WO2005078948A1

WO2005078948A1 - Button plate and personal portable device using a plastic sheet

Info

Publication number: WO2005078948A1
Application number: PCT/KR2005/000384
Authority: WO
Inventors: Chul Park
Original assignee: Gnc Co., Ltd.
Priority date: 2004-02-12
Filing date: 2005-02-11
Publication date: 2005-08-25

Abstract

There are provided a button plate which has a small thickness and can be simply assembled and a personal portable device employing the button plate. The personal portable device includes a main body including a key pad hole, a button plate installed at the main body in which the key pad hole is formed, and a keystroke sensor part including push sensors. The button plate includes the button pattern arranged in response to a button area, a high hardness button sheet formed of a high hardness material, and a plastic sheet formed on one side of the high hardness button sheet and connecting the button pattern to each other. Since the button plate is manufactured using a thin plastic sheet and a high hardness button sheet, the button plate is kept in a slim configuration and has a soft touch while pushing a key because of a button pattern of the high hardness button sheet solves the problem of hardness.

Description

BUTTONPLATE AND PERSONAL PORTABLEDEVICE USINGAPLASTIC SHEET

Technical Field The present relates to a keystroke part, and more particularly, to a button plate and a personal portable device which are advantageous to easy manufacturing and assembly and the thickness of which can be reduced.

Background Art Buttons of a keystroke part are pushed in order to input numbers in personal portable devices such as mobile phones. In accordance with improvement of a technology related to mobile phones, the buttons of the keystroke part are utilized not only for inputting phone numbers, but also for inputting letters to transmit messages or all sorts of functions such as games. This tendency is applied not only mobile phones but also other devices and general personal portable devices. FIG. 1 is an exploded perspective view illustrating a keystroke part of a conventional mobile phone 1. Referring to FIG. 1 , the keystroke part of the conventional mobile phone 1 includes a key pad 10 on which buttons 12 are formed, an adhesive sheet 20 on which dome switches 22 are formed, and a printed circuit board (PCB) 30 on which electrodes 32 in a circular shape are formed. The key pad 10 is formed of rubber, silicone, or synthetic resin, and the buttons 12 are formed on the top surface of the key pad 10 to be formed a single body with the key pad by injection molding. The buttons project from the top surface of the key pad, and the projected buttons may be exposed via holes 4 formed in a top case 2, respectively. The adhesive sheet 20 including the dome switches 22 is provided below the key pad 10. The dome switches 22 are formed of metal. When a dome switch 22 is flatly pushed, it touches the electrodes 32 to electrically connect the nearby electrodes 32, and when not pushed, it is separated from the electrodes 32 to return to an original state. The dome switches 22 may be formed on the adhesive sheet 30. However, since the dome switches 22 are generally formed of a material different from the adhesive sheet 30, the dome switches 22 are adhered to the adhesive sheet 30 using an adhesive agent. The PCB 30 includes the electrodes 32, and the electrodes are disposed below the buttons 12 and the dome switches 22 corresponding to the locations of the buttons 12 and the dome switches 22. The electrodes 32 have a shape of a concentric circle and are electrically connected via the dome switches 22. As described above, the key pad 10 is disposed below the top case 2, and the buttons are disposed to be exposed or projected via the holes of the top case 2. In order to form the keystroke part, the top case 2 overlaps with the key pad 10 such as to make the keystroke part thick. Also, the holes 4 should be formed in the top case 2, and the buttons should be disposed corresponding to the respective holes 4. Accordingly, a fabricating process is complicated, and faulty products can be frequently produced. FIG. 2 is a cross-sectional view of a conventional keystroke part. Referring to FIG. 2, buttons 12 of a mobile phone are formed on a key pad 10, and interval supports 16 and push-protrusions 14 are formed below the key pad 10 facing below. Therefore, when a user pushes the button 12, the push-protrusion 14 pushes the dome switch 22 and the dome switch 22 is transformed such as to connect the nearby electrodes 32 disposed below. According to connecting the electrode 32, it is ascertained whether the button 12 is pushed, and a signal generated by the electrode 32 may be transferred to an inner circuit in order to input numbers or letters. Since the size of the button is much larger than the size of the push-protrusion 14, a force of pushing the button 12 is gathered to be transferred to the push-protrusion 14 and the dome switch 22 can be easily pushed using a small force.

Disclosure of Invention The present invention provides a button plate and a personal portable device employing the same, in which a thickness of a keystroke part is minimized and the hardness is improved though a keystroke part is thin. The present invention also provides a button plate and a personal portable device in which not only a thickness of a keystroke part but also a personal portable device can be reduced. The present invention also provides a button plate and a personal portable device which can be simply manufactured and assembled. The present invention also provides a button plate and a personal portable device which can be simply represented in various designs and colors, thereby providing products of excellent quality. According to an aspect of the present invention, there is provided a personal portable device including a main body including a key pad hole, a button plate installed in the key pad hole and providing a plurality of buttons, and a keystroke part for sensing a button input in the button plate. The button plate includes a high hardness button sheet and a plastic sheet such as to be formed to a small thickness. Though the button plate has the small thickness using the plastic sheet, the high hardness button sheet includes a button pattern arranged in response to a button area and characterized by relatively high hardness, thereby solving the problem of hardness of a plastic sheet. Since a conventional keystroke part includes a key pad of rubber material, buttons formed projected from the key pad, and a case of a mobile phone covers the key pad, thereby preventing the mobile phone from being slimmed down. However, since the button plate of the present invention is formed of a single wall and hardness of the plastic sheet is reinforced with a high hardness material such as metal, the button plate can be manufactured to have a smaller thickness than a thickness of a wall of a case. Also, since the button plate in a single body can form a wall of a case and be used for keystroking, it is possible to decrease the number of components and notably reduce the thickness of a terminal. Also, since various designs can be expressed on the plastic sheet, it is simple to manufacture. In addition, since buttons are projected and designed at a time, manufacture cost can be reduced. Personal portable devices of the specification are portable electric electronic devices such as personal digital assistants (PDAs), smart phones, handheld PCs, mobile phones, or MP3 players. The personal portable device can include a predetermined communication module such as a code division multiplexing access (CDMA) module, a bluetooth module, or an infrared data association (IrDA) module and be equipped with a predetermined microprocessor reproducing multimedia information, thereby being used as a common designation concept of terminals having predetermined operation ability. Also, various keystroke sensor parts can be employed depending on the level of applied technology and to fit a terminal, in addition to the keystroke sensor part composed of dome switches and electrodes.

Brief Description of Drawings FIG. 1 is an exploded perspective view illustrating a keystroke part of a conventional mobile phone; FIG. 2 is a cross-sectional view of a conventional keystroke part; FIG. 3 is an exploded perspective view illustrating a personal portable device and a button plate according one embodiment of the present invention; FIG. 4 is a partial enlarged view illustrating the union between the personal portable device and the button plate; FIG. 5 is a bottom view of the button plate; FIG. 6 is a cross-sectional view of the button plate of FIG. 5; FIGS. 7 through 12 are partial enlarged views of a button sheet according to embodiments of the present invention; FIG. 13 is a cross-sectional view of a button plate according to one embodiment of the present invention; FIGS. 14 through 18 are diagrams illustrating a method of forming a metal pattern on a plastic sheet; FIG. 19 is a cross-sectional view of a button plate according to one embodiment of the present invention; FIG. 20 is a cross-sectional view of a button plate according to one embodiment of the present invention; FIG. 21 is a cross-sectional view of a button plate according to one embodiment of the present invention; FIG. 22 is a cross-sectional view of a button plate according to one embodiment of the present invention; FIG. 23 is a bottom view of a button plate according to one embodiment of the present invention; FIG. 24 is a sided- view illustrating the button plate of FIG. 23 and a keystroke sensor part; FIG. 25 is a sided- view of a button plate according to one embodiment of the present invention; FIG. 26 is a cross-sectional view of a button plate according to one embodiment of the present invention; FIG. 27 is a top view of the button plate of FIG. 26; FIG. 28 is a cross-sectional view of a button plate according to one embodiment of the present invention; FIGS. 29 and 30 are cross-sectional views of button plates according to embodiments of the present invention; and FIG. 31 is an exploded perspective view of a button plate according to one embodiment of the present invention.

Best Mode for Carrying Out the Invention Hereinafter, the present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention should not be construed as being limited to the embodiments set forth herein. FIG. 3 is an exploded perspective view illustrating a personal portable device 200 and a button plate 100 according an embodiment of the present invention, and FIG. 4 is a partial enlarged view illustrating the union between the personal portable device 200 and the button plate 100. Referring to FIGS. 3 and 4, the personal portable device 200 includes a main body 210, the button plate 100, and a keystroke sensor part 230. The main body 210 may include a case, inner and outer components, and a circuit configuration, which include general function of a terminal. For example, in case of a mobile phone, the main body 210 may include a terminal case, a keystroke part, a display module, a wireless transceiver module, a battery, a microphone, an a receiver. Also, although the main body of FIG. 3 is in a bar shape, a main body according to another embodiment of the present invention can be formed in diverse types such as a flip, a folder, a slide, and a swing. The main body 210 includes a front case 212 and a rear case 214. The front upper portion of the front case 212 is equipped with a liquid crystal display (LCD) portion, and a key pad hole 216 for being equipped with a keystroke part is provided in the front lower portion of the front case 212. The button plate 100 is installed at the inner surface of the front case 212, and the keystroke sensor part 230 is provided at the rear side of the button plate 100. The button plate 100 is formed in a similar shape of the key pad hole 216 and installed in the key pad hole 216, thereby providing the keystroke part forming a single wall to barrier the key pad hole 216. As after-mentioned, the button plate 100 includes a button sheet 110 including metal patterns 112 and a plastic sheet 120 formed on the button sheet 110. Since the button sheet 100 and the plastic sheet 120 are very thin, the button plate 100 may be formed to a thickness of approximately 0.05 to 0.5mm. Since a thin plate of the metal pattern 112 is included, the strength to keep the configuration of the button plate 100 and the sensitivity of buttons can be maintained. The button plate 100 is installed in the key pad hole 216, thereby installing the keystroke part at a time. Accordingly, the keystroke part can be kept thin, assembling is easy, and the cost of manufacturing can be notably reduced. Also, guide holes 124 are formed around the button plate 100, and guide projections 217 are formed in the key pad hole 216 in response to the guide holes 124. The button plate 100 may be screwed to the front case 212, the guide projections 217 and the guide holes 124 can be used in order to locate the button plate 100 in the key pad hole 216 at first. Namely, the guide holes 124 is situated on the guide projection 217 to join with each other, thereby preventing relative moves between the front case 212 and the button plate 100. The keystroke sensor part 230 includes push sensors composed of a dome switch 232 and a contact point electrode 234. The metal pattern 112 are provided in response to respective buttons of the button plate 100, and the dome switches 232 and the contact point electrodes 234 of the keystroke sensor part 230 are provided behind the metal pattern 112. Accordingly, when a user pushes the buttons of the button plate 110, a pushing force is transmitted to the dome switch 232 via the metal pattern 112 and the dome switch 232 is temporarily transformed to electrically connect the contact point electrode 234. An input signal is generated in response to connecting the contact point electrode 234. An input signal corresponding to each of the buttons is particular such as to be used for inputting numbers or letters. FIG. 5 is a bottom view of the button plate 100. Referring to FIG. 5, the button plate 100 includes the button sheet 110 including a high solidity button pattern and the plastic sheet 120 formed on the button sheet 110. The button sheet 110 is formed of a metal in a single body, and the button pattern 112 is independently moved. The button pattern 112 formed of a material having a higher solidity than the plastic sheet 120, such as ceramic or other synthetic resins having a higher solidity than the plastic sheet 120 in addition to metal. In an embodiment of the present invention, the high solidity button pattern is formed of a metal, and the button sheet 110 includes the metal pattern 112. The metal pattern 112 is arranged in a button area in which buttons are disposed of the keystroke part. The metal pattern 112 can be formed in various shapes according to the shape of button, such as a square, an oval, or a circle. Also, a plurality of the metal pattern 112 can be formed separately or connected to the other adjacent metal pattern 112 to form a single button sheet 110. The metal pattern 112 can be formed of copper, a copper alloy, stainless steel, aluminum, titanium, platinum, or nickel. The metal pattern 112 is formed to a thickness of approximately 0.05 to 1mm. Since the metal pattern 112 has a higher solidity than plastic, a solid form is easily maintained and not easily bent even if the metal pattern 112 is very thin. Accordingly, comparing to conventional configurations of a keystroke part, not only the thickness of button plates but also the thickness of personal portable devices can be reduced. The plastic sheet 120 is formed on the button sheet 110. The plastic sheet 120 is formed of polypropylene (PP), oriented polypropylene (OPP), polyethyleneterephthalate (PET), ethylenevinylacetate (ENA), polyethylene (PE), polyvinyl chloride (PNC), Acrylonitrile Butadiene Styrene (ABS), polycarbonate (PC), and urethane. The plastic sheet 120 is formed to a thickness of approximately lO m to 1mm and is formed by adhering or laminating. Since the plastic sheet 120 is adhered to the metal pattern 112 to relatively connect each other, the metal pattern 112 can be elastically supported. Accordingly, after a user pushes a part of the button area, the metal pattern 112 and the plastic sheet 120 are return to original locations caused by the stability of the dome switch 232 and the plastic sheet 120. Push protrusions 132 are formed below the each of the metal pattern 112. Interval supports 134 are formed around the metal pattern 112. The interval supports 134 defining an interval between the plastic sheet 120 and a substrate on which electrodes are formed may be formed in various methods. For an example, the location of the push-protrusions 132 is printed using silicone ink as a material having elasticity at the bottom surface of the plastic sheet 120 and the metal pattern 112. The printed silicone ink is hardened by heat in order to maintain a form in which the push protrusions 132 are projected. For another example, liquid silicone as material having elasticity is extruded on the location of the push protrusions 132 at the bottom surface of the plastic sheet 120 and the metal pattern 112. The extruded liquid silicone is hardened by heat in order to maintain a form in which the push protrusions 132 are projected. When materials which can be hardened by ultraviolet rays or heat in addition to silicone ink and liquid silicone is applied to the locations of the push-protrusions 132, a projected form of the push protrusion 132 can be maintained. The shape of button sheets and button pattern in addition to the button sheet 110 can be variously controlled. FIGS. 7 through 12 are partial enlarged views of a button sheet according to embodiments of the present invention. Referring to FIG. 7, a button pattern 112a is formed in a single body on a button sheet 110a. Each of the button patterns 112a is defined by separating slits 116a formed at the both sides of the respective button patterns 112a. Accordingly, the button patterns 112a are formed in a bridge shape by the separating slit 116a. Since the button patterns 112a are formed of a metal, the button pattern 112a can be partially transformed within predetermined limits when a user pushes a button. In this case, a distance in which the button pattern 112a is moved can be changed to reach and operate a push sensor such as a dome switch. Referring to FIG. 8, button patterns 112b are formed in a single body on a button sheet 110b. The button patterns 112b are defined by separating slits 116b formed at the both sides of the button pattern 112b. The button pattern 112b is formed in a bridge shape by the separating slits 116b. The button pattern 112b adjacent to each other shares the separating slit 116b disposed between the button patterns 112b, which is different from the button sheet 110a of FIG. 7. Of course, since the button pattern 112b is formed of a metal, the button pattern can be transformed within predetermined limits when a user pushes a button. The button pattern 112b functions the same as the button pattern 112a of FIG. 7, Though the separating slits 116a and 116b are formed at the both sides of the button pattern 112a and 112b in FIGS. 7 and 8, separating slits can be formed at the both sides or top and bottom of a button pattern and also button pattern can be designed in various shapes depending on the purpose of designers. Referring to FIG. 9, four separating slits 116c are formed in response to the four edges of a button pattern 112c, and the button pattern 112c is formed in a shape of approximately square. Aspects corresponding to four apices of the button pattern 112c and a button sheet 110c are formed in a single body, and aspects corresponding to the four edges are separated from the button sheet 110c. Since the button pattern 112c is formed of a metal, the button pattern 112c can be transformed within predetermined limits when a user pushes a button. In this case, a distance in which the button pattern 112a is moved can be transferred to a sufficient distance to operate a push sensor such as a dome switch. Referring to FIG. 10, three separating slits 116d are formed in response to three edges of a button pattern 112d, and the button pattern 112d is formed in a shape of approximately square. Since the separating slits 116d interposed between the button patterns 112d are alternately formed, the separating slits can be balanced. Portions corresponding to two apices and an aspect of the button pattern 112a and a button sheet 1 lOd are formed in a single body. Since the button pattern 112d is formed of a metal, the button pattern 112d can be transformed within predetermined limits when a user pushes a button. In this case, a distance in which the button pattern 112a is moved can be transferred to a sufficient distance to operate a push sensor such as a dome switch. Referring to FIG. 11, a button pattern 112e is formed in a single body on a button sheet 1 lOe, and separating slits 116e are formed around the button pattern 112e. The button pattern 112e is defined by the separating slits 116e and formed side by side sharing the separating slits 116e as in a shape of teeth. Accordingly, the button pattern 112e is connected to the separating slits 116e in a cantilever shape. One side of the button pattern 112e and the button sheet HOe are connected to form a single body, and the other sides of the button pattern 112e are separated from the button sheet HOe. Since the button pattern 112e is formed of a metal, the button pattern 112e can be transformed within predetermined limits when a user pushes a button. Referring to FIG. 12, a button pattern 112f is formed in a single body on a button sheet 11 Of. Separating slits 116f are formed around the button pattern 112f The separating slits 116f are formed in a zigzag shape around the button pattern 112f, and the button pattern 112f can be connected to the button sheet 11 Of in different directions. In this case, the button pattern 112f is connected to the separating slits 116f in a cantilever shape. When the button pattern 112f looks toward directions different from each other, it can be minimized that a movement is transferred from a part of a button pattern to another adjacent part of a button pattern when a part of a button pattern is moved. FIG. 13 is a cross-sectional view of a button plate according to another embodiment of the present invention. Referring to FIG. 13, a rubber pad 130a including push protrusions 132a and interval supports 134a is provided below a plastic sheet 120 and a metal pattern 112. The rubber pad 130a may be formed of silicone rubber, urethane rubber, or synthetic resins having elasticity and extruded at the bottom of the plastic sheet 120 and fixed by printing, adhering, or thermally pressing. Otherwise, a rubber pad is just disposed at the plastic sheet 120 and maintains a state of being separated from the plastic sheet 120 and simply contacts the plastic sheet 120. The metal pattern 112 formed in a shape and size of a button is adhered to the bottom of the plastic sheet 120 in response to a button area. The metal pattern 112 can be separated from push sensors such as dome switches at a predetermined interval by the push protrusions 132a and the interval supports 134a. There are many methods to adhere a metal pattern to a plastic sheet. As simple methods, one is to adhere a metal pattern to a plastic sheet using a press corresponding to a metal pattern, and another is to previously adhere a thin metal panel to a plastic sheet and etch the thin metal panel to form a metal pattern. Hereinafter, a method of adhering a metal pattern to a plastic sheet using etching will now be described. FIGS. 14 through 18 are diagrams illustrating a method of forming a metal pattern on a plastic sheet. Referring to FIG. 14, a plastic sheet 120 and a thin metal panel 110a are provided. The plastic sheet 120 is separated f om the thin metal panel 110a. However, the plastic sheet 120 can be adhered to the thin metal panel 110a using adhesives and thermally adhered to the thin metal panel 110a using laminating. A plastic sheet can be adhered to a thin metal panel using general adhesives. A plastic sheet of a laminate film and a thin metal panel which are contact each other pass beneath a roller, thereby adhering the plastic sheet to the thin metal panel. A plastic sheet of a laminate film can be formed of polyethylene. Referring to FIG. 15, in a state in which the plastic sheet 120 is adhered to the thin metal panel 110a, the rest portion of the thin metal panel 110a besides a portion corresponding to a button area is removed to form a metal pattern 112. Referring to FIG. 16, to form the metal pattern 112 corresponding to the button area, a masking pattern M is formed on the surface of the thin metal panel 110a. The masking pattern M is formed by a printing process using silicone or a light exposing process which selectively light exposes a photoresist layer, (b) The masking pattern M covers the area corresponding to the metal pattern 112 in order to protect the same. An etchant reacts on the thin metal panel 110a on which the masking pattern M is formed and the thin metal panel 110a is partially etched, thereby forming the metal pattern 112 on the plastic sheet 120. (c) The masking pattern M can be removed using a solvent, and only the metal pattern 112 remains on the plastic sheet 120. (d) According to circumstances, the masking pattern M is not removed to use as a button. Referring to FIG. 17, a transmission hole 114 formed in shapes of a number may be directly formed on the metal pattern 112 using the described method. Namely, a masking pattern in a shape of a number or a letter can be formed via an etching process using photoresists, and a hole formed around the number or letter on the metal pattern 112 using the masking pattern. The portion of the number or letter is etched to be formed in a hole shape on the metal pattern 112 adhered to the plastic sheet 120. Referring to FIG. 18, numbers or letters are designated on the metal pattern 112 of the button plate 100. Portions of numbers or letters can be formed by etching. The light of LED lamp transits the holes in shapes of the numbers or letters such as to discrimination signs designated on buttons at night. FIG. 19 is a cross-sectional view of a button plate according to another embodiment of the present invention. Referring to FIG. 19, a metal pattern 312 is formed on the top of a plastic sheet 320. The location of the metal pattern 312 may be on the plastic sheet 320 or below the plastic sheet 320 depending on the configuration of mobile phones. The metal pattern 312 is located on the top of the plastic sheet 320, and a protecting coating 316 can be formed on a button sheet 310 including the metal pattern 312. A rubber pad 330 including protruded portions 332 and interval supports 334 below the plastic sheet 320. As shown in FIG. 14, the metal pattern 312 can be adhered to the plastic sheet 320 without the protecting coating 316. The metal pattern 312 is located on the top of the plastic sheet 320, and the rubber pad 330 including the push protrusions 332 and the interval supports 334 below the plastic sheet 320. FIG. 21 is a cross-sectional view of a button plate 400 according to another embodiment of the present invention. Referring to FIG. 21, the button plate 400 includes a button sheet 410 including a metal pattern 412 and a plastic sheet 420. Push protrusions 432 and interval supports 434 are formed below the metal pattern 412 and the plastic sheet 420 and separated from each other without being connected by a rubber pad. The number of components can be reduced using the described configuration such as to decrease the total cost. The metal pattern 412 is formed on the bottom surface of the plastic sheet 420, and the push protrusions 432 and the interval supports 434 are formed by printing. Material of urethane or epoxy is used for printing material in order to print projected portions. The height of a projected portion including the push protrusions 432 and the interval supports 434 can be controlled in accordance with the size of a mesh of print screen. For example, the height may be increased according to the size of an interval of a mesh of print screen. FIG. 22 is a cross-sectional view of a button plate 500 according to another embodiment of the present invention. Referring to FIG. 22, the button plate 500 includes a button sheet 510 on which a metal pattern 512 is formed, a plastic sheet 520, push protrusions 532, and interval supports 534. Also, a button portion 518 can be formed to be projected on the top surface of a button area in which the metal pattern 512 is formed. The button portion 518 can be formed by printing using urethane or epoxy. The button portion 518 forms a projected portion on the plastic sheet 520 such as to keep the button area relatively high. FIG. 23 is a bottom view of a button plate 600 according to another embodiment of the present invention, and FIG. 24 is a sided-view illustrating the button plate 600 of FIG. 23 and a keystroke sensor part. Referring to FIGS. 23 and 24, the button plate 600 includes a button sheet 610 including a metal pattern 612, a plastic sheet 620, and push protrusions 632. A plurality of the push protrusions 632 are formed on the bottom surface of the metal pattern 612, and location can be elastically adjusted by forming the plurality of the push protrusions 632. Therefore, a manufacturing process can be conveniently maintained. As described above, push protrusions are disposed below a metal pattern and precisely adjusted to push the apex of a dome switch. However, when push protrusions are generally printed, push protrusions are not formed on a button plate one by one. Push protrusions are printed once on a sheet on which a plurality of the button plate is regularly arranged as a matrix, and the button plate is cut into the button plate via thomson-press. In this case, to precisely cut the button plate is not easy and it may occur frequently that a button plate is cut to be separated at a little interval. In this case, the location of push protrusions can be also changed to be wrongly cut, and a keystroke may not be smoothly performed. However, according to another embodiment of the present invention, the plurality of the push protrusions 632 are formed in a button area, and the dome switches 232 can be stably pushed using the plurality of the push protrusions 632. Also, since the plurality of the push protrusions 632 are formed, the dome switch 232 can be precisely pushed without hindrance if a predetermined deviation is generated in accuracy. In order to form the plurality of the push protrusions 632 on the bottom surface of the plastic sheet and the metal pattern 612, the push protrusions are printed using ultraviolet-cured resin on the bottom surface of the metal pattern 612 and ultraviolet is emitted to the printed ultraviolet-cured resin, thereby providing the push protrusions 632. Accordingly, when a location deviation between the button plate 600 and the dome switch 232 of the keystroke sensor part occurs, there is no problem to push the dome switch 232 because of the plurality of the push protrusions 632. In addition, push protrusions 632 can be directly formed on the plastic sheet 620 without the metal pattern 612, and dome switches can be directly pushed using the plastic sheet 620 and the push protrusions 632. When push protrusions are formed by a printing process, adhesive silicone ink can be used as a material forming push protrusions. Silicone rubber material as the material of push protrusions is printed in a dot shape in order to locate below a button area before push protrusions are thermally hardened, thereby forming push protrusions which are protruded from the bottom of a button in a dot shape and has elasticity. Otherwise, liquid silicone is extruded on the location of push protrusions through small holes for the size and the location of the push protrusions and hardened to be projected in a dot shape from the bottom of a button as elastic push protrusions. FIG. 25 is a sided-view of a button plate according to another embodiment of the present invention. Referring to FIG. 25, a plurality of push protrusions 632a is included, and a high hardness button pattern 612a is formed above a plastic sheet 620a. Push protrusions 632a are formed below the plastic sheet 620a using ultraviolet-cured ink, and the button pattern 612a which is not a metal but has higher hardness than the plastic sheet 620a above the plastic sheet 620a. The button pattern 612a can be formed using ultraviolet-cured ink and provided by printing method. FIG. 26 is a cross-sectional view of a button plate 700 according to another embodiment of the present invention, and FIG. 27 is a top view of the button plate 700 of FIG. 26. Referring to FIGS. 26 and 27, the button plate 700 includes a button sheet 710 including a metal pattern 712 and a plastic sheet 720 to which the metal pattern is adhered. The plastic sheet 720 is partially bent to form unevennesses, and the unevennesses function as push protrusions 732 to push a dome switch and interval supports 734 for supporting the intervals. Some portions of the plastic sheet 720 are projected downward to form the push protrusions 732, and other portions of the plastic sheet 720 are projected downward around the metal pattern 712 to form the interval supports 734. The plastic sheet 720 can be creased by pressing or thermal process to form the push protrusions 732 and the interval supports 734 without urethane or silicone printing. Generally, since the height of a dome switch is approximately 0.2 to 0.4mm, a distance that the interval support 734 is horizontally widened when a button is pushed is approximately 0.2 to 0.4mm. Though a distance is more than 1mm, the interval support 734 can be repeatedly transformed or restored sufficiently relaxed. The Shapes of push protrusions and interval supports can be variously changed. For example, a concave or a convex shape is possible, and a configuration in which a curve is formed vertically to a flat plastic sheet to be enlarged is possible. FIG. 28 is a cross -sectional view of a button plate according to another embodiment of the present invention. Referring to FIG. 28, the shape of push protrusions 732, and interval supports 734a and 734b can be variously formed such as in a vertical or a curved shape. Particularly, the interval supports 734a and 734b can be formed to be alternately arranged in an order of concave and convexity or concave or convexity. In this case, the interval supports 734a and 734b not only support an interval between the plastic sheet 720a and a dome switch but also bend the plastic sheet 720a to relax pushing of a button area. FIGS. 29 and 30 are cross-sectional views of button plates according to embodiments of the present invention. Referring to FIG. 29, a button plates 700b includes a button sheet 710b including a metal pattern 712b and a plastic sheet 720b to which the metal pattern 712b is adhered. The plastic sheet 720b is partially bent to form unevennesses, and the unevennesses function as push protrusions 732b to push a dome switch and interval supports 734b for supporting intervals. Some portions of the plastic sheet 720b are projected downward to form the push protrusions 732b, and other portions of the plastic sheet 720b are projected downward around the metal pattern 712b to form the interval supports 734b. The plastic sheet 720b can be creased by pressing or thermal process to form the push protrusions 732b and the interval support 734b without printing using urethane or silicone. Also, referring to FIG. 30, some portions of a plastic sheet 720c are projected downward to form push protrusions 732c, and other portions of the plastic sheet 720c are successively protruded downward around a metal pattern 712c to form the interval supports 734c having a double bend. FIG. 31 is an exploded perspective view of a button plate 800 according to another embodiment of the present invention. Referring to FIG. 31, the button plate 800 includes a plastic sheet 820, an absorbing rubber layer 840, a light emitting sheet 850, a button sheet 810, and a rubber pad 830. The button sheet 810 includes a sheet body formed using a thin metal panel, and separating slits 816 are formed in the sheet body to move a button pattern 812 up and down. The absorbing rubber layer 840 is interposed between the button sheet 810 and the plastic sheet 820. The absorbing rubber layer 840 provides soft touch when a button portion of the plastic sheet 820, in which numbers and letters are printed is pushed because of elasticity of rubber. The plastic sheet 820 on which a button area is printed according to a predetermined design is provided. Liquid rubber is injected into a mold in which the plastic sheet 820 is deposited to mold rubber bulk in accordance with the mold before hardened naturally or using thermal or ultraviolet, thereby forming the absorbing rubber layer 840. The light emitting sheet 850 is interposed between the absorbing rubber layer

840 and the button sheet 810. The plastic sheet 820 and the button sheet of a metal are used, thereby interposing the light emitting sheet 850 using electricity. The light emitting sheet 850 can be formed of an inorganic EL sheet or an organic EL sheet. Particularly, an inorganic EL sheet is used as a back light of conventional mono color LCD and can emit light of various colors. A metal panel is equipped with the light emitting sheet 850, thereby forming a light emitting key of numbers or letters. In the present invention, though the light emitting sheet 850 as a luminous layer is interposed between the button sheet 810 and the plastic sheet 820, otherwise, a luminous layer is directly formed on the button sheet 810. In this case, a luminous portion can be adhered corresponding to a button, or directly formed using a method of forming a luminous layer and luminous pattern as used in manufacturing semiconductor devices.

Industrial Applicability Since a button plate is composed of a thin high hardness button pattern and a plastic sheet such as to be formed to a thickness of approximately 0.05 to 1mm. Accordingly, a button plate minimizes the thickness of a keystroke part of a personal portable device and prevents hardness from getting more fragile as the thickness gets thinner. Also, not only the thickness of a keystroke part but also the thickness of a personal portable device can be notably reduced. Also, a button sheet and a plastic sheet can be manufactured at a time via mutual adhesion process, and a button plate is directly fixed into a key pad hole, thereby directly manufacturing a keystroke part. Also, since plastic sheets can be represented in various designs and colors using conventional printing methods, plastic sheets can have more various button shapes than conventional keystroke parts in which button shapes are molded respectively and can be manufactured at very low costs. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

1. A personal portable device comprising: a body including a key pad hole; a button plate installed at the body in which the key pad hole is formed, the button plate including a high hardness button sheet formed of a high hardness material and having a button pattern, each of the button patterns arranged in response to a button area for keystroking, and a plastic sheet formed adjacent to one side of the high hardness button sheet and connecting the button patterns each other; and a keystroke sensor part disposed below the button plate and including a push sensor generating input signal in response to the movement of each of the button patterns.

2. The personal portable device of claim 1, wherein the body includes a front case for installing the button plate and the keystroke sensor part and a rear case in response to the front case, and the key pad hole is formed in the front case in accordance with an external shape of the button plate.

3. The personal portable device of claim 1, wherein: a location guide projection is formed adjacent to the outline of the key pad hole on the inner surface the front case, and a location guide hole is formed in response to the location guide projection in the button plate.

4: The personal portable device of claim 1, wherein the button patterns of the high hardness button sheet is formed using one of a metal and material with higher hardness than the plastic sheet.

5. The personal portable device of claim 1, wherein at least one separating slit is formed around each of the button patterns at the high hardness button sheet.

6. The personal portable device of claim 5, wherein the separating slits are formed on both surfaces facing each other around the button pattern.

7. The personal portable device of claim 5, wherein since the separating slit is formed around the each of the button patterns, one portion of each of the button patterns is physically connected with the high hardness button sheet and the other portions of each of the button patterns are separated by a predetermined interval, so as to be in a cantilever shape.

8. The personal portable device of claim 1, further comprising: a push protrusion provided below the high hardness button sheet and formed in response to the button pattern below the same; and an interval support formed around the push protrusions and keeping an interval between the push protrusions and the push sensors.

9. The personal portable device of claim 1, further comprising a rubber pad including a push protrusion provided below the high hardness button sheet and formed in response to the button pattern below the same and an interval support formed around the push protrusions to keep an interval between the push protrusions and the push sensors.

10. The personal portable device of claim 9, wherein the plastic sheet and the rubber pad are adhered to the high hardness button sheet to be formed in a single body.

11. The personal portable device of claim 1 , wherein a push protrusion is formed by projecting one portion of the plastic sheet downward in response to each of the button patterns, and an interval support is formed in a uneven shape by bending another portion of the plastic sheet, around each of the button patterns, the interval support keeping an interval between the push protrusion and the push sensor.

12. The personal portable device of claim 11, wherein the unevennesses forming the interval supports are formed to protrude toward one of top, bottom, and top and bottom.

13. The personal portable device of any one of claims 8 to 12 wherein a plurality of the push protrusions are formed in response to the button pattern.

14. The personal portable device of claim 1, wherein the button patterns are formed on one of the bottom surface and the top surface of the plastic sheet.

15. The personal portable device of claim 14, wherein a protecting coating is formed above the button patterns positioned on the top surface of the plastic sheet.

16. The personal portable device of claim 1, wherein a light emitting layer is interposed between the plastic sheet and the high hardness button sheet.

"17. The personal portable device of claim 16, wherein the light emitting layer includes a light emitting sheet, and the light emitting sheet is interposed between the plastic sheet and the high hardness button sheet.

18. The personal portable device of claim 16, the light emitting layer is formed above the high hardness button sheet.

19. A button plate formed in a single body and installed in a key pad hole of a personal portable device to provide a keystroke part, the button plate comprising: a button pattern arranged in response to a button area for keystroking; a high hardness button sheet formed of a high hardness material; and a plastic sheet formed on one side of the high hardness button sheet and connecting the button pattern to each other.

20. The button plate of claim 19, wherein a location guide hole is formed around the outline of the plastic sheet.

21. The button plate of claim 19, wherein the button pattern of the high hardness button sheet is formed of one of a metal and a material with a higher hardness than the plastic sheet.

22. The button plate of claim 19, wherein at least one or more slits separating slits are formed around the button pattern at the high hardness button sheet.

23. The button plate of claim 22, wherein the separating slits are formed on both sides facing each other around the button pattern.

24. The button plate of claim 22, wherein since the separating slit is formed around the button pattern, one side of the button pattern and the high hardness button sheet are formed in a single body and the other sides of the button pattern are formed in a cantilever shape separated by the separating slit.

25. The button plate of claim 19, further comprising: a push protrusion provided below the high hardness button sheet and formed in response to the button pattern below the same; and an interval support formed around the push protrusion and keeping an interval between the push protrusions and the push sensors.

26. The button plate of claim 19, further comprising a rubber pad including a push protrusion provided below the high hardness button sheet and formed in response to the button pattern below the same and an interval support formed around the push protrusion and keeping an interval between the push protrusion and the push sensor.

27. The button plate of claim 26, wherein the plastic sheet and the rubber pad are formed in a single body adhered to the high hardness button sheet.

28. The button plate of claim 19, further comprising: push protrusions provided below the high hardness button sheet and formed by projecting some portions of the plastic sheet downward in response to the each of the button patterns; and interval supports formed by bending some portions of the plastic sheet to form unevennesses, the interval support keeping an interval between the push protrusions and the push sensors.

29. The button plate of claim 28, wherein the unevennesses forming the interval supports are formed to protrude toward one of top, bottom, and top and bottom.

30. The button plate of any one of claims 25 to 29, wherein a plurality of the push protrusions are formed in response to the button pattern.

31. The button plate of claim 19, wherein the button pattern is formed on one of the bottom surface and the top surface of the plastic sheet.

32. The button plate of claim 31, wherein a protecting coating is formed above the button pattern formed on the top surface of the plastic sheet.

33. The button plate of claim 19, wherein a light emitting layer is interposed between the plastic sheet and the high hardness button sheet.

34. The button plate of claim 33, wherein the light emitting layer includes a light emitting sheet, and the light emitting sheet is interposed between the plastic sheet and the high hardness button sheet.

35. The button plate of claim 33, wherein the light emitting layer is formed above the high hardness button sheet.