WO2023052725A1

WO2023052725A1 - Improved photobiological treatment device

Info

Publication number: WO2023052725A1
Application number: PCT/FR2022/051824
Authority: WO
Inventors: Christine ROYNETTE; Patrick ROYNETTE
Original assignee: Asclepios Tech
Priority date: 2021-10-01
Filing date: 2022-09-27
Publication date: 2023-04-06
Also published as: CA3231896A1; FR3127676A1

Abstract

A photobiological treatment device (1) is disclosed, the device comprising: - at least one light-emitting diode (10); - a supervisor (40) suitable for receiving a set of parameters relating to periodic light signals to be emitted, and for generating at least one periodic control signal in accordance with the set of parameters received, said set of parameters comprising at least: o a maximum power of the periodic light signals to be emitted, which power is lower than 100 W/m², o a frequency of the periodic light signals to be emitted, o a duty cycle of said signals, and o a duration of the treatment phase for which the signals are emitted; and - a circuit (50) for supplying the light-emitting diode with power, which circuit is suitable for receiving the control signal generated by the supervisor, for generating a periodic current identical to the control signal received, and for supplying said light-emitting diode with the current generated.

Description

Title: Improved photo-biological treatment device

Technical area

[0001] The present disclosure relates to the field of photo-biological treatment, that is to say the treatment of biological organisms by the use of light signals. It finds specific applications in the field of decontamination, the preservation of foodstuffs or even in the improvement of the nutritional, organoleptic and sanitary qualities of foodstuffs in a sustainable approach and respecting human health, the planet and the animal world. .

Prior technique

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

[0003] The disadvantages of using this type of lamp are multiple. First of all, these lamps are not ecological because they consume a very large amount of electricity and take time to light up because they need to heat up to operate. Mercury vapor lamps have the additional disadvantage of containing mercury, which is harmful to the environment. These lamps are therefore incompatible with eco-design requirements and moreover they will probably be subject to a marketing ban in the near future.

[0004] Moreover, it is also known that plants have photoreceptors sensitive to different wavelengths, and research work is currently exploring the possibilities of using these wavelengths to be able to specifically stimulate certain photoreceptors and thus trigger mechanisms allowing certain properties of the treated plants to be improved. Mention may be made, for example, of 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, or 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 the photoreceptors involved and of the wavelengths to which these photoreceptors are sensitive. However, the mercury vapor lamps or the xenon flash lamps mentioned above 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 possibilities of use for the treatment of living plants sensitive to thermal and electromagnetic radiation.

[0006] In addition, the high light output generated by these lamps is likely to quickly saturate the photo-receptors of the plants, which induces counterproductive stress on the plant, and thus limits the use beyond the simple decontamination of surface without degrading the corresponding foodstuffs.

[0007] Finally, these lamps impose a single mode of use (continuous lighting for mercury vapor lamps, flashes for xenon flash lamps), which greatly limits the diversity of photo-biological treatments as well as the treatment targets. . For xenon flash lamps, the fact that these lamps cover the entire visible spectrum creates a 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 involves an overconsumption of energy in relation to the desired purpose, and therefore a negative ecological impact.

[0008] Given these significant limitations, developments have been carried out to replace these technologies with light-emitting diodes, which have the advantage of reduced power consumption and less heating of the matrix to be processed, since the Light-emitting diodes dissipate heat in the opposite direction to the emission of photons. For example, document WO 2014/036083 is known, which describes a device for storing foodstuffs such as a refrigerator, comprising means for decontaminating the stored foodstuffs, these means comprising sources of UV rays which may be diodes, and a control device capable of operating the sources of UV rays according to different modes such as a sterilization mode and a food preservation mode.

[0009] However, to obtain the expected results of a photo-biological treatment, it is necessary to precisely control the power and the quantity of energy received by the target of the treatment, and therefore to control the lighting sources with precision. . This is confirmed for example by document WO 2018/167439, which describes a method for decontaminating foodstuffs comprising exposing the foodstuffs to pulses luminous in the UV range, the pulses being of a duration comprised between 50 µm and 2s, with an energy density comprised between 0.1 kJ/m ² and 3 kJ/m ² .

[0010] However, these documents do not describe a device making it possible to achieve this level of precision in the control of lighting sources, even when it comes to light-emitting diodes.

Summary

[0011] A photo-biological 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 transmitted, and to generate at least one periodic control signal in accordance with the set of parameters received, said set of parameters comprising at least: o a power maximum of the periodic light signals to be emitted, said maximum power being less than 100 W/m ² , preferably less than 30W/m ² , o a frequency of the periodic light signals to be emitted, o a duty cycle of said signals, and o a duration emitting light signals, and

- a supply circuit for the light-emitting diode, suitable for receiving the control signal generated by the supervisor, for generating a periodic current identical to the control signal received, and for supplying said light-emitting diode with the current generated.

[0012] According to another aspect, there is provided a photo-biological treatment device 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 circuit for supplying the diode(s) of the lighting module; And

- a supervisor, suitable for receiving at least one set of parameters relating to periodic light signals to be emitted, and for generating and transmitting to each lighting module a control signal determined from the parameters received, each lighting module being adapted to receive a control signal generated by the supervisor, to generate a current identical to the control signal received, and to supply said light-emitting diode with the current generated, and in which each lighting module is mounted removably in the photo-biological treatment device.

[0013] In embodiments of this second aspect, the parameters may comprise one or more of the following parameters: a maximum power of the periodic light signals to be transmitted, said maximum power being less than 100 W/m ² , preferably less than 30W/m ² , o a frequency of the periodic light signals to be emitted, o a duty cycle of said signals, and o a 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.

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

[0016] In some embodiments, the device comprises at least two diodes, and the supervisor is suitable for generating at least two different control signals relating to at least two diodes.

[0017] In embodiments, the set of parameters further comprises at least one of the following additional parameters:

- a delay in starting the emission of light signals by a diode or a group of diodes in relation to an initial reference time,

- a number of repetitions of a processing phase, where a processing phase corresponds to the total duration during which light signals are emitted by at least one diode or a group of diodes, and

- a time interval between two consecutive processing phases.

[0018] In embodiments, the device further comprises a temperature sensor suitable for measuring 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 processed, 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 processing 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 level of energy to the level of the target.

In some embodiments, the device comprises a plurality of light-emitting diodes 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 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 some embodiments, the device further comprises a memory storing, for a set of processing operations, a set of parameters relating to the light signals to be transmitted, and/or a Man-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 range of wavelengths between 200 and 800 nm, with an accuracy of 10 nm.

[0023] In embodiments, the device is suitable for emitting light signals with a frequency between 0 and 10,000 Hz, for example between 2 and 100 Hz.

In embodiments, each light-emitting diode power circuit 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.

[0025] In embodiments, the device comprises 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 some embodiments, the device comprises at least one lighting module comprising at least one diode and a power supply circuit for the diode, the lighting module further comprising a heat sink adapted to evacuate the heat generated by the diode(s).

[0027] In some embodiments, the device comprises a casing formed by a set of walls, the casing 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 module lighting module, wherein each lighting module is removably mounted in the compartment.

[0028] In embodiments, the housing comprises a front or side wall comprising an access window to the compartment housing each lighting module, said access window being dimensioned so as 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 comprise a wall separating the compartment and the cavity, said separating wall comprising a through opening, and each lighting module is adapted to be able to be mounted in the compartment so that each diode illuminates the interior of the cavity through the through opening.

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

In some embodiments, the mechanical connectors of the compartment comprise 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 some embodiments, the compartment comprises a projecting abutment for the lighting modules, the abutment being arranged on an edge of the through opening of the partition wall opposite the access window. [0033] In some embodiments, the centering members comprise centering pins arranged on the abutment.

[0034] In some embodiments, the locking members comprise at least one bolt mounted on the partition wall.

The photo-biological treatment device presented above makes it possible to carry out a wide variety of photo-biological treatments on various targets, with great precision. Indeed, it makes it possible to control in real time a light-emitting diode or a group of diodes, to generate periodic light signals corresponding to desired parameters in terms of frequency, duration of the signal, interval between the 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 to be treated.

The use of short-term light signals emitted by light-emitting diodes also makes it possible to limit the light power (irradiance) to which the target is subjected, which makes it possible to avoid saturating the photoreceptors of plants. The control of the parameters of the periodic light signals also allows to control the time of exposure of the target to the light and therefore also the light energy (fluence) received. This makes it possible, in particular in the case of plants and foodstuffs, to carry out an effective treatment without degrading the treated targets.

[0037] In some embodiments, the use of diodes, active or passive heat dissipation systems and/or an adjustment of the parameters of the light signals emitted as a function of the temperature measured at the level of the light-emitting diodes, of the heatsinks, the diode supply circuit and in the vicinity of the targets, makes it possible to control the light signal emitted in real time in order to guarantee optimal treatment of the targets and maximum longevity of the diodes. Regulating the temperature of the diodes makes it possible to operate them in their optimum efficiency zone and therefore to extend their lifespan, with a view to sustainable development.

Brief description of the drawings

[0038] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the appended drawings, in which:

Fig. 1

[0039] [Fig. 1] represents a block diagram of a photobiological treatment device according to one embodiment. Fig. 2

[0040] [Fig. 2] represents an example of a photobiological treatment 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 processing device according to one embodiment.

Fig. 5a

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

Fig. 5b

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

Fig. 6

[0045] [Fig. 6] represents an example of assembly of a lighting module in a photo-biological processing device according to one embodiment.

Fig. 7

[0046] [Fig. 7] represents a compartment of a photo-biological 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 embodiments

With reference to Figures 1 and 2, we will now describe a photo-biological treatment device 1. This device 1 can be used for decontamination or sterilization applications, conservation of foodstuffs, plants or seeds, or even in the improvement of the nutritional, organoleptic and sanitary qualities of foodstuffs, plants or seeds. The photo-biological treatment device 1 can be used on a target to be treated which can be a solid foodstuff, for example harvested fruits and vegetables, or even meat or fish, or liquid, such as for example water, milk, fruit juice or honey. This device can also be used on targets that can be used in agriculture, such as for example seeds or plants, harvested or cultivated flowers, plants cultivated in the ground, in fish farming or aquaculture, etc.

The device 1 comprises at least one light-emitting diode 10, and preferably a plurality of light-emitting diodes 10. In this case where the device comprises several diodes, these can 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.

In order to be able to implement processing adapted to various targets, the device 1 comprises a control circuit 2 described below which is configured to control the emission, by the light-emitting diodes 10, of controlled periodic light signals precisely so as not to exceed a maximum irradiance on the target, that is to say the surface density of energy flux received by the target, expressed in W/m ² , but also to control very precisely the parameters of the light signals emitted, so as to be able to also control the fluence, that is to say the total light energy received by the target. The device 1 typically makes it possible to keep the irradiance on the treated target low, that is to say less than 100W/m ² , typically less than 50W/m ² , or even less than 30 W/m ² , in order not to not saturate plant photoreceptors and so maximize the effects of photoreceptor emission. Referring to Figure 8, there is shown schematically a level of irradiance compared between the device according to the invention, a mercury vapor lamp and a Xenon flash lamp. A mercury vapor lamp produces light, and therefore a continuous irradiance of the order of 10,000 W/m ² , while a Xenon flash lamp emits flashes of very high irradiance (of the order of MW/ m ² ) for a very short duration, with time intervals of the order of 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 whose irradiance level is strictly less than 100 W/m ² .

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

In the case where the device comprises several sets of diodes 10 controlled according to different settings, the following denotes T the total duration of a processing phase comprising the control of several groups of diodes to generate a light signal according to a respective issue duration. The start of the light emission by a group of diodes can be offset with respect to another group of diodes, so that the total duration T of a treatment phase can be greater than the maximum duration of emission of the light signals of all the groups of diodes. Consequently, the parameters defining the light signals emitted respectively by several diodes or set of diodes can also include at least one of the following additional parameters:

- a delay in the start of the emission of light signals in relation to the start of the treatment phase,

- a number of repetitions of the treatment phase, corresponding to a total duration of the treatment,

- a time interval between two consecutive processing phases.

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

In addition, the fact of repeating processing phases, possibly with a time interval between two consecutive processing phases, makes it possible to automate a processing process in which the phases can be repeated at regular time intervals, for example every day, every week, etc. The device 1 is therefore configured to allow the emission of fully controlled periodic light signals, in one or more wavelengths, at low irradiance. The modulation of light signals (periodic signals) makes it possible to increase the efficiency of processing implemented while controlling the exposure time of the target to the light signals, and therefore the total fluence received at the level of the target.

Each light-emitting diode 10 of device 1 is suitable for emitting light at a wavelength of between 200 and 800 nm. Each diode also emits with a precision of 10 nm, i.e. the emission spectrum of each diode is centered on the wavelength of interest by presenting a width of 10 nm at a light energy equal to 90% of the peak light energy. In some embodiments, the device 1 comprises at least one diode 10 or a set of diodes adapted to emit light in a wavelength range between 260 and 310 nm. This range of wavelengths corresponds to a range of maximum sensitivity of the UVR8 photoreceptor in plants, which impacts the nutritional properties and resistance to plant pathogens. Device 1 can also comprise at least one diode 10 or a set of additional diodes in a range of different wavelengths, for example in the visible.

According to a non-limiting example, the device 1 can comprise one or more diodes 10 in the UVC range, for example at 270 nm, one or more diodes 10 in the UV range outside UVC, one or more diodes 10 in the visible range and one or more diodes 10 in the infrared range. The precise selection of the illumination wavelengths, by the selection of the diodes 10, and the control of the modulation of the light signals and of the energy received by the target makes it possible to send precise signals to the photoreceptors of the plants involved in the regulation of phenomena such as germination, vegetative and root growth, flowering, coloring, which allows, for harvested plants, to preserve the plants and increase their organoleptic and nutritional properties, and for cultivated plants, improve crop yield and resistance to diseases and pests. The control of the light signals emitted and therefore of the energy received by the targets makes it possible to trigger biological processes without saturation or harmful stress.

The frequency of the periodic light signals emitted by the diode or diodes 10 is for its part between 1 and 1000 Hz, preferably between 2 and 100 Hz. These low frequencies allow better efficiency of the photo-biological treatments implemented. .

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 light intensity in the axis normal to the lighting surface and of the angle a with respect to this normal according to the following law:

/(z) = /(0)cos(z)

This is applicable to light-emitting diodes, and consequently for an angle a of 60°, the light intensity is equal to 50% of the light intensity at the level of the normal. To obtain a uniform fluence at the level of the target, the diodes are therefore advantageously arranged in a plurality of parallel rows, with a constant pitch between two consecutive diodes of the same row and a constant pitch between two diodes of two consecutive rows, these not being chosen so as to optimize the normal fluence value at any point of a plane parallel to the plane along which the diodes are arranged.

By denoting P the pitch between two consecutive diodes, and D the distance between the diodes and the considered plane, we obtain a homogeneous fluence with the following relation: 60°

For a target positioned at distance D, the light intensity received normal to a diode or at half the pitch between two consecutive diodes is the same. For example, for a linear bar of diodes with a pitch of 4 cm, the distance is equal to 1.16 cm. It should be noted that this proximity is possible with diodes that do not give off heat in the direction of radiation, but in the opposite direction. Moreover, beyond this distance, we can consider all the diodes as a uniform source.

We can use Keith's irradiance formula:

Where E is the irradiance measured at the detector (W/m ² ), P is the power of the diode (W), L the length of the diode (m), D is the distance between the diode and the detector (m) and a = arctan (^) is the half angle of the diode's visual field in radians. In this respect, a light-emitting diode offers a (planar) illumination angle of 120°.

In some embodiments, the device 1 comprises a Man-Machine interface 20 and/or a memory 30 which make it possible to select the parameters of the light signals to be emitted. A memory 30 can in fact store a database in which are recorded, for each of a set of different processing operations, the parameters of the light signals to be emitted for the implementation of this processing operation. A database can relate to treatments associated with a set of foodstuffs, and for each commodity, sets of parameters associated with different types of processing. According to a purely illustrative example, the database can store parameters for various treatments specifically adapted to tomatoes, for example: decontamination, preservation (ie increase in shelf life), and parameters for various treatments specifically adapted to carrots, for example: example: decontamination, preservation, and improvement of nutritional properties.

[0065] In the case of a Man-Machine interface 20, this may comprise, for example, display means, for example a screen with a graphic interface, and information input means, for example a keyboard and /or a mouse and/or a touch screen, allowing an operator to manually enter the parameters of the light signals to be emitted for each set of diodes 10, and to control the start of a treatment. The Man Machine interface 30 can also be coupled to the memory 30, so as to allow an operator to select a set of parameters pre-recorded in the memory 30 and corresponding to a particular type of use of the photo-biological device.

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

[0067] The Man Machine Interface 30 can also make it possible to save a set of parameters for later reuse, and also to record and/or consult a set of processing operations implemented with the device.

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

In embodiments, as shown for example in Figure 2, the photo-biological processing device 1 may comprise a fixed or mobile box 100 containing the light-emitting diodes 10 and the control circuit 2 of the diodes described below. afterwards, and a computer 200 connected to the box, wired or wirelessly, the computer comprising the Human Machine Interface 20, possibly the memory 30 and a computer (not shown) making it possible to communicate the parameters coming from the memory or the Man-Machine interface to the control circuit. As a variant, the photo-biological treatment device 1 can be completely integrated, that is to say comprise a box 100 containing the diodes 10, the control circuit 2 of the diodes, and a Man-Machine interface 20, for example a touch screen, mounted on the case and allowing an operator to enter light signal parameters to be emitted or to select, in a memory also stored in the box or accessible remotely, pre-recorded parameters.

The control circuit 2 of the diodes of the device 1 comprises a DC power supply source (not shown), this source possibly being a battery or an AC/DC converter connected to the mains. For example, the DC supply voltage of device 1 can be 48V. The fact that the device 1 uses a DC power supply makes it possible to greatly limit the electromagnetic fields generated, which is healthier for the operator, and also advantageous in applications to living plants since the electromagnetic fields are liable to saturate certain photoreceptors.

The control circuit 2 further comprises 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 diode(s) 10 , and to generate a periodic control signal, in the form of voltage pulses of constant amplitude, the parameters of which are identical to the set of parameters received. 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.

Consequently, the control signal generated by the supervisor 40 for a diode 10 or a set 11 of diodes comprises a set of voltage pulses, 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 transmitted, and

- A duty cycle r of the voltage pulses, corresponding to the duty cycle T of the pulses of the light signal to be transmitted.

In embodiments in which different light signals must 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. In addition, 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 the light signals in relation to the start of the processing phase, i.e. a delay in the first voltage pulse in relation to the start of the processing phase,

- a number of repetitions of a treatment phase, corresponding to a total duration of the treatment, and

- a time interval between two consecutive processing phases.

Referring to Figure 3, there is shown an example of a set of command signals generated by the supervisor for processing involving three sets of light emitting diodes. The control signals associated with each set of diodes 10 have been noted in the figure LEDi, LED ₂ and LED _3. For the three sets of diodes LEDs, the duration T of the processing phase is common. A treatment phase can for example last between 10 seconds and 1 hour, and can be repeated so that a complete treatment can last several days, even several weeks. Each group is further associated with a frequency fi of the slots (the period T has been shown in FIG. 3 and f _i= 1/Ti) and a duty cycle n of the slots. Moreover, in the example represented, the control signal associated with the first group of diodes LED1 starts at the start of the processing phase but has an emission duration di shorter than the processing phase. The two other control signals associated with the two other groups of diodes LED2, LED3 have a delay t ₂ , t ₃ with respect to the start of the processing phase, but these signals last until the end of the phase. In another example, they could also end before the end of the treatment phase.

For each control signal, the amplitude of the voltage pulses is fixed. For example, the amplitude of the voltage pulses can be a few volts.

[0076] Returning to FIG. 1, the photo-biological processing device 1 also comprises a circuit 50 for supplying the light-emitting diode 10, or a set 11 of diodes, adapted to receive a control signal generated by the supervisor 40, to convert the control signal into current, that is to say to generate a periodic current proportional to the control signal received, and to supply said diode or said set of diodes with the current generated. The current generated by the power supply circuit 50 has the same parameters (frequency, duration emission, duty cycle of the pulses) than the control signal, only the amplitude of the pulses can be different from the amplitude of the pulses of the control signal.

This direct conversion of a control signal to a supply current of the diodes makes it possible to precisely control the switching on and off of the diodes, the switching on corresponding to the phases where the slots of the control signal are at the high level and extinction corresponding to the phases where the slots of the control signal are at 0, since in this case the diodes are no longer supplied with current. In addition, the number of photons emitted by a diode is proportional to the intensity of the current received, therefore the light energy emitted by the diodes supplied by this current is proportional to the duty cycle of the supply current pulses thus generated; a duty cycle of 1 corresponds to a direct current and a maximum energy of the diodes, while a duty cycle of 50% corresponds to a light energy of the diodes equal to half of the maximum energy.

In embodiments, the power supply circuit 50 comprises at least one metal oxide gate field effect transistor (also known by the acronym MOSFET for Metal Oxide Semiconductor Field Effect Transistor) and a current source continuous connected to the source of the transistor, the control signal received from the supervisor being connected to the gate of the transistor. In this way, when the pulses of the control signal are at their maximum amplitude, the transistor turns on and the current generated by the current source is supplied to the diodes. When the gates of the control signal are at zero, the transistor acts as an open switch, no current reaches the diodes and they turn off.

The device can also comprise several supply circuits 50 adapted to each supply a set of diodes comprising several diodes of the same or of different wavelengths. In this case, each 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 supply circuit 50. The use of several power supply circuits 50 receiving respective control signals therefore makes it possible to drive several sets of diodes 10 differently.

The control circuit 2 described previously 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 photo-biological processing device 1 may comprise one or more temperature sensors 60, suitable for measuring 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 with at least one light-emitting diode, examples of heat sinks are described in more detail below,

- in the vicinity of the target to be processed, 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 the latter.

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

The supervisor 40 can also be configured to modify the control signal in real time according to the measured temperature in order to avoid overheating of the target to be processed and overheating of the diodes. In one embodiment, when the temperature measured in the vicinity of the diodes and/or the target exceeds a determined threshold, the supervisor is configured to modify the duty cycle, in particular to reduce the duty cycle of the pulses of the control signal, and to lengthen the respective emission durations of each diode or group of diodes. Indeed, the reduction in the duty cycle makes it possible to reduce the light power and therefore the production of heat, and the extension of the duration of the phase makes it possible to compensate for this reduction in power to remain at iso-energy. In this way, the supervisor can generate control signals slaved to the temperature measured in the vicinity of the diodes to limit heating of the target and of the diodes, but maintain the same total light energy received by the target.

[0083] The fact of regulating the temperature as a function of the temperature at the level of the target makes it possible to prevent excessive heat from degrading the target to be treated. The fact of regulating the temperature according to the temperature of the diodes makes it possible to always operate the diodes in their zone of maximum efficiency and to limit their aging. This makes it possible to guarantee a maximum period of use of the diodes by avoiding premature ageing.

The Man 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 parameters of the control signal have been modified. given a measured temperature.

In some embodiments, the photo-biological processing device 1 can also comprise a distance sensor 70 between the diode(s) and the target, and the supervisor 40 can be configured to modify each control signal in real time. depending on the distance between the diode and the target, so that the energy level received by the target is always equal to a determined energy level. The control signal can also be adapted according to the ambient temperature and the temperature measured in the vicinity of a diode, as described above.

Furthermore, in certain embodiments, the device 1 can comprise means 71 for adjusting the distance between the diode(s) and the target. It can be for example a support positioned under the target and having an adjustable height. The distance between the diode or diodes and the target is advantageously displayed by the Man-Machine interface.

[0087] Referring to Figures 4, 5a and 5b, in embodiments, the photo-biological processing 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 supply circuit 50 of this set of diodes. The lighting module may include a mechanical support for the diodes, for example a printed circuit 91, also making it possible to ensure the electrical connection of the diodes to the power supply circuit 50.

[0088] In embodiments, each lighting module 90 further comprises a heat sink 92 adapted to evacuate the heat generated by the diode or diodes. The heat sink can 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 carrying the diodes, that is to say on the side opposite to the side where the diodes emit. light, since this is the side where the diodes emit the most heat. Each lighting module can also comprise a temperature sensor, this sensor being for example inserted between two consecutive diodes or between two rows of diodes of the module or in the dissipator, making it possible to measure the temperature in the vicinity of the diodes. The supply circuit 50 of the diodes 10 of the lighting module 90 is connected to the supervisor 40, and is configured to receive a control signal for all of the diodes 10 of the lighting module, whether these present the same wavelength or not.

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

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.

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

The processing 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 which can accommodate a plurality of lighting modules 90. The walls of the case can be perforated in order to ensure ventilation of the air contained in the compartment and therefore the cooling of the latter.

[0094] Each lighting module 90 is removably mounted in the compartment 130, and comprises in this respect removable mechanical connection means 93,94 making it possible to attach or remove a lighting module 90 from the compartment 130, and electrical connection means (not shown) which are also removable, making it possible to connect or disconnect the lighting module 90 from the supervisor. The box 100 also includes removable mechanical connection means 103, 104 adapted to cooperate with those of each lighting module. The connector also comprises electrical connection means (removable) allowing its connection or disconnection from the lighting module 90.

In the example shown in Figures 2 and 7, the housing 100 may be of substantially parallelepipedal shape, the cavity 110 and the compartment 130 also being parallelepipedic. The compartment can be positioned above the cavity 110 receiving the target to be treated, being separated from this cavity by a separation wall 140 comprising a through opening 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 while forming a mechanical support for the lighting modules 90. Alternatively and as shown in Figure 7, the through opening 141 may comprise a single, continuous opening in the dividing wall 140, which is sized so that each lighting module 90 can rest on two opposite edges of the through opening, or that it can be kept suspended above the through opening by the mechanical connection means of the case. According to yet another variant represented schematically in FIG. 2, the through opening may comprise several adjacent openings, one for each lighting module, each opening being separated from an adjacent opening by a strip 142 making it possible both to delimit slots for the lighting modules and optionally to form a support for the modules.

In one embodiment, the box 100 is configured to allow easy access to the lighting modules 90, as well as simple assembly and disassembly of the latter. For example, a wall 121 of the box 100, advantageously a front or side wall, that is to say the wall of the box intended to face the operator, can comprise an access window 122 dimensioned so as to allow inserting and removing a lighting module through the access window. Advantageously, the access window is also dimensioned so that an operator can pass his arm or both arms through it. This access window can advantageously be closed by a door to prevent dust from settling in the compartment. For example, an opening allowing access to the cavity to place the target to be treated therein and the access window to the compartment 130 can be arranged in the same wall of the box.

Furthermore, the compartment 130 of the box 100 and each lighting module 90 include mechanical connectors 103, 104 which allow the mounting and dismounting of the lighting module through the access window 122. In the embodiment shown in Figures 6 and 7, the mechanical connectors 103,104 of the compartment 130 are carried 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 wall of the compartment opposite the wall 121 in which the access window is arranged. To limit manipulations to a zone close to the access window, the mechanical connectors can for example comprise centering members 103 which are arranged at the edge of the through-opening 141 farthest from the access window, these members centering which can comprise for example one or more projecting centering pin(s) which can be housed in one or more complementary bore(s) 93 provided on a lighting module, or vice versa. THE Mechanical connectors may also include locking members 104, arranged in the vicinity of the edge of the through opening closest to the access window. These locking members can for example comprise a bolt 104 carried by a wall, for example the partition wall, which an operator engages in an orifice 94 provided for this purpose on the lighting module.

The box 100 may also include a stop 105 arranged on the partition wall at the edge of the through opening farthest from the access window, or on the wall opposite the access window. The centering members 103 of the box can be mounted on said abutment 105, as is the case in FIG. 7 where the centering pins project from the abutment towards the access window.

In this embodiment, each lighting module 90 has the shape of a parallelepiped extending along a main direction. Each lighting module successively comprises, in this main direction, a box 95 housing the supply circuit 50 of the diodes 10 then the printed circuit 91 on which are mounted one or two rows of diodes 10, at the rear of which is the heat sink 92. The centering member 93 carried by the lighting module can be located at the opposite end of the lighting module with respect to the box 95 housing the power supply circuit, and the locking member 94 can be found at the end of the lighting module corresponding to the box housing the power supply circuit. In this way, an operator can insert a lighting module 90 through the access window of the box 100, by first inserting the end of the module comprising the centering member 93, until this end reaches the stop and that the centering members 93 of the module cooperate with those 103 of the case. 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 bolt 104 provided for this purpose. The power supply circuit 50 of the diode being located on the side of the access window, the electrical connection of the latter with the supervisor is facilitated 40. The operator can then close the access window 122.

In an exemplary embodiment, a photo-biological treatment device according to the preceding description is produced with three lighting modules comprising 250 LEDs distributed over six rows, representing an emission surface of the order of 0.06 m ² (area equivalent to that of an A4 21*29.7 cm sheet). Such a device is powered by a DC low voltage source of 48V and by a low power supply current of less than 2A. The consumption of such a device is less than 100W. Consequently, the electromagnetic radiation from the device is particularly limited, which eliminates the harmful impacts on human health as well as the saturation of plant photochromes.

Claims

-23- Claims

[Claim 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 transmitted, and to generate at least one periodic control signal in accordance with the set of parameters received, said set of parameters comprising at least: o a maximum power of the periodic light signals to be emitted, said maximum power being less than 100 W/m ² , preferably less than 30W/m ² , o a frequency of the periodic light signals to be emitted, o a duty cycle of said signals, and o a duration of emission of the light signals, and

- a supply circuit (50) for 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 supply said light-emitting diode (10) with the generated current.

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

[Claim 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.

[Claim 4] Device according to claim 3, in which the set of parameters further comprises at least one of the following additional parameters:

- a time interval between two consecutive processing phases.

[Claim 5] Device according to one of the preceding claims, in which the periodic control signal and the supply current of the diode are pulsed signals.

[Claim 6] 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 supervisor temperature,

[Claim 7] 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 level of energy at the level of the target.

[Claim 8] 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 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.

[Claim 9] Device (1) according to one of the preceding claims, further comprising a memory (30) storing, for a set of processing operations, a set of parameters relating to the light signals to be emitted, and/or a human interface Machine (20) adapted to receive a set of parameters relating to the light signals to be emitted from an operator.

[Claim 10] Device (1) according to one of the preceding claims, in which each light-emitting diode (10) emits in a range of wavelengths between 200 and 800 nm, with an accuracy of 10 nm.

[Claim 11] Device (1) according to one of the preceding claims, the device being adapted to emit light signals of a frequency between 0 and 10,000 Hz, for example between 2 and 100 Hz.

[Claim 12] Device (1) according to one of the preceding claims, in which each light-emitting diode 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.

[Claim 13] 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 supply circuit (50), the module lighting device further comprising a heat sink (92) adapted to evacuate the heat generated by the diode(s) (10).

[Claim 14] 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), wherein each lighting module (90) is removably mounted in the compartment (130).

[Claim 15] Device (1) according to the preceding claim, in which the housing (100) comprises a front or side wall (121) comprising an access window (122) to the compartment (130) housing each lighting module ( 90), said access window (122) being sized to allow insertion and removal of a light module (90) through the window, and the compartment and each light module include mechanical connectors (93, 94, 103, 104) adapted to allow mounting and dismounting of a lighting module through the window (122).

[Claim 16] Device according to claim 15, in which the compartment comprises at least one pin or orifice for centering a lighting module and at least one bolt for fixing said module to the compartment.

[Claim 17] Photo-biological treatment method, comprising exposing a biological organism to one of the periodic light signals in accordance with a set of parameters comprising: -26-

- a maximum power of the periodic light signals to be transmitted, said maximum power being less than 100 W/m ² , preferably less than 30 W/m ² ,

- a frequency of the periodic light signals to be emitted,

- a duty cycle of said signals, and - a duration of emission of the light signals, said periodic light signals being generated by a device according to one of the preceding claims.

[Claim 18] Process according to the preceding claim, in which the photo-biological treatment is one of a treatment for decontamination, sterilization, preservation or improvement of nutritional qualities. .