CAPACITIVE TOUCH DEVICE

Abstract

A method of assembling a capacitive touch device is disclosed. The method comprises providing a flexible sheet having first and second faces and first and second wings divided by a fold line. The flexible sheet supports capacitive touch switches, contact lands and conductive tracks interconnecting the capacitive touch switches and the contact lands on the first face of the flexible sheet. The method comprises providing adhesive on the first face of the flexible sheet so as to bond the first and second wings and to bond a circuit board to flexible sheet. The method comprises placing a circuit board on the flexible sheet, the circuit board having contact pads which are aligned with the contact lands and folding the flexible sheet along the fold line so as to bond the first and second wings with the circuit board interposed between the first and second wings.

Claims

1. A method of assembling a capacitive touch device, the method comprising: providing a flexible sheet having: first and second faces; and first and second wings divided by a fold line, wherein the flexible sheet supports capacitive touch switches, contact lands and conductive tracks interconnecting the capacitive touch switches and the contact lands on the first face of the flexible sheet; providing adhesive on the first face of the flexible sheet so as to bond the first and second wings and to bond the circuit board to flexible sheet; placing a circuit board on the flexible sheet, the circuit board having contact pads which are aligned with the contact lands; and folding the flexible sheet along the fold line so as to bond the first and second wings with the circuit board interposed between the first and second wings.

2. A method according to claim 1, wherein providing the flexible sheet and providing adhesive comprises providing a flexible sheet having an adhesive layer and a peelable backing layer, wherein the method further comprises: removing at least part of backing layer before folding the flexible sheet.

3. A method according to claim 1, further comprising: passing the flexible sheet folded along the fold line through a press.

4. A method according to claim 1, wherein the flexible sheet further comprises a wing extension extending from the first wing along another fold line, wherein the method further comprises: folding the wing extension onto first wing before completing folding the second wing onto the first wing.

5. A method according to claim 4, wherein the wing extension includes an aperture configured to accommodate the circuit board.

6. A capacitive touch device fabricated using the method according to claim 1.

7. A capacitive touch device comprising: a flexible sheet laminate comprising: a first flexible sheet; and a second flexible sheet; capacitive touch switches, contact lands and conductive tracks interconnecting the capacitive touch switches and the contact lands supported on inward faces of the flexible sheet(s); adhesive on the inward faces of the flexible sheet(s) so as to bond the first and second sheets and to bond a circuit board to flexible sheet(s); a circuit board interposed between the flexible sheets, the circuit board having contact pads which are aligned with the contact lands.

8. A capacitive touch device according to claim 7, wherein the first and second sheets comprise first and second wings of a single sheet divided by a fold line.

9. A capacitive touch device according to claim 7, further comprising: a strip of flexible sheet interposed between the flexible sheets, the flexible strip having an aperture, wherein the circuit board is disposed in the aperture.

10. A capacitive touch device according to claim 7, wherein the circuit board supports a coin cell holder adjacent to the second sheet and wherein the second sheet has a slit arranged to form a flap over the coin cell holder which is configured to allow a coin cell to be re-insertably removed from the coin cell holder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Certain embodiments of the present invention will now be described by way of example, with reference to the accompanying drawings, in which:

[0067] FIG. 1 is a perspective view of an assembled printed article;

[0068] FIG. 2 is a perspective view of an unfolded printed sheet before assembly;

[0069] FIG. 3 shows a backing film being peeled off a printed sheet to reveal an adhesive-covered surface;

[0070] FIG. 4 is a plan view of capacitive touch elements, contact lands and interconnecting tracks on a printed sheet;

[0071] FIG. 4a is a more detailed view of capacitive touch elements and conductive tracks shown in FIG. 4;

[0072] FIG. 4b illustrates a threshold level for triggering a response;

[0073] FIG. 5 shows steps during assembly of the printed article shown in FIG. 1;

[0074] FIG. 6 is a side view illustrating coupling of a contact lands and contact pads through is an adhesive layer;

[0075] FIG. 7 illustrates a step during assembly of the printed article shown in FIG. 1;

[0076] FIGS. 8a to 8g illustrate steps during a first process of assembly;

[0077] FIG. 9 is a flow diagram of a first process of assembly of a printed article;

[0078] FIG. 10 is a flow diagram of a second process of a printed article; and

[0079] FIG. 11 is a plan view of an open battery flap.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0080] FIG. 1 shows a capacitive touch device 1 in the form of a vinyl record sleeve insert.

[0081] The capacitive touch device 1 is pairable with a Bluetooth (RTM) enabled mobile device, such as a smart phone, and can be used to provide input signals for controlling the mobile device as described, for example, in WO 2013 117917 A2.

[0082] Referring to FIGS. 1 to 5, the insert 1 comprises a single sheet 2 (best seen in FIG. 5) of card which is folded in on itself along first and second fold lines 3.sub.1, 3.sub.2(best seen in FIG. 5) to form a laminate structure 4 (best shown in FIG. 1). Paper or card can be used having a weight of, for example, about 100 to about 200 g/m.sup.2. Heavier paper or card or even cardboard can be used, for example, having a weight of up to 350 g/m.sup.2 or more.

[0083] Referring in particular to FIG. 5, the sheet 1 has first and second faces 5.sub.1, 5.sub.2 and the first fold line 3.sub.1 separates first and second wings 6.sub.1, 6.sub.2. The second fold line 3.sub.2 separates the first wing 6.sub.1 and a wing extension 6.sub.3 (herein also referred to as a “flap”). The sheet 2 has first and second ends 7.sub.1, 7.sub.2 and first and second edges 8.sub.1, 8.sub.2.

[0084] Referring in particular to FIG. 1, the second (outward) face 5.sub.2 of the second wing 6.sub.2 supports printed indicia 9. In this case, the printed indicia 9 include an image of a DJ mixing desk including images of first and second turntables 10.sub.1, 10.sub.2, a crossover slider 11 and other buttons 12.

[0085] The second wing 6.sub.2 includes a tongue-shaped flap 13 held down by a transparent sticker 14. The sticker 14 can be peeled off the area surrounding the flap 13 or entirely removed to allow the flap 13 to be lifted and access a coin cell 15 held in a holder 16 mounted on a circuit board 17 which also supports a microcontroller 18 providing Bluetooth (RTM) wireless connectivity. After the cell 15 has been replaced, the user can reapply or re-stick the sticker 14 or a new sticker (not shown).

[0086] The second wing 6.sub.2 also includes a through-hole 19 which allows ambient light to pass to a photodiode 20 on the circuit board 17. This can be used to pass a signal (not shown) to the microcontroller 18 to switch the microcontroller 18 into a power-saving mode.

[0087] Referring in particular to FIG. 4, the first face 5.sub.1 of the first wing 6.sub.1 supports a plurality of electrically-conductive pads 21 for providing capacitive touch switches, an array of electrically-conductive pads 22 for providing contact lands for contact pads 23 (FIG. 6) on the circuit board 17 and electrically-conductive tracks 24 interconnecting conductive pads 21, 22. The conductive pads 21, 22 and tracks 24 comprise carbon-based conductive ink formed by printing, for example, by lithographic or ink-jet printing process.

[0088] Each conductive switch 21 has a surface area which is sufficiently large (e.g.>0.2 cm.sup.2) to provide a capacitive touch pad. Each conductive pad 22 has an area which is sufficiently large to provide electrical capacitive or resistive contact to a contact pad 23 (FIG. 6) on the circuit board 17 (FIG. 6).

[0089] Some of the conductive switches 21 are arranged in an annular array to provide first and second capacitive touch wheels 25.sub.1, 25.sub.2. Other conductive switches 21 are arranged in a linear array to provide a capacitive touch slider 26. Other conductive switches 21 provide simple capacitive touch buttons 27.

[0090] The printed indicia 9 and the conductive switches 21 are positioned so that, when the second wing 6.sub.2 is folded over onto the first wing 6.sub.1, the images of first and second turntables 10.sub.1, 10.sub.2, crossover slider 11 and other buttons 12 are aligned with corresponding capacitive touch wheels 25.sub.1, 25.sub.2, capacitive touch slider 26 and capacitive touch buttons 27.

[0091] The conductive tracks 24 have a width, w, which is sufficiently small (e.g.<1 mm) so as to reduce capacitive coupling with a finger. As shown in FIG. 4, a conductive track 24 may include a section 28 having a ladder-shaped arrangement as described, for example, in WO 2012 101448 A2 which can be used to help to reduce capacitance per unit length of a track 24 without significantly reducing its conductivity.

[0092] Referring in particular to FIGS. 2, 3 and 4, the first face 5.sub.1 of the sheet 2, which includes the conductive pads 21, 22, the conductive tracks 24 and unprinted areas 28, is coated with adhesive 29. In this case, the adhesive 29 is covered by a backing layer 30 which can be peeled away to reveal the adhesive 29.

[0093] The adhesive 29 need not applied across all of the first face 5.sub.1 of the sheet 2. For example, adhesive 29 may be applied in selected areas including, for example, on just the first or second wing 6.sub.1, 6.sub.2 and/or around the edges of the wing(s) 6.sub.1, 6.sub.2.

[0094] An adhesive 29 need not be applied prior to assembly. The adhesive 29 can be applied during assembly. The adhesive 29 can be applied to the required areas by spraying an aerosol-based adhesive, using an adhesive stick, painting or printing liquid-based adhesive or by applying adhesive tape. The adhesive 29 may one which is curable, for example, using heat or UV light.

[0095] Referring to FIG. 4a, a portion of the capacitive touch slider 26 is shown in more detail.

[0096] The touch slider 26 is supported directly on the first face 5.sub.1 of sheet 2 and includes, among others, first, second, third, fourth, fifth and sixth co-planar capacitive touch switches 21.sub.1, 21.sub.2, 21.sub.3, 21.sub.4, 21.sub.5, 21.sub.6 in a row. Conductive tracks 24.sub.1, 24.sub.2, 24.sub.3, 24.sub.4 are also supported directly on the first face 5.sub.1 of the sheet 2, i.e. on the same face as the capacitive touch switches 21.sub.1, 21.sub.2, 21.sub.3, 21.sub.4, 21.sub.5, 21.sub.6.

[0097] A first conductive track 24.sub.1 interconnects first and fifth capacitive touch switches 21.sub.1, 21.sub.5. A second conductive track 24.sub.2 interconnects second and sixth capacitive touch switches 21.sub.2, 21.sub.6. Third and fourth conductive tracks 24.sub.3, 24.sub.4 are connected to the third and fourth capacitive touch switches 21.sub.3, 21.sub.4 respectively.

[0098] The third and fourth capacitive touch switches 21.sub.3, 21.sub.4 are adjacent and are electrically isolated from each other. The third and fourth capacitive touch switches 21.sub.3, 21.sub.4 are separated by a channel 31 having a width w.sub.c.

[0099] The first and fifth capacitive touch switches 21.sub.1, 21.sub.5 are electrically isolated from the third and fourth capacitive touch switches 21.sub.3, 21.sub.4. However, the first conductive track 24.sub.1, which interconnects the two switches 21.sub.1, 21.sub.5, runs through the channel 31.

[0100] Likewise, second and sixth capacitive touch switches 21.sub.2, 21.sub.6 are electrically isolated from the third and fourth capacitive touch switches 21.sub.3, 21.sub.4 and the second conductive track 24.sub.2, which interconnects the two switches 21.sub.2, 21.sub.6, runs through the channel 31.

[0101] In the channel 31, the first and second conductive tracks 24.sub.1 , 24.sub.2 have a width w.sub.t. The channel width w.sub.c is at least three times, preferably at least five times, the track width w.sub.t. The tracks 24.sub.1, 24.sub.2 are about 0.1 mm to 0.5 mm thick in the channel 31.

[0102] Thus, as the user passes their finger over the slider 26 over the third and fourth capacitive touch pads 21.sub.3, 21.sub.4, it can activate the third and fourth capacitive touch pad 21.sub.3, 21.sub.4, but not the other pads 21.sub.1, 21.sub.2, 21.sub.5, 21.sub.6 while the finger is over the channel 31.

[0103] Referring also to FIG. 4b, the microcontroller 18 (FIG. 5) provides, among other functions, a capacitive touch controller. The microcontroller 18 is programmed to have a sensing threshold 32 selected such that, in response to a user's finger being directly over a capacitive touch pad 21 it has a signal level 33 which exceeds the threshold level 32 and generates a trigger signal (not shown) indicating that the capacitive touch switch 21 has been “pressed” (i.e. activated), but when a user's finger is over a conductive track 24, the measured signal level 34 falls below the threshold level 32 and so no trigger signal is generated.

[0104] A similar arrangement is user for the conductive touch wheels 25.sub.1, 25.sub.2.

[0105] Referring to FIG. 5, as mentioned earlier, a second fold line 3.sub.2 separates the first wing 6.sub.1 and a wing extension 6.sub.3.

[0106] The wing extension 6.sub.3 has a frame portion 35 which defines an aperture 36. The aperture 36 is dimensioned to accommodate the circuit board 17 and is positioned so that when the wing extension 6.sub.3 is folded over onto the first wing 6.sub.1 is creates a shallow cavity over the contact lands 22.

[0107] The wing extension 6.sub.3 can be replaced by or augmented by a separate sheet having an aperture. In some cases, the wing extension 6.sub.3 can be omitted.

[0108] Referring also to FIG. 6, even if a low-conductivity adhesive 29 covers contact lands 22, a contact land 22 and a corresponding contact pad 23 on the circuit board 17 can still be electrically coupled.

[0109] First, the contact land 22 and corresponding contact pad 23 can be coupled capacitively as described, for example, in WO 2014 096772 A1.

[0110] Secondly, the contact land 22 and corresponding contact pad 23 can be coupled resistively as described, for example, in PCT/GB2014/052832. The adhesive 29 preferably should have a sheet resistance R.sub.s of at least 0.5 MΩ/sq.

[0111] However, as mentioned earlier, adhesive 29 may be applied to selective areas of the sheet. If the adhesive 29 is non conductive, then it can be omitted in the region over the contact lands 22. Alternatively, an adhesive 29 which is conductive may be used in which case it may be applied in a dot pattern as described in WO 2013 128198 A2.

[0112] Referring in particular to FIGS. 2, 5 and 7, the device 1 can be assembling by removing the backing paper 30 (or applying an adhesive 29 on the first face 5.sub.1 of the sheet 2), folding over the wing extension 6.sub.3 onto the first wing 6.sub.2, placing the circuit board 17 onto the contact lands 22 on the sheet 2 and then folding the second wing 62 onto the first wing 6.sub.1.

[0113] Referring also to FIGS. 8a to 8g and 9, a specific way of assembling the device 1 is shown.

[0114] The backing paper 30 is removed except in area 39 on the second wing 6.sub.2 (step S1-1). The flap 6.sub.3 is folded and stuck onto the first wing 6.sub.1 (step S1-2). The second wing 6.sub.2 is then folded over (step S1-3). The partially assembled device 1′ can be run through a press 41 (step S1-4). The remaining backing paper 30 can be removed (step S1-5) and the circuit board 17 can be placed onto the first wing (step S1-6). The circuit board 17 can be placed with or without the battery 18 in place. The rest of the second wing 6.sub.2 is folded over (step S1-7). If not already in place, the battery 18 is inserted (step S1-8). The sticker 14 is applied to the flap 13 (step S1-9).

[0115] Referring to FIG. 10, another ways of assembling the device 1 is shown.

[0116] The process is similar to that described earlier with reference to FIG. 9. However, the whole device, including circuit board, is passed through the press 41. This may be used particularly when the sheet is at least as thick as the circuit board 17 and any components supported on the board 17 or where an additional spacer insert is used and so the board or components are not subjected to the pressure of the press 41.

[0117] FIG. 11 shows the coin cell cover flap 13 is open so as to reveal the coin cell holder 16.

[0118] Referring to FIG. 11, the flap 13 and the corresponding aperture 42 formed in the sheet 2 may have inwardly-concave arcuate edges 43.sub.1, 43.sub.2, 43.sub.3. The arcuate edges 43.sub.1, 43.sub.2, 43.sub.3 in the sheet 2 form spaces 44.sub.1, 44.sub.2 which allow a tool (not shown) to access the coin cell holder 16 and allow it to push out the cell 15 out. Preferably, the flap is formed by cutting slits in the sheet 2 and so is unitary with the rest of the sheet.

[0119] It will be appreciated that many modifications may be made to the embodiments hereinbefore described. Such modifications may involve equivalent and other features which are already known in the design, manufacture and use of capacitive touch devices and component parts thereof and which may be used instead of or in addition to features already described herein. Features of one embodiment may be replaced or supplemented by features of another embodiment.

[0120] The article need not be a vinyl record insert. The article may be a pamphlet, flyer, leaflet or other single sheet article. The printed article may be a promotional item. The printed article may be a map or a cover for a map. The printed article may be postcard or greetings card. The printed article may be a map or a cover for a map. The printed article may be an insert for another item, such as a magazine, book or other product. The printed article may be an insert in or part of product packaging. The product may be media (such as a vinyl record or a CD). The product may be an article of clothing, game or food stuff (such as box of cereal). The insert may be free or bound into another item. The printed article may be a game or playing card. The printed article may be a point-of-sale display.

[0121] The device may include three, four, five or more wings. The wings need not be all the same size.

[0122] The fold lines need not all be parallel. For example, one or more fold lines may be perpendicular to another fold line. Thus, a device may be assembled from an ‘L’-shaped, ‘T’-shaped, ‘+’-shaped or other, more complex layouts.

[0123] The printed article may include other forms of output device, such as piezoelectric buzzer or other sound-emitting device, and/or one or more light-emitting diodes or other light-emitting or display device(s).

[0124] Although claims have been formulated in this application to particular combinations of features, it should be understood that the scope of the disclosure of the present invention also includes any novel features or any novel combination of features disclosed herein either explicitly or implicitly or any generalization thereof, whether or not it relates to the same invention as presently claimed in any claim and whether or not it mitigates any or all of the same technical problems as does the present invention. The applicants hereby give notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present application or of any further application derived therefrom.