Electrostatic positive and negative pressure difference driven micro-electromechanical device and driving method thereof

Abstract

The present invention provides a microelectromechanical device driven by electrostatic positive and negative voltage differences and a driving method thereof. The device includes a first plate and a second plate; the first plate is provided with a first working electrode and a second working electrode arranged along a first dimension, and the second plate is provided with a reference electrode. Furthermore, the microelectromechanical device obtains a first output power supply and a second output power supply, which can be selectively output to the first working electrode, the second working electrode, or the reference electrode; wherein one of the first output power supply and the second output power supply is a DC positive voltage, and the other of the first output power supply and the second output power supply is a DC negative voltage. The present invention also provides a driving method for the aforementioned microelectromechanical device. The present invention can reduce the driving cost of the microelectromechanical device and facilitate the miniaturization of the microelectromechanical device.

Description

Technical Field

[0001] The present invention relates to the technical field of optical communication devices, and in particular to a micro-electromechanical device driven by electrostatic positive and negative pressure differences and a driving method of the device. Background Art

[0002] Electrostatically driven micro-electromechanical systems (MEMS) are widely used in optical devices. MEMS can rotate around its own axis to change the tilt angle of the reflecting plane, thereby changing the emission angle of the reflected light beam and realizing functions such as optical path switching.

[0003] See also Figure 1 An existing electrostatically driven micro-electromechanical device has three opposing plates: a first plate 10, a second plate 15, and a third plate 17. The second plate 15 is typically a fixed plate, meaning it cannot rotate, while the first plate 10 can rotate relative to the second plate 15. The third plate 17 is located within the first plate 10 and can rotate relative to the second plate 15. Two electrodes are provided on the first plate 10, for example, a first working electrode 11 and a second working electrode 12 are provided along a first dimension, while the third plate 17 is also provided with two working electrodes, a third working electrode 13 and a fourth working electrode 14, respectively, along a second dimension. Because the third plate 17 is provided within the first plate 10, when the first plate 10 rotates, it drives the third plate 17 to rotate. It should be noted that another existing electrostatically driven micro-electromechanical device has a comb-tooth structure, which is electrically equivalent to a plate.

[0004] When the first plate 10 needs to be controlled to rotate, a voltage needs to be applied to at least one of the first working electrode 11 and the second working electrode 12 to change the electrostatic field between the first plate 10 and the second plate 15, thereby causing the first plate 10 to deflect relative to the second plate 15. Figure 2 As shown, taking the first dimension as an example, when no voltage is applied to the first working electrode 11 and the second working electrode 12, the first plate 10 and the second plate 15 are in an initial state, and the first plate 10 does not rotate relative to the second plate 15. Typically, the second plate 15 is grounded, so the second plate 15 has a zero potential. When a voltage is applied to the first working electrode 11, due to the unequal voltages between the first working electrode 11 and the second working electrode 12, under the action of electrostatic adsorption, the end of the first plate 10 provided with the first working electrode 11 moves closer to the second plate 15. Correspondingly, the end of the first plate 10 provided with the second working electrode 12 moves away from the second plate 15, thereby achieving rotation of the first plate 10 in the first dimension around the fulcrum 16.

[0005] In the second dimension, the control method for controlling the rotation of the third plate 17 relative to the first plate 10 is similar to the control method for the rotation in the first dimension, and will not be repeated herein.

[0006] Existing electrostatically driven microelectromechanical devices typically employ multiple power supplies, each of which applies a voltage to each electrode, with each electrode receiving a positive DC voltage. Since the rotation angle of the first plate 10 is linearly positively correlated with the voltage applied to each electrode, the greater the voltage applied to each electrode, the greater the rotation angle of the first plate 10. Therefore, to increase the rotation angle of the first plate 10, a higher voltage needs to be supplied to each electrode, which necessitates the use of a power supply with a higher output voltage to supply power to each electrode. Furthermore, since only an attractive force, and no repulsive force, is generated between the first plate 10 and the second plate 15, the rotation angle of the first plate 10 relative to the second plate 15 is only related to the absolute value of the voltage difference between the first working electrode 11 and the second plate 15, and the voltage difference between the second working electrode 12 and the second plate 15, and is unrelated to the positive or negative direction of the voltage difference between the first working electrode 11 and the second plate 15, or the positive or negative direction of the voltage difference between the second working electrode 12 and the second plate 15. For example, if a voltage of +60V is applied to the first working electrode 11 and a voltage of -60V is applied to the second working electrode 12, but the second plate 15 is set to zero voltage, the voltage difference between the first working electrode 11 and the second plate 15 is 60V, and the voltage difference between the second working electrode 12 and the second plate 15 is also 60V. Therefore, the first plate 10 does not rotate. Therefore, conventional electrostatic adsorption MEMS devices do not apply negative voltages to the working electrodes.

[0007] Therefore, when applying existing solutions, on the one hand, using a power supply with a higher output voltage means that the production cost and driving cost of the micro-electromechanical device need to be increased, resulting in a higher production cost of the micro-electromechanical device; on the other hand, a power supply with a higher output voltage often has a larger volume, which is not conducive to the miniaturization of the micro-electromechanical device, and a power supply with a higher output voltage often has poor heat dissipation performance, and the reliability risk of high voltage will also affect the performance of optical devices. Summary of the Invention

[0008] The first object of the present invention is to provide a micro-electromechanical device driven by electrostatic positive and negative pressure differences with reliable performance and low production cost.

[0009] A second object of the present invention is to provide a driving method for a micro-electromechanical system device driven by electrostatic positive and negative pressure differences with low driving cost.

[0010] To achieve the above-mentioned first purpose, the electrostatic positive and negative pressure difference driven micro-electromechanical device provided by the present invention has a first plate and a second plate arranged relatively to each other, the second plate is a fixed plate, and the first plate can rotate relative to the second plate; the first plate is provided with a first working electrode and a second working electrode arranged along a first dimension, and the second plate is provided with at least one reference electrode; the electrostatic positive and negative pressure difference driven micro-electromechanical device obtains a first output power supply and a second output power supply, and the first output power supply and the second output power supply can be selectively output to the first working electrode, the second working electrode or the reference electrode; wherein, one of the first output power supply and the second output power supply is a DC positive voltage, and the other of the first output power supply and the second output power supply is a DC negative voltage; the voltages of the first output power supply and the second output power supply are both fixed values, or the voltages of the first output power supply and the second output power supply are both variable values; or, the voltage of one of the first output power supply and the second output power supply is a fixed value, and the voltage of the other of the first output power supply and the second output power supply is a variable value.

[0011] For example, the micro-electromechanical device is provided with a power conversion circuit, which obtains a first input power from an external power source and converts the first input power into a first output power and a second output power.

[0012] As can be seen from the above scheme, the first output power supply and the second output power supply are respectively a DC positive voltage and a DC negative voltage. Therefore, the first working electrode, the second working electrode, or the reference electrode can be loaded with a positive voltage and a negative voltage, respectively. For example, when the first working electrode is loaded with a positive voltage and the corresponding reference electrode is loaded with a negative voltage, the voltage difference between the first working electrode and the reference electrode increases. Even when the input power of the external power supply is relatively low, a large voltage difference can still be generated. While meeting the requirements for large-angle rotation of the first plate, it can also reduce the input power voltage requirement, lower the production cost of the MEMS device, and facilitate the miniaturization and reliability of electrostatically driven MEMS devices.

[0013] A preferred solution is that the number of reference electrodes is equal to the number of working electrodes provided on the first plate, each reference electrode corresponds to a working electrode, and each reference electrode can be independently loaded with the first output power supply or the second output power supply.

[0014] It can be seen that a corresponding reference electrode is provided for each working electrode, and a different voltage can be applied to each reference electrode, so that the adjustment of the rotation angle of each dimension of the first plate is more flexible.

[0015] Alternatively, the number of the reference electrode is one.

[0016] A further solution is that the micro-electromechanical device also includes a third plate arranged opposite to the first plate, the third plate can rotate relative to the first plate, the third plate is provided with a third working electrode and a fourth working electrode arranged along the second dimension, the micro-electromechanical device obtains a third output power supply and a fourth output power supply, and the third output power supply and the fourth output power supply can be selectively output to the third working electrode, the fourth working electrode or the reference electrode; wherein, one of the third output power supply and the fourth output power supply is a DC positive voltage, and the other of the third output power supply and the fourth output power supply is a DC negative voltage.

[0017] It can be seen that two working electrodes are provided on the first plate and the third plate in two different dimensions respectively, and the working electrodes in the two dimensions can be independently loaded with different voltages, so that the angles of the first plate and the third plate can be independently adjusted in the two dimensions respectively, meeting the adjustment requirements of the micro-electromechanical device at any tilt angle in the two-dimensional direction.

[0018] A further solution is that at least one of the first working electrode, the second working electrode, the third working electrode, the fourth working electrode and the reference electrode can be set to zero voltage.

[0019] It can be seen that each working electrode and reference electrode can be loaded with positive voltage and negative voltage, and can also be set to zero voltage. In this way, appropriate voltage can be flexibly loaded to each electrode according to the actual requirements of the tilt angle of the first plate and the third plate.

[0020] A further solution is that the number of reference electrodes is two, wherein one reference electrode corresponds to the first working electrode and the second working electrode, and the other reference electrode corresponds to the third working electrode and the fourth working electrode.

[0021] To achieve the above-mentioned second purpose, the driving method of the electrostatic positive and negative pressure difference driven micro-electromechanical device provided by the present invention is applied to the electrostatic positive and negative pressure difference driven micro-electromechanical device, the micro-electromechanical device having a first plate and a second plate arranged relatively to each other, the second plate being a fixed plate, and the first plate being rotatable relative to the second plate; the first plate being provided with a first working electrode and a second working electrode arranged along a first dimension, and the second plate being provided with at least one reference electrode; the method comprising: the micro-electromechanical device obtaining a first output power supply and a second output power supply, wherein one of the first output power supply and the second output power supply is a DC positive voltage, and the other of the first output power supply and the second output power supply is a DC negative voltage; the first output power supply is output to one of the first working electrode, the second working electrode and the reference electrode, and the second output power supply is output to the other of the first working electrode, the second working electrode and the reference electrode; the voltages of the first output power supply and the second output power supply are fixed values, or the voltages of the first output power supply and the second output power supply are variable values; or the voltage of one of the first output power supply and the second output power supply is a fixed value, and the voltage of the other of the first output power supply and the second output power supply is a variable value.

[0022] As can be seen from the above scheme, since the first working electrode, the second working electrode, and the reference electrode can be loaded with positive and negative voltages, for example, when the absolute values ​​of the positive and negative voltages loaded on the first and second working electrodes are equal, and the voltage of the reference electrode is equal to the voltage of the first working electrode or the second working electrode, it is equivalent to loading a higher voltage on the first working electrode, while setting the second working electrode to zero voltage. This design can achieve a larger tilt angle of the first plate when the input power voltage is low, reducing the production cost of the micro-electromechanical device and facilitating a reduction in the size of the micro-electromechanical device.

[0023] A preferred solution is that two of the first working electrode, the second working electrode and the reference electrode receive the first output power, and the other of the first working electrode, the second working electrode and the reference electrode receives the second output power; or two of the first working electrode, the second working electrode and the reference electrode receive the second output power, and the other of the first working electrode, the second working electrode and the reference electrode receives the first output power.

[0024] It can be seen that the first output power supply and the second output power supply can be loaded onto two electrodes, and the first output power supply or the second output power supply is loaded onto the reference electrode. In this way, the voltage required to be loaded on each electrode can be flexibly determined according to the requirement of the tilt angle of the first plate.

[0025] An optional solution is that the first working electrode is set to zero voltage, and the second working electrode and the reference electrode receive the first output power supply or the second output power supply.

[0026] A further solution is that the micro-electromechanical device also includes a third plate arranged opposite to the first plate, the third plate can rotate relative to the first plate, and the third plate is also provided with a third working electrode and a fourth working electrode arranged along the second dimension; the micro-electromechanical device also obtains a third output power supply and a fourth output power supply, and the third output power supply and the fourth output power supply can be selectively output to the third working electrode, the fourth working electrode or the reference electrode; wherein, one of the third output power supply and the fourth output power supply is a DC positive voltage, and the other of the third output power supply and the fourth output power supply is a DC negative voltage; the third output power supply is output to one of the third working electrode and the fourth working electrode, and the fourth output power supply is output to the other of the third working electrode and the fourth working electrode.

[0027] It can be seen that the two working electrodes and the reference electrode in the second dimension can also be loaded with a DC positive voltage or a DC negative voltage, thereby increasing the rotation angle of the third plate in the first dimension. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of an existing electrostatically driven micro-electromechanical device.

[0029] Figure 2 This is a schematic diagram of the working principle of an existing electrostatically driven micro-electromechanical device in one dimension.

[0030] Figure 3 1 is a schematic structural diagram of a first embodiment of a micro-electromechanical system device driven by electrostatic positive and negative pressure differences according to the present invention.

[0031] Figure 4 1 is an electrical schematic diagram of a first embodiment of a micro-electromechanical device driven by electrostatic positive and negative pressure differences according to the present invention.

[0032] Figure 5 1 is a schematic structural diagram of a second embodiment of a micro-electromechanical system device driven by electrostatic positive and negative pressure differences according to the present invention.

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0034] The electrostatic positive and negative voltage differential-driven micro-electromechanical device of the present invention is applicable to various optical devices, such as optical path selectors and optical space scanners. The electrostatic positive and negative voltage differential-driven micro-electromechanical device of the present invention receives only the voltage output by an external power supply and converts the input power supply into a DC positive voltage and a DC negative voltage via a power conversion circuit. The DC positive and DC negative voltages are then applied to different electrodes of the micro-electromechanical device, allowing the first plate to be tilted at a larger angle using a relatively low input voltage.

[0035] First embodiment:

[0036] See also Figure 3 The electrostatic positive and negative pressure differential driven micro-electromechanical device of this embodiment comprises a first plate 20, a second plate 25, and a third plate 27. The first plate 20 and the second plate 25 are disposed opposite each other. Preferably, the second plate 25 is a fixed plate and cannot rotate, while the first plate 20 can rotate relative to the second plate 25, thereby enabling adjustment of different tilt angles of the first plate 20. The third plate 27 is disposed within the first plate 20 and is provided with a reflector to reflect a light beam. Thus, when the tilt angle of the first plate 20 or the third plate 27 is adjusted, the reflected light path of the reflected light beam is changed, thereby enabling selection and control of the light path, and realizing functions such as an optical space scanner and an optical switch.

[0037] Two working electrodes are provided on the first plate 20, including a first working electrode 21 and a second working electrode 22 arranged along the first dimension. Two working electrodes are also provided on the third plate 27, namely a third working electrode 23 and a fourth working electrode 24 arranged along the second dimension. A reference electrode 26 is provided on the second plate 25. In this embodiment, Figure 3 The reference electrode 26, shown as a dotted line, is located on the back side of the second plate 25. In this embodiment, providing a single reference electrode 26 means that the reference electrode 26 is electrically integrated. Physically, it can be distributed at multiple locations on the second plate 25, with each reference electrode 26 receiving the same voltage. When no voltage is applied to the four working electrodes and the reference electrode 26, each electrode has zero voltage, and the first plate 20, second plate 25, and third plate 27 are all in their initial state, meaning that the first plate 20 and third plate 27 are not rotating.

[0038] In this embodiment, the power received by the two working electrodes and the reference electrode 26 of the same dimension comes from a single external power source, such as Figure 4As shown, a first external power source 31 provides a first input power source to the microelectromechanical device. The microelectromechanical device includes a power conversion circuit, which includes a first voltage drive circuit 32. The first voltage drive circuit 32 includes a digital-to-analog converter and a voltage amplifier. The digital-to-analog converter is used to convert digital signals into analog DC low-voltage signals. The converted analog DC low-voltage signals are output to two voltage amplifiers. The two voltage amplifiers respectively amplify the input analog DC low-voltage signals into a DC positive voltage or a DC negative voltage with a higher voltage value, thereby forming a first output power source and a second output power source, respectively. Preferably, the absolute values ​​of the voltages of the first output power source and the second output power source are equal, for example, the first output power source is +60V and the second output power source is -60V. The first voltage drive circuit 32 of this embodiment can be implemented using a known power conversion circuit. In addition, if the digital-to-analog converter is used to convert digital signals into analog DC low voltage to meet the voltage requirements, a voltage amplifier is not required.

[0039] Furthermore, the voltages of the first and second output power supplies can be fixed values, or they can vary within a certain voltage range. For example, the first output power supply can vary between 0V and 60V, and the second output power supply can vary between 0V and -60V. Alternatively, the voltage of one of the first and second output power supplies can be fixed, while the voltage of the other can vary. Setting the voltages of the first and second output power supplies to variable values ​​requires setting the voltage output by the voltage conversion circuit to an adjustable value.

[0040] The first output power and the second output power generated by the first voltage driving circuit 32 can be output to one or two of the first working electrode 21, the second working electrode 22, and the reference electrode 26. Specifically, the first voltage driving circuit 32 has two output terminals, which respectively output the first output power and the second output power. Each output terminal is connected to the first working electrode 21, the second working electrode 22, and the reference electrode 26 through a switch that can be controlled to be on or off. By controlling the on and off states of each switch, the requirement of applying different voltages to the first working electrode 21, the second working electrode 22, and the reference electrode 26 can be achieved. In addition, the first working electrode 21, the second working electrode 22, and the reference electrode 26 can also be set to zero voltage. In this case, it is only necessary to connect the electrode set to zero voltage to the ground (zero voltage) of the first voltage driving circuit 32.

[0041] Figure 4The relationship between the two output ends of the first voltage driving circuit 32 and the first working electrode 21, the second working electrode 22, and the reference electrode 26 is schematically represented by the first switch 34 and the second switch 35. In fact, there are a large number of switches between the two output ends of the first voltage driving circuit 32 and the first working electrode 21, the second working electrode 22, and the reference electrode 26, which are not shown one by one in the figure. Figure 4 , X+ represents the first working electrode 21 , X− represents the second working electrode 22 , and COM represents the reference electrode 26 .

[0042] In addition, a second external power supply 36 provides a second input power source to the microelectromechanical device. The power conversion circuit also includes a second voltage drive circuit 37, which also includes a digital-to-analog converter and a voltage amplifier. The digital-to-analog converter is used to convert digital signals into analog DC low-voltage signals. The converted analog DC low-voltage signals are output to two voltage amplifiers. The two voltage amplifiers amplify the input analog signals into a higher voltage DC positive voltage or DC negative voltage, thereby forming a third output power source and a fourth output power source, respectively. In one embodiment, the absolute values ​​of the voltages of the third and fourth output power sources are equal, for example, the third output power source is +60V and the fourth output power source is -60V.

[0043] Furthermore, the voltages of the third and fourth output power supplies may be fixed values, or they may vary within a certain voltage range. Alternatively, the voltage of one of the third and fourth output power supplies may be fixed, while the voltage of the other may vary.

[0044] The second voltage driving circuit 37 outputs the third working power supply or the fourth working power supply to the third working electrode 23, the fourth working electrode 24 or the reference electrode 26 through the third switch 38 and the fourth switch 39. Figure 4 Here, Y+ represents the third working electrode 23 , and Y− represents the fourth working electrode 24 .

[0045] It should be noted that the adjustment of the tilt angle of the microelectromechanical device in two dimensions is performed independently, that is, a voltage can be applied to the electrodes in any dimension independently without considering the voltage applied to the electrodes in the other dimension. For example, when it is necessary to control the first plate 20 to rotate counterclockwise along the first dimension (e.g., the X-axis direction), a first output voltage can be output to the first working electrode 21, and a second output voltage can be applied to the second working electrode 22 and the reference electrode 26. That is, a positive DC voltage is applied to the first working electrode 21, and a negative DC voltage is applied to the second working electrode 22 and the reference electrode 26. Since the voltage difference between the second working electrode 22 and the reference electrode 26 is zero, while the voltage difference between the first working electrode 21 and the reference electrode 26 is large, the first plate 20 can rotate a larger angle. For example, if the voltage output by the first external power supply 31 is 60V, and after conversion by the first voltage driving circuit 32, the first output power is +60V and the second output power is -60V, then the voltage applied to the first working electrode 21 is +60V, while the voltage applied to the second working electrode 22 and the reference electrode 26 is -60V. The voltage difference between the first working electrode 21 and the reference electrode 26 is 120V. Compared to conventional micro-electromechanical devices, where the maximum voltage difference between the first working electrode and the reference electrode is only 60V, this embodiment can significantly increase the voltage difference between the first working electrode 21 and the reference electrode 26, allowing the first plate 20 to rotate through a larger angle.

[0046] Since the third plate 27 does not need to rotate in the second dimension, the same voltage as the reference electrode 26 needs to be applied to the third working electrode 23 and the fourth working electrode 24, that is, the third working electrode 23 and the fourth working electrode 24 are also applied with a voltage of -60V. Therefore, the second voltage driving circuit 37 needs to apply a voltage of -60V to the third working electrode 23 and the fourth working electrode 24.

[0047] Of course, if a voltage of +60V is applied to the first working electrode 21 and a voltage of -60V is applied to the second working electrode 22, but if the reference electrode 26 is set to zero voltage, then since the voltage difference between the first working electrode 21 and the reference electrode 26 is 60V, the voltage difference between the second working electrode 22 and the reference electrode 26 is also 60V, then the first plate 20 will not rotate at this time.

[0048] It can be seen that compared with traditional micro-electromechanical devices, the absolute value of the voltage loaded to the first working electrode 21 and the second working electrode 22 is lower, so the micro-electromechanical device has lower requirements for the first input power supply and the second input power supply provided by the first external power supply 31 and the second external power supply 36, thereby reducing the production cost and driving cost of the micro-electromechanical device.

[0049] Moreover, in this embodiment, the micro-electromechanical device is only connected to two external power supplies, that is, only two external power supplies are used to power the micro-electromechanical device. The number of external power supplies used is relatively small, which is also convenient for integrating the internal power conversion circuit when used on a large scale, and can further reduce the driving cost of the micro-electromechanical device.

[0050] Furthermore, since the first external power supply 31 and the second external power supply 36 with lower input voltage usually have the advantages of small size and low heat generation, they are also conducive to the miniaturization of micro-electromechanical devices. The less heat generated can also avoid the performance of optical devices being affected by overheating of optical devices.

[0051] Similarly, when it is necessary to control the first plate 20 to rotate clockwise along the first dimension, the first output voltage can be output to the second working electrode 22, and the second output voltage can be applied to the first working electrode 21 and the reference electrode 26, that is, a DC positive voltage is applied to the second working electrode 22, and a DC negative voltage is applied to the first working electrode 21 and the reference electrode 26, and the same voltage as the first working electrode is applied to the third working electrode 23 and the fourth working electrode 24.

[0052] When it is necessary to control the third plate 27 to rotate counterclockwise along the second dimension (e.g., the Y-axis direction), the third output voltage can be output to the third working electrode 23, and the fourth output voltage can be applied to the fourth working electrode 24 and the reference electrode 26, and the same voltage as the reference electrode 26 can be applied to the first working electrode 21 and the second working electrode 22. When it is necessary to control the third plate 27 to rotate clockwise along the second dimension, the third output voltage can be output to the fourth working electrode 24, and the fourth output voltage can be applied to the third working electrode 23 and the reference electrode 26, and the same voltage as the reference electrode 26 can be applied to the first working electrode 21 and the second working electrode 22.

[0053] Optionally, the output power of the external power supply is a +60V DC positive voltage. In this case, the power conversion circuit does not need to convert the output power and can directly output a DC positive voltage, but needs to convert the DC positive voltage into a DC negative voltage. This type of power conversion circuit will be simpler.

[0054] If the MEMS device needs to be tilted in two dimensions, corresponding voltages need to be applied to the working electrodes in the two dimensions. For example, voltages are first applied to the first working electrode 21 and the second working electrode 22 in the first dimension. While maintaining the voltages applied to the first working electrode 21 and the second working electrode 22, voltages are then applied to the third working electrode 23 and the fourth working electrode 24 in the second dimension. In this way, the third plate 27 can be tilted at any angle in the two-dimensional directions.

[0055] For example, when a +60V voltage is applied to the first working electrode 21 and a -60V voltage is applied to the second working electrode 22, if a -60V voltage is applied to the reference electrode 26, the voltage difference between the first working electrode 21 and the reference electrode 26 is 120V, and the voltage difference between the second working electrode 22 and the reference electrode 26 is 0, resulting in a large rotation angle of the first plate 20. However, if a +60V voltage is applied to the first working electrode 21 and a -60V voltage is applied to the second working electrode, while the reference electrode 26 is set to zero voltage, the voltage difference between the first working electrode 21 and the reference electrode 26 is 60V, and the voltage difference between the second working electrode 22 and the reference electrode 26 is also 60V, and the first plate 20 does not rotate relative to the second plate 25. Thus, the rotation angle of the first plate 20 can be changed by switching the voltage of the reference electrode 26.

[0056] Based on the above, if a digital-to-analog converter is used to convert digital signals into analog signals and output a continuous voltage signal to each electrode, this embodiment can also improve the resolution of the digital-to-analog converter. For example, the negative voltage applied to the electrode has a range of -(3 / 2)V0, -V0, and -(1 / 2)V0, while the positive voltage applied to the electrode is variable. For example, when the positive voltage ranges from 0V to +(1 / 2)V0, this embodiment can achieve an electrostatic adsorption force corresponding to 0V to 2V0, equivalent to improving the resolution and accuracy of the digital-to-analog converter by two digits. Therefore, this embodiment can achieve higher-precision drive control within a smaller voltage range, eliminating the need for higher drive voltages to achieve high-precision control, thereby reducing the driving cost of the microelectromechanical device.

[0057] Second embodiment:

[0058] See also Figure 5 The electrostatic positive and negative pressure differential driven micro-electromechanical device of this embodiment comprises a first plate 40, a second plate 50, and a third plate 60. The first plate 40 and the second plate 50 are disposed opposite each other. Preferably, the second plate 50 is a fixed plate and cannot rotate, while the first plate 40 can rotate relative to the second plate 50, thereby adjusting the first plate 40 to different tilt angles. The third plate 60 is disposed within the first plate 40 and can rotate relative to the first plate 40. A reflector can be provided on the third plate 60 to reflect the light beam.

[0059] Two working electrodes are provided on the first plate 40, including a first working electrode 41 and a second working electrode 42 arranged along the first dimension. The third plate 60 is also provided with two working electrodes, namely a third working electrode 43 and a fourth working electrode 44 arranged along the second dimension. Four reference electrodes are provided on the second plate 50, namely a first reference electrode 51 and a second reference electrode 52 arranged along the first dimension, and a third reference electrode 53 and a fourth reference electrode 54 arranged along the second dimension. Each reference electrode corresponds to a working electrode, for example, the first reference electrode 51 corresponds to the first working electrode 41, the second reference electrode 52 corresponds to the second working electrode 42, and so on.

[0060] The power received by the multiple working electrodes and the multiple reference electrodes comes from two or more external power sources, or a single external power source. Furthermore, the microelectromechanical device has a power conversion circuit, which has two voltage drive circuits, each of which has a digital-to-analog converter and two voltage amplifiers. The digital-to-analog converter is used to convert digital signals into analog DC low-voltage signals, and output the converted analog signals to the two voltage amplifiers. The two voltage amplifiers amplify the input analog DC low-voltage signals into DC positive voltage and DC negative voltage with higher voltage values, thereby forming the first output power supply, the second output power supply, the third output power supply, and the fourth output power supply, respectively. Furthermore, if the digital-to-analog converter is used to convert digital signals into analog DC low voltage, the voltage requirement can be met without a voltage amplifier. The first output power supply and the second output power supply can be output to the first working electrode 41, the second working electrode 42, and the first reference electrode 51, the second reference electrode 52, and the third output power supply and the fourth output power supply can be output to the third working electrode 43, the fourth working electrode 44, and the third reference electrode 53, the fourth reference electrode 54. The voltage applied to each working electrode and each reference electrode is determined according to the required tilt angles of the first plate 40 and the third plate 60 .

[0061] For example, when it is necessary to control the first plate 40 to rotate counterclockwise along the first dimension (for example, the X-axis direction), the first output voltage can be output to the first working electrode 41, and the second output voltage can be applied to the first reference electrode 51, and the other working electrodes and the reference electrode are grounded, that is, a DC positive voltage is applied to the first working electrode 41, and a DC negative voltage is applied to the first reference electrode 51, and the other working electrodes and the reference electrode are set to zero voltage. Similarly, when it is necessary to control the first plate 40 to rotate clockwise along the first dimension, the first output voltage can be output to the second working electrode 42, and the second output voltage can be applied to the second reference electrode 52, and the other working electrodes and the reference electrode are grounded, that is, a DC positive voltage is applied to the second working electrode 42, and a DC negative voltage is applied to the second reference electrode 52, and the other working electrodes and the reference electrode are set to zero voltage. The rotation control in the second dimension is similar to the rotation control in the first dimension and will not be repeated.

[0062] Since a voltage is applied to each reference electrode independently, compared with the first embodiment, this embodiment can flexibly apply different voltages to each reference electrode to flexibly adjust the rotation angle of the micro-electromechanical device in the first dimension and the second dimension.

[0063] Third embodiment:

[0064] The electrostatic positive and negative pressure difference driven micro-electromechanical device of this embodiment comprises a first plate, a second plate, and a third plate. The first plate and the second plate are arranged opposite to each other. The second plate is a fixed plate and cannot rotate, while the first plate can rotate relative to the second plate. The third plate is arranged inside the first plate and can rotate relative to the first plate. A reflector can be provided on the third plate to reflect the light beam through the reflector.

[0065] Two working electrodes are provided on the first plate, including a first working electrode and a second working electrode arranged along the first dimension. The third plate is also provided with two working electrodes, namely a third working electrode and a fourth working electrode arranged along the second dimension. Unlike the second embodiment, this embodiment provides two reference electrodes on the second plate, one of which corresponds to the first and second working electrodes, and the other corresponds to the third and fourth working electrodes. Each reference electrode can be independently applied with a voltage. The other structures of this embodiment are the same as those of the second embodiment and are not further described.

[0066] From the above embodiments, it can be seen that the reference electrodes corresponding to the working electrodes can be electrically arranged separately or combined, that is, voltages can be applied to them uniformly or separately, and neither method affects the implementation of the present invention.

[0067] In the case where the reference electrode is provided separately, as in the second and third embodiments, control flexibility is increased, and the working and reference electrodes in two different dimensions can be controlled independently. If two working electrodes in the same dimension do not need to have different voltages applied simultaneously, combining the reference electrodes, as in the first embodiment, can save costs.

[0068] As can be seen, the MEMS device of the present invention only requires a small amount of external power. The power conversion circuit converts the input power into a positive DC voltage and a negative DC voltage, and outputs the positive DC voltage or negative DC voltage to different working electrodes and reference electrodes to adjust the tilt angle of the first and third plates. When the input power voltage is low, the first and third plates can have a larger tilt angle. This embodiment can reduce the production and driving costs of the MEMS device and is also conducive to the miniaturization of the MEMS device.

[0069] In addition, under the conditions of the same driving voltage difference and the same driving voltage accuracy, the present invention introduces a negative voltage that is the same as the positive voltage, thereby reducing the voltage required to be provided by the external power supply while also improving the accuracy of the driving voltage by one bit, making the tilt angle adjustment of the micro-electromechanical device more precise.

[0070] Finally, it should be emphasized that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A micro-electromechanical device driven by electrostatic positive and negative pressure differences, comprising a first plate and a second plate disposed opposite each other, wherein the second plate is a fixed plate and the first plate is capable of rotating relative to the second plate; The first plate is provided with a first working electrode and a second working electrode arranged along a first dimension, and the second plate is provided with at least one reference electrode; Its characteristics are: The electrostatic positive and negative pressure difference driven micro-electromechanical device obtains a first output power and a second output power, and the first output power and the second output power can be selectively output to the first working electrode, the second working electrode or the reference electrode; Wherein, one of the first output power supply and the second output power supply is a DC positive voltage, and the other of the first output power supply and the second output power supply is a DC negative voltage; The voltages of the first output power supply and the second output power supply are both fixed values, or the voltages of the first output power supply and the second output power supply are both variable values; or the voltage of one of the first output power supply and the second output power supply is a fixed value, and the voltage of the other of the first output power supply and the second output power supply is a variable value; The first output power supply can be output to the first working electrode, and the second output power supply can be output to the second working electrode and the reference electrode to increase the voltage difference between the first working electrode and the reference electrode, which corresponds to the first working electrode and the second working electrode.

2. The electrostatic positive and negative pressure differential driven micro-electromechanical device according to claim 1, characterized in that: The number of the reference electrodes is equal to the number of the working electrodes provided on the first flat plate, and each of the reference electrodes corresponds to one of the working electrodes.

3. The electrostatic positive and negative pressure differential driven micro-electromechanical system device according to claim 1, characterized in that: The micro-electromechanical device further includes a third plate disposed opposite to the first plate, the third plate being rotatable relative to the first plate, and the third plate further being provided with a third working electrode and a fourth working electrode arranged along a second dimension; The second plate is provided with at least one other reference electrode corresponding to the third working electrode and the fourth working electrode; The micro-electromechanical device further obtains a third output power supply and a fourth output power supply, wherein the third output power supply and the fourth output power supply can be selectively output to the third working electrode, the fourth working electrode or the other reference electrode; Wherein, one of the third output power supply and the fourth output power supply is a DC positive voltage, and the other of the third output power supply and the fourth output power supply is a DC negative voltage.

4. The electrostatic positive and negative pressure differential driven micro-electromechanical system device according to claim 3, characterized in that: At least one of the first working electrode, the second working electrode, the third working electrode, the fourth working electrode, and the reference electrode can be set to zero voltage.

5. The electrostatic positive and negative pressure differential driven micro-electromechanical device according to claim 3 or 4, characterized in that: The number of the reference electrodes is four, two of which correspond to the first working electrode and the second working electrode respectively, and the other two correspond to the third working electrode and the fourth working electrode respectively.

6. A method for driving a micro-electromechanical system (MEMS) device driven by electrostatic positive and negative pressure differentials, applied to a MEMS device driven by electrostatic positive and negative pressure differentials, wherein the MEMS device comprises a first plate and a second plate disposed opposite each other, the second plate being a fixed plate and the first plate being rotatable relative to the second plate; The first plate is provided with a first working electrode and a second working electrode arranged along a first dimension, and the second plate is provided with at least one reference electrode; It is characterized in that The method includes: The micro-electromechanical device obtains a first output power supply and a second output power supply, wherein one of the first output power supply and the second output power supply is a DC positive voltage and the other of the first output power supply and the second output power supply is a DC negative voltage; The voltages of the first output power supply and the second output power supply are fixed values, or the voltages of the first output power supply and the second output power supply are variable values; or the voltage of one of the first output power supply and the second output power supply is fixed value, and the voltage of the other of the first output power supply and the second output power supply is variable value; The first output power supply can be output to the first working electrode, and the second output power supply can be output to the second working electrode and the reference electrode to increase the voltage difference between the first working electrode and the reference electrode, which corresponds to the first working electrode and the second working electrode.

7. The driving method of a micro-electromechanical system device driven by electrostatic positive and negative pressure differences according to claim 6, characterized in that: The micro-electromechanical device further includes a third plate disposed opposite to the first plate, the third plate being rotatable relative to the first plate, the third plate further being provided with a third working electrode and a fourth working electrode arranged along a second dimension, and the second plate further being provided with at least one other reference electrode corresponding to the third working electrode and the fourth working electrode; The micro-electromechanical device further obtains a third output power supply and a fourth output power supply, wherein the third output power supply and the fourth output power supply can be selectively output to the third working electrode, the fourth working electrode or the other reference electrode; Wherein, one of the third output power supply and the fourth output power supply is a DC positive voltage, and the other of the third output power supply and the fourth output power supply is a DC negative voltage; The third output power is output to one of the third working electrode and the fourth working electrode, and the fourth output power is output to the other of the third working electrode and the fourth working electrode.

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