Device for UV disinfection

Abstract

Devices and methods for UV disinfection The present invention relates to devices and methods for UV disinfection, particularly in vivo UV disinfection of human and animal bodies when colonized with multiresistant pathogens (MRPs), such as methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE). The inventive device (100) for UV disinfection comprises a light emitting diode chip (LED chip) (12) configured to emit radiation in the UVC spectral range (the LED chip (12) forming a light emitting diode (LED) (10) having a package (16), the light emitting diode (12), a spectral filter element (14) configured to substantially limit the radiation emitted by the LED chip (12) to wavelengths below 235 nm, and an optical element (18) for directional emission of the radiation emitted by the LED (10). The inventive UV disinfection method comprises the step of irradiating a surface (O) to be disinfected with the inventive device (100).

Description

[Technical field]

[0001] The present invention relates to devices and methods for UV disinfection, particularly in vivo UV disinfection of human and animal bodies when colonized with multiresistant pathogens (MRPs), such as Methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE).

[0002] The pandemic of multi-resistant pathogens (MRPs) is causing an increase in infections and mortality worldwide, especially among intensive care patients. Existing elimination concepts are not entirely successful. Currently, elimination of MRPs is mainly performed by disinfection. However, this has a success rate well below 50%. Moreover, it does not reach a significant part of the body to be disinfected.

[0003] UV disinfection (also called UV sterilization or UV sterilization) of surfaces (skin) or medical instruments is typically carried out with UV mercury lamps or UV LEDs emitting in the wavelength range of 254 nm or 250 nm to 285 nm. This wavelength is chosen based on the fact that the effect of UV radiation (the "germicidal effect") is highest in this wavelength range. This is specifically radiation from the UVC range, which is assigned by definition a wavelength of 100 nm to 280 nm. In UV disinfection, the irradiated radiation causes irreversible damage to the genetic information of bacteria and viruses, resulting in the disruption of their metabolic processes. UVC radiation can also be used in humans (e.g., for disinfection of pathogens, especially MRSA and MRSE), but the problem is that UVC radiation in this wavelength range penetrates deep into the layers of the skin and causes corresponding damage to healthy human tissues.

[0004] Recently published studies have revealed that short-wave radiation, especially with wavelengths below 230 nm, does not penetrate deep into the skin, mucous membranes, and wounds, i.e., does not overcome the skin barrier, due to its high absorption in the upper layers of the skin (B. Ponnaiya et al., Far-UVC light prevents MRSA infection of superficial wounds in vivo, PLOS ONE 2018, 13(2): e0192053). One of the reasons for this is the wavelength dependence of the absorption coefficient of the skin, which increases significantly for wavelengths below 250 nm (M. Bounnano et al.207nm UV Light - A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. I: In Vitro Studies., PLOS ONE 2013, 8(10): e76968). From this, it can be concluded that at a depth of 18 μm from the skin surface, 233nm UV radiation is attenuated approximately 100 times stronger than 254nm UV radiation. The relative intensity at this time is 10 compared to the intensity at the surface. -4 The difference in the harmful effects of different doses of UV radiation at 222nm and 254nm has already been demonstrated in basal cells of mouse skin using cis-syn cyclobutane pyrimidine dimer (CPD) (Saadati S., Study of ultraviolet C light penetration and damage in skin, Columbia Univ / Univ Gothenburg, 2016: https: / / radfys.gu.se / digitalAssets / 1616 / 1616169_study-of-ultraviolet-c-light-penetration-and-damage-in-skin.pdf).

[0005] WO 2019 / 077817 discloses that UV disinfection with radiation in the wavelength range from 190 nm to 230 nm is suitable for producing a disinfecting effect on the target organisms to be disinfected, without damaging animal or human cells in the process. Corresponding devices and methods for sterilization, especially in cases of colonization with Staphylococcus aureus (S. aureus), are proposed. However, the disclosed devices are based on gas discharge lamps or excimer lamps and are therefore not suitable for clinical in vivo disinfection applications due to the complex light induction required for UV radiation. Furthermore, these devices generate a significant amount of thermal radiation. This in turn means that direct in vivo use on the skin of living organisms is only possible to a limited extent.

[0006] However, apart from this, UVC radiation with a wavelength below 230 nm is in principle suitable for killing pathogens, especially MRPs, both internally and superficially, without any risk of side effects. The radiation dose required to kill MRPs is 100 mJ / cm. 2 The time required for disinfection is less than 100 μg / kg. Therefore, in patients with MRSA colonization of the nasal cavity, throat or wounds, disinfection can be achieved without disinfectants. When MRPs, especially gram-negative bacteria and enterococci, colonize body cavities such as the paranasal sinuses, uterus, bladder or intestinal tract, the use of disinfectants is not possible. Antibiotics can only be used therapeutically, not for disinfection. In such cases, localized treatments with a bactericidal effect in situ are desired. However, for this, devices and methods suitable for in vivo UV disinfection in human and animal bodies are required. In particular, the complexity of wavelength induction in the UV range and the impossibility of uniform and large-area local irradiation of three-dimensional tissue structures in the body have so far prevented clinical application. The radiation sources used so far have the further disadvantage that heat is emitted from the radiation source and a minimum distance is required between the skin or tissue surface, thus limiting the applicable range.

[0007] The object of the present invention is to overcome or at least reduce the problems of the prior art and to provide a device and a method for in vivo UV disinfection of the body, in particular of human and animal bodies. An essential object of the present invention is to provide a device which allows decontamination of various surfaces and cavities, in particular of humans (e.g. nasal cavity, throat, wounds), without causing any damage to the corresponding treated tissues (skin, mucous membranes). The object according to the invention is achieved by the independent claims 1, 7 and 11. Preferred further developments form the subject matter of the dependent dependent claims, which depend respectively thereon.

[0008] The present invention relates to a UV disinfection device comprising a light emitting diode chip (LED chip) configured to emit radiation in the UVC spectral range, said LED chip forming the light emitting diode (LED) with its package, a spectral filter element configured to substantially limit the radiation emitted by the LED chip to wavelengths below 235 nm, more preferably below 230 nm, even more preferably below 225 nm, and an optical element for directional emission of the radiation emitted by the LED.

[0009] The LED chip is preferably made of sapphire (Al 2 O 3) or AlN substrate. It emits substantially in the wavelength range of 210 nm to 240 nm. UVLEDs are usually manufactured using the flip-chip method. The contact layer of the LED chip is contacted by a submount provided with metal electrodes. In this case, the generated radiation is emitted through the substrate, i.e. through the bottom surface of the LED chip. Conventionally, the submount with the LED chip is protected from external influences by an encapsulation. The encapsulation forms a package, and this encapsulated component is usually collectively called LED. For directional emission of the radiation emitted by the LED, the package can contain transmissive optical elements such as an exit window, an exit lens, or a beam-shaping element. Since the choice of transmissive materials is severely limited in the UV range, conventionally, high-purity silica glass is used for the optical elements. In particular, the optical elements may form the cap of the package encapsulation. The term emission means a direct emission of light onto the surface to be disinfected, without any further optical elements being involved after this. The term directional means an emission that can be directed especially onto the surface to be disinfected.

[0010] The device according to the invention for UV disinfection can also comprise several LEDs according to the invention, forming a common LED module. Preferably, such an LED module has a housing for accommodating the LEDs. This housing, in turn, can be arranged on a common circuit carrier (PCB - printed circuit board). Like the package, the housing can have optical elements for directional emission of the radiation emitted by the LEDs. In particular, a cover made of silica glass can be used for this. The LED module can contain several LED chips, with or without individual packages. In the broad sense, the arrangement of several LED chips or LEDs in a common housing can also be considered as packaging.

[0011] In particular, applications in clinical settings for patients colonized with MRSA and other MRPs are anticipated. Disinfecting the nasal passages, throat, wounds and other body cavities with UV LED irradiation will prevent infection of the patient and the spread of MRPs. In particular, the invention describes the use of particularly short-wavelength UVC radiation from LEDs to directly irradiate the skin, mucous membranes or wounds of a patient in order to kill microorganisms without causing significant damage. The mode of action of UV disinfection consists in damaging the DNA of microorganisms. Due to the short wavelength of LED light, this results in a virtually complete absorption of this light in the stratum corneum of the skin, without causing damage to the epidermis of the organism below, ensuring the tolerability of the method.

[0012] The device according to the invention is also called a DUV (deep ultraviolet) LED emitter module, and is particularly well suited for in vivo disinfection of the body. Suitable LEDs have a sufficiently high power density per unit area and a broad UV spectrum. These are advantageous because of their high irradiation efficiency and the possibility that the heat emission is not harmful. However, the challenge in designing a DUV LED emitter module is to achieve a sufficiently high power density per unit area in the wavelength range below 235 nm, while at the same time avoiding the emission of longer wavelength UVC and UVB radiation components (i.e. radiation with wavelengths above 235 nm). UVC and UVB radiation components can penetrate to deeper layers of the skin and cause damage to human tissue. In order to achieve efficient disinfection with a short irradiation time, the irradiation power should be selected as high as possible. However, if the power density is too high, tissue damage, especially due to thermal effects, may occur. In this regard, it must be noted that in order to avoid tissue damage due to thermal effects, the self-heating of the LED or LED module, which increases with increasing operating current (and therefore power density), must be limited. Therefore, an optimum must be found between the selected cut-off wavelength (to avoid radiation-induced tissue damage) and the radiation dose required to obtain a sufficient disinfection effect.

[0013] In a study using a filtered Kr-Cl excimer lamp (emission wavelength 222 nm), this wavelength and exposure dose of 50 mJ / cm 2 In addition, initial studies using a frequency-doubled Ar laser (laser emission wavelength 229 nm) on excised skin showed that exposure doses of 300 mJ / cm 2 were achieved without any or minimal tissue damage, and that superficial decontamination was nevertheless observed. 2 It was found that there was no or little damage to tissue up to 1000 nm. Whereas excimer lamps have significant heat emission and associated skin heating that limits their use, UVLEDs are essentially cold emitters that effectively dissipate waste heat away from the skin and are controlled by limiting the power. In this respect, the heat emission of UVLEDs is not lethal. Furthermore, because excimer lamps are designed in a tubular shape, UV irradiation can only be achieved in a limited range for difficult-to-access skin areas or skin areas of any size, but it is also possible to achieve flexible large-area irradiation shapes by using multiple UVLED arrangements.

[0014] Since the emission spectrum of UVLEDs has a finite full width at half maximum (FWHM typically 8-14 nm) and, in some cases, also parasitic luminescence ("defect luminescence") occurs in the longer UV range, care must be taken in DUVLED modules for UV disinfection to ensure that these spectral components are at the lowest possible intensity or can be completely eliminated. For this purpose, the device has a spectral filter element. One way to do this is to integrate an optical short-pass filter (or alternatively, when used as a short-pass filter, a band-pass filter with a corresponding lower band edge) into the package or directly in or on the LED chip. Such an optical short-pass filter can be manufactured, for example, by a stack of UV-transparent dielectric layers. For example, in III-nitride based UVLEDs, such a short-pass filter can be manufactured by a stack of 10 pairs of AlO x / SiO2 Such optical DBRs (Distributed Bragg Reflectors) can be integrated directly on the LED chip during epitaxy. However, the DBR can also be applied to the LED chip, for example by depositing a mirror pair on the backside of the polished sapphire substrate of the LED chip. Another possibility is to integrate the mirror pair into the UVLED package (for example as part of the silica glass capping of the package). Also, when designing a spectral filter element to match the spectral distribution of the LED chip's emission, it is possible to adjust the reflectivity of the sidebands (for example with chirped DBR mirrors) or the width of the stopband (for example with HfO 2 It is also possible to affect the dielectric constant of the material (e.g., other dielectrics).

[0015] For example, AlO x / SiO 2 The reflectance of the DBR can be designed to have a minimum at 233 nm and increase very rapidly at longer UV wavelengths (i.e., these wavelengths are filtered out). Because there is a practical limit to the number of filter layers possible, the shortpass is generally a bandstop filter with a corresponding band edge at the desired stopband wavelength. However, a 10-pair AlO x / SiO 2 Using mirrors, it is already possible to achieve a stop band width of about 60 nm, and such a filter element can be substantially transparent for wavelengths below 233 nm and reflective (i.e. blocking) for wavelengths between 233 nm and about 293 nm. This is sufficient to prevent skin damage, since the typical emission spectrum of DUV LEDs, with a maximum intensity at 233 nm, is substantially limited to wavelengths between 220 nm and 260 nm.

[0016] log 10 The radiation dose required to disinfect E. coli is similarly wavelength-dependent (and also varies by microorganism). For UV disinfection of E. coli, the action spectrum is maximum at 265-270 nm and decreases with shorter wavelengths. 10To reduce this, a dose of 7 mJ / cm2 is required at a wavelength of 265 nm. 2 , while at 230 nm it is 20 mJ / cm 2 A high dose of irradiation is required. Staphylococcus aureus has a slightly lower inactivation constant k than E. coli (E. coli: k = 0.10575 m 2 / J, Staphylococcus aureus: k = 0.07132 m 2 / J, both for surface irradiation at 254 nm, log at 230 nm 10 Reduced to a slightly higher 30mJ / cm 2 (W. Kowalski, "Ultraviolet Germicidal Irradiation Handbook", Springer 2009).

[0017] The maximum power of UVLEDs with maximum intensity at a wavelength of 233 nm is currently about 1.5 mW. This typically reduces the output power by 30% to 50% over 100 hours, and then decreases slightly. That is, the long-term stable power is currently a maximum of about 0.5 mW. However, even with this relatively low power, it is possible to manufacture DUVLED modules that can be used in clinical environments. When this power is irradiated onto an area of ​​1 square centimeter, the power density per unit area is 0.5 mW / cm 2 Therefore, 30 mJ / cm 2To achieve a dose of 1000 nm, a maximum exposure time of 60 seconds, i.e. about 1 minute, is required. This is already a feasible time for clinical UV disinfection. However, improvements in LED technology will make it possible to further significantly reduce the exposure time in the future. Here, it seems realistic to increase the output power by at least one order of magnitude, for example by growing DUVLEDs on bulk AlN. The required exposure time would then be reduced to less than 6 seconds and therefore even clinical applications during surgical procedures would be possible. There are still no known methods that can effectively reduce postoperative wound infections (SSIs, Surgical Side Infections) in the OR environment. Intermediate disinfection treatments are usually not possible, especially in the case of long procedures. Radiation disinfection associated with surgery could be effective in preventing the colonization of surgical patients with pathogens. Surgical disinfection associated with surgery in the OR environment is particularly important when decolonization of MRSA and other MRPs before surgery is not possible or has not been successful.

[0018] Another way to increase the light output of DUV LEDs is to operate them in pulsed mode. By driving them with very short electrical pulses (a few hundred ns to 1 μs), thermal effects within the LED chip can be avoided. This allows the LED to be operated at a higher current or current density, resulting in higher pulse energy. This can be used to increase the maximum average power or improve the deactivation efficiency. Pulsed irradiation can also reduce the irradiation time required by current DUV LEDs compared to uninterrupted continuous operation.

[0019] One of the problems in integrating optical filters with UVLEDs is that the emission from the LEDs occurs over all solid angles. In the case of flip-chip constructed UVLEDs, the UV light is typically emitted into the upper half of space at all solid angles through a UV-transparent substrate (e.g. sapphire). In the case of planar layer structures of spectral filter elements, the cutoff wavelength of the dielectric short-pass filter (or the correspondingly used band-pass filter) changes with the UV incidence angle, since the light rays have to pass through different effective layer thicknesses depending on the incidence angle. Therefore, for optimal filtering, angle-dependent shifts in the cutoff wavelength of the dielectric short-pass or band-pass filter should be avoided.

[0020] Preferably, the shape of the spectral filter element can be adapted to the emission properties of the LED. In particular, this can be achieved by applying the individual mirror layers of the above-mentioned spectral filter element (DBR) to a hemispherical cap (or cover), for example of UV-transparent silica glass or silicone. In this case, the effective layer thickness traversed by the radiation is the same for all spatial directions. Also, if several LEDs are arranged in an array, a semi-cylindrical cap (cover) can be used instead. An angular independence can then be achieved, at least in the axis perpendicular to the direction of the lines of the array.

[0021] Other approaches to angle-independent filters are known from Yi-Jun Jen et al. (Design and Fabrication of Narrow Bandpass Filter with Low Dependence on Incidence, Coatings, 8(7):231 (2018)) and L. Lin et al. (Angle-Robust resonances in cross-shaped aperture arrays, Applied Physics Letters 97, 061109 (2010)).

[0022] L. Lin et al.In

[2013] , a substantially angle-independent bandpass filter was obtained by exciting surface plasmons localized in cross-shaped holes in a 140 nm thick silver film on glass. The cross-shaped holes have a length of about 240 nm and are arranged in two dimensions with a period of 360 nm. However, this design is for a filter in the infrared range (bandpass with wavelengths of about 1000 nm). Preferably, such a design is applied to UV wavelengths to be used as a spectral filter element for the purposes of the present invention. However, the dimensions and period of the cross structures must be designed to be significantly smaller (preferably 3-5 times smaller) for the present purposes. Moreover, instead of silver, other metals with higher plasma frequencies (e.g. aluminum) are preferably used for the manufacture. The corresponding spectral filter element can then be applied, for example, to UV-transparent silica glass or another UV-transparent dielectric material.

[0023] Yi-Jun Jen et al. also discloses a substantially angle-independent bandpass filter. The Fabry-Perot (e with acute accent on e) filter concept (FP filter concept) is based here on the combination of a metal layer and a dielectric as a mirror layer. The FP filter consists of five layers in the order air / Ag (13 nm) / silicone (90 nm) / Ag (10 nm) / silicone (97 nm) / Ag (20 nm) deposited on glass. This layer sequence allows a substantially angle-independent bandpass filter in the infrared range at a wavelength of 900 nm to be realized. Preferably, this design is also applied to UV wavelengths and used as a spectral filter element for the purposes of the present invention. The layer thicknesses must be adapted accordingly, i.e. preferably reduced by a factor of 3-5. Preferably, instead of silver, other metals with a higher plasma frequency (e.g. aluminum) are used for the manufacture. A UV-transparent dielectric (Al2O3 or HfO2, CaF2) can then be applied, for example to a UV-transparent silica glass or another UV-transparent dielectric material.

[0024] Preferably, at least one monitor diode (photodiode) can be integrated into the light emitting diode or device as a detector for monitoring the radiant power irradiated onto the surface to be disinfected, which allows a continuous monitoring of the emitted or radiated power and can be used in particular to detect defects or improper use of the device.

[0025] The spatial emission characteristics of the LEDs are preferably determined by the width, composition, distortion of the band structure of the LED chip, the external geometry of the LED chip, or by reflectors and openings integrated in the package. The corresponding degrees of freedom in the design of UVLEDs and lamps based on them make it possible to adjust the spatial emission characteristics in a defined way. This is particularly useful for applications in vivo irradiation. For example, to minimize the damaging effects of UVC radiation on the skin, on the one hand the wavelength can be made as small as possible and, on the other hand, irradiation can be carried out at angles of incidence smaller than normal incidence on the skin. Lowering the wavelength significantly below 230 nm is problematic due to the associated reduction in radiation power, but the angle of incidence can be influenced by the geometrical degrees of freedom of radiation in the design of LEDs and heat sinks based on them.

[0026] Furthermore, when irradiating a surface, the spatial uniformity of the radiation power is important in order to ensure the effectiveness of the method in the irradiated area. On the other hand, when irradiating a body opening, the emission should be as uniform as possible over the entire solid angle so that the inner surface of the body opening can be completely irradiated. To eradicate pathogens on topologically complex body surfaces, shallow emission angles are required to irradiate under light-shielding structures. The optical element according to the invention is therefore preferably adapted or can be adapted to the respective irradiation situation. For example, it is advantageous for the emission to proceed in the body cavity so that the body cavity is filled by the optical element in a substantially conformal manner, and for the irradiation to proceed through the entire element structure located in the body cavity. Filling in a maximally conformal manner allows a uniform distance to be provided between the irradiated surface and the optical element.

[0027] The spatial emission of UVLEDs and emitters based on them can be individually adapted in many ways. The spatial emission of the LED chip also depends, among other things, on the band structure of the active zone. The width, composition and distortion of the LED chip can affect the band structure (and therefore also the polarization of the UV light). It is always considered that one of these features will determine if it represents a limiting feature of the spatial emission (e.g. beam angle). The external geometry of the UVLED chip, in particular the size of the chip's side faces, determines the angular emission characteristics and can also be adjusted accordingly. Also, reflectors, openings, lenses and / or pottings of different geometric shapes can be integrated into the UVLED package, which influence the emission. For large-area emitters, the flexibility of the UVLED placement and the use of reflectors in the emitter allow a homogenization of the intensity over the irradiated area.

[0028] The spectral filter element preferably takes the form of an intrinsic Bragg reflector within the LED chip, a Bragg reflector applied to the LED chip, or a Bragg reflector integrated into the package. x Ga 1-x N / A y Ga 1-y N layer pairs (x≠y) can be integrated into the epitaxial layer structure of the UVLED. The Bragg reflector applied to the LED chip can be a layer stack applied onto a substrate. The Bragg reflector integrated into the package can be applied to an encapsulating transmissive cap (e.g., a quartz cap). Alternatively, the spectral filter element can be arranged as an external optical component within the package. When multiple UVLEDs are arranged in a common housing, the spectral filter element can be arranged both on the associated transmissive cover (e.g., a quartz cover) and as an external optical component within the housing as well.

[0029] The optical element preferably comprises a lens, a light pipe or an optical fiber. As indicated above, the optical element may be a simple exit window (for example in the form of a quartz cap of the package). In particular for large area irradiation of surfaces, the exit area, i.e. the area through which the emitted radiation passes in transmission, may also include a lens for beam shaping or collimation. This can be integrated, for example, in the quartz cap or cover, or it can be externally mounted in the package or in the housing. A light pipe can be used to introduce the emitted radiation into a body opening that is directly accessible from the outside, such as the pharynx or nasal cavity. Optical fibers can also be used as optical elements to clearly illuminate hard-to-reach areas or openings of the body with the emitted radiation, for example during "minimally invasive" surgical procedures. Silica glass is preferred as material for the optical element.

[0030] The coupling of UV LEDs to light pipes is intended in particular for irradiation of the nasal and pharyngeal cavities. For the most efficient coupling of the light emitted by the UV LEDs, the light pipe should be located as close as possible to the UV LEDs. Butt coupling between the light pipe and the UV LEDs is also possible, preferably assisted by a UV-transparent adhesive material (e.g. Schott DUV 200). For irradiation, one or more LEDs can be used, but it is also possible to use an array of UV LEDs assembled in a common package. In the simplest case, the light pipe can be designed as a waveguide whose inner surface reflects in the UV range (e.g. by coating with aluminum). Preferably, a flexible, i.e. bendable, material is used so that the light pipe can be easily brought to the body opening and easily reach the area to be irradiated in the angled body cavity.

[0031] For filled light pipes, the fill material should be UV transparent, preferably in the wavelength range of 210 nm to 240 nm. Suitable materials for light pipes and other UV transparent elements include silica glass (e.g., Suprasil, Ultrasil, Infrasil), CaF 2 , MgF 2 or sapphire (Al 2 O 3 ) are included. The geometry of the light pipe can be ergonomically adapted to the surrounding environment of the nasal and pharyngeal cavities. The radiation transmission area outside the nose and mouth can be covered with a UV-reflecting layer (e.g. aluminum or Teflon), which prevents UV radiation from escaping to the surroundings. Also, one or more monitor diodes (photodiodes) can be placed in this area to measure or monitor the UV radiation power and its distribution. In order to allow the UV radiation to escape in a targeted manner at the end of the light pipe, scattering centers can be locally integrated into the light pipe. In the case of optical waveguides made of quartz, for example, such light scatterers can be obtained in particular by local roughening of the material surface.

[0032] Similarly, fiber-coupled UV LEDs can be designed that are particularly suitable for application in hard-to-reach locations in the human body (e.g., ear, urethra, bladder, uterus, etc.). The optical fiber can be partially surrounded by a (optionally UV-reflective) non-UV-transparent cladding to prevent UV radiation from escaping to the surroundings in these locations. Furthermore, light from multiple fiber-coupled UV LEDs can be coupled into a common optical fiber to increase the available power. Furthermore, a monitor diode (photodiode) can be integrated here as a detector to allow continuous measurement of the UV radiation power during operation.

[0033] The optical elements are preferably exchangeable. This also has the advantage that the device according to the invention can be adapted to different tasks without the need for an additional radiation source. The device can therefore be used for both large-area irradiation and spot irradiation with the same radiation source. In particular, this also allows switching between external application on the human skin and internal application inside the human body. Another advantage is that the optical elements after treatment can be cleaned and disinfected in a conventional manner. A high availability for the use of the device can be ensured by fast changeover and simple preparation, especially in the case of light pipes and optical fibers. The exchangeability of the optical elements can also be ensured by corresponding couplings. Also optical elements that are only suitable for single use can be used.

[0034] A further aspect of the invention relates to a medical pad for UV disinfection. It comprises a number of devices according to the invention arranged to form an array, the devices being arranged on a flexible or rigid support element. Such a pad can be applied, for example, directly to external skin areas as a kind of dressing and used for widespread UV disinfection of the irradiated area. In the case of a rigid support element, the pad does not conform to the shape of the body, but a flexible support element (for example made of plastic or woven film) can also be used to suitably adapt the shape of the pad. Thus, with a corresponding pad size, for example, legs or arms can be virtually shaped and wrapped by the pad. However, a rigid support element has the advantage that the pad according to the invention can be easily applied.

[0035] The support element preferably comprises flexible or rigid spacer elements configured to provide a distance between the device arranged to form an array when placed on the surface to be disinfected and the surface. The spacer elements now allow the surface to be irradiated with radiation emitted by the device. A constant distance between the surface to be irradiated and the LEDs in the pad can be established by the spacer elements. This means that this distance is not dependent on the user and a precisely determined radiation dose can be irradiated on the surface. Furthermore, contamination of the LEDs can be avoided, since contact with the skin occurs only via the spacer. In particular, this also prevents soiling or contamination of the optical elements.

[0036] The spacer elements are preferably exchangeably connected to the support element. This has the advantage that the spacer elements can be disinfected or sterilized in a conventional manner. This allows parts of the spacer elements that may be contaminated with infectious agents, i.e. in particular those parts of the pad that have come into contact with the skin of the treated person, to be cleaned before the pad is used further. It is also possible that several spacer elements can be used in turn or even disposable. This ensures a high availability of the pad in terms of use.

[0037] At least one monitor diode is preferably integrated in the pad as a detector for monitoring the radiant power irradiated on the surface to be disinfected. The power emitted by the pad can be monitored via a monitor diode (photodiode). By means of a number of monitor diodes distributed on the pad, it is also possible to check whether the brightness of the surface is uniform.

[0038] Preferably, the pad envelope has an inner UV-reflective layer (e.g., aluminum, Teflon) to homogenize the distribution of UV radiation. The outside of the envelope should be non-UV transparent to protect the surroundings from escaping UV radiation.

[0039] A further aspect of the invention relates to a method for in vivo disinfection of human skin, the surface of the skin being irradiated with radiation emitted by a UV LED in the UVC range, the spectrum of the radiation being substantially limited by a spectral filter element to wavelengths below 235 nm, more preferably below 230 nm, even more preferably below 225 nm, the maximum intensity of the emitted radiation of the LED chip being at wavelengths below 235 nm, more preferably below 230 nm, even more preferably below 225 nm.

[0040] The additional features and preferred further developments mentioned for the device apply mutatis mutandis to the method according to the invention.Such a method can also be used for the treatment of chronic wounds, which are a good haven for MRSA and which could not be treated by radiation therapy so far.This is due in particular to the fact that in the case of chronic wounds, tissues react very sensitively to external influences due to the concomitant inflammation of the respective carrier organs (e.g. skin), and for example the additional heat input caused by the treatment (e.g. waste heat from excimer lamp) represents an unacceptable burden for the person being treated.

[0041] In a further aspect of the invention, a UV disinfection method is disclosed, which comprises the step of irradiating the surface to be disinfected with a device according to the invention (or with a pad according to the invention). The additional features and preferred further developments mentioned for the device or pad apply mutatis mutandis to the method according to the invention.

[0042] Further preferred configurations of the invention are revealed by the remaining characteristics set forth in the dependent claims.

[0043] The various embodiments of the invention mentioned in this application can be advantageously combined together, unless stated otherwise in individual cases. [Brief description of the drawings]

[0044] The invention will now be described with reference to the following exemplary embodiments and on the basis of the accompanying drawings, in which:

[0045] [Figure 1] FIG. 1 shows a schematic diagram of a typical layer structure of a III-nitride based UV LED chip on a submount.

[0046] [Diagram 2] Figure 2 shows the reflectance spectrum of an AlOx / SiO2-DBR with 10 mirror layers (left) and the emission spectrum of a typical UV LED with such a spectral filter element (right).

[0047] [Diagram 3] FIG. 3 shows schematic diagrams of various embodiments for the integration of spectral filter elements.

[0048] [Figure 4] FIG. 4 shows schematic diagrams illustrating various embodiments of the device according to the invention.

[0049] [Diagram 5] FIG. 5 shows a schematic diagram of a first embodiment of a pad according to the invention.

[0050] [Figure 6] FIG. 6 shows a schematic diagram of a second embodiment of a pad according to the invention.

[0051] [Figure 7] FIG. 7 shows a schematic diagram of one embodiment for integrating emission angle independent spectral filter elements.

[0052] FIG. 1 is a schematic diagram of a typical layer structure of a III-nitride UV LED chip on a submount. Usually, sapphire (Al 2 O 3 ) or AlN. Both substrate materials are essentially UV transparent, so they are more suitable for use with conventional Al x Ga 1-xThe UV radiation generated by the N quantum dot film can be efficiently coupled through the substrate. x Ga 1-x N quantum film and typical surrounding Al y Ga 1-y The aluminum content in the N quantum barrier, as well as the Al x Ga 1-x The composition of the barrier can be adjusted by the selection of the width of the N quantum films. For emission wavelengths in the range of 210 nm to 240 nm, the aluminum content in the quantum films ranges from x=0.99 to x=0.6, and the composition of the barrier ranges between y=1 to y=0.65. The width of the quantum films conventionally varies from 0.5 nm to 20 nm, and quantum film thicknesses of about 1 nm are typically used. The number of quantum films ranges from N=1 to N=20, with N=3 being typical. Also, to enable light extraction through the substrate, an arbitrary Al content is used. z Ga 1-z The N current spreading layer must be UV transparent. Therefore, Al z Ga 1-z The aluminum content in the N current spreading layer should be selected so that this layer has a band gap larger than the photon energy of the UV radiation, i.e. the composition is preferably in the range z=1 to z=0.65.

[0053] Similarly, the width of the emission spectrum of the UVLED can be influenced by the design of the heterostructure as well as the variations in the material composition and the individual layer thicknesses. The tunability of the emission wavelength of the UVLED makes it possible to optimally adapt the emission spectrum of the UVLED to the respective application. Thus, according to the invention, for example, the best possible compromise can be established between the emission power of the UVLED, the disinfection effect achieved and the avoidance of damage to the irradiated tissue. As the wavelength becomes shorter, the power and efficiency of the UVLED usually decreases as well, i.e. the disinfection effect becomes lower or the irradiation time has to be increased to achieve the same dose. However, at shorter wavelengths, the UV radiation does not penetrate deeply into the tissue surface, i.e. there is little damage. The power and efficiency of the UVLED increase significantly with increasing wavelength, i.e. the disinfection effect becomes higher. However, at longer UV wavelengths, the UV radiation penetrates deeper into the tissue surface, which means that the damage is greater. In addition, the typical emission spectrum of UVLEDs also contains longer wavelength components (especially wavelength components in the range above 240 nm, which can penetrate to deeper skin layers) that can have a damaging effect on the irradiated tissue.

[0054] FIG. 2 shows an AlO x / SiO 2 The reflectance spectrum of a -DBR (left) and the emission spectrum of a typical UV LED with such a spectral filter element (right) are shown.

[0055] The reflection spectrum shown in the left figure was calculated using the transfer matrix method for normal incidence. The spectral filter element is made of 10 pairs of AlO x / SiO 2 The refractive index and thickness corresponding to the uniform layer were assumed to be: AlO x n=1.85 and d=35.16 nm and SiO 2 n = 1.46 and d = 44.52 nm. AlO x / SiO 2-The reflectance of the DBR is minimal at 233 nm (R=0.7%) and increases very rapidly at longer UV wavelengths (i.e. these wavelengths are filtered out). At a wavelength of 240 nm the reflectance is already R=82%, and at a wavelength of 250 nm it is R=97%.

[0056] The slope of the stop band (DBR) can be adjusted by the number of mirror pairs; that is, the more mirror pairs used, the steeper the stop band will be. Furthermore, the width of the stop band (DBR) can be controlled by the selection of the individual dielectrics. The larger the difference in the refractive index of the dielectrics, the wider the stop band (DBR).

[0057] The figure on the right shows the emission spectrum of a typical UV LED in logarithmic form, with and without the above mentioned spectral filter. For an unfiltered UV LED (dashed line), the peak wavelength in this example is 231.8 nm, with a half-width of 11.9 nm. By integrating a filter element as shown above, it is possible to significantly reduce the longer wavelength UV components of the emission spectrum, without a noticeable reduction in the spectral power in the short-wavelength UV range. The peak wavelength (continuous curve) of the filtered UV LED is slightly shifted to 232.2 nm, and the half-width is significantly reduced to 7.7 nm. In particular, the longer wavelength UV components (wavelengths above 240 nm) are significantly reduced.

[0058] The width of the UV LED emission spectrum can also be affected by heterostructure design and variations in material composition and individual layer thickness.

[0059] FIG. 3 shows schematic diagrams of various embodiments for integrating the spectral filter element 14.

[0060] FIG. a) shows a typical structure of a UVLED chip 12 on a submount 36. The active layer 32 of the LED chip 12 is electrically connected to the submount 36 via contacts 34. The connection is typically realized using the flip-chip method. That is, the substrate 30 of the LED chip 12 on which the corresponding semiconductor layer structure is grown is located above the active layer 32 and emits through this bottom side for radiation decoupling. In the embodiment shown for the integration of the spectral filter element 14, the latter was applied to the free top side of the substrate 30. The spectral filter element 14 and the active layer 32 thus face each other on different sides of the substrate 30. Alternatively, the spectral filter element 14 may be arranged on the side of the active layer 32, i.e. in or adjacent to the active layer 32.

[0061] FIG. b) shows the above-mentioned LED chip 12 with a package 16 on a submount 36 (without application of a spectral filter element). The package 16 protects the LED chip 12 from contamination and damage. The top of the package may be provided with a cap that is transparent to UV radiation (e.g. an exit window made of silica glass). The spectral filter element 14 may be applied to this cap. This corresponds to the application to the substrate 30 according to FIG. a). In the illustrated figure, the cap is also intended to serve for directional emission of the emitted radiation. The cap is therefore at the same time an optical element 18 according to the invention. The illustrated device 100 according to the invention can therefore be used directly for local UV disinfection.

[0062] In Fig. c), several UV LEDs 10 (or LED chips 12) are connected to form a module. In this context, the LED 10 can be understood as an LED chip 12 with a package 16, which does not require a spectral filter element 14 or an optical element 18 according to the invention (the covering of the individual packages here merely represents the internal configuration and does not serve for light emission purposes). The individual LEDs 10 may be arranged on a common circuit carrier 42 (e.g. PCB - printed circuit board) in a housing 40. As in the package of Fig. b), the housing 40 may have a cover that is transparent to UV radiation (e.g. an exit window made of silica glass). If the light emission occurs directly through the cover, this is the optical element 18 according to the invention. A spectral filter element 14 can be applied to the cover. The described module therefore merely represents a multi-LED package, the underlying principle being the same as in Fig. b). This embodiment is therefore merely an extension of a package with several LEDs 10 or LED chips 12.

[0063] Concerning the spectral filter element, it should be noted that the FWHM half-maximum of the emission spectrum of UVLEDs generally ranges from 5 nm to 25 nm, typically from 10 to 12 nm. The integrated emission power from 210 nm to 235 nm is just under 300 μW, and the total power at all wavelengths is about 475 μW. To avoid tissue damage by deeply penetrating UV light, longer wavelength components (above 235 nm) should be excluded from the spectrum as much as possible. As mentioned above, this can be done in particular by integrating the spectral filter element into the module as an optical short-pass filter (short-pass filter with respect to wavelength) or directly into the UVLED chip (for example on the free substrate side) or into the package. However, the spectral filter element can also be integrated into the LED module as an additional element. Such an optical short-pass filter can be obtained, for example, as a DBR (distributed Bragg reflector) using a layer stack of UV-transmitting layers with different refractive indices. For this purpose, in particular, a number of Al xGa 1-x N / A y Ga 1-y N layer pairs (x ≠ y) can be integrated into the epitaxial layer structure of a UVLED. Furthermore, layer pairs of dielectrics with different refractive indices can be integrated on the backside of the substrate or on the package (e.g. on a quartz cap). Other dielectrics suitable for the fabrication of DBR filters include, for example, HfO 2 , Ta 2 O 5 , CaF 2 , MgF 2 , Ga 2 O 3 or AlN. The spectral characteristics of the shortpass filter can be optimized for each application, particularly by choosing the appropriate materials and thicknesses and number of DBR mirror layers.

[0064] FIG. 4 shows a schematic diagram of various embodiments of a device 100 according to the invention. All embodiments can optionally include one or more monitor diodes 52 for monitoring the radiated power. The basic idea behind these embodiments is to adapt the light emission as optimally as possible to the area to be disinfected by a specific design of the optical element 18 according to the invention. In particular, a body-compatible light pipe 50 and an optical fiber 54 are used for this purpose. This diagram should not be interpreted as limiting with respect to the use of individual emitters. For example, instead of the combination of LED 10 and spectral filter element 14 shown, any of the embodiments shown in FIG. 3 may be used with the spectral filter element 14 integrated.

[0065] Figure a) shows an exemplary diagram of a UV disinfection device 100 for application in the nasal cavity. The optical element 18 according to the invention comprises a light pipe 50. The light pipe 50 is configured to direct the radiation generated by the UV LED 10 and filtered by the spectral filter element 14 in a targeted manner into the nasal cavity of the person to be treated. In particular, the light pipe 50 can be a silica glass rod in the form of a waveguide or a solid silica glass rod. The light pipe 50 may also comprise a UV-transparent filling material. Preferably, the shape of the light pipe 50 is adapted to the size and shape of the body opening to be treated (in this case the nasal cavity). In the case of the nasal cavity, this corresponds to a straight section for insertion into the nostril and a spherical shape inclined relative to the straight section in order to fill the nasal cavity. In order to achieve only a localized irradiation of the nasal cavity, the exit area of ​​the radiation can be limited. Furthermore, the light pipe 50 is advantageously replaceable by other light pipes 50 of different sizes and shapes. This allows optimal adaptation of the irradiation to a specific user.

[0066] Figure b) shows an exemplary view of a UV disinfection device 100 for application to the pharyngeal cavity. This view largely corresponds to that shown in a), and the reference numbers apply mutatis mutandis. In contrast to view a), however, the shape of the light pipe 50 is different, in particular the configuration in plan view (straight section immediately adjacent to the balloon-shaped section) and in side view (straight section immediately adjacent to the spatula-shaped section), which corresponds to the structure of the typical human pharyngeal cavity. Here too, it is advantageous to be able to adapt the size and shape of the light pipe 50 by exchanging it.

[0067] Fig. c) shows an exemplary diagram of a UV disinfection device 100 for application in hard-to-reach places and narrow ducts. This diagram also largely corresponds to that shown in a) and the reference numbers apply mutatis mutandis. However, in contrast to the diagram in a), the optical element 18 is not a light pipe 50 but a UV-transparent optical fiber 54 (for example made of silica glass). Such a fiber has the advantage that it is flexible and can be bent. Thus, the fiber can be inserted in places that are otherwise difficult to access (such as body cavities that are not usually open to the outside). In this case, the tip of the fiber can have a shape that is favorable for irradiation, for example a flat, spherical or pointed shape. To prevent UV radiation from escaping the fiber too early in the feed line, a cladding 56 that is opaque to UV radiation may be provided around the part of the fiber facing the LED 10.

[0068] FIG. 5 shows a schematic diagram of a first embodiment of a pad 200 according to the invention, comprising a plurality of devices 100 according to the invention arranged to form an array. The devices 100 are arranged on a flexible or rigid support element 110. In particular, the support element 110 can be flexible (e.g. a woven fabric). In the case of a woven fabric, the individual devices 100 may be electrically contacted by means of woven flexible feed lines. The support element 110 may comprise flexible or rigid spacer elements 112. The flexible or rigid spacer elements 112 are configured to provide a distance A between the devices 100 arranged to form an array and the surface O to be disinfected when placed on the surface O. The spacer elements 112 allow irradiation of the surface O with radiation emitted by the devices 100. The spacer elements 112 may be exchangeably connected to the support element 110, in particular for hygiene reasons. Furthermore, at least one monitor diode 114 may be integrated in the pad 200 as a detector for monitoring the radiation power irradiated on the surface O to be disinfected.

[0069] Figure 6 shows a schematic view of a second embodiment of a pad 200 according to the invention. This view largely corresponds to that shown in figure 5, the reference numbers being applied mutatis mutandis. In contrast to the view of figure 5, however, a side view of a pad 200 according to the invention with a number of additional reflectors 116 is shown here. In particular, this pad may be a pad with a rigid support element 110 (for example a (plastic) frame). Here, by way of example, the spacer element 112 is shown with a curved bearing surface, which allows, for example, to rest directly on a corresponding curved surface. However, any free configuration of the bearing surfaces of the reflectors 116 and the spacer element 112 can also be implemented with a flexible support element 110.

[0070] Fig. 7 shows a schematic diagram of an embodiment for integrating an emission angle independent spectral filter element. The diagram largely corresponds to that shown in Fig. 3b) and the reference numbers apply mutatis mutandis. In contrast to the diagram in Fig. 3b), however, the shape of the transmissive cap used as optical element 18 is different. In particular, the transmissive cap here is dome-shaped and is located on the package 16. In the diagram shown, the cap is at the same time the optical element 18 according to the invention. However, the cap may alternatively be an internal optical element (window or lens) of the device according to the invention.

[0071] The cap may preferably take the form of a hemisphere, for example made of UV-transparent silica glass or silicone. Individual layers of the spectral filter element 14 may be applied directly to the curved surface of the cap. This ensures that the UV light rays from the LED chip 12 are approximately perpendicular to the DBR mirror layer, and the cut-off wavelength of the spectral filter element 14 does not change with the emission angle. Such a configuration has the additional advantage of improving the light extraction from the UV LED, thus increasing the efficiency and output power. A uniform coating of the hemispherical cap may be achieved, inter alia, by a suitable holder in the coating equipment or by rotating the cap during the coating process.

[0072] If several UV LEDs 10 (or LED chips 12) corresponding to FIG. 3c) are connected together to form one module, the spectral filter element 14 can also be applied to a cap (or cover) configured in a semi-cylindrical shape, for example of UV-transparent silica glass or silicone. The diagram shown in FIG. 7 then shows that a layer of a series of spectral filter elements 14 is stretched over the plane represented in the diagram, remaining unchanged over this depth. A disadvantage of such a cylindrical arrangement is that a part of the emitted UV radiation continues to impinge obliquely on the spectral filter element. However, the advantage is that LED line arrays can also be equipped with spectral filter elements 14 adapted to their emission characteristics, and that a homogeneous coating of the semi-cylinder with a dielectric can be performed relatively easily (for example by rotating the semi-cylinder during coating).

[0073] Additionally, we present additional radiation and dose-dependent investigation results for UV disinfection on excised skin samples below.

[0074] The study was carried out using a frequency-doubled argon-ion laser (LEXEL laser, 95-SHG) with a wavelength of 229 nm. For this purpose, human skin excisions were prepared after scar removal. The samples were freshly taken the day before the experiment was performed. 0.2 mW / cm 2 The skin was irradiated with 5000 x 1000 x 1000 for 5 and 30 min. The power was measured using a power meter. The corresponding radiation dose was 60 mJ / cm 2 and 300 mJ / cm 2 Furthermore, 300 mJ / cm 2 At 1mW / cm 2 The cells were exposed to UVB radiation at 1000 dl for 5 min. The same dose of UVB radiation was used as a positive control. Unirradiated samples served as negative controls.

[0075] One 4 mm punch was taken from each sample and transferred to an embedding cassette. The tissue was fixed using a 4% formaldehyde solution. The samples were brought to the laboratory and analyzed on the same day. Paraffin sections (1-2 μm thick) were prepared from the fixed tissue samples and stained with hematoxylin and eosin to allow identification of different tissue structures. Typical DNA damage caused by UV radiation, known as cyclobutane-pyrimidine dimers (CPDs) and 6-4 type photoproducts (6-4PP), were then detected using appropriate antibodies. CPDs account for approximately 70-80% of UV-induced DNA damage, with the remainder being 6-4PP and their isomers or Dewar type photoproducts. DNA modifications caused by both UVC and UVB irradiation should be prevented, especially in the basement membrane. The significant staining of the positive control compared to the actual samples clearly demonstrated that 229 nm radiation, unlike UVB radiation, does not produce any or very few CPDs in cells. Expanded, 300mJ / cm 2 "CPD cells" can be confirmed in the upper part of the epidermis at 300mJ / cm for the second time. 2 No such cells were observed with UVB irradiation. In contrast, CPD damage was very clear and concentrated up to the upper dermis with UVB irradiation. Furthermore, no 6-4PP damage was observed with 229 nm UV irradiation regardless of the radiation dose. In contrast, such damage was very prominent with UVB irradiation.

[0076] Thus, these studies demonstrated that UV irradiation at 229 nm caused little or no DNA damage to excised skin samples, with 300 mJ / cm 2 They succeeded in demonstrating that even such a high dose only causes very superficial damage to the epidermis of a living organism.

[0077] Additionally, a microbial reduction study was performed on pig ears. Marked areas of pig ears were compared with the following disinfectant exposures: - Ethanol-based skin disinfectant (AHD 2000), exposure time 1 minute. - UVC 60mJ / cm 2 , (0.2mW / cm 2 , 5 minutes), - UVC 300mJ / cm 2 , (0.2 mW / cm 2 ,half an hour), - UVC 300mJ / cm 2 , (1mW / cm 2 , 2.5 min) and - Untreated control.

[0078] In untreated controls, colony formation density was low, with only 15 colony-forming units detectable per 1 ml sample volume. All disinfection treatment modes completely eliminated the skin flora without obvious tissue damage, demonstrating the bactericidal effect of the intended radiation range. [Explanation of symbols]

[0079] 10 LED 12 LED chips 14 Spectral filter element 16 Packages 18 Optical Elements 30 Substrate 32 Active layer 34 Contact 36 Sub-mound 40 Housing 42 Circuit carrier 50 Light Pipe 52 Monitor Diode 54 Glass Fiber 56 Clad 100 devices 110 Supporting elements 112 Spacer element 114 Monitor Diode 116 Reflector 200 pads A Distance O surface

Claims

1. A device for UV disinfection, especially of the skin, mucous membranes, wounds, body cavities and surgically exposed tissues and organs, comprising: Light emitting diode chips (LED chips), A spectral filter element, and An optical element is provided, the LED chip is configured to emit radiation in the UVC spectral range; The LED chip forms a light emitting diode (LED) having a package; The LED chip is grown on a bulk AlN or sapphire substrate; the spectral filter element is configured to limit the radiation emitted by the LED chip to wavelengths less than 235 nm, regardless of the angle of incidence of the radiation, primarily by spectral filtering that is independent of the angle of incidence of the radiation; The spectral filter element is A plurality of Al where x ≠ y ｘ G １－ｘ N / Al ｙ G １－ｙ integrated into the epitaxial layer structure of the LED chip as an intrinsic Bragg reflector having N pairs of layers; or AlO ｘ / SiO ２ -HfO as DBR or as dielectric ２ , Ta ２ O ５ , CaF ２ , MgF ２ , Ga ２ O ３ or integrated into the package of the LED as a DBR filter with AlN or applied to the LED chip; or A bandpass filter that is independent of the incident angle of radiation via excitation of surface plasmons, or a Fabry-Perot filter (e is an acute accent above e) that is independent of the incident angle of radiation, when integrated into the package of the LED or applied to the LED chip as an AlOx / SiO2-DBR or as a DBR filter with HfO2, Ta2O5, CaF2, MgF2, Ga2O3 or AlN as dielectric, the shape of the spectral filter element is such that the effective layer thickness through which the radiation traverses the spectral filter element is the same in all spatial directions, the optical element is for directional emission of radiation emitted by the LED; A device, wherein the optical element is designed to conform to the shape of an area illuminated by the device so as to emit light uniformly in the area, thereby achieving spatial uniformity of radiant power.

2. The device of claim 1 , wherein the LED chip is driven for pulsed emission with pulses of maximum 1 μs duration.

3. 2. The device of claim 1, wherein the spatial emission characteristics of the LED are determined by the width, composition and distortion of the band structure of the LED chip, the external geometry of the LED chip, or by reflectors, apertures, lenses and / or potting formed integrated into the package.

4. The device of claim 1 , wherein the optical element comprises a lens, a light pipe, or an optical fiber.

5. The device of claim 1 , wherein the optical element is replaceable.

6. A UV disinfection medical pad comprising a plurality of devices according to claim 1 arranged to form an array, A medical pad, wherein the device is disposed on a flexible or rigid support element.

7. the support element comprises flexible or rigid spacer elements configured to provide a distance between the surface to be disinfected and the devices arranged to form an array when placed on the surface, 7. The medical pad of claim 6, wherein the spacer elements enable irradiation of the surface with radiation emitted by the device.

8. 8. The medical pad of claim 7, wherein the spacer elements are replaceably connected to the support elements.

9. 7. The medical pad of claim 6, wherein at least one monitor diode is integrated into said medical pad as a detector for monitoring the radiant power projected onto the surface to be sterilized.

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