1. Field of the Invention
The present invention relates to keypads, and more particularly to a keypad structure for inputting signals into electronic devices including but not limited to those having vibration motors.
2. Background of the Related Art
As shown in the enlarged view of
The side buttons operate by activating a tact switch 12. As shown, a nose 13 of the tact switch contacts the bottom portion of the side button protruding inward into the case so as to support the side button 8. At another end, the tact switch is attached to a printed-circuit board 14 installed inside the case, so as to adhere closely to a rear face of the keypad. In operation, pressure is applied to nose 13 of the tact switch when a user presses a side button. A tact switch signal is then transferred to the printed-circuit board 14 in order to adjust the volume of the speaker phone.
This related-art terminal has a number of drawbacks. For example, a stroke of the nose of the tact switch is usually only 0.2 mm. If an assembly tolerance is +0.2 mm at a place where the side button is coupled with the case, then when the terminal is assembled the side button may push against a predetermined portion of the tact switch. As a result, the on/off operation of the tact switch 12 may be lost or at least adversely affected.
In order to overcome such a disadvantage, it has been proposed to couple the assembly of the side button with the case in such a maimer that one face of the keypad is just in contact with the nose of the tact switch. While this approach may have some limited success, it is complicated to perform and thus significantly increases the assembly time of the terminal.
This modification of the related art also has drawbacks. In this arrangement, the side button is not fixed to the side button hole 11, but rather is merely inserted into the side button hole for assembly. As a result, the side button may float and thus may be affected by a vibration motor which is activated in the terminal when a call is received. More specifically, the side button may collide with the nose of the tact switch when the variation motor is activated, thereby producing an undesirable noise. Moreover, if the interval between the bottom 15 of the side button and the nose 13 of the tact switch becomes greater than −0.2 mm by the assembly tolerance, the tact switch may fail to smoothly operate when the side button is pushed.
A need therefore exists for a terminal which demonstrates improved resistance to vibration compared with related-art terminals, while at the same time prevents malfunctions from occurring as a result of inaccurate assembly tolerances relating to one or more function keys on the terminal.
An object of the present invention is to provide an input device having at least one function key which overcomes one or more of the drawbacks of related art input devices.
Another object of the present invention is to provide an input device which demonstrates improved resistance to vibration.
Another object of the present invention is to provide an input device having at least one function key which prevents malfunctions from occurring as a result of inaccurate assembly tolerances.
Another object of the present invention is to provide an input device which simultaneously achieves both of the aforementioned objects.
Another object of the present invention is to provide a keypad which achieves any one or more of the aforementioned objects.
Another object of the present invention is to provide an electronic device which includes an input device which achieves any one or more of the aforementioned objects.
Another object of the present invention is to provide a mobile communications terminal having an input device which achieves any one or more of the aforementioned objects.
Another object of the present invention is to provide a mobile communications terminal which demonstrates improved resistance to vibration by eliminating clearance gaps between one or more function keys of the terminal and their corresponding switches. By achieving this object, the further object of reducing an undesirable noise is achieve as a result of the key rattling against either the terminal housing or switch when vibration is applied.
Another object of the present invention is to provide a mobile communications terminal wherein a tact switch for a function key smoothly operates according to push operation of the side button when a clearance gap between a nose of the tact switch and a bottom of the side button becomes wide open by an assembly tolerance.
To achieve these and other objects and advantages, the present invention provides a mobile communication terminal which includes a keypad installed in a case so that tops of key buttons formed on a front face protrude through key button holes formed in a front part of the case, at least one side button having a top protruding outside onside of the case and a bottom protruding inside the case so as to be inserted in a side button hole, a printed-circuit board having one end of a tact switch attached thereto so that the bottom of the side button confronts a nose of the tact switch with a predetermined interval, the printed-circuit board adhering closely to a rear side of the keypad so as to be installed inside the case, a side button vibration-preventing device in the mobile communication terminal according to the present invention is characterized in that the an elastic member is inserted between the bottom of the side button and the nose of the tact switch.
In another aspect of the present invention, a side button switch in a mobile communication terminal includes a switch button having a top penetrating a key button hole formed in a case of the mobile communication terminal and a bottom failing to penetrate the key button hole, an elastic member adhering closely to the bottom of the switch button, and a tact switch carrying out a switch operation by a force generated from the elastic member interoperating with the switch button pushed inside the case wherein the side button is a switch connected to an electronic circuit inside the mobile communication terminal.
The present invention is a function key switch which includes a button (or functions key) having a top which may protrude through a key hole formed in a case of an electronic device. In order to reduce or eliminate a clearance gap between the button and a corresponding switch, a spacer is positioned between the button and switch. If desired, the spacer may be adhered to either a bottom of the button or an end of the switch. The spacer may be made from an elastic or rigid material depending upon the application, and the switch may be a tact switch which carries out a switch operation in response to a force applied by the button when pushed by a user's finger. Other types of switches may be used if desired. The present invention is also a keypad incorporating the function key switch, as well as an electronic device incorporating either the function key switch alone or the keypad. The electronic device may be a mobile communications terminal or any other type of device which includes or otherwise operates using at least one function key. For illustrative purposes, the following embodiments are discussed in the context of a mobile terminal.
The elastic member 130 is inserted between the bottom of the side button and the nose of the tact switch. Nose 122 of the tact switch may therefore be used to support the bottom of the side button with the elastic member 130 positioned therebetween. The elastic member 130 may be formed from a variety of materials including soft rubber or silicon in order to provide cushion.
In the above-assembled present invention, nose 222 of the tact switch preferably supports the bottom of the side button and the spacer preferably has a thickness which leaves no gap between the switch and button. The side button 210 therefore does not move freely even if the terminal 250 vibrates by an external force or a vibration motor (not shown in the drawing) installed in the terminal 250. If desired, the spacer may have a thickness which is less than the clearance gap between the switch and button. Furthermore, as in all embodiments described herein, the spacer may be made from an elastic or rigid material.
Also, in any of the foregoing embodiments the spacer of the present invention, illustratively shown by elastic member 230 in
Accordingly, the present invention fills the gap between a button and a tact switch with a spacer which may be an elastic member. This spacer provides an excellent cushion for button pushing and also prevents the button from moving freely and making noise when vibration is applied, such as when a vibration motor of a mobile terminal is activated. Moreover, feeling of use is improved when the button is pressed as a result of the reduction or elimination of the clearance gap and/or the cushion provided by the spacer.
The foregoing embodiments are merely exemplary and are not to be construed as limiting the present invention. The present teachings can be readily applied to other types of apparatuses. Also, the description of the present invention is intended to be merely illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.
For example, while the embodiments of the invention have been described as providing a cushion for and reducing a clearance between a side button and a terminal casing, those skilled in the art can appreciate that the elastic members of the present invention may be used to cushion top surface buttons or any other button of a communications terminal, including not only hand sets but also PDAs, computers, or other types of electronic devices. Also, whole members 130 and 230 have been described as having elastic properties, these members may alternatively be made rigid materials if desired.
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10-2002-0048071 | Aug 2002 | KR | national |
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