Personal care device

Abstract

According to this disclosure, a personal care device includes a handle portion enabling a user to grasp the personal care device with their hand; a head portion for providing personal care treatment to a personal care area, the head portion being detachably attached to the handle portion; a drive unit having a motor for driving and moving at least a portion of the head portion; and a controller arranged and / or configured to (a) provide a periodic drive signal to the motor, the periodic drive function being adaptable by an inherently controllable weighting coefficient, (b) determine at least one phase shift value between the periodic drive signal and a periodic motor response signal, and (c) determine, based on the determined phase shift value, (c1) whether the head portion is attached to the handle portion and / or (c2) the type of head portion attached to the handle portion and / or (c3) the wear condition of the head portion attached to the handle portion.

Description

[Technical Field]

[0001] This disclosure relates to a personal care device comprising a handle portion and a removable head portion, wherein the handle portion comprises a drive unit for driving and moving at least a portion of the head portion and a controller for providing a periodic drive signal to the motor of the drive unit. [Background technology]

[0002] It is generally known that information regarding the mounting status of a reusable and removable head of a personal care device can support further functionality of the personal care device and / or be used to improve the user experience when using the personal care device. U.S. Patent No. 11 058 525(B2) generally describes the detection of mounting or removal operations by analyzing motor signals caused by the removal or mounting operation. The mounting status detection described herein requires that motor signals are constantly monitored, i.e., monitored even when the motor is not operating. This is due to the fact that the mounting or removal operation itself will be identified based on the effect these operations have on the motor. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] U.S. Patent No. 11 058 525(B2) [Overview of the project] [Problems that the invention aims to solve]

[0004] Therefore, an object of the present invention is, in particular, to provide a personal care device in which the mounting state of the removable head portion of the personal care device can be determined without the need to monitor motor signals, even when the personal care device is switched off. [Means for solving the problem]

[0005] According to at least one embodiment, the personal care device comprises a handle portion enabling a user to grasp the personal care device with their hand; a head portion for providing personal care treatment to a personal care area, the head portion being detachably attached to the handle portion; a drive unit comprising a motor for driving and moving at least a portion of the head portion; and a controller arranged and / or configured to (a) provide a periodic drive signal to the motor, the periodic drive function being adaptable by an inherently controllable weighting coefficient; (b) determine at least one phase shift value between the periodic drive signal and a periodic motor response signal; and (c) determine, based on the determined phase shift value, (c1) whether the head portion is attached to the handle portion and / or (c2) the type of head portion attached to the handle portion and / or (c3) the wear condition of the head portion attached to the handle portion. [Brief explanation of the drawing]

[0006] This disclosure will be further clarified by a detailed description of exemplary embodiments and reference to the figures. [Figure 1] This is a diagram illustrating an exemplary personal care device, an electric toothbrush comprising a handle and a detachably attached head. [Figure 2] This is a schematic diagram of the components of the personal care device disclosed herein. [Figure 3A] This is a schematic diagram showing a periodic drive signal over time and two different periodic motor response signals over time. [Figure 3B] This is a schematic diagram showing the time course of three different weighted periodic drive functions. [Figure 4] It is a diagram showing a time-course measurement curve of phase shift values between a periodic drive signal and a periodic motor response signal while a head unit is repeatedly attached to and detached from a handle unit of a personal care device. [Figure 5] It is a diagram of phase shift values measured for three different types of head units depending on the overall weighting factor. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0007] In the context of the present specification, the term "personal care" is intended to mean the growing (or care) of skin and its appendages (i.e., hair and nails), as well as teeth and the oral cavity (including tongue, gums, etc.), which on one hand aims at preventing diseases and maintaining and enhancing health, and on the other hand aims at cosmetic treatment and improving the appearance of skin and its appendages. This includes the maintenance and enhancement of well-being. It includes skincare, hair care, oral care, and nail care. It further includes cosmetic procedures such as beard care, shaving, and hair removal. Accordingly, a "personal care device" means any device for performing such growing or cosmetic procedures, for example, (cosmetic) skin treatment devices such as skin massage devices or skin brushes; wet razors; electric shavers or trimmers; electric epilators; and oral care devices such as manual or electric toothbrushes, (electric) flossers, (electric) irrigators, (electric) tongue cleaners, or (electric) gum massagers. Terms in parentheses indicate optional features. This does not exclude that the proposed personal care device may have more pronounced advantages in one or more of these growing or device areas than in one or more other areas of these areas. An electric toothbrush is selected herein to represent a personal care device. Unless details are specific to an electric toothbrush, the proposed technology and concepts can be used in any other personal care device.

[0008] The present disclosure relates to a personal care device having a handle portion and a head portion that can be repeatedly attached to and detached from the handle portion. A plurality of different head portions and a single handle portion to which one of the different head portions can be selectively attached form a personal care kit according to the present disclosure. The handle portion allows the personal care device to be held by hand. The head portion may comprise one or more structures relevant for providing a personal care treatment, such as one or more filaments, filament tufts, elastomer elements, massage pads, blades, light sources, and / or tweezers, etc. The personal care treatment is provided by a user in a personal care area, for example, the oral cavity for a toothbrush or the lower area of the face for a shaver.

[0009] The personal care device further comprises a drive unit having a motor for driving a part of or the entire head portion to move relative to the handle portion, and a controller for providing a periodic drive signal to the motor. The periodic drive signal is used to provide an adjustable energy level to the motor, and the periodic drive signal may be scaled by increasing or decreasing a weighting factor to adjust the energy level. In operation, the motor generates a measurable periodic motor response signal such as a motor current, a voltage across the motor, a voltage between a motor terminal and a reference voltage, or a signal induced by the motor in a sensor. The frequency of the periodic motor response signal may in particular be the same as the frequency of the periodic drive signal, which of course may be the case when both periodic signals are related to each other, that is, the periodic drive function causes the periodic motor response signal.

[0010] The controller determines at least one phase shift value between the periodic drive function and the periodic motor response signal, and based on the determined at least one phase shift value, the following: (a) the attachment state of the head portion, that is, whether the head portion is attached to the handle portion or not, (b) Types or types of heads attached to a head, which can distinguish at least two different heads, and / or (c) The device is configured and / or arranged to determine one or more of the wear conditions of the mounted head portion, such as the degree of deformation due to long-term use, the degree of wear of mechanically connected elements, etc.

[0011] The controller is as follows: (a) When the personal care device is operating, automatically, (b) Automatically at a specific point in time after the toothbrush is switched on, for example, 10ms after the personal care device is switched on. (c) When the personal care device is operating, it will periodically and automatically perform actions such as every 0.1 seconds, every 1.0 second, or every 10 seconds. (d) For example, when triggered by a user-operable trigger input element such as a button that may be provided on the handle of the personal care device, or by a touch sensor input element provided on a separate device such as a smartphone that is data-connected to the personal care device, (e) While the personal care device is in wake mode, in which the personal care device's motor is not operating, for example, at a specific point in time after wake mode is activated, or periodically during wake mode, or when triggered by a user-operable trigger input element while wake mode is activated, (f) Depending on an operation that moves at least one component of the motor and thus induces a signal to another motor component (as commonly described in U.S. Patent No. 11 058 525(B2)) or a sensor, the operation referred to may be an installation or removal operation, in accordance with at least one of these concepts (understood to be limited and not necessarily complete) to determine a phase shift value between a periodic drive signal and a periodic motor response signal.

[0012] The controller may be configured and / or arranged to provide a periodic drive signal as a pulse-width modulation (PWM) signal, i.e., as a sequence of pulses of the supply voltage, each pulse having an individual length for shaping the current flowing through the motor. The average voltage applied to the motor by the PWM signal may approximate a sinusoidal signal, but other types of periodic signals such as sawtooth signals or rectangular signal sequences are also possible. The periodic drive signal may be dynamically adjusted by the controller to adapt to a changing load in the head, for example, to maintain at least approximately a constant amplitude or constant frequency of motion of at least a portion of the driven head. Adaptation of the periodic drive signal may be achieved by increasing or decreasing a weighting coefficient. In the case of a PWM signal, the individual lengths of the voltage pulses may be increased or decreased by the weighting coefficient. A higher weighting coefficient may result in a higher energy level delivered to the motor by the periodic drive function.

[0013] The controller may be configured and / or arranged to determine at least one phase shift value, specifically two or more phase shift values ​​over time, between a periodic drive function and a periodic motor response signal. According to some examples, multiple phase shift values ​​may be averaged to determine a phase shift value that is less affected by noise or tolerances. The determined phase shift value may be compared to at least one predetermined threshold phase shift value / reference phase shift value and / or at least one predetermined target range of phase shift values. The predetermined threshold phase shift value may be set to enable distinction between whether a head unit is mounted or not. The predetermined threshold phase shift value may be selected to lie between a phase shift value indicating that a head unit is not mounted and another phase shift value indicating that a particular head unit is mounted. Alternatively, the predetermined threshold phase shift value may be selected to lie between a phase shift value indicating that a head unit is not mounted and a cluster of phase shift values ​​associated with multiple different head unit mounting states. At least one predetermined phase shift value target range may be selected such that, for a given head type, the target range ideally includes all phase shift values ​​that can typically occur due to manufacturing tolerances when the head is manufactured, and / or ideally, all phase shift values ​​that can typically occur due to wear effects during the typical life of the given head type.

[0014] The motor of a personal care device may be implemented as a resonant motor, for example, a motor having at least one resonant frequency at which the motor has peak efficiency. A resonant motor may typically comprise a driven armature mounted to be pushed back from a displaced position to a stationary position by a return force, such as a spring force. The resonant frequency of such a motor may depend on various parameters that define the resonant system, such as the inertia or moment of inertia of the driving mass, the total spring constant of one or more springs or other spring-like forces acting in the system to apply a return force to the driving mass, or the total damping of the system. In some embodiments, different heads have different inertia (different masses), different moments of inertia, different damping, and / or different spring constants. Such differences in heads lead to differences in the resonant systems formed by the motor and the different heads coupled thereto. To enable easy distinction between different heads, the head manufacturers may choose to provide different driven masses, different moments of inertia, different damping, and / or different spring constants. In that case, it is possible to initiate a dedicated operation when a specific type of head unit is determined; for example, a specific periodic drive signal may be used for the determined type of head unit.

[0015] In some cases, the phase shift value may indicate that a worn or even damaged head is attached to the handle. Under such a determination, the controller may be configured to at least indicate that the attached head is, for example, worn, or the controller may even interrupt the motor's operation to warn the user of potential danger due to the head being damaged. The controller may then await a confirmation signal from the user that operation should continue.

[0016] The following list of exemplary embodiments provides different heads that result in different resonant characteristics for the entire system, and thus provides some insight into the possibility of distinguishing different heads due to their distinctly distinct phase shift values. - The drive mass is changed by making the wall or other elements thinner or thicker, or by providing at least one hole of varying sizes in at least one mass element driven by a motor. - For example, the total spring constant is changed by providing a spring to the driven mass, for example, a spring to hold the driven mass in a predetermined resting position. -By changing the mass distribution relative to the axis of rotation on which the mass is driven, the moment of inertia of the driven mass that is driven to rotate or vibrate is changed.

[0017] According to some exemplary embodiments, in addition to or instead of the exemplary embodiments described above, a plurality of phase shift values ​​are determined dependent on a weighting coefficient such that the phase shift values ​​depend on the weighting coefficient to represent potentially noisy values ​​of the function. One or more predetermined sets of weighting coefficient-dependent reference phase shift values ​​may be stored in memory accessible by the controller, for example, the memory may be part of the controller. The controller may be configured and / or arranged to compare the set of phase shift values ​​currently determined dependent on the weighting coefficient with one or more of the stored reference sets that enable the determination, for example, the type of head attached to the handle and / or the wear condition of the attached head. The weighting coefficient may be basically in the range of 0% to 100%, or may have lower range values ​​such as 20% and higher range values ​​such as 99%. It is understood that the set of weighting coefficient-dependent phase shift values ​​includes at least two phase shift values ​​with different weighting coefficient values, e.g., a 34% weighting coefficient value and a 66.2% weighting coefficient value. A continuous phase shift function may be determined by a fitting algorithm applied to the set of phase shift values.

[0018] According to this disclosure, the motor of the drive unit may be a resonant motor having, specifically, a movable motor section spring-mounted to the handle section and a stator section fixedly mounted to or to the housing of the handle section. The movable motor section may be spring-mounted by at least one mounting spring. The spring-mounted movable motor section can be understood as a spring-mass system having a resonant frequency. The drive frequency may be selected to match or be close to the resonant frequency. The resonant frequency is understood here as the resonant frequency under normal use conditions of the personal care device, i.e., typically, at least a portion of the mass of the head section is a portion of the movable mass of the movable motor section. In other words, the resonant frequency is related to the current mounting condition of the head section. The drive frequency used by the controller to apply a periodic drive signal may be fixed or, in some examples, may be adaptable, for example, so that the resonant frequency may depend on the force applied to the head section, or so that the resonant frequency may change over time due to wear of the head section and / or aging of the drive unit.

[0019] The controller may be configured and / or arranged to perform specific steps depending on the determination of the mounting status, the type of head unit mounted, and / or the wear condition of the head unit. For example, if the controller detects that the head unit is not mounted, it may change the weighting coefficient from the standard operating value to a predetermined first value, particularly lower than the standard operating value, in order to avoid noise and vibration caused by the handle. In particular, when the head unit is not mounted, noise and vibration may occur because the drive frequency and resonant frequency do not match. Generally, reducing the amplitude of motion may be considered a common improvement when the head unit is missing. The controller may be configured and / or arranged to perform additional or alternative steps depending on the determination of whether or not the head unit is mounted. For example, the control unit may trigger an indicator element to indicate the mounting status, and / or the controller may prevent the relevant time counter from operating to determine the usage time of the head unit when the head unit is not actually mounted. In general, it should be understood that the determination of the mounting status, the type of head unit mounted, and / or the wear condition of the head unit mounted may result in one or more action steps performed by the personal care device. Indication of the determined mounting state, head type, and / or wear state via one or more indicator elements may be one of these operational steps.

[0020] Once a specific type of head unit to be attached to the handle unit is determined, the controller may adapt at least one parameter that characterizes the drive function. Such a parameter may be a weighting coefficient, the specific shape of the drive function, or the drive frequency. Furthermore, if the resonant frequency changes depending on the type of head unit to be attached, the drive frequency may be adapted so that it is the same as the resonant frequency, or so that a predetermined distance is maintained between the drive frequency and the resonant frequency.

[0021] The controller may be configured and / or arranged to trigger an indication of a determined mounting state, a determined type of mounted head, and / or a determined wear state of the mounted head. For each of these indication tasks, a visual indicator, such as one or more LEDs provided on the personal care device, or a display provided on the personal care device may be used. In some examples, the indication means may be implemented by a device separate from the personal care device, such as a display device, such as a mobile phone, tablet, laptop computer, or dedicated display device. This does not preclude the fact that, alternatively or additionally, the above determinations may be indicated tactilely by a tactile or tactile indicator, such as a vibrator, and / or an acoustic indicator such as a loudspeaker or buzzer.

[0022] The controller may be configured and / or positioned to determine the phase shift value at a predetermined position within at least one half-cycle of the periodic drive signal. No position should be ruled out, but the measurement position may be selected to be approximately one-quarter of the way through each half-cycle, i.e., the phase shift value may be measured when approximately one-quarter of the duration of each half-cycle has elapsed, resulting in a duration of three-quarters of the half-cycle. Alternatively or additionally, the phase shift value may be determined at approximately three-quarters of the duration of each half-cycle.

[0023] Figure 1 is a schematic diagram of an exemplary personal care device 1 implemented as an electric toothbrush. The personal care device 1 comprises a head 10 and a handle 20, the head 10 being detachably attached to the handle 20. The head 10 may be detachable from the handle 20 at any time, for example, even while the personal care device 1 is in operation. If the head 10 is detached in operation, this may cause problems for the user, as the moving elements of the handle 20 may injure the user or at least cause irritation to the user. Even if the potential injury is essentially negligible, such as a slight pinch of skin, such an event may reduce the appeal of the personal care device and should preferably be avoided. As will be described in more detail below, the personal care device 1 according to this disclosure is configured and / or arranged to determine the mounting state of the head 10 by analyzing a periodic motor response signal from a motor located in the handle 20, specifically by analyzing one or more phase shift values ​​between a periodic drive signal and a periodic motor response signal provided in the motor. When it is detected that the head unit 10 has been removed from the handle unit 20, the controller reduces the energy supplied to the motor so that the motor moves the drive shaft with a reduced amplitude or frequency, thereby reducing the aforementioned risk of, for example, pinching the skin. The personal care device 1 may also include a first indicator 22 for indicating the attachment status of the head unit 10, which may be implemented as an optical indicator such as an LED that can be switched on or off, or by changing color, or by flashing, etc., to indicate that the head unit 10 is not attached to the handle unit 20. Further indicators such as a second indicator 23 and potentially a third indicator 24 may also be provided, for example, to indicate the type of head unit 10 attached to the handle unit and / or the wear condition of the attached head unit 10.One or all of the indicators 22, 23, and 24 may be visual indicators, but at least one of the indicators 22, 23, or 24 may be implemented as a tactile / tactile or audible indicator, as already stated.

[0024] The head unit 10, implemented here as an example of a brush head for an electric toothbrush, comprises a head 11 positioned to be driven to vibrate rotation M1 around a rotation axis R relative to the housing 12 of the head unit 10. The housing 12 of the head unit 10 is detachably mounted to the housing 21 of the handle unit 20 and remains fixed and connected during operation so that only the head 11 moves relative to the housing 21 of the handle unit 20 when driven. In at least one other exemplary embodiment, the entire head unit may be driven and moved. The head 11 here comprises a carrier 110 and a plurality of personal care elements 111, which are implemented in this example as brush filaments or filament tufts as known in the art of toothbrushes. Other personal care elements, such as elastomer elements, may be used additionally or alternatively. The head unit 10 may receive motion from the handle unit 20 by being coupled, for example, to a drive shaft coupled to a motor, and may include a motion transmission unit for transmitting this motion to the movable head 11.

[0025] Figure 2 is a schematic diagram of the components of a personal care device described exemplary in relation to Figure 1. The exemplary personal care device may comprise an energy source 30, a controller 40, and a motor 50 coupled to a drive shaft 51 to which a first type of head unit 200 is mounted in Figure 2. A second type of head unit 210 is shown in an unmounted state to show that the kit according to this disclosure may be formed by a single handle unit and two or more head units 200, 210. The first type of head unit 200 and the second type of head unit 210 each comprise a head 201 and 211 and a housing 202 and 212, respectively. During operation, a force F can act on the head 201 of the mounted head unit 200, which loads the motor 50 and consequently results in a reduction of the output amplitude delivered by the drive shaft 51 of the motor 50, typically. The goal of motor control is to maintain the motion amplitude provided by the drive shaft 51, and consequently, a weighting coefficient can be used to increase or decrease the energy delivered to the motor 50.

[0026] The controller 40 is connected to the energy source 30 to receive energy to supply power to the controller 40. Furthermore, the controller 40 may supply energy from the energy source to the motor 50 in order to drive the motor 50. Figure 2 shows the drive voltage V d It is indicated that the motor 50 is supplied with a drive voltage V. d This may be a periodic drive signal. Voltage V dThe current may be provided by a voltage shaping circuit, or the controller 40 may be configured to apply pulse-width modulated (PWM) voltage pulses, as is commonly known in the art. Thus, the resulting current flowing through the motor 50 can be shaped to have an essentially sinusoidal shape. The number of voltage pulses per period of the periodic drive signal may be 8 or more, 32 or more, 128 or more, or 256 or more. The width of each pulse provided in the motor 50 each period (in other words, the on-time of the voltage pulse during its time period) may be a preset value stored in the memory 41 of the controller 40. The preset value may be given as a digital number having a resolution of, for example, 4 bits, 6 bits, 8 bits, 10 bits, 12 bits, 16 bits, 20 bits, 24 bits, or any other perceptible resolution.

[0027] Pre-set values ​​may be provided for a specific standard height of the PWM shaping signal. Since the energy required by the motor 50 typically depends on the load on the motor 50, the controller 40 can apply weighting factors to all pre-set values ​​to apply reduced or increased energy levels to the motor 50. As just one example, a manufacturer may set the pre-set values ​​so that 50% of the maximum peak height of the average voltage signal is achieved under no-load conditions. If more energy is required by the motor 50, the controller 50 may increase the weighting factors for all pre-set values ​​to achieve voltage peak values ​​such as 60% or 72.3%. In this example, since 50% was the pre-set standard value, a weighting factor of 1.2 would need to be applied to achieve 60%, and a weighting factor of 1.446 would need to be applied to achieve 72.3%. As will be described in more detail below, the controller 40 may be configured to reduce the energy applied to the motor 50 under certain conditions, for example, when the controller 40 detects that the head unit 200 has been detached from the handle unit. The reduced peak value may be as low as 20%, and for example, a weighting coefficient of 0.4 for each value is applied to the preset value relative to a standard value of 50%.

[0028] According to the present disclosure, the controller 40 is configured to process the periodic motor response signal V r , for example, may be arranged to sample the current flowing through the motor 50, or a voltage induced by a moving motor part within a stationary motor part of the motor 50 such as back-electromotive force (B-EMF), or a voltage induced by the moving motor part, in a separate sensor device such as a separate coil. The periodic motor response signal V r is typically phase-shifted relative to the periodic driving voltage V d , and the phase shift value is indicated by T ph . It is known that when the attachment state of the head portion 200 on the handle portion changes, the phase shift value T between the periodic motor response signal V r and the periodic driving signal V d changes deterministically (see FIG. 4 and the respective descriptions further below). The phase shift value T ph changes deterministically for different types of head portions, and even for different wear states of the head portion, although the change is typically not very large. In FIG. 3A, it is shown that two different head portions may result in two different motor response functions V ph and V' r respectively having different phase shift values T r and T' ph ph .

[0029] Since the phase shift value T ph does not change very greatly for different types of head portions or along with changes in wear state, the phase shift value T ph may be collected over time to average measurement values, and preferably to determine the phase shift value T ph for different weighting coefficients. The latter is further described below with reference to FIG. 5.

[0030] As already described, FIG. 3A shows the periodic driving signal V over time t d and the voltage V of the periodic motor response signal V r ​​m This is a schematic diagram of V. d and V r Phase shift value T between ph This is shown. Periodic drive signal V d It should be understood that the point at which it reaches its maximum value is known by definition. Also, the periodic motor response signal V r It should be understood that the measurement does not need to be taken over the entire period; for example, it may suffice to measure only the portion where a peak is expected. Instead of determining the temporal distance between peak signals, the phase shift value is determined by the periodic drive voltage V d A given time t within the period m It can also be determined by measuring the periodic motor response signal V. d The measurement time t m The voltage value V1 is present in the shifted periodic motor response signal V'. r The measurement time t m It is shown that the measured voltage value V2 is present. After calibration, the controller 40 sets the phase shift value T' based on the voltage value V2. ph It becomes possible to make a decision. Measurement time t m is a periodic drive signal V d It was found that good results could be achieved when the period was located at approximately 1 / 4 or 3 / 4 of the half-cycle.

[0031] Figure 3B shows the periodic drive signal V applied to the motor under three different weighting coefficients: WF=40%, WF=60%, and WF=80%. dThis is schematically shown. Here, we assume that the drive frequency is constant. It should be understood that in some embodiments, the drive frequency may be adapted, for example, depending on the load on the head unit or the type of head unit. Three different curves of the periodic drive signal are shown for three different weighting coefficients WF, namely WF=80%, WF=60%, and WF=40%. The periodic drive signal is used to provide the required energy to the motor. This means that if the periodic drive signal has a higher peak voltage with the same shape in other respects, i.e., if the periodic drive signal is increased by the weighting coefficient WF, more energy is delivered to the motor. The periodic drive signal of the motor under conditions where the drive head unit of the personal care device is unloaded may be the periodic drive signal shown for WF=40%. Depending on the load, for example, to maintain the motor amplitude under different loads, the weighting coefficient may be increased and continuously decreased when the load decreases again.

[0032] Figure 4 shows the phase shift value V between the periodic drive signal and the periodic motor response signal. ph This is a graph of the time-series measurement curve 410 (measured in millivolts). An Oral-B iO toothbrush was used as a personal care device. During the measurement period, the head was repeatedly manually removed from the handle. Periods without the head are identified by having a phase shift value of approximately -20mV (absolute voltage value is arbitrary). Phase shift value V during periods with the attached head. phThis depends on the load condition of the head. To distinguish between the head being detached and the head being attached, a threshold phase shift value of, for example, TR = -10mV can be applied. As described, the controller may be configured to determine whether the head is attached or not, and may (a) indicate that the head is detached, and / or (b) reduce the weighting coefficient WF to a lower value, for example, a value in the range of 1% to 35%, such as 5%, 10%, 15%, 20%, or any other value. Reducing the overall weighting coefficient leads, among other things, to a reduction in the amplitude of the drive shaft to which the head is coupled, and a reduction in the noise of the handle. When the head is reattached to the handle, the controller may be configured to reset the weighting coefficient back to the no-load starting value, for example, WF = 40%. Instead of switching the weighting coefficient in one step, the controller may be configured to slide the weighting coefficient from the value applied when the head is not attached to the unloaded weighting coefficient, for example, within a specific time frame, e.g., a 1-second window, or e.g., a 5-second time frame, changing the value linearly from 5% to 40%. Alternatively, instead of switching the weighting coefficient instantaneously, the controller may be configured to introduce a delay period between the time the head attachment is determined and the weighting coefficient is switched. This may allow the user to release their fingers from the head before the head is driven at its normal speed.

[0033] Figure 5 shows the phase shift value V, which depends on the weighting coefficient WF given as a percentage. ph This figure shows three measurement curves 510, 520, and 530 (given in arbitrary units). The three different curves 510, 520, and 530 relate to different types of head parts; for example, the personal care device may be an electric toothbrush, and the three different head parts may be three different brush heads, for example, a standard cleaning head, a high-sensitivity cleaning head, and an interdental cleaning head. Phase shift value V phA single measurement may not be reliable enough to distinguish between the various heads that can be attached to the handle, but this distinction may be possible if the phase shift value curve is determined according to a weighting factor WF. The controller may be configured to compare the acquired phase shift value of the attached head with a reference set of one, two, three, or more stored phase shift values ​​in order to determine the type of attached head. Once the type of head has been determined, the controller may be configured to indicate the type of attached head.

[0034] Similar to the above description relating to Figure 5, the wear condition of the mounted head can be determined. Each reference curve or reference set of phase shift values, which depend on a weighting coefficient, may be stored. The controller may then be configured to compare the currently determined set of phase shift values ​​with one or more of the reference curves or reference sets of phase shift values ​​in order to determine the wear condition of the mounted head. The controller may be further configured to indicate the determined wear condition, or to indicate when the wear condition exceeds a predetermined wear threshold that makes it desirable to replace the head with a new one.

[0035] The dimensions and values ​​disclosed herein should not be understood as being strictly limited to the exact numerical values ​​listed. Instead, unless otherwise specified, each such dimension is intended to mean both the listed value and the functionally equivalent range encompassing that value. For example, a dimension disclosed as "40 mm" is intended to mean "approximately 40 mm."

Claims

1. It is a personal care device, A handle portion that allows the user to grasp the personal care device with their hand, A head unit for providing personal care treatment in a personal care area, the head unit being detachably attached to the handle unit, A drive unit comprising a motor for driving and moving at least a portion of the head portion, It is a controller, A periodic drive signal is provided to the motor. Determine at least one phase shift value between the periodic drive signal and the periodic motor response signal. Based on the determined phase shift value, Whether or not the head portion is attached to the handle portion, and / or, The type of head portion attached to the handle portion, and / or, A personal care device comprising a controller arranged and / or configured for determining the wear condition of the head portion attached to the handle portion.

2. The aforementioned periodic motor response signal is as follows: The current flowing through the motor, or The voltage across both ends of the motor, or The voltage between the motor terminal and the reference voltage, or The personal care device according to claim 1, wherein the signal is at least one of signals induced by at least a portion of the motor in the sensor, preferably the motor comprises a magnet fixed to the movable part of the motor, and the sensor comprises a coil.

3. The personal care device according to claim 1 or 2, wherein the controller is configured and / or arranged to provide the periodic drive signal as a pulse width modulated signal.

4. The personal care device according to any one of claims 1 to 3, wherein the periodic drive function is adaptable by a controllable weighting coefficient, the weighting coefficient being dynamically set by the controller to maintain at least substantially the amplitude of the motion of at least a portion of the head that is driven to move.

5. The personal care device according to claim 4, wherein the controller is configured and / or arranged to determine a plurality of phase shift values ​​depending on the weighting coefficient.

6. The controller is configured and / or arranged to determine the mounting state of the head portion, the type of the head portion attached to the handle portion, or the wear state of the head portion attached to the handle portion by comparing the at least one determined phase shift value with at least one reference phase shift value or a predetermined threshold, wherein the determined phase shift value is calculated by averaging or considering a plurality of phase shift values, according to any one of claims 1 to 5.

7. The personal care device according to any one of claims 1 to 6, wherein the motor of the drive unit is a resonant motor comprising a spring-mounted armature and a stator, the spring-mounted armature has a resonant frequency, and the drive frequency is essentially the same as the resonant frequency.

8. The personal care device according to any one of claims 1 to 7, wherein the controller is configured and / or arranged to reduce the weighting coefficient to a predetermined first value when the controller determines that the head portion is not attached to the handle portion.

9. The personal care device according to claim 8, wherein the controller is configured and / or arranged to indicate the mounting state of the head portion by an indicator, preferably a visual indicator.

10. The personal care device according to any one of claims 1 to 9, wherein the controller is configured and / or arranged to adapt at least one parameter characterizing the periodic drive signal depending on the determined type of the head portion attached to the handle portion.

11. The personal care device according to any one of claims 1 to 10, wherein the controller is configured and / or positioned to indicate the determined wear state of the head portion attached to the handle portion, preferably the wear state is indicated by an optical indicator.

12. The personal care device according to any one of claims 1 to 11, wherein the controller is configured and / or positioned to indicate the determined type of the head portion, preferably the determined type of the head portion is indicated by an optical indicator.

13. The personal care device according to any one of claims 1 to 12, wherein the phase shift value is determined at a predetermined position within the period of the periodic drive signal, and preferably, the phase shift value is determined at about one-quarter of the half-period of the periodic drive signal.

14. The personal care device according to any one of claims 1 to 13, wherein the periodic drive signal is essentially a sinusoidal drive signal.

15. The personal care device according to any one of claims 1 to 14, wherein the controller is configured and / or arranged to determine the phase shift value in response to a user-operable trigger signal.

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