Patent Publication Number: US-9418798-B2

Title: Keyboard

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a keyboard used for manipulating an electronic device. 
     2. Related Art 
     As is well known, keyboards, which have a number of keys arrayed on a baseplate, are commonly used as operational means for operating electronic devices such as so-called personal computers (properly abbreviated as “PC”, hereinafter) and information terminal devices, for example. In the conventional keyboards, adjacent keys are generally arrayed such that bottom ends of the sidewalls of the keys, which slant outward-downward from edges of top ends of keycaps, are lined with a predetermined clearance therebetween. In these cases, keyboards in which protecting sheets are deployed are known. This aims to prevent fluid or dust from breaking in through the clearances between keycaps of neighboring keys and the like (see JP 2011-187298 A, for example). 
     Further, so-called isolation keyboards (or called as island-type keyboards), in which adjacent keys are separated with frames such that the frames surrounds respective keys, have been adopted in some cases to achieve compactification and secure keystrokes as well as to enhance the sophistication in design, for example. 
     SUMMARY 
     In the above mentioned isolation keyboards, frames surrounding respective keys are normally arranged such that they stand approximately-perpendicularly to baseplates which support the keys. Clearances are arranged between the inner side faces of the frames and keycap sidewalls hanging down from the edges of the top ends of the keycaps. In such cases, the keycap sidewalls are normally formed such that they hang down from the edges of the top ends of the keycaps to the baseplate with an aim of compactification of the respective keys and securing excellence in keying operation. 
     In keyboards which are compactly manufactured to have slimline profile of the entire bodies, if the sidewalls of the keycaps are formed such that they hang down from the edge of the top ends of the keycaps to the baseplate as mentioned above, there may be cases where a tip of a finger of an operator (a user) who strokes a key get into the clearance between the keycap sidewalls and the inner side face of the frame. In these cases, if the tip hooks a bottom end face of the keycap sidewall, a force having a direction to exfoliate the keycap from the baseplate acts on the keycap. In this context, it may be thought that this issue can be avoided by designing the keycaps such that the bottom end faces of the keycap sidewalls take positions below the top end face of the frame in the situation where the keys are not depressed. 
     In the case where the keycap sidewalls are formed such that they hang down from the edges of the top ends of the keycaps to the baseplate, it is sometimes disadvantageous in securing an adequate depression-stroke (a keystroke) for depressing the keycap, that is, an interval which the keycap sidewall travels to touch the top face of the baseplate in the limited space within the key due to the compactification. This is more apparent in the case where the keycaps are designed such that the bottom end faces of the keycap sidewalls may take positions below the top end faces of the frames even when the keys are not depressed as mentioned above. 
     Accordingly, one non-limiting and exemplary embodiment provides a so-called isolation keyboard in which an adequate keystroke is secured even if the keycaps sidewalls are configured such that they hang down from the edges of the top ends of the keycaps to the baseplate. 
     For this, the present disclosure provides a keyboard: a) which includes a plurality of keys, a baseplate which supports each of the keys, and a frame which is arranged to stand substantially perpendicularly with respect to the baseplate and to surround the each of the keys; and b) in which the each of the keys includes an keycap configured to be depressed, the keycap including a keycap top end which constitutes a top end of the keycap and a keycap sidewall which hangs down from an edge of the keycap top end to the baseplate; and c) in which the baseplate has a hole arranged at a site that corresponds to a bottom end of the keycap sidewall, the hole configured to insert the bottom end of the keycap sidewall therein from above; and d) in which, when the keycap is in a depressed state at which the key is depressed, the bottom end of the keycap sidewall is inserted into the hole. 
     According to the keyboard of the present disclosure, the bottom end of the keycap sidewall is inserted into the hole of the baseplate in the depressed state of the keycap. Hence, the keystroke can be secured largely in accordance with an amount of the insertion. Accordingly, in the so-called isolation keyboard, an adequate keystroke can be secured even when the keycap sidewall is formed such that it hangs down from the edge of the keycap to the baseplate. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a full-perspective view illustrating a notebook-sized personal computer according to an exemplary embodiment of the present disclosure in an operational state; 
         FIG. 2  is a plan view of a keyboard of the notebook-sized personal computer; 
         FIG. 3  is an enlarged plan view illustrating a keycap and a frame of the keyboard; 
         FIG. 4  is an enlarged perspective view illustrating the keycap; 
         FIG. 5  is a vertical sectional view showing a cross sectional structure of the keyboard including the keycap and the frame; 
         FIG. 6  is an enlarged vertical sectional view showing a keycap sidewall and the frame in a situation where the keycap is not manipulated; and 
         FIG. 7  is an enlarged vertical sectional view showing the keycap sidewall and the frame in a situation where the keycap is depressed. 
     
    
    
     DETAILED DESCRIPTION 
     The configuration mentioned above is a basic configuration of an electronic device of the present disclosure. However, the electronic device may have several modes as illustrated below. This means that the keycap sidewall may be formed such that the bottom end face thereof takes a position below a top end face of the frame in a non-depressed state at which the keycap is not depressed. 
     By this configuration, the bottom end face of the keycap sidewall is positioned below the top end face of the frame even in a non-depressed state of the keycap. Hence, even when a tip of a finger of a user get into a clearance between the keycap sidewall and an inner side face of the frame while he/she typing the key, the tip is prevented from being hooked into the bottom end of the keycap sidewall. Therefore, occurrence of such the situation can be prevented. 
     In addition, as for a portion of the edge of the keycap top end, it may be configured as that the hang down length of the keycap sidewall hanging down from the portion is longer than a keycap sidewall hanging down from the other portion of the edge. The bottom end face of the keycap sidewall of which hang down length is configured to be longer may be positioned below the top end face of the frame in the non-depressed state at which the keycap is not depressed. The hole which corresponds to the down below of the keycap sidewall of which hang down length is configured to be longer may be arranged by penetrating the baseplate. 
     By this configuration, it never results in bad effect on securing the keystrokes since the portion of the keycap sidewall of which hang down length is configured to be longer is inserted into the hole which penetrates through the baseplate in the depressed state. Accordingly, it makes possible to configure the keycap sidewall such that the bottom end face of the keycap sidewall of which hang down length is configured to be longer can be positioned sufficiently below the top end face of the frame even in the non-depressed state without resulting in bad effect on the securing of the keystroke. Even if a tip of a finger of a user get into clearance between the keycap sidewall and an inner side face of the frame while typing, it effectively prevents the tips from being hooked into the bottom end face of the keycap sidewall. Therefore occurrence of such the situation can surely be prevented. 
     In this case, a detecting device which detects a depression of a keycap may be arranged under the keycap. A signal line which outputs an output signal from the detecting device may be wired such that it goes through a region which corresponds to the down below of the above mentioned other portion of the keycap sidewall of which hang down length is relatively short. 
     In this configuration, the signal line can be wired efficiently using the region under the portion of keycap sidewall of which hang down length is relatively short. 
     In the cases above mentioned, the keycap top end may be formed such that it can be seen as a tetragon from above. In the edges of the corner portions of the tetragon, the keycap sidewalls hanging down therefrom may be configured such that their hang down length be longer than the keycap sidewalls hanging down from the other edges. 
     By this configuration, as for the keycap of which keycap top end is configured as it can be seen as a tetragon from above, even in the case where a tip of a finger of a user get into the clearance between the keycap sidewall and the inner side face of the frame while typing, it can surely prevent the tip of the finger of the user from being hooked in the bottom end face of the keycap sidewall without resulting in bad effect on the ensuring of the keystrokes. In addition, signal lines can be wired by efficiently utilizing the downward regions under the side portions of the tetragon where the hang down lengths of the keycap sidewalls are relatively short. 
     (Embodiment) 
     Below, an exemplary embodiment is described in detail by appropriately making reference to drawings. However, unnecessarily detailed description will be omitted in some cases. For example, detailed description of already well-known matters and repetition of descriptions of substantially the same configuration may be omitted. All of such omissions are intended to facilitate the understanding by those skilled in the art by avoiding unnecessarily redundancy in the following description. 
     The inventor(s) provides the attached drawings and the following description for those skilled in the art to fully understand the present disclosure and does not intend to limit the subject matter stated in the claims by means of the attached drawings and the following description. 
     In the description below, terms which mean specific directions (“up”, “down”, “left”, and “right”, and other terms including such words, and “clockwise direction” and “counterclockwise direction”, for example) are used in some cases. However, they are used to facilitate the understanding of the disclosure which refers to the drawings. The present disclosure should not be understood in a limited fashion based on the meaning of those terms. 
     The embodiment of the present disclosure described below is an example, in which it is applied to a so-called notebook-sized personal computer. 
       FIG. 1  is a full-perspective view illustrating the notebook-sized personal computer in an operational state which serves as an electronic device according to the exemplary embodiment.  FIG. 2  is a plan view of the keyboard of the notebook-sized personal computer. 
     As shown in  FIG. 1 , the notebook-sized personal computer W according to the present embodiment includes a display unit  11  having a display screen  15  of a liquid crystal type and an operational control unit  20  which is capable of generating a display signal to be inputted to the display unit  10 , for example. The operational control unit  20  includes a keyboard  30  serving as an input device, a signal processing circuit or a central processing unit (a so-called CPU), which generates a display signal to be outputted to the display unit  10  based on input operations by means of the keyboard  30  or the like, and another peripheral components thereof. (They all are not shown). Furthermore, a palm rest  25  on which a user may put his/her palms of the hands is arranged in the near side of the keyboard  30  from the user who operates the notebook-sized personal computer W. In the central region of the palm rest  25 , a touch-pad  26  is disposed. 
     The display unit  10  is built into a casing  11  of a display unit side (a first casing), which covers the rear side and the edges of the display unit  10 . As for the operational control unit  20 , it is built into another casing  21  of an operational control unit side (a second casing). The casings  11 ,  21  are openably and closably conjoined with hinge mechanisms  3 . Total basic forms of both of the first casing  11  and the second casing  21  are formed in approximate rectangular shapes. It is to be noted that, in the present description, the “rectangle” includes a “regular square” as one form thereof. 
     As also shown in  FIG. 2 , the keyboard  30  includes a number of keys  31 . In the present embodiment, the keyboard  30  is configured as a so-called isolation keyboard (or called as an island-type keyboard), in which adjacent keys  31  are separated by a frame  41  so that the frame surrounds respective keys  31 . 
     As illustrated in  FIG. 5 , respective keys  31  are supported on a thin-plate base member  38  made of a metallic thin plate, for example. In detail further, as depicted in  FIG. 6  and  FIG. 7 , a so-called flexible printed circuit board  45  (FPC board), which of itself has a high flexibility, and a membrane sheet  46  are arranged on the thin-plate base member  38  in this order, for example. To be exact, respective keys  31  are supported on the thin-plate base member  38  via the FPC board  45  and the membrane sheet  46 . 
     Although not shown in the figures specifically, it is to be noted that a number of integrally-formed projections are provided on the bottom face of the membrane sheet  46 , and a number of holes are correspondingly provided on the thin-plate base member  38 . The numerous projections are fitted and fixed in the numerous holes of the thin-plate base member  38  with the FPC board sandwiched between the membrane sheet  46  and the thin-plate base member  38 , and, thereby, the membrane sheet  46 , the FPC board  45 , and the thin-plate base member  38  are integrated with each other. 
     In the present embodiment, the thing which is formed by integrating the thin-plate base member  38 , the FPC board  45  and the membrane sheet  46  integrally arranged on the thin-plate base member  38  is referred to as a baseplate  39 . Accordingly, respective keys  31  are supported on the baseplate  39 , and the frame  41  is arranged so as to stand approximately perpendicularly to the baseplate  39  and surround the respective keys  31 . In the present embodiment, the thickness T of the baseplate  39  is 0.5 mm, for example. It is to be noted that, in  FIG. 5 , the thin-plate base member  38 , the FPC board  45 , and the membrane sheet  46  are not separately depicted to prevent the depiction from being excessively minute and complicated. 
     In addition, each of the keys  31  has a keycap  32  which can be depressed by a user. The keycap  32  includes a keycap top end  33  which constitutes a top end of the keycap  32  and a keycap sidewall  34  which hangs down from an edge of the keycap top end  33  substantially perpendicularly to the baseplate  39  as shown in detail in  FIG. 3  and  FIG. 4 . 
     The keycaps  32  of respective keys  31  are elevatably supported on the baseplate  39  via pantograph mechanisms  35  and rubber springs  36 . A projected portion  36   p  projecting downwardly is integrally formed at the center of the rubber spring  36 . The projected portion  36   p  faces a membrane switch  46   s  arranged on the membrane sheet in a non-operation state where the keycap  32  is not depressed. 
     When the keycap  32  is depressed by a user while he/she typing the keys, the pantograph mechanism  35  and the rubber spring  36  performs a downward contraction operation. Accordingly, the projected portion  36   p  of the rubber spring  36  pushes the membrane switch  46   s . Although not shown in the figure specifically, the membrane switch  46   s  has a contact portion and the contact portion includes a movable contact and a fixed contact. The movable contact makes contact with the fixed contact and they are electrically closed when the movable contact is pushed by the projected portion  36   p  of the rubber spring  36 . The membrane switch  46   s  detects the depression of the keycap  32  by the electrical closure. A detection signal is outputted through a signal line wired on the flexible printed circuit board (FPC board)  45 . Necessitated operation in the personal computer W is performed in accordance with the output signal. 
     When the depression of the keycap  32  by the user is released, the contact portion of the membrane switch  46   s  is opened and the pantograph mechanism  35  expands upward due to the elastic reaction force of the rubber spring  36 . 
     Thereby, the keycap  32  returns to its initial position (non-operation position). It is to be noted that the elevation mechanism for the keycap  32  including the pantograph mechanism  35 , the rubber spring  36 , and the membrane sheet  46  is similar to those that have already known to the public. For example, the elevation mechanism disclosed in JP 2011-187298 A may be used. 
     In the present embodiment, as shown in  FIG. 6  and  FIG. 7 , a hole  39   h  into which the bottom end of the keycap sidewall  34  can be inserted from above is arranged at a site of the baseplate  39  that corresponds to the bottom end of the keycap sidewall  34 . When the key is in a depressed state at which the keycap  32  is depressed, the bottom end of the keycap sidewall  34  is inserted into the hole  39   h  of the baseplate  39 . 
     As described, the bottom end of the keycap sidewall  34  is inserted into the hole  39   h  of the baseplate  39  at the depressed state of the keycap  32 . Hence, the keystroke thereof can be largely secured in accordance with an amount of the insertion. Accordingly, in the so-called isolation keyboard, an adequate keystroke can be secured even when the keycap sidewall  34  is formed such that it hangs down from the edge of the keycap  32  to the baseplate  39 . 
     Furthermore, in the case mentioned above, as shown in  FIG. 6 , the keycap sidewall  34  is formed such that the bottom end face thereof takes a position below the top end face of the frame  41  in a non-depressed state at which the keycap  32  is not depressed. In this case, the bottom end face of the keycap sidewall  34  is positioned below the top end face of the frame  41  even in the non-depressed state of the keycap  32 . Even if a tip of a finger of a user get into clearance between the keycap sidewall  34  and an inner side face of the frame  41  while he/she typing the key, it prevents the tip from being hooked into the bottom end of the keycap sidewall  34 . Therefore, occurrence of such the situation can be prevented. 
     In detail, in the present embodiment, the keycap top end  33  is formed such that it can be seen as a tetragon from above (see  FIG. 3  and  FIG. 4 ). In the edges of the corner portions  33   a  of the tetragon, the keycap sidewall  34  hanging down therefrom may be configured such that their hang down length L 2  be longer than the hang down length L 1  of the keycap sidewall  34  which hang down from the other edges  33   b  (that is, side portions of the tetragon). In the present embodiment, the hang down length L 2  which is the length of the keycap sidewall  34  hanging down from the edges of the corner portions  33   a  of the tetragon is 1.4 mm, for example, and the hang down length L 1  which is the length of the keycap sidewall  34  hanging down from the side portions  33   b  of the tetragon is 1.0 mm, for example. 
     In short, as for the portion  33   a  of the edge of the keycap top end  33 , it is configured as that the hang down length L 2  of the keycap sidewall  34  hanging down from the portion  33   a  is longer than the hang down length L 1  of the keycap sidewall  34  hanging down from the other portion  33   b  of the edge. As shown in  FIG. 6 , the bottom end face of the keycap sidewall  34  of which hang down length is configured to be longer (L 2 ) is positioned below the top end face of the frame  41  by E mm (approximately 0.5 mm in the present embodiment) in the non-depressed state at which the keycap is not depressed. The hole  39   h  of the baseplate  39 , which corresponds to the down below of the keycap sidewall  34  of which hang down length is configured to be longer, is arranged by penetrating the baseplate. 
     By this configuration, it never results in bad effect on securing the keystrokes since the portion of the keycap sidewall  34  of which hang down length is configured to be longer is inserted into the hole  39   h  which penetrates through the baseplate  39  in the depressed state. In other words, it makes possible to configure the keycap sidewall such that the bottom end face of the keycap sidewall  34  of which hang down length is configured to be longer (L 2 ) can be positioned sufficiently below the top end face of the frame  41  even in the non-depressed state without resulting in bad effect on securing the keystroke. Even if the tip of the finger of the user get into clearance Gp between the keycap sidewall  34  and an inner side face of the frame  41  while typing, it effectively prevents the tip from being hooked into the bottom end face of the keycap sidewall  34 . 
     Therefore occurrence of such the situation can surely be prevented. 
     In the present embodiment, the pantograph mechanism  35 , the rubber spring  36  with the projected portion  36   p , the membrane sheet  46 , and the membrane switch  46   s  are disposed underneath the keycap  32  as the detecting device which detects the depression of the keycap  32 . The FPC board  45  on which the signal line which outputs an output signal from the detecting device is wired is disposed extending through the region which corresponds to the down below of the keycap sidewall  34  of which hang down length (L 1 ) of the keycap sidewall  34  hanging down from the edge of the keycap top end  33  is configured to be shorter as compared to the hang down length (L 2 ) of the keycap sidewall  34  hanging down from the edge of the corner portion  33   a  of the tetragon (that is, the region beneath the side portion  33   b  of the tetragon) (see  FIG. 4 ). 
     Accordingly, especially as for the keycap  32  of which keycap top end  33  is configured as it can be seen as a tetragon from above, even in the case where the tip of the finger of the user get into the clearance between the keycap sidewall  34  and the inner side face of the frame  41  while typing, it can surely prevent the tip of the finger of the user from being hooked in the bottom end face of the keycap sidewall  34  without resulting in bad effect on the ensuring of the keystrokes. In addition, signal lines can be wired efficiently utilizing the downward regions underneath the side portions  33   b  of the tetragon where the hang down lengths (L 1 ) of the keycap sidewalls  34  are relatively short. 
     As described, the embodiment is explained as an example of the art of the present disclosure. For that purpose, the accompanying drawings and detailed description are provided. Therefore, the feature constituents described in the detailed description and the accompanying drawings may contain not only essential feature constituents for solving the problem but non-essential feature constituents for illustrating the art. Accordingly, it should not be instantly understood that such the non-essential constituents are essential simply because those non-essential constituents are shown or described in the accompanying drawings and the detailed description. 
     The embodiment above is illustrated using an example where it is applied to a so-called notebook-sized personal computer. The keyboard of the present disclosure should not be limited in such the case. It can be effectively applied to a keyboard used for various types of electronic devices. 
     Also, since the above described embodiment is provided for exemplifying the art of the present disclosure, the embodiment may be subjected to various kinds of modification, substitution, addition, omission, or the like without departing from the scope of the claims and their equivalents. 
     The present disclosure is effectively applicable to a keyboard used for manipulating an electronic device such as a notebook-sized personal computer and an information terminal device.