Patent Publication Number: US-7902473-B2

Title: Key switch with exhaust structure

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the right of priority based on Taiwan Patent Application No. 95220661 entitled “Key with Exhaust Structure,” filed on Nov. 23, 2006, which is incorporated herein by reference and assigned to the assignee herein. 
     FIELD OF THE INVENTION 
     This invention relates to a key switch with an exhaust structure, and more particularly, relates to a key switch with an exhaust structure which is coupled with an elastic member having a gas channel, so that when an external force is applied to the keycap to compress the elastic member, the gas within the elastic member is exhausted through the gas channel or the exhaust structure. 
     BACKGROUND OF THE INVENTION 
     Following the fast development of high technology, computers have become more and more important in our daily life. Therefore, using a keyboard for data entry has become a part of routine works in our daily life. When users press the key switch, the keycap is closely attached to the rubber dome and the gas within the rubber dome is exhausted. However, a vacuum may be produced within the key switch, and in turn, the movement of the key switch will be affected. Thus, it is desired to provide a key switch with an exhaust structure so that the gas within the keyboard can exhaust freely and the formation of the vacuum can be effectively eliminated during the operation of the keyboard. 
     SUMMARY OF THE INVENTION 
     One object of the present invention is to provide a key switch, which includes a keycap having an inner surface with a cavity. The cavity can be a gas channel for exhausting gas within an elastic member when the elastic member is coupled with the inner surface of the keycap. 
     Another object of the present invention is to provide a key switch including an elastic member having a protrusion with at least one notch at its top end. When the protrusion is coupled with the inner surface of the keycap, a gas channel can be formed, and therefore, when an external force is applied to the keycap to compress the elastic member, the gas within the elastic member can be exhausted through the notch. 
     Still another object of the present invention is to provide a key switch including an elastic member having a protrusion with at least one aperture in its sidewall serving as a gas channel. When a keycap is coupled with the elastic member and an external force is applied to the keycap to compress the elastic member, the gas within the elastic member can be exhausted through the aperture. 
     In one preferable embodiment, the present invention provides a key switch with an exhaust structure. The key switch includes a keycap having a top surface and an inner surface; and an elastic member having a protrusion and an elastic body, a top end of the protrusion having at least one notch, the protrusion being coupled with the inner surface of the keycap, so that a gas channel is formed between the keycap and the elastic member. When an external force is applied to the top surface of the keycap to compress the elastic body, the gas within the elastic member is exhausted through the gas channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a top view of the keycap in accordance with one embodiment of the present invention; 
         FIG. 1B  is a bottom view of the keycap in accordance with one embodiment of the present invention; 
         FIG. 1C  is a schematic illustration of an inner surface with a cavity having a circular shape with an extended groove of the keycap in accordance with another embodiment of the present invention; 
         FIG. 1D  is a schematic illustration of an inner surface with a cavity having an radiant shape of the keycap in accordance with another embodiment of the present invention; 
         FIG. 1E  is a schematic illustration of an inner surface with a cavity having a rectangular shape of the keycap in accordance with another embodiment of the present invention; 
         FIG. 1F  is a schematic illustration of an inner surface with a cavity having a rectangular shape with at least two extended grooves of the keycap in accordance with a modified embodiment of the present invention; 
         FIG. 2A  is a side view of an elastic member in accordance with an embodiment of the present invention; 
         FIG. 2B  is a side view of an elastic member having gas channels in accordance with another embodiment of the present invention; 
         FIG. 2C  is a side view of an protrusion of the elastic member having at least one notch and at least one aperture in its top end and sidewall in accordance with a modified embodiment of the present invention; 
         FIG. 3A  and  FIG. 3B  show schematic views of the keycap without the cavity coupled with the elastic member with the notches in accordance with an embodiment of the present invention; 
         FIG. 4A  and  FIG. 4B  show schematic views of the keycap with a cavity coupled with the elastic member without the notch in accordance with another embodiment of the present invention; and 
         FIG. 5A  and  FIG. 5B  show schematic views of the keycap with a cavity coupled with the elastic member with the notches in accordance with another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The preferable embodiments of the present invention are discussed in detail hereinafter. However, it is understood that the invention can have variations and modifications in other embodiments without departing from the scope, and the invention is not to be limited to the details given herein. 
       FIG. 1A  to  FIG. 1F  are schematic views of various keycaps, which may or may not have a cavity of different shape.  FIG. 2A  to  FIG. 2C  are schematic views of various elastic members, which may or may not have a notch and/or an aperture.  FIG. 3A ,  FIG. 3B ,  FIG. 4A ,  FIG. 4B ,  FIG. 5A  and  FIG. 5B  are schematic views of various embodiments showing an elastic member coupled with a keycap. 
     Referring to  FIG. 1A , a top view of a keycap for a keyboard that is often used in the desktop computer or the portable computer is illustrated. As shown in  FIG. 1A , the reference number  10 A refers to the top surface of the keycap  10 , and the reference number  10 B refers to the inner surface of the keycap  10 . 
       FIG. 1B  is a schematic view of the inner surface  10 B of the keycap  10 , and shows that no cavity is formed in the inner surface  10 B of the keycap  10 . 
     Referring now to  FIG. 1C  to  FIG. 1F , the cavity of different shape is formed in the inner surface  10 B of the keycap  10  according to different embodiment, respectively. According to embodiments of the present invention, the cavity  101  located in the inner surface  10 B of the keycap  10  is designed for forming a gas channel between the keycap  10  and the elastic member  20  when the inner surface  10 B is coupled with the protrusion  20 A of the elastic member  20 . 
     For example, in one embodiment, the cavity  101  has a circular shape with at least two extended grooves  101 A (as shown in  FIG. 1C ). In another embodiment, the cavity  103  has a circular shape with extended grooves  103 A arranged in a radiant shape (as shown in  FIG. 1D ). In other embodiments, the cavity  105  has a rectangular shape (as shown in  FIG. 1E ), or the cavity  107  has a rectangular shape with at least two extended grooves  107 A (as shown in  FIG. 1F ). The width (or the diameter) of the cavities  101 ,  103 ,  105 ,  107  is preferably smaller than the diameter of the protrusion of the elastic member  20 . In the exemplary embodiment, the depths of the cavities  101 ,  103 ,  105 ,  107  and the extended grooves  101 A,  103 A,  107 A are about 0.1 to 0.2 millimeter, as shown in  FIG. 1C to 1F . It should be understood that the shape of the cavities or the number of the extended grooves are not limited to the embodiments described above. 
       FIG. 2A  to  FIG. 2C  shows the side views of an elastic member without any notch ( FIG. 2A ) and elastic members with notches and/or apertures ( FIGS. 2B and 2C ), respectively. As shown in  FIG. 2A , the elastic member  20  includes a protrusion  20 A disposed on an elastic body  20 B. The protrusion  20 A is arranged as a ring structure protruded from the elastic body  20 B, and no notch or aperture is formed in the protrusion  20 A. 
     Referring to  FIG. 2B , a top view of an elastic member with notches is shown. As shown in  FIG. 2B , the top end of the protrusion  20 A of the elastic member  20  has two notches  202 , which serves as a gas channel. Please note that the notch  202  may be disposed in any places of the top end of the protrusion  20 A to allow gas to flow through the notch  202  to/from the external environment. 
     Moreover, referring to  FIG. 2C , a top view of the elastic member with notches and apertures is illustrated. As shown in  FIG. 2C , the top end of the protrusion  20 A of the elastic member  20  has at least one notch  202 , and the sidewall of the protrusion  20 A of the elastic member  20  has at least one aperture  204 . As discussed above, the aperture  204  may also function as a gas channel so as to further facilitate the gas exhaust. 
     Referring to  FIG. 3A  to  FIG. 3B ,  FIG. 4A  to  FIG. 4B , and  FIG. 5A  to  FIG. 5B , three embodiments of the present invention are disclosed. In one embodiment, as shown in  FIG. 3A  and  FIG. 3B , the keycap  10  of  FIG. 1B  and the elastic member  20  of  FIG. 2B  are coupled. For example, when the inner surface  10 B of the keycap  10  is coupled with the protrusion  20 A of the elastic member  20 , with the design of the protrusion  20 A having notches  202  on its top end, a gas channel can be formed between the keycap  10  and the elastic member  20 . Then, referring to  FIG. 3B , when an external force is applied to the top surface  10 A of the keycap  10  to compress the elastic body  20 A, the gas within the elastic member  20  can be exhausted through the gas channel (i.e. the notch  202  located at the top end of the protrusion  20 A of the elastic member  20 ) to maintain a good typing “feel”. Furthermore, a second gas channel  203  is formed at an interface of the protrusion  20 A and the elastic body  20 B of the elastic member  20 , so that gas can flow from/to the elastic body  20 B through the protrusion  20 A. For example, a though hole  203  is formed in the interface of the protrusion  20 A and the elastic body  20 B, so that the spaces defined by the elastic body  20 B and the protrusion  20 A can be communicated. When an external force is applied to the key cap  10 , the elastic body  20 B is deformed, and the through hole  203  serving as the second gas channel allows the gas within the elastic body  20 B to flow to the space defined by the protrusion  20 A then exhausted through the notches  202 . 
     Referring now to  FIGS. 4A and 4B , in another embodiment, a keycap having an inner surface with a cavity and an elastic member without notches are disclosed. As shown in  FIG. 4A , a keycap  10  with a cavity shown in one of  FIGS. 1C ,  1 D, and  1 F is coupled with the top end of the protrusion  20 A of the elastic member  20 . Please note that in this embodiment, the keycap  10  of  FIG. 1C  is illustrated for description. As shown in  FIG. 4B , when the inner surface  10 A of the keycap  10  is coupled with the protrusion  20 A of the elastic member  20 , a gas channel can be formed between the keycap  10  and the elastic member  20  due to the cavity  101 . Therefore, when an external force is applied to the top surface  10 A of the keycap  10  to compress the elastic body  20 B, the gas within the elastic member  20  is exhausted through the gas channel. Similarly, a second gas channel  203  can be formed at the interface of the protrusion  20 A and the elastic body  20 B, so as to further facilitate the gas exhaust. 
     It is noted, in this embodiment, the inner diameter of the cavity  101 ,  103 ,  107  is preferably slightly smaller than the outer diameter of the protrusion  20 A of the elastic member  20 , so that when the protrusion  20 A of the elastic member  20  is coupled with the keycap  10 , the protrusion  20 A touches against the inner surface  10 B of the keycap  10  to form a gas channel. For example, since the outer diameter of the protrusion  20 A is slightly larger than the inner diameter of the cavity  101 ,  103 ,  107  of the keycap  10 , the top end of the protrusion  20 A does not directly touch against the surface defined within the cavity, in turn, does not block the path between the extended grooves  101 A,  103 A,  107 A to the cavity  101 ,  103 ,  107 . Furthermore, the outer diameter of the protrusion  20 A is preferably not larger enough to completely cover the cavity  101 ,  103 ,  105  with extended grooves  101 A,  103 A,  107 A. Therefore, when the protrusion  20 A is coupled with the keycap  10 , the cavity  101 ,  103 ,  107  with extended grooves  101 A,  103 A,  107 A can function as a gas channel for exhausting the gas from the elastic member  20 . Similarly, a second channel  203  can be formed at the interface of the protrusion  20 A and the elastic body  20 B as described. 
     In another embodiment, when the keycap  10  of  FIG. 1E  is implemented with the protrusion having no notch on its top end, such as the protrusion  20 A of  FIG. 2A , by manipulating the diameters of the protrusion and the cavity incorporation with the consideration of the difference in shape, such as circular and rectangular, a portion of the cavity not covered by the protrusion can function as a gas channel for exhausting the gas from the elastic member. 
       FIG. 5A  and  FIG. 5B  show a keycap  10  with an inner surface  10 B having a cavity and an elastic member  20  with a protrusion  20 A having a notch  202  at the top end of the protrusion  20 A according to another embodiment of the present invention. The inner surface  10 B of the keycap  10  has a cavity  101  with an extended groove (not shown), and the top end of the protrusion  20 A of the elastic member  20  has at least one notch  202 . As shown  FIG. 5B , the inner surface  10 B of the keycap  10  is coupled with the protrusion  20 A of the elastic member  20 , so that a first gas channel is formed between the protrusion  20 A and the keycap  10  as described above. Please note that the notch  202  at the top end of the protrusion  20 A may or may not be aligned with the extended groove of the inner surface  10 B of the keycap  10 . Thus, when an external force is applied to the top surface  10 A of the keycap  10  to compress the elastic body  20 B, the gas within the elastic member  20  may flow from the elastic body via the through hole  203  to the protrusion, and then be exhausted through the notch  202 , the extended groove  101 A,  103 A,  107 A, the cavity  101 ,  103 ,  105 ,  107  and/or the apertures  204  to effect the gas exhaust. In this embodiment, because the protrusion  20 A of  FIG. 2C  has apertures  204  in its sidewall, the keycap  10  coupled with the protrusion  20 A of  FIG. 2C  may or may not have a cavity, and a key switch with an exhaust structure (the apertures  204 ) still can be formed. Thus, when an external force is applied to the keycap  10  to compress the elastic member  20 , the gas within the elastic member  20  may be exhausted through the apertures  204  to maintain a good typing “feel”. 
     Although specific embodiments have been illustrated and described, it will be obvious to those skilled in the art that various modifications may be made without departing from what is intended to be limited solely by the appended claims.