Patent Publication Number: US-2018053610-A1

Title: Lumnious keyboard

Description:
FIELD OF THE INVENTION 
     The present invention relates to a luminous keyboard, and more particularly to a luminous keyboard capable of avoiding light leakage from rims of key structures. 
     BACKGROUND OF THE INVENTION 
     As known, keyboards are indispensable input devices for people in the modern societies. Generally, plural keys are installed on a top surface of the keyboard. Via the keyboard, the user can press one or more keys to input a command. 
     With increasing development of keyboards, a keyboard with a backlight module has been prevailing in the market. The keyboard with the backlight module is also referred as a luminous keyboard. When the luminous keyboard is used in an indoor lighting environment such as an office or a room, the human eyes can obviously recognize that the light beams from a bottom side of the luminous keyboard illuminate all keys of the luminous keyboard. Consequently, a visual effect is generated. 
     However, the conventional luminous keyboard still has some drawbacks. For example, the light beams are not only transmissible through the light-transmissible zones of all keys but also leaked from the vacant spaces between adjacent keys. The portions of the light beams leaked from the vacant spaces between adjacent keys are stray light that interferes with the vision line of the user. The stray light is undesired. 
     Therefore, the conventional luminous keyboard needs to be further improved. 
     SUMMARY OF THE INVENTION 
     The present invention provides a luminous keyboard. The luminous keyboard includes a light guide plate, and plural elongated condenser structures are formed on a top surface of the light guide plate. By the elongated condenser structures, the beam angles of the light beams from the light guide plate are converged and the light beams are concentrated. Consequently, the light beams do not leak from the vacant spaces between adjacent key structures. 
     In accordance with an aspect of the present invention, there is provided a luminous keyboard. The luminous keyboard includes plural key structures, a light guide module and a shielding plate. Each of the plural key structures includes a keycap, a movable triggering mechanism, a membrane circuit board and a supporting plate. The movable triggering mechanism is disposed under the keycap and connected with the keycap. The membrane circuit board is disposed under the movable triggering mechanism. The membrane circuit board is triggered by the movable triggering mechanism when the movable triggering mechanism receives an external pressing force from the keycap. The supporting plate is disposed under the membrane circuit board. The movable triggering mechanism is penetrated through the membrane circuit board and movably coupled with the supporting plate. The light guide module is disposed under the supporting plate, and includes a light source and a light guide plate. Moreover, plural elongated condenser structures are formed on a top surface of the light guide plate. The light source emits plural light beams into the light guide plate. The plural light beams travel within the light guide plate and pass through the plural elongated condenser structures. Each of the plural elongated condenser structures has a long axial direction. The plural elongated condenser structures are distributed in parallel and along a direction perpendicular to the long axial direction. The shielding plate is arranged between the supporting plate and the light guide plate. The shielding plate includes plural openings, and the plural openings are aligned with the corresponding keycaps. A vacant space between every two adjacent key structures is sheltered by the shielding plate. After the light beams pass through the elongated condenser structures, beam angles of the light beams are converged. Moreover, first portions of the light beams are reflected back to the light guide plate by the shielding plate, and the first portions of the light beams travel to the plural keycaps through the plural openings. Moreover, second portions of the light beams are not reflected by the shielding plate, and the second portions of the light beams travel to the plural keycaps through the plural openings. The top surface of the light guide plate is a smooth surface. 
     In an embodiment, the elongated condenser structures are V-cut structures. The V-cut structures are formed on the top surface of the light guide plate and arranged in parallel with each other. 
     In an embodiment, movable triggering mechanism includes a scissors-type connecting element and a rubbery elastomer. The scissors-type connecting element has a first end and a second end opposed to the first end. The first end of the scissors-type connecting element is connected with the keycap. The second end of the scissors-type connecting element is penetrated through plural through-holes of the membrane circuit board and connected with the supporting plate. The movable triggering mechanism has an accommodation space. The rubbery elastomer is disposed within the accommodation space. An end of the rubbery elastomer is contacted with the membrane circuit board. 
     In an embodiment, the supporting plate includes plural perforations, and at least portions of the perforations are aligned with the corresponding through-holes. After the second portions of the light beams leave the elongated condenser structures, the second portions of the light beams pass through the openings of the shielding plate, the perforations of the supporting plate and the through-holes of the membrane circuit board sequentially and travel to the keycaps of the plural key structures. 
     In an embodiment, the light guide plate includes a light guide substrate and a brightness enhancement film. The brightness enhancement film is stacked over the light guide substrate. The plural elongated condenser structures are formed on the brightness enhancement film. 
     In an embodiment, the light guide plate includes a light guide substrate, a first brightness enhancement film and a second brightness enhancement film. The first brightness enhancement film and the second brightness enhancement film are stacked over the light guide substrate. The elongated condenser structures include plural first elongated condenser structures and plural second elongated condenser structures. The plural first elongated condenser structures are formed on a top surface of the first brightness enhancement film. The plural second elongated condenser structures are formed on the second brightness enhancement film. 
     In an embodiment, the plural first elongated condenser structures on the first brightness enhancement film are arranged along a first direction and in parallel with each other, and the plural second elongated condenser structures on the second brightness enhancement film are arranged along a second direction and in parallel with each other. The first direction is in parallel with the second direction, or the first direction and the second direction intersect each other. 
     In an embodiment, the luminous keyboard further includes a fame body. The plural key structures are exposed through the frame body. The light guide module is sheltered by the frame body. 
     The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view illustrating the appearance of a luminous keyboard according to an embodiment of the present invention; 
         FIG. 2  is a schematic perspective view illustrating a single key structure of the luminous keyboard according to the embodiment of the present invention; 
         FIG. 3  is a schematic exploded view illustrating the single key structure of the luminous keyboard according to the embodiment of the present invention; 
         FIG. 4  is a schematic cross-sectional view illustrating the single key structure of the luminous keyboard according to the embodiment of the present invention; 
         FIG. 5  is an enlarged fragmentary perspective view illustrating the light guide plate of the luminous keyboard according to the embodiment of the present invention; 
         FIG. 6  is an enlarged fragmentary perspective view illustrating a variant example of the light guide plate of the luminous keyboard, in which the light guide plate comprises a light guide substrate and a brightness enhancement film; 
         FIG. 7  is an enlarged fragmentary perspective view illustrating another variant example of the light guide plate of the luminous keyboard, in which the light guide plate comprises a light guide substrate and two brightness enhancement film; and 
         FIG. 8  is an enlarged fragmentary perspective view illustrating a further variant example of the light guide plate of the luminous keyboard, in which the light guide plate comprises a light guide substrate and two brightness enhancement film. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  is a schematic perspective view illustrating the appearance of a luminous keyboard according to an embodiment of the present invention.  FIG. 2  is a schematic perspective view illustrating a single key structure of the luminous keyboard according to the embodiment of the present invention.  FIG. 3  is a schematic exploded view illustrating the single key structure of the luminous keyboard according to the embodiment of the present invention. As shown in  FIGS. 1, 2 and 3 , the luminous keyboard  1  comprises plural key structures  11 , a shielding plate  12 , a light guide module  13  and a frame body  14 . The light guide module  13  is sheltered by the frame body  14 , and the plural key structures  11  are exposed to the outside through the frame body  14 . 
     Please refer to  FIGS. 2 and 3  again. The light guide module  13  emits light beams. The light beams pass through an opening  12   a  of the shielding plate  12 , and the light beams are guided upwardly to pass through the key structure  11 . The components of the key structure  11  will be described later. The light guide module  13  is the source of emitting the light beams. In an embodiment, the light guide module  13  comprises a light source  130  and a light guide plate  131 . The light source  130  emits the light beams to the light guide plate  131 . After the light beams  130  are guided by the light guide plate  131  to travel within the light guide plate  131  for a specified distance, the light beams leave the light guide plate  131  and travel in the direction toward the key structure  11 . A keycap  110  of the key structure  11  has at least one light-transmissible zone  1105 . The light-transmissible zone  1105  is made of a light-transmissible material. The light beams pass through the light-transmissible zone  1105  to illuminate the luminous keyboard  1 . 
     For well guiding the light beams to the key structure  11 , the shielding plate  12  is arranged between a supporting plate  113  of the key structure  11  and the light guide plate  131 . Consequently, the light beams are guided to be travel upwardly to the key structure  11 . After the light beams pass through the keycap  110 , the key structure  11  is illuminated. In more detail, the light-outputting position of the light guide plate  131  is determined according to the position of the opening  12   a  of the shielding plate  12 . The opening  12   a  of the shielding plate  12  is aligned with the keycap  110 . That is, the opening  12   a  of the shielding plate  12  is disposed under the keycap  110 . After the light beams pass through the opening  12   a , the light beams travel to the keycap  110 . Moreover, a vacant space between every two adjacent key structures  11  is sheltered by the shielding plate  12 . Consequently, portions of the light beams that travel to the vacant space are reflected back to the light guide plate  131  by the shielding plate  12 . Since the light beams are shaded and reflected by the shielding plate  12 , the light beams do not leak to the outside through the vacant space. 
       FIG. 4  is a schematic cross-sectional view illustrating the single key structure of the luminous keyboard according to the embodiment of the present invention. Please refer to the  FIGS. 3 and 4 . As mentioned above, the opening  12   a  of the shielding plate  12  is disposed under the keycap  110 . In addition, the area of the opening  12   a  of the shielding plate  12  is smaller than the area of the keycap  110 . From a top view of the keycap  110 , the light beams passing through the opening  12   a  are shaded by the cross section  110  of the keycap  110 . This is the basic structure of the luminous keyboard for avoiding light leakage from the rims of the key structures. Moreover, due to the physical properties of the light guide plate  131  and the light beams, the light-outputting directions of the light beams from the light guide plate  131  are not completely perpendicular to the surface of the light guide plate  131 . That is, when the light beams leave the light guide plate  131 , the light beams deflect at a beam deflection angle. If the beam deflection angle is too large, the light leakage problem possibly occurs. For solving the light leakage problem, the light guide plate  131  is specially designed. In an embodiment, plural elongated condenser structures  1312  are formed on a top surface of the light guide plate  131 . The plural elongated condenser structures  1312  are contiguously arranged side by side. Preferably, the plural elongated condenser structures  1312  are arranged side by side and in parallel with each other. After the light beams travelling within these light guide plate  131  pass through the elongated condenser structures  1312 , these light beams are converged. Since the beam angles of these light beams are corrected, the light-outputting directions of the light beams are nearly perpendicular to the surface of the light guide plate  131 . That is, the light-outputting directions of the light beams are nearly in parallel with a normal direction of the light guide plate  131 . Since the light-outputting position of the light guide plate  131  is determined according to the position of the opening  12   a  of the shielding plate  12 , the light beams outputted from the light guide plate  131  are only permitted to travel upwardly through the opening  12   a . The beam angle “a” of the light beams passing through the opening  12   a  is smaller than the included angle “b” between a line passing through the rim of the opening  12   a  and the rim of the keycap  110  and the shielding plate  12 . Since the optical paths of the light beams are not beyond the line passing through the rim of the opening  12   a  and the rim of the keycap  110 , the light-outputting directions of the light beams are limited. Consequently, the light leakage from the rim of the key structure is avoided. 
       FIG. 5  is an enlarged fragmentary perspective view illustrating the light guide plate of the luminous keyboard according to the embodiment of the present invention. Each elongated condenser structure  1312  has a semi-cylindrical shape. Moreover, each elongated condenser structure  1312  has a long axial direction P. In a coordinate system, the long axial direction P is in parallel with a Y axial direction. Moreover, the plural elongated condenser structures  1312  are arranged in parallel with each other along an X axial direction of the coordinate system, which is perpendicular to the long axial direction P. In an embodiment, the elongated condenser structures  1312  are V-cut structures, formed on a top surface  1311  of the light guide plate  131 , and arranged in parallel with each other along the X axial direction. From a side view, the plural elongated condenser structures  1312  are contiguously arranged side by side to collaboratively form a wavy profile. Preferably, the top surface  1311  of the light guide plate  131  is a smooth surface. Consequently, the efficacy of reducing the scattered light and the efficacy of condensing the light are enhanced. 
     Hereinafter, the key structure  11  will be illustrated. Please refer to  FIGS. 3 and 4  again. Each key structure  11  comprises the keycap  110 , a movable triggering mechanism  111 , a membrane circuit board  112  and a supporting plate  113 . The movable triggering mechanism  111  is disposed under the keycap  110 . The membrane circuit board  112  is disposed under the movable triggering mechanism  111 . That is, two opposite ends of the movable triggering mechanism  111  are connected with the keycap  110  and the membrane circuit board  112 , respectively. When an external pressing force exerted on the keycap  110  is received by the movable triggering mechanism  111 , the membrane circuit board  112  is triggered by the movable triggering mechanism  111 . 
     The supporting plate  113  is disposed under the membrane circuit board  112 . The movable triggering mechanism  111  is penetrated through the membrane circuit board  112 , and movably coupled with the supporting plate  113 . The movable triggering mechanism  111  comprises a scissors-type connecting element  1111  and a rubbery elastomer  1112 . The movable triggering mechanism  111  comprises a first end  1111   a  and a second end  1111   b , which are opposed to each other. The first end  1111   a  is connected with the keycap  110 . The second end  1111   b  is penetrated through plural through-holes  112   a  of the membrane circuit board  112  and connected with the supporting plate  113 . The movable triggering mechanism  111  has an accommodation space  1111   c . The rubbery elastomer  1112  is disposed within the accommodation space  1111   c . An end of the rubbery elastomer  1112  is contacted with the membrane circuit board  112  and disposed on the membrane circuit board  112 . When an external pressing force is exerted on the keycap  110 , the scissors-type connecting element  1111  and the rubbery elastomer  1112  are pushed by the keycap  110 . Consequently, the membrane circuit board  112  is triggered by the rubbery elastomer  1112 . 
     The supporting plate  113  has plural perforations  113   a  along the optical paths of the light beams. At least portions of the perforations  113   a  are aligned with the corresponding through-hole  112   a . After the light beams leave the elongated condenser structures  1312 , the light beams pass through the openings  12   a  of the shielding plate  12 , the perforations  113   a  of the supporting plate  113 , the through-holes  112   a  of the membrane circuit board  112  and the scissors-type connecting element  1111  sequentially and travel to the keycap  110 . 
     It is noted that numerous modifications and alterations may be made while retaining the teachings of the invention. Some examples of the light guide plate  131  will be illustrated with reference to  FIGS. 6, 7 and 8 . 
       FIG. 6  is an enlarged fragmentary perspective view illustrating a variant example of the light guide plate of the luminous keyboard, in which the light guide plate comprises a light guide substrate and a brightness enhancement film. As shown in  FIG. 6 , the light guide plate  231  comprises a light guide substrate  2310  and a brightness enhancement film  2311 . Moreover, plural elongated condenser structures  2311   a  are formed on the brightness enhancement film  2311 . The brightness enhancement film  2311  is stacked over the light guide substrate  2310 . Similarly, the light guide plate  231  of  FIG. 6  also has the light-condensing function. 
       FIG. 7  is an enlarged fragmentary perspective view illustrating another variant example of the light guide plate of the luminous keyboard, in which the light guide plate comprises a light guide substrate and two brightness enhancement film. As shown in  FIG. 7 , the light guide plate  331  comprises a light guide substrate  3310 , a first brightness enhancement film  3311  and a second brightness enhancement film  3312 . The first brightness enhancement film  3311  and the second brightness enhancement film  3312  are stacked over the light guide substrate  3310 . Moreover, plural first elongated condenser structures  3311   a  are formed on the first brightness enhancement film  3311 , and plural second elongated condenser structures  3312   a  are formed on the second brightness enhancement film  3312 . The arranging direction of the plural first elongated condenser structures  3311   a  and the arranging direction of the plural second elongated condenser structures  3312   a  are identical. That is, the plural first elongated condenser structures  3311   a  and the plural second elongated condenser structures  3312   a  are in parallel with each other. Since the light guide plate  331  of  FIG. 7  comprises first brightness enhancement film  3311  and the second brightness enhancement film  3312  to condense the light beams twice, the light-condensing efficacy is further enhanced. 
       FIG. 8  is an enlarged fragmentary perspective view illustrating a further variant example of the light guide plate of the luminous keyboard, in which the light guide plate comprises a light guide substrate and two brightness enhancement film. As shown in  FIG. 8 , the light guide plate  431  comprises a light guide substrate  4310 , a first brightness enhancement film  4311  and a second brightness enhancement film  4312 . The first brightness enhancement film  4311  and the second brightness enhancement film  4312  are stacked over the light guide substrate  4310 . Moreover, plural first elongated condenser structures  4311   a  are formed on the first brightness enhancement film  4311 , and plural second elongated condenser structures  4312   a  are formed on the second brightness enhancement film  4312 . There is an included angle between the arranging direction of the plural first elongated condenser structures  4311   a  and the arranging direction of the plural second elongated condenser structures  4312   a . Preferably, the plural first elongated condenser structures  4311   a  and the plural second elongated condenser structures  4312   a  are perpendicular to each other. Since the light guide plate  431  of  FIG. 8  comprises first brightness enhancement film  4311  and the second brightness enhancement film  4312  to condense the light beams twice, the light-condensing efficacy is further enhanced. 
     From the above descriptions, the present invention provides the luminous keyboard. The plural elongated condenser structures are formed on the top surface of the light guide plate and contiguously arranged side by side. By the elongated condenser structures, the beam angles of the light beams from the light guide plate are converged and the light beams are concentrated. Consequently, the brightness of the backlight is increased. Since the light beams do not leak from the vacant spaces between adjacent key structures, the vision line of the user is not interfered. Moreover, since the light beams are outputted from the surfaces of the key structures only, the brightness of the backlight is increased. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all modifications and similar structures.