Aerosol generation device with optical heating

Abstract

In a first aspect, the invention is an aerosol-generating device comprising at least two light sources emitting light onto at least one same portion of an aerosol-generating substrate received by the aerosol generation device, for generating an aerosol, wherein a first beam-on time of emitting light from the first light source onto the portion of the aerosol-generating substrate is non-overlapping with a second beam-on time of emitting light from a second light source of the at least two light sources onto the least one same portion of the aerosol-generating substrate.

Description

[0001] AEROSOL GENERATION DEVICE WITH OPTICAL HEATING

[0002] FIELD OF INVENTION

[0003] The present invention relates to an aerosol generation device, in particular an aerosol generation device comprising one or more light sources for optically heating an aerosolgenerating substrate.

[0004] TECHNICAL BACKGROUND

[0005] Aerosol generation devices of the prior art commonly found on the market employ thermal heating, wherein a heating system generates heat and contacts and transfers the generated heat to an aerosol-generating substrate, typically either directly via conduction or via convection by heating air drawn into the aerosol-generating device.

[0006] As an alternative, non-contact heating such as optical heating can be employed. In optical heating, only the parts of the aerosol-generating substrate that absorb generated light are heated. Optical heating can therefore selectively target localized portions of the aerosol-generating substrate, and thus allows faster generation of an aerosol.

[0007] However, different aerosol-generating substrates as well as different constituents therein have different optical absorption properties. Current optical heating methods and means do not account for these different optical absorption properties.

[0008] It is therefore an object of the present invention to provide an aerosol generating device and method employing optical heating that are capable of providing an aerosol with a desired composition and amount.

[0009] SUMMARY OF THE INVENTION

[0010] Some, or all the above issues of the prior art are addressed by the invention as defined by the features of the independent claims. Preferred embodiments of the invention are defined by the features of the dependent claims.

[0011] In a 1staspect, the invention is an aerosol-generating device comprising at least two light sources configured for emitting light onto at least one same portion of an aerosolgenerating substrate received by the aerosol generation device, for generating an aerosol. The first beam-on time of emitting light from the first light source onto the portion of the aerosol-generating substrate is non-overlapping with a second beam-on time of emitting light from a second light source of the at least two light sources onto the at least one same portion of the aerosol-generating substrate.

[0012] The 1staspect of the invention provides several advantages. Optical heating using light that is emitted onto and that is absorbed by the same portion of an aerosol-generating substrate provides a low maintenance aerosol-generating device that can generate an aerosol from the portion of the aerosol-generating substrate rapidly and with high efficiency. The aerosol-generating substrate can be heated in a more targeted, localized, and effective manner, as light can be readily focused and directed, and only the portion of the aerosol-generating substrate onto which light is emitted is heated without thermal energy loss.

[0013] It has to be noted that the beam-on times of the at least two light sources are not overlapping, thus the beam-on times are different and therefore the at least two light sources can be selectively and independently activated so that the light can be directed to the same portion of the substrate at different times, preferably in sequence.

[0014] By having non-overlapping beam-on times for the at least two light sources, different components of the aerosol-generating substrate having different optical absorption spectra can be separately heated, preferably sequentially heated, thus improving control over the process of heating the aerosol-generating substrate.

[0015] According to a 2ndaspect, according to the first aspect, the first light source comprised by the at least two light sources is configured to emit light with a wavelength within a first range of 380 nm to 500 nm, preferably of 430 nm to 470 nm, more preferably of 440 nm to 460 nm, most preferably of about 450 nm.

[0016] According to a 3rdaspect, in any of the preceding aspects, the at least two light sources comprise a first light source configured to emit light with a wavelength within a first range and a second light source configured to emit light with a wavelength within a second range, wherein the first range and the second range are different one from another.

[0017] Advantageously, the applicant has found that many substrates, including tobacco substrates, have optical absorption properties that are enhanced at a wavelength, preferably within the first range indicated above. Consequently, by providing at least two light sources, with the first light source emitting light within the first range and the second light source emitting light preferably within a second having a beam-on time different form the beam-on time of the first light source, optical heating of the aerosolgenerating substrate can be controlled to be more efficient, effective, and flexible.

[0018] Advantageously, the use of at least two light sources emitting lights on the same portion of the aerosol-generating substrate with a wavelength within a first range and within a second range, wherein the first and the second ranges are different, allows to effectively heat different components of the aerosol-generating substrate.

[0019] According to a 4thaspect, in any of the preceding aspects, the first beam-on time and the second beam-on time are operated in sequence, preferably sequentially alternated.

[0020] The 4thaspect is advantageous as it allows the aerosol-generating substrate to be heated in more homogeneous manner. By operating ins sequence, preferably by alternating, the first beam-on time and the second beam-on time, different components of the aerosol-generating substrate are heated in an alternating fashion, thereby preventing components from being overheated or depleted before other components have been heated.

[0021] According to a 5thaspect, in any one of the preceding aspects, the first beam-on time is longer than the second beam-on time.

[0022] The 5thaspect is advantageous as it improves the heating performance of the aerosolgenerating device. Adjusting the length of the first beam-on time and the beam-on time relative to each other allows the optical heating to be adjusted according to the optical absorption profile of the aerosol-generating substrate, and generation of an aerosol can be better controlled.

[0023] Notably, this is particularly advantageous for light emitted by the first light source that is within the first range as defined for the 2ndand 3rdaspects. Due to the preferential absorption of light within the first wavelength range, optical heating using light in the first wavelength range is effective. Therefore, it is advantageous to set the first beam-on time for light within the first wavelength range to be longer than the second-beam one.

[0024] According to a 6thaspect, in the preceding aspect, the first beam-on time is between 5 to 15 times longer, preferably between 7 to 13 times longer, more preferably between 9 to 11 times longer than the second beam-on time.

[0025] The 6thaspect is advantageous as it further increases the heating performance of the aerosol-generating device. The applicant has found that the above ratios between the first beam-on time and the second beam-on time represent optimal ratios to achieve improved heating of the aerosol-generating substrate.

[0026] According to a 7thaspect, in any one of the preceding aspects, light from the first light source is emitted at a first amplitude that is substantially the same as the amplitude of the light emitted by the second light source.

[0027] The 7thaspect is advantageous as it improves control over the process of heating the aerosol-generating substrate. The amplitude of the emitted light is directly linked to the intensity of the emitted light and therefore the energy absorbed by the aerosolgenerating substrate. Emitting light from the first light source with the same amplitude as light from the second light sources minimizes deviations between the light sources, and thus affords improved control.

[0028] According to a 8thaspect, in any one of the preceding aspects, the at least two light sources further comprise a third light source configured to emit light onto the at least one same portion of the aerosol-generating substrate, wherein a third beam-on time of emitting light from the third light source onto the at least one same portion of the aerosol-generating substrate is non-overlapping with the first and / or the second beam- on time.

[0029] 8thaspect is advantageous as it improves to the heating of the aerosol-generating substrate. Adding a third light source further improves the heating performance of the aerosol-generating device.

[0030] According to a 9thaspect, in the preceding aspect, the first beam-on time, the second beam-on time, and the third beam-on time are operated in sequence, preferably sequentially alternated.

[0031] The advantages of the 9thaspect correspond to the advantages of the 4thaspect.

[0032] According to 10thaspect, in to any one of the 8thor 9thaspects, the first beam-on time is longer than the third beam-on time.

[0033] The advantages of the iothaspect correspond to the advantages of the 6thaspect.

[0034] According to a 11thaspect, in any one of the 8thto 10thaspects, light from the first light source is emitted at a first amplitude that is substantially the same as the amplitude of the light emitted by the third light source. The advantages of the 11thaspect correspond to the advantages of the 7thaspect.

[0035] According to a 12thaspect, in any one of the preceding aspects, one or more of the at least two light sources are coherent light sources.

[0036] The 12thaspect is advantageous, since coherent light sources, such as, for example, lasers, usually have a small beam divergence that allows specific portions of a substrate to be accurately targeted without the focusing optics. Additionally, by setting nonoverlapping beam-on times, interferences between coherent lights, emitted by the at least two light sources, that can detrimentally affect illumination of the aerosolgenerating substrate with light from the at least two light sources can be reduced, thus improving the heating performance of the aerosol-generating device.

[0037] According to a 13thaspect, in any one of the preceding aspects, one or more of the at least two light sources are non-coherent light sources.

[0038] The 13thaspect is advantageous as non-coherent light sources, such as, for example, LEDs, are smaller and require less power.

[0039] According to a 14thaspect, in any one of the preceding aspects, the aerosol-generating device further comprises a control unit for controlling operational parameters of the at least two light sources, wherein the operational parameters comprise one or more of the beam-one time of one or more of the at least two light sources and an amplitude of the light emitted from one or more of the at least two light sources.

[0040] A 15thaspect of the invention is an aerosol-generating system comprising the aerosolgenerating device, according to any one of the 1stto 14thaspects, and an aerosolgenerating article comprising an aerosol-generating substrate, wherein the aerosolgenerating article is received by the aerosol-generating device.

[0041] The advantages of the 15thaspect correspond to the advantages of the 1stto 14thaspects.

[0042] A 16thaspect of the invention is a method of generating an aerosol, the method comprising generating an aerosol by receiving an aerosol-generating substrate by an aerosol-generating device comprising at least two light sources. The method comprises generating and emitting light from the at least two light sources onto at least one same portion of the aerosol generating-substrate received by the aerosol generation device, wherein a first beam-on time of emitting light from the first light source onto the at least one same portion of the aerosol-generating substrate is non-overlapping with a second beam-on time of emitting light from a second light source of the at least two light sources onto the at least one same portion of the aerosol-generating substrate.

[0043] According to a 17thaspect, in the preceding aspect, the first light source comprised by the at least two light sources is configured to emit light with a wavelength within a first range of 380 nm to 500 nm, a preferably of 430 nm to 470 nm, more preferably of 440 nm to 460 nm, most preferably of about 450 nm.

[0044] According to a 18thaspect, in any one of the preceding aspects the at least two light sources comprise a first light source configured to emit light with a wavelength within a first range and a second light source configured to emit light with a wavelength within a second range, wherein the first range and the second range are different one from another.

[0045] According to a 19thaspect, in the preceding aspect, the method comprising operating in sequence, preferably sequentially alternating, the first beam-on time and the second beam-on time.

[0046] According to a 20thaspect, in any one of the preceding aspects, the first beam-on time is longer than the second beam-on time.

[0047] According to a 21staspect, in the preceding aspect, the first beam-on time is between 5 to 15 times longer, preferably between 7 to 13 times longer, more preferably between 9 to 11 times longer than the second beam-on time.

[0048] According to a 22ndaspect, in any one of the preceding aspects, the method comprising emitting light from the first light source at a first amplitude, and emitting light from the second light source at a second amplitude, wherein the first amplitude and the second amplitude are substantially the same.

[0049] According to a 23rdaspect, in any one of the preceding aspects, the at least two light sources further comprise a third light source, the method further comprising emitting light from the third light source onto the at least one same portion of the aerosolgenerating substrate, wherein a third beam-on time of emitting light from the third light source onto the at least one same portion of the aerosol-generating substrate is non-overlapping with the first and / or the second beam-on time. According to a 24thaspect, in the preceding aspect, the method comprising operating in sequence, preferably sequentially alternating, the first beam-on time, the second beam- on time, and the third beam-on time.

[0050] According to a 26thaspect, in to any one of the 23rdor 24thaspects, the first beam-on time is longer than the third beam-on time.

[0051] According to a 27thaspect, in any one of the 23rdto 26thaspects, light from the first light source is emitted at a first amplitude that is substantially the same as the amplitude of the light emitted by the third light source.

[0052] According to a 28thaspect, in any one of the preceding aspects, one or more of the at least two light sources are coherent light sources.

[0053] According to a 29thaspect, in any one of the preceding aspects, one or more of the at least two light sources are non-coherent light sources.

[0054] According to a 30thaspect, in any one of the preceding aspects, the method further comprises controlling, via a control unit of the aerosol-generating device, operational parameters of the at least two light sources, wherein the operational parameters comprise at least one of the beam-one time of one or more of the at least two light sources and an amplitude of the light emitted from one or more of the at least two light sources.

[0055] The advantages of the 16thto 30thaspects correspond respectively to the advantages of the 1stto 15thaspects.

[0056] BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Fig. 1 shows a schematic illustration of the electronic configuration of an aerosolgenerating device, according to embodiments of the invention.

[0058] Figs. 2A and 2B respectively show schematic illustrations of aerosol-generating devices and aerosol-generating articles for use with the aerosol-generating devices, according to embodiments of the invention.

[0059] Figs. 3A and 3B respectively show schematic illustrations of interior cross-sectional views of aerosol-generating devices and aerosol-generating articles in use with the aerosol-generating devices, according to embodiments of the invention. Figs. 4A and 4B respectively show schematic illustrations of a side view of aerosolgenerating units configured to emit light onto aerosol-generating substrates, according to preferred embodiments of the invention.

[0060] Figs. 5A and 5B respectively show schematic illustrations of a plan view of aerosolgenerating units configured to emit light onto aerosol-generating substrates of the preferred embodiments shown in Figs. 4A and 4B.

[0061] Figs. 6A, 6B, and 6C respectively show schematic illustrations of a side view, a plan view, and a side view of aerosol-generating units configured to emit light onto aerosolgenerating substrates, according to different embodiments of the invention.

[0062] Fig. 7 shows a schematic diagram illustration of a method of operating an aerosolgenerating device according to preferred embodiments of the invention.

[0063] DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0064] Preferred embodiments are now described, by way of example only, with reference to the accompanying drawings.

[0065] In the description of the present invention, it should be understood that the terms "one end", "the other end", "outer side", "upper", "above", "inner side", "under", “below”, "horizontal", "coaxial", "central", "end" "part", "length", "outer end" etc., which indicate the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings. The terms such as "upper", "above", "below", "under" and the like used in the present invention to indicate a relative position in space are used for the purpose of facilitating explanation to describe a unit or feature shown in the drawings relative to the relationship of another unit or feature. The term of the relative position in space may be intended to include different orientations of the device in use or operation other than those shown in the figures. For example, if the device in the figure is turned over, the unit described as being "below" or "under" other units or features will be "above" the other units or features. Therefore, the exemplary term "below" can encompass both the above and below orientations. The device can be oriented in other ways (rotated by 90 degrees or other orientations), and the space- related descriptors used herein are explained accordingly. More specifically, the word “above” means that one unit, layer or element is arranged or configured relatively in an exterior direction of the device towards the (an)other unit(s), layer(s) or element(s); the word “below” means that one unit, layer or element is arranged or configured relatively in an interior direction of the device towards the other units, layers or elements.

[0066] Aerosol-generating devices according to the invention are preferably portable devices. For this purpose, they are of limited size. According to preferred embodiments of the invention, the portable aerosol-generating devices are hand-held devices that fit into a hand of a user and that can be operated by hand.

[0067] The aerosol-generating device loo comprises an outer housing or casing within which components of the aerosol-generating device are arranged. The aerosol-generating device according to the invention houses an aerosol generation unit that is configured to generate an aerosol from an aerosol generation substrate using light.

[0068] Fig. i illustrates an electronic configuration of an aerosol-generating device too according to embodiments of the invention. As a preferably portable and handheld device, the aerosol-generating device too further comprises a power source 150, such as, for example, a rechargeable and / or replaceable battery. The power source is configured to provide power to electronic components of the aerosol-generating device too. In preferred embodiments, a control unit 140 is provided with the aerosolgenerating device too, wherein the control unit is configured for controlling various functions for the functioning of the aerosol-generating device too. In preferred embodiments, the control unit is configured to control operation of the aerosolgenerating unit 110 for heating the aerosol-generating substrate 210 to generate an aerosol. The aerosol-generating unit 110 is shown exemplary in Fig. 1 to comprise a first light source, a second light source, and a third light source. However, the number of light sources maybe more or less. While each of the light sources of aerosol-generating unit 110 can be pre-programmed or set to emit light with predetermined operational parameters, it is preferred that the control unit 140 is configured to control operational parameters of the aerosol-generating unit 110 comprising the at least two light sources. Operational parameters of some or all of the at least two light sources that can be controlled by the control unit 140 comprise one or more of: beam-on time during which light is emitted, beam-off time during which light is not emitted, amplitude of the emitted light / light beam intensity, phase of the emitted light, beam profile of the emitted light, and wavelength of the emitted light. It has to be noted that the above reported operational parameters of some or all of the at least two light sources can be controlled independently one from another or two or more of them can be controlled simultaneously. According to an embodiment, the beam-on time is defined as the duration during which light is emitted from the light sources onto the aerosol-generating substrate. The first beam-on time, associated with the first light source, is different from the second beam-on time, associated with the second light source.

[0069] As shown in Figs. 2A to 2B, the aerosol generation device may have a generally longitudinal shape in the longitudinal direction y, and a substantially circular or elongated cross-section in the transverse direction x. However, other shapes of the aerosol-generating device too and with different cross-sections are possible. The longitudinal direction y is parallel to the inhalation direction, i.e., the direction in which the aerosol-generating device too is inserted or brought to a user’s mouth for inhaling a generated aerosol, and the transverse direction x is perpendicular to the inhalation direction.

[0070] In an embodiment, the aerosol-generating substrate is a solid substrate such as, for example, a tobacco substrate. A tobacco substrate comprises tobacco which may be in the form of ground or milled tobacco leaves. Additionally, the tobacco substrate may comprise gellan gum, and additionally, or alternatively a CMC binder. Both gellan gum and CMC binder can act binders, thickeners, and / or stabilizers.

[0071] In an embodiment the aerosol-generating substrate is liquid substrate, such as, for example, an e-liquid or a t-liquid. An e-liquid typically comprises vegetable glycerin (VG), propylene glycol (PG) nicotine, and flavoring. A T-liquid typically comprises vegetable glycerin (VG), propylene glycol (PG) and tobacco material such as ground tobacco.

[0072] Constituents of the aerosol generating substrate may have different optical absorption spectra. Advantageously, according to an embodiment, by providing light of different wavelength it was possible to separately heat the components by making use of the different optical absorption spectra of the constituents. According to an embodiment, the ability to heat different constituents separately provides precise control over the heating process, leading to more efficient aerosol generation and enhanced flavor or nicotine delivery, depending on the constituents involved. Furthermore, this allow for the customization of the aerosol-generating process based on the desired outcome, such as varying the intensity or duration of heating for specific constituents to achieve different aerosol characteristics. Liquid aerosol-generating substrates are stored in a reservoir. The aerosol-generating device loo unit is provided with extraction means configured for extracting the aerosolgenerating substrate. In an embodiment, the extraction means comprises an element, such as, for example, a wicking element, that is in contact with the liquid aerosolgenerating substrate stored in the reservoir and that is configured to draw the liquid aerosol-generating substrate 210 from the reservoir. The reservoir can be provided as part of the aerosol-generating device 100, wherein an opening is provided to allow liquid aerosol-generating substrate to be filled into the reservoir.

[0073] Solid aerosol-generating substrates can be provided in different shapes and sizes. As shown in Fig. 2A, the aerosol-generating article can be an aerosol-generating substrate 210 that is a tobacco substrate that may also have a shape that is elongated in the longitudinal direction y with a circular or elliptical base shape in the transverse direction x, the shape of the aerosol-generating substrate 210 emulating the shape of a traditional cigarette. Alternatively, as shown for a preferred embodiment illustrated in Fig. 2B, the solid aerosol-generating substrate 210 may be disk-shaped, or, alternatively, half-spherical, spherical, or ellipsoidal. In many cases, the aerosolgenerating article 200 may substantially correspond to the aerosol-generating substrate 210.

[0074] As shown in Figs. 3A and 3B, for use of the solid aerosol-generating substrate, it is preferred the aerosol-generating device too is provided with receiving means for receiving the solid aerosol-generating substrate. The receiving means may be a cavity or chamber 105 into which the solid aerosol-generating substrate 210 can be partially or fully inserted. The size and shape of the cavity or chamber 105 can be adapted depending on the size and shape of the solid aerosol-generating substrate 210. For example, in case the solid aerosol-generating substrate 210 is of the shape emulating a traditional cigarette, the cavity or chamber 105 is preferably of a tubular shape. The cavity or chamber 105 is preferably also a vaporization chamber. The vaporization chamber encloses the vaporization space within which an aerosol is generated when heated.

[0075] Alternatively, for liquid aerosol-generating substrates, the reservoir for storing the liquid aerosol-generating substrates can be provided with an aerosol-generating article 200, such as, for example, a cartridge that comprises an outer housing or casing within which the reservoir is provided. In use, the aerosol-generating article can detachably connect to the aerosol-generating device. When the aerosol-generating article 200 is attached to the aerosol-generating device too, the aerosol-generating unit no is configured to extract the liquid aerosol-generating substrate 210 from the reservoir of the aerosol-generating article 200 and heat the drawn aerosol-generating substrate

[0076] 210.

[0077] Alternatively, the solid aerosol-generating substrate 210 may be provided as part of an aerosol-generating article 200 that is in the form of a cartridge. The cartridge comprises an outer housing or casing within which the solid aerosol-generating substrate 210 is provided. The cartridge, and additionally, or alternatively, the aerosolgenerating device 100 is / are configured such that, when the cartridge is received by the aerosol-generating device 100, the aerosol-generating unit 110 of the aerosolgenerating device too can heat the solid aerosol-generating substrate 210 that is provided as part of the cartridge.

[0078] According to the invention, the aerosol-generating unit 110 is configured to emit light onto an aerosol-generating substrate 210 for heating the aerosol-generating substrate 210 to generate an aerosol. The configuration and arrangement of the aerosolgenerating unit 110 in the aerosol-generating device too depends on the type of aerosol-generating article 200 as well as the manner, in which an aerosol-generating article 200 comprising the aerosol-generating substrate 210 is received. The configuration and arrangement of the aerosol-generating unit 110 may also depend on the way an aerosol-generating substrate 210 is to be heated.

[0079] As can be seen in Figs. 3A and 3B, the aerosol-generating article 200 that is exemplified as a disk shape but may have any shape described in the context of Figs. 2A and 2B, is partially or fully received in a cavity or chamber 105 of the aerosol-generating device too. For heating the aerosol-generating substrate 210, the aerosol-generating unit 110 is preferably arranged at an inner surface of the cavity or chamber 105 as a vaporization space to allow the aerosol-generating unit 110 to emit light directly onto the aerosolgenerating substrate 210 to generate an aerosol within the cavity or chamber 105. For this purpose, the aerosol-generating unit 110 may be arranged inside a groove or cutout provided at the inner surface of the cavity or chamber 105 so that protrusion of the aerosol-generating unit 110 from the inner surface of the cavity of chamber 105 is minimized or eliminated. Alternatively, as a configuration that is simpler to manufacture, the aerosol-generating unit 110 can be provided on the inner surface of the cavity or chamber 105. Furthermore, the aerosol-generating unit 110 maybe arranged to be distanced from the aerosol-generating substrate 210 in a transverse direction x, as shown in Fig. 3A, or alternatively, the aerosol-generating unit 110 may be arranged to be distanced from the aerosol-generating substrate 210 in the longitudinal direction y, as shown in Fig. 3B. Additionally, and irrespective of the positioning and orientation of the at least two light sources of the aerosol-generating unit 110 relative to the aerosol-generating substrate 210, In both cases, one or more of the at least two light source may be arranged on an inner surface of the chamber 105, or may be recessed into an inner surface of the chamber 105. Notably, the aerosol generating unit 110 may be configured as described below in the context of Figs. 4Ato 6C.

[0080] In a case where the aerosol-generating substrate 210 is comprised by an aerosolgenerating article 200 that is in the form of a cartridge, the aerosol-generating unit 110 is preferably arranged at or proximate the interface between the aerosol-generating device 100 and the aerosol-generating article 200 when, in use, the aerosol-generating article 200 is attached to the aerosol-generating device too. Additionally, or alternatively, it is preferred that the aerosol-generating substrate 210 comprised by the aerosol-generating article 200 is arranged at or proximate the interface between the aerosol-generating device too and the aerosol-generating article when, in use, the aerosol-generating article 200 is attached to the aerosol-generating device too. When the aerosol-generating article 200 is attached to the aerosol-generating device too, the aerosol-generating substrate 210 comprised by the aerosol-generating article, and the aerosol-generating unit 110 are arranged such that light emitted from the aerosolgenerating unit 110 is incident onto the aerosol-generating substrate 210.

[0081] Considering that all light sources have a certain spectral bandwidth, it is to be noted that the term wavelength of light emitted by a light source according to the present invention refers to peak wavelength, i.e., the wavelength at which the optical spectrum the light emitted by the light source has its maximum.

[0082] When referring to the “blue” light or light within the “blue range”, it is be noted that this corresponds to light within the visible spectrum that is from 380 nm to 500 nm, preferably from 430 nm to 470 nm, more preferably from 440 nm to 460 nm, most preferably of about 450 nm.

[0083] When referring to the “green” light or light within the “green range”, it is be noted that this corresponds to light within the visible spectrum that is from 520 nm to 590 nm, preferably from 540 nm to 570 nm, most preferably of about 555 nm. When referring to the “orange” light or light within the “orange range”, it is be noted that this corresponds to light within the visible spectrum that is from 590 nm to 635 nm, preferably from 590 nm to 600 nm, most preferably of about 595 nm.

[0084] According to a possible embodiment the wavelength of one light source is different from the wavelength of another light source.

[0085] According to possible embodiments, the wavelength of light emitted by one light source being different than the wavelength of light emitted by another light source means that the peak wavelengths of the one light source is different from the peak wavelength of the other light source. According to possible embodiments, there could be substantially no overlap in the optical spectrum of the two light sources, or there could be a small or negligible percentage of overlap at the end part of the optical spectrum. According to possible embodiments, the peak wavelength of the one light source does not lie within the full width at half maximum (FWHM) of the spectrum of the other light source, and that the peak wavelength of the other light source does not lie within the FWHM of the one light source.

[0086] Fig. 4A illustrates a preferred embodiment of the present invention. The aerosolgenerating unit 110 comprises at least two light sources. The at least two light sources comprise a first light source 111 that is configured to emit light in the blue range, and a second light source 112. The second light source 112 is configured to emit light in the green or, alternatively, in the orange range. Additionally, the at least two light sources may comprise a further third light source 113, as illustrated in Fig. 4B. The third light source 113 is configured to emit light outside the blue range, wherein the third light source 113 is configured to emit light in the green range or, alternatively, in the orange range. It is preferred, when three light sources are provided, that the first light source 111 is configured to emit light in the blue range, the second light source 112 is configured to emit light in the green range, and the third light source 113 is configured to emit light in the orange range.

[0087] In the preferred embodiment, the at least two light sources are configured to light such that the emitted lights are incident onto the same portion of the aerosol-generating substrate 210. In the context of the present invention, at least two light sources are configured to emit light onto a same portion of an aerosol-generating substrate 210 when the main emission directions of the at least two light sources intersect within the same portion, or preferably at the surface of that same portion of the aerosolgenerating substrate 210 onto which light from the at least two light sources are incident. Within the context of embodiments shown in Figs. 4A and 4B, this means that the first light source 111 and the second light source 112, as shown in Fig. 4A, or the first light source 111, the second light source 112, and the third light source 113, as shown in Fig. 4B, are oriented such that the main emission directions of the first light source 111 and the second light source 112, or the main emission directions (illustrated as solid lines) of the first light source 111, the second light source 112, and the third light source 113 intersect as described above. However, this arrangement of light sources is not limited to two or three light sources, but is generally applicable to a plurality of light sources such as four or more light sources.

[0088] The type of light source can be chosen depending on the requirements of the aerosolgenerating device too regarding heating performance, energy consumption, spatial constraints within the aerosol-generating device too, size and shape of the aerosolgenerating substrate 210, and other factors known to the person skilled in the art.

[0089] In the preferred embodiment, one or more, or all of the at least two light sources are coherent light sources, such as, for example, a lasers. Lasers, in particular, have a small beam divergence and thus narrow beam that allows heating of the aerosol-generating substrate 210 to be focused on and limited to a precise and well-defined portion of the aerosol-generating substrate 210. This provides improved control over the heating process and allows targeted and selective heating of the aerosol-generating substrate 210. The lasers maybe surface-emitting lasers, such as, for example, vertical cavity surface emitting lasers (VCSEL), photonic crystal surface-emitting lasers (PCSEL), and topological cavity surface emitting lasers (TCSEL). Compared to other types of lasers, such as, for example, edge-emitting laser, surface-emitting lasers are easier to manufacture and install in the aerosol-generating device too. In addition, surfaceemitting lasers require less power, which is particularly advantageous in portable or handheld aerosol-generating devices that have a limited and non-constant constant power supply.

[0090] However, the type of light source is not limited to coherent light sources. Additionally, or alternatively, one or more, or all of the at least two light sources may be noncoherent light sources, such as, for example, such as LEDs, filament bulbs or plasma / flame radiation devices. LEDs, in particular, are energy-efficient and requires less power to operate when compared to coherent light sources, such as, for example, lasers. As described, decreased power consumption is particularly advantageous in portable or handheld devices. As can be seen in Figs. 4A and 4B, the at least two light sources may be arranged within the aerosol-generating device 100 such that their distance to at least one same portion of the aerosol-generating substrate 210, onto which the at least two light sources are configured to emit light, are equal. While Fig. 4A illustrates the aerosol-generating substrate 210 as a rectangular shape, the shape of the aerosol-generating substrate 210 is not limited and may have a circular, spherical, ellipsoidal, or cigarette-like shape, as described above in the contexts of Figs. 2Ato 2B.

[0091] In case the aerosol-generating substrate 210 has a disk-like shape with flat surface on opposite sides of the disk-like shape, as exemplified in Figs. 2B and 3B, the at least two light sources may be arranged to be at a same distance from a portion of one of the two flat surfaces. In case the aerosol-generating substrate 210 has a cylindrical shape emulating a cigarette, as shown in Fig. 2A, the at least two light sources may be arranged to be at a same distance from the base of the aerosol-generating substrate 210 that is inserted into the cavity or chamber 105 of the aerosol-generating device too. Alternatively, the at least two light sources may be arranged to be at a same distance from a curved portion of the lateral surface of the cylindrical shape of a cigarette. In case the aerosol-generating substrate 210 is comprised in an aerosol-generating article 200 in the form of a cartridge, the at least light sources are arranged in the aerosolgenerating device too such that when the aerosol-generating article 200 is attached to the aerosol-generating device too, the at least two light sources are arranged at a same distance from at least one same portion of the aerosol-generating substrate 210 onto which the at least two light source are configured to emit light.

[0092] Since any light source has a non-zero beam divergence, the distance of the light source to the aerosol-generating substrate 210 affects the parameters of beam size, coherence, and intensity of light that is incident on the aerosol-generating substrate 210. If individual light sources of the at least two light sources are arranged at different distances from a same portion of the aerosol-generating substrate 210, differences in the above parameters must be accounted for when setting operational parameters of the individual light sources. For example, due to beam divergence, if a first and a second laser of the same type are arranged at different distances, the beam size incident on the aerosol-generating substrate 210 from the first laser, positioned at a larger distance from the aerosol-generating substrate 210, is larger than the beam size of the second laser that is positioned at a smaller distance from the aerosol-generating substrate 210. As a consequence, even if the first and the second laser are arranged to emit light onto a same portion of the aerosol-generating substrate 210, the area and / or volume of the aerosol-generating substrate 210 that is illuminated by the first laser is larger than the area and / or volume of the aerosol-generating substrate 210 that is illuminated by the second laser, thus leading to non-uniform heating of the aerosolgenerating substrate 210 by the first laser and the second laser. Consequently, when the at least light sources are of a same type of light sources, such as, lasers of a same type, it is therefore preferred to arrange the at least two light sources at a same distance from the aerosol-generating substrate 210, since it minimizes deviations in the above parameters and affords improved control over the heating process.

[0093] It has to be also noted that according to possible embodiments, the light sources of the aerosol generating unit may be provided with collimating components which allows to adjust the beam size. This arrangement may be advantageous when the distance from each of the light sources to the irradiation area is different because it allows to compensate divergence of lights which increases the beams size with an increase in distance from the light source.

[0094] Additionally, or alternatively, as shown in Figs. 5A and 5B, when viewing an outer surface portion of the aerosol-generating substrate 210 onto which the at least two light sources are configured to emit light, from a plan view, the at least light sources may be arranged to emit light onto the portion of the aerosol-generating substrate 210 from different directions, i.e., the emission directions of the at least two light sources are non-parallel to each other. This facilitates the arrangement of the at least two light sources within the spatial constraints of the aerosol-generating device too and allows the at least two light sources to be arranged in close proximity to the aerosol-generating substrate 210 while allowing the at least two light sources to emit light directly onto a same portion of the aerosol-generating substrate 210. This is particularly advantageous for portable or handheld devices. Additionally, or alternatively, the at least two light sources may be arranged, in plan view, on a curved, preferably arced, or even more preferably circular or elliptical line. The arrangement on a circular or elliptical line is particularly advantageous for an aerosol-generating device too that is of an elongated shape with a circular or elliptical base shape, as described in the context of embodiments illustrated in Figs. 2Ato 2B. Additionally, or alternatively, the at least two light sources are arranged such that the lights emitted by the at least two light sources are incident on the same portion of the aerosol-generating substrate 210 from different directions that, when view in plan view, are spaced apart by equal angular distances from each other. This can be achieved by arranging the at least two light sources, when viewed in plan view and based on the point, at which the main emission directions of the at least two light sources intersect, as the origin point, at equal angular distances from each other.

[0095] Additionally, or alternatively, the at least two light sources are arranged such that the lights emitted by the at least two light sources have a same angle of incidence onto the surface of a same portion of the aerosol-generating substrate 210. Since light sources in general have a non-zero beam divergence, parameters such as size and intensity of the emitted lights that are incident onto the portion of the aerosol-generating substrate 210 are dependent on the incidence angle. A larger incidence angle of a light source (relative to the local surface normal) leads to a larger surface area or volume of the aerosol-generating substrate 210 being illuminated by light emitted from the light source than a smaller incidence angle, and thus changing the beam intensity onto the aerosol-generating substrate 210. For example, a light with a circular beam profile that is incident onto a surface at a non-zero incidence angle (relative to the local surface normal) will result not in a circular, but an elliptical illuminated area on the surface of the aerosol-generating substrate 210. By emitting light onto the aerosol-generating substrate 210 at a same incidence angle minimizes differences between the beam intensity distribution of the lights of the at least two sources on the aerosol-generating substrate 210, which is particularly advantageous for light sources of a same type with a same or similar beam profile. This affords more uniform heating of the aerosolgenerating substrate 210 via the at least two light sources and provides improved control over the heating process.

[0096] While Figs. 4A, 4B, 5A, and 5B illustrate an aerosol-generating unit 110 with two light sources or three light sources, the number is light sources is only limited by spatial constraints and / or power supply limitations of the aerosol-generating device too, and the aerosol-generating unit 110 may comprise four or more light sources. In an embodiment, as shown in Figs. 6A and 6B, the aerosol-generating unit 110 may comprise six light sources. While in Fig. 6A, the arrangement of the six light sources is illustrated in relation to a rectangular or disk-shaped aerosol-generating substrate 210, the arrangement described in the following can be applied to any suitable shape of the aerosol-generating substrate 210, such as, for example, spherical, ellipsoidal, or cylindrical aerosol-generating substrates. The aerosol-generating substrates may preferably be aerosol-generating substrates as described in the context of embodiments shown and illustrated in Figs 2A to 5B. Furthermore, the light sources of the embodiment illustrated in Figs. 6A and 6B may preferably be light sources as described above in the context of embodiments illustrated in Figs. 3A to 5B. In the embodiment illustrated in Figs. 6A and 6B, a first light source and a first further light source ma are provided to form a first pair of light sources. The first light source in and the first further light source ma may be arranged on opposite sides of the aerosol-generating substrate 210. Alternatively, the first light source 111 and the first further light source 111a maybe arranged adjacent each other. A second light source 112 and a second further light source 112a maybe provided to form a second pair of light sources. Furthermore, a third light source 113 and a third further light source 113a may be provided to form a third pair of light sources.

[0097] The arrangement of the second light source 112 and the second further light source 112a, and additionally, or alternatively, the arrangement of the third light source 113 and the third further light source 113a may be as described for the first light source 111 and the first further light source 111a. The first light source 111, the second light source 112, and the third light source 113 may be arranged on one side of the aerosolgenerating substrate 210 as described above in the context of embodiments illustrated in Figs. 4A to 5B. The first light source 111, the second light source 112, and the third light source 113 may be arranged with distances to the aerosol-generating substrate 210, and / or with an incidence angle, and / or with an arrangement in plan view as described in the context of embodiments illustrated in Figs. 4A to 5B.

[0098] The first light source 111, the second light source 112, and the third light source 113 may be configured to emit light in a blue range, and / or green range, and / or orange range as described above in the context of embodiments illustrated above in Figs. 3A to 5B. For example, the first light source 111 may be configured to emit light in the blue range the second light source 112 may be configured to emit light in the green range, and the third light source 113 may be configured to emit light in the orange range. The first further light source 111a, the second further light source 112a, and the third further light source 113a may be configured to emit light with a wavelength substantially and respectively corresponding to the wavelength of the light emitted by the first light source 111, the second light source 112, and the third light source 113.

[0099] “Substantially corresponding” means that the peak wavelength of the first light source 111 and / or the second light source 112 and / or the third light source 113 lies, within the FWHM of, respectively, the first further light source 111a, the second further light source 112a, and the third further light source 113a. As shown in Fig. 6A, the six light sources are configured to emit light onto at least one same portion of the aerosolgenerating substrate 210. As described in the context of Figs. 4A and 4B, the six light sources are configured such that the main emission directions of the six emitted lights intersect at a common point within the aerosol-generating substrate 210. Alternatively, the first light source 111, the second light source 112, and the third light source 113 may be configured such that their respective main emission directions intersect on one surface of the aerosol-generating substrate 210, while the first further light source, the second further light source, and the third further light source are configured such that their respective main emission directions intersect at the other, opposite surface of the aerosol-generating substrate 210.

[0100] Alternatively, as shown in Fig. 6B, all six light sources may be arranged on a same side of the aerosol-generating substrate 210. In such case, the first light source 111 maybe arranged to be neighboring the first further light source 11b, the second light source 112 may be arranged to be neighboring the second further light source 112a, and the third light source 113 may be arranged neighboring the third further light source 113a.

[0101] Alternatively, as shown in Fig. 6C, instead of forming a first / second / third pair of light sources using two light sources to emit a first / second / third pair of light beams, a single light source in conjunction with an optical element, such as, for example, a beam splitter 120 can be provided. Instead of providing a first light source 111 and first further light source 111a to form a first pair of light sources to emit a first pair of light beams, a first light source 111 can be provided in conjunction with a beam splitter 120 so that a light beam emitted from the first light source 111 is split into two separate light beams. This allows the generation of a pair of light beams using only a single light source. This configuration can be utilized for any one of the second, and / or third, and / or any further pair of light sources.

[0102] According to a preferred embodiment, the control unit 140 is configured to perform a method in which the at least two light sources are operated in a separated, preferably sequential manner to emit light onto the at least one same portion of the aerosolgenerating substrate 210 during non-overlapping time intervals and thus different time intervals, i.e., only one light source of the at least two light sources is emitting light while the other light sources of the at least two light sources are not emitting light. To this purpose, the control unit 140 is configured to control the beam-on time of the first light source 111, during which the first light source 111 is emitting light, to be nonoverlapping with and thus different from the beam-on time of the second light source 112, during which the second light source 112 is emitting light, and / or to be non- overlapping with and thus different from the beam-on time of the third light source 113, during which the third light source 113 is emitting light.

[0103] Fig. 7 illustrates a possible method of sequentially operating the at least two light sources. While the sequential operation is illustrated for three light sources, it can be applied for only two light sources or more than three light sources. During a puff of a user, which can be detected and measured using appropriate means such as a flow sensor or another suitable sensor, the aerosol-generating unit 110 is configured to perform a light emission sequence. While the light sources comprised by the aerosolgenerating unit 110 can be pre-set to perform a predetermined light emission sequence, according to different possible embodiments the aerosol-generating device too is provided with a control unit 140 that is configured to control operation of the aerosolgenerating unit 110 and the light sources independently from a pre-set or predetermined sequence.

[0104] As an example of a 1-2-3 sequence (herein the expression “1-2-3 sequence” is used to indicate sequence of successive steps generally indicated with numbers 1-2-3), first, as step 1, the control unit 140 controls the first light source 111 to emit light in the blue range. During the first beam-on time tb,on during which the first light source 111 is emitting light, the second light source 112 and the third light source 113 are respectively in the beam-off time during which neither the second light source 112 nor the third light source 113 is emitting light. After the beam-on time of the first light source 111, the control unit 140 controls the first light source 111 to be in the beam-off time, and second, as step 2, subsequently controls the second light source 112 to be in the second beam-on time tg,On during which the second light source 112 is emitting light, and the first light source 111 and the third light source 113 are not emitting light. After the second beam-on time, the control unit 140 controls the second light source 112 to be in the beam-off time, and third, as step 3, subsequently controls the third light source 113 to be in a third beam-on time to,on during which the thirds light source is emitting light, while the first light source 111 and the second light source 112 are in the respective beam-off time. Short pauses between each beam-on time during which no light is emitted at all may be present.

[0105] The applicant has found that many typical aerosol-generating substrate, in particular tobacco substrates, 210 have an increased absorption in the blue range, while smaller portions of the components of the aerosol-generating substrate have an optical absorption spectrum with maxima in the green and orange range. In a further implementation of the device according to the first aspect, aerosolgenerating substrate comprising two or more constituents, at least two of the constituents have different optical absorption spectra, such that they are capable of being heated separately by light of different wavelengths. This different optical absorption spectra among the constituents enables selective heating by the light sources allowing the device to utilize the distinct optical properties of the constituents to achieve selective heating.

[0106] According to an embodiment, the first light source can be tuned to a wavelength that is preferentially absorbed by one constituent, while the second light source can be tuned to a different wavelength that is absorbed by another constituent. The ability to heat different constituents separately provides precise control over the heating process, potentially leading to more efficient aerosol generation and enhanced flavor or nicotine delivery, depending on the constituents involved. Furthermore, this feature may allow for the customization of the aerosol-generating process based on the desired outcome, such as varying the intensity or duration of heating for specific constituents to achieve different aerosol characteristics.

[0107] It is therefore preferable that the beam-on time tb,onof the first light source in that is configured to emit light in the blue range is longer in relation to the beam-on time tg,On or to, on of the second light source 112 that is configured to emit light in the green range or orange range. It is therefore also preferable that, when a third light source 113 is provided, that the beam-on time tb,onof the first light source 111 is longer in relation to the beam-on time tg,onof the second light source 112 that is configured to emit light in the green range, and longer in relation to the beam-on time to,on of the third light source 113 that is configured to emit light in the orange range. The longer beam-on tb,on time of the first light source 111 accounts for the larger portion of the components of the aerosol-generating substrate 210 that have an optical absorption spectrum with a maximum in the blue range and provides sufficient heating of the larger portion of the components via the emitted light in the blue range.

[0108] According to possible embodiments, the beam-on time of the first light source 111 is less than 50% of the duration of a single puff, preferably less than 40%, more preferably between 25% and 45% of the puff duration. The beam-on time of the second light source 112 is less than 15%, preferably less than 10%, more preferably between 5% and 10% of the puff duration. Similarly, the beam-on time of the third light source 113 is less than 15%, preferably less than 10%, more preferably between 5% and 10% of the puff duration.

[0109] According to a possibile embodiment, for an example puff duration of 2.0 seconds, the beam-on time of the first light source 111 is less than 1.0 seconds, preferably less than 0.8 seconds, more preferably between 0.5 seconds and 0.9 seconds. The beam-on time of the second light source 112 is less than 0.3 seconds, preferably less than 0.2 seconds, more preferably between 0.1 seconds and 0.2 seconds. The beam-on time of the third light source 113 is less than 0.3 seconds, preferably less than 0.2 seconds, more preferably between 0.1 seconds and 0.2 seconds.

[0110] According to possible embodiments, the beam-on time of the first light source 111 is between 5 to 15 times longer, preferably between 7 to 13 times longer, more preferably between 9 to 11 times longer than the second beam-on time. In case of three light sources, the beam-on time of the first light source 111 can be between 5 to 15 times longer, preferably between 7 to 13 times longer, more preferably between 9 to 11 times longer than the third beam-on time.

[0111] Additionally, or alternatively, the control unit 140 may be configured to control the aerosol-generating unit 110 to repeat the above-described light emission sequence to ensure uniform heating of the at least one same portion of the aerosol-generating substrate 210 onto which the light sources are configured to emit light. It should be noted that, instead of the sequence order of 1-2-3, wherein successive steps generally indicated with numbers 1-2-3 mean that the step 2 is performed after step 1 and step 3 is performed after step 2, and so on, all permutations of the 1-2-3 order, thus different orders of step 1, step 2 and step 3, can be performed.

[0112] As illustrated in Fig. 7, a sequence can be repeated throughout the duration of a user puff. Alternatively, instead of repeating a same sequence, different sequences can be performed in succession during a user puff. The total length of a sequence is the cycle length tcycie. The control unit 140 maybe configured to adjust a respective cycle length tcycie depending on how many cycles of a sequence should be performed during one user puff.

[0113] To simplify and improve control over the heating process, the light sources of the aerosol-generating unit 110 may be configured to emit light with substantially a same amplitude. This minimizes deviations in heating performance between the light sources and allows the heating performance of the light sources to be controlled via the lengths of respective the beam-on times only.

[0114] While the preferred embodiment described in the context of Fig. 7 is not limited to specific types of light sources, controlling the light sources of the aerosol-generating unit 110 such that respective beam-on times are non-overlapping and thus different is particularly advantageous for coherent light sources, such as, for example lasers. This prevents unwanted interference between the coherent light sources and simplifies the heating process.

[0115] While this disclosure has described certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the scope of this disclosure, as defined by the independent and dependent claims.

[0116] LIST OF REFERENCE SIGNS USED too aerosol-generation device

[0117] 105 cavity / chamber

[0118] 110 aerosol-generation unit

[0119] 111 first light source

[0120] 111a first further light source

[0121] 112 second light source

[0122] 112a second further light source

[0123] 113 third light source

[0124] 113a third further of light source

[0125] 120 beam splitter

[0126] 130 optical element

[0127] 140 control unit

[0128] 150 power source

[0129] 200 aerosol-generating article 210 aerosol-generating substrate tb,on first beam-on time tg,on second beam-on time to, on third beam-on time tcycle cycle period

Claims

Claims for PCT1. An aerosol-generating device comprising: at least two light sources emitting light onto at least one same portion of an aerosol-generating substrate received by the aerosol generation device, for generating an aerosol, wherein a first beam-on time of emitting light from the first light source onto the portion of the aerosol-generating substrate is non-overlapping with a second beam-on time of emitting light from a second light source of the at least two light sources onto the least one same portion of the aerosol-generating substrate.

2. The aerosol-generating device according to claim i, wherein the first light source comprised by the at least two light sources is configured to emit light with a wavelength within a first range of 380 nm to 500 nm, a preferably of 430 nm to 470 nm, more preferably of 440 nm to 460 nm, most preferably of about 450 nm.

3. The aerosol-generating device according to claim 1 or 2, wherein the at least two light sources comprise a first light source configured to emit light with a wavelength within a first range and a second light source configured to emit light with a wavelength within a second range, wherein the first range and the second range are different one from another.

4. The aerosol-generating device according to the preceding claim, wherein the first beam-on time and the second beam-on time are operated in sequence, preferably sequentially alternated.

5. The aerosol-generating device according to any one of the preceding claims, wherein the first beam-on time is longer than the second beam-on time.

6. The aerosol-generating device according to the preceding claim, wherein the first beam-on time is between 5 to 15 times longer, preferably between 7 to 13 times longer, more preferably between 9 to 11 times longer than the second beam-on time.

7. The aerosol-generating device according to any one claims 1 to 6, wherein light from the first light source is emitted at a first amplitude that is substantially the same as the amplitude of the light emitted by the second light source.

8. The aerosol-generating device according to any one of the claims 1 to 7, wherein the at least two light sources further comprise a third light source configured to emit light onto the at least one same portion of the aerosol-generating substrate, wherein a third beam-on time of emitting light from the third light source onto the at least one same portion of the aerosol-generating substrate is nonoverlapping with the first and / or the second beam-on time.

9. The aerosol-generating device according to the preceding claim, wherein the first beam-on time, the second beam-on time, and the third beam- on time are operated in sequence, preferably sequentially alternated, and / or wherein the first beam-on time is longer than the third beam-on time.

10. The aerosol-generating device according to any one of claims 8 to 9, wherein light from the first light source is emitted at a first amplitude that is substantially the same as the amplitude of the light emitted by the third light source.

11. The aerosol-generating device according to any one of claims 1 to 10, wherein one or more of the at least two light sources are coherent light sources.

12. The aerosol-generating device according to any one of claims 1 to 11, wherein one or more of the at least two light sources are non-coherent light sources.

13. The aerosol-generating device according to any one of claims 1 to 12, further comprising a control unit for controlling operational parameters of the at least two light sources, wherein the operational parameters comprise one or more of the beam-one time of one or more of the at least two light sources and an amplitude of the light emitted from one or more of the at least two light sources.14- The aerosol-generating device according to any one of claims 1 to 13, wherein beam-on time is the time duration during which light is emitted, and wherein the first beam-on time is different from the second beam-on time.

15. The aerosol-generating device according to any one of claims 1 to 14, wherein the aerosol-generating substrate comprising two or more constituents, wherein at least two of the constituents have different optical absorption spectra, such that they are capable of being heated separately by light of different wavelengths.

16. The aerosol-generating device according to claim 15, wherein the at least two constituents are heated separately by a first light source and a second light source emitting light at different wavelengths, preferably corresponding to the respective optical absorption spectra of the constituents.

17. An aerosol-generating system comprising the aerosol-generating device of any one of the preceding claims and an aerosol-generating article comprising an aerosolgenerating substrate, wherein the aerosol-generating article is received by the aerosolgenerating device.

18. A method of generating an aerosol, the method comprising generating an aerosol by receiving an aerosol-generating substrate by an aerosol-generating device comprising at least two light sources; generating and emitting light from the at least two light sources onto at least one same portion of the aerosol generating-substrate received by the aerosol generation device, and wherein a first beam-on time of emitting light from the first light source onto the portion of the aerosol-generating substrate is non-overlapping with a second beam- on time of emitting light from a second light source of the at least two light sources onto the portion of the aerosol-generating substrate.

19. The method of claim 18, wherein beam-on time is the time duration during which light is emitted, and wherein the first beam-on time is different from the second beam-on time.

20. The method of claims 18 or 19, wherein the aerosol-generating substrate comprising two or more constituents, wherein at least two of the constituents have different optical absorption spectra, such that they are capable of being heated separately by light of different wavelengths.

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