MEMS device with meandering electrodes

Abstract

Microelectromechanical device comprising a mobile rotor (21) and a stationary stator (22) lying in a device plane defined by a lateral axis and a transverse axis, wherein the transverse axis is orthogonal to the lateral axis and the device has at least one measuring region, wherein an edge (219) of the rotor (21) and an edge (229) of the stator (22) are separated from each other by a rotor-stator space, and a rotor electrode (211) extends in the rotor-stator space from the edge (219) of the rotor (21) to the stator, and a first stator electrode extends in the rotor-stator space from the edge (229) of the stator (22) to the rotor (21), and the rotor electrode and the first stator electrode are adjacent and substantially parallel to each other in the rotor-stator space. wherein the rotor electrode (211) is a meandering electrode having two or more first lateral sections (2111a, 2111b) lying on a first lateral baseline (291), and each first lateral section is separated from the adjacent first lateral section on the first lateral baseline (291) by a first lateral space (281), wherein the rotor electrode is a folded beam having a serpentine shape, and the first stator electrode (221) is a meandering electrode having two or more second lateral sections (2211a, 2211b) lying on a second lateral baseline (292) and each second lateral section being separated from the adjacent second lateral section on the second lateral baseline (292) by a second lateral space (282), wherein the stator electrode is a folded beam having a serpentine shape, wherein at least a first lateral space (281) is adjacent to at least a second lateral space (282) and is at least partially aligned in the transverse direction with the at least one second lateral space (282), characterized in that the at least one first lateral space (281) is partially and not completely aligned in the transverse direction with the at least one second lateral space (282) when the rotor (21) is in its initial position.

Description

[0001] The disclosure relates to microelectromechanical devices, and in particular to devices comprising a mobile mass element that can move relative to a surrounding stationary structure. The present disclosure further relates to electrodes that can be provided on the mobile mass element and on the stationary structure to measure this movement.

[0002] Microelectromechanical systems (MEMS) often feature a mobile mass element, which can be referred to as a rotor. The rotor is typically suspended from a stationary structure by flexible suspension devices that allow the rotor to move relative to the stationary structure. The stationary structure can be called the stator. The rotor's movement can be measured using a capacitive transducer, which has a set of elongated electrode structures on the rotor that interlock with a corresponding set of elongated electrode structures on the stator.

[0003] Fig. 1a and Fig. Figure 1b presents two possible implementations of a capacitive transducer with elongated electrodes. The figures depict a rotor 11 with a set of rotor electrodes 111-113 and a stator 12 with a set of stator electrodes 121-123. The arrow next to the rotor 111 represents its direction of movement (the x-direction). Fig. 1a The rotor and stator electrodes extend in a direction (the y-direction) that is perpendicular to the direction in which the rotor 11 moves. The distance between each rotor / stator electrode increases or decreases in the x-direction as the rotor moves. In this measurement, the capacitive response is sensitive to, or responds to, the displacement of the rotor, but the relationship between the response and the displacement is not linear.

[0004] In Fig. 1b the rotor and stator electrodes extend in the direction (the x-direction) in which the rotor 11 moves. Fig. Figure 1c shows the positions of a first rotor electrode 111 and a first stator electrode 121 when the rotor is in its rest position. Fig. Figure 1d represents the positions of the same electrodes when the rotor has moved a distance Δx to the left from its rest position. The capacitance between the two electrodes increases as their overlap in the x-direction increases. In this measurement, the relationship between the capacitive response and the displacement is linear, but the capacitance increase that occurs in Fig. The value obtained in 1d is often quite small compared to the capacitance measured in the resting position. Therefore, the measurement signal is not particularly sensitive.

[0005] KR 10 2009 063 079 A discloses a parameter amplification of a MEMS gyroscope by capacitance modulation. DE 11 2013 002 941 T5 discloses a sensor for a physical quantity of the capacitive type. DE 103 53 693 A1 discloses a capacitive accelerometer.

[0006] The object of the present invention is to create a microelectromechanical device with improved characteristics.

[0007] This problem is solved by a device according to claim 1.

[0008] The revelation is based on the concept of using rotor and stator electrodes with a meandering shape. With a suitable arrangement, such electrodes can be used to measure a capacitive response that is highly sensitive to rotor displacement and also exhibits a linear dependence on this displacement.

[0009] Preferred embodiments of the present invention are explained in more detail below with reference to the accompanying drawings. These show: Fig. 1a-1b capacitive transducers implemented with elongated electrodes; Fig. 1c-1d how the capacitance changes when the rotor moves; Fig. 2a-2c Rotor and stator electrodes; Fig. 3a-3b the change in main capacitance during a measurement where the meander structures of the rotor and stator electrodes are partially aligned in the initial position; Fig. 3c-3d the change in main capacitance during a measurement where the meander structures of the rotor and stator electrodes are fully aligned in the initial position; Fig. 3e stray capacitance components; Fig. 4a-4c Design options for a meandering electrode; and Fig. 5a-5b a device in which a meandering rotor electrode is flanked on both sides by meandering stator electrodes.

[0010] This disclosure describes a microelectromechanical device comprising a mobile rotor and a stationary stator lying in a device plane defined by a lateral axis and a transverse axis. The transverse axis is orthogonal to the lateral axis, and the device has at least one measuring region where an edge of the rotor and an edge of the stator are separated by a rotor-stator gap. A rotor electrode extends in the rotor-stator gap from the edge of the rotor to the stator. A first stator electrode extends in the rotor-stator gap from the edge of the stator to the rotor. The rotor electrode and the first stator electrode are adjacent and substantially parallel to each other in the rotor-stator gap.

[0011] The rotor electrode is a meandering electrode having two or more first lateral sections lying on a first lateral baseline, and each first lateral section is separated from the adjacent first lateral section on the first lateral baseline by a first lateral space.

[0012] The first stator electrode is a meandering electrode having two or more second lateral sections lying on a second lateral baseline, with each second lateral section separated from the adjacent second lateral section on the second lateral baseline by a second lateral space. At least one first lateral space is adjacent to at least one second lateral space and is at least partially aligned with the at least one second lateral space in the transverse direction.

[0013] The rotor and stator electrodes are folded beams with a serpentine shape. In other words, each of these meandering electrodes is a beam with a set of successive turns. The folds in the beam can, for example, have multiple perpendicular sections—lateral sections connected by transverse sections. Lateral sections lying on a first lateral baseline are, in this case, connected by transverse sections to lateral sections lying on a different lateral baseline. The connecting structure linking two lateral sections on the first baseline therefore contains two transverse sections with an additional lateral section between them. The perpendicular sections of the folded beam thus form a narrow, meandering electrode with a rectangular structure.

[0014] However, the folds in the beam and the resulting turns of the meandering electrode need not necessarily be perpendicular. Instead of being connected by a square or rectangular fold, the lateral sections lying on the same axis can alternatively be connected by a linking structure with a different geometry, as described and illustrated in more detail below.

[0015] Although general measurement and design principles are discussed below with reference to the figures, which depict only one or two elongated electrodes in each set of rotor and stator electrodes, the sets could be extended to include any number of electrodes. Any principle that applies to one depicted rotor-stator electrode pair also applies to additional rotor-stator electrode pairs arranged adjacent to each other with the same geometry.

[0016] Fig. Figure 2a represents a rotor 21 and a stator 22. A rotor electrode 211 extends from the edge 219 of the rotor 21 to the stator 22, and a first stator electrode 221 extends from the edge 229 of the stator 22 to the rotor 21. The rotor and stator electrodes have a meandering shape. The lateral direction is the x-direction, and the transverse direction is the y-direction. The edge 219 of the rotor is separated from the edge 229 of the stator by a rotor-stator gap 25.

[0017] The rotor electrode 211 has first lateral sections 2111a and 2111b lying on a first lateral baseline 291. Two first lateral sections are shown, but many more could be used. Each pair of first lateral sections (2111a + 2111b) is separated from each other on the first lateral baseline 291 by a first lateral gap 281. Each first lateral section 2111a is connected to the following first lateral section 2111b by a first connecting structure 213, which extends away from the first lateral baseline 291 and leaves the first lateral gap 281 between the first lateral sections 2111a and 2111b. These first connecting structures 213 can have any shape and size suitable for separating the first lateral sections from each other by the desired first lateral gaps 281.

[0018] The first stator electrode 221 has second lateral sections 2211a and 2211b, which lie on a second lateral baseline 292. Each pair of second lateral sections (2211a + 2211b) is separated from each other on the second lateral baseline 292 by a second lateral space 282. Each second lateral section 2211a is connected to the following second lateral section 2211b by a second connecting structure 223, which extends away from the second lateral baseline 292. The shapes of these second connecting structures 223 can also be freely chosen, as long as they separate the second lateral sections from each other by the desired second lateral spaces 282.

[0019] Fig. Figure 2a represents a situation where the rotor 211 is in an initial position. In one embodiment of this disclosure, the initial position can, for example, be a rest position assumed by the rotor in an accelerometer when the accelerometer experiences no acceleration in the x-axis direction. Alternatively, if the rotor and stator are used in a gyroscope, the rotor can, for example, be driven in linear primary oscillation in the y-axis direction. It can oscillate in the x-axis direction when the gyroscope undergoes rotation about a z-axis perpendicular to the xy-plane. In this case, the initial position can be defined by the x-coordinate of the rotor when the gyroscope experiences no rotation about the z-axis. In either case, a capacitive measurement can be performed between the rotor and stator electrodes.The measured capacitance indicates the displacement of the rotor away from its initial position in the x-axis direction, i.e., the lateral direction. In this explanation, the words "left" and "right" refer to two opposite lateral directions, corresponding to the left and right sides of the figures.

[0020] Fig. Figure 2a represents an arrangement where the at least one first lateral gap 281 is partially aligned in the transverse direction with the at least one second lateral gap 282 when the rotor 21 is in its initial position. This means that there is a lateral offset between at least one side of the gaps (left or right side or both sides). Fig. Figure 2a shows an arrangement where the widths of the spaces 281 and 282 are equal and each side of the second lateral space 282 is offset from the corresponding side of the first lateral space 281 by the same lateral offset distance O.

[0021] In each embodiment of this disclosure, where lateral gaps are partially aligned, each pair of partially aligned lateral gaps can be arranged such that the lateral distance from the left side of the first lateral gap 281 to the left side of the second lateral gap 282 (a distance corresponding to the offset distance O in Fig. 2a corresponds) is less than the lateral distance from the left side of the first lateral gap 281 to the right side of the second lateral gap 282 (a distance which in Fig. 2a is displayed as D). Alternatively or additionally, the lateral distance (in Fig. 2a not shown) from the right side of the second lateral gap 282 to the right side of the first lateral gap 281 be less than the lateral distance from the right side of the second lateral gap 282 to the left side of the first lateral gap 281 (in Fig. 2a shown as D). However, the relationship between these distances could alternatively be the opposite (D could be smaller than O in Fig. 2a).

[0022] The first and second lateral spaces 281 and 282 do not necessarily have to be the same width if the spaces are partially aligned. Fig. Figure 2b represents an alternative arrangement where the widths differ and where only the right side of the second lateral space 282 is laterally offset from the right side of the first lateral space 281. The left sides of the two spaces are aligned with each other.

[0023] The at least one first lateral gap 281 can alternatively be fully aligned in the transverse direction with the at least one second lateral gap 282 when the rotor 21 is in its initial position. This option is in Fig. Figure 2c illustrates this. In this case, the first and second lateral gaps have the same lateral width, and there is no lateral offset between the two gaps. Both the left and right sides of the gaps are aligned with each other.

[0024] The principles of capacitive measurement are explained with reference to Fig. 3a-3c describes where reference numerals 31, 32, 311 and 321 correspond to reference numerals 21, 22, 211 and 221 respectively in the Fig. 2a-2c correspond.

[0025] Fig. Figure 3a shows the rotor and stator electrodes 311 and 321 when the rotor is in its initial position. The meander structures in the rotor electrode are offset from the corresponding meander structures in the stator electrode by a lateral offset distance O. The main components of the capacitance between the rotor and stator electrodes in Fig. 3a. Capacitive components arise from the areas that are closest to each other. These components are represented by arrows, and their sum is called the main capacitance. Additional, but smaller, capacitive components arise in the areas that are not directly adjacent to each other. The sum of these components can be called the stray capacitance.

[0026] Fig. Figure 3b represents a situation where the rotor 31 has been displaced to the left from its initial position by a distance Δx. Due to the fact that the meandering structures of the rotor electrode 311 and those of the stator electrode 312 in the Fig. Since the initial positions shown in 3a were offset from each other by an offset distance O, the main capacity is in Fig. 3b larger than in Fig. 3a. The movement of rotor 31 in the x-direction has almost aligned the meandering structures with each other in the y-axis direction. The overlap between the lateral sections that are closest to each other has therefore increased.

[0027] It is essential that each lateral section in the meandering structure contributes to an additional increase in the main capacity. This can be schematically compared to the movement that occurs in Fig. Figure 1d shows where the capacity increase is compared to Fig. 1c was represented with only two additional arrows. In contrast, in Fig. 3b each lateral section in the meandering electrode contributes to the increase in the main capacitance, with two additional arrows compared to Fig. 3a. The original 12 arrows of the starting position in Fig. 3a therefore 20 arrows will be placed in Fig. 3b. Electrodes with a meandering shape can therefore generate a capacitive response that is both linear and highly sensitive, since the capacitive area changes at each turn in the meandering structure. Fig. 3b increased, not only at the tip of the electrode as in Fig. 1d.

[0028] Sensitivity can be increased by increasing the number of lateral sections of each electrode—that is, by increasing the number of turns in the meandering structure. However, some practical limitations must be considered. In the Fig. In the arrangement shown in 3a - 3b, the meander shapes and their offset were designed so that the expected maximum displacement Δx max (which is assumed here to be approximately equal to Δx, represented in Fig. 3b) is not greater than the offset distance O in Fig. 3a. If this were not the case, and if the rotor 31 were to move to the left by a distance exceeding the offset distance, then the overlap between the adjacent meander turns (and thus the main capacitance) would gradually decrease as a function of the displacement as the rotor electrode 311 moves further along the stator electrode 321 than is specified in Fig. Figure 3b is shown. The measured capacity values ​​would then not show a linear dependence on the displacement, and some capacity values ​​would correspond to multiple displacement values. The offset should therefore be the expected maximum displacement in the Fig. 2a and Fig. 2b and in the following Fig. 5a and Fig. exceed the exemplary embodiments shown in 5b.

[0029] Fig. 3c - 3d represent the measurement that can be performed when the first and second lateral gaps are fully aligned in the initial position, as shown in Fig. 2c. Fig. Figure 3c represents the initial position where the meandering curves of the rotor and stator electrodes are fully aligned in the transverse direction (the y-direction). The main capacitance is at its maximum in the illustrated initial position (represented by 20 arrows). Fig. Figure 3d represents a situation where the rotor has moved to the right from its initial position. The main capacitance has decreased, so that only 12 arrows remain. A corresponding decrease in capacitance would be obtained if the rotor moved to the left. In this embodiment, the movement of rotor 31 can be limited to either a movement to the right from the initial position or a movement to the left, since these two movements cannot be distinguished from each other in the capacitive measurement.

[0030] In Fig. 3D should show the expected maximum displacement Δx max be smaller than the widths of the first and second lateral sections and the widths of the first and second lateral gaps. If this were not the case, the overlap between the adjacent meander structures (and thus the main capacity) would not decrease as a linear function of the displacement.

[0031] Fig. 3e places the rotor in the same initial position as in Fig. 3a. Reference numerals 313 and 3233 correspond to reference numerals 213 and 223 respectively in Fig. 2a. Reference numeral 3111 corresponds to reference numerals 2111a and 2111b and reference numeral 2111 corresponds to 2111a and 2111b in Fig. 2a - 2c. The arrows between the rotor electrode and the first stator electrode represent the components that contribute to stray capacitance. These can include the capacitance between each first or second lateral section 3111 / 3211 and the opposite connecting section 313 / 323, the capacitance between first and second lateral sections that are not adjacent to each other, and the capacitance between opposite connecting sections 313 / 323. The magnitude of the stray capacitance depends on the distance between the rotor and stator electrodes and on their geometry and dimensions.

[0032] The measured capacitance is always the sum of the main capacitance and the stray capacitance, and the stray capacitance will generally not show a completely linear dependence on the displacement. However, the main capacitance can be much larger than the stray capacitance because the regions where the electrodes are closest to each other contribute most to the capacitance between them. The influence of the stray capacitance on the measured capacitance can also be minimized with a suitable electrode design.

[0033] Fig. 4a–4c represent some options for an electrode design. Reference numerals 41, 42, 411, 419, 421, 413, 423, 429, 481, 482, 491, and 492 correspond to reference numerals 21, 22, 211, 219, 221, 213, 223, 229, 281, 282, 291, and 292, respectively, in [reference number missing]. Fig. 2a - 2c. Reference numeral 4111 corresponds to reference numerals 2111a and 2111b and reference numeral 4211 corresponds to 2211a and 2211b in Fig. 2a - 2c.

[0034] Fig. Figure 4a represents a rotor electrode with four first lateral sections 4111, four second lateral sections 4211, three first lateral spaces 481, and three second lateral spaces 482. The figure depicts the rotor in its initial position. Each first lateral space 481 in Fig. 4a is laterally offset from the adjacent second lateral gap 482 by the same lateral offset distance. However, the lateral offset distance need not necessarily be the same for each pair of first and second lateral gaps, as long as the expected maximum displacement of the rotor is less than the smallest lateral offset in the direction of motion.

[0035] Each first lateral gap and each second lateral gap can have the same lateral width, as it Fig. 4a. Alternatively, the widths of some first or second lateral spaces may differ, as shown. Fig. 4b represents. Each first lateral section and each second lateral section can have the same lateral width, as shown. Fig. 4b. Alternatively, some first lateral sections may have widths that differ both from the widths of other first lateral sections and from the widths of some second lateral sections, as shown. Fig. 4a represents.

[0036] The rotor electrode may have a separate base section attached to the edge 419 of the rotor, and the first lateral sections 4111 and the first connecting structures 413 may be connected to this base section in alternating sequence. The first stator electrode could have a corresponding base section to which the second lateral sections 2411 and the second connecting structures 423 are connected in alternating sequence. The shapes and sizes of these base sections could differ from the shapes and sizes of the first and second lateral sections. Fig. The basic sections were not shown in section 4a.

[0037] The number of first and second lateral spaces need not necessarily be the same, and each first lateral space 481 need not necessarily be aligned with a corresponding second lateral space 482. This is in Fig. Figure 4c shows that no second lateral gap on the first stator electrode is adjacent to the first lateral gap 481b on the rotor electrode. There are four first lateral sections 4111a–4111d, but three second lateral sections 4111a–4111c. The capacitance between the rotor electrode 411 and the first stator electrode 421 nevertheless increases as the rotor moves to the left and the overlap between the pairs 4111a + 4211a, 4111b + 4211b, and 4111c + 4211c increases. The additional first lateral section 4111d and the additional first lateral gap 481b remain fully aligned with the long second lateral section 4211 as the rotor moves to the left; therefore, they do not contribute to a change in capacitance. Fig. 4c also represents a device where the lateral offsets O1 and O2 of the two second lateral spaces 482a and 482b are not equal to the corresponding first lateral spaces 481a and 481c in the initial position.

[0038] Fig. Figure 5a represents a device wherein the rotor electrode further comprises two or more third lateral sections 5112 lying on a third lateral baseline 593. Each third lateral section 5112 is separated from the adjacent third lateral section 5112 on the third lateral baseline 593 by a third lateral space 583.

[0039] A second stator electrode 522 extends in the rotor-stator space from the edge of the stator 52 to the rotor 51. The rotor electrode 511 and the second stator electrode 522 are adjacent and essentially parallel to each other in the rotor-stator space.

[0040] The second stator electrode 522 is a meandering electrode having two or more fourth lateral sections 5221 lying on a fourth lateral baseline 594. Each fourth lateral section 5221 is separated from the adjacent fourth lateral section 5221 on the fourth lateral baseline 594 by a fourth lateral space 584. The second stator electrode is a folded beam with a serpentine shape.

[0041] The first lateral baseline 591 lies between the second lateral baseline 592 and the third lateral baseline 593. The third lateral baseline 593 lies between the first lateral baseline 591 and the fourth lateral baseline 594.

[0042] Every third lateral space 583 is adjacent to one of the fourth lateral spaces 584. Every third lateral space 583 is at least partially aligned with the fourth lateral space 584 in the transverse direction. The lateral widths of all third and fourth lateral spaces 583 / 584 are equal to the lateral widths of the first and second lateral spaces 581 / 582. The widths of all two or more first, second, third, and fourth second lateral sections 5111 / 5211 / 5112 / 5221 are also equal.

[0043] Each connection structure on the rotor electrode in Fig. 5a has two transverse sections, such as 5131, which are attached to the ends of the adjacent first lateral sections 5111. Each connection structure on the rotor electrode also has a third lateral section 5112, which extends between the two transverse sections 5131. The connection structures on the first stator electrode 521 can be the same as in Fig. 2a and similar connection structures could be used at the second stator electrode 522. Fig. However, 5a represents electrodes where the connection structures on the first and second stator electrodes have two transverse sections (such as 5231 and 5232) which are connected to each other by additional lateral sections (such as 5212 and 5222).

[0044] The lateral widths of these additional lateral sections can be equal to the lateral widths of the first, second, third, and fourth lateral sections. Furthermore, the transverse lengths of the transverse sections 5131, 5231, and 5232 can be equal to the lateral widths of all lateral sections. This results in the Fig. 5a shows a square meander structure where the spaces between all lateral sections have the same width.

[0045] As in Fig. 2a is every first lateral space 591 in Fig. 5a in the initial position is at least partially aligned with a second lateral space 582. Furthermore, every third lateral space 583 in the initial position is at least partially aligned with a fourth lateral space 584. Each of these alignments could be complete, as in Fig. 2c or Fig. 3c, or partially, as in Fig. 2a or Fig. 2c.

[0046] As before, in the case of partial alignment, each first lateral gap is 591 in Fig. 5a is laterally offset from the corresponding second lateral space 582 by the same lateral offset distance O. Furthermore, every third lateral space 583 can be laterally offset from the fourth lateral space 584 by the same lateral offset distance O. In full alignment, every third lateral space 583 is fully aligned with every fourth lateral space 584 in the initial position, and every first lateral space 581 is fully aligned with every second lateral space 582.

[0047] The part of the rotor / stator electrodes that is closest to the edge of the rotor / stator can be referred to as the base section, as mentioned above. Fig. 5a represents base sections 5113, 5213 and 5223, which are longer than the first (511), second (5211), third (5111) and fourth (5221) lateral section.

[0048] Fig. 5b represents an alternative configuration in which the lateral widths of the first (5111), second (5211), third (5111), and fourth (5221) lateral sections are all equal, but the transverse lengths of the transverse sections 5131, 5231, and 5232 are greater than the lateral widths of the lateral sections. This results in the rectangular meander structure shown in the figure. The in Fig. 5a and Fig. The embodiments shown in 5b could also be combined, for example, such that the transverse sections on the rotor electrode are longer than the transverse sections on the stator electrode or vice versa.

[0049] If the meandering structure of the first stator electrode 521 is aligned with the meandering structure of the second stator electrode 522 in the transverse direction, as shown in Fig. 5a and Fig. As shown in Figure 5b, both sides 5111 / 5112 of the meandering rotor electrode contribute to the main capacitance between the rotor and stator electrodes. Furthermore, the square or rectangular meandering structures shown in these figures represent part of the stray capacitance (the part or section corresponding to the capacitance arrows parallel to the y-axis in Figure 5b). Fig. 3) a linear dependence on the displacement. The number of rotor and stator electrodes could be further increased, and the meandering structure of all additional rotor and stator electrodes can be fully aligned in the transverse direction with the illustrated rotor and stator electrodes. Small offsets in the additional rotor / stator electrode meandering structures (with respect to the illustrated meandering structures) are also possible. In each embodiment of this disclosure, the microelectromechanical device can have a set of meandering rotor electrodes extending in the rotor-stator space from the edge of the rotor to the stator, and a corresponding set of meandering stator electrodes extending in the rotor-stator space from the edge of the stator to the rotor.

[0050] The set of meandering rotor electrodes can interlock with the set of meandering stator electrodes. The transverse spacing from each rotor electrode to the two adjacent stator electrodes can be the same. In other words, the transverse spacing between baselines 591 and 592 can be equal to the transverse spacing between baselines 593 and 594. Fig. 5a, and the baselines 595 and 596 may be separated by the same transverse distance from the baselines of the nearest rotor electrodes (which are not shown in the figure).

[0051] Alternatively, the rotor and stator electrodes can be organized in pairs, such that there is a first transverse distance from each rotor electrode to the stator electrode on one side (for example, to the electrode below it, i.e., the distance between 591 and 592 in Fig.5a) L1 is the first and second transverse distance from the same rotor electrode to the stator electrode on the other side (above it, i.e., the distance between 593 and 594) is L2. The distance L1 may differ from L2, but each rotor electrode may be separated from the adjacent stator electrodes by the same first and second transverse distances L1 and L2.

[0052] In all embodiments described in this disclosure, meandering rotor and stator electrodes comprise lateral sections separated by lateral gaps. In some embodiments, the lateral sections of the rotor electrode are partially aligned with the lateral sections of the stator electrode in the initial position, and their degree of alignment increases as the rotor is displaced. The capacitance between the rotor and stator electrodes also increases as a function of the displacement. In other embodiments, the lateral sections of the rotor electrode are fully aligned with the lateral sections of the stator electrode in the initial position, and their degree of alignment decreases as the rotor is displaced. The capacitance between the rotor and stator electrodes then also decreases as a function of the displacement.

Claims

[1] Microelectromechanical device comprising a mobile rotor (21) and a stationary stator (22) lying in a device plane defined by a lateral axis and a transverse axis, wherein the transverse axis is orthogonal to the lateral axis and the device has at least one measuring region, wherein an edge (219) of the rotor (21) and an edge (229) of the stator (22) are separated from each other by a rotor-stator space, and a rotor electrode (211) extends in the rotor-stator space from the edge (219) of the rotor (21) to the stator, and a first stator electrode extends in the rotor-stator space from the edge (229) of the stator (22) to the rotor (21), and the rotor electrode and the first stator electrode are adjacent and substantially parallel to each other in the rotor-stator space. wherein the rotor electrode (211) is a meandering electrode having two or more first lateral sections (2111a, 2111b) lying on a first lateral baseline (291), and each first lateral section is separated from the adjacent first lateral section on the first lateral baseline (291) by a first lateral space (281), wherein the rotor electrode is a folded beam having a serpentine shape, and the first stator electrode (221) is a meandering electrode having two or more second lateral sections (2211a, 2211b) lying on a second lateral baseline (292) and each second lateral section being separated from the adjacent second lateral section on the second lateral baseline (292) by a second lateral space (282), wherein the stator electrode is a folded beam having a serpentine shape, wherein at least a first lateral space (281) is adjacent to at least a second lateral space (282) and is at least partially aligned in the transverse direction with the at least a second lateral space (282), characterized by , that the at least one first lateral space (281) is partially and not completely aligned in the transverse direction with the at least one second lateral space (282) when the rotor (21) is in its initial position. [2] Microelectromechanical device according to claim 1, characterized by , that each first lateral space (281) and each second lateral space (282) have the same lateral width. [3] Microelectromechanical device according to one of claims 1 to 2, characterized by that each first lateral section and each second lateral section have the same lateral width. [4] Microelectromechanical device according to claim 3, characterized by , that the rotor electrode further comprises two or more third lateral sections (5112) lying on a third lateral baseline (593), and each third lateral section (5112) is separated from the adjacent third lateral section (5112) on the third lateral baseline (593) by a third lateral space (583), and a second stator electrode (522) extends in the rotor-stator space from the edge of the stator (52) to the rotor (51), such that the rotor electrode (511) and the second stator electrode (522) are adjacent and substantially parallel to each other in the rotor-stator space, and the second stator electrode (522) is a meandering electrode having two or more fourth lateral sections (5221) lying on a fourth lateral baseline (594), and each fourth lateral section is separated from the adjacent fourth lateral section on the fourth lateral baseline (594) by a fourth lateral space (584), wherein the second stator electrode (522) is a folded beam having a serpentine shape, and the first lateral baseline (591) lies between the second lateral baseline (592) and the third lateral baseline (593), and the third lateral baseline (593) lies between the first lateral baseline (591) and the fourth lateral baseline (594), wherein every third lateral space (583) is adjacent to one of the fourth lateral spaces and every third lateral space (583) is at least partially aligned with the fourth lateral space (584) in the transverse direction, and the lateral widths of all third and fourth lateral spaces are equal to the lateral widths of the first and second lateral spaces and the lateral widths of all two or more first, second, third and fourth second lateral sections are equal.

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