Illumination system having light guides with diffuser elements that emit substantially radially, and manufacturing method thereof

Abstract

To provide an illumination system, in particular for medical technical therapeutic and / or diagnostic systems.SOLUTION: An illumination system (1) includes at least one laser light source (10) and a light guide (30) which, at a proximal end, is connectable and / or assignable to the at least one laser light source. The illumination system has, at a distal end of the light guide, a diffuser element (40) which has a substantially radial, spherical emission characteristic. The diffuser element comprises at least one diffuser main body. The diffuser main body comprises an inorganic material, in particular a glass, a glass ceramic, a glass-like material, or a composite material of these materials, and advantageously at least one scattering element. A surface of the at least one diffuser main body is pore-free and smooth. Such an illumination system can be used in photodynamic therapy (PDT), photoimmunotherapy (PIT), and ophthalmic and dental fields.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The invention relates to an illumination system, in particular for a medico-technical treatment and / or diagnostic system, comprising at least one laser light source and a light guide connectable and / or assignable to said at least one laser light source at its proximal end and comprising a diffuser element at the distal end of said light guide. The invention further relates to a method for manufacturing said illumination system.

[0002] Such lighting systems are increasingly used in the medical field, where the following main applications can be classified: Photodynamic therapy (PDT) and / or photoimmunotherapy (PIT) to treat tumors, Endovenous Laser Therapy (EVLT) to treat varicose veins, Laser Interstitial Thermotherapy (LITT), and Other applications, especially in the dental, ophthalmological and dermatological fields.

[0003] Photodynamic therapy (PDT) is a minimally invasive treatment for various cancer diseases. PDT refers to a method for treating tumors and other tissue changes (such as angiogenesis) using light in combination with photoactivatable substances. At the beginning of the treatment, light-sensitive substances called photosensitizers are injected intravenously into the patient's bloodstream, where they accumulate in or on the cancer cells. These natural light substances accumulate in the tumor cells and cause significant photosensitivity there. For this purpose, several cannulas (usually up to eight) can be punctured into the tumor tissue during PDT treatment, into each of which a light guide with a diffuser element is introduced, whereby the diffuser element must be positioned as spatially distributed as possible throughout the tumor tissue. The laser light, which usually has a wavelength in the visible spectral range, for example green light with a wavelength of 532 nm or red light with a wavelength of 690 nm, is in-coupled via the light guide into the diffuser element so that the tumor tissue is illuminated as uniformly as possible from the inside. During this process, aggressive oxygen radicals are formed in these cells, which selectively destroy the tumor cells. In contrast to diseased cells, healthy cells are not affected by this chemical reaction. The detailed mechanism of action is described inter alia in “Photodynamic Therapy of Cancer”, Cancer Medicine, 2003.

[0004] In the case of photoimmunotherapy (PIT), photosensitizers are attached to antibodies, allowing the drug to be more selectively released into tumor tissue. The antibodies are specific to proteins present on the surface of the tumor, so they act specifically on the tumor. Light is then irradiated onto the tumor, causing its destruction. Ideally, the photosensitizer attached to the antibody reaches the most sensitive part of the tumor cell, such as the lysosomes, which contain digestive enzymes. When the lysosomes are destroyed, the release of enzymes digests the cancer cells. This allows for a more selective and focused therapeutic effect, and also allows for the use of lower doses of photosensitizers and lower doses of light.

[0005] A distinction is made here between cylindrical diffusers, with a typical effective length of 10-50 mm, spot diffusers, which generate a forward-directed cone of illumination, and point emitters with radial emission. In the case of cylindrical diffusers, it is important that in the operating condition, especially the transverse emission of the diffuser element, is as uniform as possible over its entire length. This requires that not only is the radiation intensity the same within the uniformity requirements in the axial direction, i.e. at all points along all lines from the proximal end to the distal end in the longitudinal axis direction, but also that the radiation intensity is the same within the uniformity requirements in the radial direction, i.e. at all points on all circumferential lines along the longitudinal axis, so that these diffusers almost act as Lambertian emitters. At the same time, it is also desirable in many applications to have a high scattering efficiency in order to input as little heat as possible into the tissue. However, there are also applications where a certain amount of heat input is necessary.

[0006] In the case of a diffuser configured as a point emitter, it is particularly important that the light is distributed evenly throughout the spherical space.

[0007] A known example is a diffuser element consisting of a thin silicone cylinder in which scattering particles in the form of titanium oxide nanoparticles are embedded. DE 10129029 A1 describes a flexible device for thermally occluding biological tissue with laser radiation, which comprises a light guide for guiding the laser radiation, the distal end of which is surrounded by a jacket tube transparent to the laser radiation, which protrudes beyond the fiber end and whose volume located before the fiber end is filled with a silicone matrix in which scattering particles are embedded, a plastic matrix preferably made of silicone, which is mixed with non-scattering particles, preferably made of silicon dioxide, with a diameter of a few nm, preferably in a concentration range of 1-10%, and the distal end of the jacket tube is closed by an end member transparent or impermeable to the laser radiation.

[0008] However, producing them with sufficient radiation uniformity is very cumbersome and expensive: agglomerates of scattering particles often produce radiation spots whose intensity is significantly above average: moreover, only low laser powers can be applied.

[0009] These light guides with diffuser elements are usually used only once and are discarded after each treatment. Thus, a certain cost-push inflation occurs with respect to production costs. Intensive consideration is therefore also given to reusable solutions. Such solutions must be processable in accordance with the relevant known standards, e.g. disinfectable and / or sterilizable. In this case, the treatment methods include, in particular, cleaning / disinfecting methods with strongly basic solutions and sterilization by autoclave at temperatures up to 135 °C and a typical steam pressure of about 3 bar. Usually, tens or hundreds of such treatment cycles are envisaged. This places great demands on the heat resistance, chemical resistance and also on the hydrolysis resistance. Therefore, the approach of light guides and diffusers made of glass or quartz glass fibers is particularly suitable.

[0010] In the case of EVLT, the treating physician inserts a catheter into the affected vein through a small puncture. This catheter serves as a guide rail for the venous laser. The inner wall of the blood vessel is then heated strongly by the targeted lateral emission of laser energy by a diffuser, which collapses and closes the vein. This prevents the abnormal backflow of venous blood. As a result, the vein hardens, degenerates and can be decomposed by the body. In this case, so-called ring fire or double ring fire systems are usually used as the emitting element at present. The laser light is applied radially to the tissue surrounding the vein in the form of a relatively sharply demarcated ring light or double ring light. In this case, the light guide with the emitting element is often manually drawn through the vein section to be treated at as constant a speed as possible for the sake of uniform treatment, which makes the application difficult, since in the case of neglect of checking or in the case of very long dwell times, further cell damage may occur at certain points.

[0011] In this case, a cylindrical diffuser as used in PDT applications would be advantageous. However, significantly higher laser powers are required for EVLT treatment. For example, the laser power is generally 10-50 W for wavelengths in the NIR range, i.e., about 800 nm to 1480 nm, which is currently provided by diode lasers (e.g., 810 nm, 940 nm or 1480 nm) or Nd:YAG lasers (1064 nm). Longer wavelengths, such as 2 μm, are now also established for EVLT treatment. For example, Tm:YAG lasers (1.9 μm) and Ho:YAG lasers (2.1 μm) are used. Due to the absorption properties of the tissue, lower laser powers are required at these wavelengths, generally less than 10 W. However, in this case already the use of quartz glass light guides is necessary, especially for the delivery of the laser light.

[0012] LITT is a minimally invasive method used for localized tumor destruction. In this case, the tumor is punctured under imaging control (e.g., ultrasonography / MRT) and one (or several) laser fibers are introduced into the tumor center, which is then occluded by thermal energy. Here, in particular, a Nd:YAG laser (1064 nm) and a diffuser tip applicator are used. The laser power is about 5-8 W (see, for example, “Laserinduzierte Interstitielle Thermotherapie (LITT) bei malignen Tumoren”, BAEK and KBV 01 / 2002).

[0013] Further diffuser approaches are known from the following literature and can be divided into four categories: volume scattering diffusers, fibers provided with scattering particles, diffusers produced by laser processing and diffusers formed from laterally emitting fibers.

[0014] Volume scattering diffusers are described, for example, in EP 3184885 A1. There, a diffuser is described at the end of an optical fiber made of quartz glass, and for producing the diffuser, it is provided that a scattering material is applied to the fiber distal end of the optical fiber and hardened to form the diffuser. The application of the scattering material includes the steps of (a) providing a SiO2 granule containing amorphous SiO2 particles and at least 90% of which is made of SiO2, (b) providing a glass hollow body having a cavity wall surrounding an open cavity to the outside, (c) forming a layer of SiO2 granules in the cavity and introducing a fiber end into the cavity so that at least a part of the fiber end protrudes into the layer, and (d) hot compressing the layer to form a porous sintered material made of at least 90% by weight of SiO2, which is at least partially surrounded by a glass jacket. The disadvantage of such an approach is that such a volume scattering approach is accompanied by a large exponential falloff in intensity. Furthermore, porous materials are undesirable in terms of their processability in medical applications, and the scattering effect can be significantly altered or even negated by the penetration of body fluids into the scattering porous material during treatment.

[0015] US Patent No. 6,810,184 describes an approach using nanoporous silicon dioxide coated optical fiber to fabricate a fiber with an integrally formed diffusing tip that can be fused with other fibers. The disclosed diffusers can be fabricated cylindrical with light diffusing along its length, spherical with light radiating outward in a spherical pattern, or customized to illuminate irregular surfaces or volumes. Graded index and step index properties can also be achieved.

[0016] EP 2 062 077 A1, US 2009 / 0204111 A1 and DE 10 2015 119 875 A1 describe diffusers for the production of which a structure is introduced or applied into or onto the fiber by means of a laser.

[0017] EP 2062077 or WO 2008 / 024397 describe a diffuser for outputting optical energy at a particularly high power density at the distal end of at least one optical fiber to a treatment site, the diffuser being a section of a predetermined length of the distal end of at least one optical fiber, and scattering centers arranged within the section of a predetermined length of the distal end of the optical fiber, by means of which a portion of the input optical energy is radially emitted to the treatment site. It is provided that the scattering centers are arranged in a predetermined length of the fiber core or in or near the interface between the fiber core and the cladding. The scattering centers are defects in the fiber core, for example nanocracks or nanovoids, which generate a local refractive index difference either in the core or in or near the interface between the core and the cladding. The scattering centers may be scattering particles contained in the core or in the cladding of the core. For example, the distribution and / or size of the aforementioned nanocracks and nanovoids, in addition to being cumbersome to implement and difficult to control, can also adversely affect the susceptibility of components to breakage. Furthermore, in any of the aforementioned approaches, it should be considered that in embodiments where the scattering centers are sufficiently uniform, the lateral emission falls off exponentially, or the distribution is non-uniform, resulting in lateral emission that does not have the required uniformity.

[0018] US 2009 / 0204111 A1 describes a laser delivery system comprising an optical fiber having (i) a core and a cladding layer covering at least a portion of the core, the cladding layer having a lower refractive index than the core, and (ii) a non-feature portion and a feature portion having a feature that causes light to radiate radially from the feature portion to provide a desired radial light output pattern, wherein it is provided that the feature is selected from the group consisting of a spiral structure, a radial cut, an axial cut, and combinations thereof.

[0019] DE 102015119875 A1 describes an optical waveguide comprising an optical waveguide core and a region within the optical waveguide in which micro-modifications are arranged and the arrangement of the micro-modifications is ordered. A method for introducing micro-modifications into the optical waveguide comprises the steps of (a) fixing the optical waveguide to a holder, the optical waveguide and / or the holder being movably mounted, (b) focusing high-energy radiation at a focal position, the focal position being positionable within the optical waveguide, the radiation being generated by a radiation source in a pulsed operation and a focusing device for focusing the high-energy radiation being movably mounted, and (c) moving the focal position through the optical waveguide, where the movement of the focal position within the optical waveguide is selected based on the repetition rate.

[0020] WO 2017 / 103796 describes a further illumination system for emitting light, where the illumination system is a light guide connected to an optical scattering element.

[0021] A further document of the applicant, PCT / EP2018 / 076487, describes an illumination system, in particular for medical-technical treatment and / or diagnostic systems, which comprises at least one laser light source and a light guide connectable and / or assignable at its proximal end to the at least one laser light source, and at the distal end of the light guide, a cylindrical diffuser element with a longitudinal axis, which extends perpendicularly into the diffuser element to the input coupling surface of the light guide, which in its operating state emits light over its effective length transversely to the longitudinal axis. Here, the diffuser element comprises at least one diffuser body including at least one scattering element, advantageously the at least one scattering element extending along the longitudinal axis of the diffuser body. With such an arrangement, it is possible to achieve a uniform intensity distribution of the radiation in the transverse direction along the diffuser length in the operating state. However, this requires a diffuser body of relatively large extent in the longitudinal direction.

[0022] The object of the present invention is therefore to provide a diffuser for an illumination system, in particular for a medical-technical treatment and / or diagnostic system, which is more compact than an elongated diffuser and which radiates uniformly, ideally spherically, into space or into the surrounding tissue, essentially as a point emitter.

[0023] It would therefore be advantageous to provide a compact diffuser element in which the disadvantages of the approach described at the beginning, such as porosity and low laser resistance, are significantly reduced. It would be advantageous if this diffuser element could emit uniformly with high efficiency. Furthermore, it is an object of the present invention to provide a method suitable for its cost-effective manufacture.

[0024] Disclosure of the Invention The problem of the present invention is solved by the subject matter of the independent claims, advantageous embodiments can be taken from the respective dependent claims, the further disclosure of the specification and the drawings.

[0025] Thus, in a first aspect, the subject of the present invention is an illumination system, in particular an illumination system for a medico-technical treatment and / or diagnostic system, comprising at least one laser light source and a light guide connectable and / or assignable at its proximal end to the at least one laser light source and at the distal end of the light guide a diffuser element having a substantially radially spherical radiation characteristic, the diffuser element comprising at least one diffuser body comprising an inorganic material, in particular glass, glass ceramics, glass-like material or a composite material made of the aforementioned materials and advantageously at least one scattering element, the surface of the at least one diffuser body being free of pores and smooth.

[0026] The term "pore-free and smooth" is understood to mean that the surface quality of the diffuser body is very high, corresponding to a flame-polished surface quality. This flame-polished surface quality of the diffuser body can be caused by the material and processing of the diffuser body itself, for example when glass or glass ceramics are selected as materials. However, the flame-polished or equivalent surface quality, at least with respect to the pore-free parameters of the diffuser body, can also be caused by a jacket, and at least one diffuser body advantageously includes a jacket at least partially or regionally, which at least partially or regionally or completely surrounds the diffuser body and forms a pore-free and smooth surface.

[0027] As a result, the pore-free and smooth surface of the diffuser becomes substantially dense, which has the advantage of reducing the reaction with the liquid or reducing the influence of the working liquid on the radiation behavior.

[0028] An element which can preferably cause scattering during operation is referred to below as a scattering element. A scattering element comprises a scattering region, which may comprise a volumetric region, which causes scattering. The scattering itself is caused by at least one scattering center in the scattering region. The scattering center may comprise, for example, particles or pores. Here, it is provided in particular in the production of the illumination system according to the invention that the density and size distribution of these scattering centers can be adjusted in a predetermined manner by heat treatment, thereby influencing the scattering effect in a targeted manner.

[0029] The illumination system may comprise a laser light source, which in the operating state emits light, i.e. electromagnetic radiation, in a given spectral range. Lasers advantageously used in a particularly preferred embodiment of the invention for medical treatment, for example for so-called photodynamic therapy (PDT applications), emit at wavelengths that are adapted to a given biochemically modified dye (photosensitizer), usually in the visible range, for example in the green spectral range at 532 nm, or in the red spectral range at 690 nm, for example.

[0030] The light guide is advantageously connected at its proximal end by a connector to the laser light source, where the proximal end refers to the end of the light guide where the light is in-coupled. The light guide comprises a diffuser element at its distal end, where in a particularly preferred embodiment the light guide and the diffuser element are formed in such a way that they can be introduced directly or via a cannula into tumor tissue formed in healthy tissue. The distal end refers to the other end of the light guide, which is usually located away from the proximal end of the light guide and from which the light is in particular emitted.

[0031] Here, laser radiation can reach the diffuser element by optical input coupling at the diffuser element, where the laser radiation is scattered multiple times within the diffuser element and emitted substantially radially and spherically through the surface of the diffuser element.

[0032] In the sense of the present invention, a spherical radiation characteristic in the radial direction of a diffuser element means a spherical radiation, which is uniform in the ideal case, and therefore a completely spherical radiation characteristic in this sense corresponds to radiation that is uniformly formed starting from a point and independent of the angle, similar to a Lambertian emitter, and has the same intensity independent of the angle.

[0033] Here, a certain angular dependence of the radiation is given, or may be desirable for certain embodiments, i.e. the radiation may be stronger or weaker at certain angles, and therefore there is a different radiation intensity depending on the angle. The angular dependence of the radiation can also be used in a targeted manner to compensate for non-uniformities in the radiation, for example due to different concentrations of scattering centers or due to different path lengths through the diffuser body.

[0034] However, it is preferable that the radiation is as uniform as possible in the sphere surrounding the diffuser element. In particular, intensity peaks should be avoided. The light-induced biochemical reactions mentioned at the beginning can ideally lead to necrosis of tumor tissue after treatment with photodynamic therapy.

[0035] Typically, a quartz fiber can be used as the light guide, the connector can typically be configured as a coaxial plug-in connector, a so-called SMA connector or an FC connector, and the fiber is glued into the connector. Connectors with a nickel silver sleeve can also be advantageous in terms of heat resistance, in which case the light guide is introduced or pressed into the nickel silver sleeve by plastic deformation in a form-fitting manner.

[0036] Furthermore, for larger laser powers, connectors can be used in which the fiber ends of the light guides are protected by conical prisms, which can be advantageous in case of misalignment.

[0037] In most embodiments, the light guide may comprise a quartz glass core with a refractive index n1 and a core diameter DC, typically between 50 and 1000 μm, preferably between 200 and 600 μm, and may include a cladding with a refractive index n2, where n1>n2. Usually such fibers further comprise an outer polymer layer, called a buffer, for example made of polyamide or polyimide. The numerical aperture NA thus typically obtained is about 0.22. Quartz glass based light guides are also known, which also have a numerical aperture NA of up to 0.4 using certain dopants. The light input coupling is performed via an input coupling surface formed by a connection zone of the diffuser body.

[0038] To obtain the desired emission characteristics, the diffuser body advantageously has predetermined geometric dimensions and relationships, which are described in more detail below.

[0039] For this purpose, the diffuser body preferably has a substantially spherical, elliptical, drop-shaped and / or cylindrical shape in order to meet the requirements of a substantially radially spherical radiation characteristic. At the same time, such a spherical, elliptical or drop-shaped shape also allows a very compact construction of the diffuser body in a very advantageous manner. Here, the invention also encompasses diffuser bodies having combinations of these basic shapes, i.e. shapes combined from these basic shapes. Further basic shapes include, for example, short cylindrical sections, or, for example, drop-shaped or elliptical shapes, or even dome-shaped shapes. The inventors have found that the desired radiation characteristics can be obtained even if the diffuser body has a cylindrical or elongated shape, if very specific boundary conditions of such a construction are maintained depending on the material and the scattering center. This will be explained in more detail below.

[0040] Here, it is furthermore not excluded that the diffuser body comprises surface regions which deviate from these basic shapes in terms of shape, due to the situation in which the diffuser body is connected to a light guide, which can be most easily realized by a corresponding flattened region of the surface of the diffuser body, which may therefore be formed flat or planar, but it is assumed that the remaining surface of the diffuser body has a shape which deviates therefrom, in particular is not formed planar or planar.

[0041] Furthermore, the radially spherical radiation characteristic is promoted by the extent of the diffuser body, where the maximum extent LD of the diffuser body in a first direction is at most 10 times, preferably at most 5 times, particularly preferably at most 2.5 times, more preferably at most 2 times, particularly preferably at most 1.5 times the extent DD of the diffuser body in a second direction perpendicular to the first direction. Here, the directional extent DD refers to the extent perpendicular to the direction of light input coupling, i.e. perpendicular to the longitudinal direction of the light guide in the region of the input coupling. The directional extent LD means the length of the diffuser body along the longitudinal axis of the diffuser body, i.e. parallel to the direction of light input coupling or parallel to the longitudinal direction of the light guide in the region of the input coupling, if the diffuser body has, for example, a rather oval or elliptical form. It has proven advantageous in principle if the following holds: LD≧DD

[0042] In a particularly preferred embodiment, the extent of the diffuser body in a first direction is equal to the extent of the diffuser body in a second direction perpendicular to the first direction, thereby providing a spherical embodiment.

[0043] The maximum extent LD of the diffuser body in one direction can be in the range of 200 μm to 10 mm or more. In this case, the advantageous length and / or width of the diffuser body depends on several factors. For example, the type of scattering centers and their concentration in the volume of the diffuser body influence the scattering length LS, which indicates the distance from the light input coupling point at which the light intensity drops to the value of 1 / e or 36.8%. Advantageously, this determines the maximum extent LD of the diffuser body, where it turns out to be advantageous for a uniform emission characteristic if the maximum length LD is not more than three times the scattering length, so that: LD≦3*LS Preferably, LD≦2.5*LS, and Particularly preferably, LD≦2*LS

[0044] In a particularly preferred embodiment, LD=LS.

[0045] If the scattering length is 10 mm, the diffuser body may advantageously be 10 mm long as well. Advantageous embodiments are generally between 250 μm and 4 mm, preferably between 300 μm and 3 mm.

[0046] Advantageously, the width of the diffuser body is determined by the core diameter of the light guide. The light guide may comprise a single fiber, for example a monomode or multimode optical fiber comprising a core and a cladding having a core diameter, or a fiber bundle having a fiber bundle diameter. For the quartz fiber used, the outer diameter of the light guide is typically between 200 μm and 800 μm.

[0047] In a preferred embodiment, the light guide may comprise a single fiber having a core with a core diameter and a cladding, the diameter of the diffuser body in the region of the input coupling surface being greater than or at least equal to the light guide core diameter in the region of the input coupling surface, whereby also preferably the ratio of the light guide core diameter to the diameter or width of the diffuser body is ≦1.0-0.7, particularly preferably ≦1.0-0.8.

[0048] In a further preferred embodiment, the light guide can comprise a fiber bundle with a fiber bundle diameter, the diameter of the diffuser body in the region of the input coupling surface being greater than or equal to the fiber bundle diameter of the light guide in the region of the input coupling surface, whereby also preferably the ratio of the fiber bundle diameter of the light guide to the diameter or width of the diffuser body is ≦1.0-0.7, particularly preferably ≦1.0-0.8.

[0049] In a further embodiment, the light guide may be formed as a rigid fiber rod. Here, it can be provided that the diffuser body is glued or spliced ​​to the distal end of a rigid glass fiber rod. For this purpose, it can be provided that the glass fiber rod is conically tapered at the distal end, such that the diameter of the distal end face is approximately equal to the diameter of the diffuser body. Furthermore, it can be provided that the rigid fiber rod has at least one bend. In this way, it is particularly easy to use the illumination system according to the invention with a rigid fiber rod and a diffuser element in the dental field, for example for treating mucositis. Here, it is advantageous to be able to provide a system that is compatible with so-called hardening rods used in the dental field. Such hardening rods are known, for example, from DE 10 2013 208 838 A1, and usually consist of a fiber rod that may be finished in a curved tapered shape, and such hardening rods can be used, for example, to harden dental fillings with blue light.

[0050] In most applications of the lighting according to the invention, it is advantageous if the dimensions of the diffuser body are selected in such a way that emission with a small percentage deviation from the average radiant intensity is possible in the operating state of the lighting system. Here, it is particularly advantageous for most envisaged applications if the deviation of the radiant intensity distribution from the moving average value is no more than ±30%, preferably no more than ±20%, in order to obtain an optimal therapeutic success. In most applications, it is even more suitable for the deviation to be smaller, for example no more than 15%, or even no more than 10%. Applications in which a certain deviation of the radiant characteristics is desirable are excluded here.

[0051] To determine the emissive properties, for example, the intensity, brightness, luminance or lightness of multiple points along a line on the surface of the diffuser body can be measured, and the average emissive intensity can then be based on the average of all values ​​measured along the line.

[0052] The statement that in the operating state the deviation of the radiant intensity distribution of the lighting system from an average value, in particular a moving average value, is not more than ±30%, preferably not more than ±20%, is understood to mean that this deviation is based on a moving average, the averaging being carried out over a number of adjacent points on a straight line.

[0053] The transition area between the light guide and the diffuser body is provided with preferred devices and / or measures to homogenize the radiation in the lateral direction, i.e. perpendicular to the longitudinal direction of the light guide, for example including a layer at the distal end of the light guide to prevent forward directed radiation from the distal end or to reflect such radiation back and provide it again to the scattering process of the diffuser body, while avoiding scattering light effects and / or light reflections in the diffuser body.

[0054] This makes it possible to provide diffuser elements for medical treatments, as mentioned at the outset, which emit uniformly in the operating state, reproducibly and in a cost-optimized manner.

[0055] Uniformity of the radiant intensity can be aided if the diameter of the diffuser body in which the scattering elements are embedded is equal to or greater than the lightguide core diameter or fiber bundle diameter, in which case the diameter of the diffuser body corresponds to the extent of the diffuser body in a direction perpendicular to the longitudinal direction of the lightguide, and thus corresponds to the value DD mentioned above.

[0056] It has proven to be particularly advantageous for the ratio of the light guide core diameter or the fiber bundle diameter to the diameter of the diffuser body to be ≦1.0-0.3, particularly preferably ≦1.0-0.5.

[0057] Now, by reducing the core diameter or fiber bundle diameter just slightly below this diameter, the intensity peak at the input coupling point, i.e., the transition region between the light guide and the diffuser body, can be reduced.

[0058] In contrast, making the core diameter or fiber bundle diameter significantly smaller than the diffuser body diameter, i.e., a ratio <0.8, may result in reduced intensity at the input coupling point, but this may be advantageous for certain requirements as well.

[0059] Furthermore, it has been found that a ratio between 1 and 0.9 provides a particularly robust mechanical coupling or connection between the light guide and the diffuser body, for example by splicing.

[0060] On the other hand, exemplary embodiments are also conceivable in which a diffuser body finished as an approximately spherical sphere with a diameter of, for example, 1 mm is connected, in particular by splicing, to a fiber with a core diameter of 400 μm, where the ratio may be significantly smaller than 1, in this example the ratio is 0.4.

[0061] In a preferred embodiment, the diffuser element has a connection zone between the diffuser body and the distal end of the light guide, which is manufactured by a form-fit and / or material connection by gluing, splicing or crimping, connecting the diffuser body with the core diameter of the light guide or the fiber bundle diameter. In this context, the term splicing means the fusion of at least one of the two objects to be connected, preferably the light guide, i.e. a solid material connection between the diffuser body and the light guide by applying heat to soften it and then bring it into contact, so that a solid connection can be established upon cooling.

[0062] For this purpose, refractive index-matched highly transparent adhesives can be used. In the case of splicing, the light guide and the diffuser body are partially melted and fused by corona discharge and / or a laser, usually a CO2 laser. Depending on the materials used for the diffuser body and the light guide, it may be necessary to use an intermediate medium to match their thermal expansion coefficients. In the case of e.g. glass / quartz glass fusion, this intermediate medium can be a solder or transition glass, or an optical glue or cement.

[0063] It may be advantageous if an intermediate medium is additionally provided in the connection zone between the diffuser body and the distal end of the light guide in order to match the possibly different thermal expansion coefficients. For example, this may be a transition glass or a solder glass. On the other hand, it may be a transparent, permanently elastic adhesive. Furthermore, optical elements may be arranged in the connection zone or may be finished as optical elements in order to modify the beam guidance and / or light steering, for example by matching the shape or refractive power.

[0064] Furthermore, it is advantageous to provide a jacket for protecting the diffuser body, which in a preferred embodiment advantageously surrounds the diffuser body at least partially or regionally or even completely, whereby it may be advantageous for at least the connection zone between the diffuser body and the light guide to be additionally surrounded as well, thereby increasing the mechanical durability of the light guide / diffuser body connection. Advantageously, since the light guide does not have a buffer layer in this region, this zone can be protected by such a jacket without the need to carry out a so-called recoating process for mechanical protection.

[0065] In a particularly advantageous embodiment, the diffuser body no longer has an unprotected surface that is not covered with a protective jacket, either in the direction or in the area of ​​the input coupling point or in the opposite direction. This provides additional reliable protection of the surface of the diffuser body and / or the input coupling point from external damage to the surface of the diffuser body, such as cracks or scratches as a result of use, which may be very detrimental for the envisaged application, since this would change the emission characteristics. This allows the lifetime of the lighting system to be extended.

[0066] In a further particularly advantageous embodiment, the jacket surrounds at least the connection zone between the diffuser body and the light guide, thus ensuring a particularly high stability of the connection, since the outer region of the connection is particularly well protected from external influences. The jacket, which protects and surrounds at least the connection zone between the diffuser body and the light guide, offers a further great advantage. Since the light guide does not have a buffer layer here, this region is prone to corrosion, for example due to water vapor in the atmosphere or due to contact with liquids or moisture during use. Thus, the moisture-proof jacket, especially in this region, also reliably protects the light guide in the contact region with the diffuser body against corrosion, which thus likewise increases the service life of the lighting system.

[0067] In this case, the jacket can include a layer that is transparent or semi-transparent for the light emitted laterally from the diffuser element, which consists of liquid silicone, thermoplastic polymer, melt-type adhesive, two-component adhesive or sol-gel glass, shrink tube or additionally attached transparent or semi-transparent mounting elements, which surround the diffuser body and / or the transition between the diffuser body and the light guide. A varnish layer containing additional light-scattering pigments, for example in the form of titanium oxide, aluminum oxide or calcium carbonate, has also proven to be advantageous. This makes it possible to achieve a further homogenization of the emission. This layer can be applied, for example, as a dip layer or by coating the surface.

[0068] It is also conceivable to include a glass with a relatively low melting point, which has a low processing temperature, advantageously below 500°C, preferably below 400°C, particularly preferably below 300°C. When selecting a suitable glass, care should be taken to ensure that the softening or processing temperature of the selected glass is lower than the softening or processing temperature of the diffuser element or diffuser body. This ensures that no undesirable changes can occur, for example with respect to the scattering centers and thus the radiation properties, when the low-melting glass is applied to the diffuser body. It is advantageous that the processing temperature of the applied material is at least 50K, preferably at least 100K, lower than the softening temperature of the diffuser element. What should be taken into account here is that the diffuser element can include various materials, as can, for example, the core and / or cladding of the light guide and the diffuser body. These possibly different softening temperatures are therefore advantageously taken into account.

[0069] In this case, the jacket has a certain minimum and maximum thickness so that, on the one hand, sufficient protection of the diffuser body is provided, and, on the other hand, the entire diffuser element is not too large for the intended application: a jacket made too thick may also lead to undesirable radiation attenuation.

[0070] The typical thickness of the varnish layer is about 10 μm to 100 μm, and multiple layers may be provided. Typical thicknesses of the tube start from about 5 μm and go up to about 500 μm.

[0071] Preferably, the diffuser element comprises or is formed as at least one scattering element and comprises at least one scattering center. In the present invention, the radially spherical radiation characteristic is caused by scattering of light introduced into the diffuser body in a scattering region in which scattering occurs.

[0072] The cause of scattering is scattering centers, which are embedded in the scattering regions. In the sense of the present invention, scattering centers are in principle all particles and / or material aggregates and / or inhomogeneous regions that can scatter light, regardless of their shape, material and / or size. Scattering centers can exert their scattering effect by classical scattering, in particular Rayleigh and / or Mie scattering, as well as by diffraction and / or reflection, as well as by multiple processes of these mechanisms. Their function is only to deflect the incident light, individually or collectively.

[0073] Optically active pigments, such as phosphorescent materials, i.e. materials that can luminesce upon excitation, are also conceivable. These can, for example, contain certain phosphorescent materials that can convert and emit light of a certain wavelength of illumination into light of another wavelength. In addition to these materials characterized by their phosphorescence, for example, fluorescent materials can also be used. Such materials are also known as organic or inorganic phosphors, which can be embedded in matrices made of inert materials, such as, for example, plastics (epoxy and silicone), glass, glass-ceramics or glass-like materials or ceramics, and ceramic converters that form phosphors, so-called optoceramics. With these, it is also possible to achieve an emission in which the spectrum of the incident wavelength overlaps the spectrum of the emitted wavelength.

[0074] The multiple scattering centers may be arranged within the volume in a predefined geometric arrangement, which may be predefined, preferably around the center of the diffuser body.

[0075] Different arrangements and / or concentrations of scattering centers within the volume of the diffuser body are possible.

[0076] Thus, in a preferred embodiment, it is possible to provide that the scattering centers are arranged in a regular structure within the volume of the diffuser body, advantageously with a uniform concentration around the center, which results in a uniform concentration within the volume. The density of the scattering centers can be adjusted by chemical or thermal processes, so that it is possible to set a uniform distribution throughout the volume, but also a non-uniform distribution.

[0077] In a further embodiment, a composite comprising at least one strongly scattering material, for example highly doped white glass, may be provided as scattering element. The scattering can be locally tuned by targeted embedded scattering centers.

[0078] In another embodiment, it can be provided that the core zone around the center of the diffuser body does not have any scattering centers or has a number of scattering centers per unit volume that is significantly reduced compared to the number of scattering centers per unit volume outside the core zone, and thus the scattering centers are mainly located outside this core zone. In this case, the core zone advantageously corresponds to a volume that surrounds the center and has an extent of less than half the maximum extent of the diffuser body in one direction. This makes it possible to achieve that the input coupling light, which is generally input coupled with a low NA (<0.3, typically about 0.2), is not immediately scattered by the scattering centers, but is emitted spherically and uniformly with the same intensity.

[0079] Thus, in this embodiment, the density of scattering centers in the region near the surface of the diffuser body is different from the density of scattering centers in the region near the center of the diffuser body, in which case preferably the density of scattering centers in the region near the surface is greater than the density of scattering centers in the region near the center, and particularly preferably there is a gradient of scattering center density, where the term scattering center density means density, i.e. the number of scattering centers per unit volume.

[0080] Scattering centres include in particular pores, particles, crystallites, polycrystallites, porous and / or coloured and / or optically active pigments, for example in the form of phosphors and / or coloured regions, for example coloured particles, coloured crystallites or coloured pigments, or colourants of glass, or inhomogeneities in the form of refractive index variations, or any combination of such scattering centres, and inhomogeneities of inorganic materials include phase separations, segregations and / or particle inclusions, nuclei and / or crystallites.

[0081] In this case, combinations of the scattering centers mentioned above by way of example can also be advantageously present in the inorganic material. In the case of glass or glass ceramic matrix solutions, glass or glass ceramic inclusions which can form scattering elements include, for example, phase separations, segregations and / or particle inclusions, nuclei and / or crystallites.

[0082] When glass or glass ceramics are used as the inorganic material of the diffuser body, the scattering centers can preferably be formed by embedding scattering particles in the glass or glass ceramic, but the scattering centers can also be formed by inhomogeneous regions of the glass or glass ceramic in which they are embedded.

[0083] Such scattering centers based on scattering particles in glass or glass ceramics or inhomogeneous regions of glass or glass ceramics, and the underlying manufacturing method, are described, for example, in the applicant's WO 2009 / 100834, the entire contents of which form part of the subject matter of the present invention.

[0084] If scattering particles are used as scattering centers, then preferably those having a melting point higher than the melting point of the glass or glass ceramic they are embedded in are used, which makes their selection easier since the manufacturing process at least does not change their scattering properties and therefore they can be purchased as raw material.

[0085] Preferably, the scattering particles have a diameter of 10 nm to 5000 nm, particularly preferably 100 nm to 1200 nm. In the case of non-round scattering particles, the diameter in the sense of the present invention is understood to mean its maximum extent. This also applies to the size data elsewhere, and in the case of the original object having no diameter, the diameter data should likewise be understood to mean the maximum extent in one direction. The scattering particles of the above dimensions are suitable, for example, for combination with white glass as the material of the diffuser body.

[0086] These dimensions may also apply to other forms of scattering centers, such as pores, crystallites or inclusions, where inclusions resulting from phase separation or segregation may have rather smaller diameters, for example in the range of 10 nm to 1000 nm, or 100 nm to 800 nm. Thus, for example, advantageous dimensions of particles or pores in borosilicate glass are envisaged to be about 200 nm to 700 nm, or 200 nm to 500 nm.

[0087] The scattering particles may be selected from a number of materials. Preferably, they consist essentially of SiO2 and / or BaO and / or MgO and / or BN and / or AlN and / or SN and / or ZrO2 and / or Y2O3 and / or Al2O3 and / or TiO2 and / or Ru and / or Os and / or Rh and / or Ir and / or Ag and / or Au and / or Pd and / or Pt and / or diamond-like carbon and / or glass-ceramic particles. As well as only the metallic components of the aforementioned oxides and nitrides, mixtures of scattering particles consisting of different materials, compounds and / or aggregates thereof, or scattering particles melted and / or sintered together, are also conceivable and are encompassed by the present invention.

[0088] In addition to the scattering properties of the scattering particles as an intrinsic parameter, the efficiency of output coupling from the scattering region also depends on the concentration of the scattering particles in the scattering region itself. By selecting the concentration of the scattering centers in the scattering region, it is possible to scale the emission. Thus, in one embodiment of the present invention, it is provided that the scattering centers are formed by scattering particles, and that the concentration of the scattering particles in the scattering region is between 10 ppm and 1000 ppm, preferably between 20 ppm and 100 ppm. Here, the concentration data in ppm refers to the proportion of the scattering particles relative to the mass fraction of the components of the respective inorganic material in which the scattering particles are embedded. It has been found that these concentrations are useful even if different types of scattering centers, for example pores, inhomogeneities in the material or crystallites, are present in the case of glass-ceramics.

[0089] In the case where inhomogeneous regions of, for example, a glass or glass ceramic function as scattering centers, an alternative embodiment of the invention arises in that the inhomogeneous regions are preferably formed by phase separation and / or segregation of the components of the glass or glass ceramic in which they are embedded.

[0090] According to the invention, as mentioned above, the diffuser body itself comprises an inorganic material, in particular glass, glass ceramics, quartz glass or glass-like material, or a composite material composed of the aforementioned materials. However, glasses, multi-component glasses or glass ceramics, or composite materials composed of these materials, are particularly preferably used, since they facilitate easier and better adjustment of the radiation properties.

[0091] Glass or glass ceramics are particularly suitable as materials for the diffuser body, since they are much more robust and, in particular, more thermally stable compared to, for example, plastics, and therefore higher laser powers can be applied.

[0092] For the envisaged applications, materials that have a neutral behavior with respect to electromagnetic radiation in the wavelength range selected for the envisaged application and thus advantageously emitted by the light source can be considered as particularly suitable for the diffuser body. The wavelength range of electromagnetic radiation relevant to the present invention is from about 0.4 μm to about 2.2 μm. For phototherapy applications, typical ranges are the visible spectrum, in particular the red spectral range of 600 nm to 700 nm, in particular 690 nm, or the NIR range of 700 nm to 1000 nm. Here, EVLT applications rather target wavelengths in the range of 800 nm to 2.2 μm, typically 980 nm to 1100 nm, about 1500 nm, and the range of 1.9 μm to 2.2 μm.

[0093] According to the invention, in a first embodiment, it is provided that a glass with or without inherent coloring is selected for the diffuser body, in which the desired wavelengths of electromagnetic radiation are not absorbed by the glass, which may be a white glass containing a white pigment to produce a whitish impression.

[0094] In a particularly preferred embodiment, the diffuser body comprises a silicate white glass, which has an extreme scattering effect. Advantageously, it is an As-Pb-containing silicate glass. Such glasses are silicate glasses containing lead (Pb) and arsenic (As). If there are inhomogeneous regions as scattering elements, these may have an increased content of lead and / or arsenic compared to the surrounding glass. Alternatively, scattering elements, such as scattering particles, may be embedded, which of course form scattering centers.

[0095] A particularly suitable glass for the diffuser body is Na-Al-K-As-Pb silicate glass. This can contain at least 25% by weight of lead oxide in the glass, preferably at least 30% by weight of lead oxide. In that case, the inhomogeneous regions, which are scattering elements, for example droplet-like segregation zones with a high lead content, form lead arsenate with, for example, 38% by weight of lead, and furthermore, these segregation zones can have a diameter of 100 nm to 600 nm. Na-Al-K-As-Pb silicate glass can contain 3% by weight or more of arsenic oxide. Possible compositions of Na-Al-K-As-Pb silicate glasses suitable according to the invention are shown in Table 1.

[0096] [Table 1]

[0097] In a particularly preferred embodiment, a Na-Al-K-As-Pb silicate glass with 30% by weight of lead oxide and 3% by weight of arsenic oxide is selected as the colored glass with a white impression. No scattering particles are introduced, and the initially colorless and transparent colored glass is segregated during production, resulting in uniformly distributed segregation zones with a diameter of 50 nm to 500 nm. These segregation zones are lead arsenate and have a refractive index much higher than that of the base glass, resulting in a scattering effect. The colored glass, now white and opaque, can then be further processed to give it the shape desired for the diffuser body, i.e., for example, spherical.

[0098] Of course, other glasses, including lead-free glasses or glasses containing no or low amounts of heavy metals, are possible and suitable for the present invention.

[0099] Examples of such glasses for the diffuser body comprised of a range of lead-free tin silicate glasses or alkali tin silicate glasses include the following components (given in weight % on an oxide basis): [Table 2] For example, lead-free and arsenic-free Na-Al-K-Ca-Zn silicate glasses can be used, which may be advantageous from an environmental point of view. Again, for example, spherical pores can be formed in the volume, which in this case represent calcium-rich deposits. Scattering centers are formed by these inhomogeneities in the glass. The achievable size of the pores is up to 500 nm. The calcium-rich deposits in these segregation zones consist of CaF2.

[0100] Further suitable glasses are N-BK7 type glasses, optical borocrown glasses according to the applicant, or borosilicate glasses.

[0101] In this connection, mention should be made of further materials which are highly suitable for the present invention, for example for inducing Mie scattering, which means scattering which occurs when defects, e.g. inclusions, are comparable in size to the actual wavelength, i.e. more than 10% of the wavelength.

[0102] The production and various configurations of such materials are described in the applicant's WO 2014 / 165048 or in the German translation of WO 112014001293, the entire contents of which relating to this likewise form part of the subject matter of the present invention.

[0103] In accordance with the present invention, the diffuser body may be made of a porous or phase separated glass that is shaped to optimize scattering in a desired radiation direction while simultaneously providing a desired solid angle of scattered light in the desired radiation direction.

[0104] Thus, according to further embodiments of the present invention, there is provided a scattering diffuser body formed from a glass system undergoing phase separation, such as, for example, conventional borosilicate glass systems; the KO-SiO, KO-LiO-SiO, KO-NaO-SiO and KO-BaO-SiO systems (Kawamoto and Tomozawa, 1981, J. Amer. Ceram. Soc., vol. 64 (5), 289-292); the MgO-AlO-SiO system (Zdaniewski, 1978, J. Amer. Ceram. Soc., vol. 61 (5-6), pages 199-204), and the CdF-LiF-AlF-PbF system (Randall et al., 1988, J. Amer. Ceram. Soc., vol. 71 (12), pages 1134-1141).

[0105] These can be subjected to a phase separation by a controlled heat treatment, in which case the glass composition separates into two phases, and can optionally be subjected to further measures to generate open porosity within the glass by a leaching step, whereby open porosity can be obtained in the order of 200-700 nm, for example 200-500 nm, preferably 300-500 nm, particularly preferably 300-450 nm, and about 10 8 ~10 12 mm -3 , preferably 10 9 ~10 11 mm -3 , particularly preferably 10 20 ~10 11 mm -3 Thus, a glass having pores with a number density of

[0106] According to a further aspect of the invention, there is provided a diffuser body having scattering elements, which is manufactured by melting a borosilicate glass, preferably an alkali borosilicate glass, which is slowly cooled for stress relief and then subjected to a phase separation by a well-controlled heat treatment, in which the composition separates into a silicate-rich phase and a boron-rich phase, and which can optionally be subjected to further measures to generate open porosity within the glass by acid leaching and pore-cleaning caustic leaching steps, whereby open porosity is obtained within the glass, in the order of 200-700 nm, for example 200-500 nm, preferably 300-500 nm, particularly preferably 300-450 nm, and having a size of about 100 nm. 8 ~10 12 mm -3 , preferably 10 9 ~10 11 mm -3 , particularly preferably 10 10 ~10 11 mm -3 A diffuser body is provided, which results in glass having pores with a number density of

[0107] According to a further aspect of the invention, there is provided a diffuser element comprising at least one optical fiber and at least one Mie scattering diffuser body for diffusing light emitted by the at least one optical fiber, the at least one Mie scattering diffuser body having a diameter of 10 mm or less. 8 ~10 12 mm -3 or a phase separated or porous glass (e.g., a borosilicate glass, preferably an alkali borosilicate glass) having pores with a size of 200 to 700 nm, e.g., 200 to 500 nm, at a number density of 0.1 to 0.5 μm.

[0108] According to a further aspect of the invention, there is provided an illumination system including an optical fiber or fiber optic bundle and an optical scattering element bonded to a distal end of the optical fiber or fiber optic bundle for diffusing light emitted from the distal end of the optical fiber or fiber optic bundle, the optical scattering element comprising:8 ~10 12 mm -3 or a phase separated or porous glass (e.g., a borosilicate glass, preferably an alkali borosilicate glass) having pores with a size of 200-700 nm, e.g., 200-500 nm, at a number density of 0.1 to 0.5 μm.

[0109] Reference to particle sizes, e.g., 200-700 nm, and pore sizes, e.g., 200-700 nm, means that the relevant pores or particles have an actual diameter of 200-700 nm. Thus, for example, in a diffuser body according to the present invention, the amount, i.e., number density, of pores or particles having an actual diameter, e.g., of 200-700 nm, is 10 8 ~10 12 mm -3 (Preferably 10 9 ~10 11 mm -3 , particularly preferably 10 10 ~10 11 mm -3 ).

[0110] The diffuser body may contain particles or pores with actual diameters outside the range of 200-700 nm, but the number of particles or pores with actual diameters between 200 and 700 nm is less than 10. 8 ~10 12 mm -3 (Preferably 10 9 ~10 11 mm -3 , particularly preferably 10 10 ~10 11 mm -3 ).

[0111] According to a further aspect of the invention, there is provided a method for manufacturing a diffuser element having a Mie scattering diffuser body, comprising subjecting a glass (e.g., a borosilicate glass, preferably an alkali borosilicate glass) that has been annealed for stress relief to phase separation by controlled heat treatment, and optionally subjecting the phase separated glass to an acid leaching step to generate pores and a caustic leaching to clean the resulting pores, and bonding the resulting Mie scattering optical element to the end of an optical fiber or the end of an optical fiber bundle.

[0112] According to a further aspect, there is provided a method for diffusing or scattering light, the method comprising the steps of: 8 ~10 12 mm -3 in a number density of 200 to 700 nm, e.g., 200 to 500 nm, or a phase separated or porous glass (e.g., borosilicate glass, or alkali borosilicate glass) having pores with a size of 200 to 700 nm, e.g., 200 to 500 nm.

[0113] For example, the optical scattering elements can be manufactured by melting a borosilicate glass, preferably an alkali borosilicate glass, which is subjected to phase separation by well-controlled heat treatment after slow cooling for stress relief, and optionally further measures to generate open porosity within the glass by acid leaching and pore-cleaning caustic leaching steps, thereby producing open porosity of the order of 200-700 nm, for example 200-500 nm, preferably 300-500 nm, in particular 300-450 nm, and of the order of about 10 8 ~10 12 mm -3 , preferably 10 9 ~10 11 mm -3 , particularly preferably 10 10 ~10 11 mm -3 Thus, a glass having pores with a number density of

[0114] According to the present invention, the heat treatment of a borosilicate mother glass, preferably an alkali borosilicate glass, advantageously induces a glass-in-glass phase separation with any of the compositions listed below. The phases are defined as a silicate-rich phase and a boron-rich phase. After undergoing heat treatment, the mother glass can be chemically leached. When the mother glass is chemically leached, the host or bulk phase is considered to be the silicate-rich phase and the pores resulting from the removal of the boron-rich phase are considered to be scattering properties.

[0115] Such nano-range particles are in the order of 200 to 700 nm, for example 200 to 500 nm, and have a size of about 10 8 ~10 12 mm -3 In order to obtain a glass with a combination of features with a number density of 1000 nm, it is desirable to subject the glass to a well-controlled heat treatment profile. Commercially, porous glass, for example from SCHOTT AG (Mainz), is known under the trade name CoralPor™ for applications, for example, in chromatography media, reference electrode junctions, as a host material for sensors, and as an additive (filler) in coatings (see James et al., US Patent Application Publication No. 2013 / 0017387). During production, CoralPor™ porous glass is subjected to a carefully controlled heat treatment to induce glass-in-glass phase separation. Ultimately, this heat treatment determines the final size of the scattering features present in the material. This allows the desired criteria, i.e., 100 nm to be achieved. 8 ~10 12 mm -3 This allows the manufacturing process to be engineered to produce CoralPor™ porous glass with particle densities of 200-700, eg, 200-500 nm features.

[0116] According to the invention, the scattering optical elements can be produced, for example, by subjecting a borosilicate glass, preferably an alkali borosilicate glass, to phase separation by heat treatment, for example with a controlled temperature / time profile in the temperature range of 500-800°C, for example 600-800°C, preferably 650-750°C, more preferably 700-725°C, for example for a period of 1-150 hours, for example 24-48 hours or 48-80 hours. For example, for a given composition, a heat treatment used to obtain nano-range features of about 200 nm can include a duration of 20-26 hours at 700°C. Here, the cooling stage is also important, which likewise needs to be controlled accordingly with respect to its temperature / time profile in order to obtain an optimal or desired scattering effect.

[0117] The conditions can be set based on the melting parameters (i.e., temperature and quenching method) and composition used. Generally, the method used depends on the desired phase growth. For example, generally, increasing the temperature for a longer period in the phase separation region will increase the feature size, but the feature size also depends on the specific composition.

[0118] This heat treatment method can be considered complete for some applications. In other words, for some applications, it is possible to achieve a heat treatment of about 10 8 ~10 12 mm -3 No additional method steps are required to achieve the desired result of features between 200 nm and 700 nm, for example between 200 and 500 nm, at a population density of 100 nm to 150 nm.

[0119] The base glass may be, for example, a borosilicate glass having an appropriate silicon dioxide and borate content for phase separation to occur, and sufficient borate content to obtain the desired number density of nano-range pores. Preferably, the borosilicate glass includes at least some alkali metal oxide. For example, a borosilicate glass composition according to one embodiment of the present invention includes (on a weight percent basis): B2O3 15.00-40.00 SiO245.00~80.00 RO 0.0~20.0 R'O 0.0~20.00 RO20.0~10.00 Al2O30.0~10.00 where R2O is the sum of Li2O, Na2O, K2O, Rb2O, and Cs2O (and is preferably greater than 0); R'O is the sum of BaO, CaO, MgO, SrO, PbO, and ZnO; R″O2 is the sum of TiO2, ZrO2, and HfO2.

[0120] Further borosilicate glass compositions suitable for the present invention are set forth below (on a weight percent basis): 65%~85% SiO2 6%~15% B2O3 3%~9% Alkali metal oxides (sodium oxide Na2O, potassium oxide K2O) 1%~8% Al2O3 0%~5% alkaline earth metal oxides (CaO, MgO, ...)

[0121] With respect to ranges recited herein, any range includes at least the two endpoints of the range, and all values ​​between those two endpoints, and thus, for example, a range of 1 to 10 should be understood as being meant to explicitly disclose values ​​such as 1.0, 1.5, 2.0, 2.8, 3.0, 3.1, 4.0, 4.2, 5.0, 5.3, 6.0, 7.0, 7.7, 8.0, 9.0, 9.9, or 10.0.

[0122] In borosilicate glasses, SiO2 functions as the main network former. Thus, according to a further aspect of the invention, the borosilicate glass composition comprises 45.00-80.00 wt.% SiO2, for example 45.00-75.00 wt.% SiO2, or 45.00-70.00 wt.% SiO2, or 45.00-65.00 wt.% SiO2, or 45.00-60.00 wt.% SiO2, or 50.00-60.00 wt.% SiO2.

[0123] In borosilicate glasses, B2O3 functions as a network former and as the primary former of nano-range features of the resulting phase separated / porous glass. Thus, according to a further aspect of the invention, the borosilicate glass composition comprises 15.00-40.00 wt.% B2O3, e.g., 20.00-35.00 wt.% B2O3, or 20.00-30.00 wt.% B2O3.

[0124] According to a further aspect, the borosilicate glass composition comprises 0.00-20.00 wt.% R2O (preferably >0.00-20.00 wt.% R2O), where R2O is the sum of Li2O, Na2O, K2O, Rb2O, and Cs2O, e.g., 1.00-15.00 wt.% R2O, or 1.00-10.00 wt.% R2O, or 2.00-8.00 wt.% R2O.

[0125] According to a further embodiment, the borosilicate glass composition comprises 0.00-20.00 wt.% R'O (the sum of BaO, CaO, MgO, SrO, PbO, and ZnO), such as 1.00-15.00 wt.% R'O, or 1.00-10.00 wt.% R'O, or 2.00-8.00 wt.% R'O. The R'O metal oxides can be used to adjust the refractive index of each phase.

[0126] According to a further embodiment, the borosilicate glass composition comprises 0.00-10.00 wt.% R″O2 (total of TiO2, ZrO2, and HfO2), such as 0.00-8.00 wt.% R″O2, or 1.00-8.00 wt.% R″O2, or 0.00-5.00 wt.% R″O2, or 1.00-5.00 wt.% R″O2. These metal oxides can be used to improve chemical resistance as well as adjust the refractive index of each phase.

[0127] In borosilicate glass compositions, Al2O3 usually functions as an auxiliary network former and can also be used to enhance chemical resistance. Thus, according to a further aspect, the borosilicate glass composition according to the invention comprises 0.00-10.00 wt.% Al2O3, for example 0.00-8.00 wt.% Al2O3, or 1.00-8.00 wt.% Al2O3, or 0.00-5.00 wt.% Al2O3, or 1.00-5.00 wt.% Al2O3, or 2.50-5.00 wt.% Al2O3.

[0128] According to a further embodiment, the glass may be a glass according to the glass composition described in James et al. (US 2013 / 0017387). The glass composition comprises (by weight) 40-80% SiO2, 5-35% B2O3, and 1-10% Na2O, preferably 45-65% SiO2, 20-30% B2O3, and 2-8% Na2O, particularly preferably 50-55% SiO2, 25-27% B2O3, and 5-7% Na2O. As disclosed in US 2013 / 0017387, the glass may comprise further components, such as ZrO2, TiO2, Al2O3, CaO and / or ZnO, and optionally further components, such as oxides of Mg, Fe, Mn, Ce, Sn, etc.

[0129] Further examples of base glasses A to T suitable for use according to the invention are given in Tables 2 to 5 below.

[0130] Overall, during segregation, the presence of a phase with a higher refractive index in addition to a phase with a lower refractive index is important to obtain a scattering effect.

[0131] [Table 3]

[0132] [Table 4]

[0133] [Table 5]

[0134] [Table 6]

[0135] A diffuser body which is particularly preferred in terms of its manufacturing method results if the diffuser body is made from borosilicate glass, tin silicate glass or alkali tin silicate glass and the scattering elements are formed from white glass.

[0136] According to yet another embodiment of the present invention, there is provided a diffuser body comprising or made of a glass-ceramic material, the use of a glass-ceramic material for the diffuser body having the advantage that the entire diffuser body is at least partially or regionally identifiable in an X-ray image, making it possible to identify the location of the diffuser within the patient's body.

[0137] Furthermore, glass ceramic materials are particularly important for the present invention because they have a very high thermal shock stability and a high spectral transmittance up to a wavelength of about 2.5 μm. Here, glass ceramic materials can be used not only for the diffuser body, but also as scattering elements, for example, keatite glass ceramics, which can be produced from high quartz mixed crystal glass ceramics by a suitable heating process. Furthermore, cordierite glass ceramics or magnesium aluminum silicate glass ceramics are also suitable as the diffuser body and / or scattering elements.

[0138] Glass-ceramic materials that are particularly suitable for the diffuser body and / or scattering center are glass-ceramics based on lithium aluminosilicate glass-ceramics (LAS glass-ceramics). In the case of glass-ceramics based on these, it is possible to select between the clear, transparent, high-quartz mixed crystal phase of the material and the opaque keatite phase as required by the heating process, and therefore they appear to be particularly suitable. In other words, glass-ceramics, preferably lithium aluminosilicate glass-ceramics, are produced in which the size of the crystallites and their distribution in the volume are targeted by the targeted application of temperature / time through crystal formation and crystal growth, and the crystallites function as scattering centers of the glass-ceramics. For example, such glass-ceramic materials are available from SCHOTT AG (Mainz) under the trade name CERAN CLEARTRANS® for cooktops or under the trade name ROBAX® for fireplace viewing windows. Such glass-ceramics and manufacturing methods are also mentioned, for example, in the applicant's EP-A-1 266 543, the entire contents of which likewise form part of the subject matter of the present invention.

[0139] In principle, it is also possible to use radiopaque glasses or correspondingly transparent glass-ceramics for the diffuser body or for the embedded scattering elements and / or the jacket.

[0140] Considering the wavelength range from 0.4 μm to about 2.2 μm, for example, when the illumination system is used for endovenous laser therapy (EVLT), one can also use specific IR-transmitting glasses, such as those known under the trade names N-PK52a, phosphate crown glass, or IRG7, a lead silicate glass, all of which are available from SCHOTT AG, Mainz.

[0141] If the diffuser body is subjected to a subsequent heat treatment, in particular a gradient heat treatment, it is also possible to influence the scattering centers in the diffuser body a posteriori with respect to their scattering effect. Thus, for example, the segregation process in the tiny rods of white glass used as scattering centers can be altered by such a gradient heat treatment. If the scattering centers are based on glass ceramics, the crystal formation and crystal growth, or the size of the crystallites and their distribution within the volume of the diffuser body, can be influenced.

[0142] The resulting diffuser body can then be connected to the light guide by splicing or gluing with an index-matched adhesive.

[0143] In order to reduce undesirable scattering, stray light effects and / or light reflections, particularly in the transition region from the light guide to the diffuser body, in a further variant of a preferred embodiment it can be provided that scattering centers immediately adjacent to the input coupling surface of the diffuser body have a reduced scattering effect compared to the scattering effect in the remaining regions of the diffuser body.

[0144] For example, this can be achieved by applying additional temperature, for example during the splicing process of the diffuser body and the light guide, so that the segregation (e.g. phase separation, devitrification) present in the scattering element made of white glass can be at least partially changed locally, for example reduced or even reversed again, so that the scattering effect is reduced in this region.

[0145] In any of the above materials and methods for manufacturing the diffuser body, a wavelength-dependent scattering effect can be obtained by a certain temperature / time regime, which essentially affects the size of the scattering centers. Thus, depending on the applied wavelength or wavelength range, an optimal scattering effect can be obtained, and thus requirements regarding, for example, radiation uniformity can be met. This allows the radiation characteristics to be tailored.

[0146] Furthermore, further downstream processes are conceivable that can correct or adapt the lateral radiation intensity profile of the diffuser body. These include in particular processes that, on the one hand, can at least locally modify the properties, such as its refractive index and / or composition, within the volume and / or at the surface of the material, as for example colloidal precipitation and / or nucleation and / or crystallization, and / or, on the other hand, allow modifications that remove or apply material in almost any geometric shape and configuration.

[0147] These include, for example, laser machining processes, which can introduce a refractive index or create structures in a volume, for example in a cavity, and / or at a surface, for example by means of a short pulse laser or a CO2 laser.

[0148] Furthermore, printing processes can be applied to apply or produce structures, such as, for example, grid profile structures, on the surface of the diffuser element and / or the diffuser body and / or jacket, for example with printable organic or ceramic colorants containing corresponding pigments or with colorants based on glass fluxes, if necessary with corresponding thermal post-treatment. Also feasible are, for example, photolithographic methods and process steps, in particular as used for the structuring of volumes or surfaces of, for example, photosensitive or photostructurable glasses and glass ceramics.

[0149] Also possible is optionally selective wet or dry chemical etching of the diffuser body and / or diffuser element at its surface, where again photolithographic process steps can be applied. Processes with mechanical and / or abrasive effects can also be used to structure, in particular roughen, the surface of the diffuser element and / or diffuser body and / or jacket, for example grinding, lapping or sandblasting.

[0150] The proposed exemplary approaches or methods can also be applied in combination. Thus, the diffuser element and / or the diffuser body and / or jacket so manufacturable have at least partial or regional structures within their volume and / or on their surface.

[0151] In a further advantageous embodiment variant, it can be provided that the diffuser body has, at least partially and / or regionally, a coating with scattering particles and / or that the diffuser body has, at least partially and / or regionally, a further additional sleeve made of colored glass or colored plastic. An example of such a coating, which further supports the Lambertian radiation characteristics and in particular reduces radiation directed forward in the light input coupling direction, is a coating with boron nitride (BN). An additional coating of this type can consist, for example, of titanium oxide, calcium carbonate or zirconium oxide.

[0152] This additional sleeve may be finished, for example, from a white glass containing scattering elements in its glass matrix. In the transition region, in the region of the connection point or in the region of the intermediate medium between the diffuser body and the light guide, for example a colored glass tube may be provided as an additional sleeve, the color and its intensity being selected in particular such that the wavelength of light used is suppressed or even blocked.

[0153] This makes it possible to suppress unwanted reflections and therefore unwanted radiation. A suitable sleeve made of plastic can be, for example, a colored silicone or PTFE or FEP tube. Advantageously, a suitable dip coating made of silicone or a suitable plastic or varnish can also be used.

[0154] In any of the above exemplary embodiments, care must be taken that the diffuser element and / or the diffuser body and / or the jacket have low absorption at the respective application wavelength, taking into account that the heating of the components applied to the body, especially the elements of the components listed below, is as little as possible, where in particular a rise in temperature above 42° C. must be avoided from a medical-technical point of view. This is even more important, for example, when the diffuser is operated with a relatively high laser power for a certain type of treatment, unless this is a treatment that is specifically aimed at heating the tissue (for example LITT).

[0155] The production of a diffuser body according to the invention with an application-adapted illumination profile, in particular with a desired radial spherical radiation intensity uniformity in operating conditions, places high demands on the various process steps, and therefore the method for producing the diffuser body according to the invention is likewise an important further aspect of the invention.

[0156] Thus, in a possible method for manufacturing a diffuser body, in particular for use on or together with the lighting system described above, comprising at least one diffuser element having at least one diffuser body and at least one scattering element, advantageously with at least one scattering center arranged within the volume of the diffuser body, a method is indicated which advantageously comprises the method steps described below.

[0157] Exemplarily, a method for producing a diffuser body made of white glass with scattering particles as scattering centers is shown. A method is provided for forming the white glass into a rod shape by a suitable drawing process. The diameter of such a rod can be in the range of 0.2 mm to 2 mm or even larger, and is determined by the desired size of the diffuser body. Drawing can be performed directly from a glass melt with the corresponding component composition as indicated above.

[0158] The scattering centers, for example in white glass rods, can be formed, for example, by scattering particles or by inhomogeneous regions. The diameter of the scattering centers in such rods may preferably be 10 nm to 2000 nm, particularly preferably 100 nm to 1200 nm.

[0159] If scattering particles embedded in the material volume of the rod are used as scattering centers, these can be supplied to the melt in a particularly advantageous manner, which may comprise SiO2 and / or SiN and / or BaO and / or MgO and / or ZnO and / or Al2O3 and / or AlN and / or TiO2 and / or ZrO2 and / or Y2O3 and / or metals only of the aforementioned oxides and / or BN and / or B2O3 and / or Ru and / or Os and / or Rh and / or Ir and / or Ag and / or Au and / or Pd and / or Pt and / or diamond-like carbon and / or glass-ceramic particles.

[0160] The concentration of the scattering particles in the melt likewise depends on the desired concentration in the diffuser body and may be preferably between 10 ppm and 1000 ppm, particularly preferably between 20 ppm and 100 ppm. After the addition of the scattering particles, the glass melt is advantageously homogenized, for example by means of a suitable stirrer, to obtain the desired homogeneous distribution, which can be checked on the basis of samples taken from the melt.

[0161] In contrast, when inhomogeneous regions of glass are used as scattering centers, the concentration of inhomogeneous regions in the glass rod is preferably 1% to 80%, particularly preferably 10% to 50% (by volume). The inhomogeneous regions in the glass rod are preferably formed by phase separation and / or segregation of the glass components of the glass in which they are embedded.

[0162] That is, for example, droplet-like segregation zones or regions may occur in a glass having a first refractive index, with a second refractive index deviating from the first refractive index, and these segregation zones or regions are formed from some of the glass components of the base glass having the first refractive index. As a result, these segregation regions with refractive index have a different composition than the surrounding glass, and therefore may have different physical properties, such as even a different refractive index and / or a different coefficient of expansion.

[0163] Preferably, the glass in which the inhomogeneous regions are embedded as scattering centers is made of an As-Pb-containing silicate glass. In this case, the inhomogeneous regions may have a higher Pb and / or As content than the surrounding glass matrix. Alternatively, the glass in which the inhomogeneous regions are embedded as scattering centers is preferably made of a fluorine-containing Ca-Zn silicate glass. In this case, the inhomogeneous regions may have a higher fluorine content than the surrounding glass matrix of the rod.

[0164] A drawing process can then produce a glass rod having the desired distribution and concentration of scattering centers, which can then be cut to appropriate lengths and a subsequent heating process can be applied to the sections thus produced to deform them into the desired external shape.

[0165] The methods of manufacturing the diffuser body described herein can in principle also be applied to other glass types, for example borosilicate glass systems.

[0166] The resulting diffuser body can then be securely connected to the light guide by gluing or splicing.

[0167] By providing a dipping process before or after connecting the diffuser body to the light guide, a jacket can be advantageously produced that completely surrounds the diffuser body. It is advantageous to perform the dipping after connecting the diffuser body to the light guide, since it is advantageous for the durability of the connection points if they are also protected by a jacket. In this way, it is possible to surround the connection zone between the diffuser body and the light guide, for example the splicing area.

[0168] Here, as explained above, the jacket may comprise a layer of liquid silicone, a thermoplastic polymer, a melt-type adhesive, a two-component adhesive or a sol-gel glass that is transparent or semi-transparent to the light emitted laterally from the diffuser element, a shrink tube or even an additionally attached transparent or translucent mounting element, which at least partially or regionally or even completely surrounds the diffuser body and / or the transition point between the diffuser body and the light guide.

[0169] In the case of LAS glass-ceramics, for example, temperature control during ceramization can induce a crystal transformation from the originally clear, transparent, high-quartz mixed phase to the scattering-centered, opaque keatite phase.

[0170] Furthermore, a method for at least partially or regionally structuring, in particular for adapting the radiation intensity profile of a diffusing body, is also disclosed, in which the diffuser body and / or the connection zone to the light guide are at least partially or regionally, or even completely, surrounded by a transparent or translucent jacket and form a diffuser element.

[0171] The jacket is preferably formed from a flexible tube, preferably comprising scattering centers forming therein and / or thereon structures in almost any geometric shape and arrangement that at least locally modify the properties and / or composition and / or remove or apply material within the volume and / or at the surface, including: laser processing processes, in particular with short-pulse lasers or CO2 lasers, which preferably result in a modification of the refractive index and / or composition or in the creation of structures in the volume and / or on the surface; - printing processes with printable organic or ceramic dyes containing corresponding pigments or dyes based on glass fluxes, in particular for applying or producing grid profile structures, - Wet or dry chemical etching process, - photolithography process, - Polishing, mechanical machining processes, or a combination of these processes Includes:

[0172] A preferred use of the illumination system as described above in its various embodiment variants provides for use in photodynamic therapy (PDT), for example for treating tumors in the brain, lungs, airways, bladder or uterus. Also conceivable are uses as described at the beginning, for example for intravenous laser treatment (EVLT), for treating varicose veins, for laser interstitial thermotherapy (LITT), or for applications in the dental field, for treating the bladder or prostate, for light-induced treatment of inflammation (mucositis) of the neck / pharynx, for applications in the ophthalmology and dermatology fields. In the dental field, in particular applications in wound treatment or periodontal treatment should be mentioned here, where such a diffuser allows the gingival sulcus to be illuminated accordingly efficiently. In ophthalmology, this allows the provision of a probe, which can be inserted into the eyeball during procedures in the retina area, so that a large area of ​​the retina can be illuminated uniformly. Furthermore, there are applications in brain research, where pathological conditions can be treated by stimulating individual brain areas with light.

[0173] A further use of the illumination system as described above in its various embodiment variants provides for use in photodynamic therapy (PDT) or photoimmunotherapy (PIT) for treating tumors, where at least one light guide with a diffuser element captures light emitted from another diffuser element and transmits this light through the light guide to a detector for spectroscopic analysis. Here, in addition to various light-emitting diffuser light guides, light-receiving diffuser light guides are also applied to the patient, whereby the response to the PDT treatment can be estimated based on the spectral difference between the input coupled light and the received light (see Finlay et al., Proc. SPIE Int. Soc. Opt. Eng. 2014, June 14; 5315: Page 132-142). PIT treatment is described in particular in the US National Library of Medicine's "Study of RM-1929 and Photoimmunotherapy in Patients With Recurrent Head and Neck Cancer".

[0174] From the point of view of dosimetry in PDT or PIT treatment, the above-mentioned diffuser elements can also be used to detect light returning from the tissue due to scattering. Thus, on the one hand, it is possible to carry out spectroscopic examinations, especially if the backscattered light is analyzed at a wavelength different from that of the incident light. Thus, for example, it is possible to detect the extent to which a photosensitizer has reacted completely. On the other hand, intensity measurements can also provide information on the extent to which the tumor-affected tissue has been sufficiently or not over-irradiated.

[0175] Furthermore, industrial applications for inspecting hard-to-reach places, e.g. on or in machines where uniform illumination is particularly important, or spectroscopic applications or in biochemistry where biochemical in vitro reactions are stimulated by light are also advantageous.

[0176] The invention is explained in more detail below on the basis of exemplary embodiments shown in the drawings. [Brief description of the drawings]

[0177] [Figure 1] Schematic of an illumination system with light guide and diffuser elements for PDT applications. [Figure 2a] 1A-1D are schematic diagrams of various geometric configurations of a diffuser element. [Figure 2b] 1A-1D are schematic diagrams of various geometric configurations of a diffuser element. [Figure 2c] 1A-1D are schematic diagrams of various geometric configurations of a diffuser element. [Diagram 3] FIG. 2 is a detailed schematic diagram of a cross section of a diffuser element and a light guide. [Figure 4] Graph showing angle-dependent intensity profile. [Diagram 5] Further graphs showing the intensity profiles and respective specific scattering lengths of two different scattering diffuser bodies. [Figure 6] Schematic diagram of a diffuser element formed as a balloon catheter. [Figure 7a] FIG. 13 illustrates diffuser elements of different lengths. [Figure 7b]FIG. 13 illustrates diffuser elements of different lengths. [Figure 7c] FIG. 13 illustrates diffuser elements of different lengths. [Figure 8] Further graphs showing the angle dependent intensity profile of the diffuser element shown in Figures 7a-7c, including a schematic illustration of the measurement principle. [Figure 9] 4 is a further graph of a spherical diffuser formed as a sphere and having different thermal pre-treatments on the diffuser material. [Figure 10] FIG. 1 illustrates a diffuser shaped substantially as a sphere. [Figure 11] FIG. 13 shows an SEM image of a diffuser formed as a sphere, taken along a cross section at the center of the sphere. [Figure 12] FIG. 13 shows a further SEM image of a cross section of the diffuser in the near-surface zone.

[0178] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following detailed description of the embodiments, the same reference numerals in the accompanying drawings respectively represent the same components or components having the same function.

[0179] The following definitions are provided for ease of understanding:

[0180] For the purposes of the present disclosure, the term illumination system encompasses illumination devices which are particularly suitable for use for medico-technical purposes and which are at least locally disinfectable and / or sterilizable, especially when they come into contact with living tissue.

[0181] The reference "for a medico-technical treatment and / or diagnostic system" also encompasses the use or application of the illumination system disclosed herein as a medical treatment and / or diagnostic system per se.

[0182] 1 shows a schematic diagram of an arrangement of an illumination system 1 according to one preferred embodiment of the invention, where a medico-technical PDT application is shown by way of example.

[0183] In the example shown, the illumination system 1 comprises a laser light source 10 which, in the operating state, emits light in a given spectral range. For PDT applications, as mentioned at the beginning, lasers are used which emit at wavelengths matched to a given biochemically modified dye (photosensitizer), usually in the visible range, for example in the green spectral range at 532 nm, or in the red spectral range at 690 nm.

[0184] At its proximal end, the light guide 30 is connected to the laser light source 10 by a connector 20. Here, the proximal end refers to the end of the light guide 30 where the light is in-coupled. At the distal end, the light guide 30 comprises a diffuser element 40. This diffuser element 40 is introduced into the tumor tissue 60 formed in the healthy tissue 50, either directly or, optionally, via a cannula, not shown here. Here, the distal end refers to the other end of the light guide 30, which is usually located away from the proximal end of the light guide 30 and from which the light is specifically emitted.

[0185] Here, laser radiation reaches the diffuser element 40 by optical input coupling 41 at the diffuser element 40, where it is scattered multiple times and emitted substantially radially and spherically through the surface of the diffuser element 40. In the illustrated example, the optical output coupling is merely indicated by an exemplary light ray 42. Here, it is important that the emission into the sphere surrounding the diffuser element 40 is as uniform as possible. In particular, intensity peaks should be avoided. After the treatment, the tumor tissue 60 ideally necroses due to the light-induced biochemical reactions mentioned at the beginning.

[0186] Typically, a quartz fiber is used as the light guide 30 and the connector 20 is typically formed as a coaxial plug-in connector, a so-called SMA connector, in which the fiber is glued into the connector 20. Connectors 20 with a nickel silver sleeve can also be advantageous in terms of heat resistance, whereby the light guide 30 is introduced or pressed into the nickel silver sleeve by form-fitting through plastic deformation. Furthermore, in the case of larger laser powers, connectors 20 can also be used in which the fiber end of the light guide 30 is protected by a conical prism. This can be advantageous in the case of misalignments.

[0187] 2a-2c show, by way of example, various preferred geometric forms of such a substantially spherically radiating diffuser element 40 in schematic form. In FIG. 2a, a diffuser element 40 having a substantially spherical shape is shown. In FIG. 2b, an example of a diffuser element 40 formed as an ellipsoid is shown. In FIG. 2c, an example of a diffuser element 40 formed as a short cylindrical section is shown. It should be noted here that other shapes are also encompassed here, for example droplet-like or elliptical shapes, or shapes that can be represented as a superposition or combination of the basic geometric shapes mentioned above. A dome-like shape is also conceivable. Here, it is characteristic that the total length of the diffuser element 40 is rather short compared to the outer diameter of the light guide 30. Typically, the outer diameter of the light guide 30 is between 300 μm and 800 μm for the quartz fibers used, so that the typical length of the diffuser element 40 according to the invention is between 200 μm and a maximum of 10 mm. In FIG. 3, a detailed schematic view of the diffuser element 40 and the cross section of the light guide 30 is shown.

[0188] The fixing of the diffuser body 43 and the light guide 30 takes place in the connection zone 44, for example by a splicing process or by a gluing process using a highly transparent adhesive with a matched refractive index. In the case of splicing, the light guide 30 and the diffuser body 43 are partially melted and fused together by corona discharge and / or a laser, typically a CO2 laser. Depending on the materials used for the diffuser body 43 and the light guide 30, it may be necessary to use an intermediate medium 45 in order to match their thermal expansion coefficients. In the case of, for example, glass / quartz glass fusion, this intermediate medium 45 may be a solder or transition glass, or an optical glue or cement.

[0189] In the above applications, the light guide 30 typically consists of quartz glass having a core 31 with a refractive index n1 and a core diameter DC 31.1 typically between 200 and 800 μm, and a cladding 32 with a refractive index n2, where n1>n2.

[0190] Such fibers usually also have an outer polymer layer, called a buffer, for example made of polyamide or polyimide, which typically results in a numerical aperture NA of about 0.22. The optical input coupling 41 is performed through an input coupling surface formed by a connection zone 44 of the diffuser body 43.

[0191] As shown exemplarily, the diffuser body 43 can have an elliptical cross section. As already shown (see Figs. 2a-2c), the diffuser body 43 can also have various shapes. Geometrically characteristic is the diameter DD 43.1 of the diffuser body 43 (meaning its extent perpendicular to the direction of light input coupling, i.e. perpendicular to the longitudinal direction of the light guide in the region of the input coupling) and, if the diffuser body 43 is, for example, of rather elliptical or elliptical form, the diffuser length LD 43.3 along its longitudinal axis 43.2, i.e. parallel to the direction of light input coupling or parallel to the longitudinal direction of the light guide in the region of the input coupling.

[0192] According to the invention, as mentioned above, the diffuser body 43 consists of an inorganic material, in particular a glass, glass ceramic or glass-like material, which, due to its composition, allows the targeted formation of finely distributed scattering centers with a defined size distribution. The above-mentioned material approach is particularly suitable for this purpose.

[0193] For protection purposes, the diffuser body 43 is provided with a jacket 46 which completely surrounds the diffuser body 43, whereby it can be advantageous if the connection zone 44 between the diffuser body 43 and the light guide 30 is additionally also surrounded. Usually, the light guide 30 does not have a buffer layer in this region (shown without cladding 32 in FIG. 3), and therefore this zone can be protected by such a jacket 46, which would otherwise have to undergo a so-called recoating process for mechanical protection.

[0194] Here, the jacket 46 can consist of a varnish layer, a shrink tube or an additionally attached transparent or translucent mounting element such as a layer of liquid silicone, a thermoplastic polymer, a melt-type adhesive, a two-component adhesive or a sol-gel glass that is transparent or semi-transparent to the light emitted laterally from the diffuser element, which surrounds the diffuser body 43 and the transition point between the diffuser body 43 and the light guide 30.

[0195] It is contemplated that lower melting glasses may be included, but care should be taken to ensure that the emission characteristics of the diffuser element are not adversely affected when the lower melting glasses are applied at higher temperatures.

[0196] In an advantageous embodiment, the diameter DD 43.1 of the diffuser body 43 is designed to be larger than the core diameter 31.1 of the light guide 30 or the fiber bundle diameter 31.1, so that the light is optimally in-coupled into the diffuser body 43. On the one hand, this makes it possible to facilitate the assembly and adjustment of the light guide 30 and the diffuser body 43 and / or to compensate for assembly tolerances. What can be further achieved is that it is still possible to obtain a certain amount of light propagation towards the rear, i.e. in the direction of the light introduction by the light guide.

[0197] 4 shows the intensity profiles of two diffuser bodies 43 formed as rod-like materials for the purpose of empirically determining the specific scattering lengths 107.1, 107.2 in a graph 100. A first intensity profile 106.1 and a second intensity profile 106.2 are shown for the connection zone I (x) 44 or the intensity 101 measured perpendicular to the rod axis as a function of distance from the optical input coupling point, which is on the left side of the graph 100, and where the intensity profiles 106.1, 106.2 are normalized to 100% directly at the optical input coupling point. In both cases, if scattering effects are constant over the length of the rod, the intensity 101 will decrease approximately exponentially according to the following relationship: I (x) = I0*exp(-X / LS) (1) where I0 represents the initial intensity at the optical input coupling point, and I (x) is the connection zone I (x) 44 is the measured intensity 101 as a function of distance from the

[0198] Here, the specific scattering lengths LS1, LS2 107.1, 107.2 are defined as the distances from the light input coupling point at which the light intensity drops to a value of 1 / e or 36.8%. Exemplarily shown is a diffuser body 43 with relatively strong light scattering (left diffuser body 43), which is represented by a steep intensity profile 106.1 and a correspondingly relatively short scattering length LS1 107.1. The diffuser body 43 shown on the right shows a weaker scattering effect, which is represented by a rather flat intensity profile 106.2 and a correspondingly relatively long scattering length LS2 107.2. According to the invention, by targeted temperature / time processes, as already explained above, the material of the diffuser body 43 can be adjusted with respect to its scattering properties and quantitative characterization can be performed by such measurements.

[0199] To obtain an ideal radially uniform intensity distribution, there are requirements with regard to the shape, in particular the diffuser diameter DD 43.1 and the diffuser length DL 43.3, which depend on the scattering properties of the diffuser body 43, and which can be empirically described, at least to a first approximation, by the specific scattering lengths LS1, LS2 107.1, 107.2. In this case, the core diameter DC 31.1 of the light guide 30 or the fiber bundle diameter also plays a role. The following geometrical relationships have been found to be suitable:

[0200] Furthermore, the radially spherical radiation characteristics are promoted by the extent of the diffuser body, whereby the maximum extent LD of the diffuser body in a first direction is not more than 10 times, preferably not more than 5 times, particularly preferably not more than 2.5 times, preferably not more than 2 times, particularly preferably not more than 1.5 times the extent DD of the diffuser body in a second direction perpendicular to this first direction.

[0201] In a particularly preferred embodiment, the extent of the diffuser body in a first direction is equal to the extent of the diffuser body in a second direction perpendicular to the first direction, thereby providing a spherical embodiment.

[0202] For the quartz fibres used, the outer diameter of the light guide is usually between 200 μm and 800 μm, so in a preferred embodiment of the invention a typical range for the diffuser element can be between 300 μm and 3 mm. The maximum extent LD of the diffuser body in one direction is between 200 μm and 10 mm, preferably between 250 μm and 4 mm, particularly preferably between 300 μm and 3 mm.

[0203] Preferably, further, for the core diameter DC, DD≧DC (2) where DC typically lies in the range 200 μm to 500 μm, preferably in the range 300 μm to 400 μm. The ratio of the core diameter DC 31.1 of the lightguide 30 or the fiber bundle diameter to the diameter OD 43.1 of the diffuser body is therefore advantageously ≦1.0, preferably 1.0 to 0.8. Depending on the desired emission characteristics, a ratio of ≦0.8 can also be provided.

[0204] For the diameter of the diffuser body 43 formed as a sphere or for the diffuser length LD 43.3 of a rather elongated diffuser body 43, the following geometrical conditions arise, with it being found that advantageous values ​​of LS occur when LS approximately coincides with the diffuser body length LD 43.3: LD≦LS and (3) LD≦3*DC, preferably LD≦2*DC (4)

[0205] As a result of such a geometrical choice, the graph 100 shown in Fig. 5 is obtained, where the intensity 101 is shown as a function of the observation angle 102 at equal distances around the diffuser element 40. The first intensity profile 103.1 shows the intensity measurement in a horizontal plane around the diffuser element 40. The second intensity profile 103.2 shows the result of the intensity measurement in a vertical plane orthogonal to the first horizontal plane around the diffuser element 40. As is clear, both intensity profiles 103.1 and 103.2 are within a narrow intensity tolerance range 104. Thus, typically obtained values ​​for this are less than ±20%, preferably less than ±15%, particularly preferably less than ±10%.

[0206] If the aforementioned geometrical relationship is not optimally selected, for example in a rather spherical shape where the specific scattering length LS is significantly larger than the diffuser length LD 43.3 or the diameter of the diffuser body 43, then a clear convexity will result in the intensity profiles 103.1, 103.2 in the region around 0°, i.e. in the forward direction of light propagation, In contrast, if the specific scattering length LS is significantly smaller than the diffuser length LD 43.3 or the diameter of the diffuser body 43 in a rather spherical shape, then a clear concavity can be seen in the intensity profiles 103.1, 103.2 at about 0°.

[0207] As a further exemplary embodiment, Fig. 6 shows a diffuser incorporated into a balloon catheter. Schematically shown is a diffuser element 40 spliced ​​to a light guide 30 formed as a quartz fiber as described above, which resides in a balloon 47 that can be inflated during treatment. It can further be provided that a cooling liquid, e.g. 0.9% saline or water, can be circulated around or over the light guide 30 via additional supply and drain channels (see liquid supply and drain 48.1, 48.2), which helps to significantly reduce heat input into the tissue, especially when using relatively high power lasers.

[0208] Figures 7a-7c show different shapes of diffuser element 40. Figure 7a shows a diffuser element 40 whose diffuser length 43.3 LD is about 0.5 mm after the rolling process. Figure 7b shows a diffuser element 40 whose diffuser length 43.3 LD is about 0.8 mm after the rolling process, and Figure 7c shows a diffuser element 40 whose diffuser length 43.3 LD is about 1.0 mm after the rolling process.

[0209] In the further graph 100 of FIG. 8, for the diffuser element 40 shown in FIGS. 7a-7c, the corresponding measured intensity profiles 103.1, 103.2, 103.3 are shown as azimuthal scans, whereby the respective intensity 101 is plotted as a function of the observation angle 102. The schematic diagram of FIG. 8 shows the measurement principle of the goniometer measurement. The diffuser element 40 is illuminated by a laser source 10 via a spliced ​​quartz fiber (light guide 30) and emits light radially / spherically. Here, the detector 108 orbits around the diffuser body 40 at a certain distance, in this case about 35 mm, whereby the intensity 101 is measured as a function of the observation angle 102. Here, in FIG. 8, the intensity profiles 103.1, 103.2, 103.3 are normalized to the highest measured intensity 101 (=100%). The measurement is performed with the following settings or using the following hardware: Goniometer measurement range: -145°~+145° Distance between detector 198 and diffuser element 40: 35 mm ·GIGAHERTZ OPTIK Optometer P-2000 Sensitivity function: 400nm~1000nm by radiometer Standard sensitivity: 10nA / (W / m 2 ) Detector aperture (diffuser): 11mm · Measurement aperture cosine field of view Laser light source 10:4mW@655nm

[0210] The first intensity profile 103.1 shows the radiation characteristic of the diffuser element 40 shown in FIG. 7a, with a typical diffuser length LD 43.3 of 0.5 mm. Here, it is clear that this diffuser element 40 is relatively too short compared to its characteristic scattering length LS. This is evident from the pronounced intensity peak in the region around 0°. The second intensity profile 103.2 shows the radiation characteristic of the diffuser element 40 shown in FIG. 7b, with a typical diffuser length LD 43.3 of 0.8 mm. Here, it is clear that this diffuser element 40 is matched in terms of the diffuser length LD 43.3 compared to its characteristic scattering length LS, thus resulting in an almost uniform intensity 101. The third intensity profile 103.3 shows the radiation characteristic of the diffuser element 40 shown in FIG. 7c, with a typical diffuser length LD 43.3 of 1.0 mm. Here, it is clear that this diffuser element 40 is relatively too long compared to its characteristic scattering length LS. As a result, there is a significant drop in intensity in the region around 0°.

[0211] 9 shows a further graph 100 of a spherical diffuser formed as a sphere, where the diffuser material has been subjected to different thermal pre-treatments. The intensity profiles 103.1, 103.2, 103.3 of the relative intensity 101 as a function of the observation angle 102 are plotted.

[0212] The first intensity profile 103.1 exemplarily exhibits a more laterally radiating characteristic, corresponding to isotropy > 1. Here, the scattering behavior is adjusted very strongly such that radiation input-coupled into the diffuser is scattered laterally at a relatively early stage, with only a relatively small proportion passing through in the forward direction.

[0213] In contrast, the second intensity profile 103.2 shows a profile in which only a small percentage is scattered laterally and instead most of the input coupled optical power is transmitted in the forward direction, which corresponds to isotropy<1.

[0214] The third intensity profile 103.3 shows an example of nearly uniform radiation in each spatial direction, which corresponds to an isotropy of about 1. By targeted monitoring and control of the temperature / time process of the above materials, the intensity profiles 103.1-103.3 can be influenced.

[0215] The example shown is for CoralPor™ glass material as described above, where the laser wavelength is 655 nm.

[0216] A microscope image of the diffuser is shown in Figure 10, where the diffuser element 40 is formed substantially as or like a sphere, with a diffuser diameter 43.1 of about 1 mm. The light guide 30 has a fiber core diameter of about 400 μm, which corresponds to a ratio of the light guide core diameter to the diameter of the diffuser body 43 of about 0.4 in the example shown.

[0217] In Fig. 11, the sphere center of the diffuser body 43 of the diffuser element 40 of Fig. 10 is shown as a cross-sectional image in an SEM image, where the polished surface was etched with XeF2 gas prior to SEM imaging in order to distinguish the two different phases of glass in the polished surface. A through structure with a structure extent of about 200 nm is present in the sphere center, which becomes gentle from a few μm below the sphere surface towards the surface, forming a rather amorphous flat surface, as can be seen in Fig. 12.

[0218] For further mechanical protection and / or homogenization of the radiation characteristics, a further sleeve 49 made of transparent and / or translucent, colored or colorless material (silicone, glass or quartz glass) can be provided, which at least partially or regionally or completely surrounds the diffuser body and / or the jacket. In particular, further homogenization can be achieved by using translucent materials and / or materials containing scattering centers. For example, corresponding bodies or tubes made of silicone, Teflon or even polyether block amide block copolymers, known on the market, for example under the trademark PEBAX®, are suitable. As sleeve 49, a thin-walled shrink tube, for example made of PET, applied at least regionally, has proven effective, which can be finished in a single layer or in multiple layers.

[0219] It can be provided that between the diffuser body 43 and the sleeve 49, for example made of glass or plastic, a further layer is introduced between the sleeve 49 and the diffuser body 43 in order to suppress possible surface irregularities, such as for example dirt or roughness, on the diffuser body 43, which have a detrimental effect on the radiation behavior. Here, care must be taken on the one hand to have a refractive index that matches the glass system, a high transparency and a viscosity that is sufficiently high in terms of good applicability. For example glycerin or silicone (oil or adhesive) has been found to be suitable as further layer.

[0220] Thus, in one embodiment having a scattering element 43.6 formed using white glass, it is provided that scattering centers are formed in this white glass by scattering particles, and that the concentration of scattering particles in the scattering region is between 10 ppm and 1000 ppm, preferably between 20 ppm and 100 ppm.

[0221] The output coupling efficiency from the scattering region and thus from the volume of the white glass of the scattering rod or white glass tube depends not only on the scattering properties of the scattering particles as an intrinsic parameter but also on the concentration of the scattering particles in the scattering region itself.

[0222] Here, concentration data in ppm refers to the proportion of scattering particles relative to the mass fraction of the white glass component in which they are embedded.

[0223] An alternative embodiment arises where inhomogeneous regions of white glass act as scattering centers, said inhomogeneous regions being preferably formed by phase separation and / or segregation of glass components of the glass in which they are embedded.

[0224] The scattering centers formed by the inhomogeneous regions preferably have a diameter or maximum dimension of 10 nm to 1000 nm, particularly preferably 100 nm to 800 nm. These scattering centers are particularly preferably spherical.

[0225] The white glass in which the inhomogeneous regions are embedded as scattering centers may preferably consist of an As- and Pb-containing silicate glass, where the scattering centers have a high Pb and / or As content compared to the surrounding glass matrix.

[0226] The glass in which the inhomogeneous regions are embedded as scattering centers or the white glass may also consist of a fluorine-containing Ca-Zn silicate glass, in which case the scattering centers preferably have a high fluorine content compared to the surrounding glass matrix.

[0227] Depending on the materials used and the material properties of the scattering element 43.6 and the surrounding matrix 43.4, it is for example possible by gradient heat treatment to vary the scattering effect, for example continuously, by applying different temperatures along the direction of the diffuser's maximum extent, as a result of which it is possible, for example, to first set a rather low scattering effect for a volume region that is arranged directly at the input coupling face and a rather high scattering effect for a volume region of the diffuser body 43 on the opposite side.

[0228] This allows to obtain a diffuser body with scattering elements having scattering centers with different densities of scattering centers per volume unit in different volume regions, as a result of which possible intensity reduction in the direction parallel to the direction of input coupling of light can be at least partially compensated.

[0229] The intensity or intensity distributions disclosed in this specification and referred to in the claims correspond in physical terms to brightness, which is also called luminance or brightness when the measurements are made using an optical system, as in the present invention, and subtend a fixed solid angle. [Explanation of symbols]

[0230] 1. Lighting system 10 Laser light source 20 Connectors 30 Light guide 31 cores 31.1 Core diameter DC, or fiber bundle diameter 32 Clad 40 Diffuser element 41 Optical input coupling 42 Optical output coupling 43 Diffuser body 43.1 Diameter DD 43.2 Longitudinal axis 43.3 Diffuser length LD 44 Connection Zone 45 Intermediate medium 46 Jacket 47 Balloon 48.1 Liquid supply 48.2 Liquid drain 49 Sleeve 50 organizations 60 Tumor tissue 100 Graphs 101 Strength 102 Observation angle 103.1 First Intensity Profile 103.2 Second Intensity Profile 103.3 Third Intensity Profile 104 Strength Tolerance 105 Connection zone / distance from input coupling point 106.1 First Intensity Profile 106.2 Second Intensity Profile 107.1 Specific scattering length LS1 107.2 Specific scattering length LS2 108 Detector

Claims

1. 1. An illumination system (1), in particular an illumination system (1) for a medico-technical treatment and / or diagnostic system, comprising at least one laser light source (10) and a light guide (30) connectable and / or assignable at its proximal end to the at least one laser light source (10), and at a distal end of the light guide (30) a diffuser element (40) having a substantially radially spherical radiation characteristic, the diffuser element (40) comprising at least one diffuser body (43) comprising an inorganic material, in particular glass, glass ceramics, glass-like material or a composite material composed of the aforementioned materials, and advantageously at least one scattering element (43.6), the surface of the at least one diffuser body (43) being pore-free and smooth.

2. The lighting system (1) according to claim 1, wherein the at least one diffuser body (43) comprises a jacket (46), the jacket (46) at least partially or regionally or completely surrounding the diffuser body (43).

3. 3. The illumination system (1) according to claim 1 or 2, wherein the deviation of the radiant intensity distribution from the mean value is no more than ±30%, preferably no more than ±20%.

4. 4. The lighting system (1) according to any one of the preceding claims, wherein the at least one diffuser body (43) has a substantially spherical, elliptical, droplet-like, cylindrical shape or a shape combined from these basic shapes.

5. 5. The lighting system (1) according to claim 1, wherein the light guide (30) comprises a single fiber having a core (31) with a core diameter (31.1) and a cladding (32), and a diameter DD (43.1) of the diffuser body (43) in the region of the input coupling surface is greater than or at least equal to the core diameter (31.1) of the light guide (30) in the region of the input coupling surface.

6. 6. The lighting system (1) according to any one of the preceding claims, wherein the ratio of the light guide core diameter (31.1) to the diameter of the diffuser body (43) is ≦1.0 to 0.3, particularly preferably ≦1.0 to 0.

5.

7. 7. The lighting system (1) according to any one of claims 1 to 6, wherein the light guide (30) comprises a flexible fiber bundle or rigid fiber rod (31) having a fiber bundle diameter or fiber rod diameter (31.1), and a diameter DD (43.1) of the diffuser body (43) in the region of the input coupling surface is greater than or equal to the fiber bundle diameter (31.1) of the light guide (30) in the region of the input coupling surface.

8. 8. The lighting system (1) according to claim 1, wherein the ratio of the light guide fiber bundle diameter or fiber rod diameter (31.1) to the diameter of the diffuser body (43) is ≦1.0 to 0.3, particularly preferably ≦1.0 to 0.

5.

9. 9. The lighting system (1) according to any one of the preceding claims, wherein the at least one diffuser body (43) and the light guide (30) are rigidly connected to each other by gluing or splicing.

10. 10. The lighting system (1) according to claim 1, wherein a connection zone (44) is present between the diffuser body (43) and the distal end of the light guide (30), and an optical element and / or an intermediate medium (45) is arranged in the connection zone (44).

11. The lighting system (1) according to any one of the preceding claims, wherein the jacket (46) surrounds at least the connection zone between the diffuser body (43) and the light guide (30).

12. 12. The lighting system (1) according to claim 1, wherein the jacket (46) comprises a layer that is transparent or semi-transparent to the light emitted laterally from the diffuser element, the layer comprising an organic varnish, a liquid silicone, a thermoplastic polymer, a melt-type adhesive, a two-component adhesive or a sol-gel glass, a shrink tube or an additionally attached transparent or semi-transparent mounting element.

13. 13. The lighting system (1) according to claim 12, wherein the jacket (46) comprises a low-melting glass, which has a low processing temperature, advantageously below 500°C, preferably below 400°C, particularly preferably below 300°C, and / or the processing temperature of the applied glass is at least 50K, preferably at least 100K, lower than the softening temperature of the diffuser element.

14. 14. The lighting system (1) according to claim 12 or 13, wherein the jacket (46) is finished off with a transparent or light-scattering mounting cap made of plastic or glass.

15. 15. The lighting system (1) according to claim 1, wherein the diffuser body comprises scattering centers in the form of pores, particles, crystallites, polycrystallites, porous and / or colored and / or optically active pigments, in particular phosphorescent or fluorescent and / or luminescent bodies with colored regions, e.g. colored particles, colored crystallites or colored pigments or colorants of glass, or inhomogeneities in the form of refractive index variations, or any combination of such scattering centers, the inhomogeneities of the inorganic material comprising phase separations, segregations and / or particle inclusions, nuclei and / or crystallites.

16. 16. The illumination system (1) according to claim 15, wherein the concentration of the scattering centers in the scattering region is between 10 ppm and 1000 ppm, preferably between 20 ppm and 100 ppm.

17. 17. The illumination system (1) according to any one of the preceding claims, wherein the diffuser body (43) has a uniform distribution of scattering centres throughout its volume.

18. 18. The illumination system (1) according to any one of the preceding claims, wherein the scattering centres have a diameter or maximum extent in one direction of 10 nm to 5000 nm, particularly preferably 100 nm to 1200 nm.

19. The scattering particles are SiO ２ and / or SiN and / or BaO and / or MgO and / or ZnO and / or Al ２ O ３ and / or AlN and / or TiO ２ and / or ZrO ２ and / or Y ２ O ３ and / or only the metals of said oxides and / or BN and / or B ２ O ３ 19. The lighting system (1) according to claim 1 , further comprising: and / or Ru and / or Os and / or Rh and / or Ir and / or Ag and / or Au and / or Pd and / or Pt and / or diamond-like carbon and / or glass ceramic particles.

20. 20. The lighting system (1) according to any one of the preceding claims, wherein the at least one diffuser body (43) comprises a silicate glass, preferably a Na-Al-K silicate glass, very particularly preferably a Na-Al-K-Ca-Zn silicate glass or a Na-Al-K-As-Pb silicate glass.

21. The at least one diffuser body (43) comprises a borosilicate glass, which advantageously has the following composition (in weight percent): B ２ O ３ 15.00~40.00 Yes ２ 45.00~80.00 R ２ O 0.0~20.0 R'O 0.0~20.00 R’’O ２ 0.0~10.00 <h2 style=";text-align:left;direction:ltr">Al<h2 style=";text-align:left;direction:ltr"> ２ <h2 style=";text-align:left;direction:ltr"> O<h2 style=";text-align:left;direction:ltr"> ３ <h2 style=";text-align:left;direction:ltr"> 10 ...

19. The lighting system (1) according to any one of the preceding claims, comprising:

22. 19. The lighting system (1) according to any one of claims 1 to 18, wherein the at least one diffuser body (43) comprises a glass ceramic, preferably a lithium aluminosilicate glass ceramic (LAS-GC), a cordierite glass ceramic or a magnesium aluminosilicate glass ceramic, particularly preferably a clear and transparent lithium aluminosilicate glass ceramic which has been at least partially converted into a state having light-scattering crystallites by targeted temperature / time application.

23. 23. The lighting system (1) according to any one of the preceding claims, wherein the diffuser element (40) and / or the diffuser body (43) and / or the jacket (46) have low absorption at the respective application wavelengths.

24. 24. The lighting system (1) according to claim 1, wherein the diffuser element (40) and / or the diffuser body (43) and / or the jacket (46) are at least partially or regionally structured within their volume and / or on their surface.

25. 25. The lighting system (1) according to claim 1, wherein the diffuser body (43) and / or the jacket (46) have a coating made of scattering particles and / or the diffuser body (43) has an additional sleeve made of colored glass or colored plastic.

26. 26. The lighting system (1) according to any one of claims 1 to 25, wherein the diffuser element (40) and / or the diffuser body (43) and / or the jacket are covered by an inflatable transparent or light-scattering balloon (47).

27. 17. The lighting system (1) of claim 16, wherein a cooling liquid or gas can be made to flow around the diffuser element (40) and / or the diffuser body (43) within the balloon (47), and further supply and exhaust channels for the cooling liquid are provided in addition to the light guide (30).

28. A method for producing a diffuser body (43), in particular for an illumination system (1) according to any one of claims 1 to 27, comprising the steps of: - providing a glass melt from glass frits having a predetermined composition for producing a starting glass, advantageously a silicate glass, preferably a Na-Al-K silicate glass, very particularly preferably a Na-Al-K-Ca-Zn silicate glass or a Na-Al-K-As-Pb silicate glass, - adding scattering particles as scattering centers or generating scattering centers in the material by chemical and / or thermal processes, preferably with a diameter of 10 nm to 2000 nm, particularly preferably 100 nm to 1200 nm; homogenizing the melt until the desired concentration is obtained, preferably between 10 ppm and 1000 ppm, particularly preferably between 20 ppm and 100 ppm; - drawing said starting glass into a glass rod, said glass rod having a diameter preferably in the range from 0.1 mm to 5 mm, preferably in the range from 0.2 mm to 2 mm; - cutting the glass rod obtained; - Deforming the section by a subsequent heating process. A method comprising:

29. A method for producing a diffuser body (43), in particular for an illumination system (1) according to any one of claims 1 to 27, comprising the steps of: - providing a glass melt from glass frits having a predetermined composition for producing a starting glass, preferably a borosilicate glass, preferably an alkali borosilicate glass, - in a temperature range of 500 to 800°C, for example 600 to 800°C, preferably 650 to 750°C, particularly preferably 700 to 725°C, with a controlled temperature / time profile for phase separation, - for a period of 1 to 150 hours, for example 24 to 48 hours or 48 to 80 hours performing a heat treatment; - by the heat treatment scattering centers are generated in the material, in which the composition separates into a silicate-rich phase and a boron-rich phase, and an acid leaching step and / or a pore-cleaning caustic leaching step creates open porosity within the glass, whereby dispersed phase particles or pores of the order of 200-700 nm, for example 200-500 nm, preferably 300-500 nm, particularly preferably 300-450 nm, and about 100-450 nm are formed. ８ ~10 １２ mm －３ , preferably 10 ９ ~10 １１ mm －３ , particularly preferably 10 １０ ~10 １１ mm －３ and obtaining a glass having a number density of A method comprising:

30. A method for producing a diffuser body (43), in particular for an illumination system (1) according to any one of claims 1 to 27, comprising the steps of: - Providing a glass melt from glass frits having a predetermined composition for producing starting glasses for glass ceramics, preferably lithium aluminosilicate glass ceramics. where The starting glass is cerammed in a heating process, thereby allowing targeted adjustment of the crystallite size and their distribution within the volume of the diffuser body by crystal formation and growth, and the crystallites act as scattering centers.

31. A method for producing a diffuser body (43) according to any one of claims 27 to 29, characterized in that by temperature / time management a wavelength dependent scattering effect is obtained.

32. A method for manufacturing a diffuser body (43) according to claim 31, wherein the diffuser body thus obtained is firmly connected to the light guide by gluing or splicing.

33. A method for manufacturing a diffuser body (43) according to claim 31 or 32, comprising subjecting the diffuser body and / or the diffuser body connected to the light guide, including at least the connection zone between the diffuser body and the light guide, to a coating process to form a jacket (46).

34. A method for at least partially or regionally structuring, in particular for adapting the transverse radiation intensity profile of a diffuser body (43), said diffuser body (43) and / or a connection zone (44) being at least partially or regionally surrounded by a transparent or translucent jacket (49) and forming a diffuser element (40), preferably said jacket (49) being formed from a flexible tube, preferably said tube comprising scattering centers, which in a volume and / or on a surface form structures at least locally modifying their properties and / or composition and / or removing or applying material, in almost any geometric shape and arrangement, - laser processing processes, in particular short pulse lasers or CO2, which preferably result in a refractive index and / or composition modification or the creation of structures within said volume and / or at said surface. ２ Laser processing process using lasers, printing processes, in particular for applying or producing grid profile structures, with printable organic or ceramic colourants containing corresponding pigments or colourants based on glass fluxes; - wet or dry chemical etching processes, - photolithography process, - Polishing, mechanical machining processes or a combination of these processes A method comprising:

35. 28. Use of the illumination system (1) according to any one of claims 1 to 27 as a component of an apparatus for medical therapy, in particular for photodynamic therapy (PDT) and / or photoimmunotherapy (PIT) for treating tumors, for intravenous laser therapy (EVLT) for treating varicose veins, for bladder or prostate treatment, for laser interstitial thermotherapy (LITT), for light-induced treatment of neck / pharynx inflammation (mucositis) or for applications in the fields of dentistry, ophthalmology and dermatology.

36. 28. Use of an illumination system (1) according to any one of claims 1 to 27 as a component of a device for photodynamic therapy (PDT) for treating tumors, wherein at least one light guide (30) with said diffuser element (40) captures light emitted from another diffuser element (40) and transmits said light via said light guide (30) to a detector for spectroscopic analysis and / or dosimetry.

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