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    • 专利摘要:
    A touch screen (1) for detecting the location of a touch (P), the touch screen (1) comprising: a continuous resistive assembly (3) for determining a first touch location, a capacitive assembly (4) for determining of a second touch location, and a control device (5a, 5b) electrically connected to the resistive assembly (3) and the capacitive assembly (4), the control device (5a, 5b) switching the touch screen (1) alternately between resistive detection mode, wherein the controller (5a) drives the resistive assembly (3) to determine the first touch location while the capacitive assembly (4) is inactive, and a capacitive detection mode, wherein controller (5b) drives the capacitive assembly (4) to determine the second touch location while the resistive assembly (3) is inactive, and wherein the controller (5a) further drives the resistive assembly (3) such that the resistive assembly (3) is used as a powered shield for the capacitive assembly (4) when the touch screen (1) is in capacitive detection mode.
    公开号:BE1027408B1
    申请号:E20195429
    申请日:2019-07-03
    公开日:2021-02-02
    发明作者:Luc Demets
    申请人:Clicktouch；
    IPC主号:
    专利说明:

    IMPROVED TOUCH SCREEN FOR DETECTING THE
    LOCATION OF A TOUCH Technical domain The present invention relates to an improved touch screen for detecting the location of a touch by combining a resistive and a capacitive assembly for measuring a touch location. The present invention further relates to a method of confirming a touch. Background Art Touch screens have become particularly popular in a variety of applications, such as tablets, operating screens, or mobile phones, and in a wide variety of fields, such as in industry or medicine. Especially since the launch of Apple's iPhone, capacitive touch screens have become very popular, and they are more and more used today. Capacitive touch screens can be divided into touch screens using assemblies for measuring surface electrical capacitance and touch screens using assemblies for measuring projected capacitance, such as assemblies for measuring self-capacitance or mutual capacitance. Each type of assembly has its advantages and disadvantages, and the use of a particular assembly therefore depends strongly on the desired application. However, it has become common in the industry to use assemblies for measuring projected capacity. Despite their overall attractive features, capacitive touch screens generally have one major drawback. An undesired, e.g. accidental or unintended sensing of a touch at a particular location of the touch screen can easily occur, since no interaction force is required to detect a touch on the touch screen. If the touch screen is approached too closely with a conductive object, it may cause contact. Especially in applications where the user does not look at the touch screen 100% of the time (for example, in industrial applications such as metalworking machines, or as in medical applications such as medical equipment where the operator has to keep an eye on multiple devices and / or the patient), an accidental touch can easily occur, for example by a finger hovering "hesitantly but ready to touch it" above the touch screen, or by involuntary arm movement. An even more important mechanism that leads to unwanted touches is formed by liquids such as water and / or dirt that gets on the touch screen. Conductive liquids, such as sweat or blood, in particular, remain a major cause of unwanted contact on the capacitive assemblies.
    It has been found in the prior art that the problem of unwanted touches can be addressed by increasing the redundancy of the touch screen. In particular, it has been proposed in the prior art to provide a second measuring assembly that independently of the capacitive measuring assembly determines the location of the touch on the touch screen, for example to confirm that the user actually wishes to activate / touch the touch screen. by touching the touchscreen at that particular location. It has been found that the touch detection technology of the second measurement assembly should preferably be different from the touch detection technology of the capacitive measurement assembly, in order to ensure that a single cause of unwanted touch does not lead to the determination of a contact location in both measurement assemblies. For example, in US patent US20120188187 a touch screen is disclosed in which a resistive measurement assembly, hereinafter referred to as a resistive assembly, and a capacitive measurement assembly, hereinafter referred to as a capacitive assembly, are placed on top of each other.
    In the touch screen disclosed in US20120188187, the resistive assembly and the capacitive assembly are simultaneously driven to simultaneously obtain a first and a second touch location by the resistive and capacitive assembly, respectively. A location of a touch is confirmed when the first and second touch locations are almost the same.
    Furthermore, it is preferred that the resistive assembly of the touch screen provides a continuous determination of a touch location, that is, the determination of the location of a touch is not discrete as would be the case if the resistive assembly did not include electrode layers such as resistive films, but instead discrete electrode strips that form an XY grid of electrodes. A continuous determination of a touch location makes it possible to determine a touch more precisely and accurately. In addition, the continuous determination of the touch location makes it possible to determine a continuous movement of a location of a touch in a smoother manner. A resistive assembly that allows for such a continuous determination of a touch location is called a continuous resistive assembly. Such a continuous resistive assembly includes an upper electrode layer located relatively close to the user and a substantially parallel lower electrode layer located relatively far from the user, a location of a touch being inferred from the contact position of the upper electrode layer and the lower electrode layer.
    Examples of continuous resistive assemblies are commercially available 4-wire, 5-wire or 8-wire resistive assemblies.
    However, in the present invention, it has been found that when the resistive assembly and the capacitive assembly are superimposed only, especially when the resistive assembly is a continuous resistive assembly such as a 4-wire, 5-wire or 8-wire assembly, the performance delivered is sub-optimal. to be.
    In the present invention, it has been found that the resistive assembly, particularly the relatively large electrode layers such as those present in continuous resistive assemblies, in contrast to the discrete electrode strips forming an XY grid of electrodes, acts as a ground plane, which makes normal functioning of the capacitive assembly difficult or impossible.
    In particular, it has been found that the ground plane creates parasitic capacitances with the electrodes of the capacitive assembly, limiting the resolution at which a change in the capacitance value is detected on the detectors of the capacitive assembly.
    Description of the Invention
    It is an object of the present invention to provide an improved touch screen for detecting the location of a touch independently by a resistive assembly and a capacitive assembly, in particular by a continuous resistive assembly, such as, but not limited to, a resistive assembly with 4 wires, 5 wires or 8 wires, and a capacitive assembly such as preferably a capacitive assembly for measuring projected capacitance.
    The improved touch screen of the present invention thus comprises a resistive assembly for determining a first touch location, a capacitive assembly for determining a second touch location, and a controller for driving the resistive and capacitive assembly, i.e., for determining respectively the first and second touch locations.
    The capacitive assembly is provided on top of the resistive assembly, for example, between the resistive assembly and an input surface of the touch screen.
    The input surface of the touch screen is, for example, a surface that is substantially accessible by a user, for example by accessing the surface with the user's finger,
    to provide an input to the touch screen.
    The input surface, i.e. the surface of the touch screen configured to be touched by the user, is formed, for example, by the capacitive assembly itself, or is, for example, formed by a thin, scratch-resistant coating applied on top of the capacitive assembly.
    Preferably, the touch screen is configured to determine the first and second touch locations on the input surface of the touch screen ... In the present invention, the "first touch location" and the
    "Weath touch location" to the "calculated locations" on the touch screen, as determined by the resistive assembly and the capacitive assembly, respectively.
    These "calculated locations" are approximations of a "physical location" that the user touches on the touch screen, for example, at a physical location on the input surface, such as by touching the input surface with a finger. These "calculated locations" are preferably approximations of a single "physical location" that the user touches on the touch screen, for example a single physical location on the input surface, for example by touching the input surface with a single finger. In other words, the "first touch location" and the "second touch location" preferably do not relate to the multiple touch locations in a "multitouch" application, where the touch screen is touched simultaneously in different locations, for example with multiple fingers. The controller is electrically connected to the resistive assembly and the capacitive assembly. The resistive assembly includes a lower electrode layer, e.g., a lower resistive film, and a substantially parallel upper electrode layer, e.g., an upper resistive film, located, for example, between the lower electrode layer and the input surface.
    Preferably, the top electrode is closer to the user, e.g., closer to the input surface, than the bottom electrode. Preferably, the top electrode layer is substantially parallel to the input surface of the touch screen. The first touch location can be derived, for example, by the controller driving the resistive assembly, from the contact position of the upper electrode layer and the lower electrode layer. The resistive assembly is preferably provided as a continuous resistive assembly, i.e. the determination of the location of a contact by the resistive assembly is preferably not discrete, as would be the case if the resistive assembly is not electrode layers such as resistive films but discrete, in comprised one-way electrode strips forming an XY grid of electrodes. A continuous determination of a touch location makes it possible to determine a touch more precisely and accurately. In addition, the continuous determination of the touch location makes it possible to determine a continuous movement of a location of a touch in a smoother manner. Preferably, for example after a given period of time determined by, for example, a scan frequency, the controller stores the first touch location determined by driving the resistive assembly and the second touch location determined by driving the capacitive assembly.
    Preferably, the controller generates an acknowledgment signal when the first touch location is substantially the same as the second touch location. The improved touch screen of the present invention therefore offers the advantage that the location of the touch, for example, on the input surface of the touch screen is independently determined by a capacitive assembly and by a resistive assembly, in particular by a continuous resistive assembly. By providing both the continuous resistive assembly and the capacitive assembly, the redundancy of the touch screen is increased. This increase in redundancy preferably makes it possible to confirm that the user really wants to activate / touch the touch screen by touching the touch screen, at that particular location, for example by the first touch location, which is determined by the touch screen. resistive assembly, comparable to the second touch location determined by the capacitive assembly.
    According to one embodiment of the present invention, the controller alternates the touch screen between a resistive detection mode, wherein the controller drives the resistive assembly to determine the first touch location while the capacitive assembly is inactive, i.e., while the capacitive assembly is not driven to the second touch location. and a capacitive detection mode, wherein the controller drives the capacitive assembly to determine the second touch location while the resistive assembly is inactive, ie, while the resistive assembly is not driven to determine the first touch location. It has been found that switching the touch screen between capacitive detection mode and resistive detection mode reduces the interference from one measurement modality, such as the resistive measurement modality, to the other measurement modality, such as the capacitive measurement modality. In accordance with one embodiment of the present invention, the controller further drives the resistive assembly such that the resistive assembly is used as a powered shield for the capacitive assembly when the touch screen is in capacitive detection mode. The driven shield is also known as a capacitive driven shield. The relatively large electrode layers provided in continuous resistive assemblies, unlike discrete electrode strips that form an XY grid of electrodes in discrete resistive assemblies, have been found to act as a ground plane that makes normal operation of the capacitive assembly difficult or even impossible. . Namely, it has been found that this large ground plane creates parasitic capacitances with the electrodes of the capacitive assembly, limiting the resolution at which a change in the capacitance value in the capacitive assembly is detected. By driving the resistive assembly, for example by driving the lower and / or upper electrode layer, as a capacitive driven shield for the capacitive assembly, the parasitic capacitances between the ground plane and the electrodes of the capacitive assembly are reduced. Furthermore, it has been found in the present invention that the advantage of the present embodiment applies to all touch screens in which continuous resistive assemblies and capacitive assemblies are superimposed on each other, regardless of the further application of the first and the second touch location, one of the applications being the determining is from an acknowledgment signal to confirm a location of a touch on the touch screen.
    According to an embodiment of the present invention, the location of the touch is confirmed when the first touch location determined by the continuous resistive assembly is substantially equal to the second touch location determined independently by the capacitive assembly.
    According to the embodiment of the present invention, the controller stores the first touch location, which is determined by driving the resistive assembly during the resistive detection mode, and the second touch location, which is then determined by subsequently driving the capacitive assembly during the capacitive mode. detection mode.
    The control device comprises, for example, a memory component for temporarily storing the determined touch locations.
    Preferably, the control device generates an acknowledgment signal when the first touch location is substantially equal to the second touch location.
    For example, the acknowledgment signal switches an internal machine state stored in the memory component of the control device, where the internal machine state is associated, for example, with the last measured first and second touch locations, and the internal machine state is `` not acknowledged '' by default, and the acknowledgment signal for example, the internal machine state switches to 'confirmed'. The touch screen is preferably connected to a user device, such as a mobile phone, an ATM or a hob.
    Preferably, the user equipment is enabled to retrieve the first and second touch locations when the associated internal machine state is "confirmed".
    In accordance with one embodiment of the present invention, the resistive assembly comprises an upper substrate, preferably a flexible upper substrate, with the upper electrode layer, and a lower substrate, preferably a rigid lower substrate, with the lower electrode layer.
    Preferably, the top substrate is closer to the user, e.g., closer to the input surface, than the bottom substrate.
    Preferably, the top and bottom electrode layers are resistive films, such as films made of ITO alloy.
    The top substrate and the bottom substrate are preferably positioned with respect to each other in such a way that the top electrode layer faces the bottom electrode layer.
    The resistive assembly preferably further includes a plurality of spacer points located between the top substrate and the bottom substrate to separate the top electrode layer from the bottom electrode layer.
    For example, the plurality of spacer points keeps the top and bottom electrode layers separate from each other unless a user presses, i.e. forcibly moves, the top substrate with the top electrode layer toward the bottom electrode layer, creating a contact point between the top and the lower electrode layer.
    The plurality of spacer points are preferably electrical insulators.
    As a result, for example, the upper electrode layer and lower electrode layer are not electrically connected unless a user presses the flexible substrate with the upper electrode, i.e. forcibly displaced it in the direction of the lower electrode, creating an electrical connection between the upper and lower electrodes. bottom electrical layer.
    For example, the electrical connection formed between the upper electrode layer and the lower electrode layer makes it possible to determine that a user has touched the touch screen, for example at the input surface.
    For example, the change in electrical parameters, such as the change in voltage or current, that occurs due to the formation of the electrical connection formed between the upper electrode layer and the lower electrode layer makes it possible to determine the location where a user touch screen , for example, where the user touched the input surface.
    The operation of the continuous resistive assembly will be further explained below with regard to the specific embodiments of the 4 wire, 5 wire or 8 wire resistive assemblies.
    According to one embodiment of the present invention, during the resistive detection mode, the controller applies unidirectional voltage drops to the upper electrode layer of the resistive assembly and / or the lower electrode layer of the resistive assembly.
    The present embodiment clarifies the operation of known continuous resistive assemblies such as 4-wire, 5-wire or 8-wire continuous resistive assemblies.
    In a first embodiment, the resistive assembly is a four-wire resistive assembly, the controller driving the resistive assembly during the resistive detection mode, by alternately applying a unidirectional voltage drop to the upper electrode layer of the resistive assembly while detecting the lower electrode layer. and a perpendicular unidirectional voltage drop on the lower electrode layer of the resistive assembly while the upper electrode layer is detected.
    Preferably, the upper electrode layer is in electrical contact with two conductive wires extending substantially parallel to each other in a first direction, for example at positions + x and -x, for example along opposite edges of the upper electrode layer.
    Preferably, the lower electrode layer is in electrical contact with two conductive wires that extend substantially parallel to each other in a second direction substantially perpendicular to the first direction, for example + y and -y, for example along opposite edges of the lower electrode layer.
    The controller is arranged to alternately apply a voltage drop between the + x and -x wires (at a first time) and between the + y and -y wires (at a next time). When the upper and lower electrode layers come into contact with each other as a result of a touch by a user with sufficient force, the x position of the touch, for example, on the input surface, is determined while a voltage drop is applied between the + x and the -x- wire, and the voltage at the contact point is measured by the -y- and / or the + y wire,
    i.e., the top electrode layer acts as a voltage divider.
    Similarly, the y position of the touch, for example on the input surface, is determined while a voltage drop is applied between the -y and + y wires, and the voltage at the contact point is measured by the + x and / or the -x wires, ie the bottom electrode layer acts as a voltage divider.
    In a second embodiment, the resistive assembly is a five-wire resistive assembly, the controller driving the resistive assembly during the resistive detection mode, by alternately applying a unidirectional voltage drop to a driven electrode layer comprising one of the top or bottom electrode layers of the the resistive assembly while the other electrode layer of the resistive assembly is detected, and a perpendicular unidirectional voltage drop on the driven electrode layer while the other electrode layer of the resistive assembly is detected.
    Preferably, the five wire resistive assembly is a resistive assembly wherein the controller drives the resistive assembly during the resistive detection mode, alternately applying a unidirectional voltage drop to the lower electrode layer of the resistive assembly while detecting the upper electrode layer and a perpendicular unidirectional voltage drop on the lower electrode layer of the resistive assembly while the upper electrode layer is detected.
    The preferred embodiment, where the bottom electrode layer is the driven electrode layer, offers the advantage that the touch screen is more resistant to scratch / cut damage.
    Namely, it has been found that when the touch screen is scratched / cut, the scratch / cut is usually applied through the input surface of the touch screen, and thus extends from the input surface in the direction of the resistive assembly.
    As a result, the upper electrode layer is more subject to scratch / cut damage than the lower electrode layer.
    By providing the lower electrode layer as the driven electrode layer, the resistive touch screen can continue to function normally even when the upper electrode layer is scratched / damaged.
    Preferably, in the five-wire resistive assembly, the driven electrode layer, preferably the lower electrode layer, is in electrical contact with the control device via four conductive wires, forming, for example, a substantially rectangular structure forming a + x-, a -x-, a + y and a -y wire, provided, for example, along four substantially perpendicular edges of the driven electrode layer, preferably of the lower electrode layer. The other electrode layer of the resistive assembly i.e. the electrode layer of the resistive assembly which is not the driven electrode layer i.e. the electrode layer of the resistive assembly not having the + x-, the -x-, the + y- and the -y wire is preferably in electrical contact with at least one sensing conductor connected to the control device. The control device is arranged to alternately apply a voltage drop between the + x and -x wires (at a first time} and between the + y and -y wires (at a next time). and the lower electrode layers come into contact with each other as a result of a touch by a user with sufficient force, the x position of the touch, for example, on the input surface, is determined while a voltage drop is applied between the + x- and the -x wire, and voltage at the point of contact is measured by the sensing conductor, ie the driven electrode layer acts as a voltage divider. Similarly, the y position of the touch, for example on the input surface, is determined while a voltage drop is applied between the - y and the + y wire, and the voltage at the contact point is measured by the sensing conductor, ie the driven electrode layer acts as a voltage divider. In a third embodiment, the resistive sa Make a resistive assembly with 8 wires. 8-wire resistive assemblies work like 4-wire resistive assemblies, but have four additional detection lines, allowing for better accuracy and linearity in larger touch screen sizes.
    In one embodiment of the present invention, the capacitive assembly includes electrodes that are physically distinct from the lower or upper electrode layer of the resistive assembly. For example, the electrodes of the capacitive assembly are a grid of perpendicular X and Y electrode strips in capacitive assemblies utilizing projected capacitance measurement principles. Preferably, the controller drives the resistive assembly such that the resistive assembly is used as a powered shield for the capacitive assembly when the touch screen is in capacitive sensing mode, through the upper and / or lower electrode layer (s) of the resistive assembly such that the upper and / or lower electrode layer (s) of the resistive assembly is / are used as a powered shield for the capacitive assembly, i.e. one or both of the upper and lower electrode layers of the resistive assembly shielding electrode layers.
    In one embodiment, at least the upper electrode layer of the resistive assembly is driven to act as a powered shield for the capacitive assembly, i.e., at least the upper electrode layer is a shielding electrode layer because the upper electrode layer of the resistive assembly is adjacent to the capacitive assembly and therefore tends to create the most parasitic capacity.
    Preferably, only the top electrode layer of the resistive assembly is driven to act as a powered shield for the capacitive assembly, i.e., only the top electrode layer is a shielding electrode layer, reducing the complexity of the resistive assembly while providing a sufficiently strong powered shield. .
    According to one embodiment of the present invention, the controller drives the resistive assembly in such a way that the resistive assembly is used as a powered shield for the capacitive assembly when the touch screen is in capacitive sensing mode, by applying a voltage Vprotection to the upper and / or the lower electrode layer of the resistive assembly.
    Note that the choice of electrode layers of the resistive assembly to be driven as a powered shield (by applying V-shield) has been discussed above.
    In accordance with one embodiment of the present invention, the voltage Vprotection is substantially equal to the voltage that the controller applies to the capacitive assembly when the capacitive assembly is being driven.
    Thus, the applied voltage V protection essentially follows the voltage applied to the capacitive assembly, for example because the controller drives the capacitive and resistive assemblies simultaneously with the same voltage, or because the controller couples a voltage buffer / voltage follower between the capacitive and the resistive. assembly.
    The voltage applied to the capacitive assembly, and consequently V protection, is usually a high frequency AC voltage, for example, on the order of 1 MHz.
    When the voltage difference between the shield electrode layer and the electrode of the capacitive assembly is minimized, it generally minimizes the amount of parasitic capacitance.
    According to a preferred embodiment of the present invention, the capacitive assembly is a measuring assembly for measuring projected capacitance.
    Measurement assemblies for measuring projected capacitance include, for example, X-
    electrode strips extending in a first direction and Y electrode strips extending in a second direction substantially perpendicular to the first direction to form an electrode grid.
    Preferably, the X electrode strips form a plane which is substantially parallel to a plane formed by the Y-
    b electrode strips.
    For example, both planes are parallel to the input surface of the touch screen.
    Preferably, the electrode strips are distinct from the top electrode layer of the resistive assembly, and are, for example, parallel to the top electrode layer of the resistive assembly.
    Projected capacitive assemblies have become the industry standard at the expense of surface capacitive assemblies.
    However, in the present invention, it has been found that a touch screen in which a resistive assembly and a projected capacitive assembly are superimposed, as opposed to a surface capacitive assembly, is particularly susceptible to parasitic capacitance when the capacitive assembly is driven.
    Thus, such a touch screen greatly benefits from the advantage of providing the powered capacitive protection of the present invention.
    In accordance with one embodiment of the present invention, the electrodes of the resistive assembly and the capacitive assembly are substantially transparent to visible light.
    Preferably, the electrodes of the resistive assembly and the capacitive assembly are made of an indium-tin oxide (ITO) alloy. The "electrodes of the resistive assembly" refer specifically to the electrode layers of the resistive assembly.
    Specifically, the "electrodes of the capacitive assembly" refer to the X and Y electrode strips that form the electrode grid in a measuring assembly for measuring projected capacitance.
    The present embodiment is particularly interesting when visual indicators are provided below the touch screen, because the electrodes, especially electrodes made of ITO alloy, will then not interrupt to any significant extent the visible light emanating from the visual indicators.
    The visual indicators are, for example, static indicators or, preferably, dynamic indicators.
    Preferably, the touch screen is mounted on top of a display that is configured, for example, to display the indicators, for example via a conventional graphical user interface.
    Preferably, the touch screen includes a support such as a glass plate or a Plexiglas plate provided between the visual indicator and the lower electrode layer of the resistive assembly.
    In one embodiment, the rigid substrate with the lower electrode layer of the resistive assembly is the support (e.g., fabricated as ITO glass). In a second embodiment, the rigid substrate with the lower electrode layer of the resistive assembly is attached to the support by means of an optically transparent adhesive (e.g., made as an ITO film glued to glass). The substrate with the lower electrode layer of the resistive assembly is called a rigid substrate layer because it prevents the lower electrode layer from moving when the upper electrode layer is pushed towards it, allowing the lower and upper electrode layers to touch.
    The substrate with the lower electrode layer of the resistive assembly is a rigid layer, for example because the substrate itself is made of a rigid material or because the substrate is provided on a rigid substrate, such as on the support.
    According to an embodiment of the present invention, the touch screen input surface is a surface configured to be touched by a user.
    In a first embodiment, the substrate with the capacitive assembly has electrodes on one of its surfaces, having an opposite surface that acts as the input surface.
    In a second embodiment, the substrate with the capacitive assembly has electrodes on one of its surfaces, having an opposing surface to which a front layer is disposed, with the free surface of the front layer acting as the input surface.
    Preferably the front layer is somewhat flexible, transparent to visible light and optionally scratch resistant.
    The front layer is preferably made of (thin) glass, polycarbonate or PET.
    Preferably, the front layer is attached to the substrate with the electrodes of the capacitive assembly by means of an optically transparent adhesive layer.
    An additional object of the present invention is to provide a method of confirming a touch at a location on the touch screen, for example at a location on an input surface of the touch screen, the method comprising the steps of providing a touch screen. as described above,
    e driving the resistive assembly by means of the controller to obtain a first touch location while maintaining the capacitive assembly in an inactive state,
    e driving the capacitive assembly by means of the controller to obtain a second touch location while maintaining the resistive assembly in an inactive state and simultaneously driving the resistive assembly to use the resistive assembly as a powered shield for the capacitive assembly,
    e generating an acknowledgment signal by means of the control device when the first touch location is substantially the same as the second touch location.
    Preferably, the steps of obtaining the first touch location, obtaining the second touch location, and generating the confirmation signal are performed repeatedly, for example with a scan frequency of at least 10 Hz, preferably at least 20 Hz, more preferably at least 50 Hz.
    Figures Figure 1 is an exploded perspective view of an embodiment of the touch screen of the present invention.
    Figure 2 is a cross-sectional view of an embodiment of the touch screen of the present invention.
    Brief Description of the Figures The present invention is described with reference to specific embodiments and with reference to certain illustrations; however, it is not limited to this.
    The illustrations described are only schematic and are non-limiting.
    In the illustrations, the size of some elements may be enlarged for illustrative purposes and not drawn to scale.
    The dimensions and relative dimensions do not necessarily correspond to actual practical embodiments of the invention.
    Furthermore, the terms first and second in the specification and claims are used to distinguish between similar elements, and not necessarily to describe a sequential or chronological order.
    The terms are interchangeable in appropriate circumstances, and the embodiments of the invention may function in sequences other than those described or illustrated herein.
    Furthermore, although referred to as "preferred embodiments", the various embodiments are to be understood as examples of ways in which the invention may be carried out, and not as limiting the scope of the invention.
    The term "comprising", used in the claims, is not to be construed as limited to the elements or steps enumerated thereafter; it does not exclude other elements or steps.
    The term is to be interpreted as specifying the presence of said properties, numbers, steps or components as indicated, but does not preclude the presence or addition of one or more other properties, numbers, steps or components, or groups thereof. from.
    The scope of the expression "a device comprising A and B" should therefore not be limited to devices consisting only of components A and B; rather, as for the present invention, the only listed components of the device are A and B, and the claim should further be interpreted as including equivalents of A and B.
    Figure 1 is an exploded perspective view of an embodiment of the touch screen 1 of the present invention. Figure 2 is a cross-sectional view of an embodiment of the touch screen 1 of the present invention, in particular of the touch screen 1 shown in Figure 1. An example of the construction of the touch screen 1 will be explained below on the basis of both Figures 1 and 2. The touch screen 1 is configured to detect the location of a touch 'P' on an input surface 2, for example when the input surface is touched by a user 12. The touch screen 1 comprises a continuous resistive assembly 3 and a capacitive assembly 4 placed on top of each other. The input surface 2 in Figures 1 and 2 is formed by the free surface of a thin, scratch-resistant cover layer applied on top of the capacitive assembly 4.
    The capacitive assembly 4 comprises two substantially parallel flexible planes formed by a series of X electrode strips and a series of Y electrode strips, respectively, to form an electrode grid 8. The X electrode strips and the Y electrode strips are made of an electrically resistive material such as ITO alloy. The two substantially parallel faces of the electrode grid 8 are electrically insulated from each other. The electrode strips of the electrode grid 8 are disposed on one or more flexible substrates (not shown). In Figure 2, the electrode grid 8 can be seen as a single layer, referred to as layer 8, but it should be noted that in practice the electrode grid 8 comprises two substantially parallel planes, as shown in Figure 1. The capacitive assembly 4 is the driver. by a capacitive controller 5b for determining, during a capacitive detection mode, a second touch location 'P' on the input surface 2.
    The resistive assembly 3 comprises a rigid substrate with a lower electrode layer 7, ie a film of electrically resistive material, such as an ITO alloy, and a substantially parallel flexible substrate with an upper electrode layer 6, ie a film of electrically resistive material, such as a ITO alloy. In Figure 2, the flexible substrate and its upper electrode layer 6 are seen as a single layer, together referred to as layer 6, but it should be noted that in practice the upper electrode layer 6 is applied to the lower surface of the flexible substrate . In Figure 2, the rigid substrate and its lower electrode layer 7 can also be seen as a single layer, together referred to as layer 7, but it should be noted that in practice the lower electrode layer 7 is applied to the top surface of the rigid substrate.
    In particular, the upper electrode layer 6 and the lower electrode layer 7 face each other and are separated from each other by a series of electrically insulating spacer points 13. The resistive assembly 3 is drivable by a resistive control device 5a for determining, during a resistive detection mode. , from a first touch location on the input surface 2. The first touch location can be deduced from the contact position of the upper electrode layer 6 and the lower electrode layer 7. In particular, the resistive assembly 3 is a conventional continuous resistive assembly 3 with 5 wires.
    In that 5-wire resistive assembly 3, the resistive control device 5a drives the resistive assembly 3 during the resistive sensing mode, by alternately applying i) a unidirectional voltage drop to the lower electrode layer 7, for example along the x direction, while the voltage on the upper electrode layer 6 is detected, and ii) a perpendicular unidirectional voltage drop on the lower electrode layer 7, for example along the y direction, while the voltage on the upper electrode layer 6 is detected.
    The lower electrode layer 7 is thus in electrical contact with four conductive wires, namely AB, AC, DC and BD, which form an almost rectangular structure forming a + x-, an -x-, a + y- and a -y wire. includes.
    For example, wires AC and BD extend in the x direction, while wires CD and AB extend in the y direction.
    The wires are disposed along the four substantially perpendicular edges of the lower electrode layer 7. The four wires are in electrical contact with the resistive control device 5a.
    Furthermore, the upper electrode layer 6 is provided with at least one detection conductor which is in electrical contact with the upper electrode layer and with the resistive control device 5a.
    The resistive controller 5a is arranged to alternately apply a voltage drop between the + x and -x wires (at a first time) and between the + y and -y wires (at a next time}. the upper and lower electrode layers 6, 7 come into contact with each other as a result of a touch by a user 12 'P' with sufficient force, the x position of the touch 'P' on the input surface 2 is determined while a voltage drop is detected applied between the + x and the -x wire, and the voltage at the contact point 'P' is measured by the detection conductor, ie the lower electrode layer 7 acts as a voltage divider.
    Likewise, the y position of the touch 'P' on the input surface 2 is determined while a voltage drop is applied between the -y- and + y wires, and the voltage at the contact point 'P' is measured by the sensing conductor ie, the lower electrode layer 7 acts as a voltage divider.
    The electrode grid 8 of the capacitive assembly 4 is physically distinct from the upper electrode layer 6 of the resistive assembly 3. An optically transparent adhesive layer 11a is disposed between the electrode grid 8 of the capacitive assembly 4 and the upper electrode layer 6 of the resistive assembly 3. The optical transparent adhesive layer 114 is a flexible layer such that when a user touches the input surface 2, the bending of the electrode grid 8 of the capacitive assembly 4 causes the flexible substrate to bend simultaneously with the upper electrode layer 6 of the resistive assembly 3. substrate with the lower electrode layer 7 of the resistive assembly 3 is called a rigid substrate layer because it prevents the lower electrode layer 7 from moving when the upper electrode layer 6 is bent towards it, thereby allowing the lower and the upper electrode layers 6, 7 to meet touching, ie form an electrical contact.
    The substrate with the lower electrode layer 7 of the resistive assembly 3 is a rigid layer because the substrate is bonded to a rigid substrate by means of an optically transparent adhesive layer 11b, such as on a support 10, which is for example made of Plexiglas.
    The touch screen 1 as described above has an increased redundancy over known continuous resistive touch screens and known capacitive touch screens.
    For example, the increased redundancy can ensure continued operation when one of the touch measurement assemblies fails.
    In a preferred application of the touch screen 1 of the present invention, the redundancy of the touch screen 1 is used to confirm a touch at a touch location "P".
    The method of confirming a touch at a location "P" on an input surface 2 of a touch screen 1 comprises the steps of providing a touch screen 1 as described above,
    e driving the resistive assembly 3 with the resistive control device ba to obtain a first touch location while the capacitive assembly 4 is kept in an inactive state, i.e. while the position is not determined with the capacitive assembly 4,
    e driving the capacitive assembly 4 with the capacitive controller 5b to obtain a second touch location while keeping the resistive assembly 3 in an inactive state, i.e., while the position is not determined with the resistive assembly 3,
    e generating an acknowledgment signal when the first touch location is substantially equal to the second touch location.
    The steps of obtaining the first touch location, obtaining the second touch location and generating the acknowledgment signal are performed repeatedly, for example with a scan frequency of at least 10 Hz, preferably at least 20 Hz, more preferably at least 50 Hz .
    The synchronization between the resistive control device 5a and the capacitive control device 5b is controlled, for example, by a master control device 5m.
    For example, the master controller 5m is configured to temporarily store the first and second touch locations and to generate the confirmation signal when the first touch location is substantially the same as the second touch location.
    According to one embodiment, especially for smaller touch screens 1 such as touch screens 1 smaller than 15 ", the master controller 5m, the resistive controller 5a and the capacitive controller 5b are provided on a single chip.
    According to one embodiment, in particular for larger touch screens 1, such as touch screens 1 that are larger than 15 ”, the control devices are distributed over several chips.
    It has been found that the relatively large electrode layers 6, 7 provided in the continuous resistive assembly 3 of the above-mentioned touch screen 1 act as a ground plane which makes normal functioning of the capacitive assembly 4 difficult or even impossible.
    Namely, it has been found that this large ground plane creates parasitic capacitances with the electrode layer 8 of the capacitive assembly 4, limiting the resolution with which a change is detected in the current in the capacitive assembly 4. The resistive controller 5a of the present invention, for example, which is under the control of the master controller, is therefore arranged to drive the resistive assembly 3 such that the resistive assembly 3 is used as a powered shield for the capacitive assembly 4 when the touch screen 1 is in capacitive detection mode.
    权利要求:
    Claims (12)
    [1]
    A touch screen (1) for detecting the location of a touch (P), the touch screen (1) comprising: a resistive assembly (3) for determining a first touch location, the resistive assembly (3) having a lower electrode layer (7) and a substantially parallel upper electrode layer (6), the first contact location being inferred from the contact position of the upper electrode layer (6) and the lower electrode layer (7), a capacitive assembly (4) for determining from a second contact location, the capacitive assembly (4) being provided on top of the resistive assembly (3), and a control device (Ba, 5b) electrically connected to the resistive assembly (3) and the capacitive assembly (4), wherein the controller (Ba, 5b) alternately switches the touch screen (1) between a resistive detection mode, the controller (Ba) drives the resistive assembly (3) to determine the first touch location and while the capacitive assembly (4) is inactive, and a capacitive sensing mode, wherein controller (5b) drives the capacitive assembly (4) to determine the second touch location while the resistive assembly (3) is inactive, and wherein the controller (5a) ) further drives the resistive assembly (3) such that the resistive assembly (3) is used as a powered shield for the capacitive assembly (4) when the touch screen (1) is in capacitive detection mode by applying a voltage Vprotection to the upper and / or the lower electrode layer (6, 7) of the resistive assembly (3), and wherein the voltage Vprotection is substantially equal to the voltage applied by the control device (Bb) to the capacitive assembly (4) when the capacitive assembly ( 4) is powered.
    [2]
    The touch screen (1) according to the first claim, wherein the control device (Ba, 5b) stores the first touch location, which is determined by driving the resistive assembly (3) during the resistive detection mode, and stores the second touch location, which is then determined by subsequently driving the capacitive assembly (4) during the capacitive sensing mode, and wherein the controller (5a, 5b) generates an acknowledgment signal when the first touch location is substantially equal to the second touch location.
    [3]
    The touch screen (1) according to any of the preceding claims, wherein the controller (Ba, 5b), during the resistive detection mode, applies unidirectional voltage drops to the upper electrode layer (6) of the resistive assembly (3) and / or on the lower electrode layer (7) of the resistive assembly (3).
    [4]
    The touch screen (1) according to the preceding claim, wherein the resistive assembly (3) is a four wire resistive assembly (3), the control device (5a) driving the resistive assembly (3) during the resistive detection mode, by alternately applying a unidirectional voltage drop to the upper electrode layer (6) of the resistive assembly (3) while detecting the lower electrode layer (7), and applying a perpendicular unidirectional voltage drop to the lower electrode layer (7) of the resistive assembly ( 3) while detecting the top electrode layer (6).
    [5]
    The touch screen (1) according to claim 3, wherein the resistive assembly (3) is a resistive assembly (3) with five wires, the controller (Ba) driving the resistive assembly (3) during the resistive detection mode, by alternating a applying a unidirectional voltage drop to a driven electrode layer comprising one of the top or the bottom electrode layer (6, 7) of the resistive assembly (3) while detecting the other electrode layer (6, 7) of the resistive assembly (3), and applying a perpendicular unidirectional voltage drop to the driven electrode layer while detecting the other electrode layer of the resistive assembly (3).
    [6]
    The touch screen (1) according to claim 3, wherein the resistive assembly (3) is a resistive assembly (3) with eight wires.
    [7]
    The touch screen (1) according to any of the preceding claims, wherein the capacitive assembly (4) comprises electrodes (8) that are physically distinct from the lower or upper electrode layer (6, 7) of the resistive assembly (3) ), and wherein the control device (5a) drives the resistive assembly (3) such that the resistive assembly (3) is used as a driven shield for the capacitive assembly (4) when the touch screen (1) is in capacitive detection mode, by driving the upper electrode layer (6) of the resistive assembly (3) such that the upper electrode layer (6) of the resistive assembly (3) is used as a driven shield for the capacitive assembly (4).
    [8]
    The touch screen (1) according to any one of the preceding claims, wherein the capacitive assembly (4) is a measuring assembly for measuring projected capacitance, the capacitive assembly (4) comprising X electrode strips extending in a first direction and Y electrode strips extending in a second direction, perpendicular to the first direction, to form an electrode grid (8).
    [9]
    The touch screen (1) according to any of the preceding claims, wherein the electrodes of the resistive assembly (3) and the capacitive assembly (4) are substantially transparent to visible light.
    [10]
    The touch screen (1) according to the preceding claim, wherein the electrodes of the resistive assembly (3) and the capacitive assembly (4) are made of an indium-tin oxide (ITO) alloy.
    [11]
    The touch screen (1) according to any of the preceding claims, wherein the touch screen (1) is arranged on top of a display.
    [12]
    A method of confirming a touch at a location on a touch screen (1), the method comprising the steps of e providing a touch screen (1) according to any of the preceding claims, e using the control device (Ba) driving the resistive assembly (3) to obtain a first touch location while the capacitive assembly (4) is kept in an inactive state, e driving the capacitive assembly (4) by means of the control device (5b) ) in order to obtain a second touch location while keeping the resistive assembly (3) in an inactive state and while simultaneously driving the resistive assembly (3) so that the resistive assembly (3) is used as a powered shield for the capacitive assembly ( 4) by applying a voltage V protection to the top and / or the bottom electrode layer (6, 7) of the resistive assembly (3), and wherein the voltage Vprotection is substantially equal to the voltage that the control device (5b) applies to the capacitive assembly (4) when the capacitive assembly (4) is driven, it by means of the control device (Ba, 5b) ) generating an acknowledgment signal when the first touch location is substantially equal to the second touch location.
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    同族专利:
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    BE1027408A9|2021-02-08|
    引用文献:
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    法律状态:
    2021-04-09| FG| Patent granted|Effective date: 20210202 |
    优先权:
    申请号 | 申请日 | 专利标题
    BE20195429A|BE1027408A9|2019-07-03|2019-07-03|IMPROVED TOUCH SCREEN FOR DETECTING THE LOCATION OF A TOUCH|BE20195429A| BE1027408A9|2019-07-03|2019-07-03|IMPROVED TOUCH SCREEN FOR DETECTING THE LOCATION OF A TOUCH|
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