Abstract:
A selector switch ( 10 ) for selecting or manipulating at least one function of a consumer product. The selector comprises an operating element having at least one operating area. The selector switch ( 10 ) comprises two momentary action switches ( 22,24;26,28;30,32;34,36 ) underneath the operating area to control the desired function.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application claims benefit under 35 U.S.C. § 120 from EP application EP 0 140 1968.1  
         FIELD OF THE INVENTION  
         [0002]    This invention relates to a multi-position push-button selector switch for selecting or manipulating at least one function of a consumer product.  
         BACKGROUND OF THE INVENTION  
         [0003]    In a selector switch such as described above, the operating element may be designed with a push-button switch or with a joystick, with a single key or momentary switch arranged underneath at least one area. Due to a component defect or operating errors the design may lead to mistriggering.  
           [0004]    Generally, a given function is controlled by a single key or momentary switch. For instance, in U.S. Pat. No. 5,902,972, a first switch triggers a first function (window down), a second switch triggers a second function (window up), whereas pressing both switches triggers a third function (automatic). Similarly, U.S. Pat. No. 5,796,056 relates to a multi-stage switch which is specifically designed so that an increasing force leads to a successive operation of different switch elements. U.S. Pat. Nos. 4,975,547 and 6,069,327 describe an arrangement of switches in combination with a multi-position switch where various functions are controlled depending on the combination of the various switch elements.  
           [0005]    Recent consumer electronic products, such as video recorders, monitors and the like have, for example, used a four or a multi-position push-button switch comprising a round button or cover for either selecting or navigating a required function. In order to have a uniform feel for the button itself, these buttons are designed so that the exemplary four switches are incorporated in a single piece.  
           [0006]    As the button is a single piece, and the functions are controlled by a single key stroke or momentary switch action, there is a possibility of accidentally triggering an adjacent function. The switches can be positionally located in quadrants, North, South, East and West positions. If a user wishes to select any one position, the users finger must press that particular position. If the user presses the plastic button between two switch locations, a detecting unit cannot detect the operation, or detects an unintended operation  
         SUMMARY OF THE INVENTION  
         [0007]    To avoid mistriggering caused by operating errors, a selector switch comprises two switches located underneath the operating area of the operating element to provide selectable control of the desired function.  
           [0008]    Compared to previous selector switches, each selectable function is advantageously controlled by two switches. Only when both switches belonging to the same operating area are activated, only then is the keystroke or button push recognized, otherwise the keystroke will be ignored.  
           [0009]    According to a preferred embodiment of the invention, the operating element comprises a single piece push-button, having several adjacent operating areas or segments with at least two switches positionally located underneath each operating area to provide selectable control of desired functions. Advantageously, if a user operates the push-button between two adjacent operating areas, then only one switch of the pair located under each operating area is pressed and activated. An advantageous detector is arranged such that a single switch activation will be ignored. Similarly the detecting circuit is arranged to ignore switch activation of multiple single switches. Furthermore activation of more than one pair of switches is also ignored.  
           [0010]    In accordance with the invention, two switches are located underneath the same operating area and are connected in series. Preferably a first end of the series connection is coupled to a first reference potential such as a ground and a second end is coupled to an input from the detecting circuit and to a second reference potential such as a operating voltage via a resistor. The detecting circuit is designed in such a way that only when the two switches are turned on at the same time the detecting circuit can detect that button is being pressed by the user.  
           [0011]    To select or navigate four exemplary functions A, B, C, D operating areas or sectors with associated switches are located with reference to compass positions North, South, East and West.  
           [0012]    In another embodiment of the invention the two key switches are arranged opposing each other referred to a center line which corresponds to the operating area.  
           [0013]    Advantageously the push-button is formed as a single-piece button with circular, rectangular or annular shape. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 shows a top plan view of a four-position selector switch push-button cover used in an inventive arrangement.  
         [0015]    [0015]FIG. 2 shows an inventive arrangement a four-position switch without push-button cover of FIG. 1.  
         [0016]    [0016]FIG. 3 shows a schematic drawing of an inventive detecting unit forming part of the inventive arrangement of FIGS. 1 and 2.  
         [0017]    [0017]FIG. 4 shows a perspective view of switching elements of the four-position switch on a motherboard forming part of the inventive arrangement of FIGS. 1 and 2. 
     
    
     DETAILED DESCRIPTION  
       [0018]    [0018]FIG. 1 shows a top plan view of the selector switch  10  designed as a four-position push-button selector switch as specified by the invention, including an operating element formed as a single-piece, round push-button  12 . Operating areas  14 ,  16 ,  18 ,  20  are disposed with compass positions North, South, East and West to enable selection of individual functions A, B, C or D of an electronic device such as a video recorder, a monitor or similar device.  
         [0019]    [0019]FIG. 2 shows a top plan view of the four-position switch  10  without push-button  12 . The four-position switch is designed in such a manner, that under each of the operating areas  14 ,  16 ,  18 ,  20  at least two, individual key or momentary action switches  22 ,  24 ;  26 ,  28 ;  30 ,  32 ; and  34 ,  36  are arranged, to prevent mistriggering. In the preferred embodiment the individual switches are each in a symmetrical arrangement about respective center lines  38 ,  40 ,  42 ,  44  of the operating segments.  
         [0020]    [0020]FIG. 3 is a simplified schematic drawing of a detector circuit for the selector switch  10  as shown in FIG. 2. This circuit arrangement shows key switches  22 ,  24 ;  26 ,  28 . A similar arrangement can be provided for switches  30 ,  32  and  34 ,  36 . The individual switches are grouped in pairs, for example  22 / 24  and  26 / 28 ,  30 / 32  and  34 / 36  with the individual switch pair connected in series and assigned respectively to operating areas  14 ,  16 ,  18 ,  20 . As an example, FIG. 3 shows a serial circuit  46  of the key switches  22 ,  24  as well as a serial circuit  48  of the key switches  26 ,  28 . The serial circuits are each connected to a first end  50 ,  52  with ground potential  54  and to a second end  56 ,  58  each with an input  60 ,  62  of an detecting unit  64 , which in the current example is provided as a microprocessor. The inputs  60 ,  62  are connected through respective resistors  66 ,  68  to an operating voltage (5V). When, for example, switches  22 ,  24  are activated concurrently the operating voltage provided to input  60  of microprocessor  64  via exemplary resistor  66  is replaced by ground potential  54 . Thus in response to exemplary input  60  assuming a ground potential microprocessor  64  controls activation of the user desired mode.  
         [0021]    The inventive detector  64  for the four-position switch  10  is characterized in that at the inputs  60  and  62  of the detecting unit  64 , a signal is only present if both the key switches  22 ,  24  under the operating segment  14  are pushed, i.e. are closed at the same time. If only one key switch is closed, an input signal is not recognized by detector  64 .  
         [0022]    If the push-button  12  is moved to the provided operating areas  14 ,  16 ,  18 ,  20 , the key switches arranged under each of the operating areas react so that a corresponding input signal is generated. If the operating button is pushed, for example, at a spot between North and East, closing individual key switches  24  and  26  of adjacent switch pairs, the detecting unit  64  receives no input signal. Thus, mistriggering is ruled out.  
         [0023]    In other words the detecting unit  64  only reacts if the key switches integral to one operating position are pressed together. In this way detector  64  ensures that control activation occurs when the switches of only one operating position are pressed together otherwise the action of pressing of the push-button  12  is ignored.  
         [0024]    [0024]FIG. 4 shows a perspective view of a motherboard  70 , on which the key switches  22 ,  24 ;  26 ,  28 ;  30 ,  32  as well as  34 ,  36  are arranged as specified by the invention. The individual key switches  22 ,  24  can also be designed in one piece as so-called dual-switch.  
         [0025]    [0025]FIG. 5 shows various views of the push-button  12 . The single-piece button  12  in a round design in the current example, can be made of metal or plastic.  
         [0026]    [0026]FIG. 5 a  shows an underside  72  of the button  12 . Operating elements  74 - 80  allocated to the key switches  22 ,  24 ;  26 ,  28 ;  30 ,  32  as well as  34 ,  36 , extend downwards substantially vertically to operate the key switches. Along the circumferential edge  82  of the push-button  12  locking elements  84 - 90  also extend downwards from the underside  72  which are provided to hold the push-button  12  in a housing of an electronic device (not shown). FIG. 5 b  shows a side view of the push-button  12 , in which the locking elements  84 - 90  are visible.  
         [0027]    [0027]FIG. 5 c  shows a top plan view of the push-button  12  and the operating segments  14 ,  16 ,  18 ,  20 . Here the operating areas  14 ,  16 ,  18 ,  20  are optically separated by the reference numbers  92 ,  94 , the reference number  92 , for example is designed as a protrusion and the reference number  94  as an indent, to optically distinguish the operating areas  14 ,  16 ,  18 ,  20  from each other.  
         [0028]    The inventive selector switch, described in the current example as four-position push-button selector switch, can of course also be designed as a multi-position switch. The advantageous use of at least two key switches positioned under one operating area, eliminates errors caused by inaccurate or mis-located button pressing. In addition this embodiment provides a simple and low-cost arrangement since no specialized electronic and mechanical elements are required.