JPH08111132A - Illumination-type keytop - Google Patents

Abstract

PURPOSE: To improve the manufacture yield by lessening the strain after forming and making a printing ink be taken well to a substrate. CONSTITUTION: After a LED chip 3 is mounted on a FPC 1, a thermosetting adhesive layer 6 is formed on either only the front side or both the front and back sides of the FPC 1. A resin part 5c is formed on either the front side of both the front and the back sides by injection molding. As another method, without forming the adhesive layer 6, molding resin flow holes are formed in the FPC 1 and then resin injection molding is carried out while sandwiching the front and back sides of the FPC 1 with the resin. In any case, ABS resin or phenolic resin to which a printing ink can be taken well and which has no adhesive property, excellent formability, and is hardly strained after molding may be used.

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 used for a panel switch or the like, and more particularly to improvement of manufacturing yield.

[0002]

2. Description of the Related Art Illuminated key tops 5 used for a conventional panel switch or the like are, as shown in FIG. 5, a flexible wiring board (FPC) 1 made of non-adhesive polyimide resin or the like. Since the structure is such that the resin portion 5c is molded on the front surface and the back surface by injection molding, it is necessary to use an adhesive material such as an epoxy resin for the molding resin. However, the epoxy resin has poor moldability, and when the characters and symbols are printed on the surface as well as distortion occurs in the molded product, there is a drawback that the ink adhesion is bad and the yield of the illuminated key tops is generally poor. .

The present invention is intended to solve these conventional drawbacks, reduce distortion after molding, improve ink adhesion, and improve the manufacturing yield.

[0004]

[Means for Solving the Problems]

(1) An illuminated key top according to claim 1, wherein an LED chip, an FPC on which the LED chip is mounted, and an FPC thereof are provided.
The thermosetting adhesive layer is attached to the front surface or the front surface and the back surface, and the resin portion injection-molded on the front surface or the front surface and the back surface of the FPC to which the adhesive layer is attached.

(2) The illuminated key top according to claim 2 is
LED chip and FPC mounted with the LED chip
And the molding resin flow hole formed in the FPC and the F
It is composed of a resin portion injection-molded so as to sandwich the PC from the back surface. (3) In the invention of claim 3, in the above (1) or (2)
In, the resin portion is formed of ABS resin or phenol resin.

(4) In the invention of claim 4, in the above (1)
Alternatively, in (2), the FPC is formed of a polyimide resin. (5) In the invention of claim 5, in the above (1) or (2)
In, the plurality of resin parts respectively encapsulating the LED chips are connected in a chain by the common FPC.

According to the first aspect of the invention, the molding resin is pressed against the FPC by the molding pressure at the time of injection molding and adheres thereto, and the thermosetting adhesive layer is formed by the heat of the resin melted in the liquid state at the time of injection molding. After softening, it is cooled and hardened, and the molded resin and FPC are fixed. Therefore, the production yield of key tops can be improved by using a material such as ABS resin or phenol resin, which has good adhesiveness as a molding resin, has good moldability, has little distortion after molding, and has good printing ink adhesion. Can be improved.

According to the second aspect of the present invention, the molding resin is pressed against the FPC by the molding pressure at the time of the injection molding and adheres to the FPC, and the resin portions molded on the front and back of the FPC are connected through the molding resin flow hole to form The structure will be fixed to. Therefore, it is possible to improve the manufacturing yield of the key tops by using an ABS resin, a phenol resin, or the like, which has no adhesiveness, but has good moldability and has good printing ink.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 are views relating to the illuminated key top according to claim 1, and parts corresponding to those in FIG. 5 are designated by the same reference numerals. 1A shows a resin key top 5a fixed to one surface of an FPC 1, and FIG. 1B shows an FPC 1.
The key tops 5a and 5b are fixed on both surfaces of the No. 1. 3 is an LED chip. Reference numeral 1 is an FPC having a function of providing a wiring for supplying a current to the LED chip 3 and connecting a plurality of key tops. The key tops 5 (5a, 5b) are formed and fixed on the FPC 1 by injection molding.

Reference numeral 6 denotes a thermosetting adhesive layer, which is softened by heat during injection molding and then cooled and hardened to bond and fix the key tops 5a and 5b to the FPC 1. The adhesive layer 6 may be fluid-like or sheet-like, and if it is fluid-like, FP
If it is formed by printing and coating on C1 and drying, and if it is in the form of a sheet, it is pasted on the FPC1 in a predetermined shape. 2a and 2b are lands provided on the FPC 1. Reference numeral 4 is a metal wire for connecting the LED chip 3 to the land 2b. FIG. 1C is a plan view of the FPC 1.
A thermosetting adhesive layer 6 is formed on the surface in a predetermined shape.

FIG. 2 is a diagram showing a manufacturing process of the illuminated key top of FIG. 1A. First, the thermosetting adhesive layer 6 is formed on the FPC 1. Next, the LED chip 3 is mounted and connected to the land 2b by the metal wire 4. Next, the FPC 1 manufactured in the above process is inserted into the injection molding die 7. FIG. 2C shows a state where the mold is clamped, and the upper mold 7
The FPC 1 is fixed in the mold 7 by tightening the a and the lower mold 7b together.

In this state, the molding resin which is heated and becomes liquid is injected from the resin injection gate 8 provided in the upper mold 7a. When the resin is sufficiently filled in the mold, the supply of the resin is stopped, and then the resin in the mold is cooled and solidified to form the key top 5a having a predetermined shape. In this series of molding processes, the adhesive layer 6 is softened by the heat of the injected resin, and when the resin is cooled after molding, it is simultaneously cooled and hardened to bond the resin portion 5c to the FPC 1. Illuminated key top 5
After a is cooled sufficiently, it is taken out from the mold 7. After that, characters, symbols, etc. are printed on the surface of the key top.

3 and 4 show an embodiment of the invention according to claim 2,
Portions corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description will be omitted. Reference numeral 9 denotes a molding resin flow hole provided in the FPC 1, which is a resin passage hole for pouring the resin into the other side when the molding resin is injected from one side of the FPC 1 by injection molding, and The key tops 5a and 5b formed on the front and back of the FPC1 are connected to each other to form the FPC1.
It is a hole for fixing to. The flow hole 9 may be removed at the same time when the outer shape of the FPC 1 is removed by a press or the like.

FIG. 4 is a diagram showing a manufacturing process of the illuminated key top 5 of the second aspect. First, the LED chip 3 is mounted on the FPC 1 provided with the resin flow hole 9 in advance, and is connected to the land 2b on the FPC 1 by the metal wire 4. Next, the FPC 1 manufactured in the above process is inserted into the injection molding die 7, and the upper die 7a and the lower die 7b are fastened together.

In this state, the molding resin which is heated and becomes liquid is injected from the gate 8 into which the resin provided in the lower mold 7b is injected. The liquid resin injected flows in as shown by the arrow in the figure, and at that time, the resin flow hole 9 provided in the wiring board 2
It flows into the upper mold 7a side. When the resin is sufficiently filled in the mold, the supply of the resin is stopped, and then the resin in the mold is cooled and solidified into a predetermined shape. The illuminated key top 5 can be obtained by taking out from the mold after sufficiently cooling. After that, characters, symbols and the like are printed on the surface of the key top 5.

The FPC 1 shown in FIGS. 1 and 4 is made of a non-adhesive polyimide resin or the like as in the conventional case. As described above, the resin portion 5c is made of an ABS resin, a phenol resin, or the like, which does not have adhesiveness but has good moldability and has good printing ink.

[0017]

According to the invention of claim 1, since the thermosetting adhesive layer 6 is provided on the FPC 1 and the resin is injection-molded thereon, the adhesive layer 6 is formed of the resin at the time of molding. The resin portion 5c and the FPC 1 are joined by being softened by heat and then cooled and hardened. In the invention of claim 2, FP
Through the molding resin flow hole 9 provided in C1, the resin portions 5c on both surfaces of the FPC 1 are integrally connected with the FPC 1 interposed therebetween. Therefore, in either case, the resin portion 5c has no adhesiveness,
It is possible to use a material such as an ABS resin or a phenolic resin which has good moldability, has little distortion after molding, and has good printing ink adhesion. As a result, the manufacturing yield of key tops can be significantly improved over the conventional one.

Further, since the ABS resin and the phenol resin are cheaper than the conventional epoxy resin, the key top can be made economical.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the invention of claim 1, which is A and B;
Is a longitudinal sectional view of an illuminated key top formed on one side or both sides of the FPC 1, and C is a plan view of the FPC 1 of A and B, respectively.

FIG. 2 is a cross-sectional view showing a manufacturing process of the illuminated key top of FIG. 1A.

3A and 3B are views showing an embodiment of the invention of claim 2, where A is a longitudinal sectional view and B is a plan view of the FPC 1 of A;

FIG. 4 is a cross-sectional view showing a manufacturing process of the illuminated key top of FIG.

FIG. 5 is a vertical sectional view of a conventional illuminated key top.

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Claims (5)

[Claims] 1. An LED chip, an FPC having the LED chip mounted on the front surface, a thermosetting adhesive layer attached to the front surface or the front surface and the back surface of the FPC, and the adhesive layer attached thereto. Illuminated key top consisting of an injection-molded resin portion on the front surface or front and back surfaces of the FPC. 2. An illumination system comprising an LED chip, an FPC on which the LED chip is mounted, a molding resin flow hole formed in the FPC, and a resin portion injection-molded so as to sandwich the FPC from the front and back. Key top. 3. The illuminated keytop according to claim 1, wherein the resin portion is made of ABS resin or phenol resin. 4. The FPC according to claim 1 or 2.
Illuminated key top characterized in that is made of polyimide resin. 5. The LED according to claim 1 or 2,
An illuminated keytop, wherein a plurality of the resin parts enclosing the chips are connected in a chain by the common FPC.