MEMS device with touch sensor element and proximity sensor element

Abstract

MEMS device (100), having the following features: at least one touch sensor element (120, 1201-1204) configured to detect a touch (124) piezoelectrically, capacitively, optically, or magnetically; and at least one proximity sensor element (130, 1301-1304) configured to detect an object (200) spaced from the proximity sensor element (130, 1301-1304) with sound (190, 191, 192); wherein the at least one touch sensor element (120, 1201-1204) and the at least one proximity sensor element (130, 1301-1304) are integrated on a semiconductor chip (110); wherein the at least one touch sensor element (120, 1201-1204) comprises a plate (142) defining a recess (140) in an insulator (114) and configured to be bent upon contact; and wherein the at least one touch sensor element (120, 1201-1204) is designed to detect a bending of the plate (142) caused by a touch piezoelectrically, capacitively, optically or magnetically, wherein the MEMS device (100) is configured to determine a force of contact based on a magnitude of the bending.

Description

Technical area

[0001] Embodiments according to the invention relate to a MEMS device with a touch sensor element and a proximity sensor element. Background of the invention

[0002] Tactile sensors have been developed for over 40 years. In the 1970s, Kinoshita et al. reported on piezoelectric sensing arrays to form a tactile system and implemented it on a robotic hand [1]. In 1980, Raibert et al. developed a tactile sensor array using conductive rubber and metal electrodes on the surface of an integrated circuit [2]. Around 1990, flexible and stretchable materials emerged as a new area of ​​interest [3-6]. Ohtsuka et al. described a piezoelectric tactile sensor for locating small invisible nodules in the lungs [7]. With the beginning of the 21st century, research and development efforts to mimic the tactile function of human skin expanded beyond pressure measurement to include temperature, humidity, hardness, viscosity, etc. [8-29]. In addition, the classification of materials and their properties, such as texture, shape, etc., has also been studied.using tactile sensors [30-34]. Engel et al. integrated a micromachined polymer tactile array with metal thin films to detect the hardness, thermal conductivity, temperature, and surface contours of a contact object

[35] . The functional principles of tactile sensors presented in the available literature are essentially classified as follows: I. Capacitive II. Piezoresistive III. Optical IV. Magnetic

[0003] For tactile sensors, primarily capacitive and piezoresistive, the use of dielectric layers and tactile bumps is common. The most common materials described for such contact bumps are PDMS, Pil2T-Si, PET, etc.

[0004] Ultrasonic ranging is the method of choice for today's numerous robotic systems due to its cost-effective implementation. Ultrasonic ranging technology measures distance by detecting the travel time of reflected waves from obstacles. The ultrasonic waves, typically between 20 kHz and 300 kHz, are generated and detected by the transducer. The transducer is the key component of the system, as it determines the overall performance. Most systems use piezoelectric transducers. In general, electrostatic transducers perform better than piezoelectric ones in this frequency range. The sensitivity of piezoelectric transducers is limited by the piezoelectric coupling coefficient.

[0005] Electrostatic or capacitive sensors typically consist of two horizontally positioned electrodes on the surface, which are subjected to a potential difference, thus creating an inhomogeneous electrostatic field. They typically detect the environment by detecting changes in the dielectric properties (e.g., by bringing an object close to it). This changes the electric field. Due to the inhomogeneity, the sensitivity increases with decreasing distance.

[0006] Capacitive micromachined ultrasonic transducers (CMUTs) are miniaturized electrostatic transducers with vertically positioned electrodes that transmit and receive ultrasonic waves electrostatically. The sensitivity of the CMUT is determined by the distance between the electrodes and is therefore a design parameter of the sensor. The sensor sensitivity does not change with decreasing object distance (but the sensor signal strength does). It has been shown that CMUTs can be used, for example, for distance detection in a robotic arm [36-41].

[0007] The use of miniaturized tactile and proximity sensors has been vividly reported in the available literature in the fields of medical technology, prosthetics, automotive, etc. [21, 42-44]. For example, capacitance- or ultrasound-based sensors have proven to be the most suitable. The capabilities embodied by such sensors in a robotic hand mimic the flexible, reactive grasping properties of the human hand. The handling of different object types (surface roughness, stiffness, etc.) and shapes defines the future of complex tasks regarding robotic handling technologies in the industrial sector. Furthermore, grasping is essential to provide automated support for medical services and care.Current and future applications arise from the extension of human sensory perception (augmented reality, prosthetics) and the implementation of a 3D object recognition and security system (fingerprint sensor) and depth-resolved gesture capture, which provide high information density in real time.

[0008] The article “Compliant Ultrasound Proximity Sensor for the Safe Operation of Human Friendly Robots Integrated with Tactile Sensing Capability” discloses the combination of an ultrasonic proximity sensor and a piezoelectric touch sensor in a PDMS structure.

[0009] The article “Development of a proximity sensor with vertically monolithic integrated inductive and capacitive sensing units” deals with capacitive and inductive proximity sensors.

[0010] The article “MEMS on robot applications” discloses touch sensors and proximity sensors that are applied separately to a robot hand.

[0011] The document WO 2017 / 196683 A1 discloses an ultrasonic transducer that operates with surface acoustic waves.

[0012] Current sensors aren't capable of combining a touch and a proximity sensor into a single solution. However, in the real world, tactile events are simply a logical next step when objects are close. Only system solutions attempt to address this issue, which is costly, bulky, and difficult to manage in close-distance situations.

[0013] In view of this, there is a need for a concept that enables simultaneous detection of touch and distance, cost-effective, simple and efficient manufacturing, and miniaturization of sensor arrays.

[0014] This object is solved by independent patent claim 1. Further developments according to the invention are defined in the subclaims. Summary of the invention

[0015] One embodiment of the present invention provides a MEMS device having at least one touch sensor element configured to detect a touch piezoelectrically, capacitively, optically, or magnetically, and having at least one proximity sensor element configured to detect an object spaced from the proximity sensor element using ultrasound. The at least one touch sensor element and the at least one proximity sensor element are integrated on a semiconductor chip. The at least one touch sensor element has a plate that defines a recess in an insulator and is configured to be bent upon touch. The at least one touch sensor element is configured to detect a bending of the plate caused by a touch piezoelectrically, capacitively, optically, or magnetically.The MEMS device is designed to determine a contact force based on the magnitude of the bending.

[0016] This embodiment of the MEMS device is based on the realization that by integrating the at least one touch sensor element and the at least one proximity sensor element (e.g., on the same substrate), both touches and objects in the vicinity of the MEMS device can be detected simultaneously. Furthermore, a spatially separated arrangement (e.g., the at least one touch sensor element is arranged next to the at least one proximity sensor element; e.g., arranged directly next to one another) of the at least one touch sensor element and the at least one proximity sensor element offers a high degree of design freedom, whereby, for example, a sensitivity of the at least one touch sensor element and / or the at least one proximity sensor element can be adjusted separately. This is not possible, for example, if proximity sensors and touch sensors are integrated into one and the same sensor element.In addition, the MEMS device eliminates the need to switch between touch and proximity mode, allowing for highly efficient control and readout. Another advantage is that the MEMS device can be miniaturized.

[0017] The sensor elements are electrical functional components that can be arranged, for example, on a substrate. A proximity sensor element can be designed to detect a distance of an object from the proximity sensor element, and a touch sensor element can be designed to detect a touch of the touch sensor element. The respective detection can be based on different functional principles of the sensor elements, and detected information (e.g., a distance for a proximity sensor element, e.g., a touch for a touch sensor element) can be read out from the sensor elements as an electrical signal. On the substrate on which the sensor elements are arranged, for example, additional conductor tracks and / or other components, such as control and / or readout electronics, can be arranged. The substrate thus serves, for example, as a carrier element without an electrical function.According to one embodiment, the semiconductor chip comprises the substrate.

[0018] According to one embodiment, the at least one touch sensor element is configured to be operated as a proximity sensor element in a proximity sensor mode. As a result, the at least one touch sensor element and the at least one proximity sensor element together can form a large proximity sensor. Even if touch sensor elements may not have the same precision or performance as special proximity sensor elements in the proximity sensor mode, a larger proximity-sensitive area can be formed with the sensor elements, thereby improving the precision of determining the distance between elements and the MEMS device or increasing the range, whereby even greater distances between elements and the MEMS device can be detected. Additionally or alternatively, the at least one proximity sensor element can be configured to be operated as a touch sensor element in a touch sensor mode.As a result, the at least one touch sensor element and the at least one proximity sensor element can together form a large touch sensor. In this case, a touch-sensitive area can be enlarged, which can, for example, improve the spatial precision of touch detection with the MEMS device.

[0019] If the MEMS device has a plurality of proximity sensor elements and / or a plurality of touch sensor elements, the MEMS device can be configured to operate individual or all proximity sensor elements in the touch sensor mode and / or to operate individual or all touch sensor elements in the proximity sensor mode. This allows various adjacent sensor elements to be grouped into large sensors. This allows proximity sensor elements and touch sensor elements to be interconnected to form a large proximity sensor in a first region of the semiconductor chip, and the proximity sensor elements and touch sensor elements to be interconnected to form a large touch sensor in a second region. Alternatively, all sensor elements of the MEMS device can be operated either in the proximity sensor mode or the touch sensor mode.According to one embodiment, the MEMS device is configured to adaptively adjust the mode in which the sensor elements are operated.

[0020] According to one embodiment, the at least one touch sensor element of the MEMS device comprises a plurality of touch sensor cells arranged in a one-dimensional array (e.g., touch sensor cells arranged in a row) or two-dimensional array (e.g., touch sensor cells arranged in an area). In other words, a plurality, for example, at least two, touch sensor cells are combined to form one touch sensor element. Additionally or alternatively, the at least one proximity sensor element comprises a plurality of proximity sensor cells arranged in a one-dimensional array (e.g., proximity sensor cells arranged in a row) or two-dimensional array (e.g., proximity sensor cells arranged in an area). In other words, a plurality, for example, at least two, proximity sensor cells are combined to form one proximity sensor element.The arrangement of touch sensor cells and / or proximity sensor cells in the respective sensor element enables individual grouping of the sensor cells. This allows the at least one touch sensor element and the at least one proximity sensor element to be designed differently from one another, e.g., in terms of shape, surface area, sensitivity, etc. The arrangement of the respective sensor cells (e.g., the proximity sensor cells or the touch sensor cells) in a one-dimensional or two-dimensional field also enables the detection of a touch and / or approach of an object to the MEMS device with high spatial resolution. The advantages thus lie, among other things, in the design freedom of the respective sensor elements with regard to, for example, sensitivity and the visual / two-dimensional representation of the touch and the distance.

[0021] According to one embodiment, the touch sensor cells, i.e. the electrical transducers, of the at least one touch sensor element are electrically connected in parallel in order to be controlled and read out in parallel. Additionally or alternatively, the proximity sensor cells, i.e. the electrical transducers, of the at least one proximity sensor element are electrically connected in parallel in order to be controlled and read out in parallel. This allows, for example, each individual sensor cell of a sensor element to be controlled and read out separately. In addition, a possible failure of individual sensor cells can be compensated for by neighboring sensor cells, i.e. individual defective sensor cells can be compensated for. The parallel connection enables very efficient control and readout.

[0022] According to one embodiment, the touch sensor cells of the at least one touch sensor element and / or the proximity sensor cells of the at least one proximity sensor element are round. This enables miniaturization of the MEMS device, as the sensor cells can be arranged very close to one another (e.g., an overlap of adjacent sensor rows is possible), thus achieving significant space savings. The round shape is advantageous in some applications, as the symmetry has a homogeneous radiation characteristic. Alternatively, rectangular and / or hexagonal shapes are also conceivable. Depending on the desired arrangement of the sensor cells or the area of ​​application of the MEMS device, other shapes of the sensor cells may be advantageous. Here, it may also be advantageous if the touch sensor cells have a different shape than the proximity sensor cells. The sensor cells can, for example,Have electrodes made of, for example, amorphous material.

[0023] According to one embodiment, the touch sensor cells of the at least one touch sensor element and / or the proximity sensor cells of the at least one proximity sensor element are arranged in rows. Adjacent rows are arranged offset from one another such that the adjacent rows at least partially overlap without adjacent touch sensor cells and / or adjacent proximity sensor cells overlapping. This enables advantageous interleaving of sensor cells of adjacent rows, as this saves space, among other things, and thus enables miniaturization of the MEMS device. In addition, increased local sensitivity is achieved, for example, since no non-sensitive boundary is created between two sensor rows.

[0024] According to one embodiment, the MEMS device has a plurality of touch sensor elements and proximity sensor elements arranged next to one another in a plane. This allows a large area to be realized for detecting touches and objects in the vicinity of the MEMS device. This enables touches and nearby objects to be detected at multiple positions in the plane. In an advantageous embodiment, the touch sensor elements and proximity sensor elements can always be arranged alternately within a row in order to thereby realize touch and proximity detection with high spatial resolution. These rows can be arranged offset from one another or adjacent to one another. The offset arrangement of the rows allows for high spatial resolution.If the rows are not offset from one another, the effective sensitive area of ​​the touch sensor elements and / or proximity sensor elements can be increased. The size of the respective sensor elements or the effective sensitive area (e.g., for touch detection and proximity detection separately) determines the sensitivity. In proximity sensor cells (e.g., when using CMUTs or PMUTs; e.g., for ultrasound), the structure width, for example, is still decisive for the formation of the sound field. The extension can optionally be selected according to the emitted wavelength. Typically, a characteristic extension (e.g., 0.5 to 1.0 of the wavelength) is selected here.

[0025] According to one embodiment, the at least one proximity sensor element comprises at least one micromechanical ultrasonic transducer. The micromechanical ultrasonic transducer can represent a proximity sensor cell of the proximity sensor element.

[0026] According to one embodiment, the micromechanical ultrasonic transducer is designed as a capacitive micromechanical ultrasonic transducer or as a piezoelectric micromechanical ultrasonic transducer. The capacitive micromechanical ultrasonic transducer is designed, for example, to capacitively detect an ultrasonic echo of an object in the vicinity of the proximity sensor cell. The piezoelectric micromechanical ultrasonic transducer is designed, for example, to piezoelectrically detect an ultrasonic echo of an object in the vicinity of the proximity sensor cell. The MEMS device can be configured to determine a distance of the object, a material composition of the object, and / or a surface texture of the object based on the detected ultrasonic echo.

[0027] According to one embodiment, the capacitive micromechanical ultrasonic transducer comprises a drive circuit configured to excite a movable electrode of the capacitive micromechanical ultrasonic transducer by means of an electrostatic force between the movable electrode and a fixed electrode of the capacitive micromechanical ultrasonic transducer in order to emit ultrasound. Additionally, the capacitive micromechanical ultrasonic transducer comprises a readout circuit configured to read out a change in distance (e.g., a change in capacitance) between the movable electrode, which is deflected by an ultrasonic echo reflected from the spaced-apart object, and the fixed electrode. "Readout," for example, is the displacement current that arises when the distances between the electrodes change.The piezoelectric micromechanical ultrasonic transducer has a control circuit designed to control a deformation of a layer stack, which has a piezoelectric layer, of the piezoelectric micromechanical ultrasonic transducer in order to thus emit ultrasound. Furthermore, the piezoelectric micromechanical ultrasonic transducer has a readout circuit designed to read out a deformation of the layer stack based on an ultrasonic echo reflected from the spaced-off object. The piezoelectric micromechanical ultrasonic transducer has the layer stack as a sound-emitting element. The layer stack has, for example, a first electrode material, a piezoelectric material, and a second electrode material. If the piezoelectric micromechanical ultrasonic transducer is a ceramic piezo transducer, the layer stack can have a layer sequence with a first electrode (e.g.B. lower electrode), a piezoelectric layer comprising PZT material, and a second electrode (e.g. upper electrode). The ceramic piezo transducer is a thickness oscillator. In other words, the deformation of this layer stack involves a deflection of the layer stack in the thickness direction of the individual layers. If the piezoelectric micromechanical ultrasonic transducer has piezoelectric thin or thick layers, the layer stack can be constructed analogously to the layer stack of the ceramic piezo transducer. In this case, it can also be a thickness oscillator. If the piezoelectric micromechanical ultrasonic transducer is a PMUT, the layer stack can represent a clamped membrane with a layer sequence comprising a first electrode (e.g. lower electrode), a piezoelectric layer with piezo material, and a second electrode (e.g. upper electrode).The PMUT is a membrane transducer. PMUTs detect the deformation of the layer stack (the membrane). The PMUT is not a so-called thickness transducer, where deformation in one direction leads to sound emission in the same direction. Rather, the PMUT membrane is clamped (e.g., in an xy plane). Expansion in this plane is therefore prevented, leading to deformation in the z direction.

[0028] According to one embodiment, a piezoelectric thickness oscillator utilizes the so-called d33 coefficient of the piezoelectric material: An electric field in the z-direction directly leads to an expansion in the z-direction. For example, a piezoelectric membrane oscillator utilizes the d31 coefficient of the piezoelectric material: An electric field in the z-direction directly leads to an expansion in the xy-plane. The clamping causes the membrane to deform in the z-direction.

[0029] According to one embodiment, the at least one touch sensor element comprises at least one micromechanical sensor structure. The micromechanical sensor structure can represent a touch sensor cell of the touch sensor element.

[0030] According to one embodiment, the micromechanical sensor structure comprises a readout circuit configured to read out a changed resonant frequency of a movable electrode of the micromechanical sensor structure or of a layer stack of the micromechanical sensor structure. The changed resonant frequency is based on a changed load on the movable electrode of the micromechanical sensor structure or on a changed load on the layer stack (142) of the micromechanical sensor structure due to a touch.

[0031] According to one embodiment, the micromechanical sensor structure comprises a capacitive micromechanical sensor structure or a piezoelectric micromechanical sensor structure. The capacitive micromechanical sensor structure is configured, for example, to detect a touch capacitively. The piezoelectric micromechanical sensor structure is configured, for example, to detect a touch piezoelectrically. Optionally, a capacitive or piezoelectric drive / readout structure can be used in the capacitive micromechanical sensor structure or in the piezoelectric micromechanical sensor structure, which can serve as an ultrasonic transducer.

[0032] According to one embodiment, the capacitive micromechanical sensor structure has a readout circuit designed to read out a change in distance (e.g., a change in capacitance) between a movable electrode of the capacitive micromechanical sensor structure and a fixed electrode of the capacitive micromechanical sensor structure, wherein the movable electrode is deflected by means of a touch in order to cause the change in distance (e.g., a change in capacitance). "Read out," for example, is the displacement current that arises when the distances between the electrodes change. The piezoelectric micromechanical sensor structure has a readout circuit designed to read out a deformation of a layer stack, which has a piezoelectric layer, of the piezoelectric micromechanical sensor structure. The deformation of the layer stack is based on a touch of the layer stack. The layer stack has, for example,a first electrode material, a piezoelectric material, and a second electrode material. If the piezoelectric micromechanical sensor structure is a ceramic piezoelectric transducer, the layer stack can have a layer sequence with a first electrode (e.g., lower electrode), a piezoelectric layer comprising, for example, PZT material, and a second electrode (e.g., upper electrode). If the piezoelectric micromechanical sensor structure has piezoelectric thin or thick films, the layer stack can be constructed analogously to the layer stack of the ceramic piezoelectric transducer. Alternatively, the layer stack of the piezoelectric micromechanical sensor structure can have a clamped membrane with a layer sequence with a first electrode (e.g., lower electrode), a piezoelectric layer with piezo material, and a second electrode (e.g., upper electrode).A layer stack may further consist of a plurality of alternating electrodes and piezoelectric materials, wherein the first layer and the last layer are formed by electrodes.

[0033] According to one embodiment, a load transfer element is arranged above the at least one touch sensor element. This allows the force of a touch to be optimally transferred to the touch sensor element. The load transfer element, for example, enables not only the touch to be detected but also a measurement of a force and / or pressure transmitted by the touch. The load transfer element can be arranged above several adjacent touch sensor cells or above individual touch sensor cells (a touch sensor element then has, for example, several load transfer elements). The load transfer element can also serve as a protective layer.

[0034] According to one embodiment, a protective layer is arranged over the at least one proximity sensor element. The protective layer can be a thin layer to protect the at least one proximity sensor element from external influences, such as contact and contamination.

[0035] According to one embodiment, the protective layer of the proximity sensor element and the load transmission element of the touch sensor element can be identically formed or at least have the same material and / or the same 3D shape.

[0036] According to one embodiment, a continuous universal layer is arranged over both the touch sensor elements and the proximity sensor elements, wherein the continuous universal layer acts as a load transfer element over the touch sensor elements and acts as a protective layer over the proximity sensor elements.

[0037] According to one embodiment, a protective layer is arranged over the at least one proximity sensor element and / or a load transmission element is arranged over the at least one touch sensor element, wherein the load transmission element and / or the protective layer are cubic, cuboid, pyramid-shaped, or hemispherical. The advantages of these shapes lie in increased force transmission and thus a different sensitivity and a lower influence on neighboring touch and / or proximity elements. Furthermore, these configurations influence the adhesion properties on the sensor surface differently. This is relevant for applications, e.g., in a robot gripper for the secure / tactile gripping of objects.

[0038] According to one embodiment, a protective layer is arranged over the at least one proximity sensor element, and / or a load transfer element is arranged over the at least one touch sensor element, wherein the load transfer element and / or the protective layer comprises polymer material, elastomer material, or a comparable material. These materials exhibit excellent load transfer and are robust against environmental influences. Furthermore, these materials are suitable for conducting ultrasonic waves.

[0039] According to one embodiment, a protective layer is arranged above the at least one proximity sensor element, and a load transmission element is arranged above the at least one touch sensor element, the protective layer having a smaller thickness than the load transmission element. This ensures that the proximity sensor elements are very well separated from the touch sensor elements, providing additional protection for the proximity sensor elements, as contact with them can be prevented, for example. Large objects, for example, are kept at a distance from the proximity sensor elements by the raised load transmission elements if the object is too large to fit into a gap between two load transmission elements arranged adjacent to the proximity sensor element. The small thickness of the protective layer also ensures that ultrasonic waves are only slightly attenuated, or not at all.

[0040] According to one embodiment, a protective layer is arranged over the at least one touch sensor element, and the touch sensor element has at least one MEMS ultrasonic transducer for transmitting and / or receiving sound waves. In touch mode, this can be used to determine information about the touching object / person, etc. This information can include: topology, 3D images of the object, and material parameters for classifying the object.

[0041] According to one embodiment, the semiconductor chip comprises a flexible substrate. This not only allows the MEMS device to be used in a planar manner in various applications, but also allows the MEMS device to adapt to curved or irregular surfaces. Short character description

[0042] Embodiments according to the present invention are explained in more detail below with reference to the accompanying figures. With regard to the schematic figures shown, it should be noted that the illustrated functional blocks are to be understood both as elements or features of the device according to the invention and as corresponding method steps of the method according to the invention, and corresponding method steps of the method according to the invention can also be derived therefrom. They show: Fig. 1 is a schematic diagram of a MEMS device according to an embodiment of the present invention; Fig. 2a is a schematic diagram of a MEMS device with a sealed proximity sensor element, according to an embodiment of the present invention; Fig. 2b is a schematic diagram of a MEMS device with a vented proximity sensor element, according to an embodiment of the present invention; Fig. 2c is a schematic diagram of a MEMS device with an electrode embedded in an insulator and a sealed proximity sensor element, according to an embodiment of the present invention; Fig. 2d is a schematic diagram of a MEMS device with an electrode embedded in an insulator and a vented proximity sensor element, according to an embodiment of the present invention; Fig. 3a is a schematic diagram of a MEMS device having a plurality of touch sensor elements and proximity sensor elements according to an embodiment of the present invention; Fig. 3b is a schematic section of a MEMS device having a plurality of touch sensor elements and proximity sensor elements according to an embodiment of the present invention; Fig. 4a is a schematic representation of a circuit of a MEMS device in a first view, according to an embodiment of the present invention; Fig. 4b is a schematic representation of a circuit of a MEMS device in a second view, according to an embodiment of the present invention; Fig. 5a is a schematic representation of a MEMS device in which, according to an embodiment of the present invention, a load transfer element is arranged above at least one touch sensor element; Fig. 5b is a schematic representation of a MEMS device in which, according to an embodiment of the present invention, a protective layer is arranged over at least one proximity sensor element; Fig. 5c is a schematic representation of a MEMS device in which, according to an embodiment of the present invention, at least one load transfer element over at least one touch sensor element and at least one protective layer over at least one proximity sensor element have the same thickness; Fig. 6a is a schematic diagram of a control circuit for a sensor element of a MEMS device, according to an embodiment of the present invention; Fig. 6b is a schematic diagram of a drive circuit, without bias tee, for a sensor element of a MEMS device, according to an embodiment of the present invention; Fig. 7a is a schematic diagram of a readout circuit for a sensor element of a MEMS device, according to an embodiment of the present invention; Fig. 7b is a schematic representation of a readout circuit, without bias tee, for a sensor element of a MEMS device, according to an embodiment of the present invention; and Fig. 8 is a block diagram of a system configuration of a MEMS device according to an embodiment of the present invention. Detailed description of the embodiments according to the figures

[0043] Before exemplary embodiments of the present invention are explained in more detail below with reference to the drawings, it is pointed out that identical, functionally identical or equivalent elements, objects and / or structures in the different figures are provided with the same or similar reference numerals, so that the description of these elements shown in different exemplary embodiments is interchangeable or can be applied to one another.

[0044] Fig. 1 shows a schematic representation of a MEMS device 100, comprising a touch sensor element 120 configured to detect a touch 124 piezoelectrically, capacitively, optically, or magnetically, and at least one proximity sensor element 130 configured to detect an object 200 spaced from the proximity sensor element 130 using sound 191, such as ultrasound and audible sound. The at least one touch sensor element 120 and the at least one proximity sensor element 130 are integrated on a semiconductor chip 110.

[0045] According to one embodiment, MEMS device 100 may be referred to as a system, MEMS system, sensor module, MEMS sensor module, integrated sensor, or integrated tactile and proximity sensor. Based on the features of MEMS device 100 described herein, a method for its fabrication may be derived. Hereinafter, touch sensor elements 120 may also be referred to as tactile sensor elements, and proximity sensor elements 130 may also be referred to as proximity sensor elements.

[0046] In the Fig. 2a to 2d each show a MEMS device 100 with a touch sensor element 120 and a proximity sensor element 130. Both the touch sensor element 120 and the proximity sensor element 130 are integrated on a semiconductor chip 110. The semiconductor chip 110 includes, for example, a wafer 112 and an insulator 114. The insulator 114 may be a layer stack of insulators. Alternatively, the insulator 114 is formed from a single insulating layer. According to one embodiment, the insulator 114 includes at least one recess 140 in a region of the touch sensor element 120 and / or in a region of the proximity sensor element 130. The recess 140, for example a cutout, is formed on a surface of the insulator 114 facing away from the wafer 112.

[0047] The at least one recess 140 is bounded, for example, on one side by a plate 142, wherein the plate 142 can alternatively be referred to as a membrane or a movable plate. The plate 142 is connected, for example, at its ends to the insulator 114 and arranged between these ends so as to be suspended above the recess 140. According to one embodiment, the plate 142 can be designed as a layer stack and have several conductive and / or non-conductive layers. Even if in the Fig. 2a to 2d all plates 142 are shown to have the same thickness (e.g., the same extent in the z-direction; e.g., an extent perpendicular to a surface of the insulator 114 adjacent to the plate 142), the plate 142 of the touch sensor element 120 may have a different thickness than a thickness of the plate 142 of the proximity sensor element 130. According to one embodiment, the recess 140 and / or the plate 142 is cylindrical, cuboidal, or cubic in shape.

[0048] According to one embodiment, the recess 140 of the touch sensor element 120 is hermetically or vacuum-tightly sealed (e.g., hermetically or vacuum-tightly sealed (vacuum sealed)) by means of the plate 142 and the insulator 114, as shown, for example, in the Fig. 2a to 2d.

[0049] According to one embodiment, the recess 140 of the proximity sensor element 130 is hermetically or vacuum-tightly sealed (e.g., hermetically or vacuum-tightly sealed (vacuum sealed)) by means of the plate 142 and the insulator 114 (see, e.g., Fig. 2a or Fig. 2c). Alternatively, the plate 142 of the proximity sensor element 130 may have openings (e.g., holes) through which the recess 140 can be ventilated or vented (see Fig. 2b or Fig. 2d).

[0050] According to one embodiment, a load transfer element 150 is arranged on the plate 142 and / or on the insulator 114 of the touch sensor element 120. The load transfer element 150 is arranged, for example, on a side of the plate 142 facing away from the recess 140. Alternatively or additionally, the load transfer element 150 can be arranged, for example, on a surface of the insulator 114 on which the plate 142 is also arranged. The load transfer element 150 increases the sensitivity of the touch sensor element 120. The load transfer element 150 (e.g., a bump elastomer) comprises, for example, an elastomer material. According to one embodiment, the load transfer element 150 has features and / or functionalities of the Fig. 5a to 5c described load transmission element 150.

[0051] In other words, the Fig. 2a to 2d Variations or cell configurations with a representation of a sensor module in which each cell, ie each sensor element 120 / 130, can be used separately as a tactile or distance sensor.

[0052] The sensor elements 120 / 130 can be controlled and read using a physical operating principle, such as electrostatic, piezoelectric, optical, magnetic, etc. The MEMS device can have sensor elements with different physical operating principles.

[0053] In the case of a piezoelectric MEMS (e.g. PMUT), the plate 142, according to Fig. 2a or Fig. 2b, a layer sequence of at least one electrically conductive material, a piezoelectric material, and another electrically conductive material, i.e., the plate 142 is formed from a layer stack of at least one electrode, a piezoelectric layer, and an electrode, in this order. Additional layers can also be arranged between the layers just mentioned, such as one of the electrodes and the piezoelectric layer. The piezoelectric MEMS can be understood, for example, as a piezoelectric micromechanical ultrasonic transducer (PMUT), e.g., in the case of the proximity sensor element 130, and / or a piezoelectric micromechanical sensor structure, e.g., in the case of the touch sensor element 120. In piezoelectric touch sensor elements 120, a deformation of the plate 142 is evaluated by the piezoelectric effect in the layer stack.In piezoelectric proximity sensor elements 130, ultrasound is transmitted and received by the piezoelectric effect in the layer stack.

[0054] The Fig. 2c and Fig. 2d show embodiments of a capacitive MEMS. In this case, a layer 144 of electrically conductive material, e.g., a fixed electrode, is integrated or embedded in the insulator 114, for example, below the recess 140. The region of the insulator 114 above the layer 144 of electrically conductive material, e.g., the region facing the plate 142, can be structured. Thus, the insulation layer can, for example, only cover the electrode 144 in places. Because the layer 144 is at least partially covered with an insulation layer of the insulator 114, a short circuit with the movable plate 142 can be avoided.

[0055] The capacitive sensor elements 120 / 130 have two electrodes, the layer 144 and the plate 142 (e.g., an electrode and optionally insulating layers), and at least one dielectric between them. In capacitive touch sensor elements 120, a deformation of the plate 142 can be evaluated through the electrostatic interaction between the electrodes. In capacitive proximity sensor elements 130, ultrasound can be transmitted and received through the electrostatic interaction.

[0056] The capacitive MEMS can be understood as, for example, a capacitive micromechanical ultrasonic transducer (CMUT), e.g., in the case of the proximity sensor element 130, and / or a capacitive micromechanical sensor structure, e.g., in the case of the touch sensor element 120.

[0057] CMUTs are fundamentally MEMS structures consisting of two opposing electrodes. One of the electrodes is rigid, e.g., layer 144, and the other is movable, e.g., plate 142. Between the two electrodes is an insulating layer and a gap 140, which is sealed, e.g., in a vacuum. CMUTs can both transmit and receive by converting electrical energy into acoustic energy or vice versa by moving the movable electrode 142. When the CMUT is used as a sound transmitter, an electrical potential is built up between the two electrodes 142, causing an electrostatic force to deflect the movable electrode 142 (e.g., first electrode) toward the rigid electrode 144 (e.g., second electrode). This movement generates a sound wave (e.g., an ultrasonic wave). Conversely, CMUTs can also act as receivers when an acoustic input signal (e.g., an ultrasonic wave) acts on the movable electrode 142.This triggers a movement of electrode 142, which in turn causes a current, e.g., a displacement current, to flow between the two electrodes. This electrical current can be measured and, for example, digitally processed into an image for further analysis.

[0058] The proximity sensor element 130 of the MEMS device 100 comprises, for example, at least one micromechanical ultrasonic transducer. This can be, for example, a capacitive micromechanical ultrasonic transducer or a piezoelectric micromechanical ultrasonic transducer.

[0059] Proximity sensor elements 130 and / or touch sensor elements 120, according to one of the Fig. 2a to 2d, a drive circuit 170, as described in connection with Fig. 6a or Fig. 6b, and a readout circuit 180, as described in connection with the Fig. 7a and Fig. 7b. However, alternative control and readout circuits are also conceivable.

[0060] In a proximity sensor element 130, the plate 142 is set into a transmit vibration, for example, by means of the control circuit in order to emit ultrasound. An ultrasonic echo reflected from a distant object sets the plate 142 into a receive vibration, and this receive vibration is detected by the readout circuit. Thus, the distance of the object to the proximity sensor can be determined, for example, using ultrasonic time-of-flight measurements. According to one embodiment, the proximity sensor element 130 is designed to detect the receive vibration capacitively, piezoelectrically, optically, or magnetically. The detection of the receive vibration can be carried out, for example, as described below (e.g., the same as or similar to detecting a bending of the plate 142 caused by a touch).

[0061] According to one embodiment, the plate 142 of the touch sensor element 120 is bent upon touch. The touch sensor element 120 has, for example, a readout circuit to detect this bending. Based on the strength of the bending, a touch force can be determined, for example. According to one embodiment, the touch sensor element 120 is configured to detect the bending capacitively, piezoelectrically, optically, or magnetically.

[0062] A bending of the plate 142 can be detected in a variety of ways, as explained below. However, the methods presented should not be considered limiting, as other methods are also conceivable.

[0063] According to one embodiment, the plate 142 and an additional electrode (e.g., counter electrode, e.g., second electrode) form a capacitor. In this case, the plate 142 represents, for example, a first electrode or has a first electrode. The bending of the plate 142 changes the capacitance of the capacitor, which can be read out by the readout circuit. In other words, for example, the displacement current that arises when the distances between the electrodes change is read out, or an electrostatic interaction is evaluated. The additional electrode is, for example, embedded in the insulator 114, as shown in the Fig. 2c and Fig. 2d as layer 144. The wafer 112 or the insulator 114 can be implanted to create an electrode in the wafer substrate or in the insulator 114.

[0064] According to one embodiment, the plate 142 has a layer stack consisting of at least a first electrode, a piezoelectric layer, and a second electrode. The first electrode and the second electrode are arranged, for example, on two opposite sides (e.g., on a side facing the recess 140 and on a side facing away from the recess 140) of the piezoelectric layer. The bending changes an electrical voltage between the two electrodes on the piezoelectric layer, which can be read out by the readout circuit. In the case of a proximity sensor element, a voltage can be applied to the two electrodes, for example, by means of the drive circuit, in order to cause the plate 142 to oscillate in transmission.

[0065] According to one embodiment, a laser and a detector are arranged in the recess 140 or in the insulator 114 (e.g., facing the recess via an opening). The laser is directed at the plate 142 and is reflected from the plate to the detector. This enables optical detection of the bending of the plate 142.

[0066] According to one embodiment, the plate 142 and / or the substrate comprises a permanent magnet or at least one electromagnet (e.g., a flat coil - see source

[16] ). A dynamic magnetic field of the electromagnet results in a force acting on the membrane, which, for example, contains a permanent magnet or second electromagnet, and thus in sound emission. Conversely, the movement of the membrane leads to a changed magnetic field in the coil of the electromagnet, which induces a corresponding alternating voltage.

[0067] Alternatively, the membrane can be made of magnetoresistive or magnetoelastic materials. A coil arrangement below the recess 140 or on the membrane itself can generate a variable magnetic field and thus (similar to the piezoelectric effect) induce a deformation of the membrane or, conversely, detect it by means of induction.

[0068] According to one embodiment, the touch sensor cell 122 is a micromechanical sensor structure having a readout circuit configured to read out a changed resonant frequency of a movable electrode of the micromechanical sensor structure or of a layer stack of the micromechanical sensor structure. The changed resonant frequency is based on a changed load on the movable electrode of the micromechanical sensor structure or on a changed load on the layer stack of the micromechanical sensor structure due to a touch. For example, the plate 142 can represent the movable electrode in a capacitive micromechanical sensor structure and the layer stack in a piezoelectric micromechanical sensor structure.As described above, the plate may also be designed differently in other micromechanical sensor structures, such as a laser-based micromechanical sensor structure or a magnetic micromechanical sensor structure, but the respective readout circuit may also be designed to read out a changed resonance frequency of the plate 142.

[0069] In the Fig. 3a to 5c schematically illustrate touch sensor elements 120 having a plurality of touch sensor cells 122 and proximity sensor elements 130 having a plurality of proximity sensor cells 132. Each touch sensor cell 122 may, for example, have the same or a similar structure as the device shown in one of the Fig. 2a to 2d and each proximity sensor cell 132 may, for example, have the same or a similar structure as the one described in one of the Fig. 2a to 2d described proximity sensor element 130. In other words, the proximity sensor element 130 shown in one of the Fig. 2a to 2d also a touch sensor cell 120 (e.g. a tactile cell) in the sense of the Fig. 3a to 5c and which in one of the Fig. 2a to 2d may also be a proximity sensor cell 132 (e.g. a distance cell) in the sense of the Fig. 3a to 5c. Alternatively, the touch sensor cells 122 and / or the proximity sensor cells 132 may be other known sensors.

[0070] According to one embodiment, the MEMS device 100 makes it possible to integrate multiple tactile and distance sensor elements (e.g., touch sensor elements 120 and proximity sensor elements 130), e.g., based on a capacitive transducer, in a single chip (see, e.g., Fig. 3a to Fig. 5c). Using sensor fusion, high-volume information about distance and touch can be captured and processed. These advantages can be achieved with the technology, devices, and manufacturing methods described herein for an on-chip distance and touch sensor system. The technology for integrating the integrated system (e.g., the MEMS device) based on a capacitive transducer can vary, and some examples include a sacrificial release process, wafer bonding, or other methods. It is implied that any other technology used to manufacture such transducers, sensors, and integrated sensors is also implied. The entire system (e.g., MEMS device 100), separate sensor elements (e.g., touch sensor elements 120 and / or proximity sensor elements 130), each transducer cell (e.g., touch sensor cells 122 and / or proximity sensor cells 132), etc.can be operated with discrete electronics, with an application specific integrated circuit (ASIC) and even a combination of both (see e.g. . Fig. 4a or Fig. 4b).

[0071] According to one embodiment, it is implied that each transducer cell (e.g., touch sensor cells 122 and / or proximity sensor cells 132), each transducer element (e.g., touch sensor elements 120 and / or proximity sensor elements 130), or the entire transducer (e.g., MEMS device 100) can act as both a tactile and a proximity sensor, depending on the array configuration and drive modality (e.g., drive circuitry). Depending on these different capabilities, a few sensor modules may be used. According to one embodiment, the MEMS device (e.g., an integrated proximity and tactile sensor module) has at least one of the following features: I. Each cell (e.g., touch sensor cells 122 and / or proximity sensor cells 132) is used (e.g., driven or controlled) as either a tactile or a proximity sensor. II. Alternating cells are used either as a distance sensor or as a tactile sensor (e.g., driven or triggered). III. A transducer element (comprising a plurality of electrically bundled cells) can be used (e.g., driven or triggered) as a tactile or a distance sensor. IV. Separate tactile and proximity sensor elements may be mechanically configured together to form the entire sensor module. V. Integrated manufacturing processes (sacrificial release technology, wafer bonding, etc.) may be used to fabricate the sensing (cell or elements) and / or spacing (cell or elements) sensor modules to form the overall sensor assembly (e.g., MEMS device 100). VI. Geometric structures (cubic, rectangular, pyramidal, etc.) made on an upper tactile sensor (cells or elements) made of materials (including all soft materials such as polymer, elastomer, etc. and material suitable for such structures and applications) capable of coupling the tactile load with the respective sensor of the same (cell or element) can be used as tactile load bumps (e.g., load transfer elements). VII. A proximity sensor (cell or elements) may have either a bare surface or structures (e.g., a protective layer) geometrically and materially similar to the tactile load bumps may be used to cover them to protect them from mechanical impacts or damage during operation. VIII. Capacitive transducers (including all types such as CMUT) can be used in various configurations, including hermetically sealed, vented, or vacuum sealed, depending on the requirements for tactile or distance modes. This implies, for example, the integration of immersion and airborne capacitive transducers on a single chip.

[0072] The integrated sensor module described herein, the MEMS device 100, has numerous features / advantages: - Miniaturization - Associated resource savings and cost reduction for large quantities - Integration of electronics (ADC, signal processing, etc.) possible. - Design freedom and scalability of size. - Potential flexibility arises from both the geometry and operational perspective as: • e.g. integrated or separate production of sensors (tactile and distance sensors; cells and elements) from flexible substrates. • e.g. arrangement of separate sensors (cells or assemblies) on a flexible carrier (e.g. flexible substrate). • e.g. use of a tactile sensor, distance sensor (elements or cells) in a separate or aggregated configuration either individually or by multiplexing.

[0073] In the Fig. 3a to 5c are schematic representations of configurations in which grouped transducer cells (e.g., touch sensor cells 122 and / or proximity sensor cells 132) form sensor elements (e.g., touch sensor elements 120 and / or proximity sensor elements 130) and alternating elements are arranged, e.g., in a checkered pattern, to form the complete sensor module (e.g., the MEMS device). The tactile elements (touch sensor elements 120) are covered, for example, with an elastomeric contact bump (e.g., a load transfer element) (see, e.g., Fig. 5a to Fig. 5c). The distance elements (proximity sensor elements 130) can have, for example, three configurations in this state: 1. Bare surface (see e.g. Fig. 5a) 2. Covered to protect against mechanical contact or damage (e.g. protective layer): 2.1. Part thickness compared to tactile load height. (See e.g. Fig. 5b) 2.2. Equal thickness compared to the tactile load height. (see e.g. Fig. 5c)

[0074] The present invention relates to a device and a system for tactile and distance detection using an integrated sensor module, e.g., based on a MEMS acoustic transducer. In particular, it is a system in which, for the first time, multiple tactile and distance sensor elements have been integrated, e.g., for integration on a robot hand.

[0075] Through sensor fusion of the individual systems, the acquisition and processing of a high information density, which is required with increasing complexity of applications, can be achieved.

[0076] Fig. 3a shows an element layout on a chip. According to one embodiment, the entire chip (e.g., the semiconductor chip) consists of 8 tactile (e.g., touch sensor elements 120) and 8 spacer elements (e.g., proximity sensor elements 130) arranged next to one another in a plane. For clarity, the first touch sensor element 1201 and the first proximity sensor element 1301 have been outlined in dashed lines. Each touch sensor element 120 has, for example, a plurality of touch sensor cells 122 arranged in a two-dimensional array, and each proximity sensor element 130 has, for example, a plurality of proximity sensor cells 132 arranged in a two-dimensional array. The touch sensor cells 122 and / or the proximity sensor cells 132 are, for example, round.

[0077] Furthermore, each touch sensor element 120 and each proximity sensor element 130 has contacts 160 and 162, i.e., contact points or contact pads. The contact 162 serves, for example, to transmit the transmit voltage or for detection in the receive path, and the contact 160 can represent a ground connection, a DC connection, or the like. According to one embodiment, the contact points 160 associated with the touch sensor elements 120 and / or the proximity sensor elements 130 can also be implemented together. Optionally, this combination can also be applied to the contacts 162. An advantageous circuit is shown in Fig. 4a and Fig. 4b (e.g., a parallel connection of the touch sensor cells 122 of a touch sensor element 120 and a parallel connection of the proximity sensor cells 132 of a proximity sensor element 130).

[0078] Even if in the Fig. While in Figures 3a to 5c, the touch sensor cells 122 and the proximity sensor cells 132 are depicted as circles and disks, respectively, these are not limited to this. It is also possible to integrate sensor cells with other shapes into the chip. According to one embodiment, the touch sensor cells 122 and / or the proximity sensor cells 132 are CMUT cells and / or PMUT cells.

[0079] The modular design allows the number, structure and / or arrangement of the touch sensor elements 120 and the proximity sensor elements 130 to be varied depending on the application. According to the Fig. 3a to 5c, the touch sensor element 120 has 39 touch sensor cells 122, and each proximity sensor element 130 has 14 proximity sensor cells 132. Furthermore, successive cell rows are arranged offset from one another, for example, in order to arrange the sensor cells within a sensor element in the most space-saving manner possible. Adjacent rows overlap, for example, at least partially, without adjacent touch sensor cells 122 and / or adjacent proximity sensor cells 132 overlapping.

[0080] In Fig. 3b shows a touch sensor element 120 and a proximity sensor element 130, according to an embodiment, in an enlarged view. Fig. 3b may be a section of the MEMS device 100 of Fig. 3a.

[0081] Fig. 4a and Fig. 4b shows a possible interconnection of sensor cells (122, 132) within a sensor element (120, 130). The sensor cells of a sensor element are each connected to a first terminal 160 and a second terminal 162. The first terminal 160 represents, for example, a reference terminal or ground terminal, and the second terminal 162 represents, for example, a signal terminal (e.g., "bias terminal") or a positive terminal. For example, a possible cell connection for a tactile and a spacer element via a positive and a ground terminal (e.g., "ground terminal") is shown. Other configurations are also possible. These configurations are an example where there is very low parasitic capacitance.

[0082] According to one embodiment, the first terminal 160 does not have the same functionality for all sensor elements. The same applies to the second terminal 162. The contact pads (the first terminal 160 and the second terminal 162) can be controlled or read differently for the individual elements (e.g., for the individual sensor cells 122, 132 and / or for the individual touch 120 and proximity sensor elements 130). Practically, each individual sensor element (in Fig. 3a shows, as an example, 4 touch sensor elements 1201-1204 and 4 proximity sensor elements 1301-1304) which can be individually controlled.

[0083] According to one embodiment, first electrodes (e.g., arranged on the wafer 112) of the sensor cells are connected to the first terminal 160 and second electrodes (e.g., the plate 142) of the sensor cells are connected to the second terminal 162.

[0084] According to one embodiment, an alternating voltage can be applied between the two terminals 160, 162 in order to excite a movable electrode (e.g., the first electrode or the second electrode) of the proximity sensor cells 132 to oscillate and thus enable an ultrasonic time-of-flight measurement.

[0085] Fig. 4a and Fig. 4b, for example, show sections of the MEMS device 100 Fig. 3a.

[0086] The Fig. 5a to 5c show additional different embodiments of the MEMS device 100 of Fig. 3a with a load transfer element 150 and / or a protective layer 152.

[0087] The load transfer elements 150 and the protective layers 152 are in the Fig. 5a to 5c are formed as cuboids. Using suitable deposition and structuring processes, these can also be formed into pyramids, hemispheres, or similar shapes.

[0088] Optionally, an additional protective layer can be added. This can be placed as a thin film covering the entire chip or just the proximity sensor.

[0089] This film can be structured. The advantage is that there is no mechanical interaction with the proximity sensor and protection against mechanical influences, dust, moisture, etc. can be provided.

[0090] In other words, Fig. 5a Touch sensor elements 120, which are covered, for example, with polymer (e.g., load transfer elements 150 or contact bumps), and proximity sensor elements 130, which are open (not covered). Optionally, the "further" protective layer can be placed as a type of thin film over the entire chip. The "further" protective layer rests, for example, on the load transfer elements 150 and is arranged freely above the proximity sensor elements 130. This prevents any mechanical interaction between the "further" protective layer and the proximity sensor element.

[0091] In other words, Fig. 5b Touch sensor elements 120, which are covered, for example, with polymer (e.g., load transfer elements or contact bumps), and proximity sensor elements 130, which are partially covered for protection. The protective layers 152, each arranged over two adjacent proximity sensor elements 130, have a smaller thickness than the load transfer elements arranged over two adjacent touch sensor elements 120.

[0092] In other words, Fig. 5c Touch sensor elements 120 and proximity sensor elements 130, which are, for example, completely covered with polymer.

[0093] In Fig. 6a and Fig. 6b shows a control circuit 170, ie a control configuration for transmitting, as an example for a capacitive micromechanical ultrasonic transducer (CMUT) as a proximity sensor cell 132 for a MEMS device, according to an embodiment.

[0094] According to one embodiment, the control circuit 170 in Fig. 6a comprises a signal controller 172, a signal source 174, a DC source 176 and a bias tee 178. The signal controller 172, in Fig. 6a, can be configured to control the signal source 174 and the DC source 176. The two generated voltages are superposed via the bias tee 178 and transmitted to the proximity sensor 132. This converts the electrical signal into ultrasonic waves.

[0095] In Fig. 6b shows an alternative control circuit 170. The control circuit 170, in Fig. 6b, for example, includes a signal controller 172, a signal source 174, and a DC source 176. The signal controller 172 can be configured to regulate the signal source 174 and the DC source 176. The two voltages are superposed via various electrical contacts directly on the proximity sensor 132. This converts the electrical signal into ultrasonic waves.

[0096] In the case of a piezoelectric micromechanical ultrasonic transducer (PMUT) as proximity sensor cell 132, the DC source 176 and the bias tee 178 are omitted in the case of the Fig. 6a and the DC source 176 is omitted in the case of the configuration shown in Fig. 6b. In other words, in the case of a piezoelectric micromechanical ultrasonic transducer (PMUT) as the proximity sensor cell 132, the control circuit 170 includes the signal controller 172 and the signal source 174. The electrical signal from the signal source 174 is routed directly to the proximity sensor 132.

[0097] In Fig. 7a and Fig. 7b shows a readout circuit 180, ie a control configuration for receiving, as an example for a capacitive micromechanical ultrasonic transducer (CMUT) as a proximity sensor cell 132 for a MEMS device, according to an embodiment.

[0098] According to one embodiment, the readout circuit 180 in Fig. 7a includes a signal processor 182, an amplifier 184, a DC source 186, and a bias tee 188. A high-frequency electrical signal from the proximity sensor 132 caused by an ultrasonic wave is amplified by the amplifier 184 and transmitted to the signal processor 182. The reception sensitivity is controlled by the amplifier 184 and the DC source 186.

[0099] In Fig. 7b, an alternative readout circuit 180 is shown. The readout circuit 180, in Fig. 7b, for example, includes a signal processor 182, an amplifier 184, and a DC source 186. A high-frequency electrical signal from the proximity sensor 132, caused by an ultrasonic wave, is amplified by an amplifier 184 and transmitted to the signal processor 182. The reception sensitivity is controlled by the amplifier 184 and the DC source 186.

[0100] In the case of a piezoelectric micromechanical ultrasonic transducer (PMUT) as proximity sensor cell 132, the DC source 186 and the bias tee 188 are omitted in the case of the Fig. 7a and the DC source 186 is omitted in the case of the configuration shown in Fig. 7b. In other words, in the case of a piezoelectric micromechanical ultrasonic transducer (PMUT) as the proximity sensor cell 132, the readout circuit 180 includes the signal processing 182 and the amplifier 184. The electrical signal of the proximity sensor 132 is passed directly to the amplifier 184.

[0101] Fig. 8 shows a block diagram of a system configuration of a MEMS device 100 having at least one touch sensor element 120 and at least one proximity sensor element 130. The main modules of the system are shown on the left side and a flow diagram of the system is shown on the right side.

[0102] According to one embodiment, at least one or each of the touch sensor elements 1201-120 n have a plurality of touch sensor cells and at least one or each of the proximity sensor elements 1301-130 m may have multiple proximity sensor cells. The index n is a natural number and indicates the number of independent proximity sensor elements 130. The index m is a natural number and indicates the number of independent touch sensor elements 130. The sensor elements 130 / 120 and / or sensor cells may have features and / or functionalities as described in connection with at least one of the Fig. 1 to 7b.

[0103] Via a control circuit 1701, ie a control electronics, of the proximity sensor elements 130, ie the proximity sensor system, electrical pulses 175 Ni “Tx Ni” (i=1...n) to the proximity sensor elements 130 i"Ni". These convert the electrical signals 175 into ultrasonic waves 190 Ni "pTx Ni," which then interact with the environment. The response 192 to the totality of the signals 190 "pTx Ni" is recorded by the sensor system. Ultrasonic signals 192 reach Nj “pRx Nj” (j=1...n) the sensor element 130 “Nj”, which converts the ultrasonic signals 192 into electrical signals 183 Nj "Rx Nj" and transfers it to a readout circuit 1801, ie to the control electronics. The j-th receiving element can also receive response signals 192 i induced by the i-th transmitting element 130 i (for i≠j) are received. Using appropriate signal processing, the signals are processed and visualized.

[0104] The control of the touch sensor 120 is analog. In the case of a passive touch element 120 i are generated by electrical pulses 175 Bi“Tx Bi” (i=1...n) Measurement states of the touch sensor element 120 i “Bi” is set and a physical transmission pulse 190 Bi “pTx Bi” is omitted. A physical receive pulse 192 Bi “pRx Bj” (j=1...n) describes mechanical forces acting on the sensor 120 j “Bj” effect.

[0105] In the case of an active touch sensor 120, this can also generate ultrasonic waves 190 Bi Send "pTx Bi" (analogous to proximity sensor 130). As an active touch sensor 120, touch sensor 120 can be operated in a proximity sensor mode.

[0106] Thus, the proximity sensor elements 130 and optionally the touch sensor elements 120 can be controlled with an electrical transmission pulse 175, whereupon the sensor elements 130 / 120 transmit a physical transmission pulse 190 (e.g., ultrasound, electrostatics, magnetism, optics) to the environment. Both the proximity sensor elements 130 and the touch sensor elements 120 can receive a physical reception pulse 192 (e.g., ultrasound, electrostatics, magnetism, optics) and convert it into an electrical reception pulse 183.

[0107] The individual sensor elements 130 "Ni" and 120 "Bi" can be electrically grouped, for example, to increase the signal-to-noise ratio. The touch sensor elements 120 are, for example, configured to be operated as a proximity sensor element in a proximity sensor mode and / or the proximity sensor elements 130 are configured to be operated as a touch sensor element in a touch sensor mode. As a result, both proximity sensor elements 130 and touch sensor elements 120 can be grouped into a large proximity sensor, with both the proximity sensor elements 130 and the touch sensor elements 120 being operated in the proximity sensor mode. Conversely, proximity sensor elements 130 and touch sensor elements 120 can also be grouped into a large touch sensor, with both the proximity sensor elements 130 and the touch sensor elements 120 being operated in the touch sensor mode.

[0108] The modules “signal processing”, i.e. data processing, and “visualization” can combine the information from both sensor domains “proximity sensing” and “touch sensing”.

[0109] The system 100 can transfer information to an external control loop in order to actively intervene in the interaction between the sensor system and the environment (e.g., changing the gripping distance in a robot gripper).

[0110] Although some aspects have been described in connection with a device, it should be understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step. Analogously, aspects described in connection with or as a method step also represent a description of a corresponding block, detail, or feature of a corresponding device. Some or all of the method steps can be carried out by (or using) a hardware apparatus, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, some or more of the key method steps can be carried out by such an apparatus.

[0111] Depending on specific implementation requirements, embodiments of the invention may be implemented in hardware or software. The implementation may be performed using a digital storage medium, such as a floppy disk, a DVD, a Blu-ray Disc, a CD, a ROM, a PROM, an EPROM, an EEPROM, or a FLASH memory, a hard disk, or other magnetic or optical storage device storing electronically readable control signals that can interact or cooperate with a programmable computer system to perform the respective method. Therefore, the digital storage medium may be computer-readable.

[0112] Some embodiments according to the invention thus comprise a data carrier having electronically readable control signals capable of interacting with a programmable computer system such that one of the methods described herein is carried out.

[0113] In general, embodiments of the present invention may be implemented as a computer program product having program code, wherein the program code is operable to perform one of the methods when the computer program product is run on a computer.

[0114] The program code can, for example, also be stored on a machine-readable medium.

[0115] Other embodiments include the computer program for performing one of the methods described herein, wherein the computer program is stored on a machine-readable carrier.

[0116] In other words, an embodiment of the method according to the invention is thus a computer program which has a program code for carrying out one of the methods described herein when the computer program runs on a computer.

[0117] A further embodiment of the method according to the invention is thus a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program for performing one of the methods described herein is recorded. The data carrier, the digital storage medium, or the computer-readable medium are typically physical and / or non-perishable or non-transitory.

[0118] A further embodiment of the method according to the invention is thus a data stream or a sequence of signals that represents the computer program for carrying out one of the methods described herein. The data stream or the sequence of signals can be configured, for example, to be transferred via a data communication connection, for example via the Internet.

[0119] A further embodiment comprises a processing device, for example a computer or a programmable logic device, which is configured or adapted to carry out one of the methods described herein.

[0120] A further embodiment comprises a computer on which the computer program for performing one of the methods described herein is installed.

[0121] A further embodiment according to the invention comprises a device or a system designed to transmit a computer program for performing at least one of the methods described herein to a recipient. The transmission can be electronic or optical, for example. The recipient can be, for example, a computer, a mobile device, a storage device, or a similar device. The device or system can, for example, comprise a file server for transmitting the computer program to the recipient.

[0122] In some embodiments, a programmable logic device (e.g., a field-programmable gate array, an FPGA) may be used to perform some or all of the functionality of the methods described herein. In some embodiments, a field-programmable gate array may interact with a microprocessor to perform any of the methods described herein. In general, in some embodiments, the methods are performed by any hardware device. This may be general-purpose hardware, such as a computer processor (CPU), or method-specific hardware, such as an ASIC.

[0123] The devices described herein may be implemented, for example, using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

[0124] The devices described herein, or any components of the devices described herein, may be implemented at least partially in hardware and / or in software (computer program).

[0125] The methods described herein may be implemented, for example, using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

[0126] The methods described herein, or any components of the methods described herein, may be implemented at least in part by hardware and / or by software.

[0127] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein.

Claims

[1] MEMS device (100), having the following features: at least one touch sensor element (120, 1201-1204) configured to detect a touch (124) piezoelectrically, capacitively, optically, or magnetically; and at least one proximity sensor element (130, 1301-1304) configured to detect an object (200) spaced from the proximity sensor element (130, 1301-1304) with sound (190, 191, 192); wherein the at least one touch sensor element (120, 1201-1204) and the at least one proximity sensor element (130, 1301-1304) are integrated on a semiconductor chip (110); wherein the at least one touch sensor element (120, 1201-1204) comprises a plate (142) defining a recess (140) in an insulator (114) and configured to be bent upon contact; and wherein the at least one touch sensor element (120, 1201-1204) is designed to detect a bending of the plate (142) caused by a touch piezoelectrically, capacitively, optically or magnetically, wherein the MEMS device (100) is configured to determine a force of contact based on an intensity of the bending. [2] The MEMS device (100) of claim 1, wherein the at least one touch sensor element (120, 1201-1204) comprises a plurality of touch sensor cells (122) arranged in a one-dimensional array or two-dimensional array, and wherein the at least one proximity sensor element (130, 1301-1304) comprises a plurality of proximity sensor cells (132) arranged in a one-dimensional array or two-dimensional array. [3] MEMS device (100) according to claim 2, wherein the touch sensor cells (122) of the at least one touch sensor element (120, 1201-1204) are electrically connected in parallel to be driven and read in parallel and / or the proximity sensor cells (132) of the at least one proximity sensor element (130, 1301-1304) are electrically connected in parallel to be driven and read in parallel. [4] MEMS device (100) according to claim 2 or 3, wherein the touch sensor cells (122) of the at least one touch sensor element (120, 1201-1204) and / or the proximity sensor cells (132) of the at least one proximity sensor element (130, 1301-1304) are round. [5] MEMS device (100) according to claim 4, wherein the touch sensor cells (122) of the at least one touch sensor element (120, 1201-1204) and / or the proximity sensor cells (132) of the at least one proximity sensor element (130, 1301-1304) are arranged in rows and wherein adjacent rows are arranged offset from one another such that the adjacent rows at least partially overlap without adjacent touch sensor cells (122) and / or adjacent proximity sensor cells (132) overlapping. [6] MEMS device (100) according to one of claims 1 to 5, comprising a plurality of touch sensor elements (120, 1201-1204) and proximity sensor elements (130, 1301-1304) arranged side by side in a plane. [7] MEMS device (100) according to one of claims 1 to 6, wherein the at least one proximity sensor element (130, 1301-1304) comprises at least one micromechanical ultrasonic transducer. [8] MEMS device (100) according to claim 7, wherein the micromechanical ultrasonic transducer is designed as a capacitive micromechanical ultrasonic transducer or as a piezoelectric micromechanical ultrasonic transducer. [9] MEMS device (100) according to claim 8, wherein the capacitive micromechanical ultrasonic transducer comprises a drive circuit (170) configured to excite a movable electrode (142) of the capacitive micromechanical ultrasonic transducer by means of an electrostatic force between the movable electrode (142) and a fixed electrode (112) of the capacitive micromechanical ultrasonic transducer to emit ultrasound (190); and wherein the capacitive micromechanical ultrasonic transducer has a readout circuit (180) designed to read out a change in distance between the movable electrode (142), which is deflected by means of an ultrasonic echo (192) reflected from the spaced-apart object (200), and the fixed electrode (112); wherein the piezoelectric micromechanical ultrasonic transducer comprises a control circuit (170) configured to control a deformation of a layer stack (142) comprising a piezoelectric layer of the piezoelectric micromechanical ultrasonic transducer, thereby emitting ultrasound (190); and wherein the piezoelectric micromechanical ultrasonic transducer comprises a readout circuit (180) configured to read out a deformation of the layer stack (142) based on an ultrasonic echo (192) reflected from the spaced-apart object (200). [10] MEMS device (100) according to one of claims 1 to 9, wherein the at least one touch sensor element (120, 1201-1204) comprises at least one micromechanical sensor structure. [11] MEMS device (100) according to claim 10, wherein the micromechanical sensor structure comprises a capacitive micromechanical sensor structure or a piezoelectric micromechanical sensor structure. [12] MEMS device (100) according to claim 11, wherein in the case of the capacitive micromechanical sensor structure, the plate (142) has a movable electrode and the capacitive micromechanical sensor structure has a readout circuit (180) which is designed to read out a change in distance between the movable electrode (142) of the capacitive micromechanical sensor structure and a fixed electrode (112) of the capacitive micromechanical sensor structure, wherein the movable electrode (142) is deflected by means of the touch (124) in order to cause the change in distance. wherein in the case of the piezoelectric micromechanical sensor structure, the plate (142) comprises a layer stack and the piezoelectric micromechanical sensor structure comprises a readout circuit (180) which is designed to read out a deformation of the layer stack (142), which comprises a piezoelectric layer, of the piezoelectric micromechanical sensor structure, based on the contact (124) of the layer stack. [13] MEMS device (100) according to one of claims 1 to 12, wherein a load transfer element (150) is arranged on the plate (142). [14] MEMS device (100) according to one of claims 1 to 13, wherein a protective layer (152) is arranged over the at least one proximity sensor element (130, 1301-1304). [15] MEMS device (100) according to claim 13 or 14, wherein one or the protective layer (152) is arranged above the at least one proximity sensor element (130, 1301-1304) and / or one or the load transmission element (150) is arranged on the plate (142), wherein the load transmission element (150) and / or the protective layer (152) are cubic, cuboid, pyramidal or hemispherical. [16] MEMS device (100) according to one of claims 13 to 15, wherein one or the protective layer (152) is arranged above the at least one proximity sensor element (130, 1301-1304) and / or one or the load transmission element (150) is arranged on the plate (142), wherein the load transmission element (150) and / or the protective layer (152) comprises polymer material, elastomer material or comparable material. [17] MEMS device (100) according to one of claims 13 to 16, wherein a or the protective layer (152) is arranged over the at least one proximity sensor element (130, 1301-1304) and a or the load transfer element (150) is arranged on the plate (142), wherein the protective layer (152) has a smaller thickness than the load transfer element (150). [18] MEMS device (100) according to one of claims 1 to 17, wherein the semiconductor chip (110) comprises a flexible substrate. [19] MEMS device (100) according to one of claims 1 to 18, wherein the at least one touch sensor element (120, 1201-1204) is configured to be operated in a proximity sensor mode as a proximity sensor element (130, 1301-1304).

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