JP2006107970A - Manufacturing method for push button unit for portable telephone, and push button unit for portable telephone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow all key tops to be connected to a sheet material into an aggregate form so that individual key tops are not separated until the key tops are bonded to plate-shaped rubber, and to separate and remove an unwanted sheet material manually and simply after the key tops are bonded to the plate-shaped rubber. <P>SOLUTION: A resin sheet 3 is placed on contact surfaces of upper and lower metal molds 21 and 22, resins are injected into cavities 24 connected to the resin sheet 3, and then the key top shape is welded to the resin sheet 3 for integral formation. The injection of the resins into the cavities 24 is performed from small-diameter openings 27a formed on the side of the resin sheet 3 opposite to the side where the cavities 24 are formed, and performed by forming small holes in the resin sheet 3 by the jet pressure of the resin. Subsequently, a slit smaller in depth than the thickness of the resin sheet is formed by laser processing around the base end of the key top shape, then bonding to the plate-shaped rubber is performed and the unwanted resin sheet is removed by being separated at the slit portion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a push button unit for a mobile phone and a push button unit for a mobile phone manufactured by the method.

  A push button (key top) of a cellular phone is formed of a resin molded product, and is molded into an oval or a substantially rectangular shape having a small size that can be pressed with a fingertip. Then, a plate-like rubber is pasted on the back surface of the push button so that the user feels an appropriate elasticity when the push button is pressed and the switch is surely switched.

  In order to increase the elasticity when the push button is pressed, the plate-like rubber is formed in a convex shape in which the push button attaching portion is raised upward. In addition, the push button is usually attached to the rubber plate using an adhesive. In recent years, UV curable adhesives have been adopted as the adhesive to be used because of its good workability and short time to cure. Has been.

  An intermediate product in which a plurality of key tops are attached in a vertical and horizontal direction on a plate rubber is called a push button unit.In the manufacturing process of a mobile phone, this push button unit is used to increase work efficiency. It is literally assembled as a unit by inserting it into the casing of the mobile phone.

Conventionally known methods for manufacturing such a push button unit or push button panel are as follows. For example, a sheet member previously opened at a position where a key button is to be formed is stored in a mold, a key button molded product is formed using a material fused to the sheet member, and the sheet member and the key button are formed. A method of taking out a molded product from a die as it is (Patent Document 1), a method of laminating a plastic panel by using a die provided with a cavity into which a plastic sheet material can be inserted, and injecting a resin on the back surface of the sheet material (Patent Document 2). Further, a technique is known in which a key top before being attached to a plate rubber is created as a single sheet in which a plurality of key tops are formed on a single sheet (Patent Document 3).
JP-A-3-5129 JP-A-6-328506 JP 2001-126777 A

  As described above, the push button unit handles a large number of small key top parts in its manufacturing process, so that the individual key top parts do not fall apart until just before being attached to the plate rubber, For example, it is preferable that all the key top parts are assembled by being backed by a sheet material.

  For example, in the technique described in Patent Document 1 described above, a sheet member that is previously opened at a position where a key button is formed is stored in a mold, and the collar portion is fused to the sheet member. Thus, the key button molded product is integrally formed, and the key button molded product is adhered to the elastic sheet while being integrally formed. In this technology, since a large number of key buttons integrally formed on the sheet member are handled as an assembly, the handling is convenient, but the sheet member is not removed even after the key buttons are attached to the elastic sheet. Since it remains in the housing, the thickness of the product (cell phone) increases accordingly, and there is a disadvantage that is incompatible with the direction of reduction in size and weight. Further, after the key buttons are attached to the elastic sheet, a dedicated separating jig is required to separate the individual key buttons from the sheet member.

  The technology described in Patent Document 2 is a technology for manufacturing a plastic panel having a large number of push buttons by integrally forming a plastic protrusion or the like on the back surface of a plastic sheet material. It is not temporarily provided to collectively support the button parts, but rather the surface itself of the plastic sheet material constitutes the push button, and in the technology that can be directly applied to the manufacture of the push button unit of the mobile phone Absent.

  Further, the technique described in Patent Document 3 is convenient to handle because a large number of finger contact portions (corresponding to key tops) are collectively formed on a single sheet. It is not cut only and finally separated into individual finger contact portions.

  In view of the above circumstances, in the manufacturing method of the push button unit, the present invention provides all the key top components so that the individual key top components do not fall apart until the key top components are attached to the plate rubber. Can be connected to the sheet material, and after being attached to the plate rubber, the unnecessary sheet material can be separated and removed by simple manual work, removing the unnecessary sheet material Therefore, it is an object of the present invention to provide a push button unit manufacturing method and a push button unit that can make a completed cellular phone small and light.

  In order to achieve the above object, the invention of claim 1 is a method of manufacturing a pushbutton unit for a mobile phone in which a plurality of key tops are provided side by side in a horizontal direction and a vertical direction. After placing the resin sheet, the resin is injected into a cavity forming a key top shape connected to the resin sheet, and the resin injected into the cavity is a material that can be welded to the resin sheet. The key top shape is integrally formed with the resin sheet by welding, and the resin is injected into the cavity by the resin jetting pressure from the side opposite to the side where the cavity is formed with the resin sheet interposed therebetween. After that, a slit that is shallower than the thickness of the resin sheet is formed around the joint with the key-top resin sheet. Formed by The process, as well as adhering the key top integrally formed on the resin sheet to the plate-like rubber, and removing to separate unnecessary resin sheet in the slit portion.

  The invention of claim 2 is a push button unit for a mobile phone manufactured by the method of claim 1.

  According to the present invention, until the key top parts are attached to the plate rubber, a number of key top parts are connected by the sheet material and are easy to handle, and after being attached to the plate rubber, Since unnecessary sheet material can be separated and removed by simple manual work without the need for jigs, etc., work efficiency can be improved, and unnecessary sheet material can be removed, so it is completed Mobile phones can be made smaller and lighter. In addition, since the resin is injected into the cavity forming the key top shape from the side opposite to the side where the cavity is formed with respect to the resin sheet, the resin injection trace does not remain on the surface of the formed key top, and the resin A beautiful key top can be obtained without the need for a finishing step to erase the injection mark.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a molded product (hereinafter referred to as a sheet molded product) 1 in which a plurality of key tops are integrally formed on a resin sheet will be described. FIG. 1 shows a plan view of a sheet molded product 1 taken out from a molding machine after injection molding using a mold described in detail later. In this embodiment, numerals 0 to 9 and symbols # and * are included. A total of twelve key top shapes 2 are molded integrally on a single PC (polycarbonate) sheet 3. A frame-like connecting portion 4 is formed around the outer periphery of the 12 key top shapes 2. An injection path 4a for injecting resin remains in a columnar shape at the corner of the frame-shaped connecting portion 4, but in a later step together with the frame-shaped connecting portion 4, a portion where 12 key top shapes 2 are formed To be separated. A small flange 2a is formed at the base end of each keytop shape 2 (FIGS. 2 and 3).

  Next, the metal mold | die for shape | molding the above-mentioned sheet molded product 1 is demonstrated based on FIG. The mold according to the present embodiment includes upper and lower molds 21 and 22, and a shallow cavity (first cavity) 23 in which the PC sheet 3 can be inserted and placed is provided on the contact surfaces of the upper and lower molds 21 and 22. Thus, a second cavity 24 for forming the key top shape 2 is provided in the upper mold 21 so as to be continuous with the first cavity 23. Similarly, the upper mold 21 is provided with a third cavity 25 for forming the frame-like connecting portion 4 so as to be continuous with the first cavity 23, and a resin injection path to the third cavity 25. 26 is provided.

  The lower mold 22 is provided with a resin injection path 27 so that the opening 27 a faces the peripheral edge of the second cavity 24. The opening 27a is a small-diameter opening that can open a through-hole in the PC sheet 3 disposed in the first cavity 23 due to the pressure of the resin ejected from the opening considerably. Is formed.

  Next, processes until the sheet molded product 1 is molded using the molds 21 and 22 will be described. First, after the PC sheet 3 is arranged in the first cavity 23, the upper and lower molds 21 and 22 are closed, and polycarbonate resin is injected from the resin injection path 26 and the resin injection path 27 at an appropriate pressure. At this time, the resin injected from the resin injection passage 27 opens the pores 28 (FIG. 2) penetrating the PC sheet by the ejection pressure because the opening 27a is formed with a small diameter. And injected into the second cavity 24. Since the polycarbonate resin injected into the second cavity 24 and the third cavity 25 is made of the same material as that of the PC sheet 3, they are welded to each other and solidified together. The solidified resin is taken out from the mold and becomes a sheet molded product 1. Since the opening 27a of the resin injection path is provided so as to face the peripheral edge of the second cavity 24, when the resin ejected from the opening 27a collides with the PC sheet 3, the PC sheet 3 Is bent upward in the second cavity 24 to reduce the jetting pressure, and the trouble that the PC sheet 3 cannot open the pores hardly occurs.

  Next, the sheet molded product 1 injection-molded as described above is placed at a predetermined position on a separately prepared plate-like silicon rubber 5, and only the key top shape 2 is bonded and fixed to the plate-like rubber 5. The process up to this will be described. Since the sheet molded product 1 is in the form of a sheet, it is convenient to handle. After being taken out from the injection molding machine, it is transported to a known CO2 laser beam machine (not shown) and subjected to the next processing. That is, the slit 6 is formed by the CO2 laser processing machine along the periphery of the small flange portion 2a of the PC sheet 3 at a depth about half the thickness of the PC sheet 3. As shown in the enlarged view of the portion where the slit 6 is formed in FIG. 3, the laser beam is irradiated from the back side of the PC sheet 3. That is, for example, the sheet molded product 1 is fixed to an appropriate jig so that the key top shape 2 faces downward, and the sheet molded product is fixed to a processing table of a CO2 laser beam machine, and this processing table is numerically controlled. By moving in the plane direction by computer control, the laser light moves while irradiating around the small flange 2a. At this time, in the case of a laser light source capable of moving the laser beam, the focal depth of the laser beam, and the pulse oscillation, the pulse period is adjusted so that the depth of the slit 6 formed in the PC sheet 3 is half of the sheet thickness. To be about. As described above, each key top shape 2 is connected to the sheet 3, but can be easily separated from the PC sheet 3 by a relatively weak force by an operator. This sheet is placed on the silicon rubber 5 as a sheet.

  As shown in the cross-sectional view of FIG. 5, the plate-like silicon rubber 5 has a portion in which the key top shape 2 is placed in advance in a convex shape 5 a, and this key top shape 2 placement position. The (convex position) corresponds to the position of each numeric keypad on the operation surface 11 operated by the user when the cellular phone finished product 9 (FIG. 6) is later obtained. FIG. 5 shows a cross section of the completed mobile phone 9 incorporating the push button unit 30 of the present embodiment (the cross section is the VV line of FIG. 6), and the wiring board 7 is disposed below the silicon rubber 5. A switch member 8 is disposed immediately below the convex shape 5a. Further, the upper part of the keytop shape 2 is exposed from a hole 10a formed in the casing 10 of the mobile phone 9, and serves as an operation part when the user performs a push operation.

  Since the plate-shaped silicon rubber 5 is configured in the above-mentioned shape, if the arrangement of the key top shape 2 on the PC sheet 3 is matched with the position of the convex shape 5a of the silicon rubber 5, one sheet molded product When the key top shape 2 connected as 1 is placed on the silicon rubber 5, each key top shape 2 is positioned on the corresponding convex shape 5a.

  In the present embodiment, as described above, the individual key top shapes 2 are placed at the positions of the appropriate convex shapes 5a on the silicon rubber 5, and bonded and fixed by the adhesive 12 at the positions, and then the PC sheet. 3 is peeled upward by the operator. At this time, since the PC sheet 3 and the key top shape 2 are merely connected by the shallow slit 6, the PC sheet 3 and the key top shape 2 are easily separated, and only the key top shape 2 is on the silicon rubber 5. Remain in. The unnecessary sheet portion peeled upward is discarded.

  Further, between the silicon rubber 5 and the key top shape 2 aligned as described above, an ultraviolet curable adhesive containing 0.2% silica (SiO 2 .nH 2 O) in particular by weight. No. 12 is applied, and ultraviolet rays are irradiated immediately thereafter to achieve strong adhesion. That is, in the present embodiment, an adhesive in which 0.2% by weight of silica is mixed in advance with an ultraviolet curable adhesive, and this is used as the upper surface of the convex shape 5a of the plate-like silicon rubber 5 or Then, it is applied to the bottom surface of the key top shape 2, the silicon rubber 5 and the sheet molded product 1 are bonded together as described above, and then the unnecessary sheet portion is peeled upward to obtain the push button unit 30.

  As described above, the push button unit 1 as an intermediate product in which the key top shape 2 is bonded and fixed to the predetermined position 5a on the plate-like silicon rubber 5 is completed. The mobile phone 9 is completed by being incorporated therein. In the completed mobile phone, the upper surface of the key top shape 2 is the operation surface for the push operation by the user. As described above, the resin is injected into the cavity 24 forming the key top shape 2 with respect to the resin sheet 3. Thus, since the resin injection trace is not left on the surface of the formed key top shape 2 and the finishing process for removing the resin injection trace is not required, it is beautiful. The key top 2 can be used.

  Further, since the slit 6 is formed using a CO2 laser processing machine, even the thin resin sheet 3 can be easily and in a short time around the base end portion of the key top shape 2 at a depth of about half the sheet thickness. The slits 6 can be formed correctly, and when the unnecessary sheet portion is peeled off, the separation part is not within the predetermined separation line, so that the trouble that separation is not good does not occur.

  While the sheet molded product 1 taken out from the mold is transferred to the laser processing machine, the numbers 0 to 9 and the symbols # and * are printed on the upper surface of the key top shape 2.

  Moreover, in the said embodiment, although a sheet molded product is transferred with the rectangular sheet form shown in FIG. 1 containing the frame-shaped connection part 4 until it mounts on the plate-shaped rubber 5, for example, After the top surface of the key top shape 2 is subjected to printing processing and then transferred to the laser processing machine, after the slit 6 is formed, the periphery of the key top 2 as an assembly is cut by laser light 31. Good. The example of the cutting line in that case is shown by the dashed-dotted line in FIG. In this case, since the on-frame connecting portion 4 is separated from the twelve key top shapes 2 as the aggregate, it is not bulky when the key top shape 2 as the aggregate is transferred onto the plate rubber 5, In addition to facilitating the transfer, the work of positioning and placing on the plate rubber 5 is facilitated.

The top view of the sheet molding manufactured by the manufacturing method concerning one embodiment of the present invention. Sectional drawing by the II-II line of FIG. The partially expanded sectional view of the sheet molded product. Sectional drawing which shows the metal mold | die used for manufacture of the sheet | seat molded product. The VV sectional view taken on the line of FIG. 6 which shows the state which incorporated the same pushbutton unit in the casing of a mobile telephone. The figure which shows the external appearance of the mobile telephone as a finished product.

Explanation of symbols

1 Sheet molded product 2 Key top shape 3 PC sheet (resin sheet)
5 Plate-like silicon rubber 6 Slit 9 Mobile phone 12 Adhesive 21 Upper mold 22 Lower mold 23 First cavity (cavity for placing resin sheet)
24 Second cavity (cavity for forming key top shape)
27 Resin Injection Path 27a Opening 28 Pore

Claims (2)

A method for manufacturing a push button unit for a mobile phone, in which a plurality of key tops are arranged in a horizontal direction and a vertical direction,
After placing the resin sheet on the contact surface of the upper and lower molds, inject the resin into the cavity forming the key top shape connected to the resin sheet,
The resin injected into the cavity is a material that can be welded to the resin sheet, and the resin injected into the cavity is integrally formed by welding the key top shape with the resin sheet,
The injection of the resin into the cavity is performed from the opposite side of the side where the cavity is formed, through the pores opened in the resin sheet by the resin jet pressure,
A slit shallower than the thickness of the resin sheet is formed by laser processing around the joint portion with the keytop-shaped resin sheet,
A method for manufacturing a pushbutton unit for a mobile phone, comprising: adhering a key top integrally formed on a resin sheet to a plate-shaped rubber; and separating and removing an unnecessary resin sheet at the slit portion.   A push button unit for a mobile phone manufactured by the method according to claim 1.

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