WO2021212272A1 - Sensor for detection of proximity and contact, and manufacturing method therefor - Google Patents

Abstract

Disclosed are a sensor for the detection of proximity and contact, and a manufacturing method therefor. The sensor comprises a sensing material layer and a wire, wherein the sensing material layer is of a dipped paper material, and same is connected to the wire; and the wire is used for transmitting a sensed signal to an external device. The sensor has a low cost, simple and diverse processing manners, and high detection efficiency, and can be used for the detection of the proximity and contact of a human body and for further developing a flexible human-computer interaction interface.

Description

Sensor for proximity contact detection and preparation method thereof Technical field

The present invention relates to the technical field of flexible electronics, and more specifically, to a sensor for proximity contact detection and a preparation method thereof.

Background technique

The human-computer interaction interface that realizes information exchange between the human body and electronic devices can provide people with a more efficient, diverse and convenient lifestyle. Since it can provide one-way or two-way information exchange between humans and machines, the human-computer interaction interface based on human physiological signal detection enables people to use electronic products more efficiently, which greatly enriches and facilitates people's lives. Flexible proximity sensors have a profound impact on human-computer interaction interfaces such as safety protection and smart electronics. Due to its light, thin and bendable characteristics, flexible electronics provides more diverse device options and application scenarios for human-computer interaction interfaces. Flexible non-contact proximity sensors can sense the proximity of objects, can provide higher-dimensional sensing capabilities and richer operating experience than traditional contact sensors, and can provide a wider range of application scenarios than non-flexible proximity sensors. For safety protection, Human-computer interaction interfaces such as smart electronics have a profound impact.

At present, the sensing mechanisms of flexible proximity sensors used to detect the proximity of the human body mainly include capacitive and triboelectric types. For capacitive proximity sensors, when the surface of the human body carrying negative charges approaches the capacitor, these negative charges will terminate the power line from the positive electrode of the capacitor, reducing the induced charge of the negative electrode, thereby reducing the capacitance of the capacitor and achieving proximity sensing. The triboelectric proximity sensor relies on the electrostatic induction caused by the charge on the surface of the human body to cause the potential change of the sensing material in the triboelectric nanogenerator. In addition to proximity sensing based on capacitive and triboelectric mechanisms, there are a few flexible proximity sensors that implement proximity sensing to the human body based on some other mechanisms (such as humidity, electromagnetic field changes, etc.).

In the prior art, flexible proximity sensors usually use expensive low-dimensional materials, such as graphene and silver nanowires. In addition, the manufacturing process of flexible proximity sensors often uses time-consuming and expensive micro-nano manufacturing processes. These factors have led to the high cost of existing flexible proximity sensors, and have restricted the further commercialization of flexible sensors and their entry into people's lives and work. Therefore, it is necessary to improve the existing technology to reduce the manufacturing cost of the flexible proximity sensor and improve the manufacturing efficiency, and promote the flexible sensor to be more widely used.

Summary of the invention

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, and provide a sensor for proximity contact detection and a preparation method thereof, which is a new technical solution for processing key sensing materials through a filter paper-based solution.

According to a first aspect of the present invention, a sensor for proximity contact detection is provided. The sensor includes a flexible wire and a sensing material layer, wherein the sensing material layer is a paper material that has been soaked, and the sensing material layer is connected to a wire, and the wire is used to transmit the sensed material to an external device. Signal.

According to the second aspect of the present invention, a sensor preparation method is provided for preparing the sensor of the present invention, and the method includes the following steps:

PVA soaking liquid for making sensing materials;

Mix the PEDOT/PSS conductive polymer solution and the PVA soaking solution according to the set volume percentage y:1, and soak the filter paper in the mixed solution for a period of z minutes;

Take out the filter paper and let it stand for a period of time in a normal temperature and pressure environment α;

Cut or laser cut the filter paper according to the required style.

In one embodiment, α is set to 1 to 100 hours.

In one embodiment, y is set to 5-50.

In one embodiment, z is set from 2 to 100 minutes.

In one embodiment, making the PVA soaking liquid includes dissolving the PVA powder in deionized water, setting the mass ratio to 1:x, and stirring at a set temperature to dissolve.

In one embodiment, x is set from 10 to 100, and the set temperature is 80°C.

According to the third aspect of the present invention, there is provided a method for preparing a sensor for the sensor of the present invention, and the method includes the following steps:

PVA soaking liquid for making sensing materials;

Use an inkjet printer to deposit PEDOT/PSS conductive polymer ink in the filter paper according to the set graphic pattern;

Soak the filter paper with PEDOT/PSS conductive polymer ink in the PVA soaking solution for a period of time;

Place the soaked filter paper under normal temperature and pressure for a period of time;

Connect wires with copper tape at both ends of the obtained sample to obtain a sensor for proximity contact detection.

In one embodiment, the time for soaking the filter paper in the PVA solution is set to 10 minutes.

In one embodiment, the time for placing the soaked filter paper under normal temperature and pressure is set to 1 to 100 hours.

Compared with the prior art, the present invention has the advantages of low cost, simple and diverse processing methods, high detection efficiency, and can be used for human proximity and contact detection and can be used for further development of flexible human-computer interaction interfaces.

Through the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, other features and advantages of the present invention will become clear.

Description of the drawings

The drawings incorporated in the specification and constituting a part of the specification illustrate the embodiments of the present invention, and together with the description are used to explain the principle of the present invention.

Fig. 1 is a flow chart of a method for manufacturing a sensor for proximity contact detection according to an embodiment of the present invention;

2 is a flowchart of a method for manufacturing a sensor for proximity contact detection according to another embodiment of the present invention;

3 is a schematic diagram of the response of the sensor provided by the present invention to the approach of a finger;

4 is a schematic diagram of the response speed and response distance of the sensor provided by the present invention to the approach of a finger;

Fig. 5 is a test effect diagram of the sensor provided by the present invention on the ability of finger proximity-contact discrimination;

In the figure, Sensor-sensor; Time-time; Distance-distance; Contact-contact; fingerremoves-finger movement; Response time-response time; Recovery time-recovery time; Experimental Data-test data; Fitting line-fitting line .

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless specifically stated otherwise, the relative arrangement of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.

The following description of at least one exemplary embodiment is actually only illustrative, and in no way serves as any limitation to the present invention and its application or use.

The technologies, methods, and equipment known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be regarded as part of the specification.

In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiment may have different values.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

In the present invention, the key sensor material PEDOT/PSS (poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate))-PVA (polyvinyl alcohol) composite filter paper is prepared, and further This material is prepared into a flexible paper-based PEDOT/PSS-PVA proximity/touch sensor (Paper-based PEDOT/PSS-PVA Proximity/touch Sensor, also referred to herein as a 3P sensor). Subsequently, using the printability and cutting characteristics of paper, the sensors are made into different styles and shapes by cutting, inkjet printing and other methods.

For example, the manufactured sensor includes a wire and a sensing material layer, wherein the sensing material layer is connected to the wire. In the present invention, the sensing material layer is a processed paper material, for example, after soaking in a PEDOT/PSS-PVA solution The filter paper sensing material has flexibility and sensing functions at the same time.

Specifically, referring to FIG. 1, in one embodiment, the method for preparing the sensor provided by the present invention includes the following steps:

In step S110, a PVA solution is produced.

In this step, the soaking liquid of the sensing material is made. For example, the PVA powder is dissolved in deionized water at a mass ratio of 1:x (x is set to 10 to 100), and stirred at 80°C until dissolved.

Step S120, making a PEDOT/PSS-PVA solution.

Subsequently, the PEDOT/PSS conductive polymer solution and the PVA solution are mixed in a volume ratio of y:1 (y is from 5 to 50) to make a mixed solution.

Step S130, soak the filter paper in the PEDOT/PSS-PVA solution.

After the mixed solution is obtained, the filter paper is soaked in the fusion solution for a period of time z and then taken out, z can be set to 2 to 100 minutes.

Step S140, placing the soaked filter paper under normal temperature and pressure.

The soaked filter paper is allowed to stand for a period of time α in a laboratory environment (ie, a normal temperature and pressure environment) at room temperature, for example, α can be set to 1 to 100 hours.

In step S150, a sensor for proximity contact detection is made.

After the above process, the soaked filter paper can be cut or laser cut into a desired pattern to further manufacture a flexible proximity sensor.

In another embodiment, inkjet printing technology can also be used to prepare the sensor. As shown in FIG. 2, the preparation process includes the following steps:

Step S210, making PVA solution

The same method as in step S110 can be used to prepare a PVA solution for soaking the sensing material.

Step S220, using inkjet printing technology to print the PEDOT/PSS solution pattern on the filter paper.

Using inkjet printing method, use inkjet printer to deposit PEDOT/PSS conductive polymer ink in the filter paper according to the set pattern.

Step S230, soak the printed filter paper in the PVA solution.

In this step, the filter paper on which the PEDOT/PSS conductive polymer ink is deposited is soaked in the PVA solution for a period of time, for example, 10 minutes.

In step S240, the soaked filter paper is placed under normal temperature and pressure.

After removing the filter paper from the PVA solution, let it stand for a period of time α, such as 1 to 100 hours, in a laboratory environment at room temperature.

Step S250, making a sensor for proximity contact detection

After the key sensing materials are obtained through the above process, the flexible proximity sensor can be further manufactured. For example, a 3P sensor can be made by connecting both ends of the sample with copper tape to the wire.

The sensor provided by the present invention can be used in a variety of scenarios, including but not limited to:

1) The proximity alarm is designed according to the proximity of the human body. For example, when the human body is close to dangerous objects (high temperature, toxic substances, etc.), the response signal of the sensor is used to issue operating instructions to the alarm, and the alarm is used to remind people to stay away from dangerous objects;

2) According to the sensor's ability to distinguish between proximity and contact, a multi-level response safety protection system is designed to meet the multi-level safety protection requirements for proximity-contact. For example, when criminals approach a protected object, they will issue a secondary response (buzzer, voice prompts, etc.), when criminals touch a protected object, take protective measures (drive a counterattack device or automatically strengthen the protection level);

3) In a production environment where humans and machines cooperate with each other, mechanical failures or irregular operations by operators may cause damage to the production personnel by the machine. For this reason, the proximity sensor can be attached to the surface of the machine, and the safety of the machine and the human body can be set. Distance threshold. When the distance between the machine and the person is less than this threshold, the machine will send an instruction to stop the operation to protect the safety of production personnel;

4) On the basis of a single device, further develop a multi-channel proximity sensor system;

5) Using the multi-channel sensor system, the threshold value is set separately for each channel. If the threshold value is exceeded, a note output will be generated, realizing the so-called "playing the piano in the air", expanding the traditional music performance experience and making the performance more interesting.

Compared with the existing sensors for sensing the proximity of the human body, the 3P sensor provided by the present invention has a longer detection distance under the similar sensor size. In order to further verify the technical effect, the inventor designed and performed several experiments, which confirmed that the 3P sensor provided by the present invention has a significant electrical signal response to the proximity of the human body.

Fig. 3 is a schematic diagram of the response of the sensor provided by the present invention to the approach of a finger, in which Fig. 3(a) is a schematic diagram of the test system, Fig. 3(b) is the sensor response curve of the finger at different distances, and Fig. 3(c) is the signal amplitude In relation to the distance of the finger, Figure 3(d) shows the signal response caused by the finger gradually approaching the sensor. For example, select a 4cm×4cm square 3P sensor manufactured by the method shown in Figure 1 for quantitative experiments. Specifically, the sensor is fixed on an insulating plastic board and connected to the LCR bridge, and the high-frequency impedance (f=100kHz) of the 3P sensor is tested for the response signal of the finger approach, as shown in Figure 3(a). Place the index finger at a distance of 12, 8, 5, 4, 3, 2, 1, 0.5 cm from the sensor one by one, stay for about 18 seconds, and observe the response of the sensor's high-frequency impedance signal ΔR/R0 to the finger at these positions. Experiments have found that when the finger appears in these positions, the high-frequency signal of the sensor has an obvious response, and the closer the finger is to the sensor, the _{greater the response value of ΔR/R 0} , as shown in Figure 3(b), indicating that the 3P sensor can The proximity of the finger is sensed, and the smaller the distance, the greater the signal strength. Subsequently, 6 samples were selected for the response level of the finger at each distance, and their average value was taken to explore whether the ΔR/R ₀ response of the sensor has a functional relationship with the distance of the finger. It can be clearly seen from Figure 3(c) that ΔR/R ₀ not only increases with the approach of the finger, but also through function fitting, it can be seen that the fitted curve is very close to the experimental value (R ² =0.96 ), indicating that the distance between ΔR/R0 and the finger is an exponential relationship. This shows that the provided sensor can not only detect the proximity of the finger, but also distinguish the distance between the finger and the sensor. In addition, gradually approach the sensor from far to near, and stay at 12, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5 (in cm) for 5 seconds, and get The stepped signal shown in Figure 3(d) shows that the sensor can stably detect the gradual approach of the finger, and when the finger moves far away, the signal change amplitude is small, and when the finger moves at a close distance, the signal change amplitude is larger. It conforms to the exponential relationship between distance and signal strength. The results in Figure 3 show that the 3P sensor can be used for quantitative detection of human proximity.

Figure 4 is a schematic diagram of the response speed and response distance of the sensor provided by the present invention to the approach of a finger. Figure 4(a) is the response of the 3P sensor to the finger at a distance of 20cm, and Figure 4(b) is at a distance of 5cm. Fast response, Figure 4(c) is a schematic diagram of the cycle stability test repeated nearly 100 times. For example, through experiments, we also searched for the maximum sensing distance of the 3P sensor, and found that even if the finger is placed 20cm away from the sensor, the sensor can still sense the presence of the finger, as shown in Figure 4(a). In addition, in order to further explore the response speed of the 3P sensor. The experimenter placed the finger at a distance of 5 cm from the sensor for 10 seconds, then moved it away, and recorded the signal changes during this process. It is found that the sensor has an obvious response to the appearance of the finger within 0.25s, and the response quickly disappears within 0.15s after the finger is removed, as shown in Figure 4(b). It is worth mentioning that the sensor will respond when the finger approaches and moves away, so the actual response time should be shorter than the recorded time. The results in Figure 4 show that the 3P sensor has a relatively fast response speed and meets the needs of most application scenarios. In order to test the stability of the 3P sensor in cyclic use, the experimenter placed the finger at a distance of 5cm from the sensor, and then quickly moved the finger away from the sensor. This process was repeated 100 times, and the entire cycle process was recorded by the sensor, as shown in the figure. As shown in 4(c), it can be seen that the sensor has a stable and consistent response to multiple approaches of the finger, indicating that the sensor has good cyclic stability.

Figure 5 is a schematic diagram of the test effect of the provided sensor on the ability of finger proximity-contact discrimination, where Figure 5(a) is the signal response of the 3P sensor during the finger "distance 0.1cm-contact-distance 0.1cm", Figure 5( b) is the statistical histogram (Mean±se) of the signal level of the sensor in the process of Figure 5(a), and Figure 5(c) is the stability test of the 3P sensor finger during the "distance 0.1cm-contact" cycle. Specifically, in order to verify whether the sensor can distinguish whether the finger touches the sensor, first place the fingertip of the finger at a distance of 0.1cm from the sensor (the minimum distance that the actual test can operate), and after staying for 5s, immediately touch the finger directly to the sensor and stay About 6s, then place it at 0.1cm and stay for 5s while recording the high-frequency impedance response of the sensor during the whole process. Experiments have found that when the finger touches the sensor, the electrical signal of the device rises significantly, and returns to the original level after the finger returns to a distance of 0.1cm, as shown in Figure 5(a). On this basis, we calculated the signal level of 4 3P sensors of the same specification for the finger at a distance of 0.1cm and at the time of contact, and plotted a statistical histogram. It was found that the average impedance change rate of the 3P sensor at the time of finger contact was 0.31. The average rate of change at a distance of 0.1cm is 0.11, and the average value of the former is about 3 times that of the latter, as shown in Figure 5(b). The experimental results show that the 3P sensor can significantly distinguish whether the finger touches the sensor. At the same time, in order to verify the cyclic stability of the proximity-contact discrimination ability of the 3P sensor, the tester first put his finger at a position of 0.1cm, then quickly touched the sensor, and then quickly returned to the position of 0.1cm, repeating this process 50 times, Figure 5 (c) It is the signal change of the whole process recorded by the 3P sensor. It can be seen that the response of the sensor is very stable during this period. The above results show that the 3P sensor can stably distinguish whether the finger touches the sensor.

In a word, it has been verified by experiments that the prepared 3P sensor has a significant response to the approach of the human body, and the maximum response distance is 20cm. As the human body gradually approaches, the sensor response signal strength is stronger. In addition, the 3P sensor has a more significant ability to distinguish between human proximity and contact.

In summary, the present invention uses paper materials to make sensors with many advantages. First, the natural, broad, and renewable sources of materials make paper-based sensors very low-cost. Second, its biodegradable and recyclable characteristics make the disposal of paper-based electronic waste more environmentally friendly and lower in cost. Third, people can use more low-cost manufacturing methods (such as large-area soaking, printing, etc.) to manufacture paper-based sensors, and the hydrophilicity of paper, three-dimensional permeable hierarchical porous structure and larger surface area make functional fillers It is easier to be absorbed, and the bond is stronger. Fourth, the components of paper have excellent chemical and thermal stability, which can broaden the application scenarios of paper agent sensors. Fifth, the foldable and cuttable characteristics of paper enable paper-based sensors to break through the style of traditional devices and derive richer user experience and application scenarios. Therefore, the sensor provided by the present invention has the advantages of low cost, easy processing, and compatibility with multiple processing methods, and can produce more novel sensors with lower time, material, and cost, thereby expanding the application scenarios of flexible proximity sensors.

The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Without departing from the scope and spirit of the illustrated embodiments, many modifications and changes are obvious to those of ordinary skill in the art. The choice of terms used herein is intended to best explain the principles, practical applications, or technical improvements in the market of the various embodiments, or to enable other ordinary skilled in the art to understand the various embodiments disclosed herein. The scope of the invention is defined by the appended claims.

Claims (10)

1. A sensor for proximity contact detection, comprising a flexible wire and a sensing material layer, wherein the sensing material layer is a paper material that has been soaked, and the sensing material layer is connected to a wire, and the wire is used for Transmit the sensed signal to the external device.
2. A method for preparing a sensor for preparing the sensor according to claim 1, the method comprising the following steps:

   PVA soaking liquid for making sensing materials;

   Mix the PEDOT/PSS conductive polymer solution and the PVA soaking solution according to the set volume percentage y:1, and soak the filter paper in the mixed solution for a period of z minutes;

   Take out the filter paper and let it stand for a period of time in a normal temperature and pressure environment α;

   Cut or laser cut the filter paper according to the required style.
3. The sensor manufacturing method according to claim 2, wherein α is set to 1 to 100 hours.
4. The sensor manufacturing method according to claim 2, wherein y is set to 5-50.
5. The sensor manufacturing method according to claim 2, wherein z is set to 2 to 100 minutes.
6. The sensor preparation method according to claim 2, wherein the preparation of the PVA soaking liquid comprises dissolving the PVA powder in deionized water with a mass ratio of 1:x, and stirring at a set temperature to dissolve.
7. The sensor manufacturing method according to claim 6, wherein x is set to 10 to 100, and the set temperature is 80°C.
8. A method for preparing a sensor for preparing the sensor according to claim 1, the method comprising the following steps:

   PVA soaking liquid for making sensing materials;

   Use an inkjet printer to deposit PEDOT/PSS conductive polymer ink in the filter paper according to the set graphic pattern;

   Soak the filter paper with PEDOT/PSS conductive polymer ink in the PVA soaking solution for a period of time;

   Place the soaked filter paper under normal temperature and pressure for a period of time;

   Connect wires with copper tape at both ends of the obtained sample to obtain a sensor for proximity contact detection.
9. The sensor preparation method according to claim 8, wherein the time for soaking the filter paper in the PVA solution is set to 10 minutes.
10. The sensor preparation method according to claim 8, wherein the time for placing the soaked filter paper under normal temperature and pressure is set to 1 to 100 hours.

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