Patent Publication Number: US-2022226519-A1

Title: Push button unit

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2021-004738 filed on Jan. 15, 2021. The entire disclosure of Japanese Patent Application No. 2021-004738 is hereby incorporated herein by reference. 
     BACKGROUND 
     Technical Field 
     The present invention relates to a push button unit comprising a push button, and more precisely relates to a push button unit having a function of disinfecting the operation surface of the push button. 
     Description of the Related Art 
     Some game machines installed in casinos, arcades, and other such game facilities are equipped with push buttons (for example, Patent Literature 1). Since these push buttons are operated by many different players, there is the risk that a virus that was clinging to the hand of a player who previously operated the push button will adhere to the operation surface of the push button. Therefore, in order for the next player to be able to play the game without worrying about any adhering virus, the employees of the game facility, etc., have to apply a disinfectant or the like to disinfect the operation surface frequently. In this specification, the word “disinfect” is used to mean “inactivate an adhering virus.” 
     The problem of viruses adhering to an operation surface is not limited to the push buttons of game machines, and the same applies to the push buttons provided to various other things such as elevators, vending machines, and ticket machines. 
     Also, push buttons have also been made of a material containing an antibacterial agent in the past (for example, Patent Literature 2). 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP-A 2016-214318 
         Patent Literature 2: JP-A H9-204560 
       
    
     SUMMARY 
     However, frequent disinfection work increases the burden on employees, and disinfection using a disinfectant also has a problem in that it accelerates the deterioration of the push button. On the other hand, a push button made of a material containing an antibacterial agent does not require disinfection work by employees, and therefore does not impose any more work on the facility operator, nor is the push button deteriorated by a disinfectant. However, this approach is not as appealing to users as disinfection work performed by an employee, and the user may become anxious about the instantaneous efficacy of inactivating an adhering virus, or the disinfecting effect of a material containing an antibacterial agent. 
     It is an object of one mode of the present invention to provide a push button unit with which any virus adhering to an operation surface is inactivated without relying on manual disinfection work, which allows users to operate the push button with more peace of mind. 
     The present invention employs the following configuration in order to solve the above problem. 
     Specifically, the push button unit according to one aspect of the present invention comprises a push button, a shutter that covers the push button in its closed state, a shutter mechanism that opens and closes the shutter, and a light irradiation unit having a light source that is disposed on the back surface of the shutter, is opposite the operation surface of the push button in the closed state of the shutter, and emits a light beam that inactivates a virus. 
     With the above configuration, the light irradiation unit is disposed on the back surface of the shutter, which is opened and closed by the shutter mechanism. The light irradiation unit comprises a light source that emits a light beam that inactivates a virus, and is provided so as to be opposite the operation surface of the push button when the shutter is closed. Consequently, the drive of the shutter mechanism and the light irradiation unit can be controlled so that any virus adhering to the operation surface will be inactivated (killed) by the light beam emitted from the light irradiation unit, without relying on manual disinfection work. Also, since the light beam is emitted while the push button is covered by the shutter, the light beam can be prevented from leaking to the outside. 
     In the push button unit according to the above-mentioned aspect, the configuration may further comprise a panel having an opening through which the push button comes out, and an elevating mechanism that raises and lowers the push button, wherein the push button comes out through the opening at the raised position, and the shutter is disposed on the back surface of the panel and blocks off the push button into a closed state, with the push button in its lowered position. 
     With the above configuration, the elevating mechanism raises and lowers the push button, and the push button comes out through an opening formed in the panel at the raised position. The shutter is disposed on the back surface of the panel, and the opening is blocked off in a state in which the push button is in its lowered position, resulting in a closed state. Consequently, the shutter can have a flat configuration that slides on the back surface of the panel, and the push button unit can be thinner than with a configuration having a three-dimensional shape that covers the push button. 
     In the push button unit according to the above-mentioned aspect, the configuration may be such that the elevating mechanism comprises a motor and a pantograph mechanism that moves a base on which the push button is mounted between a lowered position and a raised position by means of the drive force of the motor. With the above configuration, the pantograph mechanism can be used to increase the reduction ratio of the gear that transmits the drive force of the motor to the pantograph mechanism, so that even if a strong force is exerted on the push button that has come out through the opening, the push button can be held in its raised position. 
     The push button unit according to the above-mentioned aspect have a configuration comprising an instruction receiving unit that receives, at an arbitrary timing, an instruction to execute a disinfection operation that inactivates any virus adhering to the operation surface with the light beam. With the above configuration, providing the instruction receiving unit makes it possible to disinfect the operation surface of the push button whenever desired. 
     In the push button unit according to the above-mentioned aspect, the configuration may be such that the instruction receiving unit comprises a reflection sensor. With the above configuration, since a reflection sensor is used, a user can instruct the execution of the disinfection of the operation surface in a non-contact manner. 
     The present invention is also a control device for the push button unit according to the above-mentioned aspect, wherein, when an event occurs that triggers a disinfection operation that inactivates any virus adhering to the operation surface occurs with a light beam, said control device controls the drive of the shutter mechanism to put the shutter in its closed state, controls the drive of the light irradiation unit when the shutter is in its closed state to turn on the light source for a specific length of time, and after this lighting is completed, controls the drive of the shutter mechanism to put the shutter in its open state. 
     With the above configuration, when an event occurs that triggers a disinfection operation, the shutter enters its closed state, the light source is turned on for a specific length of time in that state, and once this lighting of the light source is finished, the shutter enters its open state and the push button comes out. Consequently, setting an event that will trigger the execution of a disinfection operation allows the disinfection operation to be executed at the set point in time. 
     In the control device for the push button unit according to the above-mentioned aspect, when an event occurs that triggers the execution of the disinfection operation for inactivating a virus adhering to the operation surface with the light beam, the drive of the elevating mechanism is controlled to move the push button to its lowered position, and when the push button moves to its lowered position, the drive of the shutter mechanism is controlled to put the shutter in its closed state, and when the shutter enters its closed state, the drive of the light irradiation unit is controlled to turn on the light source for a specific length of time, and once the lighting of the light source is completed, the drive of the shutter mechanism is controlled to put the shutter in its open state, and when the shutter enters its open state, the drive of the elevating mechanism is controlled to move the push button to its raised position. 
     With the above configuration, when an event occurs that triggers a disinfection operation, the push button is lowered, the shutter enters its closed state, the light source is turned on for a specific length of time in that state, and after the lighting of the light source is completed, the shutter enters its open state and the push button rises and comes out. Consequently, setting an event that will trigger the execution of a disinfection operation allows the disinfection operation to be executed at the set timing. 
     Effects 
     With one mode of the present invention, it is possible to realize a push button unit with which any virus adhering to the operation surface can be inactivated without relying on manual disinfection work, so the game can be enjoyed with more peace of mind. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an oblique view of a game machine in which a push button unit according to an embodiment is installed, showing a retracted state in which a push button has been retracted, and a normal state in which the push button has come out; 
         FIG. 2  is an oblique view of a push button unit installed in the game machine according to an embodiment, showing the normal state in which the push button has come out, and the retracted state in which the push button has been retracted; 
         FIG. 3  is an oblique view showing the inside of a front case in the push button unit installed in the game machine according to an embodiment, showing a state in which a shutter is open; 
         FIG. 4  is an oblique view showing the inside of the front case of the push button unit installed in the game machine according to an embodiment, showing a state in which the shutter is closed; 
         FIG. 5  is an oblique view showing the inside of the back case of the push button unit installed in the game machine according to an embodiment, showing a lowered state in which the push button is in its lowered position; 
         FIG. 6  is an oblique view showing the inside of the back case of the push button unit installed in the game machine according to an embodiment, showing a raised state in which the push button is in its raised position; 
         FIG. 7  is a detail view of the main components of the push button unit installed in the game machine according to an embodiment, at the portion where the left and right shutters abut against each other; 
         FIG. 8  is a schematic view showing the attachment of a timing belt and left and right sliders provided to a shutter mechanism in the push button unit installed in the game machine according to an embodiment; 
         FIG. 9  is an exploded oblique view of the push button in the push button unit installed in the game machine according to an embodiment; 
         FIG. 10  is a cross-sectional view of the main components, showing the lowered state and the raised state of a pantograph mechanism provided to an elevating mechanism in the push button unit installed in the game machine according to an embodiment; 
         FIG. 11  is an explanatory diagram showing the sensing of the position of the push button by third and fourth photosensors in the push button unit installed in the game machine according to an embodiment; 
         FIG. 12  is a block diagram showing a control system of the push button unit according to an embodiment; 
         FIG. 13  is a flowchart of the main sequence of the disinfection operation in the push button unit installed in the game machine according to an embodiment; 
         FIG. 14  is a flowchart showing the descent control sequence of the elevating mechanism in the push button unit installed in the game machine according to an embodiment; 
         FIG. 15  is a flowchart showing the control sequence of the shutter unit in the push button unit installed in the game machine according to an embodiment; 
         FIG. 16  is a diagram illustrating a push button unit according to a modification example, and is an oblique view showing a normal state in which the push button has come out, and a retracted state in which a push button has been retracted; and 
         FIG. 17  is a cross-sectional view of the main components of a push button unit comprising a plurality of push buttons according to a modification example, and shows a normal state in which the push buttons have come out and a retracted state in which the push buttons have been retracted. 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment relating to one aspect of the present disclosure (hereinafter, also referred to as “this embodiment”) will be described with reference to the drawings. In this embodiment, a configuration of a game machine such as a slot in which a push button unit is installed machine is given as an example of one mode of the push button unit disclosed herein. 
     (1) Application Example 
     First, an example of a situation in which a push button unit  10  is applied will be described with reference to  FIG. 1 .  FIG. 1  is an oblique view of the game machine  1  in which the push button unit  10  is installed in this embodiment, and shows a retracted state in which the push button  20  has been retracted, and a normal state in which the push button  20  has come out.  1001  in the drawing shows the retracted state, and  1002  shows the normal state. 
     As shown in  FIG. 1 , the game machine  1  is provided with a display monitor  2  at a position corresponding to the line of sight of the player at the upper part of the housing  4 , and an operation unit  3  is provided below the display monitor  2 . On the operation unit  3  are disposed an operation panel  5  constituted by an LCD and a touch panel, and a push button unit  10  comprising a push button  20 . Also, an insertion slot  6  for inserting tickets or banknotes and a payout slot  7  for paying out tickets are provided between the display monitor  2  and the operation unit  3 . Tickets and banknotes inserted into the slot  6  are sent to a ticket/banknote processing unit  8  (discussed below). Also, a ticket paid out from the ticket payout unit  9  is discharged from the payout slot  7 . 
     In the game machine  1 , the push button  20  is a button that is always operated in a game. For example, if the game executed by the game machine  1  is a slot machine game, the push button  20  is a spin button that begins the spin. Therefore, the push button  20  is touched much more frequently by the player than the operation panel  5 , and the operation surface  20   a  of the push button  20  is a place where viruses and the like are most likely to adhere. 
     The push button unit  10  disclosed herein has a function of disinfecting the operation surface  20   a  of the push button  20 . More specifically, as shown by  2002  in  FIG. 2 , the push button unit  10  comprising the push button  20  is designed such that the push button  20  retracts into a case  11 , and an opening  14  is closed off by a shutter  31 . As shown in  FIG. 4 , disinfecting LEDs  41  are disposed on the back surface of the shutter  31  and ultraviolet rays are emitted from the disinfecting LEDs  41  to inactivate any virus adhering to the operation surface  20   a  of the push button  20 . 
     This frees employees from having to perform frequent disinfection work, and reduces the burden on the employees. Also, since no disinfectant solution, the operation surface  20   a  is not deteriorated by a disinfectant solution, and the service life of the push button  20  can be extended. Also, if the player is made aware that the operation surface  20   a  is disinfected in its retracted state, the player can confirm that the push button  20  has been disinfected whenever the retracted state is seen. Consequently, the notion of the button having been disinfected is more appealing to the player than a push button made of a material containing an antibacterial agent, and the player can rest assured that any virus has been inactivated. 
     (2) Configuration Example 
     1. Overview of Push Button Unit  10   
       FIG. 2  is an oblique view of the push button unit  10  installed in the game machine  1  according to an embodiment, and shows a normal state in which the push button  20  has come out, and a retracted state in which the push button  20  has been retracted.  2001  in the drawing shows the normal state, and  2002  shows the retracted state. 
     As shown in  FIG. 2 , the push button unit  10  comprises a push button  20  and a case  11  for accommodating the push button  20 . The case  11  is in the form of a box that is thinner in the pressing direction of the push button  20 . The case  11  includes a front case  12  on which the operation surface of the push button  20  is located, and a back case  13  on which the push button  20  is installed. The push button unit  10  is installed in the operation unit  3  such that the upper surface of the front case  12  is flush with the a vanity panel surrounding the operation panel  5 , for example (see  FIG. 1 ). The upper surface of the front case  12  corresponds to a panel of the push button unit  10  in which is formed an opening  14  through which the push button  20  comes out. 
     In the case  11  is formed an opening  14  through which the push button  20  comes out. As shown by  2002  in the drawing, in the normal state the push button  20  has come out of the opening  14 , and its operation surface  20   a  sticks out from the opening  14 . On the other hand, as shown by  2002 , in the retracted state the push button  20  has gone inside the case  11 , and the opening  14  is closed off by the shutter  31 . 
       FIG. 3  is an oblique view showing the inside of the front case  12  of the push button unit  10  according to an embodiment, and shows a state in which the shutter  31  is open.  FIG. 4  is an oblique view showing the inside of the front case  12  of the push button unit  10  according to an embodiment, and shows a state in which the shutter  31  is closed. 
     As shown in  FIGS. 3 and 4 , a shutter unit  30  and a sensor unit  80  are installed on the inside (back side) of the front case  12 . The shutter unit  30  comprises a shutter  31  that closes off the opening  14 , a shutter mechanism  32  that opens and closes the shutter  31 , and an ultraviolet irradiation unit (light beam irradiation unit)  40  that is installed on the back surface of the shutter  31 . As will be described in detail below, the ultraviolet irradiation unit  40  emits ultraviolet rays as a light beam for inactivating (killing) any virus adhering to the operation surface  20   a  of the push button  20 . The sensor unit  80  receives an instruction from the outside to execute disinfection of the operation surface  20   a  with the ultraviolet irradiation unit  40 . 
       FIG. 5  is an oblique view showing the inside of the back case  13  of the push button unit  10  according to an embodiment, and shows a lowered state in which the push button  20  is in its lowered position.  FIG. 6  is an oblique view showing the inside of the back case  13  of the push button unit  10  according to an embodiment, and shows a raised state in which the push button  20  is in its raised position. 
     As shown in  FIGS. 5 and 6 , an elevating unit  50  is installed on the inside (back side) of the back case  13 . The elevating unit  50  is provided with the push button  20  and an elevating mechanism  51  for raising and lowering the push button  20 . 
     2. Configuration of Shutter Unit  30   
     First, the configuration of the shutter unit  30  will be described. As mentioned above, the shutter unit  30  comprises the shutter  31 , the shutter mechanism  32 , and the ultraviolet irradiation unit  40 . These members constituting the shutter mechanism  32  are unitized. 
     2-1. Shutter  31  and Shutter Mechanism  32   
     As shown in  FIGS. 3 and 4 , the shutter  31  is provided slidably on the back surface of the front case  12 . In this embodiment, the shutter  31  consists of two shutters that move in opposite directions at the same time. For convenience of convenience in the following description, the push button unit  10  shall be assumed to be installed in the operation unit  3  such that the two-piece shutter  31  opens in the left-right direction and the sensor unit  80  is located to the rear. The shutter located on the left side when installed in the game machine  1  is referred to as the left shutter  31 L, and the shutter located on the right side is referred to as the right shutter  31 R. However, when it is not necessary to discuss the left and right shutters  31 L and  31 R separately, they shall be referred to simply as the shutter  31 . 
     The left and right shutters  31 L and  31 R are opened and closed by the shutter mechanism  32 , moving closer together during the transition from the open state to the closed state, and moving away from each other during the transition from the closed state to the open state.  FIG. 7  is a detail view of the main components of the push button unit  10  according to an embodiment, at the portion where the left and right shutters  31 L and  31 R abut against each other. As shown in  FIG. 7 , the ends of the left and right shutters  31 L and  31 R that abut each other form a lap joint so as to overlap each other in plan view. This reliably prevents ultraviolet rays from the ultraviolet irradiation unit  40  (discussed below) from leaking out through the gap between the left and right shutters  31 L and  31 R in the closed state. 
     As shown in  FIGS. 3 and 4 , the shutter mechanism  32  comprises an opening and closing motor  33 , a reduction gear  34 , a pair of pulleys  35   a  and  35   b , a timing belt  36 , left and right sliders  37 L and  37 R, left and right rails  38 L and  38 R, a shutter rail  39 , and first and second photosensors PS 1  and PS 2 . 
     The opening and closing motor  33  is the drive source for opening and closing the shutter  31 . The reduction gear  34  is a component that transmits the drive force of the opening and closing motor  33  to the timing belt  36 . The drive shaft  33   a  of the opening and closing motor  33  engages with the reduction gear  34 , and the reduction gear  34  is rotated by the drive force of the opening and closing motor  33 . The pulleys  35   a  and  35   b  are members that rotate the timing belt  36 , and the pulley  35   a  is fixed to the reduction gear  34 . The timing belt  36  is wound around the pulleys  35   a  and  35   b , and teeth formed on the pulley  35   a  on the drive side mesh with teeth formed on the inside of the timing belt  36 . 
     The left and right sliders  37 L and  37 R and the left and right rails  38 L and  38 R are provided corresponding to the left and right shutters  31 L and  31 R. The left slider  37 L is connected to the left shutter  31 L and the timing belt  36 . When the timing belt  36  rotates, the left slider  37 L moves on the left rail  38 L, causing the connected left shutter  31 L to move. Similarly, the right slider  37 R is connected to the right shutter  31 R and the timing belt  36 . When the timing belt  36  rotates, the right slider  37 R moves on the right rail  38 R, causing the connected right shutter  31 R to move. 
     The ends of the left and right shutters  31 L and  31 R that are not connected to the left and right sliders  37 L and  37 R are supported slidably on the shutter rail  39 . 
       FIG. 8  is a schematic view showing the attachment of the timing belt  36  and the left and right sliders  37 L and  37 R included in the shutter mechanism  32  of the push button unit  10  according to an embodiment. As shown in  FIG. 8 , the left and right sliders  37 L and  37 R are attached in vertical symmetry at positions of half the circumference of the timing belt  36 . Consequently, when the timing belt  36  rotates in the direction indicated by the arrows, the left and right sliders  37 L and  37 R move closer together, and the left and right shutters  31 L and  31 R move in the closing direction. Conversely, when the timing belt  36  rotates in the opposite direction from that indicated by the arrows, the left and right sliders  37 L and  37 R move away from each other, and the left and right shutters  31 L and  31 R move in the opening direction. 
     Returning to  FIGS. 3 and 4 , the first and second photosensors PS 1  and PS 2  detect whether the shutter  31  is open or closed. The first photosensor PS 1  detects an open state (fully open state) in which the shutter  31  is open, and the second photosensor PS 2  detects a closed state (fully closed) in which the shutter  31  is closed. 
     More specifically, the first photosensor PS 1  is disposed at a position where light is not blocked until the left shutter  31 L is fully opened (see  FIG. 4 ), and where light is blocked by the left slider  37 L when the left shutter  31 L is fully opened (see  FIG. 3 ). This allows the first photosensor PS 1  to detect that the shutter  31  is in its open state when the light is being blocked. 
     On the other hand, the second photosensor PS 2  is disposed at a position where light is not blocked until the right shutter  31 R is completely closed (see  FIG. 3 ), and where light is blocked by the right slider  37 R when the right shutter  31 R is fully closed (see  FIG. 4 ). This allows the second photosensor PS 2  to detect that the shutter  31  is in its closed state when the light is being blocked. 
     As described above, the left and right shutters  31 L and  31 R move symmetrically as the timing belt  36  rotates, so if the position of either of the left and right shutters  31 L and  31 R is detected, there is no need to detect the position of the other. 
     2-2. Ultraviolet Irradiation Unit  40   
     As shown in  FIGS. 3 and 4 , the ultraviolet irradiation unit  40  is installed on the back surface of the shutter  31  and emits ultraviolet rays as a light beam that inactivates any virus adhering to the operation surface  20   a  of the push button  20 . The ultraviolet irradiation unit  40  comprises disinfecting LEDs (light sources)  41  that emit ultraviolet rays, and an LED drive circuit  42  that drives the disinfecting LED  41 . The disinfecting LEDs  41  are disposed so that ultraviolet rays cover the entire operation surface  20   a . The disinfecting LEDs  41  and the LED drive circuit  42  are installed on the substrate  43 . 
     In this embodiment, the ultraviolet irradiation unit  40  is divided into two parts that are installed corresponding to the left and right shutters  31 L and  31 R. When the left and right shutters  31 L and  31 R are in their closed state, the disinfecting LEDs  41  face the operation surface  20   a , and the ultraviolet rays emitted from the disinfecting LEDs  41  irradiate the operation surface  20   a.    
     3. Configuration of Elevating Unit  50   
     Next, the configuration of the elevating unit  50  will be described. As discussed above, the elevating unit  50  comprises the push button  20  and the elevating mechanism  51  for raising and lowering the push button  20 . 
     3-1. Push Button  20   
       FIG. 9  is an exploded oblique view of the push button  20  in the push button unit  10  according to an embodiment. As shown in  FIG. 9 , the push button  20  comprises a bezel  21 , a base  22 , a button body  23 , a pressure-sensitive sensor substrate  27 , an LED substrate  28 , mechanical parts, and so forth. The bezel  21  is a cover member for covering (protecting) the outer peripheral part of the push button  20 . The button body  23  is the portion that is pressed, and is supported between the bezel  21  and the base  22  so that the pressing operation can be performed. The upper surface of the button body  23  and the upper surface of the bezel  21  correspond to the operation surface  20   a . The button body  23  is made of a transparent material, and an annular rubber portion  24  is fitted to the outer peripheral part thereof. The rubber portion  24  on the outer peripheral part is sandwiched between the bezel  21  and the base  22  so that liquid will not find its way inside the push button  20 . 
     The mechanical parts include a plurality of rubber clickers  25  and a plurality of springs  26 . The rubber clickers  25  give a tactile click when the button body  23  is pressed, and the spring  26  returns the pressed button body  23 . The pressure-sensitive sensor substrate  27  comprises a pressure-sensitive sensor  29  (see  FIG. 12 ) that detects the pressing of the button body  23 , and therefore detects when the button body  23  is pressed. The LED substrate  28  comprises a plurality of LEDs (not shown) and illuminates the outer peripheral portion of the button body  23 . 
     3-2. Elevating Mechanism  51   
     As shown in  FIGS. 5 and 6 , the push button  20  is installed on a base  52 , and is raised and lowered along with the base  52  by the elevating mechanism  51 . The elevating mechanism  51  comprises an elevating motor  53 , two reduction gears  54 , a ball screw  55 , a pantograph mechanism  60 , and third and fourth photosensors PS 3  and PS 4 . The push button  20  and these members constituting the elevating mechanism  51  are assembled on the base plate to form a unit. 
     The elevating motor  53  is the drive source that raises and lowers the push button  20 . The two reduction gears  54  are components that transmit the drive force of the elevating motor  53  to the ball screw  55 . The two reduction gears  54  are rotated by the driving force of the elevating motor  53 . One of the reduction gears  54  meshes with the drive shaft (not shown) of the elevating motor  53 , and the ball screw  55  is fixed to the shaft of the other reduction gear. The reduction gears  54  are rotated by the drive force of the elevating motor  53 . The ball screw  55  is a member that raises and lowers the pantograph mechanism  60 . 
     The pantograph mechanism  60  has a plurality of frame pieces  62  arranged so as to intersect each other, and comprises a frame portion  61  on which an intersection point  62   a  is axially supported. In this embodiment, the frame portion  61  has two frame pieces  62 , and also has a front frame portion  61 F and a back frame portion  61 B in the front-back direction intersecting the left-right direction, which is the opening and closing direction of the shutter  31 . 
     The upper ends of each of the two frame pieces  62  in the front and back frame portions  61 F and  61 B are attached to the base  52 , and the base  52  is supported by the four frame pieces  62 . The lower ends of the two frame pieces  62  in the front and back frame portions  61 F and  61 B are attached to the shafts of round support columns  63 R and  63 L disposed on the left and right. More specifically, the lower ends of the two frame pieces  62  of the front frame portion  61 F are attached to the front shafts of the left and right round support columns  63 L and  63 R, and the lower ends of the two frame pieces  62  of the back frame portion  61 B are attached to the rear shafts of the left and right round support columns  63 L and  63 R. 
     The shafts at both ends of the left and right round support columns  63 L and  63 R are supported by a front support plate  64 F and a back support plate  64 B installed in the front-back direction. Of these, the shaft of the right round support column  63 R is received at a fixed position by the front and back support plates  64 F and  64 B. The shaft of the left round support column  63 L is slidably received by slots  64   a  that are formed in the front and back support plates  64 F and  64 B and are longer in the left-right direction. The ball screw  55  is disposed so as to pass through the center of the left and right round support columns  63 R and  63 L in the lengthwise direction (front-back direction). 
       FIG. 10  is a cross-sectional view of the main components, showing the lowered state and the raised state of the pantograph mechanism  60  provided to the elevating mechanism  51  in the push button unit according to an embodiment.  10001  in the drawing shows the lowered state, and  10002  shows the raised state. As shown by  10001 , in the lowered state the left round support column  63 L is located at the left end, and the two frame pieces  62  of the front and back frame portions  61 F and  61 B extend along the ball screw  55 . When the ball screw  55  rotates in a specific direction from this state, the left round support column  63 L moves horizontally to the right and approaches the right round support column  63 R as shown by  10002 . When the left round support column  63 L approaches the right round support column  63 R, the two frame pieces  62  in the front and back frame portions  61 F and  61 B rise up in the direction away from the ball screw, and the base  52  is pushed up, resulting in the raised state. 
     When the ball screw  55  rotates from the raised state in the opposite direction from that when the ball screw  55  is raised, the left round support column  63 L moves horizontally to the left and away from the right round support column  63 R. When the left round support column  63 L moves away from the right round support column  63 R, the two frame pieces  62  in the front and back frame portions  61 F and  61 B fold toward the ball screw  55 , and the base  52  is lowered, resulting in the lowered state. 
     In this embodiment, the amount by which the push button  20  is raised by the pantograph mechanism  60  is about 20 mm, and the reduction ratio of the reduction gears  54  is 0.1389. In this case, the elevating motor  53  has to rotate about 15 times to raise the push button  20  by 20 mm. Thus increasing the reduction ratio makes the push button  20  more resistant to sinking even if hit forcefully. 
     Returning to  FIGS. 5 and 6 , the third and fourth photosensors PS 3  and PS 4  sense the position of the push button  20 . In this embodiment, the third and fourth photosensors PS 3  and PS 4  are installed on the left side, which is the opposite side from the elevating motor  53 . A detection piece  56  that blocks light from reaching the third and fourth photosensors PS 3  and PS 4  is attached to the base  52 . 
       FIG. 11  is an explanatory diagram showing the sensing of the position of the push button  20  by the third and fourth photosensors PS 3  and PS 4  in the push button unit according to an embodiment.  11001  in the drawing shows the lowered state (in the lowered position), and  11002  shows the raised state (in the raised position). As shown in  FIG. 11 , the third and fourth photosensors PS 3  and PS 4  are installed at the same height, and the detection piece  56  has light blocking walls  56   a  and  56   b  that are offset in the up and down direction (height direction). 
     As by  11001  in the drawing, in the lowered state of the push button  20 , the fourth photosensor PS 4  is shielded from light by the light blocking wall  56   b , and the third photosensor PS 3  is not shielded from light by the light blocking wall  56   a . When the push button  20  starts to rise, the third photosensor PS 3  is also shielded from light by the light blocking wall  56   a , and the third and fourth photosensors PS 3  and PS 4  are both in a light-shielded state. 
     Then, when the push button  20  reaches its raised position, as shown by  11002 , the third photosensor PS 3  remains shielded from light by the light blocking wall  56   a , but the fourth photosensor PS 4  is not shielded from light by the light blocking wall  56   b . In this way, the position of the push button  20  (lowered position, raised position, or intermediate position) can be sensed from the combination in which the third and fourth photosensors PS 3  and PS 4  are or are not shielded from light. 
     3-3. Sensor Unit  80   
     The sensor unit (instruction receiving unit)  80  receives, from the outside of the push button unit  10 , an instruction to execute the disinfection of the operation surface  20   a  with the ultraviolet irradiation unit  40 . As shown in  FIGS. 3 and 4 , the sensor unit  80  comprises a photosensor  81  that is a reflection sensor, and is attached to the back side of the front case  12 . As shown in  FIG. 2 , a window portion  12   a  through which the light of the photosensor  81  of the sensor unit  80  passes is provided at the site in the front case  12  where the sensor unit  80  is installed. The player can instruct the execution of the disinfection of the operation surface  20   a  in a non-contact manner by holding his or her hand over the window portion  12   a.    
     4. Control Device  70   
       FIG. 12  is a block diagram showing a control system of the push button unit  10  according to an embodiment. The control device  70  is composed of, for example, a computer device made up of a CPU (central processing unit), an arithmetic processing unit such as a dedicated processor, and the like, and controls the operation of the various components of the push button unit  10 . The control device  70  is connected to the opening and closing motor  33 , the LED drive circuit  42 , and the elevating motor  53  of the push button unit  10 . Also, detection signals are inputted to the control device  70  from the pressure-sensitive sensor  29 , the first to fourth photosensors PS 1  to S 4 , and the sensor unit  80 . 
     The control device  70  comprises a pressing detection unit  74 , a shutter control unit  71 , an irradiation control unit  72 , and an elevating control unit  73 . The pressing detection unit  74  determines that the push button  20  has been pressed when a detection signal is inputted from the pressure-sensitive sensor  29 . When a detection signal is inputted from the sensor unit  80  (when an instruction to execute disinfection work is received), the shutter control unit  71 , the irradiation control unit  72 , and the elevating control unit  73  control the drive of the opening and closing motor  33 , the LED drive circuit  42 , and the motor  53  to execute the disinfection work. 
     More precisely, the shutter control unit  71  uses the detection signals of the first and second photosensors PS 1  and PS 2  to control the drive of the opening and closing motor  33  and to open and close the shutter  31 . The irradiation control unit  72  controls the drive of the LED drive circuit  42  to turn on the disinfecting LEDs  41 . The elevating control unit  73  uses the detection signals of the third and fourth photosensors PS 3  and PS 4  to control the drive of the elevating motor  53  and to raise and lower the push button  20 . 
     The control device  70  may be provided with the push button unit  10 , or may be provided as a part of the control device of the game machine  1  (see  FIG. 1 ) on which the push button unit  10  is mounted. 
     5. Disinfection Operation of Push Button Unit  10   
     5-1. Main Sequence of Disinfection Operation 
       FIG. 13  is a flowchart of the main sequence of the disinfection operation in the push button unit  10  according to an embodiment. As shown in  FIG. 13 , the control device  70  constantly determines whether or not a detection signal has been inputted from the sensor unit  80  (S 1 ). If it is determined in S 1  that a detection signal has been inputted, the elevating control unit  73  drives the elevating motor  53  to move the push button  20  to its lowered position (S 2 ). When the push button  20  moves to its lowered position, the shutter control unit  71  drives the opening and closing motor  33  to close the shutter  31  (S 3 ). 
     When the shutter  31  closes, the irradiation control unit  72  drives the LED drive circuit  42  to turn on the disinfecting LEDs for a specific length of time (S 4 ). This length of time is long enough for any virus adhering to the operation surface  20   a  to be inactivated by the ultraviolet rays from the disinfecting LEDs  41 , and is set to about 10 seconds, for example. In S 4 , once the LEDs have been on for the specific length of time, the shutter control unit  71  drives the opening and closing motor  33  to open up the shutter  31  (S 5 ). When the shutter  31  is opened in S 5 , the elevating control unit  73  drives the elevating motor  53  to move the push button  20  to its raised position (S 6 ). After this, the control device  70  returns to the processing of S 1 . 
     The processing of S 5  and S 6  for opening the shutter  31  and making the push button  20  come out does not have to be performed immediately after the lighting of the disinfecting LEDs  41  for a specific length of time is completed, as long as it is after the completion of this lighting. For example, the processing of S 5  and S 6  may be executed at the point when it is detected that there is a situation (event) in which the push button  20  needs to be operated, such as the start of a game on the game machine or the like in which the push button unit  10  is installed. 
     5-2. Elevating Mechanism Control Sequence 
       FIG. 14  is a flowchart showing the descent control sequence of the elevating mechanism  51  in the push button unit  10  according to an embodiment. The descent control sequence of  FIG. 14  is executed in S 2  of  FIG. 13 . 
     As shown by  11002  in  FIG. 11 , in the raised state in which the push button  20  is in its raised position, the third photosensor PS 3  is in a light-shielded state and the fourth photosensor PS 4  is in a non-light-shielded state. When the elevating control unit  73  starts driving the elevating motor  53  (S 11 ) in order to lower the push button  20  from its raised position, both the third and fourth photosensors PS 3  and PS 4  are in a light-shielded state. 
     The elevating control unit  73  drives the elevating motor  53  until the third photosensor PS 3  is in a non-light-shielded state. As shown by  11001  in  FIG. 11 , when the push button  20  reaches its lowered position, the third photosensor PS 3  is in a non-light-shielded state and the fourth photosensor PS 4  is in a light-shielded state. When the third photosensor PS 3  is in a non-light-shielded state (Yes in S 12 ), the elevating control unit  73  stops driving the elevating motor  53  (S 13 ). After this, the control device  70  proceeds to the control sequence of the shutter unit  30  shown in  FIG. 15 . 
     Although not shown, the ascending control sequence for moving the push button  20  to its raised position, which is executed in S 6  of  FIG. 13 , is the reverse of  FIG. 14 . That is, the elevating control unit  73  drives the elevating motor  53  to raise the push button  20  until the fourth photosensor PS 4  is in a non-light-shielded state, and when the fourth photosensor PS 4  is in a non-light-shielded state, the drive of the elevating motor  53  is stopped. 
     5-3. Control Sequence of Shutter Unit  30   
       FIG. 15  is a flowchart showing the control sequence of the shutter unit  30  in the push button unit  10  installed in the game machine  1  according to an embodiment. The control sequence in  FIG. 15  is executed in S 3  to S 5  of  FIG. 13 . 
     As shown in  FIG. 3 , when the shutter  31  is in its open state (fully open), the first photosensor PS 1  is in a light-shielded state and detects this fully open state. The second photosensor PS 2  that detects a closed state is in a non-light-shielded state. In order to close the shutter  31 , the shutter control unit  71  starts driving the opening and closing motor  33  (S 21 ). When the shutter  31  starts to close, the first and second photosensors PS 1  and PS 2  are both in a non-light-shielded state. The shutter control unit  71  drives the opening and closing motor  33  until the second photosensor PS 2  that detects a closed state is in a light-shielded state. As shown in  FIG. 4 , when the shutter  31  is closed, the second photosensor PS 2  is in a light-shielded state. When the second photosensor is in a light-shielded state (Yes in S 22 ), the shutter control unit  71  drives the opening and closing motor  33  by a specific number of pulses, confirms the drive for this specific number of pulses, and then stops (S 23 ). 
     This processing of S 23  is executed in order to prevent the shutter  31  from not completely closing, which would result in a tiny gap. That is, in the control to stop the opening and closing motor  33  immediately after the second photosensor PS 2  is shielded from light by the right slider  37 R (Yes in S 22 ), variance in the assembly position of the second photosensor PS 2  may produce a tiny gap in the closed state of the shutter  31 . If S 23  is executed, any variance in the assembly position of the second photosensor PS 2  can be absorbed and the shutter  31  can be closed without leaving a tiny gap. 
     The fact that the shutter  31  is not completely closed can be detected in the following two ways. One is when the second photosensor PS 2  is not shielded from light even after a specific period of time has elapsed since the opening and closing motor  33  started to be driven. The other is when it is detected that the opening and closing motor  33  has not rotated by a specific angle even after a specific period of time has elapsed even though the specified number of pulses was sent to the opening and closing motor  33  after the second photosensor PS 2  is in a light-shielded state. A Hall element is provided to the motors constituting the opening and closing motor  33  and the like, and this allows the motor to confirm its own rotational position. 
     When the shutter  31  is completely closed by the processing of S 23 , the irradiation control unit  72  turns on the disinfecting LEDs  41  for a predetermined length of time and then turns them off (S 24 ). Consequently, the operation surface  20   a  of the push button  20  is irradiated with ultraviolet rays, and any adhering virus is inactivated. 
     After confirming that the disinfecting LEDs  41  have been turned off, the shutter control unit  71  starts driving the opening and closing motor  33  in order to open the shutter  31  (S 26 ). When the shutter  31  starts opening, the first and second photosensors PS 1  and PS 2  both go back into its non-light-shielded state. The shutter control unit  71  drives the opening and closing motor  33  until the first photosensor PS 1  that detects an open state is back in its light-shielded state. When the first photosensor PS 1  is in its light-shielded state (Yes in S 26 ), the shutter control unit  71  stops driving the opening and closing motor  33  (S 27 ). 
     6. Effect 
     With the above configuration, the push button unit  10  comprises the ultraviolet irradiation unit  40 , and in a state in which the push button  20  has been retracted, the operation surface  20   a  is irradiated with ultraviolet rays to inactivate any virus adhering to the operation surface  20   a . This makes it possible to disinfect the operation surface  20   a  without relying on disinfection work in which a worker applies a disinfectant solution, freeing the worker from frequent disinfection work and reducing the burden on the worker. Also, since no disinfectant solution is used, the operation surface  20   a  will not be deteriorated by disinfectant solution, and the service life of the push button  20  can be extended. 
     Also, because a player can recognize that the operation surface  20   a  has been disinfected in its retracted state, the player can confirm that the push button  20  has been disinfected just by seeing the retracted state. Consequently, the notion of the button having been disinfected is more appealing to the player than a push button made of a material containing an antibacterial agent, and the player can rest assured that any virus has been inactivated. 
     Also, with the above configuration, the ultraviolet irradiation by the ultraviolet irradiation unit  40  is performed in a state in which the shutter  31  has been completely closed. This reliably prevents the player from looking at the emitted ultraviolet rays. 
     Also, with the above configuration, the elevating mechanism  51  for raising and lowering the push button  20  is provided, and the shutter  31  closes off the opening  14  in a state in which the push button  20  is lowered. With this configuration, the shutter  31  can have a flat configuration, and the push button unit  10  can be thinner. This allows for installation in a limited space such as the operation unit  3  of the game machine  1  (see  FIG. 1 ). 
     Also, with the above configuration, the elevating mechanism  51  comprises a pantograph mechanism that raises and lowers the base  52  using the drive force of the elevating motor  53 . Using the pantograph mechanism increases the reduction ratio of the reduction gear  54  that transmits the drive force of the elevating motor  53  to the pantograph mechanism, so the push button  20  can be held in its raised position even if a large force is applied to the push button  20 . 
     Also, with the above configuration, since the sensor unit  80  is designed to receive an instruction to execute the disinfection operation at any point in time, the player can disinfect the push button whenever desired. In particular, with the above configuration, since the sensor unit  80  comprises a reflection sensor, a player can issue a command to execute a disinfection operation on the push button in a non-contact manner. 
     (3) Modification Examples 
     An embodiment of the present invention was described in detail above, but the above description is merely an example of the present invention in all respects. It should go without saying that various improvements and modifications are possible without departing from the scope of the present invention. For instance, the following modifications can be made. In the following, Constituent elements that are the same as in the above embodiment will be numbered the same, and points that are the same as in the above embodiment may be omitted as appropriate. The following modification examples can be combined as appropriate. 
     3.1 
     In the main sequence of the disinfection operation shown in  FIG. 13 , the control device  70  constantly determines whether or not a detection signal has been inputted from the sensor unit  80  in S 1 , and if it is determined that a detection signal has been inputted, S 2  is executed to start the disinfection operation. That is, with the configuration of the embodiment described above, the instruction inputted by the player to the sensor unit  80  was an event that triggered the execution of a predetermined disinfection operation. 
     However, the instruction to execute the disinfection operation by the sensor unit  80  is only an example of the above-mentioned trigger. For instance, the completion of the operation on the push button  20  may be detected by some method, and this may serve as a trigger. For example, in the case of installation in the game machine  1 , the end of a game on this game machine can be an event that triggers the execution of the disinfection operation. However, if the push button unit  10  is installed in the game machine  1 , the event that triggers the execution of the disinfection operation is preferably a player change. 
     3.2 
     When the push button unit  10  is installed in the game machine  1  (see  FIG. 1 ), the installation space is limited, so the push button unit  10  needs to have a thin configuration. Therefore, the elevating mechanism  51  is provided to lower the push button  20 , and the push button  20  is covered by the shutter  31  in its lowered state. With this configuration, the shutter can be configured in a flat shape such as that of the shutter  31 , and the thickness of the push button unit  10  can be reduced. On the other hand, if there is plenty of installation space, the elevating mechanism  51  need not be provided, and the shutter may be three-dimensionally configured to cover the push button  20 . 
       FIG. 16  is a diagram illustrating the push button unit  100  according to a modification example, and shows the normal state in which the push button  20  has come out, and the retracted state in which the push button  20  has been retracted.  16001  and  16003  show the normal state in the drawing, and  16002  shows the retracted state. 
     As shown in  FIG. 16 , the push button unit  100  comprises a dome-shaped three-dimensional shutter  101  instead of the flat shutter  31  used in the push button unit  10 . The shutter  101  is made up of left and right shutters  101 L and  101 R. An ultraviolet irradiation unit (light irradiation unit)  40  is installed on the back surface of the shutter  101 . Using the three-dimensional shutter  101  eliminates the need to raise and lower the push button  20 , so there is no need to provide the elevating mechanism  51 . 
     3.3 
     A configuration comprising one push button  20  was given above as an example of the push button unit  10 , but the configuration may also comprise a plurality of push buttons  20 . The push button unit  10  comprising a plurality of push buttons  20  is installed in an elevator or a ticket vending machine, for example. 
       FIG. 17  is a cross-sectional view of the main components of a push button unit  200  comprising a plurality of push buttons  20  according to a modification example, and shows the normal state in which the push buttons have come out and the retracted state in which the push buttons have been retracted.  17001  shows the normal state, and  17002  shows the retracted state. 
     In the push button unit  200 , the plurality of push buttons  20  are mounted on a base  52 , and the base  52  is raised and lowered by the elevating mechanism  51 . The shutter  31  opens and closes to the left and right, or up and down, and the ultraviolet irradiation unit  40  is installed on the back surface of the shutter  31 . Here again, the sensor unit  80  may be mounted and the disinfection operation may be executed at the desired timing. 
     Also, in the case of an elevator, for example, the disinfection operation may be executed when it is detected from the detection result of a weight sensor or the like that nobody is aboard. Also, in the case of a ticket vending machine comprising a touch panel, the disinfection operation may be executed after a ticket has been issued. The detection that nobody is aboard, and the completion of a ticket sale correspond to events that trigger a disinfection operation. 
     Also, a shutter unit comprising a three-dimensional shutter  101  provided with an ultraviolet irradiation unit  40  on the back surface and a shutter mechanism  32  for opening and closing the shutter  101  may be provided so as to be externally attached to an existing push button  20 . 
     The present invention is not limited to the embodiments given above, and various modifications are possible within the scope of the claims, and any embodiments obtained by suitably combining the technical means disclosed in different embodiments are also encompassed by the technical scope of the present invention.