Patent Publication Number: US-8115120-B2

Title: Electrical switch with multiple switching channels

Description:
RELATED APPLICATIONS AND CLAIM OF PRIORITY 
     This patent application claims priority to French Application No. 0756695, filed Jul. 24, 2007, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     The recent developments and rapid evolution of telecommunications, for which the control of diverse functions anticipates, for example, moving a cursor precisely and quickly on a screen, makes it necessary to have electromechanical components of increasingly small size and to combine several electrical switching functions within a single component. 
     It may be desirable to have an electrical switch with multiple switching channels using a single actuating member that can be operated with one finger. Such operations, for example by using the lower face of the thumb of the user who is holding the device in his palm, may be easy and able to be carried out in as many directions as possible, with very good ergonomics and low operating forces (less than 2 newtons). 
     In addition, such a miniaturized component may provide its user with a tactile sensation reflecting the validity of operations carried out. The tactile sensation transmitted by the switch to the user may be a very important parameter for its performance and ergonomics. 
     The document filed under Application FR 06/51319 describes a switch of this type, the upper face of its upper panel being divided into several contact areas with each of which the pointing element is able to come into contact, and electrical switching elements associated with the contact areas and the state of which changes when the pointing element comes into contact with the associated contact area. 
     The switch also includes an element enabling a tactile sensation to be produced that is similar to a “click” of a conventional push-button in returning from a control action carried out by the user on the switch. 
     According to that document, the switch includes an intermediate plate to cause the change in state of the switching elements which is mounted so as to move relative to the upper panel and relative to the support frame in order to enable a distinct change in state of the switches and of the element producing the tactile sensation. 
     However, according to that document, the difference in amplitudes between a control action applied to the center of the upper panel and a control action applied to the periphery of the upper panel is relatively large, which may disturb the user who is acting on the switch. In addition, the movements of the upper panel and the plate relative to each other, and relative to the frame, entail a large vertical stroke of the upper panel, which runs counter to a concern for miniaturization. 
     SUMMARY 
     An electrical switch may control an electronic device with several switching channels divided around a main vertical axis of the actuator. 
     In an embodiment, an electrical switch with multiple switching channels may include a support frame. The support frame may be a lower horizontal support frame. The electrical switch may include a panel. The panel may be a an upper horizontal panel. The panel may be mounted in a mobile manner relative to the frame and a face with which a pointing element is configured to come into contact. In an embodiment, the panel may be mounted in a vertically mobile manner relative to the frame. In an embodiment, the face may be an upper horizontal face. The electrical switch may include a location element for locating the point of contact of the pointing element on the face of the panel, including a plurality of electrical switching elements, each of which is associated with a switching channel, which are configured to change state selectively, depending on the position of the point of contact, when the pointing element comes into contact with the face of the panel. 
     In an embodiment, the electrical switch may include a detection element which detects at least one control action which are configured to establish an associated switching channel when a pressing force with a value greater than or equal to a threshold value is exerted on the face of the panel by the pointing element. The establishment of the switching channel may be independent of the position of the point of contact with the face of the panel. 
     In an embodiment, the electrical switch may include an intermediate plate that may be arranged vertically between the upper panel and the frame, and on which the upper panel may act in order to cause the change in state of the switching elements. 
     In an embodiment, an electrical switch as previously described, may include an intermediate plate that is configured to cause the change in state of the switching elements and is configured to act on the detection element under the action of the panel, and in that the plate is at least partly deformable in order to actuate the detection element which detects the control action after changing the state of the switching elements. 
     In an embodiment, the detection element may be arranged at the center of the panel. In an embodiment, the detection element may be arranged horizontally at the center of the upper panel. The switching elements may be distributed around the detection element. 
     In an embodiment, the intermediate plate may include a central portion for actuating the detection element and may include portions extending radially outwards from this central portion. The outer radial end of each radial portion may be configured to cause the change in state of a switching element which is associated with the radial portion. The intermediate plate may be configured to deform such that each radial portion is configured to rock entirely about its inner radial end connecting it with the central portion of the intermediate plate in order to change the state of the associated switching element, and such that each radial portion is configured to rock about its outer radial end to actuate the detection element. 
     In an embodiment, the outer radial end of each radial portion may include a boss which may project downwards relative to the radial portion, and which may be configured cooperate with the associated switching element. The boss may be configured to press downwards on the frame such that the radial portion rocks about the boss to actuate the detection element. 
     In an embodiment, the panel may include a plurality of lower fingers, each of which is associated with a radial portion of the intermediate plate, which extends from a face of the panel, with the lower free end of the finger being configured to press downwards on the associated radial portion. In an embodiment, the plurality of lower fingers, may extend vertically downwards from a lower face of the upper panel. Each lower finger may be positioned radially such that it presses on the associated radial portion at a point of contact situated radially between the outer radial end and the inner radial end of the connection. 
     In an embodiment, the intermediate plate may be made in one piece by cutting and bending an elastically deformable metal plate. The central portion of the intermediate plate may include a pusher made of an elastically deformable material, which is connected to the inner ends of the radial portions. 
     In an embodiment, the detection element may include a single element forming a releasable stop for the central portion of the intermediate plate, in moving downwards, and which may be configured to change state when the control action is carried out on the panel. The switch may include an elastic element for returning the panel to a rest position. In an embodiment, the panel may be an upper panel. In an embodiment, the rest position may be a high first position. Each switching element may include two electrical contacts which may be carried by the frame and which may be configured to be electrically connected by an associated metal tongue under the action of the panel. 
     In an embodiment, the metal tongue maybe elastically deformable in order to connect to the electrical contacts. All the metal tongues may be part of a single metal piece including a central ring connected to an electrical contact common to all the switches. The outer radial end of each radial portion of the intermediate plate may be configured to press on an associated tongue in order to actuate the switch. In an embodiment, the intermediation place may press downwards. An intermediate protection film may be arranged between the intermediate plate and the metal piece. In an embodiment, the intermediate protection film may be vertically arranged. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Aspects, features, benefits and advantages of the embodiments described herein will be apparent with regard to the following description, appended claims, and accompanying drawings where: 
         FIG. 1  is a schematic exploded perspective representation of a switch according to an embodiment; 
         FIGS. 2 to 6  are sections along a vertical plane of the switch represented in  FIG. 1 , showing various actuation positions of the upper panel according to an embodiment; and 
         FIGS. 7 to 9  are sections similar to those of  FIGS. 2 to 4 , showing various actuation positions of a switch according to other embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     As used herein and in  FIG. 1 , the use of the term vertical, longitudinal and transverse as directions (V, L, and T respectively) are non-limiting and the device and elements of the device may be depicted in any configuration. In an embodiment, the vertical direction V corresponds in an arbitrary manner to the orientation of  FIG. 1  and without any reference to the Earth&#39;s gravity. 
     In  FIG. 1 , an electrical switch  20  may be represented which is intended to control the various functions of an electronic device such as, for example, a portable telephone or a computer. 
     The switch  20  may include a vertical stack including a lower support frame  22  and an upper panel  24  which may be mounted so as to move overall vertically relative to the frame  22 . 
     According to the embodiment represented in particular in  FIG. 1 , the switch  20  may be in the form of, but not limited to, a parallelepiped, such as, a horizontal square, having a vertical main axis of symmetry A. In an embodiment, the switch  20  may be in the general shape of a circular cylinder. 
     In order to control the functions of the electronic device on which the switch  20  is mounted, the user may use a pointing element (not shown) such as, but not limited to, a stylus or a finger, to bring the pointing element into contact with the upper horizontal face  24   s  of the upper panel  24 . 
     The switch  20  may include an element  26  for determining the position of the point of contact of the pointing element on the upper face  24   s  of the upper panel  24 . The element  26  may include a plurality of electrical switching elements  28 , such as, but not limited to, four, on which the upper panel  24  may be configured to act in a selective manner, depending on the position of the point of application of the pointing element, in order to cause the change in state of the switching elements  28 . 
     When a switching element  28  changes state, the switching element  28  may close an electrical circuit associated with it by establishing a switching channel of the switch  20 , enabling the flow of an electric current in this circuit through to an electronic control device (not shown) for the electronic apparatus, in order to cause a predefined action, such as, for example, the movement of a cursor on a display screen in a direction associated with the position of the point of contact of the pointing element with the upper face  24   s  of the upper panel  24 . 
     The switching elements  28  may be configured to be actuated in a selective manner by the upper panel  24  under the action of the pointing element and depending on the position of the pointing element on the upper face  24   s  of the upper panel  24 . 
     As mentioned further above, the switch  20  may be, but is not limited to, the overall form of a horizontal square. In an embodiment, the switching elements  28  may be preferably located at the corners of the square. In an embodiment, there may be four switching elements  28 . The switching elements  28  may be arranged in such a way that when the pointing element is pressed on the upper panel  24  at a lateral edge of the upper panel  24  two adjacent switching elements  28  may be actuated simultaneously or almost simultaneously. When the pointing element is pressed on the upper panel  24  at the center of the upper panel at least two switching elements  28  that are radially opposite relative to the vertical axis A of the switch  20  may be actuated. 
     Each switching element  28  may include two electrical contacts  62   a ,  62   b  which may be mounted on the frame  22  and which may be configured to be electrically connected by a metal tongue  30  of the switching element  28  under the action of the upper panel  24 . 
     Each metal tongue  30  may be made of an electrically conductive material. The metal tongue  30  may include a first end  30   a  which ma be connected in a permanent manner to a first electrical contact  62   a , and a second free end  30   b  which may be situated at a distance from the second electrical contact  62   b.    
     The metal tongue  30  may be configured to be elastically deformed under the action of the upper panel  24  in such a way that its second end  30   b  may come into contact with the second electrical contact  62   b  in order to establish the associated switching channel. 
     Each switching element  28  may be of the normally open type. The metal tongues  30  of all the switching elements  28  may be made by cutting and bending from a single horizontal metal piece  34 , which simplifies the production of the switch  20 . 
     In an embodiment, the first end  30   a  of each metal tongue  30  may be connected to a central metal ring  36  of the metal piece  34 , which may be centered on the main vertical axis A of the switch  20  and which may be in permanent contact with a common electrical contact  62   a , which may constitute the first electrical contact of each switching element  28 . 
     The switch  20  may include a detection element  38  to detect an additional control action by applying a pressing force to the upper face  24   s  of the upper panel  24 , the value of which may be greater than a threshold value, independently of the position of the point of contact of the pointing element on the upper face  24   s  of the upper panel  24 . 
     When carrying out the control action, the user may not be obliged to move the pointing element relative to the upper panel  24 . It may be possible to make use of a function of the electronic device which is directly linked to the position of the point of contact of the pointing element. 
     The detection element  38  which detects the control action may include an electrical switch which may be configured to establish another additional switching channel of the switch  20 . 
     This switch may be arranged on the frame  22  at the center of the switch  20  and it may include an elastically deformable element  40  which may be in the form of a dome that is coaxial with the main vertical axis A, domed upwards, and two electrical contacts  64   a ,  64   b  which may be configured to be connected by the deformable dome  40  when the user carries out the control action. 
     To do this, the circular peripheral edge  40   a  of the deformable dome  40  may be in permanent contact with a first electrical contact  64   a  and the central apex  40   b  may be situated vertically above and at a distance from the second electrical contact  64   b.    
     Hence, when the user carries out the control action, the apex  40   b  of the deformable dome  40  may move vertically downwards to come into contact with the second electrical contact  64   b  in order to connect it electrically with the first electrical contact  64   a.    
     The switch  20  may produce a single mechanical pulse on the upper panel  24  on return from the user&#39;s action by the pointing element and independently of the number of switching elements  28  that may be actuated by the upper panel  24 . This pulse may be transmitted by the upper panel  24  through to the pointing element to be felt by the user. 
     No matter what the position of the point of contact of the pointing element on the upper panel  24 , and no matter what the number of switching elements  28 , the user may feel a single mechanical pulse on return from the control action, in the same way he feels a pulse when pressing a conventional push-button. 
     As seen in the figures, producing the single pulse may include the deformable dome  40 , which may form a releasable or retractable stop for the upper panel  24  in a vertical position, which may be configured to change state when the value of the pressing force exerted by the pointing element on the upper face  24   s  of the upper panel  24  is greater than a threshold value. 
     While changing state, the deformable dome may  40  no longer form a stop for the upper panel  24 , which can then suddenly move downwards. During this sudden movement of the upper panel  24 , the user may feel a non-continuous variation in the resistance to movement of the upper panel  24 , which is interpreted by the user as a tactile sensation. The upper panel  24  may be mounted in a globally vertically mobile manner relative to the support frame  22 , in such a way that it may be configured to be moved downwards under the action of the pointing element. 
     The switch  20  may return the upper panel to a high position relative to the frame  22 , represented in  FIGS. 2 and 7 , when the user releases his action on the upper panel  24 . In an embodiment, the force for returning the upper panel  24  to its higher position may be exerted by an elastic element  42  which is compressed vertically between the upper panel  24  and the plate  22 . The elastic element  42  may include two upper longitudinal arms  44  which may be in contact with a lower face of the upper panel  24  and two transverse arms  46  which may connect the longitudinal arms  44  to each other. 
     The transverse arms  46  may be vertically curved, their concavity being directed upwards in such a way that the transverse ends of each transverse arm  46 , which is connected to a longitudinal arm, may be situated vertically at a distance from the frame and a central portion of each transverse arm  46  may be in contact with the frame  22 . 
     When the upper panel  24  moves downwards, the longitudinal arms  44  may move downwards, causing the elastic deformation of the transverse arms  46 . 
     As mentioned above, when the pointing element acts on the upper panel  24 , the switching elements  28  may change state selectively and the detection element  38  may be actuated when the user carries out the action called the control action. 
     The switch  20  may include an intermediate plate  48  which may be configured to cause the change in state of the switching elements  28  under the action of the upper panel  24 , and which may enable the change in state of all the switching elements  28  or only of certain switching elements  28  depending on the position of the point of contact of the pointing element, and which may allow the same switching elements  28  to be kept in this state when the user is carrying out the control action, without causing the change in state of the other switching elements  28 . 
     The plate  48  may be arranged vertically between the upper panel  24  and the frame  22 , and it may be produced in such a way that the upper panel  24  actuates the switching elements  28  by the plate  48 . The plate  48  may include a central portion  50  centered on the main vertical axis A and a radial portion  52  associated with each switching element  28 , which may extend radially relative to the vertical axis A from the central portion  50  and with the free radial end  52   a  of each radial portion  52  being configured to act on the associated switching element  28 . 
     In an embodiment, the plate  48  may be produced in such a way that it may be configured to actuate the detection element  38  to detect the control action under the action of the upper panel  24 . 
     As mentioned above, the plate  48  may include a central portion  50  which may be centered on the main vertical axis A of the switch  20 . In an embodiment, the plate  48  actuates the detection element  38  by its central portion  50  which may press downwards on the central apex  40   b  of the deformable dome  40 . 
     In order to concentrate the pressing force on the apex  40   b  of the deformable dome  40 , the central portion  50  of the plate  48  may bear a cylindrical pusher  54  that may be coaxial with the deformable element and the horizontal cross section of which may be reduced relative to the cross section of the central portion  50  of the plate  48 . The deformable dome  40  may constitute a stop that is releasable by moving the central portion  50  of the plate  48  downwards. According to an embodiment, the plate  48  may be configured to deform in order to actuate the detection element  38  after the change in state of the switching elements  28 . 
     In  FIGS. 2-9 , in order to act on the plate  48 , with a view to causing the change in state of the switching elements  28  and/or of the detection element  38 , the upper panel  24  may include a lower finger  56  associated with each radial portion  52  which may extend vertically downwards and which may be configured to press the associated radial portion  52  downwards at a point of contact situated between the outer end  52   a  and the inner end  52   b  of the radial portion  52 . 
     When the pointing element presses on the upper face  24   s  of the upper panel  24 , the upper panel  24  may move downwards relative to the frame  22  and at least one finger  56  may press on the associated radial portion  52  with a view to causing the change in state of at least one switching element  28 , depending on the position of the point of contact of the pointing element on the upper face  24   s  of the upper panel  24 . 
     As discussed above, the central portion  50  of the plate  48  may stop downwards on the deformable dome  40 . 
     As can be seen in  FIGS. 3 and 5 , a pressing of the finger  56  on the radial portion  52  may cause the rocking of the radial portion  52  relative to the central portion  50  about its inner end  52   b , which may not move downwards due to the stop position of the central portion  50 . The radial portion  52  may rock downwards until its outer end  52   a  is in a downwards stop position on the frame  22 . 
     In this stop position, the outer end  52   a  of the radial portion  52  may press downwards on the free end  30   b  of the associated metal tongue  30  in order to cause the change in state of the associated switching element  28  by closing it. 
     As shown in  FIGS. 4 and 6 , when the user increases the pressing force of the pointing element on the upper panel  24 , in order to carry out the control action, the force may be transmitted to the radial portion  52  by the finger  56 . The force may be transmitted to the deformable dome  40 , by the central portion  50  of the plate, and may cause a change in state of the deformable element when the value of the force exerted by the user reaches a maximum resistance value of the deformable dome  40 . 
     The deformable dome  40  may deform, allowing a downward movement of the central portion  50  and of the inner end  52   b  of the radial portion  52 , and the radial portion  52  may rock downwards about its outer end  52   a . The change in state of the deformable dome  40  has the consequence of actuating the detection element  38 , as well as a sudden downwards movement of the upper panel, which may be felt by the user as a tactile sensation. 
     According to an aspect of the plate  48 , as can be seen in  FIG. 2  and following, the outer radial end  52   a  of each radial portion  52  may include a boss  70  which may project downwards relative to the radial portion  52 . The radial portion  52  may push downwards on the associated tongue  30  by the boss  70 , when the switching element  28  is actuated, and it may rock about the boss  70  when the detection element  38  is actuated. 
     The position of the point of contact of the finger  56  on the radial portion  52 , between its two ends  52   a  and  52   b , along with the releasable stop of the central portion  50  of the plate formed by the deformable dome  40 , may cause a rocking of the associated radial portion  52  about each of the radial ends  52   a ,  52   b , according to the action the user carries out on the upper panel  24 . 
     The distribution of the fingers  56  relative to the upper panel  24  may be determined so as to divide the upper face  24   s  of the upper panel  24  into several contact areas  58  and  60 . 
     For example, referring to  FIGS. 2-9 , the upper panel  24  may have two fingers  56  distributed on both sides of the main vertical axis A and which may divide the upper face  24   s  of the upper panel into three contact areas, namely a central contact area  58  situated entirely between the two fingers  56 , and two outer contact areas  60 , each of which extends radially outwards from a finger  56 . 
     The switch  20  may include a film  66  protecting the electrical contacts which may cover the metal piece  34  and the deformable dome  40  and which may be arranged vertically below the plate  48 . The protection film  66  may prevent various polluting elements such as, but not limited to, dust or moisture entering the switch  20  at the level of the electrical contacts  62   a ,  62   b ,  64   a ,  64   b  and the tongues  30 , which might impair proper operation of the switch  20 . The switch  20  may include an upper cage  68  enabling the components of the switch  20  to be joined to each other. 
     The operation of the switch  20  may be described with reference to  FIGS. 2 to 6 , which are axial sections through a switch  20 , which may include two switching elements  28  arranged on both sides of the main vertical axis A, and the detection element centered on the main vertical axis A. In addition, according to an embodiment, the plate  48  may be made of a single elastically deformable piece. 
     In  FIG. 2 , the switch  20  may be in the rest position, which is to say that no pointing element may be in contact with the upper face  24   s  of the upper panel  24 . The upper panel  24  may be in a high rest position relative to the frame, a position in which it may be kept by the elastic element  42 . The switching elements  28  and the detection element  38  may be in a rest position for which the switching channels associated with them are not established. 
     When the input device comes into contact with the upper face  24   s  of the upper panel  24  in an outer contact area  60 , as represented in  FIG. 3 , it may cause downward rocking of the upper panel  24  relative to the frame  22  about a pivot point situated at an edge of the upper panel, opposite the point of contact relative to the main vertical axis A. 
     The fingers  56  then may move downwards and the finger  56  that is closest to the point of contact of the pointing element on the outer contact area  60  then may come into contact with the plate  48 , at a radial portion  52 , and the finger  56  may press this radial portion  52  downwards. In an embodiment, the plate  48  may deform in such a way that the radial portion  52  on which the finger  56  may press downwards about its inner radial end  52   b  connecting it to the central portion  50  of the plate  48 . 
     The outer radial end  52   a  of the radial portion  52  may press on the associated tongue  30  (not represented in  FIGS. 2-9 ) by the boss  70  in order to cause the change in state of the associated switching element  28 . 
     The switching channel associated with the switching element  28  that has just changed state may be established, such that the electronic control device connected to the switch may receive a piece of information according to which the pointing element is in contact with the previously defined outer contact area  60 . 
     To carry out the control action, the user may increase the amplitude of the pressure force on the outer contact area  60 , as represented in  FIG. 4 , consequently causing an additional downward movement of the upper panel  24  and of the finger  56 . 
     The greater pressure of the pointing element on the upper panel  24  may be transmitted to the plate  48 , and more precisely to the radial portion  52  that has been moved downwards to cause the change in state of the switching element  28 . When a switching element  28  has changed state, the boss of the associated radial portion  52  may be stopped against the base of the frame  22 . 
     An additional force exerted by the finger  56  on the radial portion  52  may cause a rocking of the radial portion  52  downwards about its outer end  52   a , such that the inner end  52   b  of the radial portion  52  may move downwards. The central portion  50  of the plate  48  may be driven downwards, while joined to the inner end  52   b  of the radial portion  52 , in order to cause the change in state of the deformable dome  40  of the detection element  38 . 
     In an embodiment, the plate  48  may deform at the inner end  52   b  of the radial portion  52 , enabling a downwards movement of the central portion  50  without carrying along the outer ends  52   a  of the other radial portions  52 , so as not to cause the change in state of the other switching elements  28  when the detection element  38  is actuated. 
     When the input device comes into contact with the upper face  24   s  of the upper panel  24  at the central contact area  58 , as shown in  FIG. 5 , the force may be distributed over the upper panel  24 , relative to the elastic return element, such that the upper panel  24  slides vertically downwards relative to the frame  22 . 
     The two fingers  56  then may move downwards in one and the same movement, such that they both come into contact with the plate  48 , on the radial portions  52 . 
     According to an embodiment, the plate  48  may deform in such a way that the two radial portions  52  rock downwards relative to the central portion  50  about their inner radial ends  52   b . The central portion  50  may remain vertically immobile and may not therefore actuate the detection element  38 . 
     The outer radial end  52   a  of the radial portions  52  may cooperate with the tongues  30  to cause the change in state of the switching elements  28 . The switching channels associated with the switching elements  28  that have just changed state are established, such that the electronic control device connected to the switch  20  may receive a piece of information according to which the pointing element is in contact with the central contact area  58 . 
     To carry out the control action, the user may increase the amplitude of the pressure force on the central contact area  58 , as represented in  FIG. 6 , consequently causing an additional downward movement of the upper panel  24  and of the fingers  56 . The greater pressure of the pointing element on the upper panel  24  may be transmitted to the plate  48 , and more precisely to the radial portions  52 . As previously mentioned, when it causes the change in state of the associated switching element  28 , the outer end  52   a  of each radial portion  52  may be stopped against the base of the frame  22 . 
     An additional force exerted by a finger  56  on a radial portion  52  may cause a rocking of the radial portion  52  downwards about its outer end  52   a , such that the inner end  52   b  of the radial portion  52  may move downwards. The central portion  50  of the plate  48  may be driven downwards, while joined to the inner end  52   b  of the radial portions  52 , in order to cause the change in state of the deformable dome  40  of the detection element  38 . 
     According to an embodiment, the plate  48  may deform at the inner end  52   b  of the radial portion  52 , enabling a downwards movement of the central portion  50 . As mentioned above, the plate  48  may be made of a single piece and may be elastically deformable. During its first deformation, in order to cause the change in state of one or more switching elements  28 , the plate  48  may deform such that the central portion  50  becomes convex, domed upwards, as can be seen in  FIGS. 3 and 5 , and when the plate  48  deforms to cause the change in state of the detection element  38 , the central portion  50  becomes concave, open upwards, as can be seen in  FIGS. 4 and 6 . 
     Conversely, when the switch  20  is in the rest position, the plate  48 , and consequently the central portion  50 , may be entirely planar and horizontal. 
       FIGS. 7 to 9  represent another embodiment of the switch  20  to which the plate  48  may be made of several pieces attached to each other. The radial portions  52  are similar components, for example, made of cut and crimped sheet metal, and may be connected to the central portion  50 , which may be elastically deformable. 
     For example, the central portion  50  may be made by over molding plastic around the inner ends  52   b  of the radial portions. According to a variant, the pusher  54  may be produced from the same material as the central portion  50  by molding. 
     In  FIG. 8 , when the pointing element comes into contact with the upper face  24   s  of the upper panel  24 , the central portion  50  may deform to allow a downward rocking of a radial portion  52  about its inner end  52   b , until the outer end  52   a  of the radial portion  52  stops downwards against the frame  22 , causing the change in state of the associated switching element  28 . 
     The radial position of each finger  56 , relative to the main vertical axis A and relative to the associated radial portion  52 , and the radial length of the radial portion  52  may be determined such that the value of the pressing force to be applied to the upper panel  24  in order to change the state of the deformable dome  40  may varies moderately depending on the radial position of the point of contact of the pointing element on the upper face  24   s  of the upper panel  24 . 
     When a finger presses on the associated radial portion  52  to cause the downward rocking of the radial portion about its outer end  52   a , the force transmitted to the deformable dome  40  at the inner end  52   b  of the radial portion may be reduced due to the lever arm about the outer end  52   a  of the radial portion. 
     The radial portions  52  are preferably identical, and the fingers  56  may be arranged on the same radial side relative to the main vertical axis A of the switch  20 . When the control action is transmitted to the plate  48  by several fingers  56 , the radial portions  52  concerned may behave like a single force transmitter causing a reduction in the amplitude of the force identical to the reduction obtained by a single radial portion  52 . 
     When the control action is carried out on the central contact area  58 , the upper panel  24  may slide downwards relative to the frame  22 . The control action may be transmitted to the plate without being reduced in its amplitude. The amplitude of the control action that is transmitted to the deformable dome  40  may be reduced due to the force transmitted by the radial portions  52  that has just been described. 
     Conversely, when the control action is carried out on an outer contact area  60 , as mentioned above, the upper panel  24  may rock relative to the frame  22  about a pivot point opposite the point of contact of the pointing element on the upper panel  24 , relative to the main vertical axis A. The upper panel  24  may act as a lever arm transmitting the control action to the plate  48  at a finger  56  or adjacent fingers  56  which are the closest to the point of application of the control action. 
     The amplitude of the force transmitted to the plate  48  may be lower than the amplitude of the force transmitted when the control action is carried out on the central contact area  58 . 
     The force the user must exert on the upper panel  24  in order to cause the change in state of the deformable dome  40  may be greater when the user carries out the control action on the outer contact area  60  than when the user carries out the control action on the central contact area  58 . 
     The difference in amplitude between the force to be applied to an outer contact area  60  and the force to be applied to the central contact area  58  of the switch  20  according to and embodiment may be determined depending on the radial position of each finger  56  and depending on the length of the radial portions  52 . 
     In an embodiment, it may be possible to obtain a switch for which the amplitude of the force the user must exert on the upper panel  24  in order to cause the change in state of the deformable dome  40  is lower when the user carries out the control action on the outer contact area  60  than when the user carries out the control action on the central contact area  58 . 
     However, the difference in values between the force to be applied to an outer contact area  60  and the force to be applied to the central contact area  58  of the switch  20  according to an embodiment is less than the difference in values between the force to be applied to an outer contact area  60  and the force to be applied to the central contact area  58  for a switch. That may enable the user to hardly be disturbed in using the device equipped with the switch  20  according to an embodiment. 
     It may be possible to divide the upper face of the upper panel to form contact areas  58 ,  60 , in the manner of a telephone keypad, including, but not limited to, nine contact areas  58 ,  60  when the shape of the switch  20  is square, as represented in  FIG. 1 , or indeed, when the main shape of the switch  20  is circular, the upper face  24   s  of the upper panel  24  includes, but is not limited to, twelve outer contact areas  60  distributed around the central contact area  58  to form a numerical dial. 
     The switch may include a number of switching elements  28  defined depending on the number of contact areas  58 ,  60 , for example, but not limited to, that described in the document filed under Application FR 06/51319. 
     In addition, due to the lever arm function of each radial portion  52  and the position of the point of contact of each finger  56  on the radial portion, the amplitude of the downward vertical movement of the upper panel  24  relative to the frame  22  may be reduced relative to a switch. 
     In an embodiment, it is possible to produce a switch of reduced vertical size, which may be advantageous for its incorporation in a small-sized electronic device.