JP2004079338A - Light switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light switch having a good click touch by using an EL sheet. <P>SOLUTION: Fixed contacts 7a and 7b are provided on an upper surface of a switch board 7. A movable contact 8 of dome shape is provided above the switch board 7. The movable contact 8 is elastically deformed so as to contact with or separate from the fixed contact 7a. A fixed sheet 9 covering the movable contact 8 is connected to the switch board 7. The movable contact 8 is fixed between the fixed sheet 9 and the switch board 7. An EL sheet E is provided above the fixed sheet 9. The EL sheet E and the fixed sheet 9 are connected to each other via a both-side adhesive sheet 10. The both-side adhesive sheet 10 is provided with a through hole 10a such that a portion corresponding to the movable contact 8 does not bind with the movable contact 8. Thus, the both-side adhesive sheet 10 is adhered to the movable contact 8 at a peripheral portion thereof. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an illuminated switch for a mobile phone, a portable information terminal, an audio device, a home appliance, and the like, and more particularly to a switch illuminated by an EL sheet.
[0002]
[Prior art]
An illuminated switch using an EL sheet as a surface light emitter can illuminate the entire surface of the operation keytop, and is bright and has good visibility. As a prior art, there is Japanese Patent Application No. 2000-64023 previously proposed by the present applicant. As shown in FIG. 8, a dome-shaped movable contact (hereinafter referred to as “metal dome”) C is fixed by a fixing sheet D above a switch board B on which a fixed contact A is provided. B at a predetermined position. Above the fixing sheet D, a flexible EL sheet E is adhered by an adhesive member F such as a double-sided adhesive sheet. As shown in FIG. 9, the adhesive member F is formed so as to cover the entire surface of the metal dome C and adhere to the switch substrate B. As shown in FIG. 8, a key top G made of a transparent member is disposed above the EL sheet E. The key top G has a protrusion on the upper surface thereof protruded from a window hole of the outer case H so that the key top G can be pressed. The protrusion on the lower surface presses the vertex of the EL sheet E in contact with the vertex of the metal dome C. Shape.
[0003]
[Problems to be solved by the invention]
In this conventional illumination switch, the metal dome C is pressed and released by the key top G because the fixing sheet D, the adhesive member F such as a double-sided adhesive sheet, and the EL sheet E overlap on the metal dome C. There is a problem that it is difficult to obtain a good click feeling during the switch operation. That is, since the thickness of the EL sheet E is about 200 μm, the thickness of the double-sided adhesive sheet F is about 75 μm, and the thickness of the fixing sheet D is 50 μm, a total thickness of 325 μm covers the metal dome C. This is because the switch operation load is significantly increased when the switch operation is performed, and is significantly inferior to the click feeling obtained by the switch operation when the metal dome C is used alone.
[0004]
Therefore, the present invention provides an illuminated switch that can obtain a good click feeling even when illuminated by an EL sheet.
[0005]
[Means for Solving the Problems]
In the illuminated switch of the present invention, a fixed contact is provided on the switch board, and a dome-shaped movable contact that is brought into contact with and separated from the fixed contact by being elastically deformed is provided above the switch board. Above the movable contact, a fixing sheet that is joined to the movable contact and the switch board and fixes the movable contact between the movable contact and the switch board is provided. An EL sheet to be joined to the fixing sheet is provided on the upper side, and the EL sheet and the fixing sheet are adhered to the movable contact peripheral portion at a portion corresponding to the movable contact as a non-adhesive portion. It is characterized by having. With this configuration, when the switch operation is performed, the switch operation load is reduced, and the switch operation can be performed with a good click feeling corresponding to the case of a single metal dome.
[0006]
Further, the EL sheet and the fixing sheet are bonded via a double-sided adhesive sheet, and the double-sided adhesive sheet has a through hole that forms the non-adhesive portion at a portion corresponding to the movable contact. Is preferred.
[0007]
Further, it is preferable that a plurality of the movable contacts are provided, and the through-holes are respectively formed in portions corresponding to the movable contacts.
[0008]
Furthermore, it is preferable that the double-sided adhesive sheet is formed with a slit communicating the adjacent through-holes.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0010]
FIG. 1 shows an EL sheet E used in the present invention. That is, the EL sheet E is formed by sequentially laminating the transparent electrode layer 2, the light emitting layer 3, the insulating layer 4, the back electrode layer 5, and the protective layer 6 on the transparent substrate 1 from the upper layer. It is. The transparent substrate 1 is a film made of polyethylene terephthalate (hereinafter referred to as “PET”), on which indium-tin oxide (hereinafter referred to as “ITO”) constituting the transparent electrode layer 2 is deposited. I have. In this example, the thickness is 75 μm.
[0011]
The light emitting layer 3 is formed by printing light emitting ink on the upper surface of the transparent electrode layer 2. As a luminous body constituting the luminous ink, zinc sulfide (ZnS) doped with Cu is used. As the luminescent ink, a luminescent ink is prepared by using the luminescent material and a fluororesin binder obtained by dissolving a copolymer of vinylidene fluoride and propylene hexafluoride in methyl ethyl ketone as a solvent, and mixing and stirring these. This luminescent ink is printed on the upper surface of the transparent electrode layer 2 by a method such as a screen printing method, and then heated and dried to form the luminescent layer 3.
[0012]
The insulating layer 4 is formed on the light emitting layer 3. The ink for forming the insulating layer 4 is produced by mixing a high dielectric substance made of barium titanate (BaTiO ₃ ) with the above-mentioned fluororesin binder and stirring the mixture. Using this ink, the insulating layer 4 is formed in the same manner as in the formation of the light emitting layer 3.
[0013]
The back electrode layer 5 is formed by printing carbon ink on the upper surface of the insulating layer 4, heating and drying. The carbon ink is formed by mixing carbon powder, which is a conductor, with a polyester resin as a binder. The back electrode layer 5 may be composed of carbon powder, silver powder, copper powder, and polyester as a binder.
[0014]
The protective layer 6 is formed by printing an electrically insulating material such as polyester on the back electrode layer 5 by a screen printing method or the like in the same manner as described above, and then heating and drying to form the protective layer 6. Polyimide, polyvinyl chloride, or the like may be used as the electrically insulating material. Thus, the flexible EL sheet E is formed.
[0015]
FIG. 2 shows the configuration of the switch. The switch substrate 7 is located at the lowermost part of the switch, and a pair of fixed contacts 7a and 7b are provided on the upper surface of the switch substrate 7. The fixed contact 7a is located at the center, and the fixed contact 7b has a ring shape centered on the fixed contact 7a. Above the fixed contacts 7a and 7b, a dome-shaped movable contact 8 is provided. The movable contact 8 is, for example, a metal dome formed of a metal material having conductivity, and the peripheral end thereof is fixed to the switch substrate 7 by being brought into contact with a ring-shaped fixed contact 7b. That is, the fixing sheet 9 is bonded to the metal dome 8 and the switch substrate 7 and fixes the metal dome 8 between the metal dome 8 and the switch substrate 7. The fixing sheet 9 is, for example, a PET film with an adhesive provided with an adhesive on the lower surface, has a thickness of about 50 μm, and covers the entire surface of the metal dome 8 and is adhered to the upper surface of the switch substrate 7. It is.
[0016]
The metal dome 8 can be elastically deformed. When the top of the metal dome 8 is pressed downward by a human finger, the metal dome 8 is elastically deformed and dented. When the finger is released, the metal dome 8 returns to its original shape. The metal dome 8 has an appropriate click feeling so that it is deformed with a moderate force when it is pressed and dented and returns from the elastic deformation state to the original shape. When the metal dome 8 is elastically deformed and dented, it comes into contact with the fixed contact 7a and is electrically connected to the fixed contact 7b.
[0017]
The EL sheet E is adhered to the fixing sheet 9 by an adhesive member 10 such as a double-sided adhesive sheet. The shape of the double-sided adhesive sheet 10 is as shown in FIG. 3, and a portion corresponding to the metal dome 8 is adhered to the periphery of the metal dome 8 as a non-adhesive portion. It has a shape in which a hole 10a is formed. The diameter of the through hole 10a is set larger than the diameter of the metal dome 8 so that the metal dome 8 does not come into contact with the double-sided adhesive sheet 10 even when the metal dome 8 is elastically deformed. FIG. 4 shows a state in which the EL sheet E is bonded using the double-sided adhesive sheet 10. Only the fixing sheet 9 and the EL sheet E are located on the metal dome 8. The thickness of the EL sheet E is about 200 μm, and the thickness of the fixing sheet 9 is 50 μm. Only a total thickness of 250 μm is located on the metal dome 8, which is sufficiently thinner than the conventional 325 μm. is there.
[0018]
FIG. 5 shows a state in which a switch operation member is provided above the EL sheet E, and a key top 11 made of a transparent member is provided. The key top 11 has a projection 11a on the upper surface thereof protruding from a window hole 12a of the outer case 12 so that the key top 11 can be pressed. The projection 11b on the lower surface of the key top 11 presses the vertex of the metal dome 8 via the EL sheet E. Shape.
[0019]
The operation of such an illuminated switch is such that the metal dome 8 is deformed by applying a load to the apex of the metal dome 8 via the key top 11, the pair of fixed contacts 7a and 7b are short-circuited, and the switch is closed. When the load is released, the metal dome 8 is elastically restored, and the short-circuit between the pair of fixed contacts 7a and 7b is eliminated, and the switch is opened. Since only the EL sheet E and the fixing sheet 9 are covered on the metal dome 8, a remarkable increase in load and a decrease in click feeling are not caused.
[0020]
FIG. 6 shows another shape of the adhesive member. This double-sided adhesive sheet 20 is an adhesive member used when a plurality of metal domes constituting a switch are provided on the same switch substrate and one EL sheet E is adhered to constitute a plurality of illuminated switches. It is. Therefore, in order to make each corresponding portion with the plurality of metal domes 8a to 8f a non-adhesive portion, this double-sided adhesive sheet 20 has the same position as that described with reference to FIG. Each through hole 20a to 20f is formed. Therefore, if the double-sided adhesive sheet 20 is positioned and bonded on the fixing sheet 9 so that the through holes 20a to 20f correspond to the metal domes 8a to 8f, and the EL sheet E is bonded thereon. (1) A plurality of illuminated switches can be easily formed on one switch substrate.
[0021]
FIG. 7 shows another shape of the adhesive member. This double-sided adhesive sheet 30 is an adhesive member for easily forming a plurality of illuminated switches on one switch substrate, as in the previous example, and corresponds to each of the plurality of metal domes 8a to 8f. In order to make a non-adhesive portion, through holes 30a to 30f similar to those described with reference to FIG. 3 are formed at respective positions facing respective corresponding portions. Further, in this example, slits 31a to 31e communicating with adjacent through holes are formed so that all the through holes 30a to 30f communicate with each other. Therefore, if the double-sided adhesive sheet 30 is positioned and bonded on the fixing sheet 9 so that the through holes 30a to 30f correspond to the metal domes 8a to 8f, and the EL sheet E is bonded thereon. (1) A plurality of illuminated switches can be easily formed on one switch substrate. If a plurality of slits are provided in all of the through holes 30a to 30f, the double-sided adhesive sheet 30 is separated, and the alignment becomes complicated. It is desirable that one of the through holes 30a to 30f communicating with each other has one slit.
[0022]
The operation of the illuminated switch is such that the metal domes 8a to 8f are deformed by applying a load to the apexes of the desired metal domes 8a to 8f via the switch operating member, and the pair of fixed contacts 7a and 7b are short-circuited. Are closed and the metal domes 8a to 8f are elastically restored by releasing the load, and the short-circuit between the pair of fixed contacts 7a and 7b is eliminated, and the switch is opened. Since only the EL sheet E and the fixing sheet 9 are covered on the metal domes 8a to 8f, a remarkable increase in load and a decrease in click feeling are not caused. When the EL sheet E is adhered using the double-sided adhesive sheet 20 of FIG. 6, when a metal dome is pressed to close any switch, air is trapped in the through holes 20a to 20f and slightly compressed. As a result, the load is slightly increased and the click feeling is slightly inferior. However, when the EL sheet E is adhered using the double-sided adhesive sheet 30 of FIG. 7, when the metal dome is pressed to close any of the switches, the air in the through holes 30a to 30f loses the slits 31a to 30f. Through 31e, it is possible to move to an adjacent through-hole, and the slit and the adjacent through-hole act as an escape for air. Therefore, when the switch is operated, the switch operation load does not significantly increase and the click feeling does not decrease.
[0023]
Incidentally, the adhesive member is not limited to the double-sided adhesive sheet, and an adhesive or an adhesive can be used. The adhesive may be formed on the protective layer 16 of the EL sheet E by printing in a shape similar to that shown in FIGS. 3, 6, and 7 by a method such as a screen printing method.
[0024]
【The invention's effect】
As described above, in the illumination switch of the present invention, when the EL sheet is bonded onto the fixing sheet, the portion corresponding to the movable contact is adhered to the periphery of the movable contact as a non-adhesive portion. A switch operation load can be extremely reduced, a good click feeling can be obtained, and an illuminated switch with good usability can be provided. Since the EL sheet and the fixing sheet are adhered to each other with the double-sided adhesive sheet, and the non-adhered portion is constituted by the through hole, the constitution can be simplified. Further, since a slit communicating with the plurality of through-holes is provided, a better click feeling can be obtained when the switch is operated.
[Brief description of the drawings]
FIG. 1 illustrates one embodiment of the present invention, and is a cross-sectional view of an EL sheet.
FIG. 2 is a cross-sectional view illustrating a configuration of a switch.
FIG. 3 is an enlarged cross-sectional view showing an example of a double-sided adhesive sheet for bonding an EL sheet on the switch of FIG. 2 in a thickness direction.
FIG. 4 is a cross-sectional view illustrating a configuration of a switch to which an EL sheet is fixed.
FIG. 5 is an enlarged sectional view of an illuminated switch on which a switch operating member is arranged.
FIG. 6 is an enlarged cross-sectional view showing another example of the double-sided adhesive sheet in a cross section in a thickness direction.
FIG. 7 is an enlarged cross-sectional view showing still another example of the double-sided adhesive sheet in a cross section in a thickness direction.
FIG. 8 is an enlarged sectional view of a conventional illumination switch.
FIG. 9 is an enlarged cross-sectional view showing the double-sided adhesive sheet used in FIG. 8 in a cross-section in a thickness direction.
[Explanation of symbols]
E EL sheet 7 Switch boards 7a, 7b Fixed contacts 8, 8a to 8f Movable contacts (metal dome)
9 Fixing sheets 10, 20, 30 Double-sided adhesive sheet 10a Through holes 20a to 20f Through holes 30a to 30f Through holes 31a to 31e Slit

Claims (4)

The switch board has fixed contacts,
Above the switch board, a dome-shaped movable contact that is brought into contact with and separated from the fixed contact by elastic deformation is provided,
Above the movable contact, a fixing sheet that is joined to the movable contact and the switch board and fixes the movable contact between the movable contact and the switch board is provided,
An EL sheet to be joined to the fixing sheet is provided above the fixing sheet,
The illuminating switch, wherein the EL sheet and the fixing sheet are adhered to each other around the movable contact, with a portion corresponding to the movable contact being a non-adhesive portion. The through-hole according to claim 1, wherein the EL sheet and the fixing sheet are bonded via a double-sided adhesive sheet, and the double-sided adhesive sheet forms the non-adhesive portion at a portion corresponding to the movable contact. An illuminated switch characterized in that a light switch is formed. 3. An illuminated switch according to claim 2, wherein a plurality of said movable contacts are provided, and said through holes are respectively formed in portions corresponding to said movable contacts. The illuminated switch according to claim 3, wherein the double-sided adhesive sheet has a slit communicating with the adjacent through-hole.

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