Transmitter

Abstract

A transmitter is disclosed. In one embodiment, the transmitter comprises: a housing having an opening; a cover disposed at the opening of the housing, the cover including a conductive panel; a diaphragm adjacent to the cover within the housing, the diaphragm including at least one aperture below the conductive panel; a circuit board adjacent to the diaphragm within the housing, the circuit board including at least one coil, each of the at least one coil being located below a respective one of the at least one apertures; the functional board is arranged in the shell; a microprocessor and an inductance digital converter electrically connected with the microprocessor and the at least one coil are arranged on the functional board; wherein the inductance-to-digital converter is configured to, in response to a press on a corresponding local area of the conductive panel above one of the at least one aperture, generate a touch signal indicative of the press, and output the touch signal to the microprocessor.

Description

Technical Field

[0001] The present disclosure relates generally to signal measurement and, more particularly, to a transmitter including an inductance-dependent touch button. Background Art

[0002] The transmitter is a converter that converts the output signal of the sensor into a signal that can be recognized by the controller.

[0003] The transmitter can be used for a flow meter. For example, a flow meter for measuring fluid flow may include a measuring tube, a sensor and a transmitter. Exemplarily, such a transmitter includes a housing having an opening, a cover arranged at the opening of the housing, a display module arranged in the housing, a function board with a microprocessor arranged in the housing, and a core processing module. The core processing module sends a drive signal for driving the sensor; the core processing module also receives an analog signal generated by the sensor in response to the movement of the coil; the core processing module converts the analog signal into a digital signal and provides it to the function board. The microprocessor on the function board can process the received digital signal and provide a display signal to the display module. The display module includes, for example, a display unit such as a liquid crystal display screen. The display unit displays information to the user based on the display signal, for example, the current flow rate. There is a panel in the central area of ​​the cover, and the panel may include a button area and a transparent area. The transparent area enables the user to see the display screen below. The button area is configured in an area corresponding to the peripheral area of ​​the display screen. The button is used for the user to interact with the transmitter. The button is, for example, a capacitive touch button. The capacitive touch button is, for example, a metal capacitive touch button. The typical structure of a metal capacitive touch button includes: a conductive metal cover layer (i.e., a conductive cover layer that acts as an upper electrode), a gap, and a metal capacitive touch sensor (i.e., a lower electrode). This structure forms a capacitor. When a finger presses the conductive metal cover layer, the conductive metal cover layer is deformed, and the distance between the deformed conductive metal cover layer and the metal capacitive touch sensor is reduced, so that the capacitance changes. The conductive metal cover layer can be formed on the panel of the cover. There are a partition and a circuit board under the panel. The partition has a hole. The circuit board is provided with a lower electrode at a position corresponding to the hole of the partition. That is, the hole of the partition is used to form a gap between the conductive metal cover layer and the lower electrode. The position of the touch button has been identified, so when the user touches the identification area corresponding to the touch button on the panel, an output signal indicating touch can be generated based on the capacitance change, and the function board performs a corresponding function based on the output signal, thereby realizing the interaction between the user and the transmitter.

[0004] The conductive metal cover layer of the above-mentioned metal capacitive touch button is relatively thin, and the conductive cover layer needs to be grounded, which may limit its application. Such metal capacitive touch button is not ideal in terms of anti-electromagnetic interference and electromagnetic compatibility. Summary of the invention

[0005] A brief summary of the present disclosure will be given below to provide a basic understanding of some aspects of the present disclosure. It should be understood that this summary is not an exhaustive summary of the present disclosure. The following summary is not intended to determine the key or important parts of the present disclosure, nor is it intended to limit the scope of the present disclosure. Its purpose is simply to provide certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] According to one aspect of the present disclosure, a transmitter is provided. The transmitter includes: a housing having an opening; a cover arranged at the opening of the housing, the cover including a conductive panel; a partition adjacent to the cover in the housing, the partition including at least one hole located below the conductive panel; a circuit board adjacent to the partition in the housing, the circuit board including at least one coil, each of the at least one coil being located below a corresponding hole in at least one hole; and a function board in the housing, a microprocessor and an inductance digital converter electrically connected to the microprocessor and the at least one coil being arranged on the function board; wherein the inductance digital converter is configured to: in response to pressing a corresponding local area of ​​the conductive panel above one of the at least one holes, generate a touch signal indicating the pressing, and output the touch signal to the microprocessor

[0007] The beneficial technical effects of the technical solution of the present disclosure include at least one of the following: eliminating the grounding requirement of the conductive cover layer of the touch button of the transmitter, and improving the performance of the touch button in terms of anti-electromagnetic interference and electromagnetic compatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The disclosure may be better understood by reference to the following description given in conjunction with the accompanying drawings, wherein like reference numerals represent like components. It should be understood that the drawings are not necessarily drawn to scale. In the drawings:

[0009] Figure 1 An exploded view showing a schematic structure of a transmitter according to an embodiment of the present disclosure;

[0010] Figure 2 shows a touch button before being pressed according to one embodiment of the present disclosure;

[0011] Figure 3 shows a touch button after being pressed according to one embodiment of the present disclosure;

[0012] Figure 4 An equivalent circuit of a touch button according to an embodiment of the present disclosure is shown;

[0013] Figure 5 shows a touch signal provided by an LDC according to an embodiment of the present disclosure; and

[0014] Figure 6 A touch sensing circuit of a transmitter according to one embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0015] Exemplary embodiments of the present disclosure are described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of actual embodiments are described in the specification. However, it should be understood that many implementation-specific decisions may be made in the process of developing any such actual embodiments in order to achieve the specific goals of the developer, and these decisions may vary from implementation to implementation.

[0016] It should also be noted here that in order to avoid obscuring the present disclosure due to unnecessary details, only the device structure closely related to the scheme according to the present disclosure is shown in the drawings, while other details that are not closely related to the present disclosure are omitted.

[0017] One aspect of the present disclosure discloses a transmitter. Figure 1 This transmitter is described as an example.

[0018] Figure 1 An exploded view of a schematic structure of a transmitter 10 according to an embodiment of the present disclosure is shown. The transmitter 10 includes: a housing 11, a cover 13, a partition 15, a circuit board 17, and a functional board 19. The housing 11 has an opening. The opening is suitable for assembling the cover 13 with the housing 11. The cover 13 is arranged at the opening of the housing 11. The cover 13 includes a conductive panel 131. The partition 15 is arranged adjacent to the cover 13 in the housing 11. The partition 15 includes at least one hole, such as a hole 151, located below the conductive panel 131. The circuit board 17 is adjacent to the partition 15 in the housing 11. The circuit board 17 includes at least one coil, such as a coil 171. Each of the at least one coil is located below a corresponding hole in the at least one hole. For example, the coil 171 is below the hole 151. Preferably, the center position of the coil 171 is aligned with the center of the hole 151. The functional board 19 is in the housing 11. A microprocessor 193 and an inductance-to-digital converter (LDC) 191 electrically connected to the microprocessor 193 and at least one coil are arranged on the function board 19. The inductance-to-digital converter 191 is configured to generate a touch signal indicating the pressing in response to pressing of a corresponding local area of ​​the conductive panel above one of the at least one holes, and output the touch signal to the microprocessor 193. Figure 1 The components of the transmitter 10 shown in FIG. 1 are merely exemplary, and the transmitter 10 may further include other components such as a display module, a connecting component, and the like.

[0019] The cover 13 may include an opening 135 in the central area and a conductive panel 131 surrounding the opening. The conductive panel 131 includes an aluminum layer, a stainless steel layer or a transparent indium tin oxide layer. For example, the conductive panel 131 is 2 mm thick stainless steel. The opening 135 of the cover 13 can be used to view the information displayed on the display screen of the display module. The opening may be inlaid with a transparent cover plate. The conductive panel 131 preferably includes an aluminum layer or a stainless steel layer. Stainless steel and aluminum have a higher lift-off effect, and when they are pressed close to the coil below, stronger eddy currents can be generated, which is conducive to higher touch sensing sensitivity. Therefore, the conductive panel 131 preferably includes an aluminum layer and a stainless steel layer.

[0020] The partition 15 may be made of insulating material, have an opening in the center, or include a plurality of holes. Figure 1 Four holes are schematically shown, which are symmetrically distributed around the opening of the partition 15. The size of the hole can be determined with reference to the two-dimensional size of the coil below it on the surface of the circuit board. For example, the size of the hole is larger than the two-dimensional size of the coil below it, or is substantially the same, wherein the two-dimensional size is the maximum width of the geometric projection figure of the coil on the surface of the circuit board. For example, the hole is a circle with a diameter of Du, the geometric projection figure is a spiral, and its maximum width is Dc, Du:Dc is in the range of 1.5 to 1.0, preferably, Du:Dc is in the range of 1.5 to 1.1. The shape of the coil includes, but is not limited to: circle (the outline of the spiral is regarded as a circle), ellipse and rectangle. The rectangle is preferably a square. The number of holes is, for example, 1, 2, 3, 4, 5, 6 or more. Each hole corresponds to a touch button. The partition 15 preferably has a thickness of 1.0 mm to 6.0 mm to obtain an ideal touch sensing sensitivity.

[0021] The number of coils included in the circuit board 17 is the same as the number of holes of the partition 15 above it. And, preferably, the position of each coil is aligned with the center position of the corresponding hole. The circuit board 17 has an opening in the center. The circuit board 17 can be a printed circuit board. The coil can be formed by patterning the metal layer on the circuit board. It should be noted that in the assembled state, the conductive panel 131, the partition 15 and the circuit board 17 are arranged in pairs, wherein the partition 15 is between the conductive panel 131 and the circuit board 17.

[0022] Above each hole of the partition 15, the corresponding local area of ​​the conductive panel 131 is marked so that the user can identify the position of each touch button, thereby selecting a predetermined button and operating it accurately. For example, the local area 133 of the conductive panel 131 above the hole 151 is marked to facilitate accurate operation by the user. The conductive touch area in the local area 133 of the conductive panel 131, the hole 151, and the coil 171 constitute an example touch button of the present disclosure.

[0023] Based on the above description, it can be known that the transmitter of the present disclosure includes a touch button based on an inductor coil, wherein the inductor coil connected to an inductance digital converter acts as a touch sensor. The inductance digital converter is used to generate a touch signal.

[0024] You can refer to Figure 2 and Figure 3 Understand the changes of the touch button of the present disclosure before and after being touched. Figure 2 The touch button 20 is shown before being pressed according to one embodiment of the present disclosure. Figure 3 FIG. 2 shows a touch button 20 after being pressed according to one embodiment of the present disclosure. Figure 2 As shown in , when the components of the transmitter are assembled, the conductive panel 131, the partition 15 and the circuit board 17 are arranged in pairs, wherein the partition 15 is between the conductive panel 131 and the circuit board 17. The space corresponding to the hole 151 of the partition 15 serves as the gap between the conductive touch area of ​​the touch button 20 and the coil 171 on the circuit board 17. Figure 3 As shown in , after touching the conductive panel 131 (for example, pressing with a finger), the corresponding partial panel of the conductive panel 131 is deformed, and the distribution of the distance between the partial panel and the coil 171 changes. If a capacitor is connected in parallel to the coil 171 and electric energy is applied, LC oscillation may occur. The distribution change of the distance may affect the characteristics of the LC oscillation. Thus, the inductance digital converter may be used to detect the touch based on the characteristics of the LC oscillation.

[0025] The principle of touch detection will be described below with reference to an equivalent circuit of a touch button of the present disclosure. Figure 4 An equivalent circuit 40 of a touch button according to an embodiment of the present disclosure is shown, which includes an inductor and a capacitor that constitute an LC oscillation circuit. The inductance L(d) is the sum of the inductance Ls and the inductance Lu of the coil, wherein Lu is the coupling inductance between the coil and the conductive panel, the coupling inductance Lu is related to the distance d between the conductive panel and the coil, C is the capacitance of the capacitor in parallel with the coil, Sd is the AC drive signal applied to the coil, and Rp(d) is the parallel equivalent resonant impedance, which is related to the parasitic resistance Rs of the coil, the eddy current parasitic resistance R(d) of the conductive panel, the capacitance C and the inductance L(d). The parallel equivalent resonant impedance Rp(d) is related to the distance d, and Rp(d) increases as the distance d increases. The AC drive signal Sd will generate a changing magnetic field, thereby generating eddy currents on the surface of the conductive panel. That is, the conductive panel and the coil are electromagnetically coupled. This coupling is related to the distance d. The applied electrical energy causes LC oscillation, and the oscillation frequency is related to the inductance L(d). That is, the oscillation frequency is related to the distance d. Thus, touch can be detected based on the oscillation frequency. LDC can be used to implement this touch detection based on LC oscillation. LDC can measure the parallel equivalent resonant impedance Rp(d) and the resonant frequency. In order to suppress the interference caused by the parasitic capacitance formed between the local panel and the corresponding coil, the capacitance of the capacitor in parallel with the coil is preferably between 100pF and 1nF. Exemplary parameters of the coil are as follows: diameter 14mm, 23 turns, line width of 4mil, adjacent line spacing 4mil, material is copper, line thickness 1oz (obtained by patterned etching of 1oz thick copper foil on FR4 circuit board).

[0026] Figure 5 FIG. 1 shows a touch signal provided by an LDC according to an embodiment of the present disclosure. In the case where an inductance digital converter LDC is used to connect three touch sensors according to an embodiment of the present disclosure, as shown in FIG. Figure 5 As shown in Figure 2, three measurement results are generated: 1 (t),Measure 2 (t),Measure 3 (t). The intensity I of the signal output by the LDC is used to determine whether a touch occurs, wherein the intensity I is related to the frequency of the LC oscillation. When the touch sensor is driven by an AC drive signal, the intensity I of the signal output by the LDC will increase significantly after a touch occurs, so that the occurrence of a touch can be detected by using this characteristic. The LDC is, for example, the LDC1614RGH chip of Texas Instruments.

[0027] Figure 6 FIG. 6 shows a touch sensing circuit 60 of a transmitter according to one embodiment of the present disclosure. Figure 6 As shown in , the transmitter is configured with 4 coils: Coil1, Coil2, Coil3 and Coil4 to provide 4 touch buttons for the transmitter. The 4 coils are arranged on a circuit board. A capacitor is also configured for each coil on the circuit board. Figure 6As shown in , coil Coil1 is connected in parallel with capacitor C25, and the nominal capacitance of capacitor C25 is, for example, 100pF; coil Coil2 is connected in parallel with capacitor C28, and the nominal capacitance of capacitor C28 is, for example, 120pF; coil Coil3 is connected in parallel with capacitor C30, and the nominal capacitance of capacitor C30 is, for example, 120pF; coil Coil4 is connected in parallel with capacitor C31, and the nominal capacitance of capacitor C31 is, for example, 100pF. Each of the four coils is connected to two corresponding ports of the inductance digital converter U7 via two parallel nodes connected to the corresponding capacitors. The inductance digital converter U7 is, for example, an LDC1614RGH chip. The inductance digital converter U7 outputs a touch signal from ports B1_SDA and B1_SCL to the microprocessor via the I2C bus. The microprocessor is, for example, an MSP430 processor. The inductance digital converter U7 is connected to a DC power supply E via a power input terminal VDD and a magnetic bead L6. The power input terminal VDD is connected to a ground (“GND” represents “ground”) via a grounding capacitor. Figure 6 In the example, two capacitors C26 and C27 are grounded via the power input terminal VDD. Those skilled in the art will appreciate that one equivalent capacitor may also be used.

[0028] For the solution disclosed in the present disclosure, by using an inductance-to-digital converter to detect touch based on inductance, compared with conventional metal capacitive touch buttons, the grounding requirement of the conductive panel of the touch button is eliminated, and the performance of the touch button in terms of anti-electromagnetic interference and electromagnetic compatibility is improved. At the same time, the conductive panel can be designed to be thicker, which has corresponding advantages in practical applications.

[0029] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements or components, but does not exclude the presence or addition of one or more other features, elements or components.

[0030] Although the present disclosure has been disclosed above by describing the specific embodiments of the present disclosure, it should be understood that those skilled in the art can design various modifications, improvements or equivalents to the present disclosure within the spirit and scope of the appended claims. These modifications, improvements or equivalents should also be considered to be included in the protection scope of the present disclosure.

Claims

1. A transmitter, characterized in that: include: a housing having an opening; a cover disposed at the opening of the housing, the cover comprising a conductive panel; a partition within the housing adjacent the cover, the partition including at least one aperture below the conductive panel; a circuit board within the housing adjacent the partition, the circuit board including at least one coil, each of the at least one coil being positioned below a corresponding one of the at least one aperture; as well as a function board in the housing, wherein a microprocessor and an inductance-to-digital converter electrically connected to the microprocessor and the at least one coil are arranged on the function board; The inductance digital converter is configured to: in response to pressing a corresponding local area of ​​the conductive panel above one of the at least one holes, generate a touch signal indicating the pressing, and output the touch signal to the microprocessor.

2. The transmitter according to claim 1, wherein: The conductive panel includes an aluminum layer, a stainless steel layer or a transparent indium tin oxide layer.

3. The transmitter according to claim 1, wherein: The number of the at least one coil is equal to or greater than two.

4. The transmitter according to claim 1, wherein: A corresponding local area above each of the at least one hole of the conductive panel is identified as a touch button.

5. The transmitter according to claim 1, wherein: The inductance digital converter is connected to a power supply via a power input terminal and a magnetic bead; and The power input terminal is grounded via a grounding capacitor.

6. The transmitter according to claim 1, wherein: The inductance-to-digital converter is configured to output the touch signal to the microprocessor via an I2C bus.

7. The transmitter according to claim 1, wherein: The circuit board also includes a respective capacitor connected in parallel with each of the at least one coil; and Each of the at least one coil is connected to two respective ports of the inductance-to-digital converter via two parallel nodes connected to the respective capacitors.

8. The transmitter according to claim 7, wherein: The capacitance of the corresponding capacitor is 100 pF to 1 nF.

9. The transmitter according to claim 1, wherein: The inductance-to-digital converter is configured to generate the touch signal related to an LC resonant frequency.

10. The transmitter according to claim 1, wherein: The separator has a thickness of 1.0 mm to 6.0 mm.

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