Patent Publication Number: US-2012032887-A1

Title: Touch keyboard and electronic device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 99126117, filed on Aug. 5, 2010. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     1. Field of the Invention 
     The invention relates to a keyboard and an electronic device using the same. Particularly, the invention relates to a touch keyboard and an electronic device using the same. 
     2. Description of Related Art 
     With the coming era of information explosion, efficiency for processing and providing information becomes essential. In this case, a good keyboard design may avail improving the efficiency for processing and providing information. 
     To improve the efficiency, a number of keys of the keyboard of a computer or a notebook computer is up to about 100, and different key position configurations are designed to satisfy habits of different users, language habits of different nations, and utilization requirements of different usages. For example, a key number of a Japanese standard keyboard is more than that of an American standard keyboard, and configuration positions of the keys are also different. Since a conventional computer keyboard is a physical keyboard, a manufacturer generally manufactures different keyboards to satisfy habits of different users, language habits of different nations, and utilization requirements of different usages. Once such kind of keyboard is manufactured, it cannot be changed to other keyboard configurations, which is inconvenient in inventory management. Moreover, a user generally selects a favorite keyboard configuration when purchasing a keyboard, and once the keyboard is purchased, the keyboard configuration cannot be changed. Such problem is more obvious for a notebook computer. For example, if the user considers that the keyboard configuration does not match his utilization habit after purchasing the notebook computer, the user has to replace the notebook computer in order to thoroughly resolve such problem, though it is quite impracticable. Moreover, if the notebook computers using the American standard keyboards are sold to Japan, a sales volume thereof is influenced due to that the keyboard configuration does not match the Japanese utilization habit. 
     Moreover, since the conventional keyboard applies physical keys, limited by heights of the keys, a thickness of the conventional keyboard is hard to be effectively reduced, so that a thickness of the notebook computer is hard to be reduced. In addition, since external liquid is easy to infiltrate the keyboard from fissures between the physical keys to short-circuit a circuit board therein, a waterproof function of the conventional keyboard is hard to be implemented. 
     Keyboards disclosed by U.S. Patent Publication Nos. 20080225006 and 20100103116, a Taiwan Patent No. 1236239 and a Taiwan Patent Publication No. 200816023 are all physical keyboards. Keyboards disclosed by U.S. Pat. Nos. 6,510,048 and 7,719,826 are detachable. Taiwan Patent No. M358363, a Taiwan Patent Publication No. 200943139, U.S. Pat. Nos. 6,844,539, 7,355,594, and 7,573,465 and U.S. Patent Publication No. 20030234346 and 20100090986 respectively disclose a touch device. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a touch keyboard, the touch keyboard has a thin thickness and a light weight. 
     The invention is directed to an electronic device, the electronic device has a thin thickness and a light weight. 
     Additional aspects and advantages of the invention will be set forth in the description of the techniques disclosed in the invention. 
     To achieve one of or all aforementioned and other advantages, an embodiment of the invention provides a touch keyboard including a keyboard pattern and a touch module. A sensing space is located in front of the keyboard pattern. The touch module is disposed at periphery of the keyboard pattern. The touch module includes at least one light emitting element, at least one light guide unit, and at least one optical detector. The light emitting element is disposed beside the keyboard pattern and capable of emitting a light beam. The light guide unit is disposed at a side of the keyboard pattern. The light guide unit has a first surface, a second surface opposite to the first surface, and a light incident surface connected to the first surface and the second surface. The light beam from the light emitting element is capable of entering the light guide unit through the light incident surface and capable of being transmitted to the sensing space through the first surface. The optical detector is disposed beside the sensing space for sensing the light beam from the sensing space. 
     Another embodiment of the invention provides an electronic device including a screen, a base, and the aforementioned touch keyboard. The screen has a display area, and the display area is capable of displaying a dynamic image frame. The base is connected to the screen, and the touch keyboard is disposed on the base. 
     The embodiments of the invention may achieve at least one of the following effects. The touch keyboard and the electronic device according to the embodiments of the invention may use the optical detector to detect a touch operation of a user, so that a thickness of the touch keyboard is relatively thin, and a weight thereof is relatively light. Accordingly, the electronic device according to the embodiment of the invention may have a small size and a light weight. 
     Other objectives, features and advantages of the invention will be further understood from the further technological features disclosed by the embodiments of the invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1A  is a three-dimensional view of an electronic device according to an embodiment of the invention. 
         FIG. 1B  is an exploded view of an electronic device of  FIG. 1A . 
         FIG. 2A  is a three-dimensional view of a carrier board, a light emitting device, a light guide unit, and a reflection unit of  FIG. 1B . 
         FIG. 2B  is an enlarged view of a region R of  FIG. 2A . 
         FIG. 3  is a cross-sectional view of a carrier board and a light guide unit of  FIG. 1B  along an I-I line. 
         FIG. 4  is a front view of a touch module and a keyboard pattern of  FIG. 1B . 
         FIG. 5  is a block diagram of a touch module of  FIG. 1A . 
         FIG. 6  is an operation flowchart of a control unit. 
         FIG. 7  is an exploded view of an electronic device according to another embodiment of the invention. 
         FIG. 8  is a three-dimensional view of a reversed touch keyboard of  FIG. 7 . 
         FIG. 9  is a cross-sectional view of a touch keyboard of  FIG. 7  along an II-II line. 
         FIG. 10  is a three-dimensional view of an electronic device according to still another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” etc., is used with reference to the orientation of the Figure(s) being described. The components of the invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. On the other hand, the drawings are only schematic and the sizes of components may be exaggerated for clarity. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Similarly, the terms “facing,” “faces” and variations thereof herein are used broadly and encompass direct and indirect facing, and “adjacent to” and variations thereof herein are used broadly and encompass directly and indirectly “adjacent to”. Therefore, the description of “A” component facing “B” component herein may contain the situations that “A” component directly faces “B” component or one or more additional components are between “A” component and “B” component. Also, the description of “A” component “adjacent to” “B” component herein may contain the situations that “A” component is directly “adjacent to” “B” component or one or more additional components are between “A” component and “B” component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
       FIG. 1A  is a three-dimensional view of an electronic device according to an embodiment of the invention, and  FIG. 1B  is an exploded view of the electronic device of  FIG. 1A . Referring to  FIG. 1A  and  FIG. 1B , the electronic device  100  of the embodiment is, for example, a notebook computer. The electronic device  100  includes a screen  110 , a base  120 , and a touch keyboard  130 . The screen  110  has a display area  112 , and the display area  112  is capable of displaying a dynamic image frame. The base  120  is connected to the screen  110 , and the touch keyboard  130  is disposed on the base  120 . 
       FIG. 2A  is a three-dimensional view of a carrier board, a light emitting device, a light guide unit, and a reflection unit of  FIG. 1B ,  FIG. 2B  is an enlarged view of a region R of  FIG. 2A ,  FIG. 3  is a cross-sectional view of the carrier board and the light guide unit of  FIG. 1B  along an I-I line, and  FIG. 4  is a front view of a touch module and a keyboard pattern of  FIG. 1B . Referring to  FIG. 1A ,  FIG. 1B ,  FIG. 2A ,  FIG. 2B ,  FIG. 3 , and  FIG. 4 , the touch keyboard  130  includes a keyboard pattern  132  and a touch module  200 . A sensing space S is located in front of the keyboard pattern  132  (shown in  FIG. 3  and  FIG. 4 ). The touch module  200  is disposed at periphery of the keyboard pattern  132 . Moreover, the keyboard pattern  132  includes a plurality of key patterns  133 . In the embodiment, the key patterns  133 , for example, form a keyboard having English letters, numbers, and symbols. However, in other embodiments, the key patterns  133  may also form a numeric keyboard, a keyboard capable of inputting languages of other nations or multi languages, or form other different types or styles of keyboard. The touch module  200  includes at least one light emitting element  210  (in the embodiment, three light emitting elements  210  are taken as an example), at least one light guide unit  220  (in the embodiment, three light guide units  220  are taken as an example), and at least one optical detector  230  (in the embodiment, two optical detectors  230   a  and  230   b  are taken as an example). The light emitting element  210  is disposed beside the keyboard pattern  132  and is capable of emitting a light beam  212 . In the embodiment, the light emitting element  210  is, for example, an infrared light-emitting diode (IR-LED), and the light beam  212  is, for example, an infrared beam. However, in other embodiments, the light emitting element  210  may also be a light emitter or an electromagnetic wave emitter capable of emitting visible light or electromagnetic waves of other wavelengths. The light guide unit  220  is disposed at a side of the keyboard pattern  132 . The light guide unit  220  has a first surface  222 , a second surface  224  opposite to the first surface  222 , and a light incident surface  226  connected to the first surface  222  and the second surface  224 . The light beam  212  from the light emitting element  210  is capable of entering the light guide unit  220  through the light incident surface  226 , and is capable of being transmitted to the sensing space S through the first surface  222 . 
     In the embodiment, the light guide unit  220  further has a third surface  221  (shown in  FIG. 4 ), a fourth surface  223 , and a fifth surface  225  (shown in  FIG. 3 ). The third surface  221  is opposite to the light incident surface  226 , and is connected to the first surface  222  and the second surface  224 . The fourth surface  223  is connected to the third surface  221  and the light incident surface  226 , and is connected to the first surface  222  and the second surface  224 . The fifth surface  225  is opposite to the fourth surface  223 , and the fifth surface  225  is connected to the third surface  221  and the light incident surface  226 , and is connected to the first surface  222  and the second surface  224 . In other words, the light guide unit  220  is, for example, a light guide bar. In the embodiment, the touch module  200  further includes at least one reflection unit  240 , the reflection unit  240  is disposed on at least one of the second surface  224 , the third surface  221 , the fourth surface  223 , and the fifth surface  225 , and a bended reflection unit  240  disposed on the second surface  224 , the fourth surface  223 , and the fifth surface  225  is illustrated in  FIG. 3  as an example. 
     When the light beam  212  from the light emitting element  210  enters the light guide unit  220 , the light beam  212  is capable of being totally reflected by the first surface  222 , the second surface  224 , the fourth surface  223 , and the fifth surface  225 , and is confined within the light guide unit  220 . However, light scattering microstructures  227  disposed on the surface of the light guide unit  220  spoil the total reflection, and scatter the light beam  212  to the first surface  222 , so that the light beam  212  is transmitted to the sensing space S through the first surface  222 . Alternatively, the light scattering microstructures  227  may also scatter the light beam  212  to the reflection unit  240 , and the reflection unit  240  may reflect the light beam  212  to the first surface  222 , so that the light beam  212  is transmitted to the sensing space S through the first surface  222 . In this way, the light beam  212  from the light guide unit  220  may be evenly transmitted to the sensing space S. In the embodiment, the light scattering microstructures  227  are, for example, disposed on the second surface  224 . However, in other embodiments, the light scattering microstructures  227  may also be disposed on at least one of the first surface  222 , the second surface  224 , the third surface  221 , the fourth surface  223 , and the fifth surface  225 . 
     The optical detectors  230  are disposed beside the sensing space S for sensing the light beam  212  from the sensing space S. In the embodiment, the optical detectors  230  are, for example, complementary metal oxide semiconductor sensors (CMOS sensors), charge coupled devices (CCDs) or other suitable optical detectors. When an object  50  (for example, user&#39;s finger or a stylus) enters the sensing space S and approaches the keyboard pattern  132 , the object  50  may reflect a part of the light beam  212  in the sensing space S to the optical detectors  230  (for example, the optical detectors  230   a  and  230   b  in the embodiment). Then, the touch module  200  of the embodiment may determine a position of the object  50  relative to the keyboard pattern  132  according to images detected by the optical sensors  230 , so as to determine the key pattern  133  where the object  50  is located, and accordingly output a signal corresponding to the key pattern  133 . 
     In the embodiment, the touch keyboard  130  includes a carrier board  270 , and the carrier board  270  includes a keyboard area  272  and a notch  274 . The keyboard pattern  132  is disposed on the keyboard area  272 , and the notch  274  is disposed at an edge of the keyboard area  272 , wherein the light emitting element  210  and the light guide unit  220  are disposed in the notch  274 . In the embodiment, the notch  274  is formed between a protrusion  276  and a protrusion  277  protruded out from the carrier board  270 , wherein the light beam  212  emitted from the first surface  222  may penetrate through the protrusion  276  and enter the sensing space S. In the embodiment, a material of the protrusion  276  is, for example, a material pervious to infrared light. 
     In the embodiment, the touch keyboard  130  further includes a top cover  280 . The top cover  280  has an opening  282 , and the top cover  280  covers the notch  274 , the light emitting element  210 , and the light guide unit  220 . The opening  282  exposes the keyboard pattern  132 . Moreover, the carrier board  270  and the top cover  280  are disposed on the base  120 . 
     In the embodiment, the keyboard pattern  132  is, for example, a thin film printed with a pattern. For example, the thin film is disposed on the keyboard area  272  of the carrier board  270 , and is attached to the keyboard area  272 . For example, the thin film is attached to the keyboard area  272  through an in-mold roller (IMR) technique, adhesive mounting or other suitable methods. However, in other embodiments, the keyboard pattern  132  may also be a patterned printed layer, i.e. the keyboard pattern  132  may be directly printed on the keyboard area  272 . Moreover, in the embodiment, the keyboard pattern  132  is disposed at a position outside the display area  112 , i.e. a position outside the dynamic image frame. 
       FIG. 5  is a block diagram of the touch module of  FIG. 1A . Referring to  FIG. 1B ,  FIG. 4  and  FIG. 5 , in the embodiment, the touch keyboard  200  further includes a control unit  250  and a memory unit  260 . The control unit  250  is electrically connected to the optical detectors  230 , wherein the control unit  250  determines the position of the object  50  entering the sensing space S according to the signals transmitted from the optical detectors  230 . In the embodiment, the control unit  250  is, for example, a digital signal processor (DSP). Moreover, in the embodiment, the control unit  250  further includes a sensor interface  251 , an image processing unit  252 , a general purpose input output (GPIO) interface  253 , a universal serial bus (USB) interface  254 , a micro control unit (MCU)  255 , and a memory control unit  256 . The signals from the optical detectors  230  may be transmitted to internal of the control unit  250  through the sensor interface  251  for processing. 
     The memory unit  260  is electrically connected to the control unit  250 . The memory unit  260  stores position information corresponding to the key patterns  133 , and the control unit  250  determines the key pattern  133  touched by the object  50  according to the position information. In detail, after the keyboard pattern  132  disposed on the keyboard area  272  is determined, a position of the keyboard pattern  132  may be calibrated. In other words, a relationship between coordinates of a position touched by the object  50  and the key pattern  133  pressed by the object is determined, so as to form the position information, and such position information is stored in the memory unit  260 . In the embodiment, the memory unit  260  is, for example, a flash memory or other suitable memories. When the touch keyboard  130  is manufactured, as long as the memory unit  260  storing the position information is electrically connected to the control unit  250 , the touch keyboard  130  may be normally used. Moreover, when a user or a manufacturer wants to change a keyboard configuration, another keyboard pattern  132  may be attached to the keyboard area  272 , and the memory unit  260  storing the position information corresponding to such keyboard pattern  132  is used, so as to change the keyboard configuration. Therefore, it is unnecessary to purchase or manufacture a new keyboard. 
     Moreover, in the embodiment, a memory  290  may be electrically connected to the memory control unit  256 . The memory  290  is, for example, a random access memory (RAM), the memory  290  may store information required to be stored during a computation process of the control unit  250 . In addition, in the embodiment, when the control unit  250  determines the key pattern  133  touched by the object  50  according to the position information, the control unit  250  may output a signal corresponding to the key pattern  133  to a processor (for example, a central processing unit (CPU)) of the electronic device  100  through the USB interface  254 . However, in other embodiments, the control unit  250  may also output the signal corresponding to the key pattern  133  to the processor of the electronic device  100  through other interfaces. Moreover, in other embodiments, the MCU  255  may be used to electrically connect the optical detectors  230  for processing the signals from the optical detectors  230  without using a digital signal processor. 
       FIG. 6  is an operation flowchart of the control unit. Referring to  FIG. 4 ,  FIG. 5 , and  FIG. 6 , the control unit  250  first executes a step S 100 , i.e. receives data transmitted from the optical detectors  230   a  and  230   b.  Then, the control unit  250  executes steps S 102  and S 104 , and in the step S 102 , data of the optical detector  230   a  is obtained, and in the step S 104 , data of the optical detector  230   b  is obtained. Then, the control unit  250  executes a step S 106  to perform image processing to the data received from the optical detector  230   a,  and the control unit  250  executes a step S 108  to perform image processing to the data received from the optical detector  230   b.  The image processing includes reducing a background brightness, adjusting a threshold or performing equalization. Next, results of the steps S 106  and S 108  are synthesized to execute a step S 120 , so as to determine whether the object  50  enters the sensing space S. If not, the step S 100  is repeated, and if the object  50  enters the sensing space S, steps S 122  and S 124  are executed. In the step S 122 , a position of the object  50  is obtained through the optical detector  230   a,  and in the step S 124 , the position of the object  50  is obtained through the optical detector  230   b.  Then, the control unit  250  executes a step S 130 , by which results of the steps S 122  and S 124  are synthesized to calculate the coordinates of the object  50 . In the embodiment, since data transmitted by two optical detectors  230   a  and  230   b  are used, two-dimensional coordinates of the object  50  may be calculated. Then, such two-dimensional coordinates are compared to the position information stored in the memory unit  260 , so as to determine the key pattern  133  touched by the object  50 . Then, a step S 140  is executed, by which a signal corresponding to the key pattern  133  touched by the object  50  is output. Then, the step S 100  is repeated to repeatedly detect a position variation of the object  50 . 
     Since the touch keyboard  130  and the electronic device  100  of the embodiment apply the optical detectors  230  to detect a touch operation of the user, a thickness of the touch keyboard  130  is relatively thin, and a weight thereof is relatively light. In detail, since the touch keyboard  130  applies the keyboard pattern  132  (for example, the aforementioned thin film or printed layer) other than physical keys, the thickness of the touch keyboard  130  is relatively thin, and the weight thereof is relatively light. Therefore, a thickness of the electronic device  100  using the touch keyboard  130  is relatively thin, and the weight thereof is relatively light. Moreover, compared to the physical keys having a problem that external liquid is easy to infiltrate to internal of the keyboard from fissures between the physical keys to short-circuit a circuit board therein, the touch keyboard  130  applying the keyboard pattern  132  (for example, the aforementioned thin film or printed layer) does not have such problem, so that a waterproof function is achieved. 
     It should be noticed that although two optical detectors  230   a  and  230   b  are taken as an example in the embodiment, in other embodiments, a number of the optical detectors  230  may be three or more, or only one. Moreover, in the embodiment, although a situation that the two optical detectors  230   a  and  230   b  are respectively disposed at a top left corner and a top right corner of the keyboard pattern  132  is taken as an example, in other embodiments, the optical detectors  230   a  and  230   b  may also be respectively disposed at a bottom left corner and the top right corner of the keyboard pattern  132 , or other positions. In addition, in the embodiment, the light guide units  220  are respectively disposed at a left side, an upside, and a right side of the keyboard pattern  132 , though in other embodiments, the light guide units  220  may be respectively disposed at the left side, a downside, and the right side of the keyboard pattern  132 , or other positions. In the embodiment, the control unit  250  determines a position of the object  50  according to reflected light of the object  50  detected by the optical detectors  230 , i.e. determines the position of the object  50  according to detected bright spots. However, in other embodiments, the control unit  250  may also determine a position of the object  50  according to dark spots detected by the optical detectors  230 , wherein the dark spots are generated due to that the object  50  shields the backlight. 
       FIG. 7  is an exploded view of an electronic device according to another embodiment of the invention,  FIG. 8  is a three-dimensional view of a reversed touch keyboard of  FIG. 7 , and  FIG. 9  is a cross-sectional view of a touch keyboard of  FIG. 7  along an II-II line. Referring to  FIGS. 7-9 , the electronic device  100 ′ of the embodiment is similar to the electronic device  100  of  FIG. 1A , and differences therebetween are as follows. In the electronic device  100 ′ of the embodiment, the carrier board  270  and the top cover  280  of the electronic device  100  are integrated to form a top cover  280 ′ shown in  FIGS. 7-9 . In detail, in the present embodiment, the top cover  280 ′ includes an upper surface  281 ′, a lower surface  283 ′, a recessed area  285 ′, and a notch  287 ′. The lower surface  283 ′ is opposite to the upper surface  281 ′. The recessed area  285 ′ is disposed on the upper surface  281 ′, wherein the keyboard pattern  132  is disposed in the recessed area  285 ′. The notch  287 ′ is disposed on the lower surface  283 ′, and is located around the recessed area  285 ′. The light emitting element  210  and the light guide unit  220  are disposed in the notch  287 ′, the top cover  280 ′ covers the base  120 , and the lower surface  283 ′ faces to the base  120 . In the embodiment, the notch  287 ′ may be formed between a sidewall  284 ′ and a sidewall  286 ′, and the light beam  212  emitted from the first surface  222  may penetrate through the sidewall  284 ′ and enter the sensing space S. 
     In  FIG. 1A , the optical detectors  230  are disposed on the top cover  280 , though in the embodiment, the optical detectors  230  are disposed in internal of a frame  288 ′ of the top cover  280 ′. 
     The electronic device  100 ′ and the touch keyboard  130 ′ of the embodiment also have relatively thin thickness and light weight, and have a waterproof function. 
       FIG. 10  is a three-dimensional view of an electronic device according to still another embodiment of the invention. Referring to  FIG. 10 , the electronic device  100 ″ of the embodiment is similar to the electronic device  100  of  FIG. 1A , and differences therebetween are as follows. In the embodiment, a touch keyboard  130 ″ of the electronic device  100 ″ further includes a projection module  295 ″, and a keyboard pattern  132 ″ is an image projected by the projection module  295 ″, i.e. an image projected by the projection module  295 ″ on the keyboard area  272  of the carrier board  270 . 
     It should be noticed that the aforementioned touch keyboard  130 ,  130 ′ or  130 ″ is not limited to be used in a notebook computer, and since a size thereof is not limited, the touch keyboard may also be applied to mobile phones, personal digital assistants (PDAs), digital cameras or other electronic devices. Moreover, the aforementioned touch keyboard  130 ,  130 ′ or  130 ″ may also be an independent external keyboard. Namely, after the base  120  of the electronic device is changed to a base of the touch keyboard  130 ,  130 ′ or  130 ″, the touch keyboard  130 ,  130 ′ or  130 ″ may be an independent keyboard, the independent keyboard may be connected to a computer host or other electronic devices through a cable, or may be connected to the computer host or the other electronic devices through a wireless transmission module. 
     In summary, the embodiments of the invention may achieve at least one of the following effects. The touch keyboard and the electronic device according to the embodiments of the invention use the optical detector to detect a touch operation of the user, so that a thickness of the touch keyboard is relatively thin, and a weight thereof is relatively light. Accordingly, the electronic device according to the embodiments of the invention may have a small size and a light weight. 
     The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the term “the invention”, “the present invention” or the like does not necessarily limit the claim scope to a specific embodiment, and the reference to particularly preferred exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. Moreover, these claims may refer to use “first”, “second”, etc. following with noun or element. Such terms should be understood as a nomenclature and should not be construed as giving the limitation on the number of the elements modified by such nomenclature unless specific number has been given. The abstract of the disclosure is provided to comply with the rules requiring an abstract, which will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims. Moreover, no element and component in the present disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.