Nebulizer

Abstract

A nebulizer comprises a head detachably coupled to a body. The head comprises a nebulizer, an air channel and a flow sensor. A nebulized liquid is released in an air channel that ends in a mouth piece through which a user inhales and exhales. The inhaling and exhaling causes a flow in the air channel which is detected with the flow sensor. The nebulizer is controlled by a controller included in the body.

Claims

1. A nebulizer assembly comprising: a head comprising: a medication chamber configured to hold a liquid; a vibration source configured to nebulize the liquid, the vibration source comprising a mesh; an air channel in which the nebulized liquid is released, the air channel being arranged to guide a flow caused by an inhaled and exhaled breath of a user, wherein the flow is guided along the mesh, and wherein the air channel has a first side and a second side opposite the first side, wherein the air channel ends at the first side in a mouthpiece configured to deliver the nebulized liquid to the user, and wherein the second side is in communication with ambient air; and a sensor configured to generate output signals that convey information related to the flow; and a body detachably coupled to the head, the body comprising a controller configured to control the vibration source, the controller including driving circuitry for controlling the vibration source, wherein, the sensor is a thermal flow sensor comprising an electrically driven thermal element configured to sense flow in the air channel.

2. The nebulizer assembly according to claim 1, wherein the controller is configured to energize the vibration source based on a signal received from the sensor.

3. The nebulizer assembly according to claim 2, wherein the signal corresponds to a direction of the flow in the air channel.

4. The nebulizer assembly according to claim 1, further comprising: a pressure sensor arranged to sense the flow based on a pressure measurement.

5. The nebulizer assembly according to claim 4, wherein the thermal flow sensor comprises an electrically driven thermal element disposed on a front side of the thermal flow sensor device, the front side facing the interior of the air channel.

6. The nebulizer assembly according to claim 1, wherein the thermal flow sensor comprises an integrated circuit die that includes an electrically driven thermal element disposed on the front side and one or more bondpads at a backside of the thermal flow sensor opposite the front side, the one or more bondpads being electrically coupled to the thermal element.

7. The nebulizer assembly according to claim 1, wherein the thermal element comprises a heating element and at least two temperature sensing elements.

8. The nebulizer assembly according to claim 1, wherein the air channel comprises a wall having a recess defined therein in which the thermal flow sensor is mounted with the electrically driven thermal element facing the air channel.

9. The nebulizer assembly according to claim 1, wherein the mesh is detachably coupled to the medication chamber.

10. The nebulizer assembly according to claim 1, wherein the medication chamber is formed such that the mesh is separated from the vibration source by a gap, the vibration source being configured to vibrate at a frequency f, the mesh being separated from the vibration source by the gap forming a distance between the mesh and the vibration source of substantially Lambda/2, wherein Lambda=v/f, v being the speed of a wave in the liquid caused by the vibration at frequency f.

11. The nebulizer assembly according to claim 1, further comprising an electrical energy source arranged to transfer energy from the body to the head to energize the vibration source, the flow sensor, or both using a magnetic field coupling between the head and the body.

12. The nebulizer assembly according to claim 1, wherein the signal from the sensor is transferred from the head to the body using a magnetic field, an optical coupling, or both.

13. A method of detecting an inhaled or exhaled breath of a person using a nebulizer, the method comprising the step of: generating vibrational energy with a vibration source disposed within a head of the nebulizer to nebulize a liquid, wherein the vibrational energy is provided to the liquid while the liquid is held in a medication chamber, the medication chamber being within the head of the nebulizer; generating with a sensor disposed within the head of the nebulizer, output signals that convey information related to a flow in the air channel of the nebulizer, the flow being caused by an inhaled or exhaled breath of a user, the air channel being configured to guide the flow along a mesh in the vibration source, and wherein the air channel has a first side and a second side opposite the first side, wherein the air channel ends at the first side in a mouthpiece configured to deliver the nebulized liquid to the user, and wherein the second side is in communication with ambient air, controlling with a controller the vibration source, the controller being disposed in a body of the nebulizer that is detachably coupled to the head, wherein the controlling includes driving a circuit to control vibration of the vibration source, and wherein the sensor is a thermal flow sensor comprising an electrically driven thermal element configured to sense flow in the air channel.

14. A nebulizer assembly comprising: a head comprising: a medication chamber configured to hold a liquid; a vibration source configured to nebulize the liquid, the vibration source comprising a mesh; an air channel in which the nebulized liquid is released, the air channel being arranged to guide a flow caused by an inhaled and exhaled breath of a user, wherein the flow is guided along the mesh; and a sensor configured to generate output signals that convey information related to the flow; and a body detachably coupled to the head using a magnetic field coupling, wherein: the magnetic field coupling comprises two U shaped cores, the U shapes cores having legs configured to align when the body is detachably coupled to the head; the body comprises a controller configured to control the vibration source, the controller including driving circuitry for controlling the vibration source; and the sensor is a thermal flow sensor comprising an electrically driven thermal element configured to sense flow in the air channel.

15. The nebulizer assembly according to claim 14, wherein the controller is configured to energize the vibration source based on a signal received from the sensor.

16. The nebulizer assembly according to claim 15, wherein the signal corresponds to a direction of the flow in the air channel.

17. The nebulizer assembly according to claim 14, further comprising: a pressure sensor arranged to sense the flow based on a pressure measurement.

18. The nebulizer assembly according to claim 17, wherein the thermal flow sensor comprises an electrically driven thermal element disposed on a front side of the thermal flow sensor device, the front side facing the interior of the air channel.

19. The nebulizer assembly according to claim 14, wherein the thermal flow sensor comprises an integrated circuit die that includes an electrically driven thermal element disposed on the front side and one or more bondpads at a backside of the thermal flow sensor opposite the front side, the one or more bondpads being electrically coupled to the thermal element.

20. The nebulizer assembly according to claim 14, wherein the thermal element comprises a heating element and at least two temperature sensing elements.

21. The nebulizer assembly according to claim 14, wherein the air channel comprises a wall having a recess defined therein in which the thermal flow sensor is mounted with the electrically driven thermal element facing the air channel.

22. The nebulizer assembly according to claim 14, wherein the mesh is detachably coupled to the medication chamber.

23. The nebulizer assembly according to claim 14, wherein the medication chamber is formed such that the mesh is separated from the vibration source by a gap, the vibration source being configured to vibrate at a frequency f, the mesh being separated from the vibration source by the gap forming a distance between the mesh and the vibration source of substantially Lambda/2, wherein Lambda=v/f, v being the speed of a wave in the liquid caused by the vibration at frequency f.

24. The nebulizer assembly according to claim 14, further comprising an electrical energy source arranged to transfer energy from the body to the head to energize the vibration source, the flow sensor, or both using the magnetic field coupling between the head and the body.

25. The nebulizer assembly according to claim 14, wherein the signal from the sensor is transferred from the head to the body using the magnetic field, an optical coupling, or both.

26. A method of detecting an inhaled or exhaled breath of a person using a nebulizer, the method comprising the step of: generating vibrational energy with a vibration source disposed within a head of the nebulizer to nebulize a liquid, wherein the vibrational energy is provided to the liquid while the liquid is held in a medication chamber, the medication chamber being within the head of the nebulizer; generating with a sensor disposed within the head of the nebulizer, output signals that convey information related to a flow in an air channel of the nebulizer, the flow being caused by an inhaled or exhaled breath of a user, the air channel being configured to guide the flow along a mesh in the vibration source, controlling with a controller the vibration source, the controller being disposed in a body of the nebulizer that is detachably coupled to the head using a magnetic field coupling, wherein the magnetic field coupling comprises two U shaped cores, the U shapes cores having legs configured to align when the body is detachably coupled to the head, wherein the controlling includes driving a circuit to control vibration of the vibration source, and wherein the sensor is a thermal flow sensor comprising an electrically driven thermal element configured to sense flow in the air channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) How the present invention may be put into effect will now be described by way of example with reference to the appended drawings, in which:

(2) FIG. 1 shows an embodiment of a nebulizer according to the invention;

(3) FIG. 2 shows an embodiment of an air channel;

(4) FIG. 3 shows an embodiment of an integrated circuit;

(5) FIG. 4 shows an air channel with a thermal flow sensor; and

(6) FIG. 5 shows a further embodiment of a nebulizer.

(7) The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(8) The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims.

(9) FIG. 1 shows a nebulizer 10 comprising a head 20 and a body 30 wherein the head is detachable from the body to facilitate for example steam cleaning of the head after use. The body comprising controlling means 60, 62 may be rinsed to clean it. Steam cleaning is not necessary as the body has no direct contact with a medication liquid or inhaled 5 or exhaled 7 breath. This is advantageous for the expected lifetime of the body as the steam can have a detrimental effect on electronic circuits such as the controlling means that are included in the body. The head comprises a medication chamber 40, a vibration source 44 such as a piezo electric element, a mesh 42 and an air channel 50. The vibration source is activated by the driving circuit 60 to cause a standing wave in the liquid. The liquid may for example comprise a medication dissolved in water and is also referred to as medication liquid. The standing wave between the vibration source and the mesh causes the ejection of droplets in the air channel. The air channel ends at one side in a mouthpiece 70 and at the other side in an ambient port 51 which is in open contact with ambient air. A user puts the mouthpiece 70 against his mouth and inhales 5 and exhales 7 causing a flow through the air channel. The inhaling and exhaling is detected by the sensing means 52 and an output of the sensing is coupled to the controlling means 60, 62. A signal 54 indicative of the inhaling and exhaling is used by the controlling means to synchronize the driving circuit 60 with the breathing such that for example during exhaling the nebulizing of the medication liquid is interrupted. To allow cleaning the head can be opened, for example along line 43, to allow access to the interior of the air channel as well as to the mesh 42. The mesh is detachable from the medication chamber such that also the interior of the medication chamber may be cleaned. A further advantage of a detachably coupled mesh is that it can be replaced when its performance has worsened for example because a predetermined percentage of the plurality of holes in the mesh has become obstructed.

(10) When the head is coupled to the body an electrical connection between the driving circuit 60 and the vibration source 44 and between the flow sensor 52 and a processor 62 is obtained. The processor determines the driving frequency and duty cycle of a driving signal 45 which is provided by the driving circuit 60 to the vibration source 44. The electrical coupling may be realized with a plug-socket type of connection. For durability and reliability it may be advantageous to have a magnetic field coupling which is discussed later. The processor 62 and the sensing means 52 may further have an optical coupling which does not suffer from a possible interference caused by the magnetic field.

(11) In FIG. 1 the nebulizing means may comprise a cylindrical shaped medication chamber 40 having a detachably coupled mesh at one side and a piezo electric element glued to it at the other side. The volume of the medication chamber is preferably small to prevent that a relative large amount of left medicine needs to be removed when cleaning the head. The volume can be minimized by reducing the distance or gap between the mesh and the piezo electric element. However to obtain a standing wave between the piezo electric element and the mesh the distance should not be smaller than approximately /2 [m], wherein is the wavelength. The wavelength is dependent on the frequency of the vibration and the propagation speed in the medicine. For efficient operation and a medication chamber with a small volume the distance between the mesh and the piezo electric element is approximately /2 [m], [m] or 3 /2 [m]. In a further embodiment of the nebulizing means the mesh 42 has a concave shape to obtain an improved dispersion of the cloud of droplets in the air channel.

(12) In the invention the flow caused by an inhaling or exhaling user is detected by sensing means 52 which are included in the head 20 of the nebulizer. In a further embodiment the sensing means 52 are positioned to detect the flow in a portion of the air channel 50 between the medication chamber 40 and the ambient port 51 which has a smaller cross section than a further portion of the air channel between the medication chamber and the mouthpiece 70. By measuring the flow in the narrower portion of the air channel the signal 54 from the sensing means provides a better representation of the actual flow in the air channel. Further the value of the flow will be higher in the narrower portion thereby enhancing the sensitivity of the flow measurement.

(13) The sensing means 52 may for example comprise a pressure sensor that measures the pressure in the air channel 50. The pressure changes during inhaling 5 or exhaling 7 of the user and therefore the pressure sensor enables the detection of the flow in the air channel.

(14) In a further embodiment the sensing means may comprise a flow sensor. The flow sensor may for example comprise a valve that moves as a result of the flow in the air channel. The movement of the valve may be used to distinguish between an inhaling and exhaling breath.

(15) In a further embodiment the flow sensor comprises a thermal element and senses the flow caused by the inhaled and exhaled breath based on a temperature measurement. Such a flow sensor is referred to as a thermal flow sensor device and has the advantage of not comprising any moving parts.

(16) FIG. 1 further shows a nebulizing system comprising the nebulizer 10 and a personal computer (PC) 92. The nebulizer comprises communication means 90 which enable a data exchange with the personal computer 92. In an embodiment of the system the user may couple the nebulizer with a USB cable 91 to his PC. The coupling may however also be wireless. A program on the PC may be used to train the person in the use of the nebulizer. For example the user may need to be trained in inhaling and exhaling having the nebulizer pressed against his mouth. In the training method the person is asked to inhale and exhale through air channel 50 of the nebulizer. The instruction for inhaling 5 and/or exhaling 7 may be shown on the screen of the PC. The sensing means 52 measure the flow caused by the inhaling and exhaling of the person and data corresponding to the measured flow is transmitted with the communication means 90 to the PC. In response to the received data feedback is given to the person. This feedback may comprise further instructions such as for example to breathe slower or deeper.

(17) In a further embodiment the training method is implemented in the processor 62 of the nebulizer 10. The instructions to the person may be given audible. Feedback may also be given audible, for example in terms of a sound indicating a pass when the inhaling and exhaling complied with predetermined criteria or a fail when during the training the breathing did not comply with the predetermined criteria. In a further embodiment feedback is given visually for example on a LCD screen on the nebulizer body 30. The LCD screen may display for example further instructions to breathe slower or deeper.

(18) FIG. 2 shows a portion of the air channel 50. The inhaled 5 and exhaled 7 breath cause a flow through the air channel which is detected with a thermal flow sensor device 53. The thermal flow sensor device may for example be positioned in a recess in the wall 58. After use the air channel may be cleaned by opening the head as discussed earlier. To prevent any residue the surface of the flow sensor device preferably matches with the wall 58 surrounding it to obtain a smooth interior in the air channel. The thermal element on the flow sensor device may comprise a thermal heating element 56a and two thermal sensor elements 56b surrounding it. In case there is no flow the two thermal sensor elements 56b will both measure approximately the same temperature. In case the left thermal sensor element measures a higher temperature than the right thermal sensor element the flow must be from right to left as the flow transports the heat produced by the thermal heating element 56a causing a small rise in temperature of the left thermal sensing element. Hence the detected flow was caused by an inhaling breath 5 of the user. Likewise the exhaling is detected by the thermal flow sensor device.

(19) In a further embodiment the flow sensor detects not only the direction of the flow in the air channel but also its rate. When a detected rate is above or below a predetermined threshold the controlling means may give a warning to the user. In a further embodiment the nebulizer may be put in a training mode in which no atomization of the medicine takes place and the user is instructed to inhale and exhale whereby the controlling means give a warning when the inhaling or exhaling is causing a too large or too small flow for the nebulizer to work effectively.

(20) FIG. 3 shows a cross section of a portion of a processed integrated circuit 130 that is part of the thermal flow sensor device 53. Facing upwards is the component side comprising a polysilicon (PS) resistor 300 that is connected with a metal track 600. On top of the polysilicon resistor other layers may be formed such as a further metal layer 750 which can be used to tune thermal conductivity. The metal track 600 contacts the substrate 200 through a contact hole (CO) and after the back side etching of the substrate the backside (the side facing downward) of the metal track is accessible and forms a bonding area or bondpad at the backside of the die. With the shown bonding 160 at the bondpad a connection with one of the two terminals of the PS resistor is realized.

(21) Before the etching of the substrate takes place the die is connected via a glue layer 1000 to an electrical insulating substrate such as glass layer 900. The thin layer (typically 400 micrometer) of glass provides a good thermal conductivity to the PS resistor. Further the glass layer provides mechanical stability to the die to enable the etching through the substrate to the metal track.

(22) The integrated circuit 130 further comprises thermal sensing elements surrounding the heating element. A temperature difference between any two thermal sensing elements may be used to determine the flow direction in the air channel. The thermal sensing element may for example comprise a PN junction of which the forward voltage is dependent on temperature. In a further embodiment the thermal sensing element comprises a string of thermocouples, each thermocouple comprising a polysilicon-metal junction. This provides the advantage that no additional layers and processing is required to obtain the thermal sensing element as it is made in the same process steps as the polysilicon resistor 300 and the metal track 600 and can be connected from the backside in the same way as the PS resistor as discussed earlier.

(23) In a further embodiment the thermal flow sensor device 52 in the air channel 50 is calibrated using a predetermined flow with a known direction and rate. The detected temperature differences sensed by the thermal sensing elements are stored in a look up table. The look up table may for example be stored in a memory comprised in the controlling means 60, 62. In use the temperature differences sensed by the thermal flow sensor device 53 are compared with stored values from the look up table to determine the flow rate in the air channel.

(24) The above discussed calibration method is also applicable for other sensing means such as a pressure sensor.

(25) FIG. 4 shows a further cross section of a portion of a processed integrated circuit 130 with a different implementation of the back side contacting. As in FIG. 3 the thermal heating element is realized with a PS resistor 300 that is connected to a metal track 600. The substrate 200 in this implementation is however highly doped and therefore low resistive. As discussed earlier the wafer (containing a plurality of the dies) is bonded (using glue 1000) to a glass layer 900. The backside of the wafer obtains a metal layer 210 on the substrate and is subsequently etched resulting in electrically isolated pillars 240 to remain. Shown is a pillar 240 that connects via the metal track 600 to a terminal of the PS resistor 300. The metal on the pillars forms bondpads and can be contacted with wire bonding or can be connected to pads on a printed circuit board (PCB) 290 using stud bumps. An adhesive 330 is applied between the PCB and the integrated circuit 130 to prevent penetration of dirt or vapor. The thermal flow sensor device comprises the assembly of the integrated circuit 130 and the PCB 290. The assembly is mounted in a window in the wall 58 of the air channel and sealed to prevent leakage. The glass layer 900 faces the interior of the air channel. In a further embodiment the wall 58 has a locally thinned part in which the assembly is fitted such that the thinned part separates the integrated circuit die from the interior of the air channel. The thinned part provides an improved barrier to reduce a risk of leakage or contamination.

(26) FIG. 5 shows a further embodiment of the nebulizer in which only those parts relevant for the discussion are shown. In this embodiment the driver circuit 60 activates the vibration source 44 using a magnetic field coupling between the body 30 and the head 20. This provides the advantage that no electrical contacts are accessible at the exterior of the head and the body. Electrical contacts at the exterior may damage due to frequent decoupling of the head and the body or by frequent steam cleaning of the head. The magnetic field coupling comprises two U shaped cores 74, 75 of which the legs are aligned when the head is detachably coupled to the body. When aligned the two U shaped cores make up a split transformer having a primary winding 72 coupled to the driving circuit 60 and a secondary winding 73 coupled to the vibration source 44, which for example is a piezo electric element. The winding ratio of the secondary and primary winding can be used to obtain a predetermined driving voltage for the piezo electric element. The frequency of a current provided by the driving circuit 60 and passing through the primary winding 72 determines the vibration frequency and hence can be used to control the nebulizing of the liquid in the medication chamber. To obtain small dimensions for the split transformer the driving circuit should provide a relative high frequent (e.g., above 1 MHz) AC drive current through the primary winding 72. Having the secondary winding 73 driving the vibration source 44 said relative high frequency may further be used to provide the additional advantage of a relative narrow minimal gap of /2 [m], [m] or 3 /2 [m] between the vibration source 44 and the mesh 42 resulting in the medication chamber having a relative small volume.

(27) In a further embodiment the sensing means included in the nebulizers' head 20 is implemented as a thermal flow sensor device 52 or MEMS pressure sensor mounted in a recess of the air channel. The supply for the sensing means is also obtained with a magnetic field coupling between the head and the body. The split transformer comprises an additional secondary winding for powering the sensing means.

(28) In a further embodiment the split transformer comprises two E shaped cores. The split transformer may have an additional primary winding coupled with a magnetic field coupling to the additional secondary winding. The additional primary and secondary windings for providing energy to the sensing means are each made across the center leg of its corresponding E shaped core whereas the primary and secondary winding for the piezo drive are arranged on the outer legs of the E shaped core. This arrangement provides a separation between the primary winding and the additional primary winding, and between the secondary and additional secondary winding resulting in a reduced interference.

(29) Where the term comprising is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun e.g., a or an, the, this includes a plural of that noun unless something else is specifically stated.

(30) The term comprising, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. Thus, the scope of the expression a device comprising means A and B should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

(31) Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

(32) Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.