WO2020236071A1

WO2020236071A1 - Touch sensing apparatus

Info

Publication number: WO2020236071A1
Application number: PCT/SE2020/050503
Authority: WO
Inventors: Tomas Svensson; Håkan Bergström; Aleksander KOCOVSKI
Original assignee: Flatfrog Laboratories Ab
Priority date: 2019-05-22
Filing date: 2020-05-15
Publication date: 2020-11-26

Abstract

A touch sensing apparatus comprising a panel that defines a touch surface extending in a plane having a normal axis and a back surface opposite the touch surface, a display arranged proximal to the back surface and configured to display an image through a display portion of the touch surface, a plurality of emitters and detectors arranged along a perimeter of the panel and beneath the panel, a frame component arranged opposite the back surface of the panel, wherein the panel is configured to be shaped by one or more shaping components fixed to the panel and the frame component and configured to exert a force on the panel.

Description

Touch sensing apparatus

Technical Field

The present disclosure relates to touch-sensing apparatus that operates by propagating light by diffusive light scattering above a panel, and in particular to optical and mechanical solutions for defining the light paths and control of curvature of the panel. The present disclosure relates furthermore to a method of assembling a touch sensing apparatus.

Background Art

In one category of touch-sensitive panels known as‘above surface optical touch systems’, a set of optical emitters are arranged around the periphery of a touch surface to emit light that is reflected to travel and propagate 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. I.e. a grid of intersecting light paths is created above the touch surface, also referred to as scanlines. An object that touches the touch surface will attenuate the light on one or more scanlines 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 analyzing the received light at the detectors. Optical and mechanical characteristics of the touch-sensitive apparatus affects the light paths between the emitters/detectors and the touch surface, and accordingly the detected touch signals. For example, variations in the alignment of the opto-mechanical components affects the detection process which may lead to a sub-optimal touch detection performance. Factors such as signal-to-noise ratio, detection accuracy, resolution, the presence of artefacts etc., in the touch detection process may be affected. While prior art systems aim to improve upon these factors, e.g. the detection accuracy, there is often an associated compromise in terms of having to incorporate more complex and expensive opto-mechanical modifications to the touch system. This typically results in a less compact touch system, and a more complicated manufacturing process, being more expensive. To reduce system cost, it may be desirable to minimize the number of electro-optical components. Some prior art systems rely on precise alignment of the various components of the touch sensing apparatus such as the light emitters- and detectors for improved control of the performance. Such systems may however be cumbersome to reliably implement due to the small tolerances with respect to the alignment of the components. Such precise alignment may be difficult to achieve in mass production.

Brief Description of Drawings

These and other aspects, features and advantages will be apparent and elucidated from the following description of examples of the present disclosure, reference being made to the accompanying drawings, in which;

Figure 1a is a schematic illustration, in a top down view, of a touch-sensing apparatus, according to one example of the disclosure;

Figure 1 b is a cross-sectional side view of a touch-sensing apparatus, according to one example of the disclosure;

Figure 2 is a schematic illustration, in a cross-sectional side view, of a touch sensing apparatus, according to one example of the disclosure;

Figure 3 is a schematic illustration, in a cross-sectional side view, of a touch sensing apparatus, according to one example of the disclosure;

Figure 4 is a schematic illustration, in a cross-sectional side view, of a touch sensing apparatus, according to one example of the disclosure;

Figure 5 is a schematic illustration, in a cross-sectional side view, of a touch sensing apparatus, according to one example of the disclosure.

Figure 6 is a schematic illustration, in a cross-sectional side view, of a touch sensing apparatus, according to one example of the disclosure.

Detailed Description

In the following, examples of the present description will be presented for a specific example of a touch-sensitive apparatus. Throughout the description, the same reference numerals are used to identify corresponding elements.

Figure 1a is a top down view of a touch-sensing apparatus 100 comprising a panel 10 that defines a curved touch surface 15. The touch-sensing apparatus 100 comprises a plurality of emitters 50 and detectors 51 arranged along a perimeter of the panel 10.

Figure 1 b is a schematic illustration of a touch-sensing apparatus 100 comprising a panel 10 that defines a touch surface 15 and a back surface 11. The panel 10 is a light transmissive panel in one example. Figure 1 b shows only an emitter 50 for clarity of presentation. The plurality of emitters 50 and detectors 51 (not shown) are fixed to a first frame element 40 extending along the perimeter. The emitters 50 and detectors 51 thus have a substantially fixed position relative the first frame element 40. The emitters 50 and detectors 51 may be mounted to a PCT or substrate 55 which is fixed to the first frame element 40. Substrate 55 may

alternatively be mounted to frame element 30 or other envisaged support

components. The substrate 55 may be fixed to the first frame element 40 or other envisaged support components by screws, pins, clasps, clips, clamps, adhesives, or any other fixation element. The substrate 55 may be arranged in a groove of the first frame element 40, which may provide for a facilitated assembly and an interlocking effect of the substrate 55 into the first frame element 40. The substrate 55 may be mounted essentially in parallel with the plane in which the panel 10 extends.

Arranging the substrate in parallel with the panel 10 provides for minimizing a dimension of the touch sensing apparatus 100 in a direction perpendicular to the plane. A more compact touch sensing apparatus 100 may thus be provided. It should be understood however that the substrate 55 may be arranged with varying angles relative the panel 10 for also maximizing the amount of light reflected towards the touch surface 15. In one embodiment, substrate 55 may be mounted essentially in parallel with a normal axis 104 from panel 10.

The emitters 50 are arranged to emit light 70. The light directing surface 60 is arranged to receive the light from the emitter and direct the light across the touch surface 15 substantially parallel to the touch surface 15. Attenuation of the light e.g. by an object touching the touch surface 15 provides for the detection of the touch position as described above.

The light directing surface 60 may comprises a diffusive light scattering element surface. The diffusive light scattering surface effectively acts as a light source for diffusively emitted light.

As described in PCT patent publication W02018106176, it may be

advantageous to have a panel 10 with a curved touch surface 15. This may be arranged to significantly enhance the amount of light that travels from an emitter to a detector without being deflected away. W02018106176 describes a number of ways of introducing a curvature to the panel 10. Figures 1 b-6 describe some approaches to introducing an amount of torque to the panel 10 that introduces a desirable curvature to the glass.

Figure 1 b describes the use of two components, support component 80 and support component 90. In the example shown in figure 1 b, support component 80 exerts a force on panel 10 at the point of contact between support component 80 and panel 10, in a direction away from frame element 30. Support component 80 and all other components shown in cross section may be provided as components that provide support on the panel or display components at a single point or along a length of the panel or display component, e.g. along a perimeter of the panel or display component. In order to provide an upwards force on panel 10 using support component 80, a first binding surface 85 or a non-binding surface or gasket component may be used. Throughout this disclosure, binding surfaces may comprise adhesive or other fixing method for securing the respective objects to each other, e.g. screws, pins, clasps, clips, clamps, adhesives, etc. Simultaneously, support component 90 exerts a force on panel 10 at the point of contact between support component 90 and panel 10, in a direction towards frame element 30. Here, a means of fixing support component 90 to panel 10 is essential. In order to create the fixed interface between support component 90 and panel 10, second binding surface 95 may be used. The combined effect of the force on panel 10 from support component 80 and support component 90 is to generate a torque on the edge area of the panel 10 to curve the panel 10 upwards towards the edge of the panel 10. In some examples, gasket component 110 is arranged between panel 10 and frame element 30 and is used to limit the effect of the torque on a portion of panel 10 towards the center of the panel 10 by limiting movement of the panel 10. Display component 20 is shown fixed to the panel 10 at back surface 11 to display an image through panel 10. In figure 2, an alternative gasket component arrangement is shown where in the gasket component 110 is provided between display component 20 and frame component 30.

In an example shown in figure 3, support component 120 is provided and arranged to be fixed to frame element 30 via screw 130 and exert a force on panel 10 in a similar manner to support component 80 from figure 1 b. However, support component 120 is configured to present an angled surface 121 to panel 10 such that the portion of panel 10 in contact with support component 120 is induced to match the angle of the angled surface 121 when force is exerted by support component 120 on the panel. The angle of angled surface 121 may be measured from the plane of the touch apparatus, such as plane 1. Therefore, if a particular angle of the panel 10 is required, support component 120 can be used to induce this angle both through the force exerted on panel 10 away from frame element 30 and through the angle of angled surface 121. In order to create a fixed interface between support component

120 and panel 10, third binding surface 125 may be used.

Figure 4 shows an example similar to figure 3 in which support component 140 is also employed. Similar to support component 120, support component 140 may be arranged to be fixed to frame element 30 and exert a force on panel 10. support component 140 may configured to present an angled surface 141 to panel 10 such that the portion of panel 10 in contact with support component 140 is induced to match the angle of the angled surface 141 when force is exerted by support component 120 on the panel 10. The angle of angled surface 121 may be measured from the plane 1 of the touch apparatus. In this way, if a particular curvature of the panel across a length of the panel 10, support component 120 and support component 140 can be used in combination to induce this curvature through the respective force exerted on panel 10 and through the angle of angled surface 121 and angled surface 141. In one example, the angle of angled surface 121 and the angle of angled surface 141 is different. In one example, the angle of angled surface

121 from the plane 1 of the touch apparatus is larger than the angle of angled surface 141 from the plane 1. In this way, the panel 10 can be increasingly curved upwards towards the edges of the panel 10.

As with support component 120, fourth binding surface 145 may be used to provide a fixed interface between support component 140 and panel 10.

It is noted that curvature and other dimensions shown in the figures may be shown in an exaggerated manner to enable easy comprehension of the concepts described.

With respect to the discussion above, "diffuse reflection" refers to reflection of light from a surface such that an incident ray is reflected at many angles rather than at just one angle as in "specular reflection". Thus, a diffusively reflecting element will, when illuminated, emit light by reflection over a large solid angle at each location on the element. The diffuse reflection is also known as "scattering".

It is acknowledged that a difference exists between the optical effect resulting from a‘true diffusor’ surface and a‘rough specular surface’ e.g. a sandblasted surface. However, the two are treated as functionally equivalent for the purposes of this description.

Figure 5 shows an example in which support component 150 is also provided and arranged to be fixed to frame element 30 via a screw or other fixing means. In this example, display component 20 is provided with a display backplate 21. In the example of an OLED display, display backplate 21 may comprise a sheet of hard material to protect the fragile OLED layers, e.g. metal or hard plastic. Support component 150 is arranged to exert a force on display backplate 21 at the point of contact between support component 150 and display backplate 21 , in a direction away from frame element 30. In order to create a fixed interface between support component 150 and display backplate 21 , fifth binding surface 155 may be used.

Support component 150 may also be configured to present an angled surface 151 to display backplate 21 such that the portion of display backplate 21 in contact with support component 120 is induced to match the angle of the angled surface 151 when force is exerted by support component 120 on the panel. The angle of angled surface 151 may be measured from the plane of the touch apparatus, such as plane 1 .

Figure 5 also shows a display backplate tension arrangement between the display backplate 21 and frame element 30 comprising fixing component 132 and screw 131. In this example, fixing component 132 is fixed to display backplate 21. Fixing component 132 is also connected to screw 131. Screw 131 may be rotated to exert a force on fixing component 132, and therefore display backplate 21 , towards back plate 30. In combination with support component 150 exerting a force on display backplate 21 in the opposite direction, the shape/warp of panel 10, display component 20, and display backplate 21 can be controlled. In this way, the panel 10 can be curved upwards towards the edges of the panel 10 and downwards towards the frame element 30 in a more central region of the panel 10. Alternative methods for the display backplate tension arrangement adjustably applying a force to display backplate 21 towards back plate 30 may be envisaged. In some examples, the display backplate tension arrangement is fixed, not adjustable, and may be arranged to be secured between display backplate 21 and back plate 30 during manufacture. Examples of non-adjustable arrangements may include screws, pins, clasps, clips, clamps, adhesives, etc. In one example, the display backplate tension arrangement may be arranged to exert a force on the display backplate 21 at a position of greater than 10cm from the edges of the panel 10. In one example, the display backplate tension arrangement may be arranged to exert a force on the display backplate 21 at a position within 10cm from a center point of the panel 10.

In one example, adhesive layers are arranged between display backplate 21 , display component 20 and/or between display component 20 and panel 10. These adhesive layers allow the force exerted on display backplate 21 by the display backplate tension arrangement to be transferred all the way to the panel 10 to ensure the curvature of the panel 10 can also be controlled by the display backplate tension arrangement.

In an example of a feature shown in figure 5, panel 10 is larger than the display component 20 and reaches all the way to frame element 40. This provides an effective seal that prevents ambient dust and debris from reaching substrate 55. In one example, panel 10 also comprises infrared transmissive film 190 on a surface proximal to substrate 55. Infrared transmissive film 190 may be arranged to substantially block visible light from reaching substrate 55 and to prevent substrate 55 from being visible from the touch surface 15. Infrared transmissive film 190 may be arranged to cover an area from the edge of panel 10 or from frame element 40, to either an edge of display component 20 or to an edge of a support component 120.

Figure 6 shows an example in which support component 180 is also provided and support component 180 and support component 80 are arranged either side of substrate 55. In this example, support component 180 contacts the panel 10 at a position proximal to the edge of panel 10. Where the edge of panel 10 is positioned close or in contact with frame element 40, the space beneath panel 10 may be sealed off from dust or debris from the touch surface 15. In one example, support component 180 is arranged such that a surface of support component 180 contacting panel 10 is further from back plate 30 in a direction of axis 104 than a surface of support component 80 that is in contact with panel 10. The differences of height between support component 80 and support component 180 induces a shaping of panel 10. As with support component 80 having first binding surface 85, support component 180 may comprise sixth binding surface 185. In one example, support component 80 and support component 180 are integrated with frame element 40, and either formed from a single component with frame element 40 or fixable connected to frame element 40. In the example of figure 6, substrate 55 is shown to be orientated in an optional vertical orientation. As is readily appreciated by a person skilled in the art, other examples than the ones disclosed above are equally possible within the scope and spirit of the disclosure, which is defined and limited only by the appended patent claims.

For example, the specific arrangement of emitters 50 and detectors 51 as illustrated and discussed in the foregoing is merely given as an example. The inventive coupling structure is useful in any touch-sensing system that operates by transmitting light, generated by a number of emitters 50, across a panel 10 and detecting, at a number of detectors 51 , a change in the received light caused by an interaction with the transmitted light at the point of touch.

Claims

1. A touch sensing apparatus (100) comprising

a panel (10) that defines a touch surface (15) extending in a plane (1 ) having a normal axis (104) and a back surface (11 ) opposite the touch surface (15),

a display component (20) arranged proximal to the back surface (11 ) and configured to display an image through a display portion of the touch surface (15), a plurality of emitters (50) and detectors (51 ) arranged along a perimeter of the panel (10) and beneath the panel (10),

a frame component (30) arranged opposite the back surface (11 ) of the panel

(10),

wherein the panel (10) is configured to be shaped by one or more shaping components fixed to the panel (10) and the frame component (30) and configured to exert a force on the panel (10).

2. The touch sensing apparatus (100) of claim 1 further comprising a first shaping component configured to exert a force on the panel (10) in a direction away from the frame component (30).

3. The touch sensing apparatus (100) of claims 1 or 2 further comprising a second shaping component configured to exert a force on the panel (10) in a direction towards from the frame component (30).

4. The touch sensing apparatus (100) of claim 3 wherein the first shaping component is arranged closer to the perimeter of the panel (10) than the second shaping component.

5. The touch sensing apparatus (100) of claim 4 wherein an emitters (50) or detectors (51 ) is position between the first shaping component and the second shaping component.

6. The touch sensing apparatus (100) of claims 2-5 comprising a third shaping component configured to limit a curvature of the panel (10) in a direction towards from the frame component (30).

7. The touch sensing apparatus (100) of claim 6 wherein the third shaping component is arranged further from the perimeter of the panel (10) than the first and/or second shaping component.

8. The touch sensing apparatus (100) of any preceding claim, wherein display component (20) comprises a display backplate (21 ), and wherein at least one shaping component being configured to exert a force on the display backplate (21 ).

9. The touch sensing apparatus (100) of claim 8, wherein at least one shaping component being configured to exert a force on the display backplate (21 )in a direction towards from the frame component (30).

10. The touch sensing apparatus (100) of claim 9, wherein the at least one shaping component configured to exert a force on the display backplate (21 )in a direction towards from the frame component (30) comprises an adjustable tension

arrangement.

11. The touch sensing apparatus (100) of claim 10, wherein the adjustable tension arrangement comprises an adjustable screw.

12. The touch sensing apparatus (100) of any of claims 8-10, wherein at least one shaping component being configured to exert a force on the display backplate (21 )in a direction away from the frame component (30).

13. The touch sensing apparatus (100) of any preceding claim, wherein at least one shaping component being configured to exert a force by means of an angled surface.