Touch Sensitive Apparatus

Field of the Invention

The invention relates to touch sensitive apparatus.

Background

It is well known for mobile phones and other such devices to include touch sensitive panels.

Summary

This specification discloses an apparatus comprising a touch sensitive input panel operable to detect a location of a touch input and a pressure pad arranged to detect a force due to the touch input.

The touch sensitive input panel may be transparent and the apparatus may further comprise a display panel, a display surface of the display panel being visible through the touch sensitive input panel.

The touch sensitive input panel may be a capacitive touch sensitive panel. The display panel may be an LCD panel.

The pressure pad may comprise a tube, the tube being connected to a pressure sensor for detecting pressure of gas within the tube.

A first end of the tube may be sealed and a second end of the tube may be in sealed connection with the pressure sensor.

Alternatively, the first end of the tube may be in sealed connection with a portion of the tube near to the second end, wherein said portion comprises an aperture and the first end is sealed around said aperture.

The tube may be arranged around a perimeter portion of the display panel.

The tube may comprise a soft elastomer.

The pressure sensor may be mounted on a printed circuit board.

The pressure sensor may be in communication with a processor and the processor may be arranged to determine the force due to the touch input based at least partly on the detected pressure.

The processor may be arranged to register the touch input if the detected force exceeds a predetermined threshold.

The touch sensitive panel may be in communication with the processor and the processor may be arranged to determine a location of the touch input.

The processor may be arranged to register the touch input if the detected force exceeds a predetermined threshold, and the location of the touch input corresponds to an option displayed on the display surface.

The pressure pad may be interposed between the touch sensitive input panel and the display panel.

The tube may be arranged around a perimeter portion of the display surface and the pressure pad may further comprise first and second extension members, the first extension member extending from the tube in a direction perpendicular to the display surface and the second extension member extending from an end of the first extension member in a direction parallel to the display panel surface, the tube and the first and second extension members forming a recess parallel to the display surface, and an edge of the touch sensitive panel may be provided within the recess.

Alternatively, the display panel may be interposed between the touch sensitive panel and the pressure pad. A gasket may be interposed between the display panel and the touch sensitive panel.

The pressure pad may comprise a tube, and the apparatus may further comprise a tactile feedback mechanism configured to provide tactile feedback to a user by reducing the gas pressure within the tube in response to a force of the touch input crossing from below to above a feedback threshold.

The tactile feedback mechanism may be configured to increase the gas pressure within the tube in response to the force of the touch input crossing from above to below the feedback threshold.

The tactile feedback mechanism may comprise a projection member, and a switch, wherein the projection member is configured such that an increased gas pressure within the tube due to an applied touch input causes an increased projection and such that the increased projection causes the gas pressure to be reduced, and wherein the switch is configured, in a first state, to prevent substantially the increased projection of the projection member, and, in a second state, to allow the increased projection of the projection member, and wherein the switch is configured to switch from the first state to the second state in response to a force exerted thereon by the projection member crossing from below to above a switching threshold, wherein the switching threshold corresponds to the feedback threshold.

The switch may be configured to switch from the second state to the first state, in response to a force exerted thereon by the projection member crossing from above to below a switching threshold.

The projection member may comprise a diaphragm.

The switch may comprise a dome switch.

The touch sensitive input panel may comprise a spacing layer interposed between two sub-layers, and the pressure pad may comprise the spacing layer and a pressure sensor configured to detect pressure of gas within the spacing layer.

The touch sensitive input panel may comprise a resistive touch sensitive input panel, and the two sub-layers may be conducting sub-layers.

This specification also discloses a method comprising detecting a force of a received touch input, determining if the force is greater than a predetermined threshold, and, if the force is greater than a predetermined threshold, registering the input.

Detecting the force may comprise detecting a pressure change of gas within a pressure pad, the pressure change being due to the received touch input. The pressure change may be due to compression of the pressure pad due to the received touch input.

The method may further comprise determining a location of the touch input, determining if the location of the touch input corresponds to a selectable option, and, only if the location of the touch input corresponds to a selectable option and the force is greater than a predetermined threshold, registering the input.

Registering the input may comprise altering a display based at least partly on the selectable option.

Determining if the force is greater than a predetermined threshold may comprise determining if the force is greater than one or more predetermined thresholds, whereby registering the input may comprise altering a display also based at least partly on which of the one or more predetermined thresholds the force exceeds.

The specification also discloses a method comprising providing a display panel, a touch sensitive panel, and a tube, a first end of the tube being sealed and a second end being open, fixing the tube to display panel, fixing the touch sensitive panel to the tube or the display panel, and attaching, in a sealed connection, a pressure sensor to the second end of the tube.

Fixing the tube to the display panel may comprise fixing a first outer surface of the tube to a display surface of the display panel, and fixing the touch sensitive panel may comprise fixing the touch sensitive panel to a second outer surface of the tube, the second outer surface being opposite the first outer surface.

Alternatively, fixing the tube to the display panel may comprise fixing the tube to a surface opposite a display surface of the display panel, and fixing the touch sensitive panel may comprise fixing the touch sensitive panel to the display surface of the display panel.

This specification further discloses an apparatus comprising a touch sensitive input panel operable to detect a location of a touch input and a tactile feedback

unit in communication with the touch sensitive input panel, the tactile feedback unit being configured to provide tactile feedback to a user applying the touch input, wherein the tactile feedback unit comprises a tube and a tactile feedback mechanism configured to reduce the gas pressure within the tube in response to the gas pressure within the tube crossing from below to above a feedback threshold.

The tactile feedback mechanism may comprise a projection member and a switch, wherein the projection member is configured such that an increased gas pressure within the tube due to an applied touch input causes an increased projection and such that the increased projection causes the gas pressure to be reduced, the switch is configured, in a first state, to prevent substantially the increased projection of the projection member, and, in a second state, to allow the increased projection of the projection member, and wherein the switch is configured to switch from the first state to the second state in response to a force exerted thereon by the projection member crossing from below to above a switching threshold, wherein the switching threshold corresponds to the feedback threshold.

The specification further discloses an apparatus comprising a touch sensitive input panel operable to detect a location of a touch input and to detect a force due to the touch input, the touch sensitive input panel comprising a gas-filled spacing layer interposed between two solid sub-layers, and a pressure sensor configured to detect a pressure of the gas within the spacing layer.

The touch sensitive input panel may be a resistive touch sensitive input panel wherein surfaces of sub-layers adjacent to the spacing layer have a coating of electrically conducting material provided thereon.

Brief Description of the Drawings

In order that the invention may be more fully understood, embodiments thereof will be described by way of illustrative example with reference to the accompanying drawings in which like reference numerals refer to like elements and wherein:

Figure 1 shows a mobile phone terminal in which the invention can be embodied;

Figure 2A shows an expanded view of a first embodiment of the invention;

Figure 2B shows an unexpanded view of the apparatus of Figure 2A;

Figure 2C show the apparatus of Figures 2A and 2B undergoing a touch input;

Figure 3 shows a plan view of an end portion of the apparatus of Figures 2A to 2C;

Figure 4 shows an alternative embodiment of the invention;

Figure 5 shows a second alternative embodiment of the invention;

Figure 6A shows a third alternative embodiment of the invention;

Figure 6B shows a cross-sectional view of the apparatus of Figure 6A; Figure 7 shows a schematic of an example of circuitry utilised in the operation of any embodiments of the invention;

Figure 8 shows a flow diagram depicting an example of an operation of any embodiments of the invention;

Figure 9 shows a flow diagram depicting an example of a method of manufacture of any embodiments of the invention;

Figure 10 is a three-dimensional schematic cut-away view of a fourth alternative embodiment of the invention;

Figures 1 1 A and 11 B are a three-dimensional schematic view and a plan-view of an end portion of a touch sensitive device operable to provide tactile feedback to a user;

Figure 12A and 12B are cross-sectional schematic views through an example of various embodiments of a tactile feedback module.

Detailed Description of the Embodiments Figure 1 shows an example of a mobile phone terminal 10 having a cover 100 and a touch sensitive display 102, a visible region of the touch sensitive display 102 being defined by a window 104 formed in the cover 100. The phone 10 also has a speaker 106 and a microphone 108. Displayed on the touch sensitive display 102 are an input display 1 10, ten numeral keys (0 to 9) 112, 1 14, 116, 1 18, 120, 122, 124, 126, 128, 130, a star key 132, a hash key 134, a call key 136, and a cancel key 138. The mobile phone terminal also has a physical key 140. It should be understood that the mobile phone alternatively may not include a physical key or may have more than one physical key. The physical key 140 could have any number of different functions, one of which might be, for example, closing down an application currently being viewed.

A user can select a number or option by providing a touch input to a region of the touch sensitive display on which the number or option is displayed. The touch input can be provided by, for example, the user's finger or a stylus.

While the embodiment shown in Figure 1 is a mobile phone terminal 10, it should be understood that the invention also applies to other devices such as communicators, PDA devices, multimedia computers, and portable multimedia players.

Figures 2A and 2B are, respectively, expanded and unexpanded three- dimensional schematics of the touch sensitive display 102 of the mobile phone terminal 10. The touch sensitive display 102 comprises a display panel 200, having a rectangular shaped display surface 202. It will be appreciated, however, that other shapes, for example a square, may also be suitable. The display panel 200 may be an LCD display screen, the operation and construction of which are well known in the art. It should be understood, however, that other suitable types of display panel may be used instead. Displayed by the display panel are the input display 1 10, the ten numeral keys 112, 114, 1 16, 118, 120, 122, 124, 126, 128, 130, the star key 132, the hash key 134, the call key 136, and the cancel key 138.

The touch sensitive display further comprises a pressure pad 204, the pressure pad being contacted to the display surface 202 of the display panel 200. The pressure pad 204 comprises a tube 205, having a square cross section. The dimensions of the cross section of the tube may be approximately 1 mm x 1 mm. It should be understood that various other cross-sectional shapes may also be suitable. Such suitable shapes include, but are not limited to, rectangular, circular, double concave (i.e. generally rectangular but with two opposing concave sides), or double convex (i.e. generally rectangular but with two opposing convex sides). It should also be understood that alternative dimensions may also be suitable. The tube 205 is arranged such that a first outer surface 206 of the tube 205 is contacted to a perimeter portion 207 of the display surface 202. The perimeter portion 207 of the display surface 202 is a portion of the display surface in which images are not displayed. Due to the display surface 202 being rectangular and the tube 205 being in contact with a perimeter portion 207 of the display surface 202, the tube 205 forms a generally rectangular shape. The second outer surface 208 of the tube 205 is generally

aligned with the perimeter of the display surface 202. A first end 209 of the tube 205 is sealed. A second end 210 is in sealed connection with a pressure sensor 211 . An end portion 212 of the tube 205, immediately preceding the second end 210 of the tube 205, extends beyond an edge 214 of the display surface 202. Alternatively, the second end 210 of the tube 205 may be aligned with the edge 214 of the display surface 202. The first end 209 of the tube 205 adjoins a portion of a third outer surface 216 of the tube 205, the portion being in adjacent to the edge 214 of the display surface 202.

Alternatively, the first end 209 of the tube 205 may be in sealed connection with the portion of the third outer surface 216 of the tube 205 adjacent to the edge 214 of the display surface 202. The pressure sensor 21 1 is in sealed connection with the second end 210 of the tube 205. The portion of the third outer surface 216 of the tube 205 adjacent to the edge 214 of the display surface 202 may comprise an aperture around which the first end 209 of the tube 205 is sealed. The tube thus formed is a continuous tube with an extension thereof attached to the pressure sensor 211 .

The pressure sensor 211 is arranged to detect the pressure of air within the tube 205. The tube 205 may be constructed of a soft elastomer, for example silicone. The tube may have a wall thickness of approximately 0.3mm. Again, it should be understood that different wall thicknesses and materials may also be suitable.

The touch sensitive display 102 further comprises a touch sensitive panel 220. The touch sensitive panel 220 has a first surface 222, being a touch sensitive surface arranged to receive a touch input, and, opposite the first surface 222, a second surface 224. The first and second surfaces 222, 224 of the touch sensitive panel 220 have generally the same dimensions as the display surface 202 of the display panel 200. The touch sensitive panel 220 is generally aligned with the pressure pad 204 and the display panel 200. The second surface 224 of the touch sensitive panel 220 is contacted to a fourth outer surface 225 of the tube 205, such that the pressure pad 204 is interposed between the display panel 200 and the touch sensitive panel 220. This can be seen clearly in Figure 2B. The touch sensitive panel 220 is constructed of transparent material. The touch sensitive panel 220 may be a capacitive touch

sensitive panel, the operation and construction of which is well known in the art. Other types of touch sensitive panel may also be appropriate.

Due to the transparency of the touch sensitive panel 220, an image displayed by the display panel 200 is visible through the touch sensitive panel 220. Therefore, when a user desires to select a key, a touch input is provided to a region of the touch sensitive surface 222 corresponding to a region of the display surface 202 on which the desired key is displayed. This can be seen in Figure 2C, in which the user wishes to select the "6" key 122. Due to the touch input, a force (denoted by the arrow F) is exerted on the touch sensitive panel 220 in a direction generally perpendicular to touch sensitive surface 222. This force is transferred through the touch sensitive panel 220 onto pressure pad 204, which causes the tube 205 to compress. This compression of the tube 205 causes an interior volume of tube 205 to decrease, which in turn results in a change (an increase) in the pressure of the air within the tube 205. This pressure change is detected by the pressure sensor 211 .

Figure 3 is a plan view of an end portion of the touch sensitive display 102. The touch sensitive panel 220, the end portion 212 of the tube 205 and the pressure sensor 211 underlie the cover 100. The pressure sensor 211 is a surface mounted device (SMD) and is mounted on a printed circuit board (PCB) 226. SMD pressure sensors are currently available in sizes of approximately 6mm ^χ 6mm ^χ 3mm. Other internal components can also be mounted on the PCB 226, for example a main processor (not shown) and a memory (not shown). Visible through the touch sensitive panel 220 are various keys 118, 120, 122, 124, 126, 128, 130, 132, 134 being displayed by underlying display panel (not visible).

Figure 4 shows a first alternative embodiment of the touch sensitive display 102. In this embodiment, the display surface 202 of the display panel 200 is aligned with, and contacted to, the second surface 224 of the touch sensitive panel 202. The fourth outer surface 225 of the tube 205 is contacted to perimeter portion (not visible) of a second surface 228, opposite to the display surface 202, of the display panel 200. As such, the display panel 200 is interposed between the pressure pad 204 and the touch sensitive panel 220.

Figure 5 shows a second alternative embodiment of the touch sensitive display 102. This embodiment is of the same construction as the embodiment of Figure 4, but includes a display gasket 230 interposed between the display panel 200 and the touch sensitive panel 220.

Figure 6A and 6B, respectively, show three-dimensional and cross-sectional views of a third alternative embodiment of the touch sensitive display 102. Figure 6B is a view of a cross-section of the touch sensitive display labelled A in Figure 6A. This embodiment comprises the display panel 200, the touch sensitive panel 220 and a pressure pad 604. In this embodiment, the pressure pad 604 comprises a tube 605 having a generally square cross section (as can be seen in Figure 6B).

A first outer surface 606 of the tube 605 is in contact with a perimeter portion 207 of the display surface 202 of the display panel 200. Subsequently, the tube 605 forms a rectangular shape, with a second outer surface 609 of the tube 605 being aligned with the perimeter of the display surface 202. The tube 605 further comprises a first extension member 632 extending from and parallel to a second outer surface 608 of the tube 605. The tube also further comprises a second extension member 634 extending at right angles from the first extension member 632 and aligned with the fourth outer surface 621 of the tube 605. The fourth outer surface 621 of the tube 605, the first extension member 632 and the second extension member 634 form a recess, the recess being parallel to the display surface 202.

A first end (not visible) of the tube 605 is sealed and a second end 610 is in sealed connection with a pressure sensor 611 . The pressure sensor 611 may be the same as that described with reference to the first and other alternative embodiments. An end portion 612 immediately preceding the second end 610 of the tube 605 extends beyond an edge 214 of the display surface 202.

Alternatively the second end 610 of the tube 605 may be aligned with the edge 214 of the display surface 202. The first end of the tube 605 adjoins a portion of a third outer surface 609 of the tube 605, the portion being adjacent to the edge 214 of the display surface 202.

A perimeter portion 236 of the touch sensitive panel 220 sits within the recess formed by the fourth outer surface 621 of the tube 605, the first extension

member 632 and the second extension member 634, such that the first extension member 632 surrounds all perimeter surfaces 636 of the touch sensitive panel 220.

As with the other embodiments, the tube may comprise a soft elastomer, such as silicone, and may have a wall thickness of 0.3mm and the square cross section may have dimensions of approximately 1 mm x 1 mm. As mentioned previously, it should be understood that different materials, cross-sectional shapes, cross-sectional dimensions and wall thicknesses may also be suitable.

Figure 7 shows an exemplary configuration of circuitry associated with the touch sensitive display 102. An output of the touch sensitive panel 220 is connected to a first input of a main processor 700. An output of the pressure sensor 211 is connected to a second input of the main processor 700. In two- way connection with the main processor 700 is a memory 702. Connected to an output of the main processor 700 is an input of the display panel 200. Software programs for execution by the main processor are stored on the memory 702. It should be understood that, although the pressure pad 205 is shown in Figure 7 as interposed between the display panel 200 and the touch sensitive display 220, the associated circuitry may be the same if, for example, the touch sensitive display is arranged as seen in Figures 4 and 5.

The operation of the touch sensitive display 102 and its associated circuitry will now be described with reference to Figure 8. Depending on a user selected mode, for example a dial mode, the main processor 700 outputs signals to the display panel 200 instructing the display panel to display a particular image. As described above with reference to Figure 1 , the image may comprise a representation of a key pad, consisting of a plurality of keys 112, 1 14, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, and also an input display 110. At this point, the touch sensitive display 102 awaits a touch input S1.

When a touch input is received S2 at the touch sensitive panel 220, a signal is generated by the touch sensitive panel 220 and is transmitted to the processor 700. The processor 700 then executes a first program stored on the memory 702 to determine S3, based at least partly on the signal received from the touch sensitive panel 220, the location of the touch input on the touch sensitive panel 220.

The force provided by the touch input results in the compression of the tube 205. As discussed, the compression of the tube 205 results in an increase in the pressure of the air within the tube. This increase is detected by the pressure sensor 211 and is communicated to the processor 700 via an electric signal. Having received this electric signal, the processor 700 executes a second program stored on the memory 702 to determine S4, based at least partly on the pressure increase of the air within the tube 205, the force exerted on the touch sensitive panel 220 due to the touch input.

In the next step S5, the processor 700 executes a third program stored on the memory 702 to determine if the location of the touch input on the touch sensitive panel 220 corresponds to a region of the display panel 200 on which a key is being displayed. The processor 700 also executes a fourth program stored on the memory 702 to determine if the force determined in the previous step S4 is greater than a predetermined threshold. The predetermined threshold may be, but certainly not limited to, a value between 1 N and 5N and may be defined by a manufacturer or may be user-defined. If either one of the conditions (i.e. the location of the touch input corresponding to a region of the display panel 200 on which a key is being displayed, and the calculated force exceeding a predetermined threshold) is not met, then no input is registered by the processor 700 and the processor 700 returns to awaiting a touch input. If, however, both conditions are satisfied, the processor 700 instructs the display panel 200 to display on the input display 110 a numeral or symbol corresponding to the selected key. For example, if a user provides a touch input, having sufficient force, to a location on the touch sensitive panel corresponding to the region 122 of the display panel 200 on which "6" is displayed, the processor 700 will instruct the display panel 200 to display a "6" in the input display region 1 10 of the display panel. Following a registered input, the processor 700 returns to awaiting a touch input.

There may, alternatively, be more than one predetermined threshold, whereby a selected key has a different function depending on the threshold exceeded. For example, if a touch input, having a force greater that a first threshold (for example 2N) but less than a second threshold (for example 5N), is detected in a location on the touch sensitive panel corresponding to the region 122 of the display panel 200 on which "6" is displayed, the processor 700 may instruct the display panel 200 to display a "6" in the input display region 110 of the display

panel. However, if a touch input, having a force greater than the second threshold, is detected in the same location, the processor 700 may instruct the display panel to display, for example, a predefined "quick dial" telephone number corresponding to the selected region of the display screen (for example stored in a sixth "quick dial" slot).

The method of operation has been described with reference to dialling a telephone number on a mobile telephone. In this situation, it is necessary for the apparatus to determine if the location of the touch input. It should be understood, however, that there may be some situations in which the location of the touch input is not important. This may occur, for example, if a user is watching a video and they wish to bring up a menu. In this situation the user may provide a touch input to anywhere on the display screen. Therefore, in this case, the method of operation may not include the determination of the location of the touch input, or the determination of whether location corresponds to a selectable option.

A method of assembly of the embodiments of the touch sensitive display 102 will now be described with reference to Figure 9.

At the first step M1 , the touch sensitive panel 220, the display panel 200 and the tube 205; 605 are provided. The first end 209 of the tube 205 is sealed and the second end 210; 610 is open. At the second step M2, the tube 205; 605 is fixed to the display panel 200. Depending on the embodiment under manufacture, the first outer surface 206 of the tube 205, 605 may be fixed to the perimeter portion 207 of the display surface 202 (as in the embodiments of Figures 2 and 6) or alternatively the third outer surface 221 ; 621 of the tube 205; 605 may be fixed to a perimeter portion of the second surface 228 of the display panel 200 (as in the embodiments of Figures 4 and 5). In the next step M3, the touch sensitive panel 220 is fixed. Again, depending on the embodiment under manufacture, the position in which the touch sensitive panel 220 is fixed may vary. The second surface 224 of the touch sensitive panel 220 may be fixed to the third surface 221 ; 621 of the tube 205; 605 (as in the embodiments of Figures 2 and 6). Alternatively, the second surface 224 of the touch sensitive panel 220 may be fixed to the display surface 202 of the display panel 200, either directly (as in the embodiment of Figure 4) or via a display gasket 230 (as in the embodiment of Figure 5). Finally, when the display panel

200, the tube 205; 605 and the touch sensitive panel 220 are correctly positioned, the pressure sensor 211 ; 611 is attached M4 in a sealed connection with the second end of the tube 210; 610.

After the touch sensitive display 102 has been assembled, the pressure sensor 211 can be connected to the processor 700. At this point, the processor 700 can be instructed to execute a tare program, stored on the memory 702. The tare program causes the processor to register a reference pressure value (either by storing the reference pressure value on the memory 702 or in another way). The reference pressure value is a pressure value detected by the pressure sensor 211 when no touch input is provided to the touch sensitive display 102. This reference pressure value will then be utilised by the processor 700 during execution of the second program to determine the force due to a touch input.

However, due to changes in device temperature, ambient temperature and air pressure, the pressure detected by the pressure sensor 211 , when no touch input is being provided, may vary. Therefore, in order to negate any potential problems caused by this, the processor 700 can be programmed to execute the tare program, thereby resetting the reference pressure value, on a regular basis. The regularity of the execution of the tare program may be defined by the manufacturer or may be defined by the user.

The touch sensitive display imitates a normal keypad in that, in order for an input to be registered, a sufficient force must be applied. This means that, in order for a user to select an option displayed on the screen, a deliberate pressing action is required and, therefore, the chance of erroneous inputs due to erroneous touch inputs (that may happen, for example, when the mobile phone terminal is in the user's pocket or bag) is reduced.

The provision of the pressure pad in the touch sensitive display increases the tolerance of the display (and the device in which it is included) to components having dimensional variances. This is because, due to its soft elastomeric nature, the tube can compress, its shape adapting to compensate for the dimensional variances. Furthermore, as the pressure sensor is not attached, and therefore the tube is not sealed, until after the other components have been assembled, these dimensional variances do not affect the pressure of the air

within the tube. Therefore, prior to a touch input, the pressure sensor will detect the same pressure (approximately 1 atm.) regardless of any dimensional variances.

Figure 10 is a three-dimensional schematic cut-away view of an example of a touch sensitive display 1000 according to alternative embodiments.

The touch sensitive display 1000 of Figure 10 comprises a resistive touch sensitive panel 1002 and a display panel 1003. The resistive touch sensitive panel 1002 comprises a glass substrate layer 1004 coated with indium tin oxide (ITO) 1006, which is a transparent conducting material. A flexible polyester (PET) membrane layer 1007 also coated with ITO 1008 is suspended above the glass substrate layer 1004 on a gasket 1010 provided around the perimeter of the glass substrate layer 1004. Transparent spacer dots 1012 separate the two conducting surfaces, i.e. the ITO coated surfaces 1006, 1008 of the glass substrate layer 1004 and the PET membrane layer 1007. The gasket 1010 and spacer dots 1012 act to form an air gap 1014 between the conducting surfaces. Provided atop the PET membrane layer 1007 is a hardcoat layer 1016. The hardcoat layer 1016 makes the surface of the PET membrane layer 1007 more resistant to wear.

An aperture (not shown) is formed in the gasket 1010 from an exterior surface 1011 of the gasket 1010 to an interior surface 1013 of the gasket 1010. In airtight connection with the region of exterior surface 101 1 of the gasket 1010 surrounding the aperture is a first end 1018 of a tube 1020. In airtight connection with a second end 1022 of the tube 1020 is a pressure sensor 1024. The gasket 1010 is hermetically sealed to both the ITO coated 1006 glass substrate layer 1004 and the ITO coated 1008 PET layer 1007. As such, the gas within the air gap 1014 and the tube 1020 is unable to escape. The pressure sensor 1024 is operable to detect the pressure of the gas within the air gap 1014 and the tube 1020.

According to alternative embodiments, the pressure sensor 1024 may be in direct communication with the aperture. Embodiments such as these do not include the tube 1020 between the aperture and the pressure sensor 1024.

The display panel 1003 is located beneath the touch sensitive panel 1002. Images displayed on the display panel 1003 are visible to the user through the touch sensitive panel 1002. The display panel 1003 may be an LCD display screen, the operation and construction of which are well known in the art. It should be understood, however, that other suitable types of display panel may be used instead.

It will be understood that the touch sensitive panel may comprise additional layers (not shown), for example polarising layers.

The resistive touch sensitive panel 1002 is operable to detect touch inputs in the following way. When a touch input is incident on the outer surface of the hardcoat layer 1016, the associated force of the touch input causes the PET membrane layer 1007 to bend towards the glass substrate layer 1004. This causes a change in separation, and thus a change in the resistance, between the two ITO layers 1006, 1008. Electronic circuitry (not shown) measures the resistance along the edges in two dimensions and calculates the location of touch input.

The bending of the PET membrane layer 1007 towards the glass substrate also causes a reduction of the volume of the gas within the air gap 1014. As such, the touch input also results in an increase in the pressure of gas within the air gap 1014. This pressure change is detected by the pressure sensor 1024. Based on signals subsequently received from the pressure sensor 1024, a processor (not shown) is operable to determine the force of the applied touch input. As such, the pressure pad for detecting force due to a touch input is physically integrated with the touch sensitive panel 1002. According to this embodiment, the pressure pad is constituted by the air gap 1014 of the touch resistive panel 1002, and the pressure sensor 1024. The pressure pad optionally may comprise the tube 1020 between the air gap 1014 and the pressure sensor 1024. Consequently, according to these embodiments, an additional pressure pad is not required.

It will appreciated that the methods described with reference to Figure 8 may also be carried out using embodiments such as that described with reference to Figure 10.

It will be appreciated also that embodiments as described with reference to Figure 10 may have associated circuitry as described with reference to Figure 7.

It will be well understood that any type of touch sensitive panel that can be manufactured to comprise an air gap, such that an applied touch input results in a increase in gas pressure within the air gap, may be modified according to the embodiment of Figure 10 so as to allow measurement of the force of a touch input based on detected gas pressure within the air gap.

According to various alternative embodiments, a touch sensitive device 1102 is operable to provide tactile feedback to a user applying a touch input to the first, or upper, surface 1 104 of the touch sensitive panel 1 106.

Figures 1 1 A and 11 B are a three-dimensional schematic view and a plan-view of an end portion respectively of an example of a touch sensitive device 1 102 operable to provide tactile feedback to a user. The touch sensitive device 1102 comprises a touch sensitive panel 1 106, a pressure pad 1108, and display panel 11 10. The touch sensitive panel 1106 and the display panel 11 10 may be the same as those described with reference to the above embodiments.

The pressure pad 1108 is substantially the same as the exemplary embodiments described with reference to Figures 2 to 5. Alternatively, the pressure pad 1 108 may be substantially the same as the exemplary embodiments described with reference to Figures 6A and 6B.

The pressure pad 1 108 of Figures 1 1A and 11 B further comprises a branch tube 11 12. A first end 1 114 of the branch tube 1 112 is in sealed communication around an aperture (not shown) formed in the end portion 11 18 of the pressure pad 1 108. As such, air is able to flow freely from the end portion 11 18 to the branch tube 11 12.

In sealed connection with a second end 1120 of the branch section 11 12 is a tactile feedback module 1122. The tactile feedback module 1122 is operable to cause tactile feedback to be provided to a user applying a touch input to the upper surface 1 104 of the touch sensitive panel 1106.

When a touch input is applied to the upper surface 1104 of the touch sensitive panel 1106, the force of the touch input is transferred by the touch sensitive panel 1106 to the pressure pad 1108. The application of the force on the pressure pad 1108 causes the pressure pad 1 108 to deform and the gas pressure within the pressure pad 1108 to increase. The tactile feedback module 1122 is operable, in response to the pressure of the gas within the pressure pad 1108 crossing from below to above a predetermined feedback threshold, to reduce suddenly the gas pressure within the pressure pad 1108 by a predetermined amount. The predetermined feedback threshold may correspond to a force in the range of, for example, 2N to 5N, being applied to the upper surface 1 104 of the touch sensitive panel 1 106.

A reduced gas pressure within the pressure pad 1 108 results in a reduced resistance to deformation due to the incident force of the touch input. As such, following the sudden reduction of the gas pressure, the pressure pad 1108 suddenly becomes more easily deformed. As such, following the sudden reduction in gas pressure, the force of the touch input causes the pressure pad 1 108 to compress suddenly in the direction of the force of the applied touch input. The user experiences this deformation as a sudden movement of the touch sensitive panel 1106 in a direction substantially away from their finger or stylus etc.

The tactile feedback module 1 122 is operable also, in response to the pressure of the gas within the pressure pad 1 108 crossing from above to below the predetermined feedback threshold, to increase suddenly the gas pressure within the pressure pad 1 108 by the predetermined amount.

An increased gas pressure within the pressure pad 1108 results in an increased resistance to deformation. As such, following the sudden increase of the gas pressure, the pressure pad 1 108 suddenly becomes less compressed. The user experiences this reformation as a sudden movement of the touch sensitive panel 1108 in a direction substantially towards their finger or stylus etc.

The provision of a sudden movement of the touch sensitive panel 1106 away from the user's finger in response to the force of a touch input passing above a feedback threshold simulates the action of the button or a key of a keypad or keyboard being pressed by a user. The provision of a sudden movement

towards the user's finger when the force of the touch input passes back under the feedback threshold, simulates the action of the button or a key of a keypad or keyboard being released by a user. They also provide the user with a clear tactile indication that they have successfully entered an input. In this way, the experience of a user operating the touch sensitive display 1102 is improved.

Figure 12A and 12B are cross-sectional schematic views through an example of various embodiments of the tactile feedback module 1 122.

The tactile feedback module 1 122 comprises an extension portion 1202 and a switch portion 1204. The extension portion 1202 is in sealed communication with the second end 1 120 of the branch tube 11 12 of the pressure pad 1 108.

The extension portion 1202 comprises a moulded body portion 1206. The moulded body portion 1206 comprises a first opening 1208 in a first end 1210 of the mould body portion 1206. The first opening 1208 is shaped so as to receive, in airtight communication, the second end 1 120 of the branch tube 1 112. A second opening 1212 is located at a second end 1214 of the moulded body portion 1206. The second opening 1212 is circular. It will be appreciated, however, that the second opening 1212 may have a different shape. The moulded body portion 1206 may be physically integrated into the housing of the device into which the touch sensitive display 1 102 is incorporated. In sealed communication with the second opening 1212 of the moulded body portion 1206 is a diaphragm 1216. Gas is unable to escape from, or enter into, the pressure pad 1 108 via the tactile feedback module 1122.

In an initial state, the diaphragm 1216 is substantially flat. In the initial state, the diaphragm 1216 is substantially perpendicular to the diameter of the second opening 1212 of the moulded body portion 1206. The diaphragm is constituted of a semi flexible material. The material is non-porous such that fluid is unable to pass therethrough. When the pressure within the pressure pad increases due to an applied touch input, the diaphragm 1216 is configured to expand in a direction substantially away from the main body portion 1206. The diaphragm 1216 is elastic. As such, when the gas pressure within the pressure pad 1 108 is subsequently reduced, the membrane returns to its initial state.

The switch portion 1204 of the tactile feedback module 1122 comprises a dome switch 1218 and a base portion 1220. The dome switch 1218 is mounted on the base portion 1220. The base portion 1220 may be mounted on the PCB 1 123. Alternatively, the base portion 1220 may be constituted by a part of the housing of the device in which the touch sensitive display device is housed. Alternatively, the base portion may be constituted by the PCB 1123.

The dome switch 1218 has two states: an initial state and an activated state. In Figure 12A, the dome switch 1218 is in its initial state. In the initial state, the dome switch 1218 is substantially dome-shaped. In the initial state, an input section 1222 of the dome switch 1218 is spaced by a distance from the base portion 1220. The transition from the initial state to the activated stated is effected by the application of a force, in excess of a switching threshold, being applied to the input section 1222 in a direction substantially towards the base portion 1220. In the activated state, as is shown in Figure 12B, the dome switch 1218 is collapsed due to the incident force. In the activated state, the input section 1222 is in contact, or nearly in contact, with the base portion 1220.

The input section 1222 of the dome switch 1218 is in communication with the diaphragm 1216. In its initial state, the dome switch 1218 resists the expansion of the diaphragm 1216. In its activated state, the dome switch 1218 allows an amount of expansion of the diaphragm 1216. The dome switch 1218 transitions from its initial state to its activated state when a touch input applied to the touch sensitive layer 1106 causes an expansion force exerted by diaphragm 1216 on the dome switch 1218 to exceed the switching threshold of the dome switch 1218.

In Figure 12A, no touch input, or a touch input causing a force on the dome switch 1218 below the switching threshold, is being applied to the outer surface 1104 of the touch sensitive panel 1106. When a touch input causing an expansion force below the switching threshold is applied by the user, the dome switch 1218 prevents any substantial expansion of the diaphragm 1216.

In Figure 12B, the force of the applied touch input causes the force exerted by the diaphragm 1216 to pass from below to above the switching threshold of the dome switch 1218. Consequently, the dome switch 1218 collapses, thereby switching to its activated state. As such, the input section 1222 of the dome

switch 1218 suddenly moves away from the diaphragm 1216 towards the base portion 1220. The diaphragm 1216 suddenly expands to fill the space vacated by input section 1222 of the dome switch 1218.

The sudden expansion of the diaphragm 1216 causes a sudden increase in the volume of the gas within the pressure pad 1 108. Consequently, the gas pressure within the pressure pad 1108 is suddenly reduced. As discussed above, the user will experience this as a sudden movement of the touch sensitive panel 1106 away from their finger or stylus etc.

When the force due to the touch input is reduced, the expansion force exerted by the diaphragm 1216 is also reduced. The dome switch transitions from its activated state to its initial state, when the expansion force exerted by the diaphragm 1216 on the input section 1222 of the dome switch 1218 passes from above to below the switching threshold of the dome switch 1218. This transition results in a force being applied by the dome switch 1218 on the diaphragm 1216. The force causes the diaphragm 1216 suddenly to return, or substantially to return, to it initial unexpanded state. This, in turn, causes a sudden reduction in volume of gas within the pressure pad 1 108, and thus an increase in gas pressure. As discussed above, this sudden increase in pressure results in slight movement of the touch sensitive panel 1108 towards the user's finger.

It will be understood that other arrangements may be suitable also for use in the tactile feedback module 1122. For example, the diaphragm 1216 may be replaced by a rigid extension member that is arranged to extend retractably from the moulded body portion 1206 in response to an increase in gas pressure within the pressure pad 1 108, thereby decreasing the pressure of the gas within the pressure pad 1108. It will be understood also that any suitable type of dome switch 1218 may be used.

In alternative embodiments, the tactile feedback module 1122 is in electrical communication with the pressure sensor 1124. In such embodiments, the tactile feedback module comprises an electrically controlled tactile feedback mechanism configured to reduce suddenly the pressure within pressure pad

1 108, in response to receiving from the pressure sensor 1124 signals indicating that the gas pressure within the pressure pad 1108 has passed from below to

above a feedback threshold. The electrically controlled tactile feedback module 1 122 is controlled also to increase suddenly the gas pressure within the pressure pad 1124 in response to receiving signals from the pressure sensor 1124 indication that the gas pressure has passed from above to the below the feedback threshold.

According to embodiments as described in the above paragraph, the tactile feedback module 1122 may comprise a clamping means. The clamping means may be controlled in response to signals received from the pressure sensor, to compress and uncompress the branch section, thereby to reduce and increase the volume of the gas within the pressure pad. In embodiments such as this, the second end 1 120 of the branch tube is closed.

According to alternative embodiments in which the tactile feedback module 1122 and the pressure sensor 1 124 are in electrical communication, the electrically controlled tactile feedback module 1122 may comprise a piston, controlled in response to signals received from the pressure sensor 1 124 to increase and decrease the volume of gas within the pressure pad 1 108.

It will be understood that, according to some embodiments, the pressure pad 1108 may include the tactile feedback module 1122 described with reference to Figures 11 and 12 but not the pressure sensor 1124 for determining the pressure within the pressure pad 1108. The force due to the applied touch input may instead be determined, if required, using another suitable means.

According to alternative embodiments, the display panel is not included. Such embodiments may be used, for example, in touch pads and the like.

It should be realised that the foregoing embodiments should not be construed as limiting. Other variations and modifications will be apparent to persons skilled in the art upon reading the present application. Moreover, the disclosure of the present application should be understood to include any novel features or any novel combination of features either explicitly or implicitly disclosed herein or any generalisation thereof and during the prosecution of the present application or of any application derived therefrom, new claims may be formulated to cover any such features and/or combination of such features.