Dome switch

BACKGROUND OF THE INVENTION

The present invention relates to a dome switch including a surface sheet having a dome-shaped protuberance, a spacer sheet, the circuit member, and an adhesive sheet.

FIG. 15

is an exploded perspective view of a poly-dome switch (dome switch) in a related art,

FIG. 16

is a cross-sectional view of essential portions before the switching operation, and

FIG. 17

is a cross-sectional view of the essential portions at the time of the switching operation.

In

FIG. 15

, a related poly-dome switch (dome switch)

1

used in a household electric appliance includes a surface sheet

2

, a spacer sheet

3

, a flexible printed circuit (FPC)

4

, and an adhesive sheet

5

, and is fixed to a plate

6

serving as an attaching member to be attached to with the adhesive sheet

5

interposed.

A plurality of dome-shaped protuberances

7

which project toward the outer surface side and are capable of being reversed toward the inner surface side are formed in the aforementioned surface sheet

2

. Electrodes

8

(see

FIG. 16

) for the FPC

4

are respectively provided on the inner surfaces of the protuberances

7

.

The spacer sheet

3

is a thin sheet member and is provided to prevent the deformation of the surface sheet

2

. The spacer sheet

3

is provided with adhesive layers on its obverse and reverse surfaces, so that the surface sheet

2

and the FPC

4

can be fixed thereto. A plurality of through holes

9

are formed in the spacer sheet

3

in such a manner as to correspond to the positions of the protuberances

7

. Further, slit-like air release portions

10

are respectively formed on both sides of the through holes

9

.

The FPC

4

is a circuit member having a plurality of circuits routed in desired patterns. A plurality of contacts

11

which are contacted by the electrodes

8

(see

FIG. 16

) are provided on its spacer sheet

3

side. The FPC

4

is bonded and fixed to the adhesive sheet

5

. The adhesive sheet

5

has the function as a reinforcing member.

In the above-described construction, the poly-dome switch

1

operates such that, as shown in

FIG. 17

, when the protuberance

7

is pressed down to effect a switching operation, the protuberance

7

is reversed toward the FPC

4

(the feeling of a click occurs at this time), and the electrode

8

is brought into contact with the contact

11

to energize the circuit. It should be noted that when the protuberance

7

is reversed toward the FPC

4

, the air located on the inner surface side of the protuberance

7

is vented to the air release portions

10

through the through hole

9

.

In the above-described poly-dome switch

1

, the structure provided is such that the spacer sheet

3

and the FPC

4

are brought into surface contact with each other. For this reason, there has been a problem in that when an attempt is made to mount chip components on the FPC

4

and assemble them, the spacer sheet

3

is lifted off the FPC

4

and becomes deformed due to the effect of the height of the chip components. Incidentally, if the spacer sheet

3

is lifted off and becomes deformed, the switching function is naturally affected.

SUMMARY OF THE INVENTION

The invention has been devised in view of the above-described circumstances, and its object is to provide a chip-component accommodating structure in a dome switch which makes it possible to mount a chip component on a circuit member.

In order to solve the aforesaid object, the invention is characterized by having the following arrangement.

(1) A dome switch comprising:

a front sheet;

a dome-shaped protuberance which is formed on the front sheet so as to protrude outside, can be reversed inside and includes an electrode provided therein;

a circuit member having a contact point with which the electrode are brought into contact when the protuberance is reversed;

a spacer sheet which is interposed between the front sheet and the circuit member, and includes a through hole formed therein for ensuring contact between the electrode and the contact point;

an adhesive sheet including on one side a circuit attaching surface for the circuit member and on the other side a bonding and fixing surface for an attaching member; and

a spacer sheet-side accommodating portion, for accommodating a chip component mounted on a side of the circuit member where the contact is disposed, formed in the spacer sheet.

(2) The dome switch according to (1), wherein an embossed portion for the chip component is formed in the surface sheet in correspondence with a position of the spacer sheet-side accommodating portion.

(3) A dome switch comprising:

a front sheet;

a dome-shaped protuberance which is formed on the front sheet so as to protrude outside, can be reversed inside and includes an electrode provided therein;

a circuit member having a contact point with which the electrode are brought into contact when the protuberance is reversed;

a spacer sheet which is interposed between the front sheet and the circuit member, and includes a through hole formed therein for ensuring contact between the electrode and the contact point;

an adhesive sheet including on one side a circuit attaching surface for the circuit member and on the other side a bonding and fixing surface for an attaching member; and

an adhesive sheet-side accommodating portion, for accommodating a chip component mounted on a side of the circuit member where the contact is not disposed, formed in the adhesive sheet.

(4) The dome switch according to (3), wherein a recessed portion for the chip component is formed in the attaching member in correspondence with a position of said adhesive sheet-side accommodating portion.

(5) A dome switch comprising:

a front sheet;

a dome-shaped protuberance which is formed on the front sheet so as to protrude outside, can be reversed inside and includes an electrode provided therein;

a circuit member having a contact point with which the electrode are brought into contact when the protuberance is reversed;

a spacer sheet which is interposed between the front sheet and the circuit member, and includes a through hole formed therein for ensuring contact between the electrode and the contact point;

an adhesive sheet including on one side a circuit attaching surface for the circuit member and on the other side a bonding and fixing surface for an attaching member;

a spacer sheet-side accommodating portion, for accommodating a chip component mounted on a side of the circuit member where the contact is disposed, is formed in the spacer sheet; and

an adhesive sheet-side accommodating portion, for accommodating a chip component mounted on a side of the circuit member opposite to the side where the contact is disposed, is formed in the adhesive sheet.

(6) The dome switch according to (5), wherein an embossed portion for the chip component is formed in the surface sheet in correspondence with a position of the spacer sheet-side accommodating portion.

(7) The dome switch according to (5), wherein a recessed portion for the chip component is formed in the attaching member in correspondence with a position of the adhesive sheet-side accommodating portion.

(8) A dome switch comprising:

a front sheet;

a dome-shaped protuberance which is formed on the front sheet so as to protrude outside, can be reversed inside and includes an electrode provided therein;

a circuit member having a contact point with which the electrode are brought into contact when the protuberance is reversed;

a spacer sheet which is interposed between the front sheet and the circuit member, and includes a through hole formed therein for ensuring contact between the electrode and the contact point;

a light guiding portion, for accommodating and light guidance for a LED mounted on a side of the circuit member where the contact is disposed, formed in the spacer sheet; and

a light emitting portion, which is illuminated by light from the LED and through which the light can pass, formed in the surface sheet.

(9) The dome switch according to (8), wherein a light diffusing member for diffusing the light from the LED toward the light emitting portion is formed between the light guiding portion and the light emitting portion.

(10) The dome switch according to (8), further comprising:

an adhesive sheet having on one side a circuit attaching surface for the circuit member and on the other side a bonding and fixing surface for an attaching member; and

an external connection member provided on the circuit member so as to be used for electrical connection to an external circuit.

(11) The dome switch according to (10), wherein the external connection member includes edge connector terminals or a connector.

(12) The dome switch according to (11), wherein the external connection member includes a connection circuit portion led out from a circuit member body.

(13) The dome switch according to (10), wherein the adhesive sheet includes a release paper on the bonding and fixing surface.

(14) A dome switch comprising:

a front sheet;

a dome-shaped protuberance which is formed on the front sheet so as to protrude outside, can be reversed inside and includes an electrode provided therein;

a circuit member having a contact point with which the electrode are brought into contact when the protuberance is reversed;

a spacer sheet which is interposed between the front sheet and the circuit member, and includes a through hole formed therein for ensuring contact between the electrode and the contact point;

a light guiding portion, for accommodating and light guidance for a LED mounted on a side of the circuit member where the contact is disposed, formed in the spacer sheet;

a light collecting portion, for collecting the light guided by the light guiding portion, formed in the spacer sheet; and

a light emitting portion, which is illuminated by collected light from the light collecting portion and through which the light can pass, formed in the surface sheet.

(15) The dome switch according to (14), wherein a reflector is provided on obverse and reverse surfaces of the spacer sheet or on the inner surface of the surface sheet and the side of the circuit member where the contact is disposed.

(16) The dome switch according to (14), further comprising:

an adhesive sheet having on one side a circuit attaching surface for the circuit member and on the other side a bonding and fixing surface for an attaching member; and

an external connection member provided on the circuit member so as to be used for electrical connection to an external circuit.

(17) The dome switch according to (16), wherein the external connection member includes edge connector terminals or a connector.

(18) The dome switch according to (179, wherein the external connection member includes a connection circuit portion led out from a circuit member body.

(19) The dome switch according to (16), wherein the adhesive sheet includes a release paper on the bonding and fixing surface.

In accordance with the intention, in the assembly of the dome switch, the chip component mounted on the contact side of the circuit member is accommodated in the spacer sheet-side accommodating portion of the spacer sheet. By forming the spacer sheet-side accommodating portion in the spacer sheet, it becomes possible to mount the chip component on the contact side of the circuit member.

In accordance with the invention, in the assembly of the dome switch, the chip component mounted on a side of the circuit member opposite to its side where the contact is formed is accommodated in the adhesive sheet-side accommodating portion of the adhesive sheet. By forming the adhesive sheet-side accommodating portion in the adhesive sheet, it becomes possible to mount the chip component on the side of the circuit member opposite to the side where the contact is disposed.

In accordance with the invention, in the assembly of the dome switch, the chip component mounted on the contact side of the circuit member is accommodated in the spacer sheet-side accommodating portion of the spacer sheet. In addition, the chip component mounted on a side of the circuit member opposite to its side where the contact is formed is accommodated in the adhesive sheet-side accommodating portion of the adhesive sheet. By forming the spacer sheet-side accommodating portion in the spacer sheet, it becomes possible to mount the chip component on the contact side of the circuit member. Further, by forming the adhesive sheet-side accommodating portion in the adhesive sheet, it becomes possible to mount the chip component on the side of the circuit member opposite to the side where the contact is disposed.

In accordance with the invention, in a case where the height of the chip component mounted on the contact side of the circuit member is large, a tip portion of the chip portion is accommodated in the embossed portion of the surface sheet. By forming the embossed portion in the surface sheet, it becomes possible to mount the chip component with large height on the contact side of the circuit member.

In accordance with the invention, in a case where the height of the chip component mounted on the side of the circuit member opposite to the side where the contact is disposed is large, a tip portion of the chip portion is accommodated in the recessed portion of the attaching member. By forming the recessed portion in the attaching member, it becomes possible to mount the chip component with large height on the side of the circuit member opposite to the side where the contact is disposed.

In accordance with the invention, in the poly-dome switch, the LED is mounted on the circuit member. If the LED is made to emit light, the light from the LED is guided through the light guiding portion in the spacer sheet, and the light emitting portion of the surface sheet is illuminated. Further, the light emitting portion, as it were, emits light due to the light which passed through the light emitting portion. Meanwhile, in the assembly of the dome switch, the LED mounted on the circuit member is accommodated in the light guiding portion of the spacer sheet. By forming the light guiding portion in the spacer sheet, it becomes possible to mount the LED on the contact side of the circuit member.

In accordance with the invention, if the LED is made to emit light, the light emitting portion of the surface sheet is illuminate by the diffused light. Consequently, the light emitting portion is prevented from becoming partially bright.

In accordance with the invention, in the poly-dome switch, the LED is mounted on the circuit member. If the LED is made to emit light, the light from the LED is guided through the second light guiding portion and the light collecting portion in the spacer sheet, and the second light emitting portion of the surface sheet is illuminated. Further, the second light emitting portion, as it were, emits light due to the light which passed through the second light emitting portion. Meanwhile, in the assembly of the dome switch, the LED mounted on the circuit member is accommodated in the second light guiding portion of the spacer sheet. By forming the second light guiding portion in the spacer sheet, it becomes possible to mount the LED on the contact side of the circuit member.

In accordance with the invention, the light is efficiently guided between the second light guiding portion and the light collecting portion by the reflector.

In accordance with the invention, the adhesive sheet is further provided in the arrangement, and since the circuit member has the external connection member, the dome switch can be installed at a position which meets the user's need. In addition, fixation is effected by merely attaching the bonding and fixing surface to the attaching member, so that the dome switch can be easily installed.

In accordance with the invention, electrical connection to an external circuit is effected by the edge connector terminals or the connector.

In accordance with the invention, electrical connection to an external circuit is made within the range of the length of the connection circuit portion led out from the circuit member body

In accordance with the invention, the bonding and fixing surface is protected up until the time of final use. In addition, the switch can be carried in a state in which the release paper is provided on the bonding and fixing surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is an exploded perspective view illustrating a first embodiment of a chip-component accommodating structure in a dome switch in accordance with the invention;

FIG. 2

is an enlarged cross-sectional view of a chip-component accommodating portion shown in

FIG. 1

;

FIG. 3

is an exploded perspective view illustrating a second embodiment of the chip-component accommodating structure in a dome switch in accordance with the invention;

FIG. 4

is an enlarged cross-sectional view of the chip-component accommodating portion shown in

FIG. 3

;

FIG. 5

is an exploded perspective view illustrating a third embodiment of the chip-component accommodating structure in a dome switch in accordance with the invention;

FIG. 6

is an exploded perspective view illustrating a fourth embodiment of a dome switch in accordance with the invention;

FIG. 7

is an enlarged cross-sectional view of an LED mounting portion shown in

FIG. 6

;

FIG. 8

is an exploded perspective view illustrating a specific example of mounting the dome switch;

FIG. 9

is an exploded perspective view illustrating a specific example of mounting the dome switch;

FIG. 10

is an exploded perspective view illustrating a fifth embodiment of the dome in accordance with the invention;

FIG. 11

is an enlarged plan view of a spacer sheet shown in

FIG. 10

;

FIG. 12

is an enlarged cross-sectional view of the LED mounting portion shown in rig.

10

;

FIG. 13

is a perspective view for explaining another example of an external connection member;

FIG. 14

is a perspective view for explaining another example of the external connection member;

FIG. 15

is an exploded perspective view of a poly-dome switch (dome switch) in a related art;

FIG. 16

is a cross-sectional view of essential portions before the switching operation in

FIG. 15

; and

FIG. 17

is a cross-sectional view of the essential portions at the time of the switching operation in FIG.

15

.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the accompanying drawings, a description will be given of an embodiment of the invention.

First Embodiment

FIG. 1

is an exploded perspective view illustrating a first embodiment of a chip-component accommodating structure in a dome switch in accordance with the invention.

FIG. 2

is an enlarged cross-sectional view of a chip-component accommodating portion shown in FIG.

1

.

In

FIG. 1

, a poly-dome switch

21

(corresponding to the dome switch in the claims) is constituted by a surface sheet

22

, a spacer sheet

23

, a flexible printed circuit (FPC)

24

, and an adhesive sheet

25

. The poly-dome switch

21

is fixed to a plate

26

serving as an example of an attaching member to be attached to by the adhesive sheet

25

. In the first embodiment of the invention, the chip-component accommodating structure is formed in the surface sheet

22

and the spacer sheet

23

.

The surface sheet

22

includes a plurality of protuberances

27

and an embossed portion

28

constituting the aforementioned chip-component accommodating structure. Each of protuberances

27

is formed in a dome shape so as to project toward outside and is capable of being reversed toward inside. An electrode

29

(see

FIG. 2

) for the FPC

24

is provided on the inner surface of each protuberance

27

. The electrode

29

is provided on a top portion of the inner surface.

The embossed portion

28

is formed in the shape of a rectangular dome (it should be construed that the shape is not limited to this shape) projecting toward the outer surface side in the same way as the protuberance

27

. The embossed portion.

28

is formed in correspondence with the mounting position of chip components

38

which will be described later. The embossed portion

28

is formed in such a manner as to be capable of accommodating tips of the chip components

38

, as will be described later. It should be noted that the embossed portion

28

need not be capable of being reversed like the protuberance

27

.

The surface sheet

22

will be described in detail. The surface sheet

22

is a synthetic resin-made sheet formed of polyethylene terephthalate (PET), for example, and includes the plurality of dome-shaped protuberances

27

and the rectangular dome-shaped embossed portion

28

which are formed by being subjected to heat pressing (by applying pressure from the inner surface side toward the outer surface side) The electrodes

29

provided on top portions of the inner surfaces of the protuberances

27

are formed of carbon or the like (the electrodes

29

formed of carbon are provided by printing).

The spacer sheet

23

is constituted by an upper-layer spacer sheet

30

and two lower-layer spacer sheets

31

. Namely, the spacer sheet

23

is constituted by three layers (the spacer sheet

23

need not necessarily be formed in three layers, and may be formed in a single layer, two layers, or four or more layers; if the spacer sheet

23

is formed in a plurality of layers, there is an advantage that the spacer sheet can be provided with more flexibility than in the case of a single layer). The spacer sheet

23

is adapted to function as a member for preventing the deformation of the surface sheet

22

.

The upper-layer spacer sheet

30

is a synthetic resin-made sheet formed of polyethylene terephthalate (PET), for example, and the upper-layer spacer sheet

30

is formed to be thinner than the lower-layer spacer sheets

31

. Namely, the upper-layer spacer sheet

30

functions as a fine-adjustment sheet member for adjusting the thickness of the spacer sheet

23

. In addition, the upper-layer spacer sheet

30

has layers of an unillustrated adhesive agent on its obverse and reverse surfaces, so that the surface sheet

22

and the lower-layer spacer sheet

31

can be fixed to its obverse and reverse surfaces, respectively.

The upper-layer spacer sheet

30

will be described in detail. The upper-layer spacer sheet

30

has a plurality of through holes

32

, a plurality of air release portions

33

, and an accommodating portion

34

(corresponding to a spacer sheet-side accommodating portion stated in the claims) constituting the aforementioned chip-component accommodating structure. Each through hole

32

is a portion for ensuring contact between the electrode

29

of the protuberance

27

and a contact

37

(which will be described later) of the FPC

24

, and is formed in conformity with the position of the corresponding protuberance

27

. Each through hole

32

is formed to have a diameter greater than or equal to the diameter of the protuberance

27

(see FIG.

2

).

Each of the air release portions

33

is a portion which allows the air located on the inner surface side to be released appropriately when each protuberance

27

is reversed. The air release Portions

33

are formed between adjacent ones of the through holes

32

arranged in the longitudinal direction in the upper-layer spacer sheet

30

. Each of the air release portions

33

is formed in the shape of a slit in such a manner as to communicate with the corresponding through holes

32

.

The accommodating portion

34

is formed in a rectangular shape in correspondence with the mounting position of the chip components

38

, as will be described later.

Each of the lower-layer spacer sheets

31

is a synthetic resin-made sheet formed of polyethylene terephthalate (PET), for example, and includes unillustrated adhesive layers on its obverse and reverse surfaces, so that after their lamination the upper-layer spacer sheet

30

and the FPC

24

can be fixed to the obverse and reverse surfaces, respectively. The lower-layer spacer sheets

31

includes the through holes

32

, the air release portions

33

, and the accommodating portion

34

provided in the same numbers and having the same shapes, positions, and function as those of the upper-layer spacer sheet

30

. Incidentally, these members will be denoted by the same reference numerals as those of the upper-layer spacer sheet

30

, and a description thereof will be omitted. It should be noted that the diameter of each through hole

32

in each lower-layer spacer sheet

31

is formed to be greater than or equal to the diameter of each through hole

32

in the upper-layer spacer sheet

30

. It goes without saying that if the diameter of each through hole

32

in each spacer sheet

31

becomes large, the space concerning the venting of air can be made large, and the feeling of a click at the time of the switching operation improves.

The aforementioned FPC

24

is a circuit member including a plurality of circuits

35

routed in desired patterns, and two air vents

36

communicating with the air release portions

33

in the respective layers of the spacer sheet

23

are formed in its central portion. The plurality of contacts

37

with which the electrodes

29

(see

FIG. 2

) are brought into contact are disposed on the spacer sheet

23

side of the FPC

24

. The plurality of chip components

38

are mounted on the spacer sheet

23

side (contact

37

side) of the FPC

24

. Incidentally, the circuit member is not confined to the FPC (FPC

24

)

The adhesive sheet

25

is formed so as to be able to bond and fix the FPC

24

. The adhesive sheet

25

is formed so as to be bonded and fixed to the plate

26

. Namely, the adhesive sheet

25

includes on one side a circuit attaching surface for the FPC

24

and on its other side a bonding and fixing surface for the plate

26

. The adhesive sheet

25

functions as a reinforcing member. Two air vents

39

communicating with the air vents

36

in the FPC

24

and similar thereto are formed in the adhesive sheet

25

.

The plate

26

includes an attaching surface

40

to which the bonding and fixing surface of the adhesive sheet

25

adheres. Two space portions

41

having, for example, U-shaped cross sections are arranged and formed in the attaching surface

40

. The space portions

41

are communicated with the air release portions

33

in the spacer sheet

23

through the air vents

36

in the FPC

24

and the air vents

39

in the adhesive sheet

25

(the air vents

36

in the FPC

24

and the air vents

39

in the adhesive sheet

25

function as passages for communication with the air release portions

33

in the spacer sheet

23

and the space portions

41

in the plate

26

). It should be noted that the plate

26

in terms of its shape may be formed in the shape of a housing like a switch casing.

Reference numeral

42

denotes a light emitting diode (LED) mounted on the spacer sheet

23

side (contact

37

side) of the FPC

24

. Reference numeral

43

in each of the lower-layer spacer sheets

31

denotes a light guiding portion for the LED

42

. Each of the light guiding portions

43

is formed so as to have an accommodating structure (application of the invention) for the LED

42

. Reference numeral

44

in the upper-layer spacer sheet

30

denotes a diffusing means

44

for diffusing the light from the LED

42

. Reference numeral

45

in the surface sheet

22

denotes a light emitting portion which is illuminated by the light from the LED

42

and where the light passes.

In the above-described construction, the poly-dome switch

21

is assembled as follows: First, the upper-layer spacer sheet

30

and the lower-layer spacer sheets

31

are bonded and fixed together to form the spacer sheet

23

. Next, the surface sheet

22

is bonded and fixed to the surface (actually, the upper-layer spacer sheet

30

) of the spacer sheet

23

, and the FPC

24

is bonded and fixed to the revere surface (actually, the lowermost lower-layer spacer sheet

31

) of the spacer sheet

23

, so that the plurality of chip components

38

.mounted on the spacer sheet

23

side (contact

37

side) of the FPC

24

are accommodated in the accommodating portions

34

of the upper-layer spacer sheet

30

and the lower-layer spacer sheets

31

(see FIG.

2

). Subsequently, the FPC

24

side of this subassembly is bonded and fixed to the circuit attaching surface of the adhesive sheet

25

, thereby completing the assembly. It should be noted that the assembled poly-dome switch

21

is mounted by causing the bonding and fixing surface of the adhesive sheet

25

to adhere to the attaching surface

40

of the plate

26

.

As described above, the poly-dome switch

21

in accordance with the first embodiment has the chip-component accommodating structure which allows the plurality of chip components

38

mounted on the'spacer sheet

23

side (contact

37

side) of the FPC

24

to be accommodated in the accommodating portions

34

of the upper-layer spacer sheet

30

and the lower-layer spacer sheets

31

and in the embossed portion

28

of the surface sheet

22

. Consequently, even if the chip components

38

are mounted on the FPC

24

, the spacer sheet

23

is prevented from becoming lifted off the FPC

24

and deformed. Accordingly, even if the chip components

38

are mounted on the FPC

24

, the switching function is not affected.

Second Embodiment

Next, referring to

FIG. 3

, a description will be given of the chip-component accommodating structure in a done switch in accordance with a second embodiment.

FIG. 3

is an exploded perspective view illustrating the second embodiment of the chip-component accommodating structure in a dome switch. It should be noted that portions which are basically identical to the portions of the above-described component members will be denoted by the same reference numerals, and a description thereof will be omitted.

In

FIG. 3

, a poly-dome switch

51

(corresponding to the dome switch stated in the claims) is constituted by a surface sheet

52

, a spacer sheet

53

, a flexible printed circuit (FPC)

54

, and an adhesive sheet

55

. The poly-dome switch

51

is fixed to a plate

56

serving as, for example, the attaching member to be attached to by the adhesive sheet

55

. In the second embodiment of the invention, the chip-component accommodating structure is formed in the adhesive sheet

55

and the plate

56

.

The surface sheet

52

is a synthetic resin-made sheet formed of polyethylene terephthalate (PET), for example, and includes the plurality of protuberances

27

. The electrodes

29

(see

FIG. 4

) for the FPC

54

are provided on the inner surfaces of the protuberances

27

. The electrodes

29

(see

FIG. 2

) are provided on top portions of the inner surfaces.

The spacer sheet

53

comprises an upper-layer spacer sheet

57

and two lower-layer spacer sheets

58

. Namely, the spacer sheet

53

is formed in three layers (in the same way as the aforementioned spacer sheet

23

the spacer sheet

53

need not necessarily be formed in three layers, and may be formed in a single layer, two layers, or four or more layers). In addition, the spacer sheet

53

is adapted to function as a member for preventing the deformation of the surface sheet

52

.

The upper-layer spacer sheet

57

is a synthetic resin-made sheet formed of polyethylene terephthalate (PET), for example, and the upper-layer spacer sheet

57

is formed to be thinner than the lower-layer spacer sheets

58

. Namely, the upper-layer spacer sheet

57

functions as a fine-adjustment sheet member for adjusting the thickness of the spacer sheet

53

. The upper-layer spacer sheet

57

has layers of an unillustrated adhesive agent on its obverse and reverse surfaces, so that the surface sheet

52

and the lower-layer spacer sheet

58

can be fixed to its obverse and reverse surfaces, respectively. The upper-layer spacer sheet

53

includes the plurality of through holes

32

and the plurality of air release portions

33

.

Each of lower-layer spacer sheets

58

is a synthetic resin-made sheet formed of polyethylene terephthalate (PET), for example, and includes unillustrated adhesive layers on its obverse and reverse surfaces, so that after their lamination the upper-layer spacer sheet

57

and the FPC

54

can be fixed to the obverse and reverse surfaces, respectively. The lower-layer spacer sheets

58

include the through holes

32

and the air release portions

33

provided in the same numbers and having the same shapes, positions, and functions as those of the upper-layer spacer sheet

57

. Incidentally, these members will be denoted by the same reference numerals as those of the upper-layer spacer sheet

57

It should be noted that the diameter of each through hole

32

in each lower-layer spacer sheet

58

is formed to be greater than or equal to the diameter of each through hole

32

in the upper-layer spacer sheet

57

. It goes without saying that if the diameter of each through hole

32

in each spacer sheet

58

becomes large, the space concerning the venting of air can be made large, and the feeling of a click at the time of the switching operation improves.

The aforementioned FPC

54

is a circuit member including a plurality of circuits

35

routed in desired patterns, and the two air vents

36

communicating with the air release portions

33

in the respective layers of the spacer sheet

53

are formed in its central portion. The plurality of contacts

37

are disposed on the spacer sheet

53

side of the FPC

54

. The plurality of chip components

38

are mounted on the adhesive sheet

55

side (the side opposite to the contact

37

side) of the FPC

54

. Incidentally, the circuit member is not confined to the FPC (FPC

54

).

The adhesive sheet

55

is formed so as to be able to bond and fix the FPC

54

. The adhesive sheet

55

is formed so as to be bonded and fixed to the plate

56

. Namely, the adhesive sheet

55

has on one side a circuit attaching surface for the FPC

54

and on its other side a bonding and fixing surface for the plate

56

. The adhesive sheet

55

functions as a reinforcing member. The two air vents

39

communicating with the air vents

36

in the FPC

54

and similar thereto, as well as an accommodating portion

59

(corresponding to the adhesive sheet-side accommodating portion stated in the claims) constituting the aforementioned chip-component accommodating structure, are formed in the adhesive sheet

55

.

The plate

56

includes an attaching surface

60

to which the bonding and fixing surface of the adhesive sheet

55

adheres. The two space portions

41

having, for example, U-shaped cross sections and a recessed portion

61

constituting the aforementioned chip-component accommodating structure are arranged and formed in the attaching surface

60

. The recessed portion

61

is formed in correspondence with the mounting position of the chip components

38

. The recessed portion

61

is formed so as to be able to accommodate the tips of the chip portions

38

. It should be noted that the plate

56

in terms of its shape may be formed in the shape of a housing like a switch casing.

In the above-described construction, the poly-dome switch

51

is assembled as follows: First, the upper-layer spacer sheet

57

and the lower-layer spacer sheets

58

are bonded and fixed together to form the spacer sheet

53

. Next, the surface sheet

52

is bonded and fixed to the surface (actually, the upper-layer-spacer sheet

57

) of the spacer sheet

53

, and the FPC

54

is bonded and fixed to the revere surface (actually, the lowermost lower-layer spacer sheet

58

) of the spacer sheet

53

. Subsequently, the FPC

54

side of this subassembly is bonded and fixed to the circuit attaching surface of the adhesive sheet

55

, so that the plurality of chip components

38

mounted on the adhesive sheet

55

side (the side opposite to the contact

37

side) of the FPC

54

are accommodated in the accommodating portion

59

of the adhesive sheet

55

and the recessed portion

61

of the plate

56

(see FIG.

4

), thereby completing the assembly. It should be noted that the assembled poly-dome switch

51

is mounted by causing the bonding and fixing surface of the adhesive sheet

55

to adhere to the attaching surface

60

of the plate

56

.

As described above, the poly-dome switch

51

in accordance with the second embodiment has the chip-component accommodating structure which allows the plurality of chip components

38

mounted on the adhesive sheet

55

side (the side opposite to the contact

37

side) of the FPC

54

to be accommodated in the accommodating portion

59

of the adhesive sheet

55

and the recessed portion

61

of the plate

56

. Consequently, even if the chip components

38

are mounted on the FPC

54

, the adhesive sheet

55

is prevented from becoming lifted off the FPC

54

and deformed. Accordingly, even if the chip components

38

are mounted on the FPC

54

, the switching function is not affected.

Third Embodiment

Next, referring to

FIG. 5

, a description will be given of the chip-component accommodating structure in a dome switch in accordance with a third embodiment.

FIG. 5

is an exploded cross-sectional view illustrating the third embodiment of the chip-component accommodating structure in a dome switch. It should be noted that portions which are basically identical to the portions of the above-described component members will be denoted by the same reference numerals, and a description thereof will be omitted.

In

FIG. 3

, a poly-dome switch

65

(corresponding to the dome switch stated in the claims) is constituted by the surface sheet

22

having the embossed portion

28

, the spacer sheet

23

(consisting of the upper-layer spacer sheet

30

and the lower-layer spacer sheets

31

) having the accommodating portions

34

, an FPC

66

serving as a circuit member with the chip components mounted on both sides, and the adhesive sheet

55

having the accommodating portion

59

. The poly-dome switch

65

is fixed to the plate

56

having a recessed portion

61

by the adhesive sheet

55

. In the third embodiment of the invention, the chip-component accommodating structure is formed in the surface sheet

22

, the spacer sheet

23

, the adhesive sheet

55

, and the plate

56

. It should be noted that the circuit member is not limited to the FPC (FPC

66

).

As described above, the poly-dome switch

65

in accordance with the third embodiment has the chip-component accommodating structure which allows the plurality of chip components

38

mounted on the spacer sheet

23

side of the FPC

66

to be accommodated in the accommodating portions

34

of the upper-layer spacer sheet

30

and the lower-layer spacer sheets

31

and the embossed portion

28

of the surface sheet

22

. The poly-dome switch

65

in accordance with the third embodiment has the chip-component accommodating structure which allows the chip components

38

mounted on the adhesive sheet

55

side of the FPC

66

to be accommodated in the accommodating portion

59

of the adhesive sheet

55

and the recessed portion

61

of the plate

56

. Consequently, even if the chip components

38

are mounted on the FPC

66

, the spacer sheet

23

is prevented from becoming lifted off the FPC

66

and deformed. Furthermore, even if the chip components

38

are mounted on the FPC

66

, the adhesive sheet

55

is prevented from becoming lifted off the FPC

66

and deformed. Accordingly, even if the chip components

38

are mounted on the FPC

66

, the switching function is not affected.

Next, referring to

FIG. 8

, a description will be given of a specific example of mounting the dome switch.

FIG. 8

is an exploded perspective view illustrating the specific example of mounting the dome switch.

In

FIG. 8

, reference numeral

71

denotes a switch unit for a vehicle Such as an automobile having a plurality of knob switches and a poly-dome switch. The switch unit

71

includes a bezel

73

having a plurality of switch knobs

72

, a rubber contact

74

, an FPC

76

serving as a circuit member having a plurality of contacts

75

, a surface sheet

78

having dome-shaped protuberances

77

, a spacer sheet

79

for adhering to the surface sheet

78

, and an undercasing

80

which is engaged by the bezel

73

. It should be noted that, in the above-described switch unit

71

, a poly-dome switch

81

(corresponding to the dome switch in the claims) is made up by the surface sheet

78

, the spacer sheet

79

, and a portion of the FPC

76

. (It is assumed that the poly-dome switch

81

has the aforementioned chip-component accommodating structure. The component designated; by reference numeral

82

corresponds to the chip component. The undercasing

80

corresponds to the attaching member stated in the claims.) Although the poly-dome switch

81

take up some switches of the switch unit

71

, it goes without saying that the entire unit may be formed by a poly-dome switch such as the aforementioned poly-dome switch

81

.

In addition, it goes without saying that in the invention various modifications are possible within the scope which does not depart from the gist of the invention. Namely, although in the first and third embodiments the embossed portion

28

is formed in the surface sheet

22

, it goes without saying that the embossed portion

28

may be omitted in a case where the height of the chip components

38

is low. In addition, although in the second and third embodiments the recessed portion

61

is formed in the plate

56

, it goes without saying that the recessed portion

61

may be omitted in a case where the height of the chip components

38

is low.

It should be understood that the poly-dome switch (dome switch) is applicable not only to the above-described switch unit for a vehicle such as an automobile or switches of equipment mounted in a vehicle. Namely, the present invention is naturally also applicable to switches for use in household electric products, switches of manufacturing apparatuses, and so forth. In addition, the numbers of the protuberances and the chip components are not limited to the above-mentioned numbers.

Fourth Embodiment

FIG. 6

is an exploded perspective view illustrating a first embodiment of a dome switch in accordance with the invention.

FIG. 7

is an enlarged cross-sectional view of an LED mounting portion shown in FIG.

6

.

In

FIG. 6

, a poly-dome switch

221

(corresponding to the dome switch in the claims) is constituted by a surface sheet

222

, a spacer sheet

223

, a flexible printed circuit (FPC)

224

, and an adhesive sheet

225

. The poly-dome switch

221

is fixed to a plate

226

serving as an example of an attaching member to be attached to by the adhesive sheet

225

. In the first embodiment of the invention, the chip-component accommodating structure is formed in the surface sheet

222

and the spacer sheet

223

.

The surface sheet

222

has a plurality of protuberances

227

and a light emitting portion

128

which is illuminated by the light from a light emitting diode (LED)

239

which will be described later and where the light passes. Each protuberance

227

is formed in a dome shape in which it projects toward the outer surface side and is capable of being reversed toward the inner surface side. An electrode

229

(see

FIG. 7

) for the FPC

224

is provided on the inner surface of each protuberance

227

. The electrode

229

is provided on a top portion of the inner surface. The light emitting portion

228

is formed in correspondence with the mounting position of the LED

239

which will be described later.

The surface sheet

222

will be described in detail. The surface sheet

222

is a synthetic resin-made sheet formed of polyethylene terephthalate (PET), for example, and includes the plurality of dome-shaped protuberances

227

formed by being subjected to heat pressing (by applying pressure from the inner surface side toward the outer surface side). The electrodes

229

provided on top portions of the inner surfaces of the protuberances

227

are formed of carbon or the like (the electrodes

229

formed of carbon are provided by printing).

The spacer sheet

223

is constituted by an upper-layer spacer sheet

230

and two lower-layer spacer sheets

231

. Namely, the spacer sheet

223

is constituted by three layers (the spacer sheet

223

need not necessarily be formed in three layers, and may be formed in a single layer, two layers, or four or more layers; if the spacer sheet

223

is formed in a plurality of layers, there is an advantage that the spacer sheet can be provided with more flexibility than in the case of a single layer). The spacer sheet

223

is adapted to function as a member for preventing the deformation of the surface sheet

222

.

The upper-layer spacer sheet

230

is a synthetic resin-made sheet formed of polyethylene terephthalate (PET), for example, and the upper-layer spacer sheet

230

is formed to be thinner than the lower-layer spacer sheets

231

. Namely, the upper-layer spacer sheet

230

functions as a fine-adjustment sheet member for adjusting the thickness of the spacer sheet

223

. In addition, the upper-layer spacer sheet

230

has layers of an unillustrated adhesive agent on its obverse and reverse surfaces, so that the surface sheet

222

and the lower-layer spacer sheet

231

can be fixed to its obverse and reverse surfaces, respectively.

The upper-layer spacer sheet

230

will be described in detail. The upper-layer spacer sheet

230

includes a plurality of through holes

232

, a plurality of air release portions

233

, and the light diffusing member

234

for diffusing the light emitted from the LED

239

(described later). Each of the through holes

232

is a portion for ensuring contact between the electrode

229

of the protuberance

227

and a contact

237

(which will be described later) of the FPC

224

, and is formed in conformity with the position of the corresponding protuberance

227

. Each of the through holes

232

is formed to have a diameter greater than or equal to the diameter of the protuberance

227

(see FIG.

7

).

Each of the air release portions

233

is a portion which allows the air located on the inner surface side to be released appropriately when each protuberance

227

is reversed. The air release portions

233

are formed between adjacent ones of the through holes

232

arranged in the longitudinal direction in the upper-layer spacer sheet

230

. Each of the air release portions

233

is formed in the shape of a slit in such a manner as to communicate with the corresponding through holes

232

.

The light diffusing member

234

is formed in a rectangular shape in correspondence with the mounting position of the LED

239

which will be described later. The light diffusing member

234

is formed in such a manner as to continue to the light emitting portion

228

of the surface sheet

222

. The light diffusing member

234

is formed by effecting printing in a white color, for example. Incidentally, the formation of the light diffusing member

234

is arbitrary. In a case where the light diffusing member

234

is not formed, it suffices if a portion identical to a light guiding portion

235

which will be described later is formed.

Each of the lower-layer spacer sheets

231

is a synthetic resin-made sheet formed of polyethylene terephthalate (PET), for example, and includes unillustrated adhesive layers on its obverse and reverse surfaces, so that after their lamination the upper-layer spacer sheet

230

and the FPC

224

can be fixed to the obverse and reverse surfaces, respectively. The lower-layer spacer sheets

231

includes the through holes

232

and the air release portions

233

provided in the same numbers and having the same shapes, positions and function as those of the upper-layer spacer sheet

230

, and a light guiding portions

235

formed in accordance with the mounting position of the LED

239

described later Incidentally, these members will be denoted by the same reference numerals as those of the upper-layer spacer sheet

230

, and a description thereof will be omitted It should be noted that the diameter of each through hole

232

in each lower-layer spacer sheet

231

is formed to be greater than or equal to the diameter of each through hole

232

in the upper-layer spacer sheet

230

. It goes without saying that if the diameter of each through hole

232

in each spacer sheet

231

becomes large, the space concerning the venting of air can be made large, and the feeling of a click at the time of the switching operation improves.

The light guiding portions

235

in the respective layers are formed so as to be able to accommodate the LED

239

(which will be described later) at the time of assembly, and so as to be able to guide the light from the LED

239

to the light emitting portion

228

of the surface sheet

222

(or the light diffusing member

234

) after the assembly. In addition, the light guiding portions

235

are formed in the shape of through holes of a rectangular shape (however, their shape is not limited to the same).

The FPC

224

(corresponding to the circuit member in the claims) comprises a circuit member body

243

including a plurality of circuits

236

routed in desired patterns and an external connection member

244

used for electrical connection to external circuits.

The plurality of contacts

238

with which the electrodes

229

(see

FIG. 7

) are brought into contact are disposed on the spacer sheet

223

side of the circuit member body

243

. In addition, two air vents

237

communicating with the air release portions

233

in the respective layers of the spacer sheet

223

are formed in the center of the circuit member body

243

. The LED

239

is mounted on the spacer sheet

223

side (contact

238

side of the FPC

224

) of the circuit member body

243

. Incidentally, the circuit member is not confined to the FPC (FPC

224

).

The external connection member

244

comprises a connection circuit portion

245

formed so as to be led out from the circuit member body

243

, and a plurality of edge connector terminals

246

provided at a tip portion of the connection circuit portion

245

. The connection circuit portion

245

has an appropriate length, and the circuits

236

led out from the circuit member body

243

are routed in it. In addition, the circuits

236

led out from the circuit member body

243

are respectively connected to the corresponding edge connector terminals

246

.

The adhesive sheet

225

is formed so as to be able to bond and fix the FPC

224

. The adhesive sheet

225

is formed so as to be bonded and fixed to the plate

226

. Namely, the adhesive sheet

225

includes on one side a circuit attaching surface for the FPC

224

and on its other side a bonding and fixing surface for the plate

226

. The adhesive sheet

225

functions as a reinforcing member. Two air vents

240

communicating with the air vents

237

in the FPC

224

and similar thereto are formed in the adhesive sheet

225

.

The plate

226

includes an attaching surface

241

to which the bonding and fixing surface of the adhesive sheet

225

adheres. Two space portions

242

having, for example, U-shaped cross sections are arranged and formed in the attaching surface

241

. The space portions

242

are communicated with the air release portions

233

in the spacer sheet

223

through the air vents

237

in the FPC

224

and the air vents

240

in the adhesive sheet

225

(the air vents

237

in the FPC

224

and the air vents

240

in the adhesive sheet

225

function as passages for communication with the air release portions

233

in the spacer sheet

223

and the space portions

242

in the plate

226

). It should be noted that the plate

226

in terms of its shape may be formed in the shape of a housing like a switch casing.

In the above-described construction, the poly-dome switch

221

is assembled as follows: First, the upper-layer spacer sheet

230

and the lower-layer spacer sheets

231

are bonded and fixed together to form the spacer sheet

223

. Next, the surface sheet

222

is bonded and fixed to the surface (actually, the upper-layer spacer sheet

230

) of the spacer sheet

223

, and the FPC

224

is bonded and fixed to the revere surface (actually, the lowermost lower-layer spacer sheet

231

) of the spacer sheet

223

, so that the LED

239

mounted on the spacer sheet

223

side (contact

238

side) of the FPC

224

are accommodated in the light guiding portion

235

of the lower-layer spacer sheets

231

(see FIG.

7

). Subsequently, the FPC

224

side of this subassembly is bonded and fixed to the circuit attaching surface of the adhesive sheet

225

, thereby completing the assembly. It should be noted that the assembled poly-dome switch

221

is mounted by causing the bonding and fixing surface of the adhesive sheet

225

to adhere to the attaching surface

241

of the plate

226

and connecting the external connection member

244

to a predetermined connection portion.

As described above, in the poly-dome switch

221

, the LED

239

is mounted on the FPC

224

in accordance with the invention. When the mounted LED

239

is made to emit light, the light from the LED

239

is guided through the light guiding portions

235

in the spacer sheet

223

, and the light emitting portion

228

of the surface sheet

222

is illuminated. The light emitting portion

228

itself, as it were, emits light due to the light which passed through the light emitting portion

228

. When the mounted LED

239

is made to emit light, the light from the LED

239

is diffused by the light diffusing member

234

. The entire light emitting portion

228

of the surface sheet

222

is then illuminated by the diffused light. Meanwhile, in the assembly of the poly-dome switch

221

, the LED

239

mounted on the FPC

224

is accommodated in the light guiding portions

235

of the spacer sheet

223

. In other words, by forming the light guiding portions

235

in the spacer sheet

223

, it becomes possible to mount the LED

239

on the contact

238

side of the FPC

224

. Accordingly, it becomes possible to provide the poly-dome switch

221

capable of illuminating the switch.

In the invention, since the adhesive sheet

225

is provided, and the FPC

224

is provided with the external connection member

244

, the poly-dome switch

221

can be easily installed at a position which meets the user's need. In the invention, since electrical connection to external circuits can be established through the edge connector terminals

246

(the same also applies to a connector

247

which will be described later), the installation of the poly-dome switch

221

is facilitated, and the range of its installation can be expanded. In the invention, since connection to external circuits can be made within the range of the length of the connection circuit portion

245

, the range of installation of the poly-dome switch

221

can be further expanded.

It should be noted that although the mounting of the LED

239

makes the spacer sheet

223

thick in correspondence with the height of the LED

239

, there is an advantage in that the dimension of the stroke of the protuberance

227

can be enlarged (a large stroke can be obtained for the protuberance

227

).

Next, referring to

FIG. 9

, a description will be given of a specific example of mounting the dome switch.

FIG. 9

is an exploded perspective view illustrating the specific example of mounting the dome switch.

In

FIG. 9

, reference numeral

271

denotes a switch unit for a vehicle such as an automobile having a plurality of knob switches and a poly-dome switch. The switch unit

271

includes a bezel

273

having a plurality of switch knobs

272

, a rubber contact

274

, an FPC

276

serving as a circuit member having a plurality of contacts

275

, a surface sheet

278

having dome-shaped protuberances

277

, a spacer sheet

279

for adhering to the surface sheet

278

, and an undercasing

180

which is engaged by the bezel

273

. It should be noted that, in the above-described switch unit

271

, a poly-dome switch

281

(corresponding to the dome switch stated in the claims) is made up by the surface sheet

276

, the spacer sheet

279

, and a portion of the FPC

276

. (It is assumed that the poly-dome switch

281

has the aforementioned chip-component accommodating structure. The component designated by reference numeral

282

corresponds to the LED. The component designated by reference numeral

283

is the light emitting portion. The undercasing

280

corresponds to the attaching member stated in the claims.) Although the poly-dome switch

281

take up some switches of the switch unit

271

, it goes without saying that the entire unit may be formed by a poly-dome switch such as the aforementioned poly-dome switch

281

.

Fifth Embodiment

Next, referring to

FIGS. 10

to

12

, a description will be given of a second embodiment of the dome switch.

FIG. 10

is an exploded perspective view illustrating the second embodiment of the dome switch in accordance with the invention. Further,

FIG. 11

is an enlarged plan view of the spacer sheet shown in

FIG. 10

, and

FIG. 12

is an enlarged cross-sectional view of an LED mounted portion shown in FIG.

11

.

In

FIG. 10

, a poly-dome switch

121

of the invention (corresponding to the dome switch in the claims) comprises a surface sheet

122

, a spacer sheet

123

, and a flexible printed circuit (FPC)

124

. The poly-dome switch

121

comprises an adhesive sheet

125

required at the time of installation. In the poly-dome switch

121

of the invention having such construction, an LED

138

which will be described later is mounted on the FPC

124

in the same way as the above-described poly-dome switch

221

(see FIG.

6

).

The surface sheet

122

is flexible, and is provided with a plurality of protuberances

127

and a plurality of second light emitting portions

128

which are illuminated by the light from the LEDs

138

which will be described later and where the light passes. Each of the protuberances

127

is formed in a dome shape so as to project toward outside and is capable of being reversed toward inside. An electrode

129

(see

FIG. 12

) for the FPC

124

is provided on the inner surface of each protuberance

127

. The electrode

129

is provided on a top portion of the inner surface.

The surface sheet

122

will be described in detail. The surface sheet

122

is a synthetic resin-made sheet member formed of polyethylene terephthalate (PET), for example, and includes the protuberances

127

formed by being subjected to heat pressing (by applying pressure from the inner surface side toward the outer surface side). The electrodes

129

(see

FIG. 12

) provided on top portions of the inner surfaces of the protuberances

127

are formed of carbon or the like (the electrodes

129

formed of carbon are provided by printing).

Since the surface sheet

122

is formed of the aforementioned material, the surface sheet

122

is originally transparent, and in this embodiment symbols including a triangle “Δ,” a square “□,” and an inverse triangle “∇” are printed on its inner surface in, for instance, a solid black color (printed so as to correspond to the respective protuberances

127

). A background color is also printed in, for instance, a white color on that inner surface (the electrodes

129

formed of carbon are provided after the printing). It should be noted that in this embodiment the aforementioned background color functions as the reflector in the claims. Incidentally, as a color other than the white color, it is possible to cite a silver color. The reflector suffices insofar as it is capable of reflecting the light and preventing the light from leaking from the spacer sheet

123

. Apart from the above-described technique, it is possible to cite a technique in which after the printing of the background color in an appropriate manner, a reflector is provided. The reflector has the advantage of being able to guide the light efficiently.

In this embodiment, the second light emitting portions

128

are portions which are not provided with the aforementioned background color and reflector, and portions coinciding with the respective protuberances

127

and portions surrounding the aforementioned symbols correspond to the second light emitting portions

128

.

In

FIGS. 10 and 11

, the spacer sheet

123

is a synthetic resin-made flexible transparent sheet member formed of, for example, polyethylene terephthalate (PET), and functions as a member for preventing the deformation of the surface sheet

122

. The spacer sheet

123

has layers of an unillustrated adhesive agent on its obverse and reverse surfaces, so that the surface sheet

122

and the FPC

124

can be fixed to its obverse and reverse surfaces, respectively. The spacer sheet

123

includes a plurality of through holes

130

, a plurality of second light guiding portions

131

formed in correspondence with the mounting positions of the LEDs

138

which will be described later, and a plurality of light collecting portions

132

formed in correspondence with the positions of the second light emitting portions

128

.

The through holes

130

are respectively formed in alignment with the positions of the corresponding protuberances

127

, and are.adapted to allow the reversed protuberances

127

to pass therethrough. Each of through holes

130

is formed to have a diameter greater than the diameter of the corresponding protuberance

127

(see FIG.

12

). However, the diameter of each through hole

130

may be identical to that of the protuberance

127

.

Each of the second light guiding portions

131

is formed so as to be able to accommodate the LED

138

(which will be described later) at the time of assembly, and so as to be able to guide the light from the LED

138

(see an optical path

133

) into the spacer sheet

123

after the assembly. The second light guiding portions

131

are formed in the shape of through holes of a rectangular shape (however, their shape is not limited to the same).

In this embodiment, the light collecting portions

132

are formed as substantially U-shaped slits which, for example, partially surround the through hole

130

(the portion corresponding to one second light emitting portion

12

B) and a portion

134

corresponding to the symbol (the portion corresponding to another second light emitting portion), respectively. The light collecting portions

132

are so arranged that their inner side surfaces

135

are able to reflect the guided light (see the optical path

133

) and collect it to the respective portions mentioned above.

In

FIG. 10

, the FPC

124

(corresponding to the circuit member stated in the claims) includes a plurality of circuits

136

routed in desired patterns. A plurality of contacts

137

which are contacted by the electrodes

129

(see

FIG. 12

) are provided on the spacer sheet

123

side of the FPC

124

. The LEDs

138

are mounted on the spacer sheet

123

side (contact

137

side) of the FPC

124

. The reflector similar to the one described above is provided over a substantially entire surface of the spacer sheet

123

side (contact

137

side) of the FPC

124

.

It should be noted that the circuit member is not limited to the FPC (FPC

124

). The above-described external connection member

44

(see

FIG. 6

) may be provided. The reflector may be provided not only on the surface sheet

122

and the FPC

124

but also on the obverse and reverse surfaces of the spacer sheet

123

.

The adhesive sheet

125

is formed so as to allow the FPC

124

to be bonded and fixed thereto. Namely, the adhesive sheet

125

has on one side a circuit attaching surface with respect to the FPC

124

. Meanwhile, the adhesive sheet

125

has on its other side a bonding and fixing surface with respect to, for instance, the plate

226

(see

FIG. 6

) serving as an attaching member. Unillustrated release paper is provided on the bonding and fixing surface of the adhesive sheet

125

. The unillustrated release paper is provided to protect the bonding and fixing surface up until the time of final use and to permit the carrying of the poly-dome switch

121

.

It should be noted that the adhesive sheet

125

may function as a reinforcing member within the range which does not impair the flexibility of the poly-dome switch

121

. The release paper may be provided on the adhesive sheet

225

.

In the above-described construction, the poly-dome switch

121

is assembled as follows: First, the surface sheet

122

is bonded and fixed to the surface of the spacer sheet

123

, and the FPC

124

is bonded and fixed to the reverse surface of the spacer sheet

123

, so that the LEDs

138

mounted on the spacer sheet

123

side (contact

137

side) of the FPC

124

are accommodated in the second light guiding portions

131

of the spacer sheet

123

(see FIG.

6

). Next, the FPC

124

side of this subassembly is bonded and fixed to the circuit attaching surface of the adhesive sheet

125

, thereby completing the assembly.

It should be noted that the assembled poly-dome switch

121

is mounted by causing the bonding and fixing surface of the adhesive sheet

125

to adhere to the attaching surface

241

(see

FIG. 6

) of the plate

226

, for example (alternatively, the assembled poly-dome switch

121

may be applied to the above-described switch unit

271

instead of the dome switch

81

(see FIG.

9

)).

As described above, in the poly-dome switch

121

, the LEDs

138

are mounted on the FPC

124

in accordance with the second embodiment of the invention. When the mounted LEDs

138

are made to emit light, as shown in

FIG. 12

(a design portion

139

is provided as an example on the outer side of the second light emitting portion

128

), the light (see the optical path

133

) from the LEDs

138

is guided through the second light guiding portions

131

and the light collecting portions

132

in the spacer sheet

123

, and the second light emitting portions

128

of the surface sheet

122

are illuminated. The light emitting portions

128

themselves, as it were, emit light due to the light which passed through the second light emitting portions

128

. Meanwhile, in the assembly of the poly-dome switch

121

, the LEDs

138

mounted on the FPC

124

are accommodated in the second light guiding portions

131

of the spacer sheet

123

. In other words, by forming the second light guiding portions

131

in the spacer sheet

123

, it becomes possible to mount the LEDs

138

on the contact

137

side of the FPC

124

. Accordingly, it becomes possible to provide the poly-dome switch

121

capable of illuminating the switch.

Modification

Next, a description will be given of a modification based on the above-described poly-dome switch

221

in the fourth embodiment (the same also applies to the poly-dome switches

281

and

121

in the case where the external connection member

244

is provided).

FIG. 13

is a perspective view for explaining another example of the external connection member

244

. In addition,

FIG. 14

is a cross-sectional view for explaining still another example of the external connection member

244

.

In

FIG. 13

, the plurality of edge connector terminals

246

are provided in the external connection member

244

(see FIG.

6

), but an arrangement is provided such that, instead of the plurality of edge connector terminals

246

, a connector

247

indicated by the phantom lines can be provided at the tip portion of the connection circuit portion

45

, as shown in FIG.

13

. Thus, it should be understood that the arrangement of the external connection member

244

can be modified, as required, in conformity with the form of the mating member for connection.

The external connection member

244

(see

FIG. 6

) is provided with the connection circuit portion

245

having an appropriate length, but the external connection member

244

may be constituted by only the plurality of edge connector terminals

246

, as shown in FIG.

14

. The plurality of edge connector terminals

246

may be provided in such a manner as to be bent perpendicularly to the circuit member body

243

or provided in such a manner as to be bent to extend along the bonding and fixing surface of the adhesive sheet

225

. Therefore, it should be understood that the arrangement of the external connection member

244

can be modified, as required, in conformity with the mating member for connection.

It goes without saying that in the invention various modifications are possible within the scope which does not depart from the gist of the invention. Namely, the numbers of the protuberances and the LEDs are not limited to the above-mentioned numbers.

It should be understood that the poly-dome switch (dome switch) is applicable not only to the above-described switch unit for a vehicle such as an automobile or switches of equipment mounted in a vehicle. Namely, the present invention is naturally also applicable to switches for use in household electric products, switches of manufacturing apparatuses, and so forth.

As described above, in accordance with the invention, since the spacer sheet-side accommodating portion is formed in the spacer sheet, in the assembly of the dome switch, the chip component mounted on the contact side of the circuit member can be accommodated in the spacer sheet-side accommodating portion. Accordingly, it becomes possible to provide a chip-component accommodating structure in a dome switch which makes it possible to mount a chip component on a circuit member.

In accordance with the invention, since the adhesive sheet-side accommodating portion is formed in the adhesive sheet, in the assembly of the dome switch, the chip component mounted on the side of the circuit member opposite to the side where the contact is formed can be accommodated in the adhesive sheet-side accommodating portion. Accordingly, it becomes possible to provide a chip-component accommodating structure in a dome switch which makes it possible to mount a chip component on a circuit member.

In accordance with the invention, since the spacer sheet-side accommodating portion is formed in the spacer sheet, in the assembly of the dome switch, the chip component mounted on the contact side of the circuit member can be accommodated in the spacer sheet-side accommodating portion. In addition, since the adhesive sheet-side accommodating portion is formed in the adhesive sheet, in the assembly of the dome switch, the chip component mounted on the side of the circuit member opposite to the side where the contact is formed can be accommodated in the adhesive sheet-side accommodating portion. Accordingly, it becomes possible to provide a chip-component accommodating structure in a dome switch which makes it possible to mount a chip component on a circuit member

In accordance with the invention, since the embossed portion is formed in the surface sheet, it becomes possible to mount the chip component with large height on the contact side of the circuit member.

In accordance with the invention, since the recessed portion is formed in the attaching member, it becomes possible to mount the chip component with large height on the side of the circuit member opposite to the side where the contact is disposed.

Further in accordance with the invention, since the light guiding portion for accommodation and light guidance for the LED is formed in the spacer sheet, the LED can be mounted on the circuit member. In addition, if the LED is made to emit light, the light guided by the light guiding portion of the spacer sheet illuminates the light emitting portion of the surface sheet, so that the light emitting portion itself is made to appear to, as it were, emit the light due to the light which passed through the light emitting portion. Accordingly, an advantage is offered in that it is possible to provide a dome switch capable of illuminating the switch.

In accordance with the invention, since the diffusing means is formed in the light guiding portion of the spacer sheet, it is possible to guide the diffused light toward the light emitting portion of the surface sheet. Accordingly, an advantage is offered in that the overall portion to be illuminated can be reliably illuminated.

In accordance with the invention, since the second light guiding portion for accommodation and light guidance for the LED is formed in the spacer sheet, the LED can be mounted on the circuit member. In addition, if the LED is made to emit light, the light guided by the second light guiding portion and the light guiding portion of the spacer sheet illuminates the second light emitting portion of the surface sheet, so that the second light emitting portion itself is made to appear to, as it were, emit the light due to the light which passed through the second light emitting portion. Accordingly, an advantage is offered in that it is possible to provide a dome switch capable of illuminating the switch.

In accordance with the invention, the light can be efficiently guided between the second light guiding portion and the light collecting portion by the reflector. Accordingly, an advantage is offered in that the second light emitting portion can be made to emit light sufficiently.

In accordance with the invention, since the adhesive sheet is further provided in the arrangement, and since the circuit member has the external connection member, an advantage is offered in that the dome switch can be installed at a position which meets the user's need (the range of installation can be further expanded). In addition, there is another advantage in that the dome switch can be easily attached (the installation can be facilitated).

In accordance with the invention, electrical connection to an external circuit can be effected by the edge connector terminals or the connector. Accordingly, in addition to the advantages of the invention according to claim 5, an advantage is offered in that the installation is further facilitated.

In accordance with the invention, electrical connection to an external circuit can be made within the range of the length of the connection circuit portion led out from the circuit member body. Accordingly, in addition to the advantages of the invention according to claim 6, an advantage is offered in that the range of installation can be further expanded.

In accordance with the invention, an advantage is offered in that the protection of the bonding and fixing surface and the carrying of the switch are made possible.

Number	Name	Date	Kind
4598181	Selby	Jul 1986	A
4916275	Almond	Apr 1990	A
5828016	Grannan et al.	Oct 1998	A
6073341	Odorfer	Jun 2000	A
6084189	Menche et al.	Jul 2000	A

Dome switch

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

US Referenced Citations (5)