Optical devices and methods for imaging an object area

Abstract

An optical device comprises a first optical array for imaging an object region, a second optical array, and an objective optical system. The second optical array is arranged between the first optical array and the objective optical system and is configured to image apertures of the first optical array onto a common entrance pupil region of the objective optical system.

Description

[0001] The present invention relates to optical devices and methods for imaging an object region, such as an imaging optical device and a projector. The present invention further relates to an inverse plenoptic arrangement.

[0002] Multi-channel imaging systems or multi-aperture imaging devices, such as snapshot-capable multi- / hyperspectral cameras, in which multiple individual images are imaged on a common image sensor, such as a contiguous 2D pixel array, typically have very short focal lengths in the lower millimeter range. Due to the sometimes large cover glass distance and the cover glass thickness of the image sensor relative to the actual focal plane array (FPA), very short focal lengths are either impossible or extremely difficult to achieve. Furthermore, the fill factor—that is, the illuminated or usable area relative to the total area on the image sensor—decreases because suitable aperture structures must be implemented between the micro-optical multi-channel imaging system and the image sensor. These aperture structures can only inadequately ensure crosstalk into neighboring imaging channels simultaneously or result in significant artificial vignetting.

[0003] In addition, due to the tolerances within the image sensor and the multi-channel imaging system, it is often necessary to perform active adjustment of the systems, which is time-consuming and costly.

[0004] In principle, there are two variants that can solve this problem. According to one variant, the cover glass is removed from the image sensor in order to position the micro-optical camera module, including the aperture structures, closer to the FPA. This variant has the disadvantage that bond wires are unprotected and / or cooling can no longer be guaranteed. However, for image sensors for the mid-wavelength infrared (MWIR) or long-wavelength infrared (LWIR) range, it is usually necessary to vacuum encapsulate the image sensor to ensure a long service life. Furthermore, a dry environment or a clean room is required for handling to minimize dust exposure to the image sensor. This makes the first variant extremely complex and disadvantageous.

[0005] According to a second variant, an optical system with a retrofocus approach, i.e., a negative-positive combination, is extended to achieve a short focal length through a long overall length of the components. However, this requires a disadvantageous and complex correction of the optical components, which increases costs. Furthermore, the clear aperture of the optical surface is limited by the channel spacing, and / or, with clear apertures larger than the image circle of the image sensor, the fill factor is reduced.

[0006] Optical devices that can provide optics with short focal lengths and, at the same time, a high fill factor with respect to an image sensor or image generator would be desirable.

[0007] An object of the present invention is therefore to provide optical devices and a method for imaging an object area which enable the use of optics with short focal lengths and at the same time provide a high fill factor of an imager or image sensor.

[0008] This problem is solved by the subject matter of the independent patent claims.

[0009] A core idea of ​​the present invention is to have recognized that the use of two optical arrays connected in series for respective partial images of an object area with the additional use of an objective lens for jointly illuminating or imaging the optical arrays enables both the use of short focal lengths and a high fill factor.

[0010] According to one embodiment, an optical device comprises a first optical array for imaging an object region, a second optical array, and an objective lens. The second optical array is arranged between the first optical array and the objective lens and is configured to image apertures of the first optical array onto a common entrance pupil region of the objective lens. This enables advantageous imaging of the object region onto an image sensor arranged behind the objective lens and, moreover, mounting of the optical device independently of the image sensor, so that a shortening of the distance to the image sensor is possible but no longer necessary.

[0011] This approach can also be readily implemented for a reversed beam direction, so that according to one embodiment, an optical device is provided, comprising a first optical array for projecting an image and a second optical array, as well as an objective optical system. The second optical array is arranged between the first optical array and the objective optical system, wherein the objective optical system is configured to project the image onto apertures of the second optical array as partial images, and wherein the optical system of the first optical array is configured to project the partial images from the second optical array onto a projection surface.

[0012] According to one embodiment, a method for imaging an object region comprises receiving light from the object region with a first optical array and imaging individual images of the first optical array with a second optical array. The method includes imaging individual images of the second optical array with a common objective lens arranged in an intermediate image region of the second optical array.

[0013] Further advantageous embodiments of the present invention are the subject of dependent patent claims.

[0014] Particularly preferred embodiments of the present invention are explained below with reference to the accompanying drawings. They show: Fig. 1a-b show schematic side sectional views of optical devices according to embodiments with a segmented or matching field of view; Fig. 2 is a schematic side sectional view of an optical device according to an embodiment, with a mechanical interface for coupling to an image sensor; Fig. 3a is a schematic side sectional view of an optical device according to an embodiment, in which the image sensor is part of the optical device; Fig. 3b is a schematic side sectional view of the optical device in a state where a ratio of distances between optics versus the Fig. 3a is enlarged to change an image scale of an objective lens; Fig. 4 is a schematic side sectional view of an optical device according to an embodiment, with a sun visor structure; Fig. 5 a schematic representation of an object circle of an objective optics described herein according to an embodiment in an intermediate image plane; Fig. 6 one to the Fig. 5 comparable representation of an object circle of the objective optics, wherein the optical channels of the first and / or second objective array have a polygonal configuration according to one embodiment; and Fig. 7 a schematic representation of a flowchart of a method for imaging an object area according to an embodiment.

[0015] Before exemplary embodiments of the present invention are explained in more detail below with reference to the drawings, it is pointed out that identical, functionally equivalent or equivalent elements, objects and / or structures in the different figures are provided with the same reference numerals, so that the description of these elements shown in different exemplary embodiments is interchangeable or can be applied to one another.

[0016] The embodiments described below are described in conjunction with numerous details. However, embodiments may also be implemented without these detailed features. Furthermore, for clarity, embodiments are described using block diagrams instead of detailed illustrations. Furthermore, details and / or features of individual embodiments may be readily combined with one another, unless explicitly described otherwise.

[0017] The exemplary embodiments described below relate to optical arrays and the use of optical arrays. Some of the optical arrays discussed herein are micro-optical arrays using micro-optics. Micro-optics can comprise microlenses, a plurality of microlenses, for example as a lens stack or the like, or other optical elements, which can also include beam-deflecting elements, refractive elements, diffractive elements, lens sections, or the like.

[0018] Optical arrays described herein may be formed in one dimension, but are not limited to this, and may also comprise, for example, a two-dimensional arrangement of optics. This enables a correspondingly one-dimensional or two-dimensional segmentation of the object area.

[0019] Fig. Figure 1a shows a schematic side sectional view of an optical device 10 according to an embodiment, which can be used both for imaging an object region 12 and for projecting an image. The optical device 10 comprises a first optical array 14 with a plurality of optics 161, 162, which can be arranged in a one-dimensional or two-dimensional arrangement. A one-dimensional arrangement is understood to mean that optics or optical centers thereof are arranged along a direction or line.

[0020] The optical device 10 comprises a second optical array 18 having a plurality of optics 221 and 222. Preferably, each of the optics 221 or 222 is assigned to one of the optics 161 or 162, respectively. An assignment in the other direction is also possible, i.e., each of the optics 161 and 162 can be assigned to one, and in particular to exactly one, optic 221 or 222. As explained above, each of the optics 161, 162, 221, and 222, individually considered, can comprise a lens, a lens stack, a metal lens, a diffractive element, a refractive element, or combinations thereof.

[0021] The optical device 10 further comprises an objective lens system, wherein the arrangement of the first array 14, the second array 18, and the objective lens system 24 is implemented such that the second optical array 18 is arranged between the first optical array 14 and the objective lens system 24. The second optical array 18 is designed to image apertures of the first optical array 14 onto a common entrance pupil region 26 of the objective lens system 24. The entrance pupil region 26 can comprise the entrance pupil of the objective lens system 24, i.e., the image of a physical aperture or the imaging power of the objective lens system 24, but can also deviate from this within a tolerance range of ±5%, ±3%, preferably less, approximately ±2%, preferably less. A high degree of agreement leads to the avoidance of disadvantages that may arise from the deviations.If the entrance pupil of the lens optics 24 becomes overfilled, light from the object area still being imaged by the second optical array 18 may be lost. If the pupil is underfilled, in another case, while all of the light from the second optical array 18 may be imaged, the effective F-number increases, causing the image obtained on the image sensor to become darker or to be imaged with lower intensity, and the resolving power to decrease, which is also disadvantageous.

[0022] It is possible that in an optical device described herein there is an effect that an inner or central channel, such as comprising optics 162 and 522 of the optical device 20 in Fig. 2, which transmits or deflects the entire light, and the peripheral channels, such as optics 161 / 221 and 163 / 223, experience vignetting. In a case where the pupil position is not correctly determined due to the described deviation, larger field angles are more strongly vignetting, and a detrimental loss of spatial information may occur.

[0023] If the deviation is kept within the tolerance range of ± 5% or less, this effect can be easily tolerated. However, if the described light loss is not problematic, a larger deviation can also be implemented, which can, for example, allow for easier manufacturing. The specified values ​​may vary depending on the position and / or size of the lens optics; for example, smaller relative tolerances are advantageous for lens optics with larger dimensions, such as diameters.

[0024] The optics 16 and / or 22 described herein are, in particular, micro-optics, which can have optics with diameters ranging from a few hundred nm to millimeters. Scaling up to macro-optics is readily possible. The objective optics 24 can also be designed as a macro-optic system when the optics 16 and / or 22 are implemented as micro-optics, although a micro-optic system can also be used alternatively.

[0025] The illustrated arrangement allows partial regions 281 and 282 of the object region 12 to be converted into partial images 321 and 322, whereby an image sensor used to receive the partial images 321 and 322 is not shown. The image sensor can be part of another device to which the optical device 10 is coupled, for example by means of a mechanical interface, or can also be part of the optical device 10. The arrangement of the optical arrays 14 and 18 beyond the objective optics 24 relative to the image sensor makes it possible to use large focal lengths of the optics 161, 162, 221, and 222, since the distance of the optics from one another and also from the objective optics 24 can be adjusted almost arbitrarily without having to intervene in the structure of the image sensor or employing other disadvantageous concepts.

[0026] The optical device 10 can also be readily used as a projector. Put simply, the partial images 321 and 322 could also be projected into the object area 12 or onto a projection surface using the optical arrays 14 and 18 and the objective optical system 24. In this embodiment, the first optical array 14 is arranged adjacent to the second optical array 18 for projecting an image. Furthermore, the objective optical system 24 is provided, and the second optical array 18 is arranged between the first optical array 14 and the objective optical system 24. The objective optical system 24 is designed to project the image 321, 322 onto apertures of the second optical array 18, i.e., the optical systems 221 and 222, as partial images. Optics 161 and 162 of the first optical array 14 are designed to project the partial images from the second optical array 18 onto a projection surface not shown.

[0027] Fig. 1b shows a schematic side sectional view of an optical device 10' according to an embodiment in which the partial regions 281 and 282 of the optical device 10 overlap or have a nearly complete or complete overlap, so that the partial images 321 and 322 can have a matching image content, which is advantageous, for example, if different optical channels are adapted to capture different partial images 321 and 322 with respect to different spectral properties, for example to obtain a multispectral view of the object region 12.

[0028] Fig. Figure 2 shows a schematic side sectional view of an optical device 20 which can be used both for imaging an object area and for projecting images.

[0029] In the presentation of the Fig. 2, the first optics array 14 comprises, for example, the optics 161-163, wherein a two-dimensional arrangement of optics is preferably implemented. The optics 161 is assigned to the optics 221 of the second optics array 18. Correspondingly, the optics 162 is assigned to the optics 222 of the second optics array 18, and the optics 163 is assigned to an optics 223 of the second optics array 18. Based on such an assignment, optical channels can be formed that can comprise the optics 161 and 221; 162 and 222; and 163 and 223, and can, for example, meet in the objective optics 24 or have an overlapping course there. In particular, the optics 221 and 223 located away from a main viewing direction 56 of the optical device 20 can comprise decentered lenses or lens sections in order to effect the corresponding deflection of the beam paths.A design of one or more optics of the first optics array 14, the second optics array 18 and / or the objective optics as decentered lens elements or decentered optics is the subject matter herein of embodiments of the present invention.

[0030] The optical device 20 may comprise an interface 34 that may enable a mechanical coupling with a coupling device 25, which may have an image sensor 36 onto which the objective optics 24 may image partial images 321-323 of the object area 12. Unlike in the Fig. 1a, the partial images 321-323 can also be generated based on a beam guidance of the optical channels, for example in accordance with the Fig. 1b may be directed at a same object 38 in the object region 12. The image sensor 36 may comprise any desired image sensor, for example, a complementary metal oxide semiconductor (CMOS) sensor, a charge-coupled device (CCD) image sensor, an InGaAs image sensor, an image sensor with colloidal quantum dots (CQDs), or a sensor for other imaging purposes, such as a bolometric sensor and / or an array of photoacoustic sensors.

[0031] The mechanical interface 34 can be configured to couple the optical device 20 to the image sensor 36, i.e., an image sensor array. Alternatively, it is possible for the image sensor array, i.e., one or more image sensors, to be part of the optical device 20. In this case, the optical device 20 comprises an image sensor array, with the objective optics 24 configured to image the object region 12 onto the image sensor array.

[0032] In one embodiment of the optical devices described herein, the device comprises a diaphragm structure 42 acting on the second optical array 18, which is arranged adjacent to the second optical array 18. This diaphragm structure can be used to limit the field of view of the optical device 20 and / or a projection area illuminated by the optical device 20 and can provide stray light suppression.

[0033] Independently of the aperture structure 42, a stray light-suppressing structure 44 can be arranged as part of the optical device 20 to suppress stray light. The stray light-suppressing structure 44 can be arranged between the first optical array 14 and the second optical array 18, as well as between optics 161-163 of the first optical array 14, and can be designed to suppress crosstalk of stray light between adjacent optical channels of adjacent optics 161-163 of the first optical array 14. The effect can also be achieved for the optics 221-223 of the second optical array 18. The stray light-suppressing structure 44 can be partially opaque or absorbent, at least in the wavelength range relevant to the image sensor 36; for example, ceramic materials or polymer materials and coated metal alloys can be suitable for this purpose.The stray light suppressing structure 44 may have a flat or preferably roughened surface which is configured to scatter and / or assist absorption of radiation, which may be referred to by the English term baffle structure.

[0034] The objective optics 24 may include a diaphragm structure 46, wherein the diaphragm structure 46 may also be designed as an individual element for the objective optics 24 in order to further improve the imaging quality of the optical device 20. In this respect, the diaphragm structure 46 is an advantageous embodiment of the exemplary embodiments described herein, but is optional. Fig. 2 further shows that, in an optional embodiment, the objective optics 24 can comprise two or more lenses 481 and 482, which, for example, form a lens stack. This allows for precise adaptation of the optical device 20, in particular to different types, types, or sizes of image sensors 36, for example by changing the position or design of the objective optics 24 relative to the optical arrays 14 and / or 16 or the mechanical interface 34.

[0035] The mechanical interface 34 allows the lens optics 24 to be designed as a commercially available optic—in other words, an optic from a catalog. The improved imaging properties can be achieved by the optical device 20, which can be easily coupled to the lens optics 24 via the mechanical interface 34, which can be aligned with the image sensor in the usual way without unnecessary additional effort.

[0036] In Fig. 2 is based on the Fig. 1, 522, and 523, which are obtained by the optics 161, 162, and 163, respectively, for the object region 12, illustrate that, in a preferred embodiment of an optical device, the second optics array 18 is arranged in an intermediate image region of the first optics array 14. This enables, in particular, a particularly close arrangement of the optics arrays 14 and 18 to one another.

[0037] Likewise, in the Fig. 2 shows that in a preferred embodiment, the objective optics 24 is arranged in an intermediate image region of the second optics array 18, which also enables a small distance between the second optics array 18 and the objective optics 24.

[0038] A particularly preferred embodiment of the exemplary embodiments described herein includes positioning the elements such that a size of an intermediate image of the second optical array 18, which may be determined by the aperture structure 46, in the intermediate image region substantially corresponds to a size of an object field of the objective optics 24. As illustrated by the beam paths, the entire region 54 between elements of the aperture structure 46 is preferably utilized to image the object region 12.

[0039] According to a preferred embodiment, the optical device can be configured such that an image field of the first optical array 14 substantially coincides with an object field of the objective optics 24, whereby deviations between the image field and the object field of ±10%, ±5%, or ±2% are possible without sacrificing significant advantages of the configuration described herein. Deviations from this can lead to an additional dead zone on the image sensor or the imaging of only a section of the object area, depending on whether the image field is larger than the object field or vice versa.

[0040] In other words, the multi-aperture imaging system 14 can generate an array of intermediate images on or near the field lens array 18. To suppress crosstalk, a stray light suppressing structure 44 is provided, implemented, for example, as a 3D baffle structure, which can also be placed in front of the multi-aperture imaging system as an alternative or in addition, see Fig. 4, and can be used there as a sun visor. A global aperture 42 is arranged in the intermediate image plane. The intermediate image is imaged by the lens 24 at a scale of, for example, 1:1 onto an image sensor 36 to be coupled, and transmits the array of partial images. This can be achieved, for example, by the optical device 20 being appropriately adapted to the coupling device 25, for example with knowledge of the image sensor(s) used as well as the geometries and distances, as is usual, for example, for known single-channel lenses. A selection of the ratio of distances s between the second optical array 18 and the optics 24 on the one hand and a distance s' between the optics 24 and the image sensor 36 can be used to adjust the scale.A module, which, for example, comprises the optical arrays 14 and 18 as well as the stray light-suppressing structure 44 and the aperture 42, can be formed as a single element and placed in front of the lens 24 and can also be replaced, for example, with another multi-aperture imaging system with different optical properties. Such a module 58 can also have a mechanical interface that is configured for coupling to the lens 24 and enables replacement of the module 58 with respect to the lens 24 or of the lens 24 with respect to the module 58. In a further embodiment, the mechanical interface 34 can also be part of the module 58, for example, by designing the coupling device 25 such that the lens 24 is also part of the coupling device 25.In a further embodiment, the module 58, the objective optics 24 and the coupling device 25 may represent three elements or devices to be coupled to one another, which can be individually connected to one another.

[0041] Fig. 3a shows a schematic side sectional view of an optical device 30 according to an embodiment, in which, unlike in the optical device 20, the image sensor 36 is part of the optical device. Optical channels 621-623, each comprising an optic 16 of the first optical array 14 assigned to the optical channel 62 and an optic 22 of the second optical array 18 assigned to the optical channel, can be aligned such that the objective optic 24 comprises a channel-global lens or optic 24 for the plurality of optical channels 621-623, i.e., a lens acting for a plurality, but preferably for all, optical channels.

[0042] By changing the ratio of the distances s to s', the scale with which the intermediate image of the objective optics 24 is imaged onto the image sensor 36 can be adjusted. According to exemplary embodiments, it is preferred that the objective optics have an image scale of at least 1:0.9 and at most 1:4, preferably of at least 1:1 and at most 1:3, and particularly preferably of at least 1:1 and at most 1:2.

[0043] Fig. 3b shows a schematic side sectional view of the optical device 30 in a state where the ratio of the distances s:s' is increased. The image scale of the objective optics 24 is selected here, for example, as 1:2. Such values ​​of a ratio and / or distance changes can easily be selected differently. With reference to the optical device 20, this can be achieved, for example, by a modified coupling device 25 and / or by using a focusing device that can be configured to adapt or adjust a position of the objective optics 64 along the main viewing direction 56. This can be used, for example, to project smaller partial images 32'1-32'3 onto an equally large or reduced-size image sensor 36. This configuration with regard to the modified positioning of the objective optics 24 can also easily be implemented in the optical device 10 and / or 20.

[0044] Fig. 4 shows a schematic side sectional view of an optical device 40 according to an embodiment, which may include the optical arrays 14 and 18 and the objective optics 24, as described in connection with the optical device 20 and 30. The image sensor 36 may be part of the optical device 40, but may also form an external component, as described in connection with the optical device 20. The respective optional configurations of the aperture structures 42 and 46, as well as the optional arrangement of the stray light-suppressing structures 44, are shown by way of example.

[0045] The optical device 40 may have a diaphragm structure 46, which may be formed identically or similarly to the stray light suppressing structure 44, but is arranged on a side of the optics 161-163 of the first optics array 14 facing away from the objective optics 24, for example to serve as a sun visor and to reduce or prevent the entry of corresponding stray light.

[0046] Fig. Figure 5 shows a schematic representation of an object circle 66 of an objective optics 24 described herein in the intermediate image plane. Furthermore, intermediate image circles 681-68 10 , which are assigned to the optical channels of the multi-aperture imaging system of the optical device 50. It can be seen that the two-dimensional arrangement of optical channels is, for example, in a hexagonal pattern of possibly round optics. The intermediate image circles 681-68 10are imaged globally by the lens optics 24, as shown by the object circle 66. The lens optics 24 effects a transfer to the image sensor 36 with its boundary 72 of the possibly rectangular pixel area, which can also vary arbitrarily. For example, an image scale of 1:2 is shown, as is the case for the optical device 30 in the Fig. 3b. An image circle 74 of the lens 24 can be arranged for imaging on the image sensor 36. Each of the intermediate image circles 681-68 10 associated image circles 761-76 10 , which are imaged on the image sensor 36, are in the Fig. 5 is also visible.

[0047] For example, the object circle 66 can be imaged completely or almost completely, for example, reduced in size using an image scale.

[0048] Fig. 6 shows a Fig. 5 shows a comparable representation of an object circle 66 of the objective optics 24, wherein the optical channels of the first and / or second objective arrays 14 and 18, respectively, have, for example, a polygonal, in particular rectangular and particularly preferably square, configuration, which enables a high fill density and / or a low degree of unused dead zones. These are arranged, for example, in a 3x3 array in a two-dimensional pattern, which can be expressed in a corresponding arrangement of the intermediate image circles 681-689.

[0049] As it is in the Fig. 6 is also shown, a particularly good adaptation of the arrangement of the image circles 761-769 to the boundary 72 of the image sensor 36 can be achieved and this can be used to a particularly high degree without parts of optical channels not being detected by the image sensor 36 or parts of the image sensor remaining unilluminated, as is the case in the Fig. 5 is the case.

[0050] In other words, the Fig. 6 shows a representation of the object circle 66 of the lens in the intermediate image plane with the individual, for example, rectangularly arranged intermediate image areas 681-689 of the multi-aperture imaging system. This is then transferred to the image sensor 36 with its boundary 72 of the rectangular pixel area at an image scale of, for example, 1:2. The image circle 74 of the lens images onto the image sensor 36. The rectangular partial images 761-769 on the image sensor are shown.

[0051] As it is related to Fig. 5, the object circle 66 can be imaged completely or almost completely, for example, reduced in size using an image scale.

[0052] The described two-dimensional arrangement of optics of the optical arrays 14 and / or 18 can refer to a plane perpendicular to a main viewing direction or optical axis of the optical device, such as the main viewing direction 56 described in connection with the optical devices 20, 30, and 40. The corresponding plane can, for example, be inclined relative to the image sensor 36, which nevertheless allows the preservation of a two-dimensional pattern in the virtual projection plane.

[0053] In embodiments of the present invention, the optical channels can be individually, individually or in groups, but also globally, with an optical system of the optical array 14 assigned to the optical channel and an optical system of the optical array 18 assigned to the optical channel. The optical device can comprise a filter structure arrangement configured to filter light from at least one optical channel. This enables a further improvement in imaging quality.

[0054] Optical devices 10, 20, 30, 40, 50 and / or 60 described herein can also be readily used for projecting images.

[0055] Fig.7 shows a schematic representation of a flowchart of a method 700 for imaging an object region, for example, using an optical device described herein. A step 710 of the method 700 comprises receiving light from the object region with a first optical array. A step 720 comprises imaging individual images of the first optical array with a second optical array. A step 730 comprises imaging individual images of the second optical array with a common objective lens arranged in an intermediate image region of the second object array.

[0056] In an optional but advantageous embodiment of the method 700, the second optics array is arranged between the first optics array and the objective optics and images apertures of the first optics array onto a common entrance pupil region of the objective optics.

[0057] The embodiments described herein particularly advantageously enable imaging or projection using multi-aperture arrays. While DE 10 2011 114 325 A1 uses a plenoptic camera that projects an image onto a projection surface and is viewed through a lens system / objective, this has the disadvantage that vignetting effects occur toward the edge of the projection surface, since the convergence of the light beams of the lens array in the projection surface does not match the acceptance angle of the objective. In addition, this projection plane can produce negative image artifacts compared to an aerial image.

[0058] The embodiments described herein also have advantages over US 2007 / 023094 A1. In the cited document, an array of lenses (diverging lenses) and prisms is used in front of a main lens to view the object from different angles, which are then imaged by the main lens in different views onto the photodetector array. In this case, no intermediate image is generated. Therefore, large macroscopic lens arrays and prism arrays are required, which are complex to manufacture and must cover the camera's field of view, otherwise a large amount of image sensor area is wasted or remains unused. The various approaches generated in this way are unsuitable for multi-modal approaches, since the image information differs significantly between the channels.

[0059] In contrast, embodiments enable the use of a two-stage imaging method. A multi-channel imaging system generates an intermediate image (aerial image) in an intermediate image plane. This intermediate image is imaged onto an image sensor by a lens 24, for example at an image scale of approximately 1:1 to 1:3, and can have a standard mount connection, such as an F / C mount or the like, as a mechanical interface 34. Additionally, a microlens array, such as freeform microlenses, is located in or near the intermediate image. This array images the aperture of the first multi-channel imaging system onto the entrance pupil of the downstream lens in order to avoid vignetting losses. Through downstream imaging using a lens, the multi-channel image is imaged sharply and with a high fill factor onto the image sensor.

[0060] Embodiments allow for passive mounting of the multi-channel imaging system in front of the lens. Embodiments allow for merely aligning the image field of the multi-channel imaging system with the object field of the macro lens 24, so that the image field of the multi-channel imaging system coincides with the object field of the macro lens, thus avoiding unnecessary image loss or unused image sensor area. Fine adjustment by focusing the macro lenses remains possible.

[0061] The effect of an image-side 3D aperture array, which may be used in other devices with considerable effort, can be integrated on both sides of the intermediate image plane by implementing embodiments described herein in order to integrate the FPA without a distance to the image plane and / or to integrate a stronger suppression of stray light through the possibility of a 3D aperture before and / or after the intermediate image plane.

[0062] Embodiments of the present invention may include a miniaturized multi-channel imaging system 14 and additional 3D aperture structures 44. An array of field lenses 22, e.g., in the form of a freeform microlens array, and an additional global field stop 42 are arranged in the intermediate image plane. An objective lens system has an image scale of approximately 1:0.9 to 1:4 or 1:1 to 1:3. An image sensor may, for example, be configured as a CMOS / CCD image sensor, but may also comprise other elements, such as a bolometer array or the like, and may be part of the optical device or may be coupled to it.

[0063] The multi-channel imaging system can have the following properties: It can have a number of n>2 channels distributed in a 1D or 2D arrangement, such as rectangular, hexagonal, or the like. Alternatively or additionally, the image acquisition modalities can be expanded, for example, by spectral filters, such as graduated filters, bandpass filters, or the like, by polarization filters, or others in the multi-channel system. Alternatively or additionally, the multi-channel system can have a field of view division, as described in connection with the optical device 10, and / or strabismus channels, as shown, for example, for the optical devices 20, 30, and / or 40. A 3D aperture structure, such as a baffle structure 42, can prevent or at least suppress stray light or crosstalk into adjacent optical channels.

[0064] The field lens array 18 can enable imaging of the respective aperture from the multi-channel imaging system 14 onto the entrance pupil of the objective 24. A design, such as a freeform microlens array, phase plate, diffractive lens array, or the like, is readily possible. The global aperture 42 prevents stray light outside the field of view.

[0065] For optimal utilization of the image area on the image sensor, the lens 24 can be designed such that the corresponding object area is approximately or exactly the same size as the multi-channel intermediate image. This can involve adapting one or more components to the corresponding spectral range.

[0066] Examples of implementation offer several advantages over known concepts: • an easily exchangeable multi-channel imaging system in front of the lens (modularity, handling) without readjustment; • intrinsic zoom function by focusing the lens on different distances in the inter-image area; • Transfer of a large depth of field (extended depth of field) of the multi-channel system, especially when using short focal lengths, with the lens to the image sensor, which enables the generation of an all-in-focus image with a single shot; • Compared to classic plenoptic camera systems, a better light yield can be achieved, since no unused dead zones are created when the aperture is superimposed, which, in addition to a better light yield, also enables a reduction in stray light; • it enables the realization of large back-focal lengths, which enables integration into camera systems with standard lens connections via interface 34; integration into camera systems with a large sensor-cover glass distance is also possible; • A reduced macro lens allows the use of array camera modules that have a comparatively large channel pitch, which facilitates the integration of structurally integrated filters for spectral filtering or polarization filtering.

[0067] Embodiments can be used in the field of classic multi-aperture imaging systems and offer a very compact design. Examples include multi- / hyperspectral cameras and polarization cameras. Embodiments can generally be used in multi-modal imaging and / or in cameras with field-of-view splitting, such as electronic cluster eyes. Embodiments described herein are also suitable for multi-channel cameras for achieving super-resolution. The optical systems described herein can be used in the visible wavelength range as well as, alternatively or additionally, in the ultraviolet (UV) range up to the LWIR range. Embodiments can be used in snapshot-capable imaging multispectral gas sensors and / or thermal sensors.

[0068] Although some aspects have been described in connection with a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also represent a description of a corresponding block, detail, or feature of a corresponding device.

[0069] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2011 114 325 A1

[0057] US 2007 / 023094 A1

[0058]

Claims

[1] Optical device comprising: a first optical array for imaging an object area and a second optical array; a lens optics; wherein the second optical array is arranged between the first optical array and the objective optics and is designed to image apertures of the first optical array onto a common entrance pupil region of the objective optics. [2] An optical device according to claim 1, wherein the second optical array is arranged in an intermediate image region of the first optical array. [3] Optical device according to claim 1 or 2, wherein the objective optics are arranged in an intermediate image region of the second optical array. [4] An optical device according to claim 3, wherein a size of an intermediate image in the intermediate image region substantially coincides with a size of an object field of the objective optics. [5] Optical device according to one of the preceding claims, wherein a plurality of optical channels comprises an optic of the first optical array associated with the optical channel and an optic of the second optical array associated with the optical channel; wherein the objective optic comprises a channel-global lens for the plurality of optical channels. [6] Optical device according to one of the preceding claims, wherein the objective optics has an image scale of at least 1:0.9 and at most 1:

4. [7] An optical device according to any one of claims 1 to 6, further comprising a mechanical interface for coupling the optical device to an image sensor array. [8] Optical device according to one of claims 1 to 6, further comprising an image sensor arrangement, wherein the objective optics are configured to image the object area onto the image sensor arrangement. [9] Optical device according to one of the preceding claims, wherein an image field of the first optical array substantially coincides with an object field of the objective optics. [10] Optical device according to one of the preceding claims, comprising a stray light suppressing structure which is arranged between the first optical array and the second optical array and between optics of the first optical array and which is designed to suppress crosstalk of stray light between optical channels of adjacent optics of the first optical array. [11] Optical device according to one of the preceding claims, comprising a diaphragm structure arranged between the first optical array and the object region and between optics of the first optical array. [12] Optical device according to one of the preceding claims, comprising a diaphragm structure acting for the second optical array, which is arranged adjacent to the second optical array. [13] Optical device according to one of the preceding claims, wherein a projection of the optics of the first optics array and the optics of the second optics array into a plane perpendicular to an optical axis between the first optics array and the objective optics results in a two-dimensional pattern. [14] Optical device according to one of the preceding claims, wherein a plurality of optical channels comprises an optic of the first optical array associated with the optical channel and an optic of the second optical array associated with the optical channel; wherein the optical device comprises a filter structure arrangement configured to filter light of at least one optical channel. [15] Optical device comprising: a first optical array for projecting an image and a second optical array; a lens optics; wherein the second optics array is arranged between the first optics array and the objective optics, wherein the objective optics are configured to image the image onto apertures of the second optics array as partial images; and optics of the first optics array are configured to project the partial images from the second optics array onto a projection surface. [16] A method for imaging an image comprising the following steps: Receiving light from an object area and with a first optics array for imaging the object area; imaging individual images of the first optics array with a second optics array; Imaging individual images of the second optical array with a common objective optics arranged in an intermediate image region of the second optical array. [17] Method according to claim 16, which is carried out in such a way that the second optical array is arranged between the first optical array and the objective optics and images apertures of the first optical array onto a common entrance pupil region of the objective optics.

Images