JP2010177202A - Key sheet and structure for mounting the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress distortion of a key sheet with a plurality of key tops arranged at small intervals thereon as much as possible. <P>SOLUTION: In relation to this key sheet 11 including a base sheet 12 and a plurality of key tops arranged on the base sheet 12 and exposed from operation openings formed on a housing of an apparatus and having no partition crosspiece, the base sheet 12 includes: a plurality of floating support parts 15 each formed of a rubber-like elastic body for fixing the key top; and a thin plate-like reinforcing member 13 supporting the floating support parts 15 to be pressingly deformable, and formed of a hard resin. The base sheet 12 is held in the housing in a press contact condition with its outer edge part, and is not constrained with respect to the housing and a circuit board in crosspiece parts separating the floating support parts in its inside from each other. <P>COPYRIGHT: (C)2010,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 more particularly, a plurality of keys from an operation opening without a partition rail formed in a device casing. The present invention relates to a key sheet suitable for use with the top exposed, and a method of manufacturing the key sheet.

  Like the cellular phone 1 shown in FIG. 19, a plurality of key sheets 2 are formed from the operation opening 1b without a partition rail formed in the housing 1a due to a request for downsizing of the entire apparatus or the operation unit, a request for design, or the like. There is a demand for a push button switch in which the key top 3 is exposed in a narrow space. As shown in FIG. 20, the key sheet 2 according to this background art is obtained by fixing a plurality of key tops 3, that is, a total of 17 key tops 3 to a base sheet 4 made of silicone rubber. That is, one large key top 3a for inputting the vertical and horizontal directions at the center upper part, four small key tops 3b at the left and right, and twelve medium key tops below them. 3c. The interval between the adjacent key tops 3a, 3b, 3c is very narrow, for example, it is arranged between 0.15 mm and 0.2 mm, and the gap with the operation opening 1b is also the same and very narrow. The related art of the key sheet 2 having such a narrow arrangement is described in Patent Document 1, for example.

Japanese Patent Application No. 2003-114833

  As shown in FIG. 21, such an attachment structure of the key sheet 2 is a structural element inside the housing 1a. In this background art, the opening edge side portion of the operation opening 1b on the back surface 1c of the housing 1a and the housing 1a. And a circuit board 1d built in, and the outer edge side portion of the base sheet 4 is held in pressure contact over the entire periphery, and the mounting structure does not restrain the casing 1a or the circuit board 1d inside the pressure contact portion. It has become. Therefore, when the cellular phone 1 is used, when the key sheet 2 is erected as shown in FIG. 22, for example, or is tilted downward as shown in FIG. 23, the base sheet 4 made of a rubber-like elastic body such as flexible silicone rubber is obtained. Depending on the weight load of the key top 3, it may extend and be distorted as a whole. Thus, when the key sheet 2 is distorted as a whole, a displacement occurs between the pusher 4a of the base sheet 4 and the contact switch 1e formed of the metal disc spring and the contact circuit of the circuit board 1d. An operation failure may occur in which it is impossible to input even if the key top 3 is pressed, or it is difficult to input. In addition, the pressing stroke amount at the time of input differs for each key top 3 depending on the distortion mode of the base sheet 4, and the operability may be adversely affected. Furthermore, there is a problem that the appearance of the mobile phone 1 is impaired. Also, one adjacent key top 3 may slide sideways and sink under the other key top 3.

The problems caused by the distortion of the base sheet 4 made of a flexible rubber-like elastic body as described above are particularly solved for the key sheet 2 that exposes all the key tops 3 through the operation openings 1b as shown in the figure. It should be a problem. However, for example, these problems may occur when one operation opening is provided in the casing 1a for the top and bottom key tops 3b, that is, when there are two or more key tops arranged per single operation opening. Can happen. In addition, even when a key sheet having a plurality of key tops arranged between a plurality of key tops is attached to a device that is not expected to stand upright or tilt like the mobile phone 1, a base made of a flexible rubber-like elastic body is used. Since problems such as the penetration of key tops may occur due to sheet distortion, countermeasures are similarly demanded for these key sheets as well.
The present invention has been made against the background of the above technique. The purpose is to suppress as much as possible distortion of a key sheet in which a plurality of key tops are arranged narrowly.

  In order to achieve the above object, the present invention relates to a key sheet comprising a base sheet and a plurality of key tops that are disposed on the base sheet and exposed from an operation opening without a partition rail formed in a housing of the device. Is configured to include a plurality of floating support portions made of rubber-like elastic bodies to which the key tops are fixed, and a thin plate-like reinforcing member made of hard resin that supports the floating support portions so as to be capable of being pressed and displaced.

  According to the key sheet of the present invention, the key top is supported by the floating support portion, and the floating support portion is supported by the thin plate-like reinforcing member made of hard resin to improve the rigidity of the base sheet. By the reinforcing member, it can be almost eliminated or eliminated. Therefore, various problems caused by distortion of the base sheet, that is, poor operation due to misalignment between the key top and the contact switch, deterioration of operability due to different pressing stroke amount for each key top, It is possible to eliminate the negative effects and the sneaking in between key tops.

  The key sheet of the present invention can be constituted by using a heat-resistant hard resin having a deflection temperature under load measured according to JIS K 7191 of 170 ° C. or more as the reinforcing member.

  Since the reinforcing member is manufactured from a heat-resistant hard resin having a deflection temperature under load of 170 ° C. or higher measured according to JIS K 7191, the rigidity of the base sheet is improved, it is less susceptible to thermal deformation, and has good dimensional accuracy without warping. A key sheet is obtained. JIS K 7191 describes a test method for the deflection temperature under load. Unless otherwise specified, the “deflection temperature under load” refers to the deflection temperature under load measured according to JIS K 7191.

  As this hard resin, a heat-resistant hard resin selected from polyarylate resin, polyallylsulfone resin, polyethersulfone resin, and polysulfone resin can be used.

  When these resins are used, they are rigid and have excellent heat resistance.For example, when the floating support portion made of a reinforcing member and a rubber-like elastic body is integrally formed by mold molding, it is used during molding or removal. Thermal deformation that tends to occur during molding can be suppressed, and a key sheet with high dimensional accuracy can be obtained. In addition, when using an illuminated key sheet, if these resins are transparent, the transparency of the material itself is high, and therefore, an illuminated key sheet with excellent light transmissivity with good light transmission from the internal light source and can do.

  Moreover, the heat resistant polycarbonate resin containing the structural unit represented by following General formula (1) can be used for this hard resin.

（式中、Ｘは炭素、ｍは４〜７の整数を表す。Ｒ^１及びＲ^２は、各Ｘに対して個々に選択することができ、かつ相互に独立して水素または炭素数１〜６のアルキルを表す。また、ｎは４０〜１００の整数を表す。）

(Wherein X represents carbon, m represents an integer of 4 to 7. R ¹ and R ² can be individually selected for each X, and are independently hydrogen or 1 to 6 represents alkyl, and n represents an integer of 40 to 100.)

  If this resin is used, it is rigid and has excellent heat resistance.For example, when a floating support portion made of a reinforcing member and a rubber-like elastic body is integrally formed by molding, shaping or demolding is performed. Thermal deformation that tends to occur sometimes can be suppressed, and a key sheet with high dimensional accuracy can be obtained. In addition, when using an illuminated key sheet, if these resins are transparent, the transparency of the material itself is high, and therefore, an illuminated key sheet with excellent light transmissivity with good light transmission from the internal light source and can do.

  About the key sheet | seat of the said invention, the hard resin which comprises a reinforcement member can be comprised as what contains a resin reinforcement.

  According to this, since the rigidity of the hard resin is greatly improved, the distortion of the base sheet can be eliminated.

  The resin reinforcing material of the present invention includes a scaly resin reinforcing material, a clod-like resin reinforcing material, a fibrous resin reinforcing material, and a spherical resin reinforcing material.

  If these resin reinforcing materials are used, the hard resin can be easily filled, the workability of the hard resin after molding is good, and a high reinforcing effect can be obtained. Mica powder, graphite powder, etc. can be used as the scale-like resin reinforcement, graphite powder, etc. can be used as the clod-like resin reinforcement, and glass sphere, silica sphere, etc. can be used as the spherical resin reinforcement. Can be used. And as a fibrous resin reinforcement, the following can be used.

  That is, the resin reinforcing material of the present invention is configured to contain at least one of glass fiber, metal fiber, carbon fiber, aramid fiber, or ceramic fiber.

  In addition to being able to exert an excellent rigidity improvement effect, these fiber materials are also excellent in heat resistance. For example, when a floating support portion made of a rubber-like elastic body is integrally formed on a reinforcing member by molding In addition, it is possible to suppress thermal deformation of the hard resin that forms the reinforcing member that is likely to occur during molding or demolding, and a highly accurate key sheet can be obtained.

  Specific configurations of the above key sheet include a form in which a base member is a reinforcing member made of a hard resin as a whole and a floating support portion is provided on the reinforcing member, and the whole base sheet is made of rubber such as silicone rubber or thermoplastic elastomer. This can be realized as a configuration in which an elastic sheet made of a cylindrical elastic body is used as a base and a reinforcing member is partially provided on the elastic sheet. In this application, the following invention is provided as the concrete structure.

  In other words, in the key sheet of the present invention described above, the reinforcing member is constituted by a single plate having a through hole for bridging and fixing the floating support portion.

  According to the present invention, since the reinforcing member is a single plate, the overall distortion of the key sheet can be reliably suppressed by improving the overall rigidity. In this case, fixation between the through hole of the reinforcing member and the floating support portion can be realized by integral molding by die molding or adhesion using an adhesive. In addition, if it is the integral molding by mold molding, especially a fixed strength and productivity can be improved.

  In the above key sheet of the present invention, the base sheet is formed of an elastic sheet made of a rubber-like elastic body having a floating support portion, and the reinforcing member is partially provided between the adjacent floating support portions. Configured as a thing.

  According to the present invention, while the base sheet is formed of an elastic sheet, it is possible to reliably suppress the occurrence of distortion of the key sheet by improving the rigidity of the reinforcing member provided between the adjacent floating support portions. In this case, the reinforcing member can be provided, for example, in the form of integral molding with an elastic sheet by molding, adhesion to the elastic sheet, or application of a liquid resin forming the reinforcing member to the elastic sheet and curing.

  In the key sheet of the present invention described above, the base sheet is formed of an elastic sheet made of a rubber-like elastic body having a floating support portion, and a reinforcing member is provided on the outer edge side of the elastic sheet.

  According to the present invention, while the base sheet is formed of an elastic sheet, it is possible to reliably suppress the occurrence of distortion of the key sheet by improving the rigidity at the outer edge of the elastic sheet by the reinforcing member. In this case, the reinforcing member can be provided, for example, in the form of integral molding with an elastic sheet by molding, adhesion to the elastic sheet, or application of a liquid resin forming the reinforcing member to the elastic sheet and curing.

  The key sheet of the present invention described above is configured as a base sheet provided with a pressure contact receiving portion made of a rubber-like elastic body.

  According to the present invention, by compressing and holding the pressure contact receiving portion, the key sheet can be reliably held in the device by the rebound resilience of the pressure contact receiving portion made of a rubber-like elastic body.

  Further, the present invention relates to a method of manufacturing a key sheet in which a plurality of key tops exposed from an operation opening without a partition rail formed in a housing of an apparatus are fixed to a base sheet, and a load deflection measured based on JIS K 7191. A reinforcing member is manufactured using a heat-resistant hard resin having a temperature of 170 ° C. or higher, the reinforcing member is transferred to a cavity of a base sheet molding die, and a rubber-like elastic body is placed in the cavity. The key sheet manufacturing method is configured to manufacture the base sheet by integrating the rubber-like elastic body and the reinforcing member at a temperature lower than the deflection temperature under load of the hard resin.

  According to the present invention, a reinforcing member is manufactured using a heat-resistant hard resin having an excess deflection temperature measured in accordance with JIS K 7191 of 170 ° C. or higher, and the reinforcing member is transferred to a cavity of a base sheet molding die. A rubber-like elastic body is placed in the cavity, and the rubber-like elastic body and the reinforcing member are integrated at a temperature lower than the deflection temperature under load of the heat-resistant hard resin to produce a base sheet. Thus, a key sheet with high dimensional accuracy can be obtained because the reinforcing member hardly undergoes thermal deformation at the time of integral molding or demolding. If a resin having a predetermined deflection temperature or higher is selected, it is necessary to prepare a plurality of reinforcing member manufacturing molds corresponding to the type of the resin in consideration of the degree of “warping” according to the type of the resin. In addition, a complicated design considering the degree of “warping” is not required, and the manufacture of the reinforcing member manufacturing mold is facilitated, so that the manufacturing cost can be reduced.

  If a thermosetting elastomer is used for the rubber-like elastic body, the thermosetting elastomer and the reinforcing member are used at a temperature that is not lower than the curing temperature of the thermosetting elastomer and lower than the deflection temperature of the heat-resistant hard resin used for the reinforcing member. A base sheet can be manufactured integrally.

  Since the thermosetting elastomer and the reinforcing member are integrated at a temperature that is equal to or higher than the curing temperature of the thermosetting elastomer and less than the deflection temperature under load of the heat-resistant hard resin used for the reinforcing member, the thermosetting elastomer is placed in the mold. Even when heated to the temperature for crosslinking (vulcanization) curing, the reinforcing member does not undergo thermal deformation because it is below the deflection temperature under load of the heat-resistant hard resin. Therefore, it is possible to obtain a key sheet that does not affect the curing temperature of the thermosetting elastomer and does not undergo thermal deformation such as warping.

  If the rubber-like elastic body is silicone rubber, the base sheet can be manufactured by integrating the silicone rubber and the reinforcing member at a temperature of 160 ° C. or higher and lower than the deflection temperature under load of the heat-resistant curable resin used for the reinforcing member. .

  Since the silicone rubber and the reinforcing member are integrated at a temperature of 160 ° C. or higher and less than the deflection temperature under load of the heat-resistant curable resin used for the reinforcing member, even if the temperature is increased to 160 ° C. or higher for crosslinking and curing the silicone rubber, Since the temperature is lower than the deflection temperature under load of the resin, the reinforcing member does not undergo thermal deformation. Therefore, it is possible to obtain a key sheet that does not affect the curing temperature of the silicone rubber and does not undergo thermal deformation such as warping.

  According to the key sheet of the present invention, the configuration of the reinforcing member made of a hard resin increases the rigidity of the base sheet, and the occurrence of distortion of the base sheet is almost eliminated or eliminated. For this reason, various problems due to distortion of the base sheet, that is, poor operation due to misalignment between the key top and the contact switch, deterioration of operability due to the difference in pressing stroke amount for each key top, and equipment design This is a key sheet that can eliminate the negative effects of the key tops and eliminate the sneaking between key tops.

  In particular, when a resin reinforcing material is contained in the hard resin forming the reinforcing member, the rigidity of the hard resin is remarkably improved and the distortion of the base sheet can be eliminated. Furthermore, when it contains at least one of glass fiber, metal fiber, carbon fiber, aramid fiber, or ceramic fiber as a resin reinforcing material, in addition to excellent rigidity improvement effect, reinforcement that is likely to occur at the time of molding or demolding Since heat deformation of the hard resin constituting the member can be suppressed and a highly accurate key sheet can be obtained, even a key sheet having a complicated design form can be mass-produced with a high yield.

  Further, when a heat-resistant hard resin having a deflection temperature under load of 170 ° C. or higher is used for the hard resin as the reinforcing member, a key sheet with high dimensional accuracy can be obtained without being thermally deformed in the key sheet manufacturing process. Therefore, manufacturing costs can be reduced.

As described above, the key sheet of the present invention can solve various problems caused by the distortion of the base sheet, and therefore depends on a method that adversely affects operability, that is, downsizing the size of the key top itself. Therefore, it is possible to meet the demand for downsizing the entire device and downsizing the operation unit.
Moreover, according to the key sheet manufacturing method of the present invention, a key sheet with high dimensional accuracy can be obtained without causing thermal deformation such as warpage of the key sheet, and a high-quality and inexpensive key sheet is manufactured. Is possible.

The external view of the bottom face of the key sheet by 1st Embodiment. SB-SB sectional view taken on the line of FIG. The SC-SC sectional view taken on the line of FIG. The external view of the bottom face of the key sheet by 2nd Embodiment. SD-SD sectional view taken on the line of FIG. SE-SE line expansion principal part sectional drawing of FIG. The external view of the bottom face of the key sheet by 3rd Embodiment. SF-SF sectional view taken on the line of FIG. The external view of the bottom face of the key sheet by 4th Embodiment. SG-SG sectional view taken on the line of FIG. The external view of the bottom face of the key sheet by 5th Embodiment. FIG. 12 is a cross-sectional view taken along the line SH-SH in FIG. 11. The external view of the upper surface of the key sheet by 5th Embodiment. FIG. 14 is a cross-sectional view taken along line SI-SI in FIG. 13. The expanded principal part sectional drawing which shows the modification of 1st, 2nd, 3rd embodiment. The expanded principal part sectional view which shows the modification of 5th Embodiment. The expanded principal part sectional view which shows the modification of 5th Embodiment. The expanded principal part sectional view which shows the modification of 5th Embodiment. The external appearance perspective view of the mobile phone by a prior art example. FIG. 20 is an external view of a key sheet provided in the mobile phone of FIG. 19. FIG. 20 is a schematic cross-sectional view of the mobile phone along the line SA-SA in FIG. 19. FIG. 22 is a schematic cross-sectional view corresponding to FIG. 21 showing a state in which the cellular phone is upright. FIG. 22 is a schematic cross-sectional view corresponding to FIG. 21 showing a state in which the mobile phone is tilted.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, duplication description is abbreviate | omitted about the structure which is common in a prior art, and the structure which is common in each embodiment. In the following description, a key sheet for a push button switch applied to the mobile phone 1 will be described as an example of “apparatus” as in the description of the related art.

1st Embodiment [FIGS. 1-3] ; The key sheet 11 of this form is comprised by the base sheet 12 and the key top 3 fixed to the base sheet 12. FIG.

  The base sheet 12 has a rounded rectangular shape with a rectangular tongue piece on the top, and includes a single hard resin plate 13 as a “reinforcing member”. A rectangular through hole 14 is formed in the hard resin plate 13 at a portion where each key top 3 is provided by a lattice-shaped crosspiece 13a. The through hole 14 is closed by a floating support portion 15 made of a rubber-like elastic body. 2 and 3, the floating top 15 has a key top 3 fixed to the top surface thereof with an adhesive not shown in the figure, and a cylindrically shaped push that projects downward on the bottom surface. A child 16 is formed. In addition, a flexible portion 17 is formed on the floating support portion 15, and the key top 3 is floatingly supported so as to be displaceable by pressing downward in the drawing.

  Here, the material of each part constituting the base sheet 12 will be described. First, the hard resin plate 13 is made of a material having high rigidity so as to suppress the distortion of the key sheet 11. Examples of the material of the hard resin plate 13 include polycarbonate resin, polymethyl methacrylate resin, polypropylene resin, polystyrene resin, polyacrylic copolymer resin, polyolefin resin, acrylonitrile butadiene styrene resin, polyester resin, and epoxy resin. Polyamide resins including polyurethane resins, polyimide resins, polyamideimide resins, amino resins such as silicone resins, melamine resins, allyl resins, furan resins, phenolic resins, fluororesins, polyarylate resins, polyallylsulfone resins, Polyether sulfone resin, polyphenylene ether resin, polyphenylene sulfide resin, polysulfone resin and the like can be used.

  Among these resins, it is preferable to use a heat-resistant hard resin having a deflection temperature under load of 170 ° C. This is for preventing the hard resin plate 13 from being deformed by warping or the like due to heating when the base sheet 12 is manufactured. These resins include, for example, 180 ° C. amino resin, 180 ° C. melamine resin, 200 ° C. allyl resin, 230 ° C. epoxy resin, 170 ° C. furan resin, 200 ° C. phenol resin, 300 ° C. silicone resin, 200 ° C fluorine resin, 270 ° C polyamideimide resin, 175 ° C polyarylate resin, 204 ° C polyallylsulfone resin, 200 ° C polyethersulfone resin, 240 ° C polyimide resin, 172 ° C polyphenylene ether resin, 260 And a polyphenylene sulfide resin at 175 ° C, a polysulfone resin at 175 ° C, and a polycarbonate resin at 180 ° C. Furthermore, among these resins, for example, a polycarbonate resin containing a structural unit represented by the following general formula (1), a polyarylate resin, a polyallyl sulfone resin, a polyether sulfone resin, or a polysulfone resin is more preferable. . The polycarbonate resin containing the structural unit represented by the following general formula (1) is more preferable because the deflection temperature under load of these resins is 170 ° C. or higher, and the crosslinking temperatures of many resins containing silicone rubber This is because they are not thermally deformed and the adhesive strength between the resin and the rubber-like elastic body is high. In addition, since the transparency is high, when a so-called illuminated key sheet that is illuminated by an internal light source is used, the light from the light source can be efficiently illuminated.

（式中、Ｘは炭素、ｍは４〜７の整数を表す。Ｒ^１及びＲ^２は、各Ｘに対して個々に選択することができ、かつ相互に独立して水素または炭素数１〜６のアルキルを表す。また、ｎは４０〜１００の整数を表す。）

(Wherein X represents carbon, m represents an integer of 4 to 7. R ¹ and R ² can be individually selected for each X, and are independently hydrogen or 1 to 6 represents alkyl, and n represents an integer of 40 to 100.)

  The structural unit represented by the general formula (1) includes structural units represented by the following formulas (2) to (4).

（各式中、ｎは相互に独立して４０〜１００の整数を表す。）

(In each formula, n represents an integer of 40 to 100 independently of each other.)

  The structural unit represented by the general formula (1) and the formula (1) to the formula (4) is 40 to 100 mol% with respect to the whole polycarbonate resin, and the general formula (1) and the formula (1). ) To Formula (4) are bonded with H, OH, OR, COOR (R is hydrogen or an alkane having 1 to 3 carbon atoms), etc., depending on the type of raw material.

  A resin reinforcing material can be mixed with the hard resin that is the base material of the hard resin plate 13. The resin reinforcing material is in a substantially uniformly dispersed state in the hard resin plate 13 after curing, and the rigidity is improved over the entire surface of the hard resin plate 13.

  Examples of such resin reinforcing materials include scale-like resin reinforcing materials such as mica powder and graphite powder, earth-like resin reinforcing materials such as graphite powder, glass fibers, carbon fibers, aramid fibers, ceramic fibers, and metal fibers. Spherical resin reinforcements such as fibrous resin reinforcements, glass spheres, and silica spheres are used. When these resin reinforcing materials are used, it is easy to fill the uncured liquid hard resin, the workability of the hard resin molding after curing is good, and a high reinforcing effect can be exhibited.

  Among the above resin reinforcing materials, those containing at least one of glass fiber, metal fiber, carbon fiber, aramid fiber, or ceramic fiber are preferable. In addition to being able to exert an excellent rigidity improvement effect, these fiber materials are also excellent in heat resistance. For example, a floating support portion 15 made of a rubber-like elastic body is integrally formed on a hard resin plate 13 by molding. In such a case, it is possible to suppress thermal deformation of the hard resin plate 13 that is likely to occur during molding or demolding, and the key sheet 11 with high accuracy can be obtained.

  The filling amount of the resin reinforcing material as described above varies depending on the shape and material of the selected resin reinforcing material. For example, in the case of a resin reinforcing material such as a scale shape, a lump shape, or a spherical shape, a range of 15 parts by weight to 60 parts by weight is preferable with respect to 100 parts by weight of the hard resin. In the case of a fibrous resin reinforcing material, the range of 10 to 40 parts by weight is preferable with respect to 100 parts by weight of the hard resin. The reason why these are defined is that if each filling amount is less than the lower limit of the above numerical value, a high reinforcing effect cannot be obtained, and a slight distortion may occur due to insufficient rigidity of the hard resin as a base material. It is. Moreover, when each filling amount exceeds the upper limit of the numerical value, filling into the hard resin as the base material becomes extremely difficult, and the mixing processing time becomes long, so that the production efficiency is hindered. Moreover, when the hard resin plate 13 is molded, the hard resin composition filled with the resin reinforcing material exceeding the upper limit value has poor fluidity and cannot be molded into a desired shape.

  As the rubber-like elastic body forming the floating support portion 15, thermosetting elastomers such as silicone rubber, isoprene rubber, ethylene propylene rubber, butadiene rubber, chloroprene rubber, and natural rubber, which have good impact 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 can provide the floating support portion 15 having excellent resilience and high durability.

  In order to manufacture the base sheet 12 as described above, the hard resin plate 13 is obtained in advance by molding such as injection molding. When a thermosetting elastomer is selected as the rubber-like elastic body constituting the floating support portion 15, it is transferred to the cavity of the molding die, and when a thermoplastic elastomer is selected, the injection molding die The molds are transferred to the cavities. Thus, the base sheet 12 in which the floating support portion 15 is integrally formed with the hard resin plate 13 is obtained. Instead of this manufacturing method, the hard resin plate 13 and the floating support portion 15 can be formed by two-color molding.

  When a rubber-like elastic body such as silicone rubber is used when integrally molding the hard resin plate 13 and the rubber-like elastic body in the cavity of the rubber-like elastic body molding die, it is used for crosslinking (vulcanization). In addition, it is necessary to heat the rubber-like elastic body to 150 ° C. or higher, and in some cases to 160 ° C. or higher in the cavity. At that time, if the load deflection temperature of the hard resin plate 13 is low, thermal deformation may occur, resulting in a distorted base sheet 12 containing so-called “sledge”. For this reason, the resin used for the hard resin plate 13 preferably has a deflection temperature under load equal to or higher than the crosslinking temperature of the rubber-like elastic body, and more preferably 170 ° C. or higher. This is because if it is 170 ° C. or higher, it is higher than the crosslinking temperature of many types of rubber-like elastic bodies, and the degree of freedom of temperature setting is increased in the production process. The molding temperature at the time of manufacturing the base sheet 12 is a temperature that takes into account the combination according to the type of the hard resin and the rubber-like elastic body. However, when a thermosetting elastomer is used for the rubber-like elastic body, It is preferable that the temperature is equal to or higher than the curing temperature and lower than the deflection temperature under load of the hard resin used for the hard resin plate 13. Moreover, when using a silicone rubber for a rubber-like elastic body, it is preferable that it is 160 degreeC or more and is less than the deflection temperature under load of the hard resin used for the hard resin board 13. FIG.

  After the base sheet 12 is manufactured, the key sheet 11 of this embodiment is obtained by adhering a predetermined key top 3 to each floating support portion 15.

  The key sheet 11 obtained as described above is based on the hard resin plate 13 containing the resin reinforcing material, and the floating support portion 15 for floatingly supporting the key top 3 is formed in the through hole 14. No distortion occurs. Therefore, even if the key sheet 11 is made upright or tilted to give the hard resin plate 13 the weight of the key top 3, the overall distortion of the key sheet 11 is suppressed by the rigidity of the hard resin plate 13. Therefore, the operation failure due to the positional deviation between the pusher 16 and the contact switch 1e of the circuit board 1d, the deterioration of the operational feeling due to the difference in the pressing stroke amount, the adverse effect on the design of the mobile phone 1, and the intrusion between the key tops are eliminated. Can do.

Second Embodiment [FIGS. 4 to 6] ; The key sheet 21 of this embodiment is different from the first embodiment in that a “reinforcing member” and a “pressure contact” made of a thermoplastic elastomer are applied to the hard resin plate 13 of the base sheet 22. A reinforcing outer frame 23 as a “receiving portion” is integrally formed. By forming the reinforcing outer frame 23 that covers the outer edge of the hard resin plate 13 in this manner, the overall rigidity of the base sheet 21 is further improved as compared with the first embodiment. The reinforcing outer frame 23 made of thermoplastic elastomer is held in pressure contact with the opening edge side portion of the operation opening 1b on the back surface 1c of the casing 1a of the mobile phone 1 and the circuit board 1d built in the casing 1a. On the other hand, due to the rebound resilience, the shape followability with respect to the surface to be pressed is excellent. Therefore, a strong holding force is exhibited, and an excellent sealing property against liquid and dust that tries to enter the housing 1a from the operation opening 1b can be exhibited.

  The key sheet 21 of the second embodiment can be made of the material used in the key sheet 11 shown in the first embodiment, and can be manufactured by molding or two-color molding in the same manner as the key sheet 11. .

Third Embodiment [FIGS. 7 and 8] ; In the base sheet 32 of the key sheet 31 of this embodiment, the front and back surfaces of the crosspiece 13a of the hard resin plate 13 separating the through holes 14 are integrally formed with the floating support section 15. The reinforcing layer 33 as a “reinforcing member” made of a thermoplastic elastomer is formed. The reinforcing layer 33 protects the thin and thin crosspiece 13a from breakage and tearing, thereby increasing the rigidity, improving the overall rigidity of the base sheet 32 compared to the first embodiment, and generating distortion of the key sheet 31. Can be suppressed more reliably.

  The key sheet 31 of the third embodiment can also be manufactured by the same material and the same method as the key sheet 11 shown in the first embodiment.

Fourth Embodiment [FIGS. 9 and 10] ; The key sheet 41 of this embodiment is different from the above-described embodiments in that the base sheet 42 is formed of an elastic sheet 43 made of a thermoplastic elastomer as a rubber-like elastic body. It is different. A reinforcing inner frame 46 as a “reinforcing member” made of a thin plate-like hard resin molding is fixed to the back surface of the flexible portion 17 that separates the floating support portions 44 formed on the elastic sheet 43. Therefore, in this embodiment, the rigidity of the flexible portion 17 is improved by the reinforcing inner frame 46. As a result, the overall rigidity of the base sheet 42 is improved, and the occurrence of distortion of the key sheet 41 can be more reliably suppressed.

  In order to manufacture such a base sheet 42, the reinforcing inner frame 46 is manufactured by molding such as injection molding. The base sheet 42 can be obtained by transferring the reinforcing inner frame 46 into the cavity of the thermoplastic elastomer injection mold and injection molding the floating support 44. It can also be manufactured by two-color molding instead of this manufacturing method. Thereafter, a predetermined key top 3 is bonded to each floating support portion 44, whereby the key sheet 41 of this embodiment is obtained.

  Therefore, the material used in the key sheet 11 of the first embodiment can be used for manufacturing the base sheet 42 and can be manufactured in the same manner as the key sheet 11.

5th Embodiment [FIG. 11, FIG. 12] ; The key sheet | seat 51 of this form adds the change to 4th Embodiment. In this embodiment, the base sheet 52 is composed of an elastic sheet 53 as a rubber-like elastic body. As shown in FIG. 12, the upper surface 53 a of the elastic sheet 53 is a flat surface having no unevenness, and can achieve weight reduction and thickness reduction by thinning at a fixing portion of the key top 3. In addition, a plurality of recesses 53 d are formed on the bottom surface 53 b of the elastic sheet 53 so as to project the pushers 53 c. The thickness of the rubber-like elastic body in the portion where the recess 53d is formed is thin, and this thin portion serves as a floating support portion 53e that supports each keytop 3 so as to be capable of being pressed and displaced.

  Each key top 3 is fixed to the thin floating support portion 53e with the bottom surface 3d floating from the top surface 53a by the adhesive portion 54 having a height. The bonding portion 54 is partially applied to the surface of the thin floating support portion 53e, not the entire surface thereof, and is cured. Thus, by setting the hardened region 53f (see FIG. 11) of the bonding portion 54 as an area smaller than the thin floating support portion 53e, the floating support portion 53e is elastically deformed in the outer region of the hardened region 53f. The key top 3 can be pressed and displaced. Therefore, unlike the floating support portions 15 and 44 of the above-described embodiments, it is not necessary to form a convex portion for fixing the key top 3 on the upper surface 53a of the elastic sheet 53. The sheet 53 can be reduced in thickness and weight can be reduced. Therefore, the key sheet 51 can be thinned.

  A thick portion 53g is formed on the outside of the concave portion 53d and the floating support portion 53e to surround them. The thick part 53g is thicker than the floating support part 53e, and supports the pusher 53c and the floating support part 53e. The thick portion 53g is provided with a reinforcing inner frame 53h as a “reinforcing member” made of a thin hard resin molded body. As shown in FIG. 1, the reinforcing inner frame 53h of the present embodiment is formed in a frame shape having an opening 53i so as not to interfere with the concave portion 53d and the floating support portion 53e.

  One of the methods for manufacturing the base sheet 52 as described above is integral molding by mold molding. In this case, the prepared reinforcing inner frame 53h is transferred in advance into the cavity of the molding die of the elastic sheet 53, and a rubber-like elastic body, that is, a thermosetting elastomer or a thermoplastic elastomer is molded. As a result, a molded body in which the reinforcing inner frame 53h is integrally molded with the rubber-like elastic body embedded therein, that is, the base sheet 52 is obtained. Thereafter, the base sheet 52 is removed from the molding die, and the key top 3 is fixed with an adhesive (adhesive portion 54), whereby the key sheet 51 is obtained. According to this manufacturing method, the elastic sheet 53 is firmly fixed to the reinforcing inner frame 53h. Therefore, if the rubber-like elastic body is not broken, the reinforcing inner frame 53h is not detached, and the base having excellent integrity is obtained. A sheet 52 is obtained.

  Accordingly, the base sheet 52 can be manufactured using the material used in the key sheet 11 of the first embodiment, and can be manufactured in the same manner as the key sheet 11.

  Further, in another method of manufacturing the base sheet 52, a reinforcing inner frame 53h that opens downward in a concave shape in the embedded portion of the reinforcing inner frame 53h in the thick portion 53g shown in FIG. 12 is formed by molding a rubber-like elastic body. A molded body molded as the mounting groove is obtained. Then, after removing from the molding die, a separately manufactured reinforcing inner frame 53h is fixed to the mounting groove with an adhesive (not shown). Thereby, the base sheet 52 to which the reinforcing inner frame 53h is fixed in the embedded state is obtained. Thereafter, when the key top 3 is fixed with an adhesive (adhesive portion 54), the key sheet 51 is obtained. According to this manufacturing method, since the reinforcing inner frame 53h is not used in the process of molding the rubber-like elastic body, the reinforcing inner frame 53h has low heat resistance, is likely to be thermally deformed, and is not familiar with mold molding. Even a material excellent in other required characteristics required for the key sheet 51 such as rigidity, durability, and transparency can be used.

Sixth Embodiment [FIGS. 13 and 14] ; The key sheet 61 of the sixth embodiment is a modification of the fifth embodiment. A different configuration from the fifth embodiment is that, as shown in FIG. 13, a reinforcing frame 63h is formed as a “reinforcing member” surrounding the floating support portion 63e located on the outer periphery. Therefore, since the reinforcing effect can be obtained around the outer edge of the base sheet 52, the overall rigidity can be further improved.

  Further, in the key sheet 61 of this embodiment, as shown in FIG. 14, the reinforcing frame 61 h is exposed on the upper surface 63 a of the elastic sheet 63 that forms the base sheet 62. According to this, for example, a transparent material is used as the key top 3, and the color of the reinforcing frame 63 h can be configured as a part of the design of the base sheet 62, and a key that can visually recognize an unprecedented design effect. A sheet 61 is obtained. Further, when the key sheet 61 is of an illumination type, specifically, the key top 3 is printed so that it can be illuminated in a letter shape, the base sheet 62 is made translucent, and the reinforcing frame 63h is colored with light shielding properties. Since the reinforcing frame 63h approaches the gap between the adjacent key tops 3, light leakage can be suppressed.

  The key sheet 61 of the sixth embodiment can also be manufactured by the same method using the same material as the key sheet 51 shown in the fifth embodiment.

Modification Examples of Embodiments ; Modification examples of each embodiment will be listed and described.

  In each of the above embodiments, the key top 3 may be made of a rubber-like elastic body such as a thermoplastic resin, a thermosetting resin, silicone rubber, or a thermoplastic elastomer. Further, since the base sheets 12, 22, 32, 42, 52, and 62 have high rigidity, heavy metal materials can be used. Moreover, about the key top 3, the display part which represents a character, a number, a symbol, etc. with ink, plating, etc. can be formed. Furthermore, the key top 3 can also be configured as a blank character illuminated key top or a character illuminated key top. Also, the three-dimensional shape of the key top 3 may be another three-dimensional shape. Of course, the base sheets 12, 22, 32, 42, 52, 62 may also have other shapes.

  In the above embodiment, the floating support portions 15, 44, 53e, and 63e are rectangular in plan view, but may be round, elliptical, or other polygonal shapes. Further, the shapes of the base sheets 12, 22, 32, 42, 52, and 62 may be other shapes regardless of the example of the embodiment.

  In the key sheet 31 of the third embodiment, the reinforcing layer 33 made of a thermoplastic elastomer that covers the front and back of the crosspieces 13a of the hard resin plate 13 is exemplified, but only one of the surfaces may be covered. Further, the reinforcing layer 33 may not partially cover all the crosspieces 13a but may partially cover them.

  In the key sheet 41 of the fourth embodiment, the reinforcing inner frame 46 is integrally molded with the hard resin plate 13 by molding, but may be bonded using an adhesive. Further, a reinforcing layer corresponding to the reinforcing inner frame 46 may be formed by applying and curing a liquid UV curable resin so as to correspond to the reinforcing inner frame 46.

  In the key sheet 41 of the fourth embodiment, the reinforcing inner frame 46 is illustrated as a single molded body corresponding to the shape of the crosspiece 13a of the hard resin plate 13, but this is divided into a plurality of molded bodies. Also good. Moreover, you may comprise as a single molded object including the reinforcement outer frame 23 of 2nd Embodiment, and conversely may not partially reinforce the crosspiece 13a.

  In the key sheet 41 of the fourth embodiment, a thermoplastic elastomer is exemplified as the elastic sheet 43, but an elastic sheet made of silicone rubber may be used. In this case, the reinforcing inner frame 46 and the reinforcing outer frame 23 can be fixed by bonding them with an adhesive or the like.

  Further, in the first and second embodiments, for example, as shown in FIG. 15A, a step portion 13b is formed on the crosspiece 13a, and a thermoplastic elastomer is fixed thereto, thereby increasing the fixing area and making it hard. The fixing force with respect to the resin plate 13 can be increased. Further, in the third embodiment, for example, as shown in FIG. 15B, a through hole 13c is formed in the crosspiece 13a, and a thermoplastic elastomer is poured and fixed therein, thereby increasing the fixing area. Due to the connecting structure in which the front and back are connected, the fixing force to the hard resin plate 13 can be increased.

  In the fifth embodiment, the reinforcing inner frame 53h is exposed on the bottom surface 53b of the elastic sheet 53. In the sixth embodiment, the reinforcing inner frame 53h is exposed on the upper surface 63a on the opposite side. However, as shown in FIG. You may make it embed completely. Further, as shown in FIG. 17, the reinforcing inner frame 53h may be formed at the boundary portion of the floating support portion 53e without forming the thick portion 53g between the adjacent floating support portions 53e. Further, as shown in FIG. 18, a reinforcing inner frame 53h is affixed to the bottom surface 53b serving as the sheet surface of the base sheet 53 with an adhesive, double-sided tape or the like (not shown), and the floating support portion 53e is used instead of the thick portion 53g. May be supported. Moreover, you may adhere to the upper surface 53a.

  The locations where the reinforcing inner frames 53h and 63h are formed in the base sheets 52 and 62 can also be changed according to the arrangement of the key tops 3. In short, if there are at least two key tops adjacent to each other in a narrow space, there is a need to reinforce with a “reinforcing member” such as a reinforcing inner frame 53h. Therefore, a “reinforcing member” may be provided between at least two floating support portions for fixing them.

  In the above embodiment, the key sheets 11 and 14 used for the mobile phone 1 are exemplified, but the present invention can be used for other devices such as a PDA and a remote controller.

  A key sheet (51) having the form shown in FIG. 12 was produced. A reinforcing inner frame (53h) as a reinforcing member is molded in advance with a polycarbonate resin having a deflection temperature under load including the structural unit represented by the above formula (2) of 180 ° C. Then, a rubber-like elastic body is used. The reinforcing inner frame (53h) was transferred into the cavity of the mold for forming the elastic sheet (53). Thereafter, silicone rubber as a rubber-like elastic body is injected into the cavity, and the silicone rubber is crosslinked (vulcanized) under conditions of 160 ° C. for 5 minutes, and a reinforcing inner frame (53h) in which the silicone rubber is made of polycarbonate resin. And a base sheet (52) integrated with was obtained. A key top (3) made of a polycarbonate resin separately molded from this and a urethane acrylate adhesive (54) were adhered by ultraviolet irradiation to obtain a key sheet (51) of the present invention. The key sheet (51) thus obtained was a key sheet (51) with good dimensional accuracy, with no deformation such as “sledge” in the base sheet (52).

  Further, as a material for the reinforcing inner frame (53h), the deflection temperature under load including the structural unit represented by the following formula (5) is 135 ° C. instead of the polycarbonate resin including the structural unit represented by the formula (2). A base sheet (52) integrated with silicone rubber was produced under the same conditions as above using a polycarbonate resin. The obtained base sheet (52) contained a slight “sledge”. For this reason, when this resin is used, a reinforcing inner frame (53h) deformed in advance in consideration of the occurrence of warpage is manufactured using a mold for manufacturing a reinforcing inner frame (53h) separately prepared for the resin. There was a need.

（式中、ｎは、４０〜１５０の範囲内にある整数）

(Where n is an integer in the range of 40 to 150)

1 Mobile phone (equipment)
DESCRIPTION OF SYMBOLS 1a Case 1b Operation opening 1c Back surface 1d Circuit board 1e Contact switch 11 Key sheet (1st Embodiment)
12 Base sheet 13 Hard resin plate (reinforcing member)
13a Crosspiece 13b Stepped portion 13c Through hole 14 Through hole 15 Floating support portion 16 Pusher 17 Flexible portion 21 Key sheet (second embodiment)
22 Base sheet 23 Reinforced outer frame (reinforcing member, pressure contact receiving part)
31 Key sheet (Third embodiment)
32 Base sheet 33 Reinforcing layer (reinforcing member)
41 Key sheet (fourth embodiment)
42 Base sheet 43 Elastic sheet 44 Floating support 46 Reinforcement inner frame (reinforcement member)
51 Key sheet (fifth embodiment)
52 Base sheet 53 Elastic sheet 53a Upper surface 53b Bottom surface 53c Pusher 53d Recessed portion 53e Floating support portion 53f Hardened region 53g Thick portion 53h Reinforcing inner frame (reinforcing member)
53i Opening 54 Adhesive 61 Key sheet (6th Embodiment)
62 Base sheet 63 Elastic sheet 63a Upper surface 63e Floating support part 63h Reinforcement frame (reinforcement member)

Claims (6)

In a key sheet comprising: a base sheet that is pressed and held in the casing of the device at the outer edge side; and a plurality of key tops that are arranged on the base sheet and exposed from an operation opening without a partition rail formed in the casing ,
The base sheet includes a plurality of floating support portions made of a rubber-like elastic body that fixes the key top, and a thin plate-like reinforcing member made of a hard resin that supports the floating support portion so that it can be pressed and displaced.
A key sheet characterized in that a reinforcing member is provided on a crosspiece that separates the floating support portions inside the outer edge side portion, and the crosspiece is configured not to be constrained to the casing and the circuit board.   The key sheet according to claim 1, wherein the reinforcing member is formed in a lattice shape for partitioning only between adjacent floating support portions.   The key sheet according to claim 1 or 2, wherein a pressure contact receiving portion made of a rubber-like elastic body is provided on an outer edge side portion of the base sheet, and the pressure contact receiving portion is pressed and held in the housing. The housing of the device,
A circuit board;
A key sheet having a base sheet pressed and held in the casing of the device at the outer edge side, and a plurality of key tops disposed on the base sheet and exposed from an operation opening without a partition rail formed in the casing; In the key seat mounting structure comprising:
The base sheet includes a plurality of floating support portions made of a rubber-like elastic body that fixes the key top, and a thin plate-like reinforcing member made of a hard resin that supports the floating support portion so that it can be pressed and displaced.
A reinforcing member is provided on a crosspiece that separates the floating support portions inside the outer edge side portion, and the crosspiece is configured not to be constrained to the casing and the circuit board. Mounting structure.   The key sheet mounting structure according to claim 4, wherein the reinforcing member is formed in a lattice shape for partitioning only between adjacent floating support portions.   6. The key sheet mounting structure according to claim 4, wherein a pressure contact receiving portion made of a rubber-like elastic body is provided on an outer edge side portion of the base sheet, and the pressure contact receiving portion holds the pressure contact inside the casing.

Images