WO2020073170A1

WO2020073170A1 - Key device and operation panel

Info

Publication number: WO2020073170A1
Application number: PCT/CN2018/109350
Authority: WO
Inventors: Ming Chun Wu; Rui Xing CHAI; Ying Han; Hai Bao NAN
Original assignee: Siemens Aktiengesellschaft
Priority date: 2018-10-08
Filing date: 2018-10-08
Publication date: 2020-04-16

Abstract

A key device(10), including: a sensing portion (12), which includes a magnetic core (121) and an induction coil (122) wound around the magnetic core (121); and a pressing portion(14), where the pressing portion(14) and the sensing portion(12) are disposed opposite to each other. The pressing portion(14) includes a body and a metal piece(141) disposed on a first surface of the body, and a gap exists between the metal piece (141) and the sensing portion (12). When the pressing portion (14) drives the metal piece(141) to move relative to the sensing portion (12) under an external force, the sensing portion (12) generates a first signal under an eddy current effect.

Description

KEY DEVICE AND OPERATION PANEL

BACKGROUND Technical Field

The present invention relates to the field of industry, and in particular, to a contactless key device and an operation panel.

Related Art

As an important human-computer interaction tool for a control system, keys and operation panels play an important role in the field of industrial control. Their reliability directly determines the stability of system operation. At present, the operation panel with mechanical contact keys is commonly used in the field of industrial control. The mechanical contact key has a mature processing technology, but the application environment of the industrial control system is relatively harsh, usually a production room. There are many gaps around the mechanical contact key, resulting in a low waterproof and dustproof level, and the key is easy to be stuck by surrounding mechanical devices or dust particles and the water is easy to enter the key structure. Moreover, due to a long-term mechanical force of variable load, the mechanical contact key has a short life and poor reliability. A capacitive key that emerges recently is based on an electrical principle: when a human body touches an electrode, a sensor detects a changed capacitance, then converts the capacitance into a voltage signal through a chip, and then transmits the voltage signal to a chip to realize the key function. However, the capacitive key may be greatly affected by external interference (for example, temperature and humidity) , which is easy to cause false touches, and an operator cannot operate the key while wearing gloves. In addition, the above two types of keys must be operated in a contact manner, which will bring about certain wear and aging problems.

SUMMARY

In view of the above problems in the prior art, the present invention provides a contactless induction key which has a long service life and high reliability, and an operation panel.

According to one aspect of the present invention, a key device is provided. The key device includes: a sensing portion, including a magnetic core and an induction coil wound around the magnetic core; and a pressing portion, where the pressing portion and the sensing portion are disposed opposite to each other. The pressing portion includes a body and a metal piece disposed on a first surface of the body, and a gap exists between the metal piece and the sensing portion. When the pressing portion drives the metal piece to move relative to the sensing portion under an external force, the sensing portion generates a first signal under an eddy current effect.

According to an embodiment, the body of the pressing portion is a plastic panel, and the body of the pressing portion and the metal piece are integrally formed by injection molding.

According to an embodiment, the pressing portion further includes: a key area, arranged on a second surface of the body of the pressing portion, where the key area corresponds to a position and a size of the sensing portion.

According to an embodiment, the metal piece is a thin aluminum piece.

According to an embodiment, a gap distance between the metal piece and the induction coil is 1/4 to 1/2 of a diameter of the induction coil.

According to an embodiment, the first signal includes: an inductance change amount and/or an impedance change amount of the sensing portion.

According to an embodiment, the key device further includes: a detection portion, where the detection portion is connected to the sensing portion and receives the first signal from the sensing portion to detect a pressing state of the pressing portion.

According to an embodiment, the detection portion includes a capacitor, an inductive sensing chip, and an MCU. The capacitor is connected in parallel with the sensing portion, where the inductive sensing chip outputs a second signal to the sensing portion to cause the sensing portion to generate a high-frequency magnetic field, and the inductive sensing chip is capable of converting the received first signal into a digital signal and transmitting the digital signal to the MCU.

According to an embodiment, the inductive sensing chip is an LDC1314 integrated chip having four measurement channels.

According to still another aspect of the present invention, an operation panel is provided. The operation panel includes: a panel, a circuit board disposed on the back of the panel, and at least one key device, where the key device includes: a sensing portion disposed on the circuit board. The sensing portion includes a magnetic core and an induction coil wound around the magnetic core, and a pressing portion disposed on the panel. The pressing portion and the sensing portion are disposed opposite to each other. The pressing portion includes a body and a metal piece. The metal piece is disposed on an end surface of the body near the circuit board, and a gap exists between the metal piece and the sensing portion. When the pressing portion drives the metal piece to move relative to the sensing portion under an external force, the sensing portion generates a first signal under an eddy current effect.

According to an embodiment, the circuit board is provided with a mounting hole adapted to accommodate the magnetic core, and a size of the mounting hole matches the magnetic core.

According to an embodiment, the magnetic core is fixed in the mounting hole by using an assembly method of glue dispensing.

According to an embodiment, the magnetic core is cylindrical, and a height of the magnetic core is greater than or equal to a thickness of the circuit board.

According to an embodiment, the mounting hole is a through hole penetrating the circuit board, and a first end of the magnetic core is flush with an upper surface of the circuit board. The operation panel further includes: a holder, where a circular groove is provided on the holder. The circular groove is adapted to accommodate a second end of the magnetic core, and the holder abuts against the second end of the magnetic core protruding from a lower surface of the circuit board.

According to an embodiment, the induction coil is closely attached on a surface of the circuit board, and is wound around the magnetic core in a plane where the circuit board is located to form a spiral planar coil.

According to an embodiment, the pressing portion further includes: a key area, arranged on an outer surface of the panel, where the key area corresponds to a position and a size of the sensing portion.

It should be understood that the foregoing general descriptions and the following detailed descriptions are all exemplary and illustrative, and aim to further explain the present invention defined by the appending claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings provide further understanding of the present invention, and they are included and constitute one part of the present invention. The accompanying drawings show embodiments of the present invention and explain the principles of the present invention together with the specification. In the accompanying drawings:

FIG. 1 is a key device and an operation panel according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a key device according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a key device according to another embodiment of the present invention; and

FIG. 4 is a partially cross-sectional view of an operation panel according to another embodiment of the present invention.

DETAILED DESCRIPTION

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. References are made in detail to the preferred embodiments of the present invention, and examples of the preferred embodiments are shown in the accompanying drawings. Whenever possible, the same reference numerals are used in all the accompanying drawings to represent the same or similar parts. Further, although the terms used in the present invention are selected from well-known public terms, some of the terms mentioned in the specification of the present invention may be selected by the applicant according to his or her judgment, and the detailed meanings thereof are described in the relevant parts of the specification. In addition, it is intended that the present invention is understood not only based on the actual terms that are used, but also based on the meaning of each term.

The basic principles and preferred embodiments of the present invention are discussed in more detail with reference to FIG. 1 and FIG. 2. A key device 10 according to the present invention mainly includes: a sensing portion 12 and a pressing portion 14. The sensing portion 12 and the pressing portion 14 are disposed opposite to each other and a gap exists between the sensing portion 12 and the pressing portion 14. When a relative movement occurs between the pressing portion 14 and the sensing portion 12, the sensing portion 12 generates a first signal under an eddy current effect. According to an implementation, even if the pressing portion 14 is pressed and moves toward the sensing portion 12, the sensing portion 12 does not contact the pressing portion, thereby avoiding mechanical collision and reducing key wear, and achieving contactless detection of a key. The sensing portion 12 mainly includes a magnetic core 121 located at the center and an induction coil 122 wound around the magnetic core 121. By means of disposing the magnetic core 121 in the middle of the induction coil 122, sensitivity of the induction coil 122 can be improved, thereby improving the sensitivity and precision of the key detection. The pressing portion 14 mainly includes a body of the pressing portion and a metal piece 141 disposed on a first surface of the body (for example, a lower surface of the pressing portion 14 in FIG. 2) , that is, the metal piece 141 is fixed on a bottom of the pressing portion 14. When the pressing portion 14 drives the metal piece 141 to move relative to the sensing portion 12 under an external force, the sensing portion 12 generates the first signal under the eddy current effect. Compared with the prior art, the key device 10 has low manufacturing costs, a long service life, and high sensitivity and reliability.

Specifically, in one embodiment, the pressing portion 14 may be, for example, a metal panel. Alternatively, in another embodiment, a body of the pressing portion 14 may be, for example, a plastic panel, and the metal piece 141 is fixed on a surface of the plastic panel near the sensing portion 12. In this embodiment, the body of the pressing portion 14 and the metal piece 141 may be injection molded together in an insertion manner to form an integral structure. The body of the pressing portion 14 is made of a plastic material. The plastic material is low in cost and easy to manufacture, and the plastic panel is more susceptible to deformation than the metal panel, which makes the user's pressing operation easier, greatly improving the user experience. Moreover, an industrial panel commonly requires a thickness up to a certain standard. If the pressing portion 14 is made of a thick metal panel, the pressing portion 14 is difficult to deform under a pressing force, and the user needs to exert a large force to perform operations. However, the plastic material is low in cost and easy to manufacture, and meanwhile is fully capable of meeting industrial requirements, meeting grade IP ratings and manufacturing requirements. The thickness at the pressing portion 14 may range, for example, from 5 mm to 15 mm, and preferably, the thickness at the pressing portion 14 is 10 mm. Further, in a specific embodiment, the metal piece 141 may be, for example, a thin aluminum piece, which is easy to manufacture and low in cost. Moreover, it has been proved in many experiments that the aluminum piece is more sensitive than other metals.

In a preferred embodiment, the pressing portion 14 may further include: a key area 142, arranged on a second surface of the body of the pressing portion 14 (for example, an upper surface of the pressing portion 14 in FIG. 1) . The key area 142 corresponds to a position and a size of the sensing portion 12. Specifically, the pressing area 142 may include a plurality of round button icons, and each round button icon corresponds to a size of the induction coil 122. The round button icons may be disposed on an outer surface of the pressing portion 14, and specific positions may be determined by the projection of the induction coil 122 on the pressing panel in a vertical direction.

As shown in FIG. 2, a gap exists between the metal piece 141 and the induction coil 122, and the gap distance can be set within a certain range. Specifically, the gap may range between, for example, 1/4 to 1/2 of a diameter of the induction coil 122. If the gap between the metal piece 141 and the sensing portion 12 is too narrow, it may cause a collision between the two, and if the gap distance is too wide, the sensitivity of the key may decrease. Many experiments show that when the gap distance between the metal piece 141 and the sensing portion 12 is set to 1/4 to 1/2 of the diameter of the induction coil 122, good sensitivity of the key can be ensured, and meanwhile no contact occurs between the pressing portion 14 and the sensing portion 12 during operation.

In addition, the key device 10 may further include a detection portion 16. The detection portion 16 is connected to the sensing portion 12 and receives the first signal from the sensing portion 12 to detect a pressing state of the pressing portion 14. Using FIG. 3 as an example, the detection portion 16 includes a capacitor 161, an inductive sensing chip 162, and an MCU. The sensing portion 12 can be regarded as an inductance component in a detection circuit, and the capacitor 161 is connected in parallel with the sensing portion 12 to form an LC loop. The capacitor 161 can be, for example, a resonant capacitor to ensure signal integrity. When the inductive sensing chip 162 is in operation, an output pin thereof can output a second signal to the LC loop which contains the sensing portion 12. Here, the second signal can be, for example, a sine-wave signal of a fixed frequency. In a preferred embodiment, the second signal may be, for example, a high frequency excitation signal. Meanwhile, a high-frequency magnetic field is generated correspondingly near the sensing portion 12. The frequency of the LC loop is stable when the pressing portion 14 does not deform. When the pressing portion 14 deforms under a force, the metal piece 141 approaches the sensing portion 12, and in the environment of the high-frequency magnetic field, the inside of the metal piece 141 generates an eddy current due to the eddy current effect. The eddy current of the metal piece 141 generates a new magnetic field, which affects the high-frequency magnetic field near the sensing portion 12, thereby changing an inductance value and impedance of the original LC loop in the stable state. In other words, the metal piece 141 can be driven to move in a vertical direction when the pressing portion 14 is pressed. When the pressing portion 14 drives the metal piece 141 to move relative to the sensing portion 12 under an external force, the sensing portion 12 generates the first signal under the eddy current effect. The first signal includes an inductance change amount and/or an impedance change amount of the sensing portion 12. Then, the inductive sensing chip 162 receives the first signal, converts the first signal into a digital signal, and sends the digital signal to the MCU. That is, the inductive sensing chip 162 can measure the change value of the inductance and impedance in the circuit. When it is detected that the pressing portion 14 deforms, detection information is transmitted to the MCU, and a state of the key is fed back to the MCU to implement the key function. The inductive sensing chip 162 can be, for example, an LDC1314 integrated chip. The LDC1314 is a single-chip integrated inductive sensing chip with four measurement channels, and is connected to the LC loop through the measurement channels. The LDC 1314 can operate after being connected to an external inductor and capacitor.

In a detection circuit, the number of turns of the induction coil 122 and the iron core 121 can both affect an inductance value L of the sensing portion 12. Theoretically, the inductance value L can be calculated by a formula: L = N ²μS /I, where N is the number of turns of the induction coil, and μ is a magnetic permeability. It can be seen that the inductance value L is proportional to the square of the number of turns of the induction coil and is proportional to the magnetic permeability. The magnetic permeability of the sensing portion 12 can be greatly increased by disposing the magnetic core 121 in the middle of the induction coil 122. When the user presses the panel to perform the key operation, the magnetic core 121 can increase the amount of change in an inductive reactance value, thereby improving the sensitivity of the sensing portion 12, and improving the sensitivity during key sensing. Moreover, since the magnetic core 121 is disposed, the number of turns of the induction coil 122 can be appropriately reduced correspondingly. In this case, the key can occupy only a small planar space, which is beneficial to the arrangement of other components on the operation panel.

FIG. 1 is a key device and an operation panel according to an embodiment of the present invention. Using FIG. 1 as an example, the operation panel according to the present invention mainly includes: a panel 20, a circuit board 30 disposed on the back of the panel 20, and at least one key device 10, where the key device 10 includes a sensing portion 12 disposed on the circuit board 30 and a pressing portion 14 disposed on the panel 20. The sensing portion 12 includes a magnetic core 121 and an induction coil 122 wound around the magnetic core 121. The pressing portion 14 and the sensing portion 12 are disposed opposite to each other. The pressing portion 14 includes a body and a metal piece 141. The metal piece 141 is disposed on an end surface of the body near the circuit board 30, and a gap exists between the metal piece 141 and the sensing portion 12. When the pressing portion 14 drives the metal piece 141 to move relative to the sensing portion 12 under an external force, the sensing portion 12 generates a first signal under an eddy current effect.

Specifically, the circuit board 30 is provided with a mounting hole 31 which is adapted to accommodate the magnetic core 121, and a size of the mounting hole 31 matches the magnetic core 121. The magnetic core 121 can be fixed in the mounting hole 31 by using, for example, an assembly method of glue dispensing, which can secure stable and reliable fixing of the magnetic core 121. Using FIG. 3 as an example, the magnetic core 121 may be cylindrical and inserted in the mounting hole 31 of the circuit board 30. The magnetic core 121 fits the mounting hole 31 of the circuit board, which is beneficial to assembly and fixing. A height of the magnetic core 121 may be greater than or equal to a thickness of the circuit board 30. The induction coil 122 is closely attached on a surface of the circuit board 30, and is wound around the magnetic core 121 in a plane where the circuit board 30 is located to form a spiral planar coil. The pressing portion 14 further includes: a key area 142, arranged on an outer surface of the panel 20, where the key area 142 corresponds to a position and a size of the sensing portion 12. Specifically, using FIG. 1 as an example, four independent key icons are arranged on the panel 20. The key area has a good appearance and is practical, and is convenient for the user to operate.

In a specific embodiment, the mounting hole 31 may be a through hole penetrating the circuit board 30, and the first end of the magnetic core 121 is flush with an upper surface of the circuit board. Preferably, using FIG. 4 as an example, a holder 40 may be disposed at the bottom of the circuit board 30, and a circular slot is provided on the holder 40. The circular groove is adapted to accommodate a second end of the magnetic core 121, and the holder 40 abuts against the second end of the magnetic core 121 protruding from a lower surface of the circuit board 30. When a height of the magnetic core 121 is greater than a thickness of the circuit board 30, a portion of the magnetic core 121 protrudes from a bottom end of the circuit board 30 to form the second end of the magnetic core 121. At this time, the magnetic core 121 can be fixed by using the holder 40, so that the key device 10 is more shock-resistant, and the reliability of the key device 10 is improved.

Obviously, persons skilled in the art can make various modifications and variations to the foregoing exemplary embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, it is intended that the present invention covers these modifications and variations to the present invention that fall within the scope of protection defined by the appended claims and their equivalent technical solutions.

Claims

A key device (10) , comprising:

a sensing portion (12) , comprising a magnetic core (121) and an induction coil (122) wound around the magnetic core (121) ; and

a pressing portion (14) , wherein the pressing portion (14) and the sensing portion (12) are disposed opposite to each other; the pressing portion (14) comprises a body and a metal piece (141) disposed on a first surface of the body, and a gap exists between the metal piece (141) and the sensing portion (12) ; when the pressing portion (14) drives the metal piece (141) to move relative to the sensing portion (12) under an external force, the sensing portion (12) generates a first signal under an eddy current effect.
The key device (10) according to claim 1, wherein the body of the pressing portion (14) is a plastic panel, and the body of the pressing portion (14) and the metal piece (141) are integrally formed by injection molding.
The key device (10) according to claim 1, wherein the pressing portion (14) further comprises:

a key area (142) , arranged on a second surface of the body of the pressing portion (14) , wherein the key area (142) corresponds to a position and a size of the sensing portion (12) .
The key device (10) according to claim 1, wherein the metal piece (141) is a thin aluminum piece.
The key device (10) according to claim 1, wherein a gap distance between the metal piece (141) and the induction coil (122) is 1/4 to 1/2 of a diameter of the induction coil (122) .
The key device (10) according to claim 1, wherein the first signal comprises: an inductance change amount and/or an impedance change amount of the sensing portion (12) .
The key device (10) according to claim 1, further comprising: a detection portion (16) , wherein the detection portion (16) is connected to the sensing portion (12) and receives the first signal from the sensing portion (12) to detect a pressing state of the pressing portion (14) .
The key device (10) according to claim 7, wherein the detection portion (16) comprises a capacitor (161) , an inductive sensing chip (162) , and an MCU, and the capacitor (161) is connected in parallel with the sensing portion (12) , wherein the inductive sensing chip (162) outputs a second signal to the sensing portion (12) to cause the sensing portion (12) to generate a high-frequency magnetic field, and the inductive sensing chip (162) is capable of converting the received first signal into a digital signal and transmitting the digital signal to the MCU.
The key device (10) according to claim 8, wherein the inductive sensing chip (162) is an LDC1314 integrated chip having four measurement channels.
An operation panel, comprising:

a panel (20) , a circuit board (30) disposed on the back of the panel (20) , and at least one key device (10) , wherein the key device (10) comprises:

a sensing portion (12) disposed on the circuit board (30) , wherein the sensing portion (12) comprises a magnetic core (121) and an induction coil (122) wound around the magnetic core (121) ; and

a pressing portion (14) disposed on the panel (20) , wherein the pressing portion (14) and the sensing portion (12) are disposed opposite to each other; the pressing portion (14) comprises a body and a metal piece (141) ; the metal piece (141) is disposed on an end surface of the body near the circuit board (30) , and a gap exists between the metal piece (141) and the sensing portion (12) ; when the pressing portion (14) drives the metal piece (141) to move relative to the sensing portion (12) under an external force, the sensing portion (12) generates a first signal under an eddy current effect.
The operation panel according to claim 10, wherein the circuit board (30) is provided with a mounting hole (31) adapted to accommodate the magnetic core (121) , and a size of the mounting hole (31) matches the magnetic core (121) .
The operation panel according to claim 11, wherein the magnetic core (121) is fixed in the mounting hole (31) by using an assembly method of glue dispensing.
The operation panel according to claim 10, wherein the magnetic core (121) is cylindrical, and a height of the magnetic core (121) is greater than or equal to a thickness of the circuit board (30) .
The operation panel according to claim 11, wherein the mounting hole (31) is a through hole penetrating the circuit board (30) , a first end of the magnetic core (121) is flush with an upper surface of the circuit board, and the operation panel further comprises:

a holder (40) , wherein a circular groove is provided on the holder (40) ; the circular groove is adapted to accommodate a second end of the magnetic core (121) , and the holder (40) abuts against the second end of the magnetic core (121) protruding from a lower surface of the circuit board (30) .
The operation panel according to claim 10, wherein the induction coil (122) is closely attached on a surface of the circuit board (30) , and is wound around the magnetic core (121) in a plane where the circuit board (30) is located to form a spiral planar coil.
The operation panel according to claim 10, wherein a gap distance between the metal piece (141) and the induction coil (122) is 1/4 to 1/2 of a diameter of the induction coil (122) .
The operation panel according to claim 10, wherein the body of the pressing portion (14) is a plastic panel, and the body of the pressing portion (14) and the metal piece (141) are integrally formed by injection molding.
The operation panel according to claim 10, wherein the pressing portion (14) further comprises:

a key area (142) , arranged on an outer surface of the panel (20) , wherein the key area (142) corresponds to a position and a size of the sensing portion (12) .
The operation panel according to claim 10, wherein the first signal comprises: an inductance change amount and/or an impedance change amount of the sensing portion (12) .
The operation panel according to claim 10, wherein the key device (10) further comprises: a detection portion (16) , wherein the detecting (16) is connected to the sensing portion (12) and receives the first signal from the sensing portion (12) to detect a pressing state of the pressing portion (14) .