JP2011165630A - Member for entry sheets, and method of producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent appearance deterioration of the operation surface of a member for entry sheets. <P>SOLUTION: The member 2 for entry sheets includes a key or a key assembly plate 2, having one or more through-holes 5 in the direction from top to bottom; a first resin layer 8 which is formed inside the through-holes 5; and a second resin layer 9, which is layered on the first resin layer 8 in the depth direction and thinner than the first resin layer 8, at least in an area of the through-holes 5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an input sheet member and a manufacturing method thereof.

  Conventionally, diversification of the design of members for input sheets used for operation units of electronic devices such as mobile phones and personal digital assistants (PDAs) has been demanded. As one form of a key sheet excellent in design, there is a non-translucent key sheet in which a through hole for displaying characters or the like is formed by press molding, laser etching, chemical etching, or the like. Some of the through holes are blocked with a light-transmitting resin (see, for example, Patent Document 1). When such a key sheet is illuminated from the back side, characters or symbols appear to shine.

JP 2007-115633 A

  However, the key sheet described in Patent Document 1 has the following problems. That is, it is a problem that it is difficult to accurately fill the translucent resin filled in the through hole so as not to contain bubbles and to be excessive or insufficient. Further, when the resin is filled after the resin is filled and then cured, there is a problem that a gap is easily formed between the resin and the inner wall of the through hole due to shrinkage at the time of curing. In particular, as electronic devices become thinner, as the key sheet becomes thinner, it becomes more difficult to accurately fill the through holes with resin.

  Therefore, fill the through hole with excess resin, cure the resin in a state overflowing from the through hole, and then mechanically remove the resin part protruding from the key sheet by grinder, buff, blast or barrel polishing etc. Is preferred. When the resin portion protruding from the key sheet is mechanically removed, defects such as cracks or pinholes are likely to occur in the resin or at the interface between the resin and the through hole due to the mechanical removal process.

  When defects such as cracks or pinholes exist in the resin inside the through hole, there may be a problem that the appearance of the key sheet is deteriorated. Furthermore, the adhesive or the like or a constituent component of the base sheet interposed between the back surface of the key sheet and the base sheet may move from the above defects to the operation surface side of the key sheet, thereby deteriorating the appearance of the key sheet. is there.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide an input sheet member and a method for manufacturing the same, which can prevent the appearance of the operation surface from being deteriorated.

  In order to achieve the above object, an embodiment of an input sheet member of the present invention is formed in a key or a key assembly plate having one or two or more through holes penetrating in the front and back direction, and in the through holes. The first resin layer and the second resin layer that is disposed at least in the depth direction of the through hole of the first resin layer and is thinner than the first resin layer in the region of the through hole And.

  Furthermore, the second resin layer can be preferably formed also on the inner surface of the through hole.

  Furthermore, the second resin layer can be preferably formed so as to cover the first resin layer and its periphery on the surface opposite to the operation surface of the key or the key assembly plate.

  Furthermore, the second resin layer can be preferably formed on the surface opposite to the operation surface of the key or key assembly plate as a layer thicker than the height at which the first resin layer protrudes from the through hole.

  Furthermore, the second resin layer can be preferably a printing layer.

  Furthermore, the through-hole may preferably be provided with a taper or a counterbore that changes the hole diameter in the depth direction.

  An embodiment of the method for manufacturing an input sheet member of the present invention is a method for manufacturing an input sheet member comprising a key or a key assembly plate having one or more through holes penetrating in the front and back direction. The first resin layer forming step of forming the first resin layer in the through hole, and before or after the first resin layer formation, the through hole of the first resin layer is at least in the region of the through hole. A second resin layer forming step that is arranged in the depth direction and forms a second resin layer thinner than the first resin layer.

  ADVANTAGE OF THE INVENTION According to this invention, the external appearance fall by the side of the operation surface in the input sheet member can be prevented.

It is a front view of a mobile telephone provided with the member for input sheets which concerns on the 1st Embodiment of this invention. It is a front view of the member for input sheets integrated in the mobile telephone shown in FIG. FIG. 3 is a cross-sectional view taken along line AA of FIG. 2 for the input sheet member shown in FIG. 2. It is a flowchart which shows the schematic flow of manufacture of the member for input sheets which concerns on the 1st Embodiment of this invention. FIG. 5 is a diagram showing a state of each step of the input sheet member in FIG. 4, and is a cross-sectional view similar to the region indicated by B in FIG. 3. It is an AA line sectional view similar to the field shown by B of Drawing 3 about the member for input sheets concerning a 2nd embodiment of the present invention. It is a flowchart which shows the schematic flow of manufacture of the member for input sheets which concerns on the 2nd Embodiment of this invention. It is a figure which shows the state in each step of the member for input sheets of FIG. 6, Comprising: It is an AA sectional view similar to the area | region shown by B of FIG. It is the AA sectional view similar to the area | region shown by B of FIG. 3 about the member for input sheets which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows the schematic flow of manufacture of the member for input sheets which concerns on the 3rd Embodiment of this invention. It is a figure which shows the state in each step of the member for input sheets of FIG. 9, Comprising: It is sectional drawing similar to the area | region shown by B of FIG. It is sectional drawing at the time of seeing only the area | region similar to the area | region shown by B of FIG. 3 about the member for input sheets which concerns on the modification of this invention. It is sectional drawing at the time of seeing only the area | region similar to the area | region shown by B of FIG. 3 about the member for input sheets which concerns on the modification of this invention. It is sectional drawing at the time of seeing only the area | region similar to the area | region shown by B of FIG. 3 about the member for input sheets which concerns on the modification of this invention. It is sectional drawing at the time of seeing only the area | region similar to the area | region shown by B of FIG. 3 about the member for input sheets which concerns on the modification of this invention. It is sectional drawing at the time of seeing only the area | region similar to the area | region shown by B of FIG. 3 about the member for input sheets which concerns on the modification of this invention. It is sectional drawing at the time of seeing only the area | region similar to the area | region shown by B of FIG. 3 about the member for input sheets which concerns on the modification of this invention. It is sectional drawing at the time of seeing only the area | region similar to the area | region shown by B of FIG. 3 about the member for input sheets which concerns on the modification of this invention. It is sectional drawing which shows the through-hole vicinity of the key sheet | seat in the modification of the member for input sheets of this invention. It is sectional drawing which shows the through-hole vicinity of the key sheet | seat in the modification of the member for input sheets of this invention. It is sectional drawing which shows the through-hole vicinity of the key sheet | seat in the modification of the member for input sheets of this invention. It is sectional drawing which shows the through-hole vicinity of the key sheet | seat in the modification of the member for input sheets of this invention.

  Next, embodiments of the input sheet member and the manufacturing method thereof according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a front view of a mobile phone 1 including an input sheet member 2 according to the first embodiment of the present invention. FIG. 2 is a front view of the input sheet member 2 incorporated in the mobile phone 1 shown in FIG.

  As shown in FIG. 1, a mobile phone 1 that is an example of an electronic device includes an input sheet member 2 according to the present embodiment on its operation surface. In this specification, the “input sheet member” means a push button switch member that is turned ON / OFF by a pressing operation, and an input sheet member that is used for an input device that can input an instruction simply by touching without pressing. Etc. Moreover, you may use for the decoration display parts other than the area | region which a user operates. As shown in FIG. 2, on the operation surface side of the input sheet member 2, a key sheet 3 that is an example of a key assembly plate and a central key 4 that is separately disposed inside the key sheet 3 are exposed. Yes. A plurality of keys are arranged on the key sheet 3 so as to be connected to the key sheet 3. Here, in FIG. 2, the key displaying “1” is “key 3a”, the key displaying “2” is “key 3b”, and the key displaying “3” is “key 3c”. When other keys are included, they are referred to as “keys 3a, 3b, 3c, etc.”. Hereinafter, the operation surface side is referred to as the front surface side, and the surface side opposite to the operation surface is referred to as the back surface side. Moreover, the distance between the front surface and the back surface of the key sheet 3 is referred to as thickness.

  3 is a cross-sectional view of the input sheet member 2 shown in FIG. In FIG. 2 and subsequent cross-sectional views, the thickness ratio of each member is changed from the actual ratio in consideration of easy viewing.

  The keys 3a, 3b, 3c, etc. in the key sheet 3 exposed on the surface side of the input sheet member 2 are portions pressed by the user. As the key sheet 3, any material having a predetermined strength can be used without any particular limitation. For example, stainless steel having a thickness of about 0.1 to 0.5 mm, aluminum, titanium, magnesium, or a material thereof. A metal plate such as an alloy can be used. Among these, stainless steel is preferable because it is thin and has high strength and can be obtained at low cost. Moreover, when the member 2 for input sheets is used as a key sheet | seat of the member for press switches, it is preferable that it is a metal plate about 0.1-0.3 mm. However, the key sheet 3 may be mainly formed from a member other than metal, for example, resin, ceramics, glass, or a composite thereof. Moreover, you may employ | adopt the member 2 for input sheets which has the form which has arrange | positioned the separate key with the key sheet 3 separately. The key sheet 3 preferably has a smooth back surface for the purpose of improving the fixing force with the base sheet 7.

  The input sheet member 2 includes a base sheet 7 via an adhesive layer 6 on the back side of the key sheet 3. The key sheets 3a, 3b, 3c and the like have through holes 5 in which shapes such as letters, numbers, symbols or drawings are cut out. The through hole 5 is a hole that penetrates the front surface and the back surface of the key sheet 3. Further, inside the through-hole 5, a first resin layer 8 is formed on the front surface side, and a second resin layer 9 is formed on the back surface side. In the present embodiment, the first resin layer 8 has a convex shape that overflows from the through hole 5 and slightly protrudes from the back surface of the key sheet 3 and protrudes toward the back surface direction. The 2nd resin layer 9 is provided only in the back surface part of the through-hole 5 so that the convex-shaped part may be covered. Preferably, the second resin layer 9 is formed thinner in the depth direction of the through hole 5 than the first resin layer 8. For example, when the thickness of the key sheet 3 is 200 μm, the first resin layer 8 is formed in the through hole 5 with a thickness of about 210 μm, but the second resin layer 9 is about 10 μm thick. Now, it is formed inside the through hole 5. The second resin layer 9 preferably has a lower shrinkage before and after curing than the first resin layer 8. Therefore, compared to the first resin layer 9, the second resin layer 9 is less likely to peel off from the key sheet 3, and pinholes or cracks are less likely to occur.

  As the material of the first resin layer 8, a resin having a hardness higher than that of the second resin layer 9 can be suitably used. Further, as the material of the first resin layer 8, it is preferable to use a material having a low viscosity that can be easily filled to every corner of the through hole 5 when filling the through hole 5 in an uncured state. For example, acrylic, urethane, polyester, polycarbonate, methacrylate, or silicone UV curable resin, visible light curable resin, electron beam curable resin, or thermosetting resin is used as the material for the first resin layer 8. Can be suitably used. Among them, a UV curable resin that is low in cost, has a high curing rate, and is advantageous for productivity is preferable. The first resin layer 8 may be formed in the through hole 5 by any method. For example, the first resin layer 8 is filled once by filling the through hole 5 with the material of the first resin layer 8 using a dispenser or the like. The first resin layer 8 having a sufficient thickness can be formed in the through hole 5 by the operation. The material of the first resin layer 8 is preferably lower in viscosity than the material of the second resin layer 9 in an uncured state. This is because when the first resin layer 8 is filled into the through-hole 5, bubbles or the like are less involved. For example, the material of the first resin layer 8 preferably has a viscosity of about 10 to 1000 cps in an uncured state, and more preferably has a viscosity of about 10 to 500 cps.

  As the material of the second resin layer 9, a resin that can form a film with a uniform film thickness when cured than the first resin layer 8 can be suitably used. Further, as the material of the second resin layer 9, it contributes to the improvement of the fixing force by being interposed between the key sheet 3 and the first resin layer 8 and between the key sheet 3 and the adhesive layer 6. It is more preferable to use a material having a proper binder function. For example, acrylic, urethane, ester, epoxy, vinyl chloride, acrylic, or silicone ink can be suitably used as the material of the second resin layer 9. Further, as the material of the second resin layer 9, it is more preferable to use a material (low shrinkage material) having a lower shrinkage rate before and after curing than the first resin layer 8. The second resin layer 9 is preferably a printing layer formed by screen printing, pad printing or other printing techniques. In order to form the second resin layer 9 that is smooth and does not entrain air bubbles by printing, the viscosity of the second resin layer 9 when forming the second resin layer 9 is about 100 to 10,000 cps. Is preferable, and about 1000 to 10000 cps is more preferable. Further, when a translucent resin is used as the first resin layer 8 and the second resin layer 9, the light is transmitted from the region of the filler inside the through hole 5 when illuminated from the back side of the key sheet 3. Therefore, the user can easily visually recognize the shape of characters and the like even in a dark place.

  The adhesive layer 6 may be made of any material as long as the key sheet 3 and the base sheet 7 can be bonded. For example, the adhesive layer 6 can be a layer made of a double-sided tape, a hot melt tape, a cyanoacrylate resin, a urethane resin, a silicone resin, or a resin having a low softening point when heated. When a cyanoacrylate adhesive is used as the material of the adhesive layer 6, it can be cured by the action of moisture in the air. The adhesive layer 6 may be provided only in the through hole 5 portion, or may be provided on the back surface side of the key sheet 3 excluding the through hole 5. Further, the adhesive layer 6 may be provided on the entire back surface of the key sheet 3, or the adhesive layer 6 may be provided only on a part of the key sheet 3 (for example, the dot-like adhesive layer 6). .

  The base sheet 7 is a member that supports the key sheet 3. In addition, the base sheet 7 is flexible and elastic so that a switch member (not shown) or the like provided therebelow can be pushed in when the key 3a, 3b, 3c or the like is pressed from the front side. It is preferably composed of a material. Examples of the material for the base sheet 7 include thermosetting elastomers such as silicone rubber, urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber or styrene butadiene rubber, urethane type, ester type, Styrene-based, olefin-based, butadiene-based, fluorine-based thermoplastic elastomers, or composites thereof can be used. Among these materials, it is preferable to use urethane-based elastomer, silicone rubber, or a composite product having high durability. Moreover, it is preferable that the surface of the base sheet 7 is smooth for the purpose of improving the fixing force with the key sheet 3.

  By configuring the input sheet member 2 as described above, it is possible to prevent the appearance of the operation surface side of the key sheet 3 from being deteriorated. This is because the second resin layer 9 seals the through-hole 5 even if cracks or pinholes are present inside the first resin layer 8.

  Moreover, the adhesive force of the key sheet 3 and the base sheet 7 can be improved by comprising the input sheet member 2 as described above. This is because the adhesiveness between the key sheet 3 and the base sheet 7 is improved by forming the second resin layer 9 having high smoothness on the back surface side of the first resin layer 8.

  Next, the manufacturing method of the member 2 for input sheets is demonstrated. FIG. 4 is a flowchart showing a schematic flow of manufacturing the input sheet member 2. FIG. 5 is a view showing the state of the input sheet member 2 in each step, and is a cross-sectional view similar to the region indicated by B in FIG. 3.

  First, as shown in FIG. 5A, the through hole 5 is provided in the key sheet 3 (step S101). The through hole 5 can be provided in the key sheet 3 by laser processing, etching, punching, or the like. When the through hole 5 is provided, it can be formed from the front side, the back side, or both sides of the key sheet 3.

  Next, as shown in FIG. 5B, the film 10 is attached to the surface of the key sheet 3 (downward in FIG. 5) (step S102). The film 10 serves to protect the surface of the key sheet 3 and to fix the keys 3a, 3b, 3c and the like so as not to be displaced from predetermined positions. Further, when the uncured first resin layer 8 is injected (described later), the film 10 closes the through-hole 5 so that the uncured first resin layer 8 does not leak on the surface of the key sheet 3. Therefore, the film 10 may be any film as long as it can be attached to the surface of the key sheet 3, and a resin sheet with an adhesive can be suitably used.

  Next, as shown in FIG. 5C, the first resin layer 8 is formed inside the through-hole 5 from the back side of the key sheet 3 (above the paper surface in FIG. 5) (step S103). Specifically, it is preferable that the first resin layer 8 is filled with the material of the first resin layer 8 by a dispenser and then cured. The material of the first resin layer 8 may be filled into the through hole 5 by a method other than the dispenser. However, the material of the first resin layer 8 has a sufficient thickness and reaches every corner of the through hole 5. In order to fill, it is preferable to employ a dispenser. Moreover, you may perform the process of cutting a protrusion part with a grinder etc. after step S103.

  Next, as shown in FIG. 5D, the second resin layer 9 is formed in the through-hole 7 from the back side of the key sheet 3 (upper side of the paper in FIG. 5) (step S104). Specifically, it is preferable to form the second resin layer 9 in the portion of the through hole 7 by printing. Next, the adhesive layer 6 is formed on the back surface side of the key sheet 3, and the base sheet 7 is fixed to the key sheet 3 by heating and pressurizing. Finally, the film 10 is peeled off from the key sheet 3 to complete the input sheet member 2. In addition, you may adhere | attach the member 2 for input sheets and the base sheet 7 by melt | fusion etc., without passing through the contact bonding layer 6. FIG.

  By manufacturing the input sheet member 2 by the method described above, it is possible to prevent the appearance of the operation surface side of the key sheet 3 from being deteriorated. Even if there is a gap between the first resin layer 8 and the inner surface of the through-hole 5, or there are cracks or pinholes inside the first resin layer 8, the first resin layer 8 This is because the second resin layer 9 seals the through hole 5 after being cured. Moreover, since the 2nd resin layer 9 is a thin layer formed by printing, it is hard to influence the external appearance of the member 2 for input sheets.

(Second Embodiment)
Next, the input sheet member 20 according to the second embodiment will be described with reference to the drawings. FIG. 6 is a cross-sectional view of the input sheet member 20 when a region similar to the region indicated by B in FIG. 3 is viewed in the same cross section. In addition, illustration of the contact bonding layer 6 and the base sheet 7 is abbreviate | omitted in each sectional drawing after FIG. Further, the same components as those of the input sheet member 2 according to the first embodiment will be described using the same numbers.

  Similar to the input sheet member 2, the input sheet member 20 has a through hole 5 in the key sheet 3. In the input sheet member 20, the first resin layer 25 and the second resin layer 26 are formed inside the through hole 5. The second resin layer 26 is formed to cover the periphery of the opening of the through hole 5 on the back surface side of the key sheet 2. Specifically, the second resin layer 26 is formed as a concave-shaped layer that is connected to the inner surface of the through hole 5 and the front side of the key sheet 3 from the back surface side of the key sheet 3 in the through hole 5. That is, the second resin layer 26 covers the inner surface of the through hole 5, the front surface side opening of the through hole 5, and the back surface of the key sheet 2. Further, the first resin layer 25 is formed in a recess formed at a position corresponding to the through hole 5 by the second resin layer 26.

  By configuring the input sheet member 20 as described above, it is possible to prevent the appearance of the operation surface side of the key sheet 3 from being deteriorated. Since the second resin layer 26 covers the back surface of the key sheet 3 widely, even if there is a gap between the inner surface of the through hole 5 and the resin filled in the through hole 5, the back surface of the key sheet 3 This is because the adhesive or the like provided on the side is less likely to advance to the front side than the second resin layer 26.

  In addition, by configuring the input sheet member 20 as described above, the adhesive force between the key sheet 3 and the first resin layer 25 can be further improved. In addition, since the second resin layer 26 functions as a binder between the first resin layer 25 and the adhesive layer 6, the adhesive force between the first resin layer 25 and the adhesive layer 6 can be improved. .

  Next, a method for manufacturing the input sheet member 20 will be described. FIG. 7 is a flowchart showing a schematic flow of manufacturing the input sheet member 20. FIG. 8 is a cross-sectional view when the state of the input sheet member 20 in each step is viewed in the same cross section as the region indicated by B in FIG. 3. Steps S201 to S202 are the same as steps S101 to S102 of the input sheet member 2 according to the first embodiment, and thus the description thereof is omitted.

  First, as shown in FIG. 8A, the second resin layer 26 is formed on the entire back surface of the key sheet 3 from the back surface side of the key sheet 3 (above the paper surface of FIG. 8) (step S203). Specifically, the second resin layer 26 is formed on the entire back surface of the key sheet 3 by printing from the back surface side with the front surface side of the key sheet 3 facing down.

  Next, as shown in FIG. 8B, from the back surface side of the key sheet 3 (above the paper surface of FIG. 8) to the concave portion formed by the second resin layer 26 inside the through hole 5. Then, the material of the first resin layer 25 is filled with a dispenser or the like (step S204). Next, the adhesive layer 6 is formed on the back surface side of the key sheet 3 and the key sheet 3 and the base sheet 7 are fixed by heating and pressurizing the base sheet 7. Finally, the input sheet member 20 is completed by peeling the film 10.

(Third embodiment)
Next, an input sheet member 30 according to a third embodiment will be described with reference to the drawings. 9 is a cross-sectional view of the input sheet member 30 when a region similar to the region indicated by B in FIG. 3 is viewed in the same cross section as FIG. The same components as those of the input sheet member 2 according to the first embodiment will be described using the same numbers.

  Similar to the input sheet member 2 according to the first embodiment, the input sheet member 30 has a through hole 5 in the key sheet 3. Further, in the input sheet member 30, the first resin layer 35 is formed in the entire inner region of the through hole 5, and the key sheet 2 is formed so that the second resin layer 36 covers the first resin layer 35. It is formed on the back side.

  The first resin layer 35 filled in the through-hole 5 is formed in a convex shape protruding in the back surface direction due to surface tension when not cured or shrinkage when cured. The second resin layer 36 is formed thicker than the height at which the first resin layer 35 protrudes from the through hole 5. The second resin layer 36 covers the back surface of the key sheet 3 so that a step due to the convex portion of the first resin layer 35 does not occur.

  By configuring the input sheet member 30 as described above, the adhesive force between the key sheet 3 and the base sheet 7 can be further improved. This is because the back surface of the key sheet 3 including the through hole 5 is smoothed by covering the back surface of the key sheet 3 with the second resin layer 36. Further, since the base sheet 7 can be bonded in a wider area on the back surface of the key sheet 3, the adhesive force between the base sheet 7 and the key sheet 3 is improved.

  Next, a method for manufacturing the input sheet member 30 will be described. FIG. 10 is a flowchart showing a schematic flow of manufacturing the input sheet member 30. FIG. 11 is a cross-sectional view similar to the region indicated by B in FIG. 3 with respect to the input sheet member 30 in each step. Note that steps S301 to S302 are the same as steps S101 to S102 of the input sheet member 2 according to the first embodiment, and a description thereof will be omitted.

  First, as shown in FIG. 11A, the material of the first resin layer 35 is placed inside the through-hole 5 with a dispenser or the like with the back side of the key sheet 3 (upper side in FIG. 11) facing up. Fill and cure to form the first resin layer 35 (step S303). The material of the first resin layer 35 may be filled slightly in excess with respect to the capacity of the through-hole 5, or may be filled slightly in short.

  Next, as shown in FIG. 11B, the second resin layer 26 is formed by printing or the like so as to cover the first resin layer 35 from the back side of the key sheet 3 (above the paper surface in FIG. 11). Form (step S304). At this time, it is preferable to form the second resin layer 36 with a thickness larger than the protruding height of the unevenness of the first resin layer 35 so that the back surface of the key sheet 3 is smooth. Next, the adhesive layer 6 is formed on the back surface side of the key sheet 3, and the base sheet 7 is fixed to the key sheet 3 by heating and pressurizing. Finally, the film 10 is peeled off to complete the input sheet member 30.

  The input sheet members 2, 20, and 30 and the manufacturing methods thereof according to the present invention have been described above, but the present invention is not limited to the above-described embodiments, and can be implemented with various modifications.

  For example, in the above-described embodiment, in FIG. 3, the adhesive layer 6 is widely provided on the back surface of the key sheet 3, but this is not a limitation. Of the key sheet 3, the adhesive layer 6 may be provided only in a portion other than the through hole 5, or the adhesive layer 6 may be provided only in the through hole 5 portion. However, when the adhesive layer 6 is widely provided on the back surface of the key sheet 3 including the portion of the through hole 5, the unevenness of the resin formed inside the through hole 5 can be reduced, so that the key sheet 3 and the base sheet 7 The adhesion can be further improved.

  Moreover, in each above-mentioned embodiment, after forming the 1st resin layer 8,25,35, the process of shaving the part which protruded from the key sheet | seat 3 with the grinder etc. is not essential. In the case where there is no step of cutting a portion protruding from the key sheet 3 with a grinder or the like, the input sheet member 2 can be manufactured more efficiently. Furthermore, since vibration by the grinder is not applied, cracks or pinholes are hardly generated in the first resin layers 8, 25, and 35.

  Further, the base sheet 7 is not essential. This is because, in particular, in the case of the key sheet 3 in which a plurality of key sheets 3a, 3b, 3c, etc. are connected, it functions even without the base sheet 7.

  12 to 18 are cross sections when the input sheet members 2a, 2b, 2c, 2d, 20a, 20b, and 20c according to the modification of the present embodiment are viewed only in the region indicated by B in FIG. FIG. In each figure, the front side is shown on the upper side of the drawing and the back side is shown on the lower side of the drawing.

  In the embodiment, the second resin layer 9 is provided on the back surface side of the first resin layer 8, but it is not limited to such a form. As shown in FIGS. 12 and 13, the second resin layer 9 may be provided on the surface side of the first resin layer 8. When the second resin layer 9 is provided on the surface side of the first resin layer 8, the second resin layer 9 is also in close contact with the inner surface of the through hole 5 to seal the through hole 5. The effect of stopping becomes higher.

  In each of the above-described embodiments, at least one of the first resin layers 8, 25, 35 and the second resin layers 9, 26, 36 is formed so as to fill the inside of the through hole 5. However, it is not limited to such a form. As shown in FIGS. 12 and 14, a part of the back surface side of the through hole 5 is not filled with any of the first resin layers 8, 25, 35 or the second resin layers 9, 26, 36. It is good also as a form.

  In the first embodiment, the first resin layer 8 and the second resin layer 9 are formed so as to overflow from the through hole 5, but the present invention is not limited to such a form. As shown in FIG. 15, the first resin layer 8 may be filled so as not to fill the through-hole 5, and may be formed substantially flush with the back surface of the key sheet 3.

  Further, in the second embodiment, the material of the first resin layer 25 is excessively filled in the recess formed by the second resin layer 26, and the first resin layer 25 is the back surface of the key sheet 3. Although it forms as a convex part which protrudes to the side, it is not restricted to such a form. As shown in FIGS. 16 and 17, the first resin layer 25 may be formed with a shortage with respect to the through hole 5.

  In the second embodiment, the first resin layer 25 is formed in the recess formed by the second resin layer 26, but the present invention is not limited to such a form. For example, as shown in FIG. 17, the material of the first resin layer 25 is filled on the surface side of the through hole 5 in a shortage with respect to the through hole 5, and then penetrates the back surface side of the first resin layer 25. The second resin layer 26 may be formed on the entire back surface of the key sheet 3 along the inner surface of the hole 5. Also, as shown in FIG. 18, the material of the first resin layer 25 is filled in the surface side of the through hole 5 in a shortage with respect to the through hole 5, and then the remaining space of the through hole 5 is filled. The second resin layer 26 may be widely formed on the back surface of the key sheet 3. In the form shown in FIGS. 17 and 18, since the second resin layer 26 is in close contact with the wall surface of the through hole 5, in addition to the effect of sealing the through hole 5 being increased, the base sheet 7 is Since it adheres to the smooth second resin layer 26, the adhesive force between the key sheet 3 and the base sheet 7 can be further improved.

  Further, in each of the above-described embodiments, the through hole 5 is the through hole 5 having the same opening area on the front surface side and the back surface side and the same width from the front surface side to the back surface side. However, it is not limited to such a form. The through hole 5 may not have the same width from the front surface side to the back surface side. Moreover, the through-hole 5 does not need to have the same opening area on the front surface side and the back surface side.

  19 to 22 are cross-sectional views showing the vicinity of the through holes 5a to 5d of the key sheet 3 in a modification of the input sheet members 2, 20, and 30 of the present invention. For example, as shown in FIG. 19, the opening area of the front surface side and the back surface side of the through hole 5a may be larger than the opening area of the central portion in the thickness direction of the through hole 5a. That is, the so-called cross section having a taper 40, 41 so as to reduce the opening area from the front surface side and the back surface side of the through hole 5a toward the inside of the through hole 5a may have a wedge shape. When the cross-section of the through hole 5a is wedge-shaped, when light is illuminated from the back surface side, the light is condensed at the taper portions 40 and 41 from the back surface side of the through hole 5a, so that the through hole 5a is displayed. Letters appear to shine with higher brightness. Furthermore, there is an effect that the resin formed in the through hole 5a is difficult to be removed from the through hole 5a. The tapers 40 and 41 may be provided from both the front side and the back side of the key sheet 3 or may be provided from only one side.

  In addition, as shown in FIG. 20, the portion having the narrowest width where the tapers 42, 43 of the through hole 5 b are connected to each other in the cross-sectional shape may be provided closer to the surface side than the center of the through hole 5 b in the thickness direction. Good. When the through hole 5b shown in FIG. 20 is formed, the taper 42 on the front surface side becomes inconspicuous when the direction from the front surface side to the back surface side of the key sheet 3 is viewed. In addition, when light is illuminated from the back surface side of the key sheet 3, the portion of the taper 43 from the back surface side of the through hole 5b is more efficiently condensed, so that characters and the like displayed in the through hole 5b are higher. Looks bright with brightness. Furthermore, there is an effect that the resin layer formed in the through hole 5b is difficult to be removed from the through hole 5b.

  Further, as shown in FIGS. 21 and 22, recesses, so-called counterbore portions 45 and 46, which extend on the outer periphery of the through holes 5 c and 5 d may be provided on the back surfaces of the through holes 5 c and 5 d. The counterbore portions 45 and 46 increase the surface area of the inner surface of the through holes 5c and 5d. Therefore, the first resin layers 8, 25 and 35 or the second resin layers 9, 26 and 36 and the through holes 5c and 5d Adhesion with the inner surface is improved. Therefore, the first resin layers 8, 25, 35 and the second resin layers 9, 26, 36 are hardly peeled off from the key sheet 3. Further, as shown in FIG. 22, a counterbore portion 46 is provided in the through hole 5d, and a taper 47 whose opening area decreases toward the surface is provided in a portion from the counterbore portion to the surface of the through hole 5d. Good. Thus, when the taper 47 illuminates from the back side of the key top 3, the taper 47 portion concentrates more efficiently, so that the characters and the like displayed in the through hole 5d appear to shine with higher brightness.

  Next, examples of the present invention will be described.

  In this example, using each test piece, (1) pinhole or crack occurrence rate, (2) adhesion strength between the metal key sheet and the base sheet, and (3) poor adhesion between the key sheet and the base sheet. Each rate was evaluated.

(Test piece preparation method)
As the key sheet 3, a 0.2 mm thick flat plate made of SUS304 was used. Further, in each test piece, the first resin layers 8, 25, and 35 were formed by dispensing a urethane acrylate UV curable resin. The second resin layers 9, 26, and 36 thinner than the first resin layers 8, 25, and 35 by screen printing using urethane-based two-component curable ink (product number “HAC”, manufactured by Seiko Advance Co., Ltd.). Was formed in the desired region. Moreover, after forming the 1st resin layer 8,25,35 and the 2nd resin layer 9,26,36, in the position which opposes the back surface of the key sheet 3, and a through-hole using a cyanoacrylate type adhesive agent. The adhesive layer 6 was provided at a plurality of locations. Next, a base sheet 7 made of thermoplastic urethane was attached to the key sheet 3 via the adhesive layer 6, and was attached to the back surface of the key sheet 3 by heating and pressing from the base sheet 7 side.

(Various evaluation methods)
(1) Method for evaluating pinhole or crack occurrence rate When pinholes or cracks are generated in the resin inside the through-hole 5, the applied adhesive is removed from the pinholes or cracks on the surface side of the key sheet 3. Therefore, the presence or absence of appearance defects due to the exposed adhesive was visually observed.

Judgment criteria A: When the defective product rate is 0/100 B: When the defective product rate is 1/100 or more

(2) Evaluation method of adhesive strength between metal piece and base sheet used for key sheet The adhesive strength between the key sheet 3 and the base sheet 7 was measured under the following conditions. The part of the key sheet 3 and the base sheet 7 were each gripped by a testing machine, pulled in a direction of peeling from each other at a speed of 60 mm / min, and the adhesive strength was determined from the tensile strength at the time of peeling. The test was performed three times, and the average value of the adhesive strength was obtained.

Judgment criteria A: average value of adhesive strength is 10 N / cm or more B: average value of adhesive strength is 5 N / cm or more and less than 10 N / cm C: average value of adhesive strength is 5 N / cm Less than

(3) Evaluation Method of Adhesion Failure Rate between Key Sheet and Base Sheet For a plurality of test pieces, the adhesive strength between the key sheet 3 and the base sheet 7 was measured by the same method as the method (2). The defective adhesion rate was evaluated from the incidence of test pieces having a measured adhesive strength of 10 N / cm or less.

A: When the occurrence rate of a test piece having an adhesive strength of 10 N / cm or less is 0/100 B: The occurrence rate of a test piece having an adhesive strength of 10 N / cm or less is 1 to 20/100 Case C: When the incidence of test pieces having an adhesive strength of 10 N / cm or less is 21/100 or more

  Next, performance evaluation results in each example will be described. Table 1 summarizes the evaluation results.

Example 1
The first resin layer 8 having a thickness of about 0.21 to 0.25 mm is formed on the inner surface side of the through hole 5, and the first resin layer 8 having a thickness of about 0.005 to 0.02 mm is formed on the inner back surface side of the through hole 5. Two resin layers 9 were formed, and the same one as the input sheet member 2 according to the first embodiment was produced. The appearance defect rate of the input sheet member 2 of Example 1 was extremely low, 0%. It is considered that this is because the sealing effect of the through hole 5 is improved by forming the second resin layer 9 in the portion of the through hole 5. However, the adhesive strength between the key sheet 3 and the base sheet 7 was not greatly improved.

(Example 2)
A second resin layer 26 having a thickness of about 0.005 to 0.02 mm covers the entire back surface of the key sheet 3 and is formed in a recess formed by the second resin layer 26 in a portion corresponding to the through hole 5. A first resin layer 25 having a thickness of about 0.18 to 0.25 mm was formed, and the same member as the input sheet member 20 according to the second embodiment was produced. That is, the second resin layer 26 closed the opening on the front surface side of the through hole 5 and covered the inner side surface of the through hole 5 and the back surface of the key sheet 3. The appearance defect rate of the input sheet member 20 of Example 2 was extremely low, 0%. Furthermore, in the input sheet member 20 of Example 2, the adhesive strength between the key sheet 3 and the base sheet 7 was improved. However, the incidence of test pieces having an adhesive strength of 10 N / cm or less remained in the range of 1 to 20%, and no significant decrease was observed.

(Example 3)
A first resin layer 35 having a thickness of about 0.21 to 0.25 mm is formed inside the through-hole 5 and is formed on the entire back surface of the key sheet 3 so as to fill the irregularities formed by the first resin layer 35. A second resin layer 36 having a thickness of about 0.03 to 0.06 mm was formed, and the same member as the input sheet member 30 according to the third embodiment was produced. In the input sheet member 30 of Example 3, the appearance defect rate was extremely low, and the adhesive strength between the key sheet 3 and the base sheet 7 was significantly improved. Further, no test piece having an adhesive strength of 10 N / cm or less was generated, and no adhesion failure was observed.

(Comparative example)
The key sheet 3 used was the same as in the above embodiments. Further, in each test piece, the same UV curable resin as the first resin layers 8, 25, and 35 in each example is used as the resin for filling the through hole 5, and the through hole 5 is filled by dispensing. did. In addition, after filling the through holes 5 with the UV curable resin, a plurality of adhesive layers 6 are provided on the back surface of the key sheet 3 and at positions facing the through holes 5 using a cyanoacrylate adhesive. Was applied to the key sheet 3 by heating and pressing. Although the comparative example is a member for an input sheet that can withstand practical use, since the through hole 5 is filled with only one kind of resin layer, the constituent component of the adhesive is from the pinhole or crack to the surface side of the key sheet 3 The appearance was poor, and poor appearance was observed. In the comparative example, the adhesive strength between the key sheet 3 and the base sheet 7 was relatively low.

  The present invention can be used for, for example, a push button switch as an input device of various electronic devices.

2, 20, 30, 2A, 2B, 2C, 2D, 20A, 20B, 20C Input sheet member 3 Key sheet (key assembly plate)
3a, 3b, 3c Key 5 Through-hole 6 Adhesive layer 8, 25, 35 First resin layer 9, 26, 36 Second resin layer (for example, printing layer)

Claims (7)

A key or key assembly plate having one or more through holes penetrating in the front and back direction;
A first resin layer formed in the through hole;
A second resin layer that is disposed at least in the depth direction of the through hole of the first resin layer and is thinner than the first resin layer at least in the region of the through hole;
An input sheet member comprising: The input sheet member according to claim 1,
The input sheet member, wherein the second resin layer is also formed on an inner surface of the through hole. The input sheet member according to claim 1 or 2,
The second resin layer is formed on the surface opposite to the operation surface of the key or the key assembly plate.
An input sheet member formed to cover the first resin layer and its periphery. The input sheet member according to claim 3,
The second resin layer is formed on a surface opposite to the operation surface of the key or the key assembly plate as a layer thicker than a height at which the first resin layer protrudes from the through hole. An input sheet member. The input sheet member according to any one of claims 1 to 4, wherein:
The input sheet member, wherein the second resin layer is a printing layer. The input sheet member according to any one of claims 1 to 5,
The input sheet member, wherein the through-hole is provided with a taper or a counterbore which changes a hole diameter in the depth direction. A method for manufacturing a member for an input sheet comprising a key or a key assembly plate having one or more through holes penetrating in the front-back direction,
A first resin layer forming step of forming a first resin layer in the through hole;
Before or after the formation of the first resin layer, the first resin layer is disposed at least in the depth direction of the through hole of the first resin layer at least in the region of the through hole and is thinner than the first resin layer. A second resin layer forming step of forming two resin layers;
The manufacturing method of the member for input sheets characterized by including these.

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