Abstract:
A key assembly which is configured to provide improved click feeling to a user and an electronic device having the same are provided. The key assembly includes a key body of elastic materials and contact projections, each of the contact projections which is protruded and formed from the key body and presses a switch device spaced apart from the key body by a gap providing a certain interval, wherein the key body is installed such that a contact surface of each of the contact projections is in contact with and pushed back by a certain distance by a pre-loading force of the switch device.

Description:
CLAIM OF PRIORITY 
     This application claims the benefit under 35 U.S.C. §119(a) from a patent applications filed in the Chinese Patent Office on Jun. 26, 2012 and assigned Serial No. 201220303763.X and filed in the Korean Intellectual Property Office on May 28, 2013 and assigned Serial No. 10-2013-0060224, the entire disclosure of which is hereby incorporated by reference in its entirety. 
     BACKGROUND 
     1. Field of the Invention 
     The present disclosure relates to a key assembly. More particularly, the present invention relates to a key assembly which is configured to provide improved click feeling and tactile sensation to a user and an electronic device having the same. 
     2. Description of the Related Art 
     In general, each of electronic devices such as a mobile phone, a Moving Picture Experts Group (MPEG) audio layer 3 (MP3) player, a tablet Personal Computer (PC) has a key assembly to enable quick and precise control a user wants. 
     For example, a side key in the key assembly may be divided into two types according to a type of a switch installed on a Printed Board Assembly (PBA). One of the two types is a Flexible Printed Circuit Board (FPCB) type, and the other of them is a tactile or tact switch type. 
     A switch of the FPCB type does not provide the user with excellent performance with respect to click feeling or tactile response. However, when adopting the switch of the FPCB type, it is necessary to perform a soldering process of soldering the switch of the FPCB to the PBA. Also, because an FPCB itself is relatively expensive, it is common for standard or ordinary devices to adopt the tact switch type. Some cutting edge devices however may adopt the use of the FPCB switch. 
     However, while in case of a tact switch, has the benefit of being relatively inexpensive, a side key assembly adopting this tact switch can have other problems. The use of a tact switch can cause a result in which there are problems such as a vibration noise and deterioration in click feeling due to the accumulation of various tolerances such as a tolerance of a Surface Mounted Device (SMD) of the PBA and an injection molding tolerance of a side key formed by an injection molding type. 
     In order to improve a vibration noise and click feeling of the side key assembly adopting the tact switch, injection molding processes and methods must be continuously adjusted. This results in the increase of research and development costs and nonetheless does not provide an ideal solution for an effect for improving the vibration noise and click feeling. In addition, when installing additional portions and components to improve click feeling, space utilization of the side key assembly may deteriorate. 
     SUMMARY 
     An exemplary aspect of the present invention is to solve at least some of the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an exemplary aspect of the present invention is to provide a key assembly for removing a vibration noise and improving click feeling and tactile response and an electronic device having the same. 
     Another exemplary aspect of the present invention is to provide a key assembly for simultaneously improving click feeling and tactile response of an electronic device, reducing its costs, and enhancing its space utilization and an electronic device having the same. 
     In accordance with an exemplary aspect of the present invention, an electronic device includes a key assembly disposed such that a part thereof is extending into and exposed within the interior of the electronic device; and a switch device disposed within the interior of the electronic device to perform an electric switching operation in response to a force exerted on the key assembly, wherein the key assembly includes a key body of resilient elastic materials and contact projections, each of the contact projections which is protruded and formed in a direction extending from the key body towards the switch device and wherein the key body is installed such that a contact surface of each of the contact projections is in contact with the switch device and wherein each of the contact projections is pushed back and elastically deformed by a certain predetermined distance by the switch device. 
     In accordance with another exemplary aspect of the present invention, a key assembly includes: a key body of elastic materials; and contact projections formed in the key body wherein each of the contact projections protrudes from the key body for pressing a switch device which is installed and spaced apart from the key body at a certain interval, wherein the key body is installed such that a contact surface of each of the contact projections is in contact with and is pushed back by a certain distance by a force exerted by the switch device. 
     In accordance with another exemplary aspect of the present invention, an electronic device includes: a key assembly disposed such that a part thereof is extending into and exposed within the interior of the electronic device; and a tact switch disposed in the electronic device in alignment with the key assembly to perform an electric switching operation in response to a force exerted on the key assembly, wherein the key assembly includes a key case installed to be exposed to the outside of the electronic device, a key body of elastic materials which is combined and fixed with the key case, wherein the key case is attached to an outer surface of the key body and adapted to receive and support the key body, the key case being comprised of contact projections, each of the contact projections, having an inner hollow cavity, wherein each of the contact projections is protruded and formed in a direction from the key body and extending toward the tact switch, a push projection which is formed within the hollow cavity and is formed to be protruded on a surface of the key body in a direction toward the switch device wherein the hollow cavity provides a predetermined gap between the push projection and an inner wall of the contact projections; and one or more concave groove portions formed surrounding each of the contact projections of the key body to provide enhanced elasticity of each of the contact projections and wherein the key body is installed such that a contact surface of each of the contact projections is in contact with and pushed back by a certain distance by a force exerted by a contact head of the tact switch. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other exemplary aspects, features and advantages of certain exemplary embodiments of the KEY ASSEMBLY AND ELECTRONIC DEVICE HAVING THE SAME according to the present invention will become more apparent to a person of ordinary skill in the art from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  illustrates an exemplary structure of a side key in a key assembly according to an embodiment of the present invention; 
         FIG. 2  illustrates an exemplary lower surface structure of a contact projection of  FIG. 1  according to an embodiment of the present invention; 
         FIG. 3  illustrates an exemplary cross sectional view taken from a line A-A of  FIG. 2  according to an embodiment of the present invention; and 
         FIG. 4  illustrates an exemplary combination state structure of a key assembly according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments of the present invention will now be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions may not be described in detail when they would obscure appreciation of the present invention by a person of ordinary skill in the art with unnecessary detail of the well-known functions and structures. Also, the terms used herein are defined according to the functions of the present invention as would be understood by a person of ordinary skill in the art. Thus, the terms may vary depending on user&#39;s or operator&#39;s intension and usage. That is, the terms used herein must be understood based on the descriptions made herein in view of the ordinary level of skill in the art. 
     In describing various embodiments of the present invention, an electronic device may be at least one of various electronic devices, each of them which has a key assembly capable of performing a physical key button operation. The electronic device may be any one of a Personal Digital Assistant (PDA), a laptop computer, a mobile phone, a smart phone, a netbook, a Mobile Internet Device (MID), a Ultra Mobile PC (UMPC), a tablet PC, a navigation device, and an MP3 player. 
     Hereinafter, a description will be given with reference to, but is not limited to, a side key which is installed at a side of the electronic device. For example, the electronic device may adopt a physical key assembly, for performing various functions, which is disposed such that a part of the physical key assembly is exposed to the outside of the electronic device to adjust a tact switch installed in the electronic device. 
       FIG. 1  illustrates a structure of a side key in a key assembly according to one exemplary embodiment of the present invention.  FIG. 2  illustrates a lower surface structure of a contact projection depicted in  FIG. 1  according to one exemplary embodiment of the present invention.  FIG. 3  illustrates a cross sectional view taken from a line A-A of  FIG. 2  according to one exemplary embodiment of the present invention.  FIG. 4  illustrates a combination state structure of a key assembly according to one embodiment of the present invention. 
     Referring to  FIGS. 1 to 4 , the side key denoted by  100  may include a key case  101  and a key body  102 . The key case  101  is formed of plastic or resin through an injection molding type process. For example, the key body  102  may be formed of resin such as urethane and silicon or other elastic and resilient materials such as rubber. Therefore, materials of the key case  101  may be provided to be hard relatively as compared to key body  102 . Materials of the key body  102  may be provided to be soft relatively. The key case  101  and the key body  102  may be coupled by, but is not limited to, an adhesive. Also, the key case  101  and the key body  102  may be coupled through alternate methods such as a well-known ultrasonic fusion method and a well-known insert molding method. 
     In order to enhance combining force between the key case  101  and the key body  102 , a plurality of combining projections  109  may be formed on an inner surface of the key case  101 . Complementary to the plurality of combining projections  109 , a plurality of fixed concave groove parts  110  may be formed in an upper surface of the key body  102  for receiving the combining projections  109  in alignment with the combining projections  109 . Accordingly, inserting the plurality of combining projections  109  of the key case  101  into the plurality of fixed concave groove parts of the key body  102  may help to enhance combining force between the key case  101  and the key body  102  by providing an increased area of contact between the key case  101  and the key body  102 . In addition there is a provided a close interference fit between the combining projections and the combining groove parts. In accordance with one embodiment of the present invention, a fixing part  111  may be integrated with both sides of the key body  102  to mount and fix the side key  100  on a certain portion of an electronic device. In accordance with one embodiment of the present invention, several convex edges  113  may be formed on other portions except for both the sides in the key body  102  to fix and install the side key  100 . In accordance with one embodiment of the present invention, contact projections  103  which are projected toward a lower side of the side key  100  in a direction to come in contact with a tact switch  105  (see  FIG. 4 ) that is disposed in the electronic device in response to a lower side of the side key  100  may be formed on lower certain positions of the side key  100 . The same elastic materials as the key body  102  may be adopted in each of the contact projections  103 . In accordance with one embodiment of the present invention, the contact projections  103  may be integrated with the key body  102 . 
     The tact switch  105  may be mounted on one side of a PBA of the electronic device. The tact switch  105  may be directly mounted on the PBA through a surface mount device (SMD) soldering process. Accordingly, a single soldering process may be omitted in comparison with a switch of an FPCB type. In accordance with one embodiment of the present invention, the tact switch  105  has at least one contact head  106 . When the contact head  106  is pushed, the tact switch  105  is electrically connected to execute a corresponding function. 
     Referring to  FIG. 4 , a contact surface of each of the contact projections  103  is pushed to a certain distance by the contact head  106  of the tact switch  105 . In accordance with one embodiment of the present invention, a vibration noise (pushing noise) generated by accumulation tolerance in the components such as injection molding tolerance of the side key  100  and mounting tolerance of the tact switch  105  may be improved and click feeling may be improved by pushing the contact projections  103  to the certain distance by the contact head  106  and thereby minimizing the effects of the accumulation tolerance. 
     A reference numeral B shown in  FIG. 4  indicates a side structure of each of the contact projections  103 . In accordance with one embodiment of the present invention, the side structure may save a space of the side key  100  by forming a “C”-type cross section. 
     Referring to  FIGS. 1 and 2  again, a hollow cavity  107  (see  FIG. 3 ) may be formed in each of the contact projections  103 . In accordance with one exemplary embodiment of the present invention, the cavity  107  may be formed in each of the contact projections  103 . Preferably, an opening  112  (see  FIG. 4 ) may be formed in one side of each of the contact projections  103 . The opening  112  provides greater flexibility of the contact projections  103 , thus allowing for greater movement of the contact projections  103  in response to pressure provided by the contact head  106 . 
     In accordance with one exemplary embodiment of the present invention, concave groove portions  108  are formed around a portion where each of the contact projections  103  of a lower surface of the side key  100  is formed to reinforce an elastic deformation effect of the contact projections  103  by allowing for greater flexing of the contact projections  103  around the base of the contact projections, thus allowing for greater movement of the contact projection in response to pressure provided by the contact head  106 . 
     In accordance with one exemplary embodiment of the present invention, a push projection  104  may be projected and formed from a lower surface of the key body  102  on the cavity  107  of each of the contact projections  103 . The push projection  104  may have a structure in which it is faced with pressure provided by the contact head  106  of the tact switch  105 . 
     Referring to  FIG. 3 , a reference numeral F denotes a certain interval between the push projection  104  and an inner surface of the cavity  107  which is faced with the push projection  104 , after the side key  100  is installed. In accordance with one embodiment of the present invention, the certain interval F may be 0.1 mm. 
     In accordance with one embodiment of the present invention, a push distance to which the contact head  106  pushes the contact surface of each of the contact projections  103  and a wall thickness of each of the contact projections  103  may be the same with each other. In other words, in one embodiment of the present invention, the interval F may be the same as the thickness of the wall of contact projections  103 . 
     In accordance with one embodiment of the present invention, when the key body  102  is manufactured by utilizing urethane, a wall thickness of each of the contact projections  103  may be set to 0.3 mm. Herein, an interval between the push projection  104  and an outer surface of the cavity  107  which is faced with the push projection  104  may be set to 0.4 mm. Accordingly, after installation of the side key  100  is completed, the contact head  106  pushes the contact surface of each of the contact projections  103  upwardly. For this reason, a side wall of each of the contact projections  103  which are formed of elastic materials is pre-loaded by the force of the contact head  106  bearing against the contact surface of each of the contact projections and is thus elastically deformed. Herein, the concave groove portions  108  are formed around each of the contact projections  103  of the lower surface of the key body  102 . Accordingly, elastic deformation efficiency of the side wall of each of the contact projections  103  may be more enhanced due to the groove portions  108  allowing greater movement of the side wall of each of the contact projections. Thus in this particular embodiment, the interval between the push projection  104  and the inner surface of the cavity  107  which is faced with the push projection  104  may be set at 0.1 mm. 
     In accordance with one embodiment of the present invention, click feeling and a vibration noise of the side key  100  may be improved by adjusting the certain interval between the push projection  104  and the inner surface of the cavity  107  which is faced with the push projection  104 . In accordance with one embodiment of the present invention, although tolerance on the side key  100  or the tact switch  105  is generated, a vibration noise (pushing noise) may be clearly improved according to the above-described contact type between the contact head  106  and each of the contact projections  103 . The interval may be as small as possible and also, the interval may be varied according to material of the key body  102 . 
     In accordance with various embodiments of the present invention, the key assembly and the electronic device having the same may remove a vibration noise considerably, improve click feeling, reduce its costs, enhance its space utilization, and improve key movement by external force in a set state. 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.