FIELD OF THE INVENTION

The invention relates to a system for disinfection using short- wavelength radiation and air ionization. Further, the invention relates to a method for disinfection using short-wavelength radiation and air ionization.

BACKGROUND OF THE INVENTION

The use of UV-light for disinfection of surfaces is known in the art. WO2015/189615, for instance, describes a disinfection system comprising: a luminaire assembly for generating a UV-C output suitable for disinfecting a surface upon which the UV-C is incident; a control system for controlling the UV-C output of the luminaire assembly and a remote monitoring device in communication with the control system, wherein, in use, the remote monitoring device generates a measured UV-C intensity based upon the intensity of the UV-C output of the luminaire assembly detected by the remote monitoring device at the location of the remote monitoring device.

SUMMARY OF THE INVENTION

UV light has been used for disinfection for over 100 years. Wavelengths between about 190 nm and 300 nm may be strongly absorbed by nucleic acids, which may result in defects in an organism’s genome. This may be desired for killing bacteria and viruses, but may also have undesired side effects for humans. Therefore the selection of wavelength of radiation, intensity of radiation and duration of irradiation may be limited in environments where people may reside such as offices, public transport, cinema’s, restaurants, shops, etc., thus limiting the disinfection capacity. Especially in such environments, additional measures of disinfection may be advantageous to prevent the spread of bacteria and viruses such as influenza or novel (corona) viruses like CO VID-19, SARS and MERS.

It appears desirable to produce systems, that provide alternative ways for disinfection in addition to short-wavelength radiation, in regions and/or at times where the short-wavelength radiation is not sufficient for killing microorganisms. Further, existing systems for disinfection may not easily be implemented in existing infrastructure, such as in existing buildings like offices, hospitality areas, etc. and/or may not easily be able to serve larger spaces. This may again increase the risk of contamination. Further, incorporation in HVAC systems may not lead to desirable effects and appears to be relatively complex.

Hence, it is an aspect of the invention to provide an alternative system for disinfection, which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

A method for disinfection may be the use of air ionizers. Microorganisms may be killed by positive ions and/or negative ions in air. Therefore, in embodiments ionized air may be applied in regions and/or at times where disinfection with short-wavelength radiation only is not sufficient and/or may be less desirable.

Hence, in a first aspect the invention provides a system comprising a unit, wherein the unit comprises (i) a radiation generating device and (ii) an air ionizer. The radiation generating device may be a light source configured to generate device radiation, which is selected from UV, VIS and IR. In embodiments, the air ionizer, for example in that it comprises an ion emitter, is configured to generate ionized air, especially with a volumetric ion flow rate Q. In embodiments, the system is configured to generate the device radiation which (at least) comprises one or more wavelengths selected from the range of 100-430 nm, especially in the range of 100-420 nm. This radiation is herein also indicated as “shortwavelength radiation”. In embodiments, the device radiation has an angular dependent intensity distribution of device radiation intensity I, having a maximum intensity I _max . Especially in embodiments, in a first angular part of the angular dependent intensity distribution a first intensity Ii of the device radiation is at least ai*I _ma x, wherein 0<ai<l. Especially, in a second angular part of the angular dependent intensity distribution a second intensity E of the device radiation may be smaller than ai*I _ma x. In embodiments, the system may be configured to generate the ionized air having a first volumetric ion flow rate Qi within at least part of the first angular part and a second volumetric ion flow rate Q2 within at least part of the second angular part; wherein in embodiments Q2>QI. Especially in embodiments, in at least part of the first angular part, the first intensity Ii of the device radiation is Ii>ai*I _ma x. In specific embodiments, in the first angular part, the first intensity Ii of the device radiation thus is selected from the range of Ii>ai*I _max . In embodiments, in the first angular part, the first volumetric ion flow rate Qi may be smaller than the second volumetric ion flow rate Q2 in the second angular part, thus Q2>QI. Especially, in embodiments, in at least part of the first angular part, the first volumetric ion flow rate Qi is smaller than the second volumetric ion flow rate Q2 in at least part of the second angular part, thus Q ₂ >QI. In embodiments Q2>QI, especially Q2>1.2*QI, more especially Q2>1.5*QI. In specific embodiments Q2>2*QI, especially Q2>5*QI, more especially Q2>7*QI. In embodiments wherein Q2 is defined in terms of Qi, Q2 is mathematically dividable by Qi (thus there is at least some ion flow in Qi). In embodiments, Q2/Qi<10000, especially Q ₂ /QI<1000, more especially Q2/QI<100. Therefore, in specific embodiments the invention provides a system comprising a unit, wherein the unit comprises (i) a radiation generating device and (ii) an air ionizer, wherein the radiation generating device is configured to generate device radiation, and wherein the air ionizer is configured to generate ionized air; wherein the system is configured to: (a) generate the device radiation comprising one or more wavelengths selected from the range of 100-430 nm, especially in the range of 100-420 nm, wherein the device radiation has an angular dependent intensity distribution of device radiation intensity I having a maximum intensity Imax; wherein in a first angular part of the angular dependent intensity distribution a first intensity Ii of the device radiation is at least ai *Imax, wherein 0<ai<l, and wherein in a second angular part of the angular dependent intensity distribution a second intensity I2 of the device radiation is smaller than ai*I _ma x; and (b) generate the ionized air having a first volumetric ion flow rate Qi within at least part of the first angular part and a second volumetric ion flow rate Q2 within at least part of the second angular part; wherein Q2>Qi. The angular distribution of the device radiation over first, second and further parts can easily be attained by angular distribution means well- known to persons skilled in the art, for example by optical means like filters, lenses, reflectors, refractors, louvers, and/or by physical/electric means like orientation, packing density, distribution of individual light sources (like LEDs), sub-group or individual control of light sources that functions as radiation generating means.

Such a system provides a larger distribution of disinfection properties, where a lower short wavelength radiation intensity typically is compensated with higher ion concentration to have a wider surface area range of disinfection when adding up the two disinfection properties of the different technologies. Using this system, it may be possible for short-wavelength radiation and ionized air to complement one another in order to achieve the intended effectiveness of disinfection. The effectiveness of disinfection may e.g. be defined as the percentage of microorganisms that is killed by the system. Further, the system may allow a relative easy integration in existing lighting systems and may e.g. allow a grid of units. This may facilitate a relative even disinfection over rooms, in contrast to disinfection systems that are implemented in (existing) climate control systems.

In embodiments, the (UV) radiation may be used for disinfection of one or more of (i) bacteria, and (ii) viruses. In embodiments, the ionized air may be used for disinfection of one or more of (i) bacteria, and (ii) viruses. Other terms for air ionization that may be used are “plasma cluster ionization” or “needle point bi-polar ionization (NPBI)”, which are considered to be equivalent to air ionization.

In embodiments, the intensity of the device radiation may be defined as luminous flux, in lumen, measured at a predefined distance, especially in embodiments 1 meter from the radiation source. However, in embodiments other intensity parameters may also be used, as herein especially relative intensities are applied. In embodiments, the volumetric ion flow rate may be defined as the number of ions that pass per volume per unit time, e.g. in ions per cubic meter per second.

In embodiments, the air ionizer may produce negative ions. In embodiments the air ionizer may produce positive ions. In embodiments, the air ionizer may produce positive and negative ions, such as at different positions. Herein, the volumetric ion flow rate does (essentially) not discriminate between positive or negative ions.

In embodiments, the air ionizer may comprise needles or brushes functioning as ion emitters. In embodiments, the ion emitters may comprise one or more of tungsten, titanium, steel, and carbon, such as needles or brushes comprising one or more of tungsten, titanium, steel, and carbon. In embodiments, ions may be generated on the basis of the corona effect. In specific embodiments, needlers or brushes are used pointing in a direction within an angle of 0-75°, such as within an angle of 0-60° from an optical axis (see also below).

In embodiments, the air ionizer may comprise a fan. Such fan may produce an air flow in a target direction which may transport ions produced by the air ionizer in the target direction. The term “fan” may refer to any device that can generate a flow, with or without rotating blades. Further, the term “fan” may also refer to a plurality of (individually controlled) fans. The term “air ionizer” may also refer to a plurality of air ionizers.

In alternative embodiments, the air ionizer may not comprise a fan. In this case, ions produced by the air ionizer may diffuse out of the air ionizer. Alternatively, the ions produced by the air ionizer may be transported by air flow that is already present, e.g. caused by heating, ventilation air conditioning (HVAC) systems. In such embodiments, ions that may propagate away from the ionizer may be entrained by an air flow that is already present in a space. Note that in case of embodiments of the air ionizer with a fan, also the air flow already present may influence, such as assist, in distributing the ionized air (in the space). Volumetric flow rates within first, second and further angular parts can, for example, easily be controlled by flow regulation means like individual fans, valves, diaphragms, shutters, louvers etc.

For both an (UV) radiation generating device and an air ionizer it may be advantageous to be located at a ceiling or otherwise over a floor, such as suspended from a roof, etc.. In this way, the amount of obstruction by other elements, like chairs, desks, cupboards, cubicle walls, etc., may be minimized and large areas may be treated (with one or more units). As many locations are provided with downlighting based systems, these might be an efficient way to incorporate the herein proposed system. Thus, in embodiments, the system may be incorporated in a downlight based system (“downlighf ’), like a (downlighting) luminaire or (downlighting) spotlight.

Short-wavelength radiation comprises a range of wavelengths. Amongst others, herein the term “short- wavelength radiation” may in embodiments refer to at least part of the UV radiation wavelengths, which may be defined as in the range of about 100-380 nm. Short-wavelength radiation may also refer to at least part of the blue wavelength range, especially in the range of 380-420 nm. Hence, the term “short- wavelength radiation” may refer to one or more wavelengths selected from the range of 100-420 nm, such as 190-420 nm, like in the range of 190-315 nm, such as e.g. 190-280 nm. The terms “light” and “radiation” are herein interchangeably used, unless clear from the context that the term “light” only refers to visible light.

Different wavelengths of radiation have different properties and thus may have different compatibility with human presence and may have different effects when used for disinfection. In embodiments, the short-wavelength radiation may be safe short- wavelength radiation, especially one or more wavelengths selected from (i) (violet) light in the range of 400-420 nm, (ii) UVA in the range of 315-400 nm, and (iii) far UV in the range of 190-230 nm. Alternatively, the short- wavelength radiation may be selected from the range of 230-315 nm. The latter may e.g. be useful for (temporarily) unoccupied spaces. Thus, in specific embodiments, the device radiation may comprise one or more wavelengths selected from one or more of the following ranges: 190-230 nm, 230-280 nm, 280-315 nm, 315-400 nm, and 400-420 nm.

In embodiments, the device radiation may comprise one or more wavelengths selected from the range 190-230 nm. This wavelength range may be referred to as far UV and may be more safe for humans whilst being more effective in killing bacteria and viruses. Alternatively or additionally, in embodiments, the device radiation may comprise one or more wavelengths selected from the range 230-280 nm. This wavelength range may be referred to as UV-C excluding far UV and may be effective in killing bacteria and viruses. However, this wavelength range may be less safe for humans and animals. Alternatively or additionally, in embodiments, the device radiation may comprise one or more wavelengths selected from the range 280-315 nm. This wavelength range may be referred to as UV-B and may kill bacteria and viruses. Alternatively or additionally, in embodiments, the device radiation may comprise one or more wavelengths selected from the range 315-400 nm. This wavelength range may be referred to as UV-A and may be effective in killing bacteria. Viruses may be less likely to be killed by UV-A, but this radiation may be more safe for humans that UV-B and UV-C. Alternatively or additionally, in embodiments, the device radiation may comprise one or more wavelengths selected from the range 400-430 nm, especially from the range 400-420 nm and more especially from the range 400-410 nm. Violet light may be able to kill bacteria but may not be able to kill viruses. This wavelength range is safe. Especially, short-wavelength radiation in the range of 100-280 nm may be efficient to kill microorganisms. Short-wavelength radiation in the range of 100-190 nm may create ozone and may be less desirable. Hence, in specific embodiments during operation or an operational mode, or at least part of the time of the operational mode, the shortwavelength radiation may have one or more wavelengths selected from the range of 190-280 nm, such as 190-230 nm.

When irradiating a space with radiation from a radiation generating device, when short-wavelength radiation is available, this may be used for disinfection purposes. Hence, as also indicated above, with the short- wavelength radiation bacteria and/or viruses may be eliminated. However, the radiation may also have different intensities in different directions. Often, the intensity may be at maximum along the optical axis, and may gradually decrease with increasing angle from the optical axis. In the case of batwing intensity distributions, this may be different. However, also in the case of batwing intensity distributions, there is an angular distribution of the intensity of the radiation. Hence, when the radiation comprises short-wavelength radiation, which may (even) be the case when using visible radiation, in some angular directions the disinfection may be more efficient than in other directions. Or, in some directions the elimination may be achieved along a longer distance from the radiation generating device than in other directions. This may lead to a less optimal or even undesirable disinfection results. With the present invention, however, this may be solved as in directions with a lower disinfection result based on the short- wavelength radiation, the disinfection via ionization may be stronger, whereas in directions wherein a better disinfection result based on the short- wavelength radiation may be achieved, the disinfection via ionization can be less pronounced. Therefore, the short-wavelength radiation beam may be divided in two or more angular directions or angular parts, based on intensity of the short-wavelength radiation, wherein in a part with a lower intensity of the shortwavelength radiation, e.g. at larger angles from the optical axis, the production of ions may be larger, than in a part with a higher intensity of the short-wavelength radiation.

Herein, the symbol “I” is used for intensity in general, and may refer to both the first intensity and the second intensity (and optional further intensities, see also below). Herein, the symbol Q is in general used for the ion volumetric ion flow rate, and may refer to both the first volumetric ion flow rate and the second volumetric ion flow rate (and optional further volumetric ion flow rates, see also below).

An angular part may especially define a part of a three dimensional space surrounding the system. The angular part may be defined relative to the optical axis Ax (see below). The angular part may be centrosymmetric relative to the optical axis. The angular part may be defined relative to a plane or relative to two orthogonal planes, which may in embodiments comprise the optical axis. The angular part may be asymmetric. The angular part may have an elongated shape in one direction, e.g. when an elongated light source may be used. The use of the term “angular part” does not necessarily imply that the radiation generating device is essentially a point light source. The radiation generating device may e.g. be a spotlight, which may be considered in embodiments a point light source. However, the radiation generating device may also be an elongated luminaire.

The radiation generating device may comprise a light transmissive window, like a spot light, or may comprise a light transmissive window in a housing (such as an opening or a light transmissive material comprising window), through which the radiation may be issued by or may be emitted into the exterior environment by the radiation generating device. Relative to the radiation generating device, the space downstream of the radiation generating device may be divided in at least two angular parts.

The terms “upstream” and “downstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here the especially the light source), wherein relative to a first position within a beam of light from the light generating means, a second position in the beam of light closer to the light generating means is “upstream”, and a third position within the beam of light further away from the light generating means is “downstream”. The intensity of the device radiation in the first angular part is indicted with first intensity Ii. The first intensity Ii of the device radiation in the first angular part may be related to the maximum intensity of the device radiation I _max by a factor ai. Especially, in at least part of the first angular part, the intensity Ii of the device radiation may be at least ai*Imax. Therefore, in embodiments Ii>ai*I _ma x, wherein 0<ai<l. Within the first angular part, the intensity of the device radiation Ii may also vary (over the angle). Especially, in embodiments in the entire first angular part Ii>ai*I _ma x, with 0<ai<l.

The intensity of the device radiation in the second angular part is indicated with second intensity h. Especially, in embodiments, in at least part of the first angular part the device radiation E has a higher value than the second intensity h of the device radiation in at least part of the second angular part. Hence, in embodiments in at least part of the second angular part, the intensity E of the device radiation may be at maximum ai*I _max . Within the second angular part, the intensity of the device radiation E may also vary (over the angle). Especially, in embodiments in the entire second angular part l2<ai*I _ma x. Especially, in embodiments in at least part of the (entire) second angular part l2>0.01*ai*I _max . In embodiments, Ii/l2<l 0000, especially Ii/l2<l 000, more especially Ii/l2<l 00.

In specific embodiments, 0.25<ai<l such as 0.25<ai<0.75, especially in embodiments 0.4<ai<0.6. In embodiments, l2<ai*I _ma x, especially l2<0.95*ai*I _ma x. This may in embodiments imply that the first intensity or first intensities in the first part are at least 25% of the maximum intensity, and the second intensity or second intensities in the second part are smaller than 25% of the maximum intensity. In yet other embodiments, may in embodiments imply that the first intensity or first intensities in the first part are at least a value selected from the range of 40-60% of the maximum intensity, and the second intensity or second intensities in the second part are smaller than that selected value of the maximum intensity, etc.

Therefore, in embodiments the radiation generating device and the air ionizer may be configured to: (a) generate (in the operational mode) the device radiation comprising one or more wavelengths selected from the range of 100-420 nm, wherein the device radiation has an angular dependent intensity distribution of device radiation intensity I having a maximum intensity I _ma x; wherein in a first angular part of the angular dependent intensity distribution a first intensity E of the device radiation is at least ai*I _ma x, wherein 0<ai<l, and wherein in a second angular part of the angular dependent intensity distribution a second intensity I2 of the device radiation is smaller than ai*I _ma x; and (b) generate (in the operational mode) the ionized air having a first volumetric ion flow rate Qi within at least part of the first angular part and a second volumetric ion flow rate Q2 within at least part of the second angular part; wherein Q2>QI.

In embodiments, the system may further comprise a control system, wherein the control system may be configured to control the output of the radiation generating device and/or the air ionizer, in embodiments in dependence of one or more of a user interface, a sensor, and a timer. The output typically relates to: for the radiation: the spectral composition, like the intensity, color, UV- amount, of individually controllable LEDs, switchable filters; and for the spatial distribution, like beam direction, beam angle (FWHM), by adjustable diffusers, louvers and/or fan(s).

Especially, the radiation generating device and the air ionizer may be controlled individually. Especially, the timer may comprise in embodiments a time scheme. In embodiments, the system may control one or more of the radiation generating device and the air ionizer, in embodiments in dependence of a clock module (or timer). The clock module may provide a time scheme. The control system, especially in combination with the sensor, may provide the system with instructions for changing from a first operational mode to a second operational mode, depending on signals from the sensor. In embodiments, the control system may receive signals from a user interface, such that a user can control one or more of (i) device radiation wavelength, (ii) device radiation intensity, and (iii) ionized air volumetric ion flow rate.

In embodiments of the second operational mode, for instance the radiation may comprise less (intensity of) short wavelength radiation. For instance, the first intensity and the second intensity of the short wavelength radiation may in the second operational mode be less than 5%, such as less than 2% of Imax at maximum power of the radiation generating device. Alternative or additional to less short wavelength radiation, in the second operational mode the (first and the second) volumetric ion flow may be smaller than at maximum power of the air ionizer, such as in embodiments less than 5%, such as less than 2% of the (first and the second) volumetric ion flow at maximum power of the air ionizer.

In embodiments, the sensor may comprise one or more sensors selected from the group comprising: a movement sensor, a presence sensor, a distance sensor, an ion sensor, a gas sensor, a virus sensor, an airflow sensor, a radiation sensor, a bacterium sensor, and a communication receiver. Especially, when the sensor detects movement or presence, the control system may be configured to select the one or more wavelengths (in dependence of a sensor signal of such sensor(s)). In this way, the system may prevent humans to be exposed to harmful radiation. In embodiments, the control system may be configured to control the volumetric ion flow rate Q in dependence of the sensor. Especially, the control system may in embodiments increase the volumetric ion flow rate Q when movement or presence is detected. Vice versa may also be the case: in embodiments, the volumetric ion flow rate Q may be decreased when no movement or presence is detected. In alternative embodiments, the control system may in embodiments decrease the volumetric ion flow rate Q when movement or presence is detected. Thus, in specific embodiments, the sensor may comprise one or more of a presence sensor and a movement sensor, and wherein the control system is configured to (i) (a) decrease 230-315 nm wavelength radiation and/or (b) to increase the volumetric ion flow rate Q upon detection of movement or presence by the sensor, and (ii) (a) to increase the 230-315 nm wavelength radiation and/or (b) to decrease the volumetric ion flow rate Q when no movement or presence is detected by the sensor.

The term “sensor” may also refer to a plurality of (different) sensors. As indicated above, the system may provide for short-wavelength radiation and ionized air to complement one another in space. Additionally or alternatively, the system may provide for short-wavelength radiation and ionized air to complement one another in time. As indicated above, it may be desirable to select device radiation wavelength depending on the presence of humans. In embodiments, one or more of (i) device radiation wavelength, and (ii) device radiation intensity, may depend on a presence of humans. This may result in suboptimal disinfection conditions by short-wavelength radiation, such as UV radiation, only. Therefore, in embodiments, the ionized air volumetric ion flow rate Q may depend on the device radiation intensity. In embodiments, ionized air volumetric ion flow rate Q may depend on the device radiation wavelength.

In specific embodiments, the control system is configured to control the volumetric ion flow rate Q in dependence of the device radiation intensity I. For instance, when the device radiation intensity increases, the volumetric ion flow rate Q may decrease. For instance, when it is getting darker outside, the intensity of the device radiation may be increased. In such instance, the volumetric ion flow rate Q may be decreased. Likewise, on a sunny day, the device radiation intensity may be low; in such embodiments the volumetric ion flow rate Q may be increased. In specific embodiments, the sensor may therefore comprise an ambient light sensor. The fact that the volumetric ion flow rate Q may be increased or decreased in general, may still allow that there are different volumetric ion flow rates (Q _n ) in different angular parts (as amongst others indicated above). As indicated above, the intensity of the device radiation may have an angle dependent distribution. Hence, with changing angle, the intensity may also change. In embodiments, at certain angles the intensity may even be essentially zero, though in other embodiments, the smallest intensity at certain angles may be unequal to zero. At angles with high intensities, the volumetric ion flow rate Q may be low, or even be essentially zero. However, at angles with lower intensities of the radiation, it may be desirable that the volumetric ion flow rate Q is also angular dependent, and may increase when the intensity decreases as function of the angle. Intermediate values of intensities I and volumetric ion flow rates Q, respectively, may in embodiments thus also be possible.

Hence, in embodiments, the system may be configured to generate the ionized air with the volumetric ion flow rate Q having an angular dependent volumetric ion flow rate within one or more of the first angular part and the second angular the second angular part, especially within at least the second angular part. The volumetric ion flow rate Q may have a maximum volumetric ion flow rate Qmax. In embodiments, the maximum volumetric ion flow rate Qmax may be provided in the second angular part of the angular dependent intensity distribution, though this is not necessarily the case.

Note that the term “maximum volumetric ion flow rate Qmax” especially refer to the maximum volumetric ion flow rate provided during operation. Likewise, the maximum intensity Imax is especially the maximum intensity provided during operation. These maximum values, respectively, are not necessarily the maximum achievable values with the air ionizer or radiation generation device, respectively.

In embodiments, a spot shaped light distribution may comprise Imax, wherein the ionized air (flow) may (at least partly) be arranged as a ring shape around Imax, comprising Qmax. In embodiments, Qmax may be arranged at an angle in the range from 30- 60° relative to an optical axis Ax of (the radiation of) the radiation generating device. Especially, the optical axis may be defined as an imaginary line that defines the path along which light propagates through the system starting from the light generating element, here especially the radiation generating device. The Qmax may in embodiments be arranged in an angular part wherein I2=a2*lmax. In embodiments, 0.01<a2<0.7, especially 0.05<a2<0.5.

The embodiments of the system described above are especially described in relation to two angular parts of the radiation intensity (and the volumetric ion flow rate). In embodiments, the system may be divided in a plurality (especially more than two) of angular parts of the radiation intensity (and the volumetric ion flow rate). Therefore, in embodiments , the device radiation may be divided in n angular parts, each having a respective intensity I _n of the device radiation, wherein Ii>l2>. . .In, wherein the system is further configured to generate in at least part of each of the n angular parts a respective flow rate Q _n , wherein QI<Q2<. . . , Qn wherein n>3. In this way, UV radiation and ionized air may complement each other in more complex three dimensional shapes. In specific embodiments, two or more angular parts may have identical I, and two or more (other) angular parts, especially in embodiments three or more angular parts may have different radiation intensities.

When referring to n angular parts, each having an intensity I _n and a volumetric flow rate Q _n , in embodiments the intensity and volumetric flow may be averaged over the angles within the angular part.

In embodiments, the system may further comprise the control system (see also above), wherein the first volumetric ion flow rate Qi and the second volumetric ion flow rate Q2 may be selected by controlling one or more of (i) a volumetric flow rate of the ionized air, and (ii) an ion concentration of the ionized air. In embodiments, the volumetric ion flow rate may be increased by increasing an ion concentration. This may be achieved by increasing the production of ions, for instance by increase a voltage on the needle or brushes. Alternatively or additionally, in embodiments, the volumetric ion flow rate may be increased by increasing the ionized air flow rate. In embodiments, the volumetric ion flow rate may be increased by increasing the ion concentration and increasing the ionized air flow rate. In alternative embodiments, the volumetric ion flow may be decreased by decreasing the ion concentration. This may be achieved by decreasing the production of ions. In embodiments, the volumetric ion flow rate may be decreased by decreasing the ionized air flow rate. In embodiments, the volumetric ion flow rate may be decreased by decreasing the ion concentration and decreasing the ionized air flow rate.

In embodiments, the ion concentration may be defined as the number of ions per cubic centimeter. The ion concentration may be quantified using an air ion counter.

In specific embodiments, the ionized air may be divided in n angular parts each having a respective volumetric ion flow rate Q _n of the ionized air, wherein QI<Q2<. . . wherein n>3 (see also above). In embodiments, two or more angular parts may have identical Q. For instance, there may be two or more first angular parts, or two or more second angular parts, etc. Such two or more first angular parts may have the same Qi and may have the same Ii.

In embodiments, the system may be configured to generate device radiation having a first centroid wavelength Xc,i in the first angular part and a second centroid wavelength Xc,2 in the second angular part wherein Xc,i<Xc,2. Especially, in embodiments A.2 - Xc,i > 10 nm, such as at least 20 nm. Especially, in embodiments Xc,i may be selected from one of the ranges of 190-230 nm, 230-315 nm, 315-400 nm.

As some short-wavelength radiation wavelengths may be harmful to people, in particular in the UVB-range of 280-315 nm and the UVC range of 230-280 nm, they might be avoided in the first angular part and/or the second angular part, although these wavelengths may be advantageous for disinfection purposes. Therefore, more harmful wavelengths may be applied without being exposed to people. Therefore, in embodiments, in addition to the device radiation, the system may be configured to generate second radiation, which may only be used internally (i.e. such radiation may essentially not unintentionally leak from the system).

In embodiments, the system may further comprise a suction system. The suction system may be used to allow air to be filtered and/or humidified and/or temperature controlled (heated) or cooled. The suction system may be functionally coupled with a remote climate control system (such as an HVAC). The climate control system may be configured to control one or more of temperature and humidity of the air, and may optionally also filter air.

In embodiments, the suction system may also be used to expose the air within the (suction) system to the second radiation (see also above). Hence, in embodiments, the system may further comprise a suction system configured to expose air introduced in the suction system to second radiation.

In embodiments, the second radiation may comprise one or more wavelengths in the range of 190-280 nm, such as in embodiments 230-280 nm. Additionally or alternatively, the second radiation may comprise one or more wavelengths in the range of 100-200 nm. Other wavelengths, however, may also be possible.

In embodiments, second radiation may thus not be issued to the exterior from the system and may thus (essentially) not enter the angular parts.

In embodiments, the system may further comprise a light reflector, wherein the radiation generating device and the reflector may be configured such that at least part of the radiation escapes from the system via the reflector.

In embodiments, the system may comprise air outlets for issuing of ionized air. In embodiments, the system further comprises air inlets in gaseous contact with the suction system (see also above). Especially, in embodiments the air outlets may be configured to (partially) enclose the reflector. In yet further embodiments, the reflector may comprise one or more of the air inlets. Hence, in specific embodiments, the system may further comprise a suction system, configured to expose air introduced in the suction system to second radiation, wherein the second radiation has one or more wavelengths in the range of 190-280 nm region, wherein the system further comprises a light reflector, wherein the radiation generating device and the reflector are configured such that at least part of the radiation is issued from the system via the reflector, wherein the system comprises air outlets for issuing of ionized air, wherein the system further comprises air inlets in gaseous contact with the suction system, wherein the air outlets are configured to enclose the reflector, and wherein the reflector comprises one or more of the air inlets.

In embodiments, the air ionizer may create an air flow. In alternative embodiments, the air ionizer may require (or use) an air flow. In specific embodiments, an air flow may provide active cooling for the system, such as for especially cooling the radiation generating device. It may be efficient to use the air flow for cooling the system that has passed along the radiation generating device, and has thus executed its cooling function, as flow to create ions in. Hence, in embodiments the system may further comprise an air-based active cooling system, configured to cool the light generating device, wherein the air ionizer is configured to ionize air used for cooling the light generating device.

The air ionizer may comprise lamella, e.g. to direct the air flow. In specific embodiments, the position of the lamella may be controllable (e.g. rotatable and/or closable and openable).

For disinfection purposes, short- wavelength radiation may comprised by the device radiation. Dependent upon the wavelength chosen for the short- wavelength radiation, the radiation may be visible (i.e. when the wavelength is about 380 nm or larger) or may essentially be invisible to the human eye (i.e. when the wavelength is smaller than about 380 nm). In addition to one or more wavelengths from the short-wavelength range, also one or more wavelengths in a long-wavelength range may be available, wherein the long wavelength range is defined as 420-780 nm. Thus, in embodiments of the system, the device radiation may comprise one or more wavelengths selected from the range of 420-780 nm. In this way, the device radiation may thus have a color point in the visible. In specific embodiments, the device radiation has a correlated color temperature (CCT) between about 1800 K and 20000 K, and may be observed as white light for general lighting.

In specific embodiments, the radiation generating device may comprise one or more solid state light sources for generation of the device radiation, such as one or more LEDs and/or one or more laser devices.

As indicated above, the system may be used to treat air in a space and/or to irradiate a space. The term “space” may for instance relate to a (part of) hospitality area, such as a restaurant, a hotel, a clinic, or a hospital, etc.. The term “space” may also relate to (a part of) an office, a department store, a warehouse, a cinema, a church, a theatre, a library, etc. However, the term “space” also relate to (a part of) a working space in a vehicle, such as a cabin of a truck, a cabin of an air plane, a cabin of a vessel (ship), a cabin of a car, a cabin of a crane, a cabin of an engineering vehicle like a tractor, etc.. The term “space” may also relate to (a part of) a working space, such as an office, a (production) plant, a power plant (like a nuclear power plant, a gas power plant, a coal power plant, etc.), etc. For instance, the term “space” may also relate to a control room, a security room, etc.

Especially for indoor areas that are larger than the reach of a single disinfection unit, such as offices, public transport, cinema’s, restaurants, shops, etc., multiple units may be applied. Hence, in embodiments, the system may comprise a grid of a plurality of units. Such grid may be installed in a roof or ceiling. In embodiments, the individual units may be functionally connected to the control system. In embodiments, the individual units in the grid may comprise a sensor, especially one or more of a radiation sensor and an air flow sensor. In embodiments, a first individual unit may adjust its settings based on sensor signals. In embodiments, the individual units, especially the control systems thereof, may communicate with one another. The individual units may comprise means for communicating with other units, systems or devices, such as on the basis of Bluetooth, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology. In specific embodiments, settings of a first unit of the grid may depend on the settings of a second unit of the grid., wherein the settings comprise one or more of device radiation wavelength, device radiation intensity, and volumetric ion flow rate. As in embodiments general lighting and disinfection might be combined within the system, the system may be incorporated into the general lighting system of an indoor area. In specific embodiments, the system may comprise an office lighting system. In embodiments, the system may comprise a downlighter or a spotlight. In embodiments, the system may comprise a downlighter. In embodiments, the system may comprise a spotlight. The downlighter may e.g. be a luminaire. A spotlight may in embodiments also be configured as down lighter. In embodiments, the device radiation may be directed downwards, especially to the floor.

In another aspect, the invention comprises a method for treating air. In embodiments, the method may comprise exposing air to the device radiation from the system. In embodiments, the method may comprise exposing air to ionized air from the system. In embodiments, the method may comprise exposing air to the device radiation and ionized air from the system. Hence, in specific embodiments, the method for treating air may comprise exposing air to (i) the device radiation and (ii) ionized air from the system. In this way, the method may provide one or more of disinfection of pathogens, removal of particles and dust, and removal of odors. Especially, the treatment of the air may comprise disinfection of (the) air.

The embodiments described above in relation to the system of the present invention, may also apply for the method of the invention.

The lighting device may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, digital projection, or LCD backlighting.

The term “white light” herein, is known to the person skilled in the art. It especially relates to light having a correlated color temperature (CCT) between about 1800 K and 20000 K, such as between 2000 and 20000 K, especially 2700-20000 K, for general lighting especially in the range of about 2700 K and 6500 K. In embodiments, for backlighting purposes the correlated color temperature (CCT) may especially be in the range of about 7000 K and 20000 K. Yet further, in embodiments the correlated color temperature (CCT) is especially within about 15 SDCM (standard deviation of color matching) from the BBL (black body locus), especially within about 10 SDCM from the BBL, even more especially within about 5 SDCM from the BBL.

In embodiments, the CRI (coloring rendering index) of white light is larger than 75, especially larger than 80, more especially larger than 85.

The terms “visible”, “visible light” or “visible emission” and similar terms refer to light having one or more wavelengths in the range of about 380-780 nm. Herein, UV may especially refer to a wavelength selected from the range of 200-380 nm.

The terms “light” and “radiation” may thus refer to UV radiation, visible light, and IR radiation. In specific embodiments, especially for lighting applications, the terms “light” and “radiation” refer to (at least) visible light.

The term “controlling” and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein “controlling” and similar terms may e.g. refer to imposing behavior to the element (determining the behavior or supervising the running of an element), etc., such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term “controlling” and similar terms may additionally include monitoring. Hence, the term “controlling” and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element. The controlling of the element can be done with a control system, which may also be indicated as “controller”. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. In embodiments, the control system and element may not be physically coupled. Control can be done via wired and/or wireless control. The term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems. A control system may comprise or may be functionally coupled to a user interface.

The control system may also be configured to receive and execute instructions from a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or iPhone, a tablet, etc.. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

Hence, in embodiments the control system may (also) be configured to be controlled by an App on a remote device. In such embodiments the control system of the lighting system may be a slave control system or control in a slave mode. For instance, the lighting system may be identifiable with a code, especially a unique code for the respective lighting system. The control system of the lighting system may be configured to be controlled by an external control system which has access to the lighting system on the basis of knowledge (input by a user interface of with an optical sensor (e.g. QR code reader) of the (unique) code. The lighting system may also comprise means for communicating with other systems or devices, such as on the basis of Bluetooth, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.

The system, or apparatus, or device may execute an action in a “mode” or “operation mode” or “mode of operation”. Likewise, in a method an action or stage, or step may be executed in a “mode” or “operation mode” or “mode of operation” or “operational mode”. The term “mode” may also be indicated as “controlling mode”. This does not exclude that the system, or apparatus, or device may also be adapted for providing another controlling mode, or a plurality of other controlling modes. Likewise, this may not exclude that before executing the mode and/or after executing the mode one or more other modes may be executed.

However, in embodiments a control system may be available, that is adapted to provide at least the controlling mode. Would other modes be available, the choice of such modes may especially be executed via a user interface, though other options, like executing a mode in dependence of a sensor signal or a (time) scheme, may also be possible. The operation mode may in embodiments also refer to a system, or apparatus, or device, that can only operate in a single operation mode (i.e. “on”, without further tunability).

Hence, in embodiments, the control system may control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer. The term “timer” may refer to a clock and/or a predetermined time scheme.

In yet a further aspect, the invention provides a lamp or a luminaire comprising the light generating system as defined herein. The luminaire may further comprise a housing, optical elements, louvres, etc. etc... The lamp or luminaire may further comprise a housing enclosing the first light generating device, an optional second light generating device, and an optional third light generating device. The lamp or luminaire may comprise a light window in the housing or a housing opening, through which the system light may issue from the housing.

In yet a further aspect, the invention provides a system comprising a unit, wherein the unit comprises a radiation generating device, wherein the radiation generating device is configured to generate device radiation; wherein the system is configured to: generate the device radiation comprising one or more wavelengths selected from the range of 100-420 nm, wherein the device radiation has an angular dependent intensity distribution of device radiation intensity I having a maximum intensity Imax; wherein in a first angular part of the angular dependent intensity distribution a first intensity h,i of the device radiation, and wherein in a second angular part of the angular dependent intensity distribution a second intensity h,2 of the device radiation, wherein the device radiation has a first centroid wavelength Xc,i in the first angular part and a second centroid wavelength Z<.2 in the second angular part, wherein one or more of the following applies: (i) Xc,i and Ac, 2 differ, (ii) the system further comprises a control system configured to control Xc,i and Ac, 2, and I2 and h,2. Especially, controlling may be done in dependence of a sensor, user interface and/or timer (see also above). Further, in embodiments the smaller I, the smaller the centroid wavelength may be selected. Also in this way there may be compensation in space. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

Figs, la-lb schematically depict some general aspects of the system of the invention;

Figs. 2a-2b schematically depict some further aspects of embodiments of the invention;

Figs. 3a-3b schematically depict specific embodiments of the system;

Fig 4 schematically depicts a specific embodiment of the invention; and Fig 5 schematically depicts a specific embodiment of the invention. The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Figs, la and lb schematically depict some aspects of a system 1000. In the depicted embodiment of Fig. la, the system 1000 comprises a unit 1100 wherein the unit 1100 comprises a radiation generating device 100 and an air ionizer 200. The radiation generating device 100 is configured to generate device radiation 101 and the air ionizer 200 is configured to generate ionized air 201. In the depicted embodiment of Fig. lb, the unit 1100 comprises a plurality of air ionizers 200. In the depicted embodiments of Fig la-b, the system 1000 is configured to generate the device radiation 101 comprising one or more wavelengths are selected from the range of 100-420 nm. In specific embodiments, the one or more wavelengths may be selected from the range of 100-780 nm. The device radiation 101 has an angular dependent intensity distribution 110 of device radiation intensity I, having a maximum intensity Imax. In a first angular part 111 of the angular dependent intensity distribution 110, a first intensity Ii of the device radiation 101 is at least ai*I _m ax, wherein 0<ai<l, especially wherein 0.25<ai<0.75. In a second angular part 112 of the angular dependent intensity distribution 110 a second intensity L of the device radiation 101 may be smaller than ai*I _m ax. The system 1000 further is configured to generate the ionized air 201 having a first volumetric ion flow rate Qi within at least part of the first angular part 111 and a second volumetric ion flow rate Q2 within at least part of the second angular part 112. Especially Q2>QI. In embodiments of the system 1000, the device radiation 101 may be divided in n angular parts 111, 112, ... each having a respective intensity I _n of the device radiation 101, wherein Ii>l2> The system 1000 may be further configured to generate in at least part of each of the n angular parts 111, 112, ... a respective flow rate Q _n , wherein QI<Q2<. . . wherein n>3. In the specific embodiment depicted in Fig lb, the system comprises 3 angular parts 111, 112 and 113, wherein Ii>h and Ii>h and wherein Q2>QI and Qs>Qi. In embodiments, the system 1000 may be configured to generate device radiation 101 having a first centroid wavelength Xc,i in the first angular part 111 and a second centroid wavelength Xc,2 in the second angular part (112) wherein Xc,i<Xc,2. In embodiments, each angular part may have a respective centroid wavelength Xc, _n , wherein Xc,i<Xc,2<.

As depicted in the embodiment of Fig. la, the system 1000 may comprise a control system 300. The control system 300 is configured to control one or more of the radiation generating device 100 and/or the air ionizer 200 in dependence of one or more of a user interface 310, a sensor 320, and a timer.

The embodiment depicted in Fig. lb may result in a batwing shaped radiation intensity distribution. Hence, Ii>h and Ii>l3 ; I2 may be larger than I3. Hence, in embodiments QI>Q2 and Qi>Qs; Q2 may be larger than Q3.

In specific embodiments, the sensor 320 may comprise one or more of a presence sensor and a movement sensor. The control system 300 may be configured to select the one or more wavelengths in dependence of the sensor 320. Additionally or alternatively, the control system 300 may be configured to control the volumetric ion flow rate Q in dependence of the sensor 320. Additionally or alternatively, the control system 300 may be configured to control the volumetric ion flow rate Q in dependence of the device radiation intensity I. In specific embodiments, the first volumetric ion flow rate Qi and the second volumetric ion flow rate Q2 are selected by controlling one or more of (i) a volumetric flow rate of the ionized air 201, and (ii) an ion concentration of the ionized air 201.

Referring to Figs, la-lb, here cross-sectional views are shown. In a plane perpendicular to the plane of drawings (in the xy-plane), the sections 111,112 (and 113) may in embodiments e.g. be centro-symmetrical around the optical axis A _x . However, in a plane perpendicular to the drawings, they may also be elongated.

Figs. 2a-b depict the relative radiation intensity I and volumetric ion flow rate Q as they may be in the specific embodiments of Figs, la-b, respectively. In the depicted embodiments, the system 1000 may be configured to generate the ionized air 201 with the volumetric ion flow rate Q having an angular dependent volumetric ion flow rate within the second angular part 112. The volumetric ion flow rate Q may have a maximum volumetric ion flow rate Qmax; wherein the maximum volumetric ion flow rate Qmax may be provided in the second angular part 112 of the angular dependent intensity distribution 110.

Fig. 3a schematically depicts a specific embodiment of the system 1000 wherein the system 1000 further comprises a suction system 400. The suction system 400 may be configured to expose air introduced in the suction system 400 to second radiation 102. The second radiation 102 especially may have one or more wavelengths in the range of 190-280 nm, such as 230-280, though other, such as smaller, wavelengths may also be possible. Fig. 3b schematically depicts a specific embodiment of the invention, wherein the system 1000 may comprise a downlighter or spotlight. In the depicted embodiment, the device radiation 101 may be light with a correlated color temperature between 1800-20000 K. The system 1000 may further comprise a light reflector 1020, as schematically depicted in Fig. 3b. In embodiments, the radiation generating device 100 and the reflector 1020 are configured such that at least part of the radiation 101 is emitted into the exterior (environment) from the system 1000 via the reflector 1020. The system 1000 may further comprise air outlets 1030 for emission into the exterior of ionized air 201 and air inlets 410 in gaseous contact with the suction system 400. In specific embodiments, the air outlets 1030 are configured to enclose the reflector 1020 and the reflector 1020 comprises one or more of the air inlets 410.

The embodiment depicted in Fig. 3a further comprises an air-based active cooling system 500, configured to cool the light generating device 100. Especially, the air ionizer 200 may be configured to ionize air used for cooling the light generating device 100.

Fig 4 schematically depicts a specific embodiment wherein the system 1000 comprises a grid 1200 of a plurality of units 1100. This may e.g. be a bottom view from a ceiling.

Fig. 5 provides a three dimensional representation of the embodiment depicted in Fig. la. In the depicted embodiment, the unit 1100 may be incorporated in a ceiling. Device radiation 101 may be directed downwards having a maximum intensity Imax in the center of a projected area on a floor. A flow of ionized air 201 may be surrounding the Imax. For instance, Q7 ^> Q6 ^> Q5 ^> Q4 ^> Q3 ^> Q2 ^> Qi and Ii>l2>l3>l4>l5>l6>l7 The distribution of various volumetric flow rates Q7 ^> Q6 ^> Q5 ^> Q4 ^> Q3 ^> Q2 ^> Qi can easily be obtained by flow regulation means 1101 comprised in the unit 1100, for example by individual fans, valves, diaphragms, shutters, louvers associated with a respective volumetric flow rate, or for example by a single fan combined with a plurality of directional louvers or by natural convection controlled by a plurality of diaphragms. The distribution of the angular intensity distribution of device radiation can easily obtained by angular distribution means 1102 comprised in the unit 1100, for example by optical means like filters, lenses, reflectors, refractors, louvers, and/or by physical/electric means like orientation, packing density, distribution of individual light sources (like LEDs), sub-group or individual control of light sources that functions as radiation generating means.

The depicted embodiments also relate to the method of the invention for treating air, wherein the method comprises exposing air to one or more of (i) the device radiation 101 and (ii) ionized air 201 from the system 1000.

The term “plurality” refers to two or more.

The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%.

The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’.

The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species".

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.

The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.

The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Ionization may be deployed within floor standing purifiers, which utilize a fan. However, the fan results in a discomforting noise. In addition, the floor standing purifier may be an obstacle in the room. In professional spaces free-floor-standing ionizers may have the aforementioned drawbacks. Alternatively, ionizers may be integrated within the HVAC infrastructure, but this may have to be done by a highly capable professional installer as often a single HVAC air handling unit covers several rooms, resulting in a very difficult to understand airflow patterns. Air flow pattern from an HVAC air vent in a first room may change if a second room is modified e.g. by placing furniture in vicinity of the air vent. Therefore maintaining the desired HVAC air distribution within a commercial HVAC system may already be so difficult to achieve in practice that it is not advisable to add a further requirements on the HVAC air handling to ensure proper ion distribution. In addition, during longer-di stance transport of ions in an air ducts, many of the centrally produced ions are recombined and will disappear in a largely unpredictable manner, resulting in average too low/poorly controlled ion density values in occupied spaces. In addition, many occupants of spaces rent the space and have limited rights to install ionizers within the ceiling-based HVAC infrastructure, as it is controlled by the building owner. However, unlike HVAC systems, many shop owners do already install their own lighting. Thus, it may be advantageous to incorporate ionizers in a lighting system as herein proposed.

Hence, amongst others the invention proposes in embodiments a downlight for general lighting and effective disinfection using two disinfection sources i.e. UV light and air ionization. The downlight may comprise a light source for providing light source light. The light source light may be white light and/or UV light. The downlight further may comprise one or more air ionization generators for providing ionized air. The white and UV light may have a (single) peaked light distribution (as often to avoid discomfort glare in large angles) having a maximum intensity (Imax), while the air output of the ionized air velocity may have a batwing-like profile with a maximum air output velocity (Vmax) arranged on both sides of the Imax. Such a profile can be created with or without a fan and a suitable ionized air outlet(s). Such an arrangement may provide a distributed disinfection function, where the lower UV light irradiance may be compensated with higher ion density to may have a wider surface area range of disinfection when adding up the two disinfection properties of the different technologies.

In embodiments, the light distribution may have a spot shape centered around Imax and Vmax may have a ring shape. Vmax may be arranged at 0.5 to 0.05 Imax. More especially, Vmax may be arranged at 0.7 to 0.1 Imax. Vmax may be typically arranged at an angle in the range from 30 to 60 degrees. The ionized air outlet may be arranged in the rim of the downlight. The UV light may be especially safe UV light i.e. violet light (400-430 nm, such as 400-420 nm), UVA (315-400 nm) and/or far UV (190-230 nm), but in unoccupied spaces it could also be 230-315 nm. The two disinfection sources may be both on (at maximum performance) at the same time. An air inlet may be arranged in between the ionized air outlets. In this way, the UV light may be well treating the air which may be sucked into the downlight. The air inlet may be arranged in a reflector of the downlight. Air in the downlight may be treated with a photo catalytic layer and (an additional) UV light. The downlight may also comprise a presence sensor. In case non-safe UV light may be used, it may be switched off when a person may be detected by the sensor. In the latter case, Vmax may be increased. The ionizer and UV might also be used in a sequential mode.