Abstract:
The invention provides an optical touch device, including a main body, a keyboard and a light emitting member. The keyboard, placed on the main body and having a first end portion and a second end portion, includes a supporting frame, a keycap and a stopping member. The keycap is connected to the supporting frame and moves between a first position and a second position. The stopping member is connected to the keycap and moves simultaneously with the keycap. The light emitting member generates a light beam to the keyboard. When the keycap is in the first position, the light beam passes through the first end portion to the second end portion, and when the keycap is in the second position, the light beam is terminated by the stopping member, such that the light does not reach the second end portion.

Description:
This Application claims priority of Taiwan Patent Application No. 098111353, filed on Apr. 6, 2009, the entirety of which is incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a keyboard, and in particular, to a keyboard applied for an optical touch device. 
     2. Description of the Related Art 
     Keyboards are important for computer systems as an input tool. Usually, keyboards are manufactured by multiple components, such as plastic keypads, tact switches, circuit board and so on, resulting in a complicated structure with fixed costs. Thus, one method to further decrease keyboard costs is to simplify its structure and decrease required components. 
     A virtual keyboard has been disclosed, utilizing a touch panel. A user directly touches the panel to operate the virtual keyboard. However, a drawback of the virtual keyboard includes users being unable to feel the physical keys of the virtual keyboard so that viewing for position is required for input, thus reducing input speed and causing eyestrain. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention provides a keyboard comprising a supporting frame, a keycap and a stopping member. The supporting frame is pervious to light. The keycap is connected to the supporting frame. The stopping member is connected to the keycap and is not pervious to light or opaque. The keycap moves between a first position and a second position. When the keycap is in the first position, the stopping member and the supporting frame are on different horizontals, and when the keycap is in the second position, the stopping member and the supporting frame are on the same horizontal. 
     The invention provides another keyboard having a first end portion and a second end portion. The keyboard comprises a supporting frame, a keycap and a stopping member. The supporting frame is pervious to light. The keycap is connected to the supporting frame and moves between a first position and a second position. The stopping member is connected to the keycap and is not pervious to light or opaque. When the keycap is in the first position, a light beam passes through the first end portion to the supporting frame to the second end portion, and when the keycap is in the second position, the light beam is terminated by the stopping member, such that the light beam does not reach the second end portion. 
     The invention provides an optical touch device, comprising a main body, a keyboard and a light emitting member. The keyboard, placed on the main body and having a first end portion and a second end portion, comprises a supporting frame, a keycap and a stopping member. The keycap is connected to the supporting frame and moves between a first position and a second position. The stopping member is connected to the keycap and moves simultaneously with the keycap. The light emitting member generates a light beam to the keyboard. When the keycap is in the first position, the light beam passes through the first end portion to the second end portion, and when the keycap is in the second position, the light beam is terminated by the stopping member, such that the light does not reach the second end portion. 
     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  is an exploded view of an optical touch device of the invention; 
         FIG. 2A  is a plan view of the optical touch device of the invention; 
         FIG. 2B  is an elevational view of the optical touch device in  FIG. 2A ; 
         FIGS. 3A and 3B  are sectional views along a line A-A′ in  FIG. 2A ; and 
         FIGS. 4A and 4B  are sectional views showing variant embodiments of the keycap in  FIGS. 3A and 3B . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIG. 1 , the invention provides an optical touch device  100  comprising an optical touch panel  200 , a keyboard  300 , a reflective strip  500  (or a reflector) and two optical lens modules  400  respectively disposed on two adjacent points of the optical touch panel  200 . The optical lens module  400  comprises a light emitting member and a light sensor. The optical touch device  100  utilizes the light emitting member of the optical lens module  400  to emit a light beam E and detect the reflected light beam E when the light beam E reaches the reflective strip  500  and is reflected therefrom along its original path. Therefore, when an object or a finger touches a position on a surface of the optical touch panel  200 , the light sensor detects a signal of which the light beam is shown to be blocked. Thereby, the touched position on the optical touch panel  200  then can be determined by a processing system according to the blocked point. 
     Referring to  FIG. 2A  and  FIG. 2B , the keyboard  300  comprises a supporting frame  310 , a plurality of keycaps  320  and a plurality of stopping member  330 , wherein the supporting frame  310 , the keycaps  320  and the stopping member  330  are integrally formed by rubber. 
     The supporting frame  310  is pervious to light, such that the light beam E from the light emitting member is able to pass through the keyboard  300  to the reflective strip  500 , and then is reflected back to the optical sensor. The supporting frame  310  comprises a plurality of supporting members  311  (pervious to light) and the plurality of keycaps  320  are connected to the supporting members  311 . Moreover, when the keyboard  300  is placed on the optical touch panel  200 , the supporting members  311  abut the optical touch panel  200  thus support the keycap  320 , and thereby a distance is kept between the keycaps  320  and the optical touch panel  200 . 
     It should be noted that in the embodiment, the plurality of supporting members  311  are rectangular in shape and arranged in parallel with each other, but the shape and the arrangement of the supporting members  311  are not limited thereto, wherein the keycaps  320  are only required to be supported thereby. 
     Referring to  FIG. 3A  and  FIG. 3B , the keycap  320  is able to moves between a first position (position before being pressed, as shown in  FIG. 3A ) and a second position (position after being pressed, as shown in  FIG. 3B ). Each keycap  320  has an inner surface S. Each keycap  320  is provided a stopping member  330  which moves simultaneously with the keycap  320 . The stopping member  330  comprises a protrusion  331  and a layer  332 . The protrusion  331 , protruded from the inner surface S, is integrally formed with the keycap  320  as a single piece. The layer  332  is formed on the protrusion  331  and is not pervious to light(opaque), or may absorb light to block the light beam. In an embodiment, the layer  332  is a grinding layer, which is formed integrally on the keycap  320  by grinding the inner surface S in order to be not pervious to light. Otherwise, a coating layer or a sputtering layer is formed on the inner surface S to make the layer  322  not pervious to light. Note that the method of forming a layer not pervious to light is not limited thereto, and only requires that the layer  332  is not pervious to light. In an embodiment, the whole stopping member  330  (the protrusion  331  and the layer  332 ) is made of material not pervious to light, and then is adhered on the inner surface S of the keycap  320 . In another embodiment, the protrusion  331  of the stopping member  330  is integrally formed with the keycap  320 , and then the layer  332  of the stopping member  330 , made of opaque material (not pervious to light), is adhered on the inner surface S of the keycap  320 . 
     Referring to  FIGS. 4A and 4B , in a variant embodiment, the keycap  320  is able to move between a first position (position before being pressed, as shown in  FIG. 4A ) and a second position (position after being pressed, as shown in  FIG. 4B ), wherein the stopping member  330 ′ is a layer directly formed on the inner surface S of the keycap  320 . Specifically, the layer  330 ′ is a grinding layer, which is formed integrally on the keycap  320  by grinding the inner surface S. Otherwise, a coating layer or a sputtering layer is formed on the inner surface S, but it is not limited thereto as long as the inner surface S is not pervious to light or opaque. 
     Referring to  FIGS. 3A and 4A , when the keycap  320  is in the first position (position before being pressed), the bottom of the stopping member  330 ,  330 ′ and that of the supporting frame  310  are at different horizontals. Referring to  FIGS. 3B and 4B , when the keycap  320  is pressed down to move from the first position to the second position (position after being pressed), the bottom of stopping member  330 ,  330 ′ and that of the supporting frame  310  are at the same horizontal. 
     Referring to  FIGS. 2A ,  2 B,  3 A,  3 B,  4 A and  4 B again, as shown in  FIG. 2A , the keyboard  300 , placed on the optical touch panel  200 , has a first end portion P 1  and a second end portion P 2  opposite thereto. The optical lens module  400  is disposed on the two adjacent corners of the optical touch panel  200 , and provides a light beam E to detect whether there are fingers or objects touching the surface of the optical touch panel  200 . As shown in  FIGS. 3A and 4A , when the keycap  320  is in the first position, the light beam E successfully passes through the supporting members  311 , from the first end portion P 1  to the second end portion P 2 , to reach the reflective strip  500  because the supporting frame  310  and the supporting members  311  are pervious to light. As shown in  FIGS. 3B and 4B , when the user presses the keycap  320  from the first position to the second position, allowing the stopping member  330 ,  330 ′ and the supporting frame  310  to be on the same horizontal, the light beam E is stopped by the stopping member  330 ,  330 ′ which is not pervious to light, such that the light beam E is not able to pass through the stopping member  330 ,  330  to reach the second end portion P 2  and the reflective strip  500  as well. Meanwhile, a blocked point would be detected and used to obtain the location of the pressed down keycap  320 . 
     As described, before the user presses down the keycap  320 , the light beam E successfully passes through the keyboard  300  to reach the reflective strip  500  and be reflected thereby. The situation is like that there is not any contact point on the conventional optical touch panel. After the user presses down the keycap  320 , due to the stopping ability of the stopping member  330 ,  330 ′, the light beam E can not reach the reflective strip  500 . Therefore, a blocked point is detected by the optical sensor, and this situation is like that there is a contact point on the conventional optical touch panel. 
     Referring to  FIG. 1 , in an embodiment, a virtual keyboard  600  can be display in the optical touch panel  200 . When the keyboard  300  is placed on the optical touch panel  200 , the keyboard  300  corresponds to the virtual keyboard  600 . That is, the keycaps  320  of the keyboard  300  corresponds to the keys of the virtual keyboard  600 , respectively. As a result, after the user presses down a specific keycap, the corresponding key of the virtual keyboard  600  is touched, and a corresponding function is performed. In an embodiment, no virtual keyboard is displayed in the optical touch panel  200 , but location data of the contact points for each keycaps  320  on the optical touch panel is predetermined and stored (i.e. locations of the blocked points). For example, when a specific keycap is pressed down, the specific keycap may be determined according to the location of a blocked point corresponding to the specific keycap, and the function of the pressed keycap may be performed. 
     The keyboard  300  of the invention can be applied in any optical touch device. When a user needs to use a physical keyboard, the keyboard  300  can be placed on the optical touch panel to be operated, providing real touch feeling without affecting the operation of the optical touch device. Additionally, the keyboard  300  is formed integrally by soft material, thus the keyboard  300  can be folded in any manner, which is convenient for users to carry. Moreover, the keyboard  300  has a simple structure and low material cost. 
     While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.