BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an electronic apparatus, in particular, to a keyboard module applied in an electronic apparatus. 2. Description of Related Art Along with the development of technologies, people rely more and more on electronic products. Various handheld electronic apparatuses, such as ultra mobile personal computer (UMPC), personal digital assistant (PDA), and mobile phone, have been developed to meet people's requirement for high-speed, high-performance, light, and slim electronic products. The keys on an existing keyboard (either a keyboard of a desktop computer or a keyboard of a notebook computer) usually require a large stroke. Accordingly, such a keyboard cannot be applied to a handheld electronic apparatus due to the limitation in the thickness of the handheld electronic apparatus. To be specific, the key structure in an existing keyboard applied in a handheld electronic apparatus includes a circuit board, a rubber layer, and a key, wherein the circuit board has at least one metal dome switch, and the rubber layer has a protrusion corresponding to the metal dome switch. A user can sense the tactile feedback provided by the metal dome switch when the user presses the key. However, a keyboard adopting such a key structure is usually very thick.
Document DE 20 2006 011 302 U1 discloses a keyboard having a membrane circuit sheet disposed on the carrying surface of a supporting structure, a decorative sheet, and a vibrator. When the vibrator is actuated, vibration energy is not transmitted directly to the user interface. Thus, a high level of energy is required to generate a desired vibration amplitude. SUMMARY OF THE INVENTION Accordingly, the present application is directed to a keyboard module suitable for being applied to an electronic apparatus and overcoming the disadvantages mentionned above. The present application is directed to an electronic apparatus having a keyboard module according to claim 1 or 2. The present application provides an electronic apparatus including a display unit and the keyboard module as described above. The keyboard module is electrically connected to the display unit. As described above, when a user presses the membrane circuit sheet directly or indirectly, the vibrator vibrates the supporting structure and the membrane circuit sheet disposed thereon to provide a tactile feedback in correspondence with the press of the user to the membrane circuit sheet. In addition, the thickness of the keyboard module which adopts foregoing membrane circuit sheet is reduced. 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. 1 is a perspective view of an electronic apparatus according to an example. FIG. 2A is a cross-sectional view of a keyboard module in FIG. 1. FIG 2B illustrates a decorative surface of a decorative sheet in FIG. 2A. FIG. 2C illustrates that the keyboard module in FIG. 2A is pressed by a finger. FIG. 3 is a cross-sectional view of a keyboard module according to an example. FIG. 4 is a cross-sectional view of a keyboard module according to an example. FIG. 5 is a cross-sectional view of a keyboard module according to an example. FIG. 6A is a cross-sectional view of a keyboard module according to an example. FIG. 6B is a cross-sectional view of a keyboard module according to an example. FIG. 7 is a cross-sectional view of a keyboard module according to an example. FIG. 8A is a cross-sectional view of a keyboard module according to an example. FIG. 8B is a cross-sectional view of a keyboard module according to an example. FIG. 8C is a cross-sectional view of a keyboard module according to an example. FIG. 9A is a cross-sectional view of a keyboard module according to an embodiment of the present invention. FIG. 9B is a partial enlarged top view of the first elastic layer in FIG. 9A. FIG. 10 is a cross-sectional view of a keyboard module according to an embodiment of the present invention. FIG. 11A is a cross-sectional view of a keyboard module according to an example. FIG. 11B is a cross-sectional view of a keyboard module according to an embodiment of the present invention. DESCRIPTION OF THE EMBODIMENTS Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. FIG. 1 is a perspective view of an electronic apparatus. Referring to FIG. 1, the electronic apparatus 10 may be an ultra mobile personal computer (UMPC). The electronic apparatus 10 includes a display unit 12 and a keyboard module 100, wherein the keyboard module 100 is electrically connected to the display unit 12. In the present embodiment, the keyboard module 100 and the display unit 12 are independent to each other. However, the keyboard module 100 and the display unit 12 may also be disposed on the same body. FIG. 2A is a cross-sectional view of the keyboard module in FIG. 1. Referring to FIG. 2A, the keyboard module 100 includes a supporting structure 110, a membrane circuit sheet 120, and a vibrator 130. The supporting structure 110 has a carrying surface 112. The membrane circuit sheet 120 is disposed on the carrying surface 112 of the supporting structure 110 and has a plurality of triggers 122. The vibrator 130 is connected to the supporting structure 110 and disposed below the supporting structure 110. When these triggers 122 are pressed by a user directly or indirectly, the vibrator 130 starts to vibrate to provide a tactile feedback in correspondence with the press of the user to the triggers 122. To be specific, the triggers 122 usually include an upper electrical contact and a lower electrical contact (not shown), and when these triggers 122 are pressed by the user directly or indirectly and accordingly the two electrical contacts touch each other, signals are generated by these triggers 122 and transmitted to a central processing unit (CPU) or a microprocessor unit (MPU) in the electronic apparatus 10 (referring to FIG. 1) or a MPU in the keyboard module 100 (not shown). The CPU or MPU then drive the vibrator 130 to vibrate correspondingly so as to provide a tactile feedback in correspondence with the press of the user to the triggers 122. In the present embodiment, the vibrator 130 may vibrate vertically. However, the vibrator 130 may also vibrate horizontally or in other directions. In addition, the vibrator 130 may be a revolving vibrator or a linear vibrator. FIG. 2B illustrates the decorative surface of a decorative sheet in FIG. 2A. Referring to FIG 2A and FIG. 2B, the keyboard module 100 may further include a decorative sheet 140, wherein the decorative sheet 140 is disposed on the membrane circuit sheet 120 and has a decorative surface 142. In the present example, the decorative sheet 140 has a plurality of marks (for example, icons, symbols, characters, or numbers). Besides, the decorative sheet 140 may further have a plurality of protrusions 144, wherein the protrusions 144 are protruded from the decorative surface 142 and are respectively corresponding to the triggers 122. The marks are respectively located on the protrusions 144 so that when a user touches these protrusions 144 with a finger, the position of the finger can be obtained. Referring to FIG. 2A, the keyboard module 100 may further include a first elastic layer 150 disposed between the decorative sheet 140 and the membrane circuit sheet 120. The first elastic layer 150 has a plurality of protrusions 152 and a plurality of spacers 154, wherein the protrusions 152 are respectively corresponding to the triggers 122, and one of the spacers 154 is disposed between adjacent two of the protrusions 152. In the present example, the first elastic layer 150 may be made of rubber. Besides, the thicknesses of the protrusions 152 and the spacers 154 are greater than the thicknesses of other portions of the first elastic layer 150. FIG. 2C illustrates that the keyboard module in FIG 2A is pressed by a finger. Referring to FIG 2C, when a user presses a protrusion 144 on the decorative sheet 140 with a finger, the protrusion 152 is moved downward to press the membrane circuit sheet 120 so that the trigger 122 corresponding to the protrusion 144 is also pressed. Accordingly, the vibrator 130 connected to the supporting structure 110 starts to vibrate to provide a tactile feedback in correspondence with the press of the user to the trigger 122. It should be noted that when the protrusion 152 is pressed by an external force and accordingly presses the membrane circuit sheet 120, the spacer 154 adjacent to the protrusion 152 reduces the deformations of other areas or the first elastic layer 150, so that inappropriate press to the trigger 122 corresponding to another protrusion 152 and accordingly the generation of unneeded signal can be avoided. FIG. 3 is a cross-sectional view of a keyboard module. Referring to both FIG. 2A and FIG. 3, the keyboard module 100A in FIG. 3 is similar to the keyboard module 100 in FIG. 2A, and the differences between the two are that the decorative sheet 140A and the first elastic layer 150A of the keyboard module 100A in FIG. 3 are formed integrally, and a plurality of vibrators 130A are connected to the supporting structure 110A and are located at one side of the membrane circuit sheet 120. FIG. 4 is a cross-sectional view of a keyboard module. Referring to FIG. 2A and FIG. 4, the keyboard module 100B in FIG. 4 is similar to the keyboard module 100 in FIG 2A, and the difference between the two is that the keyboard module 100B in FIG. 4 further includes a light source 160. The light source 160 is disposed at one side of the first elastic layer 150B and emits a light beam into the first elastic layer 150B, wherein the first elastic layer 150B is transparent and has a reflective surface 156 close to the first elastic layer 150B for reflecting the light beam to the decorative sheet 140B, so as to display the marks on the decorative surface 142B. In the present example the first elastic layer 150B may be made of transparent silicone, and the decorative surface 142B of the decorative sheet 140B is a plane. FIG. 5 is a cross-sectional view of a keyboard module. Referring to both FIG. 2A and FIG. 5, the keyboard module 100C in FIG. 5 is similar to the keyboard module 100 in FIG. 2A, and the difference between the two is that the keyboard module 100C in FIG. 5 further includes a light source 160 and a light guiding layer 170. The light guiding layer 170 is disposed between the decorative sheet 140B and the first elastic layer 150. The light source 160 is disposed at one side of the light guiding layer 170 for emitting a light beam to the light guiding layer 170, wherein the light guiding layer 170 guides the light beam to the decorative sheet 140B to display the marks (referring to FIG. 2B) on the decorative surface 142B above the decorative sheet 140B. Besides, the decorative surface 142B of the decorative sheet 140B is a plane. FIG 6A is a cross-sectional view of a keyboard module. Referring to both FIG. 2A and FIG. 6A, the keyboard module 100D in FIG 6A is similar to the keyboard module 100 in FIG. 2A, and the difference between the two is that the keyboard module 100D in FIG. 6A further includes a light emitting layer 180 disposed between the decorative sheet 140B and the first elastic layer 150. Besides, the decorative surface 142B of the decorative sheet 140B is a plane. The light emitting layer 180 emits a light beam to the decorative sheet 140B so as to display the marks (referring to FIG. 2B) on the decorative surface 142B above the decorative sheet 140B. In the present example, the light emitting layer 180 may be an electro-luminescence (EL) film or an organic electro-luminescence (OEL) film. FIG. 6B is a cross-sectional view of a keyboard module. Referring to both FIG. 6A and FIG. 6B, the keyboard module 100E in FIG. 6B is similar.to the keyboard module 100D in FIG. 6A, and the difference between the two is that the protrusions 152B of the first elastic layer 150B of the keyboard module 100E in FIG. 6B further pass through the light emitting layer 180A and are extended to the decorative sheet 140B. FIG. 7 is a cross-sectional view of a keyboard module. Referring to FIG. 2A and FIG. 7, the keyboard module 100F in FIG. 7 is similar to the keyboard module 100 in FIG. 2A, and the difference between the two is that the keyboard module 100F in FIG. 7 further includes a touch sensing panel 190 disposed between the decorative sheet 140B and the first elastic layer 150. In the present example, the touch sensing panel 190 may be a capacitive touch panel or a resistive touch panel such that a user can input signals with a finger. FIG. 8A is a cross-sectional view of a keyboard module. Referring to FIG. 7 and FIG. 8A, the keyboard module 100G in FIG. 8A is similar to the keyboard module 100F in FIG. 7, and the difference between the two is that the keyboard module 100G in FIG. 8A further includes a light emitting layer 180 disposed between the touch sensing panel 190 and the first elastic layer 150. FIG. 8B is a cross-sectional view of a keyboard module. Referring to FIG. 8A and FIG. 8B, the keyboard module 100H in FIG. 8B is similar to the keyboard module 100G in FIG. 8A, and the difference between the two is that the protrusions 152B of the first elastic layer 150B of the keyboard module 100H in FIG. 8B further pass through the light emitting layer 180A and are extended to the touch sensing panel 190. FIG. 8C is a cross-sectional view of a keyboard module. Referring to FIG. 8B and FIG. 8C, the keyboard module 100I in FIG. 8C is similar to the keyboard module 100H in FIG. 8B, and the difference between the two is that the protrusions 152C of the keyboard module 100I in FIG 8C further pass through the light emitting layer 180A and the touch sensing panel 190A and are extended to the decorative sheet 140B. FIG. 9A is a cross-sectional view of a keyboard module according to an embodiment of the present invention, and FIG. 9B is a partial enlarged top view of the elastic layer in FIG. 9A. Referring to FIG 3, FIG. 9A, and FIG. 9B, the keyboard module 100J in FIG. 9A is similar to the keyboard module 100A in FIG. 3, and the difference between the two is that the first elastic layer 150D of the keyboard module 100J in FIG. 9A further has a plurality of vibration conductors 158, and these vibration conductors 158 pass through the membrane circuit sheet 120A and are extended to the supporting structure 110A. Because both the first elastic layer 150D and the membrane circuit sheet 120A can absorb part of the vibration power of the vibrator 130A, in the keyboard module 100J of the present embodiment, the vibration conductors 158 are in contact with the supporting structure 110A so that the power consumption can be reduced and a user can sense the vibration obviously. To be specific, in the present embodiment, each of the vibration conductors 158 is disposed between any adjacent four protrusions 152 for conducting the vibration. In other words, when a user press a protrusion 144 on the decorative sheet 140C with a finger, the protrusion 152 moves downward to press the membrane circuit sheet 120A so that a trigger 122 corresponding to the protrusion 144 is pressed. Then, the vibrator 130A connected to the supporting structure 110A receives a corresponding electronic signal and starts to vibrate, and the vibration conductors 158 around the protrusions 152 conduct the vibration of the vibrator 130A to the decorative sheet 140C to provide a tactile feedback in correspondence with the press of the user to the trigger 122. Thus, most of the vibration power issued by the vibrator 130A is conducted to the decorative sheet 140C through the vibration conductors 158 and accordingly the vibration amplitude is increased. FIG. 10 is a cross-sectional view of a keyboard module according to an embodiment of the present invention. Referring to FIG. 10 and FIG. 9A, the keyboard module 100K in FIG. 10 is similar to the keyboard module 100J in FIG 9A, and the differences between the two are that the keyboard module 100K in FIG. 10 further includes a plurality of auxiliary vibration conductors 132, and the supporting structure 110B has an upper supporting structure 114 and a lower supporting structure 116. The auxiliary vibration conductors 132 span between a portion of the lower supporting structure 116 in contact with the vibrator 130A and another portion of the lower supporting structure 116 not in contact with the vibrator 130A. To be specific, the upper supporting structure 114 is disposed between the decorative sheet 140C and a plurality of vibrators 130A, and the lower supporting structure 116 is disposed between a plurality of vibrators 130A and a plurality of auxiliary vibration conductors 132, wherein the auxiliary vibration conductors 132 are used for conducting the vibration of the vibrators 130A to the center of the lower supporting structure 116 or a part of the lower supporting structure 116 which receives less vibration, so that the decorative sheet 140C can provide approximately the same tactile feedback to the user at any position thereon. Besides, the auxiliary vibration conductors 132 and the lower supporting structure 116 may also be integrated into a single component. FIG. 11A is a cross-sectional view of a keyboard module. Referring to FIG. 3 and FIG. 11A, the keyboard module 100L in FIG. 11A is similar to the keyboard module 100A in FIG. 3, and the difference between the two is that the second elastic layer 150E of the keyboard module 100L in FIG. 11A is disposed between the membrane circuit sheet 120 and the supporting structure 110A. In short, the relative position between the second elastic layer 150E and the membrane circuit sheet 120 in FIG. 11A is contrary to the relative position between the first elastic layer 150A and the membrane circuit sheet 120 in FIG. 3. FIG. 11B is a cross-sectional view of a keyboard module according to an embodiment of the present invention. Referring to FIG. 11A and FIG. 11B, the keyboard module 100M in FIG 11B is similar to the keyboard module 100L in FIG. 11A, and the difference between the two is that the second elastic layer 150F of the keyboard module 100M in FIG. 11B further has a plurality of vibration conductors 158, wherein the vibration conductors 158 are extended to the decorative sheet 140C. In overview, the keyboard module has a vibrator such that when a user presses the membrane circuit sheet directly or indirectly, the vibrator vibrates the supporting structure and the membrane circuit sheet thereon so as to provide a tactile feedback in correspondence with the press of the user to the membrane circuit sheet. Thereby, the tactile feedback in a conventional keyboard is simulated by using the vibrator, so as to indicate that the membrane circuit sheet has been pressed. Moreover, the thickness of such a keyboard module which adopts the membrane circuit sheet can be reduced. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. |
