Patent Application
20210166896
The present application relates to a switch unit having noiselessness and a method for producing a switch substrate.
Conventionally, a push-type switch device includes: a switch substrate; a contact member formed on the switch substrate; and a pressing member made up of elements such as a conductive flat spring that is brought into contact with the contact member to make a conduction. In this push-type switch device, a switching operation is performed by elastically deforming the pressing member toward the contact member.
The switch unit 201 is mounted on a mount substrate 23, such as a mother board. Generally, the switch substrate 202 is made of a hard material such as a glass epoxy substrate (FR-4). The first contact point 13 is provided at a center portion on the switch substrate 202. The second contact point 14 is provided around the first contact point 13. The conduction spring member 15 is provided over the first contact point 13 and the second contact point 14, which are contact members, and is elastically deformable to contact the first contact point 13, thereby making a conduction between the first contact point 13 and the second contact point 14.
While the pressing member is being pressed, there is a conduction between the pressing member and the contact members. Upon release from the pressing state, the conduction between the pressing member and the contact members is broken. In this press manipulation, contact sound is generated at the time when the pressing member contacts the contact members. This contact sound serves as a way of confirming that a switching is performed reliably. If, however, the contact sound generated is higher than necessary, the contact sound is equivalent to impact sound.
In order to reduce such contact sound generated at the time of a switching operation, some switch devices have been proposed that incorporate a material such as a shock-absorbing material and a sound-absorbing material between the switch substrate and the pressing member. Patent document 1 discloses a switch device that includes a cover member, a click sheet, a buffer conductive sheet, and a switch substrate having a fixed contact formed on a surface of the switch substrate. In this cover member, a base and a key top are connected to each other at a skirt. The key top has a plunger that is formed on the lower surface of the key top and that protrudes downward. Patent document 2 and patent document 3 disclose switch devices each including: a switch substrate having a pair of contact members provided on a surface of the switch substrate; a pressing member made of a dome-shaped metal plate having a property of a deformable spring; and a shock-absorbing material provided between the switch substrate and the pressing member.
Patent document 4 discloses a touch panel device that includes: a touch panel substrate; a transmitter that transmits an elastic surface wave to the touch panel substrate; a receiver that receives the elastic surface wave that has been transmitted through the touch panel substrate; and a sheet material serving as a pressing member. The sheet material has an input surface and is provided at a distance from the touch panel substrate such that the surface opposite to the input surface faces the touch panel substrate. The sheet material is flexible and includes: a soft layer made of a soft material; and a pair of hard layers made of a hard material harder than the soft material. By pressing the input surface, the pressed portion is partially bent into contact with the touch panel substrate.
Patent document 1: JP 2001-43772A
Patent document 2: JP 2012-243609A
Patent document 3: JP 2017-79133A
Patent document 4: JP 2009-3672A
In the switch device recited in patent document 1, the buffer conductive sheet is provided on the switch substrate. In this switch device, the buffer conductive sheet is provided with a predetermined degree of hardness to improve click sensitivity. This switch device, however, has no structure that decreases contact sound generated by clicking. In the switch devices recited in patent document 2 and patent document 3, a shock-absorbing material is provided between the switch substrate and the pressing member in order to decrease contact sound generated at the time when the pressing member is pressed into contact with the switch substrate. This shock-absorbing material, however, is made up of an upper sheet and a lower sheet attached to each other via a spacer sheet having a removal hole at a position corresponding to a fixed contact portion. This leaves a gap between the upper sheet and the lower sheet, and the gap may undermine the click sensitivity of the shock-absorbing material.
In the touch panel device recited in patent document 4, the sheet material facing the touch panel substrate is made up of: a hard layer that maintains the shape of the sheet material; and a soft layer covering the hard layer. This configuration decreases the contact sound generated at the time when the sheet material is pressed toward the touch panel substrate. However, the soft layer may absorb the repulsive force generated when the sheet material is pressed toward the touch panel substrate, undermining the click sensitivity of the sheet material. Also, it is not easy to produce a sheet material made up of a soft layer and a hard layer while securing a predetermined distance from the touch panel substrate, and there may be stroke variations occurring when the sheet material is pressed toward the touch panel substrate.
In light of the considerations above, it is an object of the present application to provide a switch unit including a switch substrate that decreases contact sound generated at the time of switching without undermining switching operability.
A switch unit according to a first embodiment of the present application includes: a substrate including a hard layer and a soft layer; a first contact point provided on an upper surface of the substrate and above the soft layer; a second contact point provided on the upper surface of the substrate and around the first contact point; a conduction spring member provided in a non-contact state with the first contact point above the first contact point and in contact state with the second contact point, the conduction spring member being elastically deformable into contact with the first contact point to make a conduction between the first contact point and the second contact point; a first external electrode provided at an end portion of the substrate; a first through-hole electrode provided at an inside portion of the substrate and electrically connected to the first contact point; and a first wiring pattern provided on a lower surface of the substrate and electrically connected to the first external electrode and the first through-hole electrode.
A switch unit according to a second embodiment of the present application includes: a substrate including a hard layer and a soft layer; a first contact point provided on an upper surface of the substrate and above the soft layer; a second contact point provided on the upper surface of the substrate and around the first contact point; a conduction spring member provided in a non-contact state with the first contact point above the first contact point and in contact state with the second contact point, the conduction spring member being elastically deformable into contact with the first contact point to make a conduction between the first contact point and the second contact point; a first external electrode and a second external electrode provided at end portions of the substrate; a first connection electrode provided at an inside portion of the substrate and electrically connecting the first contact point and the first external electrode to each other; and a second connection electrode provided at an inside portion of the substrate and electrically connecting the second contact point and the second external electrode to each other.
A switch unit according to a third embodiment of the present application includes a substrate, a first contact point, a second contact point, and a conduction spring member. The substrate includes: a cavity formed in the substrate; an opening formed on an upper surface of the substrate; and a connection hole connecting the opening and the cavity to each other. The first contact point is provided on the upper surface of the substrate. The second contact point is provided around the first contact point. The conduction spring member is provided in a non-contact state with the first contact point above the first contact point and in contact state with the second contact point, the conduction spring member being elastically deformable into contact with the first contact point to make a conduction between the first contact point and the second contact point. A maximum value of a sectional area of the connection hole parallel to the upper surface of the substrate is smaller than a maximum value of a sectional area of the cavity parallel to the upper surface of the substrate.
A method for producing the switch substrate according to the first embodiment of the present application includes a forming step of obtaining an aggregate switch substrate by forming a soft layer on a lower surface of an aggregate switch substrate member. The aggregate switch substrate member includes: an aggregate substrate including a hard layer; a plurality of first contact points provided on an upper surface of the aggregate substrate; a plurality of second contact points provided on the upper surface of the aggregate substrate and around the respective first contact points; a plurality of first through-hole electrodes provided at an inside portion of the aggregate substrate and electrically connected to the respective first contact points; a plurality of second through-hole electrodes electrically connected to the respective second contact points; a plurality of through holes extending between the upper surface and a lower surface of the aggregate substrate, each through hole of the through holes including a conduction layer as a side surface of the each through hole; a plurality of first wiring patterns provided on a lower surface of the aggregate substrate, each first wiring pattern of the first wiring patterns being electrically connected to the conduction layer and each first through-hole electrode of the first through-hole electrodes; and a plurality of second wiring patterns each electrically connected to the conduction layer and each second through-hole electrode of the second through-hole electrodes. The soft layer covers at least portions immediately under the plurality of first contact points, and does not cover the plurality of through holes. The method also includes a cutting step of obtaining individual switch substrates by cutting the aggregate switch substrate through at least the plurality of through holes.
A method for producing the switch substrate according to the second embodiment of the present application includes a joining step of obtaining an aggregate switch substrate by joining a first aggregate substrate and a second aggregate substrate to each other. The first aggregate substrate includes: a plurality of first contact points formed on an upper surface of the first aggregate substrate; a plurality of second contact points provided around the respective first contact points and formed on the upper surface of the first aggregate substrate; and a plurality of through holes. The second aggregate substrate includes a plurality of cavities open on an upper surface of the second aggregate substrate. A maximum value of a sectional area of each of the cavities parallel to the upper surface of the first aggregate substrate is larger than a maximum value of a sectional area of each of the through holes parallel to the upper surface of the first aggregate substrate. The plurality of through holes overlap the plurality of respective cavities in a vertical direction. The method also includes a cutting step of obtaining individual switch substrates by cutting the aggregate switch substrate.
In the switch unit according to the first embodiment of the present application, the substrate includes a hard layer and a soft layer, and a first contact point is provided above the soft layer. This configuration ensures that the pressing force of pressing the conduction spring member is supported by the hard layer, and that the soft layer absorbs: the contact sound generated at the time when the conduction spring member contacts the first contact point; and the sound that is caused when a vibration involved in the collision of the conduction spring member with the first contact point is amplified and caused to propagate from the substrate. Thus, the switch unit according to the first embodiment decreases, without undermining switching operability: the contact sound generated at the time when the conduction spring member and the first contact point contact each other; and the sound that is caused when a vibration involved in the collision of the conduction spring member with the first contact point is amplified and caused to propagate from the substrate.
In the switch unit according to the third embodiment of the present application, sound generated near the first contact point is absorbed in, through the connection hole, the cavity extending between the opening formed on the upper surface of the substrate and the inside of the substrate. With this configuration, the switch unit according to the third embodiment decreases: the contact sound generated at the time when the conduction spring member and the first contact point contact each other; and the sound that is caused when a vibration involved in the collision of the conduction spring member with the first contact point is amplified and caused to propagate from the substrate.
In the method for producing the switch substrate according to the present application, an aggregate switch substrate is cut to obtain a switch substrate used in a switch unit having noiselessness. This ensures that a switch substrate used in a switch unit having noiselessness is efficiently produced.
By referring to embodiments and drawings, detailed description will be made below with regard to a switch unit according to the present application and a method according to the present application for producing a switch substrate. It is to be noted that the drawings are schematic representations of a switch unit, a switch substrate, constituent elements of the switch unit and the switch substrate, and peripheral elements of the switch unit and the switch substrate. It is also to be noted that the dimensions and dimension ratios on the drawings may not necessarily be actual dimensions and dimension ratios. It is also to be noted that descriptions deemed redundant will not be repeated, as the case may be, and identical reference numerals will be assigned to identical elements. In the present application, by way of description, vertical directions and lateral directions are defined based on the directions indicated in the drawings, such as
The conduction spring member 15 is out of contact with the first contact point 13 above the first contact point 13_and is in contact with the second contact point 14. Specifically, the conduction spring member 15 is mounted on the upper surface of the second contact point 14 at an outer circumference portion of the conduction spring member 15, and faces the first contact point 13 at a center portion of the conduction spring member 15. The conduction spring member 15 is elastically deformable into contact with the first contact point 13 to make a conduction between the first contact point 13 and the second contact point 14. That is, the conduction spring member 15 serves as a pressing member of the switch unit 11.
The cover sheet 17 is made up of a thin resin sheet of polyimide or phthalamide. On the inner surface of the cover sheet 17, a pressing element 16 is provided in advance. The pressing element 16 is in contact with an apex portion 15a of the conduction spring member 15. The pressing element 16 is provided for the purpose of reinforcing the pressing point of the apex portion 15a. The shape of the pressing element 16 may be other than the cylindrical shape illustrated in
That is, as illustrated in
The substrate 12 includes: the upper hard layer 12a, on which the first contact point 13 and the second contact point 14 are provided; and the lower soft layer 12b. That is, as illustrated in
The first contact point 13 and the second contact point 14 may be prepared by patterning such as etching of an electrode film, such as copper foil, formed on the upper surface of the hard layer 12a. At both end portions of the substrate 12, a first external electrode 20a and a second external electrode 20b are provided respectively. At an inside portion of the substrate 12, a first through-hole electrode 22a and a second through-hole electrode 22b are provided. The first through-hole electrode 22a is electrically connected to the first contact point 13, and the second through-hole electrode 22b is electrically connected to the second contact point 14. That is, the first through-hole electrode 22a and the second through-hole electrode 22b of the switch unit 11 penetrate the substrate 12.
Also, on the lower surface of the substrate 12, that is, on the lower surface of the soft layer 12b, a first wiring pattern 19b and a second wiring pattern 19b are provided. The first wiring pattern 19b is electrically connected to the first external electrode 20a and the first through-hole electrode 22a, and the second wiring pattern 19b is electrically connected to the second external electrode 20b and the second through-hole electrode 22b. The first wiring pattern 19b and the second wiring pattern 19b may be prepared by patterning such as etching of an electrode film, such as copper foil, formed on the lower surface of the soft layer 12b. Also, the first external electrode 20a and the second external electrode 20b may be prepared by patterning such as etching of an electrode film, such as copper foil, formed on the side surfaces of the hard layer 12a and the soft layer 12b.
The conduction spring member 15 is made up of elements such as a metal takt spring having a dome shape. The conduction spring member 15, at its center portion, is out of contact with the first contact point 13 while no external force is being added to the conduction spring member 15. As illustrated in
Since the upper part of the substrate 12 is the hard layer 12a, the first contact point 13 is able to reliably receive the pressing force from the conduction spring member 15. This ensures a stable switching stroke of the switch unit 11, resulting in a reliable switching operation. Also, the soft layer 12b is provided at a lower portion of the hard layer 12a and under the first contact point 13; in the first embodiment, the soft layer 12b is provided immediately under the first contact point 13. This configuration enables the soft layer 12b to absorb: the contact sound generated at the time when the conduction spring member 15 contacts the first contact point 13 (the contact sound generated at the time when the conduction spring member contacts the first contact point will be hereinafter occasionally referred to simply as “contact sound”); and the sound that is caused when a vibration involved in the collision of the conduction spring member 15 with the first contact point 13 amplified and caused to propagate from the substrate 12 (the sound that is caused when a vibration involved in the collision of the conduction spring member with the first contact point is amplified and caused to propagate from the substrate will be hereinafter occasionally referred to as “amplification sound”).
Thus, the switch unit 11 has reliable switchability and noiselessness. It is to be noted that there is no particular limitation to the layer thicknesses of the hard layer 12a and the soft layer 12b. It is preferable, however, that the hard layer 12a has a substantial degree of thickness, since the strength of the substrate as a whole and switching stability depend on the hard layer 12a. In contrast, the soft layer 12b may be thinner than the hard layer 12a, since it is sufficient for the soft layer 12b to be thick enough to absorb the contact sound and the amplification sound generated at the time when the conduction spring member 15 contacts the first contact point.
The hard layer 12a may be made of, for example, glass epoxy resin such as FR-4. The soft layer 12b may be made of, for example, polyimide resin. The soft layer 12b is preferably made of polyimide resin having a Rockwell hardness of from 30 to 130 HRM. It is to be noted that there is no limitation to the materials of the hard layer 12a and the soft layer 12b insofar as the materials have an insulating property and have a hardness approximately equivalent to the hardnesses of glass epoxy resin and polyimide resin.
Similarly to the substrate 12 according to the first embodiment, the soft layer 12b is provided under the first contact point 13; in the second embodiment, the soft layer 12b is provided immediately under the first contact point 13. This configuration enables the soft layer 12b to absorb the contact sound and the amplification sound, keeping the switch unit 31 noiseless. Further, in the switch unit 31, the pair of upper and lower hard layers 12a and 12c receive the press of the conduction spring member 15 to provide excellent click sensitivity.
Also, a hard layer, 12c, is also provided on the lower surface of the soft layer 12b. This improves the workability with which the switch unit 31 is mounted on the mount substrate 23, such as a mother board. Further, at least one of the hard layer 12a and the hard layer 12c may be thinner. Similarly to the first embodiment, the pair of hard layers 12a and 12c and the soft layer 12b may be joined to each other by: radiating ultrasonic or laser to their joint surfaces; or via bonding layers such as binders or bonding sheets (neither of which is illustrated) of epoxy resin or acrylic resin.
As illustrated in
In the third embodiment, in a plan view, the outer circumference of the first contact point 13 is located at a position inner than the right and left outer circumferences 12d′ of the soft layer 12d. Also, the right and left outer circumferences 12d′ of the soft layer 12d are located at positions inner than the right and left outer circumferences 12a′ of the hard layer 12a. More specifically, the right and left outer circumferences 12d′ of the soft layer 12d are located at positions close to and inner than the first external electrode 20a and the second external electrode 20b, which are provided at both end portions of the hard layer 12a. Alternatively, the right and left outer circumferences 12d′ of the soft layer 12d may be located at positions further inner than the first external electrode 20a and the second external electrode 20b; for example, inner than the second contact point 14. The soft layer 12d is joined to the lower surface of the hard layer 12a via a bonding layer 12e, which is a bonding material or a bonding sheet such as epoxy resin and acrylic resin.
The switch unit 41 according to the third embodiment is similar to the switch unit 11 and the switch unit 31 in that the soft layer 12d provided immediately under the first contact point 13 absorbs the contact sound and the amplification sound, ensuring noiselessness of the switch unit 41. Also, the hard layer 12a receives the press of the conduction spring member 15 to enable the switch unit 41 to provide excellent click sensitivity. Also as illustrated in
Further, in the third embodiment, the first wiring pattern 19b and the second wiring pattern 19b are linear patterns which are narrow in width. The wiring pattern area of the first wiring pattern 19b and the second wiring pattern 19b combined is quite smaller than the area of the soft layer 12d. This eliminates or minimizes a situation in which contact sound and amplification sound are generated by the first wiring pattern 19b and the second wiring pattern 19b, which are hard patterns made of copper foil.
In the third embodiment, the first wiring pattern 19b and the second wiring pattern 19b are narrow in width linear patterns so that a shortest connection distance is realized between the first through-hole electrode 22a and the first external electrode 20a and between the second through-hole electrode 22b and the second external electrode 20b. It is possible, however, to set the wiring patterns in any other desired manner in terms of thickness, shape, and area. From the viewpoint of the switch unit 41's noiselessness, however, the wiring pattern area of the first wiring pattern 19b and the second wiring pattern 19b combined is preferably smaller than the area of the soft layer 12d.
The through hole 53 is preferably positioned immediately under the first contact point 13. The shape of the through hole 53 may be a circular shape or a polygonal shape such as a rectangle. In the fourth embodiment, the substrate 52 has a two-layer structure made up of the hard layer 12a and the soft layer 12f, and the through hole 53 of the soft layer 12f is provided immediately under the first contact point 13. This configuration enables the soft layer 12f to absorb the contact sound and the amplification sound. Further, the contact sound and the amplification sound can be externally released through the through hole 53. This increases the reliability with which noiselessness of the switch unit 51 is ensured. It is to be noted that the soft layer 12f is joined to the lower surface of the hard layer 12a via the bonding layer 12e.
As illustrated in
The switch units 11, 31, 41, 51, 61, 71, and 81 are also applicable to switch devices using lead frames.
The first contact point 13 is provided on the upper surface of the substrate 92 and above the soft layer 12k. The first contact point 14 is provided on the upper surface of the substrate 92 and around the first contact point 14. The conduction spring member 15 is provided above the first contact point 13 in a non-contact state with the first contact point 13, and in a contact state with the second contact point 14. And the conduction spring member 15 is elastically deformable into contact with the first contact point 13 to make a conduction between the first contact point 13 and the second contact point 14. The first external electrode 27a and the second external electrode 27b are provided at end portions of the substrate 92.
The first connection electrode 28a is provided at an inside portion of the substrate 92, and electrically connects the first contact point 13 and the first external electrode 27a to each other. The second connection electrode 28b is provided at an inside portion of the substrate 92, and electrically connects the second contact point 14 and the second external electrode 27b to each other. The switch unit 91 is mounted on the mount substrate 23, such as a mother board, via the soft layer 12k. In the switch unit 91, since the soft layer 12k is provided under the first contact point 13, the soft layer 12k reliably absorbs the contact sound and the amplification sound.
By referring to
The aggregate substrate 45 is made up of a hard layer 12a. The plurality of first contact points 13 are provided on the upper surface of the aggregate substrate 45. The plurality of second contact points 14 are provided on the upper surface of the aggregate substrate 45 and provided around the respective first contact points 13. The plurality of first through-hole electrodes 22a are provided at an inside portion of the aggregate substrate 45 and electrically connected to the respective first contact points 13. The plurality of second through-hole electrodes 22b are electrically connected to the respective second contact points 14.
The plurality of through holes 46 extend between the upper surface and the lower surface of the aggregate substrate 45, and conduction layers 47 are provided on the side surfaces of the through holes 46. The plurality of first wiring patterns 19a are provided on the lower surface of the aggregate substrate 45 and electrically connected to the respective conduction layers 47 and the respective first through-hole electrodes 22a. The plurality of second wiring patterns 19b are electrically connected to the respective conduction layers 47 and the respective second through-hole electrodes 22b. The method for producing the switch substrate 43 includes a forming step and a cutting step.
In the forming step, an aggregate switch substrate 49 is obtained by forming a soft layer 48 on the lower surface of the aggregate switch substrate member 44 in such a manner that the soft layer 48 covers a portion located at least immediately under the plurality of first contact points 13 and does not cover the plurality of through holes 46.
The switch substrate 43 thus obtained includes: a substrate 45′, which includes the hard layer 12a and the soft layer 48; the first contact point 13; the second contact point 14; the first through-hole electrode 22a; the second through-hole electrode 22b; the first external electrode 20a; the second external electrode 20b; the first wiring pattern 19a; and the second wiring pattern 19b. The forming step may include a step of bonding, to the lower surface of the aggregate switch substrate member 44, a plurality of soft plates 48′ in a stripe arrangement. The soft plates 48′ are made up of the soft layer 48. By this step, the soft layer 48 is efficiently formed on the lower surface of the aggregate substrate 45, which is made up of the hard layer 12a.
The substrate 112 includes: a cavity 132, which is formed inside the substrate 112; an opening 134, which is formed on the upper surface of the substrate 112, and a connection hole 133a, which connects the opening 134 and the cavity 132 to each other. The first contact point 13 is provided on the upper surface of the substrate 112. The second contact point 14 is provided around the first contact point 13. The conduction spring member 15′ is provided above the first contact point 13 in a non-contact state with the first contact point 13 and in a contact state with the second contact point 14. And the conduction spring member 15′ is elastically deformable into contact with the first contact point 13 to make a conduction between the first contact point 13 and the second contact point 14. The second contact point 14 is electrically connected to the external electrode 19 via a through hole 22, which penetrates the substrate 112.
As illustrated in
The opening 134, the connection hole 133a, and the cavity 132 constitute a silencer 131a. Also, the opening 134, the connection hole 133b, and the cavity 132 constitute a silencer 131b. The silencer 131a is formed based on the principle of a Helmholtz resonator. An operation of the silencer 131a will be described below by referring to
The connection hole 133a of the silencer 131a illustrated in
The first substrate member 112a and the second substrate member 112b may be joined to each other by radiating ultrasonic and/or laser to their joint surfaces after positioning the cavity 132 and the connection hole 133a. Also, the first substrate member 112a and the second substrate member 112b may be joined to each other via a binder or a bonding sheet (neither of which is illustrated) of epoxy resin or acrylic resin. The first contact point 13 and the second contact point 14 are formed by patterning such as etching of an electrode film formed on the upper surface of the first substrate member 112a.
Also, the first contact point 13 and the second contact point 14 are electrically connected to a first external electrode 119 and a second external electrode 20 through the through hole 122, which penetrates the substrate 112. The first external electrode 119 and the second external electrode 20 are formed on the lower surface of the second substrate member 112b. The first external electrode 119 and second external electrode 20 are formed by patterning such as etching of an electrode film formed on the lower surface of the second substrate member 112b.
The connection hole 133a is formed by a quantity corresponding to the quantity of the cavity 132, and each one cavity 132 is connected to a corresponding one connection hole 133a. In one example, a pair of silencers 131a are provided at positions where the silencers 131a face each other across the first contact point 13, where contact sound is generated. Each silencer 131a is independently formed and made up of one cavity 132 and one connection hole 133a. The cavities 132 may be identical to each other in terms of capacity. The connection holes 133a may be identical to each other in terms of the length. The openings 134 may be identical to each other in terms of the diameter. While the tenth embodiment is an example in which a pair of silencers 131a are provided, at least one silencer 131a suffices to decrease the contact sound generated by the contact between the first contact point 13 and the conduction spring member 15. Further, by providing three or more silencers 131a along the circumference of the first contact point 13, the contact sound generated by the contact between the first contact point 13 and the conduction spring member 15 is further decreased.
The first substrate member 112a according to the eleventh embodiment is the same as the first substrate member 112a according to the tenth embodiment. By providing a larger depression at a center portion of the second substrate member 112b, the area of the circular cavity 132b is made larger than the area of the first contact point 13. Thus, by increasing the capacity of the cavity 132b, a larger amount of inflowing air is pressed into the cavity 132b through the plurality of connection holes 133a, and the air pressed into the cavity 132b causes a larger level of vibration to be generated. This decreases the sound emitted externally from the cavity 132b through each connection hole 133a. It is to be noted that each connection hole 133a according to the eleventh embodiment may be formed in a direction perpendicular or inclined relative to the upper surface of the first substrate member 112a, similarly to the connection holes 133a and 133b according to the tenth embodiment. The connection holes according to the twelfth to fifteenth embodiments may also be formed in a direction perpendicular or inclined relative to the upper surface of the first substrate member.
In the fourteenth embodiment, it is possible to provide three or more connection holes 143 surrounding the first contact point 13, with the planar space defined in the cavity 142b taken into consideration. Thus, by providing a plurality of connection holes 143, the contact sound generated by the contact between the first contact point 13 and the conduction spring member 15 is further decreased. It is to be noted that the cavity 142b may have an area of space large enough to be connected to more than one connection hole 143. Therefore, the shape of the cavity 142b will not be limited to a quadrangular shape but may be any other polygonal shape than a quadrangular shape or may be a circular shape.
A cavity 162 is a spacious circular cavity and formed immediately under the first contact point 13. In the first substrate member 112a, a connection hole 163 is provided. The connection hole 163 connects the cavity 162 and the opening 164 to each other. In a silencer 161 according to the fifteenth embodiment, the ratio of the area of the cavity 162 to the area of the second substrate member 112b as a whole is large. With this configuration, the silencer 161 is more suitable for a small-size substrate in which the space between the first contact point 13 and the second contact point 14 is small.
In all the tenth to sixteenth embodiments, a two-layer substrate made up of the first substrate member 112a and the second substrate member 112b is used. Alternatively, it is possible to use a three-layer substrate formed by mounting a third substrate member 112c on a lower portion of the second substrate member 112b. In this case, a cavity 172 is formed in the second substrate member 112b, and the lower surface of the cavity 172 is defined by the upper surface of the third substrate member 112c. A through hole serving as the cavity 172 is defined by the second substrate member 112b, and the third plate 12c is provided under the cavity 172. This configuration ensures that a silencer 171 is easily formed including an opening 174, a connection hole 173, and the bottomed cavity 172.
It is preferable that the cavity 172 and the connection hole 173, which constitute the silencer 171, are sealed. In light of this, the materials of the first substrate member 112a, the second substrate member 112b, and the third substrate member 112c are preferably high-density hard materials such as glass epoxy substrate (FR-4). Using such hard members prevents the conduction spring member 15 from being kept in depressed state toward the first contact point 13, and provides a moderate level of click sensitivity. This improves the switch unit's switching accuracy.
In conventional noiseless switch units, a shock-absorbing material is provided on the substrate or the substrate itself is made of a noiseless material, in order to alleviate the contact sound caused by switching. In a switch unit according to an embodiment of the present application, even though the switch unit is small and thin, a through hole or a depression having different opening widths are formed in the substrate having a multilayer structure such as a two-layer or three-layer structure. This ensures that the switch unit provides a silencing effect that is based on a Helmholtz resonator principle, which promotes positive absorption of sounds. The switch units according to the tenth to sixteenth embodiment and the switch units according to other embodiments including a three-layer substrate are also applicable to switch devices using lead frames.
It is possible to: form a large-size aggregate first substrate in which a plurality of first substrate members 112a can be formed; form a large-size aggregate second substrate in which a plurality of second substrate members 112b can be formed; stack the aggregate first substrate on the aggregate second substrate; and subject the substrate to dicing along a predetermined region. As a result, substrates 112 corresponding to respective switch units 111 according to the tenth embodiment can be formed collectively. The first substrate member 112a and the second substrate member 112b may be flexible substrates. An example is illustrated in
In this example, an aggregate first substrate 182a has a plurality of connection holes 133a, and an aggregate second substrate 182b has a plurality of cavities 132 and a lead portion 183. The aggregate first substrate 182a is joined on the aggregate second substrate 182b. The aggregate first substrate 182a and the aggregate second substrate 182b that have been joined to each other are cut from the lead portion 183 and divided into regions of individual switch units 111, which is not illustrated. It is to be noted that this aggregate substrate may also be used to form the substrate having the layer structure illustrated in
By referring to
In the joining step, the aggregate switch substrate 149 is obtained by joining a first aggregate substrate 191 and a second aggregate substrate 192 to each other. On the upper surface of the first aggregate substrate 191, a plurality of first contact points 13 and a plurality of second contact points 14 are formed. The plurality of second contact points 14 are provided around the respective first contact points 13. The first aggregate substrate 191 has a plurality of through holes 146. The second aggregate substrate 192 has a plurality of cavities 132. The maximum value of a sectional area of each cavity 132 parallel to the upper surface of the first aggregate substrate 191 is larger than the maximum value of a sectional area of each through hole 146 parallel to the upper surface of the first aggregate substrate 191. Each of the cavities 132 is open only on the upper surface of the second aggregate substrate 192. The plurality of through holes 146 overlap the plurality of respective cavities 132 in a vertical direction. In the cutting step, the aggregate switch substrate 149 is cut to obtain individual switch substrates 148. Between the joining step and the cutting step, it is possible to perform a forming step of forming a plurality of resin layers in a stripe arrangement on the lower surface of the aggregate switch substrate 149.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-145733 | Aug 2018 | JP | national |
| 2018-218997 | Nov 2018 | JP | national |
| 2019-005118 | Jan 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/030147 | 8/1/2019 | WO | 00 |
