Beam combiner and illumination device

Abstract

The invention relates to a beam combiner (200) comprising: a first mirror (202) which has a first portion (204) and a second portion (206) which jointly define a first mirror plane (208); and a second mirror (210) which has a third portion (212) and a fourth portion (214) which jointly define a second mirror plane (216), the first mirror plane (208) and the second mirror plane (216) being arranged in a cross shape, the first portion (204) and the second portion (206) being spaced apart from one another and located on opposite sides of the second mirror plane (216); a holder (218) which holds the first portion (204) and the second portion (206) at a first side (220); and a connector (222) which mechanically couples the first portion (204) and the second portion (206) at a second side (224) different from the first side (220) such that the first portion (204) and the second portion (206) are immovable relative to one another at the second side (224).

Description

[0001] Beam combiner and lighting device

[0002] The present invention relates to a beam combiner and an illumination device, in particular an endoscope illumination device.

[0003] Imaging devices such as endoscopic or exoscopic devices that generate multispectral or hyperspectral images are known from the prior art. Multispectral or hyperspectral images have, in addition to two spatial dimensions, such as a conventional camera image, a spectral dimension. The spectral dimension encompasses several spectral bands (wavelength bands). Multispectral and hyperspectral images differ primarily in the number and width of their spectral bands.

[0004] Several imaging devices for generating such multispectral or hyperspectral images are known, particularly in the context of medical applications. For example, DE 20 2014 010 558 U1 describes a device for capturing a hyperspectral image of an examination area of ​​a body. The device includes an input lens for generating an image in an image plane and a slit-shaped aperture in the image plane for masking out a slit-shaped region of the image. The light passing through the aperture is spread out by a dispersive element and recorded by a camera sensor. As a result, the camera sensor can record a plurality of spectra, each with an associated spatial coordinate, along the longitudinal direction of the slit-shaped aperture.The described device is further configured to record additional spectra along the longitudinal direction of the slit-shaped aperture in a direction different from the longitudinal direction of the slit-shaped aperture. The method underlying this disclosure for generating multispectral or hyperspectral images is also known as the so-called pushbroom method.

[0005] In addition to the pushbroom method, there are other methods for generating multispectral or hyperspectral images. In the so-called whiskbroom method, the examination area or object is scanned point by point, and a spectrum is obtained for each point. In contrast, the staring method acquires multiple images with the same spatial coordinates. Different spectral filters and / or illumination sources are used from image to image to resolve spectral information. Furthermore, there are methods in which a two-dimensional multicolor image is decomposed into several individual spectral images using suitable optical elements such as optical slicers, lenses, and prisms. These individual images are simultaneously acquired on different detectors or detector areas. This is sometimes referred to as the snapshot approach.

[0006] As described in DE 10 2020 105 458 A1, multispectral and hyperspectral imaging devices are particularly suitable as endoscopic imaging devices. In this context, multispectral and / or hyperspectral imaging is a fundamental field of application, for example, for diagnostics and for assessing the success or quality of a procedure.

[0007] White light imaging is also used, particularly in medical imaging. Observed tissue is illuminated with white light, and images of the tissue are generated using a camera or other image capture sensor, which can then be displayed to a user.

[0008] Fluorescence imaging is also used, especially in medical imaging. Tissue is specifically illuminated in a specific wavelength range to excite fluorescent dye molecules that have been specifically introduced into specific entities, such as tissue regions. The resulting emitted light with a longer wavelength can be observed through a suitably selected filter, which can be used to filter out the excitation light.

[0009] Multimodal imaging devices allow the acquisition of white light images, multispectral images, fluorescence images, and / or hyperspectral images. Examples of such imaging devices include multimodal endoscopes and multimodal exoscopes. To implement different modes, illumination devices may be required that can be operated in different illumination modes to generate illumination light in different spectral ranges as needed.

[0010] Based on the prior art, the invention is based on the object of combining illumination light reliably and efficiently, with, in particular, minimal distortion of the spectrum of the illumination light. This object is achieved according to the invention by a beam combiner and an illumination device as described herein and defined in the claims.

[0011] The present invention provides a beam combiner. The beam combiner comprises a first mirror having a first section and a second section that together define a first mirror plane, and a second mirror having a third section and a fourth section that together define a second mirror plane, wherein the first mirror plane and the second mirror plane are arranged in a cross shape, wherein the first section and the second section are spaced from one another and arranged on opposite sides of the second mirror plane, a holder that holds the first section and the second section on a first side, and a connector that mechanically couples the first section and the second section on a second side different from the first side such that the first section and the second section are immovable relative to one another on the second side.

[0012] Furthermore, the present invention provides for the provision of an illumination device, in particular an endoscope illumination device, comprising at least one beam combiner according to the invention.

[0013] The beam combiner according to the invention allows illumination light from multiple lighting elements to be efficiently combined, for example with minimal light loss, and / or coupled into a common optical path. The mechanical stability of the mirrors and / or sections relative to one another results in high repeatability and / or reliability. According to the aforementioned features, tilting of the mirrors and / or sections relative to one another is at least significantly reduced. As a result, the spectrum of the illumination light is only minimally distorted when coupled into the common optical path. Furthermore, such a beam combiner allows for a compact design of the beam combiner itself and the illumination device. This is, for example, inexpensive and / or simple in terms of production and assembly. Secondly, light losses can be kept to a minimum thanks to a short optical path.Furthermore, the aforementioned features reduce the risk of stress fractures in the mirrors. Finally, it is advantageous that illumination light from at least three lighting elements can be coupled into a common optical path. This allows the required installation space for the lighting device to be kept to a minimum.

[0014] The inventors have recognized that illumination devices can comprise multiple lighting elements, each of which can provide illumination light with specific spectral properties, but that illumination light is expediently coupled into, for example, an endoscope or exoscope via only one optical path. The illumination light from the respective lighting elements must therefore be combined or coupled into a common optical path. At the same time, such illumination devices should be efficient, precise, compact, and / or accurate. For example, light losses due to a long optical path should be minimized and / or illumination light with at least virtually unadulterated spectral properties should be coupled into the common optical path. This is achieved by the features according to the invention.

[0015] The lighting device may comprise at least two lighting elements, wherein the beam combiner defines two different input sides, wherein the two lighting elements are each arranged on one of the input sides, and wherein the beam combiner is configured to couple light of the lighting elements into a common optical path.

[0016] The beam combiner can generally be an assembly designed to combine illuminating light, each of which defines a beam path. Combining can specifically mean that the illuminating light is coupled into a common optical path. For example, the beam combiner comprises three input sides and one output side, with two input sides being arranged opposite one another. Lighting elements, by means of which illuminating light is provided, can be provided on the opposite input sides. The beam combiner can deflect the illuminating light at least partially from the opposite input sides to the output side. Light emerging from the output side can be coupled and / or capable of being coupled into an endoscope or exoscope.The beam combiner allows light from the input sides to be combined so that it exits the output side along the common optical path. The first mirror and the second mirror can be elements with optical properties, such as light reflection and transmission, that are matched to the spectral properties of the light element-specific illumination light associated with the respective mirror.

[0017] The sections can each comprise a part of the first or second mirror. Each section can, for example, comprise 10% to 50%, in particular 25% to 50% and preferably 40% to 49% of the respective mirror, in particular based on a volume and / or an area of ​​the mirror. The first section and / or the second section preferably has a rectangular and / or square shape in a projection onto its main extension plane. The mirror planes defined by the sections can be planes with respect to which incident light and its transmitted and / or reflected spectral range are symmetrical. The sections jointly defining a mirror plane can, in particular, have at least substantially the same optical properties.

[0018] In this context, a cross-shaped arrangement of mirror planes can mean that the first mirror plane intersects the second mirror plane, or that the first mirror plane and the second mirror plane together enclose an angle. The angle enclosed by the mirror planes can be, for example, 45° to 90°, in particular 75° to 90°, and preferably 85° to 90°. In some embodiments, "cross-shaped" means at least substantially perpendicular.

[0019] The spatial spacing of the first section and the second section from one another does not necessarily mean that the first mirror is designed in several parts. Nevertheless, it can be provided according to the invention that the first mirror is designed in at least two parts. For example, the first section and the second section can be spaced from one another and arranged on opposite sides of the second mirror plane in such a way that at least substantially a part of the second mirror is arranged between the first section and the second section. The first section and the second section can in particular touch or mechanically contact at least a part of the second mirror. It can also be provided that a further part of the first mirror is provided between the first section and the second section.Furthermore, it can be provided that no part of the first mirror or the second mirror is arranged between the first section and the second section.

[0020] The mount can be a mechanical component designed to increase the mechanical stability of the beam combiner, in particular of the mirrors and / or the sections. A mount can be understood, in particular, as a device by which the mirrors and / or the sections are secured and / or held in a position such that the mirrors and / or the sections can be removed and / or moved from this position.

[0021] A beam combiner according to the invention can comprise multiple sides. The first side can, for example, be a side through which the first mirror plane and the second mirror plane extend. A further side can, for example, be a side opposite the first side. The first mirror plane and the second mirror plane can also extend through this further side. Still further sides of the beam combiner can be defined by outer edges of the mirrors. These can, for example, be aligned at least substantially perpendicular to the first side. In particular, these sides can be arranged in one of the first and / or second mirror planes.

[0022] The connector can be an element or component that is designed to increase the mechanical stability of the beam combiner, or of the mirrors and / or the sections, in particular of the first mirror and / or the first section and the second section. For example, the connector is designed to at least reduce a relative movement of the first section and the second section to one another. The mechanical coupling of the first section and the second section in this context can mean that a movement of one section causes a similar movement of the other section at least in terms of extent and direction. As a result, the first section and the second section are immobile relative to one another. Immobile is to be understood in the context of the function of the first mirror. Immobile can mean that the first section and the second section are immobile relative to one another depending on the application.are immobile relative to one another in such a way that the function of the mirror remains at least essentially constant, i.e., the mirror reliably reflects light without significantly influencing the spectral properties of the light. For example, a movement relative to one another, which occurs due to thermal expansion of the first and second sections, may be possible despite the immobility. In other words, negligible relative movements can be encompassed by the term "immobile."

[0023] The connector does not necessarily have to be located on the side with respect to which the first section and the second section are immobile relative to each other. Rather, the connector determines the immobility on the second side.

[0024] Furthermore, the second side can be arranged opposite the first side. This can increase the mechanical stability, safety, and / or reliability of the beam combiner.

[0025] In some embodiments, the second mirror is a single piece. This has the particular advantage that the second mirror is inherently stable and does not require a stabilizing element or device, such as a connector, to provide a reliable beam combiner.

[0026] Furthermore, the connector may comprise at least one groove in which the first section and / or the second section is at least partially received. The groove preferably has a length that is at least as long as the length of an outer edge of the corresponding section received in the groove.

[0027] This ensures particularly simple construction and assembly and reliable function.

[0028] According to a further development, the connector can comprise at least one further groove in which the third section and / or the fourth section is at least partially received. The further groove preferably has a length that is at least as long as the length of an outer edge of the corresponding section received in the groove. This feature also achieves particularly simple construction and assembly and reliable function.

[0029] Furthermore, the at least one groove of the connector can cross the at least one further groove of the connector. In particular, this can mean that the grooves of the connector run within the first mirror plane and the second mirror plane, with side walls of the groove being arranged parallel to the respective mirror plane. According to some embodiments, the first mirror and the second mirror can be flush on the second side. In particular, it is advantageous if the at least one groove of the connector crosses the at least one further groove of the connector. The connector can be plugged onto the first mirror and the second mirror in a simple manner.

[0030] In some embodiments, the connector is configured to at least restrict and / or prevent movements of the first section and / or the second section parallel to the second mirror plane. According to this feature, the first section and the second section on the second side are not only immovable relative to one another, but are also restricted in movement relative to the second mirror. For example, this can at least restrict and / or prevent joint tilting of the first section and the second section. Tilting would at least impair the function of the first mirror. This could change a beam path so that light is no longer or less efficiently coupled into the common optical path, for example due to a changed orientation of the mirror.In addition, a function that affects the spectral properties of illumination light could be impaired, for example, at least partially deflecting illumination light. The spectral properties of illumination light could be altered or distorted, for example, if it hits the mirror at a different angle. Therefore, for a particularly reliable, accurate, and precise beam combiner, it is advantageous to at least limit the tilting of the first section and the second section. Furthermore, however, movements of the first section and / or the second section parallel to the second mirror plane may be possible without impairing the function of the mirror. Thermal expansion of the sections and / or resulting distortions, for example, may be permitted.In particular, the connector can be configured to take thermal expansions into account and / or be designed to allow movements of the first section and / or the second section parallel to the second mirror plane that do not impair the function of the first mirror.

[0031] The connector may be formed in one piece. "Integral" should be understood in particular as meaning at least a materially bonded connection, for example, by a welding process, an adhesive process, an injection molding process, and / or another process deemed appropriate by a person skilled in the art. Furthermore, "single-piece" can also be understood as "one-piece." "One-piece" should be understood in particular as meaning formed in one piece, for example, by production from a single casting and / or by production using a single-component or multi-component injection molding process, and advantageously from a single blank. This can reduce manufacturing costs and assembly effort.

[0032] In addition, the connector can have a rectangular, in particular square, basic shape. A rectangular and / or square basic shape can include rounded and / or beveled corners of the basic shape. This can, in particular, increase the mechanical stability of the beam combiner. Furthermore, it can provide advantages during assembly and production. In particular, a square basic shape that is symmetrical is simple and / or inexpensive to manufacture and / or assemble.

[0033] In some embodiments, the connector has beveled and / or rounded corners. This can be advantageous, for example, when installing the beam combiner. Furthermore, it can provide a positive or partially positive connection with other components of the lighting device.

[0034] Furthermore, the connector can be made of plastic and / or rubber. For example, the connector can be a plastic casting and / or manufactured using an additive manufacturing process. It is particularly advantageous if the connector can be manufactured in just one, two, or three manufacturing steps.

[0035] In addition, the connector can have a damping function. A damping function can basically mean that energy, in particular kinetic energy, is dissipated through the connector. For example, vibrations between the first section and the second section can be dampened. In addition, impacts and / or vibrations can be dampened in such a way that the function of the first mirror glass and / or the second mirror glass is not permanently impaired by the impact and / or vibrations. Furthermore, vibrations that can occur, for example, during operation of the lighting device can be dampened in such a way that they are transmitted at least slightly to the beam combiner. The damping function can therefore also include a decoupling function.

[0036] In some embodiments, the first mirror and the second mirror jointly support the connector. In other words, the connector rests and / or sits on the mirrors. This can further increase the operating safety and reliability of the beam combiner.

[0037] According to some embodiments, the connector is formed integrally with the first section and the second section. In particular, this may mean that the first mirror is formed integrally. The connector may extend at least partially between the first section and the second section, which are spaced apart from one another and arranged on opposite sides of the second mirror plane. In such a case, the connector is provided from the same material as the first section and the second section. This allows for a particularly simple design and cost-effective production.

[0038] In some embodiments, the mount comprises at least one groove in which the first section and / or the second section is at least partially received. A mount with a groove represents a particularly cost-effective and / or easy-to-manufacture mount design. The depth of the groove can be adapted, in particular, to the mechanical requirements of the beam combiner. For example, a larger first mirror may require a deeper groove.

[0039] Furthermore, the mount comprises at least one additional groove in which the third section and / or the fourth section is at least partially accommodated. This feature also represents a particularly cost-effective and easy-to-manufacture mount design. The depth of the additional groove can be adapted, in particular, to the mechanical requirements of the beam combiner. For example, a larger second mirror may require a deeper additional groove.

[0040] In addition, the at least one groove of the holder can cross the at least one further groove of the holder. The two grooves can together form a cross groove. This can mean, in particular, that at least one of the first groove and the further groove is continuous or extends over at least the entire length of the first and / or second mirror. Advantageously, the holder can be designed symmetrically at least with respect to the first groove and the further groove. This can result in there being no preferred installation direction for a mirror in the holder. In addition, the holder can have a cross-shaped base area. In particular, the holder can extend at least partially along the first mirror and the second mirror. This can result in material savings, weight savings and / or advantages during installation in the lighting device.

[0041] In some embodiments, the mount has a length and a width, with the first mirror and the second mirror having an extension that corresponds to at least 80%, preferably at least 90%, and particularly preferably at least 95% of the length and / or width. This allows for further increasing mechanical stability. Furthermore, vibrations or the vibration behavior of the first mirror and / or the second mirror can be improved.

[0042] In addition, the mount can comprise side guides configured to hold the first mirror and / or the second mirror laterally. This can further increase mechanical stability and operational reliability. The side guides can have a length, and the first mirror and the second mirror can have a further extension, with the length of the side guides corresponding to 10% to 90%, preferably 15% to 70%, and particularly preferably 25% to 40% of the further extension.

[0043] Furthermore, the mirrors can have play in the side guides. This can, in particular, prevent thermal expansion from increasing stress on the first and / or second mirrors and / or causing them to become deformed.

[0044] In addition, the side guides can hold the first mirror and / or the second mirror on two opposite sides, each different from the first side and the second side. This can mean that the first mirror and / or the second mirror is held on at least three sides in total. Advantageously, the first mirror and / or the second mirror are held in an edge region. Starting from one of the sides, in particular from a side different from the mirror surface, the edge region can each amount to, for example, a maximum of 10% to 15% of the mirror surface. The first mirror and / or second mirror can be held particularly reliably and / or securely in a desired position. In some embodiments, the side guides each have at least one groove. Advantageously, the mirrors can therefore be arranged or installed in the holder quickly and with little effort.The mirrors can be inserted into the holder in such a way that insertion creates a held state.

[0045] Furthermore, the holder can have at least one positioning unit that is configured to define a preferred orientation and / or a preferred positioning of the holder during installation. In particular, the preferred orientation and / or preferred positioning can mean that the first mirror and / or the second mirror can be arranged in a predetermined arrangement and / or position according to their optical properties. For example, the optical properties of the first mirror and the second mirror can be different. The preferred orientation and / or preferred positioning can, for example, differentiate the optical properties of the first mirror and the second mirror. This simplifies installation and assembly and increases operating safety. In particular, the positioning unit can comprise elements that are provided asymmetrically on the holder.The positioning unit can be formed by at least one element, but also by two, three, or more elements. An element can be, for example, a projection, a protrusion, a material recess, and / or a hole in the holder. The positioning unit can also comprise several such elements.

[0046] According to some embodiments, the positioning unit has at least one receptacle for a positioning pin. This allows a positioning unit with low manufacturing tolerances and thus high accuracy and precision to be provided with little effort.

[0047] Furthermore, the mount can define a base on the first side. A beam combiner designed in this way is self-contained. This means that such a beam combiner can be moved at least almost arbitrarily and can, for example, be pushed and / or positioned into a beam path of illumination light. Furthermore, this allows the beam splitter to be assembled without the use of an assembly aid.

[0048] In addition, the first mirror and / or the second mirror can be partially transparent. This can mean that the first mirror and / or the second mirror transmits light in one or more wavelength ranges and reflects and / or absorbs light in at least one other wavelength range. This makes it possible, for example, to combine light with different wavelength ranges because certain mirrors can each reflect light to be coupled in and transmit light that has already been coupled in. In particular, it can be provided that the mirror reflects in a narrow spectral band but otherwise transmits. In other words, the mirror can be provided as a type of notch filter. The narrow spectral band can preferably be adapted to a light spectrum emitted by a light element assigned to a mirror.If illumination light from the associated light element hits the mirror, it is reflected, but illumination light with other wavelengths is transmitted. Mirrors can be provided, each of which can be assigned to a light element, with the light elements emitting illumination light in different spectral ranges. "Narrow spectral band" can mean a spectral width of at most 80 nm, in particular of at most 40 nm, or even of at most 20 nm.

[0049] The lighting elements can comprise single-color and / or narrow-band emitting LEDs (light-emitting diodes) and / or laser diodes. Furthermore, at least one of the lighting elements can be a white-light LED or another white-light source, or at least one broadband emitting lighting element. In some embodiments, the lighting unit comprises at least one blue lighting element, at least one red lighting element, at least one far-red lighting element, and at least one near-IR (near-infrared) lighting element, in particular LEDs or laser diodes. Additionally, the lighting unit can comprise at least one white-light LED or another white-light source.

[0050] In some embodiments, at least one of the mirrors comprises a coating, due to which the mirror is reflective for light of one wavelength range and transmissive for light of at least another wavelength range. Providing a coating is simple in terms of manufacturing technology and associated with low cost. Mirrors with different and / or coordinated optical properties can be manufactured in a short time. At least essentially the same starting products can be provided with a coating. This subsequently simplifies the processing of the mirrors and the installation of the mirrors in the holder. Furthermore, different mirrors then still exhibit essentially identical thermal expansion behavior.For example, if illuminating light with an angle of incidence at close range of 45° strikes a partially transmissive mirror that reflects light in a narrow spectral band, the illuminating light is reflected in the narrow spectral band according to the angle of incidence. The spectral range of the illuminating light, which essentially coincides with the narrow spectral band of the mirror, can thus be deflected by, for example, 90°. However, the remaining spectral range is at least largely transmitted. In particular, illuminating light from other lighting elements that emit light in a spectral range different from the narrow spectral band of the mirror is also at least largely transmitted.

[0051] In some embodiments, the lighting device comprises at least two lighting elements, wherein the beam combiner defines two different input sides, wherein the two lighting elements are each arranged on one of the input sides, and wherein the beam combiner is configured to couple light from the lighting elements into a common optical path. The lighting device can in particular comprise two, three, four, or five lighting elements.

[0052] The lighting unit may comprise lighting elements whose emission spectra together cover at least a spectral range from 450 nm to 850 nm.

[0053] The beam combiner may comprise at least three input sides, two of which are opposite each other and a third of which is opposite an output side. The output side may define the common optical path. The input sides and the output side may be different from the sides, in particular from the first side and the second side, of the beam combiner. In some embodiments, the three input sides and the output side form a rectangle and in particular a square. The first mirror and the second mirror may each lie on one of the diagonals of the rectangle or square. An angle of a close range of 45° may be provided between each of the first mirror plane and the second mirror plane and at least one of the input sides.

[0054] If two lighting elements are arranged opposite each other, a beam combiner can be provided in the optical path of the illumination light from the lighting elements. The beam combiner can, in particular, be arranged equidistantly between the two lighting elements. This can mean that the optical path from each of the lighting elements to a center point of the beam combiner, where, for example, the first mirror plane intersects the second mirror plane, is at least substantially the same.

[0055] The lighting elements can emit light in different spectral ranges. The beam combiner can comprise two partially transparent mirrors that reflect illumination light in a narrow spectral range, each adapted to the spectral range of one of the lighting elements. The mirrors each transmit at least largely the illumination light of the lighting element assigned to the other mirror. Furthermore, the beam combiner can be arranged such that the mirrors at least largely redirect illumination light in a narrow spectral range of the lighting element assigned to them by, for example, 90°. Furthermore, it can be provided that the mirrors redirect the illumination light in a common direction or to the same side, in particular to the output side, of the beam combiner.According to this example, illumination light would only be combined in the two narrow spectral ranges in which one of the two mirrors reflects illumination light, coupled into the common optical path and / or redirected from the opposite input sides to the output side of the beam combiner.

[0056] Furthermore, the lighting device can comprise a housing with a cover, wherein the cover has a recess in which the connector of the beam combiner is at least partially accommodated. Advantageously, the installation space can be kept small and / or the mechanical stability of the beam combiner can be increased when mounted and / or provided in the lighting device.

[0057] Furthermore, the connector can have play in the recess. The connector can have play with at least one surface of the recess. It can also be provided that the connector has play with at least one surface of the recess and is in contact with at least one surface of the recess. Operational safety and reliability can be increased as a result.

[0058] In addition, the recess can have a base, wherein in an assembled state the connector is arranged at a distance from the base. In particular, the base can be one of the surfaces of the recess. The distance can be, for example, 0.1 mm to 100 mm, in particular 0.5 mm to 50 mm, and preferably 1 mm to 10 mm. Direct contact of the connector with the base could limit the function of the beam combiner and / or lead to damage or even breakage of the beam combiner's mirrors. If a nominal distance is provided, larger manufacturing tolerances can be provided, for example, without these problems arising.

[0059] Furthermore, a deformable spacer can be arranged between the connector and the floor. In particular, the deformable spacer can have a damping function. For example, the deformable spacer can restrict the connector's mobility. Furthermore, the deformable spacer can prevent the connector from detaching from the beam combiner if, for example, shocks and / or vibrations affect the lighting device. In particular, the deformable spacer can exert a compressive force on the connector via the floor. This can, for example, compensate for manufacturing tolerances.

[0060] Furthermore, the illumination device may comprise a further beam combiner, wherein the beam combiner and the further beam combiner define a common optical path.

[0061] In some embodiments, the illumination device can comprise at least two beam combiners arranged optically one behind the other. If multiple beam splitters are present, they can be arranged such that an output side of a first beam splitter faces an input side of a second beam splitter. A lighting element, in particular a white light lighting element, can be arranged on the input side of a beam splitter furthest away from an optical light interface. The optical light interface can be configured to couple illumination light, in particular the illumination light of the common optical path, into an imaging device, for example an endoscope and / or exoscope. Using multiple beam combiners, spectral bands of the illumination light from multiple lighting elements can be combined.For each beam combiner, for example, the spectral range of the illumination light from at least two lighting elements can be coupled into the common optical path. In some embodiments, the connector of the beam combiner is formed integrally with the connector of the additional beam combiner. This further increases the compactness of the lighting device. Furthermore, the mechanical stability and reliability of the beam combiner and the additional beam combiner can be increased. The installation of both connectors can also be combined in a single step.

[0062] Finally, it can be provided that the beam combiner and / or the further beam combiner at least almost completely fills a cavity of the housing, in particular when the housing is equipped with the lighting elements. In particular, the cavity is a space between the lighting elements of the beam combiner. The beam combiner and / or the further beam combiner can be provided for use or for coupling illumination light into a common optical path in the cavity. A particularly efficient beam combiner and / or a particularly efficient illumination device can be provided if almost all of the illumination light emitted by at least one of the lighting elements passes through at least the first mirror or second mirror of one of the beam combiners. This can minimize light losses and / or increase accuracy.

[0063] The illumination device according to the invention can be part of a medical system and / or part of an imaging device. An imaging device can be, for example, an endoscopic imaging device, specifically an endoscope device. Alternatively, the imaging device could be an exoscopic, a microscopic, or a macroscopic imaging device. In particular, the imaging device can be a medical imaging device. The imaging device can be provided, for example, for examining a cavity.

[0064] The present invention is described below by way of example with reference to the attached figures. The drawings, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and use them sensibly in combination within the scope of the claims. If there is more than one example of a particular object, only one of them will be provided with a reference symbol in the figures and the description. The description of this example can be applied accordingly to the other examples of the object. If objects are named in particular using numerical words such as first, second, third object etc., these serve to name and / or assign objects. Accordingly, for example, a first object and a third object may be included, but not a second object.However, using number words, it might also be possible to derive a number and / or order of objects.

[0065] They show:

[0066] Fig. 1 is a schematic representation of an imaging device with an illumination device;

[0067] Fig. 2 is a schematic representation of the lighting device;

[0068] Fig. 3 schematic transmission curves of mirrors of the lighting device;

[0069] Fig. 4 is a schematic perspective view of another embodiment of the imaging device;

[0070] Fig. 5 is a perspective view of a beam combiner;

[0071] Fig. 6 is a schematic plan view of the beam combiner;

[0072] Fig. 7 is a schematic representation in a plan view of the

[0073] Lighting device 12 with two beam combiners;

[0074] Fig. 8 is a perspective view of another embodiment of a beam combiner;

[0075] Fig. 9 is a perspective view of another embodiment of a beam combiner; Fig. 10 is a top view of the lighting device including a housing and a cover;

[0076] Fig. 11 is a side view of the lighting device including the housing and the cover;

[0077] Fig. 12 is a plan view of another embodiment of a lighting device including a housing and a cover;

[0078] Fig. 13 is a side view of the further embodiment of a lighting device including the housing and the cover;

[0079] Fig. 14 Top view of the cover of the lighting device;

[0080] Fig. 15 Top view of the lid of the further embodiment of the

[0081] lighting device;

[0082] Fig. 16 further embodiment of a beam combiner; and

[0083] Fig. 17 further embodiment of a beam combiner.

[0084] Fig. 1 shows a schematic representation of an imaging device 10. In the exemplary case shown, the imaging device 10 is an endoscopic imaging device, specifically an endoscope device. Alternatively, the imaging device 10 could be an exoscopic, a microscopic, or a macroscopic imaging device. The imaging device 10 is shown as an example of a medical imaging device. The imaging device 10 is intended, for example, for examining a cavity.

[0085] The imaging device 10 comprises a medical imaging device 14. In the illustrated case, this is an endoscope.

[0086] The imaging device 10 further comprises an illumination device 12 with an optical interface 16. The imaging device 14 can be optically connected to the optical interface 16. The optical interface 16 can be part of an optical-mechanical interface that can be selectively connected and detachable. The illumination device 14 can be selectively decoupled from the illumination device 12. The illumination device 12 is configured to supply illumination light to the optical interface 16. During imaging using the imaging device 14, the illumination device 12 can accordingly provide the required illumination light, which is guided to the illumination device 14 and from there coupled out onto an object to be imaged, such as a site.

[0087] In the illustrated case, the imaging device 10 further comprises a display unit on which images based on image data acquired by the imaging device 14 can be displayed. These may be video images, still images, overlays of different images, partial images, image sequences, etc.

[0088] The imaging device 10 is multimodal. By way of example, the imaging device can be operated in three basic modes: a multispectral mode, a fluorescence mode, and a white light mode. Furthermore, it can be provided that the imaging device 10 can be operated in a hyperspectral mode in addition to or alternatively to the multispectral mode.

[0089] The illumination device 12 is multimodal. The illumination device 12 can be operated in different illumination modes, in which it provides light for different imaging modes. In the present case, the illumination device 12 can be operated in three basic modes: a multispectral mode, a fluorescence mode, and a white light mode. Likewise, the imaging device 14 can be operated in different operating modes, specifically also in at least one multispectral mode, one fluorescence mode, and one white light mode. In the corresponding operating mode of the imaging device 10, the modes of the illumination device 12 are coordinated with one another.

[0090] Fig. 2 shows a schematic representation of the lighting device 12. The lighting device 12 comprises a plurality of independently activatable lighting elements 20, 22, 24, 26, 28. These are configured to emit light according to different emission spectra in order to provide illumination light, ie the respective emission spectrum differs from lighting element to lighting element.

[0091] For example, the light elements 20, 22, 24, 26, 28 are embodied as LEDs. Specifically, a first light element 20 is embodied as a red LED, a second light element 22 as a dark-red LED, a third light element 24 as a blue LED, and a fourth light element 26 as a near-IR LED. The colored light elements 20, 22, 24, 26 each emit in a narrowband, for example, with emission peaks at wavelengths of approximately 660 nm (first light element 20), 770 nm (second light element 22), 460 nm (third light element 24), and 940 nm (fourth light element 26).

[0092] Furthermore, a fifth luminous element 28 is provided, which in this case is a white light luminous element, such as a white light LED. The fifth luminous element 28 emits, for example, in a spectral range of approximately 400 to 700 nm. In other embodiments, laser diodes can also be used, in particular as colored luminous elements.

[0093] Alternatively, a lighting element can be provided as the fifth lighting element 28 which emits illumination light in a part of the spectral range from 400 nm to 700 nm, in particular in a narrow-band part of the spectral range.

[0094] Depending on the lighting mode, some of the lighting elements 20, 22, 24, 26, 28 are activated at least temporarily, whereas other lighting elements 20, 22, 24, 26, 28 may not be used in the lighting mode in question.

[0095] In the present case, a first group comprises the first light element 20 and the fourth light element 26. The first group can additionally comprise the light element 22 and / or the light element 24. The first group is used for multispectral imaging, wherein the included light elements 20, 26 and optionally 22 and 24 each serve as a support point. In multispectral mode, for example, the first light element 20 is first illuminated and an image is recorded. The fourth light element 26 is then illuminated and an image is recorded. The images are each based on remission, i.e. the light scattered back from the object to be imaged is observed. The two different support points can be used to obtain spectral information about the object to be imaged. For example, this can be used to assess certain tissue types, a perfusion state, a tissue texture or the like.

[0096] Furthermore, a second group comprises the first light-emitting element 20, the second light-emitting element 22, and the third light-emitting element 24. The second group is used for illumination in fluorescence imaging. For example, objects colored with suitably selected dyes can be specifically viewed here. Different dyes can also be introduced into different types of tissue or the like, which are then viewed simultaneously. By specifically exciting a specific dye, it is excited to fluoresce. The fluorescent light is then imaged. The first light-emitting element 20 is suitable, for example, for exciting the dye cyanine 5.5 (Cy 5.5). The second light-emitting element 22 is suitable for exciting the dye indocyanine green (ICG). The third light-emitting element 24 is suitable for exciting the dye fluorescein.

[0097] Furthermore, a third group comprises the fifth luminous element 28. In the present embodiment, the third group also comprises the first luminous element 20 and the third luminous element 24. The third group serves to provide illumination light for white light imaging. For this purpose, white light from the fifth luminous element 28 can be mixed with light from certain colored luminous elements, thereby compensating for spectral losses and / or allowing a color temperature to be specifically adjusted.

[0098] It can be seen that some of the lighting elements 20, 22, 24, 26, 28 are assigned to several groups, for example the first lighting element 20 to all three groups and the third lighting element 24 and possibly also the second lighting element 22 to the second and third groups.

[0099] Alternatively or additionally, it can also be provided that some or all of the light elements 20, 22, 24, 26, 28 are used in a hyperspectral mode. This generates a broad excitation spectrum. In combination with a suitable hyperspectral detector, spectral information relating to the object to be imaged can then be acquired across the entire visible and near-IR spectrum. For this purpose, the imaging device 14 can comprise a pushbroom arrangement as a hyperspectral detector. In other embodiments, a whiskbroom arrangement, a staring arrangement and / or a snapshot arrangement is used. The imaging device 14 can be a hyperspectral imaging device. With regard to different methods of hyperspectral imaging and the components required therefor, reference is made to the specialist article “Review of spectral imaging technology in biomedical engineering: achievements and challenges” by Quingli Li et al.Published in Journal of Biomedical Optics 18(10), 100901 , October 2013, as well as reference to the specialist article "Medical hyperspectral imaging: a review" by Guolan Lu and Baowei Fei, published in Journal of Biomedical Optics 19(1), 010901 , January 2014. The illumination device 12 comprises two beam combiners 30, 32. The function of the beam combiners 30, 32 is generally described in connection with Figures 1 to 4. Embodiments of the beam combiners are described in more detail in subsequent figures. It is understood that the beam combiners 30, 32 can be replaced by the beam combiners described below. The beam combiners 30, 32 each comprise an output side 42, 44, an input side 37, 41 opposite the output side 42, 44, and two input sides 34, 36, 38, 40 opposite each other.All input sides 34, 36, 37, 38, 40, 41 guide incident illumination light at least partially to the corresponding output side 42, 44. The output side 42 of a first beam combiner 30 faces an input side 41 of the second beam combiner 32. The output side 44 of the second beam combiner 32 faces the optical interface 16. The two beam combiners 30, 32 are preferably arranged coaxially with each other and / or with the optical interface.

[0100] The lighting device 12 can comprise suitable optical elements such as lenses and / or mirrors (not shown). Several lenses 78, 80, 82, 84, 86, 88 are shown as examples in Fig. 2. A lens 78 is assigned, for example, to the optical interface 16 and couples light coming from the output side 44 of the second beam combiner 32 into the optical interface 16. Furthermore, a lens 80, 82, 84, 86, 88 can be assigned to each of the lighting elements 20, 22, 24, 26, 28. A particularly high degree of compactness can be achieved in particular if the lighting elements 20, 22, 24, 26, 28 are each arranged on the input sides 34, 36, 37, 38, 40 of the at least one beam combiner 30, 32 without an intermediate mirror. The lighting elements 20, 22, 24, 26, 28 can then be moved very close to at least one crossed beam splitter 30, 32.

[0101] The beam combiners 30, 32 each comprise two mirrors 90, 92, 94, 96. These can generally be partially transparent, so that illumination light from all input sides 34, 36, 37, 38, 40, 41 is redirected to the respective output side 42, 44. In the present embodiment, the mirrors 90, 92, 94, 96 are selectively transparent. This is illustrated with further reference to Fig. 3. The mirrors 90, 92, 94, 96 can be filters that reflect only in a defined area but otherwise have high transmission. Fig. 3 shows transmission curves 98, 100, 102, 104 of the mirrors 90, 92, 94, 96 of the two beam combiners 30, 32. Each of the colored light elements 20, 22, 24, 26 or each of the opposite input sides 34, 36, 38, 40 is assigned one of the mirrors 90, 92, 94, 96.The mirrors 90, 92, 94, 96 are selected such that they each reflect in the wavelength range in which the associated light element 20, 22, 24, 26 emits, but also largely transmit. For this purpose, notch filters can be used in the mid-wavelength range, which can, for example, have the transmission spectra 100 and 102. At spectral edges, high-pass or low-pass filters can also be used instead of notch filters; see transmission spectra 98 and 104.

[0102] Due to the specific transmission spectra 98, 100, 102, 104 of the beam combiners 30, 32, the illumination light of the fifth light element 28 is spectrally clipped. It may therefore be expedient to specifically supplement the illumination light blocked by the beam combiners 30, 32 using the light elements 20 and 24, optionally also 22 and / or 26. This allows illumination light to be supplemented specifically in those spectral ranges in which the beam combiners 30, 32 absorb and / or reflect illumination light of the fifth light element 28, but in any case does not transmit it to the optical interface 16. The additionally used light elements 20, 24 and optionally 22 are preferably operated with reduced power or with adjusted power. The aim here can be to at least largely restore the original spectrum of the fifth light element 28.

[0103] In some embodiments, the fifth light-emitting element 28 can alternatively be a green light-emitting element, or more generally, a colored light-emitting element that primarily emits in the spectral range transmitted by the at least one beam combiner 30, 32. For example, in such embodiments, the fifth light-emitting element 26 can be an LED with an emission peak at approximately 530 nm. A green laser diode is also suitable for this purpose. In this case, it can be provided that color mixing occurs in white light mode and, in particular, no individual white light source such as a white light LED is used, but rather white light from separate light elements is specifically mixed.

[0104] It is understood that, with suitable dyes, such a green luminous element can also be used in fluorescence mode. Alternatively or additionally, it could be used in multispectral mode. The illumination device 12 defines a common optical path 54 into which emitted light from the luminous elements 20, 22, 24, 26, 28 can be coupled. The common optical path 54 extends from the output side 44 of the second beam combiner 32 to the optical interface 16. In this case, the common optical path 54 is arranged coaxially with the fifth luminous element 26.

[0105] In the embodiment shown, the lighting elements 20, 26 of the first group are arranged such that the illumination light emitted by the lighting elements 20, 26 travels a light path of at least substantially equal length from the respective lighting element 20, 26 to the optical interface 16. The lighting elements 20, 26 of the first group each have a light-emitting surface 56, 58. The light-emitting surfaces 56, 62 are arranged equidistantly with respect to the common optical path 54. This is achieved in the present case by arranging the two lighting elements 20, 26 at the same distance from their associated beam combiner 32 (here, for example, the second beam combiner 32), specifically from its opposite input sides 38, 40. The light is coupled into the common optical path 54 by the beam combiner 32.

[0106] The beam combiners 30, 32 are arranged in particular such that light-emitting surfaces 56, 58, 60, 62, 64 of the lighting elements 20, 22, 24, 26, 28 are each arranged equidistantly with respect to their associated beam combiner 30, 32.

[0107] By using beam combiners 30, 32 and lighting elements 20, 22, 24, 26, 28 that can be used jointly for different modes, the illumination device 12 exhibits a high degree of compactness. Furthermore, the equidistant arrangement ensures that no spectral shifts occur when the imaging device 14 or its light guide is rotated relative to the optical interface 16.

[0108] It is understood that a different number of lighting elements 20, 22, 24, 26, 28 and / or a different number of beam combiners 30, 32 may be used.

[0109] Fig. 4 shows a schematic perspective view of another

[0110] Embodiment of an imaging device 10'. The reference numerals of this

[0111] The embodiments are marked with apostrophes for differentiation. In this embodiment, the imaging device 10' is designed as an exoscopic imaging device. It comprises an illumination device 12' and an imaging device 14'. Their basic functionality corresponds to that described above, but in this embodiment, the imaging device 14' is designed as an exoscope.

[0112] Embodiments of beam combiners are described in more detail below. These can fundamentally have the same functionality, at least with regard to the light deflection of the beam combiners 30, 32, and can therefore be provided in the lighting device 12, 12' instead.

[0113] Referring to Fig. 5 and Fig. 6, an embodiment of a beam combiner 200 will now be described in more detail. Fig. 5 shows a beam combiner 200 comprising a first mirror 202, a second mirror 210, a holder 218, and a connector 222. The first mirror 202 in turn comprises a first section 204 and a second section 206, which together define a first mirror plane 208 (see also Fig. 6). The second mirror 210 comprises a third section 212 and a fourth section 214, which together define a second mirror plane 216 (see also Fig. 6). The first mirror 202 and the second mirror 210 are partially transmissive in the manner already described. In the exemplary embodiment shown, this is achieved in particular in that the first mirror 202 and the second mirror 210 comprise a coating.

[0114] The first mirror 202 and the second mirror 210 extend in a horizontal direction and in a vertical direction. The respective edges of the mirrors 202, 210 define one side of the beam combiner 200, wherein the edges of the mirrors 202, 210 together define one side of the beam combiner 200 in the vertical direction. In the illustrated case, the lower edges 219 of the first mirror 202 and the second mirror 210 define a first side 220 of the beam combiner 200. Opposite the first side 220, a second side 224 is defined by the upper edges 221 of the mirrors 202, 210. The first mirror 202 and the second mirror 210 define further opposite sides 238a, 238b in the horizontal direction, which are different from the first side 220 and the second side 224. It is understood that the first mirror 202 and the second mirror 210 each define opposite sides 238a, 238b.

[0115] As can be seen in Fig. 6, the second mirror 210 is formed in one piece. The first mirror 202, on the other hand, is formed in two parts, with the first section 204 and the second section 206 each defining a part of the first mirror 202. The first section 204 and the second section 206 are spaced apart from each other and arranged on opposite sides of the second mirror plane 216, at least partially in contact with the second mirror 210.

[0116] Furthermore, it can be seen that the first mirror plane 208 and the second mirror plane 216 are arranged parallel to one another in a spatial direction of extension and at right angles to one another in a further direction of extension perpendicular thereto. It is not absolutely necessary for the first mirror plane 208 and the second mirror plane 216 to be arranged exactly at right angles to one another in the further direction of extension. On the one hand, minor deviations, for example in a range of up to 10°, from the perpendicularity can be tolerated due to, for example, manufacturing tolerances. On the other hand, in embodiments not shown in detail, it can be advantageous to provide a cross-shaped arrangement of the first mirror plane 208 and the second mirror plane 216 with any angle between 1° and 90°. A crossing angle can be suitably selected depending on the arrangement and design of the lighting elements used.

[0117] The mount 218 has a base 234 whose configuration mimics the arrangement of the first mirror 202 and the second mirror 210. That is, the base 234 extends substantially along the first mirror 202 and the second mirror 210. Furthermore, it can be seen that the base 234 extends beyond the horizontal ends of the first mirror 202 and the second mirror 210. Furthermore, the mount 218 defines a base 246 on the first side 220. The beam combiner 200 extends vertically from the base 246 and / or is supported by the base 246.

[0118] The holder 218 also includes a positioning unit 242, comprising three receptacles 244 for positioning pins 245, which are shown, for example, in Fig. 11. The receptacles 244 are arranged asymmetrically to ensure installation of the beam combiner 200 in a preferred orientation and / or a preferred positioning.

[0119] The holder 218 includes a groove 230 and another groove 232, each of which has at least substantially the same horizontal extent as the mirrors 202, 210. Furthermore, the groove 230 and the groove 232 are provided continuously along the horizontal extent of the mirrors 202, 210. Furthermore, the groove 230 intersects the groove 232. The groove 230 accommodates the first section 204 and the second section 206, and the groove 232 accommodates the third section 212 and the fourth section 214.

[0120] Furthermore, the holder 218 comprises side guides 236, which are configured to hold the first mirror 202 and the second mirror 210 laterally. This holding is achieved in particular by grooves 240 being provided on the side guides 236. The mirrors 202, 210 are partially received in the horizontal direction by the grooves 240. The side guides 236 are provided on the two opposite sides 238a, 238b and / or hold the first mirror 202 and the second mirror 210 on the two opposite sides 238a, 238b. The mirrors 202, 210 also have play in the side guides 236. This is particularly advantageous in order to allow the mirrors 202, 210 space for spatial expansion. This may be necessary, for example, if the mirrors 202, 210 heat up or expand during operation.

[0121] The connector 222 is arranged on the second side 224 of the beam combiner 200. The connector 222 is jointly supported by the first mirror 202 and the second mirror 210. In the exemplary embodiment shown here, the connector 222 is made in one piece and is made of plastic. In other embodiments, the connector is made of rubber, for example, to influence a damping function of the connector. In particular, it can be seen in Fig. 6 that the connector 222 basically has a square basic shape, with the corners being chamfered. The basic shape of the connector 222 is indicated in Fig. 6 by a dotted line. The corners of the connector 222 are chamfered in such a way that a regular octagon is formed. This means that the side edges of the connector are at least substantially the same length.The connector 222 extends over approximately one-third of the horizontal extent of the first mirror 202 and the second mirror 210, wherein the connector 222 is provided at least substantially centrally on the beam combiner 200. By central, it is meant in particular that a center point of the connector 222 lies at least substantially at a center point of the beam combiner 200. Fig. 10 shows a further embodiment of a connector 222' with rounded corners. Furthermore, the connector 222, 222' has a damping function. Referring again to Fig. 5 and Fig. 6, it can be seen that the connector 222 comprises a groove 226 in which the first section 204 and the second section 206 are partially received, and a further groove 228 in which the third section 212 and the fourth section 214 are partially received. The groove 226 crosses the further groove 228.On the one hand, the connector mechanically couples the first section 204 and the second section 206 at the second side 224 such that the first section 204 and the second section 206 are immobile relative to each other at the second side 224. On the other hand, the connector is configured to at least limit movements of the first section 204 and the second section 206 parallel to the second mirror plane 216.

[0122] The beam combiner 200 defines an output side 249, two different input sides 250a, 250b, and another input side 251. The two different input sides 250a, 250b are opposite each other, and the output side 249 is opposite the other input side 251. A common optical path 54 exits the output side 249. The side edges of the basic shape of the connector 222 are each arranged parallel to one of the input sides 250a, 250b, 251 and / or the output side 249. The base surface 234 of the holder 218 forms a central section that is substantially square. The side edges of the central square portion of the base 234 are arranged parallel to the side edges of the connector 222 and thus also parallel to one of the input sides 250a, 250b, 251 and / or the output side 249.The central square portion of the base 234 has a larger area in a horizontal plane than the connector 222. In other words, the side edges of the connector 222 have an extension that corresponds, for example, to 70% to 90% of an extension of the side edges of the central square portion of the base 234.

[0123] The beam combiner 200 is configured to couple light from luminous elements 248, which are shown, for example, in Fig. 7, into the common optical path 54. The input sides 250a, 250b, 251 and the output side 249 each form an angle of 45° with one of the mirror planes 208, 216.

[0124] Fig. 7 shows the beam combiner 200 installed, by way of example, in a lighting device 12 shown without a housing. A lighting element 248 is arranged on each of the two different input sides 250a, 250b. The input sides 250a, 250b are located opposite one another. Illumination light from the lighting elements 248 is coupled into the common optical path 54 by the beam combiner 200. The common optical path 54 exits the beam combiner 200 from the output side 249. An output side 249 of a further beam combiner 262 is arranged facing the further input side 251 of the beam combiner 200. The further beam combiner 262 is essentially structurally identical to the beam combiner 200, which is why the same reference numerals are used for features of the further beam combiner 262. The difference between the beam combiner 200 and the further beam combiner 262 are the optical properties of the mirrors 202, 210.It is understood that a further beam combiner 262 does not necessarily have to be provided. Furthermore, more than two beam combiners 200, for example three or four beam combiners 200, can also be provided. This allows light from a smaller or larger number of lighting elements to be combined. Lighting elements 248 are also arranged on two different input sides 250a, 250b of the further beam combiner 262. Illumination light from these lighting elements 248 is redirected by the beam combiner 226 such that it exits the output side 249 of the further beam combiner 262 and enters the further input side 251 of the beam combiner 200. The illumination light is thus coupled into the common optical path 54. Furthermore, a further lighting element 248 is arranged on the further input side 251 of the further beam combiner 262.Illumination light from the luminous element 248 at the further input side 251 of the further beam combiner 262 is emitted substantially coaxially with the common optical path 54. In the manner already described, illumination light in at least one spectral band of this luminous element 248 can be at least partially deflected by at least one of the beam combiners 200, 262 and thereby coupled out of the common optical path 54. This at least one spectral band can be emitted at least substantially by one of the other luminous elements 248 and coupled into the common optical path 54 by at least one of the beam combiners 200, 248.

[0125] Fig. 8 shows a further embodiment of a beam combiner 200", which is similar to the beam combiner 200. In contrast to the beam combiner 200, however, a different connector 222" is provided. The holder 218 has at least substantially the same features. The connector 222" is largely or completely identical in construction to the holder 218 of the beam combiner 200" and is placed on the second side 224 of the beam combiner 200". It can be seen that in the exemplary embodiment shown, the side holders 236 of the holder 218 are not in contact with the side holders 236" of the connector 222". This is achieved by the side holders 236, 236" having a correspondingly coordinated vertical extension. Fig. 9 shows yet another embodiment of a beam combiner 200'", wherein again a holder 218 similar to the holder 218 of the beam combiner 200 is provided.The connector 222'" is arranged on the second side 224 of the beam combiner 200'". In addition, the connector 222'" comprises a slot 266 configured to at least partially receive the first mirror 202, and another slot 268 configured to at least partially receive the second mirror 210. The mirrors 202, 210 are at least vertically movable in the slots 266, 268. In particular, the mirrors 202, 210 can protrude vertically upwards and downwards from the slots 266, 268. The connector 222'" comprises four side guides 236'" similar to the side guides 236, which are configured to laterally hold the mirrors 202, 210. In an installed state of the connector 222'", each of the side guides 236" is supported by a respective side guide 236 of the holder 218. The mirrors 202, 210 have play in the side guides 236'" and in slots 266, 268.The embodiment shown here is particularly advantageous because it ensures a high degree of mechanical stability. The play also provides space into which the mirrors 202, 210 can extend in the event of thermal expansion. In the vertical direction, the slots 266, 268 allow almost unlimited mobility of the mirrors. A further advantage of this embodiment is that the connector 222'" can be formed integrally with the holder 218 and / or at least as a pre-assembled component. In this case, the mirrors 202, 210 can be pushed through the slots 266, 268 into the holder 218 together with the connector 222'". It is understood that at least one of the mirrors 202, 210 can be formed in at least two parts and / or one of the mirrors 202, 210 can be formed in one piece.

[0126] Fig. 10 shows the illumination device 12 in a plan view, wherein the illumination device 12 comprises a housing 252 with a cover 254. Fig. 11 shows a side sectional view of the illumination device 12. As already described at least in connection with Fig. 7, the illumination device 12 comprises a beam splitter 200 and a further beam splitter 262. Furthermore, the illumination device 12 comprises five lighting elements 248. The illumination light of the five lighting elements 248 is coupled by the beam splitters 200, 262 into a common optical path 54 (not shown), which exits from the output side 249 of the beam combiner 200. Subsequently, the illumination light of the common optical path 54 is coupled into an optical interface 16. The optical interface 16 is configured so that an imaging device (not shown here) can be coupled thereto.A cavity 264 is provided in the housing 252, which is vertically delimited at the top by the cover 254. The cavity 264 is at least substantially filled by the beam combiners 200, 262. This allows a high degree of compactness to be achieved. In addition, almost all of the illumination light from each of the lighting elements 248 passes through one of the beam combiners 200, 262. Intensity losses due to light paths running laterally past the beam combiners 200, 262 can be reduced. Fig. 11 shows two recesses 256 in the cover 254. The connectors 222' are each partially received in one of the recesses 256. It can also be seen that the connectors 222' have lateral play in the recesses 256. The recesses 256 each have a bottom 258. The bottom 258 is the vertically upper surface of the recess 256 of the cover in an installed state.The connectors 222' are each spaced apart from the bases 258. The resulting space is at least substantially filled by a deformable spacer 260 each. This means that the deformable spacers 260 are arranged between the bases 258 and the connectors 222'. In the installed state of the cover 254, the deformable spacers 260 are compressed in the vertical direction and / or a compressive force is exerted on the connectors 222' via the bases by means of the spacers 260.

[0127] Furthermore, Fig. 11 shows the positioning pins 245, by means of which the beam combiners 200, 262 can be installed in a preferred orientation and / or a preferred positioning of the holder 218.

[0128] Fig. 12 shows a further embodiment of a lighting device 12"" in a plan view, wherein the lighting device 12"" comprises a housing 252 with a cover 254"". Fig. 13 shows a side sectional view of the lighting device 12"". The lighting device 12"" differs essentially from the lighting device 12 in the formation of the recess 256"", which is determined by the shape of the connector 222"". Further features of the lighting device 12"" can be the same as the features of the lighting device 12 already described. The lighting device 12"" provides only one connector 222"", wherein the connector 222"" is formed in one piece. The connector 222"" serves as a connector for the beam combiner 200"" and the beam combiner 262"". With respect to some features, such as the grooves 226, 228, the choice of material and the damping properties, the connector 222"" may be the same as the connector 222.The connector 222"" is supported by the mirrors 202, 210 of both beam combiners 200"" and 262"".

[0129] Fig. 14 and Fig. 15 each show an embodiment of the cover 254, or 254"", corresponding to Figs. 10 and 11, and Figs. 12 and 13, respectively. While the cover 254 has two recesses 256, namely one for each beam combiner 200, 262, the cover 254"" has only one recess 256"" for both beam combiners 200", 262". All recesses have a bottom 258, 258"", wherein the connectors 222, 222"" can be arranged at a distance from the bottom 258, 258"".

[0130] Fig. 16 and Fig. 17 show yet another embodiment of a beam combiner. The first digit of the reference numerals is increased by one to emphasize the similarity to the previously shown beam combiners. Essentially, the beam combiners of Figs. 16 and 17 can have the same features as the previously shown embodiments of beam combiners 200. The description of the figures is therefore limited to the description of differences from the previous beam combiners 200.

[0131] Fig. 16 shows only a first mirror 302 and a second mirror 310 of a beam combiner 300 in an unassembled state. It is understood that the mirrors 302, 310 can be provided in a holder 218 shown in the previous figures. The first mirror 302 and the second mirror 310 of the beam combiner 300 are each formed integrally. Furthermore, it can be seen that a connector 322 is formed integrally with a first portion 304 and a second portion 306 of the first mirror 302. The first portion 304 and the second portion 306 are spaced apart from each other by the connector 322 and a slot 270. The slot 270 has substantially the same width as the connector 322 and is formed centrally on the first mirror 302. In addition, in the present case, the slot extends over approximately 50% of the height of the first mirror 302. A slot 272 is also formed centrally on the second mirror 310.The slot 272 has at least substantially the same width and height as the connector 322. In an assembled state, the mirrors 302, 310 are inserted into one another so that they are arranged in a cross shape. For this purpose, the slot 272 is pushed onto the connector 322. Compared to the arrangement in Fig. 16, one of the mirrors 302, 310 is rotated, for example by 90 degrees, in order to achieve a cross-shaped arrangement. The mirrors 302, 310 are at least substantially flush on a first side 320 and the opposite side. It is understood that in other embodiments the slots can be of different lengths, in particular coordinated with an extension of the connector of the respective other mirror. Fig. 17 shows a beam combiner 400, wherein a first mirror 402 and a second mirror 410 are each formed in two parts.A first section 404 and a second section 406 of the first mirror 402 are spaced apart from each other by a connector 422. A third section 412 and a fourth section 414 of the second mirror 410 are also spaced apart from each other by the connector 422. The connector 422 extends along a vertical axis of the mirrors 402, 410 within a first mirror plane 408 and a second mirror plane 416. It can also be seen that the connector 422 is arranged centrally of the beam combiner 400 and holds the mirrors 402, 410 at inner edges of the respective two parts of the mirrors 402, 410. The connector 422 comprises, for example, grooves 274 that at least partially accommodate the first mirror 402 and the second mirror 410. Furthermore, the mirrors are arranged in a holder 418. The holder 418 is at least substantially identical to a holder 218 already described.

[0132] List of reference symbols

[0133] 10 Imaging device

[0134] 12 Lighting device

[0135] 14 Imaging device

[0136] 16 optical interface

[0137] 20 light elements

[0138] 22 light elements

[0139] 24 light elements

[0140] 26 lighting elements

[0141] 28 light elements

[0142] 30 beam combiners

[0143] 32 beam combiners

[0144] 34 Entrance page

[0145] 36 Entrance page

[0146] 37 Entrance page

[0147] 38 Entrance page

[0148] 40 Entrance page

[0149] 41 Entrance page

[0150] 42 Exit page

[0151] 44 Exit page

[0152] 54 common optical path

[0153] 56 light-emitting surface

[0154] 58 light-emitting surface

[0155] 60 light-emitting surface

[0156] 62 light-emitting surface

[0157] 64 light-emitting surface

[0158] 74 display unit

[0159] 78 lens

[0160] 80 lens

[0161] 82 lens

[0162] 84 lens

[0163] 86 lens

[0164] 88 lens

[0165] 90 mirrors

[0166] 92 mirrors

[0167] 94 Mirrors 96 Mirrors

[0168] 98 Transmission spectrum

[0169] 100 transmission spectrum

[0170] 102 Transmission spectrum

[0171] 104 Transmission spectrum

[0172] 200 beam combiners

[0173] 202 first mirror

[0174] 204 first section

[0175] 206 second section

[0176] 208 first mirror plane

[0177] 210 second mirror

[0178] 212 third section

[0179] 214 fourth section

[0180] 216 second mirror plane

[0181] 218 bracket

[0182] 219 bottom edge

[0183] 220 first page

[0184] 222 connectors

[0185] 221 top edge

[0186] 224 second page

[0187] 226 groove

[0188] 228 additional grooves

[0189] 230 groove

[0190] 232 additional grooves

[0191] 234 floor space

[0192] 236 side guides

[0193] 238 facing pages

[0194] 240 groove

[0195] 242 Positioning unit

[0196] 244 recording

[0197] 245 Positioning pin

[0198] 246 stand space

[0199] 248 lighting elements

[0200] 249 Exit page

[0201] 250 introductory pages

[0202] 251 additional entry page

[0203] 252 housings

[0204] 254 Cover 256 Recess

[0205] 258 floor

[0206] 260 deformable spacers

[0207] 262 additional beam combiner 264 cavity

[0208] 266 slot

[0209] 268 additional slot

[0210] 270 slot

[0211] 272 Slot 274 Groove

Claims

Claims 1. A beam combiner (200), comprising: a first mirror (202) comprising a first portion (204) and a second portion (206) that together define a first mirror plane (208), and a second mirror (210) comprising a third portion (212) and a fourth portion (214) that together define a second mirror plane (216), wherein the first mirror plane (208) and the second mirror plane (216) are arranged in a cross shape, wherein the first portion (204) and the second portion (206) are spaced from each other and arranged on opposite sides of the second mirror plane (216); a holder (218) that holds the first portion (204) and the second portion (206) on a first side (220);and a connector (222) mechanically coupling the first portion (204) and second portion (206) on a second side (224) different from the first side (220) such that the first portion (204) and the second portion (206) are immovable relative to each other on the second side (224); 2. Beam combiner (200) according to claim 1, wherein the second side (224) is opposite the first side (220).

3. Beam combiner (200) according to claim 1 or 2, wherein the second mirror (204) is one piece.

4. Beam combiner (200) according to one of the preceding claims, wherein the connector (222) comprises at least one groove (226) in which the first portion (204) and / or the second portion (206) is at least partially received.

5. Beam combiner (200) according to one of the preceding claims, wherein the connector (222) comprises at least one further groove (228) in which the third section (212) and / or the fourth section (214) is at least partially received. REVISED SHEET (RULE 91) ISA / EP 6. Beam combiner (200) according to claim 4 and 5, wherein the at least one groove (226) of the connector (222) crosses the at least one further groove (228) of the connector (222).

7. Beam combiner (200) according to one of the preceding claims, wherein the connector (222) is arranged to transmit movements of the first Section (204) and / or the second section (206) parallel to the second mirror plane (216).

8. Beam combiner (200) according to one of the preceding claims, wherein the connector (222) is formed in one piece.

9. Beam combiner (200) according to one of the preceding claims, wherein the connector (222) has a rectangular, in particular square, basic shape.

10. Beam combiner (200) according to one of the preceding claims, wherein the connector (222) has beveled and / or rounded corners. 1 1. Beam combiner (200) according to one of the preceding claims, wherein the connector (222) is made of plastic and / or rubber.

12. Beam combiner (200) according to one of the preceding claims, wherein the connector (222) has a damping function.

13. Beam combiner (200) according to one of the preceding claims, wherein the first mirror (202) and the second mirror (210) together Wear connectors (222).

14. The beam combiner (200) of any one of claims 1 to 10, wherein the connector (222) is integrally formed with the first portion (204) and the second portion (206).

15. Beam combiner (200) according to one of the preceding claims, wherein the holder (218) comprises at least one groove (230) in which the first section (204) and / or the second section (206) is at least partially received.

16. Beam combiner (200) according to one of the preceding claims, wherein the holder (218) comprises at least one further groove (232) in which the third section (212) and / or the fourth section (214) is at least partially received.

17. Beam combiner (200) according to claim 15 and 16, wherein the at least one groove (230) of the holder (218) crosses the at least one further groove (232) of the holder (218).

18. Beam combiner (200) according to one of the preceding claims, wherein the holder (218) has a cross-shaped base (234).

19. Beam combiner (200) according to one of the preceding claims, wherein the holder (218) has a length and a width, and wherein the first mirror (202) and the second mirror (210) have an extension which corresponds to at least 80%, preferably at least 90% and particularly preferably at least 95% of the length and / or the width.

20. Beam combiner (200) according to one of the preceding claims, wherein the holder (218) comprises side guides (236) which are adapted to hold the first mirror (202) and / or the second mirror (210) laterally.

21. Beam combiner (200) according to claim 20, wherein the mirrors (202, 210) have play in the side guides (236).

22. Beam combiner (200) according to claim 20 or 21, wherein the side guides (236) hold the first mirror (202) and / or the second mirror (210) on two opposite sides (238a, 238b), each different from the first side (220) and the second side (224).

23. Beam combiner (200) according to one of claims 20 to 22, wherein the side guides (236) each have at least one groove (240).

24. Beam combiner (200) according to one of the preceding claims, wherein the holder (218) has at least one positioning unit (242) which is configured to define a preferred orientation and / or a preferred positioning of the holder (218) during installation.

25. Beam combiner (200) according to one of the preceding claims, wherein the positioning unit (242) has at least one receptacle (244) for a positioning pin (245).

26. Beam combiner (200) according to one of the preceding claims, wherein the support (218) defines a standing surface (246) on the first side (220).

27. Beam combiner (200) according to one of the preceding claims, wherein the first mirror (202) and / or the second mirror (210) is partially transparent.

28. Beam combiner (200) according to one of the preceding claims, wherein at least one of the mirrors (202, 210) comprises a coating due to which the mirror (202, 210) is reflective for light of one wavelength range and transmissive for light of at least one other wavelength range.

29. Lighting device (12), in particular endoscope lighting device, comprising at least one beam combiner (200, 200', 200") according to one of the preceding claims.

30. Lighting device (12) according to claim 29, further comprising at least two lighting elements (248), wherein the beam combiner (200, 200', 200") defines two different input sides (250a, 250b), wherein the two lighting elements (248) are each arranged on one of the input sides (250a, 250b), and wherein the beam combiner (200, 200', 200") is configured to couple light of the lighting elements (248) into a common optical path (54).

31. Lighting device (12) according to claim 29 or 30, further comprising a housing (252) with a cover (254), wherein the cover (254) has a recess (256) in which the connector (222) of the beam combiner (200) is at least partially received.

32. Lighting device (12) according to claim 31, wherein the connector (222) has play in the recess (256).

33. Lighting device (12) according to claim 32, wherein the recess (256) has a bottom (258), and wherein in an assembled state the connector (222) is arranged at a distance from the bottom (258).

34. Lighting device (12) according to claim 33, wherein a deformable spacer (260) is arranged between the connector (222) and the floor.

35. Lighting device (12) according to one of claims 29 to 34, further comprising a further beam combiner (262), wherein the Beam combiner (200) and the further beam combiner (262) define a common optical path (54).

36. Lighting device (12) according to claim 35, wherein the connector (222) of the beam combiner (200) is formed integrally with the connector (222) of the further beam combiner (262).

37. Lighting device (12) according to one of claims 31 to 36, wherein the beam combiner (200) and / or the further beam combiner (262) at least almost completely fills a cavity (264) of the housing (252).

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