EP4267891A1

EP4267891A1 - Assembly and method for operating luminaires which emit uv radiation with increased safety

Info

Publication number: EP4267891A1
Application number: EP21844710.0A
Authority: EP
Inventors: Andreas Wieser
Original assignee: Smart United Holding GmbH
Current assignee: Smart United Holding GmbH
Priority date: 2020-12-22
Filing date: 2021-12-22
Publication date: 2023-11-01
Also published as: WO2022136578A1; US20240077221A1; DE102020134679A1

Abstract

The invention relates to a method and an assembly having a luminaire (2) which radiates UV light, radiating the UV light in a main propagation direction, wherein at least one surface (3) which is permanently illuminated by the UV light of the luminaire (2) when the luminaire (2) is switched on has a region (4) coated with a material which absorbs UV radiation, the shape and dimensions of the coated region (4) being selected such that all the UV radiation impinging (4) on the illuminated surface (3) with an irradiation intensity above a limit value impinges on the coated region.

Description

Arrangement and procedure for the operation of UV-radiation emitting lights with increased safety

The invention relates to an arrangement and a method that make it possible to operate lamps emitting UV radiation with increased safety, with people being able to be present in the rooms decontaminated by the UV radiation at the same time.

The health importance of hygiene measures in rooms has not only been known since the global corona pandemic, especially in places where a large number of people work together and/or go in and out. Various systems for disinfecting room air with UV radiation have already been proposed.

Useful germicidal radiation is UV radiation. A suitable source of radiation is therefore a large lamp that emits UV radiation in the wavelength range from 100 to 400 m. Within UV radiation, the germicidal effect increases from UV-A to UV-B to UV-C with shorter wavelengths. A lamp which emits UV-C radiation and specifically emits UV-C radiation which is approximately in the wavelength range from 100 to 280 nm is therefore particularly suitable. The wavelength range is preferably from approximately 200 to 28 nm, since air in this range is essentially transparent to the radiation. Known radiation sources of this type are mercury vapor lamps or light-emitting diodes or laser diodes for emitting corresponding UV light.

However, germicidal UV-C radiation can be harmful to human eyes and skin if doses are too high. In principle, the light can be switched off if a person is detected in an area that poses a risk of a person being directly hit by the UV radiation. A switch is coupled to a corresponding sensor and the radiation source and turns them off when the sensor detects the person.

Suitable sensors for detecting the presence of people are motion detectors such as ultrasonic or radar sensors that use the Doppler effect when the ultrasonic or radar radiation emitted by them is reflected on a moving person, or so-called IR PIR sensors that are detect changes in heat radiation in the area surrounding the furniture caused by the person moving. Proximity sensors such as capacitive, optical, ultrasonic or radar sensors are also suitable. that can detect a nearby person regardless of their movement. All of these approaches follow the same basic idea: if a person is detected in the vicinity of the UV radiation source, the source is switched off. The reaction ultimately depends on the respective position of the person. The sensors are arranged in such a way that an approach to the radiation source can be detected. This allows the safe switching off and avoiding direct irradiation of people by the large lamp.

The problem, however, remains that in order to enable a versatile use of such a lamp for killing germs, safe operation in different scenarios must be enabled. The spatial surroundings of a UV lamp intended for killing germs are very different. For each of these applications, however, it must be ensured that personal injury caused by the operation of the UV lamp is reliably avoided. In particular, reflection and scattering of UV radiation on a surface that is hit by the radiation emitted by the UV lamp can also lead to damage to people or animals, although the sensors provided to ensure operational safety detect an approach of the person or animal Tiers towards the UV lamp would be recognized with certainty.

It is therefore the object of the invention to create an arrangement and a method in which damage to living beings by radiation emitted by the UV lamp can be reliably prevented.

This object is achieved by the arrangement according to claim i and the method according to claim 9 according to the invention.

The dependent claims relate to advantageous developments of the invention.

The arrangement according to the invention comprises a lamp that emits UV radiation and emits the UV light in a main direction of propagation, with at least one surface that is permanently illuminated by the UV light of the lamp when the lamp is switched on having a region coated with a material that absorbs UV radiation. A shape and dimensions of the coated area or a bar provided with the appropriate material is selected such that all UV radiation impinging on the irradiated surface with an irradiance above a limit value impinges on the coated area.

The radiation emitted by the UV lamp is generated with a strong directivity, ie in a narrow area around the main radiation direction, unless operation is to take place in a room devoid of people or living beings in general. It radiation is therefore only emitted by the UV lamp in a defined area, so that people can be in other areas of the room anyway, since they cannot be hit by the directly emitted radiation of the UV lamp. The inventive coating of surfaces that are illuminated by this bundled or delimited UV light with an intensity above a limit value with a material that absorbs UV radiation reliably prevents living beings from being endangered by scattered or reflected light radiation occurs. It must be ensured that the radiation-absorbing material is applied to the entire area of the irradiated surface that is impacted by UV radiation where the irradiance is above a defined limit value.

There are limit values for a non-critical irradiance, for example 0.7 microwatts/square centimetre. This limit value can be selected depending on different specifications or legal requirements. Based on a known intensity distribution of the light emitted by the UV lamp, it can then be determined in which area the surface is to be coated. By adapting the shape and surface of the coated area and applying the appropriate coating in the area determined in this way, it is also possible to protect three-dimensionally shaped surfaces lying in the beam path of the emitted UV light. By determining the surface that is actually illuminated with a critical irradiance, the area that could lead to a dangerous reflection or scattering of UV radiation is determined. The UV radiation absorbing material is then applied at least in this area. On the other hand, areas in which the incident radiation is already below the critical limit value do not have to be coated.

The invention can be implemented in a particularly simple manner if the coated area is formed by an adhesive tape provided with the UV light-absorbing material. The adhesive tape in particular can be easily attached to the areas to be secured. This makes a flexible solution possible and the protection can be attached in particular when the UV lamp is being installed. But also a strip on which the absorbent material is applied also significantly improves the variability when building a system for protection against airborne viruses or other pathogens without having to take constructively complicated measures that depend on the respective room .

It is particularly preferred that fluorescent components whose fluorescence is excited by impingement of the UV light are further added to the UV light absorbing material. Such fluorescent components have the advantage that people can directly visually check the emission of UV light, since the operation of the UV Luminaire can be recognized directly from the fluorescent light. This means that people can already see for themselves and without having to provide special sensors whether living beings can move safely anywhere in the room. On the other hand, the fluorescent light can also be used for a power measurement, since the intensity of the incident UV radiation can be determined from a measured intensity of the fluorescent light. In this way, the failure of the system or part of the system can be determined with the help of fluorescent components in the coated area.

A visual check can be carried out particularly easily if the fluorescent components are only arranged in spatially limited partial areas of the coated area. The transitions between the limited partial areas in which fluorescent light occurs and the remaining areas without fluorescent components are preferably sharp. Such edges of objects in an image are easier to recognize when using sensors such as cameras.

The additional arrangement of at least one sensor for detecting the fluorescent light is also preferred, since in such an arrangement an automated detection of changes compared to an initial state is possible. In the simplest case, such a sensor can use the fluorescent light to detect an "on" or "off" state of the system.

The arrangement preferably has an information processing device which is connected to the at least one sensor. The signal output by the sensor, for example a camera and dependent on the detected fluorescent light, can be compared by the information processing device with a comparison signal, so that the lamp can be switched to a safe operating state if there is a difference that exceeds a limit value. In the simplest case, the safe operating state is switching off all UV sources. However, more complex evaluations can also be carried out. For example, in the case of a camera recording, image processing can be carried out as an output signal from the sensor, which allows spatial resolution of areas in which fluorescent light is emitted. The switching off of the emission of UV light can then be limited to those areas in which an impermissible deviation from the comparison signal is detected. A deviation from the comparison signal always occurs when (at least locally) the situation has changed compared to an initial state that has been identified as safe, for example during commissioning. If, for example, despite the UV lamp being switched on, it is recognized in certain areas based on an image taken during operation that the fluorescent light decreases in comparison to the comparison signal, it can be concluded that there is a light in the beam path of the UV light object is located. In this case the system can be switched off, at least locally, so that this area is no longer exposed to UV light.

The comparison signal can be obtained by taking a picture after installing the system and storing the signal recorded by the sensor or the camera in a memory. This stored signal is used as a comparison signal if further recordings are made by the camera (sensor) later on during ongoing operation.

The information processing device can also analyze the difference between the comparison signal and the signal output by the sensor locally and/or with regard to the course over time and classify a current operating state of the arrangement on the basis of the analysis result. For example, as already indicated above, the sudden, local decrease in the intensity of the fluorescent light can be recognized as an object in the area of the emitted radiation. On the other hand, a gradual decrease in intensity can also be observed. For this purpose, the measurement results would have to be stored in a time-resolved manner. Such a gradual decrease may indicate, for example, that a coating applied over a period of time is gradually thinning through wear and tear, thereby losing its protective properties. This is because the decrease in the intensity of the fluorescent light also indicates a decrease in the thickness of the layer with the absorbing material. Typical application examples would be floors, tables or other objects whose surfaces are mechanically stressed. Just cleaning surfaces can wear away the coated area.

Depending on the classified current operating state, a safe operating state corresponding to the classified current operating state is preferably selected from a plurality of safe operating states. As already explained above, for example, the sudden reduction in the measured intensity of the fluorescent light can be recognized as the existence of an object in the beam path, whereas a slow reduction over an area that is also spatially less clearly defined, for example, tends to indicate wear. In the first case, only the relevant part of the lamps can be switched off if individual segments (e.g. groups of lamps) of the UV lamp or if there are several lamps arranged in the room. If, on the other hand, wear and tear of the absorbent coating is detected, the system can be switched off completely and, if necessary, a maintenance measure can be initiated automatically. The failure of individual light sources can also be recognized as a current operating status by such a classification. The individual classes are, for example, assigned in tabular form to the signals supplied by the sensor or their time profiles in a memory that is connected to the information processing device. The invention is explained in more detail below with reference to the accompanying drawings using a preferred exemplary embodiment. Show it:

Figure i shows a greatly simplified perspective representation of the arrangement according to the invention, in which a flat surface is illuminated by UV light from a lamp,

FIG. 2 shows a schematic representation of an arrangement in which the coated area contains fluorescent components whose fluorescent light is recorded by a camera for situation recognition,

FIG. 3 shows a plan view of a coated area with absorbent material and fluorescent components, and

FIG. 4 shows a simplified flow chart for explaining the method according to the invention.

FIG. 1 shows an arrangement according to the present invention, as it can be used, for example, in a room frequented by people. The arrangement 1 comprises a lamp 2, through which UV light, preferably UV-C light, is emitted. The emission of the UV light is shown schematically in FIG. 1 by the arrows. The emitted UV light is emitted by the lamp 2 in such a way that it propagates only in the plane characterized by the arrows, the extension perpendicular to the defined plane being narrow compared to the area of the plane.

Although the preferred application is such a narrow radiation field that is generated by the lamp 2, the invention can generally be used whenever UV radiation is emitted in a spatially limited area and this emitted UV radiation strikes a surface.

A surface 3 is shown in FIG. 1, which is a flat surface and can be, for example, a floor or a table if the luminaire 2 is mounted on a ceiling in a room. The surface 3 generally designates a surface opposite the lamp in the main emission direction, onto which the UV light emitted by the lamp 2 strikes. According to the invention, this surface 3 is now provided with a coated area 4, this coated area 4 having UV-radiation-absorbing material in the layer. The position and extent of the coated area 4 is selected in such a way that all UV radiation emitted by the lamp 2 and impinging on the surface 3 with an irradiance above a specified limit impinges within the coated area 4 . The arrangement of a coated area 4 with material absorbing UV radiation ensures that people are not endangered by reflected or scattered radiation components of the UV radiation, even if people are present in a room containing the lamp 2 . In order to enable the lamp 2 to be used to form a barrier for bacteria and viruses in a room, the coated area 4 ensures that even if the nature of the surfaces 3 on which the UV light emitted by the lamp 2 hits is not known, but safe operation is still possible. The formation of the coated region 4 spatially limited, yet sufficiently extensive, allows the use of a lamp 2 emitting UV light in practically all conceivable spatial situations. For adaptation, the coated area 4 is adapted depending on the geometry of the illuminated surface 3 and the irradiance of the incident radiation on the surface 3.

For a more precise understanding of the mode of operation and in particular the further possibilities of using the coated area 4 to analyze the operating state or failure of individual lamps, a lamp 2 or entire lamps 2, FIG. 2 shows a further schematic illustration. The arrangement 1, which essentially corresponds to the arrangement 1 already shown with reference to FIG. It is understandable that all of the components required for the evaluation or activation of the lighting means of the lamp 2 can also be arranged in the lamp 2 or its housing 5 .

In addition to the housing 5, the lamp 2 has a reflector 6 which bundles the radiation emitted by one or preferably a plurality of lamps in such a way that the UV radiation generated emerges from the lamp 2 in the direction of the arrow. The bundling with the aid of optical elements, the reflector 6 in the exemplary embodiment shown, is carried out in such a way that the beam exits only within the area defined by the two dashed lines on either side of the arrow which indicates the main direction of radiation. Together with the illustration in FIG. 1, it can be seen that such a narrow “wall” of UV radiation is built up as a barrier for pathogens. A passage of viruses or other pathogens from one side of this UV wall to the other side kills the pathogens. This creates an effective barrier for viruses or other pathogens.

In order to enable the safe operation of such a lamp 2, various safety measures are provided, which are not shown in FIG. 2 for the sake of clarity and can also be used independently of the use of a coated area 4 proposed here. In particular are Provide protective mechanisms which are formed on both sides of the radiation field, ie, for example, parallel to its boundary planes indicated by the dashed lines. These prevent an object or part of a person's body from getting into the UV wall from the side. For this purpose, when an intrusion into a security zone is detected, the lamp 2 or part of it is switched off, so that UV radiation is no longer emitted by the lamp 2 in the area in which an intrusion of an object into the security zone was detected.

In the simple example shown in FIG. 2, the UV light emitted by the lamp 2 impinges on a surface 3 which is oriented perpendicular to the main direction of emission. However, the invention is particularly advantageous when this surface 3, or at least parts of it, does not run exactly perpendicular to the main emission direction. With regard to a possible risk to people in the room in which the arrangement 1 is present, a perfectly reflecting surface 3, which reflects the UV light in the opposite direction to the main emission direction, would be comparatively uncritical. On the other hand, situations are more dangerous in which the light striking the surface 3 is reflected at an angle to the main emission direction. In this case, the additional safety precautions described above cannot prevent parts of the body from being hit by the reflected UV light.

In the illustrated embodiment, the coated area 4 contains both UV radiation absorbing material and fluorescent material. The fluorescent material reacts to the incident UV radiation and emits light through spontaneous emission, which is in a different wavelength range that is not critical for living beings. A camera 8 is arranged as a sensor on the lamp 2 and generates an image of at least the coated area 4 . In particular, the image depicts those areas that emit fluorescent light. As will be explained below with reference to FIG. 3, the entire surface of the coated area 4 does not have to be provided with the fluorescent material. It is also sufficient if individual partial areas of the coated area 4 have such a fluorescent component.

The image recorded by the camera 8 is fed to a controller 9 . In addition to a processor 10, which serves as an information processing device, the controller 9 also includes a memory 11. Comparative information obtained from an image is stored in the memory 11, the image being recorded for this purpose in a safe operating state, which is present, for example, when the system is started up will. In the information processing device, ie by the processor 10, during normal operation of the UV lamp 2, a comparison between the comparative information and the corresponding information obtained from the currently recorded image of the camera 8 can be carried out.

A conclusion about the current operating situation in which the UV lamp 2 is being operated can be drawn from a comparison of the information from these two recordings, possibly also taking into account other images recorded over the course of time. In the simplest case, a decrease in the fluorescent light is determined by comparing the information from the current image with the comparative information, and the UV lamp 2 is switched off as a reaction to this.

Examples of other operating states or deviations from a target irradiance can also be determined on the basis of the images recorded by the camera 8 . For example, a merely local reduction in the intensity of the fluorescent light can also be interpreted in such a way that an object is only present in a certain area between the actual radiation source, i.e. the lamp 2, and the surface 3, which the irradiation of the surface 3, and thus ultimately the emergence of the fluorescent light, prevented locally. On the other hand, a gradual decrease in the illuminance can also be recognized if, for example, the intensity of the fluorescent light decreases uniformly. In this case, a maintenance measure could also be triggered if the controller 9 outputs a corresponding information signal.

The use of fluorescent components in the coated area 4 also has the advantage that situations in which other safety mechanisms fail still lead to safe operation of the arrangement 1. Depending on the evaluation of the image generated by the camera 8, the lamp 2 is brought into a safe operating state. The safe operating state can be that the lamp 2 is switched off as a whole, only parts of it are switched off or, if several lamps 2 are operated together, part of the lamps 2.

A corresponding signal containing the information as to which parts of a lamp 2 or which lamps 2 are to be switched off is transmitted to the operating device 12 in the controller 9 . Particularly in the case of multiple lights 2, multiple operating devices 12 can also be present. Alternatively, a multi-channel operating device 12 can also be used. On the basis of this signal, the lamp 2 or the plurality of lamps 2 is then actuated accordingly by the operating device 12 or the entirety of operating devices 12, so that the area for which a reduction in the fluorescent light was recognizable is switched off. The procedure described above is a significant gain in security. It is possible, with the help of other safety devices, to detect the intrusion of objects into the area between the dashed lines and accordingly switch off the UV light at least locally. However, if only safety zones were used on either side of the dashed lines, objects placed in the gap, for example, would not lead to the UV radiation being permanently switched off for this area. A reflecting object can serve as an example, for example a mirror ball, which is brought into the irradiated area by a person. If this mirror ball is too small to permanently trigger the safety devices on both sides of the irradiated area, the UV light would be switched on again after the hand was withdrawn from the safety zone. With the aid of the invention, it is now nevertheless recognized that the fluorescent light is no longer emitted in the area of the mirror ball in the image recorded by the camera 8 . In response to this, the arrangement 1 is brought into a safe operating state, ie the UV light is switched off at least locally for this area.

To produce the coated area 4, an adhesive tape can be used for particularly simple formation of the coated area 4 when assembling the arrangement 1, to which absorbent material is applied, for example in a printing process, preferably additionally fluorescent material. An example of a pattern that could be used is shown in FIG. FIG. 3 shows only one coated area 4, the coated area 4 having the absorbent material over its entire surface. In addition, parts of the area that are shown in FIG. 3 as triangles with different orientations have fluorescent material. It can be seen that absorbing material is also present in the area where fluorescent material is applied. This is important, otherwise reflection could occur in these areas.

The areas in which the fluorescent material is present are shown in FIG. 3 as triangles, merely by way of example. Other geometries are conceivable, as is a uniform introduction of fluorescent material. However, the use of sharply defined geometries makes processing in the information processing device easier since high contrast between fluorescent areas and non-fluorescent areas is easier to see.

FIG. 4 shows a simplified flow chart for carrying out the method according to the invention. First, in step Si, it is determined what the shape and size of the area 4 to be coated should look like. This can be done either mathematically, if the geometries of the room in which the lamp 2 is to be installed are known, or experimentally, ie by measuring the irradiance actually incident on the surface 3 . In the next step, S2, the surface 3 is then coated to produce the coated region 4, wherein at least UV radiation-absorbing material, preferably with portions of fluorescent material, is applied for the coating.

In addition to the already mentioned coating with the help of an adhesive tape, alternatively the application of a paint containing appropriate pigments, it is also conceivable to mount prefabricated absorber strips or absorber surfaces on carriers.

In the next step, S3, after the assembly or application of the coated area 4, an image is taken with the lamp 2 switched on in order to obtain comparative information. This comparison information is stored in memory 11 and is available for subsequent evaluation of images recorded at a later point in time.

These additional images are recorded in step S4 during regular operation of the lamp 2 and are transmitted from the camera 8 to the processor 10 . As already described above, the processor 10 as an information processing device carries out an analysis either only of the last recorded image or an analysis of the course over time. It should be noted that, in order to avoid errors in the decision, a plurality of images are also averaged instead of just one last image taken and the information for further analysis can be obtained from this, which is then evaluated.

In order to evaluate the image information, it is determined in step S5 whether the deviation from the comparison information exceeds an adjustable limit value. The limit value can be set depending on legal requirements or individual safety requirements. A deviation does not have to be present over the entire surface of the coated area 4; it is sufficient if such a deviation is only detected in a partial area. In particular, a spatially resolved detection of deviations is to be preferred when it is possible to selectively switch off parts of the lighting means of a lamp 2 .

According to a preferred exemplary embodiment, the deviations from the limit value, possibly including the time profile, are used to classify the current operating situation in step S6. Depending on the detected operating situation, the safe operating state to be used is selected in step S7, with which the lamp 2 is then to be operated. For each of the possible classes that can be assigned in step S6, a corresponding safe operating state is stored in a table in memory 11, for example. The information processing device selects the appropriate, safe operating state from this table and transfers it to the control gear or the plurality of control gears 12. The control gear 12 then in turn control the illuminants of one lamp 2 or of the plurality of lamps 2.

As already briefly explained above, it is particularly preferred that additional safety devices are present. Irrespective of the existence of such additional safety devices, however, it must be ensured that the absorbing material has sufficient ability to absorb UV radiation from the UV light emitted by the lamp 2, so that the irradiance of the highest radiation intensity emitted by the lamp 2 may still be reflected Residual light remains below safety-relevant limit values.

Claims

Expectations

1. Arrangement with a lamp (2) that emits UV light and emits the UV light in a main propagation direction, wherein at least one surface (3) that is permanently illuminated by the UV light of the lamp (2) when the lamp (2) is switched on has a with an area (4) coated with a material that absorbs UV radiation, the shape and dimensions of the coated area (4) being selected such that all UV radiation impinging on the surface (3) irradiated with an irradiance above a limit value is incident on the coated area (4) meets.

2. Arrangement according to claim 1, characterized in that the coated area (4) is formed by an adhesive tape provided with the UV light absorbing material.

3. Arrangement according to claim 1 or 2, characterized in that the UV light-absorbing material also has fluorescent components whose fluorescence is excited by impingement of the UV light.

4. Arrangement according to claim 3, characterized in that the fluorescent components are arranged only in spatially limited partial areas of the coated area.

5. Arrangement according to one of claims 3 or 4, characterized in that the arrangement has at least one sensor (8) for detecting the fluorescent light.

6. Arrangement according to claim 5, characterized in that the arrangement (1) further comprises an information processing device (10) which is connected to the at least one sensor (8) and one of the sensor (8) output from which detected fluorescent light-dependent signal with a comparison signal and in the presence of a limit-exceeding difference, the lamp (2) switches to a safe operating state.

7. Arrangement according to claim 6, characterized in that the information processing device (10) is set up to analyze the difference between the comparison signal and the signal emitted by the sensor (8) and to classify a current operating state of the arrangement (1).

8. The arrangement as claimed in claim 7, characterized in that the information processing device (10) is also designed to select a safe operating state surface corresponding to the classified current operating state from a plurality of safe operating states depending on the classified instantaneous operating state.

9. A method for the safe operation of a UV light emitting luminaire, the method comprising the following steps:

• Determining (Si) a shape and dimension of an area of a surface (3) illuminated by the lamp (2) with the UV light such that all UV radiation impinging on the illuminated surface (3) with the irradiance above a limit value is within this area lies, and

• Coating of the surface (3) at least in the determined area (S2) with a material that absorbs UV radiation.

10. The method according to claim 9, characterized in that an adhesive tape provided with the UV light-absorbing material is applied to form the coated area (4).

11. The method according to claim 9 or 10, characterized in that fluorescent components are added to the UV light absorbing material.

12. The method according to claim 11, characterized in that 15

• Fluorescent light emitted by the fluorescent components is detected (S4) when the lamp (2) is switched on.

• a signal dependent on the detected fluorescent light is supplied to an information processing device (10), which signal is compared (S5) with a comparison signal by the information processing device (10), and

• if a difference exceeding a limit value is detected between the comparison signal and the signal emitted by the sensor (8), the lamp (2) is switched to a safe operating state (S8).

13. The method according to claim 12, characterized in that the information processing device (10) analyzes the difference between the comparison signal and the signal emitted by the sensor (8) and classifies a current operating state of the arrangement (S6).

14. Method claim 12, characterized in that the information processing device (10) further, depending on the classified current operating state, selects a safe operating state corresponding to the classified current operating state from a plurality of safe operating states (S7).