WO2017031764A1

WO2017031764A1 - Apparatus and method for an rfid touch panel

Info

Publication number: WO2017031764A1
Application number: PCT/CN2015/088298
Authority: WO
Inventors: Zheng Shi
Original assignee: Zheng Shi
Priority date: 2015-08-27
Filing date: 2015-08-27
Publication date: 2017-03-02
Also published as: CN108292184A

Abstract

The present invention discloses an apparatus and method to combine the functionalities of radio frequency identification and capacitive sensing in a single interactive panel. The panel is capable of detecting an object with a low capacitive detection threshold, and a finger touch with a high capacitive detection threshold. Furthermore, the panel is capable of detecting multiple objects at the same time, well above the 11 independent touch points typically afforded by a touch screen of a smart phone or a smart tablet computer.

Description

APPARATUS AND METHOD FOR AN RFID TOUCH PANEL

TECHNICAL FIELD

The present invention relates to an interactive panel with both capacitive sensing and RFID tag reading capabilities.

BACKGROUND

The explosive growth of capacitive touch screens for smart phones and tablet computers have made touch screens a dominate form of human-computer interaction. These touch screens are typically designed and built for touch interactions between one user and a screen and, thus, only optimized to that effect.

Whenever one user is involved, there is little need for a function where more than 11 simultaneous finger touches are recognized by the smart phone or tablet screen. Nor is there much need for a function whereby multiple physical objects can interact with the touch screen. These types of applications are simply not of a concern for smart phones/tablet users.

US7928965 describes the combination of radio frequency identification technology with capacitive touch screen technology using the typical drive line and sense line structure.

According to one embodiment of US7928965, a single radio frequency loop antenna is formed on the same side of either the drive lines or the sense lines, with either the drive lines or the sense lines entirely enclosed within the loop antenna. In this design the loop antenna will have to be slightly larger than the entire area of the drive lines or sense lines. However, there is a limit as to how large the loop antenna can be implemented without introducing a center region incapable of radio frequency detection. Therefore, this design is impractical for a large panel (e.g., larger than a square of 20 cm by 20 cm) .

According to another embodiment of US7928965, a loop antenna is formed inside the drive lines. Unfortunately, such a design would disrupt the uniformity of the drive and sense lines, and thus, would negatively impact the effectiveness of the capacitive touch interactions by the user.

Although, using multiple loop antennas designed on a panel surface separate from the drive and sense lines would enable a large touch screen with uniformed radio frequency detection functionality, this design would still be limited in that it would not easily detect small conductive objects or be able to detect 11+ simultaneous touches.

Indeed, the biggest problem in using systems and methods similar to US7928965 is that, currently, there exist no commercially available computer chips that can derive more than 11 independent touches. Thus, the system and accompanying method described in US7928965 cannot be realistically implemented if one required an 11+ simultaneous touch recognition function. Furthermore, since there currently exist no commercially readily available chips that enable a capacitive touch screen to readily detect capacitive coupling from small conductive objects, US7928965 can neither be used if one required interaction between the touch screen and physical objects.

Therefore, a new type of interactive panel that can detect a much higher number of simultaneous touches than the current state of the art as well as allows for the detection and recognition of small conductive objects is desirable.

SUMMARY OF INVENTION

The present invention discloses an apparatus and method to combine the functionalities of radio frequency identification and capacitive sensing in a single interactive panel. The panel is capable of detecting an object with a low capacitive detection threshold, and a finger touch with a high capacitive detection threshold. Furthermore, the panel is capable of detecting many objects at the same time, well above the 11 independent touch points typically afforded by a touch screen of a smart phone or smart tablet computer. Such an apparatus could, for example, allow for a large number of letter-imprinted cards to generate real-time feedback whenever placed upon an interactive panel. This would become a useful language teaching tool for small children.

The apparatus of the present invention includes: an interactive panel that comprises one or more layers； an array of capacitive sensing electrodes on a first surface of a first layer, wherein each of the capacitive sensing electrodes is wired to sense a capacitive action independent from any other capacitive sensing electrodes； an array of RF loop antennas on a second surface of a second layer, wherein the detection range of each of the RF loop antennas spatially encompasses a subset of the capacitive sensing electrodes； an electrode processor that connects with each of the capacitive sensing electrodes, and an antenna processor that connects with each of the RF loop antenna.

The method of the present invention includes: forming an array of capacitive sensing electrodes on a first surface of a first layer of the interactive panel, wherein each of the capacitive sensing electrodes is wired to sense a capacitive action independent from any other capacitive sensing electrodes； forming an array of RF loop antennas on a second surface of a second layer of the interactive panel, wherein the detection range of each of the RF loop antennas spatially encompasses a subset of the capacitive sensing electrodes； connecting with, each of the capacitive sensing electrodes by an electrode processor, and each of the RF loop antenna by a antenna processor.

In one embodiment of the present invention the interactive panel is composed of a number of layers. The layers can be made of glass typical for a touch screen, or plastic typical for a printed circuit board.

In another embodiment of the present invention, the electrodes and their corresponding wires consist of transparent conductive material such as indium tin oxide placed upon a glass or glass-like layer.

In another embodiment of the present invention, the RF antennas consist of transparent conductive material such as indium tin oxide placed upon a glass or glass-like layer.

In another embodiment of the present invention, the first surface and the second surface are the top and bottom surfaces of the same layer.

In another embodiment of the present invention, the RF loop antennas are formed on the layer using a transparent conductive material.

In another embodiment of the present invention, the array of capacitive sensing electrodes is formed on the top surface of a glass layer, and the array of radio frequency loop antenna is formed on the bottom surface of same glass layer. The electrode circuitry and the antenna circuitry are formed using transparent conductive materials such as indium tin oxide within the electrode and antenna area, and by flexible printed circuitry to allow connection with a PCB wherein the processors reside. In this embodiment, chips and wires are cleanly separated from the transparent electrodes and antennas, to achieve uniformity and transparency of the interactive panel, and effective shielding of electromagnetic interference.

In another embodiment of the present invention, the apparatus further comprising of a computer unit that receives information from the electrode processor and the antenna processor, and uses such information as input for a computer program.

In another embodiment of the present invention, the capacitive action is a finger touch on the interactive panel at or near a capacitive sensing electrode.

In another embodiment of the present invention, an electronic display panel is added and controlled by the computer unit.

In another embodiment of the present invention, the capacitive action is a placement of an object on the interactive panel at or near a capacitive sensing electrode, and wherein the object comprises an element that is capable of being detected by the capacitive sensing electrode.

In another embodiment of the present invention, the element capable of being detected by the capacitive sensing electrode is an RFID tag embedded in the object.

In another embodiment of the present invention the computer unit is configured to set a threshold value for detecting the object that is lower than the threshold for detecting a finger touch.

BRIEF DESCRIPTION OF THE DRAWINGS

To better illustrate the technical features of the embodiments of the present invention, various embodiments of the present invention will be briefly described in conjunction with the accompanying drawings. It should be obvious that the drawings are but for exemplary embodiments of the present invention, and that a person of ordinary skill in the art may derive additional drawings without deviating from the principles of the present invention.

FIG. 1 is an exemplary schematic diagram of an interactive panel with multiple finger touch and object detection functions in accordance with one embodiment of the present invention.

FIG. 2 is an exemplary schematic diagram of the electrode array located on the first surface of the first layer in accordance with one embodiment of the present invention.

FIG. 3 is an exemplary schematic diagram of the RF loop antenna array located on the second surface of the second layer in accordance with one embodiment of the present invention.

FIG. 4 is an exemplary schematic cross-sectional diagram of the first and second layers superimposed on each other.

FIG. 5 is a flow chart of the method in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

To better illustrate the purpose, technical feature, and advantages of the embodiments of the present invention, various embodiments of the present invention will be further described in conjunction with the accompanying drawings.

While the present invention will be described in connection with various specific embodiments, the invention is not limited to these embodiments. People skilled in the art will recognize that the system and method of the present invention may be used in many other applications.

For example, the notion of “panel” or “interactive panel” is discussed for the sake of simplicity, but the present invention can easily be applicable in three dimensions.

In addition, while a specific capacitance sensor array and a specific antenna array design are disclosed in connection with embodiments of the present invention, other array designs can also be used and are within the scope of the present invention.

In addition, while a touch by a finger or object composed of or containing electrically conductive material upon the interactive panel is repeatedly used to represent an action that the electrode array detects, the use of other means, such as a stylus or a material with high dielectric constant are within the scope of the present invention.

Furthermore, while a specific communication flow between the processor, the RF antenna array, and multiple objects’ RFID chips, is disclosed in connection with embodiments of the present invention, the embodiments of the present invention is not limited to any particular process by which the UID of the object is detected by the interactive panel.

The present invention may be better understood and its objects and advantages will become more apparent to those skilled in the art by reference to the accompanying drawings.

FIG. 1 is an exemplary schematic diagram of an interactive panel with multiple finger touch and object detection functions in accordance with one embodiment of the present invention. An interactive panel 101 is provided whose surface can detect the location of multiple (i.e., more than 11) simultaneous finger touches 102 as well as physical objects 103 embedded with electrically capacitive material. The interactive panel 101 can further recognize the unique identification code (UID) of each physical object 103 placed upon its surface through wireless communication between the RF antenna (s) embedded in the interactive panel 101 and the RFID tag embedded within the physical objects 103.

FIG. 2 is an exemplary schematic diagram of the electrode array located on a first surface of a first layer in accordance with one embodiment of the present invention. The first layer 201 comprises of an array of electrodes 202 with each electrode 203 having its own independent electric wiring 204 connecting it to an electrode processor 205 and wherein each of the capacitive sensing electrodes 203 is independently wired to an electrode processor 205 in such a manner that each electrode 203 can sense a capacitive action independently from any other capacitive sensing electrodes 203. In the embodiment illustrated in FIG. 2, the electrode processors 205 are located at the periphery 206 of the interactive panel 201. Capacitive actions can be caused by either human finger touches upon one or more electrodes 203 or by placing of a physical object comprising or embedded with electrically capacitive material that is detectable by the electrodes 203. The electrodes 203 and accompanying electrode processors 205 are designed so that small changes of capacitance caused by objects having relatively small capacitive values can be detected.

Such a design is different from the conventional capacitive screen formed by drive lines and sense lines in that each of the electrodes 203 within the electrode array 202 can form an independent self-capacitance sensor, and any and all of the electrodes 203 within the electrode array 202 can be activated by one or more capacitive actions. In contrast, capacitive screens formed by drive lines and sense lines are designed to provide a maximum of 11 independent finger touches.

Although there is no real utility in having 10+ simultaneous finger touch detection in a smart phone or a smart tablet； however, in the case where a large interactive panel is interacted with by multiple users at the same time, resulting in dozens to even hundreds of independent touches (either through finger touches or via physical object manipulations such as card or building blocks) , the abovementioned function becomes desirable.

While it is currently unrealistic to expect the number of electrodes 203 to reach millions, since the electric wiring 204 of the each of the electrode 203 becomes too complex to be achieved and there are physical limitations in terms of spacing； however, an electrode array 202 with hundreds or a couple of thousand electrodes 203 are well within the state of art, with both the electrode 203 and its corresponding wires 204 implemented with either transparent conductive materials such as indium tin oxide on glass or glass-like material (for optimal uniformity and transparency of the capacitive touch screen) or through a non-transparent conductive material such copper on a plastic circuit board (i.e., PCB) .

FIG. 3 is an exemplary schematic diagram of the RF loop antenna array 302 located on the second surface of the second layer 301 in accordance with one embodiment of the present invention. The second surface of the second layer 301 has an array of RF loop antennas 302. The second layer 301 is superimposed upon the electrode array 202 of the first layer 201 and is designed in such a manner that the detection range of each of the RF loop antennas 303 spatially encompasses a subset of the capacitive sensing electrodes 203. The typical dimensions of a high-frequency radio frequency (RF) loop antenna are squares with side length of 5 cm to 15 cm depending on the density of the capacitive sensing electrodes 203. The physical layout of the loop antenna array 302 is experimentally chosen and verified to provide uniformed RFID tag detection functionality across the entire array 202 of the capacitive sensing electrodes 203.

As with the electrode array 202, all of the RF loop antennas 303 are under control of antenna processors 304. The electric wiring connecting the RF loop antennas 303 with their antenna processors 304 is designed to ensure that each RF loop antenna 303 is independently connected with an antenna processor 304.

As with the first layer 201, the antenna processors 304 are located at the periphery 305 of the second layer 301.

The RF loop antennas 303 and its corresponding wires are implemented with either transparent conductive materials such as indium tin oxide on glass or glass-like material (for optimal uniformity and transparency of the capacitive touch screen) or through a non-transparent conductive material such copper on a plastic circuit board (i.e., PCB) .

FIG. 4 is an exemplary schematic cross-sectional diagram of the first layer 201 and the second layer 301 superimposed on each other in accordance to one embodiment of the present invention.

The interactive panel 401 comprises of three layers superimposed on each other, with the first layer 201 comprising the electrodes 203 in the middle and the second layer 301 comprising the RF loop antennas 303 on the bottom. A protective sheet 403 is also affixed on top of the first layer 201. The first layer 201 and the second layer 301 are operationally connected to a computer unit 404. The computer unit 404 is configured to set a threshold value for detecting the object that is lower than the threshold for detecting a finger touch.

The process flow of the FIG. 4 is the following: a plurality of objects 402, each embedded with electrically capacitive material and an RFID tag containing the objects’ UID, are placed upon the interactive panel 401 causing the electrodes located under each object 402 to detect a change in capacitance and the electrode processors to further signal to the interactive panel’s computer unit 404 the exact location of each object 402. This triggers the computer unit 404 to command the RF antenna processors to have the RF antennas assigned to those electrodes 203 that have detected a change in capacitance to start wireless communication with the RFID chips of the detected objects 402 in order to obtain the UID of each detected object 402. In such a manner, the interactive panel 401 illustrated in FIG. 4 can locate and recognize the UID of a large number of objects (i.e., more than 11) as well as finger touches in real-time.

In another embodiment, the element capable of being detected by the capacitive sensing electrode 203 is the RFID tag embedded in the object 402 and the computer unit 404 is configured to set a low threshold value for detecting the object’s 402 RFID tag.

In another embodiment of the present invention, an electronic display panel is added as an additional superimposed layer of the first and second surfaces and controlled by the computer unit 404.

In another embodiment of the present invention, the array of capacitive sensing electrodes 202 is formed on the top surface of a glass layer, and the array of radio frequency loop antennas 302 is formed on the bottom surface of same glass layer. The electrode circuitry and the antenna circuitry are formed using transparent conductive materials such as indium tin oxide within the electrode and antenna area, and by flexible printed circuitry to allow connection with a PCB wherein the processors reside. In this embodiment, chips and wires are cleanly separated from the transparent electrodes and antennas and located in the periphery of the interactive panel so as to achieve uniformity and transparency of the interactive panel, and effective shielding of electromagnetic interference.

The method for providing both radio frequency identification (RFID) and capacitive sensing functionalities by an interactive panel, comprising forming an array of capacitive sensing electrodes on a first surface of a first layer of the interactive panel, wherein each of the capacitive sensing electrodes is wired to sense a capacitive action independent from any other capacitive sensing electrodes； forming an array of RF loop antennas on a second surface of a second layer of the interactive panel, wherein the detection range of each of the RF loop antennas spatially encompasses a subset of the capacitive sensing electrodes； connecting with, each of the capacitive sensing electrodes by an electrode processor, and each of the RF loop antenna by an RF loop antenna processor.

The method in accordance with one embodiment of the present invention can be described as follows forming an array of capacitive sensing electrodes on a first surface of a first layer of the interactive panel, wherein each of the capacitive sensing electrodes is wired to sense a capacitive action independent from any other capacitive sensing electrodes (501) ； forming an array of RF loop antennas on a second surface of a second layer of the interactive panel, wherein the detection range of each of the RF loop antennas spatially encompasses a subset of the capacitive sensing electrodes (502) ； connecting with, each of the capacitive sensing electrodes by an electrode processor, and each of the RF loop antennas by an RF loop antenna processor (503) ； connecting the electrode processor and antenna processor to a computer unit (504) .

Claims

An apparatus for providing radio frequency identification (RFID) and capacitive sensing capability, comprising:

-an interactive panel that comprises one or more layers,

-an array of capacitive sensing electrodes on a first surface of a first layer, wherein each of the capacitive sensing electrodes is wired to sense a capacitive action independent from any other capacitive sensing electrodes,

-an array of RF loop antennas on a second surface of a second layer, wherein the detection range of each of the RF loop antennas spatially encompasses a subset of the capacitive sensing electrodes,

-an electrode processor that connects with each of the capacitive sensing electrodes, and

-an antenna processor that connects with each of the RF loop antennas.
The apparatus of claim 1, further comprising a computer unit that receives information from the electrode processor and the antenna processor, and uses such information as input for a computer program.
The apparatus of claim 1, wherein the capacitive action is a finger touch on the interactive panel at or near a capacitive sensing electrode.
The apparatus of claim 1, wherein the capacitive action is a placement of an object on the interactive panel at or near a capacitive sensing electrode, and wherein the object comprises an element that is capable of being detected by the capacitive sensing electrode.
The apparatus of claim 4, wherein the element capable of being detected by the capacitive sensing electrode is an RFID tag embedded in the object.
The apparatus of claim 4, wherein the computer unit is configured to set a threshold value for detecting the object that is lower than the threshold for detecting a finger touch.
The apparatus of claim 2, further comprising an electronic display panel controlled by the computer unit.
The apparatus of claim 1, wherein the first surface and the second surface are the top and bottom surfaces of the same layer.
The apparatus of claim 1, wherein the RF loop antennas are formed on the layer using a transparent conductive material.
A method for providing both radio frequency identification (RFID) and capacitive sensing functionalities by an interactive panel, comprising:

-forming an array of capacitive sensing electrodes on a first surface of a first layer of the interactive panel, wherein each of the capacitive sensing electrodes is wired to sense a capacitive action independent from any other capacitive sensing electrodes,

-forming an array of RF loop antennas on a second surface of a second layer of the interactive panel, wherein the detection range of each of the RF loop antennas spatially encompasses a subset of the capacitive sensing electrodes,

-connecting with, each of the capacitive sensing electrodes by an electrode processor, and each of the RF loop antenna by an RF loop antenna processor.
The method of claim 10, further comprising a computer unit that receives information from the electrode processor and the antenna processor, and uses such information as input for a computer program.
The method of claim 10, wherein the capacitive action is a finger touch on the interactive panel at or near a capacitive sensing electrode.
The method of claim 10, wherein the capacitive action is a placement of an object on the interactive panel at or near a capacitive sensing electrode, and wherein the object comprises an element that is capable of being detected by the capacitive sensing electrode.
The method of claim 13, wherein the element capable of being detected by the capacitive sensing electrode is an RFID tag embedded in the object.
The method of claim 13, wherein the computer unit is configured to set a threshold value for detecting the object that is lower than the threshold for detecting a finger touch.
The method of claim 11, further comprising an electronic display panel controlled by the computer unit.
The method of claim 10, wherein the first surface and the second surface are the top and bottom surfaces of the same layer.
The method of claim 10, wherein the RF loop antennas are formed on the layer using a transparent conductive material.