Aerosol-generating device with heater comprising a light-emitting element

Abstract

An aerosol-generating device (1) for generating an aerosol from an aerosol-generating substrate (3) comprises a light-emitting element (6) for producing light suitable to generate heat in a portion of the aerosol-generating substrate. The aerosol-generating device further comprises a beam-splitting device (7) arranged for directing two sub-beams onto respective portions of said aerosol-generating substrate (3). Improved vaping experience is provided. Possibly, a tilting mechanism may be used for varying a portion of the aerosol- generating substrate that is heated for successive puffs during a vaping session.

Description

[0001] AEROSOL-GENERATING DEVICE WITH HEATER COMPRISING A LIGHT-

[0002] EMITTING ELEMENT

[0003] The invention relates to an aerosol-generating device that incorporates a heater comprising a light-emitting element. It also relates to a system that comprises such device and an article to be used with it.

[0004] - BACKGROUND OF THE INVENTION -

[0005] Aerosol-generating devices have already been proposed, that implement each a light source as a heater to generate aerosol from a substrate. However, several issues appear when heating the aerosolgenerating substrate through irradiation with light, including heating through laser irradiation.

[0006] A first issue relates to the time necessary to heat the substrate until generating the aerosol in an amount that provides nice taste and vaping sensation to the user from the start of his first puff.

[0007] A second issue relates to the light source irradiating a constant limited portion of the aerosol-generated substrate, therefore causing the substrate to go dry and bum in this portion after some use time while other portions of the aerosol-generating substrate remain unused. In addition, using the whole substrate for generating aerosol requires waiting for heat which originates from the irradiated substrate portion to diffuse within the article that contains the aerosol-generating substrate. Therefore, it is an issue to provide nice vaping experience constantly over the whole use time of a pod of aerosol-generating substrate.

[0008] A third issue relates to heat losses that may occur in an environment of the aerosol-generating substrate within the aerosol-generating device. Indeed, such heat losses cause the time necessary for the substrate to reach temperature value appropriate for generating the aerosol to increase. A fourth issue relates to providing an aerosol-generating device which is based on irradiation-heating but has a low unit cost price.

[0009] Starting from this situation, one object of the present invention consists in improving vaping experience that is provided to a user of an aerosolgenerating device which is based on heating through irradiation.

[0010] In particular, the invention aims at reducing the heating time that is necessary to an irradiation-based heater for generating aerosol in a suitable amount.

[0011] Another object of the invention consists in allowing utilizing completely or almost completely an amount of aerosol-generating substrate that is contained in an article to be used with a device that implements irradiationheating.

[0012] Still another object of the invention consists in avoiding that a radiation beam produced by the light source causes the aerosol-generating substrate to bum locally.

[0013] Still another object of the invention consists in designing the aerosolgenerating device so that it can be assembled easily in an unexpensive way.

[0014] - SUMMARY OF THE INVENTION -

[0015] For meeting at least one of these objects or others, a first aspect of the present invention proposes an aerosol-generating device for generating an aerosol from an aerosol-generating substrate, which device comprises:

[0016] - a chamber for accommodating at least part of, or completely, the aerosol-generating substrate; and

[0017] - a heater configured to heat the aerosol-generating substrate when present in the chamber, in order to generate the aerosol, the heater comprising an optical apparatus that comprises a light-emitting element adapted for producing light suitable to generate heat in a portion of the aerosol-generating substrate. In the context of the invention, light encompasses any radiation with wavelength value suitable for this light to be absorbed by the aerosolgenerating substrate, so that a temperature of this substrate increases. In particular, light may be in the visible or near-infrared range.

[0018] According to the invention, the optical apparatus further comprises a beam-splitting device which is arranged for splitting a light beam produced by the light-emitting element into two sub-beams, and the optical apparatus is arranged for directing both sub-beams onto two respective portions of the aerosol-generating substrate.

[0019] Thus, the beam-splitting device allows heating the aerosol-generating substrate simultaneously within two portions thereof, thereby making it possible to produce enough aerosol after a reduced heating time. Vaping experience is improved in this way even for a first puff after starting of a new vaping session.

[0020] Also heating the aerosol-generating substrate simultaneously within two portions thereof allows utilizing a larger proportion of the substrate present in the chamber and reducing a residual amount of unused substrate that might exist otherwise when implementing irradiation-heating. It also avoids that excessive power irradiated onto a single portion of the aerosol-generating substrate causes this portion to bum.

[0021] Additionally, using a beam-splitting device as proposed by the invention makes it possible to heat the aerosol-generating substrate on two opposite sides thereof, thereby reducing heat losses originating from the substrate itself.

[0022] Preferably, the aerosol-generating device may be arranged so that the portions of the aerosol-generating substrate that receive each a respective one of both sub-beams are separated in a surface of this aerosol-generating substrate.

[0023] In preferred embodiments of the invention, the beam-splitting device may be a semi-transparent mirror. Such type for the beam-splitting device allows easy-to-assemble designs for the aerosol-generating device, thereby reducing its unit cost price. However, other types for the beam-splitting device may be used alternatively, including based on division of the cross-sectional area of the light beam or based on polarization-separation.

[0024] In possible embodiments, the semi-transparent mirror may comprise a transparent substrate plate, for example of silica glass, and a partially reflecting coating arranged on a face of the transparent substrate plate. This coating may comprise at least one among a metal layer, for example an aluminum or titanium layer, a plurality of dielectric layers and a transparent protecting coating.

[0025] In further preferred embodiments of the invention, the optical apparatus may comprise, in addition to the light-emitting element and beam-splitting device, two reflecting mirrors which are each arranged on an optical path of a respective one of the sub-beams between the beam-splitting device and the portion of the aerosol-generating substrate that is heated by this sub-beam. Implementing such reflecting mirrors allows obtaining a compact design for the aerosol-generating device. Advantageously, each reflecting mirror may be based on a thick polished film of aluminum or titanium. By “thick film” is meant a film that is thick enough for being capable of maintaining its shape without being supported by any external element.

[0026] When used, each of the reflecting mirrors may be planar. However, one of these reflecting mirrors may alternatively have a curved reflecting surface, or both reflecting mirrors may have respective curved reflecting surfaces. Such curved reflecting surface enables increasing or narrowing a surface area of the aerosol-generating substrate that receives the corresponding sub-beam. This further reduces the risk of burning the aerosol-generating substrate with excessively focused irradiation power.

[0027] Again when using the reflecting mirrors, at least one of these reflecting mirrors or both may be over-molded in a frame of the optical apparatus or aerosol-generating device, for example a frame of a PEEK-based material, PEEK standing for polyetheretherketone. Unit cost price can be reduced in this way in a further extent, by suppressing a separate assembling step that would be otherwise dedicated to each reflecting mirror. Generally for the invention, the chamber may be bounded by a chamber wall which is transparent to the light produced by the light-emitting element in at least parts of this chamber wall. Then, the optical apparatus may be arranged so that each of the sub-beams passes through a respective one of the transparent parts of the chamber wall. In such case, the chamber wall may be made of fused silica glass or borosilicate glass, so that the chamber wall itself causes almost no absorption in the light power produced by the lightemitting element.

[0028] Advantageously, a thermal insulation may be arranged around the wall chamber, outside of the chamber. Such thermal insulation, for example Microlite®-based or wool-based, reduces heat losses occurring through a casing of the aerosol-generating device.

[0029] According to a possible design, the chamber wall may have two parallel planar faces such that a pod of the aerosol-generating substrate which is shaped as a pad can be accommodated between both planar faces, parallel to these planar surfaces. Indeed, such shape for the pod of aerosol-generating substrate allows reducing unused residual substrate portions, in particular when heated from both sides. Then, the optical apparatus may advantageously be further arranged so that each of the sub-beams passes through a respective one of the planar faces of the chamber wall.

[0030] According to a preferred design for the invention aerosol-generating device, it may have a proximal end from which a user thereof inhales the aerosol, and a distal end opposed to the proximal end, with a longitudinal direction of the aerosol-generating device oriented from the distal end to the proximal end. Then, the following features may be implemented:

[0031] - the light-emitting element may be located at an end of the optical apparatus that is opposed to the proximal end of the aerosolgenerating device;

[0032] - the light-emitting element may be oriented so as to produce the light beam with an emission angle relative to the longitudinal direction, and preferably this emission angle may be comprised between 10° (degree) and 80°, more preferably between 10° and 30°;

[0033] - the chamber may be located between the beam-splitting device and the proximal end of the aerosol-generating device; and

[0034] - the beam-splitting device may be located between the chamber and the light-emitting element in projection on the longitudinal direction.

[0035] Then, the emission angle of the light-emitting element may be such that each of both sub-beams originating from the beam-splitting device bypasses a bottom end of the chamber opposed to the proximal end of the aerosol-generating device, while propagating towards a respective one of the reflecting mirrors.

[0036] With such preferred design and when the beam-splitting device is a semi-transparent mirror, this semi-transparent mirror may be parallel to the longitudinal direction.

[0037] Also possibly with such preferred design, each of the reflecting mirrors may be parallel to the longitudinal direction or may have a center-tangential plane which is parallel to the longitudinal direction.

[0038] Also possibly with the above-recited preferred design, the light-emitting element may be fastened to a planar support, for example a printed circuit board, which is internal to the aerosol-generating device, and this planar support may be parallel to the longitudinal direction. Such mounting for the light-emitting element on a longitudinally arranged planar support reduces assembly costs for the aerosol-generating device.

[0039] Again generally for the invention, the light-emitting element may be of a vertical-cavity surface-emitting laser type, known as VCSEL-type, or a topological-cavity surface-emitting laser type, known as TCSEL-type. Such laser-emitting elements suit in particular because they can output enough light power, for obtaining reduced heating time until enough aerosol is produced.

[0040] A second aspect of the invention proposes an aerosol-generating system that comprises an aerosol-generating device according to the first invention aspect, and an article that comprises the aerosol-generating substrate and that is suitable for being accommodated in the chamber of the aerosol-generating device. In particular, the article may have a pad shape.

[0041] A third aspect of the invention, which is independent from the preceding ones, and / or may be combined with the preceding ones - in particular features disclosed herein with respect to the third aspect can be combined with the first aspect and / or the second aspect -, proposes an aerosol-generating device for generating an aerosol from an aerosol-generating substrate, which device comprises:

[0042] - a chamber for accommodating at least part of, or completely, the aerosol-generating substrate; and

[0043] - a heater configured to heat the aerosol-generating substrate when present in the chamber, in order to generate the aerosol, the heater comprising an optical apparatus that comprises a light-emitting element adapted for producing light suitable to generate heat in a portion of the aerosol-generating substrate, in which the optical apparatus further comprises a tilting mechanism arranged for varying a center propagation direction of the light produced by the lightemitting element. In addition, the heater is arranged so that variation of the center propagation direction causes an impingement location of the light on the aerosol-generating substrate to vary, thereby making a portion of this aerosolgenerating substrate that is heated for producing the aerosol to change.

[0044] Implementing a tilting mechanism according to this third invention aspect also allows reducing a residual proportion of the aerosol-generating substrate that remains unused at the end of a vaping session. It can also reduce the risk of burning part of the aerosol-generating substrate by moving the heated portion in the surface of the aerosol-generating substrate.

[0045] Possibly, the tilting mechanism may include a tilting mirror which is arranged on a path of the light downstream of the light-emitting element.

[0046] But preferably, the tilting mechanism may be arranged intermediate between the light-emitting element and a part of the aerosol-generating device that is fixed relative to the aerosol-generating substrate, so that activation of the tilting mechanism makes the light-emitting element to rotate. More simple assembly of the aerosol-generating device can be achieved in this way. Then, the tilting mechanism may comprise a base part and a movable part which are configured for rotating with respect to each other. The base part may be fixed relative to the aerosol-generating substrate and the light-emitting element may be secured to the movable part.

[0047] Generally for the third invention aspect, a type of the tilting mechanism may be selected in a list that comprises motor actuators, in particular stepper motor actuators, microelectromechanical system actuators, commonly known as ME MS -based actuators, linear actuators, in particular comb-drive actuators, thermal actuators, in particular shape-memory alloy actuators and bimetallic- strip actuators, and piezoelectric-based actuators.

[0048] Also generally for the third invention aspect, the aerosol-generating device may advantageously have one or several of the following optional additional features which can be used independently from one another, or in combination of two or more of them:

[0049] - the tilting mechanism may be adapted so that a variation range that is effective for an orientation of the center propagation direction has an extent of at least 2°, preferably at least 3°;

[0050] - the tilting mechanism may be further adapted so that the extent of the variation range that is effective for the orientation of the center propagation direction is at most 6°, preferably at most 5°;

[0051] - the tilting mechanism may be further adapted so that the extent of the variation range that is effective for the orientation of the center propagation direction is about 4°;

[0052] - the aerosol-generating device may further comprise an airpath arranged for air to flow along a surface of the aerosol-generating substrate when the aerosol-generating device is used. Then, the heater may be configured for, when the aerosol-generating substrate is used for a first time in a vaping session, controlling the tilting mechanism so that the impingement location of the light on the aerosol-generating substrate is first close to a first end of the aerosol-generating substrate that is situated downstream along the airpath, and then moved during the vaping session toward a second end of the aerosol-generating substrate that is shifted upstream along the airpath relative to the first end. This avoids that the heated air loaded with aerosol flows next to a not-yet heated substrate portion and may alter this latter, thereby keeping the not-yet heated substrate portion unaltered for later use;

[0053] - the light-emitting element may be of a vertical-cavity surface-emitting laser type, known as VCSEL-type, or a topological-cavity surfaceemitting laser type, known as TCSEL-type;

[0054] - the light-emitting element may be adapted for producing light in the visible or near-infrared range; and

[0055] - the optical apparatus may further comprise a beam-splitting device arranged for splitting a light beam produced by the light-emitting element into two sub-beams, and this optical apparatus may be arranged for directing both sub-beams onto two respective portions of the aerosol-generating substrate. In particular, the beam-splitting device may be a semi-transparent mirror.

[0056] When a beam-splitting device is used in combination with the third invention aspect, the optical apparatus may further comprise two reflecting mirrors, which are each arranged on an optical path of a respective one of the sub-beams between the beam-splitting device and the portion of the aerosolgenerating substrate that is heated by this sub-beam. Then, the aerosolgenerating device may have a proximal end from which a user thereof inhales the aerosol, and a distal end opposed to the proximal end, with a longitudinal direction of the aerosol-generating device oriented from the distal end to the proximal end. With such configuration, the following additional features may be implemented, which can be used independently from one another, or in combination of two or more of them: - the light-emitting element may be located at an end of the optical apparatus opposed to the proximal end of the aerosol-generating device;

[0057] - the light-emitting element may be oriented so as to produce the light beam with an emission angle relative to the longitudinal direction, and preferably this emission angle may be comprised between 10° and 80°, more preferably between 10° and 30°;

[0058] - the chamber may be located between the beam-splitting device and the proximal end of the aerosol-generating device;

[0059] - the beam-splitting device may be located between the chamber and the light-emitting element in projection on the longitudinal direction;

[0060] - the emission angle of the light-emitting element may be such that each of both sub-beams originating from the beam-splitting device bypasses a bottom end of the chamber opposed to the proximal end of the aerosol-generating device, while propagating toward a respective one of the reflecting mirrors; and

[0061] - further optionally in addition to the above-features: each of the reflecting mirrors may be parallel to the longitudinal direction, or have a center-tangential plane which is parallel to this longitudinal direction; and the light-emitting element may be fastened via the tilting mechanism to a planar support which is internal to the aerosol-generating device, for example a printed circuit board, and this planar support may be parallel to the longitudinal direction. In such case, the beam-splitting device may be rigidly connected to the planar support, and the reflecting mirrors may be over-molded in a frame of the device.

[0062] Generally for the third invention aspect, the chamber may be bounded by a chamber wall which is transparent to the light produced by the lightemitting element in at least parts of this chamber wall. Then, when the optical apparatus comprises a beam-splitting device, such optical apparatus may be arranged so that each of the sub-beams passes through a respective one of the transparent parts of the chamber wall. The chamber wall may be made of fused silica glass or borosilicate glass, or may be provided with openings or windows adapted for the light originating from the light-emitting element to pass through for all impingement locations of the light on the aerosol-generating substrate. The chamber out of the openings or windows may be of PEEK, ceramic, stainless steel... The chamber wall may have two parallel planar faces such that a pod of the aerosol-generating substrate which is shaped as a pad can be accommodated between both planar faces, parallel to these planar faces. In addition, the optical apparatus may be further arranged so that each of the sub-beams passes through a respective one of the planar faces of the chamber wall.

[0063] The advantages mentioned earlier in connection with the first invention aspect also apply to the present third invention aspect when relating to similar features of the aerosol-generating device.

[0064] A fourth aspect of the invention proposes an aerosol-generating system that comprises an aerosol-generating device according to the third invention aspect, and an article that comprises the aerosol-generating substrate and that is suitable for being accommodated in the chamber of the aerosol-generating device. Again, the article may have a pad shape.

[0065] These and other features of the invention will be now described with reference to the appended figures, which relate to preferred but not-limiting embodiments of the invention.

[0066] - BRIEF DESCRIPTION OF THE DRAWINGS -

[0067] Figure 1 shows an aerosol-generating device according to a possible embodiment of the present invention.

[0068] Figure 2 is an enlargement of part of Figure 1 , focused on an optical apparatus which is comprised in the aerosol-generating device and wherein the aerosol-generating substrate is not arranged inside the chamber. Figure 3 shows an alternative embodiment of reflecting mirrors which may be used in the aerosol-generating device of Figure 1 .

[0069] Figure 4a shows a possible assembly internal to the aerosol-generating device of Figure 1 .

[0070] Figures 4b is an enlargement of part of Figure 4a.

[0071] Figure 5 corresponds to Figure 2 but illustrates operation of a tilting mechanism which is comprised in the assembly of Figure 4a.

[0072] For clarity sake, element sizes which appear in these figures do not correspond to actual dimensions or dimension ratios. Also, same reference numbers which are indicated in different ones of these figures denote identical elements of elements with identical function.

[0073] - DETAILED DESCRIPTION OF THE INVENTION -

[0074] Referring to Figures 1 and 2, an aerosol-generating device 1 may have a general elongated shape parallel to a longitudinal direction L. It extends between a proximal end PE and a distal end DE, and the longitudinal direction L is oriented from the distal end DE toward the proximal end PE. The aerosolgenerating device 1 is enclosed within a casing 100. It is possible, but not necessarily, that the device 1 is provided with a mouthpiece 101 at the proximal end PE for a user to inhale aerosol therethrough. Such mouthpiece 101 may be removable from the casing 100, in particular for loading a pod of aerosolgenerating substrate 3 into a dedicated chamber 9 internal to the device 1. However, implementing such mouthpiece 101 can be avoided when an article that contains the aerosol-generating substrate 3 is designed so as to partially extend out of the casing 100 when loaded into the device 1. Reference number 102 denotes a rechargeable power source, commonly called battery, which is internal to the device 1 .

[0075] The chamber 9 may be formed by a chamber wall 90 designed for accommodating a pod of the aerosol-generating substrate 3 that is shaped as a pad. In such case, the chamber wall 90 may have two opposed planar faces 91 and 92 (see Figure 2) which are parallel to each other and to the longitudinal direction L. The faces 91 and 92 are apart from each other so that the pod can be slid into the chamber 9 from the proximal end PE by the user, for example after removal of the mouthpiece 101. For the heating operation that will be explained below, the faces 91 and 92 of the chamber wall 90 are transparent to a radiation, also called light, produced by a light-emitting element 6. This lightemitting element 6 is suitable for its emitted light to be absorbed by the aerosolgenerating substrate 3 after having passed through the chamber faces 91 and 92. For example, the light-emitting element 6 produces light in the near-infrared range. Preferably, the chamber wall 90 may be out of fused silica glass or borosilicate glass in the faces 91 and 92, for causing almost no light absorption. For cost-saving purpose, the whole chamber wall 90 may be advantageously out of fused silica glass or borosilicate glass.

[0076] For heating the aerosol-generating substrate 3 when the pod is inside the chamber 9, the device 1 comprises an optical apparatus 5 designed for directing light into the chamber 9 through both faces 91 and 92. Such optical apparatus 5 comprises the light-emitting element 6, a beam-splitting device 7 and also optional reflecting mirrors 81 and 82.

[0077] The light-emitting element 6 may be of laser type, such as verticalcavity surface-emitting laser type, known as VCSEL-type, or topological-cavity surface-emitting laser type, known as TCSEL-type. It may be a laser diode. During operation of the optical apparatus 5 for heating the aerosol-generating substrate 3, the light-emitting element 6 produces a light beam B0 (see for example Figure 2) with center emission direction denoted ED. In a usual way, center emission direction denotes the mean propagation direction of the light beam B0 as produced by the light-emitting element 6, although this light beam may spread angularly from this mean emission direction, corresponding to its divergence angle.

[0078] In the configuration of the device 1 that is described here for exemplifying purpose, the beam-splitting device 7 is a semi-transparent mirror which is planar and oriented parallel to the chamber faces 91 and 92. It is located between the light-emitting element 6 and a bottom end of the chamber 9 opposite the proximal end PE, preferably with a transverse position which is substantially in line with a median plane of the chamber 9. Possibly, such semitransparent mirror may comprise a transparent substrate plate 70 coated on one face thereof with a metal layer 71. The transparent substrate plate 70 may be of silica glass and the metal layer 71 may be of aluminium or titanium, for example. Possibly, the metal layer 71 may be replaced with other partially reflecting coatings, for example based on a stack of dielectric layers. Also possibly, the metal layer 71 or other partially reflecting coating that is used alternatively may be covered with a transparent protecting coating (not represented) on a side opposite the transparent substrate plate 70. The metal layer 71 of other partially reflecting coating that is used alternatively is designed so as to reflect a part of the light beam B0 and simultaneously transmit another part of the light beam B0. The reflection and transmission ratios of the semitransparent mirror 7 may advantageously both above 48%.

[0079] The light-emitting element 6 may be oriented so that the center emission direction ED of the light beam B0 forms an angle a with the longitudinal direction L, which is comprised between 10° and 80°, preferably between 10° and 30°. With such orientation, two sub-beams B1 and B2 produced by the beam-splitting device 7 from the light beam B0 propagate obliquely relative to the longitudinal direction L so as to bypass the bottom end of the chamber wall 90 each on a respective side, in direction of the proximal end PE. In the figures with the beam-splitting device 7 of semi-transparent mirror type, sub-beam B1 corresponds to the part of the light beam B0 that is transmitted through the semi-transparent mirror and sub-beam B2 corresponds to the other part of the light beam B0 that is reflected.

[0080] The reflecting mirrors 81 and 82 may be formed each by a polished reflecting metal plate, with reflection ratio preferably higher than 95%. They are arranged substantially parallel to the chamber faces 91 and 92 on either side of the chamber 9 so that the mirror 81 reflects sub-beam B1 towards the chamber face 91 , and the mirror 82 reflects sub-beam B2 towards the chamber face 92. Hence, sub-beam B1 passes through the chamber face 91 and impinges onto one face of the aerosol-generating substrate 3 for heating it. Simultaneously and similarly, sub-beam B2 passes symmetrically through the chamber face 92 and impinges onto the other face of the aerosol-generating substrate 3 also for heating it but from opposite side. Advantageously, each of the mirrors 81 and 82 may be over-molded in a lining frame 10 of the optical apparatus 5. Easy assembly of both mirrors 81 and 82 into the device 1 can thus be obtained in a one-step operation. The lining frame 10 may be out PEEK for heat-resistance purpose. A thermal insulation 11 may also be inserted between the lining frame 10 and the casing 100, for example based on Microlite® or wool. More generally, such insulation may be located around the wall chamber 90, outside the chamber 9, for reducing heat losses originating from the heated aerosolgenerating substrate 3.

[0081] Figure 2 shows a device configuration as just described when using planar reflecting mirrors 81 and 82.

[0082] It is possible using curved reflecting mirrors 81 and 82 for example as shown in Figure 3. In this figure, reflecting mirrors 81 and 82 are convex mirrors which makes the impingement areas of the sub-beams B1 and B2 on the aerosol-generating substrate 3 larger. Improved usage of the pod of the aerosol-generating substrate 3 can be obtained in this way. Using concave reflecting mirrors 81 and 82 is possible alternatively for narrowing the subbeam impingement areas on the aerosol-generating substrate 3.

[0083] As shown in Figure 4a, it may be advantageous providing the semitransparent mirror 7 and the light-emitting element 6 preassembled with a planar support such as a printed circuit board 12, commonly known as PCB. To this purpose, a preassembling frame 13, for example made of PEEK, may be implemented for supporting the semi-transparent mirror 7 and the printed circuit board 12 in suitable relative positions. To this end, the preassembling frame 13 may be over-molded onto the semi-transparent mirror 7, with two protruding arms 13a and 13b which maintain the semi-transparent mirror 7 along lateral edges of this latter. The light-emitting element 6 is secured to the printed circuit board 12 so that the center emission direction ED of the light beam B0 is oriented in use toward a center portion of the semi-transparent mirror 7. Thus, the preassembling frame 13 with semi-transparent mirror 7, the printed circuit board 12 and the light-emitting element 6 can be handled as a one-piece element for insertion into the casing 100 of the aerosol-generating device 1. Advantageously, the preassembling frame 13 may be designed so that the printed circuit board 12 is maintained parallel to the longitudinal direction L within the final device 1 .

[0084] Figure 4b shows a possible mounting method for the light-emitting element 6 on the printed circuit board 12. The light-emitting element 6 is secured to the printed circuit bord 12 using an intermediate tilting mechanism 60. This tilting mechanism 60 may comprise a base part 61 which is rigidly connected to the printed circuit board 12 on the one hand, and a movable part 62 which is rigidly connected to the light-emitting element 6 on the other hand. The base part 61 and movable part 62 are combined with each other so that the light-emitting element 6 can be tilted in a controlled manner for varying the angle a of the center emission direction ED relative to the longitudinal direction L. For example, the tilting mechanism 60 may be of motor-actuator type, with the base part 61 incorporating a coil stator and the movable part incorporating a permanent magnet. Reference number 63 in Figure 4a denote wirings for connecting the tilting mechanism 60 to a controller (not shown) located on the printed circuit board 12, and reference number 64 denote flexible wires dedicated to supplying the light-emitting element 6 with suitable electrical power from the battery 102, using another controller (not shown) also located on the printed circuit board 12. Operation of the tilting mechanism 60 with several values for angle a is illustrated in Figure 5. During inhaling by the user through the aerosol-generating device 1 , air flows on both sides of the aerosolgenerating substrate 3, between this latter and the chamber faces 91 and 92 as indicated by the arrows AP. Airflow direction in these airpath segments is oriented similar to the longitudinal direction L, towards the mouthpiece 101. Preferably, the variation range of angle a may be of about 4°, for example from 18° to 22° for a-values, and varying a makes the impingement area of each sub-beam B1 , B2 to move on the surface of the aerosol-generating substrate 3. Preferably again, angle a may be controlled to increase during a vaping session so that the aerosol-generating substrate 3 is first heated closest to the proximal end PE of the device 1 , and then heated in areas that are progressively shifted toward the distal end DE, as indicated by the arrows Aa in Figure 5. This ensures that hot air does not flow in contact with areas of the aerosol-generating substrate 3 that have not yet been heated by the subbeams B1 and B2. In this way, these not-yet areas of the substrate 3 remain unspoilt for generating aerosol later in the vaping session. Progressively increasing angle a between successive puffs makes all the puffs in the vaping session provide nice taste to the user.

[0085] Implementing a tilting mechanism according to the invention is not limited to combination with a beam-splitting device. It is thus reminded that implementing any tilting mechanism within the optical apparatus of an aerosolgenerating device which is based on irradiation-heating forms an invention aspect separate from using a beam-splitting device.

Claims

C L A I M S1. An aerosol-generating device (1 ) for generating an aerosol from an aerosol-generating substrate (3), comprising:- a chamber (9) for accommodating the aerosol-generating substrate (3); and- a heater configured to heat the aerosol-generating substrate (3) when present in the chamber (9), in order to generate the aerosol, the heater comprising an optical apparatus (5) that comprises a light-emitting element (6) adapted for producing light suitable to generate heat in a portion of said aerosol-generating substrate, wherein the optical apparatus (5) further comprises a beam-splitting device (7) arranged for splitting a light beam (BO) produced by the light-emitting element (6) into two sub-beams (B1 , B2), and said optical apparatus being arranged for directing both sub-beams onto two respective portions of the aerosolgenerating substrate (3).

2. The aerosol-generating device (1 ) according to claim 1 , arranged so that the portions of the aerosol-generating substrate (3) that receive each a respective one of both sub-beams (B1 , B2) are separated in a surface of said aerosol-generating substrate.

3. The aerosol-generating device (1 ) according to claim 1 or 2, wherein the beam-splitting device (7) is a semi-transparent mirror.

4. The aerosol-generating device (1 ) according to claim 3, wherein the semi-transparent mirror comprises a transparent substrate plate (70) and a partially reflecting coating (71 ) arranged on a face of the transparent substrate plate, the coating comprising at least one among a metal layer, a plurality of dielectric layers and a transparent protecting coating.

5. The aerosol-generating device (1 ) according to one of the preceding claims, wherein the optical apparatus (5) further comprises two reflectingmirrors (81 , 82), which are each arranged on an optical path of a respective one of the sub-beams (B1 , B2) between the beam-splitting device (7) and the portion of the aerosol-generating substrate (3) that is heated by said sub-beam.

6. The aerosol-generating device (1 ) according to claim 5, wherein at least one of the reflecting mirrors (81 , 82) has a curved reflecting surface, or both reflecting mirrors have respective curved reflecting surfaces.

7. The aerosol-generating device (1 ) according to claim 5 or 6, wherein at least one of the reflecting mirrors (81 , 82) or both is (are) over-molded in a frame (10) of the optical apparatus (5) or aerosol-generating device, for example a frame of a material based on polyetheretherketone.

8. The aerosol-generating device (1 ) according to one of the preceding claims, wherein the chamber (9) is bounded by a chamber wall (90) which is transparent to the light produced by the light-emitting element (6) in at least parts of said chamber wall, and the optical apparatus (5) is arranged so that each of the sub-beams (B1 , B2) passes through a respective one of the transparent parts of the chamber wall.

9. The aerosol-generating device (1 ) according to claim 8, wherein the chamber wall (90) is made of fused silica glass or borosilicate glass.

10. The aerosol-generating device (1 ) according to claim 8 or 9, wherein the chamber wall (90) has two parallel planar faces (91 , 92) such that a pod of the aerosol-generating substrate (3) which is shaped as a pad can be accommodated between both planar faces, parallel to said planar surfaces.11 . The aerosol-generating device (1 ) according to claim 10, wherein the optical apparatus (5) is further arranged so that each of the sub-beams (B1 , B2) passes through a respective one of the planar faces (91 , 92) of the chamber wall (90).

12. The aerosol-generating device (1 ) according to one of claims 5 to 11 , having a proximal end (PE) from which a user of said aerosol-generatingdevice inhales the aerosol, and a distal end (DE) opposed to the proximal end, with a longitudinal direction (L) of said aerosol-generating device oriented from said distal end to said proximal end, and wherein the light-emitting element (6) is located at an end of the optical apparatus (5) opposed to the proximal end (PE) of the aerosol-generating device (1 ); the light-emitting element (6) is oriented so as to produce the light beam (BO) with an emission angle (a) relative to the longitudinal direction (L), preferably the emission angle (a) relative to the longitudinal direction (L) is comprised between 10° and 80°, more preferably between 10° and 30°; the chamber (9) is located between the beam-splitting device (7) and the proximal end (PE) of the aerosol-generating device (1 ); and the beam-splitting device (7) is located between the chamber (9) and the light-emitting element (6) in projection on the longitudinal direction (L), and wherein the emission angle (a) of the light-emitting element (6) is such that each of both sub-beams (B1 , B2) originating from the beam-splitting device (7) bypasses a bottom end of the chamber (9) opposed to the proximal end (PE) of the aerosol-generating device (1 ), while propagating towards a respective one of the reflecting mirrors (81 , 82).

13. The aerosol-generating device (1 ) according to claim 12 and claim 3 or 4, wherein the semi-transparent mirror is parallel to the longitudinal direction (L).

14. The aerosol-generating device (1 ) according to claim 12 or 13, wherein each of the reflecting mirrors (81 , 82) is parallel to the longitudinal direction (L) or has a center-tangential plane which is parallel to said longitudinal direction.

15. The aerosol-generating device (1 ) according to one of the preceding claims, wherein the optical apparatus (5) further comprises a tilting mechanism (60) arranged for varying a center propagation direction of the light produced bythe light-emitting element, preferably the tilting mechanism comprises a base part (61 ) and a movable part (62) which are configured for rotating with respect to each other, more preferably the base part is fixed relative to the aerosolgenerating substrate and the light-emitting element is secured to the movable part.

16. The aerosol-generating device (1 ) according to one of the preceding claims, wherein the light-emitting element (6) is of a vertical-cavity surfaceemitting laser type or a topological-cavity surface-emitting laser type.

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