Improved photobiological treatment device

Abstract

A photobiological treatment device (1) is described, comprising: at least one light-emitting diode (10); a supervisor (40) adapted to receive a set of parameters relating to periodic light signals to be emitted, and to generate at least one periodic control signal conforming to the set of parameters received, said set of parameters comprising at least: a maximum power of the periodic light signals to be emitted, less than 100 W / m², a frequency of the periodic light signals to be emitted, a duty cycle of said signals, and a duration of the treatment phase during which the signals are emitted; and a power supply circuit (50) for the light-emitting diode, adapted to receive the control signal generated by the supervisor, to generate a periodic current identical to the received control signal, and to supply said light-emitting diode with the generated current. Abstract figure: Figure 1

Description

Title of the invention: Improved photobiological treatment device technical field

[0001] This disclosure falls within the field of photobiological treatment, that is, the treatment of biological organisms using light signals. It has particular applications in the areas of decontamination, food preservation, and the improvement of the nutritional, organoleptic, and sanitary qualities of foodstuffs in a sustainable manner that respects human health, the planet, and the animal world. Prior art

[0002] It has been known for many years to use the properties of light for decontamination applications, for example, of water. For this purpose, mercury vapor lamps producing continuous UV light with a wavelength of 253.7 nm have long been used. Xenon flash lamps emitting short flashes covering the entire light spectrum have also been used.

[0003] The disadvantages of using this type of lamp are numerous. First, these lamps are not environmentally friendly because they consume a very large amount of electricity and take a long time to light up because they need to reach a certain temperature to operate. Mercury vapor lamps have the additional disadvantage of containing mercury, which is harmful to the environment. These lamps are therefore incompatible with ecodesign requirements and, moreover, will probably be banned from sale in the near future.

[0004] Furthermore, it is also known that plants possess photoreceptors sensitive to different wavelengths, and research is currently exploring the possibilities of using these wavelengths to specifically stimulate certain photoreceptors and thus trigger mechanisms to improve certain properties of treated plants. Examples include the article by L. Huché-Thélier et al., “Light signaling and plant responses to blue and UV-radiations - Perspectives for applications in horticulture”, Environmental and Experimental Botany, Elsevier, 2016, 121, pp. 22-38. 10.1016 / j.envexpbot.2015.06.009. hal-01388732, and the article by S. Eichhorn Bilodeau et al., “An update on Plant Photobiology and Implications for Cannabis Production”, 2019, Front. Plant Sci. 10:296 doi:10.3389 / fpls.2019.00296.

[0005] These publications highlight the diversity of biological mechanisms impacted by light, as well as the diversity of photoreceptors involved and the wavelengths to which these photoreceptors are sensitive. However, the mercury vapor lamps or xenon flash lamps mentioned earlier are not suitable for this type of application. On the one hand, they generate a significant amount of heat in the same direction as the light beam, which reduces their potential for use in treating live plants sensitive to thermal and electromagnetic radiation.

[0006] Moreover, the high light power generated by these lamps is likely to quickly saturate the photosensors of plants, which induces counterproductive stress in the plant, and thus limits the use beyond simple surface decontamination without degrading the corresponding foodstuffs.

[0007] Finally, these lamps impose a single mode of operation (continuous illumination for mercury vapor lamps, flashes for xenon flash lamps), which severely limits the diversity of photobiological treatments as well as the treatment targets. For xenon flash lamps, the fact that these lamps cover the entire visible spectrum raises the risk of emitting stray wavelengths that disrupt the desired treatment. To overcome this drawback, optical filters can be used to filter certain wavelengths, but this implies overconsumption of energy relative to the intended purpose, and therefore a negative environmental impact.

[0008] In view of these significant limitations, developments have been undertaken to replace these technologies with light-emitting diodes (LEDs), which offer the advantage of reduced power consumption and less heating of the matrix being treated, since LEDs dissipate heat in the opposite direction to the emission of photons. For example, document WO 2014 / 036083 describes a food storage device such as a refrigerator, comprising means for decontaminating stored foodstuffs, these means including UV sources which may be LEDs, and a control device capable of operating the UV sources in different modes such as a sterilization mode and a food preservation mode.

[0009] However, to obtain the expected results of a photobiological treatment, it is necessary to precisely control the power and quantity of energy received by the treatment target, and therefore to precisely control the light sources. This is confirmed, for example, by document WO 2018 / 167439, which describes a food decontamination process comprising exposing the food to light pulses in the UV range, the pulses having a duration of between 50 ps and 2 s, with an energy density of between 0.1 kJ / m2 and 3 kJ / m2.

[0010] However, these documents do not describe a device for achieving this level of precision in controlling light sources, even when it comes to light-emitting diodes. Summary

[0011] A photobiological treatment device is proposed, comprising: - at least one light-emitting diode; - a supervisor, adapted to receive a set of parameters relating to periodic light signals to be emitted, and to generate at least one periodic control signal conforming to the set of parameters received, said set of parameters comprising at least: • a maximum power of the periodic light signals to be emitted, said maximum power being less than 100 W / m2, preferably less than 30 W / m2, • a frequency of the periodic light signals to be emitted, • a duty cycle of said signals, and • the duration of emission of the light signals, and - a power supply circuit for the light-emitting diode, adapted to receive the control signal generated by the supervisor, to generate a periodic current identical to the received control signal, and to supply said light-emitting diode with the generated current.

[0012] According to another aspect, a photobiological treatment device is proposed comprising: - a cavity in which a target to be treated can be positioned, - at least one cavity lighting module, each lighting module comprising at least one light-emitting diode and a power supply circuit for the diode(s) of the lighting module; and - a supervisor, adapted to receive at least one set of parameters relating to periodic light signals to be emitted, and to generate and transmit to each lighting module a control signal determined from the parameters received, Each lighting module is adapted to receive a control signal generated by the supervisor, to generate a current identical to the received control signal, and to power said light-emitting diode with the generated current. and in which each lighting module is removably mounted in the photobiological processing device.

[0013] In embodiments of this second aspect, the parameters may include one or more of the following parameters: a maximum power of the periodic light signals to be emitted, said maximum power being less than 100 W / m2, preferably less than 30 W / m2, • a frequency of the periodic light signals to be emitted, • a duty cycle of said signals, and • the duration of emission of the light signals, and

[0014] The devices described above may also have one or more of the following characteristics, taken alone or in combination.

[0015] In embodiments, the device includes at least one light-emitting diode emitting in a wavelength range between 260 and 310 nm.

[0016] In embodiments, the device comprises at least two diodes, and the supervisor is adapted to generate at least two different control signals relating to at least two diodes.

[0017] In embodiments, the parameter set further includes at least one of the following additional parameters: - a delay in the start-up of the emission of light signals by a diode or group of diodes relative to an initial reference time, - a number of repetitions of a processing phase, where a processing phase corresponds to the total time during which light signals are emitted by at least one diode or group of diodes, and - a time interval between two consecutive processing phases.

[0018] In some embodiments, the device further comprises a temperature sensor adapted to measure at least one temperature from the following group: - a temperature in the vicinity of at least one light-emitting diode, - a temperature in the vicinity of a heat sink of a diode or a group of diodes, - a supervisor temperature, - a temperature in the vicinity of the target to be treated, and the supervisor is configured to receive the temperature measurement and to modify the duty cycle of the control signal and lengthen the duration of the treatment phase when the measured temperature exceeds a predetermined threshold.

[0019] In embodiments, the supervisor is configured to modify the control signal in real time according to an ambient temperature, a temperature measured in the vicinity of a diode, and a distance between a diode and the target, so that the light signals emitted by the diodes bring a determined energy level to the target.

[0020] In embodiments, the device comprises a plurality of light-emitting diodes arranged in a plurality of parallel rows, wherein the spacing between two consecutive diodes in a row and the spacing between two consecutive rows are determined such that the fluence emitted at the level of a plane parallel to the plane of the diodes and located at a determined distance between the diodes and the target is homogeneous.

[0021] In embodiments, the device further includes a memory storing, for a set of processing, a set of parameters relating to the light signals to be emitted, and / or a Human-Machine interface adapted to receive a set of parameters relating to the light signals to be emitted from an operator.

[0022] In embodiments, each light-emitting diode emits in a wavelength range between 200 and 800 nm.

[0023] In some embodiments, the device is adapted to emit light signals with a frequency between 0 and 10000 Hz, for example between 2 and 100 Hz.

[0024] In embodiments, each LED power supply circuit includes at least one metal-oxide gate field-effect transistor and a DC current source connected to the transistor source, the control signal generated by the supervisor being connected to the transistor gate.

[0025] In embodiments, the device includes a cavity in which a target to be treated can be placed for the implementation of the treatment, and means for measuring and adjusting the distance between the light-emitting diode and the target to be treated.

[0026] In embodiments, the device includes at least one lighting module comprising at least one diode and a diode power supply circuit, the lighting module further comprising a heat sink suitable for dissipating the heat generated by the diode(s).

[0027] In embodiments, the device comprises a housing formed by a set of walls, the housing comprising a cavity in which a target to be treated can be placed, and a compartment adjacent to the cavity, housing said supervisor and each lighting module, in which each lighting module is removably mounted in the compartment.

[0028] In embodiments, the housing includes a front or side wall having an access window to the compartment housing each lighting module, said access window being dimensioned to allow the insertion and removal of a lighting module through the window, and the compartment and each lighting module include mechanical connectors adapted to allow the mounting and dismounting of a lighting module through the window.

[0029] In embodiments, the device may include a partition wall separating the compartment and the cavity, said partition wall comprising a through-opening, and each lighting module is adapted to be mounted in the compartment so that each diode illuminates the interior of the cavity through the through opening.

[0030] In embodiments, the compartment includes at least one pin or centering hole for a lighting module and at least one bolt for fixing said module to the compartment.

[0031] In embodiments, the mechanical connectors of the compartment include centering members and locking members, arranged respectively on two opposite sides of the through opening, the centering members being located on the side of the through opening opposite the access window, and the locking members being located on the side of the access window.

[0032] In embodiments, the compartment includes a projecting stop for the lighting modules, the stop being disposed on an edge of the through opening of the partition wall opposite the access window.

[0033] In embodiments, the centering members include centering pins arranged on the stop.

[0034] In embodiments, the locking members include at least one bolt mounted on the separating wall.

[0035] The photobiological treatment device described above allows for a wide variety of photobiological treatments to be performed on diverse targets with high precision. Indeed, it enables the real-time control of a light-emitting diode or a group of diodes to generate periodic light signals corresponding to desired parameters in terms of frequency, signal duration, interval between signals, etc. It is also possible to combine several diodes of different wavelengths, from UV to infrared, to combine desired effects on a target and thus perform highly targeted treatments adapted to each type of target.

[0036] The use of short-duration light signals emitted by light-emitting diodes also makes it possible to limit the light intensity (irradiance) to which the target is subjected, thus preventing saturation of the plant's photoreceptors. Controlling the parameters of the periodic light signals also allows control of the target's exposure time to light and therefore also of the light energy (fluence) received. This makes it possible, particularly in the case of plants and foodstuffs, to carry out effective treatment without degrading the treated targets.

[0037] In some embodiments, the use of diodes, active or passive heat dissipation systems, and / or adjustment of the parameters of the emitted light signals based on the temperature measured at the LEDs, heat sinks, the LED power supply circuit, and in the vicinity of the targets, makes it possible to control the emitted light signal in real time to ensure optimal target processing and maximum diode lifespan. Regulating the temperature The diodes' operating temperature allows them to function in their optimal efficiency zone, thus extending their lifespan, in line with sustainable development principles. Brief description of the drawings

[0038] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which: Fig. 1

[0039] [Fig.l] represents a schematic diagram of a photobiological treatment device according to one embodiment. Fig. 2

[0040] [Fig.2] represents an example of a photo-biological processing device. Fig. 3

[0041] [Fig.3] represents an example of a control signal generated by a photo-biological processing device for a set of light-emitting diodes. Fig. 4

[0042] [Fig.4] represents an example of a lighting module of a photo-biological treatment device according to one embodiment. Fig. 5a

[0043] [Fig.5a] is a schematic top view representation of a lighting module. Fig. 5b

[0044] [Fig.5a] is a schematic side view representation of the lighting module of [Fig.5a]. Fig. 6

[0045] [Fig.6] represents an example of mounting a lighting module in a photobiological treatment device according to one embodiment. Fig. 7

[0046] [Fig.7] represents a compartment of a photobiological processing device, the compartment housing a supervisor and a lighting module. Fig. 8

[0047] [Fig.8] schematically represents irradiance levels compared between the device according to one embodiment, a mercury vapor lamp and a Xenon flash lamp. Description of the implementation methods

[0048] With reference to Figures 1 and 2, we will now describe a photobiological treatment device 1. This device 1 can be used for decontamination or sterilization applications, preservation of foodstuffs, plants or seeds, or in the improvement of the nutritional, organoleptic, and sanitary qualities of foodstuffs, plants or seeds.

[0049] The photobiological treatment device 1 can be used on a treatment target which may be a solid foodstuff, for example harvested fruits and vegetables, or meat or fish, or a liquid, such as water, milk, fruit juice or honey. This device can also be used on targets that can be used in agriculture, such as seeds or seedlings, harvested or cultivated flowers, plants grown in soil, etc.

[0050] The device 1 comprises at least one light-emitting diode 10, and preferably a plurality of light-emitting diodes 10. In the case where the device comprises several diodes, these may emit light of the same wavelength or of several different wavelengths. For example, the device may comprise several sets 11 of diodes of respective wavelengths, each set comprising one or more diodes.

[0051] In order to implement treatments adapted to various targets, the device 1 includes a control circuit 2 described below, which is configured to control the emission, by the light-emitting diodes 10, of precisely controlled periodic light signals so as not to exceed a maximum irradiance on the target, i.e., the surface density of energy flux received by the target, expressed in W / m², but also to very precisely control the parameters of the emitted light signals, so as to also control the fluence, i.e., the total light energy received by the target. The device 1 typically makes it possible to maintain the irradiance on the treated target low, i.e., less than 100 W / m², typically less than 50 W / m², or even less than 30 W / m², in order not to saturate the plant photoreceptors and thus to maximize the effects of the photoreceptor emission. With reference to [Fig.[8] A schematic representation shows a comparative irradiance level between the device according to the invention, a mercury vapor lamp, and a xenon flash lamp. A mercury vapor lamp produces continuous light, and therefore irradiance, on the order of 10,000 W / m², while a xenon flash lamp emits flashes of very high irradiance (on the order of MW / m²) for a very short duration, with time intervals of approximately 1 to 2 seconds between two flashes. The device described below allows, through the use and precise control of light-emitting diodes, the generation of periodic light signals with an irradiance level strictly less than 100 W / m².

[0052] In some embodiments, the periodic light signals are pulses, and the control circuit is adapted to control the duration during which the periodic light signals are emitted, as well as the frequency and duty cycle of the pulses. In the case where the device 1 comprises several diodes 10 of lengths Given different wavelengths, each diode or group of diodes of the same wavelength can be controlled to emit light signals with respective parameters. A group of diodes comprising diodes of several different wavelengths can also be controlled to emit light signals according to a first set of parameters, and another group of diodes can be controlled according to a second set of parameters. In these cases, the parameters defining the light signals to be emitted may include a signal emission duration (d), a frequency, and a duty cycle of the pulses, which can be specific to each diode or group of diodes.

[0053] In the case where the device comprises several sets of diodes 10 controlled according to different parameters, the total duration of a processing phase comprising the control of several groups of diodes to generate a light signal with a respective emission duration is denoted in the following by T. The start of the light emission by one group of diodes may be offset relative to another group of diodes, so that the total duration T of a processing phase may exceed the maximum emission duration of the light signals from all the groups of diodes. Consequently, the parameters defining the light signals emitted respectively by several diodes or sets of diodes may also include at least one of the following additional parameters: - a delay in the start of the emission of light signals relative to the start of the processing phase, - a number of repetitions of the treatment phase, corresponding to a total treatment duration, - a time interval between two consecutive treatment phases.

[0054] Thus, during a processing phase, not all diodes are controlled to generate light signals at the same time and the duration of emission of periodic light signals by a diode or a set of diodes may be shorter than the duration of the processing phase.

[0055] Furthermore, repeating treatment phases, possibly with a time interval between two consecutive treatment phases, allows for the automation of a treatment process in which the phases can be repeated at regular time intervals, for example, daily, weekly, etc. Device 1 is therefore configured to allow the emission of fully controlled periodic light signals, in one or more wavelengths, with low irradiance. Modulating the light signals (periodic signals) increases the efficiency of the treatments implemented while controlling the exposure time of the target to the light signals, and therefore the total fluence received at the target.

[0056] Each light-emitting diode 10 of the device 1 is adapted to emit light light with a wavelength between 200 and 800 nm. In some embodiments, the device 1 includes at least one diode 10 or a set of diodes adapted to emit light in a wavelength range between 260 and 310 nm. This wavelength range corresponds to a maximum sensitivity range of the plant UVR8 photoreceptor, which impacts the nutritional properties and resistance to pathogens of the plants. The device 1 may further include at least one additional diode 10 or a set of additional diodes in a different wavelength range, for example in the visible spectrum.

[0057] By way of non-limiting example, the device 1 may include one or more diodes 10 in the UVC range, for example at 270 nm, one or more diodes 10 in the non-UVC UV range, one or more diodes 10 in the visible range, and one or more diodes 10 in the infrared range. The precise selection of illumination wavelengths, through the selection of the diodes 10, and the control of the modulation of the light signals and the energy received by the target, makes it possible to send precise signals to the photoreceptors of plants involved in regulating phenomena such as germination, vegetative and root growth, flowering, and coloration. This allows, for harvested plants, the preservation of the plants and an increase in their organoleptic and nutritional properties, and for cultivated plants, the improvement of crop yield and resistance to diseases and pests.Controlling the emitted light signals, and therefore the energy received by the targets, makes it possible to trigger biological processes without saturation or harmful stress.

[0058] The frequency of the periodic light signals emitted by the diode(s) 10 is between 1 and 1000 Hz, preferably between 2 and 100 Hz. These low frequencies allow for better efficiency of the photo-biological treatments implemented.

[0059] Furthermore, in the case where the device 1 comprises several light-emitting diodes 10, the diodes are advantageously arranged so as to provide the target with a homogeneous fluence. According to Lambert's law, the luminous intensity I of an orthotropic source is expressed as a function of the luminous intensity along the axis normal to the illumination surface and the angle α with respect to this normal according to the following law: I(α) = α / (θ) cos(α)

[0060] This is applicable to light-emitting diodes, and consequently, for an angle α of 60°, the luminous intensity is equal to 50% of the luminous intensity at the normal. To obtain a homogeneous fluence at the target, the diodes are therefore advantageously arranged in a plurality of parallel rows, with a constant pitch between two consecutive diodes in the same row and a constant pitch between two diodes in two consecutive rows, these pitches being chosen from in order to optimize the normal fluence value at any point in a plane parallel to the plane in which the diodes are arranged.

[0061] Denoting P as the pitch between two consecutive diodes, and D as the distance between the diodes and the plane considered, we obtain a homogeneous fluence with the following relation: g = 2tan 60 0

[0062] For a target positioned at a distance D, the light intensity received at the normal to a diode or at half the spacing between two consecutive diodes is the same. For example, for a linear strip of diodes with a spacing of 4 cm, the distance is 1.16 cm. It should be noted that this proximity is possible with diodes that do not emit heat in the direction of radiation, but in the opposite direction. Furthermore, beyond this distance, the entire set of diodes can be considered a uniform source.

[0063] We can use Keith's irradiance formula: Σ — P 4- sin Where E is the irradiance measured at the detector (W / m2), P is the power of the diode (W), L is the length of the diode (m), D is the distance between the diode and the detector (m) and a = arctan is half the angle of the diode's field of view in radians. At this In this regard, a light-emitting diode offers a (planar) illumination angle of 120°.

[0064] In some embodiments, the device 1 includes a Human-Machine Interface 20 and / or a memory 30 that allow the parameters of the light signals to be emitted to be selected. A memory 30 can indeed store a database in which, for each of a set of different treatments, the parameters of the light signals to be emitted for the implementation of that treatment are recorded. A database can concern treatments associated with a set of foodstuffs, and for each foodstuff, sets of parameters associated with different types of treatments. According to a purely illustrative example, the database can store parameters for different treatments specifically adapted to tomatoes, for example: decontamination, preservation (i.e.(increased shelf life), and parameters for different treatments specifically adapted to carrots, for example: decontamination, preservation, and improvement of nutritional properties.

[0065] In the case of a Human-Machine Interface 20, this may include, for example, display means, such as a screen with a graphical interface, and data input means, such as a keyboard and / or a mouse and / or a touchscreen, allowing an operator to manually enter the parameters of the light signals to be emitted for each set of diodes 10, and to initiate a process. The Human-Machine Interface 30 may also be coupled to memory 30, so as to allow an operator to select a set of parameters pre-recorded in memory 30 and corresponding to a particular type of use of the photo-biological device.

[0066] Once a process is initiated, it is advantageously implemented in real time. The Human-Machine Interface 30 can be configured to display, during the implementation of the process, one or more of the following pieces of information: the start time of the process, the total processing time, the time elapsed since the start of the process, the time remaining before the end of the process.

[0067] The Human Machine interface 30 can also allow saving a set of parameters for later reuse, and also recording and / or viewing a set of treatments implemented with the device.

[0068] The memory 30 can be local or can be a remote server which can be accessed via a telecommunications network.

[0069] In embodiments, as shown for example in [Fig.2], the photobiological treatment device 1 may include a fixed or mobile housing 100 containing the light-emitting diodes 10 and the diode control circuit 2 described below, and a computer 200 connected to the housing, either wired or wirelessly, the computer including the Human-Machine interface 20, optionally the memory 30 and a calculator (not shown) allowing the parameters from the memory or the Human-Machine interface to be communicated to the control circuit.Alternatively, the photobiological treatment device 1 can be fully integrated, i.e., include a housing 100 containing the diodes 10, the diode control circuit 2, and a Human Machine interface 20, for example a touch screen, mounted on the housing and allowing an operator to enter parameters of light signals to be emitted or to select, from a memory also stored in the housing or accessible remotely, pre-recorded parameters.

[0070] The diode control circuit 2 of device 1 includes a DC power supply (not shown), which may be a battery or an AC / DC converter connected to the mains. For example, the DC supply voltage of device 1 may be 48V. The fact that device 1 uses a DC power supply significantly limits the generated electromagnetic fields, which is healthier for the operator and also advantageous in applications involving living plants, since electromagnetic fields can saturate certain photoreceptors.

[0071] The control circuit 2 further includes a supervisor 40, for example a processor, a microprocessor, or a microcontroller, which is adapted to receive all the parameters relating to the periodic light signals to be emitted by the or the diodes 10, and to generate a periodic control signal, in the form of constant amplitude voltage pulses, whose parameters are identical to all the received parameters. The parameters received by the supervisor 40 therefore define both the light signals to be emitted by the diode(s), and the control signal(s) generated by the supervisor 40.

[0072] Therefore, the control signal generated by the supervisor 40 for a diode 10 or a set 11 of diodes comprises a set of voltage squares, defined by the following parameters: - A duration d during which the voltage pulses are generated, which corresponds to the duration d of emission of the light signals for the diode(s) considered, - A frequency f of the voltage pulses, which corresponds to the frequency f of the pulses of the light signal to be emitted, and - A duty cycle T of the voltage squares, corresponding to the duty cycle T of the squares of the light signal to be emitted.

[0073] In embodiments where different light signals are to be emitted by at least two diodes or two sets of diodes, the supervisor 20 can generate a control signal for each set of diodes according to the parameters mentioned above, wherein the pulse generation time d, the frequency f, and the duty cycle are specific to each control signal generated for a respective set of diodes. Furthermore, the parameters defining the control signals can also include at least one of the following additional parameters: - a delay in the start of the emission of light signals relative to the start of the processing phase, i.e., a delay in the first voltage pulse relative to the start of the processing phase, - a number of repetitions of a treatment phase, corresponding to a total treatment duration, and - a time interval between two consecutive treatment phases.

[0074] With reference to Figure 3, an example of a set of control signals generated by the supervisor for a process involving three sets of light-emitting diodes is shown. The control signals associated with each set of diodes 10 are labeled LED1, LED2, and LED3 in the figure. For all three sets of LEDs, the duration T of the processing phase is common. A processing phase can, for example, last between 10 seconds and 1 hour, and can be repeated so that a complete processing can last several days or even several weeks. Each group is also associated with a frequency f; pulses (we have re The period T is shown in Figure 3, and f = 1 / T, along with a duty cycle T of the pulses. Furthermore, in the example shown, the control signal associated with the first group of LEDs (LED1) starts at the beginning of the processing phase but has a shorter emission duration (di) than the processing phase. The two other control signals associated with the other two groups of LEDs (LED2, LED3) have a delay (t2, t3) relative to the start of the processing phase, but these signals last until the end of the phase. In another example, they could also terminate before the end of the processing phase.

[0075] For each control signal, the amplitude of the voltage pulses is fixed. For example, the amplitude of the voltage pulses may be a few volts.

[0076] Returning to [Fig. 1], the photobiological treatment device 1 also includes a power supply circuit 50 for the light-emitting diode 10, or for a set 11 of diodes, adapted to receive a control signal generated by the supervisor 40, to convert the control signal into current, i.e., to generate a periodic current proportional to the received control signal, and to supply said diode or set of diodes with the generated current. The current generated by the power supply circuit 50 has the same parameters (frequency, emission duration, duty cycle of the pulses) as the control signal; only the pulse amplitude may differ from the pulse amplitude of the control signal.

[0077] This direct conversion of a control signal to a diode supply current allows for precise control of the diodes' switching on and off. Switching on corresponds to phases where the control signal pulses are high, and switching off corresponds to phases where the control signal pulses are low (0), since the diodes are no longer receiving current in this case. Furthermore, the number of photons emitted by a diode is proportional to the intensity of the received current; therefore, the light energy emitted by the diodes supplied by this current is proportional to the duty cycle of the resulting supply current pulses. A duty cycle of 1 corresponds to a continuous current and maximum diode energy, while a duty cycle of 50% corresponds to a diode light energy equal to half the maximum energy.

[0078] In some embodiments, the power supply circuit 50 comprises at least one metal-oxide-semiconductor field-effect transistor (MOSFET) and a DC current source connected to the transistor's source, with the control signal received from the supervisor being connected to the transistor's gate. In this way, when the control signal pulses are at their maximum amplitude, the transistor becomes conductive and the current generated by the current source is supplied to the diodes. When the pulses When the control signal is at zero, the transistor acts like an open switch, no current reaches the diodes and they turn off.

[0079] The device may also include several power supply circuits 50 adapted to each power a set of diodes comprising several diodes of the same or different wavelengths. In this case, each power supply circuit 50 receives a respective control signal generated by the supervisor 40, and generates an identical supply current for all the diodes served by the power supply circuit 50. The use of several power supply circuits 50 receiving respective control signals thus makes it possible to drive several sets of diodes 10 differently.

[0080] The control circuit 2 described above allows real-time control of the light-emitting diodes 10 by the supervisor 40, which also allows certain parameters to be adjusted in real time. In particular, the photobiological treatment device 1 may include one or more temperature sensors 60, adapted to measure a temperature at at least one of the following locations: - at the level of at least one light-emitting diode, - at the level of a heat sink of at least one light-emitting diode nescente, examples of heat sinks are described in more detail below, - in the vicinity of the target to be treated, - at the level of the supervisor. The temperature sensor(s) 60 are also connected to the supervisor in order to be able to transmit this / these temperature(s) to it.

[0081] In one embodiment, the device 1 may include a temperature sensor adapted to measure the temperature on a heat sink placed on the back face of a diode or a group of diodes, since this is the side on which heat is generated by a diode. In one embodiment, several light-emitting diodes may be mounted on a support, typically a printed circuit board, placed at regular intervals, and a temperature sensor may be mounted on the same support between two consecutive diodes. For measuring a temperature in the vicinity of the target, the device 1 may include a housing 100 defining a cavity 110 in which a target to be treated may be positioned, and one or more temperature sensors may be placed in the cavity. Alternatively, a temperature sensor may be placed between a diode and the target to be treated.

[0082] The supervisor 40 can also be configured to modify the control signal in real time according to the measured temperature in order to prevent overheating of the target being treated and of the diodes. In one embodiment, when the temperature measured in the vicinity of the diodes and / or the target exceeds a threshold Once determined, the supervisor is configured to modify the duty cycle, specifically to decrease the duty cycle of the control signal pulses and to lengthen the respective emission durations of each diode or group of diodes. Indeed, decreasing the duty cycle reduces the light output and therefore the heat generation, while lengthening the phase duration compensates for this power reduction to maintain the same energy level. In this way, the supervisor can generate control signals that are temperature-dependent, as measured near the diodes, to limit heating of both the target and the diodes, while maintaining the same total light energy received by the target.

[0083] Regulating the temperature according to the temperature of the target prevents excessive heat from damaging the target being treated. Regulating the temperature according to the temperature of the diodes ensures that the diodes always operate within their maximum efficiency range and limits their aging. This guarantees maximum diode service life by preventing premature aging.

[0084] The Human Machine interface 20 can then be configured to display the temperature measured by each temperature sensor 60. It can also be configured to display a message or an icon informing that the control signal parameters have been changed in view of a measured temperature.

[0085] In some embodiments, the photobiological treatment device 1 may also include a distance sensor 70 between the diode(s) and the target, and the supervisor 40 may be configured to modify each control signal in real time according to the distance between the diode and the target, so that the energy level received by the target is always equal to a predetermined energy level. The control signal may also be adapted according to the ambient temperature and the temperature measured in the vicinity of a diode, as described above.

[0086] Furthermore, in certain embodiments, the device 1 may include means 71 for adjusting the distance between the diode(s) and the target. This may be, for example, a support positioned under the target and having an adjustable height. The distance between the diode(s) and the target is advantageously displayed by the Human-Machine Interface.

[0087] With reference to Figures 4, 5a and 5b, in some embodiments, the photobiological treatment device 1 comprises at least one, and preferably a plurality of lighting modules 90, each lighting module comprising a set of light-emitting diodes 10 and a power supply circuit 50 for this set of diodes. The lighting module may include a mechanical support for the diodes, for example a printed circuit board 91, which also provides the electrical connection of the diodes to the power supply circuit 50.

[0088] In some embodiments, each lighting module 90 further includes a heat sink 92 adapted to dissipate the heat generated by the diode(s). The heat sink may be active or passive. For example, the heat sink 92 may comprise a set of cooling fins arranged parallel to each other on a rear face of the printed circuit board bearing the diodes, i.e., on the side opposite the side where the diodes emit light, since this is the side where the diodes emit the most heat. Each lighting module may also include a temperature sensor, this sensor being, for example, inserted between two consecutive diodes or between two rows of diodes in the module or in the heat sink, allowing the temperature in the vicinity of the diodes to be measured.

[0089] The power supply circuit 50 for the diodes 10 of the lighting module 90 is connected to the supervisor 40, and is configured to receive a control signal for all the diodes 10 of the lighting module, whether they have the same wavelength or not.

[0090] In addition, each lighting module 90 is advantageously configured to be removable relative to the rest of the processing device 1.

[0091] In this way, the photo-biological treatment device 1 is modular and it is possible to easily replace one lighting module with another, comprising a set of different diodes, in order to implement different treatments.

[0092] With reference to Figures 2, 6 and 7, a particular embodiment of the integration of a lighting module 90 into a processing device 1 is shown. This embodiment is suitable for processing harvested fruits or vegetables, seeds or harvested flowers.

[0093] The treatment device 1 comprises a housing 100 formed by a set of walls 120, the housing comprising a cavity 110 in which a target to be treated can be placed, and a compartment 130 adjacent to the cavity, housing the supervisor 40 and capable of housing a plurality of lighting modules 90. The walls of the housing can be perforated in order to ensure ventilation of the air contained in the compartment and thus the cooling of the latter.

[0094] Each lighting module 90 is removably mounted in the compartment 130 and, in this respect, includes removable mechanical connection means 93, 94 for attaching or removing a lighting module 90 from the compartment 130, and also removable electrical connection means (not shown) for connecting or disconnecting the lighting module 90 from the supervisor. The housing 100 also includes removable mechanical connection means 103, 104 adapted to cooperate with those of each lighting module. The connector also includes (removable) electrical connection means for connecting or Disconnecting the lighting module 90.

[0095] In the example shown in Figures 2 and 7, the housing 100 can be substantially parallelepiped in shape, with the cavity 110 and the compartment 130 also being parallelepiped. The compartment can be positioned above the cavity 110, which receives the target to be treated, and separated from this cavity by a partition wall 140 comprising a through-hole 141 adapted to allow the light emitted by the diodes to pass towards the target.

[0096] The through-opening 141 can, for example, be formed of a grid so as to allow light to pass through while forming a mechanical support for the lighting modules 90. Alternatively, and as shown in [Fig. 7], the through-opening 141 can comprise a single, continuous opening arranged in the partition wall 140, which is dimensioned so that each lighting module 90 can rest on two opposite edges of the through-opening, or that it can be held suspended above the through-opening by the mechanical connection means of the housing. According to yet another variant shown schematically in [Fig.[2], the through opening may include several adjacent openings, one for each lighting module, each opening being separated from an adjacent opening by a strip 142 allowing both to delimit locations for the lighting modules and optionally to form a support for the modules.

[0097] In one embodiment, the housing 100 is configured to allow easy access to the lighting modules 90, as well as simple mounting and dismounting of these modules. For example, a wall 121 of the housing 100, advantageously a front or side wall, i.e., the wall of the housing facing the operator, may include an access window 122 sized to allow the insertion and removal of a lighting module through the access window. Advantageously, the access window is also sized so that an operator can pass one or both arms through it. This access window is advantageously closable with a door to prevent dust from settling in the compartment. For example, an opening providing access to the cavity for placing the target to be treated and the access window to the compartment 130 may be arranged in the same wall of the housing.

[0098] Furthermore, compartment 130 of the housing 100 and each lighting module 90 include mechanical connectors 103, 104 that allow the lighting module to be mounted and removed through the access window 122. In the embodiment shown in Figures 6 and 7, the mechanical connectors 103, 104 of compartment 130 are supported by the partition wall 140 and are arranged on either side of the through opening 141 in a direction extending from the window access 122 to the compartment wall opposite the wall 121 in which the access window is located. To limit manipulations to an area near the access window, the mechanical connectors may, for example, include centering elements 103 located at the edge of the through-opening 141 furthest from the access window. These centering elements may include, for example, one or more projecting centering pins that can be fitted into one or more additional bores 93 provided on a lighting module, or vice versa. The mechanical connectors may also include locking elements 104, located near the edge of the through-opening closest to the access window.These locking mechanisms may, for example, include a bolt 104 carried by a wall, for example the partition wall, which an operator engages in an opening 94 provided for this purpose on the lighting module.

[0099] The housing 100 may also include a stop 105 disposed on the partition wall at the edge of the through-opening furthest from the access window, or on the wall opposite the access window. The centering elements 103 of the housing may be mounted on said stop 105, as is the case in [Fig. 7] where the centering pins extend projecting from the stop towards the access window.

[0100] In this embodiment, each lighting module 90 has the shape of a parallelepiped extending along a principal direction. Each lighting module comprises, successively along this principal direction, a housing 95 containing the power supply circuit 50 for the diodes 10, and then the printed circuit board 91 on which one or two rows of diodes 10 are mounted, behind which is the heat sink 92. The centering member 93 carried by the lighting module may be located at the opposite end of the lighting module from the housing 95 containing the power supply circuit, and the locking member 94 may be located at the end of the lighting module corresponding to the housing containing the power supply circuit.In this way, an operator can insert a lighting module 90 through the access window of the housing 100, first inserting the end of the module with the centering element 93 until this end reaches the stop and the centering elements 93 of the module cooperate with those 103 of the housing. Then, the operator can place the other end of the module on the partition wall at the edge of the through-opening adjacent to the access window, and lock the module using the latch 104 provided for this purpose. Since the diode's power supply circuit 50 is located on the side of the access window, its electrical connection to the supervisor is facilitated 40. The operator can then close the access window 122.

[0101] In one embodiment, a photobiological treatment device according to the preceding description is made with three lighting modules comprising 250 LEDs arranged in six rows provide an emission surface area of ​​approximately 0.06 m² (equivalent to a sheet of A4 paper measuring 21 x 29.7 cm). This device is powered by a low-voltage DC source of 48V and a low current draw of less than 2A. Its power consumption is less than 100W. Consequently, the device's electromagnetic radiation is extremely low, eliminating any potential adverse effects on human health and preventing the saturation of plant photochromes.

Claims

Claims

1. Photo-biological treatment device (1), comprising: - at least one light-emitting diode (10);- a supervisor (40), adapted to receive a set of parameters relating to periodic light signals to be emitted, and to generate at least one periodic control signal in accordance with the set of parameters received, said set of parameters comprising at least: • a maximum power of the periodic light signals to be emitted, said maximum power being less than 100 W / m2, preferably less than 30 W / m2, • a frequency of the periodic light signals to be emitted, • a duty cycle of said signals, and • an emission duration of the light signals, and - a power supply circuit (50) of the light-emitting diode (10), adapted to receive the control signal generated by the supervisor (40), to generate a periodic current proportional to the control signal received, and to power said light-emitting diode (10) with the generated current.;

2. Device according to claim 1, comprising at least one light-emitting diode (10) emitting in a wavelength range between 260 and 310 nm.

3. Device according to claim 1 or 2, comprising at least two diodes, and the supervisor is adapted to generate at least two different control signals relating to at least two diodes.

4. Device according to claim 3, in which the set of parameters further comprises at least one of the following additional parameters: - a delay time for starting the emission of light signals by a diode or a group of diodes relative to an initial reference time, - a number of repetitions of a treatment phase, where a treatment phase corresponds to the total duration during which light signals are emitted by at least one diode or group of diodes, and - a time interval between two consecutive processing phases.

5. Device according to one of the preceding claims, further comprising a temperature sensor (60) adapted to measure at least one temperature from the following group: - a temperature in the vicinity of at least one light-emitting diode, - a temperature in the vicinity of a heat sink of a diode or a group of diodes, - a temperature of the supervisor, - a temperature in the vicinity of the target to be treated, and the supervisor is configured to receive the temperature measurement and to modify the duty cycle of the control signal and extend the duration of the treatment phase when the measured temperature exceeds a predetermined threshold.

6. Device according to one of the preceding claims, in which the supervisor (40) is configured to modify the control signal in real time as a function of an ambient temperature, a temperature measured in the vicinity of a diode, and a distance between a diode and the target, so that the light signals emitted by the diodes provide a determined energy level at the target.

7. Device (1) according to one of the preceding claims, comprising a plurality of light-emitting diodes (10) arranged in a plurality of parallel rows, in which the pitch between two consecutive diodes of a row and the pitch between two consecutive rows are determined so that the fluence emitted at a plane parallel to the plane of the diodes and located at a determined distance between the diodes and the target is homogeneous.

8. Device (1) according to one of the preceding claims, further comprising a memory (30) storing, for a set of treatments, a set of parameters relating to the light signals to be emitted, and / or a Human-Machine interface (20) adapted to receive a set of parameters relating to the light signals to be emitted from an operator.

9. Device (1) according to one of the preceding claims, in which each light-emitting diode (10) emits in a wavelength range between 200 and 800 nm.

10. Device (1) according to one of the preceding claims, the device being adapted to emit light signals with a frequency between 0 and 10000 Hz, for example between 2 and 100 Hz.

11. Device (1) according to one of the preceding claims, in which each light-emitting diode power supply circuit (50) comprises at least one metal oxide gate field effect transistor and a direct current source connected to the source of the transistor, the control signal generated by the supervisor being connected to the gate of the transistor.

12. Device (1) according to one of the preceding claims, comprising at least one lighting module (90) comprising at least one diode (10) and a diode power supply circuit (50), the lighting module further comprising a heat sink (92) adapted to evacuate the heat generated by the diode(s) (10).

13. Device (1) according to the preceding claim, comprising a housing (100) formed by a set of walls (120), the housing comprising a cavity (110) in which a target to be treated can be placed, and a compartment (130) adjacent to the cavity (110), housing said supervisor (40) and each lighting module (90), in which each lighting module (90) is removably mounted in the compartment (130).

14. Device (1) according to the preceding claim, wherein the housing (100) comprises a front or side wall (121) having an access window (122) to the compartment (130) housing each lighting module (90), said access window (122) being sized to allow the insertion and removal of a lighting module (90) through the window, and the compartment and each lighting module comprise mechanical connectors (93, 94, 103, 104) adapted to allow the mounting and dismounting of a lighting module through the window (122).

15. Device according to claim 14, in which the compartment comprises at least one pin or centering orifice of a module lighting and at least one bolt for fixing said module to the compartment.

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