Projection optics and method for producing an optical structure

Abstract

Projection optics (100a-c, 500) with the following features: a first layer (110, 310, 522) of a first cured material, wherein the first layer has a first optical lens surface (112, 312, 524) on a first side of the first layer at an optical axis (130, 360, 526) of the projection optics, and wherein the first layer has a planar portion (114, 528) on a second side of the first layer, opposite the first side of the first layer, at the optical axis; and a second layer (120, 340, 530) of a second cured material, wherein the second layer has a planar portion (122, 532) on a first side of the second layer at the optical axis (130, 360, 526), ​​and wherein the second layer has a second optical lens surface (124, 344, 534) on a second side of the second layer, opposite the first side of the second layer, at the optical axis; wherein the planar portion (114, 528) of the first layer is adjacent to the planar portion (122, 532) of the second layer at the optical axis, or wherein the planar portion (114, 528) of the first layer is separated from the planar portion (122, 532) of the second layer at the optical axis only by one or more coating layers (140, 330, 544); and wherein the projection optics has a lateral size in a plane of the first layer (110, 310, 522) of at least 100 µm or of at least 200 µm or of at least 300 µm or of at least 0.5 mm and of at most 2 mm or of at most 3 mm or of at most 5 mm; and / or wherein the projection optics has a height perpendicular to the first and second layers (120, 340, 530) of at least 0.5 mm or of at least 1 mm or of at least 2 mm and of at most 2 mm or of at most 3 mm or of at most 5 mm.

Description

Technical area

[0001] Embodiments according to the invention relate to projection optics and methods for producing optical structures. Background of the invention

[0002] Modern camera systems face ever-increasing demands for miniaturization, higher performance, and cost reduction. For example, camera systems for medical applications may have to meet strict constraints regarding their dimensions to be suitable for medical purposes, where the camera system is inserted into the human body to assist in a surgery or to determine the next steps for a given treatment. Despite these limitations, it may be important that the small camera system is capable of delivering high-quality images to provide the best possible support to the treating physician. At the same time, there is a need to create such systems with low-complexity manufacturing processes to keep costs low.

[0003] At this point, reference is made to a conventional approach according to US 8936371 B2. US 8936371 B2 relates to a wafer-level lens comprising at least one lens module with a substrate and a plurality of lenses formed on the substrate. The wafer-level lens comprises a black resist layer formed on the surface of the lens module or on the surface of the substrate, wherein the black resist layer is formed with a pattern having an opening at a portion intersecting the optical axis of the lens to prevent the generation of optical defects.

[0004] Another approach can be found in US 2013 / 265459 A1. US 2013 / 265459 A1 deals with imaging devices formed from a plurality of imagers with different imaging characteristics. The images generated by the plurality of imagers are processed to obtain an improved image compared to the images captured by the imagers. Summary of the invention

[0005] It is therefore desirable to obtain a concept for an optical structure and for its manufacture as well as a projection optics that provides a better compromise between size, behavior and complexity and thus the costs of the optical structure or the projection optics and their respective manufacture.

[0006] This is achieved by the subject matter of the independent claims of the present application.

[0007] Further embodiments according to the invention are defined by the subject matter of the dependent claims of the present application.

[0008] The present invention thus provides projection optics and methods for manufacturing optical structures according to the independent patent claims. Further developments of the invention are defined in the dependent claims. All embodiments and examples of the description that do not fall within the scope of the claims are not part of the invention and serve only for illustrative purposes.

[0009] Embodiments of the present invention include a method of manufacturing an optical structure, the method comprising forming a first layer of the optical structure, wherein forming the first layer comprises forming and curing a first curable material on a first mold structure to form a first layer such that, on a first side of the first layer on which the first layer is adjacent to the first mold structure, a first optical lens surface is formed. The method further includes providing a second layer of the optical structure on a second side, opposite the first side, of the first layer, while the first layer is adjacent to the first mold structure on the first side of the first layer.

[0010] The inventors have recognized that a stack of layers of an optical structure manufactured by molding processes can also be processed during manufacturing on a back side opposite a side subjected to a first molding step, namely by using the mold structure used for the first molding step at the time of processing the back side, thereby avoiding an additional substrate on the back side. This means that the mold structure can have an uneven, e.g., non-planar, surface for forming or replicating a first optical lens surface of a first layer of the optical structure on a first side of the first layer. On the opposite second side of the first layer, at least one processing step can be performed while the first mold structure has not yet been removed, so as to function as a kind of handle.For example, this processing may include replication of another layer. For example, a second layer may be provided on the second side without any substrate between the first layer and the second layer. Thus, for example, the second layer may be provided directly on the first layer, or the two layers may optionally be separated only by one or more coating layers. For this manufacturing step, the first layer is still adjacent to the first mold structure, which is why a stable base for precise application of the second layer and / or the one or more coating layers can be provided.

[0011] The inventors realized that this approach allows for the simple production of optical structures without the need for intermediate substrates. For example, for mechanical reasons, substrates used in conventional approaches are limited to minimal thicknesses, which hinders the desired miniaturization of the optical structure. In simple terms, the inventors realized that the mold structure, which may be required anyway in conventional approaches to form a lens surface, can be used twice, not only for forming the lens but also as a replacement substrate. Consequently, fewer elements are required for the manufacturing process, thereby reducing costs.

[0012] According to embodiments of the invention, providing the second layer comprises forming and curing a second curable material on the second side of the first layer using a second mold structure to form the second layer, such that a second optical lens surface is formed on a second side of the second layer on which the second layer is adjacent to the second mold structure and which faces away from the second side of the first layer, and such that the second optical lens surface is aligned with the first optical lens surface and an optical axis of the optical structure.

[0013] In simple terms, and as an example, the inventors have recognized that the approach for forming the first optical lens surface can be mirrored for forming the second optical lens surface by sandwiching the layer stack comprising the first and second layers between the first mold structure and the second mold structure. Consequently, it is possible to form optical lens surfaces on opposite surfaces of the layer stack, namely the first side of the first layer and the second side of the second layer, without having to introduce any intermediate substrate. Again, the first mold structure can provide stability for the cured first layer at the time of forming and curing the second curable material.

[0014] As mentioned above, the first and second layers can be directly adjacent to one another. However, it should again be noted that, for example, prior to providing a second layer, one or more coating layers can be provided and optionally structured on the second surface of the first layer. Optionally, such a coating layer can form a filter or an aperture, or a filter combined with an aperture, of the projection optics or optical structure according to the invention.

[0015] Thus, embodiments include a projection optic comprising a first layer of a first cured material, the first layer having a first optical lens surface on a first side of the first layer at an optical axis of the projection optic and a planar portion on a second side of the first layer opposite the first side of the first layer at the optical axis. The projection optic further comprises a second layer of a second cured material, the second layer having a planar portion on a first side of the second layer at the optical axis and a second optical lens surface on a second side of the second layer opposite the first side of the second layer at the optical axis.

[0016] Furthermore, the planar portion of the first layer is adjacent to the planar portion of the second layer at the optical axis or the planar portion of the first layer is separated from the planar portion of the second layer at the optical axis only by the one or more coating layers.

[0017] Consequently, a method according to the invention may comprise removing the first and / or second mold structure after curing the first and second layers to create the previously explained projection optics.

[0018] Furthermore, the introduction or inclusion of the first and second curable materials between the first and second mold structures for the production of the first and second layers enables precise alignment of the first and second optical lens surfaces and the optical axis of the projection optics to be provided.

[0019] Additionally, according to embodiments, the projection optics may comprise a plurality of layer stacks. As explained above, a layer stack may comprise a first and a second two-sided replicated layer with optical lens surfaces on opposite sides. Consequently, the projection optics may comprise a first further layer and a second further layer, which may be manufactured like the first and second layers, wherein such a further layer stack may, for example, be connected to the second layer on the second side of the second layer, such that the first further layer adjoins the second layer. In this way, a projection optics may be created with at least two two-sided replicated layer stacks comprising at least four optical elements in the form of optical lens surfaces.Consequently, a projection optics according to the invention can be formed from a plurality of modules having first and second layers, wherein the modules can be produced in a similar manufacturing process, which can reduce the cost and complexity of a corresponding manufacturing process.

[0020] It should be noted that additional coating layers may also be provided between such additional layers. With regard to any of the coating layers, the inventors have recognized that such coating layers can provide apertures and / or filters to further increase the functional density of the projection optics or optical structure.

[0021] According to further embodiments, the projection optics may comprise a third layer of a third cured material, wherein the third layer is adjacent to the second layer on the second side of the second layer and on a first side of the third layer, or wherein the third layer is adjacent to the second further layer on a second side of the second further layer and on a first side of the third layer. Additionally, the third layer may comprise a third optical lens surface on a second side, opposite the first side, of the third layer at the optical axis of the projection optics.

[0022] Consequently, for creating such a third layer, a method according to the invention may comprise removing the second mold structure from the second layer and forming and curing a third curable material on the second side of the second layer between the second layer and a third mold structure to form the third layer, such that, on a first side of the third layer, the third layer is adjacent to the second layer, and on a second side of the third layer facing away from the first side of the third layer and on which the third layer is adjacent to the third mold structure, a third optical lens surface is formed, and such that the first optical lens surface is aligned with the third optical lens surface at an optical axis of the optical structure.

[0023] Consequently, a third layer can be provided on a second further layer of a projection optics or optical structure according to the invention.

[0024] Therefore, in a manufacturing process according to the invention, further layers can be stacked on top of first and second layers. Therefore, in simple terms, one of the mold structures can be removed so that the next curable material can be applied to the layer and formed using a subsequent mold structure. In simple terms, to form the next layer, for example, such a third layer, the layer stack can be reinserted between the first mold structure and the next, for example, third, mold structure.

[0025] In general, embodiments according to the invention may enable the use of a precisely clamped or fixed first mold structure for the alignment of a plurality or even all further layers replicated and / or bonded on the first mold structure. This may simplify the manufacturing process and may enable highly precise alignment of the layers. Therefore, additional alignment structures may be arranged, for example, adjacent to an optical axis of the projection optics or the optical structure to further improve alignment of optical elements, such as lens surfaces. Alternatively, optical alignment methods may be used.

[0026] Furthermore, embodiments may include compensation structures configured to compensate for manufacturing tolerances and / or to adjust or provide a focal point of the inventive structures or optics. First, it should be noted that, in order to reduce costs, the fabrication of the inventive optics or structures may be performed in parallel for a plurality of such devices, for example, at a wafer level and / or in an array arrangement.

[0027] The inventors have recognized that, based on a collection of data for respective optics or structures, individual or generic compensation structures can be used for compensation. For example, parameter sets characterizing a respective structure or optic can be obtained through testing. If, in simple terms, these parameters are similar for the majority of optics or structures manufactured in parallel, a generic compensation structure can be used for each of the structures or optics. On the other hand, if such an approach would result in excessive manufacturing rejects, an individual compensation structure can be manufactured for each of the optics or structures and connected to the respective optic or structure.Alternatively, a compensation structure that best fits a particular projection optic or structure according to the invention can be used from a plurality of different compensation structures.

[0028] According to embodiments, a selection of a respective approach, namely the use of generic compensation structures or individual compensation structures, can be made on a per-batch basis. This can enable the delivery of a highly optimized manufacturing process. Short description of the drawings

[0029] The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the invention are described with reference to the following drawings, in which: Fig. 1 ac show schematic views of projection optics with additional optional features according to embodiments of the invention; Fig. 2 at show schematic side views of optical structures and components thereof, visualizing methods for manufacturing an optical structure according to embodiments of the invention; and Fig. 3 shows schematic views of another projection optics according to embodiments of the invention. Detailed description of the implementation examples

[0030] Identical or equivalent elements or elements with identical or equivalent functionality are designated by identical or equivalent reference numerals in the following description, even if they appear in different figures.

[0031] In the following description, numerous details are set forth in order to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, to avoid obscuring embodiments of the present invention. Furthermore, features of the various embodiments described below may be combined with one another unless specifically noted otherwise.

[0032] Furthermore, for the description of embodiments, a first side of an element may be opposite a second side of the element, and the sides of consecutive elements may be oriented such that a first side of one element is adjacent to a second side of another element. Thus, the first sides of elements may be oriented toward the same directions, and second sides of elements may be oriented toward another, same direction, opposite to the orientation of the first sides. In simple terms, a first side may be a top side and a second side may be a bottom side of an element.

[0033] First, it should be noted that embodiments according to the invention comprise optical systems, for example in the form of projection optics and / or optical structures. Although some embodiments are discussed with respect to projection optics or a manufacturing method for an optical structure, it should be noted that any features, details, and functionalities of a respective projection optics and / or a manufacturing method thereof can be used in a similar, identical, or similar manner for an optical structure and / or a manufacturing method thereof, and vice versa. Furthermore, the inventive arrangement of a first and a second layer can be referred to as a layer stack, or as a two-sided replicated layer.

[0034] It should further be noted that, as used herein, an arrangement of an element on an optical axis or on the optical axis may be understood such that the element is arranged laterally on the optical axis, for example laterally in-plane with respect to a respective layer, for example in a lateral neighborhood of the axis, for example in a lateral adjacent volume perpendicular to the axis.

[0035] The Fig. 1a-c show schematic views of projection optics with additional optional features according to embodiments of the invention. Projection optics 100a-c each comprise a first layer 110 made of a first cured material and a second layer 120 made of a second cured material. The first layer 110 comprises a first optical lens surface 112 on a first side of the first layer at an optical axis 130 of the projection optics. Furthermore, the first layer 110 comprises a planar portion 114 on a second side of the first layer opposite the first side of the first layer at the optical axis 130. Conversely, the second layer 120 comprises a planar portion 122 on a first side of the second layer at the optical axis 130 and a second optical lens surface 124 on a second side of the second layer opposite the first side of the second layer at the optical axis 130. As shown in the Fig. 1a-c, the planar portion 114 of the first layer optionally adjoins the planar portion 122 of the second layer at the optical axis 130.

[0036] However, as an optional feature, the projection optics 100a to 100c each have a coating layer 140. It should be noted that more than one coating layer 140 may be disposed between the first layer 110 and the second layer 120. As shown in the Fig. 1a-c, the coating layer 140 can be a structured coating layer. In the illustrated embodiments, a respective coating layer 140 can form an aperture of a respective projection optics 100a to 100c.

[0037] As a further optional feature, the coating layer or the one or more coating layers may form a filter of a respective projection optics and / or an aperture and a filter of a respective projection optics. Therefore, at the optical axis, the one or more coating layers, for example in the case of a filter, may be arranged between the first layer 110 and a second layer 120, such that the planar portion 114 of the first layer 110 is separated from the planar portion 122 of the second layer 120 at the optical axis 130 only by the one or more coating layers (not shown).It should be emphasized that in such a case, the coating layer does not have to be a filter, as mentioned above as an example, but the coating layer can, for example, just be any thin layer suitable to provide any desired functionality for the projection optics.

[0038] As previously explained, the layer stack comprising layers 110 and 120 can be manufactured with small dimensions because, unlike conventional approaches, no substrate is disposed between the first and second layers, allowing the layer stack to be miniaturized. Furthermore, the inventors have realized that even an additional coating layer can be disposed between the first and second layers. Therefore, in simple terms, not only is a substrate eliminated, which would increase the overall size of the structure, but a further functional layer, providing, for example, the functionality of an aperture or a filter, or even both, is additionally included, with, for example, only a minor impact on the dimensions of the projection optics.

[0039] As an optional feature, the projection optics 110 may include a second layer stack, or in other words, a second two-sided replicated layer. The projection optics 100c includes a first further layer 110c made of a first further cured material and a second further layer 120c made of a second further cured material. The first further layer 110c includes a first further optical lens surface 112c on a first side of the first further layer at the optical axis 130 of the projection optics and a planar portion 114c on a second side of the first further layer opposite the first side of the first further layer at the optical axis 130.The second further layer 120c has a planar portion 122c on a first side of the second further layer at the optical axis 130 and a second further optical lens surface 124c on a second side of the second further layer opposite the first side of the second further layer at the optical axis 130.

[0040] Furthermore, the planar portion 114c of the first further layer 110c adjoins the planar portion 122c of the second further layer 120c at the optical axis 130. Again, it should be noted that this direct adjoining, as already explained in connection with the first and second layers, is only optional. As a further optional feature, a further coating layer 140c is shown, which is arranged between the first further layer 110c and the second further layer 120c. Again, this further coating layer 140c can be, for example, a structured layer, but can optionally also or alternatively form a filter.

[0041] In general, coating layers according to the embodiments of the invention can, for example, be any thin layer having any suitable functionality. Therefore, again, as explained in connection with the first and second layers, the first further layer 100c can, for example, be separated from the second further layer 120c only by the coating layer 140c at the optical axis. Thus, the further coating layer 140c can be arranged between these planar sections at the optical axis 130, instead of the planar sections 114c and 122c being directly adjacent to one another at the optical axis 130.

[0042] Furthermore, as shown for the projection optics 100c, the first further layer 110c is adjacent to the second layer 120 on the second side of the second layer and on the first side of the first further layer.

[0043] It should be noted that the first and second layers, and the first and second further layers, may, for example, be similar, identical, or completely different layer stacks. It should also be noted that such a structure may enable the provision of a plurality of optical lens surfaces without requiring the inclusion of a conventional substrate. Thus, even complex optical projection paths can be created through the projection optics 110c without having to significantly increase the size of the projection optics.

[0044] For the sake of completeness, it should be noted that more than one further coating layer 140c may be arranged between the first and second further layers. Furthermore, it should be noted that such a further layer stack may also be connected to any additional, for example, third, layer that may be arranged on the second layer 120.

[0045] As shown, as another optional feature, the projection optics 100c includes a cavity 150c between the second optical lens surface 124 and the first optical lens surface 112c at the optical axis 130.

[0046] As a further optional feature, the projection optics 100a to 100c each include an additional layer 160 of an additional cured material adjacent to the first layer 110 on the first side of the first layer and on a second side of the additional layer. Furthermore, the additional layer includes an additional optical lens surface 162 on the second side of the additional layer at the optical axis 130 of the projection optics. Optionally, as shown, a cavity 150 may be present between the first optical lens surface 112 and the additional optical lens surface 162 at the optical axis 130.

[0047] For example, a projection optics according to the invention can optionally have alignment structures for connecting the additional layer 160 to the first layer 110. As an example, alignment structures 170 are shown in Fig. 1c. To further emphasize that this feature is only optional, the alignment structures 170 are only shown in Fig. 1c, but can also be present in the projection optics 100a and 100b. As shown in Fig. 1c, the alignment structures 170 can be arranged, for example, on the first side of the first layer 110 and on the second side of the additional layer 160. The alignment structures 170 are configured to align the first layer 110 and the additional layer 160 such that the first optical lens surface 112 is aligned with the additional optical lens surface 162 at the optical axis 130. As an example, the alignment structures 170 are shown as small pyramid structures, but any shape suitable for aligning the two layers (or any other two layers being joined) can be used.As an example, one of the two layers, either the first layer or the additional layer, may have the alignment structure 170 and the other layer may have a negative shape, or in simple terms a hole, in the shape of the alignment structure, so that after bonding the two layers, the optical lens surfaces are aligned.

[0048] It should be emphasized that embodiments are not limited to such alignment structures. In a manufacturing method according to the invention, layers can be aligned, for example, using optical alignment methods. Furthermore, alignment clamps can also be arranged at outer edges of the respective layer stacks to provide the alignment. Furthermore, it should be noted that alignment can be performed, for example, at a wafer level or at an array level for the production of the projection optics, such that a plurality of devices according to the invention that are manufactured can be aligned simultaneously. Thus, in summary, optical alignment can be performed with alignment structures and / or with mechanical structures, for example clamping structures.

[0049] As in the Fig. 1a and Fig. 1c, the projection optics can optionally comprise a support structure 180, which adjoins the additional layer 160 on a first side, opposite the second side, of the additional layer. The support structure 180 can be, for example, a substrate or a mold structure and / or a mold structure with a planar topology. Therefore, the additional layer can be manufactured, for example, in a conventional manufacturing process on a substrate, e.g., a glass substrate, and the entire structure comprising the additional layer 160 and the substrate can then be connected to the first layer 110. However, instead of using a substrate, a mold structure can be used to manufacture the additional layer 160. Therefore, on a first side of the additional layer 160, a further lens surface formed by a respective mold structure can optionally be arranged.As a further optional feature, the support structure 180 may be a molded structure having a planar topology, which in simple terms acts as a substrate.

[0050] As another optional feature, as in Fig. 1b, the projection optics 100b comprises a third layer 190 of a third cured material. The third layer adjoins the second layer 120 on the second side of the second layer and on a first side of the third layer. Furthermore, the third layer 190 has a third optical lens surface 192 on a second side, opposite the first side, of the third layer at the optical axis 130 of the projection optics. For example, in a projection optics as shown in Fig. 1c, the third layer may be adjacent to the second further layer 120c (not shown) on the second side of the second further layer and on a first side of the third layer.

[0051] The projection optics 100b, as shown in Fig. 1b, can have the functionality of an achromat. Thus, optionally, two consecutive layers of the projection optics can have different optical characteristics, namely in the example shown in Fig. 1b), the second layer 120 and the third layer 190. Consequently, an optical lens surface of a first of the two consecutive layers may have a high refractive index and low dispersion, and an optical lens surface of a second of the two consecutive layers, facing the optical lens surface of the first of the two consecutive layers, may have a low refractive index and high dispersion to form the achromat. Consequently, embodiments according to the invention may make it possible to limit the effect of chromatic and spherical aberrations. Adjacent lens surfaces may thus provide the functionality of a flint glass or a crown glass.

[0052] As another optional feature, as described in the Fig. 1a-c, the projection optics 100a-c / may have a backside structure 200 and a cavity 210. As shown in Fig. 1a, a first surface of the backside structure 200 may be adjacent to the second layer 120 on the second side of the second layer, and the cavity 210 may be arranged between the backside structure 200 and the second optical lens surface at the optical axis 130. Alternatively, as shown in Fig. 1b, a first surface of the backside structure 200 may be adjacent to the third layer 190 on the second side of the third layer, and the cavity 210 may be adjacent between the backside structure 200 and the third optical lens surface 192 at the optical axis 130. As a further optional alternative, as shown in Fig. 1c, a first surface of the backside structure 200 may be adjacent to the second further layer 120c on the second side of the second further layer, and the cavity 210 may be arranged between the backside structure 200 and the second further optical lens surface 124c at the optical axis 130.

[0053] The rear structure can provide mechanical stability to the projection optics. Optionally, as described in the Fig. 1a-c, the backside structure may comprise a backside substrate 202, a filter 204, and a compensation structure 206. The compensation structure 206 may be configured to compensate for manufacturing tolerances and to adjust or improve a focal point of the optical structure. As a result of manufacturing the layers of the projection optics, for example, a thickness thereof may vary within certain tolerances. However, this may degrade a desired beam path through the projection optics and may thus, for example, degrade a desired alignment of beams through the projection optics to a predetermined focal point, e.g., at a position where a sensor is connected to the projection optics. To compensate for such tolerances, the compensation structure 206 may be included in the projection optics.

[0054] As shown, the filter 204 optionally includes a first filter structure 2041 disposed on a first surface of the backside substrate 202 and a second filter structure 2042 disposed on a second surface, opposite the first surface, of the backside substrate 202. The double-sided application of the filter structures can allow for compensation of warping effects during manufacturing, so that the backside substrate 202 and the filter 204 can form a planar structure that can be precisely bonded to the other layers and / or elements of the projection optics.

[0055] For reference, the compensation structure 206 may have a first surface and a second surface, wherein the second surface is opposite the first surface and, as shown in the Fig. 1a-c, the first surface of the compensation structure may adjoin the second filter structure 2042, so that the first filter structure 2041 forms the first surface of the backside structure 200.

[0056] However, it should be noted that according to embodiments, the order of the compensation structure and the backside substrates, along with a filter, is interchangeable. Thus, optionally (not shown), the first filter structure 2041 may be adjacent to the second surface of the compensation structure 206, such that the first surface of the compensation structure forms the first surface of the backside structure 200. Simply put, the backside substrate and the filter comprising the filter structures may, for example, be arranged on the bottom side, and the compensation structure 206 may be arranged on the top side of the backside structure 200.

[0057] Furthermore, it should be noted that according to embodiments, the backside structure 200 may optionally comprise only the compensation structure 206 or only the backside substrate 202 together with the filter 204.

[0058] Furthermore, it should be noted that the filter can optionally have only the first filter structure and no second filter structure. The first filter structure can be arranged on the first surface of the backside substrate at least along the optical axis. Consequently, the first filter structure and the first surface of the backside substrate can form the first surface of the backside structure. In other words, a filter material can be arranged and structured only on the backside substrate on a surface around, for example laterally around, the optical axis. Consequently, the first filter structure can only partially form the first surface of the backside structure.

[0059] Furthermore, it should be generally noted that the cavity 210 may be formed at least partially by one of the following: a recess in the second layer, a recess in the second further layer, a recess in the third layer, a recess in the backside structure, a through-hole in the backside structure, and / or a through-hole in a compensation structure of the backside structure. A recess and / or a through-hole may be formed by at least one of the following: etching, powder blasting, and / or laser-induced deep etching (LIDE). Consequently, the cavity may be provided based on the formation of spacer structures using a respective mold structure to provide a cavity for a respective lens structure, and / or based on a recess or a through-hole in the backside structure.It should be noted that the cavity can be provided using one of the aforementioned techniques or both. Consequently, a respective lens structure can find space in the recess or through-hole in the backside structure, e.g., if the respective layer does not have a recess in which the lens structure is arranged.

[0060] Furthermore, it should be noted that a through-hole in the backside structure may be a through-hole through a component of the backside structure, such as the compensation structure. Consequently, the through-hole may be "closed" with a subsequent filter on one side, forming a cavity or a portion of a cavity. Additionally, a cavity may be understood as a "closed" cavity, where an internal volume of the cavity is completely sealed from the environment, as well as an "open" cavity, such as a natural cavity with an access, or in other words, a cavity that is not completely closed to the environment.

[0061] Optionally, the compensation structure 206 can be a generic compensation structure configured to compensate for manufacturing tolerances and / or to adjust or improve a focal point of a plurality of projection optics on average. In a batch manufacturing process of a plurality of projection optics, measurement results of the plurality of projection optics can be obtained to obtain suitable dimensions for the compensation structure 206. If, for example, different projection optics are similar, for example with regard to their tolerances, generic compensation structures can be formed and can be used equally for all projection optics. Thus, the compensation structures can be configured to compensate for the manufacturing tolerances (at least partially or approximately) and / or to adjust or improve the focal points of the plurality of projection optics, at least on average.In other words, the compensation structures can be formed as, in simple terms, a compromise to best improve the majority of projection optics.

[0062] Consequently, the compensation structures 206 can also be individual compensation structures configured to compensate for manufacturing tolerances and / or adjust or improve the focal point of the projection optics. Thus, for example, based on individual measurements of the respective projection optics, an individual compensation structure can be formed for each projection optic to best improve the characteristics of the respective optics.

[0063] Optionally, the projection optics 100a, 100b, and 100c can have a lateral size in the plane of the first layer 110 of at least 100 µm, or of at least 200 µm, or of at least 300 µm, or of at least 0.5 mm and of at most 2 mm, or of at most 3 mm, or of at most 5 mm. Alternatively or additionally, the projection optics can have a height, perpendicular to the first and second layers, of at least 0.5 mm, or of at least 1 mm, or of at least 2 mm and of at most 2 mm, or of at most 3 mm, or of at most 5 mm. Thus, as mentioned above, projection optics with small dimensions can be created. This can enable use for challenging applications, such as providing visual assistance for operations within the human body.

[0064] As another optional feature, the Fig. 1a-c, a sensor structure 220 connected to the compensation structure 206. Thus, using the compensation structure 206, rays passing through the projection optics can be precisely focused onto a sensor chip of the sensor structure 220.

[0065] The following refers to the Fig. 2a to t. Reference is made. Fig. Figure 2 shows schematic side views of an optical structure and components thereof and illustrates a method for manufacturing an optical structure according to embodiments of the invention. The manufactured optical structure can, for example, be the projection optics shown in Fig. 1 is shown.

[0066] The Fig. 2a-d show the formation of a first layer of the optical structure and the provision of a second layer of the optical structure. As in Fig. 1a, a first layer 310 may be formed, wherein forming the first layer comprises forming and curing a first curable material on a first mold structure 320 to form the first layer such that a first optical lens surface 312 is formed on a first side of the first layer where the first layer is adjacent to the first mold structure.

[0067] Optionally, as in Fig. 2b, a method according to embodiments may include providing one or more coating layers between the first layer 310 and a second layer. Therefore, as shown in Fig. 2b, a coating layer 330 may be disposed on a planar surface of the first layer 310 on the second side of the first layer 310. As a further optional feature, the one or more coating layers 330 may be structured. As an example, as shown in Fig. 2b, a coating layer 330 forms an aperture. However, it should be noted that in addition to an aperture, the one or more coating layers can optionally form a filter and / or a filter and an aperture.

[0068] It should be noted that the provision of the coating layer is performed on a second side, opposite the first side, of the first layer 310, wherein the first layer 310 is adjacent to the first mold structure 320 on the first side of the first layer.

[0069] As in Fig. 2c, a second layer of the optical structure may be provided on a second side, opposite the first side, of the first layer 310, again while the first layer 310 is adjacent to the first mold structure 320 on the first side of the first layer. As shown in Fig. 2c, a second mold structure 350 may be used for forming the second layer, but it should be noted that this feature is only optional.

[0070] Consequently, as in Fig. 2c, providing the second layer 340 may comprise forming and curing a second curable material on the second side of the first layer 310 using the second mold structure 350 to form the second layer, such that a second optical lens surface 344 is formed on a second side of the second layer 340, on which the second layer is adjacent to the second mold structure 350 and which faces away from the second side of the first layer 310, and such that the second optical lens surface 344 is aligned with the first optical lens surface 312 at an optical axis 360 of the optical structure. As shown in Fig. 2c, the second optical lens surface 344 may be a convex lens, but alternatively, as shown in Fig. 2d, a concave shape can also be provided. Thus, the mold structure 350 can have a different shape, as shown in Fig. 2d is shown.

[0071] As optionally shown, a respective mold structure may comprise a master carrier 322 or 354 and a master (PDMS) 324 or 352. The master carrier may, for example, comprise glass or be made of glass, and the master may comprise polydimethylsiloxane. In the example, as shown in the Fig. As shown in Figures 2a-t, the first layer 310 may be a first replication layer, and the second layer 330 may be a second replication layer. Replication layer 2 and replication layer 2a may thus be different examples of the second layer 330, differing in the shape of the respective optical lens surfaces 344.

[0072] In other words, referring to Fig. 2a, according to embodiments, a first process step may consist of replicating a lens layer 1, e.g., the replication layer 1, using the master 324 (e.g., a typical PDMS-type material) including a master carrier 322 (e.g., typical glass). The replication layer may be applied by a paddling process and may subsequently be UV-cured. As an example, such a paddling process may comprise applying an epoxy material, e.g., replication layer 1, to a substrate or wafer, or, according to preferred embodiments, to a mold structure, e.g., by a mechanical "paddle," to achieve a final thickness of the material. Furthermore, the paddling process may comprise removing the excess material with the paddle.

[0073] As another example, spin coating can be performed for the above process step.

[0074] Referring to Fig. 2b, as an example and in other words, at this process step, the replicated layer may still be held in the master 324, and a coating layer 330 may be applied in the shape of an aperture by coating a thin layer of, e.g., an opaque black material (which may be, e.g., lithographically patterned), e.g., by spin coating, which may be patterned by a lithographic process to create the coating layer in the shape of the apertures. It should be noted that, in contrast to conventional approaches in which the aperture is patterned on a glass substrate with typical black chrome, according to embodiments, the aperture opening may be patterned directly on the replication layer.

[0075] Referring to Fig. 2c, as an example and in other words, at this process step, the replication layer (containing the structured aperture) may still be held in the master, wherein then the replication layer 2 (lens 2, e.g., the layer 340 having the second optical lens surface 344) is replicated by using a second master 352 (containing the master carrier 354).

[0076] As in Fig. 2, a method according to the invention may be performed according to embodiments to provide a plurality of optical structures, for example, on a wafer level or in an array arrangement. Consequently, as shown, a plurality of optical lens surfaces 312 and 344 may be provided (see, for example, a later singulation step shown in Fig. 2q). Consequently, later in the process, the layers can be singulated to provide the majority of optical structures. In this regard, it should be noted that although lenses can be fabricated at the wafer level, no glass substrate can be used between replication layer 1 and replication layer 2, and replication layer 2 can be replicated directly onto the aperture and onto replication layer 1.

[0077] Referring to Fig. 2d can, in other words and as an example, Fig. 2d show an alternative approach, e.g., alternative to the approach described in Fig. 2c, in which the replication layer 2 is no longer a convex lens, but has a concave shape (replication layer 2a) to be able to produce an achromat. For example, the lens layer 2a (e.g., the second layer 340) may have a relatively low Abbe number (e.g., a V number or constringency of a transparent material) and may be a flint-type material.

[0078] With reference to the Fig. 2e and f, a third layer 370 of the optical structure can be provided as a further optional feature. As shown in Fig. 2e, providing the third layer 370 may include removing the second mold structure 350 from the second layer 340 and forming and curing a third curable material on the second side of the second layer 340 between the second layer and a third mold structure 350a (which in turn optionally includes a master 352a and a master carrier 354a), as shown in Fig. 2f is shown to form the third layer, so that the third layer is adjacent to the second layer 340 on a first side of the third layer 370 and on a second side of the third layer, which is facing away from the first side of the third layer and on which the third layer is adjacent to the third mold structure 350, a third optical lens surface 372, as in Fig. 2f, and such that the first optical lens surface 312 is aligned with the third optical lens surface 372 at the optical axis 360 of the optical structure.

[0079] As shown, the third layer 370 may optionally be provided while the first layer 310 is adjacent to the first mold structure 320 on the first side of the first layer.

[0080] In other words, referring to the Fig. 2e in this step the master 352, which forms the concave lens, for example the lens surface 344, which is Fig. 2d, but the entire wafer is still held in the master 324 by the lens 1.

[0081] It should be noted that the manufacturing steps of the Fig. 2e and Fig. 2f based on the approach as described in Fig. 2d. However, the provision of the third layer can also be used for an optical structure as shown in Fig. 2c, or any other alternative layer stack according to an embodiment of the invention.

[0082] Again, to put it in other words and as an example, to complete the alternative approach, such as in Fig. 2d, and to produce an achromat, another layer (replication layer 2b, e.g., having a double convex shape) may be overcoated on the replication layer 2a to produce the achromat. The lens layer 2b (e.g., the third layer 370) may, for example, have a relatively high Abbe number and may represent the Kron-type material that may be needed to produce an achromat and to improve chromatic aberrations. Thus, in summary, embodiments comprise producing an achromat on wafer-level optics, for example, especially compared to conventional approaches.

[0083] As another optional feature, the steps described in the Fig. 2a-d, to provide and form a first and a second further layer. Consequently, a further layer stack may be provided in a similar or identical manner, wherein forming the first further layer of the optical structure comprises forming and curing a first further curable material on a first further mold structure to form the first further layer, such that a first further optical lens surface is formed on a first side of the first further layer on which the first further layer is adjacent to the first further mold structure.Furthermore, providing the second further layer of the optical structure on a second side, opposite the first side of the first further layer, while the first further layer is adjacent to the first further mold structure on a first side of the first further layer, may comprise forming and curing a second further curable material on the second side of the first further layer using a second further mold structure to form the second further layer, such that a second further optical lens surface is formed on a second side of the second further layer on which the second further layer is adjacent to the second further mold structure and which faces away from the second side of the first further layer, and such that the second further optical lens surface is aligned with the first further optical lens surface on the optical axis of the optical structure.

[0084] Consequently, in simple terms, the steps described in the Fig. 2a-d, layer 310 may represent the first further layer. Layer 340 may represent the second further layer, wherein first mold structure 320 may represent the first further mold structure, and mold structure 350 may represent the second further mold structure.

[0085] It should be noted that, consequently, one or more further coating layers may be provided between the first further layer and the second further layer, and that at least one of the one or more further coating layers may be structured. In addition, as explained in connection with the one or more coating layers, the one or more further coating layers may thus form an aperture and / or a filter, or both simultaneously.

[0086] In this regard, it should be noted that a thickness of a coating layer of the one or more coating layers and / or the one or more further coating layers, between the first and the second layer and between the first and the second further layer, may each be at most 10% or at most 5% or at most 2% or at most 1% of the thickness of the first layer or the thickness of the second layer and / or the thickness of the first further layer and / or the thickness of the second further layer, respectively.

[0087] The second layer stack, which has the first and the second further layer, can thus be connected to the first layer stack, which has the first and the second layer. Therefore, as in Fig. 2e, the second mold structure 350 may be removed. Furthermore, the first further mold structure may be removed (not shown) for bonding. Then, the first further layer may be bonded (not shown) to the second layer 340 such that the first further layer is adjacent to the second layer on a second side of the second layer and on the first side of the first further layer, and such that the first further optical lens surface is aligned with the second optical lens surface 344 at the optical axis 360 of the optical structure. Consequently, as discussed in connection with Fig. 1c, the first further optical lens surface and the second optical lens surface are formed, so that the optical structure has a cavity between the first further optical lens surface and the second optical lens surface at the optical axis of the optical structure. Again, it should be noted that the further layer stack can also be connected to a third layer of the optical structure.

[0088] Fig. Fig. 2g shows a further optical process step according to embodiments, wherein, for example, as a next step for the structure as shown in Fig. 2c, the first and second mold structures 320 and 350 may be removed. In other words, a next process, e.g., in a case where the optical structure is not achromatic, may consist of removing the master wafer on both sides.

[0089] Fig. Figure 2h shows an example of a further optical process step, e.g., for the structure shown in Fig. 2f, which includes the removal of the first and third mold structures 320 and 350a. In other words, a next process step of the alternative approach (Achromat) may be to remove the master wafer on both sides.

[0090] However, it should be noted that the removal of individual mold structures can be performed one after the other. Fig. 2i and Fig. 2j show the additional optional method step of providing an optical substructure. The optical substructure 380 has a support structure 382 and an additional layer 384. Providing the optical substructure may include forming and curing an additional curable material between an additional mold structure 390 and the support structure 382 to form the additional layer 384, such that an additional optical lens surface 386 is formed on a second side of the additional layer 384, on which the additional layer adjoins the additional mold structure 390, and such that the additional layer adjoins the support structure 382 on a first side of the additional layer, which is opposite the second side of the additional layer.

[0091] Again, the additional mold structure 390 may optionally include a master 392 and a master support 394. Furthermore, as shown, the additional layer may be a replication layer, namely a replication layer 3, and in the same way, the support structure may be a replication base layer.

[0092] As in the example of Fig. 2i, the support structure may be a substrate. Alternatively, as shown in Fig. 2j, the support structure 382 is a mold structure and / or, as specifically shown in Fig. 2j, can be a mold structure with a planar topology. As a further optional feature, Fig. 2j the planar mold structure again has a master carrier 3801 and a master 3822.

[0093] Referring to Fig. 2i, as an example and in other words, in this process step, the lens replication layer 3 can be formed by replication directly on a glass substrate, e.g., in the form of the replication base layer, and using a master 392 (PDMS) and a master carrier 394.

[0094] Consequently, in other words and with reference to Fig. 2 years, Fig. 2j shows an alternative approach in which no substrate (front glass) is used to replicate the lens layer 3, e.g., the replication layer 3, but only a master support 3821 comprising a flat PDMS layer 3822. As an example, the lens layer, e.g., 384, can be replicated by using a master, e.g., 392, with a layer 3 structure and a master support, e.g., 394.

[0095] Afterwards, as an optional feature, both masters 382 and 390 can be removed, as shown in the Fig. 2g) and h). Consequently, embodiments may include optical structures without a cover glass in the finished product, but rather have a substrateless design.

[0096] As an optional feature in the Fig. 2k and Fig. 2l, at least after removing the first mold structure 320 from the first layer 310, such as in the Fig. 2g and Fig. 2h, and after removing the additional mold structure 390, the additional layer 384 is bonded to the first layer 310 such that the additional layer 384 is adjacent to the first layer 310 on the first side of the first layer and on a second side of the additional layer, and such that the additional optical lens surface 386 is aligned with a first optical lens surface 312 on the optical axis of the optical structure. As optionally shown in Fig. 2l, a method according to the invention may further comprise removing the support structure 382 from the additional layer 384. It should be noted that the removal of the support structure is independent of a shape of the structure, which is why the support structure may be removed in the form of a glass substrate or a substrate, or in the form of the mold structure, or even in the form of a planar mold structure, such as in Fig. 2j is shown.

[0097] As another optional feature, as in Fig. 2k, a method according to embodiments may include bonding a first surface of a backside structure 410 to the second layer 340 on a second side of the second layer such that the second optical lens surface 344 and the first surface of the backside structure form a cavity 450 (as shown in Fig. 2m). As shown in Fig. 2g, for connecting the backside structure 410, the method may include removing the second mold structure 350 from the second layer 340, for example, beforehand.

[0098] Consequently, as in Fig. 2l, in the case of an optical structure having a third layer 370, the third shape structure 380, as shown for example in Fig. 2h, and a first surface of the backside structure 410 may be bonded to the third layer 370 on a second side of the third layer such that the third optical lens surface 372 and the first surface of the backside structure form a cavity 450 (as shown in Fig. 2n is shown).

[0099] As optional in the Fig. 2k and Fig. As shown in Figure 2l, the backside structure 410 may include a substrate 412 and a filter 414. The filter may include a first filter structure 4141 disposed on a first surface of the backside substrate and a second filter structure 4142 disposed on a second surface opposite the first surface of the backside substrate.

[0100] In other words, referring to Fig. 2k, the backside substrate 412 may be a filter support or act as a filter support, and the layer 4141 may be a filter compensation or a filter compensation layer, and the layer 4142 may be a filter layer. As explained above, double-sided application of a filter layer may mitigate warping effects and may enable the provision of a flat backside structure 410 that can be precisely bonded to the respective layer 340 or 370. Furthermore, as an example and in other words, once the lens layers 1, 2, and 3 are completed, they may be stacked and bonded together, and then a backside glass, e.g., 410, may be bonded, which may, e.g., be just glass, wherein the thickness may, e.g., be well-defined with a low TTV (low total thickness variation).

[0101] Thus, embodiments according to the invention can generally also comprise backside structures that have only one backside substrate. The backside glass, for example 410, can have an integrated optical filter, e.g., 414, e.g., an NIR cut filter, a notch filter, a bandpass filter, etc. As previously explained, the filter can be applied to both sides to obtain no or only limited or low distortion on the filter substrate, so that compensation takes place and a substrate remains flat. Referring to Fig. 2l can be the same or similar process as in Fig. 2k, but now with the alternative approach of lens 1, 2a / b and lens 3 (achromat).

[0102] The results of the stacking steps as described in the Fig. 2k and Fig. 2l are shown in the Fig. 2m and Fig. 2n. As shown, optionally, the first optical lens surface 312 and the additional optical lens surface 386 may be formed such that the optical structure includes a cavity 420 between the first optical lens surface and the additional optical lens surface at the optical axis 360 of the optical structure.

[0103] As an example and in other words, Fig. 2m show a final connected stack still in wafer format, and Fig. 2n can show a final connected stack still in wafer format (alternative achromat approach).

[0104] The Fig. 2o and Fig. 2p show further optional features of a method according to embodiments, wherein the optical structure is provided with a compensation structure 430 or 4301, 4302, and 4303. The configuration structure can be configured to compensate for manufacturing tolerances and / or to adjust or improve a focal point of the optical structure. Additionally, the backside structure 410 can include the compensation structure.

[0105] Therefore, the respective compensation structure can be connected to the first and / or second filter structure. As previously explained, simply put, the order of the compensation structure and the substrate 412 and the filter 414 can be changed. Thus, as alternatives, a method according to the invention can optionally comprise connecting the first filter structure to the second surface of the compensation structure, such that the first surface of the compensation structure forms the first surface of the backside structure 410, such that the compensation structure is connected to the second or third layer or, for example, the second further layer. Alternatively, a method according to the invention can optionally comprise connecting the first surface of the compensation structure to the second filter structure 4142, such that the first filter structure 4141 forms the first surface of the backside structure 410, such as in the Fig. 2o and Fig. 2p is shown.

[0106] It should be noted, however, that the backside structure 410 may, for example, have only the compensation structure 430 or 4301 or only the elements 412 and 414.

[0107] How Fig. 2o, the compensation structure may be a generic compensation structure used for each of the optical structures of a set of optical structures. As shown in Fig. 2o, the compensation structure 430 can thus be, for example, a globally adjusted backglass. Optionally, the method can further comprise determining a plurality of sets of parameters, each set of parameters characterizing an optical structure of a plurality of optical structures, and providing the compensation structure as a generic compensation structure. Providing the compensation structure can further comprise adjusting the compensation structure based on the plurality of sets of determined parameters in order to compensate for manufacturing tolerances and to adjust or improve a focal point of the optical structures on average.

[0108] As in Fig. 2o and previously mentioned, a separation into a plurality of optical structures can be performed, here as an example for the sake of simplicity into three different optical structures I, II and III. It should be noted that in general, according to embodiments, a large number of structures, e.g., hundreds or thousands or tens of thousands of optical structures or projection optics or lens stacks can be arranged in a row, e.g., of a wafer or an array arrangement. In other words, the drawing may show only a section of three structures of what is typically more in reality (e.g., on an 8-inch wafer there could easily be 10,000 structures or perhaps 100) in a row.

[0109] Thus, measurements can be performed for each of these stacks and, for example, respective characteristics of the stacks that can be singulated into different optical structures can be similar enough (e.g., in terms of yield or behavior) to use the generic structure so that manufacturing tolerances are compensated on average (e.g., to allow for "trade-off compensation" for the three optical structures I, II, II).

[0110] If these layer stacks, which can be separated into the individual optical structures I, II, III, are not similar enough, or the approach of, for example, a globally adapted back glass would result in too many faulty devices based on respective measurements and / or sets of parameters characterizing a respective optical structure, consequently, as for example in Fig. 2p, individual compensation structures 4301, 4302 and 4303 are provided, wherein the respective individual compensation structures are adjusted based on a respective set of parameters in order to compensate for manufacturing tolerances and / or to adjust or improve a focal point of a respective optical structure.

[0111] In other words, and as an example, referring to Fig. 2o To compensate for tolerances and produce a camera with a well-defined optimal focus position, it may be necessary to add an additional glass spacer wafer (e.g., compensation structure 430). For example, all lenses on the stacked wafer or array assembly can be measured for MTF (Modulation Transfer Function), BFL (Back Focal Length), EFL (Effective Focal Length), etc., e.g., using an automated test system, and a wafer map or array map can be generated for the majority of optical structures.If the tolerances of sets of parameters, such as the BFL, within a wafer or array are not too large, the globally matched back glass approach can be used. This means, for example, that the average value of all lenses or layer stacks on a wafer or in an array of optical structures with respect to the BFL can be calculated, and the compensation structure, such as the back glass wafer, can be ground to this thickness. Lenses (such as layer stacks I, II, and / or III) that have a poor MTF, or where the BFL is too short, or even much too short, or too long, or even much too long, cannot or would not be used, and yield may or will decrease.

[0112] Consequently, with reference to Fig. Alternatively, custom spacers can be used if tolerances are too high when globally customized back glasses are used and the yield may be unacceptable. Again, all lenses of the stacked wafers can be measured with respect to characterizing parameters, e.g., MTF, BFL, EFL, etc., e.g., with an automated test system, and a wafer or array map can be generated. A set of already singulated compensation structures with predefined dimensions, e.g., glass substrates, e.g., 4301, 4302, 4303, can be prepared or will be prepared, which have different, e.g., well-defined, thicknesses (e.g., a plurality of, say, 5 different ones with specific differences), whereby these small glass substrates can then be bonded as individual pieces to the individual lens stacks. As an example, a shorter BFL may require a thinner back glass, etc.it is possible that typically only lenses with a poor MTF have to be rejected at the end.

[0113] Referring to the Fig. 2q and Fig. 2r, a method according to embodiments may optionally include performing a singulation to singulate the optical structures I, II, and III of the plurality of optical structures. In other words, and as an example, after everything is completed, the entire wafer or the entire array may be singulated, e.g., with a wafer saw using a blue tape or a UV stripping tape. Fig. Figure 2q shows an example using a globally adapted back glass 430, where Fig. 2r shows individually adapted back glasses for the alternative approach (achromat) as an example.

[0114] As in the Fig. 2s and Fig. 2t, a method according to the invention may optionally include connecting a sensor structure 440 to the optical structure. As shown, the sensor may include a cover glass. In other words, and as an example, once the optical stack is completed, a CMOS image sensor may be connected to the lens. Fig. 2t can show the alternative approach with the achromat.

[0115] The Fig. 1a) and Fig. 1b) the final results of a manufacturing process may be determined in accordance with Fig. 2a) to s) or t). Consequently, according to the embodiments described in connection with Fig. 2 were declared in the Fig. 1a) and b) the layer 110 may be the replication layer 1, the layer 120 may be the replication layer 2 (in Fig. 1a)) or the replication layer 2a (in Fig. 1b)), the layer 180 may be the replication base layer, the layer 160 may be the replication layer 3, the coating layer 140 may be the aperture, the layer 190 in Fig. 1b) may be a replication layer 2b, element 202 may be a filter support, element 2041 is a filter compensation and element 2042 is a filter layer, element 206 is a matched spacer, and element 220 is a sensor with a cover glass.

[0116] Thus, Fig. 1a) show a final product with three aspherical surfaces and one aperture, where there is no substrate between layer 1 and layer 2 and where there is a substrate on the replication layer 3 (which can also act as a coverslip). Fig. 1b) can show a final product with four aspherical surfaces (where 2a and 2b act, for example, as an achromat) and one aperture, with no substrate between layers 1 and 2a / b and no substrate on the replication layer 3.

[0117] In general, it should be noted that embodiments according to the invention may include aspherical and / or spherical optical lens surfaces. In other words, and as an example, all lens surfaces, such as those shown, may typically have an aspherical shape, but could also be spherical depending on the specific design. Furthermore, as previously explained, a process according to embodiments may be in a wafer format, e.g., round 6-inch, 8-inch, or 12-inch substrates, but square or rectangular substrates are also possible. As an example, a typical size of a final product may be approximately 1 mm x 1 mm with a height of 2 mm and a pitch between lenses of, for example, 1.4 mm.

[0118] Fig. 3 shows schematic views of another projection optics according to embodiments of the invention. Fig. Figure 3 shows a schematic top view 510 of a plurality of projection optics I, II, and III in a wafer-level or array-level arrangement. As an example, respective projection optics can be separated along the dashed lines 512, 514.

[0119] Furthermore, Fig. 3 shows a schematic side view 520 along a section plane AA, as shown in the schematic top view 510. As explained above, the projection optics 500 (III) comprises a first layer 522 of a first cured material, for example in the form of a replication layer (replication layer 2), which has a first optical lens surface 524 on a first side of the first layer at an optical axis 526 of the projection optics and a planar portion 528 on a second side of the first layer, opposite the first side of the first layer, at the optical axis.The projection optics 500 (III) further comprises a second layer 530 of a second cured material in the form of another replication layer (replication layer 3) having a planar portion 532 on a first side of the second layer at the optical axis 526 and a second optical lens surface 534 on a second side of the second layer opposite the first side of the second layer at the optical axis 526.

[0120] As an optional feature, the projection optics 500 includes an additional layer 536 of an additional cured material adjacent to the first layer 522 on the first side of the first layer and on a second side of the additional layer. The additional layer further includes an additional optical lens surface 538 on the second side of the additional layer at the optical axis 526 of the projection optics, and a cavity 540 between the first optical lens surface 524 and the additional optical lens 538 at the optical axis.

[0121] Furthermore, as a further optional feature, the projection optics comprises a support structure 542 which adjoins the additional layer on a first side, opposite the second side, of the additional layer, wherein the support structure is a substrate in the form of a front glass.

[0122] Furthermore, the projection optics 500 has a lithographically structured coating layer 544 (e.g., made of a polymer material) in the form of an aperture.

[0123] As a further optional feature, the projection optics 500 includes a backside structure 546 and a cavity 548, wherein a first surface of the backside structure is adjacent to the second layer 530 on the second side of the second layer, and the cavity 548 is disposed between the backside structure 546 and the second optical lens surface 534 at the optical axis 526.

[0124] As an example, the backside structure 546 includes a backside substrate with a filter 550 in the form of a back glass and a compensation structure 552 in the form of a spacer glass for spacer adjustment. As previously explained, the compensation structure is configured to compensate for manufacturing tolerances and / or adjust or improve a focal point of the optical structure.

[0125] The filter comprises a first filter structure disposed on a first surface of the backside substrate and a second filter structure disposed on a second surface of the backside substrate opposite the first surface. The compensation structure comprises a first surface and a second surface, the second surface being opposite the first surface.

[0126] In the example shown in Fig. 3, the first filter structure adjoins the second surface of the compensation structure such that the first surface of the compensation structure forms the first surface of the backside structure.

[0127] Fig. 3 further shows an enlarged schematic side view 560 of a section B as shown in view 520, highlighting the layer structure. In addition, Fig. 3 is an enlarged schematic side view 570 of a portion C as shown in view 560, further highlighting the thin, structured coating layer 544 between the first and second layers.

[0128] Furthermore, embodiments according to the invention comprise miniaturized wafer-level cameras.

[0129] Embodiments according to the invention include miniaturized wafer-level cameras with a wide field of view, which cover a first glass substrate (e.g. 180 ( Fig. 1); e.g. 540 ( Fig. 3)), which is in the direction of the object, followed by a replicated epoxy layer (e.g. layer 160 ( Fig. 1); e.g. layer 382 ( Fig. 2); e.g. layer 536 ( Fig. 3)) with a first lens (e.g. 162 ( Fig. 1); e.g. 386 ( Fig. 2); e.g. 538 ( Fig. 3)) with a concave aspherical surface facing the sensor side. This epoxy layer may also have, for example, integrated posts / spacers around the lens so that the next layer can be stacked on top. As an example of a corresponding mold structure, an additional mold structure may, for example, have posts / spacers to form a cavity (e.g., 150 ( Fig. 1), e.g., 420 ( Fig. 2), e.g. 540 ( Fig. 3)) between lens surfaces. The first lens is followed by a replicated second lens (e.g. layer 110 ( Fig. 1); e.g. layer 310 ( Fig. 2); e.g. layer 522 ( Fig. 3)) which has a convex aspherical surface (e.g. 112 ( Fig. 1); e.g. 312 ( Fig. 2); e.g. 524 ( Fig. 3)) and epoxy or, for example, consists only of epoxy. As soon as this second lens wafer (e.g. layer 110 ( Fig. 1); e.g. layer 310 ( Fig. 2); e.g. layer 522 ( Fig. 3)) is replicated, a black material can or will optionally be structured on the flat surface, generally a coating layer (e.g. 140 ( Fig. 1); e.g. 330 ( Fig. 2); e.g. 544 ( Fig. 3)), which can optionally be structured by a photolithographic process to form an aperture. As a next step, the third lens (e.g. layer 120 ( Fig. 1); e.g. layer 340 ( Fig. 2); e.g. layer 530 ( Fig. 3)), which has a different convex aspherical lens structure (e.g. 124 ( Fig. 1); e.g. 344 ( Fig. 2); e.g. 534 ( Fig. 3)). Both replicated convex surface layers can, for example, also have integrated posts so that the wafers can be connected to each other (e.g. such that respective cavities (150 and 210 ( Fig. 1); 420 and 450 ( Fig. 2); 540 and 450 ( Fig. 3)) are formed).

[0130] Another way of optimizing the behavior of the lens design (and / or to provide an alternative lens design) may be to split lens 3 into two, which means creating an achromat by first replicating a lens 3a (as for example with the replication layer 2a in Fig. 2) which has a concave surface and whose lens material has a refractive index of, for example, at least 1.5 and at most 2.0, for example 1.6, and a low Abbe number of, for example, less than 50, for example 28 (Flint), and then a convex layer is formed thereover, which is the lens 3b (as, for example, with replication layer 2b in Fig. 2) of a lens material having a refractive index of, for example, 1.52 or less and an Abbe number of, for example, more than 50, for example 52 (Kron).

[0131] If the third lens already has the posts / spacers integrated (e.g. to create a cavity, e.g. 210 in Fig. 1c), another substrate (e.g. 202 in Fig. 1, e.g., 412 in Fig. 2), e.g., a glass substrate (e.g., a second glass substrate). This second glass substrate can also be a wavelength filter (e.g., 204 in Fig. 1, e.g., 414 in Fig. 2), such as an NIR cut filter. One option is to arrange the filter layers on both sides of the second glass substrate, for example, to compensate for stresses and / or thermal mismatch and to minimize wafer warping. Another option is to apply the filter to the second glass wafer only on the side facing the object, but not over the entire wafer surface, for example, but structured and only in the areas where it is optically required.

[0132] Another option is for the glass substrate 2 to have or consist of an etched cavity toward the third lens. In this case, the replicated third lens layer does not need to have the posts / spacers integrated, or may not need to have them integrated, for example, because the lens finds space in the cavity of the glass. However, both sides (third lens layer and etched cavity in the glass) can optionally be integrated and act as spacers.

[0133] Another way to create the spacers is to use a glass spacer that has integrated through-holes, where these through-holes can be produced, for example, by etching, powder blasting and / or by LIDE (laser-induced deep etching).

[0134] Spacers can also be manufactured by replicating a spacer structure on top of a glass substrate.

[0135] Once the entire optical stack is interconnected, an image sensor can be attached. The image sensor can have or include a cover glass that can be bonded directly to the image sensor surface. Since the image sensor may require microlenses per pixel for fill factor improvement and crosstalk minimization, a transparent material with a low refractive index (low-n material) can be or is coated before the cover glass is applied to the sensor at the wafer level, so that even when these microlenses are completely covered with material, they are still optically functional. The cover glass can be glued over the low-n material, which can then be bonded to the optical stack.

[0136] Although some aspects have been described in connection with a device, it is clear that these aspects also represent a description of the corresponding method, with a block or device corresponding to a method step or a feature of a method step. Similarly, aspects described in connection with a method step also represent a description of a corresponding block, article, or feature of a corresponding device.

[0137] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to those skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the appended claims and not by the specific details presented to describe and explain the embodiments herein.

Claims

[1] Projection optics (100a-c, 500) with the following features: a first layer (110, 310, 522) of a first cured material, wherein the first layer has a first optical lens surface (112, 312, 524) on a first side of the first layer at an optical axis (130, 360, 526) of the projection optics, and wherein the first layer has a planar portion (114, 528) on a second side of the first layer, opposite the first side of the first layer, at the optical axis; and a second layer (120, 340, 530) of a second cured material, wherein the second layer has a planar portion (122, 532) on a first side of the second layer at the optical axis (130, 360, 526), ​​and wherein the second layer has a second optical lens surface (124, 344, 534) on a second side of the second layer, opposite the first side of the second layer, at the optical axis; wherein the planar portion (114, 528) of the first layer is adjacent to the planar portion (122, 532) of the second layer at the optical axis, or wherein the planar portion (114, 528) of the first layer is separated from the planar portion (122, 532) of the second layer at the optical axis only by one or more coating layers (140, 330, 544); and wherein the projection optics has a lateral size in a plane of the first layer (110, 310, 522) of at least 100 µm or of at least 200 µm or of at least 300 µm or of at least 0.5 mm and of at most 2 mm or of at most 3 mm or of at most 5 mm; and / or wherein the projection optics has a height perpendicular to the first and second layers (120, 340, 530) of at least 0.5 mm or of at least 1 mm or of at least 2 mm and of at most 2 mm or of at most 3 mm or of at most 5 mm. [2] Projection optics (100a-c, 500) according to claim 1, further comprising the following features: a first further layer (110c) made of a first further cured material, wherein the first further layer has a first further optical lens surface (112c) on a first side of the first further layer at the optical axis (130, 360, 526) of the projection optics, and wherein the first further layer has a planar portion (114c) on a second side of the first further layer, opposite the first side of the first further layer, at the optical axis; and a second further layer (120c) of a second further cured material, wherein the second further layer has a planar portion (122c) on a first side of the second further layer at the optical axis, and wherein the second further layer has a second further optical lens surface (124c) on a second side of the second further layer, opposite the first side of the second further layer, at the optical axis (130, 360, 526); wherein the planar portion (114c) of the first further layer is adjacent to the planar portion (122c) of the second further layer at the optical axis; or wherein the planar portion of the first further layer is separated from the planar portion of the second further layer at the optical axis only by one or more further coating layers (140c); and wherein the first further layer is adjacent to the second layer (120, 340, 530) at the second side of the second layer and at a first side of the first further layer. [3] Projection optics (100a-c, 500) according to claim 1 or 2, wherein the one or more coating layers (140, 330, 544) comprise a structured coating layer; and / or wherein the one or more further coating layers (140c) comprise a structured coating layer. [4] Projection optics (100a-c, 500) according to any one of the preceding claims, wherein at least one of the one or more coating layers (140, 330, 544) and / or the one or more further coating layers (140c) forms an aperture of the projection optics; and / or wherein at least one of the one or more coating layers and / or the one or more further coating layers forms a filter of the projection optics; and / or wherein at least one of the one or more coating layers and / or the one or more further coating layers forms an aperture and a filter of the projection optics. [5] Projection optics according to any one of claims 2 to 4, wherein the projection optics further comprises the following feature: a cavity (150c) between the second optical lens surface (124, 344, 534) and the first further optical lens surface at the optical axis (130, 360, 526). [6] Projection optics (100a-c, 500) according to any one of the preceding claims, wherein the projection optics further comprises the following features: an additional layer (160, 384, 536) of an additional cured material adjacent to the first layer (110, 310, 522) on the first side of the first layer and on a second side of the additional layer; wherein the additional layer has an additional optical lens surface (162, 386, 538) on the second side of the additional layer at the optical axis (130, 360, 526) of the projection optics. [7] Projection optics (100a-c, 500) according to claim 6, further comprising the following feature: a cavity (150, 420, 540) between the first optical lens surface (112, 312, 524) and the additional optical lens surface (162, 386, 538) at the optical axis (130, 360, 526). [8] Projection optics (100a-c, 500) according to claim 6 or 7, further comprising the following features: Alignment structures (170) disposed on the first side of the first layer (110, 310, 522) and on the second side of the additional layer (160, 384, 536), the alignment structures configured to align the first layer and the additional layer such that the first optical lens surface (112, 312, 524) is aligned with the additional optical lens surface (162, 386, 538) at the optical axis (130, 360, 526). [9] Projection optics (100a-c, 500) according to one of claims 6 to 8, wherein the projection optics comprises a support structure (180, 382, ​​3821, 3822) which adjoins the additional layer (160, 384, 536) on a first side, opposite the second side, of the additional layer. [10] Projection optics (100a-c, 500) according to claim 9, wherein the support structure (180, 382) is a substrate; or wherein the support structure (180, 382) is a molded structure; and / or wherein the support structure (180, 382) is a mold structure (3821, 3822) with a planar topology. [11] Projection optics (100a-c, 500) according to any one of the preceding claims, further comprising the following features: a third layer (190, 370) of a third cured material, wherein the third layer is adjacent to the second layer (120, 340, 530) on the second side of the second layer and on a first side of the third layer, or wherein the third layer (190, 370) is adjacent to the second further layer on the second side of the second further layer and on a first side of the third layer; and wherein the third step comprises a third optical lens surface (192, 372) on a second side, opposite the first side, of the third layer at the optical axis (130, 360, 526) of the projection optics. [12] Projection optics (100a-c, 500) according to any one of the preceding claims, wherein the projection optics further comprises the following features: a backside structure (200, 410, 546) and a cavity (210, 540, 548); wherein a first surface of the backside structure on the second side of the second layer is adjacent to the second layer (120, 340, 530) and wherein the cavity (210, 540, 548) is arranged between the backside structure and the second optical lens surface (124, 344, 534) on the optical axis (130, 360, 526), ​​or wherein a first surface of the backside structure adjoins the second further layer (120c) on the second side of the second further layer, and wherein the cavity (210, 540, 548) is arranged between the backside structure and the second further optical lens surface (124c) on the optical axis, or wherein a first surface of the backside structure on the second side of the third layer is adjacent to the third layer (190, 370), and wherein the cavity (210, 540, 548) is arranged between the backside structure and the third optical lens surface (192, 372) on the optical axis. [13] Projection optics (100a-c, 500) according to claim 12, wherein the backside structure (200, 410, 546) comprises a backside substrate (202, 412) and a filter (204, 414); wherein the filter comprises a first filter structure (2041, 4141) arranged on a first surface of the backside substrate, wherein the first filter structure forms the first surface of the backside structure; and wherein the filter comprises a second filter structure (2042, 4142) arranged on a second surface, opposite the first surface, of the backside substrate, or wherein the filter has a first filter structure (2041, 4141) arranged on a first surface of the backside substrate at least on the optical axis, and wherein the first filter structure and the first surface of the backside substrate form the first surface of the backside structure. [14] Projection optics (100a-c, 500) according to claim 12, wherein the backside structure (200, 410, 546) is a compensation structure (206, 430, 4301, 4302, 4303) configured to compensate for manufacturing tolerances and / or to adjust or improve a focal point of the projection optics. [15] Projection optics (100a-c, 500) according to claim 12, wherein the backside structure (200, 410, 546) comprises a backside substrate (202, 412), a filter (204, 414) and a compensation structure (206, 430, 4301, 4302, 4303), wherein the compensation structure is configured to compensate for manufacturing tolerances and / or to adjust or improve a focal point of the projection optics, wherein the filter comprises a first filter structure (2041, 4141) arranged on a first surface of the backside substrate; wherein the filter comprises a second filter structure (2042, 4142) arranged on a second surface, opposite the first surface, of the backside substrate, or wherein the filter has a first filter structure arranged on a first surface of the backside substrate at least on the optical axis, and wherein the first filter structure and the first surface of the backside substrate form the first surface of the backside structure; wherein the compensation structure has a first surface and a second surface, wherein the second surface is opposite the first surface; and wherein the first filter structure and / or the first surface of the backside structure adjoin the second surface of the compensation structure, such that the first surface of the compensation structure forms the first surface of the backside structure, or wherein the first surface of the compensation structure adjoins the second filter structure or the second surface of the backside substrate, such that the first filter structure and / or the first surface of the backside substrate form the first surface of the backside structure. [16] Projection optics (100a-c, 500) according to one of claims 14 to 15, wherein the compensation structure is a generic compensation structure (206, 430) configured to compensate for manufacturing tolerances and / or to adjust or improve a focal point of a plurality of projection optics on average. [17] Projection optics (100a-c, 500) according to one of claims 14 to 15, wherein the compensation structure is an individual compensation structure (4301, 4302, 4303) configured to compensate for manufacturing tolerances and / or to adjust or improve a focal point of the projection optics. [18] Projection optics (100a-c, 500) according to one of the preceding claims, in which at least two consecutive layers of the projection optics have different optical characteristics, and wherein an optical lens surface of a first of the two consecutive layers has a high refractive index and a low dispersion, and wherein an optical lens surface of a second of the two consecutive layers facing the optical lens surface of the first of the two consecutive layers has a low refractive index and a low dispersion to form an achromat. [19] Method for producing an optical structure (100a-c, 500), the method having the following features: Forming a first layer (110, 310, 522) of the optical structure, wherein the formation of the first layer has the following features Forming and curing a first curable material on a first mold structure (320) to form the first layer such that a first optical lens surface (112, 312, 524) is formed on a first side of the first layer where the first layer is adjacent to the first mold structure; and Providing a second layer (120, 340, 530) of the optical structure on a second side, opposite the first side, of the first layer, while the first layer is adjacent to the first mold structure on the first side of the first layer wherein the provision of the second layer (120, 340, 530) has the following features: Forming and curing a second curable material on the second side of the first layer (110, 310, 522) using a second mold structure (350) to form the second layer, such that a second optical lens surface (124, 344, 534) is formed on a second side of the second layer, on which the second layer is adjacent to the second mold structure and which faces away from the second side of the first layer; and such that the second optical lens surface is aligned with the first optical lens surface (112, 312, 524) at the optical axis (130, 360, 526) of the optical structure (100a-c, 500); and Removing the first mold structure (320) from the first layer (110, 310, 522); and Providing an optical substructure (380), wherein the optical substructure comprises a support structure (180, 382, ​​3821, 3822) and an additional layer (160, 384, 536) of the optical structure (100a-c, 500); and wherein the provision of the optical substructure has the following features Forming and curing an additional curable material between an additional mold structure (390) and the support structure (180, 382, ​​3821, 3822) to form the additional layer of the optical substructure, such that an additional optical lens surface (162, 386, 538) is formed on a second side of the additional layer on which the additional layer adjoins the additional mold structure, and such that the additional layer is adjacent to the support structure on a first side of the additional layer opposite the second side of the additional layer; Removing the additional mold structure; and Connecting the additional layer (160, 384, 536) to the first layer (110, 310, 522), so that the additional layer is adjacent to the first layer on the first side of the first layer and on the second side of the additional layer, and such that the additional optical lens surface (162, 386, 538) is aligned with the first optical lens surface (112, 312, 524) at an optical axis (130, 360, 526) of the optical structure (100a-c, 500). [20] A method according to claim 19, wherein the method further comprises: Forming a first further layer of the optical structure (100a-c, 500), wherein the formation of the first further layer has the following features Forming and curing a first further curable material on a first further mold structure to form the first further layer, such that a first further optical lens surface is formed on a first side of the first further layer on which the first further layer is adjacent to the first further mold structure; and Providing a second further layer of the optical structure (100a-c, 500) on a second side, opposite the first side, of the first further layer, while the first further layer is adjacent to the first further mold structure on the first side of the first further layer; wherein the provision of the second further layer has the following features Forming and curing a second further curable material on the second side of the first further layer, using a second further mold structure to form the second further layer, such that on a second side of the second further layer, on which the second further layer adjoins the second further shaped structure and which faces away from the second side of the first further layer, a second further optical lens surface is formed; and such that the second further optical lens surface is aligned with the first further optical lens surface at the optical axis (130, 360, 526) of the optical structure; and Removing the first additional mold structure; and Removing the second further mold structure (350); and Connecting the first further layer to the second layer (120, 340, 530), so that the first further layer is adjacent to the second layer on the second side of the second layer and on the first side of the first further layer, and such that the first further optical lens surface is aligned with the second optical lens surface (124, 344, 534) on the optical axis of the optical structure (100a-c, 500). [21] The method of claim 20, wherein the first further optical lens surface and the second optical lens surface (124, 344, 534) are formed such that the optical structure (100a-c, 500) has a cavity (150c) between the first further optical lens surface and the second optical lens surface at the optical axis (130, 360, 526) of the optical structure. [22] Method according to one of claims 19 to 21, further comprising the following features: Providing one or more coating layers (140, 330, 544) between the first and second layers (120, 340, 530); and / or providing one or more coating layers (140c) between the first further layer and the second further layer. [23] A method according to claim 22, further comprising: Structuring at least one of the one or more coating layers (140, 330, 544) and / or the one or more further coating layers (140c). [24] Method according to one of claims 22 or 23, wherein a thickness of a coating layer of the one or more coating layers (140, 330, 544) and / or the one or more further coating layers (140c) between the first and the second layer and / or between the first and the second further layer is in each case at most 10% or at most 5% or at most 2% or at most 1% of the thickness of the first layer (110, 310, 522) or the thickness of the second layer (120, 340, 530) and / or the thickness of the first further layer or the thickness of the further second layer. [25] Method according to one of claims 22 to 24, in which at least one of the one or more coating layers (140, 330, 544) and / or the one or more further coating layers (140c) forms an aperture of the projection optics; and / or in which at least one of the one or more coating layers and / or the one or more further coating layers forms a filter of the projection optics; and / or in which at least one of the one or more coating layers and / or the one or more further coating layers forms an aperture and a filter of the projection optics. [26] The method of any one of claims 19 to 25, wherein the method further comprises removing the support structure (180, 382, ​​3821, 3822) from the additional layer (160, 384, 536). [27] Method according to one of claims 19 to 26, wherein the support structure (180, 382) is a substrate; or wherein the support structure (180, 382) is a molded structure; and / or wherein the support structure (180, 382) is a mold structure (3821, 3822) with a planar topology. [28] Method according to one of claims 19 to 27, wherein the first optical lens surface (112, 312, 524) and the additional optical lens surface (162, 386, 538) are formed such that the optical structure (100a-c, 500) has a cavity (150, 420, 540) between the first optical lens surface and the additional optical lens surface at the optical axis (130, 360, 526) of the optical structure. [29] Method according to one of claims 19 to 28, further comprising the following features: Removing the second mold structure (350) from the second layer (120, 340, 530) and bonding a first surface of a backside structure (200, 410, 546) to the second layer on the second side of the second layer such that the second optical lens surface (124, 344, 534) and the first surface of the backside structure form a cavity (210, 540, 548) at the optical axis; or Removing the second further mold structure from the second further layer and connecting a first surface of the backside structure (200, 410, 546) to the second further layer on the second side of the second further layer such that the second further optical lens surface (124, 344, 534) and the first surface of the backside structure form a cavity (210, 540, 548) at the optical axis. [30] Method according to one of claims 19 to 29, further comprising the following features: Providing a third layer (190, 370) of the optical structure (100a-c, 500) on the second side of the second layer (120, 340, 530), wherein the provision of the third layer has the following features: Removing the second mold structure (350) from the second layer, and Forming and curing a third curable material on the second side of the second layer between the second layer and a third mold structure (350a) to form the third layer, such that, on a first side of the third layer, the third layer is adjacent to the second layer, and on a second side of the third layer facing away from the first side of the third layer and on which the third layer is adjacent to the third mold structure, a third optical lens surface (192, 372) is formed, and such that the first optical lens surface (112, 312, 524) is aligned with the third optical lens surface at the optical axis (130, 360, 526) of the optical structure; or Providing a third layer (190, 370) of the optical structure (100a-c, 500) on the second side of the second further layer, wherein the provision of the third layer has the following features: Removing the second further mold structure from the second layer; and Forming and curing a third curable material on the second side of the second further layer between the second further layer and a third mold structure (350a) to form the third layer, such that, on a first side of the third layer, the third layer adjoins the second further layer, and on a second side of the third layer, which is remote from the first side of the third layer and on which the third layer adjoins the third mold structure, a third optical lens surface (192, 372) is formed, and such that the first optical lens surface (112, 312, 524) is aligned with the third optical lens surface at the optical axis (130, 360, 526) of the optical structure. [31] The method of claim 30, wherein the third layer (190, 370) is provided while the first layer (110, 310, 522) is adjacent to the first mold structure (320) on the first side of the first layer. [32] A method according to claim 30 or 31, further comprising: Removing the third mold structure (350a) from the third layer (190, 370); and Bonding a first surface of a backside structure (200, 410, 546) to the third layer on the second side of the third layer such that the third optical lens surface (192, 372) and the first surface of the backside structure form a cavity (210, 540, 548). [33] A method according to claim 29 or 32, wherein the cavity is at least partially formed by at least one element of the following: a recess in the second layer, a recess in the second further layer, a recess in the third layer, a recess in the back structure, a through-hole in the backside structure, and / or a through-hole in a compensation structure of the backside structure. [34] Method according to claim 33, wherein a recess and / or a through-hole is produced by at least one of the following methods: etching, powder blasting and / or laser-induced deep etching, LIDE. [35] Method according to one of claims 29 or 32 to 34, in which the backside structure (200, 410, 546) comprises a backside substrate (202, 412) and a filter (204, 414), wherein the filter comprises a first filter structure (2041, 4141) arranged on a first surface of the backside substrate, wherein the first filter structure forms the first surface of the backside structure; and wherein the filter comprises a second filter structure (2042, 4142) arranged on a second surface, opposite the first surface, of the backside substrate, or wherein the filter has a first filter structure (2041, 4141) arranged on a first surface of the backside substrate at least on the optical axis, and wherein the first filter structure and the first surface of the backside substrate form the first surface of the backside structure. [36] Method according to one of claims 29 or 32 to 34, wherein the backside structure (200, 410, 546) is a compensation structure (206, 430, 4301, 4302, 4303) configured to compensate for manufacturing tolerances and / or to adjust or improve a focal point of the optical structure (100a-c, 500). [37] Method according to one of claims 29 or 32 to 34, in which the backside structure (200, 410, 546) comprises a backside substrate (220, 410), a filter (204, 414) and a compensation structure (206, 430, 4301, 4302, 4303), wherein the compensation structure is configured to compensate for manufacturing tolerances and / or to adjust or improve a focal point of the optical structure (100a-c, 500), wherein the filter comprises a first filter structure (2041, 4141) arranged on a first surface of the backside substrate, wherein the filter comprises a second filter structure (2042, 4142) arranged on a second surface, opposite the first surface, of the backside substrate, or wherein the filter has a first filter structure arranged on a first surface of the backside substrate at least on the optical axis, and wherein the first filter structure and the first surface of the backside substrate form the first surface of the backside structure; wherein the compensation structure has a first surface and a second surface, wherein the second surface is opposite the first surface; and wherein the method further comprises the following features: Connecting the first filter structure and / or the first surface of the backside substrate to the second surface of the compensation structure, so that the first surface of the compensation structure forms the first surface of the backside structure, or Connecting the first surface of the compensation structure to the second filter structure or to the second side of the backside substrate, such that the first filter structure and / or the first surface of the backside substrate form the first surface of the backside structure. [38] Method according to one of claims 19 to 37, wherein the method is performed on a wafer level to provide a plurality of optical structures (100a-c, 500) and / or wherein the method is carried out to obtain a plurality of optical structures (100a-c, 500) in an array arrangement. [39] Method according to one of claims 26 or 37, wherein the method is performed on a wafer level to provide a plurality of optical structures (100a-c, 500) and / or wherein the method for obtaining a plurality of optical structures (100a-c, 500) is carried out in an array arrangement, and the method further comprising the following features: Determining a plurality of sets of parameters, each set of parameters characterizing an optical structure of the plurality of optical structures; and Providing the compensation structure as a generic compensation structure (206, 430) used for each of the optical structures of the set of optical structures; wherein providing the compensation structure comprises adjusting the compensation structure based on the plurality of sets of determined parameters to compensate for manufacturing tolerances and / or to adjust or improve a focal point of the set of optical structures on average. [40] Method according to one of claims 36 or 37, wherein the method is performed on a wafer level to provide a plurality of optical structures (100a-c, 500) and / or wherein the method for obtaining a plurality of optical structures (100a-c, 500) is carried out in an array arrangement, and the method further comprising the following features: Determining a plurality of sets of parameters, each set of parameters characterizing an optical structure of the plurality of optical structures; Providing individual compensation structures (4301, 4302, 4303) for each of the optical structures of the set of optical structures; and Adjusting respective individual compensation structures based on a respective set of parameters to compensate for manufacturing tolerances and / or to adjust or improve a focal point of a respective optical structure. [41] Method according to one of claims 19 to 40, wherein the method is performed on a wafer level to provide a plurality of optical structures (100a-c, 500) and / or wherein the method for obtaining a plurality of optical structures (100a-c, 500) is carried out in an array arrangement, and the method further comprising the following feature: Performing singulation to separate optical structures of the plurality of optical structures. [42] A method according to any one of claims 19 to 41, wherein the method further comprises: Connecting a sensor structure (220, 440) to the optical structure (100a-c, 500). [43] Projection optics (100a-c, 500) with the following features: a first layer (110, 310, 522) of a first cured material, wherein the first layer has a first optical lens surface (112, 312, 524) on a first side of the first layer at an optical axis (130, 360, 526) of the projection optics, and wherein the first layer has a planar portion (114, 528) on a second side of the first layer, opposite the first side of the first layer, at the optical axis; and a second layer (120, 340, 530) of a second cured material, wherein the second layer has a planar portion (122, 532) on a first side of the second layer at the optical axis (130, 360, 526), ​​and wherein the second layer has a second optical lens surface (124, 344, 534) on a second side of the second layer, opposite the first side of the second layer, at the optical axis; wherein the planar portion (114, 528) of the first layer is adjacent to the planar portion (122, 532) of the second layer at the optical axis, or wherein the planar portion (114, 528) of the first layer is separated from the planar portion (122, 532) of the second layer at the optical axis only by one or more coating layers (140, 330, 544); and wherein the projection optics further comprises the following features: an additional layer (160, 384, 536) of an additional cured material adjacent to the first layer (110, 310, 522) on the first side of the first layer and on a second side of the additional layer; wherein the additional layer has an additional optical lens surface (162, 386, 538) on the second side of the additional layer at the optical axis (130, 360, 526) of the projection optics. [44] Projection optics (100a-c, 500) with the following features: a first layer (110, 310, 522) of a first cured material, wherein the first layer has a first optical lens surface (112, 312, 524) on a first side of the first layer at an optical axis (130, 360, 526) of the projection optics, and wherein the first layer has a planar portion (114, 528) on a second side of the first layer, opposite the first side of the first layer, at the optical axis; and a second layer (120, 340, 530) of a second cured material, wherein the second layer has a planar portion (122, 532) on a first side of the second layer at the optical axis (130, 360, 526), ​​and wherein the second layer has a second optical lens surface (124, 344, 534) on a second side of the second layer, opposite the first side of the second layer, at the optical axis; wherein the planar portion (114, 528) of the first layer is adjacent to the planar portion (122, 532) of the second layer at the optical axis, or wherein the planar portion (114, 528) of the first layer is separated from the planar portion (122, 532) of the second layer at the optical axis only by one or more coating layers (140, 330, 544); and wherein the projection optics further comprises the following features: a backside structure (200, 410, 546) and a cavity (210, 540, 548); wherein a first surface of the backside structure on the second side of the second layer is adjacent to the second layer (120, 340, 530), and wherein the cavity (210, 540, 548) is arranged between the backside structure and the second optical lens surface (124, 344, 534) on the optical axis (130, 360, 526). [45] Method for producing an optical structure (100a-c, 500), the method having the following features: Forming a first layer (110, 310, 522) of the optical structure, wherein the formation of the first layer has the following features Forming and curing a first curable material on a first mold structure (320) to form the first layer such that a first optical lens surface (112, 312, 524) is formed on a first side of the first layer where the first layer is adjacent to the first mold structure; and Providing a second layer (120, 340, 530) of the optical structure on a second side, opposite the first side, of the first layer, while the first layer is adjacent to the first mold structure on the first side of the first layer wherein the provision of the second layer (120, 340, 530) has the following features: Forming and curing a second curable material on the second side of the first layer (110, 310, 522) using a second mold structure (350) to form the second layer, such that a second optical lens surface (124, 344, 534) is formed on a second side of the second layer, on which the second layer is adjacent to the second mold structure and which faces away from the second side of the first layer; and such that the second optical lens surface is aligned with the first optical lens surface (112, 312, 524) at the optical axis (130, 360, 526) of the optical structure (100a-c, 500); and Providing one or more coating layers (140, 330, 544) between the first and second layers (120, 340, 530); wherein a thickness of a coating layer of the one or more coating layers (140, 330, 544) between the first and the second layer is in each case at most 10% or at most 5% or at most 2% or at most 1% of the thickness of the first layer (110, 310, 522) or the thickness of the second layer (120, 340, 530). [46] Method for producing an optical structure (100a-c, 500), the method having the following features: Forming a first layer (110, 310, 522) of the optical structure, wherein the formation of the first layer has the following features Forming and curing a first curable material on a first mold structure (320) to form the first layer such that a first optical lens surface (112, 312, 524) is formed on a first side of the first layer where the first layer is adjacent to the first mold structure; and Providing a second layer (120, 340, 530) of the optical structure on a second side, opposite the first side, of the first layer, while the first layer is adjacent to the first mold structure on the first side of the first layer wherein the provision of the second layer (120, 340, 530) has the following features: Forming and curing a second curable material on the second side of the first layer (110, 310, 522) using a second mold structure (350) to form the second layer, such that a second optical lens surface (124, 344, 534) is formed on a second side of the second layer, on which the second layer adjoins the second mold structure and which faces away from the second side of the first layer; and such that the second optical lens surface is aligned with the first optical lens surface (112, 312, 524) at the optical axis (130, 360, 526) of the optical structure (100a-c, 500); Removing the second mold structure (350) from the second layer (120, 340, 530) and bonding a first surface of a backside structure (200, 410, 546) to the second layer on the second side of the second layer such that the second optical lens surface (124, 344, 534) and the first surface of the backside structure form a cavity (210, 540, 548) at the optical axis. [47] Method for producing an optical structure (100a-c, 500), the method having the following features: Forming a first layer (110, 310, 522) of the optical structure, wherein the formation of the first layer has the following features Forming and curing a first curable material on a first mold structure (320) to form the first layer such that a first optical lens surface (112, 312, 524) is formed on a first side of the first layer where the first layer is adjacent to the first mold structure; and Providing a second layer (120, 340, 530) of the optical structure on a second side, opposite the first side, of the first layer, while the first layer is adjacent to the first mold structure on the first side of the first layer wherein the provision of the second layer (120, 340, 530) has the following features: Forming and curing a second curable material on the second side of the first layer (110, 310, 522) using a second mold structure (350) to form the second layer, such that a second optical lens surface (124, 344, 534) is formed on a second side of the second layer, on which the second layer is adjacent to the second mold structure and which faces away from the second side of the first layer; and such that the second optical lens surface is aligned with the first optical lens surface (112, 312, 524) at the optical axis (130, 360, 526) of the optical structure (100a-c, 500); wherein the method is performed on a wafer level to provide a plurality of optical structures (100a-c, 500) and / or wherein the method for obtaining a plurality of optical structures (100a-c, 500) is carried out in an array arrangement, and the method further comprising the following feature: Performing singulation to separate optical structures of the plurality of optical structures.

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