Abstract:
A photoelectric switch, including: a base, an infrared tube, a keycap, a balance frame, a resetting mechanism, and a light-blocking member. The light-blocking member is configured to change the propagation direction of light emitted from the infrared tube to allow or block the light propagation in the infrared tube. The infrared tube is disposed on the base. The infrared tube includes a light-emitting end and a light-receiving end. The infrared tube, the balance frame, and the resetting mechanism are disposed beneath and covered by the keycap. In operation, upon being pressed by an external force, the balance frame leads the keycap to move downwards smoothly; the light-blocking member moves upwards or downwards along with the motion of the keycap and the balance frame or the resetting mechanism. The resetting mechanism is configured to reset the keycap or the balance frame.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of International Patent Application No. PCT/CN2015/091845 with an international filing date of Oct. 13, 2015, designating the United States, now pending, and further claims foreign priority benefits to Chinese Patent Application No. 201410536104.4 filed Oct. 13, 2014. The contents of all of the aforementioned applications, including any intervening amendments thereto, are incorporated herein by reference. Inquiries from the public to applicants or assignees concerning this document or the related applications should be directed to: Matthias Scholl P.C., Attn.: Dr. Matthias Scholl Esq., 245 First Street, 18th Floor, and Cambridge, Mass. 02142. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The invention relates to an ultrathin photoelectric switch. 
         [0004]    Description of the Related Art 
         [0005]    Typically, keyboard switches include a movable contact piece, a static contact piece, a keycap, and a button. The button often presents in the form of a guide pin, which has a relatively large thickness, leading to high material consumption. The button is disposed at the bottom center of the keycap. When the edge of the keycap is pressed, the button cannot move downward smoothly and steadily, so the contact and conduction between the movable contact piece and the static contact piece are unreliable. In addition, both the movable contact piece and the static contact piece are metals, which tend to be oxidized, causing bad contact. 
       SUMMARY OF THE INVENTION 
       [0006]    In view of the above-described problems, it is one objective of the invention to provide a photoelectric switch that is ultrathin, in which the contact and conduction between the movable contact piece and the static contact piece are stable and reliable. 
         [0007]    To achieve the above objective, in accordance with one embodiment of the invention, there is provided an ultrathin photoelectric switch capable of stable switching, comprising a base, an infrared tube, a keycap, a balance frame, a resetting mechanism, and a light-blocking member. The light-blocking member is configured to change a propagation direction of light emitted from the infrared tube to allow or block light propagation in the infrared tube. The infrared tube is disposed on the base. The infrared tube comprises a light-emitting end and a light-receiving end. The infrared tube, the balance frame, and the resetting mechanism are disposed beneath and covered by the keycap. In operation, upon being pressed by an external force, the balance frame leads the keycap to move downwards smoothly; the light-blocking member moves upwards or downwards along with the motion of the keycap and the balance frame or the resetting mechanism. The resetting mechanism is configured to reset the keycap or the balance frame. 
         [0008]    In a class of this embodiment, the base comprises a support body. The infrared tube and the support body are disposed on the base separately. On the base, an upper end of the support body is provided with a fulcrum slot. The balance frame comprises a first frame and a second frame. The first frame and the second frame are crisscrossed and articulated; a lower end of the first frame and a lower end of the second frame are respectively articulated with two ends of the base; an upper end of the first frame and an upper end of the second frame are respectively articulated with two ends of a bottom of the keycap; the resetting mechanism comprises an overturning member and a tension spring; one end of the overturning member butts against the fulcrum slot; the overturning member is capable of turning over relative to the support body; one end of the tension spring is connected to the other end of the overturning member, and the other end of the tension spring is connected to the upper end of the first frame. 
         [0009]    In a class of this embodiment, the light-blocking member is formed by extension of the overturning member and is integrated with the overturning member. 
         [0010]    In a class of this embodiment, the light-blocking member is a protrusion of the bottom of the keycap and is integrated with the keycap. 
         [0011]    In a class of this embodiment, the light-blocking member is a protrusion of the balance frame and is integrated with the balance frame. 
         [0012]    In a class of this embodiment, the infrared tube is a refractive infrared tube; the light-emitting end and the light-receiving end are encapsulated in a main body; and the light-blocking member is disposed above the main body and is capable of moving up and down. 
         [0013]    In a class of this embodiment, the infrared tube is a correlative infrared tube; the infrared tube comprises a light-emitting tube and light-receiving tube; the light-emitting end is disposed on the light-emitting tube, and the light-receiving end is disposed on the light-receiving tube; and the light-blocking member is disposed between the light-emitting tube and the light-receiving tube and is capable of moving up and down. 
         [0014]    Advantages of the ultrathin photoelectric switch according to embodiments of the invention are summarized as follows: 
         [0015]    The light-blocking member is used to change the propagation direction of the light and control the connection and disconnection of the infrared tube. Conventional methods that the movable contact piece is connected to the static contact piece are replaced, thus the bad contact caused by oxidization of the contact pieces is effectively avoided. The stability of the switching is improved, and the service life of the photoelectric switch is prolonged. The balance frame is used to equalize compression on the keycap. The light-blocking member is driven by the keycap, the balance frame, and the resetting mechanism, and the conventional guide pin which is thick is abandoned, thus the photoelectric switch is thin. In addition, no matter which place the finger of users presses on the keycap, the balance frame can equalize the compression on the keycap through linkage control, thus the motion of the light-blocking member is accurate and sensitive, so the photoelectric switch is easy to use. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The invention is described hereinbelow with reference to the accompanying drawings, in which: 
           [0017]      FIG. 1  is a schematic diagram of an ultrathin photoelectric switch in the off state in Example 1; 
           [0018]      FIG. 2  is a schematic diagram of an ultrathin photoelectric switch in the on state in Example 1; 
           [0019]      FIG. 3  is a schematic diagram of an ultrathin photoelectric switch in the off state in Example 2; 
           [0020]      FIG. 4  is a schematic diagram of an ultrathin photoelectric switch in the on state in Example 2; 
           [0021]      FIG. 5  is a schematic diagram of an ultrathin photoelectric switch in the off state in Example 3; 
           [0022]      FIG. 6  is a schematic diagram of an ultrathin photoelectric switch in the on state in Example 3; 
           [0023]      FIG. 7  is a schematic diagram of an ultrathin photoelectric switch in the off state in Example 4; 
           [0024]      FIG. 8  is a diagram illustrating a working principle of a light-blocking member in  FIG. 7 ; 
           [0025]      FIG. 9  is a schematic diagram of an ultrathin photoelectric switch in the on state in Example 4; 
           [0026]    FIG. 10  is a diagram illustrating a working principle of a light-blocking member in  FIG. 9 ; 
           [0027]      FIG. 11  is a schematic diagram of an ultrathin photoelectric switch in the off state in Example 5; 
           [0028]      FIG. 12  is a schematic diagram of an ultrathin photoelectric switch in the on state in Example 5; 
           [0029]      FIG. 13  is a schematic diagram of an ultrathin photoelectric switch in the off state in Example 6; and 
           [0030]      FIG. 14  is a schematic diagram of an ultrathin photoelectric switch in the on state in Example 6. 
       
    
    
       [0031]    In the drawings, the following reference numbers are used:  10 . Base;  20 . Infrared tube;  21 . Light-emitting end;  22 . Light-receiving end;  23 . Main body;  24 . Light-emitting tube;  25 . Light-receiving tube;  30 . Keycap;  40 . Balance frame;  41 . First frame;  42 . Second frame;  50 . Resetting mechanism;  51 . Overturning member;  52 . Tension spring;  60 . Light-blocking member;  70 . Support body; and  71 . Fulcrum slot. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0032]    For further illustrating the invention, experiments detailing an ultrathin photoelectric switch capable of stable switching are described below. It should be noted that the following examples are intended to describe and not to limit the invention. 
       EXAMPLE 1 
       [0033]    As shown in  FIGS. 1-2 , an ultrathin photoelectric switch capable of stable switching comprises a base  10 , an infrared tube  20 , a keycap  30 , a balance frame  40 , a resetting mechanism  50 , and a light-blocking member  60 . 
         [0034]    The base  10  comprises a support body  70 . The infrared tube  20  and the support body  70  are disposed on the base  10  separately. On the base, an upper end of the support body  70  is provided with a fulcrum slot  71 . 
         [0035]    The infrared tube  20  comprises a light-emitting end  21  and a light-receiving end  22 . In the example, the infrared tube  20  is a refractive infrared tube. The light-emitting end  21  and the light-receiving end  22  are encapsulated in a main body  23 . 
         [0036]    The balance frame  40  comprises a first frame  41  and a second frame  42 . The first frame  41  and the second frame  42  are crisscrossed and articulated. A lower end of the first frame  41  and a lower end of the second frame  42  are respectively articulated with two ends of the base  10 . An upper end of the first frame  41  and an upper end of the second frame  42  are respectively articulated with two ends of a bottom of the keycap  30 . The first frame  41  and the second frame  42  form an X-shaped structure. 
         [0037]    The resetting mechanism  50  is configured to reset the keycap  30  or the balance frame  40 . In the example, the resetting mechanism  50  operates to reset the balance frame  40 , so as to reset the keycap  30 . Specifically, in the example, the resetting mechanism  50  comprises an overturning member  51  and a tension spring  52 . One end of the overturning member  51  butts against the fulcrum slot  71 . The overturning member  51  is capable of turning over relative to the support body  70 . One end of the tension spring  52  is connected to the other end of the overturning member  51 , and the other end of the tension spring is connected to the upper end of the first frame  41 . 
         [0038]    The keycap  30  covers the infrared tube  20 . The balance frame  40  and the resetting mechanism  50  are disposed beneath the keycap  30 . The balance frame  40  is configured to equalize compression on the keycap  30 . The light-blocking member  60  is configured to change a propagation direction of light emitted from the infrared tube  20  and control the connection and disconnection of the infrared tube  20 . The keycap  30 , the balance frame  40 , or the resetting mechanism  50  drives the light-blocking member  60  to move up and down. In the example, the light-blocking member  60  is capable of moving up and down above the main body  23 , and the light-blocking member  60  is formed by extension of the overturning member  51  and is integrated with the overturning member  51 . 
         [0039]    In use, as shown in  FIG. 1 , the light-blocking member  60  is disposed above the infrared tube  20 . The infrared radiation emitted from the light-emitting end  21  is not received by the light-receiving end  22 , and the photoelectric switch is in the off state. As shown in  FIG. 2 , when the keycap  30  is pressed, the first frame  41  and the second frame  42  move downwards and overlap, meanwhile, the tension spring  52  is stretched, and the overturning member  51  is turned downwards, thus the light-blocking member  60  is turned downwards and is close to the infrared tube  20 . The infrared radiation emitted from the light-emitting end  21  is reflected by the light-blocking member  60  and radiates to the light-receiving end  22 . The light-receiving end  22  receives the infrared radiation, and the photoelectric switch is switched-on. When the keycap  30  is released, the tension spring  52  restores, and due to the restoration of the tension spring  52 , the first frame  41  and the second frame  42  moves upwards, meanwhile, the keycap  30  and the light-blocking member  60  are reset. The infrared radiation emitted from the light-emitting end  21  can no longer be received by the light-receiving end  22 , the photoelectric switch is in the off state once again. 
       EXAMPLE 2 
       [0040]    As shown in  FIGS. 3-4 , the example follows a basic structure in Example 1, except that in the example, the light-blocking member  60  is a protrusion of the bottom of the keycap  30  and is integrated with the keycap  30 . 
         [0041]    In use, as shown in  FIG. 3 , the light-blocking member  60  is disposed above the infrared tube  20 . The infrared radiation emitted from the light-emitting end  21  is not received by the light-receiving end  22 , and the photoelectric switch is in the off state. As shown in  FIG. 4 , when the keycap  30  is pressed, the first frame  41  and the second frame  42  move downwards and overlap, meanwhile, the tension spring  52  is stretched, and the overturning member  51  is turned downwards. The light-blocking member  60  also moves downwards with the keycap  30  and is close to infrared tube  20 . The infrared radiation emitted from the light-emitting end  21  is reflected by the light-blocking member  60  and radiates to the light-receiving end  22 . The light-receiving end  22  receives the infrared radiation, and the photoelectric switch is switched-on. When the keycap  30  is released, the tension spring  52  restores, and due to the restoration of the tension spring  52 , the first frame  41  and the second frame  42  moves upwards, meanwhile, the keycap  30  is reset, and the light-blocking member  60  are reset together with the keycap  30 . The infrared radiation emitted from the light-emitting end  21  can no longer be received by the light-receiving end  22 , the photoelectric switch is in the off state once again. 
       EXAMPLE 3 
       [0042]    As shown in  FIGS. 5-6 , the example follows a basic structure in Example 1, except that in the example, the light-blocking member  60  is a protrusion of the balance frame  40  and is integrated with the balance frame  40 . 
         [0043]    In use, as shown in  FIG. 5 , the light-blocking member  60  is disposed above the infrared tube  20 . The infrared radiation emitted from the light-emitting end  21  is not received by the light-receiving end  22 , the photoelectric switch is in the off state. As shown in  FIG. 6 , when the keycap  30  is pressed, the first frame  41  and the second frame  42  move downwards and overlap, meanwhile, the tension spring  52  is stretched, and the overturning member  51  is turned downwards. The light-blocking member  60  also moves downwards with the balance frame  40  and is close to infrared tube  20 . The infrared radiation emitted from the light-emitting end  21  is reflected by the light-blocking member  60  and radiates to the light-receiving end  22 . The light-receiving end  22  receives the infrared radiation, and the photoelectric switch is switched-on. When the keycap  30  is released, the tension spring  52  restores, and due to the restoration of the tension spring  52 , the first frame  41  and the second frame  42  moves upwards, meanwhile, the keycap  30  is reset, and the light-blocking member  60  are reset together with the balance frame  40 . The infrared radiation emitted from the light-emitting end  21  can no longer be received by the light-receiving end  22 , the photoelectric switch is in the off state once again. 
       EXAMPLE 4 
       [0044]    As shown in  FIGS. 7-10 , the example follows a basic structure in Example 1, except that the infrared tube  20  in the example is a correlative infrared tube, and comprises a light-emitting tube  24  and a light-receiving tube  25 . The light-emitting end  21  is disposed on the light-emitting tube  24 , and the light-receiving end  22  is disposed on the light-receiving tube  25 . The light-blocking member  60  is capable of moving up and down between the light-emitting tube  24  and the light-receiving tube  25 . 
         [0045]    In use, as shown in  FIG. 7-8 , the light-blocking member  60  is disposed between light-emitting tube  24  and the light-receiving tube  25 . The infrared radiation emitted from the light-emitting end  21  is blocked by the light-blocking member  60 , and is not received by the light-receiving end  22 , the photoelectric switch is in the off state. As shown in  FIG. 9-10 , when the keycap  30  is pressed, the first frame  41  and the second frame  42  move downwards and overlap, meanwhile, the tension spring  52  is stretched, and the overturning member  51  is turned downwards. The light-blocking member  60  is turned downwards by the overturning member  51 . The light-blocking member  60  no more blocks the infrared radiation, and the infrared radiation emitted from the light-emitting end  21  directly radiates to the light-receiving end  22 . The light-receiving end  22  receives the infrared radiation, and the photoelectric switch is switched-on. When the keycap  30  is released, the tension spring  52  restores, and due to the restoration of the tension spring  52 , the first frame  41  and the second frame  42  moves upwards, meanwhile, the keycap  30  is reset, and the light-blocking member  60  are reset together with the overturning member  51 . The light-blocking member  60  once again disposed between the light-emitting tube  24  and the light-receiving tube  25 . The infrared radiation emitted from the light-emitting end  21  can no longer be received by the light-receiving end  22 , the photoelectric switch is in the off state once again. 
       EXAMPLE 5 
       [0046]    As shown in  FIGS. 11-12 , the example follows a basic structure in Example 4, except that the light-blocking member  60  is a protrusion of the bottom of the keycap  30  and is integrated with the keycap  30 . 
         [0047]    In use, as shown in  FIG. 11 , the light-blocking member  60  is disposed between light-emitting tube  24  and the light-receiving tube  25 . The infrared radiation emitted from the light-emitting end  21  is not received by the light-receiving end  22 , and the photoelectric switch is in the off state. As shown in  FIG. 12 , when the keycap  30  is pressed, the first frame  41  and the second frame  42  move downwards and overlap, meanwhile, the tension spring  52  is stretched, and the overturning member  51  is turned downwards. The light-blocking member  60  moves downwards with the keycap  30 . The light-blocking member  60  no more blocks the infrared radiation, and the infrared radiation emitted from the light-emitting end  21  directly radiates to the light-receiving end  22 . The light-receiving end  22  receives the infrared radiation, and the photoelectric switch is switched-on. When the keycap  30  is released, the tension spring  52  restores, and due to the restoration of the tension spring  52 , the first frame  41  and the second frame  42  moves upwards, meanwhile, the keycap  30  is reset, and the light-blocking member  60  are reset together with the keycap  30 . The light-blocking member  60  once again disposed between the light-emitting tube  24  and the light-receiving tube  25 . The infrared radiation emitted from the light-emitting end  21  can no longer be received by the light-receiving end  22 , the photoelectric switch is in the off state once again. 
       EXAMPLE 6 
       [0048]    As shown in  FIGS. 13-14 , the example follows a basic structure in Example 4, except that the light-blocking member  60  is integrated with the balance frame  40 . 
         [0049]    In use, as shown in  FIG. 13 , the light-blocking member  60  is disposed between light-emitting tube  24  and the light-receiving tube  25 . The infrared radiation emitted from the light-emitting end  21  is not received by the light-receiving end  22 , the photoelectric switch is in the off state. As shown in  FIG. 14 , when the keycap  30  is pressed, the first frame  41  and the second frame  42  move downwards and overlap, meanwhile, the tension spring  52  is stretched, and the overturning member  51  is turned downwards. The light-blocking member  60  moves downwards with the balance frame  40 . The light-blocking member  60  no more blocks the infrared radiation, and the infrared radiation emitted from the light-emitting end  21  directly radiates to the light-receiving end  22 . The light-receiving end  22  receives the infrared radiation, and the photoelectric switch is switched-on. When the keycap  30  is released, the tension spring  52  restores, and due to the restoration of the tension spring  52 , the first frame  41  and the second frame  42  moves upwards, meanwhile, the keycap  30  is reset, and the light-blocking member  60  are reset together with the balance frame  40 . The light-blocking member  60  once again disposed between the light-emitting tube  24  and the light-receiving tube  25 . The infrared radiation emitted from the light-emitting end  21  can no longer be received by the light-receiving end  22 , the photoelectric switch is in the off state once again. 
         [0050]    The key point in the design of the invention is that: a light-blocking member is used to change the propagation direction of the light and control the connection and the disconnection of the infrared tube. The method that the movable contact piece is connected to static contact piece in the prior art is replaced, thus the bad contact caused by oxidization of the contact pieces is effectively avoided. The stability of the switching is improved, and the service life of the photoelectric switch is prolonged. The balance frame is used to equalize the compression on the keycap. The light-blocking member is driven by the keycap, the balance frame, and the resetting mechanism, and the conventional guide pin is abandoned, thus the photoelectric switch is thin. In addition, no matter which place the finger of users presses on the keycap, the balance frame can equalize the compression on the keycap through linkage control, thus the motion of the light-blocking member is accurate and sensitive, so the photoelectric switch is easy to use. 
         [0051]    While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.