JP5144436B2 - Key mat, method for manufacturing the key mat, and electronic device using the key mat - Google Patents

Description

  The present invention relates to a key mat, a method for manufacturing the key mat, and an electronic device using the key mat.

  In order to satisfy the demands of users of electronic devices, manufacturers are striving to reduce the thickness of electronic devices and extend their service life. Usually, a thin-walled key mat is used to reduce the thickness of the electronic device, and a key mat in which a thermoplastic polyurethane film (Thermoplastic Polyurethane, abbreviated as TPU film) is used in the skirt portion in order to extend the service life.

  FIG. 1 is a side view of a prior art key mat 1. The key mat 1 includes a key top 11, a key support part 13, and a light guide part 14. The key top 11 is manufactured from polycarbonate (abbreviated as PC material). The key support portion 13 is bonded to the bottom surface of the key top 11 with an adhesive 15. The key support portion 13 includes a main body 131, at least two skirt portions 133, at least two attachment portions 135, and a connection portion 137. The light guide unit 14 is integrally bonded to both sides of the key support unit 13. The light guide unit 14 has an effect of guiding light rays (not shown) of a backlight installed on the key mat 3.

  The skirt portion 133 is formed to extend from the bottom surface of the main body 131 to both sides. The thickness of the skirt portion 133 is significantly smaller than the thickness of the main body 131, and the elastic force is good. When the key support portion 13 is deformed, the key support portion 13 can return to its original shape by the elastic force of the skirt portion 133. The mounting portion 135 is formed substantially perpendicular to the bottom surface of the skirt portion 133. When the electronic device is assembled, the key support portion 13 is engaged with a cover (not shown) of the electronic device. The connection part 137 protrudes substantially perpendicularly to the approximate center of the main body 131. When the connection part 137 moves downward, a metal dome (not shown) mounted inside the electronic device is pushed.

  When the key mat 1 is used, the key top 11 is pushed by hand. The key support portion 13 is moved downward by the key top 11 while overcoming the elastic force of the skirt portion 133. The connecting portion 137 formed on the bottom surface of the key support portion 13 moves together with the key support portion 13 together. When the connecting portion 137 moves downward, it is connected to a circuit board (not shown) inside the electronic device, so that the circuit board switch may be turned on (ON) or turned off (OFF). it can.

  When the key support portion 13 moves downward, since the thickness of the skirt portion 133 is smaller than the thickness of the main body 131, the skirt portion 133 is deformed first and deformed the most. In other words, since the thickness of the skirt portion 133 is smaller than that of the main body 131 and the amount of deformation is larger than that of the main body 131, the life of the skirt portion 133 is further shorter than other portions. That is, when the key mat 1 is used for a long time, the skirt portion 133 having a small thickness is broken first, so that the service life of the key mat 1 is shortened.

  In order to increase the service life of the skirt portion 133, a TPU film 139 can be installed on the skirt portion 133. The TPU film 139 is tightly bonded on the skirt 133 and the main body 131. Since the tensile strength of the TPU film 139 is high and the TPU film 139 is closely bonded to the skirt portion 133, the strength of the skirt portion 133 can be improved and the service life can be extended.

  However, since the TPU film 139 is easily shrunk when heated, the dimensions of the TPU film 139 cannot be easily controlled when the key mat 1 is manufactured by the insert molding method. That is, since the dimensional stability of the TPU film 139 is poor, the dimensional accuracy and quality of the key mat 1 are deteriorated.

  In view of the above problems, an object of the present invention is to provide a key mat having a long service life and good dimensional stability, a method for manufacturing the key mat, and an electronic device using the key mat.

In order to solve the above problem, a key mat including a key top, a key support part installed on the bottom surface of the key top, and light guide parts installed at both ends of the key support part is provided. In the key mat, the key support part is formed to extend from the bottom surface of the main body to both sides and has a thickness that is thinner than the main body, and projects perpendicularly to the bottom surface of the main body. And a connection portion for connecting to a circuit board inside the electronic device when moving downward. A mesh-like woven fabric is provided on the light guide portion and the skirt portion.

In order to solve the above problems, a step of providing a mold including a female mold having a first insertion mold and a second insertion mold , a first male mold, and a second male mold; Inserting a fabric between the first male mold, and inserting the first insertion mold into the female mold, and then inserting the first male mold into the female mold to form a first cavity. And a step of injecting a resin into the first cavity to form a light guide, and inserting the second insertion mold into the female mold instead of the first insertion mold, and replacing the first male mold After the second male mold is inserted into the female mold, the female mold and the second male mold are brought close to each other to form a second cavity, and silicone is injected into the second cavity to support the key. Forming a portion; and bonding a key top on the key support portion that has been molded; and Method of manufacturing a key mat, characterized in that it comprises.

In order to solve the above problem, an electronic device to which a key mat is attached is provided. In the electronic device, the key mat includes a key top, a key support portion installed on a bottom surface of the key top, and light guide portions installed on both ends of the key support portion, and the key support portion. time, is formed by extending a body, from the bottom of the body on both sides, and that the thickness of said body thinner least two skirt portions are projected perpendicularly to the bottom surface of the body, to and moves downward wherein a connecting portion for connecting the internal circuit board of an electronic device, wherein the wherein the light guide portion and the skirt portion, characterized in that the mesh fabric is provided.

  As described above, the woven fabric is formed on the skirt portion. Since the fabric has a high tensile strength and is closely adhered to the skirt portion of the key support portion, the tensile strength of the skirt portion is increased and the service life is extended. That is, even if the key mat is used for a long time, the skirt portion is not broken, so that the service life of the key mat can be extended. In addition, since the fabric does not shrink even when heated, the dimensions can be easily controlled and the quality can be improved.

  Hereinafter, a key mat according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a cross-sectional view of the key mat 3 according to the embodiment of the present invention. The key mat 3 includes a key top 31, a key support portion 33, at least two light guide portions 34, and a mesh-like fabric 37 formed inside the key support portion 33 and the light guide portion 34. Including. In the present embodiment, the electronic device refers to a mobile phone, a personal digital assistant (abbreviated as PDA), and the like.

  The key top 31 is made of a resin such as polycarbonate (abbreviated as PC) or polymethylmethacrylate (abbreviated as PMMA). The key top 31 is formed with patterns such as letters and numbers for identification by the user of the electronic device.

  The key support portion 33 is made of silicone and is bonded to the bottom surface of the key top 31 with an adhesive 35. The key support portion 33 includes a main body 331, at least two skirt portions 333, at least two attachment portions 335, and a connection portion 337.

  The main body 331 is located in the upper part of the key support portion 33. The skirt portion 333 is formed to extend from the bottom surface of the main body 331 to both sides. The thickness of the skirt portion 333 is smaller than the thickness of the main body 331, and the elastic force is good. When the key support portion 33 is deformed, the key support portion 33 can return to its original shape by the elastic force of the skirt portion 333. The mounting portion 335 is formed substantially perpendicular to the bottom surface of the skirt portion 333. When assembling, the mounting portion 335 engages with a cover (not shown) of the electronic device, so that the key support portion 33 is fixed. The connection portion 337 protrudes substantially vertically near the center of the main body 331. When the connection part 337 moves downward, a metal dome mounted inside the electronic device is pushed (not shown).

  The light guide part 34 is formed on both sides of the key support part 33. That is, it is integrally connected to the side surface of the mounting portion 335 so as to be parallel to the mounting portion 335. The light guide part 34 is made of a resin such as PC or PMMA like the key top 31 and has an effect of guiding a light beam (not shown) of a backlight installed on the key mat 3.

  The woven fabric 37 is a mesh-shaped woven fabric formed from a cloth or the like. The fabric 37 is integrally formed inside the main body 331, inside the skirt portion 333, and inside the light guide portion 34 so as to be parallel to the extended surfaces of the two opposing skirt portions 333. In this embodiment, the fabric 37 is integrally formed by an insert molding method. When the key mat 3 is molded by an insert molding method, the silicone forming the key support portion 33 enters the mesh hole of the fabric 37, so that the key support portion 33 and the fabric 37 are closely bonded. That is, the fabric 37 is tightly bonded to the skirt portion 333 of the key support portion 33. In addition, since the resin forming the light guide portion 34 also enters the mesh hole of the fabric 37, the light guide portion 34 and the fabric 37 are closely bonded.

  As described above, the fabric 37 is tightly bonded to the inside of the main body 331 and the inside of the skirt portion 333. Since the fabric 37 has a high tensile strength and is tightly bonded to the skirt portion 333 of the key support portion 33, the skirt portion 333 has a high tensile strength and a long service life. That is, even if the key mat 3 is used for a long time, the skirt portion 333 is not broken, so that the service life of the key mat 3 can be extended. In addition, since the fabric 37 does not shrink even when heated, when the key mat 3 is manufactured, the dimensions can be easily controlled to improve the quality.

  FIG. 3 is a side view of a key mat 5 according to another embodiment of the present invention. The key mat 5 includes a key top 51, a key support portion 53, at least two light guide portions 54, and a mesh fabric 57 formed at a predetermined portion of the key support portion 53. The key support portion 53 is bonded to the bottom surface of the key top 51 with an adhesive 55, and includes a main body 531, at least two skirt portions 533, at least two mounting portions 535, and a connection portion 537.

  3 is different from the key mat 5 of FIG. 2 in that the connection portion of the main body 531 and the skirt portion 533 and the connection of the skirt portion 533 and the mounting portion 535 are different. The chamfer is applied to the part. To simplify manufacturing, it is better to make the two chamfer radii the same.

  In the key mat 5 shown in FIG. 3, a fabric 57 molded by an insert molding method is tightly bonded inside the skirt portion 533. Since the fabric 57 has a high tensile strength and is tightly bonded to the skirt portion 533 of the key support portion 53, the tensile strength of the skirt portion 533 is increased and the service life is extended. That is, even if the key mat 5 is used for a long time, the skirt portion 533 is not broken, so that the service life of the key mat 5 can be extended. In addition, since the fabric 57 does not shrink even when heated, when the key mat 5 is manufactured, the dimensions can be easily controlled to improve the quality.

  In addition, since chamfering is formed at the connecting portion between the main body 531 and the skirt portion 533 and the connecting portion between the skirt portion 533 and the mounting portion 535, it is possible to prevent stress from being generated at the connecting portion. The service life of 533 can be further extended. That is, even if the key mat 5 is used for a long time, the skirt portion 533 is not broken, so that the service life of the key mat 5 can be extended.

  FIG. 4 is a perspective view of the electronic device 7 according to the embodiment of the present invention. The electronic device refers to a mobile phone, a personal digital assistant (abbreviated as PDA), and the like. In the present embodiment, a mobile phone 7 will be described as an example. A plurality of key mats 71 for inputting numbers and the like, a display device 73 for displaying images, and the like are installed on the upper surface of the mobile phone 7. The key mat 71 is the same as the key mat structure shown in FIG. 2 or 3 and will not be further described.

  Hereinafter, a process for producing the key mat of the present invention by an insert molding method will be described in detail with reference to the drawings.

  In FIG. 5, the mold 8 is opened, and the fabric 91 is supplied into the mold 8. The fabric 91 is supplied to the fabric feeder 80 and guided to a predetermined position by a sensor (not shown) installed in the mold 8. The mold 8 includes a female mold 81, a first male mold 83, a second male mold 85, and a first insertion mold 811 and a second insertion mold 813 that are inserted into the female mold 81. The woven fabric 91 is a mesh-shaped woven fabric formed from a cloth or the like.

  In the mold 8 shown in FIG. 6, the first male mold 83 is inserted into the female mold 81 after the first insertion mold 811 is inserted into the female mold 81 (or simultaneously with the insertion). Next, the female die 81 and the first male die 83 are brought close to each other to form a first cavity between them. Next, a resin such as polycarbonate or polymethyl methacrylate is injected into the first cavity to form a light guide portion 93 (see FIG. 8). Thus, the resin forming the light guide portion 93 enters the mesh hole of the fabric 91, so that the light guide portion 93 and the fabric 91 are closely bonded.

  In FIG. 7, after the first insertion die 811 is retracted from the female die 81, the second insertion die 813 is inserted into the female die 81. In addition, after the first male mold 83 is retracted from the female mold 81, the second male mold 85 is inserted into the female mold 81. Next, the female mold 81 and the first male mold 83 are brought close to each other to form a second cavity therebetween. In addition, a material such as silicone is injected into the second cavity to form a key support portion 95 (see FIG. 8). Thus, since the material forming the key support portion 95 enters the mesh hole of the fabric 91, the key support portion 95 and the fabric 91 are closely bonded. Since the molten silicone material is injected, the key support portion 95 and the light guide portion 93 are bonded together. That is, the light guide part 93 is integrally formed at both ends of the key support part 95.

  In FIG. 8, after the injection process is completed, the second male mold 85 is retracted from the female mold 81, and the key support portion 95 to be molded is taken out.

  In FIG. 9, the key top 97 is bonded on the key support portion 95 to be molded. In the present invention, the key top 97 is bonded onto the key support portion 95 with an adhesive, but a welding method in other embodiments can also be used.

  In the key mat manufactured by the method described above, the fabric 91 is tightly bonded to the inside of the key support portion 95 and the inside of the light guide portion 93. Since the fabric 91 has a high tensile strength and is closely bonded to the key support portion 95, the tensile strength of the key support portion 95 is increased and the service life is extended. That is, even if the key mat is used for a long time, the key support portion 95 is not broken, so that the service life of the key mat can be extended. In addition, since the fabric 91 does not shrink even when heated, the dimensions can be easily controlled and the quality can be improved when the key mat is manufactured.

It is sectional drawing of the keymat of a prior art. It is a side view of the keymat which concerns on embodiment of this invention. It is a side view of the keymat which concerns on other embodiment of this invention. 1 is a perspective view of an electronic device according to an embodiment of the present invention. It is sectional drawing which shows the mold open state of the metal mold | die which manufactures the keymat of this invention. It is sectional drawing which shows the mold closing state of the metal mold | die which manufactures the keymat of this invention. It is sectional drawing which shows the mold closing state of the metal mold | die which manufactures the keymat of this invention. It is sectional drawing which shows the mold open state of the metal mold | die which manufactures the keymat of this invention. It is sectional drawing which shows the process of adhere | attaching a key top on the key support part of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Keymat 31 Keytop 33 Key support part 331 Main body 333 Skirt part 335 Mounting part 337 Connection part 35 Adhesive 37 Textile 5 Keymat 51 Key top 53 Key support part 531 Main body 533 Skirt part 535 Mounting part 537 Connection part 55 Adhesive 57 Textile 7 Electronic device 71 Key 73 Display device 8 Mold 80 Fabric feed device 81 Female type 811 First insertion type 813 Second insertion type 83 First male type 85 Second male type 91 Textile 93 Light guide unit 95 Key support unit 97 key top

Claims (11)

In a key mat including a key top, a key support portion installed on the bottom surface of the key top, and a light guide portion installed on both ends of the key support portion,
It said key support portion is formed by extending a body, from the bottom of the body on both sides, and and the thickness is the body thinner least two skirt portions are projected perpendicularly to the bottom surface of the main body, and the lower side And a connection part that connects to a circuit board inside the electronic device when moving to
The keymat, wherein the light guide portion and the skirt portion are provided with a mesh-like woven fabric.   The key mat according to claim 1, wherein the fabric is integrally formed on the light guide portion and the skirt portion by an insert molding method.   The key mat according to claim 2, wherein the material forming the key support portion enters the mesh hole of the fabric, and the key support portion and the fabric are closely bonded.   The keymat according to claim 1, further comprising at least two mounting portions formed perpendicular to a bottom surface of the skirt portion and engaged with a cover of the electronic device when assembled.   5. The keymat according to claim 4, wherein a chamfer is formed at a connection portion between the main body and the skirt portion, and a connection portion between the skirt portion and the mounting portion.   2. The key mat according to claim 1, wherein the key top is made of a resin such as polycarbonate or polymethylmethacrylate.   The key mat according to claim 1, wherein the key support portion is made of silicone.   The key mat according to claim 1, wherein the key support portion is bonded to the bottom surface of the key top with an adhesive. And providing a female mold comprising a first insertion type and the second insertion type, a first male mold and a second male mold, the mold comprising,
Inserting a fabric between the female mold and the first male mold;
After the first insertion mold is inserted into the female mold, the first male mold and the female mold are brought close to each other to form a first cavity, and a resin is injected into the first cavity to guide it. Forming an optical part;
The second insertion mold is inserted into the female mold instead of the first insertion mold, the second male mold is inserted into the female mold instead of the first male mold, and then the female mold and the second mold are inserted. Forming a second cavity by approaching the male mold and injecting silicone into the second cavity to form a key support;
Adhering a key top onto the key support part that has been molded, and a method for manufacturing a key mat. In an electronic device to which a key mat is attached,
The key mat includes a key top, a key support portion installed on a bottom surface of the key top, and light guide portions installed on both ends of the key support portion,
It said key support portion is formed by extending a body, from the bottom of the body on both sides, and and the thickness is the body thinner least two skirt portions are projected perpendicularly to the bottom surface of the main body, and the lower side anda connecting portion connecting the interior of the circuit board of the electronic device when moved,
2. An electronic apparatus according to claim 1, wherein a mesh fabric is provided on the light guide portion and the skirt portion.   The electronic device according to claim 10, wherein the fabric is formed on the light guide portion and the skirt portion by an insert molding method.

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