GB2606748A

GB2606748A - Keyboard

Info

Publication number: GB2606748A
Application number: GB2107178.2A
Authority: GB
Inventors: Borysyonok Vasily; Zakreuski Dzmitry; Sakovich Raman; Krupiankou Mikhail; Lahutsik Yury
Original assignee: Clevetura Ltd
Current assignee: Clevetura Ltd
Priority date: 2021-05-19
Filing date: 2021-05-19
Publication date: 2022-11-23
Also published as: GB202107178D0

Abstract

A keyboard comprises a plurality of keys and a touch sensor for detecting a touch of a user on the keys. The keyboard is arranged to detect a keypress relating to the keys using the touch sensor, and to process signals from the touch sensor based on: a first scanning mode associated with a first scanning period or rate and a second scanning mode associated with a second scanning period or rate. The first scanning period or rate is different than the second scanning period or rate. Each key may be associated with a conductive (e.g. metal oxide semiconductor) coating, such that when the key is pressed the corresponding coating moves relative to the touch sensor, which may be a mutual or self-capacitance sensor. The touch may operate based on a third scanning mode associated with a third scanning period, the second scanning period being greater than the third scanning period. The keyboard may be configured to change between scanning modes based on detecting of a keypress, not detecting a keypress for a threshold time (e.g. 10 ms), or detecting a signal, and/or an integrated signal with a magnitude that exceeds a threshold magnitude.

Description

Keyboard

Field of the disclosure

The present disclosure relates to a keyboard. In particular the present disclosure relates to a keyboard corn prising a touch sensor.

Background to the Disclosure

A typical method of controlling the operation of computer devices is to use a keyboard and/or a touchpad. These components enable a user to interact with a computer, e.g. to send instructions to a processor. Ideally, these components are user-friendly; however, present keyboards and touchpads have a number of flaws.

A particular problem is that in order to use a conventional touchpad after typing a user must move their hand from the keyboard to the touchpad. In order to begin typing again at full speed, the user must move this hand back from the touchpad to the keyboard. While this movement can be quite quick, it is likely to be repeated thousands of times over the course of a year, which can lead to a significant cumulative time and focus requirement. Therefore, it would be beneficial to integrate a touch sensor with a keyboard to reduce the need for this movement. However, this integration can lead to a keyboard that lacks user friendliness and is bulky.

A solution to this problem is desired. Summary of the Disclosure According to an aspect of the present disclosure, there is described: a keyboard comprising: a plurality of keys; and a touch sensor for detecting a touch of a user on the keys; wherein the keyboard is arranged to detect a keypress relating to the keys using the touch sensor; and wherein the keyboard (e.g. a control unit of the keyboard) is arranged to process signals from the touch sensor based on: a first scanning mode associated with a first scanning period; and a second scanning mode associated with a second scanning period; wherein the first scanning period is greater than the second scanning period.

According to an aspect of the present disclosure, there is described: a keyboard comprising: a plurality of keys; and a touch sensor for detecting a touch of a user on the keys; wherein the keyboard is arranged to detect a keypress relating to the keys using the touch sensor; and wherein the keyboard (e.g. a control unit of the keyboard) is arranged to process signals from the touch sensor based on: a first scanning mode associated with a first scanning rate; and a second scanning mode associated with a second scanning rate; wherein the second scanning rate is greater than the first scanning rate.

The first mode may be a touch scanning mode. The second mode may be a keypress scanning mode.

Preferably, each key is associated with a conductive coating, such that when said key is pressed the corresponding coating moves relative to the touch sensor.

Preferably, each coating is arranged on a transmittal mechanism of the corresponding key. Preferably, each coating is arranged on: an exterior surface, an interior surface, and/or a tip of the transmittal mechanism. Preferably, the transmittal mechanism comprises a dome. -2 -

Preferably, the coating comprises a metal coating. Preferably, the coating comprises a metal oxide semiconductor.

Preferably, the touch sensor comprises a capacitive sensor. Preferably, the touch sensor comprises a mutual capacitance sensor.

Preferably, the touch sensor comprises a self capacitance sensor.

Preferably, the touch sensor is arranged to operate in: a mutual capacitance mode and a self capacitance mode.

Preferably, the first scanning mode comprises a mutual capacitance mode and the second scanning mode comprises a self capacitance mode. Where the second scanning mode comprises a self capacitance mode, the second scanning mode may be a keypress detection mode.

Preferably, the keyboard is arranged to operate in only the first and second scanning modes.

Preferably, each of the first scanning mode and the second scanning mode comprises a mutual capacitance mode. Where the second scanning mode comprises a mutual capacitance mode, the second scanning mode may be a keypress scanning mode.

Preferably, the touch sensor is arranged to operate based on a third scanning mode associated with a third scanning period and/or a third scanning rate. Preferably, the third scanning rate is greater than the second scanning rate. Preferably, the third scanning period is less than the second scanning period.

Preferably, the third scanning rate is at least 500Hz. Preferably, the third scanning rate is in the 20 range of 500Hz -1000Hz.

Preferably, the third scanning period is no more than 2ms. Preferably, the third scanning period is in the range of 1ms -2ms.The third scanning mode may be a keypress detection mode.

Preferably, the third mode comprises a self capacitance mode.

Preferably, the first mode and/or the second mode comprises a mutual capacitance mode.

Preferably, the touch sensor is arranged to switch from the first mode to the second mode based on the detecting of a keypress. Preferably, the first scanning mode is the default mode.

Preferably, the touch sensor is arranged to switch from the first mode to the third mode based on the detecting of a keypress.

Preferably, the touch sensor is arranged to switch from the third mode to the second mode based on the detecting of a keypress.

Preferably, the touch sensor is arranged to switch from the second mode to the first mode in dependence on the touch sensor not detecting a keypress for a threshold time.

Preferably, the touch sensor is arranged to switch from the third mode to the first mode in dependence on the touch sensor not detecting a keypress for a threshold time.

Preferably, the threshold time is no more than 10ms.

Preferably, detecting a keypress comprises detecting a signal with a magnitude that exceeds a threshold magnitude. -3 -

Preferably, the keyboard is arranged to output only touch events in the first scanning mode and/or to output only keypress events in the second scanning mode and/or the third scanning mode.

Preferably, the touch sensor is arranged to operate in the first scanning mode and the second scanning mode alternately.

Preferably, the touch sensor is arranged to operate in the first scanning mode and the second scanning mode simultaneously.

Preferably, the touch sensor is arranged to operate using a combined frame, the combined frame comprising a first frame associated with the first scanning mode and one or more second frames associated with the second scanning mode.

Preferably, the combined frame comprises a plurality of second frames.

Preferably, the keyboard is arranged to detect a touch event and/or a keypress event by integrating a signal received by the touch sensor.

Preferably, the keyboard is arranged to detect a touch event by integrating a signal received by the touch sensor over the first scanning period.

Preferably, the keyboard is arranged to detect a keypress event by integrating a signal received by the touch sensor over the second scanning period.

Preferably, the keyboard is arranged to detect a keypress event by detecting a signal with a magnitude that exceeds a threshold magnitude.

Preferably, the keyboard comprises a control unit.

Preferably, the control unit is arranged to control the keyboard and/or the touch sensor.

Preferably, the control unit is arranged to process signals from the touch sensor in order to detect touch events and/or keypress events.

Preferably, the control unit is arranged to distinguish between a touch and a keypress.

Preferably, the control unit is arranged to distinguish between a touch and a keypress based on one or more of: a magnitude of a change measured by the touch sensor; a duration of a change measured by the touch sensor; a rate of a change measured by the touch sensor; a direction of a movement measured by the touch sensor; and a mode of the keyboard.

Preferably, the keyboard is arranged to operate in a plurality of input modes. Preferably, the scanning mode used by the touch sensor is dependent on a selected input mode. Preferably, the input modes include a pointer input mode and a keypress input mode.

Preferably, the first scanning rate is no more than 200Hz. Preferably, the first scanning rate is in the range of 100Hz -200Hz.

Preferably, the first scanning period is at least 5ms. Preferably, the first scanning period is in the range of 5ms -10ms.

Preferably, the second scanning rate is at least 200Hz. Preferably, the second scanning rate is in the range of 200Hz -500Hz. -4 -

Preferably, the second scanning period is no more than 5ms. Preferably, the second scanning period is in the range of 2ms -5ms.

According to another aspect of the present disclosure, there is described the aforesaid touch sensor.

According to another aspect of the present disclosure, there is described the aforesaid control unit.

Preferably, the touch sensor comprises a plurality of rows and columns of electrodes.

Preferably, the touch sensor is arranged so that the intersections of the rows and columns of electrodes are located beneath the keys and/or beneath the coatings.

Preferably, the touch sensor is arranged so that the keys and/or the coatings are located above intersections of the rows and columns of electrodes Preferably, the keyboard is arranged to detect a keypress relating to the keys using the touch sensor.

According to another aspect of the present disclosure, there is described a keyboard comprising: a plurality of keys; and a touch sensor for detecting the touch of a user on the keys; wherein the keyboard is arranged to detect a keypress relating to the keys using the touch sensor.

Preferably, the touch sensor comprises a capacitive sensor.

Preferably, the touch sensor comprises a mutual capacitance sensor. Preferably, the touch sensor comprises a plurality of rows and columns of electrodes.

Preferably, the touch sensor is arranged so that the intersections of the rows and columns are beneath the keys.

Preferably, the keyboard comprises a coating, wherein the coating is arranged to move relative to the touch sensor when a key is pressed. Preferably the coating is arranged on a component of the keyboard. Preferably the coating is arranged on a key of the keyboard.

Preferably, each key comprises a coating such that when a key is pressed the corresponding coating moves relative to the touch sensor. Preferably each key relates to and/or comprises a plurality of coating elements.

Preferably, the touch sensor is arranged to detect a movement of the coating. Preferably, the touch sensor is arranged to detect a change in a local electric field caused by the movement of the coating.

Preferably, the coating is arranged on a/the transmittal mechanism of the keys.

Preferably, the coating is arranged on: an exterior surface, an interior surface, and/or a tip of the transmittal mechanism, preferably wherein the transmittal layer comprises a dome.

Preferably, the coating comprises a conductive coating and/or a metal coating.

Preferably the keyboard is arranged to detect a keypress based on a movement of the coating and/or based on a change in conductivity caused by a movement of the coating. -5 -

Preferably, the coating is arranged to interact with the touch sensor so as to enable the detection of the keypress.

Preferably, the coating is arranged to cause a substantial alteration in the local electric field around the touch sensor when the key is depressed so as to enable the detection of the keypress.

Preferably, the touch sensor is arranged so that the keys approach and/or impact the touch sensor when the keys are depressed.

Preferably, the touch sensor is arranged so that the coating approaches and/or impacts the touch sensor when the keys are depressed.

Preferably, the keyboard further comprises a controller for distinguishing between the touch of a user and the keypress.

Preferably, in order to distinguish between the touch of a user and the keypress, the controller is arranged to determine at least one of: a magnitude of a change measured by the touch sensor; a duration of a change measured by the touch sensor; a rate of a change measured by the touch sensor; a direction of a movement measured by the touch sensor; and a mode of the keyboard.

Preferably, the controller is calibrated to determine at least one of: a baseline output; an output corresponding to a touch input; and an output corresponding to a keypress.

According to another aspect of the present disclosure, there is described a method of manufacturing the aforesaid keyboard.

According to another aspect of the present disclosure, there is described a method of using the aforesaid keyboard.

Any feature in one aspect of the disclosure may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa.

Furthermore, features implemented in hardware may be implemented in software, and vice versa.

Any reference to software and hardware features herein should be construed accordingly.

Any apparatus feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure, such as a suitably programmed processor and associated memory.

It should also be appreciated that particular combinations of the various features described and defined in any aspects of the disclosure can be implemented and/or supplied and/or used independently.

The disclosure also provides a computer program and a computer program product comprising software code adapted, when executed on a data processing apparatus, to perform any of the methods described herein, including any or all of their component steps.

The disclosure also provides a computer program and a computer program product comprising software code which, when executed on a data processing apparatus, comprises any of the apparatus features described herein. -6 -

The disclosure also provides a computer program and a computer program product having an operating system which supports a computer program for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein.

The disclosure also provides a computer readable medium having stored thereon the computer program as aforesaid.

The disclosure also provides a signal carrying the computer program as aforesaid, and a method of transmitting such a signal.

Where the disclosure references the keyboard being arranged to operate in a certain way, this may comprise the control unit being arranged to operate in a certain way (and vice versa).

As used herein, a touch of the user may refer to a touch of the user using an appendage of the user (e.g. a finger). Equally, a touch of the user may refer to a touch of the user using an implement, such as a stylus.

The disclosure extends to methods and/or apparatus substantially as herein described with reference to the accompanying drawings.

The disclosure will now be described, by way of example, with reference to the accompanying drawings.

Description of the Drawinqs

Figure 1 shows an exemplary user device with which the apparatus described herein may be used.

Figure 2 shows a keyboard.

Figure 3 shows layers of the keyboard.

Figure 4 shows a base plate that may be included in the keyboard.

Figure 5a -5d show further layers of the keyboard that may be included in the keyboard. Figure 6a shows a touch sensor that can be used with the keyboard.

Figure 6b shows a protective layer for protecting the touch sensor of Figure 6a.

Figure 7 shows a detailed example of a touch sensor.

Figure 8 shows a transmittal mechanism for use in detecting a keypress.

Figure 9 shows a capacitive sensor suitable for use with the transmittal mechanism of Figure 8.

Figure 10 shows an illustrative signal that may occur in a receiving channel of the touch sensor.

Figures 11a and llb show methods of switching between scanning modes of the keyboard.

Description of the preferred embodiments

Referring to Figure 1, there is shown an exemplary computer device 1000.

The computer device 1000 comprises a processor in the form of a CPU 1002, a communication interface 1004, a memory 1006, storage 1008, and a user interface 1010, where the components are connected by a bus 1012. The user interface 1010 typically comprises a display 1016 and -7 -one or more input/output devices; in this embodiment the user interface 1010 comprises a keyboard 2000 and a pointer input 3000.

The CPU 1002 executes instructions, including instructions stored in the memory 1006 and the storage 1008.

The communication interface 1004 is typically a Bluetoothe interface that enables the computer device 1000 to be coupled with other devices comprising a Bluetooth® interface. It will be appreciated that the communication interface 1004 may comprise any other communications technology, such as an area network interface and/or an Ethernet interface. The communication interface 1004 may comprise a wireless interface or a wired interface, such as a universal serial bus (USB) interface.

The memory 1006 stores instructions and other information for use by the CPU 1002. Typically, the memory 1006 usually comprises both Random Access Memory (RAM) and Read Only Memory (ROM).

The storage 1008 provides mass storage for the computer device 1000. Depending on the computer device 1000, the storage 1008 is typically an integral storage device in the form of a hard disk device, a flash memory or some other similar solid state memory device, or an array of such devices.

The user interface 1012, and in particular the keyboard 2000 and the pointer input 3000 are used to control the computer device 1000, where these components enable the user to pass instructions to the CPU 1002. Typically, the pointer input comprises a touch sensor and/or a computer mouse.

The keyboard 2000 and the pointer input 3000 may be integrated with the computer device 1000 or may be removable components. For example, the keyboard 2000 and the pointer input 3000 may be connected to the computer device 1000 by an, optionally removable, wire, such as a USB 25 connection In some embodiments, the keyboard 2000 and/or the pointer input 3000 is wirelessly connected to the computer device 1000, for example using a Bluetoothe connection.

The present disclosure relates, in part, to a combined keyboard and pointer input, where a pointer input means (e.g. a touchpad) is integrated with the keyboard 2000. As an example, a capacitive sensor may be integrated with the keyboard 2000, where the capacitive sensor detects when the user touches the keys of the keyboard 2000.

It will be appreciated that as well as capacitive sensors other technologies can be used to detect a user touching the keys of the keyboard 2000. As an example, optical sensors may be used, where these optical sensors may detect movement of an object a certain distance from the keyboard 2000 and/or touchpad 3000. Similarly, pressure sensors may be used, where the pressure sensors may be included in the keys of the keyboard 2000 or placed above/below the keys. In various embodiments, the touch sensor comprises one or more of: a camera; acoustic sensors; temperature sensors; magnetic sensors (e.g. Hall sensors); piezoelectric sensors; and triboelectric sensors.

Referring to Figure 2, the keyboard 2000 is shown in more detail. -8 -

The keyboard 2000 comprises a number of keys 2002 and a connection interface 2004. The keys 2002 are arranged to detect a user input, e.g. from a user pressing the keys 2002. The connection interface 2004 is arranged to connect the keyboard to the computer device 1000. The connection interface 2004 may comprise a USB connection, a Bluetoothe interface, or a radio interface (e.g. at 2.4GHz or 5GHz).

In some embodiments, the keyboard 2000 comprises a computer device and/or comprises components similar to the computer device 1000. In particular, the keyboard 2000 may comprise a processor, a communication interface, a memory, storage, and/or a user interface. This enables the keyboard to execute instructions itself (without requiring the assistance of a separate computer device).

It will be appreciated that any layout of keyboard may be used; for example, a full-size keyboard, a 'tenkeyless' keyboard, or a '60%' keyboard. Furthermore, the layout and properties of the keys 2002 on the keyboard 2000 may vary.

Referring to Figure 3, the keyboard 2000 is typically composed of a plurality of layers.

Certain layers that may form a part of the keyboard 2000 are described with reference to Figures 4 and 5a-5d.

In particular, referring to Figure 4, there is disclosed a base plate 2010, which comprises a plurality of hook mounts 2012. The hook mounts 2012 of the base plate 2010 are arranged to pass through each other layer of the keyboard 2000 in order to attach to a keypress mechanism, such as a scissor mechanism. Various other keypress mechanisms are known in the art. The keyboard 2000 may also comprise a touch sensor (which touch sensor is typically a part of a touch sensor layer); this touch sensor is typically arranged to allow passage of the hook mounts 2012, e.g. by the touch sensor comprising holes through which the hook mounts 2012 can pass.

The hook mounts 2012 typically comprise extensions, which are designed to pass through the other layers in order to fit inside recesses of another layer. Alternatively, the hook mounts 2012 may comprise recesses, into which extensions of another layer are arranged to fit.

In some embodiments, the base plate 2010 comprises holes 2014 to allow the passage of light. This allows a backlight to be located behind the base plate 2010, where this backlight is able to provide a light that passes through the holes 2014 of the base plate 2010.

The base plate 2010 is a rigid structure that is typically formed of metal; this provides rigidity to the entire keyboard 2000.

Referring to Figures 5a -5d, there is described other layers that may form a part of the keyboard 2000.

Referring to Figure 5a, there is shown a keypress sensor layer 2020. The keypress sensor layer 2020 is arranged to record keystrokes, e.g. when a user presses the key 2002. Typically, this is achieved by arranging a plurality of sensors 2022 on the keypress sensor layer 2020, where each sensor is arranged to detect the pressing of a single key.

In some embodiments, the keyboard 2000 is a membrane keyboard. In such embodiments, the keypress sensor layer 2020 comprises a series of conductive portions with there being two conductive portions between each key. A further conductive portion is present at the base of the -9 -key, so that when the key is pressed the two conductive portions of the keyboard sensor layer 2020 are connected.

In order to determine a keypress, the keyboard 2000 typically comprises a control unit (not shown) that continuously scans the keypress sensor layer 2020 in order to determine the presence of a current. In various embodiments, the scan rate and the scan pattern of the controller differ; e.g. a higher scan rate of the controller may be desirable to reduce the latency of a keypress, but this may reduce accuracy by being more likely to pick up a false keypress.

In some embodiments, the keyboard 2000 is a mechanical keyboard and each key is connected to a separate switch. Pressing a key operates the corresponding switch, thereby a keypress can be detected.

Typically, the keyboard 2000 is a membrane keyboard and the keypress sensor layer 2030 is formed by bonding together one or more polyethylene terephthalate (PET) membranes. The plurality of keypress sensors (e.g. conductive portions) are located within the PET membranes.

Referring to Figures 5b -5d, each key 2002 typically comprises a transmittal mechanism 2030, a keypress mechanism 2040, and a keycap 2050. The keycap 2050 enables the user to interact with the remainder of the key 2002; the transmittal mechanism 2030 connects the keycap 2050 to the keypress sensor layer 2020 so that a keypress can be detected; the keypress mechanism 2040 is an optional feature of the key 2002 that is arranged to provide a stable keypress (e.g. ensure that the force resisting a keypress is relatively constant throughout the distance of travel of the key 2002).

The keypress mechanism 2040 also maintains the horizontal position of the keycap 2050 throughout the travel of the key to ensure that the keycap 2050 being pressed (at any location on the keycap 2050) results in a depression of the transmittal mechanism 2030.

Typically, the transmittal mechanisms 2030 are mounted on the touch sensor layer 2020. In some embodiments, the transmittal mechanisms 2030 are arranged so that the depression of a keycap results in a part of a corresponding transmittal mechanism impacting the touch sensor layer 2020. In some embodiments, the transmittal mechanisms 2030 are arranged so that the depression of the keycap 2050 results in a part of a corresponding transmittal mechanism passing through a hole of the touch sensor layer 2020.

Referring to Figure 5b, there is shown an embodiment of the transmittal mechanisms 2030. In this embodiment, the transmittal mechanisms 2030 comprise a plurality of silicone domes 2032, where there is a silicone dome for each key of the keyboard 2000. The silicone domes 2032 are arranged so that when the user presses a key of the keyboard 2000 a corresponding silicone dome is compressed, and this dome actuates a sensor of the keypress sensor layer 2020. The sensor 2022 is thus able to detect that a key has been pressed. The silicone domes 2032 also cushion the depression of the keys 2002 and provide a return force that raises a key once the user has released pressure on that key.

It will be appreciated that there are a number of other types of transmittal mechanisms may be used to detect the depression of a key, such as metal domes or mechanical linkages (e.g. push switches and/or springs).

-10 -Referring to Figure 5c, there is shown an embodiment of the keypress mechanism 2040, in this embodiment of the keypress mechanism 2040 is a scissor mechanism. The scissor mechanism comprises two interlocking parts that are typically composed of plastic. The interlocking parts are arranged to bias the key 2002 in a raised position and/or to resist the depression of the key 2002.

When the user applies pressure to the key 2002, the key 2002 is depressed, which forces the base of each interlocking part away from the base of the other interlocking part so that the key 2002 can be depressed. When the user releases the pressure, the biasing force acts to raise the key 2002. This movement is shown in Figure Sc.

Referring to Figure 5d, there is shown a keycap 2050. The keycap 2050 is placed on top of the transmittal mechanism and the keypress mechanism 2040 so that pressure applied to the keycap 2050 is transmitted to the transmittal mechanism 2030 and the keypress mechanism 2040. The keycap 2050 protects the remainder of the layers to minimise wear and increase the lifespan and usability of the keyboard 2000. Typically, each keycap has a different symbol printed onto it, e.g. a letter or a number, to enable the user to determine the consequence of depressing the keycap 2050 (e.g. depressing a keycap 2050 that has "F" printed on it will result in the letter f being typed and shown on the display 1012).

The keypress mechanism 2040 is mounted on a layer of the keyboard 2000, which may be a separate layer to those described above. In typical keyboards the keypress mechanism 2040 is mounted to a layer that is located towards the top of the keyboard 2000, e.g. the keypress mechanism 2040 is mounted to a layer immediately below the level of the keypress mechanisms 2040.

The present disclosure considers, in part, a keyboard in which the hook mounts 2012 on which the keypress mechanisms 2040 are mounted are a part of the base plate 2010. Each other layer of the keyboard 2000 is arranged so that the hook mounts 2012 are able to pass through these layers in order to attach to the keypress mechanisms 2040; in particular, a touch sensor layer is arranged to enable the passage of the hook mounts. The base plate 2010 therefore provides both rigidity for the keyboard 2000 and a mounting means for the keypress mechanisms 2040. This enables each keypress mechanism 2040 to be secured without the need for a separate securing layer, which allows the provision of a thin keyboard.

Touch sensor Referring to Figure 6a, there is shown a touch sensor in the form of a touch sensor layer 2060 that is suitable for inclusion within the keyboard 2000. The touch sensor layer 2060 is arranged to detect the presence of an object on or above the keyboard 2000.Typicallty, this detection is achieved by the touch sensor layer comprising a plurality of sensing elements. In this embodiment, the touch sensor layer 2060 comprises a capacitive sensor that is capable of detecting a user's finger touching the keyboard 2000 due to a change in the local electric field caused by the finger. Typically, the touch sensor layer 2060 is arranged to determine one or more of: a number of objects above the keyboard 2000, a position of those objects, a motion of those objects, a trajectory of those objects, and/or a speed of those objects.

In some embodiments, the touch sensor layer 2060 comprises other sensors, such as optical sensors, pressure sensors, accelerometers, or audio sensors. Generally, the touch sensor layer 2060 may comprise any sensor and/or component that is capable of detecting the position and/or movement of a user and/or object.

Where a capacitive sensor is used the capacitive sensor typically comprises a grid formed of rows 2062 and columns 2064 of electrodes. A controller is arranged to drive a current through a single row of the touch sensor layer 2060 and then to scan (in order) each column of the touch sensor layer 2060 for an induced current; this process is repeated for each row. The current induced in a given column will depend on whether a user (e.g. a user's finger) is near the row being driven. With a mutual capacitance sensor, the capacitance value at each intersection can be evaluated separately so that the sensing of multiple touch points is possible. Other capacitive sensors, such as self-capacitance sensors, may also be used -for some of these sensors, detection of multiple touch points may not be possible. A more detailed view of a capacitive touch sensor is described below with reference to Figures 8a -Sc. More generally, any grid of sensor elements may be used to detect a touch input, e.g. a grid of pressure sensors or optical elements may be used.

In this embodiment, there is provided a capacitive sensor with rows and columns arranged in a diamond formation as shown in Figure 6a, where the separations between the rows 2062 and the columns 2064 of the capacitive sensor are at an angle compared to the edges of the keyboard 2000. Other arrangements may be used, e.g. a comb arrangement where the separations between the rows and columns of electrodes are parallel to the edges of the keyboard 2000.

In order to sense the presence of an object, the touch sensor layer 2060 may be located near the top of the keyboard, e.g. immediately beneath the keypress mechanism 2040 or the transmittal mechanism 2030. Proximity to the keycaps 2050 enables simple sensing of a users touch on the keycaps 2050. In order to amplify the capacitive effect of the user's touch on the keycaps 2050, there may be provided a conductive material on the keycaps 2050 or an electrical connection between the keycaps 2050 and the touch sensor layer 2060. The use of a conductive material may be particularly beneficial when the touch sensor layer 2060 is distant from the keys 2002.

Typically, the touch sensor layer 2060 is located above the keypress sensor layer 2020 and below the level of the keypress mechanisms 2040; this arrangement places the touch sensor layer 2060 close enough to the top of the keyboard 2000 to detect the touch of a user on the keycaps 2050 of the keyboard 2000 while enabling the touch sensor layer 2060 to be provided as a single plate (since the touch sensor layer 2060 does not move due to a movement of the keys 2002. More generally, the touch sensor layer 2060 is typically located below the layer of the keypress mechanisms 2040 so as to allow provision of the touch sensor layer 2060 as a single plate.

In some embodiments, the touch sensor layer 2060 comprises holes that enable the passage of the hook mounts 2012 of the base plate 2010; this enables the hook mounts 2012 (or a component that can be secured to the hook mounts 2012) to pass through the touch sensor layer 2060 so that the keypress mechanisms 2040 can be secured to the hook mounts 2012.

Where the touch sensor layer 2060 is provided above the keypress sensor layer 2020, the keypress sensor layer 2020 may be arranged to detect the depression of the transmittal mechanisms 2030 through the touch sensor layer 2060. As an example, the depression of the transmittal mechanisms 2030 may apply a pressure to the touch sensor layer 2060 that results in the depression of the portion of the touch sensor layer 2060 directly beneath the pressed key; -12 -this depression of the touch sensor layer 2060 is detected by the sensor 2022 of the keypress sensor layer 2020.

In some embodiments, there are provided holes in the touch sensor layer 2060 to enable the transmittal mechanisms 2030 (or a part of the transmittal mechanisms 2030) to pass through the touch sensor layer 2060 so as to actuate the sensors 2022 of the keypress sensor layer 2020.

The holes in the touch sensor layer 2060 are typically arranged so that they do not overlap with any intersections of the rows 2062 and columns 2064 of electrodes of the touch sensor layer 2060. For example, the touch sensor layer 2060 may comprise one or more holes located entirely between the diagonal separation lines of electrodes of the touch sensor layer 2060. This is described in more detail in reference to Figures 8a -8c.

Referring to Figure 6b, where the touch sensor layer 2060 is provided, a protective layer 2070 may be provided to protect the touch sensor layer 2060 from dust and moisture. The protective layer 2070 is typically made of a plastic material and/or a thin film.

The protective layer 2070 is typically located above the touch sensor layer 2060. Like the touch sensor layer 2060, the protective layer 2070 may comprise holes so as to allow the passage of transmittal mechanisms 2030. The transmittal mechanisms 2030 may then be mounted on the protective layer 2070. In this situation, the touch sensor layer 2060 and the protective layer 2070 may be considered to be a single combined touch sensor/touch sensor layer (so that the transmittal mechanisms 2030 being mounted on the protective layer 2070 effectively involves the transmittal mechanisms 2030 being mounted on a touch sensor).

More generally, each layer of the keyboard 2000, and/or each layer between the base layer 2010 and the keypress mechanisms 2040 may comprise holes. Typically, each layer comprises concentric holes so that the hook mounts 2012 (or a light from a backlight) can pass through each layer.

In some embodiments, a backlight is provided so that a user can easily use the keyboard 2000 without an external light source. In these embodiments, there is typically a light guide layer (not shown) included in the keyboard, which light guide layer directs the lights to pass through the keycaps 2050 of the keyboard 2000. In these embodiments, the protective layer 2070 may be transparent or comprise transparent portions.

Typically, the light guide layer and/or the optical elements that provide light for the backlight are placed either at the base of the keyboard (beneath the base plate 2010); above the touch sensor layer 2060; in or on the touch sensor layer 2060 (e.g. so that the backlight is integrated with the touch sensor/touch sensor layer 2060); or above the protective layer 2070.

Each layer is typically secured to the other layers with an adhesive layer, e.g. a layer of glue or an adhesive tape (e.g. a double sided adhesive tape). Securing the layers together ensures that the rigid base plate 2010 is able to provide rigidity to the remainder of the layers.

The hook mounts 2012 are arranged to pass through the touch sensor layer 2060 and the protective layer 2070 in order to secure the keypress mechanisms 2040; this also provides rigidity to the intervening layers.

-13 -While it will be appreciated that the layers of the keyboard 2000 may be arranged in any order -and any combination of layers may be provided and/or removed -a preferred arrangement of the layers is as follows: 1. (optionally) The light guide layer (not shown).

2. The base plate 2010.

3. (optionally) A layer of adhesive.

4. The keypress sensor layer 2020.

5. (optionally) A layer of adhesive.

6. The touch sensor layer 2060.

7. (optionally) A layer of adhesive.

8. (optionally) The protective layer 2070.

9. The transmittal mechanisms 2030.

10. The keypress mechanisms 2040.

11. The keycaps 2050.

As has been described above, typically the base layer 2010 comprises hook mounts 2012 that pass through each of the layers between the base plate 2010 and the keypress mechanisms 2040 (including the touch sensor layer 2060).

As has been described above, the transmittal mechanisms 2030 may be arranged to pass through the other layers so as to be able to actuate the sensors 2022 of the keypress sensor layer 2020.

Furthermore, the transmittal mechanisms 2030 may pass through, or be located internally to, the keypress mechanisms 2040, so that the keypress mechanisms 2040 are effectively adjacent to the protective layer 2070.

Typically, the transmittal mechanisms 2030 (e.g. silicone domes) are mounted on the touch sensor layer 2060, where the depression of the transmittal mechanism 2030 may result in a part of the transmittal mechanism 2030 passing through a hole of the touch sensor layer 2060.

Typically, a ground layer is located between the keypress sensor layer 2020 and the touch sensor layer 2060; for example, directly above the keypress sensor layer 2020. This ground layer is arranged to prevent interference between the keypress sensor layer 2020 and the touch sensor layer 2060.

There is disclosed herein a method of detecting keypresses using the touch sensor layer 2060.

In these embodiments, the keyboard 2000 may be provided without the keypress sensor layer 2020.

In these embodiments, and other embodiments, the keyboard 2000 may be provided without the base plate 2010. Where the keyboard 2000 is provided without the base plate 2010 in particular (but also where the keyboard 2000 has the base plate 2010), the touch sensor layer 2060 may be provided as a rigid layer that provides rigidity to the keyboard 2000; for example, the touch sensor layer 2060 may comprise an FR4 material.

In some embodiments, the keyboard 2000 comprises (optionally, only): 1 A touch sensor layer 2060, which may also be used to detect keypresses, as is described further below.

-14 - 2. Keycaps 2050.

In such embodiments, the keycaps 2050 may perform certain functions of the transmittal mechanisms 2030 and the protective layer 2070 (e.g. the operation of the touch sensors). Typically, such embodiments further comprise keypress mechanisms 2040 between the touch sensor layer 2060 and the keycaps 2050. As is described further below, these keypress mechanisms 2040 may also provide some of the functionality that is conventionally provided by the transmittal mechanisms 2030.

In these embodiments in particular, the keycaps 2050 may each be associated with (e.g. comprise) a conductive and/or metal element. In particular, there may be a metal coating arranged on or in the keycaps (e.g. embedded in layers of silicon). In a preferred embodiment, there are metal elements (e.g. embedded in layers of silicon) located on each corner of some or all of the keycaps 2050. This aids in the detection of a keypress by the keypress sensor layer 2020 (where a keypress sensor layer is used) and/or the touch sensor layer 2060 (as is described further below).

Where a keypress sensor layer 2020 is provided, this may be provided in combination with the touch sensor layer 2060 (e.g. in a combined printed circuit board (PCB) layer).

As has been explained with reference to Figure 5a, keypresses can be detected using a keypress sensor layer that contains a number of sensors to detect the pressing of a key.

An aspect of the present disclosure relates to instead (or additionally) determining keypresses using the touch sensor layer 2060. In particular, where the touch sensor layer 2060 comprises a capacitive sensor, the transmittal mechanism 2030 may be arranged so that pressing the key 2002 results in a change in the local electric field near the touch sensor layer 2060.

As shown in Figure 9, one way of achieving this is by attaching a coating 2034, e.g. a metal coating, to the transmittal mechanisms 2030 and/or the base of the keys 2002 so that when a key is pressed a corresponding coating approaches and/or contacts an electrode of the touch sensor layer 2060. This presence of the coating 2034 results in a determinable alteration of the local electric field beneath the pressed key. This alteration can be detected using the touch sensor layer 2060.

In various embodiments, the coating 2034 comprises one or more of: a metal coating, an electrically conductive coating, a metal oxide semiconductor coating, and an electrically insulating coating. Typically, the coating 2034 is arranged to cause a greater alteration to the local electric filed than the presence of a user's finger alone (e.g. an alteration at least twice the alteration due to a user's finger).

The coating 2034 may be located on any component that moves when the keycap 2050 is depressed. Typically, the coating is located on the keycap 2050 (e.g. on the underside of the keycap) and/or on the transmittal mechanism 2030 (e.g. on the exterior of the silicone dome 2032 or on the interior of the silicone dome 2032). In other words, the coating 2034 is arranged so that the coating 2034 is moved when the keycap 2050 is pressed.

In order to increase the sensitivity of the touch sensor layer 2060 and improve the detection of keypresses, in some embodiments the touch sensor layer 2060 is arranged so that the coating 2034 on the transmittal mechanism 2030 is located above an intersection of the rows and columns -15 -of the touch sensor layer 2060. This is illustrated in Figure 9, which shows an exemplary contact point 2066 (or a nearest approach point) on the touch sensor layer 2060. This contact point 2066 is arranged to be located beneath the coating 2034 of a key of the keyboard 2000 so that when the key is depressed, the coating 2034 approaches the contact point 2066.

In some embodiments, the transmittal mechanism 2030 and/or the coating 2034 is located above the centre of a sensor of the touch sensor layer 2060 (e.g. to be at the centre of an electrode). In some embodiments, the transmittal mechanism and/or the coating of one or more keys is arranged to be at the intersection of a row of electrodes and a column of electrodes (e.g. the point at which the necks of two electrodes overlap).

By using the touch sensor layer 2060 to detect keypresses, the keyboard 2000 can be provided without the (separate) keypress sensor layer 2020. This enables the provision of a thin keyboard that is useable both for typing and as a touchpad. This also enables the provision of the touch sensor layer 2060 without holes to enable the passage of the transmittal mechanisms 2030. The lack of a need to provide holes in the touch sensor layer 2060 can simplify manufacture of the touch sensor layer 2060.

In some embodiments, and in particular in embodiments where keypresses are detected using the touch sensor layer 2060, the touch sensor layer 2060 comprises optical elements (e.g. LEDs) arranged to provide a backlight. Where keypresses are detected using the touch sensor layer 2060, holes in the touch sensor layer 2060 for the transmittal mechanisms 2030 are not required; the optical elements may then replace these holes (e.g. so that the optical elements do not overlap with any edges of touch sensor elements). More generally, optical elements may be located on the touch sensor layer 2060 based on the same sets of conditions for the placing of the holes. There may be provided a touch sensor layer 2060 that comprises both holes and optical elements, wherein the locating of the optical elements and the holes is based on the same sets of conditions.

While the detection of a keypress has been described with reference to a capacitive touch sensor, it will be appreciated that such detection is possible with other sensing mechanisms. As an example, a pressure sensor may be used to detect both touches and keypresses, where a light pressure placed on the keys 2002 is indicative of a user providing a touch/pointer input and a heavy pressure placed on the keys 2002 (e.g. a keypress) is indicative of a keystroke input.

Exemplary keyboard constructions where the touch sensor layer 2060 is used to detect keypresses are as follows: 1 The base plate 2010.

2 (optionally) A layer of adhesive.

3 The touch sensor layer 2060.

4 (optionally) The protective layer 2070.

The transmittal mechanism 2030.

6 The keypress mechanisms 2040.

7 The keycaps 2050. and

1 The base plate 2010.

2 (optionally) A layer of adhesive.

-16 - 3 The touch sensor layer 2060.

4 (optionally) The protective layer 2070.

The transmittal mechanism 2030.

6 The keypress mechanism mounting layer (not shown).

7 The keypress mechanisms 2040.

8. The keycaps 2050.

Touch sensor layer The touch sensor layer 2060 may be any layer that is capable of detecting the position of the finger of a user. The touch sensor layer 2060 may comprise optical sensors, pressure sensors, self-capacitive sensors, and/or mutual capacitance sensors. While the touch sensor layer 2060 is typically described as sensing a touch on the keys of the keyboard 2000, the touch sensor layer may also be arranged to sense an object proximate to the touch sensor layer 2060, where this object may move above the keys 2002 of the keyboard 2000.

As shown in Figure 6a and, in more detail in Figure 7, the touch sensor layer 2060 typically comprises a matrix of electrodes that is used to provide a projected capacitive keyboard.

The 'rows' 2062 of electrodes form a transmitting channel, while the 'columns' 2064 of electrodes form a receiving channel. In order to detect a touch, a control unit (not shown) sends a signal sequentially to each of the rows 2062 (so that at any one time only one electrode row is being 'driven'). This results in a signal being induced in the receiving channels/columns 2064. The touch of a user, or the proximity of the coating 2034, alters the local electric field in the vicinity of the electrodes and thereby alters the signal that is induced in each receiving channel/column. For each pair of rows 2062 and columns 2064 there will be a single intersection; therefore, by detecting an alteration in the local electric field for a receiving column based on a driven row, it is possible to detect the precise location of a touch or a keypress.

It will be appreciated other arrangements may be used, e.g. where the columns form the transmitting channel of the touch sensor layer 2060 and the rows form the receiving channel of the touch sensor layer 2060.

In order to detect the alteration in the local electric field, it is necessary to calibrate the touch sensor layer 2060 in order to determine a baseline for the induction in each receiving channel (for each transmitting channel). Differences from this baseline measurement can then be detected. In order to calibrate the touch sensor layer 2060, the signal induced in each column 2064 by a signal being sent to each row 2062 is measured in the absence of a user.

It will be appreciated that a change in the local electric field can be caused simply by proximity to the touch sensor layer 2060; it is not necessary for the user or the coating 2034 to directly impact the touch sensor layer 2060.

In order to distinguish between a keypress and the touch of a user, a control unit which receives signals from the touch sensor layer 2060 may: Determine a direction and/or location of movement -typically, the keys will move substantially perpendicular to the touch sensor layer 2060, so that the detection of a substantial parallel movement is useable to identify a user touch and the detection of a substantial perpendicular movement is useable to identify a keypress. Similarly, the keys 2002 will typically be -17 -restrained so that each key has a fixed range and location of motion; in contrast a movement across the keyboard (e.g. a user's touch) is unrestrained. Therefore, a keypress may be identified by identifying a specific location/direction of movement.

- Determine a magnitude of a change in the local electric field (e.g. by measuring a current induced in the receiving channels) -typically, the coating 2034 will cause a different (e.g. greater) change in the local electric field than a human finger.

- Determine a rate and/or duration of a change in the local electric field -typically a key is pressed and then released so that the duration of the change in the local electric field may be shorter for a key press than for a finger movement. Similarly, the rate of change of the local electric field may be higher for a key press. Additionally, the depression of a key will result in a change that increases to a peak. The release of a key will cause a decrease in a similar way. This may not be true for a user's touch.

In some embodiments, the coating 2034 is not provided and the touch sensor layer 2060 is nevertheless used to determine a keypress. Such detection may occur based on the considerations above; in particular a movement of a finger directly towards the touch sensor 2060 (and below the raised level of the keys 2002) may be interpreted as a keypress, while a movement perpendicular to the touch sensor layer 2060 may be interpreted as a touch gesture.

In some embodiments, the control unit of the keyboard 2000 processes signals from the touch sensor layer 2060 in dependence on an input mode of the keyboard 2000. The keyboard 2000 may have a plurality of input modes that can be selected by a user, including a keypress input mode and a pointer input mode. In the keypress input mode, the controller of the touch sensor layer 2060 may expect keypresses, and so detect an isolated capacitive change indicative of a keypress as a keypress. In the pointer input mode, the controller of the touch sensor layer 2060 may expect a user's touch and so may ignore such an isolated change in capacitance, or interpret this change as a touch gesture instead of a keypress.

In some embodiments, the control unit detects keypresses even in the pointer input mode and uses such keypresses as a signal to change to a keypress input mode. Alternatively, the output of pressing a key may differ between the input modes (e.g. the space bar may enter a space when the keyboard is in the keypress input mode and may simulate a mouseclick when the keyboard is in the touchpad input mode).

Exemplary keyboard input modes, and exemplary methods for switching between these input modes, are described in more depth below as well as in W02019237173 ("INPUT DEVICE, SIGNAL PROCESSING UNIT THERETO, AND METHOD TO CONTROL THE INPUT DEVICE").

Touch sensor modes As described above, in order to detect an event using the touch sensor (e.g. a touch or a keypress) a control unit sends a drive signal sequentially to each of the rows 2062 and monitors a resultant signal induced in the columns 2064 (or vice versa). In particular, this induced signal can be processed to detect a touch event occurring above the touch sensor layer 2060 and/or a keypress event.

In a basic example, the driving of row x results in a signal being induced in column y. The baseline signal induced in column y due to the driving of row x (e.g. the signal where there is no object -18 -above the intersection of row x or column y) can be determined in a calibration process by measuring the signal induced in column y when no object is present. A deviation from this baseline signal can be then used to determine the presence of an object in the vicinity of the intersection of row x and column y. By driving each row and then detecting (for each row) the resultant signal induced in each column, the presence of an object near any intersection of rows and columns can be detected.

More specifically, the control unit drives the rows of the touch sensor layer 2060 consecutively at a certain drive rate, and then scans all of the columns 2064 to detect a corresponding induced signal. Typically, each column is scanned simultaneously.

The control unit typically receives signals continuously from each of the columns of the touch sensor. In order to detect a touch event and/or a keypress event, the signal received from each column is processed (e.g. integrated) over a certain scanning period. For example, each signal may be integrated over a period of lms to detect whether there has been a touch or a keypress near this column in the 1ms period.

The scanning may also be associated with a scanning rate associated with a number of scanning frames that are processed for a given time period. This scanning rate is typically the inverse of the scanning period so that a scanning pattern with a long scanning period has a low scanning rate.

In a practical example, a block of 1 second of time is divided into separate scanning frames. The division of this block may be based on a high scanning period and a low scanning rate (e.g. the block may be divided into twenty 50ms frames so that the scanning period is 50ms and the scanning rate is 20Hz). Equally, the division of this block may be based on a low scanning period and a high scanning rate (e.g. the block may be divided into one thousand frames of 1ms so that the scanning period is 1ms and the scanning rate is 1000Hz). It will be appreciated that in practice frames are processed rapidly and/or in real time. So in practice, instead of receiving a block of 1 second of time and then dividing this block, the control unit will regularly integrate the previous 50ms or lms of a signal induced in a column of the touch sensor.

In some embodiments, blocks of time are divided into overlapping frames, e.g. a block may be divided into a first frame from Oms -5ms, a second frame from lms -6ms and so on. However, typically, non-overlapping frames are used to avoid the double detection of a keypress or touch event (with overlapping frames, if a keypress occurs at 2ms it may be detected in both the first frame and the second frame and therefore registered twice).

While this description primarily describes a drive signal being applied to the rows 2062 of the touch sensor layer 2060, and the control unit then scanning the columns 2064 of the touch sensor to detect a touch event and/or a keypress event, it will be appreciated that the drive signal could equally be applied to the columns of the touch sensor with the scanning occurring at the rows of the touch sensor. More generally, the touch signal comprises a transmitting channel (one of the rows and the columns) and a receiving channel (the other of the rows and the columns), where a drive signal is applied consecutively to the transmitting channels and the control unit scans the receiving channels to detect a touch event and/or a keypress event.

-19 -As explained above, the columns 2064 may be scanned based on different scanning periods and/or rates.

The use of a high scanning rate and/or a low scanning period enables the touch sensor to detect rapid events more accurately (since each scanning frame relates to only a short period, so two consecutive events are unlikely to fall into the same scanning frame). However, the use of a high scanning rate reduces the time available for any event to be processed. Therefore, if a high scanning rate is used, low magnitude events are more likely to be missed (low magnitude events can be lost in background noise if the induced signals are integrated over a short period.

In this regard, touch events typically have a low signal to noise ratio (SNR) as compared to keypress events. This is partly because touch events tend to occur on the surface of the keys when the keycaps are in a raised position (and so the user's fingers are far from the touch sensor). Conversely, keypress events tend to have a comparatively higher signal to noise ratio, not least because as a key is depressed the user's fingers and a coating associated with the key (if a coating is provided) approach the touch sensor layer 2060. As described above, the coating of each key is typically arranged to approach an intersection of the rows 2062 and columns 2064 of the touch sensor layer 2060; this further improves the signal to noise ratio for keypresses.

However, while keypresses are typically associated with signals of high magnitude, keypresses are also short events; therefore, a keypress event typically results in a short, sharp, variation in a signal induced in a column of the touch sensor. Such short events may be missed by a touch sensor that uses a low scanning rate, especially where multiple keypress events occur in a short amount of time. In particular, where a single key is pressed multiple times and a long scanning period is used, these multiple keypresses may fall within the same scanning frame and so only a single keypress may be detected following the integration of a scanning frame.

Due to the low SNR of touch events, in order to accurately process touch events, the touch sensor layer 2060 may be arranged to operate based on a high scanning period and/or a low scanning rate. Specifically, the control unit may be arranged to use a scanning period of at least 2 milliseconds (ms), at least 5ms and/or at least 10ms and/or the control unit may be arranged to use a scanning rate of no more than 250Hz, no more than 200Hz, and/or no more than 100Hz. With these scanning periods and scanning rates, each column of the touch sensor is scanned for a sufficient time to enable accurate detection of touch events.

Each column may be scanned for a single substantial time period. Equally, each column could be scanned for a plurality of shorter component periods (still based on the low rate scanning signal), For example, instead of being scanned from Oms -5ms, a column may be scanned from Oms -2.4ms and then 2.6ms -5ms with the plurality of shorter component periods being processed together to enable accurate detection of a touch. The use of a long scanning period thus also discloses the use of a long scanning period that comprises a plurality of shorter, optionally nonconsecutive, component scanning periods.

Since keypresses are often associated with fast events, in order to accurately and quickly detect groups of keypresses, the touch sensor layer 2060 may be arranged to operate based on a high scanning rate and/or a low scanning period. For example, the control unit may be arranged to use a scanning rate of at least 250Hz, at least 500Hz, at least 750Hz, and/or at least 1000Hz and/or the control unit may be arranged to use a scanning period of no more than 1ms, no more than -20 - 1.3ms, no more than 2ms, and/or no more than 2.5ms. Since keypresses are typically associated with a high signal to noise ratio, the use of a high scanning rate and a low scanning period does not preclude the control unit from accurately detecting keypresses. The signal to noise ratio associated with keypress events can also be increased by the use of coatings associated with the keys to further ensure high accuracy with a high scanning rate.

Referring to Figure 10, there is shown a simplified illustrative example of a signal in a column that has: a constant background noise of magnitude 1, a touch event of magnitude 2 from t=4ms - 14ms, two keyboard press events of magnitude 5 from t=16ms -17ms and t=19ms -20ms.

Using a scanning period of 10ms would result in the two keypresses falling into the 10ms -20ms block; therefore, only one of these keypresses would be detected. However, using a shorter scanning period might result in the relatively low magnitude touch event being missed.

Therefore, the present disclosure relates to a touch sensor that is arranged to operate based on a first scanning period and/or scanning rate and a second scanning period and/or scanning rate, where the first and second scanning periods/rates are different. Using the example of Figure 10, a scanning period of 10ms would be suitable to detect the touch event and a scanning period of 1ms would be suitable to detect both keypresses. By providing a touch sensor that can operate with both of these scanning periods, all types of events can be accurately detected.

It will be appreciated that Figure 10 is only a very simple illustrative example and that in practice the periods and comparative magnitudes of these events may differ.

Typically, to enable accurate detection of both touch events and keypress events the keyboard 2000 is arranged to operate in one or more of the following scanning modes: - A touch scanning mode. The touch scanning mode typically uses a comparatively high scanning period (e.g. 5ms -10ms) and/or a comparatively low scanning rate (e.g. 100 -200Hz). This mode is suitable for detecting and interpreting touches on the keys of the keyboard.

- A keypress scanning mode. The keypress scanning mode typically uses an intermediate scanning period (e.g. 2ms -5ms) and/or an intermediate scanning rate (e.g. 200 -500Hz). This mode is suitable for precisely detecting key coordinates in order to accurately classify keypresses.

-A keypress detection mode. The keypress detection mode typically uses a comparatively low scanning period (e.g. 1ms -2ms) and/or a comparatively high scanning rate (e.g. 500 -1000Hz). This mode can be used to detect the depression of a key of a keyboard.

In some embodiments, the touch sensor layer 2060 is arranged to operate in each of a self capacitance mode and a mutual capacitance mode. The mutual capacitance mode operates as described above, where a driving signal is provided to the rows of the touch sensor and this driving signal induces a signal in the columns of the touch sensor (or vice versa), which induced signal can be processed to identify a touch or keypress. In the self-capacitance mode, the rows and columns of the touch sensor operate independently, with a signal being driven through each of the rows and the columns. The location of a touch can then be detected by a local change in capacitance in each of the rows and the columns (with this change in capacitance being caused by the movement of a coating and/or a user's finger). Operation in a self capacitance mode -21 -provides a stronger signal than operation in a mutual-capacitance mode and enables rapid detection of a touch, since the driving signal may be provided substantially continuously and the scanning rate may be very high (e.g. in excess of 1000Hz). However, the use of the self-capacitance mode can prevent the accurate resolution of multiple touches due to the occurrence of 'ghost' events.

In some embodiments, the keypress detection mode is a self capacitance mode, which is useable to rapidly pick up keypresses and provide approximate locations of the keypresses, and the keypress scanning mode is a mutual capacitance mode, which is useable to accurately detect keypresses at multiple locations. The keypress scanning mode may be activated in dependence on the detection of a keypress in the keypress detection mode, so that the keypress detection mode rapidly detects the occurrence of a keypress and the keypress scanning mode thereafter accurately detects the location of the keypress and/or of following keypresses.

Not least due to the offset between the rows of certain standard keyboard layouts (e.g. the ANSI keyboard layout), 'ghost' events can typically be detected and ignored so that a self capacitance mode may be used to accurately resolve keypresses. In this regard, ghost events occur where there are two or more touches on the touch sensor; for example, a first touch at an intersection of an mth row and a nth column and a second touch at an intersection of an (m+1)th row and an (n+3)th column. In this situation, the control unit only identifies that touches have occurred on the mth and (m+1)th row and on the nth and (n+3)th column; therefore, alongside the real events, ghost events will be detected at the intersections of the (m+1)th row and the nth column and at the intersection the mth row and (n+3)th column.

According to the present disclosure, the control unit of the keyboard may process signals to remove ghost touches. Since the keys are in a fixed arrangement, the expected locations of possible keypress are known to a high degree of accuracy (e.g. the keys may be arranged so that keypresses are expected to be detected directly above intersections of the rows and columns of the touch sensor). Therefore, keypress events that are detected in unexpected locations (e.g. between intersections of the rows and columns of the touch sensor) may be determined to be ghost events and may be discounted by the control unit. In practice, due to the offset between rows of standard keyboards, the locations of ghost events are likely to be away from the locations of potential keypresses, so that accurate detection of ghost events is typically possible.

Therefore, the keyboard may be provided with only two modes, in particular a self capacitance keypress detection mode and a mutual capacitance touch detection mode.

In some embodiments, the detection of ghost events may not be possible for all events (e.g. there may be some situations in which a potential ghost event occurs at the location of a potential keypress). Therefore, the keyboard may be arranged to operate in a self capacitance scanning mode when accurate determination of a ghost event is possible (e.g. because the potential ghost event occurs between intersections of the rows and columns of the touch sensor) and to switch into in a mutual capacitance keypress scanning mode when accurate determination of a ghost event is not possible.

It will be appreciated that in order to detect keypresses the keyboard 2000 may use only a single one of the keypress detection mode and the keypress scanning mode. In particular, in some embodiments the keypress detection mode is not provided.

-22 -The scanning mode of the keyboard 2000 may be dependent on an input of a user and/or on a recent event. For example, the user may be able to switch the keyboard between the touch scanning mode and the keypress scanning mode.

Typically, the keyboard 2000 is arranged to default to the touch scanning mode, where the detection of a keypress (e.g. the detection of a signal variation of large magnitude in a column of the touch sensor) results in the keyboard switching into the keypress detection mode or the keypress scanning mode. This keypress detection mode or keypress scanning mode can then be used to detect a rapid series of keypresses. In this regard, when a user is typing a word or sentence, there is often a first keypress that is followed by a rapid series of further keypresses.

The scanning rate of the touch scanning mode is typically sufficient to accurately detect the first keypress, but in order to accurately resolve following keypresses it may be beneficial to use a higher scanning rate, such as that of the keypress detection or keypress scanning mode.

Referring to the example of Figure 10, the keyboard 2000 may operate in the touch scanning mode by default, so that in a first touch scanning frame from Oms -10ms the keyboard detects the touch event starting at 4ms. In a second scanning frame from 10ms -20ms, the keyboard detects the continuing touch event as well as detecting at least one keypress event. The keyboard is typically able to distinguish between touch events and keypress events, e.g. based on a signal magnitude. When a keypress is detected, the keyboard typically switches into the keypress scanning mode.

Continuing with the example of Figure 10, the keyboard 2000 may switch into the scanning mode following the second touch scanning frame (e.g. at P2Oms). However, in order to ensure that no keypresses are missed, typically the keypress scanning mode is arranged to interrupt and/or overlap the touch scanning mode. For example, the keyboard may reprocess the signal from 10ms -20ms using the keyboard scanning mode (and the keyboard may comprise a cache that stores previous signal values to enable this reprocessing). Therefore, following the detection of the keypress the keyboard may process (e.g. integrate) the signal from 10ms -20ms using five separate frames of 2ms each. Using such frames, the keyboard can identify that there are two keypresses during this period.

More generally, the keyboard may be arranged to process the same portion of a signal based on 30 each of a first mode and a second mode, where the processing based on the second mode is dependent on a keypress event being detected using the first mode.

To avoid duplication of events, the keyboard may be arranged to output only touch event data in the touch scanning mode and to output only keypress event data in the keypress scanning and/or keypress detection modes. Therefore, the processing of this signal may involve: a) Using a touch scanning mode to integrate the signal from 0-10ms.

b) Detecting and outputting the touch event starting at 4ms.

c) Using a touch scanning mode to integrate the signal from 10-20ms.

d) Detecting (but not outputting) a keypress event (based on a large magnitude of the integrated signal).

e) Using a keypress scanning mode to integrate a frame from 10-12ms.

f) Using a keypress scanning mode to integrate a frame from 12 -14ms.

g) Using a keypress scanning mode to integrate a frame from 14-16ms.

-23 -h) Using a keypress scanning mode to integrate a frame from 16-18ms.

i) Detecting and outputting the keypress event at 16ms.

j) Using a keypress scanning mode to consider a frame from 18-20ms.

k) Detecting and outputting the keypress event at 19ms.

With the above example, the continuation of the touch event from 10ms -14ms is not output by the keyboard. In practice, touch events and keypress events are likely to be separated by a more substantial period of time (due to the limited speed of the hands of a user) and so the interruption of the touch scanning mode by the keypress scanning mode is normally not problematic and normally does not result in the neglecting of a touch signal.

In some embodiments, the keyboard is arranged to process the signal based on the touch detection mode in dependence on the time of a detected keypress. With the above example, the keyboard may identify that there are no keypresses before 16ms and thereafter use a touch detection mode to search for touches in the period from 10-16ms.

An implementation of the above-described scanning modes is now described with reference to the flowcharts of Figures 11 a and 11 b.

Referring to Figure 10a, the keyboard 2000 typically starts in a touch scanning mode.

The keyboard 2000 then continuously/regularly determines 102 whether a keypress has occurred (e.g. by detecting a large variation in a signal in the columns 2064 of the touch sensor layer 2060 while in the touch scanning mode).

If a keypress has occurred, the keyboard 2000 switches into 103 a keypress scanning mode. If a keypress has not occurred recently, then the keyboard stays in 101 the touch scanning mode. Switching the scanning mode may involve reprocessing of a preceding period of the signal as described above.

When the keyboard 200 is in the keypress scanning mode, the keyboard continues to determine whether a keypress has occurred recently. If a keypress has occurred recently, the keyboard 2000 stays in 103 the keypress scanning mode. If a keypress has not occurred recently, then the keyboard switches into 101 the touch scanning mode. Switching the scanning mode may involve reprocessing of a preceding period of the signal as described above.

In this context, a keypress having been detected recently may, for example, comprise a keypress having been detected in a previous scanning frame and/or a previous time period (e.g. the previous 10ms).

Referring to Figure 11b, an implementation that uses three scanning rates/scanning modes is described.

In a first step 111, the keyboard 2000 (e.g. the control unit of the keyboard) uses a first scanning period with the touch sensor. This first scanning rate may be associated with the keyboard operating in the touch scanning mode.

In a second step 112, the keyboard 2000 uses a third scanning period with the touch sensor. This third scanning period may be associated with the keyboard operating in the keypress detection mode.

-24 -The first step 111 and the second step 112 may involve interrupting the touch scanning mode with the keypress detection mode. So the touch scanning mode may be used to process touch scanning frames between, for example, 0.1ms -1ms, 1.1ms -2ms, 2.1ms -3ms, and, so on with the keypress detection mode being used between Oms -0.1ms, 1ms -1.1ms, 2ms -2.1ms, and so on. The signals across each of the component touch scanning frames may be combined and integrated. This alternating operation provides a sufficient total touch scanning period to accurately detect touch events with the touch scanning mode while also providing rapid detection of keypresses using the keypress detection mode. In practice, the touch scanning mode is typically interrupted more regularly but for shorter periods of time (since only a very short period of time is required to detect a high SNR keypress event, especially if the keyboard detection mode is a self capacitance mode).

In a third step 113, the keyboard 2000 (e.g. the control unit of the keyboard) determines whether a keypress has occurred recently.

If a keypress has not occurred, the method returns to the first step 111.

If a keypress has occurred recently, then in a fourth step 114, the keyboard 2000 uses a second scanning period with the touch sensor. This second scanning period may be associated with the keyboard operating in the keypress scanning mode.

Following the fourth step 114, the method returns to the third step 113 and the keyboard 2000 again determines whether a keypress has occurred recently.

Typically, the detection of a keypress activates the keypress scanning mode. For example, the detection of a keypress in the keypress detection mode may active the keypress scanning mode for a short period (e.g. a few microseconds) following the detection.

Typically, the absence of a keypress event for a certain period of time (e.g. the lack of detection of a signal of large magnitude in a column of the touch sensor layer 2060 for a certain period of time) when the keyboard 2000 is in the keypress detection mode or the keypress scanning mode results in the keyboard switching to the touch scanning mode. The keyboard is typically arranged to switch to the touch scanning mode if no keypress is detected within a certain time period, where this certain period may be no more than 1 second, no more than 100ms, and/or no more than 10ms (e.g. the keyboard may be arranged to switch into the touch scanning mode if no keypress events are detected for a period of 10ms) and/or where this certain time period may be at least 1ms, at least 10ms, and/or at least 100ms.

The above-described features result in a keyboard 2000 where touch events and keypress events can be accurately and rapidly identified while a user is still able to alternately perform keypress events and touch events without a noticeable intervening period.

In some embodiments, the keyboard 2000 is arranged to operate alternately in the touch scanning mode and keypress detection mode or keypress scanning mode. That is, the touch scanning mode is arranged to be periodically interrupted by the keypress scanning mode or the keypress detection mode. For example, the low rate touch scanning mode signal may be used for a period of lms, before the high rate keypress detection mode signal is used for a period of 0.1ms, and so on.

-25 -In some embodiments, the touch scanning mode and the keypress detection mode or keypress scanning mode are arranged to be used for different columns of the touch sensor layer 2060. For example, the touch scanning mode may be used for a first set of columns of the touch sensor and the keyboard scanning mode may be used for a second set of columns of the touch sensor.

Equally, the touch scanning mode may be used for a first set of columns of the touch sensor while the keyboard scanning mode is used for the whole of the touch sensor so that the modes are used simultaneously for the first set of columns (and a method of simultaneous operation of modes is described below).

These sets of columns may then use alternating operation; for example, the control unit may alternate between the touch scanning mode and the keypress scanning mode for the first set of columns and between the keypress scanning mode and the touch scanning mode for the second set of columns. These sets of columns may be arranged so that each set of columns comprises columns distributed across the keyboard (e.g. the first set may comprise first, third, fifth, etc. columns and the second set may comprise second, fourth, sixth etc. columns). This enables detection of both touch events and keypress events across the entirety of the keyboard 2000, albeit typically with reduced accuracy compared to where a single mode is used for all the columns.

In practice, this alternating operation may comprise the control unit using a combined scanning frame (that is repeated continuously). This combined scanning frame may be formed of a single touch detection frame (that contains a low rate scanning signal) and one or more keypress detection and/or scanning frames (that contain a high rate scanning signal). For example, a combined scanning frame may be used from Oms -7.5ms that comprises a single touch scanning frame from Oms -5ms Of the touch scanning rate is 200Hz) and then two keypress scanning frames from 5ms -7.5ms (if the keypress scanning rate is 500Hz). Such a combined scanning frame may then be repeated from 7.5ms -15ms, and so on.

In some embodiments, the keyboard 2000 is arranged to operate simultaneously in the touch scanning mode and the keypress detection mode or keypress scanning mode Again using the example of Figure 10, the control unit may use the touch scanning mode to process the signal over a single 5ms frame from Oms -5ms. The control unit may also use the keypress scanning mode to process the signal over five lms frames of the same period (e.g. from Oms -lms, lms -2ms, and so on). This enables the accurate detection of touches using a touch scanning mode with a high scanning period/low scanning rate and also accurate detection of keypresses based on a keypress scanning mode with a lower period/higher rate.

As has been described above, the touch scanning mode may be arranged to output only touch events and the keypress scanning mode may be arranged to output only keypress events to avoid duplication of outputs.

In practice, a plurality of the rows of the touch sensor may be driven simultaneously, where these rows may be driven using signals with different encodings, different modulations, different phases and/or different amplitudes. These drive signals may each induce a component signal in a column of the touch sensor, where the control unit is able to distinguish between the component signals based on the different encodings of the drive signals to determine the location of a touch or a keypress.

-26 -Typically, the rows are divided into sets, which sets are driven simultaneously. For example, a first set of rows may comprise the first, sixth, eleventh, and sixteenth rows with a second set comprising the second, seventh, twelfth, and seventeenth rows. The rows in these sets are typically selected to be spaced to minimise the number of component signals induced in any of the columns at any given time.

Since the drive signal is typically provided at a high rate, the detection of the induced signals in the columns typically involves processing of induced signals over multiple drive cycles. For example, where the drive rate is 100KHz, each row of the touch sensor is only energised for a very small time; therefore, the processing of an induced signal in a column may occur over a plurality of energisation instances.

Different parts of the keyboard 2000 may use different scanning modes. For example, the touch sensor layer 2060 may comprise a plurality of component touch sensors which operate differently based on different expectations. Users might be expected to perform touch events towards the centre of the keyboard, therefore there may be provided a first component touch sensor in the centre of the keyboard that in a default mode uses long bursts of a touch scanning signal alternated with short bursts of a keypress scanning signal. Conversely, users may be expected to mostly perform keypresses near the edges of the keyboard (e.g. near the spacebar), so there may be provided a second component touch sensor near the edges of the keyboard that in a default mode provides long bursts of a keypress scanning signal alternated with short bursts of a touch scanning signal.

The above description has primarily considered the touch scanning mode processing a signal over a single frame with a substantial time period. It will be appreciated that equally processing may occur over a plurality of frames of a shorter time period. For example, the frames of the touch scanning mode and the keypress scanning mode may be the same, where the touch scanning mode is associated with the combined processing of a greater number of frames (and so a greater scanning period) than the keypress scanning mode.

Touch modes As described above, typically, the keyboard 2000 has a number of input modes, where the keyboard 2000 is capable of switching between the input modes. In particular, the keyboard 2000 typically has at least a pointer input mode and a keypress input mode. The operation of the touch sensor may also differ depending on the input mode that is selected.

In particular, the scanning mode of the keyboard may be dependent on the input mode of the keyboard. As examples, when the keyboard is in a pointer input mode, the default scanning mode may be the touch scanning mode. Equally, when the keyboard is in the keypress input mode the default scanning mode may be the keypress scanning mode. When an unexpected input is detected (e.g. a keypress in the pointer input mode), the keyboard may switch the input mode and/or the scanning mode. It will be appreciated that a variety of input modes are possible, e.g. there may be a mode in which both touch events and keypress events are expected. In such an input mode, the default scanning mode is typically the touch scanning mode as described above.

In various embodiments, one or more of the following inputs are used to change between modes: -a certain keypress relating to a keycap 2050 of the keyboard 2000 (e.g. 'F12'); -27 - - a combination of keypresses (e.g. shift+control+F12); - a gesture detected by the touch sensor layer 2060. In particular, to switch to/from the pointer input mode, a gesture may be used such as a finger tap, a one-finger movement, a two-finger movement, a relative movement of two or more fingers (e.g. a pinch, vertical or horizontal swipes with three or four fingers or a grab in/out with four or five fingers).

In order to avoid undesired switching between input modes and/or scanning modes, one or more of the following factors may also, or alternatively, be considered: the position of a user's hands on the keyboard 2000. For example, if the user's hands are positioned in a typical typing position (e.g. with index fingers resting on the T and 1 keys) the keyboard may be locked in the keypress input mode and/or the keypress scanning mode; - the number, or location, of a user's hands and/or fingers on the keyboard 2000.

- a resting time of a user's hands, e.g. if they have been stationary on the keyboard for a certain amount of time; - a previous or current action, e.g. if the user has been typing for a continuous period (or is currently typing). Typically, there is a delay between the last detected keypress and the consideration of a mode-switching input, e.g. it may not be possible to switch to the pointer input mode until at least 100ms after depressing a keycap in the keypress input mode.

- The context of a connected computer device. In particular, the applications open on the device and the current focus may be determined. For example, where an image editing application is open a grabbing gesture may enter an image editing mode; where a web browser is open, the same grabbing gesture may enter a scrolling mode.

The mode changing inputs and the factors to avoid undesired switching may be controlled by a user.

Alternatives and modifications It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

In some embodiments, the keyboard 2000 comprises both a keypress sensor layer and a touch sensor layer. For example, the touch sensor layer may cover only a subset of the keyboard, where the touch sensor layer is arranged to detect keypresses in this subset and the keypress sensor layer is arranged to detect keypresses outside of this subset.

Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.

Claims

-28 -Claims 1 A keyboard comprising: a plurality of keys; and a touch sensor for detecting a touch of a user on the keys; wherein the keyboard is arranged to detect a keypress relating to the keys using the touch sensor; and wherein the keyboard is arranged to process signals from the touch sensor based on: a first scanning mode associated with a first scanning period; and a second scanning mode associated with a second scanning period; wherein the first scanning period is greater than the second scanning period.
2. The keyboard of any preceding claim, wherein each key is associated with a conductive coating, such that when said key is pressed the corresponding coating moves relative to the touch sensor.
3 The keyboard of claim 2, wherein each coating is arranged on a transmittal mechanism of the corresponding key, preferably wherein each coating is arranged on: an exterior surface, an interior surface, and/or a tip of the transmittal mechanism, preferably wherein the transmittal mechanism comprises a dome.
4. The keyboard of claim 2 or 3, wherein the coating comprises a metal coating, preferably wherein the coating comprises a metal oxide semiconductor.
5. The keyboard of any preceding claim, wherein the touch sensor comprises a capacitive sensor.
6. The keyboard of any preceding claim, wherein the touch sensor comprises a mutual capacitance sensor.
7. The keyboard of any preceding claim, wherein the touch sensor comprises a self capacitance sensor.
8. The keyboard of any preceding claim, wherein the touch sensor is arranged to operate in: a mutual capacitance mode; and a self capacitance mode.
9. The keyboard of any preceding claim, wherein the first scanning mode comprises a mutual capacitance mode and the second scanning mode comprises a self capacitance mode.
10. The keyboard of any of claims 1 to 8, wherein each of the first scanning mode and the second scanning mode comprises a mutual capacitance mode.
11. The keyboard of any preceding claim, wherein the touch sensor is arranged to operate based on a third scanning mode associated with a third scanning period, preferably wherein the -29 -second scanning period is greater than the third scanning period, more preferably wherein the third scanning period is no more than 2ms, yet more preferably wherein the third scanning rate is in the range of lms -2ms.
12. The keyboard of claim 11, wherein the third scanning mode comprises a self capacitance mode, preferably wherein the second scanning mode comprises a mutual capacitance mode.
13. The keyboard of any preceding claim, wherein the touch sensor is arranged to switch: from the first scanning mode to the second scanning mode, and/or from the first scanning mode to a/the third scanning mode, and/or from a/the third scanning mode to the second scanning mode, based on the detecting of a keypress, preferably wherein the first scanning mode is the default mode
14 The keyboard of any preceding claim, wherein the touch sensor is arranged to switch: from the second scanning mode to the first scanning mode, and/or from a/the third scanning mode to the first scanning mode, in dependence on the touch sensor not detecting a keypress for a threshold time, preferably wherein the threshold time is no more than 10ms.
15. The keyboard of claim 13 or 14, wherein detecting a keypress comprises detecting a signal, and/or an integrated signal, with a magnitude that exceeds a threshold magnitude.
16. The keyboard of any preceding claim, wherein the touch sensor is arranged to operate in the first mode and the second mode alternately.
17. The keyboard of any of claims 1 to 15, wherein the touch sensor is arranged to operate in the first mode and the second mode simultaneously.
18. The keyboard of any preceding claim, wherein the touch sensor is arranged to operate using a combined frame, the combined frame comprising a first frame associated with the first scanning mode and one or more, preferably a plurality of, second frames associated with the second drive scanning mode.
19. The keyboard of any preceding claim, wherein the keyboard is arranged to output only touch events in the first scanning mode and/or to output only keypress events in the second scanning mode.
20. The keyboard of any preceding claim, wherein the keyboard is arranged to detect an event by integrating a signal of the touch sensor over the scanning period.
21. The keyboard of any preceding claim, comprising a control unit, wherein the control unit is arranged to: control the keyboard and/or the touch sensor; alter a scanning mode of the keyboard; and/or process signals from the touch sensor in order to detect touch events and/or keypresses.-30 -
22. The keyboard of claim 20, wherein the control unit is arranged to distinguish between a touch of a user and a keypress, preferably based on one or more of: a magnitude of a change measured by the touch sensor; a duration of a change measured by the touch sensor; a rate of a change measured by the touch sensor; a direction of a movement measured by the touch sensor; and a mode of the keyboard.
23. The keyboard of any preceding claim, being arranged to operate in a plurality of input modes, wherein a/the scanning mode used by the touch sensor is dependent on a selected input mode, preferably wherein the input modes include a pointer input mode and a keypress input mode.
24 The keyboard of any preceding claim, wherein: the first scanning period is at least 5ms, is greater than 5ms, and/or is in the range of 5ms -10ms; and/or the second scanning period is no more than 5ms, is less than 5ms, and/or is in the range of 2ms -5ms, preferably wherein the second scanning mode is a mutual capacitance scanning mode; or the second scanning period is no more than 2ms, yet more preferably wherein the third scanning rate is in the range of 1ms -2ms, preferably wherein the second scanning mode is a self capacitance scanning mode.
25 The keyboard of any preceding claim, wherein the touch sensor comprises a plurality of rows and columns of electrodes, preferably wherein the touch sensor is arranged so that the keys and/or the coatings are located above intersections of the rows and columns of electrodes.
26 A keyboard comprising: a plurality of keys; and a touch sensor for detecting a touch of a user on the keys; wherein the keyboard is arranged to detect a keypress relating to the keys using the touch sensor; and wherein the keyboard is arranged to process signals from the touch sensor based on: a first scanning mode associated with a first scanning rate; and a second scanning mode with a second scanning rate; wherein the second scanning rate is greater than the first scanning rate.