Patent Application
20250138691
The disclosure generally relates to the field of element arrangements and associated methods of manufacture, including those for resistive, inductive, mechanical and capacitive touch sensors. In particular, although not exclusively, the disclosure relates to a touch sensor arrangement for increasing the practical size range and/or resolution of touch screens, keypad arrays and LED or electro-luminescent arrays or displays, memory devices, electro-mechanical actuators plus many other unspecified technologies.
A major problem that limits the size of multi-touch, projected capacitance, resistive, and inductive touch-screens is the electrical resistance of the sensing elements in the screen.
Most touchscreens use a transparent array of horizontal (x), and vertical (y) sensing tracks that extend from one side of the screen to the opposite side.
In order to attain high resolution between multiple independent fingers, the elements are divided up into many thin conductive traces less than 1 cm wide, the vertical and horizontal elements crossing each other at 90 degrees, but without any electrical contact.
These intersections are where touch sensing occurs when using “mutual capacitance” sensing, whereas it is the tracks themselves that sense when using “self-capacitance”. “Self-capacitance” may be used for determining the unambiguous position of just one finger, the finger position being determined by the horizontal and vertical conductive elements that show a maximum change when the finger approaches. It may also be used for the detection of multiple fingers, but usually, though not always, with some degree of ambiguity. “Mutual capacitance” may be used to determine the unambiguous position of one or more fingers. In mutual capacitive methods, known techniques are employed that only enable intersections between sensing and controlling elements to detect a finger approaching that intersection. These intersections are called nodes. The remainder of these elements is insensitive to the approaching finger. The finger positions may be determined by finding intersections of the horizontal (x) and vertical (y) conductive elements that show a significant change in signal transmission between these elements (for example, from horizontal controllable to vertical sensing elements) when a finger approaches that intersection thereby causing a change in the capacitive coupling between these elements.
In the example illustrated in
Table 2 provides a truth table showing the arrangement of sensing node for the touch sensor 200 of
Many different types of material can be used for making this x/y matrix of sensing elements. For example, Indium Tin Oxide (ITO) has been used traditionally, and has a resistance of about 50 ohms per square, restricting its use to relatively small applications. Metal mesh is commonly used for much larger touchscreens due to its greater physical flexibility and lower resistance of about 15 ohms per square. Whatever the material used, however, all touchscreens could be made much larger if the resistance of the sensing elements could be reduced.
The structures disclosed herein may be provided for a number of different types of applications, including conductive structures, for example:
The structures disclosed herein may also be provided for a number of different types of non-conductive applications, such as fibre-optic, acoustic, hydraulic.
Although the specific examples described often relate to touch sensors, it will be appreciated that the same geometric arrangements can also be used in these other contexts. In the case of non-conductive applications, the conductors described with reference to touch sensors may be replaced with the corresponding non-conductive elements, such as a fibre-optic cable, acoustic line or hydraulic element.
According to a first aspect, there is provided a touch sensor comprising:
One or more of the conductive elements may split into a plurality of sensing elements at the at least one edge region to provide the pairs of conductive elements. One or more of the plurality of conductive elements may have a sensing element in the sensing region and a connection portion in the at least one edge region. The sensing elements may comprise wire. The connection portion may comprise trace conductor on a printed circuit board.
Each conductive element of the first set of conductive elements may be electrically connected to a corresponding conductive element of the second set of conductive elements at the at least one edge region to provide respective connected pairs of conductive elements. The conductive elements may be sensing elements. Each pair of conductive elements may cross any element of a different pair of conductive elements no more than once. For example, the elements may not cross each other more than once if this would create ambiguity, which may be referred to an undesirable ambiguity.
One conductive element of a pair of conductive elements may not cross another conductive element of that same pair of conductive elements. One conductive element of a pair of conductive elements may not cross the same conductive elements as the other conductive element of that pair of conductive elements.
Each conductive element of the first set of conductive elements may be electrically connected to a corresponding conductive element of the second set of conductive elements via the at least one edge region to provide respective connected pairs of conductive elements. Each pair of conductive elements may be coupled to touch sensor circuitry via the at least one edge region.
In one or more examples, there are no electrical connections between respective pairs of conductive elements.
A plurality of nodes may be formed at points where conductive elements of the plurality of conductive elements cross one another. A set of conductive elements may comprise multiple conductive elements.
In one or more examples, each conductive element of the first set of conductive elements does not form, with the corresponding conductive element of the second set of conductive elements, a node within the sensing area. Each conductive element of the first set of conductive elements may not be electrically connected, with the corresponding conductive element of the second set of conductive elements, within the sensing area.
In one or more examples, one or more of the first set of conductive elements extends in the sensing region in a direction that is transverse to a direction in which one or more of the second set of conductive elements extends. One conductive element of a pair of conductive elements may not extend parallel with another conductive element of that pair of conductive elements.
The sensing region may be formed by a substrate comprising a first portion that has been joined to a second portion.
In one or more examples, one or more of the plurality of conductive elements have a sensing portion in the sensing region and a connection portion in the at least one edge region. The sensing portion of the one or more of the plurality of conductive elements comprise wire. The sensing portion may be made from a different material or have a different thickness than the connection portion. The sensing portion may be joined to the connection portion or the two portions may be integrally formed. The sensing portion may extends within the sensing region. The connection portion may be connected to the sensing portion. The connection portion may extend within the first edge region. The connection portion may be connected to an electrical connector. The connection portion of the one or more of the plurality of conductive elements may comprise trace conductor on a printed circuit board.
In one or more examples, the at least one edge region comprises a first edge region. The first and second set of conductive elements may be configured to be connected to circuitry only at or via the first edge region.
In one or more examples, the first and second sets of conductive elements form a matrix of nodes within the sensing region.
In one or more examples, the at least one edge region forms a periphery around the bounds of the matrix of nodes.
In one or more examples, pairs of conductive elements form respective loops.
In one or more examples, ends of conductive elements are joined to form a substantially three-dimensional conductive array.
The sensing region may be bounded by the first edge region and a second edge region, wherein the second edge region opposes the first edge region, wherein the sensing region of the sensing area is bounded by a third edge region that extends between the first edge region and the second edge region, wherein the sensing region is bounded by a fourth edge region that extends between the first edge region and the second edge region and opposes the third edge region. The third edge region may be joined to the fourth edge region such that the sensing region is provided on a three dimensional substrate.
Ends of conductive elements may be joined to form a three dimensional conductive array. The sensing region may be provided on a three dimensional substrate.
In one or more examples, ends of conductive elements are joined to form a substantially cylindrical conductive array.
In one or more examples, one or more of the conductive elements may each split into a plurality of sensing elements at the at least one edge region. The respective sensing elements of a particular conductive element may extend in opposing directions from the at least one edge region, through the sensing region, and may not cross one another within the sensing region.
For a plurality of conductive elements that each split into two sensing elements at the at least one edge region, a sensing element from a first conductive element may cross a sensing element from a second conductive element to form a node within the sensing area. A sensing element from the first conductive element may cross a sensing element from a second conductive element in a transverse direction, such as at an angle from 10 degrees to 90 degrees, such as 20 degrees, 40 degrees or 80 degrees. The sensing element from the first conductive element and the sensing element from the second conductive element may extend from a node in transverse directions. Pairs of sensing elements may extend in opposing, transverse or perpendicular directions.
A plurality of sensing elements that split from a particular conductive element may be coupled to an electrical connector located at the same at least one edge region. The electrical connector may be configured to provide electrical connections to one or more further sensing elements.
Sensing elements split from the one or more conductive elements may form an array of elements in the sensing region with one or more conductive elements that do not split. The array of elements in the sensing region may alternate between sensing elements split from the one or more conductive elements and the one or more conductive elements that do not split. The one or more conductive elements that do not split may be coupled to a further electrical connector located at the same at least one edge region, or a plurality of such further electrical connectors.
The sensing region may be bounded by a first edge region and a second edge region that opposes the first edge region. The plurality of conductive elements may extend within, or through, the sensing region from the first edge region. The sensing region of the sensing area may be bounded by a third edge region that extends between the first edge region and the second edge region. The sensing region may be bounded by a fourth edge region that extends between the first edge region and the second edge region and opposes the third edge region. The edge regions may form a periphery around the bounds of the matrix of cross over points.
One or more of the first and second sets of conductive elements may be sensing conductive elements, or may be controlling conductive elements at some times, and sensing conductive elements at other times. The first and second set of conductive elements may be connected to circuitry only at the first edge region.
Each conductive element (or pair of conductive elements) may cross over another conductive element (or pair of conductive elements) within the sensing region, at one unique sensing/controlling node, only once at most, for example if this would causes unwanted or unresolvable ambiguity.
The conductive elements comprise one or more of: an insulation coated metallic wire or a conductive track. The sensor may comprise circuitry connected to the conductive elements. The circuitry may be configured to determine one or more touch positions in the sensing area.
The wire may be enamel coated copper. The wire may be tungsten. The wire may have a diameter range from 5 microns to 50 microns. The wire may have a diameter range from 3 microns to 17 microns.
There may be provided a “no soldering” capacitive method for terminating enamel coated wires, whereby the wires are first plotted on adhesive coated plastic or paper, in a very tight pattern at the termination point, this pattern then being overprinted with conductive ink, using a stencil, screen printing, or ink-jet printing, a connector terminal then being placed over, and in direct electrical contact with the conductive ink, there being no direct electrical contact between the wire and the connector terminal.
There may be provided a “no soldering” method for terminating bare wires, whereby the wires are first plotted on adhesive coated plastic or paper, in a tight pattern at the termination point, this pattern then being overprinted with conductive ink, using a stencil, screen printing, or ink-jet printing, a connector terminal then being placed over, and in direct electrical contact with the conductive ink.
Terminating wires may be laid down on adhesive coated film. A printed circuit board (pcb) terminal strip may be placed on the adhesive film before the wire is plotted. The pcb may have conductors facing upward, in such a position whereby, as the wire(s) are plotted they run over the pcb in the places where the conductive traces are found. After the plotting is completed, the wires may be directly soldered to the conductive traces.
A pcb terminal strip may be placed on the adhesive film after the wire is plotted, the pcb having conductors facing downward, in such a position whereby, the plotted wire(s) run under the pcb in the places where the conductive traces are found. The wires may be soldered through the film to the conductive traces.
The touch sensor may comprise a plurality of processors coupled to the plurality of conductive elements. The plurality of processors may be configured to operate either synchronously or asynchronously with each other. The plurality of processors may operate independent of each other.
Alternatively, the touch sensor may comprise a only a single processors coupled to the plurality of conductive elements.
According to a further aspect there is provided a touch screen comprising:
In one or more examples, the display area comprises an array of picture elements having columns and rows of picture elements. The first set of conductive elements of the touch screen may extend obliquely to a row or column of picture elements.
Also disclosed is a touch sensor comprising:
According to a further aspect, there is provided a method of forming a conductor arrangement, comprising:
In one or more examples, the method comprises modifying the arrangement of the plurality of conductive elements adjacent to a join of the portions of the substrate to merge the respective sets of conductive elements.
In one or more examples, the plurality of conductive elements comprise wires.
In one or more examples, the conductor element arrangement may be a touch sensor.
According to a further aspect, there is provided a method of forming a conductor arrangement, comprising:
Joining the third edge region to the fourth edge region may form the substrate into a cylindrical tube.
According to a further aspect, there is provided a touch sensor comprising:
The plurality of conductive elements may comprise a first set of conductive elements and a second set of conductive elements. Each conductive element of the first set of conductive elements may be electrically connected to a corresponding conductive element of the second set of conductive elements at a first edge region to provide respective connected pairs of conductive elements. Each pair of conductive elements may be configured to be coupled to touch sensor circuitry via the at least one edge region.
According to a further aspect, there is provided an element arrangement comprising:
The element arrangement may be a conductive element arrangement and the elements are conductive elements, in which each pair of elements is configured to be coupled to circuitry via the at least one edge region. The element arrangement is a display matrix.
According to a further aspect there is provided a conductor arrangement comprising:
In general, the conductor arrangement may comprise any of the features described with reference to a touch sensor embodiment, as well as display embodiments, for example.
Each pair of conductive elements may cross any element of a different pair of conductive elements no more than once. For example, the elements may not cross each other more than once if this would create ambiguity, which may be referred to an undesirable ambiguity. In some situations, ambiguity may not be a problem. For example, with a cylindrical display, perhaps two identical images always need to be shown on either side of the cylindrical display.
Instead of electrical conductors, the electrical part can be omitted, leaving just conductors. These conductors could conduct electricity, water, air, light, sound waves etc. These could be electrically conductive, optical fibres, hydraulic hoses, acoustic/ultrasonic fibres, etc. A typical actuator might be a piezo-electric pad used for haptic sensing.
Also disclosed is a sensor matrix and/or actuator matrix and/or display matrix comprising:
Various aspects of the disclosure are described by way of example and with reference to the accompanying drawings in which:
The present disclosure is primarily, though not exclusively directed to touch screen arrangements with reduced sensing element resistance, and associated methods of manufacture. One way to reduce the resistance, without degrading the clarity of the touchscreen, is to reduce the lengths of the sensing element.
As described in WO 2017/013437 A1 (Binstead) has shown that touchscreen elements can be wired diagonally, usually, though not always with each sensing element intersecting crossing every other sensing element at 90 degrees, without any direct electrical contact. The entire content of WO 2017/013437 A1, which also relates to US 2018/0217696 A1, is incorporated herein by reference.
Such structures may be formed using the method and apparatus for forming a wire structure disclosed in GB 2541336 A (Binstead), the entire content of which is also incorporated herein by reference. In such examples, fine, insulation coated wire may be plotted onto an adhesive coated clear polyester film, the resulting plot being encapsulated in a top clear polyester film. Plot a diagonal arrangement may be achieved by providing suitable software instructions. Other methods of manufacture using transparent conductive coatings are also available.
The touch sensor 300 may be a capacitive touch sensor, such as a projected capacitance touch sensor. The touch sensor 300 may comprise circuitry (not shown) connected to the conductive elements 301-308 and configured to determine one or more touch positions in the sensing area based on signals from the conductive elements 301-308. The circuitry may operate using either mutually capacitive or self-capacitive principles, or both alternately, such that the touch sensor 300 is a mutual capacitive touch sensor and/or a self-capacitive touch sensor. For example, in mutual capacitance mode, one conductive element 301 may be a controllable conductive element and the remaining conductive elements, 302, 303, 304, 305, 306, 307, 308, may be a set of sensing conductive elements. Alternatively, in self capacitance mode, all of the conducting elements 301-308 may be sensing elements. The circuitry may also be configured to use the conducting elements 301-308 as shielding elements or masking elements, as is known in the art. The conductive elements 301-308 may be formed using a metallic wire or a conductive track.
The sensing area 309 comprises a first set of conductive elements 301, 303, 305, 307 and a second set of conductive elements 302, 304, 306, 308. Each set of conductive elements comprises a plurality of conductive elements 301-308 in this example but more or less elements may be used. If elements intersect at 90 degrees then the sensing area 309 is rectangular, as in this example.
A central region 310 of the sensing area 309 is bounded by first, second, third and fourth edge regions 312-318. That is, the edge regions extend along the sides of the sensing area 309. The central region 310 of the sensing area 309 may also be referred to as a sensing region because it is the region of the sensing area that is primarily responsible for performing sensing. The edge regions 312-318 have a width, in this example, and are shown as regions with point shading in
In the touch sensor 300 of
The conductive elements 301, 303, 305, 307 of the first set each extend through the central region 310 from the first edge region 312 to the second edge region 314 via the third edge region 316. In this example, the conductive elements 301, 303, 305, 307 of the first set each have a first portion 301a, 303a, 305a, 307a that extends in a first direction 320 between the first edge region 312 and the third edge region 316. The first portions 301a, 303a, 305a, 307a may extend through the central region 310. The conductive elements 301, 303, 305, 307 of the first set each change direction within the third edge region 316. Before the change in direction, the conductive elements 301, 303, 305, 307 of the first set are getting closer to, or approaching, the third edge region 316 and after the change in direction the conductive elements 301, 303, 305, 307 of the first set are getting further away from the third edge region 316. After the change in direction, the conductive elements 301, 303, 305, 307 of the first set each have a second portion 301b, 303b, 305b, 307b that extends in a second direction 322 between the third edge region 316 and the second edge region 314. The second portions 301b, 303b, 305b, 307b may extend through the central region 310. The first set of conductive elements 301, 303, 305, 307 passes through the third edge region only once. In this example, the first and second portions of the first and second sets of elements are straight and parallel to other corresponding portions within the same set of elements.
The second set of conductive elements 302, 304, 306, 308 comprises different conductive elements to the first set of conductive elements 301, 303, 305, 307. The second set of conductive elements 302, 304, 306, 308 is interdigitated with the first set of conductive elements 301, 303, 305, 307 at the first edge region 312. In this way, each of the first set of conductive elements 301, 303, 305, 307 has one or two of the second set of conductive elements as its nearest neighbours.
The conductive elements 302, 304, 306, 308 of the second set each extend through the central region 310 from the first edge region 312 to the second edge region 314 via the fourth edge region 318. In this example, the conductive elements 302, 304, 306, 308 of the second set each have a first portion 302a, 304a, 306a, 308a that extends in the second direction 322 between the first edge region 312 and the fourth edge region 318. The first portions 302a, 304a, 306a, 308a may extend through the central region 310. The conductive elements 302, 304, 306, 308 of the second set each change direction within the fourth edge region 318. Before the change in direction, the conductive elements 302, 304, 306, 308 of the second set are getting closer to, or approaching, the fourth edge region 318 and after the change in direction the conductive elements 302, 304, 306, 308 of the second set are getting further away from the fourth edge region 318. After the change in direction, the conductive elements 302, 304, 306, 308 of the second set each have a second portion 302b, 304b, 306b, 308b that extends in the first direction 320 between the fourth edge region 318 and the second edge region 314. The second portions 302b, 304b, 306b, 308b may extend through the central region 310. The second set of conductive elements 302, 304, 306, 308 passes through the fourth edge region only once.
Each of the first and second portions 301a-308a, 301b-308b of the first and second sets of conductive elements 301-308 is diagonal with respect to the first edge direction 323 in which the first or second edge regions 312, 314 extend, and diagonal with respect to a third edge direction 324 in which the third and fourth edge regions 316, 318 extend. In this example, the first portions 301a, 303a, 305a, 307a of the first set of conductive elements 301, 303, 305, 307 extend transverse or obliquely to the first portions of the second set of conductive elements 302, 304, 306, 308. Similarly, the second portions 301b, 303b, 305b, 307b of the first set of conductive elements 301, 303, 305, 307 extend transverse or obliquely to the second portions 302b, 304b, 306b, 308b of the second set of conductive elements 302, 304, 306, 308. The arrangement of the first and second sets of conductive elements 301-308 results in the formation of a matrix of cross over points, which may also be referred to as intersections or nodes of the touch sensor 300. The respective conducting elements 301-308 remain separate, or isolated, from each other at the various nodes. The arrangement of the first and second sets of conductive elements 301-308 is such each conductive element crosses over each of the other conductive elements only once.
The sensing area may be considered to be defined by the bounds of the conductive elements 301-308 of the touch sensor 300. The central portion 310 of the sensing area may be considered to be defined by the bounds of the nodes of the touch sensor 300. That is, the matrix of cross over points may define the central region 310 of the sensing area and the edge regions 312, 314, 316, 318 of the sensing area may form a periphery around the bounds of the matrix of cross over points.
One conductive element, in this example a fourth conductive element 304, is emphasized for clarity, but essentially follows the same rules as, and has a similar layout to, all the other elements. The fourth conductive element 304 runs up the touch sensor 300 diagonally to the left, first crossing its nearest neighbour to the left, a third conductive element 303 at a third-fourth node 326. When the fourth conductive element 304 gets to the left side of the sensing area 309 at the fourth edge region 318, it turns right, and traces a route diagonally up the sensing area 309, eventually crossing its original nearest neighbour to its right, a fifth conductive element 305 at a fourth-fifth node 328, before finishing at the top of the sensing area 309 at the second edge region 314. Throughout this route, the fourth conductive element 304 crosses all of the other elements 301-303, 305-308 just once. The other elements 301-303, 305-308 follow similar routes to the fourth conductive element 304.
With an even number of elements, half of the elements 301-308 start off extending to the right and the other half start off extending to the left. This layout advantageously results in all the elements 301-308 being very similar to each other, in terms of their layout and length, resulting in similar sensitivity to touch.
The presence of a finger adjacent to a node of the touch sensor 300 may be detected by comparing signals from the various conductive elements 301-308. The touch sensor 300 may itself comprise, or be attached to, circuitry that is connected to the conductive elements 301-308 and configured to determine one or more touch positions in the sensing area 309. Such circuitry, which may implement a mutual capacitance or self-capacitance sensing technique, is discussed further in US2018/0217696, incorporated by reference.
The conductive elements 301-308 of the touch sensor 300 each have two ends: a first end at the first edge region 312 and a second end at the second edge region 314. The conductive elements 301-308 are each configured to be connected to the circuitry at only the first end in this example. The second end of the conductive elements 301-308 does not require termination in this example. Because all the elements 301-308 are connected to a terminal at one end only with no terminal connections on the other three sides, very little “non-sensing” zone 311 is created around the second, third and fourth edge regions 314, 316, 318. This means that a bezel may not be required to hide “feed” wires along the edges of the touch-screen.
The non-sensing zone 311 is the region around the sensing area that comprises “feed” tracks from a connector to the start of the conductive elements within the sensing area. In this case, the touch sensor 300 does not have a non-sensing zone along three of its sides, but does have a non-sensing zone 311 where tracks are led to the connector at the bottom.
If an edge region has a sensing element in it, such as a returning “bent” sensing element, and is being used with self-capacitance, then this is a zone that is capable of detecting a finger, even though this may be outside the display zone. However, if a region has no intersecting elements in it, and is being used solely with “mutual capacitance, then this is, in effect, a non-sensing zone, which may also be considered to be an edge region of the sensing area. In
In this example, there are seven conductive sensing elements to allow comparison with the conventional arrangements described previously with reference to
All the conductive sensing elements 401-407 have the same length of 1.414 times the minimum dimension of the touchscreen. This diagonal layout nearly doubles the number of intersections possible for a fixed number of sensing elements but, creates a 1:1 aspect ratio touchscreen that increases the length, and therefore the resistance of the conducting elements from 1 unit of length, for a square x/y touchscreen, to 1.414 units of length for a square diagonally wired touchscreen, increasing the resistance by 41.4%.
Any of the examples of touch sensors with diagonally extending sensing elements, the sensing region of the touch sensor may be aligned with edges of a display area. In particular, an orientation of the central sensing region may be aligned with respect to edges of the display area. The conductive elements are therefore arranged obliquely to the edges of the display area in such examples.
The display area typically comprises an array of picture elements (pixels) arranged in columns and rows. The first and second sets of conductive elements of the touch screen extend obliquely to the rows and columns of pixels. The conductive elements of the touch sensor also extend diagonally to edges of the display area.
With the elements disposed at 45 degrees to the edges of the display area, the sensing area would normally be square.
With a rectangular display, the touch sensor of
The sensing area of
It has been found that the unused nodes that were in the material that is cut off can be usefully re-positioned to alter the aspect ratio of the sensing area. For example, the top half of the diagonal touchscreen can be “moved” to the side of the bottom half of the touchscreen, and, by re-arranging the routes of some of the edge elements, it can merge “seamlessly” with the bottom half. This changes the aspect ratio from 1:1 to 1:4 (0.5:(1+1)) potentially, without losing any of the sensing nodes. Conductive elements from the “moved” top half can be electrically “re-joined” to the appropriate conductive elements of the “unmoved” bottom half by low resistance conductive tracks, in the “non touch” zone, at the bottom of the touchscreen. This arrangement significantly reduces the length, and therefore the resistance of the conductive elements in the touch sensing area. Instead of the conductors, in a diagonally wired 1:1 aspect ratio touchscreen being 41% longer than the conductors in an equivalent x/y touchscreen, when converted to 1:4 aspect ratio, by the above transformation, the diagonal conductors become 82% shorter than the longest x/y conductor (0.7 vs 4).
The disclosure therefore provides a method of forming a conductor arrangement, comprising the equivalent of:
The plurality of conductive sensing elements comprises a first set of conductive sensing elements 701a-707a and a second set of conductive sensing elements 701b-707b. Each conductive sensing element of the first set of conducting sensing elements 701a-707a is configured to be electrically connected to a corresponding conducting element of the second set of conducting sensing elements 701b-707b at the first edge region 712. In this example, there is a direct electrical connection between such sensing elements within the first edge region 712. The direct electrical connection means that they are in galvanic contact. The corresponding conductive sensing elements of the first and second set of conducting sensing elements provide respective connected pairs of the plurality of conductive sensing elements. Each pair of conductive sensing elements is configured to be coupled to touch sensor circuitry by the at least one edge region. In the example illustrated in
The first conductive sensing element 701a of the first set of conductive sensing elements extends within the sensing region 720 in a direction that is transverse to a direction in which the first conductive sensing element 701b of the second set of conductive sensing elements extends. The first and second sets of conductive sensing elements also comprise conductive sensing elements (the fifth conductive sensing element 705b of the second set of conductive sensing elements and the second conductive sensing element 702b of the second set of conductive sensing elements) adjacent to the third and fourth edge regions 716, 718 which change direction at the edge regions. Such conductive sensing elements comprise a portion that extends in a direction that is transverse to a direction in which conductive elements in the other set extend and a portion that extend in the same direction as the corresponding conductive element in the other set extends.
There is no electrical connection (no galvanic conduction) between the different respective pairs of conductive sensing elements. For example, the first conductive sensing element 701a, 701b of the first and second sets of conductive sensing elements are not electrically connected to the third conductive sensing elements 703a, 703b of the first and second sets of conductive sensing elements. However, as shown in the illustrated example, the first conductive sensing element 701b of the second set of the conductive sensing elements crosses other sensing elements, including the third sensing element 703a of the first set of conductive sensing elements at a node. There is no direct electrical connection at the node, or elsewhere within the sensing region or edge regions between the different pairs of conductive sensing elements.
Providing an arrangement in which each pair of conductive sensing elements crosses any other element of the plurality of conductive elements no more than once provides a touch sensor arrangement avoiding ambiguity between detected signals and touch positions.
That is, if there is only one position associated with a crossing between the first pair of conductive sensing elements and the third pair of conductive sensing elements then the detection of a signal associated with a touch event adjacent to a node formed by the first and third pairs of conductive sensing elements results in a signal that can be unambiguously associated with a single touch position.
In most touch sensing situations, where a conductive element “a” crosses a second conductive element “b”, it is impossible to distinguish the difference, without ambiguity, between: a) a” being the controlling element while “b” is the sensing element, and b) “b” being the controlling element while “a” is the sensing element. In such a situation, pairs of conductive elements may not cross each other more than once inside the touch sensing zone.
Where it is possible to distinguish between situation a) and b) described above, then it is possible for the pairs of conductive elements to cross each other more than once.
Table 3 provides a truth table showing the arrangement of sensing node for the touch sensor 700 of
Joining the top half of the screen to the side of the bottom half, halves the length of all of the tracks, but with the consequence that it changes the aspect ratio from 1:1 to 0.5:2 (or 1:4).
The tracks, in the original 1:1 touchscreen were all equal in length to the diagonal of the touchscreen: square root 2 or 1.414 units. In the new touchscreen this has been halved to 0.707 units.
An x/y touchscreen, with an aspect ratio of 1:4 has a maximum conductor length of 4 units. Therefore, the sensing element length in a 1:4 aspect ratio diagonally wired touchscreen is only (1.414)/4 or 35% as long as the horizontal sensing element in a 1:4 aspect ratio x/y wired touchscreen. However, it is (1.414)/1 or 41% longer than the vertical element.
Since the maximum sensing route, for a particular signal is the sum of one horizontal and one vertical element, in an x/y layout, and the sum of two diagonal elements in a diagonal layout, the maximum sensing route in a 1:4 aspect ratio is: 5 for x/y and 2.828 for diagonal. Therefore, in such a situation, the maximum sensing route in the diagonally wired touchscreen is only 57% as long as the maximum sensing route in a touchscreen with an x/y layout.
Positions of the touch sensor in which the first set of conductive sensing elements seamlessly crossover and form sensing nodes with the second set of conductive sensing elements can be considered as merge points.
The touch sensor 700 of
In this example, a printed circuit board is provided in the first edge region 712. The conductive sensing elements are connected to the PCB and extend through the sensing region. The connections within the first edge region 712 may be provided by traces on the PCB.
The touch sensor 800 of
As described previously, it will be appreciated that the touch sensor 900 may be formed by drawings a track for a larger touch sensor and dividing it in two. These two halves can then be joined together, off screen, by a thin flexible, low resistance PCB, and routed to one common connector.
The touch sensor of
In the arrangement of the touch sensor described previously with reference to
The original diagonal 1:1 touchscreen could be cut down into thirds or quarters, each being merged side by side to form one long touchscreen, the height of the sensing element being reduced further at each step. In this way, triplets, quadruplets or any plurality of sensing elements can be connected together for a corresponding number of sets of sensing elements.
In general, the crossing wires are transverse at the point where they cross but are not necessarily perpendicular to one another. Instead of the conductive elements crossing at 90 degrees, they could cross at other angles, such as 60 degrees. This would reduce the aspect ratio and reduce the length of the sensing elements from 1.414 times the minimum dimension (or height) of the screen to 1.2 times the minimum dimension (or height). They could also be aligned asymmetrically to the edges of the screen. These diagrams illustrate some, but not all of the wide range of connectors, connector positions, and node variations possible with this layout.
For example, in a standard 1:4 aspect ratio x/y wired touchscreen, the horizontal sensing elements would all be 4 units long, whereas in this 1:4 aspect ratio diagonal touchscreen, all the sensing elements are 1.414 units long.
There is a 41% increase in the resistance of the shortest sensing elements in an x/y touchscreen, and a 65% reduction in the resistance of the longest touch sensing elements.
If this touchscreen was 1 metre high by 4 metres long, and each of the sensing elements was 1 cm wide, then the maximum resistance of a metal mesh sensing element (at 15 ohms/square) would be 141.4 cm×15 ohms (2.1 Kohms), whereas its resistance, in a standard x/y touchscreen, would be 400 cm×15 ohms (6 Kohms).
Such a touchscreen would be functional using the extended diagonal wiring method but may be unworkable using the standard x/y wiring method.
In practice, however, the signal has to pass along the transmitting element and back through the receiving element. The maximum route of the signal, in the above 1×4 metre touchscreen would, therefore, be 2.828 (1.414+1.414) metres in the diagonally wired touchscreen and 5 (1+4) metres in the x/y touchscreen, an improvement in favour of the diagonal touchscreen of 44%.
When the conductive elements are “looped” as shown in
For higher aspect ratio touchscreens, if the height of the touchscreen stays the same, but the length increases, the resistance of the sensing elements in the diagonal system stays constant at 1.414×the height of the touchscreen. This means that the touchscreen can be extended, almost indefinitely with no resistance problems restricting further extension. Therefore a touchscreen could be 30 or more metres long and would still work well. In this example, with a height of 1 metre and a length of 30 metres, but without “looped” conductive elements, the resistance ratio comparing diagonal layout with x/y layout is would be 2.828 vs 31—a 91% reduction in the resistance. With “looped” conductive elements, the resistance of the diagonal conductive elements is only 4.5% of the resistance of its x/y equivalent.
This shows that the “extended diagonal” wiring method disclosed herein may be used to provide large scale functional touch screens, almost without limitation in terms of length.
Metal mesh film can be purchased with the mesh already printed on both sides of a single film, already slightly offset, one surface against the other and with tracks already etched in the desired pattern, at right angles to each other. At the left and right edges of the screen, the top and bottom tracks need to be joined together electrically, in the appropriate positions, by “cutting” or drilling a small hole in the film and filling this hole with clear conductive ink. This same process can be used for connecting already linked conductive elements where they cross over each other at the top edge of the screen.
The metal mesh patterning can be laser ablated along the bottom edge of the screen and the remaining non-conductive plastic base layer can be ink-jet, 3d printed, or screen printed, with conductive ink traces, which join appropriate tracks together including those going to the connector. Any tracks that run over other tracks can be insulated from each other by over-printing the cross-over points with non-conductive dielectric ink.
The manufacturing method is much simpler when using fine insulation coated wire, as the wires can run over each other at the intersections without short circuiting. The wire may be enamel coated copper or tungsten, for example. The wire may have a diameter range from 5 microns to 50 microns or more, and more preferably from 3 microns to 17 microns, if it is to be invisible to the eye.
A method for forming a wire structure was disclosed in WO 2015/185879 A1, incorporated herein by reference in its entirety.
All the wires may be provided on the same surface, so there is no need to change surfaces at the edges. At the expense of increasing the resistance of the sensing elements, the tracks in the touchscreen can run directly to the connector, with each wire joining, at roughly its mid-point, to a single terminal pin. This eliminates the need for an inter-connecting PCB.
Wire touchscreens are readily truncated, if required, as shown in
Looping the wire like this this has the major beneficial effect of halving the resistance of the conductive sensing elements.
Wires at the right and left edges of the screen do not have routes back through the “sensing region” and so have to travel back to their respective terminal pins through an extended “not touch sensing regions” at the edges of the screen, in the third and fourth edge regions 1416 and 1418 in this example. In this way, all the wires in the screen form loops, thereby halving their resistance.
A method and apparatus for forming a wire structure are disclosed in GB2541336A (Binstead). As a modification to that method, a drum plotter, as opposed to a flatbed plotter, could be used to plot wires onto a cylinder, forming a touch sensing cylinder.
A feature of this arrangement is that, by connecting the third and fourth edge regions seamlessly together in a cylinder, a continuous touch sensing cylinder is formed:
By providing all conductive edges originating at the first edge, the touch sensor can be readily formed into a three dimensional shape (in the Cartesian coordinate system), such as a cylinder.
The conductive sensing elements may be inkjet printed directly onto the touch-screen film, which would make the touch sensor simpler to manufacture than having a separate flexible PCB.
Although there is not normally a resistance problem with LED and Keypad arrays, the diagonal wiring methods used in this patent application apply to them as well. Due to the diagonal layout providing more unique cross-over nodes for a fixed number of inputs/outputs, a simpler wiring layout, with less connectors, all connections being along one edge only, as well as reduced resistance. Instead of providing a touch sensor with sensing nodes, a similar conductor pattern can be used to power LEDs at the position of the sensor nodes. If these arrays become very large, then resistance could start to become a problem. The methods described in this application may resolve such issues.
An added advantage of LEDs is that they only conduct in one direction. This means that the diagonal wiring method can address twice as many LEDs simply by having two oppositely conducting LEDs fitted at each and every intersection. A 7 output LED driver can then independently address any or all of 42 separate LEDs during a single scan.
As with touch sensors, led displays can be extended almost indefinitely if using the diagonal layout described herein, as track resistance does not increase with length.
These LEDs could form a very large, long LED Display, as used in Video Walls. These would work well with the touchscreen sensors described in this patent application, forming a continuous Touch Interactive Video Wall with no visual or touch sensing breaks that are often associated with commonly used tiled LCD Displays and multiple smaller discrete touchscreens.
If keys are fitted in series with diodes and arranged in opposing pairs at every intersection, then any one or all of 42 keys in such a diagonally wired keypad array, could be sensed by 7 inputs. In this way, LED and Keypad arrays can be connected with diagonal wiring, thereby reducing the number of inputs or outputs required.
For example, if two oppositely orientated LEDs 2021, 2022 are sited at otherwise seemingly ambiguous corresponding intersections they can each be illuminated separately by reversing the power supply polarity on the associated connector pins. If output 4 is positive and output 6 is negative, then LED12021 will light up. If output 4 is negative and output 6 is positive, the LED22022 will light up. Neither LED 2021, 2022 will light up for any other combination of outputs.
If a switch was placed in series with led1, and another switch was placed in series with led2, then, if either, both or neither switch is pressed, it is possible to detect exactly which switches have or have not been pressed, by detecting if current flows, or not, under suitable power supply conditions. For example, if output 4 is positive and output 6 is negative, then detectable current will flow if the switch, in series with led1, is pressed. if that switch is not pressed then no current will be detected. Whether the switch, in series with LED2, is pressed or not, makes no difference, as, under these circumstances, no current can flow due to led2 being orientated in the wrong direction.
A similar, but reverse situation occurs if output 4 is negative and output 6 is positive. this time only the switch connected in series with LED2 will be detectable, while whatever happens to the switch connected to LED1, it will have no effect. If used simply as a switch array, then then simple diodes can be used instead of LEDs. under these circumstances, due to there being absolutely no ambiguity, each conductive element can cross any of the other conductive elements twice. if it is possible that three or more conditions have to be met before a switch is detected, or in effect is enacted, then each conductive element can be allowed to cross any of the other conductive elements three or more times.
Furthermore, in
The sides of the wiring layout 2000 may be joined to form a substantially cylindrical conductive array.
In an alternative example, one or more light detectors may be sited among LEDs of an LED display (e.g., on one or more conductive element cross-over points) and configured to detect light reflected from the conductive elements. The one or more light detectors may be implemented alongside touch sensors, e.g., as described in relation to
The wiring layout 2200 is the same as for the touch sensor of
When the wiring layout 2200 is not used to sense touch, voltage signals may be applied to the various connector pins. If two wires at any intersection, e.g., the wires coupled to pins 1 and 6, have a sufficiently high voltage difference between them, this will cause the corresponding electro-luminescent phosphor dot 2231 to glow. The higher the voltage difference, the brighter the dot glows. The display can be scanned in the same way as a touchscreen is scanned, causing the whole screen to act as a display.
This shows how our wiring layout can be used to create a dual function screen, with touchscreen and low resolution display, all addressed from the same 7 pin connector. The connector pins must be inputs some of the time and outputs at other times. The layout is similar to that illustrated in
In the embodiments of
Previously presented embodiments have shown how diagonal conductive elements can be used to increase a number of intersections in a matrix, and/or reduce the number of connections required. These connections can be single conductive elements, conductive elements split into separate sensing elements or a combination of these may be used. The matrices of conductive elements may have terminations at the end or be looped to form a tube. The length of the conductive elements in the active area of the matrix is dependent on the height of the matrix but, beyond a certain point, is independent of the matrix's width. If the conductors are at right angles to each other in a diagonal arrangement, such as in the embodiments disclosed herein, then the maximum conductor length is about the square root of two (1.414) times the height of the matrix. This means that, no matter how wide the matrix gets, after a certain point, the conductors do not get any longer and their resistance is constant.
The conductive elements of the first, second and third pluralities of conductive elements cross at 90 degrees to each other to define a sensing area in this example. That is, the conductive elements that cross one another extend in perpendicular directions.
The wiring layout shown in
The layout of the first and third pluralities of conductive elements is generally similar to the layout of the conductive elements shown in
The touch sensor 2500 further shows electrical connectors ‘Con1’ 2540 and ‘Con5’ 2541. These electrical connectors may have the same connections as each other, or be connected together so as to form pairs of conductors. Furthermore, the electrical connector for each instance of a second plurality of conductive elements connects to the bulk of the sensing elements. All the connectors may be connected to a single processor. Alternatively each connector may be connected to a separate processor, or any combination in between. These processors may be totally synchronised, or work semi-independently, or work totally independently some of the time. Irrespective of the width of the sensing region, the maximum length of any conductors in the active area is the square root of two (1.414) multiplied by the height of the sensing region, even though the width of the matrix may be many times greater than this. More electrical connectors can be added or subtracted in order to either lengthen or shorten the touch sensor without changing the length of any of the conductor elements as originally provided. In this embodiment, the conductive elements of Con 22542 do not overlap with those of Con 42543. This enables the conductors of these two connectors to work independently without any detrimental consequences for the functioning of the overall touch sensor. As such, a touch sensor comprising connectors that can be attached to the same or different controllers can be provided, so long as they can synchronise with their immediate neighbours. These advantages are not realised in x/y arrangements such as that shown in
As shown in
As shown in the upper portion of
The lower half of a cylinder 2702 such as that shown in
All possible intersections are available if an odd number of inputs (conductive elements) is used, such as seven inputs which would give 21 intersections. In this example, the conductive elements extend onto the sensing region at a first edge (edge B-B of
By providing three-dimensional touch sensors such as those shown in
Throughout the present specification, the descriptors relating to relative orientation and position, such as “height”, “width”; “horizontal”, “vertical”, “top”, “bottom” and “side”, are used in the sense of the orientation of the touch sensor or touch screen as presented in the drawings. However, such descriptors are not intended to be in any way limiting to an intended use of the described or claimed invention. Touchscreens are often used as table tops. In such a situation, the word height can be read as width.
It will be appreciated that any components that are described or illustrated herein as being coupled or connected could be directly or indirectly coupled or connected. That is, one or more components could be located between two components that are said to be coupled or connected whilst still enabling the required functionality to be achieved.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2112315.3 | Aug 2021 | GB | national |
| 2113191.7 | Sep 2021 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/GB2022/052206 | 8/26/2022 | WO |
