WO2011081148A1

WO2011081148A1 - Key-top structure, electronic device, and method of manufacturing key-top structure

Info

Publication number: WO2011081148A1
Application number: PCT/JP2010/073598
Authority: WO
Inventors: 昌秀高橋; 隆男清水; 均安藤
Original assignee: 信越ポリマー株式会社
Priority date: 2009-12-28
Filing date: 2010-12-27
Publication date: 2011-07-07
Also published as: JP5330220B2; JP2011138702A; CN102714105A; KR20120106831A; KR101347426B1; CN102714105B

Abstract

Disclosed is a key-top structure, an electronic device, and a method of manufacturing the key-top structure, wherein a clicking feeling upon pushing-in the key-top structure is excellent, or wherein deformation of a key-top member that takes place when manufacturing the key-top member by hardening ultraviolet-curing resin can be alleviated. The key-top structure (60) is provided with: the key-top member (61), wherein a sheet-formed section (61b) and a plurality of key-tops (61a) are formed by hardening ultraviolet curing resin, the key-tops (61a) are made to have a greater thickness dimension (T) than the sheet-formed section (61b), and a section exists therein where the plurality of key-tops (61a) are arranged in row-form with a prescribed gap given therebetween; and a deformation alleviating means for alleviating deformation due to contraction of the key-top member (61) after the hardening thereof, when forming the key-top member (61) by hardening ultraviolet curing resin onto a base material.

Description

KEYTOP STRUCTURE, ELECTRONIC DEVICE, AND KEYTOP STRUCTURE MANUFACTURING METHOD

The present invention relates to a key top structure, an electronic device, and a method for manufacturing the key top structure.

A key top structure used for electronic devices such as mobile phones is generally formed by applying ink to a resin molded product and / or decorating such as character printing, and then forming a series of key top structures. For this purpose, many techniques for bonding and arranging on a polyethylene terephthalate (PET) film or silicone rubber, which is a flexible substrate, are used. Recently, for the purpose of responding to the demand for thinning mainly for portable terminals such as mobile phones, an ultraviolet curable resin is molded on a film-like base material, and on the back surface of the film-like base material. A key top structure with printing and / or decoration is used.

As a technique for manufacturing such a key top structure, there is one disclosed in Patent Document 1.

JP 2009-135083 A

By the way, the key top portion is formed on the front surface side (top surface side) of the base material by the method disclosed in the above-mentioned Patent Document 1, and the colored layer is further formed on the back surface side of the base material. When used as a key top structure of a member, there are the following problems.

First, since the base material is made of polyethylene terephthalate (PET) or the like formed by biaxial stretching, the stretchability is not excellent. Therefore, when the user presses the key top structure, the click feeling is not excellent (first problem).

Further, when the key top structure is formed on the surface of the base material by the technique disclosed in Patent Document 1, the surface side (the top side) is caused by shrinkage when the key top member is produced by curing the ultraviolet curable resin. The key top structure is deformed so that the surface side is concave (the key top structure is warped; the second problem). Here, in order to suppress such deformation, it is conceivable to adopt a method of increasing the thickness dimension of the base material. However, even when the thickness dimension of the base material is increased, there is generally a portion that cannot be fixed with the fixing tape at the end of the base material due to the offset of the fixing tape (double-sided tape) or the like. For this reason, local deformation (local deformation) occurs at the end portion of the base material, and it is possible to feel a sense of catching due to local deformation, for example, by touching the keys when operating the keys. Here, when an unexpected peeling force is applied to the end portion where the feeling of catching is applied, there is a possibility that the ultraviolet curable resin may peel from the base material.

Also, when the base material is thickened, the base material is not easily deformed even when the key top portion is pushed in, and is not suitable as a key top structure.

The present invention has been made based on the above circumstances, and its object is to solve at least one of the first problem and the second problem, when the key top structure is pushed in. Providing a key top structure, an electronic device, and a method for manufacturing the key top structure that have excellent click feeling or that can suppress deformation of the key top member when the key top member is produced by curing an ultraviolet curable resin. It is what.

In order to solve the above-mentioned problem, the first side surface of the key top structure of the present invention is to inject a liquid ultraviolet curable resin into the concave portion of the molding die and cover the ultraviolet curable resin injected into the concave portion, In addition, the substrate is positioned in close contact with the UV curable resin, and the UV curable resin is irradiated with ultraviolet rays to cure the UV curable resin. By removing the unitary member, and then peeling the substrate from the unitary member of the base material and the key top member, the sheet-like portions are arranged in rows at predetermined intervals and the thickness dimension is larger than the sheet-like portion. A large key top member is formed and has this key top member.

In such a configuration, the ultraviolet curable resin shrinks upon curing, but by peeling the base material from the integral body, it becomes possible to suppress deformation due to shrinkage after the key top member is cured. Therefore, it is possible to suppress deformation so that the surface side (top surface side) of the key top member is concave. In addition, by peeling off the base material, it is possible to eliminate local deformation that occurs at the end of the key top base material.For example, even when touching when operating a key, it is possible to prevent the user from feeling caught by local deformation. Become. Here, when a feeling of catching due to local deformation is felt, if an unexpected peeling force is applied to the end where the feeling of catching is applied, the key top member may be peeled off from the base material. Then, it is possible to eliminate such a problem by peeling off the base material.

In another aspect of the key top structure of the present invention, in the above-described invention, at least one side of the portion corresponding to the key top in the liquid ultraviolet curable resin is located closer to the center than the end of the side. However, the key top member that protrudes from the inside of the key top is protruded to the side away from the inside of the key top. It is preferable that it is linear.

In the case of such a configuration, at least one side of the key top can maintain a linear shape in the curing shrinkage of the uncured ultraviolet curable resin. Therefore, it is possible to realize a key top that is less affected by curing shrinkage.

Further, according to another aspect of the key top structure of the present invention, a sheet-like portion and a plurality of key tops are formed by curing an ultraviolet curable resin, and the key top has a thickness dimension larger than that of the sheet-like portion. A key top member having a portion in which a plurality of key tops are arranged in a row with a predetermined interval is formed, and an ultraviolet curable resin is cured on the base material to form the key top member. In this case, deformation suppression means for suppressing deformation due to shrinkage of the key top member after curing is provided.

In such a configuration, the ultraviolet curable resin shrinks upon curing, but the presence of the deformation suppressing means can suppress deformation due to shrinkage after curing of the key top member. For this reason, it is possible to prevent the key top structure from being deformed so that the surface side (the top surface side) is concave.

According to another aspect of the key top structure of the present invention, in the above-described invention, the deformation suppressing means peels the base material from the key top member after the shrinkage after curing of the key top member is within a predetermined range. It is preferable that it is comprised.

When configured in this way, the deformation suppressing means is configured by peeling the base material from the key top member after the shrinkage after curing falls within a predetermined range, so the key top member has excellent stretchability. No base material is in a non-bonded state. Therefore, when the user presses the key top structure, it is possible to eliminate a state where the click feeling is not excellent.

Furthermore, in another aspect of the key top structure of the present invention, in the above-described invention, the thickness of the sheet-like portion is in the range of 0.03 mm to 0.15 mm, and a predetermined interval between the plurality of key tops The interval is preferably 0.2 mm to 1.0 mm.

When configured in this way, deformation due to shrinkage after hardening of the key top member can be further suppressed, and when the user pushes the key top structure, it should have excellent click feeling. Can do.

Further, according to another aspect of the key top structure of the present invention, a sheet-like portion and a plurality of key tops are formed by curing an ultraviolet curable resin, and the key top has a thickness dimension larger than that of the sheet-like portion. And a key top member having a portion in which a plurality of key tops are arranged in a row with a predetermined interval, and the thickness dimension of the sheet-like portion is in the range of 0.03 mm to 0.15 mm The predetermined distance between the plurality of key tops is preferably in the range of 0.2 mm to 1.0 mm.

In another aspect of the key top structure of the present invention, in the above-described invention, it is preferable that the key top member has a Shore D hardness within a range of 40 degrees to 80 degrees.

Furthermore, in another aspect of the key top structure of the present invention, in the above-described invention, when any key top is pushed in from the top surface side, the key top member is only a pushing object of the pushed key top. It is preferable to include a deformation allowing means for pressing the key and independently pressing the key top other than the pressed key top so that the key top does not press the object to be pressed.

In the case of such a configuration, since the deformation permitting means is provided, it is possible to reliably push only the pushing object corresponding to the pushed key top. For this reason, when the key top structure is used in an electronic device, it is possible to prevent a malfunction during pressing.

In addition, the electronic device of the present invention includes each of the above-described key top structure inventions, and has an installation site for installing the key top member, and the installation site is in direct contact with or indirectly from the key top member. It is preferable that it becomes a part of the component of a deformation | transformation suppression means by contacting regularly.

In the case of such a configuration, the installation site can directly or indirectly contact the key top member, thereby further suppressing deformation due to shrinkage after the key top member is cured. For this reason, it is possible to further favorably suppress deformation so that the surface side (top surface side) of the key top structure becomes concave.

Furthermore, the key top structure manufacturing method according to another aspect of the present invention includes an injection step of injecting a liquid ultraviolet curable resin into the concave portion of the molding die, and covering the ultraviolet curable resin injected into the concave portion, In addition, an installation step of positioning the base material in close contact with the ultraviolet curable resin and irradiation of the liquid ultraviolet curable resin with ultraviolet rays to cure the ultraviolet curable resin to produce a key top member. It is preferable to include a curing step, a removing step of removing the integrated body of the base material and the key top member from the molding die, and a peeling step of peeling the base material from the integrated body of the base material and the key top member.

In such a configuration, the ultraviolet curable resin shrinks upon curing, but the presence of the peeling step can suppress deformation due to shrinkage after curing of the key top member. For this reason, it is possible to prevent the key top structure from being deformed so that the surface side (the top surface side) is concave.

According to the present invention, when the key top structure is pushed in, the click feeling can be excellent. Alternatively, when the key top member is produced by curing the ultraviolet curable resin, deformation of the key top member can be suppressed.

It is a perspective view which shows the structure of the portable terminal which concerns on one embodiment of this invention. FIG. 2 is a cross-sectional view showing a configuration of a key arrangement portion and a key top structure, and a part along the line AA of FIG. It is a flowchart for demonstrating the manufacturing method of a keytop structure. It is a schematic diagram for demonstrating the manufacturing method of a keytop structure using a shaping die. In an uncured key top member, it is a top view showing the state where the size of the transversal direction along the end of a longitudinal direction was made larger than the size of the transversal direction along the center of a longitudinal direction. In the uncured key top member, in addition to the state of FIG. 5, a plan view showing a state in which the longitudinal dimension along the end in the lateral direction is larger than the longitudinal dimension along the center in the lateral direction. It is. It is a figure which shows the hardening shrinkage | contraction of a key top, (A) shows what match | combined the state before hardening with the prescription | regulation dimension, (B) has shown what adjusted the state after hardening to the prescription | regulation dimension. . It is a figure which shows the relationship between the space | interval of adjacent key tops, and the load required when pushing in a key top. It is a side view which shows the state which the local deformation | transformation has produced in the key top structure, (A) shows the whole structure, (B) is a figure which expands and shows A part. It is sectional drawing which shows the state by which the base material has not been peeled from the keytop member. It is sectional drawing which shows the state which concerns on the modification of this Embodiment, and the base material was curved so that the top | upper surface side of a keytop structure might warp. It is a perspective view which shows the structure of the mobile telephone apparatus which concerns on the modification of this invention.

Hereinafter, a key top structure 60 and an electronic apparatus using the key top structure 60 according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a mobile terminal 10 that can be used as a mobile phone device, a mail terminal, or the like will be described as an example of an electronic device. However, the electronic device is not limited to the mobile terminal 10. As long as it has the key top structure 60, it may be anything.

<Overall configuration of mobile phone device>
As shown in FIG. 1, the mobile terminal 10 in the present embodiment includes a housing unit 20, a display unit 30, a cursor key unit 40, and a key arrangement unit 50. 1 and the following description, the longitudinal direction of the mobile terminal 10 is described as the X direction, the short direction of the mobile terminal 10 is defined as the Y direction, and the thickness direction of the mobile terminal 10 is described as the Z direction.

The housing unit 20 is a part that covers the internal configuration of the mobile terminal 10 and protects the internal configuration from external impacts, dust, and the like. The housing 20 is appropriately provided with an opening or a recess, and a display 30 is provided in one of the openings or the recess. The display unit 30 includes, for example, an organic EL (electroluminescence) display, a liquid crystal display, and the like, and an image is expressed as a collection of pixels having a predetermined gradation of RGB based on a display driver of a control unit (not shown). .

As shown in FIG. 1, the cursor key unit 40 includes an annular button unit 41 and a center button unit 42, and the cursor key unit 40 and the annular button unit 41 are provided on the housing unit 20. The top surface side of the key top 61a (see FIG. 2) protrudes from the opening. Among these, the annular button portion 41 has a portion to be pressed at intervals of 90 degrees, for example. Further, the center button portion 42 is a portion where a portion to be pressed (the top surface side of the key top 61 a) is surrounded by the annular button portion 41.

In FIG. 1, a total of four key portions provided side by side in the X direction with respect to the cursor key portion 40 may be included in the cursor key portion 40, and It may be included.

Further, in the key arrangement portion 50, the top surface side of the key top 61a protrudes from the opening of the housing portion 20 in the same manner as the cursor key portion 40. As shown in FIG. 1, in this key arrangement portion 50, three key tops 61a having the same shape are arranged side by side in the Y direction, for example, and the total number of key tops 61a is 32. The number of key tops 61a is not limited to 32, and any number may be provided. Typical numbers of key tops 61a include, for example, between 15 and 19, and between 30 and 50.

In the key arrangement unit 50 shown in FIG. 1, the arrangement of the key tops 61 on the left side and the back side when the user inputs is in the order of QWERTY, and hence is called a QWERTY keyboard arrangement. It is. Such a key arrangement is also adopted in the mobile terminal 10 as shown in FIG. 1 when 30 or more key tops 61 are arranged. In addition, the key arrangement | positioning part 50 is good also as an arrangement | sequence with which the key tops 61 are arranged not only in the orthogonal | lattice grid | lattice form (grid-like shape) arrangement | sequence as shown in FIG.

The key arrangement structure 50 of the present embodiment as shown in FIG. 2 is embodied in the key arrangement unit 50 described above. However, the key top structure 60 may be configured to be embodied in the cursor key unit 40, or may be configured to embody the key top structure 60 in both the key arrangement unit 50 and the cursor key unit 40. In addition, in the mobile terminal 10, an installation site where the key top structure 60 is installed is present inside the housing unit 20. This installation site can also be a part of the constituent elements of the deformation suppressing means described later by directly contacting or indirectly contacting the key top member 61 described later.

The cursor key unit 40 and the key arrangement unit 50 electrically connect a fixed contact 72 and a disc spring-like member 73, which will be described later, when the user presses the top surface of the key top 61a with a finger or the like. It is possible to contact. A control unit (not shown) can execute a predetermined function corresponding to the pressing.

<Details of key top structure>
Next, details of the key top structure 60 will be described. In the following description, as an example of the key top structure 60, the key top structure embodied in the key arrangement unit 50 will be described including the details of the configuration of the key arrangement unit 50. Further, the details of the configuration of the cursor key unit 40 are the same as the configuration of the key arrangement unit 50, and thus the description thereof is omitted.

The key arrangement unit 50 includes a key top member 61, a colored layer 62, a presser 70, and a substrate 71.

Among these, the key top member 61 constitutes the key top structure 60 together with the colored layer 62. As will be described later, the key top member 61 is formed by curing an ultraviolet curable resin by ultraviolet irradiation. Here, as a liquid ultraviolet curable resin, what added the photoinitiator etc. to the main ingredient containing a photopolymerization type prepolymer and a monomer can be used. Further, as the ultraviolet curable resin, in addition to the above, a filler, an antioxidant, a reaction accelerator, a reaction inhibitor, a stabilizer, a colorant, and the like may be blended as necessary. As the main component of the ultraviolet curable resin, monomers and / or oligomers such as acrylic, methacrylic, styrene, unsaturated polyester, polyester polyol, polyester ether, urethane, silicon, epoxy or phenol, Monomers and / or oligomers of these derivatives, or a mixture of a plurality of these can be used.

Further, as the ultraviolet curable resin, a resin having a small curing shrinkage, transparent, and excellent in heat resistance, environment resistance, colorability, and moldability is desirable. Specifically, acrylic, methacrylic, allyl, It is desirable to use urethane-based, unsaturated polyester-based, silicon-based materials, or derivatives or mixtures thereof.

Here, when the cured resin is formed by curing the ultraviolet curable resin, the thickness of the cured resin is more suitable when the thickness dimension is 0.3 mm or less or smaller than 0.3 mm. Yes. On the other hand, when a resin cured product of a resin such as polycarbonate is formed by injection molding, the thickness of the resin cured product is more suitable when it is 0.5 mm or more or larger than 0.5 mm. When the thickness dimension of the cured resin is 0.3 mm or more or larger than 0.3 mm and smaller than 0.5 mm or smaller than 0.5 mm, the cured resin is formed by curing the ultraviolet curable resin. Alternatively, a cured resin product may be formed by injection molding.

The key top member 61 formed by curing the ultraviolet curable resin preferably has a Shore D hardness in the range of 40 degrees to 80 degrees.

The key top member 61 has a key top 61a and a sheet-like portion 61b. The key top 61a is a portion provided thicker than other portions (the sheet-like portion 61b in FIG. 2) of the key top member 61.

Further, the thickness dimension S of the sheet-like portion 61b is preferably in the range of 0.03 mm to 0.15 mm. When the thickness dimension is smaller than 0.03 mm, the sheet-like portion 61b is often damaged, and when the thickness dimension S is larger than 0.15 mm, the deformation flexibility of the sheet-like portion 61b is increased. It is because it is damaged. Further, within the above range, it is more preferable to be in the range of 0.03 mm to 0.10 mm, and it is even more preferable to be in the range of 0.03 mm to 0.05 mm.

Furthermore, the distance L between the key tops 61a is preferably in the range of 0.2 mm to 1.0 mm. In particular, by setting the interval L to a value within such a range, it is possible to arrange a large number of key tops 61 while increasing the area of the key tops 61 and ensuring good pressability with fingers. Yes.

Further, a colored layer 62 is formed on the back surface side (Z2 side in FIG. 2) of the key top member 61. In addition, it is good also as the key top structure 60 that this colored layer 62 does not exist.

Further, the presser 70 (indicated by a broken line in FIG. 2) is provided so as to protrude toward the substrate 71 from the back surface side of the colored layer 62. The pressing element 70 is formed integrally with an elastic sheet, for example, and may be formed by adhering the elastic sheet to the back surface side of the colored layer 62. Further, a protrusion that becomes the pressing element 70 is formed. Alternatively, it may be formed by bonding to the back side of the colored layer 62. Further, the key top structure 60 may not include the pressing element 70 or may include the pressing element 70.

Further, a substrate 71 is provided in a state of facing the key top structure 60.

Fixed contacts

72 a and 72 b and a disc spring-like member 73 are provided on the surface of the substrate 71 facing the key top structure 60. The fixed

contacts

72 a and 72 b are a part of conductive parts formed on the substrate 71. The disc spring-like member 73 corresponds to an example of an object to be pushed in the claims. The disk spring-like member 73 has a shape in which the cup shape is reversed in appearance, and the edge of the disk spring-like member 73 is in contact with at least a part of the fixed contact 72a on the substrate. . The disc spring-like member 73 is provided so as to be capable of buckling (plane buckling). Therefore, when the user presses the key top 61a and a pressing force of a predetermined level or more is applied to the disc spring-like member 73, a part of the disc spring-like member 73 is recessed from the state of projecting in the Z1 direction. It transforms into a state to do. At this time, a part of the disc spring-like member 73 comes into contact with the fixed contact 72b, and a state where electrical conduction is possible occurs.

When the key top 61a is released, the buckled state disappears due to the elasticity of the disc spring-like member 73 and returns to the original state. As a result, the disc spring-like member 73 and the fixed contact 72 are not in contact with each other and are electrically non-conductive.

<About manufacturing method of key top structure>
Then, the manufacturing method of the key top structure 60 based on this Embodiment is demonstrated. FIG. 3 is a flowchart for explaining the outline of the manufacturing method of the key top structure 60. FIG. 4 is a schematic diagram for explaining the manufacturing method of the key top structure 60 with the molding die 101 as the center.

When manufacturing the key top structure 60, first, the liquid ultraviolet curable resin M is filled into the molding die 101 from a pressurized tank (not shown) (S01; see FIG. 4A).

Subsequently, the feed roller 102 on which the base material 110 is stretched is positioned on one end side of the molding die 101 (left side in FIG. 4B) (S02). After that state, the feed roller 102 is moved from one end side to the other end side (right side in FIG. 4C) (S03). Then, as shown in FIG. 4 (c), the ultraviolet curable resin M whose upper surface is not flat is pushed out, and the upper surface of the ultraviolet curable resin M is flat so as to follow the substrate 110. It becomes. And the base material 110 is located in the state which covers the recessed part 103 on the upper surface side of the ultraviolet curable resin M. FIG.

Here, in the present embodiment, as shown in FIG. 5, when the uncured key top member 61 (ultraviolet curable resin M) is viewed in plan, the key top member 61 (ultraviolet curable resin M) As for the dimension in the short direction, the dimension X2 in the short direction along the end in the longitudinal direction is smaller than the dimension X1 in the short direction along the center in the long direction. This is because the shrinkage at the time of curing occurs more at the ends in the longitudinal direction. Therefore, in the cured key top member 61, the above-described dimension X1 = the above-mentioned dimension X2. Note that such equations may contain some errors.

If the idea shown in FIG. 5 is further developed, the state shown in FIG. 6 is obtained. As shown in FIG. 6, when the uncured key top member 61 (ultraviolet curable resin M) is viewed in plan, the dimension of the key top member 61 (ultraviolet curable resin M) in the longitudinal direction is the short direction. The dimension Y2 in the longitudinal direction along the end in the short direction is smaller than the dimension Y1 in the longitudinal direction along the center of the center. If it does in this way, in the key top member 61 after hardening, it will be the above-mentioned dimension Y1 = the above-mentioned dimension Y2. Note that such equations may contain some errors.

Further, shrinkage when the uncured key top member 61 (ultraviolet curable resin M) is cured also occurs in the key top 61. That is, when the state before curing is adjusted to a specified dimension without considering curing shrinkage, as shown in FIG. 7A, the end portions of the sides of the key top 61 are cured by the curing of the ultraviolet curable resin M. The region closer to the center contracts to dent inward. For this reason, in the case shown in FIG. 7B, in consideration of such curing shrinkage, when the ultraviolet curable resin M is in an uncured state, the portion closer to the center than the end of each side of the key top 61 is outside ( It protrudes to the side away from the inside of the key top 61. That is, the concave portion 103 of the molding die 101 is set in a state in which the left key top 61 in FIG. Then, as shown on the right side of FIG. 7B, a key top 61 having a prescribed size is formed by curing shrinkage.

Subsequently, ultraviolet irradiation is performed by bringing the ultraviolet irradiation device 105 close to the molding die 101 (S04; see FIG. 4 (d)). When the ultraviolet ray is irradiated for a predetermined time, the ultraviolet curable resin M is cured. After the ultraviolet irradiation is completed, the ultraviolet irradiation device 105 is retracted upward. Then, the solidified portion as the key top member 61 is peeled off from the molding die in a state of being attached to the base 110 (S05).

After this, the part where the key top member 61 is adhered to the base material 110 is taken out, and the base material is peeled off from the key top member 61 (S06). Here, in order to make it easy to peel the base material 110 from the key top member 61, a predetermined chemical may be applied to the base material. Moreover, as a timing which peels the base material 110 from the keytop member 61, for example, immediately after the ultraviolet irradiation by the ultraviolet irradiation device 105 is performed is desirable.

The key top member 61 is manufactured as described above. Thereafter, the colored layer 62 may be formed on the back surface of the key top member 61 by, for example, decorative printing. Moreover, you may make it perform the heat processing (heating process) for hardening the key top member 61 manufactured as mentioned above.

<< Up to the realization of the key top structure in the present embodiment >>
[1. Necessity of UV curable resin]
When the key top structure is formed by injection molding, the resin is poured into a mold and cured, but due to restrictions on the molding, for example, it is difficult to mold the key top with a thickness dimension of 0.3 mm or less. There are restrictions on molding. In addition, in the key top member, it is difficult to mold a shape in which a large number of key tops are continuous due to the design restrictions of the parts for pouring resin such as the injection port in the mold and the flow path thereafter. It is necessary to form a key top that is shaped and then to separate and further assemble the key top.

Compared with such injection molding, it is possible to form a molded product using an ultraviolet curable resin in which a large number of key tops are continuous. However, in the case where a large number of key tops are continuous, it is difficult to have a certain thickness as a key top because problems such as bubble entrapment and sink marks occur. In other words, when producing a molded product using an ultraviolet curable resin, it is difficult to produce a molded product having a large thickness, but conversely, in recent years, there has been a need for thinning (when producing a molded product having a small thickness). It can be said that it is very suitable.

Also, when the top surface of the key top is increased in order to make the key top structure easy to operate, the distance between the key tops decreases as a contradiction. If the distance between the key tops is small, interference may occur between adjacent key tops, which may impair the operational feeling. Here, the relationship between the space | interval of adjacent keytops and the load required when pushing in a keytop is shown in FIG. As can be seen from FIG. 8, when the distance between the adjacent key tops is increased, it can be said that the load during pressing is small and the operational feeling is good.

In addition, in order to reduce the interval between adjacent key tops and improve the operational feeling when the key tops are pushed in, all the key tops are cut off and placed on a sheet-like member having a high elastic modulus. It is also conceivable to adopt a method of attaching by attaching or the like at a pitch of.

That is, in order to improve the feeling of pressing at the time of operation, it is necessary to transmit the change in load when pressing the disc spring-like member below the key top to the key top without loss. However, in the key top structure in which the key tops are continuous, as the pressed key top is deformed, the adjacent key tops are also continuously deformed with respect to the pressed key top. Therefore, the load required for such deformation is the sum of the loads required for these deformations plus the load required when pressing the disc spring member, and the pressing feeling during operation deteriorates. In order to avoid such deterioration of the pressing feeling, as described above, it is necessary to separate all the key tops molded with the ultraviolet curable resin so as to be independent and attach them to a sheet-like member having a low elastic modulus by adhesion or the like. .

However, in this case, there is a problem that the man-hours for manufacturing are complicated and the man-hours are increased. In addition, there is a problem that it is difficult to form a constant key top interval. In some cases, an installation error such as an incorrect key top interval may occur. For this reason, it is difficult to adopt a method of separating the molded key tops so as to be independent and attaching them to a sheet-like member having a high elastic modulus by adhesion or the like.

[3. About UV curable resin and substrate]
By the way, at present, when a molded product as a key top member is produced using an ultraviolet curable resin, it is necessary that the base material and the key top member are bonded. As described in the manufacturing method described above, this is because the film-like base material is positioned on the upper part of the mold where the depression of the key top member exists, and the amount of resin of the required key top member is larger than that. Fill with a large amount of liquid UV curable resin, and then move it while bringing the squeegee into contact with the film-like base material, and push out the excess liquid UV curable resin at the part on the back side of the key top member. In this way, the molded product that has been shaped and then cured and solidified as a key top member is taken out from the molding die.

Since the key top member is formed in this manner, the molded product of the ultraviolet curable resin and the base material are bonded or in a strong adhesive state. Therefore, in order to improve the feeling of pressing during the operation as described above, it is necessary to minimize the thickness dimension of the base material or to use a flexible material as the base material. However, when the thickness dimension of the base material is minimized, and when a flexible material is used as the base material, there is a problem that warpage increases.

[4. Experimental results of key top structure with base material]
Table 1 shows the experimental results of measuring the load required for pressing and the click feeling when the thickness dimension of the base material was changed between 0.05 mm and 0.15 mm. Here, the click rate (%), which is an index value indicating the click feeling, is a value (%) defined by the following equation when the same disc spring-like member is used. C represents the click rate (%), P represents the peak load (unit: grams), and B represents the bottom load (unit: grams). The peak load indicates the maximum load before the disc spring-like member buckles, and the bottom load indicates the minimum load that can maintain the buckled state after the disc spring-like member buckles. The material of the base material at this time is polyethylene terephthalate (PET).
C = 100 × (P−B) / P

Further, when the thickness dimension of the base material changes as in Table 1 above, the warp size of the key top structure at each thickness dimension, whether the warp can be corrected by the double-sided tape, and Table 2 shows the experimental results of measuring the feeling of catching at the end. Note that the warp of the key top structure referred to here is the end on the back side of the key top structure with respect to the reference surface when the center portion on the back surface of the key top structure is in contact with the reference surface. Refers to the raised height. In addition, the feeling of catching at the end of the key top structure means that the end of the key top structure has a larger curvature than the above-mentioned warp, and local deformation occurs in the same direction as the warp. It feels like it gets caught in the hand when you touch the end of the hand. In Table 2, the experiment was conducted using a key top structure having a length dimension from one end to the other end of 50 mm.

In addition, when the thickness dimension of the base material changes as in Table 1 above, the load required for pressing when the base material material (material) is changed, and the experimental results measured for the click feeling, Table 3 shows. In Table 3, the thickness dimension of each base material is 0.1 mm.

Here, although both the material and the thickness dimension are different, an example of a load and a click rate that are more preferable than those in Table 3 will be described. The load of a key top that was cut in advance on a base material having a thickness of 0.2 mm and made of silicone rubber was 234 g, and the click rate was 27%.

[5. Consideration from experimental results of key top structure with base material]
According to the above experimental results in Tables 1 to 3, when the thickness dimension of the substrate was 0.05 mm, a relatively good click feeling (operation feeling) could be obtained. On the other hand, as the thickness dimension of the base material increases from 0.1 mm to 0.125 mm, the click feeling (operation feeling) deteriorates. In particular, in a base material having a thickness dimension of 0.125 mm or more, the total load required at the time of clicking is increased until the change in load on the disc spring-like member is not felt so much.

Further, according to the above experimental results, when the thickness dimension of the base material is 0.05 mm, a large warp occurs in the key top structure, while when the thickness dimension of the base material is 0.125 mm, the key top The warpage in the structure can be suppressed to about 1.5 mm.

From this result, when the thickness dimension of the base material is 0.05 mm, the warp of the key top structure is large, but the base material itself is thin, so that there is no so-called waist. By sandwiching, correction is easily possible. On the other hand, when the thickness dimension of the substrate is 0.125 mm, there is little warpage in the key top structure, and fixing with a double-sided tape is also possible. Therefore, it seems to be good at first glance. However, as shown in FIG. 9, at the end of the key top structure, the double-sided tape is offset with respect to the base material or the like, so that a portion that cannot be fixed by the double-sided tape occurs. Here, it is not possible to attach the double-sided tape so that it protrudes from the key top structure due to dimensional restrictions on the base, which is the attachment site of the key top structure, problems in appearance, and the like. Therefore, a portion where the double-sided tape is offset with respect to the base material or the like is generated at the end of the key top structure.

Further, since local deformation occurs in this portion, a feeling of catching will be felt even when touching, for example, when operating a key. Moreover, since heat is generated from the circuit or the like inside the mobile terminal 10, the above-described local deformation is spurred. In addition, when an unexpected peeling force is applied to an end portion where a feeling of catching is applied, there is a possibility that the key top structure is peeled from the casing.

In addition, the double-sided tape is attached to the end portion and the back side of the base material in a state of surrounding shape, and is fixed to a predetermined fixing portion via the double-sided tape.

As described above, even if the overall warping of the key top structure can be reduced by adopting the technique of increasing the thickness dimension of the base material, The experimental results revealed that the feeling of catching cannot be resolved. In addition, it is necessary to consider that there is a demand for a thin keytop structure in an actual machine. As described above, it is very difficult to eliminate the feeling of catching at the end of the key top structure within the framework of conventional methods and ideas.

Here, when touching on the cause of warping, in the key top structure, curing shrinkage occurs in the process of curing the uncured ultraviolet curable resin. For example, as a widely used ultraviolet curable resin, in the case of a radical polymerization type ultraviolet curable resin having acrylate and unsaturated polyester as main components, curing shrinkage of about 5 to 10% occurs. On the other hand, the substrate is not excellent in stretchability. Therefore, if the ultraviolet curable resin is located on the surface side of the base material, the deformation is such that the surface side where the ultraviolet curable resin is located becomes concave as the ultraviolet curable resin is cured and contracted. Occurs.

[6. Trial of new method]
Therefore, we searched for a method that changed the way of thinking from the conventional method and took a completely different approach. In this search, it was considered to adopt a method in which the thickness of the base material is theoretically the smallest and the base material is eliminated. In the current situation, the fact that others have adopted this approach in the key top structure has not been confirmed. This is because, in the production of a molded product using the current ultraviolet curable resin, in addition to the presence of a base material is essential for the curing of the ultraviolet curable resin due to the fact that the reference site is not determined. As can be seen from Table 2 above, since the warp can be reduced to some extent by taking the approach of increasing the thickness dimension of the base material, there is a possibility of being bound by the idea of increasing the thickness dimension of the base material. It seems to be because there is.

In addition, as described above, in the production of a molded product using the current ultraviolet curable resin, since the presence of the base material is indispensable, if the base material is lost when using the ultraviolet curable resin, Molding as a key top member becomes difficult. Therefore, further ingenuity is required, but after various investigations, until the ultraviolet curable resin is cured, the ultraviolet curable resin is bonded to the base material, and the ultraviolet curable resin is cured. Later, the method of peeling the substrate was led, and the details of the method were examined.

[7. Examination of new method from thickness dimension]
In this study, the thickness of the sheet-like portion of the key top member, which is a molded product of an ultraviolet curable resin, is changed between 0.03 mm and 0.15 mm, and the load required for pressing at each thickness dimension, Table 4 shows the experimental results measured for the click feeling. In this experiment, H17 (trade name) manufactured by Nogawa Chemical and having a Shore D hardness of 50 degrees is used as the material of the ultraviolet curable resin.

Comparing the experimental results in Table 4 and the experimental results in Table 1 above, the following can be said. That is, when the method of peeling the substrate after the ultraviolet curable resin is cured is adopted, the total load is greatly reduced and the click feeling (operation feeling) is also greatly improved. Furthermore, in the key top member, warpage and local deformation were hardly observed. Here, since the ultraviolet curable resin is formed of a material having sufficiently higher flexibility than the base material, it is possible to realize a state in which warpage and local deformation do not become a problem.

[8. Examination from the aspect of durability of the new method]
Subsequently, when the key top structure is mounted on an actual machine, it is necessary to consider its durability. In particular, as the thickness dimension of the thinnest sheet-like portion becomes thinner, there is a state in which anxiety remains about durability. Therefore, an experiment was conducted to confirm the number of keystrokes at which the thinnest sheet-like portion was torn by performing a keystroke test on each thickness dimension in Table 4 above. In addition, the buckling load of the disc spring-like member used in the keying test is also shown. In this experiment, the keystroke timing is 3.3 times / second, the load at the time of keystroke is 750 g, and a key sheet is arranged on the upper surface of the key top, and a keystroke test is performed via this key sheet. Is going. Further, a keystroke test was performed using a disc spring-like member having a buckling load of 170 g.

From the experimental results in Table 5, it was confirmed that depending on the use conditions, the thickness could be used in the range of 0.03 mm to 0.15 mm.

[9. Examination from the aspect of composition of new method]
Subsequently, based on Table 5 above, whether or not it can be used as an actual product by changing the component composition of the ultraviolet curable resin within the thickness range of 0.03 mm to 0.15 mm (to the product) As a result of examining whether or not it is applicable, the result is as shown in Table 6 below. Note that “whether or not it is applicable to a product in a keystroke test under a load of 750 g” in Table 6 is applicable to a product if no tearing occurs even after performing a keystroke test of 250,000 times. In the case where a break occurs in the keystroke test within 250,000 times, it is indicated as “X” because it is not applicable to the product. In addition, in Table 6, “whether or not the product can be applied to a keystroke test under a 10 kg load” is applicable to a product if no breakage occurs even after 5,000 keystroke tests. If a break occurs in the keystroke test within 5,000 times, it is indicated as “x” because it is not applicable to the product.

In Table 6 above, types 1 to 6 indicate the type (material) of the UV curable resin. These ultraviolet curable resins of types 1 to 6 are acrylate-based ultraviolet curable resins, and are adjusted to have respective measured hardnesses by changing the degree of polymerization or the crosslinking density.

From the experimental results in Table 6 above, it was confirmed that among the above-mentioned ultraviolet curable resins, those of type 3 to type 6 are suitable as actual products.

[10. Regarding actual manufacturing]
Based on the above experimental results and consideration results, the molding die 101 is manufactured and the key top structure as the product is manufactured. In this manufacture, the thickness dimension of the sheet-like portion is set to 0.03 mm in order to improve the click feeling (operation feeling) based on the results of Tables 4 and 5 described above. The thickness of the key top is set to 0.4 mm in view of the required key top height and FIG. When manufacturing such a key top structure, a film-like substrate having a thickness of 0.05 mm is used. In S04 of FIG. 3, the liquid ultraviolet curable resin is cured by being irradiated with ultraviolet rays for about 20 seconds. Moreover, in S06 of FIG. 3, using a separator machine, the film-like base material is pulled and peeled at an angle of 35 degrees with respect to the state before peeling.

After this, heat curing is performed for about 2 hours at 80 degrees Celsius to stabilize the dimensions of the molded product. Thereafter, for commercialization, decorative printing is performed on the back side of the key top member to form a colored layer, and further, the dried colored layer is heated and dried at 80 degrees Celsius for about 2 hours. Thereby, the key top structure as shown in FIG. 2 with decoration is obtained. In the key top structure obtained through these steps, warpage and local deformation do not occur, and in particular, at the end of the key top structure, there is no feeling of catching due to the occurrence of local deformation. Moreover, since it is manufactured without separating the key top, it has a key top structure with excellent assemblability.

<About Examples>
Next, an evaluation (example) regarding the operation when the key top structure 60 having the above-described configuration is pushed in will be described.

(Sample preparation method)
First, in order to manufacture the key top member 61, H17 (trade name) having a Shore D hardness of 50 degrees made by Nogawa Chemical as described above was prepared as an ultraviolet curable resin. The ultraviolet curable resin was cured by the manufacturing method shown in FIGS. 3 and 4 to produce the key top member 61. At this time, the key top 61a is manufactured using the base material 110 made of polyethylene terephthalate (PET) (thickness: 0.05 mm). The key top member 61 thus manufactured has a Shore D hardness of 50 degrees. Further, a colored layer 62 having a thickness of 10 μm was formed on the back side of the key top member 61 using a polyester-based ink as a material.

Further, a pressing element 70 having a protruding dimension of 0.2 mm was formed on the back surface side of the key top member 61. Further, the disc spring-like member 73 is provided in contact with the pressing element 70. The disc spring-like member 73 is in a state having a protruding dimension (height dimension) of 0.26 mm from the surface of the substrate 71. Further, the buckling load of the disc spring-like member 73 is 170 g.

Example 1
In such a state, while changing the thickness dimension S of the sheet-like portion 61b, the thickness dimension T of the key top 61a is not changed and is set to a fixed value of 0.4 mm, and the interval L between the key tops 61a is not changed. As a fixed value of 0.2 mm, the operational feeling and malfunction status of the key top structure 60 were evaluated according to the following criteria.
◎ ... Easy to push in and no malfunction.
○ ... There is a sense of incongruity when pushing in, but there is no malfunction.
Δ: There is a malfunction when pushing.

From the results of Table 7 above, it can be seen that if the thickness dimension S of the sheet-like portion 61b is in the range of 0.03 mm to 0.15 mm, it is easy to push in and there is no malfunction.

(Example 2)
Next, while changing the distance L between the key tops 61a, the thickness dimension T of the key top 61a is not changed, but is set to a fixed value of 0.4 mm, and the thickness dimension S of the sheet-like portion 61b is not changed. Assuming 0.05 mm, the operational feeling of the key top structure 60 and the situation of malfunction were evaluated according to the following criteria.
◎ ... Easy to push in and no malfunction.
○ ... There is a sense of incongruity when pushing in, but there is no malfunction.
Δ: There is a malfunction when pushing.

From the results of Table 8 above, it can be seen that if the distance L between the key tops 61a is within a range of 0.2 mm or more, it is easy to push in and there is no malfunction.

Table 9 summarizes the results of Example 1 and Example 2 described above.

From Table 9 above, the thickness dimension S of the sheet-like portion 61b is in the range of 0.03 mm to 0.15 mm, and the predetermined interval L between the plurality of key tops 61a is 0.2 mm to 1. It is preferable to be within the range of 0 mm. In that case, the key top structure 60 is easy to push in and does not malfunction.

(Example 3)
Next, an example in which the Shore D hardness of the key top member 61 is changed is shown below. In this embodiment, the thickness dimension T of the key top 61a is not changed and the fixed value is 0.4 mm, the thickness dimension S of the sheet-like portion 61b is not changed and the fixed value is 0.05 mm, and the key tops 61a are The interval L is not changed, and the fixed value is 0.2 mm. And the operational feeling of the key top structure 60 and the situation of malfunction were evaluated according to the following criteria.
◎ ... Easy to push in and no malfunction.
○ ... There is a sense of incongruity when pushing in, but there is no malfunction.
Δ: There is a malfunction when pushing.

From the results of Table 10 above, it can be seen that, in the key top member 61, if the Shore D hardness is in the range of 40 degrees to 80 degrees, it is easy to push in and there is no malfunction.

Here, in the state where the base material 110 is adhered to the key top member 61 (the state shown in FIG. 10), the deformation suppressing means in the claims is not configured. That is, the deformation suppressing means is realized for the first time by peeling the base material 110 from the key top member 61. That is, the key top member 61 contracts at the time of curing although the base material hardly contracts. Such deformation suppressing means for suppressing warpage and local deformation caused by shrinkage imbalance between the two members is embodied in the key top structure 60 by adding a step (labor) of peeling the base material 110. It can also be taken as.

Further, from the results of the above-described embodiments, when the Shore D hardness is 50 degrees (fixed value), the thickness dimension S of the sheet-like portion 61b is in the range of 0.03 mm to 0.15 mm, and It can be said that when the predetermined distance L between the plurality of key tops 61a is in the range of 0.2 mm to 1.0 mm, it functions well as the deformation suppressing means. In addition, when the Shore D hardness is in the range of 40 degrees to 80 degrees, it is possible to ensure a good function as a deformation suppressing means.

In addition, it can be said that the deformation permitting means in the claims functions well when the thickness dimension S of the sheet-like portion 61b is in the range of 0.03 mm to 0.15 mm. Among these, the thickness S of the sheet-like portion 61b is more preferably in the range of 0.03 mm to 0.10 mm, and even more preferably in the range of 0.03 mm to 0.05 mm. The deformation permitting means pushes only the disc spring-like member 73 (pressed object) of the pressed key top 61a when one of the key tops 61a is pressed from the top surface side, and the pressed key. It is preferable for the key top 61a other than the top 61a to be pushed independently so as not to push the disc spring-like member 73 (the pushing object).

<Effect>
According to the manufacturing method of the key top structure 60, the portable terminal 10 (electronic device), and the key top structure 60 having the above-described configuration, the ultraviolet curable resin contracts upon curing, but the key top member 61 is changed to the base material. Since the deformation suppressing means is realized by peeling 110, it is possible to suppress deformation due to shrinkage of the key top member 61 after curing. For this reason, it is possible to suppress deformation of the key top structure 60 so that the front surface side (the top surface side) is concave.

In the present embodiment, since the deformation suppression means is realized by peeling the base material 110 from the key top member 61 after the shrinkage after curing falls within a predetermined range, the key top structure 60 ( The key top member 61) is not bonded to a base material that is not excellent in stretchability. Therefore, when the user pushes the key top structure 60, it is possible to eliminate a state where the click feeling is not excellent.

In addition, in the present embodiment, local deformation at the end of the key top structure 60 can be suppressed, and the feeling of catching at the end can be eliminated. Here, in a state where a feeling of catching due to local deformation occurs, when an unexpected peeling force is applied to the end where the feeling of catching occurs, the key top member 61 may be peeled off from the base material 110. In the invention, since the base material 110 is peeled off to form the key top structure 60, such a problem can be eliminated.

In particular, the portable terminal 10 as shown in FIG. 1 employs a key layout called a “quarty keyboard layout”, so that the number of key tops 61 is larger than that of a normal cellular phone device or the like. It has become. Here, while the size of the portable terminal 10 is limited, the area of the key top 61 is increased while arranging a large number (for example, 30 or more) of the key tops 61, and the finger is pressed well. If it is going to ensure the property, the space | interval of the adjacent keytops 61 will necessarily become a small thing. By applying the key top structure 60 according to the present embodiment to such a portable terminal 10, it is possible to suppress the deformation that the surface side of the key top structure 60 becomes concave as described above, while being excellent in the click feeling. In addition, the above-mentioned catching feeling can be eliminated.

Further, in the present embodiment, the thickness S of the sheet-like portion 61b is in the range of 0.03 mm to 0.15 mm, and the predetermined interval L between the plurality of key tops 61a is 0.2 mm to It is preferable to be within the range of 1.0 mm.

If comprised in this way, while being able to suppress more favorably the deformation | transformation by the shrinkage | contraction after hardening of the keytop member 61, when a user pushes in the keytop structure 60, it shall be excellent in the click feeling. be able to.

In the present embodiment, it is preferable that the key top member 61 is provided with a Shore D hardness in the range of 40 degrees to 80 degrees. If comprised in this way, while being able to suppress more favorably the deformation | transformation by the shrinkage | contraction after hardening of the keytop member 61, when a user pushes in the keytop structure 60, it shall be excellent in the click feeling. be able to.

Furthermore, in the present embodiment, when any key top 61a is pushed in from the top surface side, the key top structure 60 pushes only the pushed object of the pushed key top 61a, and the pushed key. It is preferable to provide a deformation allowing means for allowing the key tops 61a other than the top 61a to be pushed independently so as not to push the object to be pushed.

In the case of such a configuration, it is possible to reliably push only the disc spring-like member 73 corresponding to the pushed key top 61a. For this reason, when the key top structure 60 is used in an electronic device such as the mobile terminal 10, it is possible to prevent a malfunction at the time of pressing.

In the present embodiment, the housing portion 20 is provided with an installation site for installing the key top structure 60, and the installation site directly contacts or indirectly touches the key top structure 60. It is preferable to become a part of the component of the deformation | transformation suppression means by contacting. If comprised in this way, it will become possible to suppress the deformation | transformation by the shrinkage | contraction after hardening of the keytop member 61 still more favorably. For this reason, it is possible to further favorably prevent the key top structure 60 from being deformed so as to be concave.

Further, in the present embodiment, as shown in FIG. 7B, when the ultraviolet curable resin M is in an uncured state, the portion closer to the center than the end of each side of the key top 61 is outside (key It protrudes to the side away from the inside of the top 61. In addition, as shown on the right side of FIG. 7B, a key top 61 having a specified size is formed by curing shrinkage. Thereby, the key top 61 with little influence of curing shrinkage can be realized.

<Modification>
As described above, the key top structure 60, the portable terminal 10 as an example of the electronic device, and the manufacturing method of the key top structure 60 according to the embodiment of the present invention have been described. However, the present invention can be variously modified in addition to this. It has become. This will be described below.

In the above embodiment, the key top structure 60 may be manufactured as shown in FIG. That is, the base 110 is curved and brought into contact with the molding die 101 so that the top surface side of the key top member 61 is convex (for this purpose, the molding surface 101a of the molding die 101 is curved so as to be concave. In this state, the liquid ultraviolet curable resin M may be cured. In this case, due to the shrinkage when the liquid ultraviolet curable resin M is cured, the sheet-like portion 61b and the base material 110 are both kept substantially horizontal, horizontal, or horizontal during the curing. Can do.

Note that the degree of curvature of the base material 110 (the degree of curvature of the molding surface 101a) is substantially the same between the sheet-like portion 61b and the base material 110 at the time of curing due to shrinkage when the liquid ultraviolet curable resin M is cured. It is preferable to set it to a level that can be regarded as horizontal or horizontal or horizontal.

Further, in the above-described embodiment, the case where the mobile terminal 10 as shown in FIG. 1 is used has been described. However, the mobile terminal is not limited to that shown in FIG. For example, the present invention may be applied to a mobile phone device 10A as a kind of mobile terminal as shown in FIG. 12 includes a housing unit 20, a display unit 30, a cursor key unit 40, and a key arrangement unit 50, similarly to the mobile terminal 10 shown in FIG. .

The cursor key portion 40 includes an annular button portion 41 and a center button portion 42. The cursor key portion 40 and the annular button portion 41 are opened from the opening of the housing portion 20 to a key top 61a (FIG. 2). The top side of (see) is protruding. Here, the annular button portion 41 has a portion to be pressed at intervals of 90 degrees, for example. Further, the center button portion 42 is a portion where a portion to be pressed (the top surface side of the key top 61 a) is surrounded by the annular button portion 41.

Further, in the key arrangement portion 50, the top surface side of the key top 61a protrudes from the opening of the housing portion 20 in the same manner as the cursor key portion 40. As shown in FIG. 1, the key arrangement unit 50 includes three key tops 61 a having the same shape, for example, three in the X direction and five in the Y direction.

Also in such a cellular phone device 10A, it is possible to suppress deformation due to shrinkage of the key top member 61 after curing. In addition, when the user presses the key top structure 60, it is possible to eliminate a state where the click feeling is not excellent. In addition, local deformation at the end of the key top structure 60 can be suppressed, the feeling of catching at the end can be eliminated, and an unexpected peeling force is applied to the end where the feeling of catching occurs, and the key top member It is possible to eliminate such a problem that 61 is peeled off from the substrate 110.

Further, in the above-described embodiment, the case where the top surface of the key top 61a is flat has been described. However, the shape of the top surface of the key top 61a is not limited to a flat shape, and may be other shapes (for example, a curved surface shape, a concave shape, a convex shape, a corrugated shape, etc.).

10 ... Mobile terminal (corresponds to an example of electronic equipment)
DESCRIPTION OF SYMBOLS 20 ... Housing | casing part 30 ... Display part 40 ... Cursor key part 50 ... Key arrangement part 60 ... Keytop structure 61 ... Keytop member 61a ... Keytop 61b ... Sheet-like part 62 ... Colored layer 70 ... Presser 71 ...

Substrate

72a , 72b ... fixed contact 73 ... disc spring-like member (corresponding to an example of an object to be pushed in)
DESCRIPTION OF SYMBOLS 100 ... Manufacturing apparatus 101 ... Mold 101a ... Molding surface 102 ... Feed roller 103 ... Recessed part 105 ... Ultraviolet irradiation apparatus M ... Ultraviolet curable resin

Claims

Inject liquid UV curable resin into the recess of the mold,
Cover the ultraviolet curable resin injected into the recess, and position the substrate in close contact with the ultraviolet curable resin,
Irradiation of ultraviolet rays to the liquid ultraviolet curable resin to cure the ultraviolet curable resin,
Remove the base material and the key top member from the molding die,
After that, the base material is peeled off from the integrated body of the base material and the key top member, thereby arranging the sheet-like portions and the key tops arranged in rows at predetermined intervals and having a thickness dimension larger than that of the sheet-like portion. Composing the components,
A key top structure comprising the key top member.
The key top structure according to claim 1,
About at least one side of the portion corresponding to the key top in the liquid ultraviolet curable resin, a portion closer to the center than the end of the side protrudes to the side away from the inside of the key top,
In the key top member after curing, the one side constituting the key top has a linear shape with the protrusion to the side away from the inside of the key top being eliminated by curing shrinkage,
Key top structure characterized by that.
By curing the ultraviolet curable resin, a sheet-like portion and a plurality of key tops are formed, and the key top is provided with a thickness dimension larger than that of the sheet-like portion, and the plurality of key tops are predetermined. A key top member having portions arranged in a row in a state having an interval;
Deformation suppression means for suppressing deformation due to shrinkage after curing of the keytop member when forming the keytop member by curing the ultraviolet curable resin with respect to the substrate;
A key top structure characterized by comprising:
The key top structure according to claim 3,
The deformation suppressing means is configured by peeling the base material from the key top member after the shrinkage after curing of the key top member is within a predetermined range.
Key top structure characterized by that.
The key top structure according to any one of claims 1 to 4,
The thickness dimension of the sheet-like portion is in the range of 0.03 mm to 0.15 mm, and the predetermined interval between the plurality of key tops is in the range of 0.2 mm to 1.0 mm. Key top structure that is characteristic.
By curing the ultraviolet curable resin, a sheet-like portion and a plurality of key tops are formed, and the key top is provided with a thickness dimension larger than that of the sheet-like portion, and the plurality of key tops are predetermined. Comprising a key top member having portions arranged in a row in a state having an interval;
The thickness dimension of the sheet-like portion is in the range of 0.03 mm to 0.15 mm, and the predetermined interval between the plurality of key tops is in the range of 0.2 mm to 1.0 mm.
Key top structure characterized by that.
The key top structure according to claim 5,
The key top structure is characterized in that the Shore D hardness is provided in a range of 40 degrees to 80 degrees.
The key top structure according to claim 6,
The key top structure is characterized in that the Shore D hardness is provided in a range of 40 degrees to 80 degrees.
The key top structure according to claim 1,
The key top member, when any one of the key tops is pushed in from the top surface side, pushes only the pushing object of the pushed key top, and the other key other than the pushed key top. A deformation allowing means for allowing the top to be pushed independently so as not to push the pushing object;
Key top structure characterized by that.
The key top structure according to claim 3,
The key top member, when any one of the key tops is pushed in from the top surface side, pushes only the pushing object of the pushed key top, and the other key other than the pushed key top. A deformation allowing means for allowing the top to be pushed independently so as not to push the pushing object;
Key top structure characterized by that.
The key top structure according to claim 6,
The key top member, when any one of the key tops is pushed in from the top surface side, pushes only the pushing object of the pushed key top, and the other key other than the pushed key top. A deformation allowing means for allowing the top to be pushed independently so as not to push the pushing object;
Key top structure characterized by that.
A key top structure according to claim 3 or 4 is provided,
An installation site for installing the key top member;
This installation site becomes a part of the component of the deformation suppressing means by directly contacting or indirectly contacting the key top member.
An electronic device characterized by that.
An injection step of injecting a liquid UV curable resin into the recess of the molding die;
An installation step of covering the ultraviolet curable resin injected into the recess and positioning the base material in close contact with the ultraviolet curable resin;
A curing step of irradiating the liquid ultraviolet curable resin with ultraviolet rays to cure the ultraviolet curable resin by a predetermined amount to produce a key top member;
A removal step of removing the integrated body of the base material and the key top member from the molding die,
A peeling step of peeling the base material from an integral body of the base material and the key top member;
A method for manufacturing a key top structure, comprising: