JPH09129077A - Lighted type key top and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently provide a lighted type key top free from damage by integrally injection-molding a light transmitting thermoplastic synthetic resin to a flexible wiring board having a chip LED loaded thereon. SOLUTION: (1) A bare chip LED 1 is connected and fixed to the part for forming a key top 3 of a flexible wiring board 2, and a light transmitting thermoplastic synthetic resin is integrally injection-molded to form a sealed molding part 6. (2) An upper metal mold 10a having a key top female die 3' curved and formed thereon is prepared. (3) A lower metal mold 10b having a plurality of fixed part female dies 7' for forming key top fixing parts 7 for integrating the key top 3 to the wiring board 2, which are formed on the periphery, a gate 9a formed on either one of the fixed part female dies 7' so as to communicate with it, and a pressing part female die 8' extended from either one of the fixed part female dies 7' so as to communicate with it is prepared. (4) The sealed molding part 6 is positioned in the position corresponding to the key top female die 3' and the fixed part female dies 7', and the light transmitting thermoplastic synthetic resin is integrally injection-molded to form the key top 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminated key top and a method for manufacturing the same, and more particularly to a key top formed by integrally molding a transparent wiring synthetic resin on a flexible wiring board on which a chip LED is mounted. The present invention relates to an illuminated key top and a manufacturing method thereof.

[0002]

2. Description of the Related Art A conventional example will be described with reference to FIG. Reference numeral 1 is a bare chip LED. The bare chip LED 1 is electromechanically coupled and fixed to the flexible wiring board 2. That is, the bare chip LED 1 is connected and fixed to the place where the key top 3 of the flexible wiring board 2 is to be formed. The bare chip LED 1 is electrically and mechanically connected and fixed to the wiring 5a formed on the surface of the flexible wiring board 2 and electrically connected to the other wiring 5b formed on the surface of the flexible wiring board 2 via the bonding wire 4. Connected to. Reference numeral 6 denotes a sealing molding portion, which is configured by applying an epoxy resin or other liquid thermosetting synthetic resin. This liquid thermosetting synthetic resin is cured to leave bare chip LE.
D1 is the bonding wire 4, the wiring 5a and the wiring 5
It is embedded in the encapsulation molding portion 6 made of a thermosetting synthetic resin that is hardened including b.

The upper die 10a is formed with a keytop female die 3'filled with a synthetic resin forming the upper half of the keytop 3. The lower die 10b is provided with a keytop female die 3'filled with a synthetic resin forming the lower half of the keytop 3. In the central portion of the key top female die 3'of the lower die 10b, a pressing portion female die 8'filled with a synthetic resin forming the switch pressing portion 8 is formed deeper. Reference numeral 9a is a gate formed in the lower die 10b, which communicates with the keytop female die 3 '. Although only one upper die 10a and one lower die 10b are shown in FIG. 5, the actual die is similar to the place where the key top 3 is to be formed. Each is formed.

[0004]

Here, the flexible wiring board 2 is positioned so that the key top 3 of the flexible wiring board 2 is integrally molded in the female mold 3'of the upper mold 10a and the lower mold 10b. The plate 2 is sandwiched between molds, and the female mold 3'is filled with the translucent synthetic resin melted through the gate 9a. Since the portion of the flexible wiring board 2 where the above-mentioned key tops 3 are to be integrally molded is suspended in the female mold 3 ', the molten translucent synthetic resin is applied to the flexible wiring board 2 as shown by the arrow. It will be distributed to both the upper side and the lower side. Flexible wiring board 2
Is in such a state, the upper mold 10a and the lower mold 10b
When the molten translucent synthetic resin is filled in the mold, the conditions for the upper side and the lower side of the flexible wiring board 2 are not equal, so the filling pressure of the synthetic resin is applied to the flexible wiring board 2 unevenly. The flexible wiring board 2 may be deformed due to the uneven filling pressure, which may damage the bare chip LED 1 and generate an illuminated keytop in which the LED 1 does not emit light.

Before molding the key top 3, the bare chip LED is previously sealed and hardened with an epoxy resin or other liquid thermosetting synthetic resin as described above, and this hardening takes 20 to 24 hours. In total, the time required to manufacture the illuminated key top is increased. The present invention provides an illuminated key top and a method for manufacturing the same, in which the problems described above are solved.

[0006]

[Means for Solving the Problems] An illuminated key top is constructed by integrally molding a transparent wiring synthetic resin on a flexible wiring board 2 in which a bare chip LED 1 is electromechanically coupled and fixed to form a key top. did. Then, the bare chip LED 1 constitutes an illuminated key top which is embedded in a translucent thermoplastic synthetic resin having a large fluidity in a molten state.

Further, the key top 3 penetrates the flexible wiring board 2 at a plurality of positions on the peripheral portion thereof and is integrally molded with the flexible wiring board 2, and the lower surface of the flexible wiring board 2 is exposed to form an illuminated key top. did. Here, the bare chip LED 1 is connected and fixed to the place where the key top 3 of the flexible wiring board 2 is to be formed, and the transparent molding synthetic resin is integrally injection-molded at this place to form the sealing molding part 6. Then, the upper mold 10a in which the key top female mold 3'filled with the synthetic resin corresponding to the key top 3 is curved is formed, and the key top 3 is formed.
A plurality of fixing part female dies 7 ′ forming a key top fixing part 7 for integrally integrating the flexible wiring board 2 and the flexible wiring board 2 are formed in the peripheral portion, and any one of the fixing part female dies 7 ′ has a gate. 9a
A lower die 10 in which a pressing portion female die 8'formed by stretching and communicating from any one of the fixed portion female die 7'is formed.
b, the sealing molding portion 6 is positioned at a position corresponding to the key top female die 3'of the upper die 10a and the fixed portion female die 7'of the lower die 10b, and the translucent thermoplastic synthetic resin is used. A method for manufacturing an illuminated key top in which the key top 3 is formed by integrally molding

The bare chip LED 1 is connected and fixed where the key top 3 is to be formed, and a filling hole 17 is formed near the bare chip LED 1 so as to face the gate 9b of the lower mold 20b. Top fixing part 7
The upper mold 20 in which the flexible molded wiring board 2 having the through holes 18 corresponding to the positions where the molds are to be formed is formed, and the sealing molding portion female mold 6 ′ forming the sealing molding portion 6 is curvedly formed.
a lower mold 20b that constitutes a and has a gate 9b corresponding to the female mold 6'of the sealing molding part of the upper mold 20a.
And the bare chip LED 1 that is connected to and fixed to the flexible wiring board 2 is formed into the female mold 6'of the sealing molding portion of the upper mold 20a.
The flexible wiring board 2 is positioned inside the upper mold 20.
It is clamped between a and the lower die 20b, and in this state,
From the gate 9b of the lower mold 20b to the flexible wiring board 2
The molten translucent thermoplastic synthetic resin is filled into the mold of the upper mold 20a through the filling hole 17 of the bare chip LED1.
An upper die for forming a sealing molding portion 6 embedded in a light-transmissive thermoplastic synthetic resin in which is solidified, and a key top female die 3'filled with a synthetic resin corresponding to the key top 3 is curvedly formed. A key top fixing portion 7 that configures 10a and integrates the key top 3 and the flexible wiring board 2 with each other.
A plurality of fixed part female dies 7'that form a plurality of fixed part female dies 7'are formed in the peripheral portion, and a gate 9a is formed to communicate with any one of the fixed part female dies 7 '. A lower die 10b is formed in which a pressing portion female die 8'which extends and communicates from one piece is formed, and a sealing molding portion 6 is fixed between the key top female die 3'of the upper die 10a and the lower die 10b. The flexible wiring board 2 is sandwiched between these molds by positioning the flexible wiring board 2 at a position corresponding to the female mold 7 ', and in this state, the gate 9 of the lower mold 10b is held.
female part 7'of the fixed part formed to communicate with the gate 9a from a
A transparent light-transmissive thermoplastic synthetic resin corresponding to the key top 3 is filled with the light-transmissive thermoplastic synthetic resin melted in the key-top female mold 3a of the upper mold 10a via A method for manufacturing an illuminated key top that is embedded in the structure is constructed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the examples of FIGS. FIG. 1 is a diagram for explaining the construction of a key top by injection molding according to the present invention. FIG. 2 is a view for explaining a key top constructed according to the present invention, and FIG. 2 (a) is a line a in FIG. 2 (b).
It is a figure which shows the place which looked at the cross section in -a 'in the arrow direction, and FIG. FIG. 3 is a view for explaining that a bare chip LED is previously sealed with a translucent thermoplastic synthetic resin.

Referring to FIG. 3, the upper die 20a is formed with a curved molding die 6'for forming a molding die 6 for forming the molding die 6. Then, the lower mold 20b has an upper mold 20a.
A gate 9b is formed corresponding to the female mold 6'of the sealing molding part. Although FIG. 3 shows only one female mold 6 ′ for the sealing molding portion in which the upper mold 20a is filled with the synthetic resin, the key top 3 is actually formed on the upper mold 20a. Similar female molding dies 6 ′ for sealing molding are formed corresponding to the respective places. Similarly, in the lower die 20b, the gates 9b are formed corresponding to the places where the key tops 3 are to be formed.

The bare chip LED 1 is connected and fixed to the place where the key top 3 of the flexible wiring board 2 is to be formed. That is, the wiring 5a formed on the surface of the flexible wiring board 2 is electrically and mechanically connected and fixed, and the other wiring 5b formed on the surface of the flexible wiring board 2 is electrically connected via the bonding wire 4. To be done. A filling hole 17 is formed near the bare chip LED 1 of the flexible wiring board 2 so as to face the gate 9b of the lower mold 20b. And the flexible wiring board 2
A through hole 18 is formed corresponding to a place where the key top fixing portion 7 described later will be formed.

Here, the bare chip LED 1 which is connected and fixed to the flexible wiring board 2 is positioned in the female mold 6'of the sealing molding portion of the upper mold 20a and the lower mold 20b, and the flexible wiring board 2 is fixed to these molds. Hold it in between. In this state, through the filling hole 17 of the flexible wiring board 2 from the gate 9b of the lower mold 20b, the mold of the upper mold 20a is filled with the translucent thermoplastic synthetic resin melted in the direction of the arrow. . The bare chip LED 1 including the bonding wire 4, the wiring 5a, and the wiring 5b is embedded in the melted translucent thermoplastic synthetic resin. After the light-transmitting thermoplastic synthetic resin filled in the mold is cooled, the upper mold 20a and the lower mold 20b are removed to be fixedly connected to the flexible wiring board 2 and solidified. The bare chip LED 1 is embedded in the resin.

The bare chip LED 1 itself has a very small mechanical strength, and the bonding wire 4 for connecting the bare chip LED 1 and the wiring 5b has a very small mechanical strength and is easy to cut. When a low light-transmissive thermoplastic synthetic resin is flow-filled by a strong pressure, they are damaged. For these reasons, the translucent thermoplastic synthetic resin is required to be a material having good fluidity in the molten state, and polystyrene that meets this requirement can be used.

Next, referring to FIGS. 1 and 2, the bare chip LED 1 embedded in the solidified transparent thermoplastic synthetic resin is connected and fixed to the flexible wiring board 2 as described above. A method of forming a key top by integrally injection molding synthetic resin will be described. Upper mold 1
A key top female die 3'filled with a synthetic resin corresponding to the key top 3 is curvedly formed at 0a. Since the key top 3 has an outer shape of a quadrangular prism, the upper die 10a
The key top female die 3'is formed as a complementary female die corresponding to the outer shape of the square pole. In FIG. 1, only one key top female die 3'for forming the key top 3 on the upper die 10a is shown, but the key top 3 is actually formed on the upper die 10a. Similar key top female molds 3'are formed corresponding to the respective places.

At the four corners of the peripheral edge of the lower die 10b, there are formed fixing portion female dies 7'for forming keytop fixing portions 7 for integrating the keytop 3 and the flexible wiring board 2 with each other. There is. Further, the gate 9a is formed in communication with any one of the fixed portion female dies 7'of the lower die 10b.
In the lower die 10b, any one of the fixing portion female dies 7 '
A pressing portion female mold 8 ′ is formed which extends and communicates from the individual to where the switch pressing portion 8 should be formed.
To form The fixed portion female die 7'of the pressing portion female die 8 '
Switch pressing part 8 as compared with the part that extends horizontally from
The part where is formed is slightly deeper. In the lower die 10b, four fixing portion female molds 7'that form the keytop fixing portion 7 are formed corresponding to where the keytops 3 are to be formed. As described above, the lower die 10b has the metal material forming the lower die 10b and the fixed portion female die 7'at four corners downward from the upper surface and at least one of the fixed portion female die 7 '. Although a pressing portion female mold 8'that extends and communicates with the switch pressing portion 8 to be formed is formed, the other region of the upper surface of the metal material blank remains flat.

Here, the bare chip LED 1 connected and fixed to the flexible wiring board 2 is positioned at a position corresponding to the key top female die 3'of the upper die 10a and the fixed portion female die 7'of the lower die 10b. The flexible wiring board 2 is sandwiched between these molds. Most of the flexible wiring board 2 is sandwiched by the upper mold 10a and the lower mold 10b, except that it faces the fixed part female mold 7'and the pressing part female 8 '. It contacts the upper surface of 10b and is thereby supported from below.

In this state, the arrow 9 is inserted into the key top female die 3'of the upper die 10a through the fixed portion female die 7'communicated from the gate 9a of the lower die 10b. The transparent thermoplastic synthetic resin melted in the direction is filled. The translucent thermoplastic synthetic resin melted in the key-top female mold 3'circulates in the direction of the arrow. Then, this flow reaches from the key top female die 3 ′ of the upper die 10 a to the fixed portion female die 7 ′ through the flow hole 18 and communicates with one of the fixed portion female dies 7 ′. The pressing portion female mold 8'which extends and communicates to the point where 8 should be formed is also reached. Due to such flow of the molten translucent thermoplastic synthetic resin, a downward pressure indicated by a short arrow is applied to the flexible wiring board 2.
However, even if such a downward pressure is applied, the flexible wiring board 2 is clamped by the upper die 10a and the lower die 10b as described above, and the fixed portion female die 7'and the pressing portion female die 7'are held. There is no risk of deformation because it is in contact with the upper surface of the lower mold 10b except that it faces the mold 8'and is supported upward from below by this.

In this way, the bare chip LED 1 including the bonding wire 4, the wiring 5a, and the wiring 5b is embedded in the molten light-transmitting thermoplastic synthetic resin. After the translucent thermoplastic synthetic resin filled in the mold is cooled, it is removed from the upper mold 10a and the lower mold 10b, so that the key top fixing portion 7 is attached to the flexible wiring board 2 as shown in FIG. The bare chip LED 1 is connected and fixed via the above, and is embedded in the solidified translucent thermoplastic synthetic resin corresponding to the key top 3.

The illuminated key top configured as described above looks as shown in FIG. 4 (a) when viewed from above and is shown in FIG. 4 (b) when viewed from the side. Looks like.

[0020]

As described above, according to the present invention, before molding the key top 3, the bare chip LED including the bonding wire 4, the wiring 5a and the wiring 5b has good fluidity in a molten state. Since it is embedded in the translucent thermoplastic synthetic resin, the translucent thermoplastic synthetic resin filled in the mold is cooled, and then the upper mold 20a and the lower mold 20b are removed so that Bare chip L embedded in a translucent thermoplastic synthetic resin solidified in
ED1 can be configured. As in the above-mentioned conventional example, it is necessary to seal with a thermosetting synthetic resin and cure it.
The time required to manufacture the illuminated key top does not become long as it takes 0 to 24 hours. When molding the key top 3, a downward pressure indicated by a short arrow is applied to the flexible wiring board 2 due to the circulation of the translucent thermoplastic synthetic resin.
However, even if such a downward pressure is applied, the flexible wiring board 2 is clamped by the upper die 10a and the lower die 10b as described above, and the fixed portion female die 7'and the pressing portion female die 7'are held. There is no risk of deformation because it is in contact with the upper surface of the lower mold 10b except that it faces the mold 8'and is supported upward from below by this. Therefore,
Even when the bare chip LED is embedded in a synthetic resin in advance for protection and the key top 3 is integrally molded with the synthetic resin, the bare chip LED including the bonding wire 4, the wiring 5a and the wiring 5b is not damaged. It is possible to efficiently manufacture an illuminated key top that has few and no damages thereon in a short time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a manufacturing method.

FIG. 2 is a diagram showing an example.

FIG. 3 is a diagram illustrating an intermediate step of the embodiment of the manufacturing method.

FIG. 4 is a diagram showing an appearance of an example.

FIG. 5 is a diagram illustrating a conventional example.

[Explanation of symbols]

 1 Bare Chip LED 2 Flexible Wiring Board 3 Key Top 3'Key Top Female 6 Encapsulation Molding Part 6'Encapsulation Molding Part Female 7 Key Top Fixing Part 7'Fixing Part Female 8 Switch Pressing Part 8'Pressing Part Female Type 9a gate 9b gate 17 filling hole 18 through hole 20a upper mold 20b lower mold

Claims (5)

[Claims] 1. An illuminated keytop comprising a flexible wiring board to which a bare chip LED is electromechanically coupled and fixed, and a transparent thermoplastic synthetic resin being integrally injection-molded to form a keytop. 2. The illuminated keytop according to claim 1, wherein the bare chip LED is embedded in a first translucent thermoplastic synthetic resin. 3. The illuminated keytop according to claim 1, wherein the keytop is formed integrally with the flexible wiring board by penetrating the flexible wiring board at a plurality of positions on the peripheral edge thereof. Illuminated key top characterized in that the lower surface of the flexible wiring board is exposed. 4. A bare chip LED is connected and fixed to a place where a key top of a flexible wiring board is to be formed, and a transparent thermoplastic synthetic resin is integrally injection-molded to form a sealing molding part. , A fixing that forms an upper mold in which a keytop female mold filled with a synthetic resin corresponding to the keytop is curvedly formed, and forms a keytop fixing portion that integrates the keytop and the flexible wiring board with each other. A plurality of part female molds are formed in the peripheral portion, and a gate is formed to communicate with any one of the fixed part female molds, and a pressing part female mold that extends and communicates from any one of the fixed part female molds is provided. Configure the formed lower mold, position the sealing molding part at a position corresponding to the key top female mold of the upper mold and the fixing part female mold of the lower mold, and set the translucent thermoplastic synthetic resin. Injection molded integrally to form a key top Method of manufacturing the illumination type key top, wherein Rukoto. 5. A bare chip LED is connected and fixed to a place where a key top is to be formed, and a bare chip LE is provided.
A flexible wiring board is formed in which a filling hole is formed near D in the vicinity of the gate of the lower mold, and a through hole is formed corresponding to where the keytop fixing portion 7 is to be formed. A lower mold having a gate is formed corresponding to the female mold of the upper molding die. Bare chip LED that is constructed and connected and fixed to a flexible wiring board
Is positioned in the female molding die of the upper mold, and the flexible wiring board is sandwiched between the upper and lower molds, and in this state, the flexible wiring board is moved from the gate of the lower mold to the flexible wiring board. Filling the molten translucent thermoplastic synthetic resin into the mold of the upper mold through the filling hole, to form a sealing molding part in a state where the bare chip LED is embedded in the solidified translucent thermoplastic synthetic resin, A fixing part that forms an upper mold in which a female part of the keytop filled with a synthetic resin corresponding to the keytop is curved and forms a keytop fixing part that mutually integrates the keytop and the flexible wiring board. A plurality of female molds are formed in the peripheral portion, a gate is formed to communicate with any one of the fixed part female molds, and a pressing part female mold is formed that extends and communicates with any one of the fixed part female molds. The lower mold that has been Fixing part of the key top female mold and the lower mold is positioned so as to sandwich the flexible wiring board between these molds, and in this state, the lower mold gate communicates with this gate. The melted translucent thermoplastic synthetic resin is filled into the key top female mold of the upper mold via the fixed part female mold, and the solid molded translucent thermoplastic synthetic equivalent to the key top is the sealing molding part. A method for manufacturing an illuminated key top, characterized in that it is embedded in a resin.