Personal Care Devices

Abstract

Schemes, solutions, concepts, designs, methods and systems are proposed that support and / or improve a vibrating personal care device having a cleaning element that vibrates during use. Embodiments are proposed that control the vibration of the cleaning element based on a load force applied to the cleaning element during use. That is, the vibration of the personal care device is adapted based on the pressure applied to the cleaning element (by engagement with a user's tissue surface).

Description

[Technical field]

[0001] The present invention relates to the field of personal care devices, and in particular to the field of personal care devices having cleaning elements that vibrate during use. [Background technology]

[0002] Personal care devices, such as electric brushes and shaving devices, are used regularly (eg, daily). Summary of the Invention [Problem to be solved by the invention]

[0003] Such personal care devices typically have cleaning elements (bristles, tufts, elongated projections, etc.) that vibrate during use. The stiffness of the cleaning element may be affected by whether it is vibrating or not, i.e., the stiffness of the cleaning element varies depending on the operating state of the personal care device. However, excessive pressure on the user's tissue surface during use can cause tissue damage.

[0004] Personal care devices are known that have the ability to warn a user when too much pressure is being applied to a tissue surface during use, however, such devices do not include functionality to directly counteract the excessive pressure.

[0005] Also, based on research, achieving the correct stiffness of the cleaning elements and their positioning in the brush of a vibrating personal care device is expected to impact long-term results. For example, mouthpiece-style dental brushes (such as "U-shaped" and "Y-shaped" brushes) have been identified as having problems due in part to poor alignment of the cleaning elements (e.g., bristles) with the user's teeth. [Means for solving the problem]

[0006] The invention is defined by the claims.

[0007] According to an embodiment of an aspect of the present invention there is provided a personal care device comprising: a plurality of cleaning elements for engagement with a surface of a user; a vibration means for vibrating the cleaning element at a range of different vibration frequencies; a pressure sensor that senses a load force applied to at least a first subset of the cleaning elements by a user's engagement with the surface; and a control unit configured to: determine a target frequency based on the sensed load force applied to at least a first subset of the cleaning elements and cleaning element data describing one or more physical characteristics of the cleaning elements, the target frequency affecting at least one of a mechanical response of the cleaning elements or a direction of movement of the cleaning elements; and control the vibration means based on the target frequency.

[0008] The proposed concepts therefore aim to provide schemes, solutions, concepts, designs, methods and systems relating to assisting and / or improving vibrating personal care devices having cleaning elements that vibrate during use.

[0009] In particular, it is proposed to control the vibration of the cleaning element based on the loading force applied to the cleaning element during use. That is to say, the vibration of the personal care device is adapted based on the pressure applied to the cleaning element (by the user's engagement with the tissue surface). In particular, the frequency of the vibration means is set based on the direction and / or the magnitude of the loading force applied to the cleaning element. In this way, the vibrating personal care device actuates the bristles to create a controlled force variation and / or distribution by taking into account the pressure applied by the user. Such variation and / or distribution is non-uniform over the cleaning element of the device.

[0010] The embodiments are based on the realization that the concept of vibrationally exciting bristles or bristles-like structures to create movement across a surface (as used in small robots known as "hair robots") can be utilized to provide improved cleaning in the field of vibratory personal care devices. In particular, small robots are known that can achieve full 360° steering by arranging bristles of different sizes and natural frequencies around the robot body and exciting them with an appropriate mix of vibration frequencies. This effect essentially relies on an asymmetry in the mechanical properties of the bristles, which in turn results in an asymmetry in the response of different bristles to different drive frequencies. By matching the drive frequency / frequency to the known asymmetry, for example, a bristle-based robot can steer at any angle. Other examples of vibrationally controlled mechanical structures have been shown, including 3D printed hairs that can generate movement in controlled directions or dramatically change stiffness given the appropriate input vibration. It is proposed to utilize such concepts to control the vibration of a personal care device to achieve desired characteristics and / or movements of the cleaning elements during use.

[0011] As an example of the proposed concept, a vibrating toothbrush or mouthpiece can measure the magnitude of force applied to its cleaning elements (e.g. bristles) and / or their direction. This occurs when a user presses the device against their teeth and is measured, for example, via a pressure sensor. The sensed magnitude and / or direction can be used together with known properties of the cleaning elements to calculate a target frequency (or frequency mix) that is expected to lead to a desired mechanical response of the cleaning elements and / or a preferred direction of movement of the entire cleaning elements in a particular area of ​​the device. Furthermore, such a desired stiffness and direction of movement can be calculated based on the location of the device in the user's mouth and / or the user's known dental anatomy. As a result, the drive frequency of the vibration means can be adjusted accordingly.

[0012] In other words, the embodiments propose to adapt the vibration of a vibrating personal care device based on the pressure applied to the cleaning elements of the device. Such adaptation results in a specific mechanical response of the cleaning elements and / or a preferred direction of movement of the cleaning elements. Thus, the embodiments can improve cleaning and / or reduce undesired tissue damage during use.

[0013] The embodiments may aid in dental treatment recommendations, for example, by enabling improved cleaning of a user's teeth, gums, tongue, etc. For example, the proposed embodiments aid in improved dental care. Thus, the embodiments may be used in connection with dental care to support dental care professionals when providing treatment to subjects.

[0014] By being integrated into a user's regular brushing regimen, embodiments can support improved dental care. Thus, improved vibration-based dental cleaning can be provided by the proposed concept.

[0015] By controlling the vibration frequency of the cleaning element based on the pressure applied to the cleaning element, it is possible to control the mechanical properties and / or direction of movement of the cleaning element to provide improved cleaning and / or reduced tissue damage, etc.

[0016] Thus, embodiments can provide the advantage of improved tissue cleaning through the use of load-force based control of the vibrating personal care device.

[0017] Some embodiments further include a position sensor for sensing the positioning of at least a subset of the plurality of cleaning elements. In this case, the control unit determines the target frequency further based on the sensed position of at least a first subset of the cleaning elements. For example, the control unit determines a target direction based on the sensed position of at least a first subset of the cleaning elements, and determines the target frequency based on the determined target direction. Thus, for example, the position sensing concept can be used to determine the target frequency to achieve a desired movement direction. Thus, the target frequency of the personal care device can be accurately identified using simple movement and / or position sensing techniques and / or devices.

[0018] In some exemplary embodiments, the control unit further identifies, in use, a surface of a user engaged by the plurality of cleaning elements based on the sensed positions of at least a first subset of the cleaning elements, and determines a target frequency further based on the identified surface of the user.

[0019] By applying spatially resolved forces, embodiments compensate for small deviations in a user's technique (e.g., softening cleaning elements in areas placed over sensitive tissue (such as gums) but not over resilient areas (such as teeth)). Embodiments can also compensate for misalignment of commonly placed cleaning elements with a user's specific anatomy. As a further example, embodiments help users clean complex areas (e.g., around orthodontic appliances) by, for example, creating a "floating" motion from orthodontic appliances by simulating a subset of the cleaning elements provided by the device.

[0020] Other advanced functions such as localized deposition of cleaning paste and localized sampling of bacteria from the user's tissue may be facilitated by such embodiments.

[0021] The control unit may include a communication interface to obtain cleaning element data of the cleaning elements, in this way the control of the vibration frequency can be precisely determined depending on the specific characteristics of the cleaning element, i.e. the control of the vibrating personal care device is tailored to its specific characteristics and thus the cleaning operation is improved or optimized.

[0022] By way of example, the communications interface may retrieve cleaning element data from a database of cleaning element data, such a database may be implemented at least in part in a remotely accessible data storage unit.

[0023] The one or more physical characteristics of the cleaning element may include at least one of the following: shape, type, size, cross-sectional area, arrangement, material, stiffness, length, number of bristles per unit area, and mounting angle. Thus, various mechanical characteristics of the cleaning element can be taken into account when determining the target vibration frequency. Thus, precise and optimal control of the vibration of the cleaning element is enabled by the proposed embodiment.

[0024] In some embodiments, the control unit further determines a second target frequency based on the sensed load force applied to at least the first subset of the cleaning elements and controls the vibration means based on the second target frequency. Thus, embodiments vibrate the cleaning elements at a mix of different frequencies to achieve a desired mechanical response of the cleaning elements and / or a preferred direction of movement of the cleaning elements.

[0025] In an exemplary embodiment, the pressure sensor further senses a load force applied to a second, different subset of the cleaning elements by a user's engagement with the surface. In this case, the control unit further determines a third target frequency based on the sensed load force applied to the second subset of the cleaning elements and controls the vibration means based on the third target frequency. In this manner, different groups or subsets of the cleaning elements can be vibrated at respective frequencies to achieve a desired mechanical response and / or one or more preferred directions of movement.

[0026] The sensed load force may, for example, include at least one of a magnitude value and a direction value, in which case the control unit may determine the target frequency based on at least one of the magnitude value and the direction value.

[0027] At least a first subset of the plurality of cleaning elements includes a vibration-enhancing structure configured to have a predetermined mechanical property in response to being vibrated at a predetermined excitation frequency, for example, the vibration-enhancing structure includes at least one of elongated bristles having different cross-sectional shapes and / or sizes at at least two different locations along the longitudinal length of the bristles, elongated structures attached to the personal care device with an angular bias, and elongated bristles formed of different materials at at least two different locations along the longitudinal length of the bristles.

[0028] The personal care device includes a toothbrush, and preferably includes an oral care device (such as an electric toothbrush) that vibrates when used. In other embodiments, the personal care device includes a mouthpiece, a shaver, or a skin cleansing device that vibrates when used. Thus, one or more of the proposed concepts can be adopted in a variety of personal care devices. Thus, the embodiments have a wide range of applications in the field of personal care devices.

[0029] According to another aspect of the invention there is provided a method of controlling a personal care device comprising a plurality of cleaning elements for engagement with a surface of a user, vibration means for vibrating the cleaning elements at different frequency ranges, and a pressure sensor. The method comprises: sensing, with a pressure sensor, a load force applied to at least a first subset of the cleaning elements by a user's engagement with the surface; determining a target frequency based on the sensed load force applied to at least a first subset of the cleaning elements and cleaning element data describing one or more physical characteristics of the cleaning elements, the target frequency affecting at least one of a mechanical response of the cleaning elements or a direction of movement of the cleaning elements; and controlling the vibration means based on the target frequency.

[0030] According to yet another aspect of the invention there is provided a computer program comprising computer program code means for performing a method according to the proposed embodiments when said computer program is run on a computer.

[0031] There is therefore also provided a computer system including a computer program product according to the proposed embodiments and one or more processors which, upon execution of computer readable program code of the computer program product, perform methods according to the proposed concepts.

[0032] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. [Brief description of the drawings]

[0033] For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which:

[0034] [Figure 1] FIG. 1 shows a simplified schematic block diagram of an electric toothbrush according to a proposed embodiment. [Diagram 2] FIG. 2 shows a modification of the embodiment of FIG. [Diagram 3] FIG. 3 is a simplified block diagram of a smart toothbrush device according to another embodiment. [Figure 4] FIG. 4 is a simplified flow diagram of a method for controlling a personal care device, according to an embodiment. [Diagram 5] FIG. 5 is a simplified block diagram of a computer in which one or more portions of the embodiments may be employed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The present invention will now be described with reference to the drawings.

[0036] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the devices, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects and advantages of the devices, systems and methods of the present invention will become better understood from the following description, the appended claims and the accompanying drawings. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0037] Variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and singular elements do not exclude a plurality.

[0038] It should be understood that the figures are only schematic and are not drawn to scale, and that the same reference numerals are used throughout the figures to indicate the same or similar parts.

[0039] The present invention proposes concepts for assisting and / or improving cleaning from a vibrating personal care device. In particular, embodiments provide systems, apparatus and / or methods that provide a process for vibratory control of the mechanical properties and / or motion of toothbrush bristles. This allows the vibrating personal care device to optimize the mechanical properties and / or motion of the cleaning elements depending on the context of use, which can for example enhance cleaning function and results.

[0040] The proposed concepts apply, for example, to powered toothbrushes or mouthpiece-type toothbrushes (where bristle alignment can be a special problem), and embodiments may also employ dedicated vibration-enhancing structures (to enable special use cases such as simultaneous interdental and conventional brushing, or vibration-enhanced tongue cleaning).

[0041] Thus, embodiments can facilitate extending and / or improving the cleaning capabilities of a vibratory personal care device. Such embodiments are particularly relevant to remote dental treatment offerings, for example, by allowing control and / or adaptation of the mechanical properties of the cleaning element depending on the use. For example, the vibration frequency of the device is controlled based on the force applied to the cleaning element during use to obtain desired mechanical properties and / or movement of the cleaning element.

[0042] Referring to Figure 1, there is shown a simplified schematic block diagram of an electric toothbrush 10 according to a proposed embodiment. The electric toothbrush 10 comprises a brush head 13 supporting a plurality of bristles 14 (i.e. cleaning elements 14) for engagement with a user's oral surfaces. The toothbrush also comprises vibration means 12 (specifically a motor) adapted during use to vibrate the brush head 13 (and thus the bristles 14) of the electric toothbrush 10 over a range of different vibration frequencies (e.g. 25Hz-1kHz).

[0043] The toothbrush 10 further includes a pressure sensor 16 that senses a load force applied to the bristles 14 by engagement with a surface of the user's oral cavity, where the pressure sensor 16 senses / detects a magnitude value of the load force and a directional value of the load force.

[0044] The toothbrush 10 also includes a control unit 18 that determines a target frequency based on the sensed loading force applied to the bristles 14 and cleaning element data describing one or more physical characteristics of the cleaning elements / bristles 14, and controls the vibration means 12 based on the target frequency. In particular, the control unit 18 determines the target frequency based on a magnitude and / or direction of the sensed loading force to achieve a desired mechanical response of the bristles 14 and / or a preferred direction of movement of the bristles 14. In other words, the target frequency causes at least one of the mechanical response of the cleaning elements / bristles 14 or the direction of movement of the cleaning elements / bristles 14 to change.

[0045] 1, the control unit 18 includes a communications interface 22 for obtaining cleaning element data describing one or more physical characteristics of the bristles 14. In particular, the communications interface 22 provides a wireless connection to a database of cleaning element data describing one or more physical characteristics of various toothbrush bristles 14, such as shape, type, size, cross-sectional area, arrangement, material, stiffness, length, number of bristles per unit area, and attachment angle.

[0046] As an example, the wireless connection includes a short-medium range communication link. For the avoidance of doubt, a short-medium range communication link should be interpreted as meaning a short-range or medium-range communication link having a distance of up to about 100 meters. In a short-range communication link designed for a very short communication distance, the signal typically travels from a few centimeters to a few meters, whereas in a medium-range communication link designed for a short-medium communication distance, the signal typically travels up to 100 meters. Examples of short-range wireless communication links include ANT+, Bluetooth, Bluetooth Low Energy, IEEE802.15.4, ISA100a, Infrared (IrDA), ISM bands, Near Field Communication (NFC), RFID, 6LoWPAN, UWB, WirelessHART, WirelessHD, WirelessUSB, and ZigBee. Examples of medium-range communication links include Wi-Fi, Z-Wave.

[0047] Thus, the communication interface 22 retrieves the cleaning element data from a database implemented in a remotely accessible data storage unit. In this way, information toothbrush 10 can be retrieved / obtained by the control unit 18.

[0048] Using information regarding the physical characteristics of particular bristles 14 of toothbrush 10, together with the sensed magnitude and / or direction of the load force applied to the bristles 14, control unit 18 determines a target frequency such that the bristles 14 exhibit desired mechanical properties (such as reduced stiffness) and / or direction of movement when vibrated at the target frequency.

[0049] In this way, the sensed magnitude and / or direction of the load force can be used together with the known properties of the bristles 14 to calculate (by the control unit 18) a target vibration frequency that is expected to lead to a desired mechanical response of the bristles 14 and / or a preferred direction of movement of the bristles 14. The control unit 18 then adjusts the drive frequency of the vibration means 12 accordingly.

[0050] Thus, the vibration means 12 can be controlled to achieve a target mechanical response and / or direction of movement of the bristles 14, potentially improving the cleaning action and, for example, reducing the amount of undesired tissue damage.

[0051] Although the embodiment of FIG. 1 has been described above with reference to the vibratory motion of toothbrush bristles, the proposed concept can also be adopted in other vibrating personal care devices exhibiting vibration of a cleaning element.

[0052] Also, while the embodiment of FIG. 1 employs the concept of employing a loading force applied to the bristles, other parameters of the personal care device can also be monitored to refine or improve the control of the vibration frequency. Examples of other parameters that can be monitored include device position, device movement, magnetic field, and contact surface. Thus, simple detection of the operating parameters of the personal care device to determine a preferred, optimal, or target vibration frequency can be employed to improve or optimize cleaning.

[0053] By way of example only, a modified version of the embodiment of Figure 1 is shown in Figure 2. In the embodiment of Figure 2, the toothbrush 100 further includes a position sensor 20 for sensing the positioning of the bristles 14. Such a sensor 20 may employ a gyroscope, compass, or other angle-sensing device. The sensor 20 may also include an accelerometer sensor positioned in the handle of the toothbrush 10.

[0054] In this case, the control unit 18 determines the target frequency further based on the sensed position of the bristles. For example, the control unit determines a target direction for the bristles 14 based on the sensed position of the bristles 14. The control unit 18 then determines a target frequency based on the target direction (which achieves a desired direction of movement of the bristles 14).

[0055] In another exemplary embodiment, the toothbrush 10 identifies a surface of the user that the bristles engage during use (e.g., based on a sensed position of the bristles). This identified surface of the user may be used to determine a target frequency based further on the identified surface. For example, this may result in a desired direction of movement of the bristles 14 and / or a desired mechanical response (e.g., increased or decreased stiffness, etc.).

[0056] Furthermore, although embodiments have been described above with reference to determining a single target frequency, it is proposed to adapt the embodiments to determine a mixture of target frequencies (i.e. multiple different frequencies) to provide a desired mechanical response and / or direction of movement of the bristles, for example taking into account sensed load forces applied to different subsets of bristles.

[0057] In another exemplary embodiment, the effectiveness of vibrating bristle actuation is further enhanced by including specially designed structures (such as 3D printed bristles) with enhanced mechanical vibration response at known locations.

[0058] By way of further explanation of the proposed concept, the main steps of the embodiment when applied to a conventional electric toothbrush are summarized below: (I) (For replaceable-head brushes) The toothbrush registers which brush head is attached and obtains its characteristics from a (cleaning element) database that describes the physical characteristics of the bristles of different toothbrush heads, including size, shape, and type and arrangement of bristles. (II) The user turns on the toothbrush and begins brushing. The brush's inertial sensor is used to track the position of the brush head in the user's mouth in a conventional manner. (III) The amount of pressure applied by the user to the bristles is measured by a brushhead pressure sensor, and the direction of the pressure applied to the brushhead and bristles is either measured directly or calculated from the size and position of the brushhead in the mouth. (IV) The pressure difference across the area of ​​the brushhead is calculated from the measurements taken in (III) and the known brushhead characteristics. If the pressure applied to different bristles or groups of bristles is asymmetric (which is expected in the majority of situations), the method proceeds to the next step (V). If proper pressure asymmetry is not detected, the system may guide or warn the user or attempt to modify the bristle characteristics across the brushhead (by controlling the frequency of the toothbrush). (V) The toothbrush calculates the desired bristle stiffness or direction of movement from the current position in the mouth, or the desired characteristics may be constant or manually input. (VI) The brush calculates a target frequency (or mix of frequencies) that is expected to achieve the desired bristle characteristics given the pressure asymmetry from (IV) and the desired bristle characteristics from (V). The target frequency / frequencies are then used to control the toothbrush motor. This calculation can be further modified by considering achievable inputs from the available motor hardware, so that if the ideal characteristics are not achievable, the toothbrush can at least partially achieve them. (VII) Steps (III)-(VI) are repeated as the user completes a brushing session, given the changing inputs of pressure and position, to calculate updated desired bristle characteristics, and therefore updated target frequencies.

[0059] 3, there is shown a simplified block diagram of a smart toothbrush device 40 according to another embodiment. The toothbrush 40 is inserted into a user's mouth and vibrates (in use) for oral cleaning.

[0060] Toothbrush 40 includes several hardware components common to conventional powered oscillating toothbrushes, including, in particular: - A toothbrush head (or "brush head") 42, which may be permanently fixed or changeable by the user, and includes at least one group (tuft) of cleaning elements (such as bristles) at or near the distal end that contacts the teeth during brushing. In some embodiments (such as mouthpiece toothbrushes), the cleaning elements may be located throughout the brush head, rather than just at the distal end. The brush head 42 may include one or more structures (i.e., "vibration enhancement structures") either at the distal end or throughout (in the case of mouthpiece toothbrushes) that are designed to be highly responsive to mechanical vibrations to enhance vibration control. An example of such a vibration enhancement structure is a 3D printed hair-like fiber with a cross-sectional area that varies along the length of the fiber to enhance control via vibration input of known frequencies. Such vibration enhancement structures are particularly relevant for specialized tasks such as interdental brushing and tongue cleaning. A motor 44 that drives the vibration of the brush head 42. The motor 44 generates a sonic, ultrasonic, vibratory rotation, or other vibration or mechanical input to the brush head 42. - A head sensor that detects the type of brush head that is attached (i.e., a "head type sensor") 46. Several types of such head sensors are commonly known and are expected to be suitable, including wireless or wired sensors. - At least one pressure sensor (i.e., "head pressure sensor") 48 that measures the pressure applied by the user to the brush head during brushing. Suitable hardware may include any type of strain gauge, other force sensor, or mechanical position sensor disposed within the toothbrush body such that load forces applied to the distal end of the brush head are transmitted and detected. Alternatively, the brush head may have a pressure sensing element directly at the distal end. In a mouthpiece-type toothbrush, there may be an optional additional hardware ("clamp sensor") 50 - a clamp-type sensor that measures the force applied by a mechanical clamp component such as a spring. The pressure sensor is preferably composed of multiple sub-sensors disposed at different locations around the toothbrush 40 so that directional forces can be detected and resolved. - Hardware for measuring the position of the toothbrush in space ("Inertial Measurement Unit") 52. Such hardware may include accelerometers, gyroscopes, and / or magnetometers, etc. - A central processing unit ("Processing and Connectivity Unit") 54 with appropriate memory hardware and (optionally) appropriate network hardware to enable the toothbrush to collect, store, and analyze data from all connected hardware components, send control signals to the motor, and communicate wirelessly (e.g., via WiFi, Bluetooth, 5G).

[0061] The embodiment of Figure 3 also employs a set of algorithms that are executed locally within the processing and connectivity unit 54 or accessed remotely via another nearby device (e.g. a smartphone) or via a cloud service. The set of algorithms includes: - A first algorithm ("Mouth Mapping Algorithm") 60 for relating position data from the inertial measurement unit 52 to a generic or user-specific mouth model to estimate the relative position of the brush head 42 with respect to relevant structures in the mouth, such as the teeth, gums, etc. (hereinafter referred to as the "intra-oral position"). - A second algorithm for calculating ideal / desired cleaning element properties for a given usage scenario and in-mouth location ("bristle property algorithm") 62. Bristle properties include stiffness and / or direction of motion and may be spatially resolved within an area of ​​the brush head or may be uniform across that area. - A third algorithm ("bristle actuation algorithm") 64 for calculating the frequency input required to achieve the desired cleaning element characteristics.

[0062] The embodiment of Figure 3 further employs a database ("head type database") 66 that contains characteristics associated with brush heads, such as: (a) physical characteristics of different common brush head types or models, and (b) characteristics of specific brush heads, such as time of use and / or wear characteristics. The head type database 66 is stored locally within the processing and connectivity unit 54 or accessed remotely on another nearby device (e.g., a smartphone) or via a cloud service.

[0063] The embodiment of Figure 3 also includes a second database ("User Database") 68 that contains characteristics specific to a particular user, such as unique oral and dental anatomy, dental health goals, presence of implants or orthodontic appliances, etc. The User Database 68 may be stored locally within the processing and connectivity unit 54 or accessed remotely on another nearby device (e.g., a smartphone) or via a cloud service, although local storage is preferred due to privacy / safety concerns.

[0064] Referring now to Figure 4, there is shown a simplified flow diagram of a method 70 for controlling a personal care device, according to an embodiment of the present invention. In this example, the personal care device is a mouthpiece for insertion into a user's oral cavity. The mouthpiece includes a number of cleaning elements that protrude from a support surface of the mouthpiece for engaging the oral surfaces of the user in use. The mouthpiece also includes vibration means (such as a motor with an offset cam) for vibrating the cleaning elements at different frequency ranges. The mouthpiece also includes a pressure sensor that senses / detects a load force in use.

[0065] The method includes an initial step 72 of sensing, with a pressure sensor, a load force applied to at least a first subset of the cleaning elements by a user's engagement with a surface.

[0066] The method then proceeds to step 74 of determining a target frequency based on the sensed load force applied to at least the first subset of cleaning elements, where step 74 includes using one or more algorithms (such as those described above) to determine a target frequency to achieve desired characteristics of the cleaning elements (such as a desired stiffness and / or direction of movement).

[0067] Finally, in step 76, the vibration means is controlled based on the target frequency, for example, the frequency of the vibration means is set to be substantially equal to the target frequency.

[0068] With further explanation of the proposed control method, an exemplary process for vibration control of the mechanical properties and / or motion of cleaning elements of a personal care device is now described below, which is designed to enable a personal care device (such as a toothbrush, a mouthpiece toothbrush, or a skin cleaning brush) to optimize the mechanical properties and / or motion of cleaning elements (bristles, protuberances, nodes, protuberances, etc.) depending on the current usage situation.

[0069] (I) The user turns on the device and starts a cleaning / brushing session. The device checks, via a sensor, that a cleaning element is attached. If the cleaning element has been replaced since the previous session (e.g., the brush head has been replaced), the device collects details of the cleaning element and retrieves its physical characteristics from a database. Examples of retrieved physical characteristics include overall length, placement of the cleaning element, length of the cleaning element, material of the cleaning element, presence of vibration enhancing structures, etc. If the cleaning element has not been replaced (e.g., still has the same brush head as in the previous session), the device increments the usage count by one and retrieves the same characteristics as in the previous session from the database.

[0070] If a characteristic cannot be obtained, the device may warn the user or request manual input. The newly collected characteristics are stored in the appropriate area of ​​the database.

[0071] (II) The user continues the cleaning / brushing session. The device's position is tracked via position / movement sensors and the tracking data is passed to the control unit, which runs or accesses a first algorithm to determine the in-mouth position of the device (such as the Mouth Mapping algorithm of FIG. 3). Here, the first algorithm calculates the in-mouth position using known techniques such as pedestrian dead reckoning. This is augmented by the use of calibration points at known locations.

[0072] In addition, the first algorithm uses pressure data (measured simultaneously, as described in the next step) to improve accuracy. For example, the force or direction of pressure applied by a user forms repeatable patterns in similar areas of the oral cavity over time. The first algorithm uses these points of known or expected pressure as (additional) calibration points of known location to enhance the location estimation.

[0073] The mouth location is passed to a second algorithm to calculate the ideal / desired cleaning element characteristics for the given usage situation and mouth location (such as the bristle characteristics algorithm of FIG. 3).

[0074] (III) Concurrently with (II) above, the load force applied by the user to the cleaning element is measured by a sensor. The sensed load force data is passed to the control, where both the magnitude and direction of the force applied by the user to the cleaning element are measured or calculated. Depending on the available hardware, the pressure force is either (a) measured directly (in which case the device may require a sensor that can resolve both force and direction) or (b) inferred (in which case the force is measured by a single-axis sensor and an expected fit to the teeth or gums is used to resolve the ambiguity of direction). This is not necessary for device geometries that facilitate direct pressure measurement, such as mouthpiece-type toothbrushes.

[0075] The pressure magnitude and direction of the loading force applied to the cleaning element is passed to a third algorithm (such as the bristle actuation algorithm of FIG. 3) to calculate the frequency input required to achieve the desired cleaning element characteristics.

[0076] (IV) A second algorithm uses the intra-oral positions to calculate a set of desired cleaning element properties, which may include: (a) a global property change such as increased vibration amplitude or increased stiffness, (b) a local property change such as an increase or decrease in effective stiffness or a preferred direction of movement in a particular region / subset of the cleaning element, and (c) an overall preferred direction of movement of the cleaning element.

[0077] The in-mouth position is used to calculate target / desired values ​​of cleaning element properties, which may also be augmented by any unique user data available, for example, from a user database.

[0078] For example, if the intra-oral position indicates that a first subset of cleaning elements is above the user's gums and a second subset of cleaning elements is positioned above the user's teeth, it may be desirable for the first subset of cleaning elements positioned above the gums to be softened to avoid abrasion of the gums.

[0079] As a second example, if a user is wearing orthodontic appliances and the intra-oral position indicates that the cleaning element is close to the orthodontic appliances, it may be desirable for the cleaning element to exhibit a direction of movement that acts to move the device away from the orthodontic appliances and / or move foreign matter away from the intricate structures of the orthodontic appliances, thus enhancing cleaning. This may employ unique user data related to the presence and position of the orthodontic appliances, which may be obtained, for example, from a user database.

[0080] The target / desired value of the cleaning element characteristic is passed to a third algorithm (such as the bristle actuation algorithm of FIG. 3) to calculate the frequency input required to achieve the desired cleaning element characteristic.

[0081] (V) A third algorithm examines the pressure magnitude and direction of the loading force (from step (III) above) and calculates the asymmetry. According to the asymmetry of the applied force, the resulting cleaning element characteristic, and the target / desired value of the cleaning element characteristic (from step (IV) above), the third algorithm calculates one or more target frequencies that are expected to achieve (or partially achieve) the desired characteristic.

[0082] Here, force asymmetry is used to refer to different levels of force applied to different cleaning elements of the device depending on their location in / on the device. If proper pressure asymmetry is not detected, the system can: wait until proper asymmetry is detected, guide or alert the user to achieve asymmetric force, apply a spatially unresolved input to the entire cleaning element (e.g., a global hardening or softening input), or activate other vibrationally responsive structures contained in / on the device.

[0083] A third algorithm calculates the expected frequency response of the cleaning element given the measured forces as a function of the position of the cleaning element in / on the device. This calculation is based on treating the forces as damping forces applied to a system undergoing forced vibration and can proceed analytically or empirically.

[0084] As an example, the following analytical calculations can be employed: The third algorithm is to calculate the damped natural frequencies ω of the cleaning elements in different regions of the device given a known undamped natural frequency ω (from a database). d is calculated using the following formula (i):

number

[0085] The analytical calculations detailed in the paragraph above may fail when there are many non-ideal characteristics of the system (such as poor vibration transmission through the cleaning element attachment to the support surface, or large manufacturing variations that affect the natural frequency of the cleaning elements). In this case, an empirical method is used in which the average response of a given collection of cleaning elements (e.g., brush head type) to a given combination of applied force magnitude and direction and input frequency is measured by experiment, and stored and accessed via a database. The third algorithm can then simply compare the force applied to the cleaning elements at each moment with the empirical results and determine the target frequency determined accordingly.

[0086] This calculation can be repeated for several regions (i.e., subsets) of the cleaning element across the device to calculate the frequency response as a function of position in / on the device. Based on the spatially resolved response data, a third algorithm calculates the target frequency required to achieve the desired cleaning element characteristics.

[0087] If the cleaning element properties require stiffening of some or all of the device, this is accomplished by applying a vibration frequency that results in maximum amplitude vibration. Conversely, softening of some cleaning elements is accomplished by stiffening cleaning elements in other parts of the device (which tends to reduce the component of user applied force that is transmitted through the off-resonance cleaning elements).

[0088] When movement in a particular direction is required, the target frequency can be selected using an asymmetry in the vibration characteristics of the cleaning elements, analytically or empirically derived from a third algorithm, instead of the engineered asymmetry resulting from cleaning elements of different thicknesses.

[0089] If the target vibration frequency calculated by the third algorithm is impractical to apply (e.g. because it is outside the achievable range of the vibration means or because it may be detrimental to the cleaning effect or other task of the device), the expected cleaning element characteristics associated with the closest achievable vibration frequency can be calculated and applied instead. The achievable cleaning element characteristics are checked with the second algorithm to ensure that they remain desired.

[0090] (V) The motor is controlled to impart a target frequency to the cleaning element, the target frequency input being provided either as a modification to the normal brushing motion or (preferably) as an additional secondary input.

[0091] (VII) The above steps are repeated as the user completes a brushing session, given the changing inputs of applied force and position, to calculate updated desired cleaning element characteristics, and therefore updated target frequencies.

[0092] It should be understood that many additional embodiments of the proposed concepts are envisioned, for example through variations of the above embodiments.

[0093] By way of example, modifications are employed to incorporate the use of vibration enhancing structures. Such modifications are intended to enable the use of vibration enhancing structures. These structures have enhanced or known vibration response and are positioned at predefined locations in or on the vibrating personal care device. Such structures are particularly relevant for performing specialized dental tasks such as tongue cleaning and interdental brushing. For example, the above method can be combined with the following modifications to enable the use of vibration enhancing structures:

[0094] In particular, this method proceeds substantially the same as the method above, with the following modifications: In step (I), the location, characteristics and intended use of the vibration enhancement structure are obtained from a database.

[0095] In step (II), the first algorithm cross-references the intraoral locations with the locations and usage of the vibration intensification structures and sets a flag if there is a match. For example, if the device includes vibration intensification structures for interdental cleaning, the first algorithm can set a logical flag to "true" when those locations are expected to overlap with the user's interdental spaces. If the flag is set to true, the second algorithm chooses to activate the vibration intensification structures rather than optimizing the properties of the remaining cleaning elements. In this case, the third algorithm can simply retrieve the associated drive frequency for the vibration intensification structures from a database. As with normal cleaning elements, the frequency can be further modified depending on the force applied by the user.

[0096] In some cases, the user may intentionally place the device in a mode where only the vibration enhancement structure is used (e.g. if the rear of the device includes such structures for enhanced / alternative cleaning). In this case, the user is guided to achieve the correct relative intra-oral position (i.e. the flag in step (II) remains set to "true"). The vibration means is then controlled to apply the associated target frequency as long as the vibration enhancement structure is in the intended location (or until it is disabled by the user).

[0097] As a further example, modifications specific to the use of a mouthpiece-style toothbrush may be employed. For example, the above method may be combined with the following modifications to allow for the use of a mouthpiece-style toothbrush:

[0098] In particular, this method proceeds substantially the same as the method above, with the following modifications: In step (II), a first algorithm calculates the fit of the mouthpiece toothbrush to the user's mouth (not just the location of the device in the mouth), which may include parameters such as the distance from any group of cleaning elements to the teeth, and the alignment of the groups of cleaning elements with the user's teeth, gums, and interdental spaces.

[0099] Since a user does not normally move such a device around the mouth, this fit is expected to remain substantially the same throughout a brushing session, although any changes are monitored by the position sensor.

[0100] In step (III), the pressure measurements are altered. Pressure is applied by a spring or clamping force from the mouthpiece toothbrush itself, in which case it is likely measured directly by hardware local to the spring (i.e., a clamp sensor). If pressure is applied by the user (e.g., by "biting" on the mouthpiece toothbrush), the pressure is measured by one or more additional pressure sensors mounted within the mouthpiece toothbrush. In this case, the pressure measurements can be enhanced by comparing the user's unique dental anatomy with the physical design of the mouthpiece to identify expected "hot spots" of pressure (e.g., due to teeth being at a greater angle to the cleaning elements of the mouthpiece toothbrush, which may locally increase pressure on the cleaning elements).

[0101] In steps (IV) and (V), the second and third algorithms sequentially calculate the desired cleaning element characteristics and associated target frequencies for different parts of the mouthpiece toothbrush, rather than calculating for the entire mouthpiece. This allows for finer control over the various groups of cleaning elements within the mouthpiece, which are expected to be attached at different angles and locations relative to the teeth and therefore experience different levels of pressure (and have different ideal characteristics). By calculating respective cleaning element characteristics and target frequencies for different groups of cleaning elements, such an embodiment can apply locally optimal input frequencies while requiring only a simple vibration means (e.g., a single motor).

[0102] From the above description of various concepts and embodiments, it will be understood that a method of controlling a personal care device is proposed. The personal care device includes a plurality of cleaning elements for engagement with a surface of a user, a vibration means for vibrating the cleaning elements at different frequency ranges, and a pressure sensor. The method includes sensing a load force applied to at least a first subset of the cleaning elements by engagement with a surface of a user using the pressure sensor, determining a target vibration frequency based on the sensed load force applied to at least the first subset of the cleaning elements, and controlling the vibration means based on the target vibration frequency. Such a method may be used in a processing system or computer. And such a system / computer may be incorporated in a vibrating personal care device.

[0103] 6 illustrates an example of a computer 80 in which one or more portions of the embodiments may be used. The various operations described above utilize the functionality of the computer 80. For example, one or more portions of the system for controlling personal care devices may be incorporated into any of the elements, modules, applications, and / or components described herein. In this regard, it should be understood that the functional blocks of the system may operate on a single computer or may be distributed across several computers and locations (e.g., connected via the Internet), such as a cloud-based computing infrastructure.

[0104] The computer 80 may include, but is not limited to, a PC, a workstation, a laptop, a PDA, a palm device, a server, storage, and the like. In general, with respect to a hardware architecture, the computer 80 includes one or more processors 81, a memory 82, and one or more I / O devices 83 communicatively coupled via a local interface (not shown). The local interface may be, for example, but not limited to, one or more buses or other wired or wireless connections as known in the art. The local interface may have controllers, buffers (caches), drivers, repeaters, and receivers to enable communication. Additionally, the local interface may include address, control, and / or data connections to enable appropriate communication between the aforementioned components.

[0105] Processor 81 is a hardware device that executes software that may be stored in memory 82. Processor 81 may be virtually any custom or commercially available processor, central processing unit (CPU), digital signal processor (DSP), or coprocessor of multiple processors associated with computer 80, and processor 81 may be a semiconductor-based microprocessor (in the form of a microchip) or microprocessor.

[0106] The memory 82 may include any one or combination of volatile memory elements (e.g., random access memory (RAM), such as dynamic random access memory (DRAM), static random access memory (SRAM), and non-volatile memory elements (e.g., ROM, erasable programmable read only memory (EPROM), electronically erasable programmable read only memory EEPROM), programmable read only memory (PROM), tape, compact disk read only memory (CD-ROM), disk, diskette, cartridge, cassette, and the like). Additionally, the memory 82 may incorporate electronic, magnetic, optical, and / or other types of storage media. It is noted that the memory 82 may have a distributed architecture in which various components are remote from one another but accessible by the processor 81.

[0107] The software in memory 82 may include one or more separate programs, each including an ordered list of executable instructions for implementing logical functions. The software in memory 82 includes a suitable operating system (O / S) 84, a compiler 86, source code 85, and one or more applications 87, according to an exemplary embodiment. As shown, application 87 includes a number of functional components for implementing the features and operations of the exemplary embodiments. The application 87 of computer 80 may represent various applications, computing units, logic circuits, functional units, processes, operations, virtual entities, and / or modules, according to an exemplary embodiment, although application 87 is not intended to be limiting.

[0108] Operating system 84 controls the execution of other computer programs and provides scheduling, input / output control, file and data management, memory management, and communication control and related services. The inventors contemplate that application 87 for implementing the exemplary embodiment is applicable to any commercially available operating system.

[0109] The application 87 may be a source program, an executable program (object code), a script, or any other entity that includes a set of instructions to be executed. In the case of a source program, the program is typically translated via a compiler (such as compiler 86), assembler, interpreter, etc., which may or may not be contained in memory 82, so that it operates properly in conjunction with the O / S 84. Additionally, the application 87 may be written as an object-oriented programming language with classes of data and methods, or a procedural programming language (e.g., but not limited to, C, C++, C#, Pascal, BASIC, API calls, HTML, XHTML, XML, ASP script, JavaScript, FORTRAN, COBOL, Perl, Java, ADA, .NET, etc.) with routines, subroutines, and / or functions.

[0110] The I / O devices 83 include input devices such as, but not limited to, a mouse, keyboard, scanner, microphone, camera, etc. The I / O devices 83 also include output devices such as, but not limited to, a printer, display, etc. Finally, the I / O devices 83 also include devices that communicate both input and output such as, but not limited to, a NIC or modulator / demodulator (for accessing remote devices, other files, devices, systems, or networks), radio frequency (RF) or other transceivers, telephone interfaces, bridges, routers, etc. The I / O devices 83 also include components for communicating over various networks such as the Internet or an intranet.

[0111] If computer 80 is a PC, workstation, intelligent device, etc., the software in memory 82 may further include a Basic Input / Output System (BIOS) (omitted for simplicity). The BIOS is a set of essential software routines that initializes and tests the hardware at power-on, starts O / S 84, and supports data transfer between hardware devices. The BIOS is stored in some type of read-only memory, such as ROM, PROM, EPROM, EEPROM, etc., so that it is executable when computer 80 is powered on.

[0112] During operation of computer 80, processor 81 executes software stored in memory 82, transfers data to and from memory 82, and generally controls the operation of computer 80 in accordance with the software. Applications 87 and O / S 84, in whole or in part, are read by processor 81 and, in some cases, buffered within processor 81 before being executed.

[0113] It should be noted that if the application 87 is implemented in software, the application 87 may be stored on virtually any computer-readable medium for use with or in connection with any computer-related system or method. In the context of this document, a computer-readable medium may be an electronic, magnetic, optical, or other physical device or means that can store or retain a computer program for use with or in connection with a computer-related system or method.

[0114] The application 87 may be embodied in any computer-readable medium for use with or in connection with an instruction execution system, apparatus, or device (such as a computer-based system, processor-based system, or other system that can fetch instructions from and execute instructions from an instruction execution system, apparatus, or device). In the context of this document, a "computer-readable medium" may be any means that can store, communicate, propagate, or transfer a program for use with or in connection with an instruction execution system, apparatus, or device. Computer-readable media include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, devices, or propagation media.

[0115] The proposed control method may be implemented in hardware or software, or a combination of both (e.g., as firmware running on a hardware device). To the extent that the embodiment is implemented partially or fully in software, the functional steps illustrated in the process flow charts may be performed by one or more appropriately programmed physical computing devices, such as central processing units (CPUs) or graphics processing units (GPUs). Each process (and the individual component steps illustrated in the flow charts) may be performed by the same or different computing devices. According to an embodiment, a computer-readable storage medium stores a computer program including computer program code that, when the program is executed on one or more physical computing devices, causes the one or more physical computing devices to perform the control method as described above.

[0116] The storage media may include volatile and non-volatile computer memories such as RAM, PROM, EPROM, and EEPROM, optical disks (such as CDs, DVDs, BDs, etc.), and magnetic storage media (such as hard disks and tapes). Various storage media may be fixed within a computing device or may be transportable so that one or more programs stored thereon may be loaded into a processor.

[0117] To the extent that the embodiments are implemented in part or in whole in hardware, the blocks shown in the block diagrams of Figures 1, 2, and 3 may be separate physical components, logical subdivisions of a single physical component, or may be integrated and all implemented in one physical component. The functionality of a block shown in the figures may be split among multiple components in the implementation, or the functionality of multiple blocks shown in the figures may be combined into a single component in the implementation. Examples of hardware components suitable for use in the embodiments of the present invention include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field programmable gate arrays (FPGAs). One or more blocks may be implemented as a combination of dedicated hardware for performing some functions and one or more programmed microprocessors and associated circuitry for performing other functions.

[0118] Variations of the disclosed embodiments can be understood and effected by those skilled in the art in implementing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the singular elements do not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain means are recited in mutually different dependent claims does not indicate that a combination of these means cannot be used to advantage. In the case where a computer program is described above, it can be stored / distributed on any suitable medium, such as an optical storage medium or a solid-state medium, provided together with or as part of other hardware, but can also be distributed in other forms, such as via the Internet or other wired or wireless communication systems. It should be noted that when the term "adapted to" is used in the claims or description, the term "adapted to" is intended to be equivalent to the term "configured to". Any reference signs in the claims should not be interpreted as limiting the scope.

[0119] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowcharts or block diagrams may represent a module, segment, or part of instructions that includes one or more executable instructions for implementing a specified logical function(s). In some alternative implementations, the functions shown in the blocks may occur out of the order shown in the figures. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or these blocks may be executed in reverse order depending on the functionality involved. It should also be noted that each block of the block diagrams and / or flowchart diagrams, and combinations of blocks in the block diagrams and / or flowchart diagrams, may be implemented by a special-purpose hardware-based system that performs the specified functions or acts or executes a combination of special-purpose hardware and computer instructions.

Claims

1. a plurality of cleaning elements for engagement with a surface of a user; vibrating means for vibrating said cleaning element at a range of different frequencies; a pressure sensor that senses a load force applied to at least a first subset of the cleaning elements by the user's engagement with the surface; a control unit; The control unit determining a target frequency based on the sensed load force applied to the at least a first subset of the cleaning elements and cleaning element data describing one or more physical characteristics of the cleaning elements, the target frequency affecting at least one of a mechanical response of the cleaning elements or a direction of movement of the cleaning elements; controlling the vibration means based on the target vibration frequency; , a personal care device.

2. a position sensor for sensing a positioning of at least a subset of the plurality of cleaning elements; The personal care device of claim 1 , wherein the control unit determines the target frequency further based on the sensed positions of the at least a first subset of the cleaning elements.

3. 3. The personal care device of claim 2, wherein the control unit determines a target direction based on the sensed positions of the at least a first subset of the cleaning elements and determines the target frequency based on the determined target direction.

4. 4. The personal care device of claim 2 or 3, wherein the control unit further identifies, in use, a surface of the user engaged by the plurality of cleaning elements based on the sensed positions of the at least a first subset of the cleaning elements, and determines the target frequency further based on the identified surface of the user.

5. The personal care device of claim 1 , wherein the control unit includes a communication interface for obtaining the cleaning element data of the cleaning element.

6. 6. The personal care device of claim 5, wherein the communication interface retrieves the cleaning element data from a database of cleaning element data, optionally implemented at least in part in a remotely accessible data storage unit.

7. 7. The personal care device of claim 1, wherein the one or more physical characteristics of the cleaning elements include at least one of shape, type, size, cross-sectional area, arrangement, material, stiffness, length, number of bristles per unit area, and attachment angle.

8. 8. The personal care device of claim 1, wherein the control unit is further adapted to determine a second target frequency based on the sensed load force applied to the at least first subset of the cleaning elements and to control the vibration means based on the second target frequency.

9. the pressure sensor further senses a load force applied to a second, different subset of the cleaning elements by the user's engagement with the surface; 9. The personal care device of claim 1, wherein the control unit is further adapted to determine a third target frequency based on the sensed load force applied to the second subset of the cleaning elements and to control the vibration means based on the third target frequency.

10. 10. The personal care device of claim 1, wherein the sensed load force includes at least one of a magnitude value and a directional value, and the control unit determines the target frequency based on the at least one of a magnitude value and a directional value.

11. 11. The personal care device of claim 1, wherein the at least a first subset of the plurality of cleaning elements comprises a vibration-enhancing structure configured to have predetermined mechanical properties in response to being vibrated at a predetermined excitation frequency.

12. The vibration enhancement structure includes: an elongated bristles having different cross-sectional shapes and / or sizes at at least two different positions along a longitudinal length of the bristles; an elongate structure attached to the personal care device with an angular bias; and an elongate bristles formed of different materials at at least two different locations along the longitudinal length of said bristles; 12. The personal care device of claim 11, comprising at least one of:

13. 13. A personal care device according to any one of the preceding claims, comprising a toothbrush, a mouthpiece or a skin cleaning brush.

14. 1. A method of controlling a personal care device, the personal care device including a plurality of cleaning elements for engagement with a surface of a user, vibration means for vibrating the cleaning elements at different frequency ranges, and a pressure sensor, the method comprising: sensing, with the pressure sensor, a load force applied to at least a first subset of the cleaning elements by the user's engagement with the surface; determining a target frequency based on the sensed load force applied to the at least a first subset of the cleaning elements and cleaning element data describing one or more physical characteristics of the cleaning elements, the target frequency affecting at least one of a mechanical response of the cleaning elements or a direction of movement of the cleaning elements; controlling the vibration means based on the target frequency; A method comprising:

15. A computer program comprising computer program code means for performing the method of claim 14 when the computer program is run on a computer.

Images