In particular, the interface may be attached to a wall such that the foil is at least substantially flush with the wall, particularly without the need for holes in a wall to fit a conventional car operating panel. 
     In some embodiments, the protective layer comprises at least one sign indicative of a user request. The at least one sign may include at least one of a graphical sign and a tactile sign. For example, a graphical sign may be printed into or onto the protective layer. The at least one sign may include a tactile sign. A tactile sign may be formed as at least one elevation or at least one depression in the protective layer. In embodiments, each of the at least one sign is co-localized with at least one sensor. For example, a first sign of the at least one sign, the first sign being indicative of a first user request, may be co-localized with a first sensor of the at least one sensor in a first region of the foil, wherein the first sensor is associated with the first user request. 
     According to embodiments of the disclosure, the at least one sensor is embedded in an embedding layer of the foil, wherein the embedding layer is arranged between the protective layer and the wall surface. In particular, the at least one sensor can be at least substantially surrounded or entirely enclosed by the embedding layer of the foil. 
     In some embodiments, at least one of the foil, the embedding layer and the protective layer comprises a polymer or polymeric material. In particular, the polymer can comprise a synthetic or semi-synthetic organic compound. The polymer can be a plastic material. In some embodiments, at least one of the protective layer and the embedding layer may be produced from a plastic polymer or a liquid polymer, e.g. an adhesive polymer. For instance, the embedding layer may be molded around the at least one sensor to embed the at least one sensor. In some embodiments, the molding may be performed directly on the protective layer, the protective layer particularly supporting the at least one sensor. Molding may include a hardening process of the plastic polymer or liquid polymer, e.g. based on a change of temperature or a chemical reaction. In some embodiments, the embedding layer may be formed by injection molding around the at least one sensor, wherein the at least one sensor is arranged between the protective layer and a backside layer. In further embodiments, the protective layer and the embedding layer may be molded together. In yet further embodiments, the protective layer and the embedding layer may be produced separately. For instance, the protective layer and the embedding layer may be joined by a lamination process, e.g. by joining the protective layer and the embedding layer through an adhesive or by an application of heat and pressure. 
     According to embodiments, at least one of the foil, the embedding layer and the protective layer is flexible. The foil can be flexible such that the foil can be bent without breaking the foil and particularly without damaging the at least one sensor. In particular, the foil may be bent to a curvature of at least 2/m, particularly of at least 5/m or of at least 10/m. A curvature can be understood as the reciprocal of a radius of an osculating circle. In some embodiments, the foil can be configured flexible for attachment to a curved wall surface. For example, the curved wall surface may have a curvature of minimum 0.1/m, particularly of minimum 0.2/m or of minimum 0.4/m, or of maximum 10/m, particularly of maximum 5/m or of maximum 2/m. In embodiments, the foil may be attached to a flat wall surface. 
     According to some embodiments, at least one of the foil, the embedding layer and the protective layer is at least substantially transparent. In particular, “transparent” or “at least substantially transparent” may be understood such that at least 50% of an intensity of visible light is transmitted, particularly at least 70% or at least 80%. A transparent foil may advantageously enable the use of the interface with a wall made of glass without obstructing a view through the wall, or the use of the interface with a decorated wall without obstructing a view of the decoration. 
     According to embodiments, the interface comprises electric circuitry connecting the at least one sensor and the interface controller. In some embodiments the electric circuitry is at least partially embedded in the embedding layer of the foil. The electric circuitry may exit the foil at an edge of the foil, in particular at a top side of the foil. The electric circuitry may comprise conducting wires, which can be embedded in the foil. The wires can comprise a metal or a transparent conductor, e.g. a transparent conductive oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO), or a transparent conductive polymer. For example, each of the at least one sensor may be connected to at least one wire. The at least one wire may be connected to the interface controller or to a plug/socket interface. A plug/socket interface may be arranged for example at an edge of the foil, particularly at an edge of the foil, wherein the edge is not visible from an inside of the elevator car. In particular, the plug/socket interface may be arranged in a roof section of the elevator car. 
     According to some embodiments, the interface comprises at least one sensor for each user request, particularly one sensor for each user request. In particular, the interface may comprise at least two sensors, more particularly at least three sensors or at least four sensors, or maximum 70 sensors, particularly maximum 50 sensors or maximum 30 sensors. Each sensor of the at least one sensor can be connected to at least one wire. In embodiments with more than one sensor, a group of sensors of the at least one sensor may be arranged linearly, as an array or as a matrix. 
     In some embodiments, the at least one sensor comprises a high density sensor array configured as a touch area. The touch area may comprise a plurality of touch regions. The plurality of touch regions can comprise at least two request regions, wherein each of the at least two request regions is associated with a user request. The interface controller may be configured for determining to which region of the plurality of touch regions a pressure was applied by touching the foil. If the region is within one of the at least two request regions, the interface controller receives the associated user request. 
     According to some embodiments the at least one sensor has a thickness of maximum 1 mm, particularly of maximum 0.7 mm or maximum 0.5 mm. In some embodiments, the at least one sensor comprises a microelectromechanical system (MEMS). In particular, the at least one sensor may comprise components between 1 μm and 100 μm in size. 
     According to embodiments, the at least one sensor comprises a cavity and a membrane, wherein the at least one sensor is configured for sensing of a pressure applied to the at least one sensor based on a bending of the membrane into the cavity. In particular, a sensor of the at least one sensor may comprise a base layer, wherein the cavity is arranged on a base layer surface. The membrane may at least partially span the base layer surface such that the membrane is suspended over the cavity. By applying a pressure to the sensor, the membrane can be bent into the cavity. In embodiments, the membrane is arranged between the base layer and a protective layer of the foil. In further embodiments, the membrane can be arranged between the base layer and the wall surface. 
     In some embodiments, the sensor can be configured to provide a change of a capacitance of the sensor upon bending the membrane into the cavity. In particular, the membrane and the base layer may be configured to form a capacitor. For example, the base layer may comprise a base electrode layer. The membrane may comprise a membrane electrode layer. The base electrode layer and the membrane electrode layer may be connected to the interface controller. In particular, the interface controller may be configured to detect a change of the capacitance between the base electrode layer and the membrane electrode layer. A change of the capacitance can for example result from a decrease in distance between the base electrode layer and the membrane electrode layer, if the membrane is bent into the cavity. According to embodiments, the base layer comprises a base insulating layer between the base electrode layer and the membrane. In particular, the cavity can be formed in the base insulating layer. The membrane electrode layer can be provided on a supporting membrane layer. The supporting membrane layer may comprise a polymer, in particular a transparent polymer. The membrane electrode layer may be provided on a base side of the membrane, the base side facing the base layer of the sensor. 
     According to embodiments, the membrane electrode layer may comprise graphene, particularly globular graphene, e.g. graphene in the form of micro-spheres or “micro-bubbles”. Using globular graphene in the membrane electrode layer may advantageously provide a high conductance of the membrane electrode layer or may provide for a detection of a change of the capacitance based on a deformation of the globular graphene, if the membrane is bent into the cavity. According to embodiments, the base electrode layer may comprise a transparent conductive film, e.g. a film of a transparent conducting oxide such as ITO or IZO, a film of a transparent conductive polymer or a film of graphene. The base insulating layer may comprise an insulating material, particularly a transparent insulating material such a transparent polymer or glass. In embodiments, at least one of the at least one sensor, the membrane and the base layer can be transparent. 
     In some embodiments, each sensor of the at least one sensor comprises at least two cavities, particularly at least four cavities or a plurality of cavities, wherein the membrane spans the cavities. A sensor having more than one cavity may have a higher stability or provide a stronger signal, particularly without increasing a thickness of the sensor. 
     According to some embodiments, the interface controller is configured to provide a haptic feedback upon receiving a user request by injecting a charge into the at least one sensor. In particular, the at least one sensor can be configured to be expandable. For example, a sensor according to embodiments described herein may have a membrane suspended over a cavity of a base layer, wherein the membrane and the cavity form a capacitor. Injecting a charge into the capacitor may repel at least a suspended part of the membrane from the base layer. The membrane may expand the sensor such that the foil expands towards an inside of the elevator car to provide a haptic feedback. The interface controller may be configured to provide the haptic feedback within a time period of maximum 2 seconds, particularly maximum 1 second or maximum 0.5 seconds, upon receiving a user request. The haptic feedback can be particularly provided by the same at least one sensor which received the user request. 
     According to embodiments, the interface comprises a projector configured for installation in a roof section of the elevator car, the projector being configured for projecting information onto a projection surface of the elevator car. The projector may project information for a user of the elevator car, e.g. information concerning the operation of the car, for example a current floor number, a destination floor number or maintenance information. The projector can be configured to project the information on a projection surface in the upper 50% of the height of a cabin of the car, particularly in the upper 30% or the upper 20% of the cabin, wherein the cabin of the car is particularly the interior space of the elevator car. In some embodiments, the projection surface can be on the same wall as the wall surface to which the foil is attached. In particular, the projection surface can be arranged vertically above the at least one sensor or the projection surface can at least partially overlap with the wall surface. In further embodiments, the projection surface can be on a further wall different from the wall to which the foil is attached. The projector may provide white-light or colored projection beaming. 
     In embodiments, the projector is arranged in a roof section of the elevator car. In particular, the roof section can comprise at least one of a decorative roof, a car roof and a space between the decorative roof and the car roof. The decorative roof can form a roof to the cabin in the elevator car. In particular, a bottom side of the decorative roof is visible from the inside of the cabin. The car roof can form a roof of the elevator car. In some embodiments, the car roof and the decorative roof can be formed as a single roof. Providing a projector according to embodiments described herein can provide the advantage that information can be displayed, particularly without mounting a display into a wall of the elevator car. For example, an elevator car can be provided with a wall which does not have holes or deep recesses for mounting a car operating panel and a display. 
     According to embodiments, the interface controller is configured for connection to a car controller of the elevator car. The car controller can be arranged in a roof section of the elevator car. The car controller can be connected to an elevator controller of an elevator system, wherein the elevator system comprises the elevator car. The interface controller can be configured for arrangement outside an interior space of the elevator car, particularly outside a cabin of the elevator car. More particularly, the interface controller can be configured for arrangement in a roof section of the elevator car. In some embodiments the interface controller is formed as an individual controller. In further embodiments, the interface controller and the car controller can be arranged together in a controller structure. 
     According to embodiments, the interface may comprise at least one of a loudspeaker and a microphone. The loudspeaker or the microphone can be configured for installation in a roof section of the car. The loudspeaker and the microphone may particularly allow for an emergency call. Installing at least one of the loudspeaker and the microphone in a roof section may advantageously dispense with installing the loudspeaker or the microphone in a wall of the elevator car. 
     According to embodiments of the disclosure, an elevator car comprises an interface as described herein. The interface is attached to a wall surface of a wall of the elevator car, wherein the wall surface faces the inside of the elevator car. In some embodiments, the wall of the car can comprise for example glass, stainless steel or zinc sheet. In embodiments, an inner side of the wall may be decorated, wherein the inner side faces the inside of the elevator car. 
     According to some embodiments, the foil is attached to the wall surface by an adhesive layer. For example, an adhesive layer can comprise a synthetic resin, e.g. epoxy glue, or a silicone adhesive. In embodiments, the adhesive layer can be at least substantially transparent. 
     According to embodiments, the wall has a recess, wherein the recess comprises the wall surface and wherein the foil is arranged at least partially within the recess. In particular, the recess can have a depth which at least essentially corresponds to a thickness of the foil. For example, the depth of the recess may deviate from the thickness of the foil by maximum 30% of the thickness of the foil, particularly maximum 20% or maximum 10%. In embodiments, the recess may have a depth of maximum 7 mm, particularly of maximum 6 mm or maximum 5 mm. 
     In some embodiments, the foil is at least substantially flush with a further wall surface of the wall, the further wall surface being outside the recess. In particular, an inner surface of the foil, the inner surface facing the inside of the elevator car, can be flush with the further wall surface. The further wall surface can be a surface of the wall directly adjacent to the recess in the wall. “At least substantially flush” can be understood for example such that a deviation between an edge of the foil and the further wall surface does not exceed 3 mm, particularly 2 mm or 1 mm. Providing a foil that is at least substantially flush with a further wall surface can provide the advantage that the foil can be seamlessly integrated with the wall. 
     According to embodiments of the disclosure, a method of producing an elevator car comprising an interface, in particular an interface according to embodiments described herein, is provided. In embodiments, the method comprises attaching a foil of the interface to a wall surface of a wall of the elevator car. The foil may be attached to the wall surface by applying an adhesive, e.g. an adhesive layer, on the foil or on the wall surface. In some embodiments, attaching the foil comprises the application of at least one of temperature and heat. 
     According to embodiments, the method comprises installing at least one of a projector, a loudspeaker and a microphone in a roof section of the elevator car. In some embodiments, the method may comprise installing an interface controller in a roof section of the elevator car. In embodiments, the method can comprise connecting at least one of the foil, the projector, the loudspeaker and the microphone to the interface controller. 
     The interface according to embodiments described herein may provide various advantages over known car operating panels. For example, the interface may be integrated seamlessly with a wall of the elevator car. The interface may reduce a thickness of a wall or the space reserved for electrical components behind a wall. Without holes or deep recesses in the wall of the elevator car, the structural integrity of the wall may be improved. Further, an assembly of an elevator car may be simplified. Also, servicing of the interface may be simplified. For instance, the interface may be easily and thoroughly cleaned, particularly without a danger of damaging electrical components of the interface, e.g. by an exposure to liquids. Furthermore, the interface may be compatible with curved wall surfaces. The interface may allow for an advantageous integration with decorated walls or transparent walls. 
     In the following, exemplary embodiments of the disclosure will be described with reference to the drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a schematic view of an interface with a foil attached to a wall according to the invention; 
         FIG.  2    shows a schematic sectional view of an interface according to an embodiment; 
         FIG.  3    shows a schematic sectional view of an interface according to a further embodiment; 
         FIG.  4 A  shows a schematic sectional view of a sensor of an interface; 
         FIG.  4 B  shows a schematic sectional view of a sensor during an application of a pressure to the sensor; 
         FIG.  5    shows a schematic view of an elevator car according to an embodiment; and 
         FIG.  6    shows a schematic illustration of a method according to an exemplary embodiment. 
     
    
    
     The figures are only schematic and not to scale. Same reference signs refer to same or similar features. 
     DETAILED DESCRIPTION 
       FIG.  1    shows a schematic view of an interface  100 . The interface  100  comprises a foil  120 . The foil  120  is attached to a wall surface  152  of a wall  150  of an elevator car. The wall surface  152  reaches to a top side of the wall  150 , in particular to a roof section of the elevator car. The interface  100  comprises at least one sensor, in  FIG.  1    exemplarily illustrated as sensors  130 . The sensors  130  are connected via an electric circuitry  140  of the interface  100  to an interface controller  110  of the interface  100 . The interface controller  110  is configured for installation in a roof section of the elevator car. The electric circuitry  140  is partially embedded in the foil  120  and exits the foil at a top edge of the foil  120 . In  FIG.  1   , each of the sensors  130  is associated with a user request. Each sensor  130  is configured for receiving a user request by an application of a pressure to the sensor  130 . The sensors  130  are connected to the interface controller  110 , which is configured to detect an application of a pressure to a sensor  130  and to determine the respective user request. The interface controller  110  is configured for transmitting the user request to a car controller of the elevator car. 
       FIG.  2    shows a schematic sectional view of a foil  120  of an interface, as illustrated for example in  FIG.  1   . The foil  120  is attached to the wall surface  152  using an adhesive, for example using epoxy. The sensors  130  are embedded in the foil  120 . Each sensor  130  is connected to at least one wire of the electric circuitry  140 , the wires being embedded in the foil  120 . In  FIG.  2   , the wires comprise a transparent conductor. 
     In the exemplary embodiment of  FIG.  3   , a foil  120  of an interface  100  comprises a protective layer  324  and an embedding layer  322 . The protective layer  324  is arranged on an inner side of the foil  120 , wherein the inner side faces an inside of the elevator car. The embedding layer  322  is arranged between the protective layer  324  and the wall surface  152  of the wall  150 . The sensors  130  and the electric circuitry  140  are embedded in the foil  120 , in particular in the embedding layer  322  of the foil  120 . In  FIG.  3   , the sensors are arranged in contact with the protective layer  324 . In the exemplary embodiment, the embedding layer  322  is formed prior to attachment of the foil  120  to the wall surface  152  by molding of a polymer around the sensors  130  and the electric circuitry  140 , the sensors  130  and the electric circuitry  140  being pre-arranged on the protective layer  324 . 
     In  FIG.  3   , the protective layer  324  comprises signs  326  indicative of user requests. In particular, a sign  326  indicative of a first user request is co-localized with a sensor  130  associated with the first user request. In  FIG.  3   , the signs  326  are printed onto the protective layer  324 . 
       FIGS.  4 A and  4 B  show a schematic sectional view of an interface  100  with an exemplary pressure-sensitive sensor  130 . The sensor  130  is embedded in the foil  120 , which is attached to the wall surface  152 . The sensor  130  comprises a cavity  436  and a membrane  432 . The membrane  432  is suspended over the cavity  436 . The sensor  130  is configured for sensing of a pressure  439  applied to the at least one sensor  130  based on a bending of the membrane  432  into the cavity  436 , as shown for example in  FIG.  4 B . The pressure  439  may particularly result from a force  429  or touch applied to the foil  120  from an inside of the elevator car. The force  429  may be applied by a user using a hand or a finger, when providing a user request to the interface  100 . 
     In the exemplary embodiment of  FIGS.  4 A and  4 B , the cavity  436  is provided in a base layer  435  of the sensor  130 , in particular in a base insulating layer  437  of the base layer  435 . The base layer  435  comprises the base insulating layer  437  and a base electrode layer  438 , wherein the base insulating layer  437  is provided between the base electrode layer  438  and the membrane  432  of the sensor  130 . The base layer  435  comprises rigid material, in particular transparent rigid material. For example, the base electrode layer  438  comprises a transparent conductive oxide and the base insulating layer  437  comprises a transparent insulating material, e.g. a transparent oxide such as glass. The sensors  130  may be fabricated in a size such that a rigidity of the base layer  435  does not prevent an overall flexibility of the foil  120 . In further embodiments, a base layer may be fabricated from flexible material, particularly from material less flexible than the membrane. 
     The membrane  432  comprises a supporting membrane layer  433  and a membrane electrode layer  434 . The membrane electrode layer  434  is arranged between the supporting membrane layer  433  and the base layer  435 . In the exemplary embodiment of  FIGS.  3 ,  4 A and  4 B , the supporting membrane layer  433  comprises a polymer. The membrane electrode layer  434  comprises globular graphene. The membrane electrode layer  434  and the base electrode layer  438  form a capacitor. Upon application of a pressure  439  to the sensor  130 , the membrane  432  is bent into the cavity  436  and a capacitance of the capacitor is changed. The change of the capacitance can provide a change of a current or a change of a voltage on at least one of a base connection  442  and a membrane connection  444 , wherein the base connection  442  is connected to the base electrode layer  438  and wherein the membrane connection  444  is connected to the membrane electrode layer  434 . The connections  442  and  444  are connected to or are part of the electric circuitry  140 . Based on the change in current or voltage, the interface controller  110  can detect the application of the pressure  439 . Based on the detection of the pressure  439 , the interface  100  can receive the user request. 
       FIG.  5    shows a schematic view of an elevator car  560 . The elevator car  560  comprises a wall  150  and a further wall  568 . The wall  150  and the further wall  568  are arranged between an elevator floor section of the elevator car  560 , which includes a floor  566  of the elevator car  560 , and a roof section of the elevator car  560 . The roof section particularly includes a decorative roof  564 , a car roof  562  and a space between the decorative roof  564  and the car roof  562 . 
     The elevator car  560  of  FIG.  5    comprises an interface  500 . A foil  120  of the interface  500  is attached to a wall surface  152 , wherein the wall surface  152  is arranged in a recess  554  of the wall  150 . In particular, the foil  120  is flush with a further wall surface  556  of the wall  150 , the further wall surface  556  being directly adjacent to the recess  554 . In  FIG.  5   , the foil  120  extends or reaches up to the roof section of the elevator car  560 . The electric circuitry  140  exits the foil  120  in the roof section and connects the sensors  130  to the interface controller  110 . The interface controller  110  is connected to a car controller  558  of the elevator car  560 . For example, the car controller  558  is connected to an elevator controller of an elevator system (not shown), in which the elevator car  560  is arranged. 
     In  FIG.  5   , the interface  500  comprises a projector  570 . The projector  570  is arranged in the roof section of the elevator car  560 . The projector  570  is configured for projecting information, e.g. a current floor number, via a projector beam  572  onto a projection surface  574  of the elevator car  560 . In  FIG.  5   , the projection surface  574  is arranged on the wall  150 , particularly above the sensors  130  and overlaps with the wall surface  152 . An embodiment as shown exemplarily in  FIG.  5    may particularly provide the advantage that an interface  500  having sensors  130  for user input and a projector  570  for displaying information can be seamlessly integrated into an elevator car  560 . 
       FIG.  6    schematically illustrates an exemplary method  600  of producing an elevator car, particularly comprising an interface according to embodiments described herein. At a step  610 , the method  600  comprises attaching a foil of the interface to a wall surface of a wall of the elevator car. Attaching the foil to the wall surface comprises applying an adhesive layer to at least one of the wall surface or to the foil. At a step  620 , the method  600  includes installing a projector in a roof section of the elevator car such that the projector can project information onto a projection surface. At a step  630 , an interface controller is installed in the roof section. At a step  640 , the foil and the projector are connected to the interface controller. The interface controller is connected to a car controller of the elevator car. 
     Even though the invention of the present disclosure has been described with reference to exemplary embodiments, it should be noted that embodiments may be combined and modified in various ways without departing from the scope of the present invention. 
     In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.