Illumination systems with optical waveguide having diffuser elements

Abstract

To provide an irradiation system that protects healthy tissue, and desirably avoids damage to the tissue.SOLUTION: An illumination system for a medical technology therapy and / or diagnosis system comprises: at least one light source; an optical waveguide 30 connectable or assignable to the light source at a proximal end thereof; and an optical element configured as a diffuser element 40 and arranged at a distal end of the optical waveguide so that light from the optical waveguide can be injected into the optical element. The optical element advantageously has an outside at least sectionally covered with a reflector layer 43 that has a mirror layer. The optical element has a light reflecting area covered with the reflector layer and a light transmitting area without the reflector layer, so that light injected into the optical element is at least partially reflectable in the light reflecting area, and light can be emitted in the light transmitting range and the reflectance of the reflector layer exceeds 90% for at least one wavelength range.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a lighting system having at least one light source, a light guide, and an optical element, wherein the optical element is preferably configured as a diffuser element and is arranged at the distal end of the light guide to couple light from the light guide to the optical element.

Background Art

[0002] Such lighting systems are increasingly being used in the medical environment. Currently, the following main applications can be classified: · Photodynamic therapy (PDT) or photoimmunotherapy (PIT) for treating tumors, · Endovenous laser therapy (EVLT) for treating varicose veins, · Laser-induced interstitial thermotherapy (LITT), and · Other applications, especially in the fields of dentistry, ophthalmology and dermatology, or for the treatment of epilepsy.

[0003] Photodynamic therapy (PDT) is a minimally invasive treatment option for various cancerous diseases. PDT is understood as a treatment method for tumors and other tissue changes (e.g., angiogenesis) that combines light with light-activated substances. At the start of treatment, a photosensitive substance, so-called photosensitizer, is injected intravenously into the patient's blood vessels, where it accumulates inside or on the cancer cells. These natural photosubstances concentrate in tumor cells, causing strong photosensitivity. For this reason, during PDT treatment, multiple cannulas (typically up to eight) are inserted into the tumor tissue, each containing a single light source that must be spatially dispersed as much as possible across the tumor tissue. Laser light, usually with wavelengths in the visible spectrum, such as green light with a wavelength of 532 nm or red light with a wavelength of 690 nm, is used to irradiate the tumor tissue as uniformly as possible from the inside. In these cells, aggressive oxygen radicals are formed, which selectively destroy the tumor cells. Healthy cells, in contrast to diseased cells, should remain unaffected by this chemical reaction. The precise mechanism of action is described, in particular, in "Photodynamic Therapy of Cancer," Cancer Medicine, 2003. In contrast, in photoimmunotherapy (PIT), appropriately modified photosensitizers trigger an immune response on or within cancer cells, leading to the death of cancer cells upon light irradiation.

[0004] Regarding light sources, a distinction is usually made between cylinder diffusers, which provide forward-directed conical illumination, and spot diffusers, which provide spot radiators with radial light emission. In the case of cylinder diffusers, particularly uniform lateral radiation over their length is important in operation. The radiant intensity is the same within the range of uniformity requirements at all points along each line from the proximal end to the distal end in the axial direction, i.e., along the long axis, and also approximately the same within the range of uniformity requirements at all points along each surrounding line in the radial direction, i.e., along the long axis, thus the cylinder diffuser acts almost as a Lambertian radiator.

[0005] At the same time, it is advantageous if high scattering efficiency can be achieved to ensure the lowest possible heat input into the tissue. In this case, radiation directed forward, especially from the distal end, should be avoided. For PDT applications, the typical laser output is a continuous output of less than 5W, so a maximum of 100mW to 1000mW, and typically 200mW to 500mW, is emitted per centimeter of diffuser length.

[0006] Existing examples include diffuser elements made of thin silicon cylinders embedded with scattering particles. The German Patent Application Publication No. 10129029 (DE10129029 A1) describes a flexible apparatus for the thermoscaling of biological tissue using a laser beam, comprising a light guide for guiding the laser beam, the distal end of which is enclosed in a transparent or opaque sleeve tube protruding from the fiber end. However, this is very complicated and costly to manufacture with sufficient radiation uniformity because aggregates of scattering particles often result in radiation points with significantly above-average intensity.

[0007] Light guides with diffuser elements are used only once in some applications and are disposed of after each treatment. Therefore, there is a certain cost pressure regarding manufacturing costs. Consequently, reusable solutions are increasingly being considered. Such solutions must be processable, for example, disinfectable and / or sterilizable, in accordance with relevant known standards. Processing methods include, in particular, washing / disinfection with a strong basic solution and sterilization using an autoclave at temperatures up to 135°C and a typical vapor pressure of approximately 3 bar. Typically, such processing cycles range from tens to hundreds. This requires high requirements for heat resistance, chemical resistance, and even hydrolysis resistance.

[0008] In EVLT, the treating physician inserts a catheter into the affected vein through a small puncture site, which acts as a guide rail for the venous laser. Subsequently, the lateral radiation of laser energy using a diffuser intensely heats the inner wall of the blood vessel, thereby causing the vein to collapse and close. Thus, pathological reflux of venous blood is prevented. As a result, the vein hardens, degenerates, and can be removed from the body. Typically, a so-called ring or double-ring fire system is used as the light source. In this case, the radiating elements are often manually pulled through the venous section being treated at as constant a speed as possible for uniform treatment, which makes its application difficult because carelessness or prolonged presence in one place can lead to further cell damage.

[0009] LITT is a minimally invasive technique used for localized tumor destruction. In this technique, the tumor is punctured under imaging control (e.g., ultrasound / MRI), and one (or more) laser fibers are inserted into the lesion to harden it with thermal energy. Nd:YAG lasers (1064 nm) and diffuser tip applicators are particularly used. Laser power is approximately 5-8 W (see, in particular, "Laserinduzierte Interstitielle Thermotherapie (LITT) bei malignen Tumoren", BAEK and KBV 01 / 2002).

[0010] Further, particularly volume scattering diffusers, are described, for example, in European Patent Application Publication No. 3184885 (EP 3184885A1). This describes a diffuser for the end of a light guide fiber made of quartz glass, where the intention is to manufacture the diffuser by applying a scattering material to the distal fiber end of the light guide fiber and curing it. The drawback of such an approach is that this volume scattering approach causes a very exponential decrease in intensity. Porous materials are also undesirable from the viewpoint of processability in medical technology applications.

[0011] U.S. Patent No. 6810184 (US6810184 B2) describes an approach to manufacturing fibers having a fused diffuser tip that can be combined with other fibers, using nanoporous silicon dioxide-coated optical fibers. European Patent Publication No. 2062077 (EP2062077 A4), U.S. Patent Publication No. 2009 / 0204111 (US2009 / 0204111 A1), and German Patent Publication No. 102015119875 (DE102015119875 A1) describe diffusers in which a structure is incorporated into or applied to a fiber using a laser for manufacturing.

[0012] International Publication No. 2008 / 024397 (WO 2008 / 024397 A2) presents, in particular, a diffuser for delivering high-power density optical energy to a treatment site at the distal end of at least one optical fiber. In this diffuser, the scattering center is intended to be located at a predetermined length in the fiber core, or at a predetermined length within or near the interface between the fiber core and the cladding.

[0013] However, the aforementioned approach, especially when the scattering centers are sufficiently uniform, is expected to have the drawback that lateral emission will not achieve the uniformity required in a medical environment, based on an exponential decrease or non-uniform distribution of lateral emission.

[0014] U.S. Patent Application Publication No. 2009 / 0204111 describes a laser delivery system using optical fibers, comprising a core, a cladding layer covering at least a portion of the core and having a lower refractive index than the core, and non-characteristic sections and characteristic sections, the characteristic sections being characterized by allowing light to be extracted radially from the characteristic section to produce a desired radial light output pattern, wherein the characteristic sections are intended to be selected from the group consisting of a helical structure, a radial cross-section, an axial cross-section, and a combination thereof.

[0015] German Patent Application Publication No. 102015119875 describes an optical waveguide comprising a core for guiding light waves, a region within the optical waveguide, wherein fine modifications are arranged in the region within the optical waveguide, and the arrangement of the fine modifications is regular.

[0016] International Publication No. 2019 / 063799 (WO2019 / 063799 A1) describes a lighting system, particularly for medical technology treatment systems and / or diagnostic systems, comprising at least one laser light source, a light guide, the light guide being connectable to and / or assignable to the at least one laser light source at its proximal end, and having a diffuser element having a longitudinal axis at its distal end, the longitudinal axis extending into or within the diffuser element perpendicular to the coupling surface of the light guide. In this case, the diffuser element radiates light laterally with respect to its long axis over its effective length, wherein the diffuser element has at least one diffuser substrate, and the diffuser substrate includes at least one scattering element. In this configuration, the lighting system includes a device for uniformizing the radiant intensity along the long axis of the diffuser base, and in operation, the lighting system has a lateral radiant intensity distribution that deviates by a maximum of ±50%, preferably a maximum of ±30%, and most preferably a maximum of ±5% from the average lateral radiant intensity. Thus, a cylinder diffuser can be realized that radiates particularly uniformly over its length, and furthermore, has high efficiency and low self-heating, which is particularly advantageous for PIT and PDT applications.

[0017] As mentioned earlier, in many applications within the medical technology environment, healthy tissue directly adjacent to the tissue being irradiated is often also irradiated and subsequently damaged. Therefore, efforts are being made to protect these tissues from undesirable irradiation in the future. [Prior art documents] [Patent Documents]

[0018] [Patent Document 1] German Patent Application Publication No. 10129029 [Patent Document 2] European Patent Application Publication No. 3184885 [Patent Document 3] U.S. Patent No. 6810184 [Patent Document 4] European Patent Application Publication No. 2062077 [Patent Document 5] U.S. Patent Application Publication No. 2009 / 0204111 [Patent Document 6] German Patent Application Publication No. 102015119875 [Patent Document 7] International Publication No. 2008 / 024397 [Patent Document 8] International Publication No. 2019 / 063799 [Non-Patent Document]

[0019] [Non-Patent Document 1] "Photodynamic Therapy of Cancer", Cancer Medicine, 2003 [Non-Patent Document 2] "Laserinduzierte Interstitielle Thermotherapie (LITT) bei malignen Tumoren", BAEK and KBV 01 / 2002 [Summary of the Invention] [Problems to be Solved by the Invention]

[0020] Therefore, an object of the present invention is to provide improved irradiation of unhealthy tissues that meets special requirements in the medical technology environment and, in particular, protects healthy tissues, thereby avoiding undesirable damage to the human body and enabling irradiation. [Means for Solving the Problems]

[0021] The aforementioned problems are resolved by the subject matter of the independent claims. Further advantageous configurations are described in the dependent claims, respectively.

[0022] Therefore, the present invention relates to a lighting system for medical technology treatment and / or diagnostic systems, particularly for use in biological tissues, At least one light source, A light guide that can be connected to or assigned to the proximal end of the light source, Preferably an optical element configured as a diffuser element and positioned at the distal end of the light guide, The present invention relates to a system having a light guide capable of coupling light from the light guide to the optical element. In the sense of the present invention, a diffuser element is understood to be a light scatterer, in particular an object capable of guiding and, advantageously, radiating light in various directions. In this case, the light can be diffuse or directional, and can be radiated in directions that are oblique, perpendicular, or parallel to the direction in which the light is coupled to the optical element.

[0023] The optical element has a light-reflecting region on one side and a light-transmitting region on the other side, wherein the light-reflecting region has at least partial reflectivity, and the light-transmitting region has at least partial transmittance, particularly advantageously high spectral transmittance up to a wavelength of about 2.5 μm. Light coupled within the optical element can be at least partially reflected in the light-reflecting region. In this case, the reflection can be emitted diffusely or directionally. In the light-transmitting region, light, particularly the reflected light described above, can be at least partially extracted from the optical element. In particular, the light-reflecting region has a higher reflectivity than the light-transmitting region. Particularly preferably, the reflectivity of the light-reflecting region is at least 30, particularly at least 50, particularly at least 70 percent points higher than the reflectivity of the light-transmitting region. Advantageously, for this purpose, the optical element is at least partially covered with at least one reflector layer, particularly in the region of the light-reflecting region, thereby imparting at least partial reflectivity to the light-reflecting region. Advantageously, the optical element is provided with at least partial transmittance to the light-transmitting region by having no reflective layer at least partially, particularly in the region of the light-transmitting area. The reflective layer can cover the surface and / or outer surface of the optical element. Furthermore, the reflective layer may include a mirror layer or be intended to be configured as a mirror layer.

[0024] Therefore, the optical element may have an outer surface that is at least partially covered with a light-reflecting reflective layer, which preferably has a mirror layer, where the optical element has a light-reflecting region covered with the reflective layer and, preferably, a light-transmitting region without the reflective layer, so that the light emitted from the optical element is at least partially reflective and light can be emitted in the light-transmitting region. In particular, this allows light to be emitted as intended in the light-transmitting region. The term outer surface is understood in particular to mean one surface of the optical element.

[0025] Particularly preferably, the reflectivity of the reflector layer is greater than 90% for at least one wavelength range. The reflector layer may also be configured as a mirror layer.

[0026] The wavelength range designed for the aforementioned reflector layer may advantageously include the visible spectral range (VIS) of approximately 400 nm to approximately 700 nm, for example, particularly 400 nm to 450 nm or 600 nm to 700 nm, as well as the infrared range (IR) of approximately 700 nm to approximately 2.5 μm, particularly the near-infrared range (NIR) of approximately 700 nm to approximately 1200 nm, for example 980 nm or 1064 nm. Wavelengths of approximately 350 nm to approximately 400 nm in the near-ultraviolet range are also conceivable.

[0027] However, the light-transmitting or light-reflecting region may also be designed so that a predetermined wavelength range or a predetermined dominant wavelength is transmitted or reflected. Advantageously, this predetermined range does not exceed 20 nm, preferably not exceeding 10 nm, and preferably not exceeding 5 nm. Such a predetermined range may include, for example, wavelengths of a specific color, particularly green or red.

[0028] The optical element has at least a partial light-reflecting region on one side and at least a partial light-transmitting region on the other side, and the light-reflecting region has a higher reflectivity than the light-transmitting region, thereby advantageously achieving that light leakage is reduced or avoided in the light-reflecting region, while light leakage is increased or limited in the light-transmitting region. This advantageously enables more targeted light emission, particularly for irradiating diseased tissue while protecting adjacent healthy tissue.

[0029] In particular, by applying a reflective layer only in sections on the diffuser element, light is emitted as intended in the uncovered areas, thereby ensuring that only the lesion or the tissue to be irradiated is targeted during medical treatment, for example, in the range of LITT applications, the tissue is hardened as intended by the energy input. Adjacent healthy tissue is thus protected from irradiation and, ideally, remains undamaged.

[0030] In one embodiment, light can be radiated or extracted laterally across the long axis of the optical element and over the effective length of the optical element. If the optical element is configured as an optical waveguide, it can advantageously guide the light in a predetermined direction, for example, along the long axis. Within the scope of this disclosure, radiation having a directional component that starts from the long axis of the diffuser element and extends radially is understood as lateral radiation. The intensity of this irradiation is understood as the lateral radiation intensity.

[0031] In this case, the geometric shape of the radiation can be adapted by a corresponding geometric fit of the reflector layer so that, for example, a band-shaped or lens-shaped pattern can be projected onto the tissue surface being treated. Therefore, it is advantageous if at least one region of the diffuser element not covered by the reflector layer, for example, an interruption in the reflector layer, extends along the long axis of the diffuser element, and this uncovered region is light-transmitting, and the light guided by the diffuser element can be emitted in a band-shaped, especially linear, manner. In this case, the light-transmitting region can extend linearly or nonlinearly. A linear radiation region allows for localized radiation, so that the irradiated tissue can be irradiated over a larger area rather than as a point, and at the same time, this region can be kept within a defined boundary to protect the surrounding tissue.

[0032] By appropriately fitting the reflector layer, and in some cases combining it with the geometric shape of the optical element, complex radiation geometric shapes can be achieved. For example, gradual regions are possible, in which case the reflector layer may be weaker in the defined region, having particularly lower reflectivity than in the strongly reflected region. However, geometric shapes are also conceivable in which, for example, light-transmitting, particularly band-shaped regions, widen or narrow in one direction, for example, along the long axis. In this case, for example, band-shaped, lens-shaped, or elliptical regions along the long axis can be extended transversely and / or obliquely along the long axis of the optical element.

[0033] Ideally, the diffuser element is configured to be elongated or rod-shaped so that it can be inserted, for example, into a catheter. The diffuser element can also have a cross-section that is essentially circular, elliptical, or polygonal, such as a hexagon, rectangle, or square, and a star shape can also be realized. In this case, light is advantageously radiated laterally through facets or radial surfaces. Thus, a reflective layer applied to the diffuser element only in segments or facets allows light to be radiated laterally only in a specific direction or defined area. It is particularly advantageous if at least one or more facets have a lens-like shape, preferably a Fresnel lens shape, so that the light can be focused, especially allowing for stronger or higher-energy irradiation.

[0034] As described above, the diffuser element and / or optical element preferably have an elongated, rod-shaped, or cylindrical form, so that the diffuser element and / or optical element define a major axis. Therefore, the outer surface is preferably an outer surface that extends around the major axis. Thus, the normal vector of the outer surface in particular is perpendicular to the major axis.

[0035] As described above, the light-reflecting regions of the optical element and / or diffuser element, covered with a reflector layer, are intended to extend tangentially to the long axis over at least a specific angular range (e.g., at least 90°, 180°, or 270°), and similarly, the light-transmitting regions, which are advantageously without a reflector layer as described above, may also be intended to extend tangentially to the long axis over at least a specific angular range (e.g., at least 1°, 10°, or 20°). Thus, the light-transmitting regions can be configured, for example, as a wedge-shaped portion of the outer surface, but of course, as already described, they can also have more complex geometric shapes.

[0036] The reflector layer is provided particularly concentrically on at least a portion of the outer surface or on at least one facet. In this configuration, the reflector layer is advantageously configured to reflect light from the diffuser element back to the matrix of the diffuser element, and / or to reflect light from the outside back to the outside. This also means that the reflector layer is transparent to light from the outside, as it can be reflective on only one side, allowing light from the outside to be introduced into the diffuser element. Therefore, the reflector layer and / or mirror layer can be configured as dichroic mirrors, for example, short-pass mirrors, long-pass mirrors, narrow-band mirrors, or broad-band mirrors.

[0037] Advantageously, especially when light is incident perpendicularly to the reflector layer and the reflectance can be adjusted as desired to a defined wavelength of light used, or within a predetermined range around the dominant wavelength of light, the maximum reflectance is greater than 95%, and particularly preferably greater than 99%.

[0038] In an advantageous embodiment, the reflectance of the reflector layer is greater than 50% of the reflectance for perpendicular incidence, preferably greater than 70%, and most preferably greater than 90%, and especially in the range near the maximum reflectance for perpendicular incidence, when the angle of incidence of light with respect to the perpendicular to the reflector layer is greater than 45°, preferably greater than 60°, and particularly preferably greater than 80°. In other words, the reflectance can be greater than 50%, preferably greater than 70%, and preferably greater than 90% within a certain range, particularly within an angular range around the maximum reflectance for perpendicular incidence, advantageously within a predetermined angular range.

[0039] Advantageously, light is guided through the diffuser element within a predetermined wavelength range. However, different wavelengths have different reflectivity. Therefore, advantageously, a reflector layer having particularly high reflectivity for various wavelengths and / or a wide wavelength range is used, resulting in a flat region of multiple maxima or wavelength-dependent reflectivity maxima with respect to the light used, and corresponding wavelengths having particularly high reflectivity exceeding 90% even when light is incident at an oblique angle.

[0040] Therefore, reflectivity can be adjusted to match the wavelength and angle used. In this way, a particularly large amount of light can be reflected. This is especially important because light absorption should be avoided. Since the lighting system may operate at an output of up to 30 watts, typically 10-20 watts, absorption can cause strong heating of the diffuser element and / or reflector layer. Such high absorption, for example, due to overheating, can lead to damage to the lighting system, or in worse cases, even injury to people. Therefore, the lighting system should be kept cool during operation so as not to be damaged by high reflectivity. In other words, self-heating of the optical or diffuser element should be avoided, advantageously by reflecting the maximum amount of light.

[0041] The mirror layer, particularly the reflector layer, may have a metal layer or be composed of a metal layer, advantageously comprising one or more metals from the group of noble metals or one metal from the group of Mg, Al, Cu. Alloys of these materials are also conceivable. Based on high reflectivity over a wide wavelength range, noble metals, such as Au, Pt, Pd, or Ag, are preferably used. The workability of the manufacturing of the reflector layer is also relatively simple. Based on the low oxidizing properties of Au, it is inert to body fluids, for example, and has little interaction with self-proteins, so Au has particularly good biocompatibility and is therefore preferred. Overall, the reflector layer should meet requirements, particularly the standardized requirements of biocompatibility and cytotoxicity required in medicine, for example.

[0042] As described above, the outer surface of the diffuser element or optical element is covered at least partially with a reflector layer, which preferably includes a mirror layer. In further configurations, the reflector layer may be configured as a multilayer and / or layer system. In this case, for example, the mirror layer of the reflector layer may consist of multiple layers. However, a multilayer reflector layer may also include one or more additional layers present in addition to the mirror layer, and particularly positioned below and / or above the mirror layer. The preferred reflectivity of the reflector layer, as defined in more detail elsewhere, pertains to the entire reflector layer, i.e., the entire reflector layer including one or more mirror layers and one or more additional layers.

[0043] However, it is obvious that, alternatively or additionally, further layers, which do not belong to the reflector layer, may be provided below and / or above the reflector layer.

[0044] The reflector layer is configured as a layer system comprising at least one mirror layer and / or may have at least one of the following features: • Below the reflector layer, there is a base layer region consisting of a single layer or a series of layers. • At least one adhesion layer or adhesion promoter layer is provided between the diffuser substrate and the mirror layer. A layer region on the diffuser substrate having chemically and / or physically modified adhesion properties is provided between the diffuser substrate and the mirror layer. The reflector layer has at least one passivation layer that at least partially covers the reflector layer in the outward-facing region.

[0045] In other words, the reflector of the casing of a lighting system having at least one reflector layer can be configured as a layered system and / or may include at least one adhesion layer or adhesion promoter layer between a diffuser substrate, also referred to as a diffuser element, and the reflector layer, and / or a layered region on the diffuser substrate having chemically and / or physically modified adhesion properties.

[0046] As described above, in further configurations, the reflector layer can be configured as a multilayer or layered system, and in particular, the reflector layer may be intended to include at least one additional layer in addition to the mirror layer.

[0047] Accordingly, the reflector layer may have, in addition to the mirror layer, a lower layer below the mirror layer and / or an upper layer above the mirror layer, where the lower layer consists of one or more layers in particular, and the upper layer consists of one or more layers in particular.

[0048] The lower layer beneath the mirror layer is advantageously configured as an adhesion layer or an adhesion promoter layer.

[0049] The lower layer beneath the mirror layer is advantageously configured as a layer region on a diffuser substrate having chemically and / or physically modified surface properties.

[0050] The lower layer beneath the mirror layer is advantageously configured as a base layer region consisting of a single layer or a series of layers. Thus, the base layer region, for example, a base layer region beneath the mirror layer, particularly one that is part of a reflector layer, and / or a base layer region provided beneath a reflector layer, may include one or more layers applied to the optical element. Alternatively or additionally, the base layer region may include a surface layer of the optical element having modified surface properties, particularly one with increased surface energy and / or an increased number of oxygen radicals, said surface layer being manufactured or can be manufactured using chemical and / or physical processes to modify at least one surface property of the optical element. The base layer region, for example, a base layer region beneath the mirror layer, particularly one that is part of a reflector layer, and / or a base layer region provided beneath a reflector layer, may form an adhesion layer or an adhesion-promoting layer.

[0051] Therefore, the reflector layer or mirror layer can be placed directly on the diffuser element, that is, without using an adhesive layer in particular. In this case, a passivation layer may be placed on the reflector layer and / or mirror layer, but it is not essential. Thus, the diffuser element or reflector layer may be intended to be configured with or without an adhesive layer and / or passivation layer. An adhesive layer, or a layer region with modified adhesive properties, results in improved adhesion of the reflector layer to the optical element or diffuser element or diffuser substrate. This is particularly advantageous from the viewpoint of corrosion resistance of the reflector layer when the illumination system is used, for example, many times, and the reflector layer must withstand complicated cleaning and sterilization processes using corrosive acids and / or bases. Improved adhesion is also advantageous from the viewpoint of abrasion resistance, because, for example, friction may occur while the illumination system is moved inside a catheter, and the reflector layer remains securely attached to the diffuser substrate. However, it is also conceivable that the adhesive layer may be configured to actively contribute to reflection. In other words, the material, surface, and / or crystal orientation of the adhering layer are intended to be selected to reflect at least some of the light or predetermined wavelengths in relation to the properties of the optical or diffuser element.

[0052] Therefore, it is worth mentioning that the preferred reflectivity of a reflector layer including one or more additional layers in addition to the mirror layer, i.e., a base layer region and / or a passivation layer, is relevant to the entire reflector layer. In particular, layers applied to the optical element below the mirror layer and / or layers applied above the mirror layer can contribute to the reflectivity of the reflector layer. This is especially true for surface layers of the optical element below the mirror layer, which can be manufactured, for example, by chemical and / or physical processes. This is because these processes cause modification of the material of the optical element within the surface layer of the optical element, and thus can form part of the reflector layer.

[0053] The layer system may also be intended to have at least one additional passivation layer in the external region, which completely covers the reflector layer. The passivation layer provides additional protection against, for example, acids or other potentially corrosive media, such as gases or liquids. Furthermore, the passivation layer can improve the biocompatibility of the reflector layer with the biological or material substances on which the lighting system is used, thus protecting the patient being treated.

[0054] The lighting system is also intended to have at least one of the following features: • The lower layer (43.1), particularly the adhesion layer, adhesion promoter layer, or base layer region, is configured as a dielectric layer, where the dielectric layer preferably has an oxide, nitride, or oxynitride from at least one element from the group consisting of Si, Al, Ti, Zr, Hf, Y, and Zn. The upper layer (43.2), particularly the passivation layer (43.3), is configured as a dielectric layer, where the dielectric layer preferably has an oxide, nitride or oxynitride from at least one element from the group consisting of Si, Al, Ti, Zr, Hf, Y, and Zn.

[0055] Such materials are particularly suitable as adhesion promoter layers, especially for pure metal layers, for example, on glass. Furthermore, metal oxides and metal nitrides are highly corrosion-resistant to chemical and / or mechanical loads, such as abrasion. In particular, oxides of Ti and Zr have little interaction with bodily fluids, which results in high biocompatibility. Therefore, such materials are also particularly suitable as passivation layers.

[0056] In advantageous embodiments, the mirror layer or reflector layer is configured as a multilayer system of dielectrics having a series of low-refractive-index and high-refractive-index metal oxides and / or metal nitrides. Such layer systems are optimal and highly tunable or adaptable, particularly with respect to reflective properties, so that the design or layer system, and preferably the lighting system having the reflector layer, can be tailored to a specific application, and in particular, the reflected wavelength range can be precisely controlled.

[0057] In further embodiments, the mirror or reflector layer may be configured as a layer having scattering centers and may be finished in combination with a metallic reflector layer and / or dielectric layer, where any additional metallic reflector layer and / or dielectric layer externally at least partially surrounds the layer having scattering centers. In particular, the scattering elements can produce a reflective effect in a favorable direction at a particular concentration or thickness. In this case, in principle, the reflective effect increases with increasing concentration of scattering centers and with increasing thickness of the layer having scattering centers. An example of this is a layer having a white pigment or embedded with defects that scatter incident light. This any additional metallic and / or dielectric reflector layer can completely prevent light transmission to the outside.

[0058] It is also advantageous when the reflector layer is composed of a system of three, four, or more layers. In this way, the individual layers can be better aligned with each other, and in particular, the reflected wavelength can be tuned with great precision. The degree of reflectivity can also be favorably tuned in this way, so that particularly high reflectivity of the light used can be achieved. To increase reflectivity, it may also be intended to embed the mirror layer in a multilayer system, especially a dielectric layer system.

[0059] The thickness of the aforementioned layer may also be defined by at least one of the following characteristics: The thickness of the adhering layer is greater than 5 nm, preferably greater than 30 nm, and / or less than 3000 nm, preferably less than 300 nm, preferably less than 150 nm. The thickness of the mirror layer is greater than 10 nm, preferably greater than 20 nm, preferably greater than 50 nm, and / or less than 5000 nm, preferably less than 200 nm, preferably less than 100 nm. The thickness of the passivation layer is greater than 5 nm, preferably greater than 100 nm, preferably greater than 150 nm, and / or less than 5000 nm, preferably less than 500 nm, preferably less than 250 nm.

[0060] The adhesive layer is configured with a thin thickness to have as little, and especially minimal, influence on the reflectivity of the reflector layer. Accordingly, the thickness of the mirror layer is configured to a predetermined value so that light transmission is minimized and as little material as possible is used overall. The thickness of the mirror layer and / or reflector layer is adjusted so that wavelengths greater than, for example, 0.35 μm, preferably greater than 0.4 μm, more preferably greater than 0.8 μm, and / or less than 2.5 μm, preferably less than 1.6 μm, and preferably less than 1.2 μm are reflective. The thickness of the mirror layer and / or reflector layer is further specifically adjusted to the wavelength of use. Thus, the reflectivity can be adjusted according to the wavelength of use.

[0061] If the operating wavelength is, for example, 2 μm, the reflectance is optimized for a wavelength range of, for example, 1.9 μm to 2.1 μm or narrower, at 690 nm between 670 nm and 710 nm. In other words, the reflectance of the mirror layer and / or reflector layer is adjusted to a wavelength that deviates from the operating wavelength by up to 100 nm, preferably 50 nm, and preferably 20 nm. The thickness of the passivation layer is selected to ensure corrosion resistance.

[0062] As described above in various deformation modes, it is reasonable that the abrasion resistance or adhesion of the reflector layer be able to withstand at least normal or standardized abrasion and adhesion tests. Such tests can very well verify mechanical or physical corrosion resistance. Furthermore, given the stringent regulations in the medical field, it can be ensured that the lighting system can be used in the environment for which it is intended.

[0063] Good adhesion or physical resistance to mechanical influences can be examined, for example, by a so-called tape test. In this test, adhesive tape is applied to the coated optical element or reflective layer and peeled off at a defined angle. If the adhesive tape is not coated after peeling and the coating does not show delamination, the test is considered to have passed. It should be noted that the passivation layer, which may be present in some cases, is also resistant to the above-mentioned mechanical loads.

[0064] Mechanical abrasion resistance testing is the so-called eraser or rubber test. In this test, an eraser is moved back and forth multiple times over the layer being tested under a specific force. If no damage is observed on the layer being tested after this test cycle, the layer is considered abrasion resistant.

[0065] The passivation layer of the reflector layer may be configured as a barrier layer. Therefore, the passivation layer may be intended to prevent or block polymer components, such as acids and / or oxygen, and especially ions of acidic or alkaline solutions, from diffusing into the reflector layer, particularly onto or into the mirror layer. Thus, the passivation layer can slow down or prevent, for example, the penetration of acids, oxygen, or other components of air into the reflector layer.

[0066] In particular, when processing medical products, alkaline cleaning or disinfecting agents (e.g., Neodisher with a pH of approximately 11) may be used. Furthermore, sterilization methods using ethylene oxide are known and are used especially for disposable items. Here again, chemical resistance to this gas should be ensured. For autoclaving (typically at 135°C / 3 bar), even better hydrolysis resistance is required.

[0067] Furthermore, rinsing solutions containing sodium hypochlorite (NaClO), bleach, or disinfectant may be used, in which case the passivation layer must be at least chemically resistant to such substances. This is particularly relevant for applications in the field of dental medicine.

[0068] Advantageously, the passivation layer or reflector layer also has a hardness of, for example, at least 800 HV (Vickers hardness), advantageously at least 1200 HV, and particularly preferably at least 2000 HV, according to conventional or standardized test methods for determining the hardness of the layer. Thus, the passivation layer can also be configured as a mechanical protective layer for the mirror layer or reflector layer, and especially for the metallic mirror layer. In particular, hard materials made of carbides or nitrides are protected based on their high hardness, for example, AlN: up to about HV 2000, Si3N4: up to about HV 2500.

[0069] Furthermore, the reflector layer is positioned at the distal end of the diffuser element and / or is intended to at least partially cover the diffuser element. It is obvious that the reflector layer applied to the distal end of the diffuser element may also have an adhesion layer and / or a passivation layer. The reflector layer can also be understood as a reflector surface, where the reflector surface is configured as a reflective layer of dielectric sputtered or deposited on the distal end of the diffuser substrate, the layer consisting of multiple layers and tuned with respect to the wavelength of light used with respect to reflectance, where, advantageously, there is a reflectance maximal at this wavelength. Ideally, the reflector surface has the form of a directional reflector, e.g., a metallic mirror surface with a metallic coating including Al, Ag, Au in particular, or a diffuse reflector including, for example, a white layer, which reflects back the light that has passed through the diffuser substrate. This can at least partially compensate or correct the normal exponential decrease in the intensity of light radiated laterally along the diffuser substrate. This allows for the homogenization of lateral radiation, as the amount of light that can be provided with a constant scattering rate can be varied or adapted at least intermittently.

[0070] Furthermore, a reflective dielectric layer sputtered or deposited on the distal end of the diffuser substrate has proven particularly advantageous, as this layer can consist of multiple layers and can be tuned with respect to the wavelength of light used, meaning it can have a maximum at the tuned wavelength. This allows for ideal back reflection of the coupled light or its wavelength in the operating state, on the one hand, and avoidance of hot spots, on the other hand. Alternatively, reflectors can be made from a silver layer that reflects well over a broadband and has passivation on the back. This is particularly robust and can suppress unwanted reflections that could lead to excessive localized intensity increases and thus hot spots. This enables the creation of very broadband reflectors with very good reflective properties, especially in the visible spectral range (VIS) and in the IR / MIR range, e.g., wavelengths of 1 μm to 2.5 μm. Passivation on the back prevents oxidation of the silver layer.

[0071] When the reflecting surface is configured as concave or convex, the reflected light rays are reflected back at least partially along a path nearly parallel to the long axis and / or at a steep angle to the long axis, thereby being scattered more frequently by the scattering element. This can be achieved to increase the efficiency of extracting lateral radiation to the distal end of the diffuser element, which is accompanied by a uniform progression of radiation intensity.

[0072] In an advantageous embodiment, the diffuser element has scattering elements embedded in the matrix of the diffuser element, or the matrix of the diffuser element is coated with a material having scattering elements. The scattering elements ensure that light coupled to the diffuser element is scattered or deflected so that it can be radiated laterally from the diffuser element. At least one scattering element is positioned essentially parallel to the entire long axis of a diffuser element having a uniform cross-section, or at one angle to the long axis in the case of a tapered diffuser substrate. The scattering elements may be advantageously positioned tubularly and especially coaxially with respect to the long axis. Multiple scattering elements can be arranged around the long axis of the diffuser substrate in a particular predetermined geometric arrangement, preferably in a regular structure around it, and especially preferably in a ring. Thus, multiple scattering elements positioned at one angle preferably intersect at a single vanishing point outside the diffuser substrate.

[0073] In a preferred modification, the scattering elements are uniformly distributed radially around the long axis of the diffuser substrate, where the core region around the long axis has no scattering elements per unit area or a significantly reduced number of scattering elements per unit area compared to the number of scattering elements per unit area outside the core region, and thus the scattering elements are intended to be mainly located outside this core region in the matrix. This makes it possible to achieve that coupled light, which is usually coupled with a low NA (<0.3, typically about 0.2), is not immediately diffused by the scattering elements. On the other hand, the core region, which has almost no scattering elements, can guide sufficient light to the distal end of the diffuser substrate without scattering. This makes it possible to reduce the intensity near the coupling site (proximal end of the diffuser substrate) on the one hand, and increase the intensity near the distal end of the diffuser substrate on the other hand.

[0074] The diffuser element may be structured at least partially or segmentally in its bulk (Volumen) and / or on its surface, or it may have a colored or colorless, particularly transparent, preferably colored glass or colored plastic, sheath. Surface structures of the diffuser element allow for improved adhesion of the reflector layer and improved scattering properties. An example of a coating or sheath that further assists Lambertian radiation properties, particularly reducing radiation directed forward in the direction of light coupling, is a coating having boron nitride. Further coatings of this type may consist, for example, titanium oxide, calcium carbonate, or zirconium oxide. The additional sheath may be finished, for example, as a flint glass tube containing scattering elements within a glass matrix. However, colorless or colored sheaths are also possible.

[0075] Accordingly, one embodiment is intended in which a diffuser element having a reflector layer is surrounded at least partially or partially by a transparent or translucent, colorless or colored sleeve, in which case the sleeve typically has a diameter corresponding to 1.1 to 1.5 times the diameter of the diffuser element. Preferably, the sleeve is composed of a rigid tubular member of glass or metal and / or a flexible tube, in which case the tubular member and / or tube may preferably further contain a scattering center, and the sleeve is finished at least partially from one or more thin-walled heat-shrink tubing.

[0076] A particularly preferred modification of the diffuser element is proposed in which a diffuser substrate having the aforementioned reflective surface distally is provided with a transparent and / or translucent, colored or colorless sleeve that surrounds it at least partially or intermittently. This allows for mechanical or chemical protection on the one hand, and on the other hand, with a suitable selection of material, especially if it encloses the scattering center, the radiative properties can also be further optimized with respect to the uniformity of the intensity of the lateral radiation. This can, for example, assist Lambertian emission.

[0077] In a preferred modification, the sleeve is finished with at least one thin-walled heat-shrink tubing in sections. This, on the one hand, also achieves additional diffusive scattering, thereby assisting Lambertian radiation. On the other hand, it provides mechanical protection, preventing chipping that may occur, for example, if the diffuser is damaged. For this purpose, for example, a thin-walled heat-shrink tubing made of white PET with a wall thickness of about 5 to 15 microns has been demonstrated as the sleeve. To suppress reflection, thin-walled, black or colored heat-shrink tubing may be partially provided. The coloring can be selected so that the wavelengths used are absorbed particularly well. Such heat-shrink tubing can be further finished to be biocompatible. In this way, injury to people near or in direct contact with the lighting system can be avoided. However, it is also possible that the sleeve may be advantageously constructed as a layer (Schlichte) having polyamide (PA), polyimide (PI), or polymethyl methacrylate (PMMA) or wax, wax-like components, or alkylsilane, or may be made from at least one of these materials.

[0078] The diffuser substrate may include, or consist of, a matrix made of transparent plastic, and especially for improved workability, glass, quartz glass, or transparent glass-ceramic, where the scattering element is • In the case of a plastic matrix, it may contain or consist of porous, colored, or pigmented plastics. • In the case of a glass matrix, it may contain or consist of glass or glass ceramics having pores, particles, porous or colored or heterogeneous properties, or glass ceramic components and microcrystals contained therein. • In the case of a quartz matrix, it contains or consists of pores, porous quartz glass, or ceramic or polycrystalline particles. • In the case of a transparent glass-ceramic matrix, it may contain or consist of glass or glass-ceramic having pores, particles, porous or colored or heterogeneous glass or glass-ceramic components and microcrystals contained therein, or • Combinations of those scattering elements Includes.

[0079] In the case of a glass or glass-ceramic matrix, the heterogeneity of the glass or glass-ceramic forming the scattering elements includes phase separation, segregation and / or particulate inclusions, nuclei and / or microcrystals, and the scattering effect can be controlled as desired by a temperature-time process. Here, the concentration of scattering elements in the scattering region should be 10 ppm to 1000 ppm, and preferably 20 ppm to 100 ppm. Here, the concentration in ppm refers to the ratio of scattering particles to the mass ratio of the components of each material in which the scattering particles are embedded, particularly plastic, glass matrix or quartz matrix. Here, each formed scattering element (meaning, for example, pores, particles, porous or colored or, for example, white, or heterogeneous glass or glass-ceramic components and the microcrystals contained therein) preferably has a diameter of 10 nm to 1000 nm, and particularly preferably 100 nm to 800 nm.

[0080] The diffuser element may contain borosilicate glass, crown phosphate glass, lead silicate glass, zinc silicate glass, or alkali zinc glass, and / or the scattering element may contain a flint glass rod, which is particularly advantageous if it is surrounded by a sleeve tube made of borosilicate glass. This has the advantage that the diffuser substrate as a whole is detectable at least partially or segmentally in radiographs, thereby allowing the location of the diffuser within the patient's body to be identified. For example, with respect to the wavelengths used for EVLT applications of 0.8 μm to about 2.2 μm as mentioned at the beginning, special IR-transmitting glass, such as crown phosphate glass or lead silicate glass, can also be used.

[0081] In approaches based on quartz glass, if the quartz glass has particularly few OH groups, applications in the UV and / or IR range up to about 2.5 μm can be addressed. Herein lies the extremely high heat resistance and very low fundamental absorption of quartz, which enables larger laser power outputs, especially up to 50 W, in the aforementioned applications. In addition to scattering elements made of porous quartz glass, scattering elements made of or containing ceramic pigments, such as titanium dioxide, zirconium oxide, or aluminum oxide, can also be used. Diffuser substrates based on quartz glass can be spliced ​​particularly well to light guides made of quartz fibers, where the quartz fibers consist of a core and a cladding (also called a sheath) with slightly different refractive indices. The cladding can also consist of organic materials, such as fluoroplastics, PMMA, or polyimide.

[0082] A glass-ceramic-based approach for diffuser substrates and / or scattering elements can consist of transparent aluminosilicate-high-temperature quartz mixed crystal glass ceramics. These are extremely thermal shock resistant and have high spectral transmittance down to about 2.5 μm. For example, keytite glass ceramics, which can be manufactured from high-temperature quartz mixed crystal glass ceramics by a suitable tempering process, are suitable as scattering elements. Furthermore, cordierite glass ceramics or magnesium aluminum silicate glass ceramics are suitable as diffuser substrates and / or scattering elements. A particularly preferred diffuser substrate in terms of the manufacturing process is one in which the diffuser substrate consists of light guide rods made of borosilicate glass rods, zinc silicate glass rods, or alkali zinc silicate glass rods, and / or the scattering elements consist of flint glass rods, which are advantageously surrounded by sleeve tubes made of borosilicate glass, zinc silicate glass, or alkali zinc silicate glass to form a preform.

[0083] In a further embodiment of the present invention, both the diffuser substrate and the sleeve tube may be made of the same type of glass. In this case, the refractive index of the sleeve tube is preferably less than or equal to that of the matrix glass, and particularly preferably both refractive indexes are of the same magnitude. This facilitates the extraction of scattered light in the diffuser. This enables a cost-effective process for manufacturing the diffuser, which makes it possible to obtain a diffuser with uniform radiant intensity over substantially any length.

[0084] The present invention relates to a lighting system for medical technology treatment and / or diagnostic systems, particularly for use in biological tissues. At least one light source, A light guide that can be connected to or assigned to the proximal end of the light source, Preferably, an optical element configured as a diffuser element and positioned at the distal end of the light guide, The present invention also relates to a method for manufacturing the system having the following steps: Light from the ride guide can be coupled to the optical element, and the method is as follows: • The step of preparing a diffuser element having an outer surface, The step of covering the outer surface at least partially with a light-reflecting reflective layer having a mirror layer, wherein the optical element has a light-reflecting region covered with the reflective layer and a light-transmitting region without the reflective layer, so that the light emitted from the optical element can be at least partially reflected and the light can be emitted as intended in the light-transmitting region. The reflectance of the reflector layer is greater than 90% for at least one wavelength range.

[0085] Ideally, a lighting system covered with a reflector layer has at least one, preferably more, of the aforementioned properties or features to provide a corresponding advantage. The reflector layer is preferably extended in the axial direction of the optical element, particularly in the longitudinal direction. The outer surface can also be understood as an outer covering layer or base layer region, and its wall thickness is advantageously in the range of 1 to 100 μm.

[0086] The outer surface is pre-treated or activated by a chemical or physical process to modify the surface properties of the outer surface, thereby providing a base layer region having at least one modified surface property, and the outer surface can therefore be understood as an outer layer or base layer region, and it is also advantageous that its wall thickness is in the range of 1 to 100 μm. Accordingly, the reflector layer may be applied directly to the outer surface, which is not pre-treated, or on the outer layer or base layer region.

[0087] The base layer region may include an outer surface layer having at least one modified surface property, in particular an increased surface energy and / or an increased number of oxygen radicals, which ensures good adhesion of subsequent coatings, e.g., an adhesion layer and / or a reflector layer. Such a surface sublayer of the coating can be manufactured or produced, for example, by chemical or physical processes to alter the surface properties of the outer surface or the coating, in particular by plasma treatment (e.g., low-pressure plasma or atmospheric-pressure plasma), UV treatment, arc discharge (corona), and / or chemical treatment, e.g., using alkaline cleaning agents in an ultrasonic bath, or a combination of these methods. Plasma may further remove fat, oil or similar residues and additionally activate oxygen radicals. In other words, the base layer region, or the bottom layer of the base layer region, may be formed by a radial portion including the outer surface of the outer surface. That is, the base layer region may also consist of, for example, a single layer, which is formed by a chemical or physical process based on the outer surface of an optical element with respect to its surface properties.

[0088] However, the base layer region can also consist of a series of layers, where, for example, the bottom layer of the base layer region is formed by a chemical or physical process based on the outer surface of an optical element with respect to its surface properties, and further layers are applied on top of this bottom layer.

[0089] The reflector layer may also be applied to the outer surface by means of cathode sputtering, high-frequency sputtering, reactive sputtering, magnetron sputtering, vapor deposition, especially ion beam deposition and / or thermal deposition. The fabrication of at least one, preferably more than one, layer of the reflector layer may also involve other coating methods besides those described above, such as vacuum methods (e.g., ion beam or thermal deposition) and chemical vapor deposition (CVD, e.g., PECVD, especially PICVD). Further coating methods for providing one or more layers of the reflector layer may also include liquid-phase methods, such as immersion coating or spray coating. In this case, additional functions, such as reduction of the coefficient of friction, can be imparted.

[0090] In this process, the material provided for coating, particularly oxides, nitrides, or oxynitrides of Si, Al, Ti, Zr, Hf, Y, and Zn, can be applied from a so-called sputtered target using, for example, a sputtering process. These materials can exist as a metallic target or a partially ceramic target. The target purity is typically 99% or higher, however, lower purities are also possible. In some cases, a thicker layer may be required.

[0091] An adhesion layer or adhesion promoter layer may be applied to the outer surface, and / or a passivation layer may be applied to the reflector layer, preferably by cathode sputtering, radio frequency sputtering, reactive sputtering, magnetron sputtering, vapor deposition, especially ion beam vapor deposition and / or thermal vapor deposition. In this case, the base layer region may be configured as an adhesion promoter layer. Thus, it may be intended that greater adhesion exists between the base layer region and the reflector layer applied thereon than the adhesion that exists between the treated or untreated outer surface and the reflector layer applied thereon. In other words, the enhanced adhesion may exist between the reflector layer and the layer that may be configured as the uppermost layer of the base layer region below it, which has increased surface energy and / or an increased number of oxygen radicals, or as an adhesion layer applied to the outer surface by coating.

[0092] The base layer region may consist of multiple adhesion layers, where at least one or all of the adhesion layers applied on top of the bottommost adhesion layer have higher adhesion to the adhesion layer below it than to the adhesion layer below that layer if there is an adhesion layer below it. In other words, the outer surface or optical element can be coated with one or more adhesion layers forming the base layer region. For at least one adhesion layer, the use of at least one material from the group of Si, Al, Ti, Zr, Hf, Y, or Zn is intended, advantageously as an oxide, nitride, or oxynitride. However, other materials, such as borides, carbides, or carbonitrides, can also be used. A preferred layer system includes, for example, TiO2.

[0093] The base layer region or the adhering layer and / or passivation layer, especially if it has (one or more) layers applied by coating, can have an amorphous structure, or a crystalline or polycrystalline structure. Typical examples of amorphous coatings include SiO2, Si3N4, Al2O3, and AlSiO2 x Alternatively, BN can be used, and typical examples of crystalline coatings include anatase or rutile TiO2, γ-Al2O3, or crystalline AlN. However, mixed phases of amorphous and crystalline materials can also be formed.

[0094] A more preferred lighting system comprises a mirror layer or reflector layer having different reflection or transmission behavior for different wavelengths, particularly for adjacent wavelengths λ1 and λ2, where the wavelength difference Δλ = |λ1-λ2| < 200 nm, preferably < 100 nm. This enables a lighting system with switchable radiation characteristics, where these different wavelengths λ1 and λ2 can be adjusted via the light source. The fundamental idea is that, for the first wavelength λ1, the lateral reflector layer applied on the sheath is sufficiently transparent, and the reflector layer or mirror layer is designed so that light rays can be transmitted. This allows for the radiation behavior of a randomly radiating diffuser. When switching to the second wavelength λ2, the lateral reflector layer now acts as a mirror, resulting in lateral focusing of radiation directed within the compartment. For these two different wavelengths λ1 and λ2, the mirror layer or reflector layer has, in particular, advantageously at least 10%, and especially preferably at least 30%, different reflectance and / or transmittance. This particularly advantageously allows for a significant change in radiation between the main random radiation and the radiation focused to a single area when switching wavelengths. Therefore, the lateral reflector layer is designed to have a particularly narrow bandwidth with respect to wavelength. In this case, it is advantageous if the distal reflector has high reflectivity for both λ1 and λ2. This is particularly advantageous in medical technology applications of lighting systems. For example, wavelengths λ1 and λ2 that are so close to each other are 980 nm and 1064 nm, which are commonly used in medical technology applications. Such behavior can be achieved, in particular, by the dielectric layer system described above. It should be noted, of course, that λ1 and λ2 may be further apart (>200 nm), but this could result in very different tissue absorption characteristics at such different wavelengths in medical applications. Therefore, the wavelengths cannot be arbitrarily and / or arbitrarily wide apart.

[0095] In this regard, further applications include achieving different penetration widths of light rays using different wavelengths that may be switchable, which can offer advantages from a surgical perspective, particularly in terms of tissue penetration behavior.

[0096] Coating an optical element with a reflective layer involves first activating a base layer region consisting of a single deposited layer and / or an outer surface, or bringing about a series of deposited layers, and then applying a mirror layer (on the base layer region) consisting of a single layer or a series of layers, particularly alternating high-refractive-index and low-refractive-index layers, or a system of layers consisting of high-refractive-index and low-refractive-index layers. The activation of the outer surface can be understood as removing residues and / or bringing about modified surface properties, particularly those with increased surface energy and / or an increased number of oxygen radicals.

[0097] Coating or activation is advantageously carried out at temperatures below 50°C. This relatively low temperature has the particular advantage of allowing the optical element to be coated with a polymer layer acting as a sleeve. Processing in a vacuum, and especially without breaking the vacuum, is also preferred. For example, a base layer region can be first introduced in a vacuum, and then a mirror layer can be applied in the same vacuum. Further passivation layers can then be applied in the same vacuum.

[0098] Preferred applications of the lighting systems described above in various modified forms are, as stated at the beginning, intended for use in photodynamic therapy (PDT) or photoimmunotherapy (PIT) for treating tumors, for example for intravenous laser therapy (EVLT) for treating varicose veins, for example for laser-guided interstitial hyperthermia (LITT), or for use in the fields of dentistry, ophthalmology, and dermatology. In the field of dentistry, applications in the treatment of wounds or periodontal disease are particularly noteworthy. Furthermore, in brain research, there is an application in which light can be used to stimulate individual brain regions, thereby treating the symptoms of disease.

[0099] Further applications of the illumination systems described above in various modified forms are intended for use in photodynamic therapy (PDT) or photoimmunotherapy (PIT) for the treatment of tumors, where at least one light guide with a diffuser element captures light emitted from other diffuser elements and transfers it through the light guide to a detector for spectroscopic analysis. In addition to diffuser light guides that emit various types of light, a diffuser light guide that receives light is also applied to the patient, and the response to PDT treatment can be estimated by the spectral difference between the combined light and the received light (see Finlay et al., Proc. SPIE Int. Soc. Opt. Eng. June 14, 2014; 5315: pp. 132-142). Furthermore, such systems can also be used for dose measurement during PDT or PIT treatment, for example.

[0100] Furthermore, it is advantageous for industrial applications, such as as an element of equipment for industrial applications to illuminate hollow spaces precisely, for example, for inspection of hard-to-reach locations on or within machinery, especially when uniform illumination is important, for light transmission of workpieces with small openings, or even for spectroscopic applications, or for irradiating samples in biochemistry where biochemical in-vitro reactions are stimulated by light, i.e., in the field of in-vitro diagnostics. Applications are also seen in the precise curing of resins or adhesives, or materials containing them, where uniform illumination is essential or where the bonding site is difficult to access.

[0101] The present invention will be described in more detail below with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding elements. [Brief explanation of the drawing]

[0102] [Figure 1] Figure 1 is a schematic diagram of a lighting system for PDT or PIT applications, comprising a light guide and a diffuser element that radiates light locally in one direction. [Figure 2] Figure 2 is a schematic diagram of a diffuser element. [Figure 3] Figure 3 shows a comparison of surfaces with different coatings after abrasion testing. [Figure 4] Figure 4 is a schematic diagram of an example of a reflector layer. [Figure 5] Figure 5 is a schematic diagram of an embodiment having a reflector layer, an adhesion layer, and a passivation layer. [Figure 6] Figure 6 is a schematic diagram of an embodiment having a dielectric reflector layer, an adhesion layer, and a passivation layer. [Figure 7] Figure 7 is a graph showing the wavelength dependence of reflectance over time. [Figure 8] Figure 8 is a graph showing the wavelength dependence of reflectance over time for various angles of incident light. [Figure 9] Figure 9 is a graph showing the wavelength and incident angle dependence of the reflectance for an interference reflector over time. [Modes for carrying out the invention]

[0103] In describing the detailed embodiments below, the same reference numerals in the accompanying drawings indicate the same or the same element having the same function. For better understanding, the following definitions are made: In the sense of this disclosure, the term "lighting system" includes lighting devices and, in particular, lighting devices suitable for use for medical technology purposes and, in particular, insofar as they are to come into contact with living tissue, at least partially disinfectable and / or sterilizable. The notation "medical technology therapeutic and / or diagnostic system" includes, but is not limited to, the suitability, use, or application of the lighting system itself disclosed herein as a medical therapeutic and / or diagnostic system.

[0104] Figure 1 schematically shows the configuration of the illumination system 1 according to the present invention. A medical technology PDT application is shown as an example. In the example shown, the illumination system 1 includes an LED or laser light source 10 that emits light in a specific spectral range when in operation. For PDT or PIT applications, as described at the beginning, a laser is used that emits wavelengths matched to a pre-administered biochemically modified dye (photosensitizer), usually in the visible range, for example, the green spectral range of 532 nm, or for example, the red spectral range of 690 nm.

[0105] The light guide 30 is connected to the laser light source 10 at its proximal end 30.1 by a plug 20 or other connecting or coupling element. In this case, the end of the light guide 30 to which the light is coupled is indicated as the proximal end 30.1. At the distal end 30.2, the light guide 30 has an optical element in the form of a diffuser element 40, which is formed within healthy tissue 50 and thus introduced into or near adjacent tumor tissue 60. In this case, the other end of the light guide 30, which is usually positioned away from the proximal end 30.1 and specifically emits light, is indicated as the distal end 30.2.

[0106] In this process, the laser beam reaches the diffuser element 40 via photocoupling 31 through a light guide 30, and the diffuser element is composed of, for example, a diffuser substrate 41. The light is emitted laterally along the length L of the diffuser element, indicated by the long axis L, or extracted in the light-transmitting region as a light extraction 42. In this process, it is important that the emission is as uniform as possible along the length of the diffuser element 40. In particular, intensity peaks should be avoided. In the example shown, the diffuser element 40 shines into the tumor tissue 60 in only one direction, i.e., regionally. Ideally, the tumor tissue 60 will die after treatment due to the photo-induced biochemical reaction as described at the beginning.

[0107] While not limited to the examples shown here, typically a quartz fiber is used as the light guide 30, where the plug 20 is typically configured as a coaxial plug connector, a so-called SMA plug, and the fiber is advantageously bonded to the plug 20. A plug 20 having a nickel silver sleeve can also be advantageous in terms of thermal loadability, in which case the light guide 30 is introduced / crimped to the nickel silver sleeve by shape bonding, particularly by plastic deformation. Furthermore, for higher laser power, a plug 20 in which the fiber end of the light guide 30 is protected by a conical prism can also be used, which can be advantageous in error correction.

[0108] Figure 2 schematically and illustratively shows the configuration of the diffuser element 40. The diffuser element 40 preferably consists of a diffuser substrate 41 spliced ​​or attached to the light guide 30. In the aforementioned applications, the light guide 30 is usually made of a quartz fiber with a core. In this case, the core has a refractive index n1 and a core diameter of typically 100 μm to 1000 μm, preferably 200 μm to 600 μm, while the sheath or outer surface has a refractive index n2, where n1 > n2. The numerical aperture NA that can usually be achieved is about 0.22 or less, for example, 0.1. Higher NA values ​​up to 0.4 or 0.6 can also be achieved with special doping. The photocoupling 31 from the light guide 30 occurs on the corresponding coupling surface of the diffuser substrate 41.

[0109] Furthermore, in the case of splice connections, it can be advantageous if the coupling between the diffuser substrate 41 and the light guide 30 is performed in two stages. First, only a short section of the light guide 30 (typically several tens of millimeters in length, e.g., about 10-20 mm) is spliced ​​to the diffuser substrate 41, which is then coated, and then the original pigtail, consisting of the light guide 30 and plug 20, is spliced ​​to the short section of the light guide 30. This is particularly advantageous in that the reflector coating is not thermally destroyed or the reflector properties are not altered to an unacceptable degree by the splice process, which induces locally high energy density by the laser and / or corona discharge. Moreover, in the case of a coating process for the diffuser substrate 41 with only a short section of the light guide 30, it can be easily placed in a coating chamber. Thus, the handling complexity can be significantly reduced compared to handling with a complete pigtail.

[0110] The diffuser substrate 41 or optical element includes, for example, a matrix made of a matrix element having embedded scattering elements, and / or a sleeve tube. However, the diffuser substrate 41 may also be made of glass, in which the scattering properties can be adjusted to a target by heat treatment using defined temperature and time control. For the diffuser substrate 41, a glass-ceramic matrix is ​​also conceivable, in which the microcrystalline density and / or microcrystalline size can be adjusted to a target by similar temperature and time treatment, and thus the scattering properties can also be affected. An optical element based on plastic, which is also fitted with polymer optical fibers (POF) as a light guide 30, is also conceivable.

[0111] A sleeve made of plastic, glass, metal, or ceramic material may be provided to avoid stray light from the connection area between the light guide 30 and the diffuser base 41, and also for mechanical stabilization of this connection area.

[0112] The diffuser element 40 has a reflector layer 43, and optionally a reflector or further reflector layer at its distal end 44. This results in three essentially equal contributions to the light extraction 42: extraction of light from the side at a predetermined radiation angle 42.1 42.2, extraction of light from behind through the reflector layer 42.3, and extraction of light from the distal end 42.4.

[0113] Therefore, for medical technology applications where the tissue should be irradiated as intended, the proportion of backlighting 42.3 must be kept as small as possible, which requires the highest possible reflectivity of the reflector layer 43. Furthermore, at the distal end 44, it may be necessary to significantly prevent distal light extraction 42.4, which also necessitates the highest possible reflectivity of the reflector layer at the distal end 44. Moreover, the highest possible reflectivity can increase the efficiency of back reflection and / or lateral light extraction 42.2 at the distal end 44. In both cases, a reflectivity value greater than 90%, preferably greater than 95%, and particularly preferably greater than 99% is required. Furthermore, to prevent excessive heating, the reflector layer should not have large absorptions.

[0114] Corrosion resistance is also important, especially in relation to the complex cleaning process and the mechanical load resulting from friction when, for example, the diffuser element 40 is moved many times within the catheter. Therefore, the layer with the reflective layer can be subjected to a cleaning process (e.g., using ethanol) or pass abrasion tests, such as the eraser test or even the "Tesa test" or tape test.

[0115] Therefore, Figure 3 shows a comparison after the eraser test, with the reflector layer 43, constructed with a four-layer design as the dielectric multilayer system 45, shown at the top of the image. The bottom of the image shows the surface of the metal Cr+Au reflector coating 46 for comparison. It can be seen that the pure metal reflector coating could not withstand the load sufficiently, and that the dielectric multilayer system 45 could be better adapted to the mechanical load.

[0116] Figures 4-6 schematically show typical examples of the reflector layer 43, not shown to scale. Figure 4 shows a simple layer structure for the outer reflector 43, in which a metal mirror layer 43.2 is deposited on a diffuser substrate 41. In this case, the reflected light can be directed at the mirror layer 43.2, the adhesion promoter layer 43.1, or the reflector layer 43 at various incident angles 102 with respect to the perpendicular 47.

[0117] Advantageously, the maximum reflectivity for light incident obliquely on the reflector surface is greater than 50%, preferably greater than 70%, and particularly preferably greater than 90%. Within the scope of this disclosure, obliquely incident light is understood to be light that strikes the reflector layer 43 at an angle between 0° and 90° absolute with respect to the perpendicular 47 of the reflector layer 43, or advantageously greater than 50°, preferably greater than 70°. Since the light is essentially guided and scattered along the diffuser element 41, a certain proportion of the light strikes the reflector layer 43 obliquely. It is therefore advantageous that this portion of the light is also reflected.

[0118] The metallic mirror layer 43.2 can advantageously consist of noble metals, such as Au, Ag, Pd, or Pt, which have high reflectivity in the visible range of light. Alloys of multiple metals, or multilayer metallic layers, are also conceivable. However, in some cases, layers of such simple structure, as shown in Figure 4, may not be practical with respect to mechanical wear, adhesion, or chemical attack.

[0119] Accordingly, Figure 5 shows a more complex multilayer structure having an adhesion layer 43.1 or adhesion promoter layer, the original mirror layer 43.2, and an additional passivation layer 43.3 directly above the diffuser substrate 41. In this case, it should be noted that conventional adhesion promoters for noble metals, such as Cr or Ni, lead to a reduction in reflection by the induction of light through a fiber or optical element. This is true even for an adhesion layer 43.1 with a very thin thickness of, for example, 10 nm. To avoid significantly reducing reflection, a dielectric layer can be used as an alternative adhesion layer 43.1. In this case, oxides, nitrides, or oxynitrides of Si, Al, Si, Al, Ti, Zr, Hf, and optionally further Y and Zn can be used. The thickness of the noble metal layer finished as the mirror layer 43.2 may be in the range of 10 nm to 5000 nm, preferably 10 nm to 300 nm. The thickness of the adhesion layer 43.1 or adhesion promoter layer is typically in the range of several tens of nm, preferably 5 nm to 50 nm.

[0120] Further examples of possible mirror layers 43.2 are base metal layers with high reflectivity, such as Mg, Al, or Cu, embedded in the optical design to enhance reflectivity. In its simplest form, a three-layer design from TiO2(Mg), SiO2, and Mg has been fabricated, where reflectivity can be increased by using a first layer with a high refractive index, a second layer with a low refractive index, and a highly reflective metal layer, thereby increasing the reflectivity of the metal layer. Additional layers, particularly a passivation layer 43.3 following the metal layer, ensure additional protection against corrosion. This additional barrier / passivation layer may contain oxides, nitrides, or oxynitrides of Si, AlSi, Al, Ti, Zr, Hf, and optionally Y and Zn. Since the optical data of the layer is irrelevant at this stage, a corrosive sacrificial metal layer may also be used instead of a functional metal layer. This could be, for example, Al, Cu, Cr, or Ni. However, other metals are also conceivable.

[0121] Without being limited to the illustrative and presented values, the following Example 1 shows the three layer thicknesses of the functional reflector layer 43 within the following range: I. TiO2 (as the attached layer 43.1): Range: 30 nm to 5000 nm, preferably 30 nm to 300 nm, typically 100 nm to 200 nm. II. SiO2: Range: 40 nm to 5000 nm, preferably 40 nm to 380 nm, typically 150 nm to 250 nm. III. Mg: Range: 20nm to 2000nm, preferably 20nm to 200nm, typically 50 to 150nm. IV. SiO2: Range: 5nm to 5000nm, preferably 5nm to 500nm, typically 100 to 250nm.

[0122] The design described above allows for reflection in the wavelength range above 1000 nm to be increased to above 90%, preferably above 92%, or advantageously above 95%, particularly in the case of light incidence perpendicular to the reflector layer 43. Furthermore, the layer system is characterized by maintaining high reflectivity in the angular range of 0 to ±80° measured with respect to the perpendicular to the reflector layer 43, which is essential for applications targeted in the medical field, particularly in the case of tissue irradiation. In the sense of the present invention, high reflectivity is understood as reflection exceeding 50%, preferably above 70%, and preferably above 90% in the aforementioned angular range for maximum reflectivity in the case of perpendicular light incidence.

[0123] The essential advantage of the Mg-based layer in Example 1, similar to that of Cu or Al, is its high reflectivity as a non-metallic coating. A major advantage of this variant is its ease of manufacture. Since only a few layers are required, it can be manufactured in large-scale / in-line facilities. Furthermore, in this case, there are no significant requirements for homogeneity. In addition, the TiO2 and SiO2 layers can be well controlled as standard processes. Similarly, the Mg layer is easily manufactured as a metallic layer. Further advantages over softer noble metal layers are good adhesion and mechanical resistance. As shown in Figure 3, the applied layer can be subjected to cleaning processes (e.g., with ethanol) or even pass abrasion tests.

[0124] In Figure 6, similarly to Figures 4 and 5, a further example of the form of an interference optical dielectric system is shown. In this case, the mirror layer 43.2 is composed of alternating high-refractive-index and low-refractive-index layers, so that high reflection from the transparent dielectric layer can be achieved according to the Fresnel relationship. This is achieved by adjusting the layer thickness by a quarter wavelength with respect to the reference wavelength. As materials for this approach, TiO2, Ta2O5, Nb2O5, or ZrO2, or layers generally having a refractive index greater than 2.2, are considered as the high-refractive-index layer. The above materials can be further stabilized by doping with Al, Si, Y, or Zn, for example. As the low-refractive-index layer, SiO2 or modified forms of doped SiO2 are particularly considered. Oxides, nitrides, fluorides (e.g., MgF2) or oxynitrides of other metals are also possible. SiO2 with low N2 doping is also conceivable and advantageously satisfies the requirement of a low refractive index of less than 1.5 very well. For example, using such a design of a high- and low-refractive-index layer system from 11 layers, a broadband and highly reflective reflector layer 43 or mirror layer 43.2 can be achieved, where, especially in the wavelength range of 1000 nm to 1100 nm, the layer thickness is, for example, 120 nm to 130 nm for TiO2 and 210 nm to 220 nm for SiO2. Due to its broadband nature, for a defined reference wavelength (for example, 1064 nm in this case), reflection is possible over a wide range of incident angles.

[0125] Figure 7 shows the wavelength dependence of reflectance 101, or reflectance, for the multilayer system from TiO2 / SiO2 / Mg / SiO2 described in Example 1, in the progress graph 100. In such a system, the reflectance is particularly high at wavelengths around 600 nm and in the wavelength range of approximately 900 nm to 1100 nm, for example, exceeding 90%.

[0126] Figure 8 shows a graph 100 of further progress for the layer system shown in Figure 7, and the wavelength dependence of reflectance 101, or reflectance, for various incident angles 102. The first progress 100.1 shows the progress for an incident angle of 0° relative to the perpendicular. The second progress 100.2 is measured for an incident angle of 60° relative to the perpendicular, and the third progress 100.3 is measured for an incident angle of 80° relative to the perpendicular. Here, it can be seen that a nearly angle-independent reflectance of 95% can be achieved, for example, in the range of 1000nm to 1100nm. In the example shown, such a layer system was optimized for the wavelength used, 1064nm. By changing the individual layer thicknesses of the mirror layer 34.2, such a high, nearly angle-independent coating can be tuned over a wide wavelength range.

[0127] Figure 9 shows the reflectance 101 (normalized to 100% for the maximum value here) for different incident angles 102 in graph 100 of further progress, particularly for the design of 11 high and low refractive index layers made of TiO2 / SiO2, at various progress points 100.1, 100.2, and 100.3. With respect to the perpendicular to the mirror layer 43.2, the first progress point 100.1 shows an incident angle 102 of 0°, the second progress point 100.2 shows an incident angle 102 of 60°, and the third progress point 100.3 shows an incident angle 102 of 80°. Here, the center wavelength is 1040 nm to 1060 nm.

[0128] Using such layer variations, a highly reflective design can be achieved depending on the absorption or cloudiness of the layers used. Absorption depends on the materials and manufacturing process used, while cloudiness may be caused by the cleanliness of the substrate, defects in the coating process, plasma polymerization, crack formation, or similar factors. Since the coating process must be highly reproducible and stable, PVD-based processes, such as vapor deposition or sputtering, such as magnetron sputtering or ion beam sputtering, are preferably used to produce the reflector layer 43, the adhesion layer 43.1, and / or the passivation layer 43.3.

[0129] The coating process can be represented, for example, by a magnetron sputtering process. In this case, the process, for a 3 or 4-layer system, includes the following steps: • A step in which the surface of the substrate, or the outer surface or surface of the optical element, is cleaned by an ultrasonic cleaning process. • A step of improving adhesion by heat-treating the outer surface or surface of an optical element in a vacuum, through dehydration of the surface. • Reactive magnetron sputtering of metal targets with TiO2 and SiO2 layers, or sputtering of ceramic targets in the case of TiO2, or metal sputtering of Mg. For example, a defect-free sputtering stage using vertical equipment and substrate arrangement, or the arrangement of optical elements.

[0130] Further stages, particularly additional process stages, can be performed using oxygen plasma pretreatment in a vacuum. This helps improve adhesion by preconditioning the surface. However, plasma pretreatment under atmospheric pressure is also advantageous.

[0131] In the case of a metal layer as a reflective layer, it is conceivable that this layer would first be applied to the diffuser material preform and then stretched during the diffuser drawing process. [Explanation of symbols]

[0132] 1. Lighting System 10 Laser light source 20 plugs 30 Light Guide 30.1 Proximal end of the light guide 30.2 Distal end of light guide 31 Optical coupling 40 diffuser elements 41 Diffuser base 42 Light extraction in the light transmission region 42.1 Radiation angle 42.2 Extraction of light from the side 42.3 Extracting light from the rear 42.4 Extraction of light from the distal 43 Reflector layer (light reflective area) 43.1 Adhesion layer 43.2 Mirror layer 43.3 Passivation layer 44 Distal end of reflector 45 Dielectric Multilayer Systems 46 Metallic Reflective Coating 47 Perpendicular line 50 organizations 60 Tumor tissue Graph showing progress over 100 points 100.1 First progress 100.2 Second progress 100.3 Third progress 101 Reflectance 102 Angle of incidence 103 wavelength L long axis

Claims

1. A lighting system (1), in particular a lighting system (1) for a medical-technical treatment and / or diagnostic system, comprising at least one light source (10), a light guide (30) connectable or assignable to the proximal end of the light source (10), and an optical element preferably configured as a diffuser element (40) and arranged at the distal end of the light guide (30), wherein light from the light guide (30) can be coupled into the optical element, the optical element having an outer surface at least partially covered by at least one reflector layer (43), the reflector layer (43) preferably having a mirror layer (43.2), the optical element (40) having a light-reflecting region covered by the reflector layer (43) and preferably a light-transmitting region without the reflector layer (43), such that light coupled into the optical element can be at least partially reflected in the light-reflecting region and light can be emitted in the light-transmitting region, the reflectivity (101) of the reflector layer (43) being greater than 90% for at least one wavelength range, said lighting system (1).

2. The lighting system (1) according to claim 1, characterized in that light can be emitted laterally in a direction transverse to the longitudinal axis (L) of the optical element and over the effective length of the optical element.

3. The lighting system (1) according to claim 1, characterized in that, when light is incident perpendicularly on the reflector layer (43), the maximum reflectivity (101) is greater than 95%, particularly preferably greater than 99%, and the reflectivity (101) is adjustable as desired at a defined wavelength (103) of the light used or within a predefined range around the main wavelength (103) of the light.

4. The lighting system (1) according to claim 1, characterized in that, for an angle of incidence of light greater than 45°, preferably greater than 60°, particularly preferably greater than 80° with respect to the perpendicular to the reflector layer (43), the reflectivity (101) of the reflector layer (43) is greater than 50%, preferably greater than 70%, most preferably greater than 90% of the reflectivity for perpendicular light incidence.

5. At least one region of the diffuser element (40) not covered by the reflector layer (43) extends along the major axis direction of the diffuser element (40), and since this uncovered region is light-transmissive, light guided through the diffuser element (40) can be emitted in a band shape. The lighting system (1) according to claim 1, characterized in that.

6. The mirror layer (43.2) has a metal layer or is composed of a metal layer. Advantageously, the metal layer contains one or more metals from the group of noble metals or one metal from the group of Mg, Al, Cu. The lighting system (1) according to claim 1, characterized in that.

7. The reflector layer (43) has, in addition to the mirror layer (43.2), a lower layer (43.1) below the mirror layer (43.2) and / or an upper layer (43.3) above the mirror layer (43.2). The lower layer (43.1) consists of, in particular, one or more layers, and the upper layer (43.3) consists of, in particular, one or more layers, and The lower layer (43.1) below the mirror layer (43.2) is advantageously configured as an adhesion layer or an adhesion promoter layer, and / or The lower layer (43.1) below the mirror layer (43.2) is advantageously configured as a layer region having surface characteristics chemically and / or physically modified on the diffuser substrate (41), and / or The lower layer (43.1) below the mirror layer (43.2) is advantageously configured as a base layer region consisting of a single layer or a series of layers, The base layer region below the mirror layer (43.2) advantageously includes one or more layers applied to the optical element, and / or in particular includes a surface layer of the optical element having modified surface characteristics manufactured or manufacturable using a chemical process and / or a physical process for modifying at least one surface characteristic of the optical element. The lighting system (1) according to claim 1, characterized in that...

8. The lighting system (1) has at least one of the following features: - The lower layer (43.1), in particular the adhesion layer or adhesion promoter layer (43.1) or base layer region, is configured as a dielectric layer, and the dielectric layer preferably has an oxide, nitride or oxynitride of at least one element from the group of Si, Al, Ti, Zr, Hf, Y, Zn. - The upper layer (43.2), in particular the passivation layer (43.3), is configured as a dielectric layer, and the dielectric layer preferably has an oxide, nitride or oxynitride of at least one element from the group of Si, Al, Ti, Zr, Hf, Y, Zn. The lighting system (1) according to claim 7, characterized in that it has...

9. The lighting system (1) according to claim 1, characterized in that the mirror layer (43.2) or the reflector layer (43) is configured in particular as a dielectric multilayer system having a series of metal oxides and / or metal nitrides with low and high refractive indices.

10. The mirror layer (43.2) or the reflector layer (43) contains scattering centers or a layer having scattering centers, and light can be diffusely reflected at the scattering centers, and The mirror layer (43.2) or the reflector layer (43) preferably further contains at least one layer having a metal or a compound having a metal, for example a dielectric layer, and light can be specularly reflected at the at least one layer having a metal or a compound having a metal, and The lighting system (1) according to claim 1, characterized in that the at least one layer having a metal or a compound having a metal is preferably arranged above the layer having scattering centers, in particular such that the layer having scattering centers is at least partially surrounded externally.

11. The layer thicknesses of the layers (43.1, 43.2, 43.3) have at least one of the following features: ・ The thickness of the adhesion layer (43.1) exceeds 5 nm, preferably exceeds 30 nm, and / or is less than 3000 nm, preferably less than 300 nm, preferably less than 150 nm. ・ The thickness of the mirror layer (43.2) exceeds 10 nm, preferably exceeds 20 nm, preferably exceeds 50 nm, and / or is less than 5000 nm, preferably less than 200 nm, preferably less than 100 nm. ・ The thickness of the passivation layer (43.3) exceeds 5 nm, preferably exceeds 100 nm, preferably exceeds 150 nm, and / or is less than 5000 nm, preferably less than 500 nm, preferably less than 250 nm. The lighting system (1) according to claim 1, characterized in that it is defined according to the above.

12. The lighting system (1) according to claim 1, characterized in that the reflector layer (43) is arranged at the distal end (44) of the diffuser element (40) and / or at least partially covers the diffuser element (40).

13. The lighting system (1) according to claim 1, characterized in that the diffuser element (40) has scattering elements embedded in the matrix of the diffuser element (40) and / or the matrix of the diffuser element (40) is coated with a material having scattering elements.

14. The lighting system (1) according to claim 13, characterized in that the diffuser element (40) contains borosilicate glass, phosphate crown glass, lead silicate glass, zinc silicate glass, or alkali zinc glass, and / or the scattering element preferably contains a flint glass rod surrounded by a sleeve tube made of borosilicate glass.

15. The lighting system (1) according to claim 1, characterized in that the diffuser element (40) is structured at least partially or sectionally in its bulk and / or on its surface, or the diffuser element (40) has a colored or colorless, in particular transparent, outer casing, preferably an outer casing made of colored glass or colored plastic.

16. The mirror layer (43.2) or reflector layer (43) preferably has a difference Δλ = |λ 1 −λ 2 | < 200 nm, particularly preferably Δλ = |λ 1 −λ 2 | < 100 nm for two different wavelengths λ 1 and λ 2 and preferably has a reflectivity and / or transmittance that differs by at least 10%, particularly preferably at least 30%, and The light source (10) of the lighting system is preferably set to be adjustable in the emission of different wavelengths λ 1 and λ 2 so that the lighting system (1) is configured to be switchable in its radiation characteristics, characterized in that the lighting system (1) according to claim 1.

17. A lighting system (1) for a medical-technical treatment and / or diagnostic system, in particular for use in living tissue, having at least one light source (10), a light guide (30) connectable or assignable to the proximal end of the light source (10), and an optical element preferably configured as a diffuser element (40) and arranged at the distal end of the light guide (30), and capable of coupling the light from the light guide (30) to the optical element, in the manufacturing method of the lighting system (1), the following steps: - Preparing a diffuser element (40) having an outer surface; ・ Advantageously, at least partially covering the outer surface in sections with a reflector layer (43) that reflects light and has a mirror layer (43.2), wherein the optical element (40) has a light reflection region covered by the reflector layer (43) and a light transmission region without the reflector layer (43), so that light emitted from the optical element can be at least partially reflected and can be emitted as desired through the light transmission region, and the reflectivity (101) of the reflector layer (43) exceeds 90% for at least one wavelength range, said step having, said method.

18. In particular, the method according to claim 17, characterized in that the outer surface is pretreated by using a chemical or physical process for modifying the surface properties of the outer surface to produce a base layer region having at least one modified surface property.

19. In particular, the method according to claim 17, characterized in that the reflector layer (43) is applied onto the outer surface by using vapor deposition, cathode sputtering, high-frequency sputtering, reactive sputtering and / or magnetron sputtering.

20. Advantageously, an adhesion layer (43.1) or an adhesion promoter layer is applied onto the outer surface and / or a passivation layer (43) is applied onto the reflector layer (43) by using vapor deposition, cathode sputtering, high-frequency sputtering, reactive sputtering and / or magnetron sputtering, the method according to claim 17.

21. Connecting a partial piece of a first light guide to the optical element in a first connection step, and then connecting a partial piece of a second, in particular longer, light guide to the partial piece of the first light guide in a second connection step, thereby connecting the optical element to the distal end of the light guide (30), wherein advantageously, between the first connection step and the second connection step, the outer surface is at least partially covered in sections with a reflector layer that reflects light, the method according to claim 17.

22. Use of the lighting system (1) according to any one of claims 1 to 16 as an element of a device for medical treatment methods, in particular for photodynamic therapy (PDT) or photoimmunotherapy (PIT) for treating tumors, for endovenous laser therapy (EVLT) for treating varicose veins, for laser-induced interstitial thermotherapy (LITT), or for uses in the fields of dentistry, ophthalmology and dermatology.

23. Use of the lighting system (1) according to any one of claims 1 to 16 as an element of a device for photodynamic therapy (PDT) for treating tumors, wherein at least one light guide (30) having the diffuser element (40) captures light emitted from other diffuser elements (40) and transfers it via the light guide (30) to a detector for spectral analysis and / or for dosimetry.

24. Use of the lighting system (1) according to any one of claims 1 to 16 as an element of a device for industrial use for illuminating a hollow space as desired or for irradiating a sample in the scope of in-vitro diagnostics.

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