JP2007173184A - Key-sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a key-sheet with good appearance and good design, having a plurality of key-tops exposed from one operation-opening formed on a case of an apparatus, arranged so as to have narrow gap therebetween, an elastic base-sheet made of rubber on which the key-tops are mounted, and a reinforcing member made of metallic thin plate regulating distortion of the base-sheet. <P>SOLUTION: On the key sheet 11, metal plate cover layers 17 are arranged on a part at least visible from outside of key-top side surface 13a of the reinforcing member 13 made of metallic thin plate, by the above, metallic color of the reinforcing member 13 made of metallic thin plate is invisible from the gap between adjacent key-tops 14, 14 or from the gap between the key-top 14 and the case 1a of the apparatus 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a key sheet for a push button switch used in an operation unit of various devices such as a mobile phone, a PDA, a car navigation device, and a car audio device, and in particular, a plurality of key tops are formed from one operation opening formed in a housing of the device. The present invention relates to a key sheet suitable for use when exposed.

A communication device such as a mobile phone and a consumer device are formed in a housing 1a as in the case of the mobile phone 1 shown in FIG. A key sheet 3 for a push button switch is known in which a plurality of key tops 2 are exposed from a single operation opening 1b in a narrow space of about 0.15 mm to 0.2 mm. As shown in FIG. 10, the key sheet 3 has a plurality of key tops 2 fixed to a base sheet 4 made of a rubber-like elastic body, and presses the outer edge side portion 4 a of the base sheet over the entire circumference. The base sheet 4 is reinforced with a reinforcing member 5 such as a hard resin or a hard film so that the key sheet 3 does not bend because it is held and not restrained inside the pressure contact portion. The key sheet 3 is described in, for example, Japanese Patent Application Laid-Open No. 2004-319396 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2005-190849 (Patent Document 2).
JP 2004-319396 A JP 2005-190849 A

  However, due to the demand for further thinning of various devices, the key sheet for the push button switch is also required to be thin, and the key top, base sheet, and reinforcing member constituting the key sheet are made thinner than ever. ing. However, it is difficult to make the reinforcing member thinner than before as long as a hard film or a hard resin is used. Therefore, it has been studied to use a thin metal plate that can be made thinner if the strength is the same instead of a hard film or a hard resin. However, when the key top is also made thinner, the height between the reinforcing member and the key top becomes lower, so that the portion of the ground that can be seen from the gap between the key tops becomes conspicuous. Therefore, when a metal thin plate is used, the metal color of the metal thin plate different from the key top is visually recognized, resulting in a key sheet that does not look good.

  Therefore, the present invention has a good appearance and excellent design, particularly in a key sheet in which the key tops are arranged narrowly and the key top, base sheet, and reinforcing member constituting the key sheet are thin. The purpose is to provide a key sheet.

  In order to achieve the above object, the present invention provides a plurality of key tops exposed from one operation opening formed in a casing of a device, a base sheet made of a rubber-like elastic body on which the key top is placed, and distortion of the base sheet. A key sheet comprising a reinforcing member made of a thin metal plate that regulates a key sheet, wherein the key sheet is provided with a metal plate covering layer at least at a site visible from the outside of the key top side surface of the reinforcing member made of a thin metal plate I will provide a.

  Since the reinforcing member made of a metal thin plate is used, the thickness of the reinforcing member can be reduced as compared with the case where a resin film or a resin thin plate is used. In addition, the surface of the reinforcing member made of a thin metal plate can be seen from the gap between adjacent key tops or the gap between the key top and the housing of the device. Since the metal plate covering layer is provided at such a portion, the metal color of the reinforcing member is not seen. Therefore, it can be set as a good-looking key sheet.

  The metal plate covering layer can have the same color as the key top surface. If the metal plate cover layer and the keytop surface are similar in color, the gap between adjacent keytops and the gap between the keytop and the housing of the device will not be noticeable, and the gap will feel narrow, and the entire keytop Can be made into a key sheet with a good appearance.

  The thickness of the reinforcing member made of a thin metal plate can be 50 μm to 2000 μm. If the thickness of the reinforcing member made of a thin metal plate is 50 μm to 2000 μm, it is possible to prevent the key sheet from being distorted or bent when the key sheet is mounted on a device. Further, it is possible to prevent deterioration of the operational feeling due to the difference in the amount of pressing strokes, and the mutual penetration of the key tops. In addition, the thickness of the entire key sheet can be reduced.

  Furthermore, an illumination type key sheet in which the key top is illuminated by light emitted from an illumination light source provided inside the device, and the light absorption color is a light absorption color at a position facing the illumination light source on the bottom surface of the reinforcing member made of a thin metal plate. A layer can be provided. Since the light absorption layer is provided on the bottom surface of the reinforcing member made of thin metal plate in a position facing the illumination light source provided in the device, the light that directly hits the reinforcing member made of thin metal plate from the illumination light source such as LED is absorbed. It is possible to prevent occurrence of uneven illumination of the key top around the light source.

  According to the key sheet of the present invention, the thickness of the key top, the base sheet, and the reinforcing member made of a thin metal plate can be reduced, thereby further reducing the thickness of the entire key sheet, and the gap between the key tops is not noticeable. It is a good key sheet with good design.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, a key sheet for a push button switch applied to a mobile phone as “apparatus” will be described. In the following description, the term “reinforcing member” means a reinforcing member made of a thin metal plate unless otherwise specified.

1st Embodiment [FIGS. 1-4] ; The key sheet 11 by 1st Embodiment is shown with the top view of FIG. 1, the bottom view of FIG. 2, and sectional drawing of FIG. 3, FIG. As shown in these drawings, the key sheet 11 has a layer structure in which a reinforcing member 13 made of a thin metal plate is provided on a base sheet 12 made of a rubber-like elastic body, and a key top 14 is further laminated thereon. ing.

  In the base sheet 12 in the present embodiment, the upper surface 12a side is fixed to the reinforcing member 13. That is, the through hole 15 of the reinforcing member 13 is fitted into the base portion 12c of the base sheet 12, and the base sheet 12 and the reinforcing member 13 are integrated. Further, a pusher 12d and a thick portion 12e placed on a substrate (not shown) are provided on the bottom surface 12b side. As shown in FIGS. 2 and 4, the thick portion 12e is provided with a recess 12f into which an LED (not shown) or the like serving as an illumination light source enters.

  The key top 14 is fixed to the base portion 12 c via the adhesive 16. Further, the reinforcing member 13 is provided with a metal plate coating layer 17 of the same color as the upper surface 14a of the key top 14 on the upper surface 13a. Further, a light absorption layer 18 is provided on the bottom surface 13b of the reinforcing member 13 at a portion facing the LED.

  As the rubber-like elastic body forming the base sheet 12, thermosetting elastomers such as silicone rubber, isoprene rubber, ethylene propylene rubber, butadiene rubber, chloroprene rubber, and natural rubber, which have good resilience and flexibility, can be used. Also, thermoplastic elastomers such as styrene, ester, urethane, olefin, amide, butadiene, ethylene-vinyl acetate, fluororubber, isoprene, and chlorinated polyethylene can be used. Of these, silicone rubber, styrene-based thermoplastic elastomer, and ester-based thermoplastic elastomer are preferable because they have excellent impact resilience and high durability.

  Since the reinforcing member 13 is required to have a thin plate thickness, a thin metal plate having rigidity even if thin is used. More specifically, a metal thin plate such as stainless steel, aluminum, chromium, gold, silver, copper, nickel, tin can be used, but stainless steel, aluminum, gold, copper, etc. that can be easily formed into a thin plate shape should be used. Is preferred. The reinforcing member 13 preferably has a thickness of 50 μm to 2000 μm. If it is less than 50 μm, the rigidity is weak and it is difficult to suppress the distortion of the key sheet 11, and if it exceeds 2000 μm, the entire key sheet becomes too thick and is not realistic. An earthing portion 13c is provided at the end of the reinforcing member 13, so that erroneous input due to static electricity can be prevented and antifouling can be achieved.

  The metal plate covering layer 18 provided on the upper surface 13a of the reinforcing member 13 protects the reinforcing member 13 and covers the reinforcing member 13 so as not to show its metal color. Metal by the dipping method dipping in the liquid having a desired color tone, the printing method such as screen printing, tampo printing, transfer printing, spray coating method, etc. with respect to the reinforcing member 13 having the through holes 15 formed by punching or laser processing A plate covering layer 18 can be provided. If the color of the metal plate covering layer 18 is similar to the surface of the key top 14, not only does the metal color disappear from the gap between the key tops 14, 14, but the boundary of the key top 14 is not emphasized. The key sheet 11 can be made to feel narrow.

  The light absorption layer 22 provided on the bottom surface 13b of the reinforcing member 13 is a thin layer having a light absorption color such as black, and is a so-called illumination type in which an illumination light source inside the device 1 emits light to illuminate the key top 14. When the key top 14 is used, it absorbs direct light from the illumination light source and enables uniform illumination without unevenness. That is, if the light absorbing layer 22 is not provided, the light from the illumination light source hits the reinforcing member 13 and is reflected and scattered, so that the key top 14 near the illumination light source becomes too bright compared to the other key tops 14. On the other hand, since there is the light absorption layer 22, the direct light from the illumination light source strikes the light absorption layer 22 and is absorbed, and the other portions are lightly absorbed, so the whole is illuminated uniformly. Therefore, it is suitable for the case of backside illumination in which the back side of the key top 14 shines.

  The key top 14 includes a display unit 14c that represents characters, numbers, symbols, graphics, and the like, and is a portion where a pressing operation with a finger is actually performed. It is formed using a hard resin such as a thermoplastic resin or a thermosetting resin, or a rubber-like elastic body such as a silicone rubber or a thermoplastic elastomer. The thickness of the entire key sheet 11 is required to be thin, and is preferably 0.5 mm to 2 mm, more preferably about 1 mm. When used as an illuminated key sheet, a transparent material such as polycarbonate is used. Moreover, a character part can be illuminated by giving a surface decoration in the shape of a letter.

  In order to manufacture the key sheet 11 as described above, first, the reinforcing member 13 is formed in a predetermined shape, and the metal plate covering layer 21 is provided by dipping or the like. Next, when a thermosetting elastomer is selected, it is placed in a mold cavity for molding the thermosetting elastomer, and when a thermoplastic elastomer is selected, an injection mold for the thermoplastic elastomer is selected. The reinforcing member 13 is transferred into the cavity. Thereafter, a rubber-like elastic body serving as the base sheet 12 is injected and molding is performed. Thus, the base sheet 12 and the reinforcing member 13 are integrally formed. Finally, the base portion 12 c of the base sheet and the bottom surface of the key top 14 are aligned and fixed with the adhesive 16. In this way, the key sheet 11 is obtained. In the above manufacturing method, it is also possible to fix the base sheet 12 and the reinforcing member 13 separately molded with an adhesive (not shown).

  In the key sheet 11, the key top 14 is formed thin, but the reinforcing member 13 having the metal plate covering layer 21 is used as the reinforcing member, and the metal color is visually recognized from the gap between the key tops 14, 14. This is a key sheet 11 that does not have a good appearance. The reinforcing member 13 has a light absorption layer 22 on the bottom surface 13b, and the key sheet 11 is capable of uniform illumination without uneven illumination brightness at specific locations.

Second Embodiment [FIGS. 5 and 6] ; The key sheet 21 of the second embodiment is a modification of the first embodiment. 5 and 6 show cross-sectional views. As shown in these figures, the point that the reinforcing member 23 made of a thin metal plate is provided on the bottom surface 22b side of the base sheet 22 is different from the first embodiment. The point which the metal plate coating layer 27 is provided in the upper surface 23a of the reinforcement member 23, and the light absorption layer 28 is provided in the bottom face 13b is the same as 1st Embodiment.

  The key sheet 21 is used as an illuminated key sheet 21, but unlike the key sheet 11 shown in the first embodiment, as shown in FIG. 6, the base sheet 22 is provided with a recess into which the illumination light source enters. Not. That is, the key sheet 21 is used in a configuration in which the illumination light source is disposed below the lower surface 22 b of the base sheet 22 when mounted on the device 1. The key sheet 21 of this embodiment can also be manufactured by the same method using the same material as the key sheet 11 shown in the first embodiment.

  In the key sheet 21, the key top 24 is formed thin, but the reinforcing member 23 having the metal plate covering layer 27 is used as the reinforcing member, and the metal color is visually recognized from the gap between the key tops 24, 24. This is a key sheet 21 that does not have a good appearance. Further, the bottom 23b of the reinforcing member 23 has the light absorbing layer 28, and the key sheet 21 is capable of uniform illumination without uneven illumination brightness at specific locations.

Third Embodiment [FIGS. 7 and 8] ; A key sheet 31 according to a third embodiment is shown in the cross-sectional views of FIGS. In the key sheet 31 of this embodiment, a reinforcing member 33 made of a thin metal plate is fixed to the bottom surface 32 b of the base sheet 32 so as to partition the base portion 32 c formed on the base sheet 32. A metal plate covering layer 37 is provided on the upper surface 33 a of the reinforcing member 33. The material used in the key sheet 11 of the first embodiment can also be used for the key sheet 31 of the present embodiment.

  The key sheet 31 can be manufactured in the same manner as in the first embodiment. However, since the base sheet 32 is not fitted into the through hole 35 of the reinforcing member 33, the base sheet 32 and the reinforcing member are bonded with an adhesive or an adhesive tape. It is easier to fix 33.

In the above embodiment, the key sheets 11, 21, and 31 used for the mobile phone 1 are exemplified, but can be used for other devices such as a PDA and a remote controller.

The external appearance top view of the key sheet by a 1st embodiment. The bottom view of the key sheet | seat of FIG. SB-SB sectional view of the key sheet of FIG. SC-SC sectional drawing of the key sheet of FIG. Sectional drawing equivalent to FIG. 3 of the key sheet by 2nd Embodiment. Sectional drawing equivalent to FIG. 4 of the key sheet | seat of FIG. Sectional drawing equivalent to FIG. 3 of the key sheet by 3rd Embodiment. Sectional drawing equivalent to FIG. 4 of the key sheet | seat of FIG. FIG. Sectional drawing of the conventional key sheet | seat corresponded to the SA-SA line cross section of FIG.

Explanation of symbols

1 Mobile phone (equipment)
DESCRIPTION OF SYMBOLS 1a Case 1b Operation opening 2 Key top 3 Key sheet 4 Base sheet 4a Outer edge side part 5 Reinforcement member 11, 21, 31 Key sheet 12, 22, 32 Base sheet 12a, 22a, 32a (base sheet) upper surface (surface)
12b, 22b, 32b (base sheet) bottom surface 12c, 22c, 32c Base 12d, 22d, 32d Pusher 12e, 22e, 32e Thick part 12f, 22f, 32f Recess 13, 23, 33 Reinforcement made of thin metal plate Member 13a, 23a, 33a Top surface (surface) (of a reinforcing member made of a thin metal plate)
13b, 23b, 33b Bottom surface 13c (of a reinforcing member made of a thin metal plate) Earth portion 14, 24, 34 Key top 14a, 24a, 34a Upper surface (surface) of (key top)
14b, 24b, 34b Bottom surface 14c (of key top) Display portion 15, 25, 35 Through hole 16, 26 Adhesive 17, 27, 37 Metal plate covering layer 18, 28 Light absorbing layer

Claims (4)

A plurality of key tops exposed from one operation opening formed in the housing of the device, a base sheet made of a rubber-like elastic body on which the key top is placed, and a reinforcing member made of a thin metal plate that restricts distortion of the base sheet, In a key sheet comprising
A key sheet comprising a metal plate coating layer at least at a site visible from the outside of a key top side surface of a reinforcing member made of a thin metal plate.   The key sheet according to claim 1, wherein the metal plate covering layer and the key top surface have similar colors.   The key sheet according to claim 1 or 2, wherein the thickness of the reinforcing member made of a thin metal plate is 50 µm to 2000 µm. An illumination type key sheet in which the key top is illuminated by light emitted from an illumination light source provided inside the device, and a light absorption layer having a light absorption color is provided at a position facing the illumination light source on the bottom surface of the reinforcing member made of a thin metal plate. The key sheet according to claim 1, wherein the key sheet is provided.

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