Optical arrangement for efficient coupling of a sample light into an optical analyzer, the optical arrangement comprising a kÖhler illumination optics

Abstract

Optical arrangement (1) for efficient coupling of a sample light (2') into an optical analyzer (18), the optical arrangement (1) comprising: a Köhler illumination optics (6) for receiving a light (2) emitted from at least one light source (10) and comprising at least one field stop (9); a transmission sample space (3) for receiving a sample (5); and a coupling optics (12) comprising a coupling exit (14) for being coupled to the optical analyzer (18), wherein the Köhler illumination optics (6), the transmission sample space (3) and the coupling optics (12) define at least partially an optical pathway for the light (2) received by the Köhler illumination optics (6), and the Köhler illumination optics (6) being configured to illuminate with the light (2) at least partially a sample (5) when being received by the transmission sample space (3) and to generate in the sample (5) an image (11) of the at least one field stop (9), and wherein the coupling optics (12) is configured to receive the light (2) which is transmitted through the sample (5) being the sample light (2') and to project, together with the image (11) of the at least one field stop (9), an image (15) of the sample (5) at least partially onto the coupling exit (14).

Description

[0001] Optical arrangement for efficient coupling of a sample light into an optical analyzer, the optical arrangement comprising a Köhler illumination optics Field of the Invention

[0002] The invention relates to an optical arrangement for efficient coupling of a sample light into an optical analyzer comprising a Köhler illumination optics and an optical analyzer system comprising the optical arrangement together with the optical analyzer in the general field of applied optics and specifically in the field of In Vitro diagnostics (IVD), where optical arrangements are used together with optical analyzers to analyze samples, specifically medical samples. The optical arrangement is specifically applied to the field of non microscopic IVD analyzers, specifically comprising a spectrometer.

[0003] Background of the Invention

[0004] Often illumination devices provide a low optical flux for spectral analysis of samples resulting in a low signal to noise ratio of a detector, such as a photodiode array (PDA) output. Further, known optical concepts may only contain a single lens element, which makes the instrument sensitive to tolerances of components beyond the optics. Therefore, the beam propagation may be highly undefined.

[0005] In Fig. 5, a schematic example for such an illumination device 501 of the known art is shown as it is used for example in an existing oximeter module 500. The illumination device 501 comprises optics such as a single lens 506 and sends light from a white LED 504 and from a neon lamp 505 being at least partially overlapped by the use of a beam splitter 508 through a sample 509 in a cuvette 510. The light that has passed the sample 509 may be considered a sample light and is guided along an optical path 514 via an optical fiber bundle 502 into a grating spectrometer 503. In Fig. 6, a photograph of an entrance 502i of an optical fiber bundle 502 as it may be used in the example of Fig. 5 is shown. The optical fiber bundle 502 comprises several single fibers 5022 namely nine fibers, which are randomly / arbitrarily arranged at the entrance 502i of an optical fiber bundle 502.

[0006] The light from the white LED 504 is used for performing an absorption measurement in the oximeter module 500, whereas the light from the neon lamp 505 is used for a wavelength calibration.

[0007] The principle shown in Fig.5 may still be improved in terms of the optical flux for spectral analysis of samples and therefore the signal to noise ratio of the PDA output may be improved. The concept used in this illumination device 501 may be improved also in view of tolerances of components beyond the optics and the beam propagation may be improved.

[0008] As an example, EP1987762 Al describes an oximeter that has a measuring source of light that is a polychromatic light emitting diode, which emits measuring radiation for determination of thehemoglobin derivatives in a spectral region, where hemoglobin derivatives has a significant absorption.

[0009] In " Kohler illumination", Wikipedia, 06.10.2024, XP093292015, the principles of the Kohler microscopy are described.

[0010] US7576911 B1 describes a microscope illuminator system suitable for both critical source illumination and Köhler-type illumination without substantially altering the elements within the optical path.

[0011] US7636158 B1 describes an optical coupling relay system has an imaging optical system having an object plane, an exit pupil and an image plane. The system relates to a microscope for a high performance image analyzing system.

[0012] Summary of the Invention

[0013] It is therefore desirable to provide an optical arrangement and an optical analyzer system comprising the optical arrangement having a high optical flux for spectral analysis of a sample and an improved signal to noise ratio. Moreover, an optical arrangement and an optical analyzer system with a high stability against tolerances of components beyond the optics and a defined beam propagation are desired.

[0014] At least one of these improvements are achieved by the aspects of this disclosure, i.e. the subject matter defined by the independent claims. Other advantageous effects and / or improvements are achieved by the specific embodiments, i.e. the corresponding subject matter covered by the dependent claims.

[0015] According to a first aspect, an optical arrangement, i.e. an illuminator, for efficient coupling of a sample light into an optical analyzer of an IVD instrument, specifically a non-microscopic IVD analyzer, e.g. comprising a spectrometer, comprises: a Köhler illumination optics for receiving a light emitted from at least one light source and comprising at least one field stop; a transmission sample space for receiving a sample; and a coupling optics comprising a coupling exit for being coupled to the optical analyzer, wherein the Köhler illumination optics, the transmission sample space and the coupling optics define, specifically in that very order, at least partially an optical pathway for the light received by the Köhler illumination optics, and the Köhler illumination optics being configured to illuminate with the light at least partially a sample when being received by the transmission sample space and to generate in the sample an image of the at least one field stop, and wherein the coupling optics is configured to receive the light which is transmitted through the sample being the sample light and to project, together with the image of the at least one field stop, an image of the sample at least partially onto the coupling exit. The coupling optics comprises a coupling aperture stop configured to define a telecentric exit pupil at the coupling exit.The optical arrangement provides a high optical flux for spectral analysis of a sample and an improved signal to noise ratio. Moreover, the optical arrangement may provide a high stability against tolerances of components beyond the optics and a defined beam propagation.

[0016] The sample light having passed the coupling exit is not required to be de-imaged before entering the optical analyzer. In other words, the light, that leaves the coupling exit, may directly, with all information that it carries (i.e. all images that it contains), be analyzed by the optical analyzer. The Köhler illumination optics, the transmission sample space and the coupling optics may be considered the three core elements and / or spaces of the optical arrangement which may specifically in that order define at least partially, i.e. at least a part of the optical pathway for at least a portion of the light received by the Köhler illumination optics.

[0017] The Köhler illumination optics is configured for receiving a light emitted from at least one light source, wherein the at least one light source is not necessarily a part and / or element and / or component of the optical arrangement. The Köhler illumination optics may be housed in a housing and may have one or more openings for receiving light emitted from one or more light sources. Alternatively, the Köhler illumination optics is not housed in a housing and the Köhler illumination optics is aligned and / or oriented in such a way that at least some of the light emitted by the one or more light sources may enter the Köhler illumination optics and travel along the optical path of the Köhler illumination optics. In a specific embodiment, the light of one single light source is received by the Köhler illumination optics. In another embodiment, the light of two light sources is received by the Köhler illumination optics. For each light source of a plurality of light sources, an optical path is defined. For example, if the light of two light sources is received, two optical pathways which may be considered branches are dedicated respectively to the corresponding light of each light source. The two branches may be oriented towards each other in a right angle. In one pathway or in all pathways, a field stop may be positioned to be passed by the corresponding light. The light of the corresponding light source may uniformly illuminate the corresponding field stop that is positioned in the corresponding optical pathway and thereby also defines the optical pathway.

[0018] The Köhler illumination optics is configured to illuminate, specifically uniformly and / or homogeneously illuminate with the received light at least partially a sample when being received by the transmission sample space. In other words, the Köhler illumination optics is configured to illuminate, specifically uniformly and / or homogeneously illuminate with the light at least partially a sample space and as a consequence when a sample is received by the sample space, the Köhler illumination optics illuminates with the light at least partially the sample uniformly.

[0019] Further, the Köhler illumination optics is configured to generate in the sample an image of the at least one field stop. Specifically, if the light of two light sources is received and a field stop is provided in each pathway of the correspondingly received light, the Köhler illumination opticsmay be configured to project the images of each field stop into the sample space, specifically in a center plane of the sample space and more specifically in a center plane of a cuvette if received and / or positioned in the sample space.

[0020] The transmission sample space (herein also denoted “sample space”) is configured for receiving a sample, wherein the sample itself is not comprised by the optical arrangement. The transmission sample space is configured to allow transmission of the light through the sample when the sample is received. For example, the transmission sample space may comprise a holder to receive a cuvette, a slide and / or another sample support and / or container. The transmission space may also comprise a cuvette, a slide and / or another sample support and / or container. When a sample is received by the transmission sample space, specifically by the cuvette, the slide and / or another sample support and / or container positioned in the sample space and the light passes the sample, the light interacts with the sample compounds, i.e. specifically molecules, aggregates etc. For example, the light is elastically and / or inelastically scattered by the sample molecules and / or by larger aggregates if present in the sample. The light that has passed the sample therefore carries information about the sample based on such scatter effects and is hence denoted sample light herein.

[0021] The coupling optics comprises a coupling exit that may be directly or indirectly optically coupled to the optical analyzer. The coupling exit may be a position, which corresponds to a coupling focus point. The coupling optics is configured for receiving the sample light for example via a coupling entrance. The optical arrangement, specifically the coupling optics in combination with the other components is configured to project - together with the image of the at least one field stop - an image of the sample at least partially onto the coupling exit, which is the position, where an optical analyzer is optically coupled to the optical arrangement either directly or indirectly, for example via an optical fiber arrangement. It is to be noted that even though such images are projected onto the coupling exit, the optical arrangement of the present disclosure is not used per se as an imaging and / or mapping technique to project an image into a plane for the sake of topographic analysis. The optical arrangement may rather be realized in a non-microscopic and / or non-imaging IVD analyzer comprising a spectrometer.

[0022] The term “coupled” may refer specifically to an optical coupling, i.e. a clear and / or open pathway along which a light can propagate between two entities and / or elements, which are coupled to each other. Alternatively, or in addition the term “coupled” may refer to a mechanical and / or an electrical coupling and / or a coupling for a data transfer.

[0023] The phrase “a coupling optics comprising a coupling exit for being coupled to the optical analyzer” specifically refers to an optical coupling. The coupling optics may however in addition also be mechanically and / or electrically and / or digitally coupled to the optical analyzer.The “light” may specifically refer to a light comprising spectral components in the visible range, in the (near to far) infrared range and / or in the (near to far) UV range.

[0024] A “field stop” typically corresponds to an aperture and / or diaphragm that determines the extent of the field of view in an optical system. It typically effectively limits the size of the image and controls the area of the object that is visible through the system.

[0025] The field stop may in general comprise the following functions:

[0026] Defining the Field of View: A field stop limits the locations (the scene) that are transmitted by an optic. An aperture stop operates in the angular domain while a field stop operates in the spatial domain.

[0027] Reducing Stray Light: The field stop may help in excluding light from outside the desired field of view, thereby improving contrast and reducing image degradation caused by stray light.

[0028] Improving Image Quality: By limiting the image-forming light to a specific region, the field stop may help in reducing aberrations in certain parts of the optical field, potentially leading to sharper images.

[0029] In most optical systems, the field stop may be positioned at and / or in a specific plane where it can effectively limit the image field. For instance, in a microscope, the field stop may be located at a plane conjugate to the object plane and the image plane, usually at the diaphragm of the eyepiece. It is important to note that a field stop is different from an aperture stop. While the field stop controls the size of the field of view, the aperture stop controls the amount of light entering the system and affects depth of field, brightness, and diffraction.

[0030] The Köhler illumination optics may comprise a 22 Köhler aperture stop (i.e. an aperture stop of the Köhler illumination optics) that is configured to define a numerical aperture of the light received and / or transmitted by the Köhler illumination optics. The coupling optics comprises a coupling aperture stop (an aperture stop of the coupling optics) configured to define a telecentric exit pupil at the coupling exit. The 22 Köhler aperture stop may specifically be configured to define a numerical aperture NA of the light received by the Köhler illumination optics at the position of the light source.

[0031] As an effect of the above, the 22 Köhler aperture stop is configured to control the numerical aperture of the light specifically at the coupling exit, where the light may be considered and / or imagined as a plurality of cones and the numerical aperture may be considered and / or imagined as the opening angle of the cones. The coupling aperture stop of the coupling optics is configured to define the telecentric exit pupil at the coupling exit, which may be considered and / or imagined as the orientation of the axes, specifically the parallel orientation of the axes of the cones, also being known as the “telecentricity”. This telecentric configuration at the coupling exit may specificallybe adapted to the etendue of the spectrometer's fiber bundle, ensuring that no light is lost due to angular mismatch at the fiber facets.

[0032] In a preferred embodiment, the coupling aperture stop is positioned such that it coincides with the back focal plane of the coupling optics. This configuration effectively 'filters' the light such that only those light cones that can be fully accepted by the numerical aperture of the fiber bundle are projected onto the coupling exit, thereby eliminating stray light and maximizing the Signal -to-Noise ratio.

[0033] Mostly due to the inherent characteristics of the described “telecentricity”, the optical flux hitting the photodiode array (PDA) can be tremendously increased. In previous experiments using an embodiment of the invention, the optical flux hitting the photodiode array was increased by a factor of 60 as compared to a prior art setup, namely an oximeter as described above and used in a commercially available IVD instrument.

[0034] A particular advantage of the bilateral telecentricity of the coupling optics is the creation of a 'defined beam geometry' at the interface to the optical analyzer. Unlike standard imaging optics, where the chief ray angle varies with the field position, the present invention ensures that the entrance conditions for every fiber in a bundle are identical. This solves the technical problem of 'spectral tilting' or 'vignetting' in high-sensitivity IVD measurements, allowing for a signal-to-noise ratio improvement of at least one order of magnitude compared to non-telecentric relay systems. In other words, the bilateral telecentricity of the coupling optics creates a 'defined beam geometry' that decouples the spectral performance of the analyzer from the mechanical tolerances of the coupling exit. Because the exit pupil is located at infinity (telecentric), the chief rays of all light cones at the coupling exit are parallel to the optical axis. This ensures that the etendue of the sample light is optimally matched to the acceptance etendue of the optical analyzer across the entire field If the 22 Köhler aperture stop and the coupling aperture stop are provided, the 22 Köhler aperture stop may be optically conjugated with the coupling aperture stop (original image - image relation). As a consequence the illumination at the coupling exit is spatially homogeneous and telecentric. To resume the advantageous embodiment above, an optical arrangement for efficient coupling of a sample light into an optical analyzer, the optical arrangement comprising: a Köhler illumination optics for receiving a light emitted from at least one light source and comprising at least one field stop; a transmission sample space for receiving a sample; and a coupling optics comprising a coupling exit for being coupled to the optical analyzer, wherein the Köhler illumination optics, the transmission sample space and the coupling optics define at least partially an optical pathway for the light received by the Köhler illumination optics, and the Köhler illumination optics being configured to illuminate with the light at least partially a sample when being received by the transmission sample space and to generate in the sample an image of the at least one field stop, and wherein the coupling optics is configured to receive the light which is transmitted through thesample being the sample light and to project, together with the image of the at least one field stop, an image of the sample at least partially onto the coupling exit, wherein the Köhler illumination optics may comprise a 22 Köhler aperture stop that is configured to define a numerical aperture of the light transmitted an / or received by the Köhler illumination optics and / or wherein the coupling optics may comprise a coupling aperture stop configured to define a telecentric exit pupil at the coupling exit.

[0035] The optical arrangement may have conjugated field planes: The at least one field stop, the center plane in the sample and / or in the sample cuvette to which the image of the at least one field stop is projected and the coupling exit to which the image of the at least one field stop and the sample is projected, are optically conjugated to each other.

[0036] The optical arrangement may have conjugated pupil planes: The lights source(s) is / are conjugated to the pupil. In other words, the light source(s) is / are imaged onto the pupil plane.

[0037] In the field of optics, the „numerical aperture” (NA) is a dimensionless value that indicates the range of angles over which light can be accepted or emitted by an optical system. The inclusion of the refractive index in its definition ensures that the NA remains constant for a beam transitioning between materials, as long as there is no refractive power at the interface. While its precise definition may vary across different branches of optics, NA is frequently used to describe the acceptance cone of a microscope objective, reflecting its capacity to gather light and resolve detail. It is also used in fiber optics to denote the range of angles within which light, when entering the fiber, will propagate through it effectively. For example in microscopy, the NA is defined by NA = n sin θ

[0038] where n is typically the index of refraction of the medium the sample / specimen is embedded in. The situation may specifically refer to a case in microscopy called "homogeneous immersion": The specimen is embedded in a medium (immersion oil) that has the same refractive index as the subsequent optics. This may involve the cover glass or the front lens of the microscope objective. This situation has two advantages: 1. an increase in NA due to n>l and 2. no refraction in air between the sample and the front lens. This provides a better control over the aberrations in the optical path.

[0039] “Telecentricity” refers to a property of optical systems, primarily lenses, where the chief rays (the central rays that pass through the center of the aperture stop) are parallel to the optical axis in either the object space, the image space, or both. This unique attribute is particularly valuable in precision imaging and metrology applications because it ensures that the magnification of the lens does not change with the object's distance from the lens, thereby minimizing distortion.

[0040] “Kohler illumination” may in general be understood as a technique that is often used in optical microscopy to provide uniform illumination of the sample. The Köhler illumination opticsaccording to the above aspect or embodiment may therefore specifically be suited to achieve a uniform and / or homogeneous illumination of the sample. Kohler illumination allows for the minimization of artefacts such as shadows and glare, ensuring that the light evenly illuminates the specimen without emphasizing the light source's structure.

[0041] An “aperture stop” is typically an essential component in an optical system that limits the amount of light entering the system if the aperture stop is also the first optical element of the system. If the aperture stop is inside it, then more light enters the system than is transmitted at the end. In that case the aperture stop limits the amount of light transmitted by and / or through the system. It is usually a circular diaphragm placed at a specific location within the system to control the brightness and impact other optical properties. The aperture stop may in general comprise the following functions:

[0042] Controlling Light Intensity: By adjusting the size of the aperture stop, the amount of light that passes through the optical system may be increased or decreased, affecting the brightness of the image.

[0043] Affecting Depth of Field: The size of the aperture may influence the depth of field, which is the range of distances within which objects appear acceptably sharp. A smaller aperture may increase the depth of field, whereas a larger aperture may decrease it.

[0044] Reducing Aberrations: Certain optical aberrations, like spherical aberrations, may be reduced by adjusting the aperture stop. This can improve overall image quality.

[0045] Influencing Diffraction Effects: The diameter of the aperture stop may also affect diffraction, which can impact image resolution. A very small aperture may increases diffraction, leading to a loss of sharpness and / or optical resolution.

[0046] Defining the Numerical Aperture: In systems like microscopes, an aperture stop may help to define the numerical aperture, which is a critical parameter determining the resolving power and brightness of the system.

[0047] While the aperture stop typically controls the amount of light corresponding to and / or comprising the optical flux entering the optical system and influences depth of field, the field stop may limit the extent of the field of view. Together, both types of stops may play crucial roles in defining the overall performance of the optical system. In more detail, both types of stops influence the amount of light measured in watts corresponding to the optical flow (flux). However, if considering a fixed field provided by the field stop, then the aperture stop controls the brightness, i.e. the flux per area (irradiance). This case may refer to or resemble a case in photography or microscopy, for example. With respect to the position of the aperture stop, an important special case may be the telecentric pupil position. In this case, the aperture stop is located in the respective rear focal plane of theoptical subsystem. If tel ecentri city is not required, then the coma-free pupil position is often selected in order to eliminate the corresponding image error.

[0048] An “exit pupil” my typically refer to the image of an aperture stop as seen from the image plane (or sensor) through the back of the lens system. This may correspond to the point where all the light rays from the object converge after passing through the optical system specifically for rays that start at the original aperture stop. The physical aperture stop, entrance pupil and exit pupil are optically conjugated to each other. In other words, they have an object (= original)-image relationship to each other. For determining the exit pupil in a lens section, the position is considered, where the principal rays intersect with the optical axis. The principal rays typically start on the axis at the location of the physical aperture stop. For an observer and / or a detector positioned at the exit pupil, the entire field of view is clearly visible without vignetting. In practical applications, such as in cameras and telescopes, the exit pupil position and size are typically crucial for efficient light collection and optimal image quality.

[0049] The coupling optics may correspond to a de-magnifier, specifically being configured to project the image of the sample at least partially onto the coupling exit as an image of a reduced size. Unlike the microscopic application of a Kohler illumination principle in the prior art, the present optical arrangement achieves a projection of a de-magnified image of the sample onto the coupling exit using the Kohler illumination principle.

[0050] The Köhler illumination optics may be configured for receiving the light comprising a first light emitted by a first light source and a second light emitted by a second light source, specifically, wherein the optical arrangement may comprise the first light source, specifically a white light source, such as a white light LED; and / or wherein the optical arrangement may comprise the second light source, specifically a neon source, such as a neon bulb.

[0051] The white light LED may be used for the optical analysis of the sample, for example for extinction and / or spectroscopic measurements such as absorption spectroscopy (e.g. Infrared spectroscopy, Raman spectroscopy, UV / vis spectroscopy etc.). The neon light may be used for wavelength calibration. Neon light may be characterized by an emission light emitted by a neon bulb that comprises multiple spectral lines at different wavelengths.

[0052] The at least one field stop may comprise: a first field stop positioned in the optical pathway of the first light; and / or a second field stop positioned in the optical pathway of the second light, specifically, wherein the Köhler illumination optics may comprise a beam splitter positioned in the optical pathway behind the first field stop and the second field stop for superimposing and / or overlapping the first light with the second light, or vice versa.

[0053] In other words, the Köhler illumination optics may receive the first light, i.e. the light of the first light source along a first optical pathway (also denoted first branch) and the second light, i.e. thelight of the second light source along a second pathway (also denoted second branch). The first and the second pathways may be aligned at an angle, specifically a right angle with respect to each other. The beam splitter may be positioned where the two pathways cross each other to overlap the two light rays and / or beams with each other.

[0054] The Köhler illumination optics may be configured to evenly shed at least a portion of the first light and the second light on at least a portion of the sample when being received by the transmission sample space with. In other words, the Köhler illumination optics may be configured to illuminate the sample uniformly and / or homogeneously, specifically with the first light and / or the second light; and / or wherein the coupling optics may be configured to project, together with the image of the at least one field stop, an image of the sample uniformly and / or homogeneously onto the coupling exit, specifically with the first light and / or the second light.

[0055] The terms “behind” and / or “after” a component in the context of the position in a pathway may be considered as a position being more downstream with regards to the component. The terms “in front” and / or “before” a component in the context of the position in a pathway may be considered as a position being more upstream with regards to the component.

[0056] The Köhler illumination optics may comprise a first Kohler collector, positioned in the optical pathway of the first light, specifically positioned behind (downstream of and / or after) the first field light source and in front of (upstream of and / or before) the beam splitter, i.e. between the first field light source and the beam splitter; and / or a second Kohler collector, positioned in the optical pathway of the second light, specifically behind (downstream of and / or after) the second light source and in front of (upstream of and / or before) the beam splitter; and / or a relay comprising a relay collimator (collimator of the relay) and a relay condenser (condenser of the relay) positioned in the optical pathway of the first light and / or the second light, specifically behind the beam splitter; and specifically the Köhler illumination optics may comprise the 22 Köhler aperture stop positioned in the optical pathway of the first light and / or the second light between the relay collimator and the relay condenser, specifically in a focus point of the relay collimator.

[0057] The collimator may specifically be positioned upstream of the condenser.

[0058] A “collimator” is typically an optical device / element that narrows a light beam of particles or waves to make them parallel. Narrowing is realized in the angular space of the beam. In the spatial domain (cross section), however, an enlargement is realized.

[0059] A „condenser” is typically an optical component / element which may be used in microscopes and other optical instruments to focus and direct light onto a specimen or object. Its primary function may be to gather light from a broad source and concentrate it into a cone of light that illuminates the specimen uniformly and efficiently. Condensers may be vital for achieving optimal illumination and enhancing the resolution and contrast of the observed image. The condensertypically has the opposite function of a collimator: the cross-section in the spatial domain is reduced, but the divergence (NA) increases. Spatial and angular domain behave reciprocally to each other; collimator and condenser also behave reciprocally to each other.

[0060] Condensers may consist of one or more lenses arranged to focus and direct light. Many condensers may incorporate an adjustable diaphragm (aperture stop) that allows users to control the amount of light and adjust the numerical aperture. High-quality microscopes often provide mechanisms to precisely align the condenser with the optical axis of the microscope.

[0061] There are several types of condensers:

[0062] Abbe Condenser: One of the simplest types, it usually consists of two optical lenses and provides basic illumination and may be suitable for low to medium magnification.

[0063] Achromatic Condenser: Corrects for chromatic aberrations, providing sharper and clearer images and may be used for high-precision applications.

[0064] Aplanatic Condenser: Minimizes spherical aberrations for an even higher level of image quality. Darkfield Condenser: Designed to provide darkfield illumination by blocking the central light and allowing only oblique rays to illuminate the specimen and may be useful for observing transparent or unstained specimens.

[0065] Phase Contrast Condenser: Specifically designed for phase contrast microscopy, it enhances contrast by converting phase shifts in light passing through a transparent specimen into brightness changes.

[0066] The use of a condenser may have several advantages: Proper use of a condenser may ensure even illumination, which is critical for achieving high-resolution and high-contrast images. Various types of condensers (e.g., darkfield, phase contrast) may allow for different types of illumination techniques tailored to specific needs. Adjustable diaphragms and alignment mechanisms may provide precise control over illumination, accommodating different specimen types and observation techniques.

[0067] The optical arrangement may further comprise an optical fiber arrangement for indirectly coupling the coupling optics to the optical analyzer, the optical fiber arrangement may comprise an optical fiber entrance configured for being coupled to the coupling exit of the coupling optics, an optical fiber exit configured for being coupled to the optical analyzer and a plurality of optical fibers being arranged in a circle packing at the optical fiber entrance and extending from the optical fiber entrance to the optical fiber exit.

[0068] The use of an optical fiber or an optical fiber arrangement for coupling the sample light indirectly into the optical analyzer allows guiding the light in flexible manner that does not require a lot of adjustment around turns and bends. Along the length of the optical fiber or the optical fiberarrangement, the light does typically not escape when the optical fiber or the optical fiber arrangement is at least partially enclosed by a shielding element.

[0069] The term “circle packing” refers to the arrangement of circles (i.e. round (entrance) planes with circular circumference) within a given boundary or container in such a way that the circles do not overlap and are placed as densely as possible. The objective is typically to maximize the number of circles or the packing density, which is the proportion of the area of the region that is covered by the circles. The ratio of the total area of the circles to the area of the container is defined: For an infinite plane using equal-sized circles, the highest achievable density is about 0.9069, known as the hexagonal or honeycomb packing.

[0070] In general, there are different types of circle packing:

[0071] Hexagonal Packing: The most efficient, i.e. optimal way of packing equal-sized circles in an infinite plane, where each circle is surrounded by six others in a hexagonal arrangement.

[0072] Square Packing: Less efficient than hexagonal packing, where each circle is placed in a square grid pattern.

[0073] Random Packing: Circles are placed randomly within the boundary, typically resulting in a lower packing density.

[0074] Circle packing can occur in various container shapes, such as squares, rectangles, circles, and other polygons. The geometry of the container (i.e. 2D container plane) influences the packing strategy and density. In the present disclosure, the container shape may typically be considered a round shape.

[0075] The plurality of optical fibers may comprise and / or correspond to an odd number, specifically to one, three or seven fibers. An odd number of fibers is specifically efficient in achieving a tightest packing arrangement. In that respect, the plurality of optical fibers may be polygonally arranged at (least at the very position of) the optical entrance by a tightest packing arrangement, specifically forming a hexagonal arrangement geometry.

[0076] The plurality of optical fibers may be linearly arranged at the optical exit, which increases the efficiency and / or practicability of the coupling of light into a spectrometer.

[0077] The fiber arrangement may comprise a supporting structure configured to support the geometric arrangement of the plurality of optical fibers. The supporting structure may comprise a filling material in which the individual fibers are embedded and therefore stabilized in their orientation towards each other. For example, the hexagonal arrangement geometry at the optical entrance of the optical arrangement and / or the linear arrangement geometry at the optical exit of the optical arrangement may be stabilized by the supporting structure.The sample space may be positioned directly between the Köhler illumination optics and the coupling optics. A direct coupling of the sample light into the coupling optics avoids losses and is therefore efficient. In other words, the Köhler illumination optics and the coupling optics may be spaced apart from each other such that a space is left between them to receive and / or position therein a sample, a sample together with a cuvette and / or a sample together with a cuvette and a cuvette holder.

[0078] The coupling optics may comprise a coupling collimator and a coupling condenser and specifically wherein the coupling aperture stop may be positioned between the coupling collimator and the coupling condenser, specifically in a focus point of the coupling collimator.

[0079] A “collector”, i.e. an optical collector is typically a device or component used to gather, concentrate, and, in some cases, redirect light from a source. These systems are crucial in applications where maximizing light collection and efficiency is important, such as solar energy systems, lighting, and various optical instruments. A collector, as used herein, may specifically comprise lenses and / or reflectors, for example concavely shaped reflectors. Lenses (convex, Fresnel) collect and focus light. Reflectors (parabolic, elliptical) direct and concentrate light into specific regions. In general, a collector may also comprise concentrators, light pipes, optical fibers and / or light guides.

[0080] The sample space may comprise a cuvette for receiving the sample and / or the sample space may be configured to receive a cuvette for receiving the sample. The sample space may comprise a support, such as a slide for receiving the sample and / or the sample space may be configured to receive a support for receiving the sample. The sample space is to be understood in a broad sense as it may provide the space and specifically means such as a holder mechanism for receiving a sample support and / or a sample container. A sample container such as a cuvette is useful to receive a sample that is at least partially in a liquid state. A solid sample or solid remains of a liquid sample may be supported by a sample support, such as a glass slide.

[0081] The optical arrangement may provide multiple lens elements realized as transmissive and / or reflective elements, specifically the optical arrangement may provide 12 lens elements in overall sum. For example, in one embodiment each collector, condenser, collimator and collector may comprise a double lens system. Comprising two collectors, one collimator, one condenser and two collectors, the optical arrangement then provides 12 lens elements in total.

[0082] The advantage of providing a multitude of lens elements instead of one single lens / lens element is given in that the instrument becomes more stable in view of tolerances of components beyond the optics and as a result, the beam propagation becomes better defined.In a specific embodiment with two light sources providing light, respectively, the optical arrangement for efficient coupling of a sample light into an optical analyzer may comprise, specifically arranged in that order:

[0083] a Köhler illumination optics for receiving a first light emitted by a first light source, such as a white light LED, and a second light emitted by a second light source, such as a neon source and the Köhler illumination optics comprising a first field stop positioned in the optical pathway of the first light; and a second field stop positioned in the optical pathway of the second light;

[0084] a transmission sample space for receiving a sample; and

[0085] a coupling optics comprising a coupling exit for being coupled to the optical analyzer, wherein the Köhler illumination optics, the transmission sample space and the coupling optics define at least partially an optical pathway for the first light and the second light received by the Köhler illumination optics, and the Köhler illumination optics being configured to illuminate with the first and the second light at least partially a sample when being received by the transmission sample space and to generate in the sample an image of the first field stop and the second field stop, and wherein the coupling optics is configured to receive the light (comprising at least portions and / or components of the first light and the second light) which is transmitted through the sample being the sample light and to project, together with the image of the first field stop and the second field stop, an image of the sample at least partially onto the coupling exit,

[0086] wherein the coupling optics may comprise:

[0087] a coupling aperture stop configured to define a telecentric exit pupil at the coupling exit; and

[0088] a coupling collimator and a coupling condenser, wherein the coupling aperture stop is positioned between the coupling collimator and the coupling condenser,

[0089] wherein the Köhler illumination optics may comprise:

[0090] a beam splitter positioned in the optical pathway behind the first field stop and the second field stop for overlapping the first light with the second light or vice versa;

[0091] a 22 Köhler aperture stop that is configured to define a numerical aperture of the first light and the second light received by the Köhler illumination optics;

[0092] a first Kohler collector, positioned in the optical pathway of the first light, specifically positioned upstream (in front of) the first field stop and in front of the beam splitter; a second Kohler collector, positioned in the optical pathway of the second light, specifically behind the first field stop and in front of the beam splitter;a relay comprising a relay collimator and a relay condenser positioned in the optical pathway of the first light and / or the second light, specifically behind (i.e. downstream of) the beam splitter; and wherein the 22 Köhler aperture stop is positioned in the optical pathway of the first light and the second light between the relay collimator and the relay condenser, specifically in a focus point of the relay collimator.

[0093] In another specific embodiment with only one light source providing light, the optical arrangement for efficient coupling of a sample light into an optical analyzer may comprise:

[0094] a Köhler illumination optics for receiving a light emitted by a single light source, such as a white light LED, and the Köhler illumination optics comprising a single field stop positioned in the optical pathway of the light;

[0095] a transmission sample space for receiving a sample; and

[0096] a coupling optics comprising a coupling exit for being coupled to the optical analyzer, wherein the Köhler illumination optics, the transmission sample space and the coupling optics define at least partially an optical pathway for the light (the single ray or bundle of light) received by the Köhler illumination optics, and the Köhler illumination optics being configured to illuminate with the light at least partially a sample when being received by the transmission sample space and to generate in the sample an image of the field stop, and wherein the coupling optics is configured to receive the light which is transmitted through the sample being the sample light and to project, together with the image of the field stop, an image of the sample at least partially onto the coupling exit,

[0097] wherein the coupling optics may comprise:

[0098] a coupling aperture stop configured to define a telecentric exit pupil at the coupling exit; and

[0099] a coupling collimator and a coupling condenser, wherein the coupling aperture stop is positioned between the coupling collimator and the coupling condenser,

[0100] wherein the Köhler illumination optics may comprise:

[0101] a 22 Köhler aperture stop that is configured to define a numerical aperture of the light received by the Köhler illumination optics;

[0102] a Kohler collector, positioned in the optical pathway of the light, specifically positioned upstream (in front of) the field stop and in front of the beam splitter;

[0103] a relay comprising a relay collimator and a relay condenser positioned in the optical pathway of the light; and wherein the 22 Köhler aperture stop is positioned in the opticalpathway of the light between the relay collimator and the relay condenser, specifically in a focus point of the relay collimator.

[0104] According to a second aspect, an optical analyzer system comprises the optical arrangement of any one of the herein described embodiments and the optical analyzer. The optical analyzer system has all the advantages and technical effects of the according embodiments of the optical arrangement described herein.

[0105] The optical analyzer may comprise at least one of: a photometer, a spectrometer, specifically a Raman spectrometer, an IR spectrometer, a UV-vis spectrometer, a fluorescence spectrometer. The listed optical analyzers may be useful to gain information of a sample, specifically a medical sample.

[0106]

[0107] In the following, some example embodiments will be described in detail, wherein the invention should not be understood to be limited to the examples and embodiments described. The following examples, embodiments and figures are provided to aid the understanding of the present invention, the true scope of which is set forth in the appended claims. Single features being described in a particular embodiment may be arbitrarily combined, given that they are not excluding each other. In addition, different features, which are provided together in the example embodiments are not to be considered restrictive to the invention.

[0108] Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements whereas other elements may have been left out or represented in a reduced number in order to enhance clarity and improve understanding of the aspects of the present disclosure.

[0109] The same reference numerals are used among different embodiments and examples for the same or similar elements or elements that have similar or the same effects.

[0110]

[0111] of the Fi

[0112] Fig. 1 is a schematic drawing of an optical analyzer system comprising an optical arrangement in the pupil setting to display conjugate aperture planes according to an embodiment;

[0113] Fig. 2 is a schematic drawing of the optical analyzer system comprising the optical arrangement of Fig. 1 in the field setting to display conjugate field planes according to an embodiment;

[0114] Fig. 3 is a schematic drawing of an optical fiber entrance of an optical fiber arrangement according to an embodiment;Fig. 4a is a photograph of the optical fiber entrance of the optical fiber arrangement according to Fig. 3;

[0115] Fig. 4b is another schematic drawing the optical fiber entrance of the optical fiber arrangement according to Fig. 3;

[0116] Fig. 4b is a photograph of the optical fiber exit of an optical fiber arrangement according to an embodiment;

[0117] Fig. 5 is a schematic drawing of a prior art oximeter module comprising an illumination device as often used;

[0118] Fig. 6 is a photograph of an optical fiber entrance of a prior art optical fiber arrangement as often used;

[0119] Fig. 7 is a simplified scheme of an optical arrangement displaying the conjugate field planes according to an embodiment and displaying the conjugate aperture planes according to an embodiment;

[0120] Fig. 8 shows in a scheme the technical implementation of the collector as a simple cemented doublet lens element;

[0121] Fig. 9 shows in a graph the focal length for three different wavelengths as a function of the numerical aperture;

[0122] Fig. 10 shows in a perspective scheme the rays from a Lambertian light source and the doublelens collector with a circular aperture in its rear focal plane;

[0123] Fig. 11 shows in a graph the distribution of the irradiation intensity within the illumination field diaphragm in detail;

[0124] Fig. 12 is a scheme of a prior art optical analyzer system (extracted from Wikipedia, 06.10.2024, XP093292015) comprising an optical arrangement in the pupil setting to display conjugate aperture planes according to an embodiment with marked positions for explanation of the difference to the Kohler approach; and

[0125] Fig. 13 is a scheme to illustrate the optical analyzer system according to the embodiment with respect to the Köhler illumination approach shown in Fig. 12.

[0126] Fig. 1 is a schematic drawing of an optical analyzer system 100 comprising an optical arrangement 1 in the pupil setting to display conjugate aperture planes according to an embodiment and Fig. 2 is a schematic drawing of the optical analyzer system 100 comprising the optical arrangement 1 of Fig. 1 in the field setting to display the according conjugate field planes.The optical arrangement 1, which may be understood as an “illuminator” (therefore the “optical arrangement” is interchangeably denoted herein as “illuminator”) may specifically be used in an IVD analyzer such as an oximeter, for example. The illuminator 1 according to the shown embodiment comprises 12 lens elements instead of a single lens as it is the case in the prior art oximeter module 500 shown in Fig. 5. In addition, two field stops 9, a 22 Köhler aperture stop 22 and a coupling aperture stop 23 have been integrated in the design. Therefore, the optical fiber arrangement 17 comprising one or more optical fibers and which couples the sample light 2’ from the illuminator 1 into the optical analyzer 18, such as a spectrometer, is illuminated well defined in the spatial and angular dimensions at the optical fiber entrance 17i. The optical flux hitting the photodiode array (PDA) can be increased by a factor of 60 (demonstrated in the lab) as compared to the prior art setup shown in Fig. 5 and Fig. 6, namely an oximeter as described above and used in a commercially available IVD instrument.

[0127] The optical arrangement 1 as schematically shown in Fig. 1 and Fig.2 is suited for a more efficient coupling of a sample light 2’ into an optical analyzer 18. Therefore, the optical arrangement 1 comprises three main elements: a Köhler illumination optics 6 for receiving a light 2 emitted from at least one light source 10 and comprising at least one field stop 9, a transmission sample space 3 for receiving a sample 5 and a coupling optics 12 comprising a coupling exit 14 for being coupled to the optical analyzer 18. In more detail, the Köhler illumination optics 6 is configured for receiving a first light 2i emitted by a first light source 10i and a second light emitted by a second light source IO2. The optical arrangement 1 is indicated by a dashed box, which may indicate a housing. It may also just indicate the elements that are comprised by the optical arrangement 1. However, the dashed box is not to be seen as a limiting element, it may also just assist the reader in viewing the drawing. The same applies to the dashed box indicating the Köhler illumination optics 6 and the coupling optics 12. The first and the second light sources 10i, IO2 are not drawn inside the dashed box but may be comprised by the Köhler illumination optics 6. Therefore, the dashed box is not to be considered as absolutely limiting to the elements shown therein.

[0128] The Köhler illumination optics 6, the transmission sample space 3 and the coupling optics 12 define in that order at least partially an optical pathway for the first light 2i and the second light 22 being received by the Köhler illumination optics 6.

[0129] The Köhler illumination optics 6 is configured to illuminate, with the first and / or the second light 2i, 22, at least partially and uniformly a center plane in the sample space 3 and / or a sample 5 that is received by the transmission sample space 3, specifically in a cuvette 4 that is positioned in the sample space 3. The sample space 3 comprises in this embodiment the cuvette 4 for receiving the sample 5 or the sample space 3 may be seen as only receiving a cuvette 4 for receiving the sample 5, specifically in the center plane 3’ of the sample space 3.Further, the Köhler illumination optics 6 comprises a first field stop 9i and a second field stop 92, therefore, the above mentioned at least one field stop 9 corresponds to the first field stop 9i and the second field stop 92 in this specific embodiment. The first field stop 9i is positioned in the optical pathway of the first light 2i and the second field stop 92 is positioned in the optical pathway of the second light 22. The Köhler illumination optics 6 comprises a beam splitter 20 positioned in the optical pathway behind (instead of “behind” it may be used “after” if considering the travel time of the first light 2i) the first field stop 9i and behind the second field stop 92 (instead of “behind” it may be used “after” if considering the travel time of the second light 22) for overlapping the first light 2i with the second light 22.

[0130] The optical arrangement 1 may be considered as comprising the first light source 10i, specifically a white light source, such as a white light LED and / or the optical arrangement 1 may be considered as comprising the second light source IO2, specifically a neon source, such as a neon bulb. The first light 2i emitted by the white light LED 101 may be used for the spectroscopy and the second light 22 emitted by the neon source IO2 may be used for calibration of the wavelength(s).

[0131] The Köhler illumination optics 6 further comprises a first Kohler collector 19i, positioned in the optical pathway of the first light 2i, specifically positioned behind the first light source 10i and in front of the beam splitter 20 and a second Kohler collector 192, positioned in the optical pathway of the first light 2i, specifically positioned behind the first light source 101 and in front of the beam splitter 20.

[0132] The Köhler illumination optics 6 further comprises a relay 21 that comprises a relay collimator 211 and a relay condenser 2h positioned in the optical pathway of the first light 2i and the second light 22, specifically behind the beam splitter 20. The first light 2i and the second light 22, which enter the relay 21 are spatially overlaid and have passed the respective Kohler collector 19i, 192 and the field stop 9i, 92. Therefore, the light behind the beam splitter may be considered a combined and shaped light 2”. Further, every optical element may filter and / or cut out a portion of the light 2 and as such when saying “the light”, the remaining (spectral and / or spatial) portion of the light 2 that was originally emitted is meant.

[0133] The Köhler illumination optics 6 further comprises a 22 Köhler aperture stop 22 positioned in the optical pathway of the combined and shaped light 2”, i.e. the remaining (spectral and / or spatial) portion of the originally emitted first light 2i and the second light 22 between the relay collimator 21i and the relay condenser 212, specifically in a focus point FP2L of the relay collimator 211. The 22 Köhler aperture stop 22 is configured to define a numerical aperture NA of the light 2 received by the Köhler illumination optics 6.

[0134] The Köhler illumination optics 6 is configured to generate, in the center plane 3’ of the sample space 3 and / or the sample 5 when received by the sample plane 3, an image 11 of the first fieldstop 9i and the second field stop 92. The sample space 3 is positioned in this embodiment directly between the Köhler illumination optics 6 and the coupling optics 12.

[0135] The coupling optics 12 comprises a coupling aperture stop 23 configured to define a telecentric exit pupil at the coupling exit 14. The coupling optics 12 comprises a coupling collimator 12i and a coupling condenser 122 and the coupling aperture stop 23 is positioned between the coupling collimator 12i and the coupling condenser 122, specifically in a focus point FP12i of the coupling collimator 12i. The coupling optics 12 corresponds to a de-magnifier specifically being configured to project the image 15 of the sample 5 at least partially onto the coupling exit 14 as an image of a reduced size.

[0136] The coupling optics 12 is configured to receive the sample light 2’ via a coupling entrance 13 and to project, together with the image 11 of the first field stop 9i and the second field stop 92, an image 15 of the sample 5 at least partially onto the coupling exit 14, specifically uniformly and / or homogeneously.

[0137] The optical arrangement 1 either comprises or is coupled to an optical fiber arrangement 17 for indirectly coupling the coupling optics 12 to the optical analyzer 18, the optical fiber arrangement 17 comprises an optical fiber entrance 17i configured for being coupled to the coupling exit 14 of the coupling optics 12, an optical fiber exit 172 configured for being coupled to the optical analyzer 18 and a plurality of optical fibers 17s being arranged in a circle packing at the optical fiber entrance 17i and extending from the optical fiber entrance 17i to the optical fiber exit 172.

[0138] In a preferred embodiment, the coupling aperture stop (23) may be positioned such that it coincides with the back focal plane of the coupling optics. This configuration effectively 'filters' the light such that only those light cones that can be fully accepted by the numerical aperture of the fiber bundle (16) are projected onto the coupling exit (14), thereby eliminating stray light and maximizing the Signal-to-Noise ratio.

[0139] The plurality of optical fibers 17s comprises and / or corresponds to an odd number, specifically to one, three or seven fibers as shown in Fig. 3, Fig. 4a, 4b and 4c. In the embodiments of the Fig.

[0140] 3, Fig.4a and 4b, the plurality of optical fibers 17s are polygonally arranged at the optical entrance 17i by a tightest packing arrangement, namely forming a hexagonal arrangement Further, as shown in Fig. 4c, the plurality of optical fibers 17s are linearly arranged at the optical exit 172. The fiber arrangement 17 comprises a supporting structure 25 as shown in Fig. 3 in more detail and being configured to support the geometric arrangement of the plurality of optical fibers 17s. Each optical fiber 17s comprises a core 26 surrounded by a cladding 27 and an insulating 28 as an outer surrounding. As an example that is not meant to limit the scope of the invention or the embodiments, the diameter of one core 26 may be approx. 100μm (+ / - 2μm), together with the cladding 27 approx. 140μm (+ / - 3μm) and together with the cladding 27 and the insulating 28 approx. 165μm (+ / - 5μm). The fiber arrangement 17 may be provided with a surrounding sleeve29. The diameter of the fiber arrangement 17 may for example, without limitation, be approx. 0,51 mm. The fiber arrangement 17 may comprise SFS 100 / 140 / 165T as a material.

[0141] In Fig. 4b the optical entrance 17i of the fiber arrangement 17 is shown. The grey disk may represent the area that is to be illuminated comprising at least the supporting structure 25. The seven white disks represent the single optical fibers 173, into which the light can be coupled if the coupling condition comprising a range of incident angles is met. The cones on the white disks indicate the incident sample light 2’ having a suited numerical aperture, as for example approximately 0,25 (without limitation) and being telecentric.

[0142] Compared with the prior art optical fiber bundle 502 of Fig. 6, the fiber arrangement 17 has a substantially increased coupling efficiency.

[0143] The Köhler illumination optics 6 further comprises in this embodiment a reference detector 24 for performing reference measurements of a portion of the first light 2i being transmitted through the beam splitter 20 and / or a portion of the second light being reflected off the beam splitter 20. An optical analyzer system 100 as shown in Fig. 1 and 2 may comprise the optical arrangement 1 together with the optical analyzer 18. The optical analyzer 18 may comprise at least one of: a photometer, a spectrometer, specifically a Raman spectrometer, an IR spectrometer, a UV-vis spectrometer, a fluorescence spectrometer.

[0144] In one embodiment, the elements may have the following approximate diameters and approximate focal lengths to provide a feasible example, without limitation, i.e. to which the invention and the embodiments should not be limited:

[0145] Element Diameter / mm (approx.) Focal length if applicable / mm (approx.)

[0146] First field stop 9i 2,5

[0147] Second field stop 92 2,5

[0148] First Köhler collector 19i f5= 7

[0149] Second Köhler collector 192 f6= 7,65

[0150] Relay collimator 211 fi= 16,35

[0151] Relay condenser 212f2=16,35

[0152] Köhler aperture stop 22 2,0

[0153] Cuvette 4 2,5

[0154] Coupling aperture stop 23 5

[0155] coupling collimator 12i f3= 36,37

[0156] coupling condenser 122 f4= 8,76

[0157] Optical fiber entrance 17i 0,6The diameter of the original image (Köhler aperture stop 22 to light source 10) is about 0,86mm and Köhler aperture stop 22 and light source 10 are optically conjugated.

[0158] In the following the physical concept of the optical arrangement according to a specific embodiment as for example shown in Fig. 1 and 2 is described in greater detail:

[0159] Conditions according to an embodiment

[0160] The optical arrangement 1 for efficient coupling of a sample light 2’ transmits the light that has passed through the sample 5 in the cuvette 4 to the entrance 17i of the fiber bundle / optical fiber arrangement 17. At the entrance 17i of the fiber bundle / optical fiber arrangement 17, individual / single optical fibers 17s are packed as tightly as possible in a hexagonal arrangement. As an example, without limitation, the diameter of the circumference, which includes all seven fiber cores 26, is approximately 0,43mm. In order to leave room for tolerances of all kinds, including alignment tolerances, a circle / disc with a diameter of approximately 0,6mm (example, without limitation) is illuminated with locally homogeneous irradiance at the position of the optical fiber entrance 17i.

[0161] The numerical aperture of the single optical fibers 17s is approximately 0,22 (example, without limitation). To ensure that the optical fiber arrangement 17 represents the element that determines the light transmission value of the entire optical arrangement, the optical fiber arrangement 17 should be illuminated with a moderately larger numerical aperture NAF such as for example approximately 0,25 in the angular space.

[0162] As previously mentioned, the coupling optics 12 should be telecentric, i.e. generate telecentric light that may be coupled into the optical fiber arrangement 17. This corresponds to the entrance pupil of the optical fiber arrangement 17.

[0163] At the sample space 3, the field should be preferably of circular shape with a diameter of approximately 2,5 mm, as an example, without limitation. This corresponds to the expansion of the beam at the location of the sample 5, which is generated by the upstream Köhler illumination optics.

[0164] Implementation according to an embodiment

[0165] The requirements formulated above define the exit hatch (= field on both sides; in German: “Luke”) and the exit pupil (= pupil on the image side; in German: “Pupille”) of the coupling optics, as well as its entrance hatch (= object-side field). The entrance pupil (= object-side pupil) of the coupling optics is therefore still open. A preferable position of the entrance pupil is the telecentric position, just as on the image side. This means that the coupling optics 12 can be designed as a classic telescope with infinite focal length.The absolute value of the magnification m2 of the telescope results from the ratio of the sizes of the exit hatch and entrance hatch:

[0166] |m₂|0.6= |mm / 2.5mm = 0,24

[0167] The following applies to the ratio of the partial focal lengths

[0168] |m₂|= f₄ / f₃ = 0,24 (partial focal length of the coupling condenser 12₂ / partial focal length of the coupling collimator 12₁)

[0169] From a paraxial point of view, f₄ or f₃ can be freely selected as long as their ratio is |m₂|. If both partial focal lengths are chosen very large, small aberrations result at the expense of a large transmission length. Conversely, short partial focal lengths result in a short transmission length at the expense of large aberrations. A compromise solution was chosen in one embodiment: f₃ = 36,37 mm and f₄= 8,76 mm.

[0170] Both subsystems (i.e. the coupling collimator 12i and the coupling condenser 122) of the coupling telescope (coupling optics 12) are designed as classic achromats in the form of cemented achromatic doublets. This specifically allows chromatic aberrations and spherical aberrations to be efficiently corrected.

[0171] The distance between the two subsystems of the coupling optics 12 is selected such that the inner focal planes coincide. This turns the coupling optics 12 into a telescope that is characterized by an infinite focal length. The latter is also called “afocal”. An aperture diaphragm / coupling aperture stop 23 is placed in the common focal plane FP12i of both subsystems, which ensures the telecentricity of the coupling optics 12 on both sides. The following relationship applies to the diameter D2 of the aperture diaphragm 23 and the fiber-side numerical aperture NAF:

[0172] D2 = 2 × f4× NAF= 4,4mm

[0173] The actual effective aperture diaphragm composed of the overall system that comprises collectors (and collimator and condenser) 19₁, 19₂, 21₁, 21₂, 12₁, 12₂, relay 21 and coupling optics 12 is not located in the coupling optics 12 but in the upstream relay 21. For this reason, the diameter D2 according to an embodiment of approx. 5mm is chosen to be slightly larger than the nominal value (of 4.4mm) calculated above. The aperture diaphragms 22, 23 of the relay 21 and coupling optics 12 are optically conjugated. This means that there is an image-to-image relationship between the two. The aperture diaphragm 23 of the coupling lens does not act as an aperture diaphragm for the entire system in the strict sense, but “only” as a highly efficient false light diaphragm.

[0174] As already mentioned, the inner focal planes of the two subsystems coincide. The outer focal planes contain the sample or the input facet 17i of the fiber bundle 17. This arrangement is referred to in the literature as a 4f system.Relay 21 according to an embodiment

[0175] The relay 21 projects a locally homogeneously illuminated field diaphragm 9i, 92 onto the sample 5 in the cuvette 4.

[0176] The exit pupil and the exit hatch correspond exactly to the entrance pupil and the entrance hatch of the coupling optics 12.

[0177] The relay 21 is designed as a telescope. In contrast to the coupling optics 12, the magnification may be chosen arbitrarily. This is an advantage if mi = -1 is selected. This renders the telescope symmetrical and both subsystems can be constructed from identical parts. In addition, the aberrations coma, distortion and lateral chromatic aberration of both subsystems compensate each other to exactly zero.

[0178] Due to the symmetry, the diameter of the field diaphragm must be 2,5mm in this embodiment. The same considerations apply to the dimensioning of the focal lengths fi and fz of the relay 21 as for the coupling optics 12. As a compromise, 16,35mm was chosen in each case for this embodiment. Here as well, both subsystems were designed as classic achromats. Accordingly, the same considerations apply here as with the coupling optics 12.

[0179] The aperture diaphragm of the overall system is located exactly in the symmetry plane FP2h of the relay 21. The following applies to the numerical aperture NAK at the location of the cuvette 4: NAK= NAF× |m₂|0,06= 0,24× 0,25= |

[0180] This results in the diameter of the aperture diaphragm / 22 Köhler aperture stop 22:

[0181] D1 = 2 × f₂ × NAK= 2,0mm

[0182] Collector 19 according to an embodiment

[0183] The two collectors 19₁, 19₂ should illuminate the two field diaphragms 9₁, 9₂ locally and homogeneously. The beam diameter at the location of the cuvette 4 is 2,5mm in this embodiment. Since mi = -1 applies to the relay 21, the diameter DF of the field diaphragms must apply in this embodiment:

[0184] DF = 2,5mm

[0185] The focal length fs of the collector 19i in the LED branch was selected (being representative for both branches):

[0186] fs = 7mm

[0187] For the numerical aperture NAs of the collector 19i, this results in

[0188] NA5= DF / (2 × f5) = 0,18This numerical value also allows the collector 19i to be designed as a simple cemented achromatic doublets. In the design, attention is paid to the correction of chromatic aberration, spherical aberration and sine condition.

[0189] The first subsystem of the relay together with the collector in turn forms a 4f system that maps the white LED into the aperture diaphragm of the overall system. This property defines Kohler illumination. The following applies to the magnification mo:

[0190] |m₀| = f₁ / f5= 2,34

[0191] The image of the aperture diaphragm at the location of the LED is a circle for its diameter DLED applies:

[0192] DLED= D₁ / |m₀|0,86= 1mm

[0193] This numerical value allows the use of a commercially available “white” LED chip (with chip level conversion), which typically has a square format with an edge length of approx. 1mm (or moderately larger).

[0194] Köhler illumination concept and Abbe sine condition

[0195] Critical Illumination is a simple concept for a lighting / illumination system, in which the light source is optically conjugated with the specimen / sample 5. This, of course, requires a light source having a specific radiance [W / cm2] that is spatially sufficiently constant. Obviously, classical light sources, such as a light bulb (filament!), do not meet this requirement at all. August Köhler recognized that one can still use light sources with an inhomogeneous specific radiance together with a collector optic for spatially homogeneous illumination of a sample 5. As will be shown further below, perfect spatially homogeneous illumination is achieved under two conditions:

[0196] 1. The light source has a Lambertian emission characteristic (in angle space)

[0197] 2. The collector optic satisfies the sine condition according to Ernst Abbe

[0198] By definition, the radiance L of a light source is:

[0199]

[0200] wherein:

[0201] φ: Optical flux

[0202] β, φ: Polar angle, azimuth angle in spherical coordinates

[0203] dA, dΩ: Surface element, solid angle element

[0204] Specifically, for a Lambertian light source in angle space, the following applies:

[0205] L(β, φ) = L = const.In Köhler illumination, the spatial dependency of the radiance does not play a role. Accordingly, one can simplify by assuming it to be constant (without limitation) and integrate Equation (1) over (A):

[0206]

[0207] On the source side, that is, before the collector, it follows from equation (2) for the differential flux through a differential solid angle element in spherical coordinates:

[0208] (3) dφ = A · L · cos(β) · dΩ = A · L · cos(β) · sin(β) · dβ · dφ

[0209] In the next step, the differential flux through a surface element in the focal plane of the collector, which faces away from the light source, is considered. In cylindrical coordinates, the following applies:

[0210] (4) dφ = E · r · dr · dφ

[0211] with

[0212] E: irradiance in the focal plane

[0213] r: distance of the surface element from the optical axis

[0214] Equating (3) and (4) results in:

[0215] (5) A · L · cos(β) · sin(β) · dβ = E · r · dr

[0216] According to Abbe's sine condition, the following applies:

[0217] (6) r / f = sin(β)

[0218]

[0219] Differentiating (6) results in:

[0220] (7) dr = f · cos(β) · dβ

[0221] Substituting (6) and (7) into (5) finally results in:

[0222] (8) E = A · L · 1 / f² The irradiance E in the rear / upstream focal plane is given by the constants A, L and f. In particular, E does not depend on the coordinates r and (p. This is what was to be proofed.

[0223] Fig. 8 shows the technical implementation of the collector (C) as a simple cemented achromatic doublet. The primary light source is located at the intersection point of the dark grey and light grey rays on the left, which are collimated (parallel) to each other. Rays with the same inclination on the input side of the collector have the same intersection point in the rear focal plane (RFP) on the output side of the collector (C).The previously formulated sine condition (Equation 6) simply means that the height of these intersection points y above the optical axis (on the right) is linearly proportional to the sine of the beam inclination (on the left). The proportionality constant is the focal length f. The sine of the beam inclination is referred to as the numerical aperture.

[0224] In a more specific sense, the focal length is a paraxial quantity, which by definition is a constant and thus does not describe aberrations. The sine condition formulated by Ernst Abbe allows for a generalization of the focal length in terms of a non-paraxial, aberration-affected quantity. Fig. 9 illustrates this in detail. The focal length is both a function of the numerical aperture and a function of the wavelength, and is therefore not constant.

[0225] The dependency of the focal length of the collector on the wavelength and the numerical aperture should be minimized. This will ultimately be rewarded with a position-independent irradiance in the rear focal plane of the collector, provided a Lambertian light source is used on the input side. In a Köhler illumination system, the radial extent of the illumination field in the rear focal plane of the collector is limited by a suitable aperture (field diaphragm). The corresponding illumination field can be considered a secondary light source, which, due to its constant specific radiance, can be used to implement a critical illumination device.

[0226] Fig. 10 shows the rays from a Lambertian light source and the double-lens collector (C) with a circular aperture in its rear focal plane. The irradiance distribution inside the aperture is shown in false colors.

[0227] Fig. 11 shows the distribution of the irradiation intensity within the illumination field diaphragm in detail, coded in false colors. The uniformity is apparently excellent and is limited solely by the radiation statistics of the Monte Carlo analysis. This indicates a proper technical implementation of the collector. Whenever possible, LEDs are used in scientific lighting systems nowadays. Good reasons for this include, among others, lifespan, cost, efficiency, heat dissipation, and size. It is particularly noteworthy that LED chips without primary optics exhibit a Lambertian radiation characteristic in a very good approximation. In combination with sufficiently sinus-corrected collector optics, a high-quality lighting system can thus be easily realized.

[0228] Referring again to the field setting of the optical analyzer: Fig. 2 is a schematic drawing of the optical analyzer system comprising the optical arrangement of Fig. 1 in the field setting to display conjugate field planes according to an embodiment.

[0229] In a somewhat simplified embodiment with only one lights source: Fig. 7 is a strongly simplified scheme of an optical arrangement displaying the conjugate field planes according to an embodiment and displaying the conjugate aperture planes according to an embodiment.For the field settings of Fig. 2 and Fig. 7: Foci are in the field planes. In Fig. 2, primary sources and collectors are not shown.The field planes are in: the field stops 9, 9i, 92, the cuvette 4, the coupling exit 14 / the optical fiber entrance 17i.

[0230] Both, relay 21 and coupling optics 12 generate field planes FP2h and FP12i, respectively.

[0231] The image scale of the relay is 1:1 in the shown embodiments. The size of a field stop 9, 9i, 92 defines the beam diameter in the cuvette 4.

[0232] The coupling optics 12 reduces the field size well-defined: The beam modestly overfills the optical fiber arrangement 17 comprising one or more optical fibers 17s in the spatial domain and in the angular domain. The size of the aperture stop 22 of the relay 21 defines the NA at the optical fiber entrance 17i.

[0233] The difference between the optical arrangement 1 according to an embodiment and a classical microscope are: A classical microscope enlarges on the imaging side, while the coupling optics 12 reduce the image. In a microscope, a typical image sensor (CCD or CMOS) is located at the receiving plane which corresponds to the position of the coupling exit 14 of the coupling optics 12. In the optical arrangement 1 according to an embodiment, there is a densely packed fiber bundle / optical fiber arrangement 17 comprising one or more optical fibers 17s at this position, comprising for example seven optical fibers 17s.

[0234] In Fig. 7, the yellow beam path corresponds to a pupil beam path: The yellow beam, represented by only 2 rays, starts in the light source 10, e.g. the center of the neon lamp. There are exactly two further intersection points of the yellow rays, namely in the aperture stop 22 of the Köhler illumination optics 6 and in the aperture stop 23 of the coupling optics 12. The light source 10 is therefore optically conjugated to all aperture stops 22, 23.

[0235] The pink beam path corresponds to a field beam path: The pink beam, represented by only 2 rays, starts in the center of the field stop 9. There are exactly two further intersection points of the pink rays, namely in sample 5 and in the coupling focus point 16 (and 14, 15). The intersection points of the pink rays therefore mark the position of the hatches (German: “Luke”). The field stop 9 corresponds to the entrance hatch, the image of the sample in the sample plane 15 corresponds to the exit hatch. Another hatch is located in the center of the cuvette 4.

[0236] An important characteristic is the fact that the position, where the pink rays (field beam path) are collimated, is the position of an intersection point of the yellow rays (pupil beam path) and the position, where the yellow rays (pupil beam path) are collimated, there is an intersection point of the pink rays (field beam path).

[0237] It is generally to be noted that in textbooks sometimes a different subdivision of a Köhler illumination optics is used, namely a collector 19 and condenser 21. In the present disclosure, theKöhler illumination optics is divided it into collector 19 and relay 21. The subgroups of the relay 21 are collector 21_1 and condenser 21_2.

[0238] Fig. 12 is a scheme of an optical analyzer system comprising an optical arrangement in the pupil setting to display conjugate aperture planes according to an embodiment with marked positions for explanation of the difference to the Köhler approach.

[0239] The optical analyzer system of Fig. 12 is characterized in that:

[0240] The white LED uniformly illuminates the field stop via the collector. The same applies for the neon bulb. The relay images the field stop to the center plane of the cuvette. The coupling optics images the center plane of the cuvette to the entrance of the fiber bundle. Both primary sources are imaged to the aperture stop of the relay and to the aperture stop of the coupling optics. The pupil setting is characterized in that the Foci are in the pupil planes.

[0241] In position A, where the embodiment of the invention may provide a neon bulb, a classical bright field microscope according to the Köhler approach provides a primary lamp.

[0242] In position B, a classical bright field microscope according to the Köhler approach provides a collector.

[0243] In position C, a classical bright field microscope according to the Köhler approach provides a field stop.

[0244] In positions D, E, F and G, a classical bright field microscope according to the Kohler approach does respectively not provide a reference detector, a beam splitter, a white LED and a collector, as the embodiment of the invention does.

[0245] In position H, a classical bright field microscope according to the Köhler approach provides an aperture stop.

[0246] In position I, where the embodiment of the invention may provide a relay, a classical bright field microscope according to the Köhler approach provides a condenser.

[0247] In position J, where the embodiment of the invention may provide a cuvette, a classical bright field microscope according to the Köhler approach provides a slide with a specimen.

[0248] In position K, where the embodiment of the invention may provide a coupling optics, a classical bright field microscope according to the Köhler approach provides a microscope lens.

[0249] In position L, where the embodiment of the invention may provide a fiber, a classical bright field microscope according to the Köhler approach provides a camera chip.

[0250] In position M, a classical bright field microscope according to the Köhler approach provides an aperture stop.Fig. 13 is a scheme to illustrate the optical analyzer system according to the embodiment with respect to the general principle of the Köhler illumination approach shown in Fig. 12. The upper illustration of Fig. 13 shows the illumination beam path and conjugated planes are marked using the (lower) purple bar underneath the illustrations. The lower illustration of Fig. 13 shows the imaging beam path and conjugated planes are marked using the (upper) red bar underneath the illustrations.

[0251] Plane C in Fig. 13 may correspond to the "fiber position" in the upper image. The beam bundles in Fig. 12 show the conjugate planes for imaging the light source. This corresponds to the upper illustration of Fig. 13. The lower illustration of Fig. 13 additionally shows the conjugate planes for the fields.

[0252] The embodiment of illustration of Fig. 12 is different from the Köhler illumination approach of Fig. 13 in that it is setup in each stage of development in a telecentric design for both beam paths (field and pupil). This is primarily due to the implementation with pairs of achromats (doublets), which are designed for finite-infinite imaging. The embodiment of illustration of Fig. 12 is characterized in that the telecentricity is given in plane " C" or "fiber position". This allows adjusting the beam characteristics and the acceptance characteristics of the fiber bundle at this point. Therefore, the coupling optics comprises a coupling aperture stop configured to define a telecentric exit pupil at the coupling exit.

[0253] Telecentricity is a specific pupil position (= infinity) that is not required in microscopy in the image plane and is not implemented in the typical bright field microscopy using the Köhler illumination approach.

[0254] Typically the goal of a microscope is providing a magnified image for a sensor or a human eye. The angle at which light hits the sensor is less relevant to image sharpenss.

[0255] On the contrary, one goal of the present invention or at least an embodiment thereof is maximizing the Signal-to-Noise Ratio (SNR) by matching the etendue and the numerical aperture (NA) of the beam to the specific acceptance characteristics of an optical fiber bundle.

[0256] Reference list

[0257] 1 Optical arrangement

[0258] 2 Light

[0259] 21First light, specifically white light

[0260] 22Second light, specifically neon light

[0261] 2’ Sample light, i.e. first light and / or second light after passing the Köhler illumination optics and the sample

[0262] 3 Sample space, specifically cuvette holder

[0263] 3’ Sample planeCuvette

[0264] Sample

[0265] Köhler illumination optics

[0266] Köhler entrance

[0267] i First Köhler entrance, specifically for receiving white light

[0268] Second Köhler entrance, specifically for receiving neon light Kohler exit

[0269] Field stop

[0270] 91First field stop, specifically for being passed by the white light92Second field stop, specifically for being passed by the neon light

[0271] 10 Light source

[0272] 101First light source, specifically white light source, such as white light LED102Second light source, specifically neon light source, such as neon light bulb11 Image of the at least one field stop in the sample plane

[0273] Coupling optics

[0274] 121coupling collimator

[0275] 122coupling condenser

[0276] 13 Coupling entrance

[0277] Coupling exit

[0278] 15 Image of the sample in the sample plane

[0279] 16 Coupling focus point

[0280] 17 Optical fiber arrangement comprising one or more optical fibers

[0281] 171Optical fiber entrance

[0282] 172Optical fiber exit

[0283] 173Single optical fiber

[0284] 18 Optical analyzer

[0285] 19 Köhler collector

[0286] 191First Köhler collector, specifically for being passed by the white light192Second Köhler collector, specifically for being passed by the neon light20 Beam splitter

[0287] 21 Relay

[0288] 211Relay collimator

[0289] 212Relay condenser

[0290] 22 Köhler aperture stop

[0291] 23 Coupling aperture stop

[0292] 24 Reference detector

[0293] 25 Supporting structure

[0294] 26 Core of the optical fiber27 Cladding

[0295] 28 Insulating

[0296] 100 Optical analyzer system

[0297] 500 Oximeter module

[0298] 501 Illumination device

[0299] 502 Optical fiber bundle

[0300] 502i Entrance of the optical fiber bundle

[0301] 5022Single optical fibers

[0302] 503 Grating spectrometer

[0303] 504 White LED

[0304] 505 Neon lamp

[0305] 506 Lens

[0306] 507 Diode

[0307] 508 Beam splitter

[0308] 509 Sample

[0309] 510 Cuvette

[0310] 511 Hemolysing unit

[0311] 512 Peltier

[0312] 513 PD array

[0313] 514 Optical path

[0314] C Collector

[0315] FP121Focus point of the coupling collimator

[0316] FP211Focus point of the relay collimator

[0317] FP212Focus point of the relay condenser, i.e. relay focus pointLL Lambertian light source

[0318] R Rays

[0319] RFP Rear focal plane and / or back focal plane

Claims

Patent Claims1. Optical arrangement (1) for efficient coupling of a sample light (2’) into an optical analyzer (18) of an IVD instrument, the optical arrangement (1) comprising:a Köhler illumination optics (6) for receiving a light (2) emitted from at least one light source (10) and comprising at least one field stop (9);a transmission sample space (3) for receiving a sample (5); anda coupling optics (12) comprising a coupling exit (14) for being coupled to the optical analyzer (18),wherein the Köhler illumination optics (6), the transmission sample space (3) and the coupling optics (12) define at least partially an optical pathway for the light (2) received by the Köhler illumination optics (6), and the Köhler illumination optics (6) being configured to illuminate with the light (2) at least partially a sample (5) when being received by the transmission sample space (3) and to generate in the sample (5) an image (11) of the at least one field stop (9), and wherein the coupling optics (12) is configured to receive the light (2) which is transmitted through the sample (5) being the sample light (2’) and to project, together with the image (11) of the at least one field stop (9), an image (15) of the sample (5) at least partially onto the coupling exit (14), wherein the coupling optics (12) comprises a coupling aperture stop (23) configured to define a telecentric exit pupil at the coupling exit (14).

2. The optical arrangement (1) of claim 1, wherein the Köhler illumination optics (6) comprises a 22 Köhler aperture stop (22) that is configured to define a numerical aperture of the light (2) received by the Köhler illumination optics (6).

3. The optical arrangement (1) of claim 1 or 2, wherein the coupling optics (12) corresponds to a de-magnifier specifically being configured to project the image (15) of the sample (5) at least partially onto the coupling exit (14) as an image of a reduced size.

4. The optical arrangement (1) of any of the preceding claims, wherein the Köhler illumination optics (6) is configured for receiving the light (2) comprising a first light (2, 2i) emitted by a first light source (10, 10i) and a second light (2, 22) emitted by a second light source (10, 102),specifically, wherein the optical arrangement (1) comprises the first light source (10, 101), specifically a white light source, such as a white light LED; and / or wherein the optical arrangement (1) comprises the second light source (10, 102), specifically a neon source, such as a neon bulb.

5. The optical arrangement (1) of claim 4, wherein the at least one field stop (9) comprises: a first field stop (9, 9i) positioned in the optical pathway of the first light (2, 2i); and / ora second field stop (9, 92) positioned in the optical pathway of the second light (2, 22), specifically, wherein the Köhler illumination optics (6) comprises a beam splitter (20) positioned in the optical pathway behind the first field stop (9, 9i) and the second field stop (9, 92) for superimposing the first light (2, 2i) with the second light (2, 22).

6. The optical arrangement (1) of any of the preceding claims,wherein the Köhler illumination optics (6) is configured to illuminate the sample (5) uniformly and / or homogeneously, specifically with the first light (2, 2i) and / or the second light (2, 22), and / or wherein the coupling optics (12) is configured to project, together with the image (11) of the at least one field stop (9), an image (15) of the sample (5) uniformly and / or homogeneously onto the coupling exit (14).

7. The optical arrangement (1) of any one of the claims 4 to 6,wherein the Köhler illumination optics (6) comprises:a first Köhler collector (19, 191), positioned in the optical pathway of the first light (2, 21), specifically positioned behind the first light source (101) and in front of the beam splitter (20); and / ora second Köhler collector (19, 192), positioned in the optical pathway of the second light (2, 22), specifically behind the second light source (102) and in front of the beam splitter (20); and / or a relay (21) comprising a relay collimator (211) and a relay condenser (212) positioned in the optical pathway of the first light (2, 21) and / or the second light (2, 22), specifically behind the beam splitter (20); and specificallythe Köhler illumination optics (6) comprising the 22 Köhler aperture stop (22) positioned in the optical pathway of the first light (2, 21) and / or the second light (2, 22) between the relay collimator (21i) and the relay condenser (2h), specifically in a focus point (FP2h) of the relay collimator (2h).

8. The optical arrangement (1) of any one of the preceding claims, further comprising: an optical fiber arrangement (17) for indirectly coupling the coupling optics (12) to the optical analyzer (18), the optical fiber arrangement (17) comprises an optical fiber entrance (171) configured for being coupled to the coupling exit (14) of the coupling optics (12), an optical fiber exit (172) configured for being coupled to the optical analyzer (18) and a plurality of optical fibers (173) being arranged in a circle packing at the optical fiber entrance (171) and extending from the optical fiber entrance (171) to the optical fiber exit (172).

9. The optical arrangement (1) of claim 8,wherein the plurality of optical fibers (173) comprises and / or corresponds to an odd number, specifically to one, three or seven fibers; and / orwherein the plurality of optical fibers (173) are polygonally arranged at the optical entrance (171) by a tightest packing arrangement, specifically forming a hexagonal arrangement geometry; and / or wherein the plurality of optical fibers (173) are linearly arranged at the optical exit; and / or wherein the fiber arrangement comprises a supporting structure configured to support the geometric arrangement of the plurality of optical fibers.

10. The optical arrangement (1) of any one of the preceding claims, wherein the sample space (3) is positioned directly between the Köhler illumination optics (6) and the coupling optics (12).

11. The optical arrangement (1) of any one of the preceding claims 2 to 10, wherein the coupling optics (12) comprises a coupling collimator (121) and a coupling condenser (122) and specifically wherein the coupling aperture stop (23) is positioned between the coupling collimator (121) and the coupling condenser (122), specifically in a focus point (FP121) of the coupling collimator (121) and / or wherein the coupling optics corresponds to a singular functional unit configured to match the specific etendue of a spectrometer.

12. The optical arrangement (1) of any one of the preceding claims, wherein the sample space (3) comprises a cuvette (4) for receiving the sample (5) and / or the sample space (3) is configured to receive a cuvette (4) for receiving the sample (5).

13. Optical analyzer system (100) of an of an IVD instrument comprising the optical arrangement (1) of any one of the preceding claims and the optical analyzer (18).

14. The optical analyzer system (100) of claim 13, wherein the optical analyzer (18) comprises at least one of: a photometer, a spectrometer, specifically a Raman spectrometer, an IR spectrometer, a UV-vis spectrometer, a fluorescence spectrometer.

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