Microscanner system, method and stack for the production thereof, and image projection device

Abstract

The invention relates to a microscanner system for projecting, in particular by way of imaging, electromagnetic radiation onto an observation field, the microscanner system comprising a substrate stack having a plurality of substrate layers stacked one on top of another along a stacking direction. A radiation source for generating the electromagnetic radiation, in particular one or more laser beams, is arranged in or on a first substrate layer of the substrate stack. A second substrate layer of the substrate stack comprises a microelectromechanical system, MEMS, having at least one deflection element which is arranged in a beam path of the electromagnetic radiation and which is suspended in a manner capable of rotational oscillation about at least one oscillation axis, for the direction-variable deflection of at least one electromagnetic beam emittable by the radiation source. The microscanner system is produced by singulation from a stack in the form of a substrate stack or layer arrangement, such that the fabrication steps preceding singulation can be carried out for a plurality of microscanner systems at the stack level, in particular at the wafer stack level. An image projection device contains a plurality of multi-beam microscanner systems.

Description

[0001] Microscanner system, method and stack for its manufacture, and image projection device

[0002] The present invention relates to a microscanner system, in particular a single-beam or multi-beam system, for projecting electromagnetic radiation onto an observation field, in particular for imaging. It further relates to methods for producing a plurality of such microscanner systems and to substrate stacks that occur as intermediate products in the respective process.

[0003] Microscanners, which in technical jargon are also referred to as "MEMS scanners", "MEMS mirrors" or "micromirrors" or in English especially as "micro-scanners" or "micro-scanning mirrors" or "MEMS mirrors", are micro-electro-mechanical systems (MEMS), more precisely micro-opto-electro-mechanical systems (MOEMS), from the class of micromirror actuators for the dynamic modulation of electromagnetic radiation, in particular visible light. Depending on the design, the modulating movement of an individual mirror can be translational or rotational about at least one axis. In the first case, a phase-shifting effect is achieved, in the second case a deflection of the incident electromagnetic radiation in a direction dependent on the current orientation of the mirror. In the following, microscanners are considered in which the modulating movement of an individual mirror is, at least partly, rotational.In contrast to mirror arrays, where the modulation of incident light occurs via the interaction of several mirrors on a single MEMS component, the modulation in microscanners is typically generated via a single mirror per MEMS component (microscanner).

[0004] Microscanners can therefore be used, in particular, to deflect electromagnetic radiation by modulating the deflection direction of an incident electromagnetic beam, in particular a laser beam, using a deflection element (“mirror”). This can be used, in particular, to create a Lissajous projection of the beam into an observation field. This allows, in particular, imaging and sensory tasks to be solved or display functionalities to be implemented. Furthermore, such microscanners can also be used to advantageously irradiate materials, in particular for their processing. Other possible applications include the illumination of certain open or closed spaces or spatial areas with electromagnetic radiation, for example, in the context of spotlight applications.Microscanners often consist of a mirror plate (deflection plate) suspended laterally on elastically stretchable springs. A distinction is made between single-axis mirrors, which are preferably mounted so they can rotate around a single axis, and dual-axis and multi-axis mirrors, which allow rotations, particularly rotational oscillations, around a corresponding number of different axes (oscillation axes), especially simultaneously.

[0005] A microscanner system for deflecting an electromagnetic beam can thus, in particular, comprise a biaxial microscanner, i.e., a microscanner with two different non-parallel, in particular mutually orthogonal, oscillation axes. However, it is also possible for the microscanner system to comprise a combination of two or more individual microscanners, in particular single-axis microscanners, which are arranged, in particular in series, such that the incident beam can be deflected successively by the various individual microscanners of the microscanner system in order to generate a two-dimensional deflection pattern, such as a raster scan or a Lissajous pattern. In a microscanner system with a combination of two or three single-axis microscanners, their non-parallel oscillation axes can, in particular, be orthogonal to one another in pairs.

[0006] In both the case of imaging sensors and a display function, a multi-axis microscanner system serves to deflect electromagnetic radiation such as a laser beam or a shaped beam from any other source of electromagnetic radiation at least two-dimensionally, e.g., horizontally and vertically, in order to scan or illuminate an object surface within an observation field. In particular, this can be done by the scanned laser beam sweeping a rectangular area on a projection surface in the observation field. Thus, microscanner systems with at least a two-axis microscanner or with several, in particular two, single- or multi-axis microscanners connected in series in the optical path are used in these applications.

[0007] A microscanner system can, in particular, comprise a plurality of single- or multi-axis microscanners, even if these are not connected in series in the aforementioned sense, but are each individually designed to deflect a dedicated beam. For example, a microscanner system can comprise a plurality of simultaneously operable, in particular multi-axis, microscanners, which can operate independently of one another or in a coordinated manner according to a defined scheme, each deflecting its own dedicated beam. Such a microscanner system is referred to herein as a "multi-beam microscanner system."

[0008] The wavelength range of the radiation to be deflected can, in principle, be selected from the entire spectrum, from short-wave UV radiation, through the VIS range, NIR range, IR range, FIR range, to long-wave terahertz and radar radiation. The or each radiation source for the electromagnetic radiation can, in particular, itself be an integral component of a micro-scanner system, particularly a multi-beam system, as is partly the case in the present solution.

[0009] For a range of different microscanner applications, particularly for applications in the field of so-called "wearables," i.e., electronics worn on the body, very compact and cost-effective laser projectors are required. One important design for this purpose features one or more microscanners for beam deflection and one or more laser sources. Wearables include, in particular, virtual reality (VR) glasses, augmented reality (AR) glasses, mixed reality (MR) glasses, and other body-worn imaging devices. The colors of the light generated by the light sources can, in the optical range of the spectrum, be primary colors of a color model for a color space and, for example, in the case of an RGB color model, be provided by three laser sources, one each for red, yellow, and blue light.

[0010] In some known designs of microscanner systems, the differently colored laser components of a multicolor laser source (with several correspondingly differently colored individual lasers) are separated by color and hermetically encapsulated in their own TO packages. Since these packages are usually large and expensive, only a limited degree of miniaturization can be achieved.

[0011] In the conventional manufacturing of microscanner systems, all components of the microscanner system are individually assembled to form the microscanner system. This applies even to components such as integrated semiconductor circuits, which have previously been mass-processed and manufactured in parallel on semiconductor substrates. They are first separated into chips and then precision-assembled at chip level on a common carrier component of the microscanner system. The components of the microscanner system, which may include one or more MEMS mirrors, heat sinks, submounts, optics, and laser chips, must therefore all be individually mounted, aligned, mounted, contacted, and secured during the manufacturing of the microscanner system.

[0012] It is an object of the invention, particularly with regard to their efficient manufacturability and / or miniaturization possibilities, to provide improved single-beam and multi-beam microscanner systems and methods for their respective manufacture.

[0013] This problem is solved according to the teaching of the independent claims. Various embodiments and further developments of the solution are the subject of the dependent claims.

[0014] A first aspect of the solution presented here relates to a microscanner system for projecting, in particular for imaging, electromagnetic radiation into an observation field, in particular into a solid angle emanating from the microscanner system. The microscanner system comprises a substrate stack with a plurality of substrate layers stacked one upon another along a stacking direction. Arranged in or on a first substrate layer of the substrate stack are a number N of radiation sources, in particular laser radiation sources, each with one or more lasers for generating the electromagnetic radiation, for example, one or more laser beams of different colors, where N > 1 applies. For the sake of simplicity of description, the cases N = 1 and N > 1 are treated separately in some places below:

[0015] - In the case N = 1, a second substrate layer of the substrate stack has a micro-electro-mechanical system (MEMS) with at least one deflection element arranged in a beam path of the electromagnetic radiation and suspended so as to be capable of rotational vibration about at least one oscillation axis for deflecting at least one electromagnetic beam emitted by the radiation source in a direction-variable manner.

[0016] - In the case where N > 1, the microscanner system is multi-beam and the substrate stack is monolithic. The N radiation sources are each configured to emit a respective electromagnetic beam (130-i) as the radiation component of the electromagnetic radiation (130). A second substrate layer (112) of the substrate stack has, for each radiation source (120), an associated MEMS with at least one deflection element (112a) arranged in the beam path of the electromagnetic beam (130i) of the respective radiation source and suspended so as to be capable of rotational oscillation about at least one oscillation axis, for deflecting the electromagnetic beam emitted by the respective radiation source (120) in a directionally variable manner.

[0017] The term "substrate layer," as used herein, refers to a homogeneous or heterogeneous material layer. In a temperature range intended for use with the microscanner system, the material layer is typically a solid. It can, in particular, have a plate-like shape, at least in sections, and, depending on its function, can be made, in particular, from a semiconductor wafer or a material that is at least partially optically transparent in the wavelength range used by the microscanner system for projection, such as a glass wafer or an at least partially transparent plastic wafer.

[0018] The term "radiation source," as used herein, refers to a source of electromagnetic radiation to be deflected, in particular scanned, by the microscanner system. It can, in particular, be a source of laser radiation. The wavelength range of the radiation can, in principle, be selected from the entire spectrum, from short-wave UV radiation, through the VIS range, NIR range, IR range, FIR range, to long-wave terahertz and radar radiation. The term "deflection element," as used here, refers, in particular, to a body having a reflective surface (mirror surface) smooth enough that reflected electromagnetic radiation, e.g., visible light, retains its parallelism according to the law of reflection, thus allowing an image to be formed. The roughness of the mirror surface must, for this purpose, be less than approximately half the wavelength of the electromagnetic radiation.Roughnesses with a mean roughness value Ra < 1000 nm, preferably Ra < 100 nm, and especially preferably Ra < 5 nm are particularly suitable. The mean roughness value indicates the average distance of a measuring point on the surface from the center line. The mean roughness value thus corresponds to the arithmetic mean of the absolute deviation from the center line and is defined in particular in the standard DIN EN ISO 4287:2010. The deflection element can in particular be designed as a mirror plate with at least one mirror surface or have such a surface. In particular, the mirror surface itself can consist of a different material than the rest of the body of the deflection element, e.g., of a metal, in particular a deposited metal.

[0019] The term "monolithic," as used here, with reference to a body (in particular a substrate stack), means that the body is formed in one piece, such that the various substrates or layers of the stack are firmly connected to one another, so that the substrate stack forms a single unit. Any components formed in the substrate stack, in particular the radiation source and MEMS, are formed integrally with the substrate stack or as part thereof, in particular such that the substrate stack completely defines these components. In particular, the MEMS assigned to the radiation sources can also be combined as an integrated monolithic MEMS, in which an assigned deflection element is formed for each radiation source.

[0020] The terms "comprises," "includes," "includes," "has," "has," "with," or any other variation thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or has a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or that are inherent in such a method or apparatus.

[0021] Furthermore, unless explicitly stated to the contrary, "or" refers to an inclusive "or" and not an exclusive "or." For example, a condition A or B is satisfied by one of the following conditions: A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), and both A and B are true (or present).

[0022] The terms "a" or "an" as used herein are defined as "one or more." The terms "another" and "another," and any other variations thereof, are defined as "at least one other."

[0023] The term “plurality” as used herein shall mean “two or more”.

[0024] The terms "first," "second," "third" and similar terms in the description and claims are used to distinguish between similar or otherwise identically named elements and not necessarily to describe a sequential, spatial, or chronological order. It is understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments of the solution described herein may also function in orders other than those described or illustrated. The term "configured" or "arranged" to perform a particular function (and respective variations thereof), as used herein, is to be understood that a related device or component thereof is already in a configuration or setting in which it can perform the function or at least can be set to perform it - i.e.Configurable - means that it can perform the function after being set accordingly. The configuration can be carried out, for example, by setting parameters of a process sequence or switches or similar devices to activate or deactivate functionalities or settings. In particular, the device can have several predetermined configurations or operating modes, so that configuration can be carried out by selecting one of these configurations or operating modes.

[0025] - In the case N = 1, a microscanner system according to the first aspect can be advantageously manufactured within the framework of parallel processing, particularly due to its stack-like structure, in which a substrate stack is constructed from substrates corresponding to the substrate layers of the microscanner systems, so that a plurality of microscanner systems are formed simultaneously and adjacently arranged by constructing a substrate stack and can be obtained from this by subsequent singulation. The microscanner systems can thus be manufactured, in particular, within the framework of parallel processing "at wafer level" (wafer-level processing), wherein the respective individual components of the microscanner systems, or at least a substantial portion thereof, are formed in the layer structure of the substrate stack, in particular as individual substrates or substrate layers thereof.This eliminates the need for individual housing of components prior to integration into the microscanner system, resulting in space savings and thus a particularly compact design and manufacturing efficiency (especially integration density). This also eliminates the need for individual housing of individual components of the microscanner system, such as laser sources.

[0026] - In the case N > 1, a multi-beam microscanner system according to the first aspect can be advantageously manufactured, particularly due to its stacked structure, within the framework of parallel processing, in which a layer arrangement is constructed from substrates corresponding to the substrate layers of the multi-beam microscanner system, so that a plurality of multi-beam microscanner systems are formed simultaneously and adjacently by the construction of the layer arrangement and can be obtained from this by subsequent singulation. The multi-beam microscanner systems can thus be manufactured, in particular, within the framework of parallel processing "at wafer level" (wafer-level processing), wherein all or at least a subset of the respective individual components of the multi-beam microscanner systems are formed in the layer structure of the layer arrangement.This eliminates the need for individual housing of components prior to integration into the multi-beam micro-scanner system, resulting in space savings and thus a particularly compact design and manufacturing efficiency (particularly integration density). This also eliminates the need for individual housing of individual components of the multi-beam micro-scanner system, such as laser sources. Since, in the case of N > 1, the multi-beam micro-scanner system can generate a plurality of electromagnetic beams, particularly simultaneously, and deflect them individually or collectively in a coordinated manner, this allows the realization of micro-projectors with particularly high radiation output and highly variable radiation patterns.

[0027] In the following, the term "layer arrangement" is used with regard to the case N > 1 for a layer stack of substrates in which a plurality of multi-beam microscanner systems are formed. A layer arrangement can be produced in particular by stacking substrates, each of which is made of wafers, in particular (at least predominantly) from a semiconductor material such as silicon. However, the term "layer arrangement" also encompasses arrangements that result from dividing, in particular cutting, such a layer stack and that, after dividing, comprise two or more of the microscanner systems. For example, rectangular pieces, each comprising a plurality of microscanner systems, can be cut from a wafer stack with a circular cross-section (perpendicular to the stacking direction).Such rectangular parts are particularly suitable as "tiles" for assembling image projection devices by arranging several such tiles in a grid. This allows even large-area image projection devices to be created efficiently.

[0028] The term "substrate stack" is used here, in contrast to the term "layer arrangement," specifically for the layer structure within a single microscanner system. Within the framework of the aforementioned parallel processing "at the wafer level," the layer arrangement can thus first be manufactured before a plurality of microscanner systems are obtained from it by singulation, e.g., using a sawing process. Their respective layer structures form their respective substrate stacks, which in turn are obtained from stacked substrates of the layer arrangement as a section of the layer arrangement obtained during singulation.

[0029] Below, various exemplary embodiments of the microscanner system are described, each of which, unless expressly excluded or technically impossible, can be combined with each other as well as with the other aspects of the present solution described below. Unless otherwise specified, the embodiments apply both to the case N = 1 and to the case N > 1.

[0030] In some embodiments:

[0031] - in the case of N = 1, the radiation source is configured to emit the electromagnetic radiation it generates at least predominantly as a focused beam with a beam direction deviating by an angle of no more than 10° from the stacking direction of the substrate stack. The beam direction can coincide, at least substantially, with the stacking direction, in particular deviate from it by no more than 1°. This allows for particularly compact designs, since the entire beam path within the respective microscanner systems runs through the stack structure. Thus, thanks to its design, in particular through the possible integration of optical elements, the stack structure can also be used for targeted beam guidance and beam shaping;

[0032] - in the case of N > 1, at least one of the radiation sources (120) or the multi-beam micro-scanner system (100) as a whole is configured to emit the electromagnetic radiation generated thereby at least predominantly as a bundled beam with a beam direction deviating from the stacking direction (101) of the substrate stack by an angle of at most 10°, in particular by no more than 1°. Furthermore, particularly in the case that the multi-beam micro-scanner system as a whole is configured to emit the electromagnetic radiation generated thereby at least predominantly as a bundled beam, particularly high radiation intensities and, in the case of differently colored radiation from two or more of the radiation sources, also a bundled beam with a correspondingly mixed color can be generated. In some embodiments, the substrate stack has at least one further substrate layer in or on which

[0033] - in the case N = 1, a beam-shaping optic, in particular a diffractive or refractive one, is designed for beam shaping, which is configured to shape, in particular to collimate, the at least one electromagnetic beam before and / or after its deflection by the deflection element.

[0034] - in the case of N > 1, for each radiation source, a beam-shaping optic, in particular a diffractive or refractive beam-shaping optic, is configured for beam-shaping, which is assigned to the radiation source individually or jointly with at least one other radiation source and is configured to shape, in particular to collimate, the electromagnetic beam (130-i) of the respective radiation source (120) before and / or after its deflection by the deflection element (112a) assigned to the respective radiation source.

[0035] The provision of one or more beam-shaping layers in the substrate stack makes it possible to implement any requirements regarding the beam profile of the electromagnetic radiation to be projected by the microscanner system into the observation field by the substrate stack itself, in particular by components belonging to it and thus to the microscanner system itself, so that external optics for this purpose are not necessary. This can also be used to reduce the overall space required and thus to miniaturize the projection solution as a whole. In addition, beam shaping can be carried out in close spatial proximity, i.e. at a short distance, from the respective radiation source, which can be used in particular to improve the optical properties of the microscanner system itself or of the radiation that can be projected by it into the observation field.According to one variant, in the case where N > 1, two or more of the radiation sources can share a common beam-shaping optics, meaning that the beams from these radiation sources pass through the same beam-shaping optics. This eliminates the need to provide individually assigned beam-shaping optics for each radiation source. In particular, these radiation sources can be selected such that their colors or wavelengths are different and span a color space, e.g., an RGB color space.

[0036] In some embodiments, the substrate stack comprises, as each such further substrate layer, at least one third substrate layer with - in the case N = 1: a first beam-shaping optics formed therein for beam shaping, wherein the first beam-shaping optics is configured to shape the at least one electromagnetic beam before its deflection by the deflection element; and

[0037] - in the case N > 1: each radiation source (120) has a first beam-shaping optical unit for beam shaping formed therein, which is assigned to it individually or jointly with at least one other radiation source, wherein the first beam-shaping optical units are each configured to shape the electromagnetic beam (130-i) of the respective assigned radiation source (120) before it is deflected by the deflection element (112a) assigned to the respective radiation source (120).

[0038] In some embodiments, the substrate stack comprises, as each such further substrate layer, in addition to or instead of the at least one third substrate layer, at least one fourth substrate layer with

[0039] - in the case N = 1: a second beam-shaping optical unit formed therein for beam shaping, wherein the second beam-shaping optical unit is configured to shape the at least one electromagnetic beam after its deflection by the deflection element; and

[0040] - in the case N > 1: each radiation source (120) has a second beam-shaping optical unit (116a, 118) formed therein for beam shaping, wherein the second beam-shaping optical units (116a, 118) are each configured to shape the at least one electromagnetic beam (130) of the respective associated radiation source after its deflection by the deflection element (112a) associated with the respective radiation source (120).

[0041] In both of the aforementioned embodiments (third layer / fourth substrate layer), and especially in the case of the combination of at least a third substrate layer with at least a fourth substrate layer, the beam shaping can, in particular, comprise collimating the (respective) beam. This allows the imaging properties, in particular the achievable image sharpness, of the microscanner system to be optimized.

[0042] In some embodiments, in the case N = 1, the beam-shaping optics or at least one of the beam-shaping optics comprises an axicon, a parabolic mirror and / or a planar deflection mirror for at least partially beam-shaping the electromagnetic beam; and

[0043] - in the case N > 1, at least one of the beam-shaping optics assigned to a respective radiation source (120) comprises an axicon, a parabolic mirror and / or a planar deflecting mirror for at least partially beam-shaping the electromagnetic beam emitted by the assigned radiation source (120).

[0044] If at least one axicon is used, the respective axicon can in particular be designed as a reflective axicon. In all of the above-mentioned cases, the respective beam-shaping optics can be arranged such that they direct the radiation generated by the respective radiation source or the beam emitted by it onto the deflection element by means of reflection on the beam-shaping optics, in particular onto a mirror surface of the deflection element, which is arranged on a side of the deflection element facing away from the radiation source (when the deflection element is in a non-deflected rest position). The deflection element can in particular have a central opening through which the beam emitted by the associated radiation source can at least partially reach the beam-shaping optics, where it can be reshaped and directed onto the mirror surface of the deflection element. The beam reshaping can in particular comprise generating an annular beam cross-section.The use of one or a combination of several of the aforementioned types of beam-shaping optics can thus be used, on the one hand, to generate a desired beam shape and / or, on the other hand, to achieve a particularly compact design, since the beam does not have to be guided laterally around the deflection element. However, it is also possible to provide a beam feedthrough in the substrate in which the deflection element is formed, at a location other than that of the deflection element, through which the beam from the associated radiation source can at least partially reach the radiation optics without first passing through or impinging on the deflection element.

[0045] One or more of the beam-shaping optics can also be designed as collimators. The collimators can, in particular, be configured such that they collimate only along a single spatial dimension running perpendicular to the beam direction, i.e., for example, they transform a circular beam cross-section into a linear, in particular rectilinear, beam cross-section. This can be used, in particular, to achieve a corresponding collimation for each oscillation axis of the deflection element. In another variant, the collimators can be configured such that they transform a divergent elliptical beam into a collinear beam with a circular beam cross-section.

[0046] In some embodiments, the substrate stack comprises at least a fifth substrate layer in or on which a driver circuit

[0047] - in the case N = 1: for electrically controlling the radiation source and / or a driver circuit for controlling a drive of a rotary oscillating movement of the deflection element about the at least one oscillation axis; and

[0048] - in case N > 1: for electrical control of one or more of the

[0049] Radiation sources (120) and / or at least one driver circuit (102a) for controlling one or more drives of the rotary

[0050] Oscillating movements of one or more of the deflection elements (112a) about their respective at least one oscillation axis.

[0051] The or every fifth substrate layer can in particular be a semiconductor substrate in or on which the driver circuit(s) is / are formed as an integrated circuit. The fifth substrate layer can in particular be interconnected with the first substrate layer and connected to it, directly or indirectly via an interconnection level as a further substrate layer, so that the spatial distance between the respective radiation source(s) and the respective driver circuit(s) for controlling it, and thus electrical resistance and / or electromagnetic interference (from outside or through induction or similar), can be kept very low. In the case of N > 1, in particular at least one driver circuit can be designed as a driver circuit serving for several, in particular all, radiation sources or drives, for example as an integrated circuit, or as a separate circuit for each radiation source orDrive can be divided, in particular by means of separate integrated circuits.

[0052] In some embodiments, the first substrate layer is arranged between the fifth substrate layer and the second substrate layer, viewed along the stacking direction. In particular, the emission direction for the electromagnetic radiation can be defined as pointing away from both the first and the fifth substrate layer, so that the fifth substrate layer, which is usually opaque (especially in the case of a semiconductor material), does not interfere with the beam path.

[0053] Especially in some variants of these designs

[0054] - in the case N = 1: (i) the fifth substrate layer comprises the driver circuit for controlling a drive for the oscillating movement of the deflecting element; (ii) the second substrate layer comprises at least one actuator for driving the oscillating movement of the deflecting element; and (iii) the first substrate layer comprises an electrical line running through it for the direct or indirect electrical connection of the actuator to the driver circuit for controlling the drive; and

[0055] - in the case N > 1: (i) the fifth substrate layer for each deflection element has the associated driver circuit for controlling a drive for the oscillating movement of the respective deflection element; (ii) the second substrate layer for each deflection element has at least one actuator for driving the oscillating movement of the respective deflection element; and (iii) the first substrate layer for each actuator has an electrical line running through it for the direct or indirect electrical connection of the actuator to the driver circuit for controlling the drive.

[0056] In both cases, the line can be designed as a so-called "via," such as a through-silicon via (TSV) in the case of one or more silicon layers in the substrate stack, or a through-glass via (TGV) in the case of one or more glass layers in the layer stack. These variants also promote a compact design, particularly in the lateral direction (i.e., in the layer plane), since the line runs through the first substrate layer.

[0057] In some embodiments, the substrate stack comprises at least a sixth substrate layer by means of which

[0058] - in case N = 1 : a first cavity formed in the substrate stack is hermetically sealed; and

[0059] - in the case N > 1: in the substrate stack, a first cavity (112b) is formed which is assigned to each deflection element and is hermetically sealed. In both cases, the deflection element or at least one of the deflection elements can be arranged in the hermetically sealed first cavity and can be suspended in a rotationally oscillating manner about the at least one oscillation axis. Thus, on the one hand, the respective deflection element is well protected against unwanted external influences, such as chemical or mechanical influences or interfering radiation, and on the other hand, this design also promotes a particularly compact design of the microscanner system. The cavity can, in particular, be evacuated and thus serve as a vacuum encapsulation in order to reduce or minimize air frictional resistance that would otherwise occur during the oscillation movement, depending on the quality of the vacuum, and in particular even to at least substantially avoid it entirely.

[0060] In some embodiments,

[0061] - in the case N = 1 : the radiation source is arranged at least partially within a second cavity formed in the first substrate layer; and

[0062] - in the case N > 1: at least one of the radiation sources is arranged at least partially within a second cavity formed in the first substrate layer for each radiation source individually or for several of the radiation sources together.

[0063] This allows the same or similar advantages to be achieved with regard to the respective radiation source as with the first cavity with regard to the deflection element.

[0064] Specifically, in some of these embodiments, a surface section of a side wall of the or at least one second cavity has at least one electrically conductive, in particular metallic, layer for establishing a respective electrical connection of the or at least one radiation source arranged at least partially in this respective second cavity. This also allows for a particularly space-efficient electrical connection of the radiation source.

[0065] The term "electrical conductivity" (and variations thereof), as used herein, refers to a physical quantity that indicates the ability of a substance to conduct electrical current. "Electrically conductive" or "electrically conducting" is understood here to mean an electrical conductivity that (at 25 °C) is at least 10 6 S / m.

[0066] In some embodiments - in the case N = 1: the first cavity or second cavity is evacuated or the first cavity and / or the second cavity contains a gas at a gas pressure below normal pressure, which consists at least predominantly of a protective gas; and

[0067] - in the case N > 1 : at least a first cavity or a second cavity is evacuated or contains a gas at a gas pressure below normal pressure, which consists at least predominantly of a protective gas.

[0068] The respective first and / or second cavity can thus be evacuated, ie a gas with a gas pressure of 10 Pa (10 -4bar) or less (every real vacuum is not completely free of matter). In the first cavity, this is particularly advantageous with regard to oscillation of the deflection element that is as free of gas friction and thus with low losses. In the second cavity, however, other advantages are more important, such as corrosion protection and protection against contamination of the radiation source. It is also possible for one of the two cavities to be evacuated (e.g., the first cavity), while the other cavity (e.g., the second cavity) is filled with a protective gas (particularly below normal pressure).

[0069] In some embodiments, the microscanner system further comprises: (i) a seventh layer and (ii) projection optics for imaging the intermediate image into the observation field.

[0070] - In the case N = 1: the seventh layer is arranged in the beam path of the radiation source and is designed as a diffusing screen or a ground glass screen such that when it is irradiated with the beam of the radiation source, an intermediate image is formed on the seventh layer; and

[0071] - in the case N > 1 : the seventh layer is arranged in the respective beam paths of at least two of the radiation sources and is designed as a diffusing screen or a focusing screen in such a way that when it is irradiated with the rays of these at least two radiation sources, an intermediate image is formed on the seventh layer.

[0072] The seventh layer can, in particular, be arranged downstream of the respective deflection element(s) along the path of the beam path(s), so that the intermediate image at the seventh layer is generated by the beam striking the deflection element or by the beams previously deflected at the associated deflection element striking it. The projection optics, which can, in particular, comprise a projection lens, are then arranged such that they project the intermediate image created at the seventh layer in transmission or reflection into the observation field (i) directly or (ii) indirectly through one or more further layers of the substrate stack.

[0073] In some embodiments,

[0074] - In case N = 1: the radiation source for at least partially generating the electromagnetic radiation comprises one or more of the following radiation emitters: edge-emitting laser, surface-emitting laser (Vertical Cavity Surface Emitting Laser, VCSEL), superluminescent diode (SLED), mini-LED, micro-LED; and in case N > 1: at least one of the radiation sources for at least partially generating its respective electromagnetic beam comprises one or more of the following radiation emitters: edge-emitting laser, surface-emitting laser, superluminescent diode, mini-LED, micro-LED.

[0075] These radiation emitters can be applied or introduced onto the first substrate layer, e.g., a silicon substrate or another mechanically suitable carrier substrate, in particular by a suitable transfer process.

[0076] In some embodiments,

[0077] - In the case N = 1: the deflection element has a rotational symmetry with respect to an axis of symmetry running parallel to the stacking direction and the radiation source is designed such that the electromagnetic beam generated by it during its operation runs along the axis of symmetry of the deflection element and through an opening therein; and

[0078] - in the case where N > 1: at least one deflection element has rotational symmetry with respect to an axis of symmetry running parallel to the stacking direction, and the radiation source associated with the respective deflection element is configured such that the electromagnetic beam generated during operation runs along the axis of symmetry of the associated deflection element and through an opening therein. Such a configuration can also be used to realize particularly compact designs, since beam deflection around the respective deflection element(s) can be omitted. Furthermore, highly symmetrical designs can also be realized overall.

[0079] In some embodiments,

[0080] - in the case N = 1: the microscanner system is designed such that, during operation of the radiation source, the electromagnetic beam (130) generated by it passes the deflection element through an opening in the second substrate layer to a reflective surface, where the beam is deflected onto the deflection element to be reflected there; and

[0081] - in the case N > 1 : the microscanner system is designed such that for at least one radiation source, during its operation, the electromagnetic beam generated by it passes the deflection element assigned to it through an opening in the second substrate layer to a reflective surface where the beam is deflected onto this deflection element to be reflected there.

[0082] This can bring various advantages, in particular it leads to an angle of incidence different from 90° for the respective beam falling from the reflective surface onto the deflection element in the rest position of the deflection element, thus counteracting in particular the occurrence of undesired ghost images and / or scattered light effects. In some embodiments, one or more of the substrate layers, for example the first substrate layer and / or the second substrate layer, each have at least one alignment mark, by means of which at least two of the substrate layers of the microscanner system are aligned with one another in a dimension running transversely to the stacking direction. In this way, the precision of the relative alignment of the various substrate layers can be increased, in particular with regard to achieving high-precision alignments in which optical disturbances caused by incorrect alignments (e.g.aberrations) are at least reduced to negligible sizes.

[0083] In some embodiments, one or more of the substrate layers, such as the first substrate layer and / or the second substrate layer, each have at least one alignment accuracy feature, based on which the accuracy of the relative alignment of at least two of the substrate layers of the microscanner system with respect to at least one spatial dimension (in particular orthogonally and / or along the stacking direction) can be determined. With the aid of the at least one alignment accuracy feature, the quality of the microscanner system or precursors thereof can be evaluated, in particular before the substrate stack or layer arrangement is separated into individual microscanner systems. This can also be used, in particular, to select out stacks or (after separation) microscanner systems that do not meet a predetermined quality criterion as evidenced by this evaluation.This increases manufacturing efficiency because the rejected substrate stacks or microscanner systems do not need to be processed further. It also ensures that products with misalignments are not delivered to market undetected. As a quality criterion (e.g. permissible tolerance range), a tolerance of a maximum of 5 pm, preferably a maximum of 1 pm, or even better a maximum of just 0.3 pm has proven to be a useful quality criterion, particularly for lateral precision (i.e. across, in particular orthogonal to, the stacking direction). In tests, a spacing accuracy of a maximum of 100 pm, preferably a maximum of 10 pm, and particularly preferably a maximum of 1 pm, for the spacing between successive substrate layers in the substrate stack (or the corresponding substrates in the layer arrangement before singulation) has proven to be a useful quality criterion in the dimension along the stacking direction.

[0084] In some embodiments, the microscanner system further comprises one or more cooling elements, each extending into or through at least two of the substrate layers and made of a material that has increased thermal conductivity compared to its respective immediate surroundings in the substrate stack. The cooling elements can, in particular, comprise metallic material fillings, depending on the type of substrate layers used, in so-called through-silicon vias (TSV) or through-glass vias (TGV) as heat sinks. This allows heat, in particular heat generated by the radiation source during its operation, to be effectively dissipated in the microscanner system along the heat transport paths defined by the cooling elements, without the need for cooling elements external to the stack.

[0085] In some embodiments for the case N > 1, at least one of the radiation sources is configured to emit its respective electromagnetic beam in a wavelength range that differs at least proportionally from, and in particular does not overlap with, a wavelength range of the beam of at least one radiation source. This allows for the realization of a multi-beam microscanner system that can display different colors time-dependently and / or as a mixed color depending on the control of the radiation sources.

[0086] In particular, for the case N > 1, the microscanner system can have at least two monochromatic radiation sources whose emission wavelengths are selected differently, so that together they span an at least two-dimensional color space extending across different colors. The individual colors of the color space can then be specifically selected, for example, by appropriately controlling the individual radiation sources and / or MEMS of the microscanner system. Such a multi-beam microscanner system thus forms a microprojector that can display different colors in its projection area, in particular with temporal and / or spatial variability. The multi-beam microscanner system can thus be designed, for example, as an RGB module for at least partially displaying a color space based on the RGB color model.

[0087] In some embodiments for the case N > 1, the radiation sources are designed such that the beam directions of their respective bundled beams run parallel and adjacent to one another in such a way that the bundled beams of the radiation sources are perceivable in the observation field as adjacent, differently colored subpixels of a pixel formed by the subpixels as a whole. Thus, in analogy to an LCD or LED display, multi-color capable pixels can be generated during projection, in which the pixel color perceivable by a viewer is achieved through the interaction of neighboring subpixels of different wavelengths or colors. The individual monochrome subpixels, in particular the radiation sources and any associated optics, can thus be designed or become optimized with regard to the respective wavelength, while the entire pixel is multi-color capable due to the different wavelengths of its subpixels.It is nevertheless also conceivable that the subpixels share elements or are identical to one another and are designed for a broadband rather than just monochrome wavelength range, which could also facilitate manufacturing. For example, this could apply to anti-reflection coatings ("AR coatings") or so-called highly reflective coatings ("HR coatings"), for which a subpixel-specific design would be rather challenging from a manufacturing perspective. A subpixel-specific design, optimized for a monochrome wavelength, could, however, be used particularly for diffractive (grating-like) structures for beam shaping, since these can generally be produced side by side without any problems – even in parallel processing – and only need to be adapted to the respective subpixel wavelength with regard to the "grating constants."

[0088] In some embodiments for the case N > 1, all radiation sources are configured to emit their respective electromagnetic beam, in particular (with respect to the integral of the radiation intensity l(A) over the wavelength A) predominantly or even exclusively, in a wavelength range that is the same for all radiation sources and has a width of a maximum of 100 nm, in particular a maximum of 50 nm, or monochromely at a wavelength that is the same for all radiation sources. This allows for the realization of projectors fed by all radiation sources and thus with high radiation output for the specific, narrow wavelength range. In particular, in the case of the aforementioned focused beam, a high radiation intensity can be achieved.In particular, the wavelength range can lie within a spectral range of a single primary color, i.e., within a spectral range that is located within the spectrum and limited in such a way that all individual colors in this spectral range belong to the same primary color, such as blue, green, yellow, or red. For example, all radiation sources can emit their respective radiation in a single, common, narrowly defined wavelength range (e.g., green: e.g., 515 nm ... 525 nm, blue: e.g., 415 nm ... 435 nm, or red: e.g., 625 nm ... 700 nm).

[0089] A second aspect of the present solution relates to a stack comprising a plurality of substrates stacked on top of one another along a stacking direction, which substrates are fastened to one another at the respective interfaces of adjacent substrates by means of a respective bonding connection, such as a wafer bonding connection, an anode bonding connection, or a eutectic bonding connection, depending on the material of the substrates.

[0090] - in case N = 1: the stack is a substrate stack in which a plurality of, in particular mutually similar, microscanner systems according to the first aspect (for case N = 1) are arranged adjacent to one another in such a way that the microscanner systems can each be obtained from the substrate stack by separation, in particular sawing or laser cutting. In each of the microscanner systems, its respective substrate stack contains

[0091] Substrate layers form an associated section of the substrate stack or are formed therefrom, wherein the substrates of the substrate stack each form one of the substrate layers; and - in the case N > 1: the stack is a layer arrangement in which a plurality of multi-beam microscanner systems according to the first aspect (for the case N > 1) are formed adjacent to one another in such a way that the multi-beam microscanner systems can each be obtained from the layer arrangement by singulation, in particular sawing or laser cutting, individually or in at least two groups of two or more mutually adjacent microscanner systems. Each of the multi-beam microscanner systems contains a respective section of the layer arrangement, so that the regions of the substrates of the layer arrangement contained in the respective section and stacked one above the other each form one of the substrate layers of the microscanner system formed in the respective section.

[0092] The term "substrate," as used herein, refers to a homogeneous or heterogeneous material layer, as with the previously introduced term "substrate layer." In a temperature range intended for use with the microscanner system, the material layer is typically present as a solid. In particular, it may have a plate-like shape, at least in sections. The term "substrate" is used herein to refer to a material layer that is simultaneously a proportional component of a majority of the microscanner systems (in particular, all microscanner systems) in the substrate stack (case n = 1) or layer arrangement (case n > 1). In contrast, the term "substrate layer" is used to refer to a material layer that, after being separated from the substrate stack or layer arrangement, is only part of one of the microscanner systems.The singulation can be carried out, in particular, using known singulation methods for singulating chips from semiconductor substrates, such as sawing or laser cutting. In particular, the singulation can be carried out by separating the substrate stack or layer arrangement along cutting lines that run transversely, in particular orthogonally, to the stacking direction.

[0093] The term “substrate” can refer in particular to a wafer, such as a wafer made of semiconductor material or a material that is at least partially transparent in a wavelength range used by the microscanner system for projection, such as a glass material or plastic. The shape of a main surface of the substrate, in particular wafer, can in particular be circular or rectangular, although other shapes are not excluded. In particular, the substrate stack (case n = 1) or the layer arrangement (case n > 1) can contain one or more semiconductor substrates as well as one or more glass substrates (the same applies to the substrate stack of the multi-beam microscanner systems with regard to its substrate layers). Furthermore, it is possible that, in addition to or instead of one or more glass substrates, a plastic substrate that is at least partially transparent in the relevant wavelength range is included in the substrate stack or layer arrangement.of the layer arrangement. Such plastic substrates can in particular be designed as plastic optical wafers, i.e., contain one or more imaging optics. Such plastic substrates are generally more cost-effective to manufacture than glass substrates. They can advantageously be arranged in the substrate stack or in the layer arrangement, particularly where, within the scope of the manufacturing process for the substrate stack or the layer arrangement, no hermeticity requirements are met and no subsequent high-temperature steps are required. Then, one or more plastic substrates with additional optical functions, such as a "relay optic" or "beam widening optic," can be cost-effectively connected downstream of the MEMS or MEMS in the respective beam path. Such downstream optics can be particularly useful if a specific augmented reality waveguide (e.g.in the case of spectacle applications, a spectacle lens) requires a certain magnification of the beam cross-section in order to suppress parasitic artifacts that would otherwise occur.

[0094] A third aspect of the present solution relates to an image projection device for projecting an image into a projection field, wherein the image projection device comprises a plurality of multi-beam microscanner systems according to the first aspect of the present solution for the case N > 1, each configured to display one pixel of the image to be projected. The projection field thus results from the superposition of the individual observation fields of the individual microscanner systems, whereby these observation fields can be overlapping or separate from one another. A combination of these two alternatives is also conceivable, in particular to achieve an image display in which both color-variable and monochrome image areas occur.In some embodiments, the image projection device has one or more layer arrangements according to the second aspect, wherein each of the layer arrangements contains a respective number of at least two of the microscanner systems of the image projection device. In this way, even large image projection devices, in particular with a wide variety of projection field contours, can be manufactured particularly efficiently. This can be achieved in particular by assembling the image projection device in a tiled manner (see above) by arranging a plurality of layer arrangements (and optionally further individual microscanner systems) in a grid-like manner, each of which serves as "tiles". A fourth aspect of the present solution relates to a method for producing a plurality of microscanner systems according to the first aspect, wherein the method comprises:

[0095] - in the case N = 1: (i) stacking a plurality of substrates along a stacking direction to produce a stack formed as a substrate stack according to the second aspect, wherein adjacent substrates in the substrate stack are fastened to one another at their interface, in particular by means of a respective bond connection; and (ii) separating at least two of the microscanner systems from the substrate stack to obtain individual microscanner systems; and

[0096] - in the case N > 1: (i) stacking a plurality of substrates along a stacking direction to produce a stack formed as a layer arrangement according to the second aspect, wherein adjacent substrates in the layer arrangement are fastened to one another at their intermediate interface, in particular by means of a respective bond connection; and (ii) isolating at least two of the microscanner systems individually or into at least two groups each comprising two or more adjacent microscanner systems from the layer arrangement to obtain individual microscanner systems or units corresponding to the groups, each comprising a plurality of microscanner systems.

[0097] In particular, in order to achieve a particularly high manufacturing efficiency, 100 or more, in particular even 1,000, 10,000 or more microscanner systems can be separated from the substrate stack or the layer arrangement, for which purpose the latter then contains at least this number of microscanner systems.

[0098] The substrate stack or the layer arrangement according to the second aspect can thus be regarded in particular as an intermediate product in the parallelized production of a plurality of microscanner systems according to the first aspect.

[0099] The term "stacking" of substrates refers here to any form of creating a substrate stack (in the case of N = 1) or a layer arrangement (in the case of N > 1) of successive material layers along the stacking direction, with each material layer being referred to as a "substrate." This can therefore particularly involve stacking solid-state substrates, such as wafers. Depending on the material, layer deposition, for example, by liquid deposition followed by drying or curing, sputtering, or gas deposition processes (such as chemical vapor deposition, CVD), or mixed forms, are also conceivable.

[0100] In some embodiments of the method, stacking the substrates on top of one another comprises forming at least two partial substrate stacks (in the case where N = 1) or partial layer arrangements (in the case where N > 1) by stacking two or more of the substrates on top of one another in each partial substrate stack or partial layer arrangement. Adjacent substrates in each partial substrate stack or partial layer arrangement are thereby fastened to one another at their intermediate interface, in particular by means of a respective bond connection (in particular by wafer bonding). The partial substrate stacks or partial layer arrangements and optionally further substrates are then stacked on top of one another and fastened to one another at the interfaces, in particular again by means of a respective bond connection, in order to form the substrate stack or the layer arrangement as a whole.In particular, it is possible to align the substrates and / or partial stacks to be joined very precisely to achieve an optimal fit. In this case, fit accuracies in the sub-micrometer range are particularly advantageous and achievable. Furthermore, it is also possible to fabricate housings for the microscanner systems on a stack-by-stack basis, i.e., before singulation. This can be achieved, in particular, in the form of so-called wafer-level packaging (WLP), similar to pure semiconductor wafers.

[0101] One or more of the optionally present further substrates can be arranged in particular between the partial substrate stacks or partial layer arrangements, so that the stacking of the partial substrate stacks or partial layer arrangements can take place not only directly, but instead also indirectly, namely including one or more further substrates lying between the partial substrate stacks or partial layer arrangements.

[0102] The formation of partial substrate stacks or partial layer arrangements can be used advantageously in particular to implement process parallelization, in which two or more partial substrate stacks or partial layer arrangements are produced simultaneously, thus enabling an increase in throughput. For example, different stacking stations can be used simultaneously in a production line to produce the various partial substrate stacks or partial layer arrangements before these and, if applicable, the other substrates are assembled to form the entire substrate stack or partial layer arrangement. This also makes it easy to implement manufacturing differences, such as different individual processes or process controls for the individual partial substrate stacks or partial layer arrangements, without having to resort to other partial substrate stacks orPartial layer arrangements or their production must be taken into account, for example with regard to usable processes or temperature or pressure ranges.

[0103] In some embodiments,

[0104] - in the case N = 1: an alignment mark is produced in or on at least one selected substrate layer, and at least one other substrate layer is adjusted with respect to its relative position to the selected substrate layer(s) by means of the respective alignment mark during formation of the substrate stack; and

[0105] - in the case N > 1: in or on a first substrate of the layer arrangement, for each of the multi-beam micro-scanner systems formed in the layer arrangement, the radiation sources assigned to it, each having one or more radiation emitters, are formed in situ or individually or combined, mounted as a prefabricated component; and during the production of the substrate stack, the first substrate thus equipped with the radiation sources of the multi-beam micro-scanner systems is adjusted as a whole relative to a second substrate.

[0106] - In particular, all substrate layers or substrates can be aligned using such alignment markings on one or more of the other substrate layers or substrates. This allows for highly precise alignment of the substrate layers or substrates with each other and thus, in particular, high optical quality of the microscanner systems.

[0107] In some embodiments, before separating:

[0108] - in the case N = 1 : in or on the first substrate layer of the substrate stack, for each of the microscanner systems formed in the substrate stack, the radiation source assigned to it, which has one or more

[0109] Radiation emitters, formed in situ or assembled as a prefabricated component, in particular simultaneously (and thus highly efficiently) for all microscanner systems of the substrate stack. During the production of the substrate stack, the first substrate layer thus equipped with the radiation sources of the microscanner systems is then aligned as a whole relative to the second substrate layer, in particular using the alignment markings of the individual substrate layers involved in the alignment; and

[0110] - in the case N > 1: in or on a first substrate of the layer arrangement, for each of the multi-beam micro-scanner systems formed in the layer arrangement, the radiation sources assigned to it, each having one or more radiation emitters, are formed in situ or mounted individually or combined as a prefabricated component; and during the production of the substrate stack, the first substrate thus equipped with the radiation sources of the multi-beam micro-scanner systems is then adjusted as a whole relative to a second substrate.

[0111] For this purpose, the adjustment may, in particular, comprise (i) activating the respective radiation sources of at least two microscanner systems that are not directly adjacent in the substrate stack or in the layer arrangement, preferably located far apart from each other, and (ii) aligning the first substrate layer or the first substrate with at least one other of the substrate layers (or vice versa) or the first substrate (or vice versa) based on a radiation pattern generated overall by the activated radiation sources. The further the activated radiation sources are from each other, the higher the achievable adjustment accuracy is generally.

[0112] In some embodiments, the method further comprises: (i) measuring a thickness of the produced stack prior to singulation; (ii) comparing the measured thickness with a tolerance criterion defined for this purpose; (iii) if the measured thickness exceeds a value classified as tolerable by the tolerance criterion, selecting the stack and omitting singulation; and (iv) otherwise performing singulation. In this way, the quality of the microscanner system or precursors thereof can also be evaluated and used to increase the efficiency of the manufacturing process and for quality assurance.

[0113] The features and advantages explained with regard to the first aspect of the solution also apply accordingly to the other aspects of the solution. Further advantages, features, and possible applications of the present solution emerge from the following detailed description in conjunction with the figures.

[0114] It shows:

[0115] Fig. 1 schematically shows a cross-sectional view through a microscanner system according to an exemplary embodiment for the case N = 1;

[0116] Fig. 2 schematically shows an exemplary embodiment of a substrate stack with a plurality of microscanner systems, e.g. according to Fig. 1;

[0117] Fig. 3 is a flow chart illustrating an exemplary embodiment of a method for manufacturing a plurality of microscanner systems, e.g., according to Fig. 1;

[0118] Fig. 4A and 4B schematically show, according to two exemplary embodiments, a cross-sectional view through a single MEMS projector within a microscanner system for the case N > 1 and a multi-beam microscanner system composed thereof;

[0119] Fig. 5 schematically shows an exemplary embodiment of a layer arrangement with a plurality of multi-beam microscanner systems, e.g. according to Fig. 4A or Fig. 4B;

[0120] Fig. 6 is a flowchart illustrating an exemplary embodiment of a method for manufacturing a plurality of microscanner systems, e.g., according to Fig. 4A or Fig. 4B;

[0121] Fig. 7 is a schematic representation of an image projection device with a projection unit based on a plurality of multi-beam micro-scanner systems in the case N > 1;

[0122] Fig. 8 is a plan view of a first embodiment of the projection unit from Fig. 7, in which different-colored MEMS projectors are provided for each microscanner system; and Fig. 9 is a plan view of a second embodiment of the projection unit from Fig. 7, in which each microscanner system has only MEMS projectors of the same color.

[0123] In the figures, like reference numerals designate like, similar, or corresponding elements. Elements shown in the figures are not necessarily drawn to scale. Rather, the various elements shown in the figures are depicted in such a way that their function and general purpose will be understood by those skilled in the art. Connections and couplings between functional units and elements shown in the figures can also be implemented as indirect connections or couplings, unless expressly stated otherwise.

[0124] Fig. 1 shows a microscanner system 100 for the case N = 1 e according to an exemplary embodiment in a cross-sectional view along a section line AA shown in Fig. 2 through a substrate stack 200.

[0125] The microscanner system 100 comprises a substrate stack consisting of a plurality of substrate layers 102 to 118 stacked one upon another along a stacking direction 101, each of which has an at least approximately or partially plate-like shape. Adjacent substrate layers are mechanically connected to one another. Depending on the material of the respective substrate layers to be connected, this can be achieved, in particular, by means of a known wafer bonding process, such as direct bonding, anodic bonding, eutectic bonding, glass frit bonding, or adhesive bonding.

[0126] The base substrate of the substrate stack is a plate-shaped semiconductor substrate layer 102, in particular a semiconductor chip with at least one circuit integrated therein. In the present example, the semiconductor substrate layer 102 contains, on the one hand, a first driver circuit 102a for a drive device with at least one actuator (e.g., a piezo actuator) for driving an oscillatory movement of a deflection element 112a of the microscanner system 100, and a second driver circuit 102b, which is configured as a driver circuit for a laser device 120 of the microscanner system 100 serving as a radiation source.

[0127] The laser device 120 can have one or more lasers, in particular laser diodes, as radiation emitters 120a. In the case of multiple radiation emitters, these can differ, in particular with regard to the wavelengths of the laser radiation 130 they can emit. For example, three lasers can be provided that represent the primary colors of a color model of a color space, such as the primary colors red (R), green (G), and blue (B) of the RGB color model, so that a wide variety of colors from the color space can be represented by superimposing their laser radiation. The lasers can, in particular, be integrated into a common component that represents the laser device 120. In particular, such a laser device 120 can also be designed to combine beams (e.g., superimpose the individual R, G, B beams at a point). For this purpose, the laser device 120 can, in particular, have optical guides 120b.The radiation emitters 120a and the optical conductors 120b (waveguides) can, in particular, also be integrated together (and optionally with additional components such as filters, e.g., tunable filters) in a photonic integrated circuit (PIC). The following types of radiation emitters are particularly suitable: edge-emitting lasers, surface-emitting lasers, superluminescent diodes, mini-LEDs, and micro-LEDs. The radiation emitters 120a of the laser device 120 can be selected to be the same or different in terms of their type. It is also conceivable that the aforementioned beam combining does not occur in the laser device 120, but only in a subsequent region of the beam paths of the individual beams from the various radiation emitters.The substrate stack can accordingly be configured such that the beam paths of the various radiation emitters initially run separately before being combined in the region of one or more layers downstream of the laser device 120. For this purpose, a correspondingly configured optically active substrate layer can be provided.

[0128] In the substrate stack, substrate layer 102 is followed by a further substrate layer 104, wherein between the two layers there is a connection layer with electrical contacts 124a to 124c for electrically connecting terminals of driver circuits 102a and 102b to electrical lines 126 and 122, respectively, for connection to the drive device for deflection element 112a and to laser device 120, respectively. Laser device 120 is at least partially housed in a cavity 104a of substrate layer 104. Substrate layer 104 thus corresponds to the aforementioned "first" substrate layer.

[0129] The connection layer can be continuous, for example as a continuous wiring layer, or present in places, in particular in the form of only the electrical contacts 124a to 124c, which can be formed in particular by soldered connections or via eutectic bond connections. In particular, one or more of these connections can be specifically designed to act both as a mechanical connection (possibly with hermetic sealing) and as an electrical connection. In addition to the electrical contacts 124a to 124c, an electrically insulating material, in particular an underfill (so-called "underfill"; not shown), can also be present in order to strengthen the mechanical connection between the substrate layers 102 and 104, for example within the framework of a material-to-material connection (adhesive connection).The underfilling can in particular also be designed to at least partially compensate for differences in thermal expansion coefficients between the two substrate layers 102 and 104 in order to increase the temperature resistance of the substrate stack and thus the reliability of the microscanner system 100.

[0130] In addition, one or more cooling elements 136 can be arranged in one or more substrate layers of the substrate stack, in particular in substrate layer 104, for cooling purposes. They can be configured, in particular, as channels filled with a highly thermally conductive material, in particular a metal, e.g., of the TSV or TGV type, so that they can act as a heat sink relative to their surroundings. Their path can, in particular, be aligned parallel to the stacking direction 101. In addition, they can be thermally connected to another, stronger heat sink, such as a heat sink (not shown), in order to better dissipate the heat they absorb.

[0131] In the further construction of the substrate stack, the substrate layer 104 is followed by a further substrate layer 106, which is formed from a material that is at least partially transparent in the wavelength range of the laser source 120 (in the case of multiple lasers, in their total used wavelength range), in particular from glass or a transparent plastic. The substrate layer 106 is configured to collimate electromagnetic radiation emitted by the laser source 120 by means of beam-shaping optics (e.g., by means of fast-axis collimation, FAC) or to focus it, in each case in particular in a radiation plane spanned by the stacking direction and a direction orthogonal thereto, in which a (first) oscillation axis of the deflection element 112a runs.In a microscanner system having two oscillation axes for the deflection element, the first oscillation axis can, in particular, be selected such that its associated natural and / or resonant frequency is greater than that of the other oscillation axis. The substrate layer 106 can, in particular, also be designed such that it forms the above-mentioned optically effective substrate layer for beam combination. After a further substrate layer 108, which serves as a spacer and has a central opening through which the beam path of the radiation 130 collimated by the substrate layer 106 passes, a further substrate layer 110 follows in the stack structure. Similar to the substrate layer 106, it is formed from a material that is at least partially transparent in the wavelength range of the laser source 120, in particular from glass or a transparent plastic. It serves to (further) collimate the radiation 130 by means of beam-shaping optics (e.g.by means of slow-axis collimation (SAC) or to focus, in each case in a further radiation plane spanned by the stacking direction and a direction orthogonal thereto, in which further radiation plane a second oscillation axis of the deflection element 112a runs, which is orthogonal to the first oscillation axis. By combining the two substrate layers 106 and 110, the radiation can be collimated across its entire cross-section, so that after passing through the substrate layer 110 it can be described as a parallel beam of rays. The substrate layers 106 and 110 thus each correspond to an above-mentioned “third” substrate layer. Optionally, however, a stack structure is also possible in which the substrate layers 108 and 110 are omitted.

[0132] This is followed in the stack structure by a further substrate layer 112, in which a cavity 112b is formed centrally, in which the deflection element 112a is located. It is shown in Fig. 1 in three different positions, wherein the middle position, represented by black bars, also corresponds to a rest position of the deflection element 112a. The deflection element 112a has a ring shape, in particular that of a circular ring, so that it has a central opening 112d through which the radiation 130 coming from the substrate layer 110 can pass, as illustrated in Fig. 1. The substrate layer 112 thus corresponds here to the aforementioned "second" substrate layer. The deflection element 112a can in particular have a rotational symmetry, such as a circular symmetry or an n-fold rotational symmetry, with respect to an axis of symmetry 112c running parallel to the stacking direction 101.

[0133] In order to be able to generate a projection, in particular a multi-dimensional one, the deflection element 112a is attached to a frame-shaped section of the substrate layer 112 surrounding it via a suspension with one or more springs in such a way that it can simultaneously perform a rotational oscillation about each of the oscillation axes. The suspension can in particular be configured such that each of the rotational oscillations is harmonic in an angular range up to a maximum deflection angle when it occurs as a free oscillation, i.e. that the restoring force of the springs with respect to the respective oscillation axis obeys Hooke's law, at least to a good approximation. It is also conceivable that the suspension is configured such that the deflection element 112a and its suspension form a Duffing oscillator.

[0134] To drive the oscillations, a drive device (not shown) is provided on the deflection element 112a. It can, in particular, comprise one or more piezo actuators, which are mounted, for example, on one or more of the springs in order to deform them by applying force when appropriately controlled by the driver circuit 102a. This deformation can cause the deflection element 112a to deflect from its rest position in order to initiate and / or continuously continue a one- or multi-dimensional oscillation of the deflection element 112a. In the aforementioned case where the substrate layers 108 and 110 are omitted, the substrate layer 112 can follow the substrate layer 106 directly in the stack structure.

[0135] The drive device is electrically connected to the driver circuit 102a via connecting lines routed through the underlying part of the substrate stack, of which only one connecting line 126 is shown as an example in Fig. 1. Electrically conductive, in particular metallic, connecting bond connections 128 are provided at the interfaces between adjacent substrate layers of the part of the substrate stack through which the connecting lines run in order to ensure good electrical conductivity along the or each line 126 as a whole.

[0136] For the connection bonds 128, metal-eutectic bonds, such as gold-tin bonds, or direct metal bonding processes, such as gold-gold bonds, are particularly suitable. For the vertical electrical line sections of the line(s) 126 in the substrate stack, electrically conductive vias are introduced into the respective substrate layers, for example, a so-called through-glass via (TGV) in the case of a glass substrate layer or a so-called through-silicon via (TSV) in the case of a silicon substrate layer. In addition to electrical conduction, the electrical lines 126, including the respective associated connection bonds 128, can also be used for thermal dissipation, which is particularly important for the substrate layer 104 with the typically heat-generating laser device 120.

[0137] The substrate layer 112 is followed by a further substrate layer 114, which, together with substrate layers 110 and 112, hermetically seals the cavity 112b with the deflection element 112a on all sides. Accordingly, the cavity 112b can be evacuated or at least filled with a gas under negative pressure, so that gas friction losses during the oscillation of the deflection element 112a can be (almost) completely avoided or at least significantly reduced. One or more, in particular all, additional cavities that may be present in the substrate stack can also be hermetically sealed and evacuated or under negative pressure. This can apply in particular to a cavity between the two collimator substrate layers 106 and 110 and / or to the cavity 104a in the substrate layer 104 in which the laser device 120 is located.

[0138] In the stacked structure, the substrate layer 114 is followed by another beam-shaping substrate layer 116, in which a transmitting axicon 116a is formed with a central reflection surface 116b applied thereon, acting as an additional reflective axicon. However, it is also conceivable for the substrate layers 114 and 116 to coincide, i.e., to form a single substrate layer structured to form the axicon.

[0139] In both cases, as shown in Fig. 1, a further substrate layer 118 can be located above this, which acts as a cover layer and simultaneously as a transmitting axicon or as a converging lens. The axicon 116a with the reflection surface 116b is arranged such that the radiation 130 emerging from the layer 114 during operation of the microscanner system 100 passes through the axicon 116a onto the reflection surface 116b, from where it is reflected onto the side of the deflection element 112a facing away from the laser device 120, on which side a mirror surface of the deflection element 112a is located. At this mirror surface of the deflection element 112a, the radiation is reflected again in order to be projected into the observation field through the substrate layer 114, the axicon 116a, a cavity between the substrate layers 116 and 118 and finally through the substrate layer 118 as a beam bundled by the latter.

[0140] The substrate layers 114, 116, and 118 are therefore each formed, at least in the region of the beam path of the radiation 130, from a material that is at least partially transparent in the wavelength range of the laser source 120 (with the exception of the reflection surfaces 116a and 116b). The material can be glass or a transparent plastic, and the materials of the various substrate layers 114 to 118 mentioned can also be different from one another. The substrate layers 116 and 118 each correspond to an aforementioned "fourth" substrate layer. Instead of the axicon, other beam-shaping optics are also conceivable, such as a parabolic mirror or a planar deflection mirror.

[0141] The substrate layer 114 can also be designed in particular as a ground glass or diffusing screen, so that when irradiated with the rays deflected by the deflection element, an intermediate image is formed thereon, which is then projected into the observation field by the substrate layers 116 and 118, which act as projection optics.

[0142] The stack structure of the microscanner system 100 may further comprise rewirings (not shown) for electrical connections, wherein the rewirings may be formed in particular as rewiring levels at or near the interfaces between adjacent substrate layers, in particular in or on the substrate layers 102, 104 and / or 112.

[0143] In particular, several, in particular even all, substrate layers of the microscanner system can have a rotational symmetry with respect to the symmetry axis 112c, such as a circular symmetry or, in the case of a square floor plan, a fourfold rotational symmetry.

[0144] The further reference symbols WS1 to WS3 and 200 will be discussed later with reference to Figs. 2 and 3.

[0145] Fig. 2 schematically illustrates an exemplary embodiment of a substrate stack 200, in particular wafer stacks, with a plurality of microscanner systems, e.g., microscanner systems 100 according to Fig. 1. The microscanner systems are arranged laterally adjacent to one another, similar to semiconductor chips on a semiconductor wafer. The stacked substrates of the substrate stack 200 each proportionally form the substrate layers of each of the substrate layers 102 to 118 formed in the substrate stack. The cross-section of the microscanner system 100 shown in Fig. 1 can be obtained, for example, along the dashed line AA.

[0146] Fig. 3 shows a flow chart to illustrate an exemplary embodiment 300 of a method for producing a plurality of microscanner systems for the case N = 1, e.g., microscanner systems 100 according to Fig. 1, to which reference is also made below. In the method 300, a substrate stack 200 according to Fig. 2 is first produced in processes 305 to 320. In each of the processes 305 to 315, only a part of the substrate stack 200 is produced as a respective partial substrate stack WS1, WS2, or WS3 thereof as a precursor product. These partial substrate stacks WS1, WS2, or WS3 are illustrated together with the substrate stack 200, each proportionally for a single microscanner system 100 in Fig. 1. Each of the processes 305 to 320 can, for example, be carried out in a dedicated production station or production line. In particular, the processes 315 and one or both of the processes 305 and 310 can be carried out in a temporally overlapping manner, ieat least partially simultaneously. However, it is also conceivable to execute the processes sequentially, in particular using a single production line. The order of processes 310 and 315 can be freely selected.

[0147] Specifically, in process 305, the partial substrate stack WS1 is created by bonding substrates corresponding to the substrate layers 106 to 110 together. This can be done, in particular, in an evacuated or negatively pressurized chamber, so that later, in each of the resulting microscanner systems 100, a respective cavity hermetically enclosed by substrate layers 106 to 110 is evacuated or under negative pressure. If the substrates are not yet supplied in a finished state, the process 305 can also include the production of these substrates. The partial substrate stack WS1 forms a collimator or focusing optics for the radiation 130 for each microscanner system 100 to be formed in the substrate stack 200, as explained in detail above with reference to Fig. 1.

[0148] In process 310, the partial substrate stack WS1 is supplemented to form the partial substrate stack WS2 by the substrates corresponding to the substrate layers 112 with the deflection element 112a and the substrate layer 114. If or to the extent that these substrates are not yet supplied in a finished state, the process 310 may also include the production of these substrates.

[0149] In process 315, the partial substrate stack WS3 is produced, wherein in particular the layer 104, which has already been structured as a precursor, is populated with the radiation source 120. In addition, substrates corresponding to the substrate layers 102 and 104, including the connection layer 124, are connected to one another. If or to the extent that these substrates are not yet supplied ready-made as precursors, the process 315 can also comprise the production of these substrates (as precursors). The radiation source is contacted by means of the connection layer 124. In process 320, to form the entire substrate stack 200, the previously produced partial stacks WS2 and WS3 are put together and supplemented by substrates corresponding to the substrate layers 116 and 118. To connect the respectively adjacent substrates and subsequently also the partial substrate stacks WS1, WS2 andWS3 and the substrate stack 200 as a whole, in particular the various wafer bonding methods already discussed above can be used, depending on the type of substrates to be joined. For the relative alignment of the substrate layers to be joined of the respective sub-stacks WS1 to WS3 to one another, as well as subsequently of the sub-stacks WS2 and WS3 to one another, before or during the respective joining, alignment markings 132 can be provided on one or more of the substrate layers. In addition, to increase the accuracy of the alignment and / or for the later evaluation of the produced substrate stack or the microscanner system 100 separated therefrom, one or more alignment accuracy features 134, for example in scale form, can be formed or have been formed previously on relevant substrate layers, e.g., as illustrated on substrate layer 104.

[0150] Instead or additionally, the alignment may comprise activating at least two microscanner systems that are not directly adjacent in the substrate stack, wherein the first substrate layer and thus the radiation sources 120 are aligned with respect to at least one, in particular all, of the other substrate layers based on a radiation pattern generated overall by the activated radiation sources. This is an advantageous method for achieving particularly high alignment precision, particularly in connection with the mutual alignment of partial stacks WS1 to WS3.

[0151] Once the substrate stack is completed, it can be tested as a whole in a test process 325. For this purpose, its thickness, in particular its maximum thickness, is measured and compared with a previously defined tolerance criterion, such as a permissible tolerance range for the thickness. If the tolerance criterion is not met (330 - no), the substrate stack as a whole is rejected as defective (350).

[0152] Otherwise (330 - yes), the method continues with a test process 335, in which the microscanner systems 100 formed in the substrate stack are individually, but preferably simultaneously, tested at the level of the substrate stack (i.e., in the case of wafers, at the wafer level). If defects are detected in certain microscanner systems 100, these can be marked as faulty and / or classified as defective in associated data structures.

[0153] Then, in a singulation process 340, the finished substrate stack 200 is singulated into the individual, already tested, microscanner systems 100 contained therein. This can be done, in particular, using a sawing process. Such sawing processes, e.g., using diamond-coated saws, can in particular correspond to those known from semiconductor technology for singulating semiconductor wafers into individual chips.

[0154] Microscanner systems previously marked or classified as defective can then be individually selected, in particular rejected, in a subsequent selection process 345.

[0155] Figures 4A and 4B show, for the case N > 1, according to an exemplary embodiment, in their lower part a microscanner system 100 comprising - for example, three - individual MEMS projectors, and in the upper part of the figure a single one of these MEMS projectors 100a as a cross-sectional view according to a section along a section line AA through a section of a layer arrangement 200 shown in Fig. 5 assigned to the MEMS projector 100a.

[0156] The MEMS projector 100a (partially) comprises a substrate stack composed of a plurality of substrate layers 102 to 118 stacked one upon another along a stacking direction 101, each of which has an at least approximately or partially plate-like shape. Adjacent substrate layers are mechanically connected to one another, which, depending on the material of the respective substrate layers to be connected, can be achieved in particular by means of a known wafer bonding process, such as direct bonding, anodic bonding, eutectic bonding, glass frit bonding, or adhesive bonding.

[0157] The base substrate of the substrate stack is a plate-shaped semiconductor substrate layer 102, in particular a semiconductor chip with a circuit integrated therein (in particular one for each MEMS projector). In the present example, the semiconductor substrate layer 102 contains, on the one hand, a first driver circuit 102a for a drive device with at least one actuator (e.g., a piezo actuator) for driving an oscillatory movement of a deflection element 112a of the MEMS projector 100a, and a second driver circuit 102b, which is configured as a driver circuit for a laser device 120 serving as a radiation source of the MEMS projector 100a.

[0158] The laser device 120 can have one laser (Fig. 4A) or multiple lasers (Fig. 4B), in particular laser diodes, as radiation emitters 120a. In the case of multiple radiation emitters, these can differ, in particular with regard to the wavelengths of the laser radiation 130 they can emit, or they can be the same. For example, three lasers can be provided that represent the primary colors of a color model of a color space, such as the primary colors red (R), green (G), and blue (B) of the RGB color model, so that by superimposing their laser radiation, a wide variety of colors from the color space can be represented by the laser device 120 itself and thus by a single MEMS projector. The lasers can, in particular, be integrated in a common component that represents the laser device 120. In particular, such a laser device 120 can also be designed such that it combines beams (e.g.Superposition of the individual R, G, B beams at one point). For this purpose, the laser device 120 can, in particular, have optical guides 120b. The radiation emitters 120a and the optical guides 120b (waveguides) can, in particular, also be integrated together (and optionally with additional components such as filters, e.g., tunable filters) in a photonic integrated circuit (PIC). The following types of radiation emitters are particularly suitable: edge-emitting laser, surface-emitting laser, superluminescent diode, mini-LED, micro-LED. The radiation emitters 120a of the laser device 120 can be selected to be the same or different in terms of their type. It is also conceivable that the aforementioned beam combining does not already occur in the laser device 120, but only in a subsequent region of the beam paths of the individual beams from the various radiation sources.The substrate stack can accordingly be designed such that the beam paths of the various radiation sources initially run separately before they are combined in the region of one or more layers following the laser device 120, for which purpose in particular a correspondingly configured optically active substrate layer can be provided.

[0159] In the substrate stack, substrate layer 102 is followed by a further substrate layer 104, wherein between the two layers there is a connection layer with electrical contacts 124a to 124c for electrically connecting terminals of driver circuits 102a and 102b to electrical lines 126 and 122, respectively, for connection to the drive device for deflection element 112a and to laser device 120, respectively. Laser device 120 is at least partially housed in a cavity 104a of substrate layer 104. Substrate layer 104 thus corresponds to the aforementioned "first" substrate layer.

[0160] The connection layer can be continuous, for example as a continuous wiring layer, or present in places, in particular in the form of only the electrical contacts 124a to 124c, which can be formed in particular by soldered connections or via eutectic bond connections. In particular, one or more of these connections can be specifically designed to act both as a mechanical connection (possibly with hermetic sealing) and as an electrical connection. In addition to the electrical contacts 124a to 124c, an electrically insulating material, in particular an underfill (so-called "underfill"; not shown), can also be present in order to strengthen the mechanical connection between the substrate layers 102 and 104, for example within the framework of a material-to-material connection (adhesive connection).The underfilling can in particular also be designed to at least partially compensate for differences in thermal expansion coefficients between the two substrate layers 102 and 104 in order to increase the temperature resistance of the substrate stack and thus the reliability of the microscanner system 100.

[0161] In addition, one or more cooling elements 136 can be arranged in one or more substrate layers of the substrate stack, in particular in substrate layer 104, for cooling purposes. They can be configured, in particular, as channels filled with a highly thermally conductive material, in particular a metal, e.g., of the TSV or TGV type, so that they can act as a heat sink relative to their surroundings. Their path can, in particular, be aligned parallel to the stacking direction 101. In addition, they can be thermally connected to another, stronger heat sink, such as a heat sink (not shown), in order to better dissipate the heat they absorb.

[0162] In the further construction of the substrate stack, the substrate layer 104 is followed by a further substrate layer 106, which is formed from a material that is at least partially transparent in the wavelength range of the laser source 120 (in the case of multiple lasers, in their total used wavelength range), in particular from glass or a transparent plastic. The substrate layer 106 is configured to collimate electromagnetic radiation emitted by the laser source 120 by means of beam-shaping optics (e.g., by means of fast-axis collimation, FAC) or to focus it, in each case in particular in a radiation plane spanned by the stacking direction and a direction orthogonal thereto, in which a (first) oscillation axis of the deflection element 112a runs.In a microscanner system having two oscillation axes for the deflection element, the first oscillation axis can, in particular, be selected such that its associated natural and / or resonant frequency is higher than that of the other oscillation axis. The substrate layer 106 can, in particular, also be configured to form the aforementioned optically effective substrate layer for beam combining.

[0163] After a further substrate layer 108, which serves as a spacer and has a central opening through which the beam path of the radiation 130 collimated by the substrate layer 106 passes, a further substrate layer 110 follows in the stack structure. Similar to the substrate layer 106, it is formed from a material that is at least partially transparent in the wavelength range of the laser source 120, in particular from glass or a transparent plastic. It serves to (further) collimate the radiation 130 by means of beam-shaping optics (e.g., by means of slow-axis collimation, SAC) or to focus it, in each case in a further radiation plane spanned by the stack direction and a direction orthogonal thereto, in which a second oscillation axis of the deflection element 112a runs, which oscillates orthogonally to the first oscillation axis.By combining the two substrate layers 106 and 110, the radiation can be collimated across its entire cross-section, so that after passing through the substrate layer 110, it can be described as a parallel beam. The substrate layers 106 and 110 thus each correspond to an aforementioned "third" substrate layer. Optionally, however, a stacked structure is also possible in which the substrate layers 108 and 110 are omitted.

[0164] This is followed in the stack structure by a further substrate layer 112, in which a cavity 112b is formed centrally, in which the deflection element 112a is located. It is shown in three different positions in Fig. 4A and Fig. 4B, wherein the middle position, represented by black bars, also corresponds to a rest position of the deflection element 112a. The deflection element 112a has an annular shape, in particular that of a circular ring, so that it has a central opening 112d through which the radiation 130 coming from the substrate layer 110 can pass, as illustrated in Fig. 4A and Fig. 4B, respectively. The substrate layer 112 thus corresponds here to the aforementioned "second" substrate layer. The deflection element 112a can, in particular, have a rotational symmetry, such as a circular symmetry or an n-fold rotational symmetry, with respect to an axis of symmetry 112c running parallel to the stacking direction 101.In order to be able to generate a projection, in particular a multi-dimensional one, the deflection element 112a is attached to a frame-shaped section of the substrate layer 112 surrounding it via a suspension with one or more springs in such a way that it can simultaneously perform a rotational oscillation about each of the oscillation axes. The suspension can in particular be configured such that each of the rotational oscillations is harmonic in an angular range up to a maximum deflection angle when it occurs as a free oscillation, i.e. that the restoring force of the springs with respect to the respective oscillation axis obeys Hooke's law, at least to a good approximation. It is also conceivable that the suspension is configured such that the deflection element 112a and its suspension form a Duffing oscillator.

[0165] To drive the oscillations, a drive device (not shown) is provided on the deflection element 112a. It can, in particular, have one or more piezo actuators, which are mounted, for example, on one or more of the springs in order to deform them by means of the application of force when appropriately controlled by the driver circuit 102a. This deformation can cause a deflection of the deflection element 112a from its rest position in order to initiate and / or continuously continue a one- or multi-dimensional oscillation of the deflection element 112a. In the aforementioned case that the substrate layers 108 and 110 are omitted, the substrate layer 112 can directly follow the substrate layer 106 in the stack structure. The substrate layer 112, together with the drive device, forms a MEMS, which in turn forms a component of the MEMS projector as a whole.

[0166] The drive device is electrically connected to the driver circuit 102a via connecting lines routed through the underlying part of the substrate stack, of which only one connecting line 126 is shown by way of example in Fig. 4A and Fig. 4B. Electrically conductive, in particular metallic, connecting bond connections 128 are provided at the interfaces between adjacent substrate layers of the part of the substrate stack through which the connecting lines run in order to ensure good electrical conductivity along the or each line 126 as a whole.

[0167] For the connection bonds 128, metal-eutectic bonds, such as gold-tin bonds, or direct metal bonding processes, such as gold-gold bonds, are particularly suitable. For the vertical electrical line sections of the line(s) 126 in the substrate stack, electrically conductive vias are introduced into the respective substrate layers, for example, a so-called through-glass via (TGV) in the case of a glass substrate layer or a so-called through-silicon via (TSV) in the case of a silicon substrate layer. In addition to electrical conduction, the electrical lines 126, including the respective associated connection bonds 128, can also be used for thermal dissipation, which is particularly important for the substrate layer 104 with the typically heat-generating laser device 120.

[0168] The substrate layer 112 is followed by a further substrate layer 114, which, together with substrate layers 110 and 112, hermetically seals the cavity 112b with the deflection element 112a on all sides. Accordingly, the cavity 112b can be evacuated or at least filled with a gas under negative pressure, so that gas friction losses during the oscillation of the deflection element 112a can be (almost) completely avoided or at least significantly reduced. One or more, in particular all, additional cavities that may be present in the substrate stack can also be hermetically sealed and evacuated or under negative pressure. This can apply in particular to a cavity between the two collimator substrate layers 106 and 110 and / or to the cavity 104a in the substrate layer 104 in which the laser device 120 is located.

[0169] In the stacked structure, the substrate layer 114 is followed by another beam-shaping substrate layer 116, in which a transmitting axicon 116a is formed with a central reflection surface 116b applied thereon, acting as an additional reflective axicon. However, it is also conceivable for the substrate layers 114 and 116 to coincide, i.e., to form a single substrate layer structured to form the axicon.

[0170] In both cases, as shown in Fig. 4A and Fig. 4B, a further substrate layer 118 can be located above this, which acts as a cover layer and simultaneously as a transmitting axicon or as a converging lens. The axicon 116a with the reflective surface 116b is arranged such that the radiation 130 emerging from the layer 114 during operation of the microscanner system 100 passes through the axicon 116a onto the reflective surface 116b, from where it is reflected onto the side of the deflection element 112a facing away from the laser device 120, on which side a mirror surface of the deflection element 112a is located. At this mirror surface of the deflection element 112a, the radiation is reflected again in order to be projected into the observation field through the substrate layer 114, the axicon 116a, a cavity between the substrate layers 116 and 118 and finally through the substrate layer 118 as a beam bundled by the latter.

[0171] The substrate layers 114, 116, and 118 are therefore each formed, at least in the region of the beam path of the radiation 130, from a material that is at least partially transparent in the wavelength range of the laser source 120 (with the exception of the reflection surfaces 116a and 116b). The material can be glass or a transparent plastic, and the materials of the various substrate layers 114 to 118 mentioned can also be different from one another. The substrate layers 116 and 118 each correspond to an aforementioned "fourth" substrate layer.

[0172] Instead of the axicon, other beam shaping optics are also conceivable, such as a parabolic mirror or a planar deflection mirror.

[0173] The substrate layer 114 can also be designed in particular as a ground glass or diffusing screen, so that when irradiated with the rays deflected by the deflection element, an intermediate image is formed thereon, which is then projected into the observation field by the substrate layers 116 and 118, which act as projection optics.

[0174] The stack structure of the MEMS projector 100a may further comprise rewirings (not shown) for electrical connections, wherein the rewirings may be formed in particular as rewiring levels at or near the interfaces between adjacent substrate layers, in particular in or on the substrate layers 102, 104 and / or 112.

[0175] In particular, several, in particular even all, substrate layers of the MEMS projector 100a can have a rotational symmetry with respect to the symmetry axis 112c, such as a circular symmetry or, in the case of a square floor plan, a fourfold rotational symmetry.

[0176] The further reference numerals 201 to 203 and 200 will be discussed later with reference to Figs. 5 and 6.

[0177] Fig. 5 schematically illustrates an exemplary embodiment of a layer arrangement 200, in particular a wafer stack, with a plurality of multi-beam microscanner systems, e.g., microscanner systems 100 according to Fig. 4A or Fig. 4B. The microscanner systems are arranged laterally next to one another, similar to semiconductor chips on a semiconductor wafer. The stacked substrates of the layer arrangement 200 form, in each case proportionally, the substrate layers of each of the microscanner systems 100 formed in the layer arrangement and thus also of their MEMS projectors 100a. The cross-sections of the respective microscanner system 100, each shown proportionally for only one MEMS projector in Fig. 4A and Fig. 4b, can be obtained, for example, along the dashed line AA.

[0178] Fig. 6 shows a flowchart illustrating an exemplary embodiment 300 of a method for manufacturing a plurality of microscanner systems, e.g., microscanner systems 100 according to Fig. 4A or Fig. 4B.

[0179] In the method 300, a layer arrangement 200 according to Fig. 2 is first produced in processes 305 to 320. In each of the processes 305 to 315, only a part of the layer arrangement 200 is produced as a respective partial layer arrangement 201, 202 or 203 thereof as a precursor. These partial layer arrangements 201, 202 or 203, like the layer arrangement 200, are each illustrated proportionally for a single MEMS projector 100a in Fig. 4A or Fig. 4B. Each of the processes 305 to 320 can, for example, be carried out in a production station or production line provided specifically for this purpose. In particular, the processes 315 and one or both of the processes 305 and 310 can be carried out in a temporally overlapping manner, i.e. at least partially simultaneously. However, it is also conceivable to execute the processes sequentially, particularly using a single production line. The order of processes 310 and 315 can be freely selected.

[0180] Specifically, in process 305, the partial layer arrangement 201 is created by bonding substrates corresponding to the substrate layers 106 to 110 together. This can be done, in particular, in an evacuated or negatively pressurized chamber, so that later, in each of the resulting microscanner systems 100, a respective cavity hermetically enclosed by substrate layers 106 to 110 for each MEMS projector 100a is evacuated or under negative pressure. If the substrates are not already supplied ready-made, the process 305 can also include the production of these substrates. The partial layer arrangement 201 forms a collimator or focusing optics for the radiation 130 for each MEMS projector 100a to be formed in the layer arrangement 200, as explained in detail above with reference to Figs. 4A and 4B.In process 310, the partial layer arrangement 201 is supplemented with the substrates corresponding to the substrate layers 112 with the deflection element 112a and the substrate layer 114 to form the partial layer arrangement 202. If or to the extent that these substrates are not already supplied ready-made, the process 310 may also include the production of these substrates.

[0181] In process 315, the partial layer arrangement 203 is created, wherein, in particular, the layer 104, which has already been structured as a precursor, is populated with the radiation source 120. In addition, substrates corresponding to the substrate layers 102 and 104, including the connection layer 124, are connected to one another. If or to the extent that these substrates are not already supplied as precursors, the process 315 can also include the production of these substrates (as precursors). The radiation source is contacted via the connection layer 124.

[0182] In process 320, to form the entire layer arrangement 200, the previously produced partial stacks 202 and 203 are assembled and supplemented by substrates corresponding to the substrate layers 116 and 118. Depending on the type of substrates to be connected, the various wafer bonding methods already discussed above can be used to connect the adjacent substrates and subsequently also the partial layer arrangements 201, 202, and 203, as well as the layer arrangement 200 as a whole. Alignment markings 132 can be provided on one or more of the substrates for the relative alignment of the substrate layers to be connected of the respective partial stacks 201 to 203 to one another, and subsequently of the partial layer arrangements 202 and 203 to one another, before or during the respective connection.In addition, to increase the accuracy of the alignment and / or for later evaluation of the layer arrangement produced or the microscanner systems 100 isolated therefrom, one or more alignment accuracy features 134, for example in scale form, can be formed or have been previously formed on relevant substrates or substrate layers, e.g., as illustrated on substrate layer 104.

[0183] Instead or additionally, the alignment may comprise activating at least two microscanner systems that are not directly adjacent in the layer arrangement, wherein the substrate corresponding to the first substrate layer ("first") and thus the radiation sources 120 are aligned with respect to at least one, in particular all, of the other substrates based on a radiation pattern generated overall by the activated radiation sources. This is an advantageous method for achieving particularly high alignment precision, particularly in connection with the mutual alignment of partial stacks 201 to 203.

[0184] Once the layered assembly is complete, it can be tested as a whole in a test process 325. For this purpose, its thickness, particularly its maximum thickness, is measured and compared with a previously defined tolerance criterion, such as a permissible tolerance range for the thickness. If the tolerance criterion is not met (330 - no), the layered assembly as a whole is rejected as defective (350).

[0185] Otherwise (330 - yes), the method continues with a test process 335, in which the microscanner systems 100 formed in the layer arrangement are tested individually, but preferably simultaneously, at the layer arrangement level (i.e., in the case of wafers, at the wafer level). If defects are detected in certain microscanner systems 100, these can be marked as faulty and / or classified as defective in associated data structures.

[0186] Then, in a singulation process 340, the completed layer arrangement 200 is singulated into the individual, already tested, microscanner systems 100 contained therein. This can be done, in particular, using a sawing process. Such sawing processes, e.g., using diamond-coated saws, can in particular correspond to those known from semiconductor technology for singulating semiconductor wafers into individual chips.

[0187] Microscanner systems previously marked or classified as defective can then be individually selected, in particular rejected, in a subsequent selection process 345.

[0188] Fig. 7 schematically illustrates, according to various embodiments (cf. Fig. 8 and Fig. 9), an image projection device 400 with a projection unit 405 based on a plurality of multi-beam microscanner systems 100. In addition to the projection unit 405, the image projection device 400 additionally has, in a common housing 410, a signal processing unit 415 in which images to be projected by the projection unit into a projection field 420, e.g., still images or moving images (e.g., videos or animations), can be processed based on their associated image data, for example for rendering or further image processing processes, such as filtering, color adjustments, resolution adjustments, etc. In addition, the image projection device 400 can also have further (in Fig.7 not shown) components, such as a communication interface for receiving image data representing the images to be projected or a power supply unit, such as a battery, for supplying the image projection device 400 with power.

[0189] Fig. 8 illustrates a first embodiment 500 of the projection unit 405 from Fig. 7, in which 100 differently colored MEMS projectors are provided for each microscanner system. In the projection unit 405, several multi-beam microscanner systems 100 are arranged in a grid pattern, e.g., as shown in Fig. 1A. In this example, each of the microscanner systems 100 has three different MEMS projectors 100a. In particular, they can be selected so that together they span an RGB color space, so that each microscanner system 100 has a MEMS projector 100a-R for "red" color, a MEMS projector 100a-G for "yellow" color and a MEMS projector 100a-B for "blue" color, which together can project a color-variable pixel (image point), the color of which can be variably determined depending on the control of the individual MEMS projectors by superimposing their respective emitted beams, in particular also time-dependently.By means of the control, the respective intensity of the radiation emitted by the MEMS projectors can be adjusted. Due to their monolithic design, the microscanner systems 100 each form a "tile" from which the grid-like arrangement is composed as a "tiling". Each tile can thus be understood as the source of a color-variable "pixel" and each MEMS projector 100a therein as the source of a subpixel of a subpixel color corresponding to the emission color of the MEMS projector 100a. Instead of the 3 x 3 tiling shown in Fig. 5, other tilings can also be used, so that matrix-shaped n x m tilings with n, me ;; are possible here. Furthermore, non-matrix-shaped arrangements are also conceivable. Each MEMS projector 100a can be configured to emit only monochrome radiation. Instead, it is also possible for it to emit radiation at least predominantly from a matrix focused on one color (e.g.(in this case red, yellow, or blue) limited wavelength range.

[0190] Fig. 9 illustrates a second embodiment 600 of the projection unit from Fig. 7, in which each microscanner system 100 has only MEMS projectors 100a of the same color, but which otherwise can correspond to the first embodiment 500 from Fig. 8. Each tile thus provides only one "color."

[0191] In both embodiments 500 and 600, the individual microscanner systems 100 can be present as separate components that have been combined to form the arrangement in the sense of an assembly. However, it is also possible for all or at least a subset of two or more of the microscanner systems 100 to still be monolithically integrated within a layered arrangement 200, i.e., they have not been separated from it.

[0192] LIST OF REFERENCE SYMBOLS

[0193] 100 micro scanner system

[0194] 100a MEMS projector

[0195] 100a-R MEMS projector for red radiation emission

[0196] 100a-G MEMS projector for yellow radiation emission

[0197] 100a-B MEMS projector for emitting blue radiation101 Stacking direction

[0198] 102 substrate layer with driver circuits

[0199] 102a Driver circuit for driving the deflection element

[0200] 102b Driver circuit for laser device

[0201] 104 “first” substrate layer with laser device

[0202] 104a Cavity for holding the laser device

[0203] 106 Substrate layer with collimator for first oscillation axis

[0204] 108 Substrate layer as spacer layer

[0205] 110 Substrate layer with collimator for a second oscillation axis

[0206] 112 “second” substrate layer with deflection element

[0207] 112a Deflection element

[0208] 112b Cavity for receiving the deflection element

[0209] 112c axis of symmetry

[0210] 112d Opening in the deflection element

[0211] 114 Substrate layer as lid for the cavity with deflection element

[0212] 116 Substrate layer with first and second axicon

[0213] 118 Substrate layer with third axicon or convex lens

[0214] 120 Radiation source, in particular laser device

[0215] 120a Radiation emitters, in particular laser diodes

[0216] 120b optical conductors

[0217] 122 electrical cable for connecting the laser device

[0218] 124a-c electrical contacts

[0219] 126 electrical cable for connecting a drive device for the

[0220] deflection element

[0221] 128 electrically conductive connection bonds

[0222] 130 electromagnetic radiation, especially (laser) beams

[0223] 130-i electromagnetic beam of the i-th radiation source

[0224] 132 adjustment marks

[0225] 134 Adjustment accuracy feature

[0226] 136 Cooling element

[0227] 200 substrate stacks or layer arrangements, in particular wafer stacks

[0228] (Wafer stack) 201-203 partial layer arrangements

[0229] 300 Manufacturing processes for microscanner systems with substrate stack or layer arrangement as intermediate product

[0230] 305-350 Processes within the scope of procedure 300 400 Image projection device

[0231] 405 Projection unit

[0232] 405a, b various embodiments of the projection unit 405

[0233] 410 housing

[0234] 415 Signal processing unit 420 Projection field, superposition of the observation fields of the individual

[0235] Microscanner systems of the image projection device

[0236] 500 first embodiment of the projection unit 405

[0237] 600 second embodiment of the projection unit 405

Claims

CLAIMS 1. A microscanner system (100) for projecting electromagnetic radiation (130) into an observation field, wherein: the microscanner system (100) comprises a substrate stack with a plurality of substrate layers stacked one on top of the other along a stacking direction (101); a number N of radiation sources (120) for generating the electromagnetic radiation (130) are arranged in or on a first substrate layer (104) of the substrate stack, where N > 1; where: if N = 1, a second substrate layer (112) of the substrate stack comprises a MEMS with at least one deflection element (112a) arranged in a beam path of the electromagnetic radiation (130) and suspended so as to be capable of rotational vibration about at least one oscillation axis for deflecting at least one electromagnetic beam emittable by the radiation source (120) in a directionally variable manner; and if N > 1, the microscanner system is multi-beam;the substrate stack is monolithic; the N radiation sources are each configured to emit a respective electromagnetic beam (130-i) as a radiation component of the electromagnetic radiation (130); and a second substrate layer (112) of the substrate stack has, for each radiation source (120), an associated MEMS with at least one deflection element (112a) arranged in the beam path of the electromagnetic beam (130i) of the respective radiation source and suspended so as to be capable of rotational vibration about at least one oscillation axis, for deflecting an electromagnetic beam emittable by the respective radiation source (120) in a directionally variable manner.

2. Microscanner system (100) according to claim 1, wherein in the case N = 1: the radiation source (120) is configured to generate the electromagnetic radiation generated by it at least predominantly as a focused beam with a beam direction deviating from the stacking direction (101) of the substrate stack by an angle of maximum 10°; and in the case N > 1: at least one of the radiation sources (120) or the multi-beam microscanner system (100) as a whole is configured to emit the electromagnetic radiation generated by it at least predominantly as a bundled beam with a beam direction deviating from the stacking direction (101) of the substrate stack by an angle of maximum 10°.

3. Microscanner system (100) according to one of the preceding claims, wherein the substrate stack has at least one further substrate layer (106; 110; 116; 118), in or on which, in the case N = 1: a beam-shaping optics for beam shaping is formed, which is configured to shape the at least one electromagnetic beam (130) before and / or after its deflection by the deflection element (112a); and in the case N > 1: for each radiation source, a beam-shaping optics is formed for beam shaping, which is assigned to this individually or jointly with at least one other radiation source and is configured to shape the electromagnetic beam (130-i) of the respective radiation source (120) before and / or after its deflection by the deflection element (112a) assigned to the respective radiation source.

4. Microscanner system (100) according to claim 3, wherein the substrate stack comprises, as each such further substrate layer, at least one third substrate layer (106; 110) with, in the case N = 1: a first beam-shaping optics formed therein for beam shaping, wherein the first beam-shaping optics is configured to shape the at least one electromagnetic beam (130) before its deflection by the deflection element (112a); and in the case N > 1: each radiation source (120) of a first beam-shaping optics formed therein which is assigned to it individually or jointly with at least one other radiation source Beam-shaping optics for beam shaping, wherein the first beam-shaping optics are each configured to shape the electromagnetic beam (130-i) of the respective associated radiation source (120) before it is deflected by the deflection element (112a) associated with the respective radiation source (120).

5. Microscanner system (100) according to claim 3 or 4, wherein the substrate stack has, as each such further substrate layer, at least one fourth substrate layer (116; 118) with, in the case N = 1: a second beam-shaping optic (116a, 118) formed therein for beam shaping, wherein the second beam-shaping optic (116a, 118) is configured to shape the at least one electromagnetic beam (130) after its deflection by the deflection element (112a); and in the case N > 1: each radiation source (120) has a second beam-shaping optical unit (116a, 118) formed therein for beam shaping, wherein the second beam-shaping optical units (116a, 118) are each configured to shape the at least one electromagnetic beam (130) of the respective associated radiation source after its deflection by the deflection element (112a) associated with the respective radiation source (120).

6. The microscanner system (100) according to any one of claims 3 to 5, wherein, in the case N = 1: the beam-shaping optics or at least one of the beam-shaping optics comprises an axicon, a parabolic mirror, and / or a planar deflecting mirror for at least partially beam-shaping the electromagnetic beam; and, in the case N > 1: at least one of the beam-shaping optics assigned to a respective radiation source (120) comprises an axicon, a parabolic mirror, and / or a planar deflecting mirror for at least partially beam-shaping the electromagnetic beam emitted by the assigned radiation source (120).

7. Microscanner system (100) according to one of the preceding claims, wherein the substrate stack has at least one fifth substrate layer (102), in or on which a driver circuit (102b) is formed in the case N = 1: for electrically controlling the radiation source (120) and / or a driver circuit (102a) is formed for controlling a drive of a rotary oscillating movement of the deflection element (112a) about the at least one oscillation axis; and in the case N > 1: for electrically controlling one or more of the radiation sources (120) and / or at least one driver circuit (102a) is formed for controlling one or more drives of the rotary oscillating movements of one or more of the deflection elements (112a) about their respective at least one oscillation axis.

8. Microscanner system (100) according to claim 7, wherein, viewed along the stacking direction (101), the first substrate layer (104) is arranged lying between the fifth substrate layer (102) and the second substrate layer (112).

9. The microscanner system (100) according to claim 8, wherein: in the case N = 1: the fifth substrate layer (102) has the driver circuit (102a) for controlling a drive for the oscillating movement of the deflection element (112a); the second substrate layer (112) has at least one actuator for driving the oscillating movement of the deflection element (112a); and the first substrate layer (104) has an electrical line running through it for the direct or indirect electrical connection of the actuator to the driver circuit (102a) for controlling the drive; and in the case N > 1: the fifth substrate layer (102) has the associated driver circuit (102a) for each deflection element for controlling a drive for the oscillating movement of the respective deflection element (112a); the second substrate layer (112) has at least one actuator for each deflection element for driving the oscillating movement of the respective deflection element (112a); and the first substrate layer (104) has an electrical line running through it for each actuator for the direct or indirect electrical connection of the actuator to the driver circuit (102a) for controlling the drive.

10. The microscanner system (100) according to one of the preceding claims, wherein the substrate stack has at least one sixth substrate layer (114), by means of which, in the case N = 1: a first cavity (112b) formed in the substrate stack is hermetically sealed; and in the case N > 1: a first cavity (112b) associated with each deflection element is formed in the substrate stack and hermetically sealed.

11. The microscanner system (100) according to claim 10, wherein, in the case N = 1: the deflection element (112a) or at least one of the deflection elements is arranged in the hermetically sealed first cavity (112b) and is suspended so as to be capable of rotational vibration about the at least one vibration axis; and, in the case N > 1: each of these deflection elements is arranged in the respective first cavity (112b) assigned to it and is suspended so as to be capable of rotational vibration about the at least one vibration axis.

12. Microscanner system (100) according to one of the preceding claims, wherein in the case N = 1: the radiation source (120) is arranged at least partially within a second cavity (104a) formed in the first substrate layer (104); and in the case N > 1: at least one of the radiation sources (120) is arranged at least partially within a second cavity (104a) formed in the first substrate layer (104) for each radiation source individually or for several of the radiation sources are arranged in a second cavity (104a).

13. The microscanner system (100) according to claim 12, wherein, in the case N = 1: a surface section of a side wall of the second cavity (104a) has at least one electrically conductive layer for producing a respective electrical connection of the radiation source (120); and, in the case N > 1: a surface section of a side wall of at least one second cavity (104a) has at least one electrically conductive layer for producing a respective electrical connection of at least one radiation source (120) arranged at least partially in this respective second cavity.

14. The microscanner system (100) according to any one of claims 10 to 13, wherein, in the case N = 1: the first cavity (112b) and / or the second cavity (104a) contains a gas at a gas pressure below normal pressure, which consists at least predominantly of a protective gas, or is evacuated; in the case N > 1: at least one first cavity (112b) or second cavity (104a) is evacuated or contains a gas at a gas pressure below normal pressure, which consists at least predominantly of a protective gas.

15. Microscanner system (100) according to one of the preceding claims, further comprising: a seventh layer, which in the case N = 1: is arranged in the beam path of the radiation source and is designed as a diffusing screen or a ground glass screen such that when it is irradiated with the beam of the radiation source, an intermediate image is formed on the seventh layer; in the case N > 1: is arranged in the respective beam paths of at least two of the radiation sources and is designed as a diffusing screen or a ground glass screen such that when it is irradiated with the beams of these at least two radiation sources at the seventh layer to create an intermediate image; and a projection optics for projecting the intermediate image into the observation field.

16. Microscanner system (100) according to one of the preceding claims, wherein in the case N = 1: the radiation source (120) for at least partially generating the electromagnetic radiation (130) has one or more of the following radiation emitters: edge-emitting laser, surface-emitting laser, superluminescent diode, mini-LED, micro-LED; and in the case N > 1: at least one of the radiation sources (120) for at least partially generating its respective electromagnetic beam (130-i) has one or more of the following radiation emitters (120a): edge-emitting laser, surface-emitting laser, superluminescent diode, mini-LED, micro-LED.

17. Microscanner system (100) according to one of the preceding claims, wherein in the case N = 1: the deflection element (112a) has a rotational symmetry with respect to an axis of symmetry (112c) running parallel to the stacking direction (101) and the radiation source (120) is designed such that the electromagnetic beam (130) generated by it during its operation runs along the axis of symmetry (112c) of the deflection element (112a) and through an opening (112d) therein; and in the case N > 1: at least one deflection element (112a) has a rotational symmetry with respect to an axis of symmetry (112c) running parallel to the stacking direction (101), and the radiation source (120) associated with the respective deflection element is designed such that the electromagnetic beam (130) generated by it during operation runs along the axis of symmetry (112c) of the associated deflection element (112a) and through an opening (112d) therein.

18. Microscanner system (100) according to one of claims 1 to 16, wherein in the case N = 1: the microscanner system is designed such that, during operation of the radiation source, the electromagnetic beam (130) generated by it passes past the deflection element through an opening in the second substrate layer to a reflective surface, at which the beam is deflected onto the deflection element in order to be reflected there; and in the case N > 1: the microscanner system is designed such that, for at least one radiation source, during operation, the electromagnetic beam generated by it passes past the deflection element assigned to it through an opening in the second substrate layer to a reflective surface, at which the beam is deflected onto this deflection element in order to be reflected there.

19. Microscanner system (100) according to one of the preceding claims, wherein one or more of the substrate layers each have at least one alignment mark (132) by means of which at least two of the substrate layers of the microscanner system (100) are aligned with one another in a dimension running transversely to the stacking direction (101).

20. Microscanner system (100) according to one of the preceding claims, wherein one or more of the substrate layers each have at least one alignment accuracy feature (134) by means of which the accuracy of the relative alignment of at least two of the substrate layers of the microscanner system (100) with respect to at least one spatial dimension can be determined.

21. Microscanner system (100) according to one of the preceding claims, further comprising one or more cooling elements (136) which each extend into or through at least two of the substrate layers and are formed from a material which has an increased thermal conductivity compared to its respective immediate surroundings in the substrate stack.

22. Microscanner system (100) according to one of the preceding claims, in the case N > 1 , wherein at least one of the radiation sources (120) is configured to emit its respective electromagnetic beam (130-i) in a wavelength range that differs from a wavelength range of the beam (130-i) of at least one radiation source (120) differs at least proportionally.

23. Microscanner system according to claim 22, wherein the microscanner system has at least two monochromatic radiation sources (120) whose emission wavelengths are selected differently so that together they span an at least two-dimensional color space. 24 Microscanner system (100) according to claim 22 or 23 in combination with claim 2, wherein the radiation sources (120) are designed such that the beam directions of their respective bundled beams run parallel and adjacent to one another such that the bundled beams of the radiation sources (120) are perceptible in the observation field as mutually adjacent, differently colored subpixels of a pixel formed by the subpixels as a whole.

25. Microscanner system (100) according to one of the preceding claims for the case N > 1, wherein all radiation sources (120) are configured to emit their electromagnetic beam (130-i) in a wavelength range that is the same for all radiation sources and has a width of a maximum of 100 nm, in particular a maximum of 50 nm, or monochromely at a wavelength that is the same for all radiation sources (120).

26. A stack (200) comprising a plurality of substrates stacked one upon another along a stacking direction (101), which substrates are fastened to one another at the respective interfaces of adjacent substrates by means of a respective bond connection; wherein, in the case of N = 1: the stack is a substrate stack (200) in which a plurality of microscanner systems (100) according to one of the preceding claims are arranged adjacent to one another in such a way that the microscanner systems can each be obtained by singulation from the substrate stack (200); and in each of the microscanner systems (100), its respective substrate stack of substrate layers contains an associated section of the substrate stack (200), wherein the substrates of the substrate stack (200) each form one of the substrate layers; and in the case N > 1: the stack is a layer arrangement (200) in which a plurality of multi-beam microscanner systems (100) according to one of the preceding claims are formed adjacent to one another in such a way that the multi-beam microscanner systems can each be obtained from the layer arrangement (200) by isolating them individually or in at least two groups of two or more mutually adjacent microscanner systems; and each of the multi-beam microscanner systems (100) contains a respective section of the layer arrangement (200), so that the regions of the substrates of the layer arrangement (200) contained in the respective section and stacked one above the other each form one of the substrate layers of the microscanner system (100) formed in the respective section.

27. Image projection device (400) for projecting an image into a projection field (420), wherein the image projection device (400) comprises a plurality of multi-beam microscanner systems (100) according to one of claims 1 to 25, each configured to display one pixel of the image to be projected, for the case N > 1.

28. Image projection device (400) according to claim 27, comprising one or more layer arrangements (200) according to claim 25 for the case N > 1; wherein each of the layer arrangements (200) contains a respective number of at least two of the microscanner systems (100) of the image projection device (400).

29. A method (300) for manufacturing a plurality of microscanner systems (100) according to any one of claims 1 to 25, wherein the method (300) comprises: in the case N = 1: Stacking (305, ..., 320) a plurality of substrates along a stacking direction (101) to produce a stack formed as a substrate stack (200) according to claim 25, wherein adjacent substrates in the substrate stack (200) are fastened to one another at their interface therebetween; and Separating (330) at least two of the microscanner systems from the substrate stack; and in the case N > 1 : Stacking a plurality of substrates along a stacking direction to produce a stack formed as a layer arrangement according to claim 26, wherein adjacent substrates in the layer arrangement are fastened to one another at their intermediate interface, in particular by means of a respective bond connection; and (iii) separating at least two of the microscanner systems from the layer arrangement individually or into at least two groups each comprising two or more adjacent microscanner systems, in order to obtain individual microscanner systems or units corresponding to the groups, each comprising a plurality of microscanner systems.

30. The method (300) of claim 29, wherein the stacking (305, ..., 320) comprises: Forming at least two partial substrate stacks (WS1, ..., WS3) by stacking two or more of the substrates per partial substrate stack (WS1, ..., WS3) on top of each other, wherein adjacent substrates in each partial substrate stack (200) are fastened to one another at their intermediate interface by means of a respective bond connection; and stacking and fastening the partial substrate stacks (WS1, ..., WS3) and optionally further substrates on top of each other in order to form the substrate stack (200) as a whole.

31. Method (300) according to claim 29 or 30, wherein, in the case N = 1: in or on at least one selected substrate layer (104), an alignment mark (132) is generated, and at least one other substrate layer (106) is adjusted with respect to its position relative to the selected substrate layer(s) (104) by means of the respective alignment mark (132) during formation of the substrate stack; and, in the case N > 1: in or on a first substrate of the layer arrangement (200), for each of the multi-beam microscanner systems (100) formed in the layer arrangement (200), the radiation sources (120) respectively associated with it, which each have one or more radiation emitters (120a), are formed in situ or individually or combined, mounted as a prefabricated component; and during the production of the substrate stack, the first substrate thus equipped with the radiation sources (120) of the multi-beam microscanner systems (100) is adjusted as a whole relative to a second substrate.

32. Method (300) according to one of claims 29 to 31, wherein before the singulation (340): in the case N = 1: in or on the first substrate layer of the substrate stack (200), for each of the microscanner systems (100) formed in the substrate stack (200), the radiation source (120) assigned to it, which has one or more radiation emitters (120a), is formed in situ or mounted as a prefabricated component; and during the production of the substrate stack, the first substrate layer (104) thus equipped with the radiation sources (120) of the microscanner systems (100) is adjusted as a whole relative to the second substrate layer (112);and in the case N > 1: in or on the first substrate of the layer arrangement (200), for each of the multi-beam micro-scanner systems (100) formed in the layer arrangement (200), the radiation sources (120) respectively assigned to it, which each have one or more radiation emitters (120a), are formed in situ or mounted individually or combined as a prefabricated component; and during the production of the substrate stack, the first substrate thus equipped with the radiation sources (120) of the multi-beam micro-scanner systems (100) is adjusted as a whole relative to a second substrate.; 33. The method (300) of claim 32, wherein the adjusting comprises: in case N = 1: Activating the respective radiation sources of at least two microscanner systems not directly adjacent in the substrate stack; and aligning the first substrate layer with at least one further substrate layer based on a radiation pattern generated overall by the activated radiation sources; and in the case N > 1: Activating the respective radiation sources of at least two microscanner systems that are not directly adjacent in the layer arrangement; and Aligning the first substrate to at least one of the further substrates based on a radiation pattern generated overall by the activated radiation sources.

34. The method (300) according to any one of claims 29 to 33, further comprising: measuring (325) a thickness of the produced stack prior to singulation; comparing (330) the measured thickness with a tolerance criterion defined in this regard; if the measured thickness has a value beyond a value classified as tolerable by the tolerance criterion, selecting (350) the stack and omitting the singulation (340); and otherwise performing the singulation (340).

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