Patent Publication Number: US-10312030-B2

Title: Illuminated keypad module with limited light leakage

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of China application serial no. 201710863656.X, filed on Sep. 22, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention is related to a keypad module, and particularly to a keypad module that can effectively improve light leakage. 
     Description of Related Art 
     Currently, a light-emitting keyboard or a light-emitting key are commonly seen. A light-emitting element is, for example, disposed on the light-emitting keyboard or the bottom of the light-emitting key. The light emitted by the light-emitting element can be transmitted through from a partially transparent keycap to achieve the visual effect. 
     However, in the known light-emitting keyboard or the light-emitting key, the light is not only transmitted through from a light transmitting portion of the keycap, but is also leaked from a gap under the keycap, which is glare that interferes user&#39;s view. It is an object for persons of the field to find out a solution to the light leakage problem mentioned above. 
     SUMMARY OF THE INVENTION 
     The invention provides a keypad module which may effectively improve light leakage. 
     In the invention, the keypad module includes a bottom plate, a circuit film, a plurality of barricades, an elastic body, a scissor mechanism and a keycap. The circuit film is disposed on the bottom plate and includes a switch. The barricades are disposed upright on the circuit film and surrounds the switch. The elastic body is disposed on the switch. The scissor mechanism is fixed on the bottom plate and disposed at a position close to the switch on the circuit film. The keycap is fixed on the scissor mechanism and covers the switch, the elastic body, the scissor mechanism and the barricades. 
     In an embodiment of the invention, the barricades are formed via punching the circuit film to be formed integrally with the circuit film. 
     In an embodiment of the invention, the keypad module further includes a soft light shielding film attached to the circuit film; the barricades are formed via punching the soft light shielding film. 
     In an embodiment of the invention, the keypad module further includes a frame structure disposed on the circuit film; the barricades are formed via punching an exterior finishing board. 
     In an embodiment of the invention, the keypad module further includes a frame structure disposed on the circuit film; the barricades are attached to the exterior finishing board. 
     In an embodiment of the invention, the keycap includes a top cover and a plurality of side walls connected to the top cover. The barricades respectively correspond to the side walls, and the height H 1  of each of the barricades satisfies: H 1 ≥H 2 −X*tan θ, wherein H 2  is a distance between the side wall corresponding to the barricades and the circuit film, X is a distance between a projection P 1  of the barricades with respect to the circuit film and a projection P 2  of the corresponding side wall with respect to the circuit film, and θ ranges from 0° to 60°. 
     In an embodiment of the invention, the θ ranges from 30° to 60°. 
     In an embodiment of the invention, the keycap moves between an initial position and a pressing position; the distance between each of the barricades and the top cover is larger than or equal to a distance difference between the initial position and the pressing position. 
     In an embodiment of the invention, the height of each of the barricades ranges from 0.5 mm to 1.2 mm. 
     In an embodiment of the invention, the thickness of each of the barricades ranges from 0.1 mm to 0.2 mm. 
     In summary, in the keypad module of the invention, with the configuration that the barricades are disposed upright on the circuit film, surround the switch and located in a range covered by the keycap, the possibility that the light is leaked from the gap between the side wall of the keycap and the circuit film can be reduced, thereby effectively solving the light leakage problem. 
     In order to make the aforementioned features and advantages of the disclosure more comprehensible, embodiments accompanying figures are described in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a keypad module according to an embodiment of the invention. 
         FIG. 2  is a schematic view illustrating that a keycap moves upward from the keypad module in  FIG. 1 . 
         FIG. 3  is a schematic explosive view of a light-emitting element and the keypad module in  FIG. 1 . 
         FIG. 4  is a cross-sectional view of the keycap of the keypad module in an initial position in  FIG. 1  taken along line A-A. 
         FIG. 5  is a schematic view illustrating that the keycap of the keypad module in  FIG. 4  moves to a pressing position. 
         FIG. 6  to  FIG. 8  are cross-sectional views of a plurality of keypad modules according to other embodiment of the invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 1  is a schematic view of a keypad module according to an embodiment of the invention.  FIG. 2  is a schematic view illustrating that a keycap moves upward from the keypad module in  FIG. 1 .  FIG. 3  is a schematic explosive view of a light-emitting element and the keypad module in  FIG. 1 . It should be indicated that, in the embodiment, a keypad module  100  is exemplified as a light-emitting keypad module.  FIG. 3  schematically illustrates the light-emitting element in dash lines under the keypad module  100 . The light-emitting element, for example, includes a light-emitting element  10  and a light-guide plate  20  so as to schematically illustrate a relative relationship between the light-emitting element and the keypad module  100 . Certainly, the configuration relationship between the keypad module  100  and the light-emitting element as well as the type of the light-emitting element are not limited to the illustration in FIG.  3 . 
     Referring to  FIG. 1  to  FIG. 3 , the keypad module  100  in the embodiment includes a bottom plate  110 , a circuit film  120 , a plurality of barricades  130 , an elastic body  140 , a scissor structure  150  and a keycap  160 . The circuit film  120  is disposed on the bottom plate  110  and includes a switch  122 . The barricades  130  are disposed upright on the circuit film  120  and surround the switch  122 . In the embodiment, the keypad module  100  includes four barricades  130 ; however, the invention provides no limitation to the number of the barricades  130 . 
     The elastic body  140  is disposed on the switch  122 . The elastic body  140  may be a metal dome, a rubber dome, a magnetic actuator or any element that can provide a pressing touch and restore the keycap  160 . The scissor mechanism  150  is fixed on the bottom plate  110  and disposed at a position close to the switch  122  on the circuit film  120  so as to enable the keycap  160  to move upward and downward stably. 
     The keycap  160  is fixed on the scissor mechanism  150 , and the keycap  160  covers the switch  122 , the elastic body  140 , the scissor mechanism  150  and the barricades  130 . The keycap  160  includes a top cover  162  and a plurality of side walls  164  connected to the top cover  162 . In the embodiment, the keycap  160  includes four side walls  164 . The fourth barricades  130  respectively correspond to the four side walls  164 . However, in other embodiment, the invention provides no particular limitation to the corresponding relationship between the barricades  130  and the side wall  164 . 
     In the embodiment, the keypad module  100  is provided with the configuration that the barricades  130  are disposed on the circuit film  120 , and the position at which the barricades  130  are disposed on the circuit film  120  is slightly retracted to the side wall  164  of the keycap  160  such that the top cover  162  of the keycap  160  can cover the barricades  130 . In this manner, the barricades  130  are not directly seen from the appearance of the keypad module  100 , and the keypad module  100  has an appearance similar to conventional keypad module. 
       FIG. 3  shows that a portion of the light emitted by the light-emitting element  10  can be transmitted to a light transmitting portion (not shown) on the keycap  160  to be emitted from the keycap  160  via the light-guide plate  20 , a hole on the bottom plate  110 , a hole on the circuit film  120  and a gap between the scissor mechanism  150  and the elastic body  140 . In the conventional keypad module, a portion of the light that is emitted from the light-emitting element is leaked from the light-guide plate, the hole on the bottom plate, the hole on the circuit film and the gap between the side wall of the keycap and the circuit film. However, in the keypad module  100  of the embodiment, the barricades  130  can cover the portion of the light so as to avoid that the light is leaked from the gap between the side wall  164  of the keycap  160  and the circuit film  120 , thereby effectively solving the light leakage problem. 
     It should be mentioned that, the embodiment simply illustrates a single keycap  160  and the corresponding switch  122 , the elastic body  140 , the scissor mechanism  150  and the barricades  130 . However, in the keypad module  100 , the number of the keycap  160  and the corresponding switch  122 , the elastic body  140 , the scissor mechanism  150  and the barricades  130  may be plural; the invention provides no limitation thereto. For example, the keypad module  100  may be disposed in the same manner as a keyboard. 
     In addition, generally speaking, when the user uses the keypad module  100 , the user&#39;s sight is laid on a position obliquely above the keypad module  100  instead of being parallel with the keypad module  100 . Therefore, the leaking light that is seen from the user&#39;s view is generally the light that is emitted toward the direction obliquely above the gap between the side wall  164  of the keycap  160  and the circuit film  120 . Therefore, if the light that is emitted toward the direction obliquely above the gap between the side wall  164  of the keycap  160  and the circuit film  120  can be blocked, the light leakage that causes discomfort to the user&#39;s eyes can be solved. In other words, in some embodiments, although the height H 1  (shown in  FIG. 4 ) of the barricades  130  may be the same as or larger than the size of the gap between the side wall  164  of the keycap  160  and the circuit film  120 , in some embodiments, the height H 1  of the barricades  130  may not be the same as or larger than the size of the gap between the side wall  164  of the keycap  160  and the circuit film  120 . The height H 1  of the barricades  130  may be set to be any value as long as the user at the position obliquely above the keycap module  100  does not see the leaking light when looking at the direction of the keypad module  100 . 
       FIG. 4  is a cross-sectional view of the keycap of the keypad module in an initial position in  FIG. 1  taken along line A-A.  FIG. 5  is a schematic view illustrating that the keycap of the keypad module in  FIG. 4  moves to a pressing position. It should be indicated that, in  FIG. 4  and  FIG. 5 , in order to illustrate the barricades  130  clearly, only the elements on the cross-section taken along line A-A are illustrated; the elements that are not on the cross-section are not shown. 
     Referring to  FIG. 4 , in the embodiment, the height H 1  of the barricades  130  satisfies H 1 ≥H 2 −X*tan θ, wherein H 2  is a distance between the side wall  164  corresponding to the barricades  130  and the circuit film  120 , X is a distance between a projection P 1  of the barricades  130  with respect to the circuit film  120  and a projection P 2  of the corresponding side wall  164  with respect to the circuit film  120 , and θ ranges from no 60°. More specifically, θ ranges from 30° to 60°, and θ is approximately an oblique angle between the user&#39;s eyes and the keypad module  100 . 
     In the embodiment, as long as the height H 1  of the barricades  130  satisfies the above-mentioned relationship, the possibility that the user at the position obliquely above the keypad module  100  sees the leaking light when looking at the direction of the keypad module  100  can be effectively reduced. In addition, in order to avoid that the height H 1  of the barricades  130  is over high and interferes the movement of the keycap  160 , in the embodiment, the distance between each of the barricades  130  and the top cover  162  is larger than or equal to a distance difference between the initial position (shown in  FIG. 4 ) and the pressing position (shown in  FIG. 5 ) so there is sufficient space for the keycap  160  to move. 
     Certainly, the invention provides no limitation to the relationship of the height H 1  of the barricades  130 . In terms of the keypad module  100  on conventional keyboard, the designer may directly set the height H 1  of the barricades  130  to range from 0.5 mm to 1.2 mm, which can also effectively reduce the possibility that the user sees leaking light. Certainly, the designer may adjust the height range and proportional relationship of the barricades  130 , the invention provides no limitation thereto. 
     In addition, in the embodiment, the thickness of the barricades  130  is exemplified in a range between 0.1 mm to 0.2 mm so that the structure of the barricades  130  can be configured upright stably in a limited space of the keycap  160 , and the thickness thereof is sufficient to cover the light. Similarly, the thickness of the barricades  130  is not limited thereto. 
     As shown in  FIG. 4 , in the embodiment, the barricades  130  are a portion of the circuit film  120 . In other words, the barricades  130  are formed by punching the circuit film  120 , and the barricades  130  and the circuit film  120  are formed integrally. Therefore, in the embodiment, a portion of the circuit film  120  serves as the switch  122  and the circuit electrically connected to the switch  122 , and another portion of the circuit film  120  is used for punching the barricades  130 , which is a simple structure. Certainly, the embodiment simply serves to illustrate a form of the barricades  130 , and the form of the barricades  130  is not limited thereto. 
       FIG. 6  to  FIG. 8  are cross-sectional views of a plurality of keypad modules according to other embodiments of the invention. It should be indicated that, in the following embodiments, the elements that are the same as or similar to those used in the previous embodiment are denoted by the same or similar reference numerals; no further descriptions are incorporated herein. The following paragraphs mainly discuss the differences between embodiments. 
     Referring to  FIG. 6  first, the major difference between a keypad module  100   a  in  FIG. 6  and the keypad module  100  in  FIG. 4  is that, in the embodiment, the keypad module  100   a  further includes a soft light shielding film  170   a . The soft light shielding film  170   a  is exemplified as a MYLAR, and the material thereof is a polyester resin which can be easily punched to form a particular shape and provides a certain degree of supporting force. In the embodiment, by punching to form the barricades  130  on the soft light shielding film  170   a , and the soft light shielding film  170   a  is attached to the circuit film  120 , the barricades  130  that is established upright on the circuit film  120  can be formed, and the fabrication process is simple. 
     Referring to  FIG. 7 , the major difference between a keypad module  100   b  in  FIG. 7  and the keypad module  100  in  FIG. 4  is that, in the embodiment, the keypad module  100   b  further includes a frame structure  180   b  disposed on the circuit film  120 . The barricades  130  are formed by punching the frame structure  180   b . In other words, in the embodiment, the fabrication method of the keypad module  100   b  is to punch the frame structure  180   b  or inject the barricades  130 , and then the frame structure  180   b  is assembled on the circuit film  120 . In the embodiment, the frame structure  180   b  is exemplified as an exterior finishing board. The frame structure  180   b  not only has a decorative effect, and the barricades  130  thereof also cover the leaking light, and thus a good visual effect can be provided. Certainly, the invention provides no limitation to the type of the frame structure  180   b.    
     Referring to  FIG. 8 , the major difference between a keypad module  100   c  in  FIG. 8  and the keypad module  100   b  in  FIG. 7  is that, in the embodiment, the barricades  130  are, for example, formed on the soft light shielding film  170   a  first as shown in  FIG. 6 . In other words, for example, the barricades  130  are formed by punching on the soft light shielding film  170   a  first, and then the soft light shielding film  170   a  having the barricades  130  is attached to the frame structure  180   c , unlike in  FIG. 7  in which the barricades  130  are formed by a portion of the frame structure  180   b . It should be mentioned that a plurality of focus of the barricades  130  are described above, but the form of the barricades  130  are not limited thereto. The barricades  130  fall within the scope claimed by the invention as long as the barricades can reduce the possibility that the light is leaked from the gap between the side wall  164  of the keypad  160  and the circuit film  120 . 
     In summary, in the keypad module of the invention, with the configuration that the barricade is established upright on the circuit film, surrounds the switch and located within a range covered by the keycap, the possibility that light is leaked from the gap between the side wall of the keycap and the circuit film can be reduced, thereby effectively solving the light leakage problem. In addition, the height H 1  of the barricades satisfies H 1 ≥H 2 −X*tan θ, wherein H 2  is a distance between the side wall corresponding to the barricades and the circuit film, X is a distance between the projection P 1  of the barricades with respect to the circuit film and the projection P 2  of the corresponding side wall with respect to the circuit film; in this manner, the possibility that the user (at the position obliquely above the keypad module) sees the leaking light when looking at the direction of the keypad module can be effectively reduced. 
     Although the invention has been disclosed by the above embodiments, the embodiments are not intended to limit the invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the invention without departing from the scope or spirit of the invention. Therefore, the protecting range of the invention falls in the appended claims.