JP2005317475A - Key sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a key sheet for a push button switch, a key top of which is not detached from a gear. <P>SOLUTION: The key sheet comprises: a base sheet 5 made of a rubber-like elastic body; a key top 4 having a lock groove 4e on the side; and a stopper 6, which is set on the base sheet 5 and has a through-hole 6b, where the key top 4 penetrates through the through-hole 6b, a brim of the through-hole 6b enters into the lock groove 4e, and the stopper 6 is locked with the lock groove 4e in a direction away from the key top to the base sheet 5. Therefore, even if the key top 4 is going to be detached from a case 2, the lock groove 4e of the key top 4 is locked at the brim of the through-hole 6b of the stopper 6, and the key top 4 can be kept from detaching. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a key sheet for a push button switch used in an operation unit of various devices such as a mobile phone, a PDA, a car navigation device, and a car audio device.

A device such as a cellular phone as described above is equipped with a key sheet for a push button switch, and the key sheet is pressed by a base sheet made of a rubber-like elastic body placed on a printed circuit board and the base sheet. And a key top that is floatably supported so as to be displaceable, and the key top is fixed to the base sheet via an adhesive layer. In such a key sheet, when a pressing operation is applied to the key top exposed from the casing of the device, the base sheet is elastically deformed in the pressing operation direction, and the contact switch of the printed circuit board is turned on / off, so that the switch input (Patent Document 1).
JP2004-111258A

  By the way, in such a key sheet, due to a request for thinning on the side of a device on which the key sheet is mounted, studies have been made in the direction of making the base sheet as thin as possible. However, if the base sheet is made thinner (thinner), the durability of the base sheet is reduced. If the key top is repeatedly pressed and displaced, the base sheet breaks due to repeated elastic deformation, and the key top becomes the housing of the device. There is a risk of detachment.

  The present invention has been made against the background of the prior art as described above. The object is to provide a key sheet for a push button switch in which the key top does not detach from the device.

  In order to achieve the above object, a key sheet of the present invention includes a base sheet made of a rubber-like elastic body, a key top provided with a locking groove on a side surface, and a transparent material that is placed on the base sheet and penetrates through the key top. A detachment restricting member that has a hole, the hole edge of the through hole enters the locking groove of the key top, and locks the locking groove in the direction in which the key top is separated from the base sheet. The

  According to this, even if the key top is about to be detached from the device, the key top locking groove is locked to the hole edge of the through hole of the removal regulating member, so that the key top can be held without being detached. Can do.

  Since the key top does not detach from the device in this way, the present invention does not fix the key top to the base sheet as well as the key sheet configured to be fixed to the base sheet via, for example, an adhesive layer. It can also be configured as a key sheet of configuration.

  Specifically, the key top in the present invention can be configured as a separate upper key top and lower key top that are separated vertically from each other with a locking groove as a boundary. According to this, it is possible to attach the key top to the through hole of the drop-off restricting member in a penetrating state.

  The key top in the present invention can be configured as an integral molded body that cannot be separated unless the material is cut or broken. According to this, the adhering process of the upper and lower key tops can be omitted. In this case, the key top and the detachment regulating member can be combined by, for example, insert molding.

  The key top according to the present invention can be configured as a top key top formed of a transparent resin, having a flat bottom surface, and a decorative print layer for decorating the upper key top on the bottom surface. According to this, since there is a decorative print layer on the bottom surface of the upper key top, there is no inconvenience that the decorative print layer is worn by a pressing operation on the key top and the display disappears.

  The key top in the present invention can be configured by forming a decorative printing layer for decorating the key top on the top surface of the key top and forming a protective layer made of a transparent resin thereon. According to this, since the decorative printed layer is protected by the protective layer, there is no inconvenience that the decorative printed layer is worn by the pressing operation on the key top and the display disappears.

  The key top in the present invention can be configured as having an insertion recess in one of the upper key top and the lower key top and having an insertion projection on the other. According to this, the upper key top and the lower key top can be fixed by an adhesive or the like without being displaced.

  The key top in the present invention is configured such that a reservoir groove for excess adhesive is formed in either the insertion recess or the insertion protrusion. According to this, it can suppress that an adhesive agent protrudes from the adhesion surface of an upper key top and a lower key top to the outer surface of a key top, and the external appearance of a key top is not impaired.

  The present invention is configured such that the key top is fixed to the base sheet via the molded fixing portion. According to this, since the base sheet does not exist under the key top, the overall height of the key sheet can be reduced with respect to the thickness of the base sheet. Further, in the case of a basic configuration in which the key top is fixed to the base sheet, the key top bonding process can be eliminated.

  In the present invention, the base sheet may be configured to have a holding portion that wraps around the surface of the detachment regulating member and holds the detachment regulating member on the front and back sides. According to this, floating of the detachment restricting member with respect to the base sheet can be suppressed, and handling at the time of attachment to the device can be improved.

  The holding portion can be configured to hold the outer peripheral surface of the detachment regulating member over the entire circumference. According to this, the waterproof structure with respect to the inside of an apparatus is obtained by the holding part which consists of a rubber-like elastic body.

  The present invention can be configured such that the detachment regulating member is fixed to the base sheet via an adhesive layer. According to this, a flexible base sheet can be reinforced with a rubber-like elastic body. Moreover, the handleability at the time of attachment to an apparatus etc. can be improved.

  In the present invention, the through hole of the detachment restricting member has a gap between the key top locking groove and the key top so as not to cause a lateral displacement of the key top with respect to the key top pressing operation shaft. Formed as. According to this, the lateral displacement of the key top can be regulated such that accurate switch input by the key top is impaired by the through hole of the detachment regulating member. Even if the base sheet breaks, the key top is held by the detachment regulating member without shifting the pressing operation shaft, and can be used as it is for switch input.

  The present invention can be configured such that the hole edge of the through hole on the back surface of the detachment regulating member comes into contact with the locking groove in the key top pressing direction. The hole edge of the through hole on the back surface of the detachment regulating member abuts against the locking groove in the key top pressing operation direction, thereby preventing the key top from being tilted unnecessarily with respect to the pressing operation direction. Can be suppressed.

  In the present invention, the detachment regulating member can be formed of any one of a hard resin plate, a resin film, and a metal plate. According to these hard materials, it is possible to securely prevent the detachment by securely locking to the locking groove of the key top.

  The present invention may be configured to include a plurality of the key tops and a connecting portion that spans between the key tops as an integrated molded body. According to this, since the key tops are not separated one by one, handling at the time of manufacturing the key sheet is good and productivity can be improved.

  The present invention can be configured such that a plurality of the key tops are arranged narrowly on a base sheet so as to be exposed from an operation opening without a partition rail formed in a housing of the device. If the key top is partitioned by a partition bar formed on the casing of the device, when the casing of the device is downsized, the top of the key top also has to be reduced. However, according to the present invention, even if the housing of the device is downsized, the top surface, which is the operation surface of the key top, can be kept large because there is no partition rail. The present invention can also be applied to such a narrow key sheet, and can prevent the key top from being detached. Of course, the present invention can also be applied as a key sheet in which a plurality of the key tops are separated by a partition bar formed in a casing of the device.

  According to the present invention, since the key top is held by the detachment regulating member without being detached from the device, it is possible to prevent the key top from being lost or accidentally swallowing the detached key top.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, about the structure which is common in each embodiment, the same code | symbol is attached | subjected and duplication description is abbreviate | omitted.

First Embodiment [FIGS. 1 to 3] FIG. 1 is an external view of a cellular phone 1 exemplified as “apparatus”, and a key sheet 3 for a pushbutton switch according to the present embodiment is mounted on a housing 2 thereof. Is done. The key sheet 3 includes a key top 4, a base sheet 5, and a stopper 6 as a “detachment regulating member”.

  The key top 4 is narrowly disposed on the base sheet 5 in a state of being exposed from a single operation opening 2 a opening in the housing 2. The adjacent interval between the key tops 3 arranged narrowly is narrow, and is set to an interval of about 0.05 mm to 0.5 mm. Note that the distance from the operation opening 2a is about the same.

  Each key top 4 includes an upper key top 4 a and a lower key top 4 b, and both the key tops 4 a and 4 b are fixed via an adhesive layer 7. The upper key top 4a is a molded body in which a transparent resin is formed in a rectangular plate shape, and a decorative print layer 8 is formed on the bottom surface by printing characters, numbers, etc., and is visible from the outside. It has become. The lower key top 4b is a molded body in which a transparent resin is formed in a rectangular convex shape, and includes a protrusion 4c and a locking flange 4d protruding outward from the lower end of the protrusion 4c. The bottom surface of the locking flange 4 d is fixed to the base sheet 5 via the adhesive layer 9. The key top 4 formed by fixing the upper key top 4a and the lower key top 4b is formed with a locking groove 4e on the entire side thereof. That is, the locking groove 4e is formed by a concave portion formed by the bottom surface of the upper key top 4a, the outer peripheral surface of the protrusion 4c of the lower key top 4b, and the upper surface of the locking flange 4d of the lower key top 4b. The

  The base sheet 5 is formed of a rubber-like elastic body such as a thermosetting elastomer such as silicone rubber or a thermoplastic elastomer. The base sheet 5 is formed with a thick non-actuating part 5a to be placed on the printed circuit board P and a thin flexible actuating part 5b that is float-supported by the non-actuating part 5a. As described above, the lower key top 4b having an area smaller than that of the flexible operation portion 5b is fixed to the flexible operation portion 5b through the adhesive layer 9. Therefore, when the key top 4 is pressed, the non-bonded portion of the lower key top 4b in the flexible operating portion 5b is elastically deformed, and the switch input by the contact switch Pa of the printed circuit board P is performed by the pusher 5c displaced downward. It will be. The contact switch Pa is composed of a metal disc spring and a circuit contact of the substrate circuit.

  The stopper 6 is formed as a molded body of a hard material, in this embodiment, a hard resin, and is configured as a single plate as shown in FIG. 3 in this embodiment. The stopper 6 is formed with a receiving groove 6a for receiving the locking flange 4d of the lower key top 4b and a through hole 6b for inserting the protrusion 4c of the lower key top 4b. The hole edge of the through hole 6b is formed thin to form the receiving groove 6a, and the thin hole edge part enters the locking groove 4e of the key top 4 described above. Therefore, even if the key top 4 is about to be detached in the direction away from the base sheet 5 due to, for example, the flexible operating portion 5b of the base sheet 5 being broken, the locking flange 4d is located at the hole edge of the through hole 6b of the stopper 6. Abut and lock against. Thereby, the key top 4 is held so as not to be detached.

  The through hole 6b is formed so that there is almost no gap with respect to the outer peripheral surface of the protrusion 4c of the lower key top 4b. Therefore, the key top 4 is not displaced in the lateral direction, and an accurate switch input can be made by always pressing the contact switch Pa by the key top 4. Further, even when the flexible operating portion 5b of the base sheet 5 is broken by repeated pressing operations, the key top 4 is held by the through holes 6b without shifting the pressing operation shaft. Accurate switch input is possible even in the state.

  The remaining part of the stopper 6 excluding the housing groove 6 a is formed as a thick part placed on the base sheet 5. Therefore, the base sheet 5 is covered and reinforced by the hard resin stopper 6 over almost the entire surface, and the key sheet 3 is distorted even if the mobile phone 1 is tilted or tilted. There is no problem. The thick portion of the stopper 6 may be fixed between the housing 2 and the printed circuit board P even if it is fixed to the base sheet 6 via an adhesive layer or not. Any structure may be used as an attachment structure that holds the pressure.

Second Embodiment [FIG. 4] : The second embodiment is a modification of the first embodiment. The difference from the first embodiment is that the locking flange 4d of the lower key top 4b is formed thicker than the first embodiment, and the hole edge ( The locking groove 4e) is configured to contact the locking flange 4d without any gap. As described above, there is an advantage that the wobbling in the direction in which the key top 4 is tilted can be eliminated by contacting the locking flange 4d with the hole edge of the through hole 6b of the stopper 6 without a gap. In addition, when the hole edge is not only in contact with the locking flange 4d but also in a pressing contact structure, it is possible to further suppress an unnecessary inclination of the key top 4.

Third Embodiment [FIG. 5] : The third embodiment is a modification of the first embodiment. The difference from the first embodiment is that, as shown in FIG. 5A, a holding portion 5 d that holds the stopper 6 on the front and back is formed over the entire outer periphery of the base sheet 5. As a result, the stopper 6 can be held integrally with the base sheet 5, so that the handleability when the key sheet 3 is attached can be improved. Further, the front and back surfaces of the entire circumference (see FIG. 3) of the stopper 6 are covered with the holding portion 5d, and the holding portion 5d is in elastic contact with the back surface of the rim of the operation opening 2a of the housing 2. Thus, a waterproof structure is formed, and water droplets can be prevented from entering the inside of the housing 2 from the operation opening 2a.

  The holding part 5d can be configured not to hold the outer periphery of the stopper 6 over the entire circumference but to hold it partially. Further, as shown in FIG. 5B, instead of the outer periphery of the stopper 6, a retaining hole 6 c is formed at an in-plane position of the stopper 6, and the structure that is engaged with the stopper 6 through the surface is retained. It can also be configured as part 5e.

4th Embodiment [FIG. 6] : 3rd Embodiment differs from 1st Embodiment about the structure of the stopper 10 which makes a "detachment | desorption control member." The stopper 10 of the present embodiment is a metal plate such as a flat hard resin film or a stainless steel plate with no irregularities. For this reason, as shown in FIG. 6 (A), the base sheet 5 has an attachment protrusion 5f formed on the outer periphery, and the outer peripheral edge of the back surface of the stopper 10 is placed on the attachment protrusion 5f. Alternatively, it is fixed via an adhesive layer (not shown).

  FIG. 6A shows an example in which the stopper 10 is fixed to the base sheet 5. However, for example, as shown in FIG. 6B, the stopper 10 can be fixed to the housing 2 side. That is, the groove-like insertion part 2b can be formed in the housing | casing 2, and the outer end part of the stopper 10 can be inserted and fixed there. In this case, the insertion part 2b can be configured so that it can be inserted over the entire periphery of the stopper 10 or partially. Moreover, it can also be set as the structure fixed to the back surface of the housing | casing 2 only through an adhesive layer (not shown).

Fifth Embodiment [FIGS. 7 and 8] : In the fifth embodiment, the configurations of the key top 11 and the base sheet 12 are different from those of the above embodiments, and the stopper 10 is the same as that of the fourth embodiment.

  The key top 11 includes an upper key top 11a and a lower key top 11b. In the present embodiment, these are fixed to each other by ultrasonic fusion. Specifically, as shown in FIG. 8A, the upper key top 11a and the lower key top 11b before ultrasonic welding are respectively provided with a concave portion 11c and a projection 11d for fusion and positioning, and a tool horn. A plurality of positions are formed at positions on the circumference of the tip of H. The base sheet 12 is also formed with through holes 12a at positions corresponding to the recesses 11c and the protrusions 11d.

  Then, the tool horn H is lowered from the state of FIG. 8A, and as shown in FIG. 8B, the tip is pressed against the lower key top 11b through the through hole 12a to perform ultrasonic fusion. . As a result, the key top 11 to which the upper key top 11a and the lower key top 11b are fixed as shown in FIG. 7 is obtained. According to the present embodiment, the upper key top 11a and the lower key top 11b can be firmly fixed.

Sixth Embodiment [FIG. 9] : The sixth embodiment is characterized in that the lower key top 13b of the upper key top 13a and the lower key top 13b constituting the key top 13 is integrally formed with the base sheet 14. Yes. That is, the lower key top 13 b is fixed to the base sheet 14 via a molded fixing portion that becomes a boundary portion with the base sheet 14. The molding in this case can be performed by two-color molding, for example, using the lower key top 13b as a hard resin and the base sheet 14 as a thermoplastic elastomer. Further, for example, the lower key top 13b is made of a hard resin, the base sheet 14 is made of a thermosetting elastomer such as silicone rubber, and the lower key top 13b is placed on a molding die of the base sheet 14 and molded integrally. It is. According to this, since it is not necessary to place the lower key top 13b on the upper surface of the base sheet 14, a further reduction in thickness can be achieved.

Seventh Embodiment [FIG. 10] : In the seventh embodiment, the upper key top 4a and the lower key top 4b as in the first embodiment are replaced with separate key tops 4 without cutting the material. It is configured as a key top 15 that is an integral molded body that cannot be separated. When the key top 15 is formed as an integral molded body, the stopper 6 is formed by insert molding. In this embodiment as well, it is possible to achieve the same operations and effects as in the first embodiment, and in this embodiment, since the key top 15 is an integral molded body, an adhesion process or the like is unnecessary. There is an advantage that productivity can be improved.

Eighth Embodiment [FIG. 11] : In the eighth embodiment, the key top 16 is configured as an integral molded body as in the seventh embodiment, while having the same basic configuration as the first embodiment, and the key top 16 The elastic locking piece 16a is formed on the lower side of the plate. Therefore, in this embodiment, the key top 16 is press-fit into the through hole 6b of the spacer 6 and attached. Also in the present embodiment, similar to the seventh embodiment, it is possible to achieve the operations and effects that can improve the productivity, and it is also possible to exhibit the operations and effects in the first embodiment.

Modifications of each embodiment [FIGS. 12 to 15] : When each of the above embodiments is an illuminated key sheet, a translucent material is used for each member, and the stopper is made of a transparent hard resin. A light guide function can be added. Further, the shape of each member such as the key top is not limited to the shape exemplified in the above-described embodiment. Further, in each of the embodiments described above, an example of a narrow key sheet is shown, but each key top may be configured as a key sheet that is separated by a partition bar of a casing of the mobile phone.

  Moreover, in each said embodiment provided with the lower key top 4b, although the thing which the lower key top 4b became independent one by one was illustrated, the lower key top 4b is connected with the connection part 4f like FIG. 12, for example. Can be formed as In this way, by configuring all the lower key tops 4b as an integral resin molded body connected by the connecting portion 4f, the handleability at the time of manufacturing the key sheet 3 is good, and the productivity can be improved. When the lower key top 4b is configured as an integral resin molded body connected by the connecting portion 4f, the stopper 6 has a housing groove that is substantially relative to the resin molded body, for example, as shown in FIG. 6a can be configured.

  Moreover, it can replace with FIG. 12 and can comprise as a molded object of the lower keytop 4b and the connection part 4f like FIG. 14, for example. In FIG. 12, among the lower key tops 4b arranged in the fourth row and the third column, the lower key top 4b belonging to the fourth row is continuous with the connecting portion 4f at one place, and the lower key top 4b belonging to the first row to the third row. The key top 4b is continuous with the connecting portion 4f at two locations. For this reason, between the lower key top 4b belonging to the fourth row and the lower key top 4b belonging to the first row to the third row, the former has a lighter load during the pressing operation, and the latter has a heavier. In this way, the pressing operation load varies. However, with the configuration of FIG. 14, all the lower key tops 4b are continuous with the connecting portion 4f at one location, and therefore, the advantage that the load of the pressing operation can be made constant for all the lower key tops 4b. There is. In the case of the configuration shown in FIG. 14, the stopper 6 can be configured as shown in FIG.

The external appearance perspective view of a mobile telephone provided with the key sheet of 1st Embodiment. The expanded sectional view equivalent to the SA-SA line of FIG. FIG. 3 is a reduced plan view of the stopper shown in FIG. 2. Sectional drawing equivalent to FIG. 2 which shows the key sheet of 2nd Embodiment. FIG. 2A is a sectional view corresponding to FIG. 2 showing a key sheet of a third embodiment, and FIG. FIG. 5A is a sectional view corresponding to FIG. 2 showing a key sheet of a fourth embodiment, and FIG. 5B is a sectional view showing a modification of the sectional view (A). Sectional drawing equivalent to FIG. 2 which shows the key sheet of 5th Embodiment. Explanatory drawing which shows the manufacturing process of the key sheet | seat of FIG. Sectional drawing equivalent to FIG. 2 which shows the key sheet of 6th Embodiment. Sectional drawing equivalent to FIG. 2 which shows the key sheet of 7th Embodiment. Sectional drawing equivalent to FIG. 2 which shows the key sheet of 8th Embodiment. FIG. 2A is a plan view of a resin molded body in which the lower key top shown in FIG. 2 is connected by a connecting portion, and FIG. 2B is a sectional view taken along the line SC-SC in FIG. FIG. 13A is a plan view showing an embodiment of a stopper corresponding to the resin molded body in FIG. 12, and FIG. 13B is a sectional view taken along the line SD-SD in FIG. FIG. 13A is a plan view showing another embodiment of the resin molded body of FIG. 12, and FIG. 13B is a cross-sectional view taken along the line SE-SE of FIG. FIG. 15A is a plan view showing an embodiment of a stopper corresponding to the resin molded body of FIG. 14, and FIG. 15B is a sectional view taken along the line SF-SF of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cellular phone 2 Case 2a Operation opening 3 Key sheet 4 Key top 4a Upper key top 4b Lower key top 4c Protrusion 4d Locking flange 4e Locking groove 4f Connection part 5 Base sheet 5a Non-operation part 5b Flexible operation part 5c Pusher 5d Holding portion 5e Holding portion 5f Mounting protrusion 6 Stopper (detachment regulating member)
6a accommodation groove 6b through hole 6c locking hole 7 adhesive layer 8 decorative printing layer 9 adhesive layer 10 stopper (detachment regulating member)
11 Key Top 11a Upper Key Top 11b Lower Key Top 11c Recess 11d Protrusion 12 Base Sheet 12a Through Hole 13 Key Top 13a Upper Key Top 13b Lower Key Top 14 Base Sheet 15 Key Top 16 Key Top 16a Elastic Locking Piece

Claims (12)

A base sheet made of a rubber-like elastic body;
A key top with a locking groove on the side;
The key top has a through hole through which the key top passes, the hole edge of the through hole enters the locking groove of the key top, and the locking groove in the direction in which the key top is separated from the base sheet. A key sheet for a pushbutton switch, comprising: a detachment regulating member to be locked.   3. The key sheet for a pushbutton switch according to claim 2, wherein the key top is constituted by mutually fixing an upper key top and a lower key top which are separated from each other with a locking groove as a boundary.   3. A key sheet for a pushbutton switch according to claim 2, wherein the upper key top is formed of a transparent resin and has a flat bottom surface, and a decorative print layer for decorating the upper key top on the bottom surface.   3. The key sheet for a pushbutton switch according to claim 2, wherein either one of the upper key top and the lower key top has an insertion recess, and the other has an insertion protrusion.   The key sheet for a pushbutton switch according to any one of claims 1 to 4, wherein the key top is fixed to the base sheet via a molded fixing portion.   The key sheet for a pushbutton switch according to any one of claims 1 to 5, wherein the base sheet has a holding portion that wraps around the surface of the detachment regulating member and holds the detachment regulating member on the front and back sides.   The through hole of the detachment regulating member is formed as a gap between the key top locking groove and the key top so as not to cause a lateral displacement of the key top with respect to the pressing operation shaft of the key top. A key sheet for a pushbutton switch according to any one of claims 1 to 6.   The key sheet for a pushbutton switch according to any one of claims 1 to 7, wherein the detachment regulating member is fixed to the base sheet via an adhesive layer.   The key sheet for a pushbutton switch according to any one of claims 1 to 8, wherein a hole edge of the through hole on the back surface of the detachment regulating member abuts against the locking groove in the key top pressing operation direction.   The key sheet for a pushbutton switch according to any one of claims 1 to 9, wherein the detachment regulating member is formed of any one of a hard resin plate, a resin film, and a metal plate.   The key sheet for a pushbutton switch according to any one of claims 1 to 10, comprising a plurality of the key tops and a connecting portion extending between the key tops as an integral molded body.   The key sheet for a pushbutton switch according to any one of claims 1 to 11, wherein a plurality of the key tops are arranged narrowly on a base sheet so as to be exposed from an operation opening without a partition rail formed in a housing of the device.

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