WO2019156610A1

WO2019156610A1 - Touch sensing apparatus and method of assembly thereof

Info

Publication number: WO2019156610A1
Application number: PCT/SE2019/050076
Authority: WO
Inventors: Mattias KRUS; Daniel Skagmo
Original assignee: Flatfrog Laboratories Ab
Priority date: 2018-02-06
Filing date: 2019-01-31
Publication date: 2019-08-15
Also published as: CN110119229A

Abstract

A method of operating a touch sensing apparatus is provided. The touch sensing apparatus comprises a panel that defines a touch surface, a plurality of light emitters and detectors arranged along a perimeter of the panel and the light emitters are arranged to emit a respective beam of emitted light above the touch surface, and the light emitters are arranged to receive detection light from the emitted light. The method further comprises emitting a beam of light from at least one light emitter. Another step of the method is detecting the emitted light at one or more detectors. Yet another step of the method is determining a distribution of blocked light by at least one mountable light blocking component on the touch sensing apparatus between the at least one light emitter and the one or more detectors.

Description

Touch sensing apparatus and method of assembly thereof

The present invention relates to a touch sensing apparatus and a method of assembly thereof.

Some touch sensitive apparatus are known as‘above surface optical touch systems’. These touch sensitive apparatuses have a set of optical emitters which are arranged around the periphery of a touch surface to emit light that is reflected to travel and travel above the touch surface. A set of light detectors are also arranged around the periphery of the touch surface to receive light from the set of emitters from above the touch surface. An object that touches the touch surface will attenuate the light on one or more propagation paths of the light and cause a change in the light received by one or more of the detectors. The location (coordinates), shape or area of the object may be determined by analysing the received light at the detectors.

A problem with some touch sensitive apparatuses is that a variety of the internal components are fragile and easily damaged. In some arrangements assembly requires alignment between of cumbersome components such as a large glass panel, which can be difficult and costly.

Incorrect assembly can lead to misalignment and consequential signal loss or even damage to the components. Such precise alignment may be difficult to achieve in mass production. The use of collimated light, or light reflected by means of specular reflection, also adds to this complexity, which in turn results in a more expensive and less compact system. Furthermore, to reduce system cost, it may be desirable to minimize the number of electro-optical components.

Embodiments of the present invention aim to address the aforementioned problems.

In a first aspect there is provided a method of operating a touch sensing apparatus, the touch sensing apparatus comprising a panel that defines a touch surface, a plurality of light emitters and detectors arranged along a perimeter of the panel and the light emitters are arranged to emit a respective beam of emitted light above the touch surface, and the light emitters are arranged to receive detection light from the emitted light, the method comprising: emitting a beam of light from at least one light emitter; detecting the emitted light at one or more detectors; and determining a distribution of blocked light by at least one mountable light blocking component on the touch sensing apparatus between the at least one light emitter and the one or more detectors.

This means that at least part of the touch sensing apparatus can be used to self-diagnose whether light blocking components have been installed correctly.

Preferably the at least one light blocking component is at least one spacer mounted between the panel and a housing to limit the movement of the panel with respect to the plurality of light emitters and detectors. The spacers are mountable around the periphery of the panel and their location and orientation can be checked.

Preferably the method comprises comparing the determined distribution of blocked light with a predetermined component light blocking pattern. Preferably the method comprises generating a predetermined distribution of blocked light on the basis of a predetermined distribution of light blocking components on the touch sensing apparatus. Preferably the method comprises determining a difference between a determining distribution of blocked light and a predetermined component light blocking pattern. Preferably the method comprises generating a component mounting error information based on the determined difference. This means that the installation of the light blocking component can be blocked and checked. If the installation is incorrect, then error information is generated which can be reviewed during manufacture.

Preferably the method comprises generating an alert based on the component mounting error information. Preferably the method comprises displaying the alert on a display unit connectively coupled to the touch sensing apparatus. Preferably the method comprises displaying the alert on a terminal connectively coupled to the touch sensing apparatus. This means the user can identify where the error is. If the error is displayed on a display unit associated with the touch sensing apparatus, the display unit can visually indicate on the display unit the location of the component associated with the error information.

Preferably the method comprises mounting additional light blocking components around the perimeter of the panel on the basis of the alert. Preferably the method comprises mounting a plurality of light blocking components around the perimeter of the panel. This means remedial action can be taken in manufacture to rectify the assembly error of the light blocking component.

Preferably the method comprises operating in a first mode wherein the steps of emitting a beam of light from at least one light emitter and detecting the emitted light at one or more detectors use a first region of interest and operating in a second mode wherein the steps of emitting a beam of light from at least one light emitter and detecting the emitted light at one or more detectors use a second region of interest and the first region of interest is smaller than the second region of interest. Preferably the operating of the first mode is a normal mode of operation and the operating of the second mode is a checking mode for assembly of the touch sensing apparatus. Preferably operating the second mode of operation is activated on the basis of an installation signal. This means that the touch sensing apparatus can be operated in a test mode during assembly which can be used to check the installation of the light blocking components. The test mode can be deactivated once the touch sensing apparatus once the touch sensing apparatus passes the quality control checks. This means that the processing of the detection signals will be less because the first region of interest will be smaller during normal operation mode than the second region of interest used in the test mode.

In a second aspect there is provided a non-transitory computer-readable storage medium storing instructions that, if executed by a processor of a controller, cause the processor to carry out the aforementioned method. In a third aspect there is provided a touch sensing apparatus comprising: a panel that defines a touch surface; a plurality of light emitters and detectors arranged along a perimeter of the panel and the light emitters are arranged to emit a respective beam of emitted light above the touch surface, and the light emitters are arranged to receive detection light from the emitted light; and a controller configured to operate in a first mode wherein the plurality of light emitters and detectors use a first region of interest and to operate in a second mode wherein the wherein the plurality of light emitters and detectors use a second region of interest wherein the first region of interest is smaller than the second region of interest; wherein at least one mountable light blocking component position around the perimeter for the panel is detectable in the second mode and not in the first mode.

In a fourth aspect there is provided a testing apparatus for checking component assembly of a touch sensing apparatus, the touch sensing apparatus comprising a panel that defines a touch surface, a plurality of light emitters and detectors arranged along a perimeter of the panel and the light emitters are arranged to emit a respective beam of emitted light above the touch surface, and the light emitters are arranged to receive detection light from the emitted light, and a housing on which the plurality of light emitters and detectors are mountable; the testing apparatus comprising: an interface for receiving information from the touch sensing apparatus in respect of detection of emitted light at one or more detectors; and a processor for determining a distribution of where light is blocked by at least one light blocking component between the at least one light emitter and the one or more detectors.

Various other aspects and further embodiments are also described in the following detailed description and in the attached claims with reference to the accompanying drawings, in which:

Figure 1 shows a schematic perspective exploded view of the touch sensing apparatus;

Figure 2 shows a schematic cross section of the touch sensing apparatus; Figures 3 and 4 show an enlarged cross sectional side view of the touch sensing apparatus;

Figure 5 also shows a plan view schematic representation of the touch sensing apparatus;

Figure 6 shows a close up schematic representation of the touch sensing apparatus;

Figure 7 is a flow diagram of the method according to some embodiments; Figure 8 shows a flow diagram according to an embodiment; and

Figure 9 is a flow diagram of the method according to some embodiments.

Figure 1 shows a schematic perspective exploded view of the touch sensing apparatus 100. For the purposes of clarity, the exploded perspective view in Figure 1 shows the separate components side by side, but the dotted line of a normal axis N-N represents the order of how the components stack together. Only the main components of the housing 118, the light transmissive panel 102 and the display 130 are shown in Figure 1 .

Turning to Figure 2, other components of the touch sensing apparatus 100 will now be discussed in more depth according to some embodiments. Figure 2 shows a schematic cross section of the touch sensing apparatus 100 along a plane Pc-Pc as indicated in Figure 1 .

The touch sensing apparatus 100 comprises a light transmissive panel 102 that defines a touch surface 104. In some embodiments the light transmissive panel 102 is located above the display 130 and permits light generated by the display 130 to propagate therethrough. However in other embodiments the light transmissive panel 102 can comprise light blocking material and does not permit the transmission of light therethrough. For example, the touch sensing apparatus 100, can be a trackpad or another touch interface which is remote from the display unit 130. Hereinafter the term“panel” 102 will be used to describe either a light transmissive panel 102 or a solid, opaque panel 102.

A plurality of light emitters 106a and detectors 106b are arranged along a perimeter 108 of the panel 102. Figure 5 also shows a plan view schematic representation of the touch sensing apparatus 100. Figure 5 shows the light emitters 106a and the detectors 106a distributed around the perimeter 108 of the panel 102. The light emitters 106a are arranged to emit a respective beam of emitted light LE above the touch surface 104. Similarly the light detectors 106b are arranged to detect a respective beam of detected light LD above the touch surface 104. The emitted light beam LE and the detected light beam LD are represented schematically as a two headed bold arrow. As shown in Figure 2, the touch surface 104 extends along a plane PA - PA which is only shown from the side of the touch sensing apparatus 100. PA - PA is also shown in Figure 1 . The touch surface 104 has a normal axis N-N directed towards a user performing touch operations on the touch surface 104, the emitted light LE travels along the plane PA - PA but at a certain distance from the touch surface 104 in the direction of the normal axis N-N, as schematically illustrated with respect to light beam LE, LD in e.g. Figure 2. As shown in Figure 2, the respective light beams LE, LD are transmitted at a height above the panel 102. The height of transmission is determined by the respective relative height of the light emitters 106a and associated optics with the panel 102.

Light LE, LD, can thus travel across the touch surface 104, between opposite sides thereof, without being reflected inside the panel 102 itself (assuming the panel 102 is a light transmissive panel). The light detectors 106b are arranged to receive detection light LD from the emitted light LE. Figure 2 illustrates a section of the touch sensing apparatus 100 adjacent the perimeter 108 of the light transmissive panel 102. In this section, the emitters and detectors 106a, 106b, are shown in the same view, as well as the emitted and detected light LE, LD, for clarity of presentation. In some embodiments, the plurality of light emitters and detectors 106a, 106b, are arranged above the touch surface 104 and are connected to a substrate 1 10 extending in a plane PB-PB parallel with a normal axis N-N of a plane PA - PA in which the light transmissive panel extends. In other embodiments the plurality of light emitters and detectors 106a, 106b are located below the touch surface 104 and / or the panel 102 and optical elements are used to guide the light beams LE, LD around the panel 102. For example, Figure 4 shows such an arrangement where the light emitters and detectors 106a, 106b are mounted below the panel 102. Figure 4 will be discussed in more depth below. Plane PB-PB is also shown in Figure 1 . In some embodiments the substrate 1 10 is a printed circuit board (PCB) for mounting components thereto.

By having the substrate 1 10 extending in parallel with the normal axis N-N it is provided for conveniently arranging the plurality of emitters and detectors 106a, 106b, above or below the touch surface 104 to achieve a compact footprint in the direction of the plane PA - PA and / or PB - PB of the touch sensing apparatus 100 around the perimeter 108 while achieving a direct light path of the emitted or detected light LE, LD, above and across and touch surface 104. Thus, optionally the emitted light LE does not have to be reflected in order to diffusively spread above and across the touch surface 104, and a detector 106b may directly receive detection light LD by being correspondingly positioned above the touch surface 104 at an opposite position anywhere around the perimeter 108. Alternatively, the emitted light LE is reflected in order to be guided above and across the touch surface 104, and a detector 106b may similarly receive reflected detection light LD.

The amount of available light that can be utilized for the detection and characterization of an object touching the touch surface 104 can thus be maximized, and the signal to noise ratio can be improved. The touch sensing apparatus 100 may comprise a sealing window 1 16 as illustrated in Figure 2, shielding the emitters and detectors 106a, 106b, from the outside. The emitted and detected light LE, LD may thus only have to propagate through the sealing window 1 16 along the light path between the emitters and detectors 106a, 106b. The sealing window 126 provides sealing around the perimeter 108 of the light transmissive panel 102 and protects the emitters and detectors 106a, 106b and the display.

As mentioned above, the substrate 1 10 extends in the plane PB-PB being parallel with the normal axis N-N and the emitters and detectors 106a, 106b, arranged above or below the touch surface 104. This provides for a less complex alignment to maximize the detection performance of the touch sensing apparatus 100. The position of the substrate 1 10 in the direction of the normal axis N-N can be accurately varied to achieve optical alignment with respect to the emitters and detectors 106a, 106b. The ability to achieve an accurate positioning of the substrate 1 10, and consequently the emitters and detectors 106a, 106b, attached thereto, is also due to the increased accuracy by which the dimensions of the substrate 1 10 can be defined along the direction of the substrate 110 aligned with the normal axis N-N in Figure 2. In some embodiments, the substrate 1 10 is elongated and extends in a longitudinal direction (for example as shown in Figures 1 and 5) around the perimeter 108 of the light transmissive panel 102, and it has a short-side extending in parallel with the normal axis N-N.

The short-side of the substrate 110, illustrated in the cross-sectional view of Figure 2, in some embodiments may be manufactured to smaller tolerances. This may be achieved by aligning the short side with the normal axis N-N and the tolerances for the alignment of the emitters and detectors 106a, 106b, along the normal axis N-N can be improved. The alignment of the substrate 110 and the plurality of the light emitters and detectors 106a, 106b can thus be both improved, and facilitated as discussed above. The latter advantage also provides for facilitated and less costly mass production of the touch sensing apparatus 100 and the various touch base display systems in which it may be implemented.

In some embodiments, the substrate 1 10 may be mounted at least partly above the touch surface 104, whereby the plurality of light emitters and detectors 106a, 106b, are connected to a portion 114 of the substrate extending above the touch surface 104. The upper portion 114 of the substrate 110 further provides a more robust alignment of the emitters and detectors 106a, 106b, relative to the light transmissive panel 102, by being directly joined to the substrate 1 10, and thereby simultaneously arranged above the touch surface 104. Alternatively or additionally in some embodiments the emitters and detectors 106a, 106b may be connected to the substrate 1 10 via connection elements (not shown) extending between the substrate 1 10 and to a position above the touch surface 104. The substrate 1 10 may be fixed to a housing 118 mounted around the perimeter 108 of the panel 102, as schematically illustrated in Figures 1 to 5. By directly joining the substrate 1 10 to the housing 1 18 provided around the perimeter 108, the assembly of the touch sensing apparatus 100 may be further facilitated, as the amount of components can be kept at a minimum.

For example, the substrate 110 can be accurately fixed in relation to the housing 1 18, due to the small tolerances possible in the direction of the substrate 1 10 aligned in parallel with the normal axis N-N in Fig. 1 , as discussed above. The housing 1 18 may for example comprise a cavity 120, as discussed further below, being precisely dimensioned to accommodate the width of the substrate 1 10 along the plane PB-PB, i.e. the short-side of the substrate 1 10. Then, accurate positioning of the emitters and detectors 106a, 106b, in relation to the light transmissive panel 102 is possible as the housing 1 18 is mounted around the perimeter 108 thereof. The housing 1 18 may extend substantially in the plane PB-PB parallel with the normal axis N-N, as with the substrate 1 10, to achieve a compact mounting around the perimeter 108.

Figure 2 only shows the touch sensing apparatus 100 in the plane Pc as shown in Figure 1 . In some embodiments the housing 1 18 envelops the light transmissive panel 102 on all sides around the perimeter 108 of the light transmissive panel 102.

Having the substrate 1 10 fixed to the housing 1 18 allows also for having the housing 1 18 wired as an electrical ground reference layer of the substrate 1 10.

The housing 1 18 may be arranged to at least partly enclose edges 122 of the light transmissive panel 102, as shown in the example of Figure 1 . This provides for further increasing the robustness of the touch sensing apparatus 100, and improving the accuracy of the alignment of the emitters and detectors 106a, 106b, in relation to the light transmissive panel 102 since the housing 1 18, having the emitters and detectors 106a, 106b, fixed thereto, may also be directly supporting the light transmissive panel 102 around the perimeter 108. The housing 1 18 may comprise a slot (not shown) in which the light transmissive panel 102 is fitted around the perimeter 108.

The housing 1 18 may comprise fixing elements 124 configured to attach the housing 1 18 to a display unit 130. The display unit 130 may comprise a display support 126 and a display panel 128, which collectively is referred to as a display unit 130 in the present disclosure. Having the housing 1 18 attachable to the display unit 130, by fixing elements 124, advantageously provides for further facilitating the assembly of the touch sensing apparatus 100 to a display unit 130, since the housing 1 18 can be directly joined to the latter. Alignment is thus facilitated, due to the minimum amount of components needing such alignment to each other.

If a touch sensing apparatus 100 is to be a large size, then the panel 102 can be a large heavy component. It has been noted that movement of the panel 102 with respect to other components such as the housing 1 18 or the substrate 1 10 can adversely affect the performance and lifetime of the touch sensing apparatus 100. In particular the panel 102 can abut up against and exert a force against the substrate 110. This can misalign the optical components such as the light emitters and detectors 106a, 106b mounted on the substrate 1 10. Furthermore if the touch sensing apparatus experience a significant force, then the panel 102 can damage and / or break the substrate 110 or other components.

Figures 3 and 4 will now be discussed in reference to embodiments which limit the relative movement between the panel 102 and the light emitters and detectors 106a, 106b.

Figures 3 and 4 show an enlarged cross sectional side view of the apparatus 100 as shown in Figure 2. Figure 3 is the same as Figure 2, except a spacer 300 is shown between the housing 118 and the panel 102. The arrangement in Figure 3, and in particular the spacer 300, is part of the embodiment as shown in reference to Figure 2. However, for the purposes of clarity, the spacer 300 is not shown in Figure 2. The spacer 300 will now be discussed in more detail. The spacer 300 is mounted between the housing 1 18 and the panel 102 and is in mechanical engagement between the panel 102 and the housing 1 18. In this way, force exerted by the panel 102 is transmitted through the spacer 300 to the housing 1 18. This means that the panel 102 does not engage with the substrate 1 10 or other components of the touch sensing apparatus 100. Accordingly the spacer 300 protects the substrate 1 10 and other components from physical shocks and movement of the panel 102. The spacer 300 dampens the vibrations experienced by the panel 102 being transferred to the housing 1 18 and the internal components including the substrate 1 10.

The edge 122 of the panel 102 abuts a first surface 302 the spacer 300. The panel 102 as shown in Figure 3, the panel 102 rests against the spacer 300. The friction between the first surface 302 and the edge 122 is sufficient to prevent relative movement therebetween. As shown in Figure 5, there are a plurality of spacers 300 located around the perimeter 108 of the panel 102. The spacers 300 are mounted such that the components do not block the light beams LE, LD during normal operation of the touch sensing apparatus 100. The spacers 300 are orientated to minimize blocking the light beams LE, LD in laterally in plane PA - PA and vertically in plane PB - PB. Accordingly during assembly the panel 102 is slid into position. During this process, the panel 102 can be wedged between spacers 300 to provide a friction fit. In some embodiments, there is at least one spacer 300 along each side of the panel 102. This means that there is always a spacer 300 between the housing 118 and the panel 102 limiting movement in every direction along the plane PA - PA. In other embodiments there are fewer spacers 300. For example, in a less preferable embodiment there is a single spacer 300 to limit movement of the panel 102. In another embodiment there are four spacers 300 located at each corner of panel 102.

In other embodiments the spacer 300 is coupled to the panel 102 with fastenings (not shown). The spacer 300 can be pre-mounted to the panel 102 before the panel 102 is slid into position during assembly. Pre-mounting the spacer 300 to the edge 122 can assist in aligning of the components during assembly. The spacer 300 can be mounted to the panel 102 with any suitable fastening such as screws, clips, latches, hooks and / or glue. Additionally or alternatively the spacer 300 can be extruded along the edge 122 of the panel. Physically fixing the spacer 300 to the edge 122 may be unsightly, however the fixings and the spacer 300 will may not be visible in normal operation or impact on the operational touch surface 104. The housing 118 comprises an overlapping portion 304 to protect the components e.g. the light emitters and detectors 106a, 106b. The overlapping portion 304 covers the edge 122 of the panel 102 and the spacer 300.

To aid engagement between the panel 102 and the spacer 300, the spacer 300 in some embodiments comprises a flange 314. The flange 314 extends and projects over the substrate 1 10. In this way, vibrations experienced by the panel 102 do not cause the panel 102 to damage the substrate 1 10 The flange 314 and / or the first surface 302 can comprise a recess for receiving the panel 102. The recess (not shown) of the spacer 300 in the first surface 302 can engage the edge 122, the touch surface 102 and / or a bottom surface 320 of the panel 102.

Similarly, the spacer 300 is mounted to the housing 1 18. In some embodiments a second surface 308 of the spacer 300 abuts against an interior surface 306 of the housing 1 18. The spacer 300 is also kept in position by virtue of a friction fit between the second surface 308 and the interior surface 306. For example, the panel 102 is wedged between the housing 1 18 and one or more spacers 300. Alternatively or additionally, the spacer 300 is mounted to the housing 118 in other ways.

The housing 1 18 comprises a recess 310 for receiving the spacer 300. The recess 310 is a reciprocal shape to the spacer 300. In some embodiments, the recess 310 is slightly larger than the dimensions of the spacer 300. In this way the spacer 300 fits snugly in the recess 310 and is held in place with a friction fit. The recess 310 alternatively may be larger and the spacer 300 rests on a projecting shoulder portion (not shown). Additionally or alternatively the spacer 300 is mounted to the housing 1 18 with a fixing such as a screw 312. The screw 312 may thread into a hole in the housing 1 18 and a blind bore in the spacer 300. The spacer 300 can be mounted to the housing 1 18 with any other suitable fastener such as a clip, latch, hook. In yet another embodiment the spacer comprises an open bore and fastener 312 threads through the open bore of the spacer 300 and into a reciprocal blind bore (not shown) in the panel 102.

Figure 3 shows a cross section of the spacer 300. The spacer 300 can be substantially cylindrical in shape. Alternatively the spacer 300 is cuboid in shape and extends longitudinally along plane PB - PB to increase the mechanical engagement between the edge 122 and the first surface 302 of the spacer 300.

Figure 3 shows the substrate 1 10 being positioned above and below the spacer 300. In this way, the substrate 1 10 comprises a reciprocal hole 316 for receiving the spacer 300. The spacer 300 projects through the hole 316 of the substrate and does not transmit force from the panel 102 to the substrate 1 10. The hole 316 can be large enough so that the spacer 300 does not have any mechanical engagement between the spacer 300. In this case, although not shown, the substrate 1 10 can be immediately adjacent to and abut the interior surface 306 of the housing 1 18.

In some embodiments the hole 316 of the substrate 1 10 is an open bore drilled through the substrate 1 10. In other embodiments the hole 316 is a slot (not shown) wherein the slot extends to the edge of the substrate 110. In this way, the substrate can be slid around the spacer 300 during assembly.

In other embodiments, the substrate 1 10 is coupled to the spacer 300 such that no relative movement occurs between the spacer 300 and the substrate 110. In this way, the substrate 1 10 will move, if the spacer 300 experiences movement. However the substrate is mounted on the spacer 300 at a distance from the interior surface 306 of the housing 1 18. In some embodiments, the substrate 1 10 is mounted immediately under the flange 314. Accordingly the spacer 300 and substrate 1 10 are fixed together and move together. A gap 318 between the substrate 1 10 and the interior surface 306 of the housing 1 18 means that the substrate 1 10 does not come in to physical engagement with the housing 1 18 when the spacer 300 and the substrate 110 move towards the housing 1 18.

In some embodiments, the spacer 300 as shown in Figure 3 is mounted below the light emitters and detectors 106a, 106b.

Turning to Figure 4, another embodiment will not be discussed. Figure 4 is a cross sectional schematic side view of the touch sensing apparatus along the plane P_c. Figure 4 is the same as Figure 3 except that the orientation, shape and location of some of the components of the touch sensing apparatus 100 have been changed. The same reference number will be used for the same features. All the features as discussed in reference to the embodiments shown in Figure 3 are also applicable to the embodiments shown in reference to Figure 4.

The plurality of light emitters and detectors 106a, 106b are positioned below the panel 102. This means that the light beams LE, LD must be guided around the panel 102. This is achieved with a reflector 400 mounted on the interior surface 306 of the housing 1 18.

Similar to the previous embodiments, the spacer 300 is mechanically coupled between the panel 102 and the housing 1 18. The spacer 300 comprises a lip 402 which abuts the bottom surface 320 of the panel 102. The lip 402 means that at least two perpendicular surfaces of the panel 102 are in mechanical engagement with the spacer 300. This means that the spacer 300 limits movement of the panel with respect to the light emitters and detectors 106a, 106b in two different directions. Indeed as shown in Figure 4, the spacer 300 limits the movement of the panel 102 in the lateral direction along the plane PA - PA and downwardly in the place PB - PB. The spacer 300 may comprise another similar lip (not shown) which engages with the touch surface 104. In this way the spacer 300 will limit the movement of the panel 102 upwardly and downwardly in plane PB - PB.

In Figure 4, the spacer 300 abuts against the interior surface 306 of the housing 1 18 and there is no reciprocal recess. Instead friction or the aformentioned fastening options are used to keep the spacer 300 fixed with respect to the housing 1 18.

As can be seen from Figure 4, the light beams L_E, L_D pass through the spacer 300. The spacer 300 is made from a light blocking material and is positioned so that the light beams L_E, L_D are not blocked during normal operation. The spacer 300 may be positioned in front or behind of the light beams L_E, L_D SO that the spacer 300 does not block the light. Alternatively the spacer 300 may comprise a hole or a transparent element for allowing the light beams passing through the middle of the spacer 300.

In some embodiments, the spacer 300 can be mounted to a plurality of interior surfaces of the housing 1 18. For example, the spacer 300 can be mounted to the vertical interior surface 306 and the underside surface 404 of the overlapping portion 304. Alternatively a plurality of spacers 300 can be used to each limit the movement of the panel 102 in a particular direction.

The spacers 300 may be resiliently deformable. In this way the spacers 300 have a shock absorbing quality to dampend vibrations. In some embodiments, the spacers 300 are made from an elastic material such as rubber, thermopolymer elastomer (TPE), foam, silicone, or any other suitable material. The spacers 300 are made from a light blocking material and may be colour black to absorb emitted light.

A method of manufacture of the touch sensing apparatus 100 will now be described in reference to Figure 8. Figure 8 shows a flow diagram according to an embodiment. The touch sensing apparatus 100 is assembled according to the following steps. A plurality of light emitters and detectors 106a, 106b are mounted to a housing 118 as shown in step 800. The housing 118 is attached around a perimeter 108 of a panel 102, wherein the panel defines a touch surface 104 as shown in step 802. At least one spacer 300 is mounted between the panel 102 and the housing 118 to limit the movement of the panel 102 with respect to the plurality of light emitters and detectors 106a, 106b as shown in step 804. In some embodiments the steps as shown in Figure 8 can be take in a different order. For example optionally the spacer 300 can be mounted to either the housing 118 or the panel 102 before attaching the housing 118 to the panel 102.

One of the problems in assembly of the components of the touch sensing apparatus 100 is that one or more components may be omitted or incorrectly installed. Some components such as the aforementioned spacers are not light emitting or detecting components. This means if they are omitted during assembly, the touch sensing apparatus may work when tested during quality control, but may be returned for repair later one because the component was missing. Visual inspection on the assembly line of the non-light emitting components may not identify missing or incorrectly installed components.

In some embodiments, a method of operating the touch sensing apparatus 100 is provided for checking installation of light blocking components such as spacers 300 as mentioned previously with respect to the embodiments above.

It is possible to use the light emitters and detectors 106a, 106b to check the installation of light blocking components located on the perimeter 108 of the panel 102. Figure 5 shows a schematic plan representation of a plurality of spacers 300 located around the perimeter 108 of the panel 102. Figure 5 is an example of a predetermined pattern of spacers 300 around the perimeter 108 of the panel 102. The predetermined pattern of spacers 300 is determined on the size, weight, orientation of the touch sensing apparatus 100. The predetermined pattern of spacers 300 can change depending on the parameters of different models of touch sensing apparatus 100. In this way, each predetermined pattern of spacers 300 is a mask that can be used to check correct installation of orientation of the spacers 300 for each touch sensing apparatus during a quality control stage in manufacture. Whilst the embodiments described in reference to Figures 5 to 7 are applicable to spacers 300, the method can be applied to checking the correct installation of any light blocking component mountable around the perimeter 108 of the panel 102. For example other light blocking components may be seals, gaskets, fasteners, or any other light blocking component.

Figure 5 shows a spacer 500 which is incorrectly installed on the perimeter 108 of the panel 102. For example spacer 500 has been omitted or is mounted a few millimeters from the intended mounting location. This means that the pattern of spacers 300 around the perimeter 108 of the panel 102 is different from the predetermined pattern of spacers 300.

The touch sensing apparatus 100 used to check the installation of light blocking components will now be described in reference to Figure 6. Figure 6 shows a close up schematic representation of the touch sensing apparatus 100 as shown by the dotted line in Figure 5. The arrangement of the panel 102, the housing 1 18, and the substrate 110 extends around the entire perimeter 108 of the touch sensing apparatus 100. Figure 6 also shows a schematic representation of the processors and controllers which operate the touch sensing apparatus 100.

Figure 6 shows an example pair of a light emitter 106a and a light detector 106b. The light emitter 106a and the detector 106b are mounted on a substrate 1 10 which is mounted on and abuts the housing 1 18. Adjacent to the light emitter and detector 106a, 106b is a first spacer 300 and a second spacer 500.

Figure 6 shows a first region of interest 600. The first region of interest is defined as the angular range, both in the Q (theta) (which is the angle of the light from the normal N-N of the plane PA-PA of the panel 102) and f (phi) (which is the angle of the light from the normal of the edge 122 of the panel 102 and in the plane P_A-P_A of the panel 102).

A selection of both Q and f are used for the emitted and detected light L_E, L_D travelling in or on top of the panel 102 from which the system is configured to derive a touch signal. This range may be chosen for optimal touch resolution and to exclude contamination noise. In some embodiments a touch-sensing system in normal operation may use the first region of interest 600 of light between 40^° to 90^° for Q, although preferably between 50^° to 75^°, and a range of ±75^° for f. In this way the total angle of f is 150^° for the first region of interest 600 as shown in Figure 6.

Figure 6 also shows a larger second region of interest 606 which comprises additional regions of interest 602, 604 and the first region of interest 600. The second region of interest 606 represents light being emitted and detected over a greater angle of f than in the first region of interest 600. This means that the second field of interest 606 is larger than the first region of interest 600. In particular, the second field of interest 606 is a range of ±80^° for f. In this way the total angle of f is 160^° for the second region of interest 606 as shown in Figure 6. Advantageously the second region of interest 606 uses a slightly greater f value to perform checking of the installation of light blocking components such as spacers 300. During normal operation of the touch sensing apparatus 100 a value of f between 75^° to 80^° is not used due to errors in the detected signal. However using a range of f between 75^° to 80^° is acceptable during assembly and quality control for checking the presence of mountable light blocking components 300 along the perimeter 108 of the panel 102.

Optionally the touch sensing system 610 may operate in one of the two modes; a first mode using a first region of interest 600; and a second mode using a second region of interest 606. However in some embodiments, the touch sensing system 610 always operates in one mode using the second region of interest 606 where light blocking components 300 mountable around the perimeter 108 of the panel 102 are always detectable.

As is illustrated in Figure 6, the touch-sensing system 610 may include an activation controller 608 which is connected to selectively control or modulate the activation of the light emitters 106a and, possibly, a touch controller 612 to selectively detect or provide readout of data from the detectors 106b. The touch sensing system 610 comprises both the touch sensing apparatus 100 and the display unit 130. The activation controller 608 and touch controller 612 may also be implemented as a single controller 614 for controlling the touch-sensing system 610. Depending on implementation, the emitters 106a and/or detectors 106b may be activated in sequence or concurrently, e.g. as disclosed in WO2010/064983. One or both of the touch controller 612 and the activation controller 608 may be at least partially implemented by software stored in a memory unit 616 and executed by a processing unit.

The touch sensing system 610 comprises a main controller 618. The main controller 618 may optionally be connected to a display controller 620 which is configured to generate a user interface on a display unit 130 based on control signals from the main controller 618. The main controller 618 is thereby operable to coordinate the user interface on the display device 130 with the data from the touch detection system, e.g. touch data from the touch controller 612.

As used herein, a "light emitter" or "emitter" may be any type of opto-electronic device capable of emitting radiation in a desired wavelength range, for example a diode laser, a VCSEL (vertical- cavity surface-emitting laser), an LED (light- emitting diode), electo or opto-lumninisent OLED, display pixel, quantum dot, etc. A light emitter may also be formed by the end of an optical fiber.

The main controller 618 may be configured to process the projection signals so as to determine a property of the touching objects, such as a position (e.g. in a x,y coordinate system), a shape, or an area. This determination may involve a straight-forward triangulation based on the attenuated detection lines, e.g. as disclosed in US7432893 and WO2010/015408, or a more advanced processing to recreate a distribution of attenuation values. The attenuation pattern may be generated e.g. by any available algorithm for image reconstruction based on projection signal values, including tomographic reconstruction methods such as Filtered Back Projection, FFT-based algorithms, ART (Algebraic Reconstruction Technique), SART (Simultaneous Algebraic Reconstruction Technique), etc. Alternatively, the attenuation pattern may be generated by adapting one or more basis functions and/or by statistical methods such as Bayesian inversion. Examples of such reconstruction functions designed for use in touch determination are found in W02009/077962, WO201 1/04951 1 , WO201 1/139213, WO2012/050510, and WO2013/062471 , all of which are incorporated herein by reference.

The operation of the touch sensing apparatus 100 according to one embodiment will now be discussed in reference to Figure 9. Figure 9 is a flow diagram of the method according to some embodiments.

The main controller 618 controls the activation controller 608 to send a signal to at least one light emitter 106a to emit light as shown in step 700.

The main controller 618 controls the touch controller 612 to send a signal to the one or more detectors 106b to detect emitted light from the light emitters 106a as shown in step 702.

The main controller 618 then receives signals from the touch controller 612 based on the detected light at the one or more detectors 106b. The light emitters and detectors 106a, 106b have a region of interest 606 that is sufficiently large that light blocking components 300 mounted at the perimeter 108 of the panel 102 are detectable.

A light blocking component 300 such as a spacer 300 made from a light blocking material will prevent light beams LE emitted from the light emitter 106a reaching the light detector 106b. This is because a portion of the light blocking component 300 is within the region of interest 606. Accordingly the pattern of detection of blocked light can be determined by the main controller 618. The pattern is used for checking the installation of the spacer 300 on the touch sensing apparatus 100. The main controller 618 then determines a distribution of blocked light at least one mountable light blocking component as shown in step 704.

Step 704 can be carried out by the main controller 618 of the touch sensing system 610. However in other embodiments, step 704 is carried out on another processor (not shown) on a separate user terminal (not shown). In some embodiments the user terminal is a computer, a smartphone, tablet or other portable device. The user terminal can be used for quality control and testing the touch sensing apparatus 100. The user terminal can be connectively coupled to the touch sensing apparatus 100 via a wired or wireless connection. The user terminal is configured to receive signals from the main controller 618, the touch controller 612 and / or the activation controller 608. In this way, a user terminal may be a testing apparatus for the touch sensing apparatus 100. In other embodiments the touch sensing apparatus 100 can self-test and self- diagnose and the touch sensing apparatus is a testing apparatus for itself. Although the method can be performed on either the main controller 618, the user terminal, or a combination thereof, the method will be described in reference to the main controller 618 for brevity.

Another embodiment of the method of operation will now be made in reference to Figure 7. The same steps between the method shown in Figure 9 and 7 have the same reference number.

Once the main controller 618 has determined the distribution of blocked light from light blocking components as shown in step 704, the main controller 618 optionally compares the determined distribution of blocked light with a predetermined component light blocking pattern as shown in step 706. The predetermined component light blocking pattern is an expected distribution of detected light blocking components around the perimeter 108 of the panel 102. The predetermined light blocking pattern can be stored in memory 616 of the touch sensing system 610. Alternatively the predetermined light blocking pattern can be stored remotely e.g. on the user terminal. The predetermined component light blocking pattern will depend on the number, size, distribution and orientation of the expected components to be installed. Figure 5 shows an example of a predetermined light blocking pattern because each spacer 300 will be detected in the second region of interest 606.

Optionally, the method comprises generating the predetermined component light blocking pattern as shown in step 708. The main controller 618 can record the light blocking pattern for different required component distributions. The light blocking pattern may differ depending on the model and size of the touch sensing apparatus 100. Step 708 can occur prior to the steps 700, 702, 704, 706.

The main controller 618 then determines a difference between the predetermined component light blocking pattern and the determined distribution of blocked light as shown in step 710. The main controller 618 can determine that a light blocking component 500 is missing from the touch sensing apparatus 100 if additional light LD is detected at the light detectors 106b than compared to the predetermined component light blocking pattern. This is because the light blocking component 500 will block the light beams LE, LD in the second region of interest 606, but is not acutally present during assembly.

Alternatively the main controller 618 can determine that an additional unexpected light blocking component 500 is added to the touch sensing apparatus 100 if reduced light LD is detected at the light detectors 106b than compared to the predetermined component light blocking pattern.

Alternatively the main controller 618 can determine that a light blocking component 500 is misaligned on the touch sensing apparatus 100 if decreased or increased light LD is detected at the light detectors 106b than compared to the predetermined component light blocking pattern. A misaligned component 500 can result in either an increase or a decrease in detected light LD. However, the main controller 618 may calculate the difference between detected light LD from an additional or missing component 500 and a misaligned component 500. This is because there will be a greater difference detectable in the detected light LD when a component 500 is missing or added than if the component 500 is incorrectly orientated.

Optionally, if no difference is detected between the detected distribution of blocked light and the predetermined component light blocking pattern, then the main controller 618 determines that there are no errors in installation as shown in step 712. If no error in assembly of the touch sensing apparatus 100 detected, then in some embodiments no action is taken and step 712 is not carried out. In other words, an absence of an error indicates to the user that all is well with the assembly of the touch sensing apparatus 712. Alternatively, the main controller 618 may generate an“all clear” message to the user. The message can be displayed on the display unit 130 as shown in step 714. Additionally or alternatively the message can be displayed on the user terminal as shown in step 716.

The main controller 618 may determine that there is a difference between the predetermined and detected light blocking patterns in step 710. In this case the main controller 618 may optionally generate component mounting error information as shown in step 718. The component mounting error information can comprise the location of the installation error. The error information can also comprise the type of error such as omission of component, addition of unexpected component, and / or misalignment of component.

The component mounting error information can be sent back to the assembly line as represented by the arrow between step 718 and step 720. For example, if the assembly line comprises automated robotic elements, the robotic assembly line can receive the touch sensing apparatus 100 with the error information and then remount / mount / remove the spacer 300 or other light blocking component. This step is shown in step 720. Step 720 is optional because it may not be possible to fix the installation error of the touch sensing apparatus 100. Instead the component mounting error information is used to assign the touch sensing apparatus 100 for recycling or disposal. In other embodiments the main controller 618 uses the component mounting error information to generate an alert to a user as shown in step 722. The alert is a visual, aural or other indicator to a user that there is an assembly error for a particular touch sensing apparatus 100. The alert may prompt the user to manually inspect the touch sensing apparatus 100 and then remount / mount / remove the spacer 300 or other light blocking component as required as shown in step 720.

The error alert can then be displayed by the main controller 618 on the display unit 130 as shown in 714 and / or on a user terminal as shown in 716.

In some embodiments, the touch sensing apparatus 100 is optionally configured to operate in a first mode using a first region of interest 600 and a second mode using a second region of interest 606. The first region of interest 600 is smaller than the second region of interest 606.

The main controller 618 may receive a signal to indicate that the touch sensing apparatus is being assembled as shown in step 724. The assembly signal is a signal which may be sent to the main controller using a special tool such as the user terminal. If the main controller 618 determines that the assembly signal has been actuated, the main controller 618 operates the touch sensing apparatus 100 in the second mode with the second region of interest 606 as shown in step 726. If no assembly signal is detected by the main controller 618, then the main controller operates the touch sensing apparatus 100 in the first mode with the first field of interest 600 as shown in step 728. For example once the touch sensing leaves the factory, the touch sensing apparatus 100 may operate in the first mode.

However in some embodiments, the touch sensing system 610 always operates in one mode using the second region of interest 606 where light blocking components 300 mountable around the perimeter 108 of the panel 102 are always detectable. In this case the main controller 618 can use signal processing to exclude the detection events due to the light blocking components 300 in the areas 602, 604 of the second region of interest 606. In another embodiment two or more embodiments are combined. Features of one embodiment can be combined with features of other embodiments. Embodiments of the present invention have been discussed with particular reference to the examples illustrated. However it will be appreciated that variations and modifications may be made to the examples described within the scope of the invention.

Claims

1 . A method of operating a touch sensing apparatus, the touch sensing apparatus comprising a panel that defines a touch surface, a plurality of light emitters and detectors arranged along a perimeter of the panel and the light emitters are arranged to emit a respective beam of emitted light above the touch surface, and the light emitters are arranged to receive detection light from the emitted light, the method comprising:

emitting a beam of light from at least one light emitter;

detecting the emitted light at one or more detectors; and

determining a distribution of blocked light by at least one mountable light blocking component on the touch sensing apparatus between the at least one light emitter and the one or more detectors.

2. A method according to claim 1 wherein the at least one light blocking component is at least one spacer mounted between the panel and a housing to limit the movement of the panel with respect to the plurality of light emitters and detectors.

3. A method according to claims 1 or 2 wherein the method comprises comparing the determined distribution of blocked light with a predetermined component light blocking pattern.

4. A method according to claim 3 wherein the method comprises generating a predetermined distribution of blocked light on the basis of a predetermined distribution of light blocking components on the touch sensing apparatus.

5. A method according to claim 4 wherein the method comprises determining a difference between a determining distribution of blocked light and a predetermined component light blocking pattern.

6. A method according to claim 5 wherein the method comprises generating a component mounting error information based on the determined difference.

7. A method according to claim 6 wherein the method comprises generating an alert based on the component mounting error information.

8. A method according to claim 7 wherein the method comprises displaying the alert on a display unit connectively coupled to the touch sensing apparatus.

9. A method according to claims 7 or 8 wherein the method comprises displaying the alert on a terminal connectively coupled to the touch sensing apparatus.

10. A method according to claims 7 to 9 wherein the method comprises mounting additional light blocking components around the perimeter of the panel on the basis of the alert.

1 1 . A method according to any of the preceding claims wherein the method comprises mounting a plurality of light blocking components around the perimeter of the panel.

12. A method according to any of the preceding claims wherein the method comprises

operating in a first mode wherein the steps of emitting a beam of light from at least one light emitter and detecting the emitted light at one or more detectors use a first region of interest and

operating in a second mode wherein the steps of emitting a beam of light from at least one light emitter and detecting the emitted light at one or more detectors use a second region of interest and

the first region of interest is smaller than the second region of interest.

13. A method according to claim 12 wherein the operating of the first mode is a normal mode of operation and the operating of the second mode is a checking mode for assembly of the touch sensing apparatus.

14. A method according to claims 12 or 13 wherein operating the second mode of operation is activated on the basis of an installation signal.

15. A non-transitory computer-readable storage medium storing instructions that, if executed by a processor of a controller, cause the processor to carry out the method of any of claims 1 to 14.

16. A touch sensing apparatus comprising:

a panel that defines a touch surface;

a plurality of light emitters and detectors arranged along a perimeter of the panel and the light emitters are arranged to emit a respective beam of emitted light above the touch surface, and the light emitters are arranged to receive detection light from the emitted light; and

a controller configured to operate in a first mode wherein the plurality of light emitters and detectors use a first region of interest and to operate in a second mode wherein the wherein the plurality of light emitters and detectors use a second region of interest wherein the first region of interest is smaller than the second region of interest;

wherein at least one mountable light blocking component position around the perimeter for the panel is detectable in the second mode and not in the first mode.

17. A testing apparatus for checking component assembly of a touch sensing apparatus, the touch sensing apparatus comprising a panel that defines a touch surface, a plurality of light emitters and detectors arranged along a perimeter of the panel and the light emitters are arranged to emit a respective beam of emitted light above the touch surface, and the light emitters are arranged to receive detection light from the emitted light, and a housing on which the plurality of light emitters and detectors are mountable; the testing apparatus comprising:

an interface for receiving information from the touch sensing apparatus in respect of detection of emitted light at one or more detectors; and

a processor for determining a distribution of where light is blocked by at least one light blocking component between the at least one light emitter and the one or more detectors.