JP2012234721A - Printed wiring board, key module including the printed wiring board, and electronic apparatus including the key module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board which maintains good connection reliability by effectively preventing peeling of a movable contact sheet in a printed wiring board including a movable contact sheet covering a dome shaped movable contact, and to provide a key module including the printed wiring board and an electronic apparatus including the key module.SOLUTION: A printed wiring board 10 includes: a fixed contact 12a; a dome shaped movable contact 13; and a movable contact sheet 14 covering the movable contact 13 on a base material 11a. The movable contact sheet 14 is folded at an end part of the base material 11a from the surface 11a-1 side of the base material to the rear surface 11a-3 side and is bonded to the surface side and the rear surface side of the base material 11a.

Description

  The present invention relates to a printed wiring board including a movable contact sheet that covers a dome-shaped movable contact, a printed wiring board that can effectively prevent the movable contact sheet from being peeled off, a key module including the printed wiring board, and The present invention relates to an electronic device including the key module.

In electronic devices such as mobile phones, notebook computers, digital cameras, and the like, in general, a desired input operation can be performed using a key module having an input key for inputting a predetermined command.
In addition, as a part of the configuration of the key module, a printed wiring board having a dome-shaped movable contact that is switched on and switched off by being brought into contact with or not in contact with a fixed contact formed on the conductive pattern is used. .
Such dome-shaped movable contacts are generally covered with an elastic sheet and disposed on a substrate.
As a prior art showing such a key module, for example, there is Patent Document 1 below.

JP 2008-181791 A

The above-mentioned patent document 1 is an invention relating to a movable contact unit for a switch and a switch device using the same, and is a switch with good illumination quality that can reduce assembly costs, reduce manufacturing costs and power consumption, and suppress light guide loss. A movable contact unit for a switch and a switch device using the movable contact unit for a switch are disclosed.
However, a conventional key module as shown in Patent Document 1 generally has a configuration in which an elastic sheet that covers a dome-shaped movable contact is attached only to the surface side of a substrate.
In such a configuration, when the distance from the outer periphery of the dome-shaped movable contact to the end of the substrate is short, the movable contact sheet is peeled off particularly when the input key is pressed, and the dome-shaped movable contact and the substrate are formed. As a result of foreign matter entering the space, a connection failure between the movable contact and the fixed contact occurs, and there is a problem that good connection reliability cannot be maintained.

  Therefore, the present invention solves the above-described conventional problems, and in the printed wiring board including the movable contact sheet that covers the dome-shaped movable contact, it is possible to effectively prevent the movable contact sheet from being peeled off. It is an object of the present invention to provide a printed wiring board capable of maintaining connection reliability, a key module including the printed wiring board, and an electronic device including the key module.

  The printed wiring board of the present invention is a printed wiring board comprising a fixed contact, a dome-shaped movable contact, and a movable contact sheet covering the movable contact on a substrate, and the movable contact sheet includes the base The first feature is that the end portion of the material is folded from the front surface side to the back surface side of the base material and adhered to the front surface side and the back surface side of the base material.

  According to the first feature of the present invention, the printed wiring is a printed wiring board comprising a fixed contact, a dome-shaped movable contact, and a movable contact sheet that covers the movable contact on a substrate, Since the movable contact sheet is folded from the front surface side to the back surface side of the base material at the end portion of the base material and adhered to the front surface side and the back surface side of the base material, A sufficient contact area of the movable contact sheet can be secured, and the adhesive force of the movable contact sheet can be favorably maintained. Therefore, it is possible to effectively prevent the movable contact sheet from peeling off and maintain good connection reliability.

  Further, in the printed wiring of the present invention, in addition to the first feature of the present invention, the movable contact sheet is folded from the front surface side to the back surface side of the base material at the opposite end of the base material. Is the second feature.

  According to the second feature of the present invention, in addition to the function and effect of the first feature of the present invention, the movable contact sheet has a back surface from the front surface side of the base material at an opposite end of the base material. Since it is folded back to the side, the adhesive area of the movable contact sheet can be sufficiently secured at the end portion of the base material, and the adhesive force of the movable contact sheet can be more satisfactorily maintained. Therefore, it is possible to effectively prevent the movable contact sheet from being peeled off, and it is possible to maintain better connection reliability.

  In addition to the first or second feature of the present invention, the printed wiring board of the present invention has a third feature that the printed wiring board is a flexible printed wiring board.

  According to the third feature of the present invention, in addition to the function and effect of the first or second feature of the present invention, the printed wiring board is a flexible printed wiring board. The printed wiring board can be easily folded from the back side to the back side, the work efficiency is good, and the thickness can be reduced.

  The key module of the present invention includes a printed wiring board according to any one of the first to third features, an input key for inputting a predetermined command, and between the printed wiring board and the input key. A fourth feature is that the light guide plate includes a light guide plate that guides incident light through the thickness and emits the light to the outside at a predetermined position, and a light source that causes the light to enter the light guide plate.

  According to the fourth aspect of the present invention, the key module includes the printed wiring board according to any one of the first to third characteristics, an input key for inputting a predetermined command, and the printed wiring. The dome includes a light guide plate that is disposed between the plate and the input key and guides the incident light to the outside at a predetermined position while guiding the light within the thickness, and a light source that causes the light to enter the light guide plate. Good connection reliability can be maintained by having a printed wiring board that can effectively prevent the movable contact sheet covering the movable contacts from being peeled off. In addition, it is possible to obtain a key module that has high work efficiency and can be thinned.

  According to a fifth aspect of the present invention, there is provided an electronic apparatus including the key module according to the fourth aspect.

  According to the fifth aspect of the present invention, since the electronic device includes the key module according to the fourth aspect, it effectively prevents the movable contact sheet covering the dome-shaped movable contact from being peeled off. By providing a key module having a printed wiring board that can be used, good connection reliability can be maintained. In addition, the working efficiency can be improved, and the electronic device can be thinned.

According to the printed wiring board of the present invention, it is possible to effectively prevent the movable contact sheet covering the dome-shaped movable contact from being peeled off, so that good connection reliability can be maintained.
In addition, according to the key module of the present invention, it is possible to maintain good connection reliability by having a printed wiring board that can effectively prevent the movable contact sheet covering the dome-shaped movable contact from being peeled off. Can do. In addition, it is possible to obtain a key module that has high work efficiency and can be thinned.
In addition, according to the electronic device of the present invention, it is possible to provide a key module having a printed wiring board that can effectively prevent the movable contact sheet covering the dome-shaped movable contact from being peeled off. Can be maintained. In addition, the working efficiency can be improved, and the electronic device can be thinned.

1 is a perspective view showing a mobile phone according to an embodiment of the present invention. It is a figure which shows the key module which concerns on embodiment of this invention, (a) is a top view which shows the whole key module, (b) is a top view which shows the principal part of (a). It is a top view which shows the movable contact sheet which comprises the printed wiring board which concerns on embodiment of this invention, and shows the state before folding a movable contact sheet to the back surface side of a base material. It is sectional drawing in the AA direction of FIG.2 (b). It is sectional drawing of the principal part which shows the modification of the key module which concerns on embodiment of this invention. It is sectional drawing of the principal part which shows the conventional key module.

  With reference to the following drawings, a printed wiring board according to an embodiment of the present invention, a key module including the printed wiring board, and an electronic apparatus including the key module will be described for understanding of the present invention. However, the following description does not limit the invention described in the claims of the present invention.

First, a printed wiring board 10 according to an embodiment of the present invention, a key module 2 including the printed wiring board 10, and a mobile phone 1 as an electronic apparatus including the key module 2 will be described with reference to FIGS. .
As shown in FIG. 1, the mobile phone 1 includes an input unit 1a and a display unit 1b. The display unit 1b is openable and closable with respect to the input unit 1a via a hinge unit 1c.

Referring also to FIG. 2, the input unit 1 a includes a key module 2 as an input module in a case 1 d that forms the outer shape of the mobile phone 1.
As shown in FIGS. 2 and 4, the key module 2 includes a printed wiring board 10, an input operation unit 20, a light guide plate 30, and a light source 40.

The printed wiring board 10 is a circuit board provided with a fixed contact and a movable contact for performing an input operation, a wiring circuit, and the like.
As shown in FIG. 4, the printed wiring board 10 mainly includes an insulating resin layer 11, a conductive layer 12, a movable contact 13, a movable contact sheet 14, and an adhesive 15.
In addition, in this embodiment, while using a flexible printed wiring board as the printed wiring board 10, it is set as the structure which uses what is called a single-sided printed wiring board provided with the conductive layer 12 on the single side | surface of a base material.

The insulating resin layer 11 is a layer that forms a base material 11a and an insulating layer (a so-called coverlay layer (not shown)) of the printed wiring board 10, and is formed of an insulating resin film.
As a resin film, what consists of a resin material excellent in the softness | flexibility is used. For example, any film may be used as long as it is normally used as a resin film for forming an insulating resin layer of a printed wiring board, such as a polyimide film or a polyester film.
In particular, those having high heat resistance in addition to flexibility are desirable. For example, polyamide resin films, polyimide resin films such as polyimide and polyamideimide, and polyethylene naphthalate can be preferably used.
As the heat resistant resin, any resin such as polyimide resin or epoxy resin may be used as long as it is normally used as the heat resistant resin for forming the insulating resin layer of the printed wiring board.
The thickness of the insulating resin layer 11 is desirably about 5 μm to 50 μm for the substrate 11 a and about 5 μm to 80 μm for the insulating layer.

The conductive layer 12 is a layer made of a conductive metal in the printed wiring board 10 that forms a fixed contact 12a as a conductive pattern, a wiring circuit, or the like.
The conductive layer 12 is formed by laminating a conductive metal foil on the base material 11a using plating (so-called additive method), or etching a conductive metal foil previously laminated on the base material 11a (so-called subtractive method). It can form using well-known formation methods, such as.
Moreover, copper (Cu) can be used as the conductive metal foil. Of course, it is not limited to copper (Cu), and any material can be used as long as it is normally used as a conductive metal foil for forming a conductive layer of a printed wiring board.
The thickness of the conductive layer 12 is preferably about 5 μm to 50 μm.

The movable contact 13 is a dome-shaped conductive metal film constituting a so-called dome switch that is turned on and off by being brought into contact with or not in contact with the fixed contact 12a.
More specifically, the key module 2 is turned on / off by being covered with the movable contact sheet 14 and being brought into contact with or not in contact with the fixed contact 12a following the operation of an input key 21 described later.
Note that copper or the like can be used as the conductive metal film.

The movable contact sheet 14 is an elastic sheet that mainly covers the movable contact 13 and transmits the pressing force from the input key 21 to the movable contact 13.
As shown in FIG. 4, the movable contact sheet 14 is bonded onto the insulating resin layer 11 via an adhesive 15.
Further, in the present embodiment, as shown in FIGS. 3 and 4, the end of the base material 11a is folded back from the front surface side to the back surface side of the base material 11a, and adhered to the front surface side and the back surface side of the base material 11a. It is.
More specifically, the folded region of the movable contact sheet 14 in the entire region to be bonded to the end portion of the base material 11a (more specifically, the end portion in the longitudinal direction of the base material 11a as shown in FIG. 3). K is provided, and the folded region K is folded back from the front surface side to the back surface side along the end surface 11a-2 at the end of the base material 11a, and the front surface 11a-1, end surface 11a-2, and back surface 11a of the base material 11a. -3 and the adhesive 15 are bonded together.
Here, as shown in FIGS. 3 and 4, the “folding region” means that the movable contact sheet 14 is bonded to the end surface 11 a-2 and the back surface 11 a-3 side of the base material 11 a via the adhesive 15. It means the area to be done.
In addition, as for the size of the folding region K, it is desirable that the width L of the movable contact sheet 14 bonded to the back surface 11a-3 side shown in FIG.
The thickness of the movable contact sheet 14 is preferably about 20 μm to 50 μm.
As the elastic sheet, a soft elastic sheet such as rubber can be used.
For example, the movable contact sheet 14 is bonded to the front surface 11a-1 side with an adhesive 15 in a state where the movable contact sheet 14 is aligned with the insulating resin layer 11, and then the folded region K is formed on the end surface 11a-2 and the back surface. It can be adhered to the insulating resin layer 11 by being folded along the line 11a-3 and bonded to the end face 11a-2 and the back face 11a-3 via the adhesive 15.

The adhesive 15 is for bonding the movable contact sheet 14 to the insulating resin layer 11.
As the adhesive 15, any adhesive such as an epoxy resin may be used as long as it is normally used as an adhesive for attaching the movable contact sheet constituting the key module to the insulating resin layer.

  The input operation unit 20 is for an operator to perform a predetermined input operation. As shown in FIGS. 2 and 4, an input key 21 exposed from the case 1d and a key arranged inside the case 1d. And a sheet 22.

The input key 21 is a member that is pressed when an operator performs a predetermined input operation.
The input key 21 is made of a transparent hard resin, and is provided with a specific shape such as a numeral, an alphabet, and a symbol so as to be visible. In addition, the formation method of specific shapes, such as a number, an alphabet, a symbol, may be any of marking a specific shape with a light-shielding material and marking a non-specific shape with a light-shielding material.

The key sheet 22 is a sheet-like member for mainly transmitting the pressing force of the input key 21 to the movable contact 13.
The key sheet 22 is formed of a transparent resin such as polyester, polycarbonate, or polyurethane. As shown in FIG. 4, the key sheet 22 is provided with a pusher 22 a at a position corresponding to the input key 21.

The light guide plate 30 is positioned below the input key 21 and illuminates the input key 21 with light incident from the light source 40. More specifically, the light emitted from the light source 40 is made incident from the light incident end face 31 shown in FIG. 2B and guided while being totally reflected in the thickness, and at the position corresponding to the input key 21, the outside of the plate. And the input key 21 is illuminated.
As shown in FIG. 4, a light emitting structure 32 that emits light that has passed through the light guide plate 30 toward the input key 21 is provided on the lower surface side at a position corresponding to the presser 22 a in the light guide plate 30. Yes.
As shown in FIG. 4, the light emitting structure portion 32 is configured by an uneven pattern. The uneven shape can be formed by hot stamping, injection molding, microblasting, or other methods.
The light guide plate 30 is made of a resin that can sufficiently transmit light in the visible light region, such as polycarbonate, acrylic, polyurethane, norbornene resin.
Further, it is desirable that the light guide plate 30 has a thickness of 50 μm to 400 μm, and the light emitting structure 32 has a thickness of 0.5 μm to 50 μm.
The number of the light emitting structures 32 is not limited to that of the present embodiment, and can be changed as appropriate.

  The light source 40 causes light to enter the light guide plate 30 and can be formed of, for example, an LED. Further, as shown in FIG. 2B, the light source 40 is installed on the printed wiring board 10 at a position facing the light incident end face 31 of the light guide plate 30.

  The key module 2 configured as described above is switched on and off when the movable contact 13 and the fixed contact 12a are brought into contact or non-contact with the operation of the input key 21 through the pusher 22a. Is called.

The printed wiring board 10 having such a configuration, the key module 2 including the printed wiring board 10, and the mobile phone 1 including the key module 2 have the following effects.
By providing the light emitting structure 32 on the light guide plate 30, the light that has passed through the light guide plate 30 can be efficiently emitted toward the input key 21. Therefore, the luminance of the input key 21 can be improved efficiently. Therefore, the key module 2 and the mobile phone 1 that can realize good luminance can be obtained.
In addition, by configuring the light emitting structure 32 with a concavo-convex pattern, the light that has been guided through the light guide plate 30 in a total reflection state is reliably scattered at the position of the physical concavo-convex pattern, and the input key 21. The light can be emitted in the direction. Therefore, the luminance of the input key 21 can be improved more efficiently. Therefore, the key module 2 and the mobile phone 1 that can realize much better luminance can be obtained.
Further, a folding region K is provided in the movable contact sheet 14 at an end portion in the longitudinal direction of the base material 11a, and the folding region K extends along the end surface 11a-2 at the end portion of the base material 11a from the front surface side to the back surface side. First, the end of the base material 11a is formed by being folded and integrally bonded to the front surface 11a-1, the end surface 11a-2, the back surface 11a-3 and the adhesive 15 of the base material 11a. The movable contact sheet 14 can be bonded not only on the front surface 11a-1 but also on the end surface 11a-2 and the back surface 11a-3. Therefore, especially when the length of the width M shown in FIGS. 3 and 4 is short (specifically, when it is 1 mm or less), the movable contact sheet 14 and the insulating resin layer 11 are formed at the end of the base material 11a. The adhesion area of the movable contact sheet 14 to the insulating resin layer 11 can be satisfactorily maintained.
Secondly, in the movable contact sheet 14, the folded region K is provided in the region that is bonded to the longitudinal end portion of the base material 11 a, so that the movable contact sheet 14 is bonded to the end portion of the base material 11 a in the short direction. Compared with the configuration in which the folded region K is provided, the adhesion area between the movable contact sheet 14 and the insulating resin layer 11 can be effectively increased at the end of the base material 11a. Therefore, the adhesive force of the movable contact sheet 14 to the insulating resin layer 11 can be more satisfactorily maintained at the end of the base material 11a.
Third, as shown in FIG. 4, at the end of the base material 11 a, the movable contact sheet 14 wraps around from the front surface side to the back surface side of the base material 11 a, and the insulating resin layer 11 is sandwiched between the movable contact sheet 14. be able to.
Accordingly, even when the length of the width M is short, when the input key 21 is pushed, the movable contact sheet 14 is lifted at the end of the base material 11a by the pressing force applied to the movable contact sheet 14, and the insulating resin layer 11 can be effectively prevented from being peeled off. Therefore, particularly when the mobile phone 1 is used, the movable contact sheet 14 is effectively peeled off from the insulating resin layer 11 so that foreign matter enters the space formed by the movable contact 13 and the insulating resin layer 11. Can be prevented. Therefore, it is possible to effectively prevent a contact failure between the movable contact 13 and the fixed contact 12a due to the intrusion of the foreign matter.
Therefore, the printed wiring board 10, the key module 2, and the mobile phone 1 that can maintain good electrical and mechanical connection reliability can be obtained.
In this case and the following description, “the length of the width M” means “the length from the outer periphery of the movable contact 13 to the end of the base material 11 a”.
Further, by using a flexible printed wiring board as the printed wiring board 10, the printed wiring board can be easily folded from the front surface side to the back surface side of the substrate 11 a, and the work efficiency is good and the thickness can be reduced. 10, the key module 2, and the mobile phone 1.

On the other hand, as shown in FIG. 6, the conventional key module 3 has a configuration in which the movable contact sheet 140 is adhered only to the surface 110a-1 side of the substrate 110a.
In such a configuration, when the width M is short at the end of the base 110a, the bonding area between the movable contact sheet 140 and the insulating resin layer 110 is reduced, and the movable contact with respect to the insulating resin layer 110 is reduced. The adhesive force of the sheet 140 cannot be maintained well.
Therefore, when the input key 210 is pushed, the movable contact sheet 140 is lifted and peeled off at the end of the base 110a by the pressing force applied to the movable contact sheet 140, so that the movable contact 130 and the insulating resin layer 110 are separated. There is a problem in that foreign matter enters the space formed by, and a contact failure between the movable contact 130 and the fixed contact 120a occurs.
Such a problem has become more prominent due to the downsizing of the printed wiring board constituting the key module as electronic devices have been downsized in recent years.
In the conventional key module 3, the same member and the same function as those of the key module 2 described above are given the same one-digit or first two-digit number and alphabet, and detailed description is omitted. It shall be.

  Therefore, with the configuration of the key module 2 according to the embodiment of the present invention, the key module 2 and the electronic device 1 having high electrical and mechanical connection reliability can be obtained.

Next, a modification of the key module 2 according to the embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 5, the key module 4 according to this modification is obtained by changing the configuration of the folded region K with respect to the key module 2 described above. Other configurations are the same as those of the key module 2 according to the embodiment of the present invention described above. Accordingly, the same members and the same functions as those of the key module 2 are denoted by the same reference numerals, and the following description is omitted.
More specifically, in the movable contact sheet 14, a folded region K is provided in the entire region to be bonded to the end portion facing the longitudinal direction of the base material 11 a, and the movable contact sheet 14 is attached to the end portion facing the base material 11 a. The base material 11a is folded back from the front surface side to the back surface side, and is integrally bonded to the front surface 11a-1, the end surface 11a-2, the back surface 11a-3 and the adhesive 15.
By setting it as such a structure, 1stly, the adhesion area of the movable contact sheet 14 and the insulating resin layer 11 can be ensured more fully in the edge part of the base material 11a, and the insulating resin layer 11 is sufficient. It is possible to hold the adhesive force of the movable contact sheet 14 to the better.
Secondly, in the movable contact sheet 14, a folded region K is provided in a region where the movable contact sheet 14 is bonded to the opposite end in the longitudinal direction of the base material 11 a, so that the opposite end in the short direction of the base material 11 a Compared to the configuration in which the folded region K is provided in the region to be bonded, the bonding area between the movable contact sheet 14 and the insulating resin layer 11 can be further effectively increased at the end of the base material 11a. Therefore, the adhesive force of the movable contact sheet 14 to the insulating resin layer 11 can be more satisfactorily maintained at the end of the base material 11a.
Third, as shown in FIG. 5, the movable contact sheet 14 wraps around from the front surface side to the back surface side of the base material 11 a at the opposite end of the base material 11 a, and the insulating resin layer 11 is moved to the movable contact sheet 14. Can be pinched.
Accordingly, even when the length of the width M is short, when the input key 21 is pushed, the movable contact sheet 14 is lifted at the end of the base material 11a by the pressing force applied to the movable contact sheet 14, and the insulating resin layer 11 can be more effectively prevented from being peeled off.
Therefore, particularly when the mobile phone 1 is used, the movable contact sheet 14 is peeled off from the insulating resin layer 11, so that foreign matter enters the space formed by the movable contact 13 and the insulating resin layer 11. Can be prevented. Therefore, it is possible to more effectively prevent the contact failure between the movable contact 13 and the fixed contact 12a due to the intrusion of the foreign matter.
Therefore, the key module 4 can maintain the electrical and mechanical connection reliability more satisfactorily.
In this modification, the width L of the movable contact sheet 14 bonded to the back surface 11a-3 shown in FIG. 5 is the same length in the folded region K bonded to the opposite end of the substrate 11a. .

In the present embodiment and the modified example, the folded region K of the movable contact sheet 14 is provided in the entire region to be bonded to the end in the longitudinal direction of the base material 11a. However, the configuration is not necessarily limited to such a configuration. is not. For example, it is good also as a structure which provides the folding | turning area | region K in a part of area | region made to adhere | attach with the edge part of the longitudinal direction of the base material 11a, or several places. Moreover, it is good also as a structure which provides the folding | returning area | region K in all or one part of the area | region bonded with the edge part of the transversal direction of the base material 11a. Moreover, it is good also as a structure which provides the folding | turning area | region K in both the longitudinal direction of the base material 11a, and a transversal direction.
However, it is preferable that the folding region K is provided at least in the region near the movable contact 13. Here, the “region in the vicinity of the movable contact 13” means “a region surrounded by four sides of about 5 mm from the center of the movable contact 13”.
In the present embodiment, as shown in FIG. 3, the folded region K is formed in a rectangle having a vertical length of N and a horizontal length of P. However, the present invention is not limited to this configuration. For example, it may be configured to have an arbitrary shape such as a semicircular shape.
In the present embodiment and the modification, the configuration of the printed wiring board 10 is a so-called single-sided printed wiring board including the conductive layer 12 on one side of the base material 11a. However, the configuration is not necessarily limited to such a configuration. Alternatively, a so-called double-sided printed wiring board having the conductive layers 12 on both sides of the substrate 11a may be used.
Further, in the present embodiment, the light emitting structure portion 32 is formed by a concavo-convex pattern, but the present invention is not necessarily limited to such a configuration. For example, it can be formed by printing with an ink containing a light scattering agent. With this configuration, the light guided in the total reflection state in the light guide plate 30 can be reliably scattered at the position of the print pattern including the light scattering agent and emitted toward the input key 21. Therefore, the luminance of the input key 21 can be improved. Moreover, by using a printing pattern, the light guide plate 30 can be made thin, and the key module 2 and the mobile phone 1 can be downsized.
Of course, it is good also as a structure which does not provide the light-projection structure part 32 in the light-guide plate 30. FIG.
Moreover, the magnitude | size, shape, number, arrangement position, etc. of the printed wiring board 10, the input operation part 20, the light guide plate 30, and the light source 40 are not restricted to the thing of this embodiment, It can change suitably.
In this modification, the width L of the movable contact sheet 14 bonded to the back surface 11a-3 is set to be the same length in the folded region K bonded to the opposite end of the substrate 11a. The configuration is not necessarily limited to such a configuration, and the width L of the movable contact sheet 14 bonded to the back surface 11a-3 is set to have different lengths in the folded region K bonded to the opposite end of the substrate 11a. It is good.

  The present invention can be used as an electronic device such as a cellular phone and a key module used therefor.

DESCRIPTION OF SYMBOLS 1 Mobile telephone 1a Input part 1b Display part 1c Hinge part 1d Case 2 Key module 3 Key module 4 Key module 10 Printed wiring board 11 Insulating resin layer 11a Base material 11a-1 Front surface 11a-2 End surface 11a-3 Back surface 12 Conductive layer 12a Fixed contact 13 Movable contact 14 Movable contact sheet 15 Adhesive 20 Input operation part 21 Input key 22 Key sheet 22a Pusher 30 Light guide plate 31 Light incident end face 32 Light emitting structure part 40 Light source 3d Case 100 Printed wiring board 110 Insulating resin Layer 110a Base 110a-1 Surface 120 Conductive layer 120a Fixed contact 130 Movable contact 140 Movable contact sheet 150 Adhesive 200 Input operation unit 210 Input key 220 Key sheet 220a Pusher 300 Light guide plate 320 Light emitting structure 400 Light source K Fold Area L width M width N length P length returns

Claims (5)

  A printed wiring board comprising a fixed contact, a dome-shaped movable contact, and a movable contact sheet covering the movable contact on a substrate, wherein the movable contact sheet is formed at an end of the substrate. A printed wiring board, wherein the printed wiring board is folded from the front surface side to the back surface side and adhered to the front surface side and the back surface side of the substrate.   2. The printed wiring board according to claim 1, wherein the movable contact sheet is folded from the front surface side to the back surface side of the base material at opposite ends of the base material.   The printed wiring board according to claim 1, wherein the printed wiring board is a flexible printed wiring board.   The printed wiring board according to any one of claims 1 to 3, an input key for inputting a predetermined command, and a thickness of incident light disposed between the printed wiring board and the input key. A key module comprising: a light guide plate that emits light to the outside at a predetermined position while guiding light inside; and a light source that causes light to enter the light guide plate.   An electronic apparatus comprising the key module according to claim 4.

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