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CN-122029935-A - Oscillation frequency and electric field strength on load capacitor

CN122029935ACN 122029935 ACN122029935 ACN 122029935ACN-122029935-A

Abstract

The present invention relates to portable and handheld aerosol-generating devices, and in particular to an aerosol-generating device for dielectrically heating an aerosol-forming substrate, the aerosol-generating device comprising a power supply providing a DC supply voltage, an oscillating circuit fed by the power supply, and a dielectric heating element forming a load capacitor arranged for dielectrically heating the substrate, the dielectric heating element being powered by an oscillating voltage from the oscillating circuit. The oscillation frequency is selected to be in excess of 100MHz and less than 1.2GHz, and the DC supply voltage, the oscillation frequency and the electrode arrangement and capacitance values of the load capacitor are selected such that the average electric field strength across the electrodes of the load capacitor is in excess of 10V/mm and less than 200V/mm.

Inventors

  • O. Milonov

Assignees

  • 菲利普莫里斯生产公司

Dates

Publication Date
20260512
Application Date
20241004
Priority Date
20231005

Claims (15)

  1. 1. A portable and handheld aerosol-generating device for dielectrically heating an aerosol-forming substrate, the aerosol-generating device comprising: a power supply that provides a DC supply voltage; an oscillating circuit fed by the power supply, and A dielectric heating element forming a load capacitor arranged for dielectrically heating the substrate, the dielectric heating element being powered by an oscillating voltage from the oscillating circuit, Wherein the oscillation frequency is selected to be in excess of 100MHz and less than 1.2GHz and the DC supply voltage, the oscillation frequency and the electrode arrangement and capacitance values of the load capacitor are selected such that the average electric field strength across the electrodes of the load capacitor is in excess of 10V/mm and less than 200V/mm.
  2. 2. An aerosol-generating device according to claim 1, wherein the oscillation frequency is selected to be between 200MHz and 900MHz and the maximum average electric field strength across the electrodes of the load capacitor is less than 100V/mm, more preferably less than 80V/mm.
  3. 3. An aerosol-generating device according to claim 1 or 2, wherein the capacitance value of the load capacitor comprises the distance between two opposite polarity electrodes of the load capacitor, wherein the closest distance between the two opposite polarity electrodes is selected to be between 0.5mm and 10mm, preferably between 0.7mm and 9mm, more preferably between 1mm and 3 mm.
  4. 4. An aerosol-generating device according to any of the preceding claims, further comprising a controller for controlling the aerosol-generating device such that the substrate is heated.
  5. 5. An aerosol-generating device according to claim 4, wherein the controller is configured such that the matrix is dielectrically heated during a period of time less than 15 minutes at an average dielectric heating power density in the range between 1W/cm 3 to 25W/cm 3 per volume of matrix material.
  6. 6. An aerosol-generating device according to claim 4 or 5, wherein the controller is configured to control the aerosol-generating device such that the effective power loss generated in the load capacitor is in the range 40% to 70%, preferably 60% to 70%, more preferably 65% to 70% compared to all other losses during the target heating phase.
  7. 7. An aerosol-generating device according to any of the preceding claims, wherein the oscillating circuit is a resonant oscillating circuit.
  8. 8. An aerosol-generating device according to claim 7, wherein the load capacitor forms a circuit element of a feedback loop of the resonant tank circuit.
  9. 9. An aerosol-generating device according to claim 8, wherein the load capacitor is an element of a resonant circuit of a feedback loop of the resonant tank circuit.
  10. 10. An aerosol-generating device according to claim 1, wherein the oscillating circuit has a forced oscillation frequency.
  11. 11. An aerosol-generating device according to claim 10, wherein the dielectric heating element forms the load of a switching unit.
  12. 12. An aerosol-generating device according to claim 10 or 11, wherein the oscillating circuit further comprises a quartz-based oscillator to drive the switching unit.
  13. 13. A system, comprising: an aerosol-generating article comprising an aerosol-forming substrate, and An aerosol-generating device according to any one of the preceding claims for dielectrically heating the aerosol-forming substrate.
  14. 14. The system of claim 13, wherein the aerosol-forming substrate comprises a solid material.
  15. 15. A system according to claim 13 or 14, comprising an aerosol-generating device according to claim 8 or 9, wherein the feedback loop has a low impedance, preferably between 500mΩ and 8 Ω, in particular below or about 2 Ω.

Description

Oscillation frequency and electric field strength on load capacitor The present invention relates to an aerosol-generating device, and in particular to an aerosol-generating device configured to heat an aerosol-forming substrate by dielectric heating. The present disclosure also relates to a system comprising the aerosol-generating device. Background Known electrically operated aerosol-generating systems typically heat the aerosol-forming substrate by one or more of conducting heat from the heating element to the aerosol-forming substrate, radiating heat from the heating element to the aerosol-forming substrate, or drawing heated air through the aerosol-forming substrate. Most commonly, heating is achieved by passing an electrical current through the resistive heating element, producing joule heating of the heating element. Induction heating systems have also been proposed in which joule heating occurs due to eddy currents induced in the susceptor heating element. One problem with these heating mechanisms is that they produce non-uniform heating of the aerosol-forming substrate. The portion of the aerosol-forming substrate closest to the heating element is heated faster or to a higher temperature than the portion of the aerosol-forming substrate further from the heating element. Systems have been proposed for heating aerosol-forming substrates in a dielectric manner, which advantageously provide uniform heating of the aerosol-forming substrate. However, known dielectric heating systems are less efficient than induction heating systems and require complex circuitry in order to achieve the necessary voltages and frequencies for dielectric heating of the aerosol-forming substrate. It is desirable to provide a system that heats the aerosol-forming substrate in a dielectric manner with greater efficiency while still being achievable in a compact or handheld system. Disclosure of Invention According to a first aspect, there is provided a portable and handheld aerosol-generating device for heating an aerosol-forming substrate in a dielectric manner. The aerosol-generating device comprises a power supply providing a DC supply voltage, an oscillating circuit fed by the power supply, and a dielectric heating element forming a load capacitor arranged for heating the substrate in a dielectric manner. The dielectric heating element is powered by an oscillating voltage from the oscillating circuit, wherein the oscillating frequency is selected to be more than 100MHz and less than 1.2GHz, and the DC supply voltage, the oscillating frequency and the electrode arrangement and capacitance values of the load capacitor are selected such that the average electric field strength across the electrodes of the load capacitor exceeds 10V/mm and is less than 200V/mm. These frequency ranges and electric field strength ranges may allow for the use of cheaper components and simple circuit designs, and at the same time reduce the risk of electrical breakdown, such that the substrate remains stable. The dielectric heating element may be removably received or integrated within the aerosol-generating device. The oscillation frequency may be selected to be between 150MHz and 1.1GHz, preferably between 175MHz and 1GHz, more preferably between 200MHz and 900 MHz. The maximum electric field strength across the load capacitor (i.e. the maximum average electric field strength across the electrodes of the load capacitor) may be less than 120V/mm, preferably less than 100V/mm, more preferably less than 80V/mm. The oscillation frequency may be selected to be between 200MHz and 900MHz and the maximum electric field strength across the load capacitor may be less than 100V/mm, more preferably less than 80V/mm. The capacitance value of the load capacitor C L may comprise the distance between the two opposite polarity electrodes of the load capacitor C L, wherein the closest distance between the two opposite polarity electrodes may be selected to be between 0.5mm and 10mm, preferably between 0.7mm and 9mm, more preferably between 1mm and 3 mm. These distances may enable the use of simple electrically insulating materials and designs. The two opposite polarity electrodes are electrode plates E 1、E2. The aerosol-generating device may further comprise a controller for controlling the aerosol-generating device such that the substrate is heated. The controller may be configured such that the matrix is dielectrically heated during a period of time less than 15 minutes at an average dielectric heating power density in the range between 1W/cm 3 to 25W/cm 3 per volume of matrix material. This power density range may allow for improved aerosolization of substrates for a variety of different designs, because of the limited size and weight of portable and handheld aerosol-forming devices, and also because of limited battery size and thermal insulation due to portable and handheld designs, it is difficult to obtain heating power density values above 25W/cm 3. On the