KR20040060495A - Keypad for cellular phone and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A keypad for a mobile phone use and a method for manufacturing the same are provided to shorten manufacturing time by synthetically pressing and molding flexible heat-resistant poly urethane-series film and silicon rubber in the same metallic mould so that the shape of a keypad can be made. CONSTITUTION: In assembling a keypad, keys(K) respectively are inserted into the holes formed at a front housing(H). A dome switch member(28), at which dome switches(26) are formed, is located at the lower part of the keypad. A PCB(Printed Circuit Board)(30) is located at the lower part of the dome switch member(28), and the PCB(30) is caught on hooking sills(32) formed at both sides of the front housing(H). The assembled keypad is fixed as support bars(34) formed in the inner side of the front housing(H) are inserted into the fixing holes(22) of the keypad and the fixing holes of the dome switch member(28).

Description

KEYPAD FOR CELLULAR PHONE AND MANUFACTURING METHOD THEREOF}

The present invention relates to a keypad for a mobile phone and a method of manufacturing the same, and more particularly, for a mobile phone that can produce a keypad easily and quickly by preventing the operation of the key from being lowered without performing a separate process using a flexible film. It relates to a keypad and a method of manufacturing the same.

In general, a communicator can be classified into a wired or wireless communicator, and a wired communicator is typically an office or home telephone, and a wireless communicator is a typical mobile phone.

Such a communicator has a key as a switch device for signal generation, and the key is inserted into a hole provided in the front housing of the telephone so that an upper portion of the key protrudes out of the front housing.

In most cases, a switch device of a mobile phone uses a dome switch to obtain a feeling of operation, and the dome switch is configured to generate a signal by contacting a contact provided on a printed circuit board by the above-described key operation.

The keys constituting the keypad are largely classified into a silicone rubber type whose mother body is made of a silicone rubber material and a film type molded from a synthetic resin.

Silicone rubber type keypad is made by injection molding silicone rubber into key shape and then printing letters on the upper surface of key top. Film type keypad is formed of synthetic resin into key shape and adhesive film with printed surface is formed on the formed key. How to make a keypad.

However, the silicone rubber type keypad is printed on the upper part of the key so that the printing is easily erased, and the film type keypad has a printed surface of the film located inward, so there is no erasure of printing, but the feel is good because the material is a hard synthetic resin. And lack of mechanical stability.

In addition, the film-type keypad is manufactured by injecting epoxy into the preformed film and then injecting silicone rubber into the film. The epoxy is a hard material through a curing process, so that the operability of the key is reduced as well. There is a disadvantage in that the production time of the keypad is lengthened by manufacturing the key in the same manner as described above.

In order to solve this disadvantage, the applicant has been granted a patent registration No. 0432959 on June 20, 2002.

The patent prints numbers or letters to match the arrangement of keys on a flat transparent film, presses the film with a press to have a key shape, and preforms the film, and then interferes with keys between the keys of the preformed film. A slit forming step is performed to prevent the damage.

Then, the liquid silicone rubber is discharged to the surface of the preformed film, and the discharged silicone rubber is compressed into a press in a mold, and the keypads are manufactured by processing each key into an integral keypad form.

However, the keypad as described above uses a polycarbonate or a similar kind of film, which is a kind of synthetic resin, so that the key interference prevention slits are formed on the molded film to prevent the keys from interfering with the key operation. Since the slit forming process is performed, there is a problem in that the manufacturing time of the keypad is lengthened.

In addition, the conventional keypad manufacturing method has a disadvantage in that the keypad manufacturing time is increased by performing an adhesive coating process so as to be adhered with the silicone rubber on the printing surface side of the film on which the printing surface is formed after performing the printing process on the film.

The present invention has been made to solve the problems as described above, the object of the present invention is to produce a flexible heat-resistant polyurethane-based film and silicone rubber by extrusion molding collectively to have the shape of the keypad in the same mold And a keypad for a mobile phone that can produce a keypad easily and quickly by manufacturing the keypad so as to prevent the operation of the key from being lowered without performing a separate process for forming the slit due to the flexible film. To provide a production method.

In order to realize the object of the present invention as described above, a printing step of printing a printing surface such as numbers and letters to fit the arrangement of keys on a flexible heat-resistant polyurethane-based film; A film preforming step of pressing the printed surface of the film with a press or the like to have a key shaped space; A silicon rubber ejecting process of ejecting a liquid silicone rubber onto a preformed film surface; A molding process of pressing the silicon rubber into a press in a mold to process the film and the silicon rubber into an integral keypad in which each key is connected to each other; The present invention provides a method for manufacturing a keypad for a mobile phone, including a cutting process of cutting an outer edge of the molded keypad according to a product shape.

The film preforming process is provided with a dome-shaped space so that the LED lamp located on the bottom of the key is located, and the film is molded to the same thickness and a predetermined temperature to prevent distortion of characters due to the forced expansion of the film. It is characterized by using a hot press heated with.

1 is a process chart showing a manufacturing method of a keypad for a mobile phone according to the present invention.

2a to 2d are cross-sectional views showing that the keypad is manufactured according to the process according to the present invention.

Figure 3a and Figure 3b is an exploded perspective view showing that the keypad manufactured by the present invention is assembled.

4 is a cross-sectional view showing that the keypad of the present invention is assembled to a mobile phone.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a process chart showing a method for manufacturing a keypad according to the present invention, first through a printing process (S1) for printing numerals or letters on a transparent film made of a flat surface.

In the printing process (S1) is to print on the back of the film, such a back printing is to maintain the printing durability by not directly contacting the print surface and fingers when using the mobile phone.

When the printing step (S1) is completed, the film is pre-formed into a key shape through the film preforming step (S2) to press the printed surface side of the film by a press or the like to have a key shape.

At this time, the dome-shaped space is also molded around the key so that the LED lamp for the back lighting function can be positioned around the keys.

In the film preforming process (S2), the printing surface printed on the film is positioned to be molded inward, and during the film preforming process (S2), the film is formed to have the flexibility to be molded to the same thickness while the text is not distorted. Hot press may be used or heat may be applied to the film surface.

The preformed film may be deteriorated in the operability of the key due to the rigid properties of the film, in order to prevent such a film is used in the heat-resistant polyurethane-based film having a flexible property of the film material.

By using such a heat resistant polyurethane film, it is possible to prevent the adjacent keys from being pressed or flowed together when the keys are pressed, and to make the key operation easier. This can replace the function of the slit in the prior art.

The film preformed in the shape of the key as described above is inserted into a mold having the same shape as the key, and then silicone rubber ejection step of filling the mother body of the key collectively using an automatic ejector for each key (S3). At this time, the liquid silicone rubber which is slightly larger than each key volume inserted into the mold is discharged.

Before performing the silicone rubber discharging step (S3), a process of coating an adhesive on the film may be inserted so that the film and the silicone rubber adhere well.

When the silicone rubber discharging step S3 is completed, another mold is placed on the mold to press the discharged silicone rubber to have a shape of a keypad. Each key portion includes these keys. Since more silicone rubber is injected than the volume of the silicone rubber is pressed into the mold, the silicone rubber spreads around the key and the keys, and each of the keys is connected to each other to form an integral keypad.

When the key is integrally formed as described above, mass production is possible in a short time as compared with molding each of the conventional keys, thereby reducing the manufacturing cost.

And since the liquid silicone rubber has an adhesive force, the film and the silicone rubber are in a state of being integrally bonded.

In addition, if the material of the key using the silicone rubber as described above, not only can be mechanically stable and smoothly operated, but also the soft feel of the silicone rubber can improve the feel of the key.

After the molding process (S4) is completed, the silicone rubber is cured for a certain time to harden, and then remove the outer edge portion to fit the shape of the mobile phone and the fixing hole so that the keypad can be fixed in the front housing of the mobile phone The manufacturing of the keypad is completed by performing the cutting step (S5) to form a.

Through this manufacturing process, the process of manufacturing the keypad will be described with reference to the drawings.

Figure 2 is a cross-sectional view showing a keypad manufactured according to the above process, Figures 3 and 4 is an exploded perspective view showing that the manufactured keypad is assembled, the keypad according to the present invention is approximately 0.25 as shown in Figure 2a Printing surfaces 4 such as letters and numbers are formed on one side of the transparent film 2 having a thickness of about mm to 0.5 mm.

The film 2 is a heat-resistant polyurethane-based film having a flexible characteristic in the present invention, due to this heat-resistant polyurethane film can prevent the adjacent keys are pressed together or flow when the key is pressed, the key The press operation of the can be made more smooth.

When the film 2 on which the printing surface 4 is formed is provided, as shown in FIG. 2B, a hot press (not shown) having a key shape in the direction in which the printing surface 4 is formed and heated to a predetermined temperature is provided. When the film 2 is pressed by use, the film having the space portion 6 made of the shape of the key is preformed.

At this time, the dome-shaped groove 8 is simultaneously formed around the key so that the LED lamp providing backlighting on the keypad can be located. By forming the groove 8, the space occupied by the LED lamp in the mobile phone is small. The thickness of the mobile phone can be reduced so that a compact mobile phone can be manufactured.

When this film preforming is completed, the film 2 preformed into a key shape is inserted into a mold having a groove of a key shape (not shown), and each space part 6 formed into a key shape is shown in Fig. 2C. As expressed by, the liquid silicone rubber 10 which is slightly larger than each key volume is discharged.

In this state, when another mold (not shown) having the same shape as the bottom of the key is placed above the main mold and the silicon rubber 10 is pressed, the key top 12 and the key top 12 are pressed as shown in FIG. 2D. The key K which has the contact protrusion 14 which protruded in the opposite center part of this, and the skirt 16 located in the outer side of this contact protrusion 14 is shape | molded.

At this time, the LED lamp is formed so as to have a hole 18 communicating with the groove 8 formed in the film 2, each key (K) is made of a single body to form a form connected to each other by the connecting portion (20). Molding in a state.

In this molding, the film 2 and the liquid silicone rubber 10 having adhesive strength are firmly adhered to each other, so that the key K, the connecting portion 20 and the film 2 constituting the keypad are integrally formed. do.

In this way, if the keypad is manufactured integrally in the same mold, it is possible not only to shorten the manufacturing time of the keypad, but also easily and quickly when assembling the keypad on a mobile phone.

And the skirt 16 formed in the key (K) is to operate more smoothly when operating the key (K), providing a resilience to improve the feel of the key, as well as after the key (K) operation Improve resilience

When the key is molded as described above, the outer portion of the keypad is cut to fit the shape and size of the mobile phone, and the production of the keypad is completed by punching a plurality of fixing holes 22 so that the keypad can be fixed in the mobile phone.

The completed keypad is assembled by inserting the keys K into the respective holes 24 formed in the same manner as the arrangement of the keys K in the front housing H of the mobile phone as shown in FIGS. 3 and 4.

In addition, a dome switch member 28 having a dome switch 26 having the same arrangement as that of the key K is disposed below the keypad, and a printed circuit board 30 is disposed below the dome switch member 28. In the positioned state, the printed circuit board 30 is assembled by being caught by the latching jaw 32 formed on both sides of the front housing H. As shown in FIG.

The keypad thus assembled is fitted with a fixing hole 22 of the keypad and a fixing hole 36 of the dome switch member 28 in a support 34 formed inside the front housing H of the telephone to maintain a fixed state.

The contact protrusions 14 formed on the respective keys K are in surface contact with the dome switch 26 installed on the printed circuit board 30, and the keys K and the holes between the keys are holes in the front housing H. The keypad 24 is brought into contact with the bottom of the hole 24 so that the keypad can be held in the front housing H.

When the keypad for the cellular phone assembled as described above, when the key K is pressed, the protrusion 14 formed on the bottom of the key K overcomes the elasticity of the dome switch 26 and moves downward to elastically move the printed circuit board ( A signal is generated by contacting a contact formed on 30).

When the signal K is released after the signal is released, the dome switch 26 and the key K are raised to the resilient elasticity and return to their original position.

As described above, the method for manufacturing a keypad for a mobile phone according to the present invention reduces the manufacturing time of the keypad by shortening the production time by collectively extruding the film forming the outside of the key and the silicone rubber forming the parent of the key in the same mold. Can be saved.

In addition, since the film constituting the outside of the key using a flexible heat-resistant film to prevent the adjacent key is pressed when using the key can be accurate key operation can improve the reliability of the keypad.

In addition, since the printing surface is positioned inside the film, the printing surface can be prevented from being damaged and the printing durability can be maintained.

Claims (4)

A printing step of printing a printing surface such as numbers or letters on the flexible heat-resistant polyurethane-based film to match the arrangement of the keys; A film preforming step of pressing the printed surface of the film with a press or the like to have a key shaped space; A silicon rubber discharge step of discharging the liquid silicone rubber onto the preformed film surface; A molding process of pressing the silicon rubber into a press in a mold to process the film and the silicon rubber into an integral keypad in which each key is connected to each other; Method of manufacturing a keypad for a mobile phone, including a cutting process of cutting the outer edge of the molded keypad to the shape of the product. The method of claim 1, wherein the printing process forms a printing surface on the back of the film. The keypad of claim 1, wherein the film preforming process uses a hot press heated to a predetermined temperature to maintain a constant thickness of the film and to prevent distortion of characters due to forced expansion of the film. How to make. In a keypad for a mobile phone which is positioned on a printed circuit board having a contact point and protrudes a predetermined height outside the hole provided in the front housing of the telephone, and is used as a switch device for signal generation. The keypad is a keypad for a mobile phone in which a flexible heat-resistant polyurethane film is molded into a key shape, and the key-shaped film is integrally bonded with a liquid silicone rubber.