GB2617152A

GB2617152A - Haircare appliance

Info

Publication number: GB2617152A
Application number: GB2204624.7A
Authority: GB
Inventors: John Brown Benjamin; David Nicolaou Richard; James Forster Benjamin
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2023-10-04
Also published as: WO2023187330A1; GB202204624D0

Abstract

A haircare appliance comprises a barrel 15 around which hair may be wrapped, a heating element (17, fig. 2) for heating the barrel, a sensor (19, fig. 2) for sensing a parameter indicative of the presence or absence of hair in contact with the barrel, and a controller (33, fig.3). The controller is configured to determine the presence or absence of hair in contact with the barrel based on data output by the sensor and control a supply of electrical power to the heating element based on the determination. The barrel may comprise a plurality of zones 21 arranged longitudinally and/or circumferentially around the barrel. The controller may supply power only to those zones for which the presence of hair is determined. The temperature of the heating elements may be maintained at a setpoint, and the setpoint may be increased for those zones where the presence of hair is determined.

Description

HAIRCARE APPLIANCE

The present invention relates to a haircare appliance A haircare appliance may utilise a barrel to style the hair of a user. In use, a tress of hair may be wrapped around the barrel and the barrel heated to produce a style in the tress. This process may then be repeated to style a full head of hair.

The present invention provides a haircare appliance comprising: a barrel around which hair may be wrapped; a heating element for heating the barrel; a sensor for sensing a parameter indicative of a presence or absence of hair in contact with the barrel; and a controller configured to: determine the presence or absence of hair in contact with the barrel based on data output by the sensor; and control a supply of electrical power to the heating element based on the determination. As a result, the functionality of the haircare appliance may be improved as the temperature of the heating element may be changed depending on whether or not hair is present or absent (i.e. changed depending on whether or not heating is required for styling). For example, the temperature of the heating element may be increased when hair is present and decreased when hair is absent.

The haircare appliance may comprise a further sensor for sensing a temperature of at least one of the barrel or heating element. In examples, the sensor and further sensor may comprise different types of sensors. For example, the sensor for sensing the parameter indicative of the presence or absence of hair may sense a parameter other than temperature. In some examples, the outputs of the sensor and the further sensor could be combined to make a more robust determination of the presence or absence of hair.

The controller may be configured to increase the supply of electrical power to the heating element to increase the temperature of the heating element in response to determining the presence of hair in contact with the barrel or to decrease the supply of electrical power to the heating element to decrease the temperature of the heating element in response to determining the absence of hair in contact with the barrel. This may result in several benefits. Firstly, this may improve the energy efficiency of the haircare appliance. In haircare appliances that are battery powered, this may result in increased run times whilst also maintaining performance. In contrast, known battery powered haircare appliances may achieve increased run times by reducing performance, for example by reducing the heating element temperature or reducing the barrel size, which may limit styling options. Secondly, this may increase the operational life of the haircare appliance by reducing the amount of time the heating element is required to operate at the higher temperature required for hair styling. Thirdly, the safety of the haircare appliance may be improved as the temperature of the heating element may be reduced when not in use, i.e. when hair is not in contact with the barrel.

The controller may be configured to control the supply of electrical power to the heating element to maintain the temperature of the heating element at a setpoint and increase the setpoint in response to determining the presence of hair in contact with the barrel or decrease the setpoint in response to determining the absence of hair in contact with the barrel. By increasing or decreasing the setpoint in response to determining the presence or absence of hair, the heating element may operate at a lower temperature when hair is absent to thereby reduce energy consumption and thus improve the energy efficiency and longevity of the haircare appliance.

The controller may be configured to increase the setpoint from a first value to a second value in response to determining the presence of hair in contact with the barrel and decrease the setpoint from the second value to the first value in response to determining the absence of hair in contact with the barrel. Thereby, the haircare appliance may respond to the arrival of hair by operating at a higher setpoint temperature (second value) to style the hair and respond to the subsequent departure of the hair by operating at a lower setpoint temperature (first value) to reduce the energy consumption of the haircare appliance.

The barrel may comprise a plurality of zones. The haircare appliance may comprise a plurality of heating elements and a plurality of sensors. Each heating element may be for heating a respective zone of the barrel and each sensor may be for sensing a parameter indicative of the presence or absence of hair in contact with a respective zone of the barrel.

The controller may be configured to determine the presence or absence of hair in contact with each of the zones of the barrel based on data output by the sensors and control a supply of electrical power to each of the heating elements based on the determination. As a result, the haircare appliance may be able to respond to uneven distributions of hair over the barrel. For example, the haircare appliance may respond differently in zones where hair is present compared to zones where hair is absent In response to determining the presence of hair in contact with one or more of the zones of the barrel, the controller may be configured to increase the supply of electrical power to only those heating elements of the zones for which the presence of hair is determined.

As a result, the energy consumption of the haircare appliance may be reduced without adversely impacting heating of the hair.

The controller may be configured to control the supply of electrical power to each of the heating elements to maintain the temperature of each of the heating elements at a respective setpoint and increase the setpoint for only those heating elements of the zones for which the presence of hair is determined. As a result, the temperature of only those zones in contact with hair is increased Those zones that are not in contact with hair may operate at a lower temperature to thereby reduce energy consumption and improve the efficiency and longevity of the haircare appliance.

For only those heating elements of the zones for which the presence of hair is determined, the controller may be configured to increase the setpoint from a first value to a second value and decrease the setpoint from the second value to the first value for only those heating elements of the zones for which the subsequent absence of hair is determined. Thereby, the haircare appliance may respond to the arrival of hair on a zone by operating the heating element for that zone at a higher temperature and respond to the subsequent departure of the hair from the zone by operating the heating element for that zone at a lower temperature. As a result, the energy consumption of the haircare appliance may be reduced without adversely affecting heating and styling of the hair.

The plurality of zones may comprise zones arranged longitudinally along a length of the barrel. When a user wraps a tress of hair around the barrel, the hair may not be wrapped along the full length of the barrel. For example, a tress of hair may be wrapped around the middle portion of the barrel or towards one end of the barrel. By comprising zones arranged longitudinally along the length of the barrel, the power supplied to the heating elements of those zones not in contact with the hair may be reduced. As a result, the energy consumption of the haircare appliance may be further reduced without adversely affecting heating and styling of the hair.

The plurality of zones may comprise zones arranged circumferentially around the barrel.

Hair wrapped around the barrel may not extend around the entirety of the barrel. For example, when a user wraps a tress of hair around the barrel, there may be longitudinal gaps between adjacent turns of the hair. By arranging zones circumferentially around the barrel, the power supplied to the heating elements of those zones located at gaps in the hair may be reduced. As a result, the energy consumption of the haircare appliance may be further reduced without adversely affecting heating and styling of the hair.

The barrel may comprise no less than 3 zones. As the number of zones decreases, the areal granularity with which the controller can control the heating of the barrel also decreases.

Accordingly, the energy consumption of the haircare appliance is likely to increase Therefore, by having no less than 3 zones, the controller may achieve good areal granularity of control and thereby reduce the energy consumption of the haircare appliance.

The barrel may comprise no more than 24 zones. As the number of zones increases, the number of associated sensors and heating elements also increases. This is likely to increases the cost and complexity of the haircare appliance. Additionally, as the number of zones increases excessively, say beyond 24 zones, only relatively modest additional reductions in energy consumption are likely to occur. By comprising no more than 24 zones, the cost and complexity of the haircare appliance may thereby be reduced whilst also achieving a good level of energy consumption reduction. Furthermore, providing a barrel comprising no less than 3 zones and no more than 24 zones may provide a good balance between the competing needs of reducing the energy consumption, and reducing the cost and complexity of the haircare appliance.

The barrel may have a wall thickness of no greater than 0.5 mm. As a result, a low heat capacity per unit area may be achieved for the barrel. Thereby the haircare appliance may be more responsive to heating demands. For example, the barrel may be more quickly heated to an operating temperature, and/or respond more quickly to temperature changes during use, e.g. as hair is brought into contact with and then subsequently removed from the barrel. Additionally, a relatively thin wall thickness may reduce lateral heat conduction and thereby reduce the heat transferred from a zone that is being heated to adjacent zones which may not be being heated (e.g. due to no hair being in contact with those zones). This may further reduce the energy consumption of the haircare appliance.

The barrel may have a wall thickness of no less than 0.05 mm. As a result, the robustness of the barrel may be improved. Furthermore, providing a barrel with a wall thickness of no greater than 0.5 mm and no less than 0.05 mm may provide a good balance between the competing needs of improving the responsiveness of the haircare appliance and improving the robustness of the barrel. The barrel may be formed of material having a relatively high thermal conductivity, such as a metal, metal alloy or ceramic. As a result, a low heat capacity per unit area may be achieved for the barrel which may improve the responsiveness of the haircare appliance.

The haircare appliance may comprise a support located inside of the barrel and having a wall thickness greater than a wall thickness of the barrel. As discussed previously, the barrel may be relatively thin and therefore may be easily deformed. By comprising the support, the haircare appliance may be provided with a means of structurally supporting the barrel.

Thereby the haircare appliance may be able to comprise the relatively thin barrel to improve responsiveness whilst also reduce deformations in the barrel to a good level. The support may be formed of a thermally insulating material. Thereby, the support may reduce the amount of heat transferred inwards from the heating element and thereby increase the amount of heat transferred from the heating element to the barrel. The support may have a wall thickness of no less than 0.5 mm. As a result, deformations to the barrel may be reduced to a good level. The support may comprise at least one of ribbing, cross-hatching and support cross beams. Thereby, deformations to the barrel may be further reduced.

The heating element may be attached directly to the barrel. As a result, the amount of thermal insulation that may be provided between the heating element and the barrel, e.g. due to an airgap or other components being located between the heating element and the barrel, may be reduced. The responsiveness of the haircare appliance may thereby be improved.

The heating element many comprise a resistive film heater. This may enable a relatively low heat capacity to be achieved for the heating element which may improve the responsiveness of the haircare appliance. Moreover, resistive film heaters may be more easily designed and manufactured to conform to the shape of the barrel. Thereby the heating element may be designed to provide relatively evenly distributed heating. This may reduce potential damage to hair that might arise due to local hot spots.

The present invention also provides a method comprising sensing a parameter indicative of a presence or absence of hair in contact with a barrel of a haircare appliance, determining the presence or absence of hair in contact with the barrel based on the sensed property, and controlling a supply of electrical power to a heating element of the haircare appliance based on the determination.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of a haircare appliance; Figure 2 is a cross-sectional view of a portion of a barrel assembly of the haircare appliance; Figure 3 is a block diagram of electrical components of the haircare appliance; Figure 4 is a flowchart showing an example of how a controller of the haircare appliance controls a heating element of the barrel assembly; Figure 5 illustrates the behaviour of a setpoint value when employing the flowchart of Figure 4; and Figure 6 shows an example method which may be implemented by the haircare appliance.

DETAILED DESCRIPTION OF THE INVENTION

The haircare appliance 10 of Figures 1 to 3 comprises a barrel assembly 11 and a handle assembly 13 The barrel assembly 11 comprises a barrel 15, a plurality of heating elements 17, a plurality of sensors 19, and a support 20.

The barrel 15 is formed of a metal, such as aluminium, and has a hollow cylindrical shape. The barrel 15 comprises a plurality of zones 21. Specifically, in this example, the barrel 15 comprises 12 zones 21. The zones 21 are arranged longitudinally along a length of the barrel 15 and circumferentially around the barrel 15.

The heating elements 17 are located inside of the barrel 15. Specifically, each heating element 17 is located underneath a respective zone 21 of the barrel 15 such that each zone 21 may be heated by a respective heating element 17. In this example, the heating elements 17 are in direct thermal contact with the barrel 15 (i.e. no other component of the haircare appliance 10 is located between the heating elements 17 and the barrel 15, and there is no airgap between the heating elements 17 and the barrel 15). As a result, a relatively good thermal response may be achieved. However, other examples are envisaged in which the heating elements 17 are not in direct thermal contact with the barrel 15.

The sensors 19 are also located inside the barrel 15. Each sensor 19 senses a parameter indicative of a presence or absence of hair in contact with a respective zone 21 of the barrel 15. In this example, each sensor 19 is mounted to the heating element 17 which heats a respective zone 21 and comprises a temperature sensor for sensing the temperature of a respective heating element 17. Thereby, in this example, the parameter is a temperature of each heating element 17. Equally, other types of sensors may be used, and the sensors 19 need not be mounted to a respective heating element 17. For example, the sensors 19 may comprise optical, strain or capacitive sensors. In some examples, multiple sensors of different types may be used. The outputs of the multiple sensors may be combined to make a more robust determination of the presence or absence of hair.

The support 20 has a similar shape to the barrel 15 but is smaller such that the support 20 fits inside of the barrel. The support 20 provides structural support to the other components of the barrel assembly 11, which (as will be discussed below) may be relatively thin and therefore easily deformed. The support 20 is formed of a thermally insulating material. Thereby, the support 20 reduces the amount of heat transferred inwards from the heating elements 17 and thereby increases the amount of heat transferred from the heating elements 17 to the barrel 15.

The handle assembly 13 comprises a handle 23, a power supply 25 and control unit 27.

The handle 23 is connected at one end to the barrel assembly 11 arid has a hollow cylindrical shape.

The power supply 25 is housed within the handle 23 and supplies electrical power to electrical components of the haircare appliance 10, such as the heating elements 17, the sensors 19 and the control unit 27. In this example, the power supply 25 comprises a battery supplying a DC voltage. In other examples, electrical power may be provided by a mains power supply, arid the power supply 25 may comprise a rectifier and a DC-to-DC converter that outputs a DC voltage.

The control unit 27 is housed within the handle 23 and comprises multiple switches 29, a user interface 31 and a controller 33.

Each of the switches 29 is connected between the power supply 25 and a respective one of the heating elements 17 Accordingly, when one of the switches 29 is closed, electrical power is supplied to the respective heating element 17 and the temperature of the heating element 17 increases. Conversely, when the switch 29 is opened, electrical power supplied to the heating element 17 is halted and the temperature of the heating element 17 decreases. Accordingly, the switches 29 may be controlled in order to control the temperature of the heating elements 17, and thereby the temperature of the respective zone 21.

The user interface 31 may be used to power on and off the haircare appliance 10. Additionally, the user interface 31 may also be used to select a particular heat setting (e.g., low, medium, high).

The controller 33 is connected to the switches 29 and the user interface 31. Additionally, the controller 33 is connected to each of the sensors 19. As a result, the controller 33 is provided with data representing a measure of the parameter indicative of the presence or absence of hair in contact with each zone 21. The controller 33 is responsible for controlling the operation of the haircare appliance 10. In particular, the controller 33 controls the opening and closing of the switches 29, arid thus the electrical power supplied to the heating elements 17, in response to data received from the user interface 31 and the sensors 19. For example, the controller 33 may control the switches 29 such that the temperature of each of the heating elements 17 is maintained at a particular setpoint. The setpoint may then be defined by a heating setting selected by a user using the user interface 31. In examples, the controller 33 may control the switches 29 using closed loop control, such as PI or PTID control, in order to maintain the temperature of the heating elements 17 at the setpoint.

In use, the user grips the handle 23 and wraps hair around the barrel 15. Each sensor 19 then outputs data to the controller 33 that is indicative of the presence or absence of hair in contact with each respective zone 21. In this example, each sensor 19 is a temperature sensor and outputs data that is indicative of the temperature of the respective heating element 17 of each zone 21. As explained below, the temperature of the heating element 17 can then be used to determine whether hair is present or absent on the respective zone 21.

The controller 33 then determines the presence or absence of hair in contact with each zone 21 based on the data output by each of the sensors 19. Specifically, in this example, the controller 33 compares the sensed temperature against a threshold or a setpoint and determines the presence or absence of hair in contact with each zone 21 based on the comparison. The presence of hair typically lowers the temperature of the heating element 17 of a respective zone 21 for a given electrical input power. Conversely, when hair is removed from a zone 21, the temperature of the heating element 17 will increase, again for a given electrical input power. This behaviour can therefore be used to determine the presence or absence of hair by comparing the sensed temperature against a threshold or a setpoint. For example, if the sensed temperature drops below a threshold, or if the difference between the sensed temperature and a desired setpoint is excessive (e.g., the sensed temperature is well below the setpoint), this may suggest that hair is present. Conversely, if the sensed temperature rises above a threshold, or if the difference between the sensed temperature and a desired setpoint is excessive (e.g., if the sensed temperature is well above the setpoint), this may suggest that hair is no longer present.

The controller 33 then controls the supply of electrical power to each of the heating elements 17 based on the determination of the presence or absence of hair in contact with each zone 21. Specifically, the controller 33 opens and closes the switches 29 as described above. As a result, the functionality of the haircare appliance 10 may be improved as the temperature of each heating element 17 may be changed depending on whether or not hair is present or absent (i.e. changed depending on whether or not heating is required). For example, the temperature of each heating element 17 may be increased when hair is present and decreased when hair is absent. This may result in several benefits. Firstly, this may improve the energy efficiency of the haircare appliance 10. In haircare appliances that are battery powered, this may result in increased run times without sacrificing performance. In contrast, known battery powered haircare appliances may achieve increased run times by reducing performance. For example, longer run times may be achieved by reducing the temperature of the heating elements or by reducing the size of the barrel, which may limit styling options or result in unsatisfactory styling results. Secondly, this may increase the operational life of the haircare appliance 10 by reducing the amount of time that each heating element 17 is required to operate at the higher temperature. Thirdly, the safety of the haircare appliance 10 may be improved as the temperature of the heating elements 17 may be reduced when not in use, i.e. when hair is not in contact with a respective zone 21.

The construction of the barrel 15 will now be discussed in more detail In the above example, the barrel 15 comprises 12 zones 21. In other examples, the barrel 15 may comprise a different number of zones 21. Indeed, the barrel 15 may comprise a single zone only. However, there are advantages in having multiple zones. For example, the haircare appliance 10 is better able to respond to uneven distributions of hair over the barrel 15. In particular, the haircare appliance 10 may respond differently in zones where hair is present compared to zones where hair is absent.

As the number of zones 21 increases, the areal granularity with which the controller 33 can control the heating of the barrel 15 also increases. Accordingly, the energy consumption of the haircare appliance 10 is likely to decrease. However, as the number of zones 21 increases the number of associated sensors 19 and heating elements 17 also increases. This is likely to increases the cost and complexity of the haircare appliance 10. Additionally, as the number of zones 21 increases, additional reductions in energy consumption are likely to be more modest. Therefore, providing a barrel 15 comprising no less than 3 zones 21 and no more than 24 zones 21 may provide a good balance between the competing needs of reducing the energy consumption, and reducing the cost and complexity of the haircare appliance 10.

The zones 21 are arranged longitudinally along the length of the barrel 15. That is to say that adjacent zones 21 are offset in a longitudinal direction from one another. When a user wraps a tress of hair around the barrel 15, the hair may not be wrapped along the full length of the barrel 15. For example, a tress of hair may be wrapped around the middle portion of the barrel 15 or towards one end of the barrel 15. By comprising zones 21 arranged longitudinally along the length of the barrel 15, the power supplied to the heating elements 17 of those zones for which hair is absent may be reduced. As a result, the energy consumption of the haircare appliance 10 may be further reduced without adversely affecting heating and styling of the hair. However, examples are envisaged where the zones 21 are not arranged longitudinally, e.g., the barrel 15 comprises only a single zone or the zones are only arranged circumferentially.

Additionally, the zones 21 are arranged circumferentially around the barrel 15. That is to say that adjacent zones 21 are additionally offset in a circumferential direction from one another. Hair wrapped around the barrel 15 may not extend around the entirety of the barrel 15. For example, when a user wraps a tress of hair around the barrel 15, there may be longitudinal gaps between adjacent turns of the hair. By arranging zones circumferentially around the barrel 15, the power supplied to the heating elements 17 of those zones 21 located at gaps in the hair may be reduced. As a result, the energy consumption of the haircare appliance 10 may be further reduced without adversely affecting heating and styling of the hair. However, examples are envisaged where the zones 21 are not arranged circumferentially, i.e. the barrel 15 comprises only a single zone or the zones are only arranged longitudinally.

The barrel 15 has a wall thickness of 0.4 mm. Equally, other wall thicknesses may be used.

As the wall thickness decreases, a lower heat capacity per unit area may be achieved for the barrel 15. Thereby the haircare appliance 10 may be more responsive to heating demands. For example, the barrel 15 may be more quickly heated to an operating temperature, and/or respond more quickly to temperature changes during use, e.g. as hair is brought into contact with and then subsequently removed from the barrel 15. Additionally, a relatively thin wall thickness may reduce lateral heat conduction and thereby reduce the heat transferred from a zone that is being heated to adjacent zones which are not being heated (e.g. due to the absence of hair). This may further reduce the energy consumption of the haircare appliance 10. However, as the wall thickness decreases, the robustness of the barrel 15 may also decrease. Therefore, providing a barrel 15 with a wall thickness of no greater than 0.5 mm and no less than 0.05 mm may provide a good balance between the competing needs of thermal responsiveness and robustness.

The support 20 has a wall thickness of 1.0 mm. Equally, other values for the wall thickness of the support 20 may be used. However, as the wall thickness decreases, the amount of structural support provided by the support 20 to the barrel 15 decreases, and therefore deformations to the barrel 15 are more likely. Therefore, providing a support 20 with a wall thickness of no less than 0.5 mm may provide a good level of structural support.

The heating elements 17 have the form of resistive film heaters (for example, a thick-film or thin-film heater). As a result, a relatively low heat capacity may be achieved for the heating elements 17 which may improve the thermal responsiveness of the haircare appliance 10. Moreover, resistive film heaters may be more easily designed and manufactured to conform to the shape of the barrel 15. Thereby the heating elements 17 may be designed to provide relatively even distributed heating. This may reduce potential damage to hair that might arise due to local hot spots. However, other forms of heating element may be used such as foil heaters, tubular heating elements or coiled heating elements.

In the example above, the sensors 19 comprise temperature sensors for sensing the temperature of the barrel 15. However, in other examples the temperature of the barrel 15 may be measured indirectly by measuring the current drawn by a heating element 17, which (for a given voltage) is indicative of the resistance of the heating element 17. As hair comes into contact with the barrel 15, the temperature of the barrel 15 and the heating element 17 decreases. This decrease in temperature results in a decrease in the resistance of the heating element 17 and thereby an increase in the current drawn by the heating element 17. As hair departs the barrel 15, the inverse may occur. Thereby, the change in resistance may be used to determine the presence or absence of hair.

As mentioned above, the sensors 19 may comprise types of sensors other than temperature sensors. In one example, the sensors 19 comprise capacitive sensors. The presence or absence of hair in contact with a zone 21 may affect the capacitance of that zone, which may then be used by the capacitive sensors to determine the presence or absence of hair. In particular, the arrival of hair may increase the capacitance of a zone whilst the subsequent departure of hair may decrease the capacitance. In another example, the sensors 19 may comprise optical sensors. The arrival of hair may lead to a reduction in the irradiance measured by the optical sensor, whilst the subsequent departure of the hair may lead to an increase in the irradiance. This difference may then be used to determine the presence or absence of hair. In some applications, the use of types of sensors other than temperature sensors (such as optical or capacitive sensors) may achieve more reliable sensing.

Furthermore, in examples where the sensors 19 do not comprise temperature sensors, the haircare appliance 10 may comprise one or more temperature sensors in addition to the sensors 19 for sensing a parameter indicative of a presence or absence of hair. The temperature sensors may sense the temperature of the barrel 15 or heating elements 17. Thereby, the temperature sensors may be used in controlling the temperature of the heating elements 17, whilst the sensors 19 may be used to sense the arrival and/or departure of hair.

In the above example, the barrel assembly 11 is arranged such that the heating elements 17 and sensors 19 are located on the inside of the barrel 15. However, other arrangements are envisaged in which the sensors and heating elements are arranged differently. For example, the sensors and the heating elements may be located on the outside of the barrel. In another example, rather than locating the heating elements between the barrel and the sensors, the sensors may instead be located between the barrel and the heating elements In further examples, the sensors may be located inside of the support 20.

In the above example, the sensors 19 and heating elements 17 are located on different layers of the barrel assembly 11. However, in other examples, the sensors and heating elements may be co-located on a single layer.

An example of how the controller 33 controls the supply of electrical power to each of the heating elements 17 will now be described with the aid of Figures 4 and 5. In this example, the controller 33 employs multiple setpoints and controls the switches 29 such that the temperature of each of the heating elements 17 is maintained at the required setpoint. Although described in relation to a single heating element 17, the below example may be applied to multiple heating elements 17 simultaneously.

As shown in Figures 4 and 5, the controller 33 sets 201 the setpoint to a first setpoint value, Si.The first setpoint value may be, for example, 100 °C Then the controller 33 controls 203 the supply of electrical power to the heating element 17 to maintain the temperature of the heating element 17 at the first setpoint.

Next the controller 33 determines 205 if hair is present. As noted above, the controller 33 monitors the temperature of the heating element 17 and, in response to the temperature dropping below a threshold, the controller 33 determines that hair is present. If the controller determines that hair is not present, the controller 33 returns to controlling 203 the supply of electrical power to the heating element 17 to maintain the temperature of the heating element 17 at the first setpoint. If, on the other hand, the controller 33 determines that hair is present, the controller 33 increases 207 the setpoint from the first setpoint value to a second setpoint value, S2. The second setpoint value may be, for example, 180 °C. Then the controller 33 controls 209 the supply of electrical power to the heating element 17 to maintain the temperature of the heating element 17 at the second setpoint value.

Whilst maintaining the temperature of the heating element 17 at the second setpoint value, the controller 33 determines 211 if the hair is now absent, i.e., if the hair has been removed.

As noted above, the controller 33 monitors the temperature of the heating element 17 and, in response to the sensed temperature rising above a threshold, the controller 33 determines that the hair has been removed. If the controller 33 determines that the hair is still present, the controller 33 continues controlling 209 the supply of electrical power to the heating element 17 to maintain the temperature of the heating element 17 at the second setpoint value. If, on the other hand, the controller 33 determines that the hair is absent, the controller 33 decreases the setpoint to the first setpoint value, and the controller 33 then repeats the above steps.

With the control detailed above, the controller 33 monitors the arrival of hair and, in response, increases the temperature of the heating element 17 (i.e., to the second setpoint value). The controller 33 then monitors the subsequent departure of the hair and, in response, decreases the temperature of the heating element 17 (i.e., to the first setpoint value).

In the example described above with reference to Figures 4 and 5, the second setpoint value is constant and does not vary with time. However, in other examples, the setpoint may vary with time. For example, the second setpoint value may vary with time such that the temperature of the heating element follows a particular profile. This may increase the range of styling options that the haircare appliance can deliver.

Figure 6 shows an example method 100 which may be implemented by the hall-care appliance 10.

The method 100 comprises sensing 101 a parameter indicative of the presence or absence of hair in contact with a barrel of a haircare appliance. When implemented using the haircare appliance 10 described above, the sensors 19 may be used to sense a temperature of the heating elements 17. As noted above, the temperature of each of the heating elements 17 is sensitive to the presence and absence of hair.

The method 100 then comprises determining 103 the presence or absence of hair in contact with the barrel 15 based on the sensed property. Again, when implemented using the haircare appliance 10 described above, the controller 33 may be used to determine the presence or absence of hair based on an output of the sensors 19. For example, the controller 13 may determine the arrival of hair in response to a decrease in the temperatures of the heating elements, and the departure of hair in response to an increase in the temperatures of the heating elements.

The method 100 then comprises controlling 105 a supply of electrical power to a heating element of the haircare appliance based on the determination For example, when implemented using the haircare appliance 10 described above, the controller 33 may control the supply of electrical power to the heating elements 17 through the use of switches Whilst particular examples and embodiments have thus far been described, it should be understood that these are illustrative only and that various modifications may be made without departing from the scope of the invention as defined by the claims.

Claims

CLAIMS1. A haircare appliance comprising: a barrel around which hair may be wrapped; a heating element for heating the barrel; a sensor for sensing a parameter indicative of a presence or absence of hair in contact with the barrel; and a controller configured to: determine the presence or absence of hair in contact with the barrel based on data output by the sensor; and control a supply of electrical power to the heating element based on the determination.
2. A haircare appliance as claimed in claim 1, wherein: the haircare appliance comprises a further sensor for sensing a temperature of at least one of the barrel or heating element.
3. A haircare appliance as claimed in claim 1 or 2, wherein the controller is configured to increase the supply of electrical power to the heating element to increase the temperature of the heating element in response to determining the presence of hair in contact with the barrel or to decrease the supply of electrical power to the heating element to decrease the temperature of the heating element in response to determining the absence of hair in contact with the barrel.
4. A haircare appliance as claimed in claim 3, wherein the controller is configured to: control the supply of electrical power to the heating element to maintain the temperature of the heating element at a setpoint; and increase the setpoint in response to determining the presence of hair in contact with the barrel or decrease the setpoint in response to determining the absence of hair in contact with the barrel.
A haircare appliance as claimed in claim 4, wherein the controller is configured to: increase the setpoint from a first value to a second value in response to determining the presence of hair in contact with the barrel; and decrease the setpoint from the second value to the first value in response to determining the absence of hair in contact with the barrel.
6. A haircare appliance as claimed in any preceding claim, wherein: the barrel comprises a plurality of zones; the haircare appliance comprises: a plurality of heating elements, each heating element for heating a respective zone of the barrel; and a plurality of sensors, each sensor for sensing a parameter indicative of the presence or absence of hair in contact with a respective zone of the barrel; and the controller is configured to: determine the presence or absence of hair in contact with each of the zones of the barrel based on data output by the sensors; and control a supply of electrical power to each of the heating elements based on the determination.
7 A haircare appliance as claimed in claim 6, wherein, in response to determining the presence of hair in contact with one or more of the zones of the barrel, the controller is configured to increase the supply of electrical power to only those heating elements of the zones for which the presence of hair is determined
8. A haircare appliance as claimed in claim 7, wherein the controller is configured to: control the supply of electrical power to each of the heating elements to maintain the temperature of each of the heating elements at a respective setpoint; and increase the setpoint for only those heating elements of the zones for which the presence of hair is determined
9. A haircare appliance as claimed in claim 8, wherein, for only those heating elements of the zones for which the presence of hair is determined, the controller is configured to: increase the setpoint from a first value to a second value; and decrease the setpoint from the second value to the first value for only those heating elements of the zones for which the subsequent absence of hair is determined.
10. A haircare appliance as claimed in any of claims 6 to 9, wherein the plurality of zones comprises zones arranged longitudinally along a length of the barrel.
11. A haircare appliance as claimed in any of claims 6 to 10, wherein the plurality of zones comprises zones arranged circumferentially around the barrel.
12. A haircare appliance as claimed in any of claims 6 to 11 wherein the barrel comprises no less than 3 zones.
13. A haircare appliance as claimed in any of claims 6 to 12 wherein the barrel comprises no more than 24 zones.
14. A haircare appliance as claimed in any preceding claim, wherein the barrel has a wall thickness of no greater than 0.5 mm.
15. A haircare appliance as claimed in any preceding claim, wherein the barrel has a wall thickness of no less than 0.05 mm.
16. A haircare appliance as claimed in any preceding claim, wherein the haircare appliance comprises a support located inside of the barrel and having a wall thickness greater than a wall thickness of the barrel.
17. A haircare appliance as claimed in any preceding claim, wherein the heating element is attached directly to the barrel.
18. A haircare appliance as claimed in any preceding claim, wherein the heating element comprises a resistive film heater.
19. A method comprising: sensing a parameter indicative of a presence or absence of hair in contact with a barrel of a haircare appliance; determining the presence or absence of hair in contact with the barrel based on the sensed property; and controlling a supply of electrical power to a heating element of the haircare appliance based on the determination.