Key for keyboard device

Abstract

The technical problem to be solved by the present invention is to improve the bonding strength between wood and a resin material in a bond for bonding the wood and the resin material. A key for a keyboard device is provided with a wood key body part, a resin key upper surface part provided on the upper surface of the key body part, and an adhesive for bonding the key body part and the key upper surface part, a recess is provided on the lower surface of the key upper surface part, and a concave-convex shape is further formed inside the recess. The diameter of the recesses is 20 [mu] m or more and 500 [mu] m or less, and the height difference of at least a part of the uneven shape is 20 [mu] m or more.

Description

Technical Field

[0001] One embodiment of the present invention relates to a key for a keyboard device. Background Art

[0002] Generally, in keyboard devices such as acoustic pianos and electronic pianos, keys with resin materials attached to the upper surface of a key body made of wood, and keys with wood attached to the side of a key body made of resin are used (Patent Documents 1 and 2). If the attached resin material is peeled off from the wood, it will not only affect the appearance of the piano, but also cause difficulties for the user (player) to play, so it is necessary to prevent the peeling of the wood and the resin material.

[0003] Patent Document 1: JP2014-066816A

[0004] Patent document 2: JP2023-050818A Summary of the invention

[0005] Technical problem to be solved by the invention

[0006] In recent years, out of consideration for the environment, when bonding wood to resin materials, organic solvent-based (polyurethane-based) adhesives are no longer used, and water-soluble adhesives (e.g., wood glue) need to be used. However, the flatness of the surface of the resin material is very high, and the wood glue cannot enter the interior of the resin material, and thus cannot obtain sufficient bonding strength. As a result, interface damage will occur between the resin material and the adhesive, and there is a problem of the resin material peeling off from the wood. In the past, in order to improve the bonding strength of wood glue and resin materials, countermeasures such as filing processing and embossing processing performed by a mold were adopted on the surface of the resin material, but sufficient bonding strength could not be obtained.

[0007] One of the objects of one embodiment of the present invention is to improve the bonding strength between a wood material and a resin material in a bond between the two.

[0008] Technical solutions for solving technical problems

[0009] A key used in a keyboard device according to one embodiment of the present invention comprises: a key body portion made of wood; a key upper surface portion made of resin, which is arranged on the upper surface of the key body portion; an adhesive, which bonds the key body portion and the key upper surface portion; a recess is provided on the lower surface of the key upper surface portion, and a concave-convex shape is further formed inside the recess.

[0010] The diameter of the concave portion may be not less than 20 μm and not more than 500 μm, and the height difference of at least a part of the concavo-convex shape may be not less than 20 μm.

[0011] It may be that, on the lower surface of the key upper surface portion, there exists: a first portion which can be seen when observed from the key body portion; and a second portion which, when observed from the key body portion, is located at a position blocked by the first portion and cannot be seen.

[0012] A key used in a keyboard device according to one embodiment of the present invention comprises: a key body portion made of wood; a key upper surface portion made of resin, which is arranged on the upper surface of the key body portion; an adhesive, which bonds the key body portion and the key upper surface portion; on the lower surface of the key upper surface portion there are: a first part, which can be seen when observed from the key body portion; and a second part, which is located at a position blocked by the first part and cannot be seen when observed from the key body portion.

[0013] A recessed portion may be provided on the lower surface of the key upper surface portion, and the recessed and convex shape may be formed inside the recessed portion.

[0014] The adhesive may be a water-soluble adhesive.

[0015] The recessed portion may be provided in plurality, and the plurality of recessed portions may be periodically arranged in a plan view.

[0016] The concavo-convex shape may be provided on a portion of the lower surface of the key upper surface portion, and the lower surface of the key upper surface portion in the other portion may be flat.

[0017] The concavo-convex shape may be provided on a lower surface of the key upper surface portion corresponding to a region 3 mm or more from a front end of the key body portion.

[0018] A first region at the front end of the lower surface of the key upper surface portion may protrude from the front end of the key body portion, and the concavo-convex shape may not be formed on the lower surface of the key upper surface portion in the first region.

[0019] Effects of the Invention

[0020] According to one embodiment of the present invention, in a bond for bonding a wood material to a resin material, the bonding strength between the two can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a perspective view showing the appearance of a keyboard device in one embodiment of the present invention.

[0022] Figure 2 It is a side view showing the string-strike mechanism of the keyboard device in one embodiment of the present invention.

[0023] Figure 3 It is a side view of a key in one embodiment of the present invention and an enlarged view of a part thereof.

[0024] Figure 4 yes Figure 3 A partial enlarged view of the dotted box.

[0025] Figure 5 yes Figure 4 A partial enlarged view of the dotted box.

[0026] Figure 6 It is a diagram showing a laser irradiated portion of an upper surface member of a key in one embodiment of the present invention.

[0027] Figure 7 This is a partially enlarged view of a laser irradiated portion of the upper surface material of the key in one embodiment of the present invention.

[0028] Figure 8 This is a cross-sectional view of a laser irradiated portion of an upper surface member of a key in one embodiment of the present invention.

[0029] Fig. 9 This is a partially enlarged view of a laser irradiated portion of an upper surface member of a key in a modified example of one embodiment of the present invention.

[0030] Fig.10 It is a diagram showing a laser irradiated portion of the upper surface material of a key in a modified example of one embodiment of the present invention.

[0031] Fig.11 It is a perspective view of a key in a modified example of one embodiment of the present invention.

[0032] Description of Reference Numerals

[0033] 10: keyboard device, 100: white key, 110: key body, 120: key upper surface, 121: recess, 122: concave-convex shape, 123: concave shape, 124: convex shape, 125: concave-convex forming area, 126: front end, 127: edge, 128: plane shape, 129: upper part, 130: key front surface, 150: adhesive layer, 200: pedal, 300: string striking mechanism, 400: hammer, 500: string, 600: damper, 700: damper action mechanism, 800: limit stop, 810: key sensor, 820: hammer sensor, 900: white key, 910: key body, 920: key side surface, P0: interval, PV: height difference, R1: area, R2: area, TP: protrusion, W: width. DETAILED DESCRIPTION

[0034] Hereinafter, the keys for the keyboard device of one embodiment of the present invention will be described in detail with reference to the accompanying drawings. The embodiment shown below is an example of a form implemented by the present invention, and the present invention should not be construed as being limited by these embodiments. In the drawings referred to in the present embodiment, there are cases where the same parts or parts with the same functions are marked with the same figure mark or similar figure mark, and their repeated description is omitted. For the convenience of explanation, there are cases where the dimensional ratios of the drawings (the ratios between the various structures, the ratios in the vertical and horizontal height directions, etc.) are different from the actual ratios, and there are also cases where part of the structure is omitted from the drawings. In the following description, based on the up and down directions in each drawing, there are cases where they are expressed as "up", "above", "upper end", "down", "below", and "lower end", but these up and down directions are only for explanation of the relative direction relationship, and the up and down directions can also be reversed.

[0035] [1. Overall Structure of Keyboard Device 10]

[0036] Figure 1 1 is a perspective view showing the appearance of a keyboard device 10 in one embodiment of the present invention. The keyboard device 10 has a keyboard having a plurality of keys 100 arranged therein and a pedal 200. The keys 100 and the pedal 200 are provided on the front surface of the keyboard device 10. A performer performs a musical performance by operating the keys 100 and the pedal 200. Figure 1 In the embodiment, a grand piano is shown as an example of the keyboard device 10, but the keyboard device 10 of the present embodiment is not limited to a grand piano, and may be an upright piano or an electronic keyboard. The keyboard device 10 has a plurality of pedals, and the pedal 200 is a damper pedal.

[0037] Figure 2 1 is a side view showing a striking mechanism of a keyboard device according to one embodiment of the present invention. Figure 2 In the embodiment, among the multiple keys 100 provided in the keyboard device 10, the structure of one white key 100 is exemplified. The other white keys and black keys also have the same Figure 2 The same structure is omitted. Figure 2 As shown, the keyboard device 10 includes white keys 100 , a string action mechanism 300 , hammers 400 , strings 500 , dampers 600 , and a damper actuation mechanism 700 .

[0038] The striking mechanism 300 and the hammer 400 are provided corresponding to each white key 100. When the white key 100 is pressed, the force is transmitted through the striking mechanism 300, and the hammer 400 moves to strike the string 500 provided corresponding to the white key 100. The string 500 is a sound-generating body that produces sound due to the strike from the hammer 400. When the string 500 is struck, the string 500 vibrates at a vibration frequency corresponding to each white key 100. The damper 600 is moved by the damper action mechanism 700. The damper action mechanism 700 controls the contact state or non-contact state of the damper 600 and the string 500 according to the amount of depression of the white key 100 and the amount of stepping on the pedal 200. When the damper 600 contacts the string 500, the vibration of the string 500 stops and the sound generation stops.

[0039] In addition to the above-mentioned components, the keyboard device 10 is also provided with a limit stopper 800, a key sensor 810, and a hammer sensor 820. The limit stopper 800 is a component that collides with the hammer handle and limits the upward rotation of the hammer 400. The key sensor 810 is arranged at the lower part of the white key 100, and outputs a detection signal corresponding to the movement of the white key 100 to the control device. For example, the key sensor 810 detects the pressing amount of the white key 100 as a continuous amount (fine resolution), and outputs a detection signal indicating the detection result to the control device. The hammer sensor 820 is arranged corresponding to each hammer 400, and outputs a detection signal corresponding to the movement of the hammer 400 to the control device. For example, the hammer sensor 820 detects the moving speed of the hammer 400 before hitting the string 500, and outputs a detection signal indicating the detection result to the control device. The control device determines the striking timing (key-on timing) and striking speed (speed) of the hammer 400 on the string 500 in correspondence with each white key 100 (key number) based on the detection signals from the key sensor 810 and the hammer sensor 820 .

[0040] [2. Key structure]

[0041] Figure 3 1 is a side view of a key in one embodiment of the present invention and an enlarged view of a portion thereof. Figure 3 As shown, the white key 100 has a key body 110, a key upper surface 120, and a key front surface 130. The key body 110 is made of wood, and the key upper surface 120 and the key front surface 130 are made of resin. The key upper surface 120 is provided on the upper surface of the key body 110. The key front surface 130 is provided on the front surface (end surface in the D1 direction) of the key body 110. The key upper surface 120 and the key front surface 130 are bonded to the key body 110 using a water-soluble adhesive such as a vinyl acetate resin emulsion adhesive (wood glue).

[0042] The thickness of the key upper surface portion 120 and the key front surface portion 130 is greater than 1 mm and less than 3 mm, or greater than 1.5 mm and less than 2.0 mm. Therefore, there are limitations on the method of performing convexoconcave processing on the key upper surface portion 120 and the key front surface portion 130. For example, acrylic resin (PMMA resin), ABS resin, AS resin and unsaturated polyester resin can be used as the key upper surface portion 120 and the key front surface portion 130. The key upper surface portion 120 and the key front surface portion 130 can be the same component or different components. For example, PMMA resin can be used as the key upper surface portion 120, and ABS resin can be used as the key front surface portion 130.

[0043] The key upper surface portion 120 extends across the front end (the end in the D1 direction) of the key body portion 110 and protrudes in the D1 direction compared to the key front surface portion 130. This protruding portion is sometimes referred to as a protruding portion TP. The amount by which the protruding portion TP protrudes from the front surface (the surface on the D1 direction side) of the key front surface portion 130 is greater than 1 mm and less than 5 mm or greater than 1.5 mm and less than 3 mm.

[0044] like Figure 3 As shown in the partially enlarged view (A) of , an adhesive layer 150 is provided between the key body portion 110 and the key upper surface portion 120. The adhesive layer 150 is in contact with the lower surface of the key upper surface portion 120. The adhesive layer 150 is a water-soluble adhesive. For example, as the adhesive layer 150, wood glue can be used as described above. Wood glue is a water-soluble adhesive having vinyl acetate resin as a component. The moisture contained in the wood glue is absorbed or evaporated by the wood, so that the wood glue solidifies. The wood is porous, and very complex concave-convex shapes are formed on its surface. When a water-soluble adhesive is used in bonding the wood, the water-soluble adhesive solidifies in a state of entering the interior of the concave-convex shapes of the wood. Therefore, the water-soluble adhesive provides a stronger adhesive force to the wood. On the other hand, the surface of the resin material is flat, so the water-soluble adhesive cannot enter the interior of the resin material. Therefore, the water-soluble adhesive cannot provide a stronger adhesive force to the resin material.

[0045] Figure 4 yes Figure 3 The enlarged view of the dotted box (B). Figure 4As shown, a plurality of recesses 121 are provided on the lower surface of the key upper surface portion 120. The width W of the recess 121 is greater than 20 μm and less than 500 μm, greater than 50 μm and less than 300 μm, greater than 50 μm and less than 200 μm, or greater than 75 μm and less than 150 μm. The depth of the recess 121 is greater than 20 μm, greater than 30 μm, or greater than 40 μm. The recesses 121 are periodically arranged at intervals P0. The periodicity of the recess 121 can be evaluated by performing Gaussian fitting on the shape of the recess 121 and measuring the distance between the vertices of the fitted curve. A concave-convex shape is further formed inside the recess 121. The concave-convex shape will be described in detail later.

[0046] The area on the lower surface of the key upper surface 120 where the recess 121 is not provided (the area far enough from the recess 121) is flat, which will be described in detail later. The depth of the recess 121 is based on the flat surface on the lower surface of the key upper surface 120. Figure 4 In the case where the adjacent recesses 121 are formed, the recesses 121 may be convex downward. Therefore, when evaluating the depth of the recesses 121, the evaluation is performed based on the flat lower surface of the key upper surface portion 120 as described above.

[0047] Figure 5 yes Figure 4 A partial enlarged view of the dotted box (C). Figure 5 The enlarged view shown is Figure 4 FIG. 1 is an enlarged view of a portion of the concave portion 121. Figure 4 In the figure, for the convenience of explanation, the interior of the recess 121 is represented by a smaller step, but in fact Figure 5 As shown, a concave-convex shape 122 with a large step is formed inside the concave portion 121. For example, the height difference PV of at least a part of the concave-convex shape 122 is greater than 20 μm. Figure 5 As shown, the concavo-convex shape 122 formed inside the concave portion 121 is not arranged periodically like the concave portion 121, but is arranged irregularly.

[0048] exist Figure 5 In the partial enlarged view (D), a concave shape 123 and a convex shape 124 in the concave-convex shape 122 are enlarged. Figure 5As shown, an undercut shape is formed by a concave shape 123 and a convex shape 124. That is, in the key upper surface portion 120 in the concave shape 123, there is a region R1 that can be seen when observed from below (when observed from the key body portion 110 side) and a region R2 that cannot be seen. By having such a shape, even if the adhesive layer 150 is subjected to an external force in a direction in which the adhesive layer 150 leaves the key upper surface portion 120, the adhesive layer 150 formed in the region R2 is stuck to the convex shape 124, and therefore, it is possible to suppress the adhesive layer 150 from peeling off from the key upper surface portion 120. That is, the adhesive layer 150 is firmly bonded to the key upper surface portion 120 by the anchoring effect of the undercut shape. In the key upper surface portion 120, the portion in the region R1 can be referred to as the "first portion", and the portion in the region R2 can be referred to as the "second portion".

[0049] The lower surface of the key upper surface portion 120 is provided with a plurality of undercut shapes similar to the concave shape 123 and the convex shape 124. Each of the plurality of undercut shapes exerts an anchor effect, thereby improving the bonding strength between the adhesive layer 150 and the key upper surface portion 120.

[0050] [3. Method for forming recessed portion 121 and concavo-convex shape 122]

[0051] Figure 4 and Figure 5 The formation of the recessed portion 121 and the concavo-convex shape 122 shown is achieved by laser irradiating the lower surface of the key upper surface portion 120 with a low output. The output of the laser used in the laser irradiation can be, for example, 1 W or more and 100 W or less, 5 W or more and 50 W or more, or 10 W or more and 20 W or less. As a laser irradiation device, a device that continuously irradiates the laser can be used, and a device that periodically irradiates the laser can also be used. In the case of using a laser irradiation device that periodically irradiates the laser, for example, the laser can be irradiated at a period corresponding to a frequency of 10 kHz or more and 50 kHz or 20 kHz or more and 30 kHz or less. The scanning speed of the laser in this case can be 500 mm / sec or more and 3000 mm / sec or more, or 1000 mm / sec or more and 2200 mm / sec or less.

[0052] For example, in a laser irradiation device for processing metal, the output of the laser is greater than 100 W. However, when such a high-output laser device is used to process a resin material such as the key top surface portion 120, the resin in the area irradiated by the laser completely melts or carbonizes, and thus no Figure 5Therefore, in the present embodiment, in order to obtain the undercut shape, the key upper surface portion 120 is irradiated with laser light at an output in the above numerical range. As such a laser irradiation device, a laser marking device can be used. In order to cut or melt only the outermost layer of the processing object part, the laser marking device irradiates laser light at an output that is very weak compared to the laser irradiation device for processing.

[0053] In the conventional filing and embossing processes, only a concave shape with a forward taper is formed, and it is impossible to obtain Figure 5 As described above, even if the output of the laser is reduced in the laser irradiation device for processing, the undercut shape cannot be obtained. However, by using a laser marking device that has a smaller output than the laser irradiation device for processing and processes only the outermost layer of the object, as described above, an undercut shape can be formed on the lower surface of the key upper surface portion 120. By forming the undercut shape, the bonding strength between the key upper surface portion 120 and the adhesive layer 150 can be improved.

[0054] [4. Concavoconvex forming area 125]

[0055] Figure 6 1 is a diagram showing a laser irradiation portion of the upper surface of a key in one embodiment of the present invention. Figure 6 As shown, a concavo-convex formation region 125 is provided near a front end 126 of the key upper surface portion 120 in the D1 direction. Figure 4 and Figure 5 The recessed portion 121 and the concavo-convex shape 122 are shown. The concavo-convex forming region 125 is provided only in the region along the front end 126 of the key upper surface portion 120.

[0056] exist Figure 6 In the figure, the area closer to the front end 126 than the dotted line indicated near the front end 126 is the area of ​​the key upper surface portion 120 protruding in the D1 direction compared to the key body portion 110. The concave-convex forming area 125 is provided closer to the D2 direction side than the dotted line. The concave-convex forming area 125 is provided more than 3 mm closer to the D2 direction side than the dotted line. That is, the distance between the end of the concave-convex forming area 125 in the D1 direction and the front end 126 is more than 3 mm. Figure 3 As shown, a portion of the lower surface of the key upper surface portion 120 is exposed to the outside, but the recessed portion 121 and the concavo-convex shape 122 cannot be formed in the region exposed to the outside.

[0057] like Figure 3As shown, the vicinity of the front end of the key upper surface portion 120 protrudes in the direction D1. Therefore, there is a case where the finger of the user who is playing contacts the vicinity of the front end of the key upper surface portion 120. In particular, when the finger of the user collides with the vicinity of the front end of the key upper surface portion 120 from below, a force in the direction of peeling the key upper surface portion 120 from the key body portion 110 acts on the key upper surface portion 120 due to the collision. However, a concave-convex forming area 125 is provided near the front end of the key upper surface portion 120, and even if such a force acts on the key upper surface portion 120, it is possible to suppress the key upper surface portion 120 from peeling off from the key body portion 110.

[0058] Figure 7 This is a partially enlarged view of a laser irradiated portion of the upper surface member of a key in one embodiment of the present invention. Figure 7 Yes Figure 6 FIG. 1 is an enlarged view of a portion of the concavo-convex formation area 125. Figure 7 As shown, in the concavo-convex forming region 125, a plurality of concave portions 121 are periodic when viewed from above. Figure 7 In the example shown, the plurality of recesses 121 are arranged at equal intervals in the D1 direction and the D3 direction, but the interval between adjacent recesses 121 in the D1 direction and the interval between adjacent recesses 121 in the D3 direction may be different. The cross-sectional shape of each of the plurality of recesses 121 is similar to Figure 4 and Figure 5 Same shape.

[0059] Figure 8 This is a cross-sectional view of a laser irradiated portion of an upper surface member of a key in one embodiment of the present invention. Figure 8 The cross-sectional view shown is along Figure 7 It should be noted that: Figure 8 The cross-sectional view shown is simplified for ease of explanation, but the actual cross-sectional shape is different from Figure 4 and Figure 5 The cross-sectional views shown are the same. Figure 8 In the description, the shape of the edge of the recess 121 and the shape of the outer side of the recess 121 are mainly described.

[0060] like Figure 8 As shown, the edge 127 of the recess 121 protrudes downward. The edge 127 is provided around the recess 121. When the recess 121 is formed by laser irradiation, the protruding shape at the edge 127 is formed by the movement of the resin material originally present in the recess 121. In the area further outside than the edge 127, the lower surface of the key upper surface portion 120 is flat. In other words, a part of the lower surface of the key upper surface portion 120 is provided with a concavo-convex shape, and the lower surface of the key upper surface portion 120 is flat in other parts.

[0061] As described above, the white key 100 of this embodiment can improve the bonding strength between the wood (key body 110) and the resin material (key upper surface 120) even when a water-soluble adhesive (adhesive layer 150) is used for bonding. It should be noted that, even when an organic solvent system is used as the adhesive layer 150, the bonding strength with the resin material can be improved by the undercut shape.

[0062] [5. Modifications]

[0063] use Figures 9 to 11 Modifications of this embodiment will be described. Fig. 9 FIG. 1 is a partial enlarged view of the laser irradiation portion of the upper surface part of the key in one embodiment of the present invention. Fig. 9 In, with Figure 7 The difference is that adjacent recesses 121 overlap when viewed from above. Fig. 9 As shown in FIG. 1 , when adjacent concave portions 121 overlap, the concave portions 121 can actually be regarded as a continuous shape like the planar shape 128. In this case, the concave portions 121 are periodically arranged based on the local periodic shape. Specifically, it can be determined that the concave portions 121 are periodically arranged based on the local periodic shape. Fig. 9 The upper portions 129 of the plurality of overlapping recesses 121 are shown to be periodically arranged.

[0064] Fig.10 1 is a diagram showing a laser irradiated portion of an upper surface part of a key in one embodiment of the present invention. Fig.10 In, with Figure 6 The difference is that the concavo-convex forming area 125 is not only provided near the front end 126 of the key upper surface portion 120, but also provided along the periphery of the key upper surface portion 120. Fig.10 As shown, the concavo-convex forming region 125 may be provided continuously along the circumference of the key upper surface portion 120 , or may be provided discretely along the circumference.

[0065] Fig.11 It is a perspective view of a key in a modified example of one embodiment of the present invention. Fig.11 The white key 900 shown may be, for example, a white key for an electronic piano. The key body 910 of the white key 900 may be made of a resin material, and the key side surface 920 may be made of wood. The key body 910 may be integrally formed by resin molding, and a recess is formed on its side. The key side surface 920 may be a plate-like wood, which is bonded in a manner of being embedded in the recess of the key body 910.

[0066] Even with such a structure, by forming the key main body 910 made of resin material with Figure 4 and Figure 5The recessed portion 121 and the concavo-convex shape 122 shown in the figure have the same shape, and can improve the bonding strength between the key body portion 910 and the key side portion 920 .

[0067] In the above-mentioned modified examples, the same effects as those of the present embodiment can be obtained.

[0068] It should be noted that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the spirit and scope of the present invention.

Claims

1. A key for a keyboard device, characterized in that have: Key body of wood; A key upper surface portion made of resin, which is provided on the upper surface of the key main body portion; an adhesive bonding the key body portion to the key upper surface portion; A recess is provided on the lower surface of the key upper surface. A concavo-convex shape is further formed inside the concave portion.

2. The key according to claim 1, The diameter of the concave portion is not less than 20 μm and not more than 500 μm, The height difference of at least a part of the concavo-convex shape is 20 μm or more.

3. The key according to claim 2, On the lower surface of the key upper surface portion there are: a first portion that can be seen when viewed from the key body; The second portion is located at a position blocked by the first portion and cannot be seen when viewed from the key body.

4. A key for a keyboard device, characterized in that: have: Key body of wood; A key upper surface portion made of resin, which is provided on the upper surface of the key main body portion; an adhesive bonding the key body portion to the key upper surface portion; On the lower surface of the key upper surface portion there are: a first portion that can be seen when viewed from the key body; The second portion is located at a position blocked by the first portion and cannot be seen when viewed from the key body.

5. The key according to claim 4, A recess is provided on the lower surface of the key upper surface portion, A concavo-convex shape is formed inside the concave portion.

6. A key according to any one of claims 1 to 5, The adhesive is a water-soluble adhesive.

7. A key according to any one of claims 1 to 3, The recess is provided with a plurality of The plurality of recesses are periodically arranged in a plan view.

8. A key according to any one of claims 1 to 3 and 5, The concavo-convex shape is provided on a part of the lower surface of the key upper surface portion, and the lower surface of the key upper surface portion in the other part is flat.

9. A key according to any one of claims 1 to 3 and 5, The concavo-convex shape is provided on the lower surface of the key upper surface portion corresponding to a region which is 3 mm or more from the front end of the key body portion.

10. The key according to claim 9, A first area at the front end of the lower surface of the key upper surface portion protrudes from the front end of the key body portion, and the concavo-convex shape is not formed on the lower surface of the key upper surface portion in the first area.

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