WO2017161975A1

WO2017161975A1 - Thickness detection device

Info

Publication number: WO2017161975A1
Application number: PCT/CN2017/073236
Authority: WO
Inventors: 姜利; 张凯
Original assignee: 威海华菱光电股份有限公司
Priority date: 2016-03-25
Filing date: 2017-02-10
Publication date: 2017-09-28
Also published as: CN105806206A; CN105806206B

Abstract

A thickness detection device, comprising: a common electrode (100); a detection electrode (201) corresponding to the common electrode (100) and arranged at a spacing relative to the common electrode, wherein a detection channel is formed between the detection electrode (201) and the common electrode (100); a compensation electrode (202) corresponding to the common electrode (100) and arranged at a spacing relative to the common electrode, wherein the compensation electrode (202) is arranged outside the detection channel; and a control portion electrically connected to the common electrode (100), the detection electrode (201) and the compensation electrode (202) and used for compensating for an output of the detection electrode (201) according to an output of the compensation electrode (202). Since the compensation electrode (202) is arranged outside the detection channel, and an object to be detected does not pass through the compensation electrode (202) when passing through the detection channel, when the detection electrode (201) detects the object to be detected, the compensation electrode (202) can feed back an electrical characteristic change caused due to external interference, and the control portion uses a signal detected by the compensation electrode (202) to compensate for the signal detected by the detection electrode (201), so as to prevent an electrical signal for reflecting the thickness of the object to be detected from being influenced by external interference, and obtain a thickness value with higher accuracy.

Description

Thickness detecting device

Technical field

The present invention relates to the field of electromechanical, and in particular to a thickness detecting device.

Background technique

Thickness detecting devices have a wide range of applications, such as continuous thickness measurement of sheet-like articles such as paper, bills, plastic films, textile articles, etc., which are playing an increasingly important role in the production, testing, processing, recycling and the like.

In the prior art, there is a technique for detecting the thickness of a film by electrostatic induction between electrodes, one of which is to use a plate of a plate capacitor as a sensitive device for thickness detection, so that the object to be detected passes between the two plates, and the object is actually measured. The displacement of the capacitive active plate caused by the thickness variation causes the capacity of the panel capacitor to change. Another detecting device uses a common common electrode and a detecting electrode to form a detecting channel. When the object to be tested passes through the detecting channel, the dielectric constant of the medium between the two electrodes is changed, so that the amount of charge induced on the detecting electrode is also With the change, the thickness of the detection object is different, the dielectric constant between the two electrodes is also different, and the amount of charge induced on the detection electrode is also different. Therefore, by detecting the magnitude of the electrical signal of the electrode, the thickness of the detection object is calculated. .

However, the thickness detecting device using the electrical characteristics in the prior art is subject to interference from the external environment, such as temperature, humidity, and noise. The interference causes the detected electrical signal to change, and the accuracy of the detection is destroyed.

Summary of the invention

It is a primary object of the present invention to provide a solution to the problems of the prior art.

In order to achieve the above object, the present invention provides a thickness detecting device comprising: a common electrode; a detecting electrode corresponding to the common electrode and spaced apart from each other, a detecting channel formed between the detecting electrode and the common electrode; a correction electrode, and a common electrode Correspondingly and spaced apart from each other, the correction electrode is disposed outside the detection channel; the control unit is electrically connected to the common electrode, the detection electrode, and the correction electrode for correcting the output of the detection electrode according to the output of the correction electrode.

Further, the electrical characteristics formed between the correction electrode and the common electrode are the same as those formed between the detection electrode and the common electrode.

Further, the size of the correction electrode is the same as the size of the detection electrode, and the distance between the correction electrode and the common electrode is equal to the distance between the detection electrode and the common electrode.

Further, the correction electrode is disposed spaced apart from the detection electrode in a direction perpendicular to the extending direction of the detection channel.

Further, the detecting electrodes are plural, and the plurality of detecting electrodes are arranged side by side, and the extending direction of the detecting channels is an arrangement direction of the plurality of detecting electrodes.

Further, the thickness detecting device further includes a first protecting portion disposed outside the common electrode, and/or a second protecting portion disposed outside the detecting electrode.

Further, the thickness detecting device further includes a second protecting portion disposed outside the detecting electrode and a third protecting portion disposed outside the correcting electrode, covering a thickness of the second protecting portion on the outer surface of the detecting electrode facing the common electrode The thickness of the third protective portion covering the outer surface of the correction electrode facing the common electrode is equal.

Further, the thickness detecting device further includes: a first conductive portion disposed on an outer surface of the common electrode facing the detecting electrode; a second conductive portion disposed on an outer surface of the detecting electrode facing the common electrode; and a third conductive portion, And disposed on an outer surface of the correction electrode facing the common electrode; wherein the second conductive portion is the same size as the third conductive portion.

Further, the control unit includes a differential circuit, and the input ends of the differential circuits are electrically connected to the detection electrodes and the correction electrodes, respectively, and the difference circuit obtains an output value according to a difference between an output of the detection electrodes and an output of the correction electrodes.

Further, the control unit includes: a detection displacement output circuit, the input end is electrically connected to the detection electrode, and is used for outputting an electrical signal generated between the detection electrode and the common electrode; and correcting the displacement output circuit, the input end is electrically connected with the correction electrode, and is used for An electrical signal generated between the correction electrode and the common electrode is output.

According to the technical solution of the present invention, the thickness detecting device performs thickness detection by changing electrical characteristics, that is, a detecting channel is formed between the common electrode and the detecting electrode, and the electrical property between the common electrode and the detecting electrode is changed from the detecting channel by the object to be detected. The thickness of the object to be detected is obtained by the change in the electrical characteristics. In addition, the thickness detecting device of the present invention is further provided with a correction electrode. Since the correction electrode is disposed outside the detection channel, the object to be detected does not pass through the correction electrode when passing through the detection channel. Therefore, when the detection electrode detects the object to be detected, the correction electrode is corrected. The control unit can feedback the change of the electrical characteristics caused by the external interference, and the control unit corrects the signal detected by the detecting electrode by using the signal detected by the correcting electrode, thereby preventing the electrical signal reflecting the thickness of the object to be detected from being affected by external interference, and obtaining more authenticity. High thickness value.

DRAWINGS

The accompanying drawings, which are incorporated in the claims of the claims In the drawing:

Figure 1 shows a front view of an embodiment of a thickness detecting device according to the present invention;

2 is a schematic view showing the layout of the second substrate of FIG. 1;

Figure 3 is a view showing the logical relationship of the control portion of the thickness detecting device according to the present invention;

Fig. 4 shows a front view of another embodiment of a thickness detecting device according to the present invention.

Wherein, the above figures include the following reference numerals:

100, a common electrode; 201, a detecting electrode; 202, a correcting electrode; 11, a first frame; 12, a first substrate; 14, a first protection portion; 15, a first conductive portion; 21, a second frame; a second substrate; 23, a circuit component; 24, a second protection portion; 25, a second conductive portion; 26, a third conductive portion.

detailed description

It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. The invention will be described in detail below with reference to the drawings in conjunction with the embodiments.

The present invention provides a thickness detecting device. As shown in FIGS. 1 to 4, the thickness detecting device includes: a common electrode 100; and detecting electrodes 201 corresponding to the common electrode 100 and spaced apart from each other, and the detecting electrode 201 and the common electrode 100 Forming a detection channel; the correction electrode 202 is disposed corresponding to the common electrode 100 and spaced apart from each other, and the correction electrode 202 is disposed outside the detection channel; and the control portion is electrically connected to the common electrode 100, the detection electrode 201, and the correction electrode 202, It is used to correct the output of the detecting electrode 201 in accordance with the output of the correcting electrode 202.

The thickness detecting device of the present invention performs thickness detection using a change in electrical characteristics, that is, a detecting channel is formed between the common electrode 100 and the detecting electrode 201, and the electrical property between the common electrode 100 and the detecting electrode 201 is changed from the detecting channel by the object to be detected. The thickness of the object to be detected is obtained by the change in the electrical characteristics. In addition, the thickness detecting device of the present invention is further provided with a correction electrode 202. Since the correction electrode 202 is disposed outside the detection channel, the object to be detected does not pass through the correction electrode 202 when passing through the detection channel, so the detection electrode 201 is detected at the detection electrode 201. When the correction electrode 202 can feedback the change of the electrical characteristic due to the external interference, the control unit corrects the signal detected by the detection electrode 201 by using the signal detected by the correction electrode 202, thereby avoiding the external signal that the electrical signal reflecting the thickness of the object to be detected is subjected to external interference. The effect is to get a true thickness value.

Specifically, a plate capacitor is formed between the detecting electrode 201 and the common electrode 100, and a gap between the two is a medium of the capacitor. When the object to be detected passes through the gap, the object to be detected constitutes a part of the capacitor. Therefore, the electrical characteristics of the capacitor are changed. If the charge is applied to the detecting electrode 201 and the common electrode 100 at this time, the charge is changed. In the embodiment of the present invention, the control portion is used to detect the detecting electrode 201 and the common A voltage signal between the electrodes 100. The external interference can change the electrical characteristics of the plate capacitor formed by the detecting electrode 201 and the common electrode 100, such as temperature, humidity, vibration noise, electromagnetic noise, etc., and correct the plate capacitance formed between the electrode 202 and the common electrode 100. It is possible to reflect the change in electrical characteristics caused by such external disturbances, that is, to correct the electrical signal output of the plate capacitor formed between the detecting electrode 201 and the common electrode 100 by using the electrical signal output of the plate capacitor formed between the correcting electrode 202 and the common electrode 100. The effect of removing at least a portion of the external disturbance can be achieved, so that the detected thickness signal is more accurate.

Preferably, the electrical characteristics formed between the correction electrode 202 and the common electrode 100 are the same as those formed between the detection electrode 201 and the common electrode 100. In order to more accurately reflect the influence of external interference on the electrical signal outputted by the detecting electrode 201, the electrical characteristics formed between the correcting electrode 202 and the common electrode 100 are the same as those formed between the detecting electrode 201 and the common electrode 100, specifically It is to say that the performance of the plate capacitor formed between the correction electrode 202 and the common electrode 100 is the same as the performance of the plate capacitor formed between the detection electrode 201 and the common electrode 100. Under the same conditions, the output of the detection electrode 201 and the correction electrode 202 are output. The electrical signals are the same.

In order to achieve the above effects, more specifically, the size of the correction electrode 202 is the same as the size of the detection electrode 201, and the distance between the correction electrode 202 and the common electrode 100 is equal to the distance between the detection electrode 201 and the common electrode 100. Further, the materials of the correction electrode 202 and the detection electrode 201 are also the same.

Preferably, as shown in FIG. 2, the correction electrode 202 is disposed spaced apart from the detection electrode 201 in a direction perpendicular to the extending direction of the detection channel. Since the detection channel is formed between the detection electrode 201 and the common electrode 100, the correction electrode 202 is disposed offset from the detection channel.

More specifically, the detection electrodes 201 are plural, and the plurality of detection electrodes 201 are arranged side by side, and the direction in which the detection channels extend is the arrangement direction of the plurality of detection electrodes 201. The plurality of detecting electrodes 201 are arranged in a queue and form a detecting channel with the common electrode 100, and the correcting electrode 202 is spaced apart from the plurality of detecting electrodes 201 in a direction perpendicular to the detecting channel, thereby avoiding the detecting channel. In the embodiment shown in Fig. 2, the correction electrode 202 is also disposed outside the end of the detection channel in the longitudinal direction of the detection channel. More specifically, the correction electrode 202 is disposed at an edge portion of the substrate in the longitudinal direction of the detection channel.

In some embodiments, the end surface of the detecting electrode 201 or the common electrode 100 is in a bare arrangement, that is, the detecting electrode 201 or the outside of the common electrode 100 is not provided with a protective portion, such as the embodiment shown in FIG.

In still other embodiments, the thickness detecting device further includes a first protecting portion 14 disposed outside the common electrode 100, and/or a second protecting portion 24 disposed outside the detecting electrode 201.

In order to avoid the detection error caused by the abrasion of the electrode, a protection portion may be provided on the outer side of the electrode to prevent the object to be detected from abrading the electrode, and the accuracy of the thickness detection is improved. A protective portion may be provided for the electrode that needs to be in contact with the object to be detected, or a protective portion may be provided for both electrodes.

For example, as shown in FIG. 4, a first protection portion 14 is disposed on the outer side of the common electrode 100, and a second protection portion 24 is disposed on the outer side of the detection electrode 201. The first protection portion 14 and the second protection portion 24 may be It is a thin coating layer.

Preferably, the thickness detecting device further includes a second protecting portion 24 disposed outside the detecting electrode 201 and a third protecting portion disposed outside the correcting electrode 202 covering the second surface of the detecting electrode 201 facing the outer surface of the common electrode 100 The thickness of the protection portion 24 is equal to the thickness of the third protection portion covering the outer surface of the correction electrode 202 facing the common electrode 100.

Although the correction electrode 202 does not wear out, since the detection electrode 201 is provided with the second protection portion 24, in order to make the correction electrode 202 and the detection electrode 201 the same, a third protection portion is also disposed outside the correction electrode 202, The thicknesses, materials, and the like of the third protection portion and the second protection portion 24 are the same. In the embodiment shown in Figure 4, the second protection portion 24 and the third protection portion are the same coating layer.

Preferably, in the embodiment shown in FIG. 4, the thickness detecting device further includes: a first conductive portion 15 disposed on an outer surface of the common electrode 100 facing the detecting electrode 201; and a second conductive portion 25 disposed at the detecting electrode The second conductive portion 26 is disposed on the outer surface of the correction electrode 202 facing the common electrode 100; wherein the second conductive portion 25 is the same size as the third conductive portion 26.

In order to increase the sensitivity of the electrodes of the thickness detecting device, when the object to be detected passes between the common electrode 100 and the detecting electrode 201, the detecting electrode 201 gives a more sensitive reaction, specifically to the plate capacitor, that is, the detecting electrode 201 and the common electrode 100. The induced charge between the two can be rapidly accumulated so that the output voltage is rapidly increased correspondingly, thereby improving the sensitivity of the entire thickness detecting device. As shown in the embodiment of FIG. 4, the first conductive portion 15 is disposed on the end surface of the common electrode 100, Detection of electricity The second conductive portion 25 is disposed on the end surface of the pole 201, wherein the conductive portion is a conductive film made of a highly conductive material, including gold or silver.

In order to increase the sensitivity of the thickness detecting device, it is possible to provide only the conductive portions on the end faces of the common electrode 100 and the detecting electrode 201. In the embodiment shown in FIG. 4, for the accuracy of the correction, that is, the correction electrode 202 and the detection electrode 201 maintain the same sensitivity and capacitance capacity, the third conductive portion 26 is also disposed on the end surface of the correction electrode 202, and The third conductive portion 26 and the second conductive portion 25 have the same specifications.

When a certain electrode of the thickness detecting device is provided with a conductive portion and a protective portion is further provided, the protective portion is located outside the conductive portion.

Preferably, as shown in FIG. 3, the control portion includes a differential circuit, and the input terminals of the differential circuit are electrically connected to the detecting electrode 201 and the correcting electrode 202, respectively, and the difference circuit is based on the difference between the output of the detecting electrode 201 and the output of the correcting electrode 202. The value gets the output value. It should be noted that in some embodiments, the differential circuit also has an amplification function and is therefore a differential amplification circuit.

In this embodiment, the control unit further includes: a detection displacement output circuit, wherein the input end is electrically connected to the detection electrode 201, respectively, for outputting an electrical signal generated between the detection electrode 201 and the common electrode 100; the correction displacement output circuit, the input end It is electrically connected to the correction electrode 202 for outputting an electrical signal generated between the correction electrode 202 and the common electrode 100.

For an embodiment of the thickness detecting device having a plurality of detecting electrodes 201 as shown in FIG. 2, the input end of the detecting displacement output circuit is electrically connected to the output end of each detecting electrode 201, and the plurality of detecting electrodes 201 are sequentially arranged. Forming the detection channel, the more the number of electrodes in the unit length, the higher the resolution of the detecting device, and the function of detecting the displacement output circuit is to sequentially output the signals of the plurality of detecting electrodes 201 simultaneously outputted to facilitate the signal. deal with.

According to the embodiment shown in FIGS. 1 and 2, a circuit component 23, that is, a circuit component including a displacement detecting output circuit, a correction displacement output circuit, and a differential circuit, is further provided on the second substrate 22.

When the common electrode 100 is charged, the charge can be induced on each of the detecting electrode 201 and the correcting electrode 202. It is assumed that the induced charge on the detecting electrode 201 is Q201, and the induced charge on the correcting electrode is Q202. At this time, the displacement output circuit is detected. The voltage output signal is V201,

The voltage output signal of the correction displacement output circuit is V202.

Wherein C201 and C202 are capacitance capacities of the detecting electrode 201 and the correcting electrode 202, and the capacitance of the detecting electrode 201 and the correcting electrode 202 should be C201=C202=C when the electrodes are disposed. The output of such a differential circuit

G is the magnification of differential amplification.

The amount of charge induced on the detecting electrode 201 and the correcting electrode 202 depends on the area of the electrode and the distance between the two electrodes from the common electrode 100, the amount of charge carried on the common electrode 100, and the relationship between the two electrodes and the common electrode 100. Dielectric constant. In the case where the structure is constant, the amount of charge induced on the detecting electrode 201 and the correcting electrode 202 is only related to the dielectric constant between the detecting electrode 201, the correcting electrode 202, and the common electrode 100. When the object to be detected passes through the detection channel, the dielectric constant of the medium between the detecting electrode 201 and the common electrode 100 is changed, and the amount of charge induced on the detecting electrode 201 is changed. Assuming that the amount of charge change is a, the displacement output is detected at this time. Circuit voltage output

When the object to be detected passes through the detection channel, since the correction electrode 202 is located outside the effective detection range, the dielectric constant of the medium between the correction electrode 202 and the common electrode 100 does not change, and the amount of charge induced on the correction electrode 202 is also The voltage output of the correction displacement output circuit does not change, and the voltage output of the displacement output circuit is corrected.

C201=C202=C. Differential circuit output

It can be calculated that when the film to be tested passes, the change in the charge of the detecting electrode 201 is

Therefore, the thickness of the film to be tested can be calculated by the change in the amount of charge on the electrode.

In the case of temperature, humidity change and noise influence, the sensitivity of the correction electrode 202 is the same as that of the detection electrode 201, and the same effect is felt on the detection electrode 201 and the correction electrode 202, and the amount of charge change is also the same, assuming a change in charge due to external disturbance. The quantity is b, at this time, the voltage output of the displacement output circuit is detected.

Correct the voltage output of the displacement output circuit

C201=C202=C. Differential circuit output

It is possible to calculate the change in the charge of the detecting electrode 201 when the object to be detected passes when the temperature, the humidity change, and the noise are affected.

This value is the same as the calculated value without the influence of temperature, humidity and noise. Therefore, the correction electrode 202 and the differential circuit can eliminate the influence of the temperature, humidity and noise of the detecting electrode 201, and ensure the accuracy of the thickness detection.

It should be noted that, in the embodiment shown in FIG. 1 , the thickness detecting device further includes: a first substrate 12 and a second substrate 22 , the common electrode 100 is disposed on the first substrate 12 , and the detecting electrode 201 and the correcting electrode 202 It is disposed on the second substrate 22. The thickness detecting device further includes: a first frame 11 and a second frame 21, wherein the first substrate 12 is disposed on the first frame 11; the second frame 21 is spaced apart from the first frame 11, the second substrate 22 is disposed on the second housing 21.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A thickness detecting device, comprising:

Common electrode (100);

The detecting electrodes (201) are disposed corresponding to the common electrode (100) and spaced apart from each other, and a detecting channel is formed between the detecting electrode (201) and the common electrode (100);

a correction electrode (202) corresponding to the common electrode (100) and spaced apart from each other, the correction electrode (202) being disposed outside the detection channel;

a control unit electrically connected to the common electrode (100), the detecting electrode (201), and the correction electrode (202) for the detection electrode (201) according to an output of the correction electrode (202) The output of the ) is corrected.
The thickness detecting device according to claim 1, wherein an electrical characteristic formed between the correction electrode (202) and the common electrode (100) and the detecting electrode (201) and the common electrode ( The electrical characteristics formed between 100) are the same.
The thickness detecting device according to claim 1, wherein the correction electrode (202) has the same size as the detection electrode (201), and the correction electrode (202) and the common electrode (100) The distance between the intervals is equal to the distance between the detecting electrode (201) and the common electrode (100).
The thickness detecting device according to claim 1, wherein the correction electrode (202) is disposed apart from the detecting electrode (201) in a direction perpendicular to an extending direction of the detecting channel.
The thickness detecting device according to claim 1, wherein the detecting electrodes (201) are plural, and the plurality of detecting electrodes (201) are arranged side by side, and the detecting channel extends in a plurality of directions. The arrangement direction of the electrodes (201) is detected.
The thickness detecting device according to claim 1, wherein the thickness detecting device further comprises a first protecting portion (14) disposed outside the common electrode (100), and/or disposed at the detecting electrode (201) The second protective portion (24) on the outer side.
The thickness detecting device according to claim 1, wherein the thickness detecting device further comprises a second protecting portion (24) disposed outside the detecting electrode (201) and disposed at the correcting electrode (202) a third third protecting portion covering a thickness of the second protecting portion (24) on an outer surface of the detecting electrode (201) facing the common electrode (100) and covering the correcting electrode (202) The thickness of the third protection portion on the outer surface of the common electrode (100) is equal.
The thickness detecting device according to claim 1, wherein the thickness detecting device further comprises:

a first conductive portion (15) disposed on an outer surface of the common electrode (100) facing the detecting electrode (201);

a second conductive portion (25) disposed on an outer surface of the detecting electrode (201) facing the common electrode (100);

a third conductive portion (26) disposed on an outer surface of the correction electrode (202) facing the common electrode (100);

The second conductive portion (25) is the same size as the third conductive portion (26).
The thickness detecting device according to claim 1, wherein the control portion includes a differential circuit, and an input end of the differential circuit is electrically connected to the detecting electrode (201) and the correcting electrode (202), respectively. The difference circuit obtains an output value based on a difference between an output of the detecting electrode (201) and an output of the correcting electrode (202).
The thickness detecting device according to claim 1, wherein the control portion comprises:

Detecting a displacement output circuit, the input end is electrically connected to the detecting electrode (201), and is configured to output an electrical signal generated between the detecting electrode (201) and the common electrode (100);

A correction displacement output circuit is electrically connected to the correction electrode (202) for outputting an electrical signal generated between the correction electrode (202) and the common electrode (100).