Field of the Invention

The present invention relates to an appliance, such as a haircare appliance.

Background of the Invention

Haircare appliances are generally used to treat or style hair, and some haircare appliances may treat or style hair using airflow and/or heat. Haircare appliances may be used to treat or style hair in a number of different ways, and some haircare appliances include different attachments to provide different treatment or styling functionality.

Summary of the Invention

According to a first aspect of the present invention there is provided an appliance comprising: a main unit to which one of a plurality of attachments is attachable; an emitter configured to emit optical radiation toward a respective one of the plurality of attachments when attached to the main unit; an optical sensor configured to receive optical radiation from the respective one of the plurality of attachments when attached to the main unit; and a control module configured to determine which of the plurality of attachments is attached to the main unit based on data output by the optical sensor.

By employing an emitter and optical sensor, the control module is able to determine remotely which of the attachments, if any, is in use. Rather than an emitter and optical sensor, the appliance could conceivably comprise alternative means for determining which attachment is in use. For example, the main unit could comprise electrical contacts or mechanical switches, and each attachment may contact a different set of contacts or actuate a different arrangement of switches when attached. In another example, the main unit could comprise one or more Hall-effect sensors, and each attachment may comprise a unique arrangement of magnets. In each of these examples, the contacts, switches or sensors would need to be located at the interface with the attachment. However, packaging additional components at the interface of the main unit may be challenging. For example, there may be insufficient space for the components and/or the required cabling, or the conditions at the interface and/or the path taken by the cabling may be harsh (e.g., high temperatures). By employing an emitter and optical sensor in the manner described above sensor, the optical sensor may be located remotely from the attachment and thus remotely from the interface. As a result, packaging of the optical sensor and routing of cables may be made easier. Moreover, the emitter and optical sensor are able to remotely sense different attachments without the need to provide the attachments with additional components, such as RFID tags or the like. Accordingly, different attachments may be sensed remotely in a relatively cost-effective manner.

The emitter and optical sensor may be packaged together in a sensor module, for example with the emitter and optical sensor mounted to a common printed circuit board.

The data output by the optical sensor may be based on a property of the optical radiation received by the optical sensor.

The optical radiation may be reflected from the respective one of the plurality of attachments when attached to the main unit. Alternatively, the respective one of the plurality of attachments may generate or emit the optical radiation.

The appliance may be a haircare appliance.

The appliance may comprise an electric component and the control module may be operable to control the electric component in response to the determination. The control module may therefore be able to control the electric component differently for different attachments. This then has the benefit that operation of the appliance may be controlled automatically on the basis of the attachment that is in use. The control module may be operable to control the input power to the electric component in response to the determination.

The electric component may be an electric motor or a heater, and the control module may be operable to control a speed of the electric motor or a temperature of the heater in response to the determination. The performance of the appliance may be improved by operating the electric motor at different speeds and/or by operating the heater at different temperatures based on the attachment that is in use. For example, the appliance may be a haircare appliance, the electric motor may be used to generate an airflow, and the heater may be used to heat the airflow. Different attachments may then provide better drying or styling results at different flow rates and/or at different heat settings.

The appliance may comprise an airflow generator for drawing an airflow through the appliance, and the control module may be operable to control a characteristic of the airflow in response to the determination. Different attachments may deliver better results for different airflows. For example, the appliance may be a haircare appliance and the attachments may comprise a diffuser and a concentrator. The diffuser may deliver better results when the airflow has lower flow rate. This is because the hair is moved less by the airflow and thus curls are better defined. By contrast, a concentrator may deliver better results when the airflow has a higher flow rate. For example, by employing a higher flow rate, drying and/or styling of the hair may be achieved more rapidly.

The control module may be operable to control one or more of a flow rate and a temperature of the airflow. As above, different attachments may deliver better results for different flow rates. Additionally or alternatively, different attachments may deliver better results for different temperatures. For example, the appliance may be a haircare appliance and at least one of the attachments may provide better styling results at a lower heat setting, and at least one of the attachments may provide better styling results at a higher heat setting. By controlling the flow rate and/or the temperature of the airflow in response to the attachment in use, better overall results may be achieved.

The appliance may be a haircare appliance comprising a plurality of flow and heat settings, and the control module may be operable to select one of the settings based on the determination. As above, different attachments may deliver better results for different flow and/or heat settings. Accordingly, by selecting one of the plurality of settings based on the attachment in use, better drying and/or styling results may be achieved.

The appliance may comprise a guide for at least one of: guiding emitted optical radiation from the emitter to the respective one of the plurality of attachments; and guiding reflected optical radiation from the respective one of the plurality of attachments to the optical sensor. By providing a guide, direct line of sight from the emitter to the attachment attached to the main unit, and/or from the attachment to the optical sensor, may be unnecessary, and this may provide increased flexibility in locating the emitter and/or optical sensor within the main unit. For example, where the appliance comprises a heater, this may enable electronic components such as the emitter and/or optical sensor to be located remotely from the heater. Furthermore, providing a guide for the optical radiation may enable the path of the optical radiation to be constrained, for example such that a user of the appliance is not exposed to the optical radiation in use.

Use of a guide may focus emitted optical radiation from the emitter toward the respective attachment to maximise the amount of reflected light received by the optical sensor, and minimise the amount of stray light received from other surfaces. This may result in higher signal to noise ratio, and may enable power consumption of the optical sensor to be minimised by reducing the power of optical radiation emitted by the emitter.

The guide may comprise an optical waveguide. The guide may comprise a light pipe. This may provide a relatively simple arrangement for guiding the optical radiation compared to, for example an arrangement comprising mirrors or lens or the like.

The guide may guide at least one of emitted optical radiation along a path from the emitter to the respective one of the plurality of attachments, and reflected optical radiation along a path from the respective one of the plurality of attachments to the optical sensor.

The guide may guide at least one of: emitted optical radiation along a non-linear path from the emitter to the respective one of the plurality of attachments; and reflected optical radiation along a non-linear path from the respective one of the plurality of attachments to the optical sensor. Guiding the emitted and/or reflected optical radiation along a non-linear path may provide flexibility in location of the emitter and/or the optical sensor within the main unit, for example in comparison to an arrangement where a linear path is required.

The main unit may comprise a heater, and at least one of the emitter, the optical sensor, and the control module, may be located in a region of the main unit thermally insulated from the heater. For example, there may be at least one wall of thermally insulating material, such as a plastics material, between the heater and the at least one of the emitter, the optical sensor, and the control module. This may enable operation of the at least one of the emitter, the optical sensor, and the control module whilst mitigating risk of damage from the heater.

The appliance may comprise an air outlet for emitting airflow into the plurality of attachments, the heater may be upstream of the air outlet, and the at least one of the emitter, the optical sensor, and the control module may be remote from the air outlet.

The data output by the optical sensor may be based on a property of the reflected optical radiation received by the optical sensor.

The data output by the optical sensor may be indicative of an intensity of the reflected optical radiation. Intensity of the reflected optical radiation may provide a relatively straightforward means to distinguish between attachments, for example in comparison to a mechanism where physical contacts or magnetic field determinations are utilised.

The data output by the optical sensor may be indicative of a wavelength of the reflected optical radiation, for example indicative of a colour of the reflected optical radiation where the reflected optical radiation is in the visible light spectrum. A wavelength of the reflected optical radiation may provide a relatively straightforward means to distinguish between attachments, for example in comparison to a mechanism where physical contacts or magnetic field determinations are utilised.

The appliance may comprise the plurality of attachments, and each of the plurality of attachments may comprise a reflector and a filter configured such that the plurality of attachments each provide a different intensity of reflected optical radiation to the optical sensor when attached to the main unit. A filter may provide a convenient and relatively inexpensive way in which to provide a variation in intensity of reflected light between different attachments. Each of the plurality of attachments may comprise an array of filters, for example an array of at least two filters. Use of an array of filters may enable distinction between attachments irrespective of relative rotational orientation of an attachment to the main unit. The filter may comprise a polarizer. The emitter may comprise an infra-red emitter, and the data output by the optical sensor may be indicative of an intensity of reflected infra-red radiation from the respective one of the plurality of attachments when attached to the main unit. Use of an infrared emitter may ensure that the emitted and/or reflected infrared radiation is not visible to a user.

The appliance may comprise the plurality of attachments, and each of the plurality of attachments may comprise a reflector configured such that plurality of attachments each provide a different intensity of reflected optical infra-red radiation to the optical sensor when attached to the main unit. This may provide a relatively straightforward means to distinguish between attachments, for example in comparison to a mechanism where physical contacts or magnetic field determinations are utilised.

At least some of the reflectors may have a different surface area. At least some of the reflectors may have a different surface finish. At least some of the reflectors may be formed of a different material. At least some of the reflectors may be located on the respective attachment such that, when the respective attachment is attached to the main unit, a distance between the emitter and the reflector is different for different attachments. Any of the aforementioned may provide relatively simple and/or inexpensive ways to vary intensity of reflected infrared variation, and hence provide a relatively simple and/or inexpensive way to determine which of the plurality of attachments is attached to the main unit.

Each of the reflectors may have a different surface area. Each of the reflectors may have a different surface finish. Each of the reflectors may be formed of a different material. Each of the reflectors may be located on the respective attachment such that, when the respective attachment is attached to the main unit, a distance between the emitter and the reflector is different for different attachments. The emitter may comprise a visible light emitter, and the data output by the optical sensor may be indicative of an intensity of reflected visible light from the respective one of the plurality of attachments when attached to the main unit. For example the emitter may comprise an LED. Such a visible light emitter may provide a relatively simple and/or inexpensive way to determine which of the plurality of attachments is attached to the main unit, and which may be more reliable than, for example, an arrangement where physical mechanical contacts need to be utilised.

The data output by the optical sensor may be indicative of an intensity of different colour components of reflected visible light from the respective one of the plurality of attachments when attached to the main unit. Monitoring different colour intensities may provide a relatively simple and/or inexpensive way to determine which of the plurality of attachments is attached to the main unit, and which may be more reliable than, for example, an arrangement where physical mechanical contacts need to be utilised.

The appliance may comprise the plurality of attachments, each of the plurality of attachments may comprise a reflector, and each of the reflectors may be a different colour. Providing different coloured reflectors on the attachments may provide a relatively simple and/or inexpensive way to determine which of the plurality of attachments is attached to the main unit when compared to, for example, an arrangement where the plurality of attachments are required to communicated, either wired or wirelessly, with the main unit.

The emitter may be configured to emit white visible light, and the optical sensor may comprise a plurality of sensors, for example a plurality of photodiodes, and a plurality of filters, each filter associated with a respective sensor, each sensor configured to provide an output based on an intensity of light of a given colour to which the respective filter corresponds. Use of an emitter that emits white visible light may provide a simpler arrangement than, for example, an arrangement utilising an emitter that has to be controlled to emit different coloured lights at different times.

The emitter may be configured to selectively emit different coloured lights, and the optical sensor may comprise a wideband sensor, for example a wideband phot transistor, configured to detect an intensity of different colour components of reflected visible light from the respective one of the plurality of attachments when attached to the main unit.

The appliance may comprise the plurality of attachments, at least some of the plurality of attachments may comprise a portion of optically transparent material, the appliance may comprise a further emitter configured to emit further optical radiation toward a respective portion of optically transparent material of one of the plurality of attachments when attached to the main unit, a further optical sensor configured to receive reflected optical radiation from an object external to the appliance through the respective portion of optically transparent material ; and a further control module configured to determine a property of the object based on further data output by the further optical sensor. This may enable the appliance to both determine which attachment is attached to the main unit, alongside a property of an object external to the appliance. For example, the property of the object may comprise any of a presence or absence of the object, a type of the object, a distance of the object from the main unit, a distance of the object from the attachment, a temperature of the object, and a moisture content of the object. The further emitter and the further optical sensor may comprise a time-of-flight sensor. The further control module and the control module may be the same control module.

The appliance may comprise an electric component and the further control module may be operable to control the electric component in response to the determination of the property of the object. The further control module may therefore be able to control the electric component differently for different properties of external objects.

The electric component may be an electric motor or a heater, and the further control module may be operable to control a speed of the electric motor or a temperature of the heater in response to the determination of the property of the object.

The appliance may comprise an airflow generator for drawing an airflow through the appliance, and the further control module may be operable to control a characteristic of the airflow in response to the determination of the property of the object.

The further control module may be operable to control one or more of a flow rate and a temperature of the airflow.

The appliance may be a haircare appliance comprising a plurality of flow and heat settings, and the further control module may be operable to select one of the settings based on the determination of the property of the object.

The main unit may comprise a barrel section having a central bore, the plurality of attachments may be attachable to an end of the barrel section, and at least one of the emitter and the optical sensor may be located within the bore. This may provide a direct, unobstructed path between the emitter and the attachment, and/or between the attachment and the optical sensor. Additionally, emissions may be better confined within the appliance. Furthermore, for appliances that already have an existing bore, the emitter and/or optical sensor may be incorporated without increasing the overall size of the appliance. At least one of the further emitter and the further optical sensor may be located within the bore.

Brief Description of the Drawings Figure 1 is a schematic view of a first embodiment of a haircare appliance;

Figure 2 is a schematic sectional view of a main unit of the haircare appliance of Figure 1 ;

Figure 3 is a schematic rear view of the main unit of Figure 2;

Figure 4 is a schematic illustration of a sensor assembly of the haircare appliance of Figure 1 ;

Figure 5 is a schematic illustration of attachments of the haircare appliance of Figure 1 ;

Figure 6 is a schematic illustration of the haircare appliance of Figure 1 when an attachment is attached to the main unit;

Figure 7 is a schematic illustration of RGB colour profiles of light reflected by attachments of the haircare appliance of Figure 1 ;

Figure 8 is a schematic view of a second embodiment of a haircare appliance;

Figure 9 is a schematic view of a third embodiment of a haircare appliance;

Figure 10 is a schematic illustration of an attachment of the haircare appliance of Figure 9;

Figure 11 is a schematic illustration of intensity profiles of light reflected by attachments of the haircare appliance of Figure 9;

Figure 12 is a schematic view of a fourth embodiment of a haircare appliance; Figure 13 is a schematic illustration of an attachment of the haircare appliance of

Figure 12; and

Figure 14 is a schematic illustration of intensity profiles of infra-red radiation reflected by attachments of the haircare appliance of Figure 12.

Detailed Description of the Invention

A first embodiment of an appliance 10, in the form of a haircare appliance, is illustrated schematically in Figures 1 -3. The appliance 10 comprises a main unit 12, and a plurality of attachments 14,16, each of which is attachable to the main unit 12. Here the attachments 14,16 comprise a concentrator 14 and a diffuser 16, although it will be appreciated that other types of attachment are envisaged.

The main unit 12 is shown schematically in isolation in Figures 2 and 3, and comprises a handle portion 18, a head portion 20, an airflow generator 22, a heater 24, user controls 26, a control module 28, an emitter 30, an optical sensor 32, a light guide 34, and a time-of-flight sensor 36.

The handle portion 18 is generally cylindrical and hollow in form, and houses the airflow generator 22. The handle portion 18 has an air inlet 38 in the form of a plurality of perforations at a first end 40 of the handle portion 18.

The head portion 20 is generally cylindrical and hollow in form, and is disposed at a second end 42 of the handle portion 18, with a central axis of the head portion 20 orthogonal to a central axis of the handle portion 18 such that the main unit 12 is generally T-shaped in form. The head portion 20 houses the heater 24. The head portion 20 comprises a bore 44 through which air is entrained, and an air outlet 46. The air outlet 46 is generally annular in form about a periphery of the bore 44. The head portion 20 further comprises an annular magnet (not shown) for releasably connecting the handle unit 12 to the attachments 14,16. The annular magnet extends annularly about the air outlet 46.

The user controls 26 are provided on both the handle portion 18 and the head portion 20, and comprise a first button 48 or slider to power on and off the appliance 10, a second button 50 to momentarily power off the heater 24 such that the appliance 10 delivers a cold shot of air, a third button 52 to control the flow rate of the airflow, and a fourth button 54 to control the temperature of the airflow.

The control module 28 is responsible for controlling the airflow generator 22 and the heater 24 in response to inputs from the user controls 26. For example, in response to inputs from the user controls 26, the control module 28 may power on and off the airflow generator 22 and/or the heater 24. Additionally, the control module 28 may control the power or speed of the airflow generator 22 in order to vary the flow rate of the airflow. For example, repeatedly pressing the third button 52 may cause the control module 28 to cycle through different flow rates (e.g., low, medium and high). Similarly, the control module 28 may control the power of the heater 24 in order to vary the temperature of the airflow. For example, repeatedly pressing the fourth button 54 may cause the control module 28 to cycle through different temperature settings (e.g., cold, warm, hot).

The control module 28 further controls the airflow generator 22 and the heater 24 in response to inputs from the optical sensor 32 and the time-of-flight sensor 36, as will be discussed in more detail hereafter.

The emitter 30 and optical sensor 32 are combined into a sensor assembly 56 located within the bore 44 of the head portion 20, with the sensor assembly 56 illustrated schematically in Figure 4. The sensor assembly 56 is located at a radially outer position of the bore 44. The emitter 30 comprises an LED configured to emit white light, and the optical sensor 32 comprises three photodiodes 58, each covered with a different colour filter 60. In particular, the photodiodes 58 are covered with a red filter (indicated by dotted shading), a blue filter (indicated by hashed shading), and a green filter (indicated by vertical line shading).

In the embodiment of Figures 1 -3, the emitter 30 comprises a white LED and the optical sensor 32 comprises the three photodiodes 58, each covered with a different colour filter 60. In alternative embodiments of the appliance 10, the emitter can comprise an LED configured to emit different colours of light, for example red, green and blue light, and the optical sensor can comprise a wideband photo transistor configured to detect an intensity of the different colour components of reflected visible light from the attachments.

The light guide 34 extends from the sensor assembly 56 linearly along the bore 44 toward the periphery of the bore 44 where the air outlet 46 is located. The light guide 34 is generally cylindrical in form, and is formed of a material having a relatively high refractive index, of around 1 .4-1 .6, when compared to air, which has a refractive index of around 1. Example materials include polydimethylsiloxane (PDMS) or an acryl material the skilled addressee will understand that any similar material which has high refractive index could be used. The light guide 34 is open in the region of the bore 44 adjacent to the air outlet 46.

The time-of-flight (TOF) sensor 36 is located within the bore 44 along a central axis of the bore 44, such that the time-of-flight sensor 36 is located radially inwardly of the sensor assembly 56.

Each of the concentrator and diffuser attachments 14,16 is formed of an optically transparent material, yet also comprises a respective annular reflector 62,64, as illustrated schematically in Figure 5. As an example, the annular reflector 62 of the concentrator attachment 14 is red coloured (indicated by dotted shading), whilst the annular reflector 64 of the diffuser attachment 16 is blue coloured (indicated by hashed shading). The annular reflectors 62,64 are positioned on the respective concentrator and diffuser attachments 14,16 such that they overlie the open end of the light guide 34 when the attachment 14,16 is attached to the head portion 20 of the main unit 12, irrespective of the rotational orientation of the attachment 14,16 relative to the head portion 20.

The annular reflector can be any colour that allows different levels or ratios of reflected light wavelengths so as to allow a distinct discrimination between attachments

In use, one of the attachments 14,16 is attached to the head portion 20 of the main unit 12, with such a configuration illustrated schematically with the concentrator attachment 14 in Figure 6. The control module 28 can determine which of the attachments 14,16 is attached to the main unit 12, and can control the appliance 10 accordingly. In particular, the sensor assembly 56 and the annular reflectors 62,64 can be utilised to determine which of the attachments 14,16 is attached to the main unit 12.

The emitter 30 emits white light, which is guided by the light guide 34 within the bore 44 toward the annular reflector 62,64 of the attachment 14,16. The white light is reflected by the annular reflector 62,64, and guided by the light guide 34 toward the photodiodes 58 of the optical sensor 32. As the annular reflectors 62,64 of the attachments 14,16 are of different colours, the reflected light from each annular reflector 62,64 will have a different RGB colour profile, e.g. with different intensities present for different wavelengths of light, and the photodiodes 58 are utilised to determine RGB light intensity of the reflected light. Either the optical sensor 32 itself, or the control module 28, can determine an RGB colour profile of the reflected light based on photons received by the photodiodes 58, and the control module 28 can then determine which of the attachments 14,16 is attached to the main unit 12 based on the colour profile of the reflected light. For example, the determination may be made by comparison to threshold values, for example threshold values or ranges for each of red, green, and blue light received, or pre-determined colour profiles. The control module 28 then uses this determination to control the flow rate and/or the temperature of the airflow, as described further below.

Illustrative RGB colour profiles are shown schematically in Figure 7. Here the left peaks have a highest response intensity for red light, indicating the red annular reflector 62, whilst the right peaks have a highest response intensity for blue light, indicating the blue annular reflector 64.

The TOF sensor 36 is used to sense the proximity of a user’s head or other object to the appliance 10. In the present example, the control module 28 analyses the distance data output by the TOF sensor 36 and from this analysis determines the proximity of the head of a user. In other examples, the TOF sensor 36 itself, rather than the control module 28, may analyse the distance data and output data indicative the proximity of a user’s head. In each of these examples, the control module 28 nevertheless determines the proximity of the user’s head based on the data received from the TOF sensor 36. The control module 28 then uses this determination to control the flow rate and/or the temperature of the airflow.

As indicated above, the control module 28 controls the airflow generator 22 and the heater 24 in response to inputs from the optical sensor 32 and the time-of- flight sensor 36. As a result, better drying and/or styling results may be achieved. For example, different attachments may deliver better drying or styling results when using different flow rates and/or temperatures. The diffuser attachment 16, for example, is likely to deliver better results when the airflow has a lower flow rate. By employing a lower flow rate, the hair is moved less by the airflow and thus curls may be better defined. By contrast, the concentrator attachment 14 is likely to deliver better results when the airflow has a higher flow rate. In another example, if the head of the user is too close to the appliance, a high flow rate may move the hair excessively resulting in unsatisfactory styling results and/or a high temperature may over-dry or damage the hair. Accordingly, by controlling the flow rate and/or the temperature of the airflow based on which attachment 14,16, if any, is attached and/or the proximity of the head of the user, better styling results may be achieved.

The control module 28 may store a plurality of different flow and temperature settings, and the control module 28 may select one of the plurality of settings based on which of the attachments 14,16 is attached to the main unit. For example, the control module 28 may store a default flow and temperature setting for each of the attachments 14,16. Additionally, or alternatively, the control module 28 may store the flow and temperature setting selected by a user when last using a particular attachment 14,16.

In such a manner, appropriate flow and/or temperature settings can be determined for a particular attachment 14,16 and/or for a particular distance at which a user’s head is located relative to the appliance. Use of the emitter 30 and the optical sensor 32 may provide an attachment recognition system having components located remotely from the attachment and thus remotely from the interface between the main unit 12 and the attachments 14,16. As a result, packaging of the optical sensor 32 and routing of cables may be made easier. Moreover, the emitter 30 and optical sensor 32 may be able to remotely sense different attachments 14,16 without the need to provide the attachments14,16 with additional components such as RFID tags or the like. Accordingly, different attachments 14,16 may be sensed remotely in a relatively cost-effective manner.

Through use of the light guide 34, the emitter 30 and optical sensor 32 may be utilised alongside the TOF sensor 36, with the light guide 34 inhibiting interference between the optical emissions utilised by the emitter 30 and the TOF sensor 36. This may allow the sensor assembly 56 and the TOF sensor 36 to both be located within the bore 44 of the head portion 20 of the handle unit 12, where they may be thermally insulated from the heater 24. Furthermore, use of the light guide 34 may focus emitted light from the emitter 30 toward the respective annular reflector 62,64 to maximise the amount of reflected light received by the optical sensor 32, and minimise the amount of stay light received from other surfaces. This may result in higher signal to noise ratio, and may enable power consumption of the sensor assembly 56 to be minimised by reducing the power of light emitted by the emitter 30.

Furthermore, it will be appreciated that although there are two attachments 14,16 shown in Figure 1 , greater numbers of attachments may be utilised with the main unit 12, with each attachment having a different coloured annular reflector.

A second embodiment of an appliance main unit 200, in the form of a haircare appliance main unit, is illustrated schematically in Figure 8, where like reference numerals are used for sake of clarity.

Here, rather than being positioned in the bore 44, the sensor assembly 56 is located within a housing 202 of the head portion 20, rearwardly of the heater 24, and toward the user controls 26. The light guide 204 is non-linear in form, and extends from within the housing 202 to a radially outer position of the bore 44, before extending along the bore 44 toward the periphery of the bore 44 where the air outlet 46 is located. Use of the non-linear light guide 204 may provide increased flexibility in locating the sensor assembly 56 within the appliance 10, and may enable removal of the sensor assembly 56 from the bore 44.

A third embodiment of an appliance 300, in the form of a haircare appliance, is illustrated schematically in Figure 9, where like reference numerals are used for sake of clarity. The third embodiment of the appliance 300 differs from the first 10 and second 200 embodiments of the appliance in the form of the sensor assembly 302 and the attachments 304,306.

The sensor assembly 302 comprises an emitter 308 and an optical sensor 310. The emitter 308 comprises an LED configured to emit visible light, and the optical sensor 310 comprises an appropriate sensor to sense an intensity of reflected visible light from the attachments 304,306.

The attachments 304,306 respectively comprise a concentrator attachment 304 and a diffuser attachment 306. Each of the attachments 304,306 has an annular reflector 312 formed of a foil material, and first 314 and second 316 annular polariser films, with such an arrangement illustrated schematically for the concentrator attachment 304 in Figure 10. The annular reflector may be made out of any highly reflective material, At least one of the first 314 and second 316 polariser films is different between the attachments 304,306, for example orientated differently, such that each of the attachments 304,306 provides a different intensity of reflected light to the optical sensor 310.

Either the optical sensor 310 itself, or the control module 28, can determine an intensity profile of the reflected light based on photons received by the optical sensor 310, and the control module 28 can then determine which of the attachments 304,306 is attached to the main unit 12 based on the intensity profile of the reflected light, for example by comparison to threshold values or predetermined intensity profiles. The control module 28 then uses this determination to control the flow rate and/or the temperature of the airflow, as described above for the first embodiment 10 of the appliance. Illustrative intensity profiles are shown for four attachments A-D in Figure 11 .

Similar to the first 10 and second 200 embodiments of the appliance described above, use of intensity profiles of reflected light may provide an attachment recognition system having components located remotely from the attachment and thus remotely from the interface between the main unit 12 and the attachments 304,306, with the benefits that such an arrangement provides.

A fourth embodiment of an appliance 400, in the form of a haircare appliance, is illustrated schematically in Figure 12, where like reference numerals are used for sake of clarity.

The fourth embodiment of the appliance 400 differs from the first 10 and second 200 embodiments of the appliance in the form of the sensor assembly 402 and the attachments 404,406.

The sensor assembly 402 comprises an emitter 408 and an optical sensor 410. The emitter 408 comprises an infra-red LED configured to emit infra-red radiation, and the optical sensor 410 comprises an appropriate sensor to sense an intensity of reflected infra-red radiation from the attachments 404,406.

The attachments 404,406 respectively comprise a concentrator attachment 404 and a diffuser attachment 406. Each of the attachments 404,406 has an annular reflector 412, with such an arrangement illustrated schematically for the concentrator attachment 404 in Figure 13. The reflectors 412 are different between the attachments 404,406, such that each of the attachments 404,406 provides a different intensity of reflected light to the optical sensor 410. The annular reflectors 412 can provide different intensities of reflected light in a number of ways. Possible variations in the annular reflectors 412 include any or any combination of variations in surface area, variations in surface finish, variations in material, and variation in position of the annular reflector 412 on the attachment 404,406 such that distance of the annular reflector 412 from the optical sensor 410 varies when the attachment 404,406 is attached to the main unit 12. Either the optical sensor 410 itself, or the control module 28, can determine an intensity profile of the reflected infra-red radiation based on infra-red radiation received by the optical sensor 410, and the control module 28 can then determine which of the attachments 404,406 is attached to the main unit 12 based on the intensity profile of the reflected infra-red radiation, for example by comparison to threshold values or pre-determined intensity profiles. The control module 28 then uses this determination to control the flow rate and/or the temperature of the airflow, as described above for the first embodiment 10 of the appliance. Illustrative intensity profiles for two attachments E,F are shown schematically in Figure 14.

Similar to the first 10 and second 200 embodiments of the appliance described above, use of intensity profiles of reflected infra-red radiation may provide an attachment recognition system having components located remotely from the attachment and thus remotely from the interface between the main unit 12 and the attachments 404,406, with the benefits that such an arrangement provides.

In the examples described above, the appliances 10,200,300,400 are haircare appliances that emit an airflow for drying and styling hair. The control module 28 of the appliances 10,200,300,400 then controls the flow rate and/or the temperature of the airflow based on data output by the optical sensor. In particular, the flow rate and/or the temperature may be controlled according to which attachment, if any, is in use. Additionally, the flow rate and/or the temperature may be controlled according to the proximity of a user’s head to the appliances 10,200,300,400, as determined by the TOF sensor 36.

The principles described above may be used with other types of appliance having a plurality of different attachments. For example, the appliance may be a vacuum cleaner having a main unit to which one of a plurality of different attachments may be attached. The main unit may comprise an airflow generator that generates suction at each of the attachments. The attachments may comprise a first suction nozzle for use on floors, and a second suction nozzle for use on upholstery. When used on floors, a higher suction may be beneficial to draw in more of the dirt. However, when used on upholstery, a higher suction may cause the upholstery to be sucked into and block the suction nozzle. Accordingly, better results may be achieved on upholstery with a lower suction. The main unit may therefore comprise an optical sensor that senses which of the attachments is attached, and a control module that controls the suction of the airflow generator based on the data output by the optical sensor. In another example, the appliance may be a power tool or the like that comprises an electric motor for driving different attachments. An optical sensor may sense which of the attachments is attached, and a control module may control the speed and/or torque of the electric motor based on the data output by the optical sensor. Accordingly, in a more general sense, the appliance may be said to comprise a main unit to which one of a plurality of attachments is attachable. The appliance comprises an optical sensor and a control module that is operable to determine which of the plurality of attachments is attached to the main unit based on data output by the optical sensor. The control module may then control an electrical component (e.g., an electric motor, an airflow generator or a heater) in response to the determination.

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.