JPH0611237U - Illuminated key tops - Google Patents

Abstract

(57) [Abstract] [Purpose] High productivity, easy repair and replacement, and prevention of defects in the illumination circuit when installing the key top.
Also, to provide an illuminated key top capable of high brightness illumination. [Structure] The chip LED 1 is mounted on a flexible printed board 2 and soldered to a copper foil pattern 7. The key tops 4 are joined to the flexible printed circuit board 2 by thermal crimping at thermal crimping portions 6. A spherical light diffusing portion 5 is formed on the surface of the key top 4 facing the chip LED 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an illuminated key top, and more particularly to an illuminated key top in a panel switch.

[0002]

[Prior art]

 As shown in FIG. 5, a conventional illuminated type key top 51 for panel switch is integrally molded by injection molding so as to cover a bare chip LED 53 mounted on a flexible printed circuit board 52 which also serves as a key top hinge portion. Here, the bare LED 53 is connected to the copper foil pattern 55 on the flexible printed circuit board 52 by a wire connecting wire 54 by wire bonding.

[0003]

[Problems to be solved by the device]

 However, conventional illuminated keytops have a structure in which bare chip LEDs are mounted on a flexible printed circuit board and bare chip LEDs are connected by wire bonding. Therefore, when molding the keytop by injection molding, the injection pressure There is a problem that the connecting wire is easily detached and the bare chip LED is easily peeled off due to the force and the injection temperature. Further, there is a problem in that it is practically impossible because the key top and the bare chip LED are integrated even if an attempt is made to repair the malfunction. Further, in order to uniformly diffuse the light from the bare chip LED over the entire key top, a method of mixing a diffusion material into the molding material is usually adopted, but a large amount of the diffusion material was mixed in order to improve the diffusion effect. In this case, there is also a problem that the emission brightness is lowered.

The present invention enables easy and easy repair and replacement, prevents the occurrence of defects such as damage to the illumination circuit when attaching the keytop, and enables illumination with higher brightness. To provide key tops.

[0005]

[Means for Solving the Problems]

 According to the present invention, in an illuminated keytop fixed to the printed circuit board so as to cover the chip LED mounted on the printed circuit board, a light diffusing unit for diffusing light from the chip LED is provided. Illuminated key tops featuring.

[0006]

[Action]

 The light diffusion portion defines the existence space of the chip LED and the key top and the chip LED do not come into direct contact with each other, so that it is possible to prevent the occurrence of defects during manufacturing. Further, since the key top and the chip LED are not integrated, only the key top can be removed, and the repair can be facilitated. Furthermore, the light emitted from the LED can be diffused uniformly over the entire key top without mixing a diffusing agent, and high-luminance illumination can be realized.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an illuminated key top according to an embodiment of the present invention. The chip LED 11, which is a light emitting element, is mounted on the flexible printed board 12 and is connected to the copper foil pattern 13 for wiring formed on the flexible printed board 12 by soldering. A current is supplied to the chip LED 11 via the copper foil pattern 13.

The key top 14 is made in advance by injection molding or the like. The surface of the key top 14 facing the chip LED 11 is formed in a spherical shape (concave spherical shape) as the light diffusion portion 15. This is for uniformly diffusing the light emitted from the chip LED 11 (indicated by the arrow R in the figure) over the entire surface of the keytop 14, and depending on the shape of the keytop 14 and the degree of diffusion, Preformed into shape. The key top 14 is fixed by a heat caulking method by inserting a protrusion 17 into an insertion hole 16 formed in the flexible printed board 12 in advance.

For reference, FIG. 2 shows the flexible printed circuit board 12 on which the chip LEDs 11 are mounted before the key top 14 is attached. Four key portions 21a, 21b, 21c, and 21d are formed on the flexible printed circuit board 12, and the key top hinge portions 22a, 22b, 22c, and 22d respectively provide the vertical direction (see the figure). It is possible to move in both directions. Further, a copper foil pattern 13 is formed on the surface of the flexible printed board 12, and its terminal portion 23 is connected to an external LED drive circuit (not shown). The external LED drive circuit can freely illuminate the chip LEDs 11 mounted on the flexible printed circuit board 12 individually or collectively illuminate all the chip LEDs 11 collectively.

A plurality of chip LEDs 11, for example, two chip LEDs 11 may be mounted on the same key portion (key portions 21a and 21b in the figure). This allows the emission brightness of each key section to be freely selected. Then, the emission colors of the plurality of chips LED11 are appropriately selected from, for example, red, yellow, green, amber, etc., and the individual LEDs of the respective chips are individually illuminated or combined in the same key portion, so that multiple colors in the same key portion can be obtained. It can also emit light.

FIG. 3 shows a state in which the illuminated key top 14 is attached to the flexible printed circuit board 12 shown in FIG. 2 and housed in the housing. The terminal portion 23 of the flexible printed board 12 is connected to the terminal portion 32 provided on the logic board 31 including the LED drive circuit. A switch 33 is formed on the logic board 31, and when the key top 14 is pushed down, a switch operation is performed, and a chip LED in the pushed key top emits light.

Next, a process of thermally crimping the illuminated key top 14 of this embodiment will be described with reference to FIG. As shown in FIG. 4A, the chip LED 1 is connected and fixed to the copper foil pattern 13 on the flexible printed board 12 by soldering. An insertion hole 16 is formed at a predetermined position on the flexible printed board 12.

The key top 14 is previously formed by injection molding, and at this time, the light diffusion portion 15 and the thermal caulking projection 17 are also formed. Then, when performing thermal crimping, as shown in FIG. 4B, the thermal crimping protrusions 17 are inserted into the protrusion insertion holes 16 of the flexible printed circuit board 12. Next, as shown in FIG. 4 (c), the heated caulking die 41 is pressed against the thermal caulking projections 17 to melt and heat caulking, and the key top 14 is fixed to the flexible printed board 12. It

[0014]

[Effect of device]

 According to the present invention, since the key top is provided with the light diffusing portion, the key top and the chip LED are not integrated, and only the key top can be removed, so that repair and replacement can be easily and easily performed. In addition, no defects such as damage to the chip LED and wiring occur when the key top is attached. Furthermore, the function of the light diffusing section enables high-luminance illumination.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an illuminated key top according to an embodiment of the present invention.

FIG. 2 is a plan view of a flexible printed board.

FIG. 3 is a transverse cross-sectional view showing a state where the illuminated key top of FIG. 1 is incorporated in a housing.

FIG. 4 is a process diagram for explaining a process of the thermal crimping method for the illuminated key top of FIG.

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

[Explanation of symbols]

11 Chip LED 12 Flexible Printed Circuit Board 13 Copper Foil Pattern 14 Key Top 15 Light Diffusing Part 16 Insertion Hole 17 Protrusions 21a, 21b, 21c, 21d Key Part 22a, 22b, 22c, 22d Key Top Hinge Part 23 Terminal Part 31 Logic Board 32 Terminal part 33 Switch 41 Thermal caulking die 51 Key top 52 Flexible printed circuit board 53 Bare chip LED 54 Connecting wire

Claims (2)

[Scope of utility model registration request] 1. An illuminated key top fixed to a printed circuit board so as to cover the chip LED mounted on the printed circuit board, comprising a light diffusion section for diffusing light from the chip LED. Illuminated key top. 2. The illuminated keytop according to claim 1, wherein the light diffusion portion has a concave spherical shape.