United States Patent [191
`Liao
`
`US005743386A
`[11] Patent Number:
`{45] Date of Patent:
`
`5,743,386
`Apr. 28, 1998
`
`[54] MEMBRANE SWITCH ASSEMBLY
`
`[75] Inventor: Pin-Chien Liao. Taoyuan, Taiwan
`
`4,700,025 lO/l987 Hatayama et a1. .................... .. 200/512
`5.149.923
`9/1992 Demeo .................................. .. 200/512
`
`[73] Assignee: Acer Peripherals, Inc. Taiwan
`
`Primary Examiner-David J. Walczak
`
`[21] Appl. No.: 682,491
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`[22] Filed;
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`Jul, 17, 1996
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`6
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`[2;]
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`[56]
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`References Cited
`NTS
`S PATENT DOC
`U. .
`UME
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`[57]
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`ABSTRACT
`
`A membrane switch including a rubber dome. an insulation
`layer. a membrane and an electric-conductive support plate
`is provided. The membrane switch is ON as the pair of
`non-contacting circuit leads is forced to contact with the
`support plate due to the force applied on the rubber dome.
`As the rubber dome is free of an external force. the pair of
`non-cpntacting circuit leads is spaced from the support plate.
`resulting 1n an OFF state of the membrane SWl'tCl‘L
`
`200 ’
`513551124 551165‘
`’
`‘
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`4,684,767
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`8/1987 Phalen ................................... .. 200/512
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`8 Claims, 3 Drawing Sheets
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`2 2 l C
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`26 / / wy/r/
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`22 IA
`22/A ' 221A
`2218
`22
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`2 2
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`22 I C
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`26
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`1 23
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`22/5’
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`Apple Inc., et al.
`Exhibit 1015
`Apple Inc., et al. v. Global Touch Solutions, Inc.
`IPR2015-01173
`
`Exhibit 1015, Page 001
`
`

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`U.S. Patent
`
`Apr. 23, 1993
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`Sheet 1 of 3
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`5,743,386
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`/A
`F/G.
`PR/OR A R T
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`/2/B
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`12/
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`/2/A
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`I218
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`/B
`F/G.
`PRIOR ART
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`12/
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`Exhibit 1015, Page 002
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`
`

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`US. Patent
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`Apr. 28, 1998
`
`Sheet 2 of 3
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`5,743,386
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`F / G. 2A
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`2/
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`2 2
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`26
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`// g
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`26
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`$23
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`ax?
`/ w ml
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`22/ SK
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`7//////
`//////
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`M221
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`22 IA
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`r2218
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`//////// /
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`F/G. 2B
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`Exhibit 1015, Page 003
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`

`
`US. Patent
`
`Apr. 28, 1998
`
`Sheet 3 0f 3
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`5,743,386
`
`F/G. 3
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`Exhibit 1015, Page 004
`
`

`
`5,743,386
`
`1
`MEMBRANE SWITCH ASSEMBLY
`
`TECHNICAL FIELD OF INVENTION
`
`The invention relates to a membrane switch formed on a
`single membrane mylar.
`
`BACKGROUND OF INVENTION
`
`The membrane switch has been widely used in the input
`device of electrical instruments. e.g.. keyboard of portable
`personal computer. One conventional membrane switch. as
`shown in FIG. 1. includes a rubber dome 11. a support plate
`13. a membrane mylar 12. a conductive-pad 111 and a circuit
`pattern 121 with a pair of non-contacting circuit leads 121A
`and 121B printed on the membrane mylar 12. As an external
`force is applied on the rubber dome 11 causing its downward
`deformation. the conductive-pad 111 contacts with the pair
`of non-contacting circuit leads 121A and 121B thereby
`turning ON the membrane switch. Mylar is the commercial
`name of the polymer material used as the membrane 12 and
`that is well known to persons skilled in arts.
`Two major drawbacks have been observed with regard to
`the prior art of FIG. 1. First of all. the electric conductivity
`of the conductive-pad 111 may gradually attenuate due to
`numbers of operation. oxidation effect. sulfuration effect of
`the conductive-pad 111 or environment e?ects. etc.
`Secondly. a layer of the conductive-pad 111 must be pro
`vided on the corresponding inner surface of the rubber dome
`11 that is an extra process and costs more.
`To resolve the drawbacks and higher cost mentioned
`above. the function. of the membrane switch is achieved by
`the instant invention without additional process.
`
`25
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`30
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`SUMMARY OF INVENTION
`
`35
`
`A membrane switch assembly comprises an electric
`conductive support plate. a membrane and a rubber dome.
`The membrane has a bottom surface printed with a circuit
`pattern. The rubber dome is disposed on the membrane to
`actuate the membrane switch assembly. The membrane
`switch is ON as the pair of non-contacting circuit leads is
`forced to contact with the support plate due to the force
`applied on the rubber dome. As the rubber dome is free of
`an external force. the pair of non-contacting circuit leads is
`spaced from the support plate.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1(A) illustrates the sectional view of a conventional
`membrane switch. FIG. 1(B) illustrates the plane view of the
`pair of non-contacting circuit leads 121A. 121B and circuit
`pattern 121.
`FIG. 2(A) illustrates one embodiment of the invention in
`sectional view.
`FIG. 2(B) illustrates the plane view of the pair of non
`contacting circuit leads 221A. 221B and circuit pattern 221
`of FIG. 2(A).
`FIG. 3 illustrates another embodiment of the invention in
`sectional view.
`
`55
`
`DETAILED DESCRIPTIONS OF THE
`PREFERRED ENIBODIMENT
`As shown in FIG. 2. the membrane switch of the instant
`invention comprises a rubber dome 21. an electric
`conductive support plate 23. a membrane mylar 22. a bottom
`conductive circuit pattern 221. which includes portions
`221A. 221B and 221C shown. printed on the bottom of
`
`65
`
`2
`membrane mylar 22. The portions 221A. 221B constitute a
`pair of non-contacting circuit leads of the circuit pattern 221.
`In addition. insulator printings 26 is printed over the con
`ductive circuit layer 221C for providing insulation purpose
`and minimum required height of the membrane switch. The
`thickness of the insulation layer 26 depends on the inner
`diameter of rubber dome 21 and the bounce speed of the
`switch. Typically. the thickness of insulation layer 26 varies
`from 0.04 mm to 0.110 mm. The top view of the circuit
`pattern 221 may be one shown in FIG. 2(B). The membrane
`switch is ON as the pair of circuit leads 221A. 221B are
`forced to contact the electric-conductive support plate 23
`due to the force applied on the rubber dome 21. As the
`rubber dome 21 is freed of an external force. the pair of
`circuit lead 221A. 221B become spaced from the support
`plate 23 resulting in an OFF state of the membrane switch.
`As shown in FIG. 3. the other embodiment of the instant
`invention comprises a rubber dome 21. an electric
`conductive support plate 23. a membrane mylar 22. a bottom
`conductive circuit pattern 221. which includes portions
`221A. 221B and 221C shown. printed on the bottom of
`membrane mylar 22. The portions 221A. 221B constitute a
`pair of non-contacting circuit leads of the circuit pattern 221.
`Furthermore. a printing layer 25 is provided over the circuit
`layer 221C to meet the minimum required height of the
`membrane switch. This printing layer 25 may be either
`conductive material or non-conductive material. Over the
`printing layer 25. an insulator printings 26 is thereafter
`printed for providing insulation purpose. The total thickness
`of the insulation layer 26 and layer 25 depends on the inner
`diameter of rubber dome 21 and the bounce speed of the
`switch. Typically. the total thickness of insulation layer 26
`and layer 25 varies from 0.04 mm to 0.110 mm. The top
`view of the circuit pattern 221 may be one shown in FIG.
`2(B). The membrane switch is ON as the pair of circuit leads
`221A. 221B are forced to contact the electric-conductive
`support plate 23 due to the force applied on the rubber dome
`21. As the rubber dome 21 is freed of an external force. the
`pair of circuit leads 221A. 221B are spaced from the support
`plate 23 resulting in an OFF state of the membrane switch.
`As well known in the arts. the circuit pattern is layer of
`conductive material. e.g.. silver. silver/graphite mixture. in
`paste form which are printed on the membrane ?rst and then
`dried under an adequate temperature. It is well known that
`?nger array is formed on predetermined boundary of the
`membrane mylar which acts as interface with other electric
`device. e.g.. connector of the computer‘s system bus. The
`production of ?nger array of the membrane switches assem
`bly usually needs a print process of carbon layer or graphite
`layer and. during the print process. the carbon or graphite
`printings 25 is printed which requiring no additional pro
`cess. To enhance the reliability. in typical. a layer of
`di-electric paint is usually provided on the bottom of the
`membrane mylar 22 to avoid short circuit between the
`printed circuits or between printed circuits and conductive
`support plate 23. except areas encompassing the circuit
`pattern and a pair of non-contacting circuit leads 221A and
`2218. Therefore. the insulator printing 26 is printed during
`the print process of the di-electric paint.
`What is claimed is:
`1. A membrane switch assembly including at least N
`membrane switches. N being a whole number that is 2 or
`greater. comprising:
`a single electric-conductive support plate;
`a membrane having a bottom surface printed with a circuit
`pattern including at least N pairs of non-contacting
`circuit leads. each pair of non-contacting circuit leads
`corresponding to one of said N membrane switches;
`
`Exhibit 1015, Page 005
`
`

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`5.743.386
`
`3
`at least N rubber domes each having an actuator disposed
`on said membrane to actuate one of said corresponding
`membrane switches;
`an insulating layer on a predetermined area of said circuit
`pattern in contact with said single electric-conductive
`support plate:
`wherein each of said membrane switches is ON as its
`corresponding pair of non-contacting circuit leads is
`forced to contact said single electric-conductive sup
`port plate due to an external force applied on said
`corresponding rubber dome. and. as said corresponding
`rubber dome is freed of an external force. said corre
`sponding pair of non-contacting circuit leads becomes
`spaced from said single electric-conductive support
`plate resulting in an OFF state of said corresponding
`membrane switch.
`2. The membrane switch assembly as recited in claim 1.
`wherein said insulating layer is printed on a predetermined
`area of said circuit pattern.
`3. The membrane switch assembly as recited in claim 1.
`wherein said insulating layer is formed from a polymer
`material.
`4. A membrane switch assembly including at least N
`membrane switches. N being a whole number that is 2 or
`greater. comprising:
`a single electric-conductive support plate;
`a membrane having a bottom surface printed with a circuit
`pattern including at least N pairs of non-contacting
`circuit leads. each pair of non-contacting circuit leads
`corresponding to one of said N membrane switches;
`
`15
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`25
`
`4
`at least N rubber domes each having an actuator disposed
`on said membrane to actuate one of said corresponding
`membrane switches;
`a printing layer on a predetermined area of said circuit
`pattern;
`an insulating layer between said printing layer and said
`single electric-conductive support plate;
`wherein each of said membrane switches is ON as its
`corresponding pair of non-contacting circuit leads is
`forced to contact said single electric conductive support
`plate due to an external force applied on said corre
`sponding rubber dome. and. as said corresponding
`rubber dome is freed of an external force. said corre
`sponding pair of non-contacting circuit leads becomes
`spaced from said single electric-conductive support
`plate resulting in an OFF state of said corresponding
`membrane switch.
`5. The membrane switch assembly as recited in claim 4.
`wherein said insulating layer is printed on said printing
`layer.
`6. The membrane switch assembly as recited in claim 4.
`wherein said insulating layer is formed from a polymer
`material.
`7. The membrane switch assembly as recited in claim 4.
`wherein said printing layer is formed from a nonconductive
`material.
`8. The membrane switch assembly as recited in claim 4.
`wherein said printing layer is formed from conductive
`material.
`
`Exhibit 1015, Page 006