Field of the Invention

The present invention relates to a capacitive touch-enabled printed article, such as a capacitive-touch enabled magazine.

Background

Electronic components are increasingly being incorporated into printed items, such as books, magazine, posters and greeting cards, to allow these items to become interactive. In particular, capacitive touch sensors are being incorporated into items to allow a user to provide input and the item or a device, such as mobile phone, wirelessly connected to the item to respond. Examples of such items are described in GB 2 464 537 A and WO The battery life of such a capacitive touch-enabled printed article is limited. One approach to increasing the lifetime of the electronic part of the printed article is to fit the battery at point of sale, rather than during assembly. However, this approach may be impractical.

Summary

According to a first aspect of the present invention there is provided a capacitive touch- enabled printed article. The article comprises at least one capacitive touch switch (for example in the form of a pad of conductive ink), a controller (such as a microcontroller) connected to the at least one capacitive touch switch and a photodetector (such as a photodiode) connected to the controller. The photodetector has a light-sensing face. The controller is operable in first and second states. The controller is configured to poll the photodetector and, in response to determining that the light-sensing face is not exposed to light, to operate in the first state and, in response to determining that the light-sensing face is exposed to light, to operate in the second state.

The article may comprise a cover for a user-presentable surface of a portion of the article and the at least one capacitive touch switch maybe provided in or under the cover or in or under the user-presentable surface. The sensing face may be arranged such that the sensing face is covered when the cover covers the user-presentable surface. The first state maybe a relatively low power consumption state and the second state may be a relatively high power consumption state. In the first state, the controller may be arranged to poll the photodetector and, in response to determining that sensing face is exposed to light, to switch to the second state.

Thus, the battery can be fitted at time of assembly. Unless and until the article is used, i.e. the cover is lifted, the controller lies in the low power consumption state. When the article is used, i.e. the cover is lifted, then controller switches to the high power consumption state in which capacitive touch functionality is enabled.

In the first state, the controller may respond with a first set of responses to actuation of the at least one capacitive touch pad and, in the second state, the controller may respond with a second set of responses to actuation of the at least one capacitive touch pad and, in the second state.

Thus, the photodetector can be disposed in a cover or a page of printed matter (such as a pamphlet, magazine or book) and be used to determine which side of a page is open. The controller can be arranged to provide different responses depending on which side of the page is open. The cover may comprise wood-fibre-based material, such as paper or card. The cover may comprise a semi-gloss paper or card. The cover may comprise material having a weight exceeding 120 grrr ² . The printed article may comprise a sheet supporting the at least one capacitive touch pad, the controller and photodetector supported by the cover. This allows capacitive touch functionality to be incorporated easily into the printed item, for example, in the form of an insert. The sheet may be bonded, e.g. using an adhesive, to an inner face of the cover (i.e. the face facing the user-presentable surface). The sheet may comprise wood-fibre-based material, such as paper or card.

The user-presentable surface may be a face of an endsheet or an end page in a text block. The cover may be foldably openable to reveal the user-presentable surface.

The article may be a printed article, such as a multiple-fold pamphlet, magazine or book. The printed article may be a board game. The cover may be separable from the article. Thus, the cover can be an instruction sheet or a part of disposable product packaging (e.g. primary, secondary or tertiary packaging) for an article.

According to a second aspect of the present invention there is provided a method of operating a controller comprising measuring a photodetector, determining whether the photodetector is detecting light exceeding a predetermined level, upon a negative determination, operating in a first capacitive touch operating state and, upon a positive determination, operating in a second capacitive touch state. The method may comprise, in the first state, measuring the photodetector, determining whether the photodetector is detecting light exceeding a predetermined level, upon a positive determination, switching to the second state and upon a negative

determination, waiting a predetermined time before measuring the photodetector again. The method may comprise, in the second state, measuring a capacitive touch switch. The method may comprise, in the first state, not measuring the capacitive touch switch.

The method may comprise, in the second state, not measuring the photodetector.

The method may comprise, in the first state, responding with a first set of responses to actuation of the at least one capacitive touch pad and, in the second state, responding with a second set of responses to actuation of the at least one capacitive touch pad and, in the second state.

According to a third aspect of the present invention there is provided a computer program which, when executed by a controller (such as microcontroller), causes the controller to perform the method according to second aspect.

According to a fourth aspect of the present invention there is provided a computer readable medium (for example memory in microcontroller) storing the computer program according to the third aspect.

Brief Description of the Drawings

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

Figure 1 is a perspective view of a magazine when closed;

Figure 2 is a perspective view of a magazine in when open;

Figure 3 is a schematic block diagram of a capacitive touch sensor circuit including a controller;

Figure 4 illustrates a masking arrangement which can be used to keep a photodetector covered until a magazine is assembled; and

Figure 5 is a process carried out by the microcontroller shown in Figure 3.

Detailed Description of Certain Embodiments

Referring to Figures 1 and 2, a capacitive touch-enabled printed article 1 is shown. The printed article 1 takes the form of a magazine, i.e. a periodical publication.

The magazine 1 has front and back covers 2, 3 and a set of pages 4 bound, e.g. using perfect binding, between the covers 2, 3 along a spine 5. The front cover 2 has a first, front face 6 and a second, inside face 7. The magazine 1 includes an insert 8 lying behind the front cover 6, preferably glued to the inside face 7 using an adhesive (not shown). The insert 8 may be covered by a cover sheet 9 thereby sandwiching the insert 8 between the front cover 2 and the cover sheet 9. The cover sheet 10 includes an aperture hole 10. The insert 8 provides a capacitive touch device 11 (Figure 3) which can be used to detect user input when a user touches the front cover 2.

The insert 8 comprises a sheet 12 supporting one or more capacitive touch switches 13, a set of one or more conductive tracks 14 and a set of one or more connection terminals 15. The one or more switches 13, the one or more conductive tracks 14 and one or more connection terminals 15 preferably comprise carbon-based conductive ink printed on the sheet 12, e.g. using lithographic printing or ink-jet printing. However, the one or more switches 13, the one or more conductive tracks 14 and one or more connection terminals 15 may comprise a silver-based conductive ink or foil. The touch switches 13 may be arranged in an array to form an x-y touchpad and position may be found by interpolation, as described in WO 2014/ 057251 Ai. The insert 8 includes a circuit board 16 supporting a set of one or more connection terminal (not shown) for coupling to the corresponding connection terminals 15 on the sheet 2, a microcontroller 17 a battery 18 and a photodetector 19, e.g. in the form a photodiode. The connection terminals 15 on the sheet 12 and the connection terminals (not shown) on the circuit board 16 are coupled capacitively through the sheet 12, as described in WO2014/096772 Ai. By using capacitive coupling or by using through- board wiring, the circuit board 16 can be orientated with the photodetector 19 facing away from the front cover 2, i.e. towards the inside of the magazine 1. As shown in Figure 2, the photodetector 19 has a sensor face 20 which is aligned with aperture 10 in the cover sheet 9 thereby allowing light to reach the sensor face 20 when the front cover 2 is folded back and no other pages 4 are folded back so as to cover the front cover 2. Thus, when the magazine 1 is closed such that the sensor face 20 faces an upper face 21 of the first page 4, light does not reach the sensor face 20. As will be explained, hereinafter, the photodetector 19 can be used to detect when the magazine 1 is opened for the first time which can be used to enable touch functionality.

Referring to Figure 3, the microcontroller 17 comprises at least one CPU core 22, at least one analogue-to-digital converter 23 and non-volatile memory 24 storing application software 25. The microcontroller 17 may include an integrated wireless network interface module 26, such as Bluetooth (RTM) Smart module.

Additionally or alternatively to the integrated wireless network interface module 26, the capacitive touch device 11 may optionally include one or more external output devices 27, such as a speaker, a wireless network interface module and/ or light emitting diodes.

The front cover 2 may include text and images (not shown) which the user can touch. This action can be detected by one or more underlying touch switches 13. This can be used to control an external device, such as a mobile phone or tablet, for example as described in WO 2013/ 117917 Ai, and/ or to control an embedded output device 27.

Referring to Figure 4, a masking arrangement is shown which allows the magazine to be bound while keeping the photodetector 27 in the dark. In Figure 5, the vertical scale (z) between the cover and first page is exaggerated. The aperture 11 may be covered with an opaque sticker 28 having a tab 29 extending beyond the edge 30 of magazine which can be pulled to remove the sticker 28 and the tab 29 when the magazine 1 is closed.

Figure 5 illustrates operation of the device 11.

Referring to Figures 1 to 5, when the magazine 1 is bound, the battery 18 is inserted into a holder (not shown). The device 11 may be disabled for a given period of time so as to allow time for the cover 2 to be closed or a masking arrangement may be used so as to ensure that no light reaches the photodiode 19 until the cover 2 is closed.

The microcontroller 17 is in a first state which consumes little power (step Si). In a low-power consuming state, the controller 17 may wake up from a sleep cycle (step S2) and poll the photodetector 19 (step S3). By measuring current from the photodetector 19, the microcontroller 17 can determine whether light is detected and, thus, whether the magazine 1 has been opened (step S4).

If the microcontroller 17 determines that no light is incident on the photodetector 19, it go back to sleep for a given period of time (step S5). The period of time may be greater than 1 second. The period of time may be long as 10 seconds or more.

If the microcontroller 17 determines that light is falling on the photodetector 19, then it switches into a second state (step S6), which involves polling the capacitive touch switches (step S7). The switch from first to second state may be irreversible, i.e. once the controller 17 has switched from the first state to the second state, it stays in the second state regardless of whether or not the magazine 1 is subsequently closed. However, in some

embodiments, the microcontroller 17 may re-enter the first state after a given period of inactivity has elapsed, e.g. 1 minute or more.

Thus, while in the first state, the device 11 can consume little power which can help to extend battery life.

It will be appreciated that many modifications may be made to the embodiments hereinbefore described. Additionally or alternatively, an insert may be provided for the back cover.

A system on a chip (SoC) and external (i.e. off-chip) memory may be used. The photodetector need not be used for power saving, but can be used to determine on which page of printed matter, for example of a book or magazine, is open. This can allow responses detected with an x-y touchpad, such as the one described in WO 2014/057251 Ai, to differ according to which page is open. For example, the pages may be translucent, each page having a known non-zero transmittance. Thus, the transmittance for a one page is greater than transmittance for two pages etc. By measuring the light intensity falling on the photodetector, the page may be identified. Alternatively, a plurality of photodetectors may be provided. For example, an array of spaced-apart photodetectors may be provided in the cover. The pages may have correspondingly aligned windows. Thus, when the printed matter is open on a first page, all photodetectors may be exposed and, when open on a second page, all but one photodetector are exposed etc. Thus, by determining which photodetector or photodetectors is or are exposed to light, the open page can be identified. Alternatively, a photodetector may be embedded in each page.