WO2020246942A1

WO2020246942A1 - Interface device

Info

Publication number: WO2020246942A1
Application number: PCT/SG2020/050306
Authority: WO
Inventors: Qiongfeng SHI; Chengkuo Lee
Original assignee: National University of Singapore
Current assignee: National University of Singapore
Priority date: 2019-06-07
Filing date: 2020-05-26
Publication date: 2020-12-10
Anticipated expiration: 2021-12-07

Abstract

An interface device, a method of fabricating an interface device, and a method of generating action commands using the interface device. The method of fabricating an interface device comprises providing a substrate; forming an electrode array on the substrate; and forming a material layer over the substrate and electrode array, the material layer exhibiting a first electron affinity different from a second electron affinity of an object used to operate the interface device using a triboelectric effect; wherein forming the electrode array comprises arranging a plurality of electrodes, each electrode comprising a main portion laterally disposed between two finger portions, to define a substantially continuous pattern around a center point on the substrate by laterally overlapping respective finger portions of adjacent electrodes.

Description

INTERFACE DEVICE

FIELD OF INVENTION

The present invention relates broadly to an interface device, in particular to a multi-functional human machine interface (HMI) using a flexible wearable triboelectric patch, to a method of fabricating an interface device, and to a method of generating action commands using the interface device.

BACKGROUND

Any mention and/or discussion of prior art throughout the specification should not be considered, in any way, as an admission that this prior art is well known or forms part of common general knowledge in the field.

In recent years, flexible and wearable sensors have received extensive development and experienced flourishing prosperity across the world, making their ways toward diverse applications in amusement, healthcare, and human machine interface [1-4]. Among these applications, human machine interfaces together with wearable electronics are of more and more importance to link up human intentions with machine actions, ranging from daily operation of electronics to manipulation of exoskeletons for rehabilitation [5,6]. Nowadays, most of the reported flexible wearable sensors are developed based on the sensing mechanisms of resistive [7], capacitive [8], piezoelectric [9,10], triboelectric [11-13], or their hybrid mechanism [14-16]. Generally speaking, resistive and capacitive sensors require continuous power supply to achieve functional operation, which greatly increases the power consumption of the whole system. On the other hand, piezoelectric and triboelectric devices can produce self-generated electrical signals under ambient mechanical stimulus based on the piezoelectric or triboelectric effect of the materials. Since the first invention in 2012 by Prof. Z. L. Wang and his team [17], triboelectric nanogenerator (TENG) has become one of the most popular self-powered solutions for the aforementioned applications, due to its superior advantages including diverse configurations, easy manufacturing, high performance, no material limitation and low cost [18-22]. TENG has received tremendous research interests and efforts internationally for a wide range of applications, with several developing trends clearly observed from the TENG technology roadmap, e.g., water wave energy harvesting toward the blue energy dream [23-27], medical/ implanted healthcare monitoring and treatment [28-30], the new era of internet of things (IoT) [31-34], advanced human machine interfaces [35-40], etc.

The integration of human machine interfaces with TENG technology enables the realization of flexible wearable and self-powered interfaces, remarkably broadening the usage adaptation and enhancing the interacting experience. Lately, various triboelectric interfaces have been developed for the applications in different areas, e.g., tactile sensor array based interfaces [41- 43], novel coding interfaces [44-46], and robotic finger sensors and/or finger motion sensors [47-49], etc. In terms of human interactions upon different interfaces, tapping and sliding are two of the most commonly used operations, such as using smartphones, touch screens, writing pads, etc. In order to detect the tapping positions and sliding traces, one of the most common approaches is through multiple sensing elements forming integrated array configuration, either with separated sensing pixels and separated electrodes for each pixel [50-52], or with intersecting column and row electrodes for the entire column/row [42,53-55]. For instance, an array of 9x9 intersecting electrodes is presented for the detection of contacting position, moving trajectory and velocity when an active object is sliding on the surface [53]. Another electronic skin based interface with 5x5 electrodes is reported to monitor the planar displacement of an object above the device surface, as long as the object is pre-charged with triboelectric charges [54]. However, one main problem of the array configurations is the large number of sensing electrodes, which significantly increases the complexity in layout design, device manufacture, signal acquisition and processing.

In order to reduce the number of electrodes, devices based on the concept of analogue skin have recently been developed, with four electrodes located at the four edges of the sensing area [56-58]. The contact position of an object can be recognized according to the voltage ratios of the two pairs of opposite electrodes. One drawback of this configuration is the small output performance due to the indirect coupling of triboelectric charges on the electrodes, and the associated high susceptibility to ambient noises. Moreover, only the position of each tapping can be detected using this configuration but not the sliding traces. More recently, integration of grid pattern with certain thickness on the analogue skin surface was proposed to achieve the detection of sliding traces [59, 60]. The function of the grid pattern is to transform the continuous sliding motion into intermittent tapping motions along the sliding trace. Although such design can achieve the detection of sliding, the integration of a thick grid pattern on a surface introduces extra constraints to the device, largely degrading its flexibility, applicability and interacting experience. In addition, it should be noted that the small output performance and the high noise susceptibility are still not fully addressed in that design. Therefore, development of an advanced triboelectric interface with good performance is highly desirable, in order to achieve detection of both tapping and sliding interactions.

Embodiments of the present invention seek to address at least one of the above problems.

SUMMARY

In accordance with a first aspect of the present invention, there is provided an interface device comprising:

a substrate;

an electrode array formed on the substrate; and a material layer formed over the substrate and electrode array, wherein the material layer exhibits a first electron affinity different from a second electron affinity of an object used to operate the interface device using a triboelectric effect;

wherein the electrode array comprises a plurality of electrodes arranged to define a substantially continuous pattern around a center point on the substrate; and

wherein each electrode comprises a main portion laterally disposed between two finger portions, and respective finger portions of adjacent electrodes laterally overlap for forming the substantially continuous pattern.

In accordance with a second aspect of the present invention, there is provided a method of fabricating an interface device comprising:

providing a substrate;

forming an electrode array on the substrate; and

forming a material layer over the substrate and electrode array, the material layer exhibiting a first electron affinity different from a second electron affinity of an object used to operate the interface device using a triboelectric effect;

wherein forming the electrode array comprises arranging a plurality of electrodes, each electrode comprising a main portion laterally disposed between two finger portions, to define a substantially continuous pattern around a center point on the substrate by laterally overlapping respective finger portions of adjacent electrodes.

In accordance with a third aspect of the present invention, there is provided method of generating action commands using the interface device of the first aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be better understood and readily apparent to one of ordinary skill in the art from the following written description, by way of example only, and in conjunction with the drawings, in which:

Fig. 1 (a) shows a schematic diagram of the device according to an example embodiment attached on human arm for various human machine interacting applications.

Fig. 1 (b) shows a digital photograph showing the flexible device according to an example embodiment can be attached conformally on an arm.

Fig. 1 (c) shows a 3D schematic diagram showing the structure of a device according to an example embodiment with three thin layers. Fig. 1 (d) shows the electrode layout and eight predefined electrode points on a device according to an example embodiment.

Fig. 1 (e) shows a digital photograph of a device according to an example embodiment on a flat surface.

Fig. 1 (f) shows schematic drawings illustrating the working principle of a device according to an example embodiment when operating on the individual electrode points (Point 1, 3, 5 and

7).

Fig. 1 (g) shows schematic drawings illustrating the working principle of a device according to an example embodiment when operating on the common electrode points (Point 2, 4, 6 and 8). Fig. 2. (a) shows a schematic diagram illustrating three points on a device according to an example embodiment under tapping.

Fig. 2 (b) shows the voltage ratio of VI and V2 of the three points on a device according to an example embodiment with different tapping forces (FI -0.6 N, F2 -3 N, and F3 -10 N).

Fig. 2 (c) shows the voltage ratio of VI and V2 of the three points on a device according to an example embodiment with different tapping frequencies (fl -0.75 Hz, f2 -1.25 Hz, and f3 -1.75 Hz).

Fig. 2 (d) shows the output voltages from El and E2 when tapping on Point 1 on a device according to an example embodiment with different forces.

Fig. 2 (e) shows the output voltages from El and E2 when tapping on Point 2 on a device according to an example embodiment with different forces.

Fig. 2 (f) shows the output voltages from El and E2 when tapping on Point 3 on a device according to an example embodiment with different forces.

Fig. 2 (g) shows the output voltages from El and E2 when tapping on Point 1 on a device according to an example embodiment with different frequencies.

Fig. 2 (h) shows the output voltages from El and E2 when tapping on Point 2 on a device according to an example embodiment with different frequencies.

Fig. 2 (i) shows the output voltages from El and E2 when tapping on Point 3 on a device according to an example embodiment with different frequencies.

Fig. 3 (a) shows a Schematic diagram showing the three points on a device according to an example embodiment under sliding.

Fig. 3 (b) shows the voltage ratio of VI and V2 of the three points on a device according to an example embodiment with different sliding forces (Fl -0.6 N, F2 -3 N, and F3 -10 N). Fig. 3 (c) shows the voltage ratio of VI and V2 (V1/V2) of the three points on a device according to an example embodiment with different sliding frequencies (fl -0.75 Hz, f2 -1.25 Hz, and f3 -1.75 Hz).

Fig. 3 (d) shows the output voltages from El and E2 when repeatedly sliding on Point 1 on a device according to an example embodiment with different forces.

Fig. 3 (e) shows the output voltages from El and E2 when repeatedly sliding on Point 2 on a device according to an example embodiment with different forces.

Fig. 3 (f) shows the output voltages from El and E2 when repeatedly sliding on Point 3 on a device according to an example embodiment with different forces.

Fig. 3 (g) shows the output voltages from El and E2 when repeatedly sliding on Point 1 on a device according to an example embodiment with different frequencies.

Fig. 3 (h) shows the output voltages from El and E2 when repeatedly sliding on Point 2 on a device according to an example embodiment with different frequencies.

Fig. 3 (i) shows the output voltages from El and E2 when repeatedly sliding on Point 3 on a device according to an example embodiment with different frequencies.

Fig. 4 (a) shows a schematic diagram of the eight electrode points on a device according to an example embodiment under tapping.

Fig. 4 (b) shows the output voltages from all the four electrodes when tapping on the eight points on a device according to an example embodiment.

Fig. 4 (c) shows the output voltage ratios of V1/V2, V1/V3, and V1/V4 corresponding to Fig, 4 (b).

Fig. 4 (d) shows a schematic diagram of the eight electrode points on a device according to an example embodiment under sliding.

Fig. 4 (e) shows the output voltages from all the four electrodes on a device according to an example embodiment when sliding on the eight points.

Fig. 4 (f) shows the output voltage ratios of V1/V2, V1/V3, and V1/V4 corresponding to Fig. 4 (e).

Fig. 5 (a) shows a schematic diagram of the operations (tapping + sliding + leaving) between Point M and Point 5, and Point M and Point 6, on a device according to an example embodiment.

Fig. 5 (b) shows the output voltages from the operations (tapping + sliding + leaving) between Point M and Point 5 on a device according to an example embodiment. Fig. 5 (c) shows the output voltages from the operations (tapping + sliding + leaving) between Point M and Point 6 on a device according to an example embodiment.

Fig. 5 (d) shows a schematic diagram of the operations (tapping + sliding + leaving) between Point M and Point A5, and Point M and Point A6, on a device according to an example embodiment.

Fig. 5 (e) shows the output voltages from the operations (tapping + sliding + leaving) between Point M and Point A5 on a device according to an example embodiment.

Fig. 5 (f) shows the output voltages from the operations (tapping + sliding + leaving) between Point M and Point A6 on a device according to an example embodiment.

Fig. 5 (g) shows a schematic diagram of the operations (tapping + sliding + leaving) between Point 5 and Point A5, and Point 6 and Point A6, on a device according to an example embodiment.

Fig. 5 (h) shows the output voltages from the operations (tapping + sliding + leaving) between Point 5 and Point A5 on a device according to an example embodiment.

Fig. 5 (i) shows the output voltages from the operations (tapping + sliding + leaving) between Point 6 and Point A6 on a device according to an example embodiment.

Fig. 6 (a) shows a schematic diagram of the operations (tapping + sliding + leaving) between Point A7 and Point A3, and Point A6 and Point A2, on a device according to an example embodiment.

Fig. 6 (b) shows the output voltages from the operations (tapping + sliding + leaving) between Point A7 and Point A3on a device according to an example embodiment.

Fig. 6 (c) shows the output voltages from the operations (tapping + sliding + leaving) between Point A6 and Point on a device according to an example embodiment.

Fig. 6 (d) shows a schematic diagram of the operations (tapping + sliding + leaving) between Point A7 and Point 3, and Point A6 and Point 2, on a device according to an example embodiment.

Fig. 6 (e) shows the output voltages from the operations (tapping + sliding + leaving) between Point A7 and Point 3 on a device according to an example embodiment.

Fig. 6 (f) shows the output voltages from the operations (tapping + sliding + leaving) between Point A6 and Point 2 on a device according to an example embodiment.

Fig. 6 (g) shows a schematic diagram of the operations (tapping + sliding + leaving) between Point 7 and Point 3, and Point 6 and Point 2, on a device according to an example embodiment.

Fig. 6 (h) shows the output voltages from the operations (tapping + sliding + leaving) between Point 7 and Point 3 on a device according to an example embodiment. Fig. 6 (i) shows the output voltages from the operations (tapping + sliding + leaving) between Point 6 and Point 2 on a device according to an example embodiment.

Fig. 7 (a) shows a schematic diagram of the operations (tapping + sliding + leaving) between Point 2 and Point 8 on a device according to an example embodiment.

Fig. 7 (b) shows the output voltages from the operations (tapping + sliding + leaving) between Point 2 and Point 8 on a device according to an example embodiment.

Fig. 7 (c) shows a schematic diagram of the operations (tapping + sliding + leaving) between Point 1 and Point 7 on a device according to an example embodiment.

Fig. 7 (d) shows the output voltages from the operations (tapping + sliding + leaving) between Point 1 and Point 7 on a device according to an example embodiment.

Fig. 7 (e) shows a schematic diagram of the circling around all the electrode points starting from Point 1 on a device according to an example embodiment.

Fig. 7 (f) shows the output voltages from the circling around all the electrode points starting from Point 1 on a device according to an example embodiment.

Fig. 7 (g) shows a schematic diagram of the circling around all the electrode points starting from Point 2 on a device according to an example embodiment.

Fig. 7 (h) shows the output voltages from the circling around all the electrode points starting from Point 2 on a device according to an example embodiment.

Fig. 8 (a) shows the demonstration using the device according to an example embodiment as a writing interface, including the operation procedures on the device, corresponding output voltages and the writing traces on a display screen when writing the character of“N”.

Fig. 8 (b) shows the demonstration using the device according to an example embodiment as a writing interface, including the operation procedures on the device, corresponding output voltages and the writing traces on a display screen when writing the character of“U”.

Fig. 8 (c) shows the demonstration using the device according to an example embodiment as a writing interface, including the operation procedures on the device, corresponding output voltages and the writing traces on a display screen when writing the character of“S”.

Fig. 9 (a) shows schematic diagrams illustrating using the device according to an example embodiment as an identification code system with coding definition of sixteen sections.

Fig. 9 (b) shows the output voltage waveforms when the finger slides on the sixteen sections of Fig, 9 (a) for a decimal code system.

Fig. 9 (c) shows the output voltage waveforms when the finger slides on the sixteen sections of Fig, 9 (a) for a 4-digit binary code system. Fig. 9 (d) shows a schematic drawing illustrating a conceptual scenario of autonomous express delivery where an identification code is required to open the box for retrieving goods, according to an example embodiment.

Fig. 9 (e) shows the output voltage waveforms of an identification code of“96632748” for use in the scenario of Fig, 9 (d).

Fig. 10 (a) shows a block diagram of a control interface system for wireless vehicle manipulation according to an example embodiment.

Fig. 10 (b) shows schematic diagram of the operations, the corresponding output voltages and an illustration of the movements of the vehicle when controlling the vehicle to go forward, according to an example embodiment.

Fig. 10 (c) shows schematic diagram of the operations, the corresponding output voltages and an illustration of the movements of the vehicle when controlling the vehicle to go backward, according to an example embodiment.

Fig. 10 (d) shows schematic diagram of the operations, the corresponding output voltages and an illustration of the movements of the vehicle when controlling the vehicle to turn left, according to an example embodiment.

Fig. 10 (e) shows schematic diagram of the operations, the corresponding output voltages and an illustration of the movements of the vehicle when controlling the vehicle to turn right, according to an example embodiment.

Fig. 10 (f) shows schematic diagram of the operations, the corresponding output voltages and an illustration of the movements of the vehicle when controlling the vehicle to go left front, according to an example embodiment.

Fig. 10 (g) shows schematic diagram of the operations, the corresponding output voltages and an illustration of the movements of the vehicle when controlling the vehicle to go right front, according to an example embodiment.

Fig. 10 (h) shows schematic diagram of the operations, the corresponding output voltages and an illustration of the movements of the vehicle when controlling the vehicle to go left rear, according to an example embodiment.

Fig. 10 (i) shows schematic diagram of the operations, the corresponding output voltages and an illustration of the movements of the vehicle when controlling the vehicle to go right rear, according to an example embodiment.

Figure 11 shows a flow-chart illustrating a method of fabricating an interface device according to an example embodiment. DETAILED DESCRIPTION

Embodiments of the present invention provide a flexible triboelectric interacting patch with only four sensing electrodes to detect various human machine interactions. The four electrodes are configured in the layout of a splitting ring according to example embodiments. Initially, by leveraging the individual areas and common jointing areas of the four electrodes, eight functional electrodes points are defined, which can achieve position sensing with clear differentiations even under different types of operations including both tapping and sliding interactions, according to example embodiments. Moreover, nine additional points out of the electrode areas can be defined as well for more advanced sensing of operation positions and manners according to further example embodiments, through distinguishing the unique patterns of the generated voltage. With these predefined points, the interacting patch can be applied as general interface for various human machine interactions according to example embodiments. Based on the fabricated device, functional interfaces for writing trace recognition, identification code system and remote control are successfully realized, by way of example only, showing the high applicability of the device in diversified human machine interactions. Indicated by these affluent demonstrations, the interacting patch according to example embodiments exhibits great potential in various interacting applications, e.g., writing pad, security, smart control, entertainment, virtual reality, augmented reality, and robotics, etc.

Design configuration and working mechanism according to example embodiments

As illustrated in Fig. 1(a) and (b), the interacting patch 100 according to an example embodiment can be conformally attached on human arm 102, showing great potential as flexible wearable and self-powered interface in various human machine interacting applications. The detailed structure of the device 100 is shown in Fig. 1(c), an comprises three stacking thin layers, i.e., polyethylene terephthalate (PET) substrate 104, patterned aluminum (Al) electrode layer 106 and polytetrafluoroethylene (PTFE) friction layer 108. There are four sensing electrodes (labelled as El, E2, E3 and E4 accordingly), with the layout forming what is referred to herein as a splitting ring structure or split ring electrode. The middle main portion of each electrode, labelled as points 1, 3, 5, and 7 in circles in Fig. 1(d), forms the individual area, while the extrusion portions, labelled as points 2, 4, 6, and 8 in circles in Fig. 1(d), of two adjacent electrodes form the common jointing area. Thus there are four individual areas and four common areas around the electrode patterns, which are defined as individual electrode points and common electrode points. The digital photograph of the patch 100 on a flat surface is shown in Fig. 1(e), where the scale bar is 5 cm.

The working mechanism of the patch 100 with tapping or sliding operation on individual electrode points (Point 1, 3, 5 or 7) is illustrated using the schematics in Fig. 1(f). Initially, all the four electrodes are connected in single-electrode triboelectric mode with resistor loads e.g. 110. Due to the different electron affinity of PTFE and a person’s finger (bare finger or finger with e.g. nitrile glove), the finger 112 surface becomes positively charged while the PTFE layer 108 surface becomes negatively charged after contacting with each other. The pre charging of the surfaces, typically a few times of tapping the finger 112 onto the PTFE layer 108, prior to starting the operation described hereinafter has been omitted from the figures. In the original state, the finger 112 is staying away from the patch surface. Then when the finger 112 is approaching and finally contacts the individual electrode area, electrons are driven to flow from ground to the respective electrode due to the arisen electric potential difference. Thus current flow h is induced in the external circuit of that electrode, while no current flows are induced for the other three electrodes. Next, when finger 112 leaves the patch surface and goes back to the original position, electrons are driven to flow back to the ground, inducing an opposite current flow only on that electrode as well.

In terms of the sliding operation on the individual electrode point, the working mechanism is similar to the tapping operation. When the finger 112 is sliding on the individual electrode point from other position (e.g., middle portion or outer portion of the device), current flow is induced on the respective electrode. Then when the finger is sliding out of the individual electrode point, another current flow with opposite direction is generated. On the other hand, the working mechanism with tapping or sliding operation on common electrode points (Point 2, 4, 6 or 8) is illustrated with the schematics shown in Fig. 1(g). When the finger 112 is tapping (or sliding) on the common electrode point, the contacting area of the finger can cover the extrusion portions of both electrodes, indicted as electrode portions 114 and 116 in Fig. 1(g). Thus the arisen electric potential difference induces current flows h and h on both of the two adjacent electrodes, respectively. Later, when the finger 112 is leaving (or sliding out of) the common electrode area, current flows h and h in the opposite direction are generated on both electrodes as well.

As described above, for tapping and sliding operations on individual electrode points 1, 3, 5, and 7, output signal is only generated on the operated electrode, while for the operations on common electrode points 2, 4, 6, and 8, output signals are generated on both of the two adjacent electrodes.

Characteristics with tapping and sliding interactions according to example embodiments

According to the working mechanism of the interacting patch according to an example embodiment as described above, when operating on individual electrode points, output signal is only generated on the corresponding electrode. When operating on common electrode points, output signals are then generated on both of the operated electrodes. For conventional triboelectric devices, their output performance is highly susceptible to the environmental and operational parameters, such as contact force, frequency, etc. One possible solution is using the voltage ratios of two or more sensing electrodes to achieve robust and reliable signal detection. The approach of voltage ratios is also adopted for the recognition of different operations on a device according to an example embodiment.

First, the output characteristics of the device 200 according to an example embodiment are investigated with tapping operations of different contact forces and frequencies. As illustrated in Fig. 2(a), tapping operations on Points 1, 2 and 3 are conducted and the output signals from El and E2 are measured. Figs. 2(d) to (f) show the output signals from Points 1, 2 and 3, respectively, with three different tapping forces (FI -0.6 N, F2 -3 N, and F3 -10 N). The output voltage ratio of VI and V2 (i.e., V 1/V2) is plotted in Fig. 2(b) for the operations of these three points. As can be seen, in terms of the same operated point, the absolute magnitude of output voltages increases with tapping forces, but the voltage ratio is almost not affected by tapping forces. As for different points, the output voltage ratio clearly shows a noticeable variation, with the values in the range of >10, ~1 and <0.1, indicating that the voltage ratio can be used as a reliable approach for tapping position detection, i.e. irrespective of tapping force. Similarly, Figs. 2(g) to (i) show the output signals from Point 1, 2 and 3 with three different tapping frequencies (fl -0.75 Hz, f2 -1.25 Hz, and f3 -1.75 Hz). The corresponding output voltage ratio V 1/V2 is plotted and compared in Fig. 2(c). It can also be observed that the output voltage magnitude increases with frequencies while the voltage ratio is almost not affected for the same point. The voltage ratios for different points exhibit clear difference as well, falling into the same range of >10, -1 and <0.1.

Therefore, as can be seen from Figs. 2(a) to (i), for the tapping operations on the electrode points, the voltage ratio offers a general detection approach of different operated positions, which is highly robust against tapping force, frequency, etc.

Next, the output characteristics with different sliding operations are investigated for the device 200 according to an example embodiment. Fig. 3(a) illustrates the sliding operations on three electrode points (Point 1, 2 and 3), where the sliding operation starts from the middle portion of the device 200 and across each of the three points. The output voltages when sliding on the three points are shown in Figs. 3(d) to (f), respectively, with three different sliding forces (Fl -0.6 N, F2 -3 N, and F3 -10 N). The calculated voltage ratio V1/V2 is plotted in Fig. 3(b). It can be seen that for the same point, the magnitude of output voltages increases with sliding forces while the voltage ratio is of similar level. In terms of different points, the voltage ratios have clearly differentiated values, in the range of >10, -1 and <0.1 for the three points. Then the output voltages from Point 1, 2 and 3 with three different sliding frequencies (fl -0.75 Hz, f2 -1.25 Hz, and f3 -1.75 Hz) are shown in Figs. 3(g) to (i), respectively. The resulted voltage ratio V1/V2 is plotted in Fig. 3(c). It can also be seen that although the voltage magnitude increases with sliding frequencies, the voltage ratio is almost not affected by frequencies and follows the same trend for different points, i.e., in the range of >10, -1 and <0.1.

Therefore, as can be seen from Figs. 2(a) to (i) and Figs. 3(a) to (i), whether it is tapping operation or sliding operation, the voltage ratio of different electrodes offers high robustness against operation force and frequency, indicating high applicability of devices according to example embodiments for detection of operated positions even with different interacting manners.

The characterizations of all the eight electrode points are carried out in terms of both tapping and sliding operations. Fig. 4(a) depicts the tapping positions on the eight electrode points of the device 200 according to an example embodiment. The generated output voltages from the four electrodes are shown in Fig. 4(b), with tapping operations performed from Point 1 to Point 8 consecutively. Then the voltage ratios of VI against the other voltages, i.e., V1/V2, V1/V3 and V1/V4, are calculated and compared in Fig. 4(c) for each successive tapping action from Point 1 to Point 8. The results indicate that output voltage is generated on a certain electrode only when it is tapped by the finger (either the individual area or the common jointing area). Otherwise, voltage with negligible magnitude is induced on that electrode, i.e. if none of the individual area or the common jointing areas are tapped. Accordingly, the resulted values of V1/V2, V1/V3 and V1/V4 can also be categorized into the same ranges as the previous measurements (> 10, < 0.1 and ~ 1), indicating the consistency, robustness and generality of the voltage ratio based detection mechanism according to example embodiments.

More specifically, in the case of Point 1 under tapping, since output voltage is only generated on El, all the values of V1/V2, V1/V3 and V1/V4 are larger than 10. When Point 2 is under tapping, output voltages are then generated on both El and E2, leading to V1/V2 around 1 while V1/V3 and V1/V4 remain larger than 10. Then for Point 3, output voltage is only generated on E2, and thus V1/V2 is less than 0.1 while V1/V3 and V1/V4 are around 1. For Point 4, output voltages are only generated on E2 and E3, and thereby V1/V2 and V1/V3 are both less than 0.1 while V1/V4 is around 1. In the case of Point 5, output voltage is only generated on E3, and thus V1/V2, V1/V3 and V1/V4 are ~1, <0.1 and ~1, respectively. Then for Point 6, output voltages are generated on E3 and E4, leading to V 1/V2 around 1 while both V1/V3 and V1/V4 less than 0.1. Next, for Point 7, output voltage is only generated on E4, and thus both V1/V2 and V1/V3 are around 1 while V1/V4 is less than 0.1. Similarly, for Point 8, output voltages are generated on both E4 and El, and thereby V 1/V2 and V 1/V3 are larger than 10 while V1/V4 is around 1.

If sliding operations are performed on the eight points, a similar trend of output characteristics can be observed, as shown in Figs. 4(d) to (f). Although the absolute magnitude of output voltages may change, the voltage ratios still remain consistent at the same ranges. Therefore, using voltage ratios as a general detecting mechanism, operated positions of different electrode points can be clearly distinguished under different interacting manners according to example embodiment, offering excellent robustness and reliability in various human interactions.

Benefited from the advanced electrode layout, the device 200 according to an example embodiment can detect not only the eight electrode points 1 to 8 defined on the electrode areas, but also additional points outside the electrode areas. As illustrated in Fig. 5(a), nine additional points outside the electrode areas are defined according to an example embodiment, i.e., middle point (M) and eight outer points (A1-A8) on the outer side of the split ring electrode. Human interactions on the device 200 can be analogous to the operations of a touch screen smart phone, which normally include the following procedures: finger contacting the device surface, sliding on the surface, ending the sliding, and leaving the device surface. Tapping can be considered as a special case with sliding distance of 0.

First, operations between Point M and the electrode points (Point 5 and 6 as examples, illustrated in Fig, 5(a)) are investigated, together with the corresponding signal waveforms shown in Fig. 5(b) and (c). When the finger first contacts point M, positive voltage peaks with small magnitude are generated on all the four electrodes due to the coupling of a small amount of triboelectric charges on each electrode. When the finger slides from M onto electrode point 5, a large positive peak is generated on E3 due to the direct coupling of a large amount of triboelectric charges with E3 only. When the finger slides from M onto electrode point 6, one large positive peak is generated on each of E3 and E4, due to the direct coupling of large amount of triboelectric charges with both E3 and E4.

If the finger stops sliding and stays on the electrode point 5 or 6, no output peak is generated for that period. The moment when the finger leaves the device 200 from electrode point 5, a large negative peak is generated on E3. When the finger leaves the device 200 from electrode point 6, one large negative peak is generated on each of E3 and E4. For the sliding operation in the opposite direction (i.e., from the electrode points e.g. 5, 6 to point M), output voltage peaks with similar magnitude but opposite polarity are generated in a reverse manner.

Therefore, according to the triboelectric working mechanism of example embodiments, when the finger contacts a point outside the split electrode area, only a small output peak will be generated because triboelectric charges cannot be effectively coupled to the split electrode with the relatively large distance. When the finger directly contacts/taps or slides on an electrode point on the split electrode area, a large output peak will be then generated due to effective coupling of large amount of charges on the split electrode. That is to say, output peaks generated from electrode points 1 to 8 are larger than those from additional points M, A1 to A8. In addition, output peaks generated from contacting and leaving an electrode point are normally larger than those generated from sliding on and out of an electrode point, since the operation period of touching/leaving is shorter than sliding.

As shown in Fig. 5(d) to (f), investigation of the output characteristics induced by operations between point M and outer points (outer points A5 and A6 as examples, via electrode points 5 and 6 as examples) were also conducted. In this case, when the finger first contacts point M, small positive peaks are also generated on all the four electrodes. Then when the finger slides across electrode point 5 (or electrode point 6), successive positive and negative peaks are generated on E3 (or on each of E3 and E4). When the finger continuous to slide and stops on the outer point A5 (or A6), no output peak is generated. Then when the finger leaves the device 200 from point A5 (or Point A6), a small negative peak is generated on E3 (or on each of E3 and E4) according to the layout of the electrodes. Similarly, output peaks with opposite polarity in a reverse order are generated from the opposite operation.

Fig. 5(g) to (i) show the output characteristics from the operations between electrode points and outer points. When the finger first contacts the device 200 from electrode point 5 (or electrode point 6), a large positive peak is generated on E3 (or on each of E3 and E4). Then when the finger slides out of the split electrode area, negative peaks are generated on the corresponding electrodes. It is worth to note that for E4 as in Fig. 5(i), positive peak is first generated before the negative peak under this operation. This is because when the finger slides from Point 6 toward outside, the covering area of E4 by finger is actually increasing first before decreasing. Next, when the finger continues to slide and stop on the outer point A5 (or A6), no output peak is generated during this period. The moment when the finger leaves the device 200 from outer point A5 (or A6), a small negative peak is generated on E3 (or on each of E3 and E4). Similar output peaks with opposite polarity and reverse order are generated for the opposite direction.

Other operations of the device 200 according to an example embodiment have also been performed and investigated. For example, operations between outer points A7 and A3 (or between points A6 and A2) and the corresponding output signals are illustrated in Figs. 6(a) to (c). First, when the finger contacts outer point A7 (or A6), a small positive peak is generated on E4 (or on each of E3 and E4). Then when the finger slides across electrode point 7 (or electrode point 6), successive positive and negative peaks are generated on E3 (or on each of E3 and E4). Next, when the finger slides across electrode point 3 (or electrode point 2), successive positive and negative peaks are generated on E2 (or on each of El and E2). Lastly, when the finger leaves the device 200 from outer point A3 (or A2), a small negative peak is generated on E2 (or on each of El and E2). For the operation in opposite direction, output peaks with opposite polarity and reverse order are generated accordingly.

Similarly, as shown in Fig. 6(d) to (i), different output patterns can also be detected by the device 200 according to an example embodiment with the operations between an outer point and an electrode point (across another electrode point) or between two electrode points, and then can be used to differentiate different operations. Generally, large output peaks are generated when the finger operates on (e.g., contacts, leaves, slides on or slides out of) an electrode point, and small output peaks are generated when the finger operates on other points. In terms of polarity, positive peaks are generated when the finger contacts the device or slides on an electrode point, and then negative peaks are generated when finger leaves the device 200 or slides out of an electrode point.

In addition to the operations in straight lines, operations circling partially or fully around the electrode points (involving multiple electrode points) were investigated as well. As illustrated in Fig. 7(a) and (b), when the finger first contacts the device 200 according to an example embodiment on electrode point 2, large positive peaks are generated on each of El and E2. When the finger slides to from electrode point 2 to electrode point 1, a small positive peak is generated from El and a small negative peak is generated from E2, due to the increment of contact area for El and the decrement of contact area for E2. Next, when the finger slides to electrode point 8, a small negative peak is generated from El and a small positive peak is generated from E4. Lastly, when the finger leaves the device 200 from Point 8, a large negative peak is generated on each of El and E4.

For the operation illustrated in Fig. 7(c) and (d), a large positive peak is first generated on El for contacting electrode point 1. Then a small negative peak is generated from El and a small positive peak is generated from E4 for sliding to electrode point 8. Next, a small negative peak is generated from El and a small positive peak is generated from E4 for sliding to electrode point 7. Lastly, a large negative peak is generated on E4 for leaving the device from electrode point 7. In terms of a full circling operation starting from electrode points 1, 3, 5, or 7, e.g. electrode point 1 as shown in Fig. 7(e) and (f), a large positive peak and a large negative are always generated for contacting and leaving the respective electrode points. For the circling operation across each of electrodes El to E4, e.g. for El across electrode points 2, 1, and 8, two small positive peaks are first generated for sliding onto the electrode, e.g. from electrode point 3 to electrode point 2 and then onto electrode point 1, and then two small negative peaks are generated for sliding out of that electrode, e.g. from electrode point 1 to electrode point 8 and then onto electrode point 7. Similarly, for circling operation starting from electrode points 2, 4, 6, or 9, e.g. from electrode point 2 as indicated in Fig. 7(g) and (h), except for that the signals generated from first touching and last leaving operations are on two electrodes, e.g. from El and E2 for starting from and leaving electrode point 2, rather than one. Based on the above characteristics, the device 200 according to an example embodiment is able to recognize various human interactions, including tapping, sliding, tapping + sliding, etc. This outstanding detection capability of the device 200 indicates the capability of embodiments of the present invention of being adopted in a wide range of advanced sensing and control applications.

Writing pad interface according to example embodiments

Generally, writing is difficult to be detected by the non-pixel interfaces due to the inclusion of both tapping and sliding operations. Benefited from the excellent detection capability, devices according to example embodiments of the present invention are able to perform writing recognition with only four electrodes. Fig. 8 shows the writing operations on the device 200 according to an example embodiment and the constructed traces of a character according to the detected positions of the finger. For instance, to write the character“N” as indicated in Fig. 8(a), the finger first contacts electrode point 8, which can be detected through the positive output peak on each of El and E4. Then the corresponding point is highlighted on the display screen 800. Next, the finger slides from electrode point 8 to electrode point 6, and leaves the device 200 from there. When the finger slides out of electrode point 8, a negative peak is generated on each of El and E4. When the finger slides onto electrode point 6 and leaves the device 200 from there, successive positive and negative peaks are generated on each of E3 and E4. After detecting electrode point 6, a line is constructed between the current detected point (electrode point 6) and the previous detected point (electrode point 8) through programming on display screen 801. When the finger contacts electrode point 8 again, generating a positive peak on each of El and E4, and then slides from electrode point 8 toward electrode point 4, generating a negative peak on each of El and E4 first, and then a positive peak on each of E2 and E3 when arrived on electrode point 4. With the detected electrode point 4, a line is constructed between electrode point 4 and electrode point 8 through programming on display screen 802. Next, the finger slides from electrode point 4 toward electrode point 2 and leaves the device 200 from there, generating a negative peak on each of E2 and E3, and then consecutive positive and negative peaks on each of El and E2. After detecting electrode point 2, another line is constructed between electrode point 2 and electrode point 4 through programming on display screen 803. Therefore, through directly writing on the device 200 according to an example embodiment, the strokes of character“N” can be successfully constructed on the display screen 803 according to the intuitive finger writing traces.

Similarly, with reference to Fig. 8(b), for writing the character“U”, the finger first taps on electrode point 8 (and then slides sequentially on electrode point 6, electrode point 4 and electrode point 2, following the strokes of “U”. After the detection of electrode point 8, electrode point 6, electrode point 4 and electrode point 2 through the output peaks on the four electrodes El to E4, respective lines are constructed between electrode points 6 and 8, points 4 and 6, and electrode points 2 and 4, forming the complete character“U” on the display screen 804.

In the case of writing character“S”, with reference to Fig. 8(c), some traces are required to be constructed by two adjacent points. Although direct sliding between two adjacent points can be recognized through the pattern of output peaks, the magnitude is rather small which creates difficulty in signal detection and programming. Thus for constructing the traces between two adjacent points, individual tapping is performed on each point according to an example embodiment. In order to write the character“S”, the finger sequentially taps first on electron point 2 (the corresponding point is highlighted on the display screen 805), second on electrode point 1 and lastly on electrode point 8. Respective lines are constructed between electrode points 8 and 1, and electrode points 1 and 2 through programming on display screen 806. When the finger performs the tapping on electrode point 8, it does not leave the device 200 from Point 8 but instead slides to electrode point 4 and leaves from there. A line is constructed between electrode point 8 and electrode point 4 through programming on display screen 807. Next, the finger sequentially taps first on electrode point 5, then on electrode point 6 for completing the writing of “S”. Accordingly, after the detection of each of the writing points, lines are constructed between the current detected point and the previous detected point, forming the strokes of“S” on the display screen 808. Correspondingly, most commonly used characters and symbols can be directly written (combination of tapping and sliding) on the device 200, using it as an intuitive writing pad interface.

Identification code interface according to example embodiments

Due to the sensing capability of different operations, the device 200 according to an example embodiment can be functionalized as the interface of an identification code system, toward potential applications such as security, door access, autonomous express delivery, etc. As illustrated in Fig. 9(a), the eight electrode points and eight outer points are defined as individual regions e.g. 900, 902 to represent one decimal number e.g. 900 or other functional symbol, i.e., “0” -“9”, ”, “+”, “x”, “G, and“=”. In addition, the sixteen points and their corresponding regions e.g. 910, 912 can also be defined as 4-digit binary code (“0000”,“0001”, “0010”,“0011”,“0100”,“0101”,“0110”,“0111”,“1000”,“1001”,“1010”,“1011”,“1100”, “1101”,“1110”, and“1111”) for other coding applications. To activate each number or symbol, the finger is required to slide from the middle point M to the predefined points and leaves the device 200 from there. Fig. 9(b) and (c) indicate the output voltage waveforms for the respective operations on the sixteen points, with the upper row 920 indicated for decimal code, and in the lower row 922 indicated for 4-digit binary code. For the sliding operations onto individual electrode points (“0”,“2”,“4” or“6”) from point M, a small positive peak is first generated on all the four electrodes when the finger contacts the middle point M of the device 200, and then large positive and negative peaks are generated on the corresponding electrode when the finger slides on and leaves, respectively, the individual electrode point. Similarly, for the sliding operations on (common) electrode points (“1”,“3”,“5” or“7”), small positive peaks are also generated first on all the four electrodes when the finger touches point M, and then successive large positive and negative peaks are generated on each of the operated electrodes forming the (common) electrode point.

In terms of sliding to outer points (“8”,“9”,

or“=”), the first generation of small peaks on the four electrodes is the same, noting that the time difference of the successive large positive and negative peaks is less significant since the finger directly slides across the electrode point. In addition, when the finger leaves the device 200 from the outer point, a small negative peak will then be generated on the electrode or two electrodes corresponding to the electrode point closest to the outer point.

Based on the generated signal patterns, activation of different points on the device 200 can be recognized, which can be then used as the interface for inputting the identification code. A conceptual scenario of autonomous express delivery is illustrated in Fig. 9(d), where an autonomous drone 930 is delivering the goods to buyer in a package box 932, with the interacting device 200 according to an example embodiment connecting to an electrical lock 934 of the box 932. Only when the buyer inputs the correct identification code, e.g. provided during purchase of the goods, will the box 932 open for the buyer to retrieve the goods. If the inputting code is incorrect, the box 932 will remain locked to protect the goods. The generated output signals on the four electrodes for an example code (“96632748”) are shown in Fig. 9(e) to unlock the box.

Control interface according to example embodiments

The device 200 according to an example embodiment can also act as a control interface for gaming, entertainment, and robotics, etc. Here, using the device 200 as the interface for wireless vehicle control is demonstrated. As depicted by the block diagram in Fig. 10(a), the complete wireless control system 1000 according to an example embodiments includes the device 200, signal processing circuit 1001, microcontroller unit (MCU) module 1002, wireless transmitter module 1004, wireless receiver module 1006, another MCU module 1008, and a vehicle 1010 as an example of the object being controlled. First, triboelectric output signal is generated from the device 200 when the finger operates on the device 200. Then the output signal will go through the processing circuit 1001 before entering the MCU 1002.

The processing circuit mainly consists of several functional circuit blocks, i.e., bias circuit, amplifier circuit and low-pass filter, in order to filter out the ambient noise and remove the cross-talk between different channels. In an example embodiment, the bias circuit is formed by serial-connected resistors as a voltage divider to provide desired bias for the input triboelectric signals, the amplifier circuit is realized using the typical amplification function of an operational amplifier, in order to provide 10-times signal strength and high signal-to-noise ratio, and the low-pass filter is built by common resistors and capacitors to filter out the high- frequency noises. Thereafter the corresponding signals can be used to trigger various operations.

After detecting the output signal, the MCU 1002 will perform decision making according to the pattern of the output signal. Next, the MCU 1002 will send a decision command to the transmitter module 1004 for wireless transmission. On the vehicle 1010 side, the wireless receiver module 1006 will receive the command and then send it to the MCU 1008. Based on the received command, the MCU 1008 will then generate respective control signals to drive the vehicle 1010 to perform different movements.

Fig. 10(b) to (i) depict the respective control signals from the device 200 for different movement control of the vehicle 1010, i.e., moving forward, moving backward, turning left, turning right, going left front, going right front, going left rear and going right rear. The insets indicate the sliding operations on the device (across the eight electrode points) and the digital photographs of the corresponding vehicle movements.

Sliding operations are adopted according to this example embodiment for the vehicle 200 control due to the higher intuitiveness of control. However, similarly the tapping operations can also be additionally or alternatively applied for the vehicle200 control in different example embodiments.

In one embodiment, an interface device is provided comprising a substrate; an electrode array formed on the substrate; and a material layer formed over the substrate and electrode array, wherein the material layer exhibits a first electron affinity different from a second electron affinity of an object used to operate the interface device using a triboelectric effect; wherein the electrode array comprises a plurality of electrodes arranged to define a substantially continuous pattern around a center point on the substrate; and wherein each electrode comprises a main portion laterally disposed between two finger portions, and respective finger portions of adjacent electrodes laterally overlap for forming the substantially continuous pattern.

The plurality of electrodes may be arranged symmetrically around the center point on the substrate.

The plurality of electrodes may define a substantially circular pattern around the center point on the substrate.

The plurality of electrodes may comprise four electrodes.

The interface device may further comprise a processing unit configured analyzing output signals from the plurality of electrode to determine different tapping and/or sliding operations by the object used to operate the interface device. The processing unit may be configured to identify different action commands based on the determined tapping and/or sliding operations. The action commands may comprise one or more of a group consisting of display control commands, decimal code commands, binary code commands, and movement control commands. The processing unit may be configured to determine the object used to operate the interface device tapping one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

The processing unit may be configured to determine the object used to operate the interface device sliding onto one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

The processing unit may be configured to determine the object used to operate the interface device sliding off one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

The processing unit may be configured to determine the object used to operate the interface device tapping an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

The processing unit may be configured to determine the object used to operate the interface device sliding onto an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

The processing unit may be configured to determine the object used to operate the interface device sliding off an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

The processing unit may be configured to determine the object used to operate the interface device tapping the center point on the substrate based on output signals of the respective electrodes.

The processing unit may be configured to determine the object used to operate the interface device sliding onto the center point on the substrate based on output signals of the respective electrodes.

The processing unit may be configured to determine the object used to operate the interface device sliding off the center point on the substrate based on output signals of the respective electrodes.

The substrate, the electrodes and the material layer may be flexible.

The interface device may be configured as a wearable device.

Figure 11 shows a flow-chart 1100 illustrating a method of fabricating an interface device according to an example embodiment. At step 1102, a substrate is provided. At step 1104, an electrode array is formed on the substrate. At step 1106, a material layer is formed over the substrate and electrode array, the material layer exhibiting a first electron affinity different from a second electron affinity of an object used to operate the interface device using a triboelectric effect; wherein step 1104 comprises arranging a plurality of electrodes, each electrode comprising a main portion laterally disposed between two finger portions, to define a substantially continuous pattern around a center point on the substrate by laterally overlapping respective finger portions of adjacent electrodes.

The method may comprise arranging the plurality of electrodes symmetrically around the center point on the substrate.

The plurality of electrodes may comprise four electrodes.

The method may comprise providing a processing unit configured analyzing output signals from the plurality of electrode to determine different tapping and/or sliding operations by the object used to operate the interface device. The method may comprise configuring the processing unit to identify different action commands based on the determined tapping and/or sliding operations. The action commands may comprise one or more of a group consisting of display control commands, decimal code commands, binary code commands, and movement control commands.

The method may comprise configuring the processing unit to determine the object used to operate the interface device tapping one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

The method may comprise configuring in the processing unit to determine the object used to operate the interface device sliding onto one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

The method may comprise configuring in the processing unit to operate the interface device sliding off one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

The method may comprise configuring in the processing unit to operate the interface device tapping an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

The method may comprise configuring in the processing unit to operate the interface device sliding onto an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

The method may comprise configuring in the processing unit to determine the object used to operate the interface device sliding off an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

The method may comprise configuring in the processing unit to determine the object used to operate the interface device tapping the center point on the substrate based on output signals of the respective electrodes. The method may comprise configuring in the processing unit to determine the object used to operate the interface device sliding onto the center point on the substrate based on output signals of the respective electrodes.

The method may comprise comprising configuring in the processing unit to determine the object used to operate the interface device sliding off the center point on the substrate based on output signals of the respective electrodes.

The substrate, the electrodes and the material layer may be flexible.

The method may comprise configuring the interface device as a wearable device.

In one embodiment, a method of generating action commands using the interface device according to an example embodiment is provided.

Embodiments of the present invention can have one or more of the following features and associated benefits/advantages:

Applications of example embodiments of the present invention include, but are not limited to, writing pad, security, identification, smart control, gaming interface, VR/AR interface, robotics, etc.

The various functions or processes disclosed herein may be described as data and/or instructions embodied in various computer-readable media, in terms of their behavioral, register transfer, logic component, transistor, layout geometries, and/or other characteristics. Computer-readable media in which such formatted data and/or instructions may be embodied include, but are not limited to, non-volatile storage media in various forms (e.g., optical, magnetic or semiconductor storage media) and carrier waves that may be used to transfer such formatted data and/or instructions through wireless, optical, or wired signaling media or any combination thereof. Examples of transfers of such formatted data and/or instructions by carrier waves include, but are not limited to, transfers (uploads, downloads, e-mail, etc.) over the internet and/or other computer networks via one or more data transfer protocols (e.g., HTTP, FTP, SMTP, etc.). When received within a computer system via one or more computer- readable media, such data and/or instruction-based expressions of components and/or processes under the system described may be processed by a processing entity (e.g., one or more processors) within the computer system in conjunction with execution of one or more other computer programs.

Aspects of the systems and methods described herein, such as the processing of the output signals and the generating of the action commands may be implemented as functionality programmed into any of a variety of circuitry, including programmable logic devices (PLDs), such as field programmable gate arrays (FPGAs), programmable array logic (PAL) devices, electrically programmable logic and memory devices and standard cell-based devices, as well as application specific integrated circuits (ASICs). Some other possibilities for implementing aspects of the system include: microcontrollers with memory (such as electronically erasable programmable read only memory (EEPROM)), embedded microprocessors, firmware, software, etc. Furthermore, aspects of the system may be embodied in microprocessors having software -based circuit emulation, discrete logic (sequential and combinatorial), custom devices, fuzzy (neural) logic, quantum devices, and hybrids of any of the above device types. Of course the underlying device technologies may be provided in a variety of component types, e.g., metal-oxide semiconductor field-effect transistor (MOSFET) technologies like complementary metal-oxide semiconductor (CMOS), bipolar technologies like emitter- coupled logic (ECL), polymer technologies (e.g., silicon-conjugated polymer and metal- conjugated polymer-metal structures), mixed analog and digital, etc.

The above description of illustrated embodiments of the systems and methods is not intended to be exhaustive or to limit the systems and methods to the precise forms disclosed. While specific embodiments of, and examples for, the systems components and methods are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the systems, components and methods, as those skilled in the relevant art will recognize. The teachings of the systems and methods provided herein can be applied to other processing systems and methods, not only for the systems and methods described above.

The elements and acts of the various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the systems and methods in light of the above detailed description.

In general, in the following claims, the terms used should not be construed to limit the systems and methods to the specific embodiments disclosed in the specification and the claims, but should be construed to include all processing systems that operate under the claims. Accordingly, the systems and methods are not limited by the disclosure, but instead the scope of the systems and methods is to be determined entirely by the claims.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise," "comprising," and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in a sense of "including, but not limited to." Words using the singular or plural number also include the plural or singular number respectively. Additionally, the words "herein," "hereunder," "above," "below," and words of similar import refer to this application as a whole and not to any particular portions of this application. When the word "or" is used in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list.

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Claims

1. An interface device comprising:

a substrate;

an electrode array formed on the substrate; and

a material layer formed over the substrate and electrode array, wherein the material layer exhibits a first electron affinity different from a second electron affinity of an object used to operate the interface device using a triboelectric effect;

2. The interface device of claim 1, wherein the plurality of electrodes are arranged symmetrically around the center point on the substrate.

3. The interface device of claims 1 or 2, wherein the plurality of electrodes define a substantially circular pattern around the center point on the substrate.

4. The interface device of any one of the preceding claims, wherein the plurality of electrodes comprises four electrodes.

5. The interface device of any one of the preceding claims, further comprising a processing unit configured analyzing output signals from the plurality of electrode to determine different tapping and/or sliding operations by the object used to operate the interface device.

6. The interface device of claim 5, wherein the processing unit is configured to identify different action commands based on the determined tapping and/or sliding operations.

7. The interface device of claim 6, wherein the action commands comprise one or more of a group consisting of display control commands, decimal code commands, binary code commands, and movement control commands.

8. The interface device of any one of claims 5 to 7, wherein the processing unit is configured to determine the object used to operate the interface device tapping one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

9. The interface device of any one of claims 5 to 8, wherein the processing unit is configured to determine the object used to operate the interface device sliding onto one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

10. The interface device of any one of claims 5 to 9, wherein the processing unit is configured to determine the object used to operate the interface device sliding off one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

11. The interface device of any one of claims 5 to 10, wherein the processing unit is configured to determine the object used to operate the interface device tapping an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

12. The interface device of any one of claims 5 to 11, wherein the processing unit is configured to determine the object used to operate the interface device sliding onto an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

13. The interface device of any one of claims 5 to 12, wherein the processing unit is configured to determine the object used to operate the interface device sliding off an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

14. The interface device of any one of claims 5 to 13, wherein the processing unit is configured to determine the object used to operate the interface device tapping the center point on the substrate based on output signals of the respective electrodes.

15. The interface device of any one of claims 5 to 14, wherein the processing unit is configured to determine the object used to operate the interface device sliding onto the center point on the substrate based on output signals of the respective electrodes.

16. The interface device of any one of claims 5 to 15, wherein the processing unit is configured to determine the object used to operate the interface device sliding off the center point on the substrate based on output signals of the respective electrodes.

17. The interface device of any one of the preceding claims, wherein the substrate, the electrodes and the material layer are flexible.

18. The interface device of any one of the preceding claims, configured as a wearable device.

19. A method of fabricating an interface device comprising:

providing a substrate;

forming an electrode array on the substrate; and

forming a material layer over the substrate and electrode array, the material layer exhibiting a first electron affinity different from a second electron affinity of an object used to operate the interface device using a triboelectric effect; wherein forming the electrode array comprises arranging a plurality of electrodes, each electrode comprising a main portion laterally disposed between two finger portions, to define a substantially continuous pattern around a center point on the substrate by laterally overlapping respective finger portions of adjacent electrodes.

20. The method of claim 19, comprising arranging the plurality of electrodes symmetrically around the center point on the substrate.

21. The method of claims 19 or 20, wherein the plurality of electrodes define a substantially circular pattern around the center point on the substrate.

22. The method of any one of claims 19 to 21, wherein the plurality of electrodes comprises four electrodes.

23. The method of any one of claims 19 to 22, comprising providing a processing unit configured analyzing output signals from the plurality of electrode to determine different tapping and/or sliding operations by the object used to operate the interface device.

24. The method of claim 23 , comprising configuring the proces sing unit to identify different action commands based on the determined tapping and/or sliding operations.

25. The method of claim 24, wherein the action commands comprise one or more of a group consisting of display control commands, decimal code commands, binary code commands, and movement control commands.

26. The method of any one of claims 23 to 25, comprising configuring the processing unit to determine the object used to operate the interface device tapping one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

27. The method of any one of claims 23 to 26, comprising configuring in the processing unit to determine the object used to operate the interface device sliding onto one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

28. The method of any one of claims 23 to 27, comprising configuring in the processing unit to operate the interface device sliding off one of the electrodes based on a ratio of output signals of said one electrode and of an adjacent electrode.

29. The method of any one of claims 23 to 28, comprising configuring in the processing unit to operate the interface device tapping an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

30. The method of any one of claims 23 to 29, comprising configuring in the processing unit to operate the interface device sliding onto an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

31. The method of any one of claims 23 to 30, comprising configuring in the processing unit to determine the object used to operate the interface device sliding off an outer point located outside the substantially continuous pattern around the center point on the substrate based on output signals of the respective electrodes.

32. The method of any one of claims 23 to31 , comprising configuring in the processing unit to determine the object used to operate the interface device tapping the center point on the substrate based on output signals of the respective electrodes.

33. The method of any one of claims 23 to 32, comprising configuring in the processing unit to determine the object used to operate the interface device sliding onto the center point on the substrate based on output signals of the respective electrodes.

34. The method of any one of claims 23 to 33, comprising configuring in the processing unit to determine the object used to operate the interface device sliding off the center point on the substrate based on output signals of the respective electrodes.

35. The method of any one of claims 19 to 34, wherein the substrate, the electrodes and the material layer are flexible.

36. The method of any one of claims 19 to 35, comprising configuring the interface device as a wearable device.

37. A method of generating action commands using the interface device of any one of claims 1 to 18.