Mist generator and cosmetic device

Abstract

 A mist generator (3) provided with an oscillation membrane (12) including a porous atomization portion (11). A liquid supply (29) supplies liquid (L) to the atomization portion (11). An oscillation generator (13; 31) oscillates the oscillation membrane (12) and atomizes the liquid supplied to the atomization portion (11). A liquid film eliminator eliminates a liquid film (LF) from a mist discharge surface (12a) of the oscillation membrane (12) by oscillating the oscillation membrane.

Description

[0001] The present invention relates to a mist generator and a cosmetic device.

[0002] A known mist generator oscillates a porous oscillation membrane, which includes a plurality of pores, to atomize liquid in the pores and generate mist. Japanese Laid-Open Patent Publication No. 4-207800 describes a mist generator including a ring-shaped piezoelectric oscillator and an oscillation membrane, which is joined with the piezoelectric oscillator so as to cover a central opening of the piezoelectric oscillator. The piezoelectric oscillator efficiently oscillates the oscillation membrane, which includes an atomization portion provided with a plurality of pores. The atomization portion covers the central opening of the piezoelectric oscillator.

[0003] Liquid, which is supplied to the oscillation membrane, may permeate through the pores and form a liquid film covering a mist discharge surface of the oscillation membrane. When the oscillation membrane oscillates under this situation, the discharge of mist may become unstable.

[0004] It is an object of the present invention to provide a mist generator and a cosmetic device that eliminate a liquid film from a mist discharge surface and stabilizes mist discharge.

[0005] One aspect of the present invention is a mist generator provided with an oscillation membrane including a porous atomization portion. A liquid supply supplies liquid to the atomization portion. An oscillation generator oscillates the oscillation membrane and atomizing the liquid supplied to the atomization portion. A liquid film elimination mode eliminates a liquid film from a mist discharge surface of the oscillation membrane by oscillating the oscillation membrane.

[0006] Preferably, the liquid film elimination mode oscillates the oscillation membrane with increased oscillation energy.

[0007] Preferably, the oscillation generator includes a piezoelectric oscillator that generates oscillation having an amplitude and/or frequency that is in accordance with the level of input power, and the liquid film elimination mode increases the input power supplied to the piezoelectric oscillator.

[0008] Preferably, the oscillation generator includes a piezoelectric oscillator that generates oscillation having an amplitude and/or frequency that is in accordance with the level of input power, and the liquid film elimination mode repeats precipitous increase and decrease of the input power supplied to the piezoelectric oscillator.

[0009] Preferably, the liquid film elimination mode oscillates the oscillation membrane in a manner that differs from when the liquid is atomized.

[0010] Preferably, the liquid film elimination mode oscillates the oscillation membrane with a frequency that differs from that when the liquid is atomized.

[0011] Preferably, the liquid film elimination mode oscillates the oscillation membrane with a low frequency.

[0012] Preferably, the liquid film elimination mode generates oscillation having a waveform obtained by superimposing oscillation that eliminates the liquid film on oscillation that atomizes the liquid.

[0013] Preferably, the liquid film elimination mode is executed when the mist generator is activated.

[0014] A further aspect of the present invention is a cosmetic device including the mist generator of the above aspect.

[0015] Another aspect of the present invention is a control circuit for controlling a mist generator that oscillates an oscillation membrane and atomizes liquid supplied to a liquid reception surface of the oscillation membrane and discharges the atomized liquid from a mist discharge surface of the oscillation membrane. The control circuit includes a memory for storing a first input power setting value, which indicates first input power that generates oscillation suitable for atomizing the liquid, and a second input power setting value, which indicates second input power that generates oscillation suitable for eliminating a liquid film from the mist discharge surface. A normal mode oscillates the oscillation membrane in accordance with the first input power setting value. A liquid film elimination mode oscillates the oscillation membrane in accordance with the second input setting value. The control circuit executes the liquid film elimination mode to eliminate the liquid film during a controlled time period immediately after the mist generator is activated and executes the normal mode to discharge mist by controlling the input power in accordance with the first input power setting value after executing the liquid film elimination mode.

[0016] The present invention provides a mist generator and a cosmetic device that eliminate a liquid film from a mist discharge surface and stabilize mist discharge.

Fig. 1 is a perspective view showing a cosmetic device;

Fig. 2 is a front view showing a mist generator;

Fig. 3 is a cross-sectional view of the mist generator;

Fig. 4 is a cross-sectional view of a pore;

Fig. 5 is a diagram showing the operation of the mist generator;

Fig. 6 is a cross-sectional view schematically showing the mist generator in a housing;

Fig. 7 is a schematic diagram showing a liquid film formed on a mist discharge surface;

Fig. 8 is a waveform diagram of an input power in a liquid film elimination mode, a shift mode, and a normal mode in a first embodiment;

Fig. 9 is a waveform diagram of an input power in a liquid film elimination mode, a shift mode, and a normal mode in a second embodiment;

Fig. 10 is a waveform diagram of a liquid film elimination mode in a third embodiment;

Fig. 11 is a schematic diagram showing a mist generator in a fourth embodiment;

Fig. 12 is a waveform diagram of an input power in a liquid film elimination mode, a shift mode, and a normal mode in a further example; and

Fig. 13 is a waveform diagram of an input power in a liquid film elimination mode and a normal mode in another embodiment.

First Embodiment

[0017] A mist generator according to a first embodiment of the present invention will now be described.

[0018] Referring to Fig. 1, a cosmetic device 1 includes a mist generator 3, which atomizes a liquid, such as a cosmetic liquid or water, and generates mist. The mist generator 3 is controlled by a control circuit 4. The mist generator 3 and the control circuit 4 are accommodated in a housing 2, which has a side wall 2a including a mist discharge port 5. The mist generated by the mist generator 3 is discharged through the mist discharge port 5 and out of the housing 2.

[0019] In the illustrated example, the cosmetic device 1 (the mist generator 3) is of a portable type. The housing 2 may be cylindrical and include, for example, a grip 6, which has a relatively large diameter. The mist discharge port 5 is located at a position remote from the grip 6, for example, at a position proximal to the upper end of the housing 2. A cover 7, which is movable in the axial direction of the housing 2, is attached to the side wall 2a of the housing 2. The cover 7 is movable between positions where it closes and opens the mist discharge port 5. The cover 7 may have the form of a curved plate or a tube.

[0020] In an embodiment, the cover 7 also functions as an activation switch of the mist generator 3. For example, the mist generator 3 may be activated when the cover 7 is moved to a position where it opens the mist discharge port 5 and deactivated when the cover 7 is moved to a position where it closes the mist discharge port 5.

[0021] When using the cosmetic device 1, a user holds the grip 6, moves the cover 7 to the opening position, and directs the mist discharge port 5 toward the portion of treatment, such as the face, so that mist strikes the portion of treatment. The mist has a cosmetic effect in which it moisturizes the skin.

[0022] Referring to Figs. 2 and 3, the mist generator 3 includes an oscillation membrane 12 and a piezoelectric oscillator 13. The oscillation membrane 12 includes a porous atomization portion 11. A plurality of pores 10 are formed in the atomization portion 11. The piezoelectric oscillator 13 oscillates the oscillation membrane 12 and functions as an oscillation generator. The oscillation membrane 12 may be referred to as a flexible or deformable membrane.

[0023] In the present embodiment, the piezoelectric oscillator 13 is ring-shaped and includes an opening 14. The piezoelectric oscillator 13 is joined with the oscillation membrane 12 so as to close the opening 14. The oscillation membrane 12 may be disk-shaped. The oscillation membrane 12 has a diameter that is larger than that of the opening 14 of the piezoelectric oscillator 13. The diameter of the oscillation membrane 12 may be smaller than that of the piezoelectric oscillator 13.

[0024] For example, the oscillation membrane 12 is adhered to one side (supply plane 13b) of the piezoelectric oscillator 13 so that the center of the oscillation membrane 12 coincides with the center of the piezoelectric oscillator 13. It is preferable that the circumferential edge of the oscillation membrane 12 be entirely adhered to the supply plane 13b. The area of contact between the oscillation membrane 12 and the piezoelectric oscillator 13 is ring-shaped and surrounds the opening 14 of the piezoelectric oscillator 13. The atomization portion 11 of the oscillation membrane 12 is formed in correspondence with the opening 14 of the piezoelectric oscillator 13. The atomization portion 11 is defined by, for example, a circular region. In the illustrated embodiment, the center of the atomization portion 11 coincides with the centers of the oscillation membrane 12 and the piezoelectric oscillator 13.

[0025] Referring to Figs. 3 and 4, the oscillation membrane 12 includes a mist discharge surface 12a and a liquid reception surface 12b. The mist discharge surface 12a is the surface at the side joined with the piezoelectric oscillator 13. Mist is discharged from the mist discharge surface 12a. The liquid reception surface 12b is opposite to the mist discharge surface 12a. Further, the liquid reception surface 12b is supplied with liquid from which mist is generated.

[0026] Referring to Fig. 4, each pore 10 includes openings Dout and Din arranged in the mist discharge surface 12a and the liquid reception surface 12b, respectively. The opening Dout in the mist discharge surface 12a is smaller than the opening Din in the liquid reception surface 12b. In the example of Fig. 4, the inner surface of each pore 10 in the oscillation membrane 12 is an oblique curved surface expressed by an exponential function curve. The inner diameter of the pore 10 gradually increases from the opening Dout in the mist discharge surface 12a to the opening Din in the liquid reception surface 12b. Due to such shape of the pores 10, oscillation of the oscillation membrane 12 atomizes the liquid supplied to the liquid reception surface 12b and discharges the atomized liquid from the mist discharge surface 12a.

[0027] Referring to Figs. 2 and 3, the piezoelectric oscillator 13 of the present embodiment includes a ring-shaped piezoelectric body 15, which has two opposite surfaces 15a and 15b, and thin film electrodes 16a and 16b, which are respectively formed on the two surfaces 15a and 15b of the piezoelectric body 15. Lead wires 17a and 17b are connected to the thin film electrodes 16a and 16b, respectively. A folded portion 18 is formed on the surface 15a of the piezoelectric body 15. The folded portion 18 is continuous with the thin film electrode 16b on the other surface 15b. Further, the folded portion 18 connects the lead wire 17b to the thin film electrode 16b. The piezoelectric oscillator 13 generates oscillation in accordance with input power supplied from the control circuit 4 (refer to Fig. 1) via the lead wires 17a and 17b. The oscillation of the piezoelectric oscillator 13 oscillates the oscillation membrane 12.

[0028] Referring to Fig. 5, voltage is applied to the thin film electrodes 16a and 16b (refer to Fig. 3) to strain the piezoelectric body 15. The strain of the piezoelectric body 15 oscillates the piezoelectric oscillator 13 and repeatedly enlarges and contracts the piezoelectric oscillator 13 in the radial direction (vertical direction as viewed in Fig. 5). Contraction of the piezoelectric oscillator 13 outwardly bulges the liquid reception surface 12b. Enlargement of the piezoelectric oscillator 13 outwardly bulges the mist discharge surface 12a. The continuously repeated bending deformation of the oscillation membrane 12 is referred to as membrane oscillation (so-called ultrasonic oscillation).

[0029] When the oscillation membrane 12 is oscillated, the atomization portion 11 in the mist generator 3 of the present embodiment atomizes the liquid supplied to the pores 10. This generates mist M, which is discharged from the mist discharge surface 12a.

[0030] Referring to Fig. 6, the housing 2 of the cosmetic device 1 includes a nozzle 20, which connects the interior of the housing 2 and the mist discharge port 5. The nozzle 20 includes an inner open end 21, which defines a communication hole 23. A nozzle packing 22, which serves as a sealing member and a holding member, is fixed to the inner open end 21 of the nozzle 20. The discharge plane 13a of the piezoelectric oscillator 13 in the mist generator 3 is in contact with the nozzle packing 22.

[0031] For example, the nozzle packing 22 includes a through hole 24, which corresponds to the communication hole 23 of the nozzle 20. The atomization portion 11 in the mist discharge surface 12a of the oscillation membrane 12 is arranged at a position corresponding to the nozzle 20, in particular, the through hole 24 and the communication hole 23. The nozzle packing 22 includes an annular lip 25, which is adhered to the mist generator 3 at the discharge plane 13a of the piezoelectric oscillator 13. The lip 25 surrounds the periphery of the through hole 24. The nozzle packing 22 couples the nozzle 20 and the mist generator 3, that is, the inner open end 21 and the piezoelectric oscillator 13, in a manner impervious to liquid.

[0032] A tank packing 27 is attached to the supply plane 13b of the piezoelectric oscillator 13. The tank packing 27 includes a cylindrical coupling portion 28 having an opening located at a position corresponding to the liquid reception surface 12b of the oscillation membrane 12. The coupling portion 28 is attached to the tank 29 in a manner impervious to liquid. The tank 29 serves as a liquid supply or a liquid source.

[0033] The liquid reception surface 12b of the oscillation membrane 12 is supplied with liquid L from the tank 29. In the present embodiment, the piezoelectric oscillator 13, the nozzle packing 22, and the tank packing 27 are fastened by a fastening member (not shown) to the housing 2 in a state forced against the inner open end 21 of the nozzle 20. The supply plane 13b of the piezoelectric oscillator 13 and the liquid reception surface 12b of the oscillation membrane 12 are adhered to the tank packing 27. This couples the liquid reception surface 12b and the tank 29 in a manner impervious to liquid.

[0034] Referring to Figs. 2 and 6, in the present embodiment, an electrodeless portion 30, which does not include the thin film electrode 16a, is formed around the opening 14 in the discharge plane 13a of the piezoelectric oscillator 13. The lip 25 of the nozzle packing 22 is in contact with the electrodeless portion 30.

[0035] When liquid L continuously contacts the liquid reception surface 12b of the oscillation membrane 12, the liquid L may permeate through the pores 10 to the mist discharge surface 12a. If the permeated liquid L collects on the thin film electrode 16a on the discharge plane 13a, this may cause short-circuiting, migration, or the like. However, the nozzle packing 22 is in contact with the electrodeless portion 30 of the discharge plane 13a. This prevents the liquid L permeated to the mist discharge surface 12a from collecting on the thin film electrode 16a and improves the reliability of the cosmetic device 1 in the present embodiment.

Liquid Film Elimination Mode

[0036] The mist generator of the present embodiment includes, or is operable in, a liquid film elimination mode, which will now be described.

[0037] Referring to Fig. 7, the permeated liquid L may form a liquid layer or liquid film LF on the mist discharge surface 12a. For example, when the mist generator 3 is not activated for a certain period of time, liquid L that permeates through the pores 10 to the mist discharge surface 12a forms a liquid film LF covering the mist discharge surface 12a. The liquid film LF on the mist discharge surface 12a may destabilize the mist discharge.

[0038] The mist generator of the present embodiment includes, or is operated in, a normal mode and the liquid film elimination mode. The normal mode oscillates the oscillation membrane 12 to discharge mist (refer to Fig. 5). The liquid film elimination mode oscillates the oscillation membrane 12 to eliminate a liquid film LF from the mist discharge surface 12a.

[0039] In the present embodiment, the oscillation energy of the oscillation membrane 12 is increased in the liquid film elimination mode. The oscillation energy of the oscillation membrane 12 is controlled in accordance with the input power supplied to the piezoelectric oscillator 13.

[0040] For example, referring to Fig. 8, the control circuit 4 (refer to Fig. 1) increases the input power W of the piezoelectric oscillator 13 to a value W1, which is greater than a value W0 that is for the normal mode, during a controlled time period from when the mist generator 3 is activated. In the present embodiment, the increase in the input power W increases the oscillation energy of the oscillation membrane 12 and eliminates a liquid film LF from the mist discharge surface 12a.

[0041] The liquid film elimination mode is automatically executed when the mist generator 3 is activated. After executing the liquid film elimination mode, the control circuit 4 gradually decreases the input power W from value W1 for the liquid film elimination mode to value W0 for the normal mode (shift mode). In the normal mode, the control circuit 4 controls the input power W, which is supplied to the piezoelectric oscillator 13, to be constant (W0).

[0042] The operation of the liquid film elimination mode in the present embodiment will now be described.

[0043] The piezoelectric oscillator 13 generates oscillation having an amplitude and/or frequency that is in accordance with the input power W. Accordingly, an increase in the input power W of the piezoelectric oscillator 13 increases the oscillation energy of the oscillation membrane 12. The oscillation energy has a positive correlation (proportional to square) with the oscillation amplitude of the oscillation membrane 12.

[0044] More specifically, when an increase in the oscillation energy oscillates the oscillation membrane 12 with a large amplitude, the liquid film LF is thrust off the mist discharge surface 12a. After elimination of the liquid film LF, the mist generator 3 operates in the normal mode and stably discharges mist.

[0045] The liquid film elimination mode and/or the control circuit 4 that executes the liquid film elimination mode is an example of a liquid film eliminator. The value W0 for the normal mode is one example of a first input power setting value indicating the input power that is suitable for generating the oscillation required to atomize liquid. The value W1 for the liquid film elimination mode is one example of a second input power setting value indicating the input power that is suitable for generating the oscillation required to eliminate a liquid film from the mist discharge surface 12a. The values W0 and W1 are stored in a memory or data storage, which is accessible by the control circuit 4. The memory or data storage may be included in the control circuit 4.

[0046] The present embodiment has the advantages described below.

(1) The mist generator 3 includes the oscillation membrane 12, which is provided with the porous atomization portion 11, and the piezoelectric oscillator 13, which oscillates the oscillation membrane 12 and serves as the oscillation generator. The mist generator 3 includes, or is operable in, the liquid film elimination mode, which oscillates the oscillation membrane 12 to eliminate a liquid film LF from the mist discharge surface 12a.
In the above structure, the liquid film LF can be easily and conveniently eliminated from the mist discharge surface 12a. Thus, there is no need to wipe off the liquid film LF from the mist discharge surface 12a with a cotton swab or the like. Further, after elimination of the liquid film LF, the mist generator 3 executes a control mode (normal mode) for discharging mist as originally intended. This discharges mist in a further stable manner. In particular, the mist discharged from the cosmetic device 1 is often directed toward the user's face. Accordingly, a stable mist discharge would improve the effect of the mist and, for example, prevent makeup from coming off.

(2) The liquid film elimination mode increases the oscillation energy of the oscillation membrane 12. The oscillation energy has a positive correlation with the oscillation amplitude of the oscillation membrane 12. Accordingly, an increase in the oscillation energy oscillates the oscillation membrane 12 with a larger amplitude. This thrusts off the liquid film LF from the mist discharge surface 12a.

(3) The liquid film elimination mode increases the input power W for the piezoelectric oscillator 13. The piezoelectric oscillator 13 generates oscillation that is in accordance with the input power W. Accordingly, the oscillation energy of the oscillation membrane 12 can easily be increased without adding any new components. This thrusts off the liquid film LF from the mist discharge surface 12a.

(4) The liquid film elimination mode is performed when the mist generator 3 is activated.
As the time of contact between the oscillation membrane 12 and liquid becomes longer in a state in which mist is not generated, more liquid is apt to flow out to the mist discharge surface 12a. In particular, with the portable type cosmetic device 1, vibrations produced when carrying the cosmetic device 1 advances the flow of liquid to the mist discharge surface 12a. With the above structure, a liquid film LF is automatically eliminated in a state in which the possibility of a liquid film LF being formed is highest. This improves convenience and further improves convenience of the cosmetic device 1.

(5) After the liquid film elimination mode is completed, a shift mode is performed to gradually decrease the input power W. This allows for smooth shifting to the normal mode without any awkwardness.

Second Embodiment

[0047] A second embodiment of the present invention will now be described. Like or same reference numerals are given to those components that are the same as the corresponding components of the first embodiment. Such components will not be described.

[0048] Referring to Fig. 9, in the present embodiment, the liquid film elimination mode is performed by repeating precipitous increases and decreases of the input power W.

[0049] For example, the control circuit 4 activates the mist generator 3 and precipitously increases the input power W for the piezoelectric oscillator 13 to the peak value W2 and then drops the input power W to the value of "0." In this embodiment, the peak value W2 is greater than the value W0 for the normal mode. The precipitous increasing and decreasing of the input power W is repeated for a predetermined time that corresponds to the liquid film elimination mode. The value W2 is one example of a second input power setting value.

[0050] By repeating the precipitous increasing and decreasing of the input power W in this manner, oscillation having a relatively large amplitude and oscillation having a relatively small amplitude are repeated. Such changes in the amplitude produces an impact that thrusts off a liquid film LF from the mist discharge surface 12a.

[0051] Accordingly, the structure of the present embodiment also eliminates a liquid film LF from the mist discharge surface 12a and allows for mist to be discharge with further stability. This can easily be achieved by controlling the input power without adding any new components like in the first embodiment. Further, this advantage becomes further prominent when increasing the input power W (W2>W0). The values W0 and W2 are stored in a memory or data storage, which is accessible by the control circuit 4. The memory or data storage may be included in the control circuit 4.

Third Embodiment

[0052] A third embodiment of the present invention will now be described. Like or same reference numerals are given to those components that are the same as the corresponding components of the first embodiment. Such components will not be described.

[0053] In the liquid film elimination mode of the present embodiment, the piezoelectric oscillator 13 generates oscillation differently from the radial direction oscillation (Fig. 5) that oscillates the oscillation membrane 12 and atomizes liquid.

[0054] More specifically, in addition to enlargement and contraction oscillation in the radial direction as described above, the ring-shaped piezoelectric oscillator 13 may use differences in the frequency of the oscillation to generate various types of oscillations, such as thicknesswise direction oscillation, flexural oscillation, and torsional oscillation. Further, the piezoelectric oscillator 13 is oscillated by the strain produced in the piezoelectric body 15 when voltage is applied to the thin film electrodes 16a and 16b. Accordingly, oscillation of the piezoelectric oscillator 13 may be controlled in accordance with the timing (e.g., frequency) for supplying input power to the piezoelectric oscillator 13.

[0055] In this regard, the mist generator 3 of the present embodiment generates, with the piezoelectric oscillator 13, oscillation having a frequency differing from the radial direction oscillation that oscillates the oscillation membrane 12. For example, referring to Fig. 10, a liquid film elimination oscillation λ2 (e.g., 4 MHz) is superimposed with an atomizing oscillation λ1 (e.g., 100 KHz), which oscillates the oscillation membrane 12. In the present embodiment, the liquid film elimination oscillation λ2 is a thicknesswise direction oscillation. Two different oscillations are transmitted to the oscillation membrane 12 to eliminate a liquid film LF from the mist discharge surface 12a.

[0056] The structure of the present embodiment also eliminates a liquid film LF from the mist discharge surface 12a and further stabilizes mist discharge. Further, by superimposing the oscillation that eliminates a liquid film LF to the oscillation that atomizes liquid, mist can be discharged even during the liquid film elimination mode. This can easily be achieved by controlling the input power without adding any new components like in the first and second embodiments.

Fourth Embodiment

[0057] A fourth embodiment of the present invention will now be described. Like or same reference numerals are given to those components that are the same as the corresponding components of the first embodiment. Such components will not be described.

[0058] Referring to Fig. 11, the mist generator 3 of the present embodiment includes a vibrator 31 in addition to the oscillation membrane 12 and the piezoelectric oscillator 13. The piezoelectric oscillator 13 and the vibrator 31 form the oscillation generator of the present embodiment. The operation of the vibrator 31 is controlled by the control circuit 4 (refer to Fig. 1) in the same manner as the piezoelectric oscillator 13. The liquid film elimination mode of the present embodiment is performed by applying a low frequency oscillation to the oscillation membrane 12 with the vibrator 31.

[0059] The application of a low frequency oscillation to the oscillation membrane 12 also eliminates a liquid film LF from the mist discharge surface 12a. Accordingly, such a structure would also eliminate a liquid film LF from the mist discharge surface 12a and allow for stable mist discharge.

[0060] It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, it should be understood that the present invention may be embodied in the following forms.

[0061] In the above embodiments, the mist generator 3 is incorporated in the portable type cosmetic device. However, a mist generator according to the present invention may be used in a stationary type cosmetic device or a device other than a cosmetic device.

[0062] In the above embodiments, the mist generator 3 is formed by joining the disk-shaped oscillation membrane 12 with the ring-shaped piezoelectric oscillator 13 so as to cover the opening 14. However, the shapes of the piezoelectric oscillator 13 and oscillation membrane 12 and the shape of the area of contact between these two components are not limited in such a manner. For example, a tubular piezoelectric oscillator and tetragonal oscillation membrane may be used. Further, the piezoelectric oscillator may include a plurality of holes. However, from the viewpoint of efficient oscillation of the oscillation membrane, it is preferable that the piezoelectric oscillator and the oscillation membrane be shaped as described in the above embodiments.

[0063] In the above embodiments, the liquid film elimination mode is performed when the mist generator 3 is activated. However, the liquid film elimination mode is not limited in such a manner and may be performed at times other than when the mist generator 3 is activated. For example, a start switch may be arranged on the housing 2 so that the liquid film elimination mode is performed at any timing. This improves convenience for the user.

[0064] In particular, with the portable type cosmetic device 1, the mist discharge port 5 may be inclined in various directions. This may form a liquid film LF on the oscillation membrane LF during use. By performing the liquid film elimination mode in such a case, convenience is significantly improved. This would allow for mist treatment to always be stably performed and improves convenience.

[0065] In the first embodiment, the oscillation energy is increased by increasing the input power W of the piezoelectric oscillator 13. Instead, for example, a structure such as the vibrator 31 of the third embodiment may be added to increase the oscillation energy.

[0066] In the second embodiment, precipitous increases of the input power W for the piezoelectric oscillator 13d to the peak value W2 and decreases of the input power W to the value of "0" are repeated. Instead, referring to Fig. 12, precipitous increases of the input power W to a peak value W3 and decreases of the input power W to a value W4, which is lower than the peak value W3, may be repeated. In this example, the value W4 is higher than the value W0 for the normal mode. However, the value W4 may be set to be lower than the value W0. This narrows the increasing and decreasing width of the input power W, reduces the load on the piezoelectric oscillator 13, and increases reliability. The set of the values W3 and W4 is one example of a second input power setting value.

[0067] In the second embodiment, in addition to the precipitous increase and decrease of the input power W, the input power W is increased (W2>W0). Instead, referring to Fig. 13, the peak value of the increase and decrease of the input power W may be reduced to the value W0 so that the input power W does not increase from the value W0. Such a structure would also obtain a liquid film elimination effect that uses impacts produced by such changes in the oscillation.

[0068] In the third embodiment, the piezoelectric oscillator 13 generates a thicknesswise direction oscillation (A2) as an oscillation that differs from the radial direction oscillation, which oscillates the oscillation membrane 12 and atomizes liquid. Instead, the oscillation generated in the liquid film elimination mode may be flexural oscillation, torsional oscillation, or other types of oscillation.

[0069] In the third embodiment, the liquid film elimination oscillation A2 (4 MHz) has a higher frequency than the atomizing oscillation A1 (100 KHz), which oscillates the oscillation membrane 12. Instead, a liquid film elimination oscillation may have a lower frequency than the atomizing oscillation λ1.

[0070] In the third embodiment, the liquid film elimination oscillation λ2 is superimposed with the atomizing oscillation λ1. Instead, only the liquid film elimination oscillation λ2 may be generated in the piezoelectric oscillator 13 during the liquid film elimination mode. Further, after the liquid film elimination mode is performed, the atomizing oscillation λ1 may be generated as the normal mode.

[0071] In the liquid film elimination mode, two or more of the increase in the oscillation energy, the increase in the input power, the precipitous increase and decrease of the input power W, and the application of a different oscillation may be performed in combination.

[0072] The present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.

Claims

1. A mist generator (3) including:

an oscillation membrane (12) including a porous atomization portion (11);

a liquid supply (29) for supplying liquid (L) to the atomization portion (11); and

an oscillation generator (13; 31) for oscillating the oscillation membrane (12) and atomizing the liquid (L) supplied to the atomization portion (11); the mist generator being characterized by a liquid film elimination mode for eliminating a liquid film (LF) from a mist discharge surface (12a) of the oscillation membrane (12) by oscillating the oscillation membrane.

2. The mist generator according to claim 1, wherein the liquid film elimination mode oscillates the oscillation membrane (12) with increased oscillation energy.

3. The mist generator according to any one of the preceding claims, wherein
the oscillation generator (13; 31) includes a piezoelectric oscillator that generates oscillation having an amplitude and/or frequency that is in accordance with the level of input power, and
the liquid film elimination mode increases the input power supplied to the piezoelectric oscillator.

4. The mist generator according to any one of the preceding claims, wherein
the oscillation generator (13; 31) includes a piezoelectric oscillator that generates oscillation having an amplitude and/or frequency that is in accordance with the level of input power, and
the liquid film elimination mode repeats precipitous increase and decrease of the input power supplied to the piezoelectric oscillator.

5. The mist generator according to any one of the preceding claims, wherein the liquid film elimination mode oscillates the oscillation membrane (12) in a manner that differs from when the liquid is atomized.

6. The mist generator according to any one of the preceding claims, wherein the liquid film elimination mode oscillates the oscillation membrane (12) with a frequency that differs from that when the liquid is atomized.

7. The mist generator according to any one of the preceding claims, wherein the liquid film elimination mode oscillates the oscillation membrane (12) with a relatively low frequency.

8. The mist generator according to any one of the preceding claims, wherein the liquid film elimination mode generates oscillation having a waveform obtained by superimposing oscillation that eliminates the liquid film (LF) on oscillation that atomizes the liquid.

9. The mist generator according to any one of the preceding claims, wherein the liquid film elimination mode is executed when the mist generator is activated.

10. A cosmetic device comprising the mist generator according to any one of the preceding claims.

11. A control circuit for controlling a mist generator that oscillates an oscillation membrane (12) and atomizes liquid supplied to a liquid reception surface of the oscillation membrane (12) and discharges the atomized liquid from a mist discharge surface (12a) of the oscillation membrane (12), the control circuit comprising:

a memory for storing a first input power setting value, which indicates first input power that generates oscillation suitable for atomizing the liquid, and a second input power setting value, which indicates second input power that generates oscillation suitable for eliminating a liquid film (LF) from the mist discharge surface (12a);

a normal mode for oscillating the oscillation membrane (12) in accordance with the first input power setting value; and

a liquid film elimination mode that oscillates the oscillation membrane (12) in accordance with the second input setting value;

wherein the control circuit

executes the liquid film elimination mode to eliminate the liquid film (LF) during a controlled time period immediately after the mist generator is activated, and

executes the normal mode to discharge mist by controlling the input power in accordance with the first input power setting value after executing the liquid film elimination mode.

Drawing