WO2025061657A1

WO2025061657A1 - Hair styling device

Info

Publication number: WO2025061657A1
Application number: PCT/EP2024/075863
Authority: WO
Inventors: Nicola LEYS; Michaël DE MEUE; Brecht NUYTTENS; Maarten DE VRIENDT
Original assignee: Sinelco International BV
Current assignee: Sinelco International BV
Priority date: 2023-09-19
Filing date: 2024-09-17
Publication date: 2025-03-27
Anticipated expiration: 2026-03-19
Also published as: WO2025061658A1; WO2025061656A1; WO2025061659A1; WO2025061655A1

Abstract

Hair styling device comprising a main body having a back end and a front end, the front end including an air exit, wherein the main body is configured to guide air from an air entrance to the air exit; the hair styling device further comprising a handle attached to the main body.

Description

HAIR STYLING DEVICE

Field of the Invention

[01] The present invention generally relates to a hair styling device, in particular to a professional hair styling device for use in a hairdressing salon.

Background of the Invention

[02] Hair styling devices are generally known electric devices and may be configured to blow heated air through a main body. The heated air can be directed to a person’s hair to dry and style the hair. Hair styling devices can be handheld devices, including a handle mounted substantially transversely to the main body. Other handheld hair styling devices may include a pair of movable jaws in between which hair can be clamped such that it can be styled. Alternatively, hair styling devices may be standalone devices and may for example include a headset, such as hood hair dryers. Hair styling devices may come in various types, such as a personal hair styling device, for example for occasional use at home generally by a person drying and/ or styling its own hair, a travel hair styling device which may for example be relatively small, lightweight and/or foldable for easy transportation, or a professional hair styling device which may be used by a person styling someone else’s hair, for example in a professional setting, used by a hairdresser in a hairdressing salon. Each of these various types of hair styling devices can include specific technical requirements due to the different use made of said type of hair styling devices.

[03] In the field of professional hair styling devices, which are generally used by a hairdresser drying and/or styling a client’s hair in a professional context, such as in a hairdressing salon, in photo studios, before fashion shows, in education, or in any other professional context, ergonomics may be an issue given the intensive use of the hair styling device by the hairdresser. It is known that professional hair styling devices may be relatively heavy and/or bulky, which may cause physical discomfort for the hairdresser, for example at a hairdresser’s hand, wrist, arm and/or back. A further issue may be robustness and safety of a professional hair styling device. Since the hair styling device is intensively and/or frequently used, requirements with respect to robustness and safety of exterior and interior parts to improve life expectancy of the hair styling device may be more difficult to achieve than for regular home-used hair styling devices. Another issue can be that known hair styling devices may be relatively limiting in use due to a combination of predetermined parameters, such as air flow and/or temperature, which may not be optimal for a certain situation or hair type. At the same time, especially in professional user environments, it is important that hair styling devices can be operated and controlled with relatively low effort, and that operation is intuitive to the user.

[04] It is therefore an aim of the present invention to solve or at least alleviate one or more of the above-mentioned problems. In particular, the invention aims at providing an improved hair styling device, in particular for professional use, which is relatively easy to handle while remaining versatile in use, and which can improve ergonomics and safety during prolonged use.

Summary of the Invention

[05] To this aim, according to a first aspect of the invention, there is provided a hair styling device having the features of claim 1. In particular, the hair styling device comprises a main body having a back end and a front end, the front end being opposite the back end, and the front end including an air exit. The main body is configured to guide air from an air entrance to the air exit. The air entrance can be located in the main body, for example laterally, circumferentially or at the back end, or in a handle. The main body can include a housing at least partially enclosing for example a motor block and heating elements configured to heat air such that the air exiting the main body has a desired temperature which is higher than an air temperature at the air entrance. The hair styling device further comprises a handle attached to the main body and configured to hold the hair styling device by hand. The handle can for example be mounted substantially transversely to the main body. The handle may preferably be fixedly attached to the main body. Alternatively, the handle may be tiltable or foldable with respect to the main body, for example to allow compact storing of the hair styling device. In an inventive way, the hair styling device includes a display positioned at the back end of the main body. The display is advantageously tilted with respect to a plane substantially transverse to a longitudinal axis of the main body. The display can allow to show useful information, such as air exit temperature or air flow or other relevant parameters, to the user holding the hair styling device, in particular to a user styling hair of another person. The tilt of the screen can improve readability of the screen for the user, at least partially preventing an unfavourable posture of the user of the hair styling device.

[06] The display is preferably tilted over a tilt angle comprised between more or less 5° to more or less 20°, more preferably over an angle around 10° with respect to the plane substantially transverse to the longitudinal axis of the main body. Such an angle can optimize a vertical viewing angle of a user on the screen. Said tilt angle can be a fixed tilt angle. Alternatively, a tilt angle of the screen may be adjustable, for example by having a tiltable screen, for example within a range of more or less 5° to more or less 20°.

[07] A lower side of said display is advantageously offset from said plane substantially transverse to said longitudinal axis of the main body and including an upper side of said display, said offset being in a direction away from the handle. The lower side of the display is the side of the display which is closest to the handle of the hair styling device. By offsetting the lower side of the display in a direction away from the handle, the tilt of the display causes the display to be oriented slightly upwardly when the handle is in a substantially vertical position and under the main body. This orientation of the tilt of the display can provide a relatively well readability of the display in a range of typical orientations of the hair styling device during use. It is for example rather unusual to use the hair styling device with the handle in a substantially vertical position and on top of the main body during a prolonged time, in which case the display may be oriented downwardly. Considering that the longitudinal axis through the main body is a roll axis and that the handle is a yaw axis, the hair styling device generally describes a rolling movement to the right and to the left of more or less maximum 90° while the handle remains substantially lower than the main body during normal use of the hair styling device by a professional hairdresser styling a client’s hair.

[08] A viewing angle, in particular a horizontal viewing angle, of the display may be higher than 159°, preferably higher than 169°. A viewing angle of the display can be defined as a range of angles from which an image on the display can be suitably viewed by a user. Said relatively large horizontal viewing angles can for example be obtained by using a liquid-crystal display (LCD), for example a thin-film-transistor liquid-crystal display (TFT), or an organic light-emitting diode display (OLED), or any other suitable monitor technology. A wide viewing angle of the display can facilitate reading of information displayed on the screen during use when the hair styling device can continuously be moved in various positions. A relatively wide vertical viewing angle of the display may be favourable as well.

[09] The display may for example be a substantially circular display. The shape of the display can preferably be substantially similar to a shape of the back end of the main body of the hairstyling device. A substantially circular display can allow a maximisation of surface of the display allowing an increase of data to be potentially displayed. Moreover, a substantially circular shape can minimize turbulence of air around the display and thus minimize noise due to said turbulence. The shape of the display and/or of the back end of the hair styling device can alternatively be different from a substantially circular shape and have any other known shape, such as for example a substantially square or rectangular shape.

[10] The main body can further comprise a wedge-shaped end piece. Said end piece may be detachably mountable to the back end of the main body, for example via a click system or via any other known detachable attachment means, which can preferably allow a relatively quick and toolless mounting and/or unmounting. The detachable mounting can allow a relatively easy cleaning of the end piece, for example freeing the end piece from accumulated dust. The wedge-shaped form of the end piece can at least partially prevent the display from protruding from the back end of the main body of the hair styling device. In this way, said end piece can provide additional protection to the back end, the air entrance and to the display.

[11] An angle of the wedge-shaped end piece, as well as an orientation of said angle, can preferably be substantially equal to a tilt angle of the display with respect to the plane substantially transverse to said longitudinal axis of the main body. In this way, the display can be substantially flush with said wedge-shaped end piece when said end piece is mounted to the back end of the main body. When the angle of the wedge, and/or when the orientation of the wedge, is different from an angle and/or an orientation of the tilt angle of the display, the display will at least partially protrude from said end piece.

[12] The back end of the main body may additionally include the air entrance. In this way, the air flow from the air entrance to the air exit can follow a path including a minimum of changes of direction, more or less in parallel with the main body, or the housing of the hair styling device. Alternatively, the hair styling device can include a lateral air entrance or a substantially circumferential air entrance, or an air entrance in the handle, such that the presence of the display at the back end of the hair styling device does not hinder air intake.

[13] Said end piece can advantageously include a filter configured to filter incoming air. Said filter may be included in a base of the wedge or, more preferably, in or near the tilted surface of the wedge-shaped end piece. Said filter may for example be a ring- shaped filter having a ratio of open surface to closed surface of more or less 40% to more or less 80%. When the filter is included in the tilted surface, and when the filter has a relatively high ratio of open surface configured to filter large particles of dust, the end piece may include a second filter, for example just behind the filtering surface of the end piece, which second filter may for example be a mesh configured to filter relatively small particles. A cross-section of said ring-shaped filter can preferably be concave or, alternatively, convex, thus further maximizing a surface of the filter over a flat filter.

[14] The display may be positioned substantially centrally in front of the air entrance partially blocking air intake. In other words, a central longitudinal axis of the main body goes through the display. So, the display may not be, or may only be a little bit, laterally offset towards a predetermined side of the main body or of the back end of the hair styling device. Since the back end of the hair styling device includes the air entrance, the display can block at least partially said air entrance, in particular a substantially central portion of said air entrance. As a result, a useful portion of the air entrance is substantially surrounding said display, for example in a ring-shaped way depending on a shape of the display. The air entrance can thus be a substantially ring-shaped air entrance for a substantially circular display. Said substantially central position of the display can provide a substantially equal distribution of the air intake from all sides. At the same time, a reduced air entrance can accelerate air at air intake.

[15] The air entrance may advantageously include two substantially truncated conical portions connected by a flange. An exterior truncated conical portion, as seen in a direction of air flow, may have a smallest diameter which is larger than a widest diameter of an interior truncated conical portion. The flange can then extend substantially inwardly from the smallest end of the exterior truncated conical portion and connect to a widest end of the interior conical portion. Said flange may thus be a ring-shaped flange and may be substantially transverse to said longitudinal axis of the main body. The double truncated conical portions and said flange can allow a relatively large air intake while keeping a diameter of the base of the air entrance relatively small. At the same time, the flange can provide a narrowing in the air intake, in particular between an outward side of said flange and an inner side of the housing, which narrowing can increase air speed of incoming air. Additionally, the flange can prevent air from exiting again via the air entrance and can help air being trapped and be sent towards a fan of the hair styling device. Alternatively, an air entrance shaped as a single truncated conical portion is possible as well. In fact, the specific shape of the air entrance, as described in the present and the following paragraphs, can be considered as a separate invention and can be applied to any air entrance of a hair styling device including a substantially central obstruction of the air intake such that a useful portion of the air entrance surrounds the obstruction. In case of a substantially circular obstruction, the air entrance can for example be a substantially ring-shaped air entrance. The substantially central obstruction can be formed by any mechanical element, not only by a display or a housing including a display, for example by a housing for a mirror, a watch, a logo, a picture or any other element.

[16] The display can be included in a housing, the housing being positioned at a distance of a base of the air entrance. The housing may for example have a similar shape as the display, for example a substantially circular shape. The housing of the display may preferably be slightly larger than the display, for example have a larger diameter than a diameter of the display. Since the housing is preferably mounted at a distance of the base of the air entrance, air can circulate alongside and behind the housing of the display. The same is true for any other mechanical element, other than a display, included in the housing, as mentioned above.

[17] Said distance between the housing and the base of the air entrance can preferably be chosen such that a narrowest passage of the air entrance is comprised in a range of more or less 7 mm to more or less 17 mm, more preferably around 11 mm. The narrowest passage can thus improve an increase of air speed while remaining large enough to allow sufficient air to be taken in spite of a substantially central blocking of at least part of an air intake by the housing of the display and/or by the display itself.

[18] A diameter of a base of the air entrance can preferably be comprised between more or less 35 mm to more or less 45 mm, more preferably between more or less 37 mm and more or less 43 mm, for example around substantially 41 mm. Such a diameter can be a compromise between a sufficient increase in pressure and a sufficient volume of air intake.

[19] The hair styling device can further generally comprise a fan configured to cause air to enter into the main body via the air entrance. Said fan may advantageously be positioned at a distance of a base of said air entrance, such that the distance between said fan and the base of the air entrance is comprised in a range between more or less 0.5 mm to more or less 20 mm, more preferably in a range of more or less 0.5 mm to more or less 2 mm, for example around more or less 1.75 mm. Said distance can optimize a volume of air intake and building up of pressure in front of the fan in a direction of air flow.

[20] When the hair styling device includes a central and substantially circular obstruction of the air entrance leaving a ring-shaped open portion, the air entrance can be preferably shaped as described above, i.e. including two substantially truncated conical portions connected by said flange, such that a diameter of a base of the air entrance is comprised between 35 mm - 45 mm, a height of the narrowest air passage is comprised between 7 mm - 17 mm. By judiciously combining dimensions of the air entrance, a relatively large volume of air flow at intake can be obtained in this way. [21] The hair styling device can include a data communication port configured to be connected to an external controller for exchanging data. The external controller can for example include a system on chip including computer program code. In this way, control code of an internal controller of the hair styling device can be updated in a relatively easy way. Moreover, data with respect to a use of the hair styling device can be read out and/or transferred to the external controller. Said data communication port can for example be integrated in the housing of the main body, in the handle, or, most preferably, in the display housing, or at any other suitable location. Since the wedge- shaped end piece can be detachably mountable to the back end of the main body, the data communication port can be protected while being easily accessible. At the same time, a printed circuit board may be present adjacent to the display and may be more easily accessible than a main internal controller, which can preferably at least partially be located in the handle.

[22] According to a further aspect of the invention, there is provided a hair styling device comprising at least one electronically driven element, an acceleration sensor configured to measure accelerations of the hair styling device in at least three directions, and a controller configured to determine a usage state of the hair styling device based on said accelerations in said three directions. Such a relatively reliable determination of a usage stage can allow implementation of different actions related to the determined usage state. This aspect can be considered as a separate invention and can be of particular advantage for a hairstyling device including a display. The at least one electronically driven element can for example be a heat generating element, but may also be one or more of a motor, for example driving a fan, a hot or cold vaporisation chamber, a display device, an indicator light, or alike.

[23] The hair styling device comprises an acceleration sensor or accelerometer that is attached or fixed to the hair styling device, in particular to the main body or to the handle of the device. The wording "attached" in this context means that the sensor is configured move together with the device to which it is attached and will therefore be able to detect and record any acceleration of the device itself. The sensor is preferably fixedly attached to the device at a location which is suitable for tracking the accelerations of the device. The acceleration sensor or accelerometer is advantageously positioned within the main body such that it senses the accelerations exerted on the main body. A preferable position for the accelerometer component is within the main body, but outside of the heated zone from the heat generating element, as the sensors may be sensitive to temperature changes, and may suffer damage when subjected to high temperatures. A preferable location for it is on an electronic printed circuit that is integrated close to the air inlet of the device. Alternatively, the acceleration sensor may be positioned in the handle of the device.

[24] The acceleration sensor of the invention is configured to measure the accelerations in at least three directions, in particular in three different directions such that the accelerations in three dimensions can be measured. The acceleration sensor is preferably configured to measure the accelerations in the three orthogonal directions.

[25] The controller of the invention may be an electronic controller or computer- based controller. Regardless of the actual implementation, the controller is configured to process an input of the acceleration sensor and is configured to determine a usage state of the hair styling device. Thereto, the controller is electronically connected to the acceleration sensor, and is configured to substantially continuously receive or read out the acceleration information on the three directions from the acceleration sensor. The signal provided by the acceleration sensor to the controller may be an analogue signal or a number of analogue signals but is preferably a digital signal comprising the acceleration information from the three directions. The signal of the acceleration sensor provides a measure for the acceleration of the sensor, and therefore of the hair styling device, to which it is attached.

[26] Said usage state can for example include an idle state in which the device is plugged but not in use, an operating state in which the device is in use, a falling state in which the device falls down or a fallen state in which the device has just fallen down, and thus stopped falling down. The idle state has to be understood as the state of the hair styling device when the device is plugged but not used or handled by the user. A motor and/or a heat generating element is not operating in the idle state. A display or an indicator light may, but need not, be operating in the idle state. The device may for instance not be held in the hands by the user in order to apply it to the hair which needs styling but may rather be placed on a surface or be stored. The operating state is the state in which the device is activated to perform a hair styling action. In this state the hair styling device may for example blow cold or heated air, or produce cold or hot vapour, or any other known hair styling action for application to the hair which needs styling. Acceleration conditions may further allow to determine other usage states, such as for example an unplugged state, a booting state, an energy-saving state or any other state not mentioned here. Determining a usage state of the device advantageously allows the determination, recording and logging of the usage state over time, such that for example usage patterns or statistics may be obtained.

[27] Different acceleration measurement patterns may be interpreted by the controller as belonging to a same usage state. But once a usage state is determined, the determination of said usage state can serve as a trigger to initiate a particular step or process, in particular a step or a process that changes the operating behaviour of one or more of the electrically driven elements.

[28] The controller may be configured to determine said usage state as being the operating state by substantially continuously detecting variations in the measured accelerations in at least one direction. The controller may be configured to substantially continuously analyse received acceleration measurements. Since a read-out frequency can determine a responsiveness of the system, the acceleration information may be read-out and processed at any predetermined frequency, preferably at a frequency between 0.01 Hz to 10kHz, and more preferably between 1 Hz up to 65Hz. In the context of this invention, the analysis of the incoming acceleration measurements should be performed at a frequency that allows a suitable responsiveness for determining the operating state. Substantially continuously means in the context of this invention that the measured variations in acceleration persist at least for certain period of time, for instance during at least one or two seconds before the usage state is set to the operating state. More specifically, the operating state can be determined upon detection of variations in the measured acceleration in at least one direction. For instance, as soon as the device is picked up by a user, a variation in the acceleration measurements will be detected, which may then determine the operating state of the device.

[29] Since an acceleration in a certain direction can be decomposed into three acceleration components in the three spatial dimensions, the representation of said acceleration in said three spatial dimensions may advantageously be represented as a vector. A vector has a scalar value and a direction. The controller may be configured to detect said usage state as a variation of the direction of a vector representation of said measured accelerations in at least one of said three orthogonal directions, or, alternatively, as a variation of the scalar value of a vector representation of said measured accelerations. Changes in acceleration direction can be represented as changes in angles between vectors. Changes in acceleration magnitude can be represented as changes in the scalars of the vectors.

[30] Said controller may be configured to detect said operating state when said variations of the direction of said vector representation of said measured accelerations in three directions exceed a predetermined threshold, which may for example be a minimum of more or less 10 degrees or any other threshold value. The measurement of a variation of minimally more or less 10 degrees between an initial angle and a measured angle may typically indicate that the device is picked up and is changed in orientation, for instance with the purpose to direct the air flow of the hair styling device towards hair to be styled. Since a variation or change of angles is measured, it means that a reference direction has to be selected that will be set off against the direction of the actually measured acceleration direction. The reference direction may be chosen in different ways, for instance as the direction of the acceleration vector at the moment when the idle state was identified, or as the direction of the acceleration vector of a last previous time interval. Additionally, and/or alternatively, the controller may be configured to detect said operating state based on a speed of a variation of an angle between said vector representation of said measured accelerations in three directions, i.e. a derivative of the angle in function of time, in particular to detect a picking up of the hair styling device.

[31] This approach has the advantage to define a very clear criterion on which the change of usage state to the operating state may be based. A sudden rotation of the device detected as a change in acceleration may be indicative of a transition to the operating state, whereas linear accelerations alone may not be indicative for a user starting to use the device. Linear acceleration may be caused by a shift or slide of the device on its resting surface or may be caused by vibrations without the intention of a user to start using the device.

[32] The controller can be configured to determine said usage state as being the idle state by detecting said variations of the direction of said vector representation of said measured accelerations in three directions being smaller than two degrees for a predetermined idle detection period of time. Similarly, as above, the idle state can be determined when the detected variations of the direction of the vector representation of the measured accelerations are smaller than two degrees for a predetermined idle detection period of time. So rather than defining the criteria to determine the idle state in terms of absolute accelerations in any of the three directions, a more robust determination may be based on detecting variations in the vector angles. Measurement of the absolute accelerations is more sensitive for unwanted small vibrations or shocks applied to the device, compared to measurement of variations of said vector representation of said measured accelerations in three directions. It is therefore one of the advantages of the invention that the determination of the operating state by means of the above principle is less sensitive to shocks or vibrations, and therefore less sensitive to unwanted triggers.

[33] Alternatively, the controller can be configured to determine said usage state as being the idle state when a total of the measured accelerations of the hair styling device substantially equals gravitational acceleration, for example during at least one second. In other words, instead of using a change in direction of a vector representation of an acceleration, the scalar magnitude or dimension of the acceleration is used to determine the usage state, which may simplify the algorithm. Values of the measured accelerations in the three directions may be stored, which values may indicate a position of the hair styling device while being in the idle state.

[34] The controller may be configured to detect said usage state as a falling state by determining that all accelerations are below a predefined threshold for a predetermined falling detection period of time. When a device such as the hair styling device of the invention is in a free fall, the device will experience no accelerations. Therefore, the measured accelerations in all three directions will drop below a certain threshold and will approach zero. Therefore, in the invention, a falling state can be reliably determined by applying these criteria. Additionally, and/or alternatively, the acceleration sensor itself may be configured to detect a falling state such that the controller only needs to be configured to read out the information provided by the acceleration sensor with respect to a falling state. [35] The above predetermined threshold may for example be less than 0.5 times g, preferably more or less 0.315 times g, g being acceleration due to gravity. By further specifying the criteria defining the falling state accordingly, the falling state can even be determined more reliably by the controller.

[36] Similarly, the predetermined falling detection period of time may be defined more narrowly as being at least 30 ms. Said controller may be configured to detect said usage state as the fallen state when the duration of a falling state exceeds for example 350ms, more preferably 200 ms. Applying this criterion allows a relatively reliable determination of the usage state as the fallen state.

[37] Alternatively, the acceleration sensor may include a dedicated pin configured to provide a high voltage signal to the controller when the sensor detects a fall. The controller may then be configured to determine a falling state when said voltage is high over a predetermined period of for example 200 milliseconds.

[38] The controller may also be configured to control the at least one electrically driven element in response to said determined usage state, in particular to changes in said determined usage state. The hairstyling device may include at least one of the following electronically driven components, which may be controlled in this way, the list not being exhaustive: a motor driving a fan, one or more heat generating elements, air ionizing components, a hot or cold vaporisation chamber, indicator lights, status indicators, display devices, or any other known electronically driven component. A professional hair dryer may for example comprise one or more heating elements, a motor mounted with a fan, and a digital display. Controlling one of said components can include bringing a component in a different operating state, in particular by activating or deactivating said component. An indicator light can for example be switched on or off but may also be controlled by changing a colour of the light produced, or by changing an intensity at which it emits light. Similarly, a heat generating element can be controlled by switching it on or off, but also by amending a dissipating power. A motor can for example be controlled by changing rotating speeds.

[39] This now allows to determine actions, which can be a single step or a sequence of steps, when the usage state of the hair styling device changes. As an example of such a sequence of steps, the determination of the falling or fallen state of the device may cause the sequence of switching the heat generating element off, incrementing the value a counter that stores the number of drops the device has suffered during its lifecycle, displaying an error state on a status LED by making it blink in for example a red colour, and turning off the motor of the fan, for example after two seconds. The possibilities to define sequences are endless and advantageously render the hair styling device more user friendly and intuitive.

[40] Depending on the type of hair styling device, a different electrically driven component will be operated upon. A hair straightener typically comprises heating plates as a heating element, which is the main active component of the device. However, a hair straightener may also comprise a display device and/or a number of indicators or status lights. Depending on the determined usage state different components may be activated or deactivated, may be switched on or off, or may be operated to display a certain message. A logical action that may defined for the idle state is for instance the deactivation of the heating plates, and a change of colour from green to red of a status light. Other types of devices may comprise different electronically driven components; a professional hair dryer will comprise for instance one or more heating elements, a motor mounted with a fan, a digital display device or alike.

[41] As an example of the above, the controlling of at least one electrically driven element can include for instance the activation of at least one electrically driven element in case the usage state is determined as the operational state. Similarly, a hair styling device may be provided wherein the controlling of at least one electrically driven element includes for instance the de-activation of said at least one electrically driven element in case the determined usage state is the idle state or the falling state. The latter actions can be envisaged as a safety feature of the device.

[42] It is therefore an advantage of the invention that well delineated situations or usage states may be used as triggers to initiate a step or a sequence of steps that changes the operating behaviour of one or more of the electrically driven elements. This approach allows for an improvement in user experience, since the activation, deactivation or operation of the electrically driven elements is managed by the determination of the usage state and not by user interface actions or manipulations, pressing buttons or switching levers. The user can therefore focus on the activity of hair styling rather than having to focus on the operation of the different active components of the hair styling device. The activation and deactivation of the hair styling device of the invention can be performed without explicit user intervention, which may be perceived as improvements to the ergonomics of the device or as a safety feature.

[43] The controller may be configured to count occurrences of said usage state, in particular of the fallen state. Counting the occurrences of transitions to a certain operating state may be useful to log, report or act upon a number of incidents. In particular, it may be useful to count the number of incidences where the device entered into a falling or fallen state. A detection of a high number of fallen states may trigger a request for a service revision of the device or alike. It may also be useful to count the time during which the device is in a certain usage state. Logging the time spent in the operating state may provide useful information about the anticipated wear and tear of the device. The usage statistics may provide for instance the number of running hours of the device, the number of idle hours, the number of drops of the device, or other states, which may for example be considered when evaluating a repair under warranty. The latter feature provides the advantage of the possibility to act upon usage data provided by the device.

[44] Said controller may further be configured to operate said device according to the determined usage state without user input. In the context of the invention, the device reacts upon changes in usage states determined by the controller of the device. This implies that no active user input is required to establish such a change in usage state, i.e., that no controls, buttons or interfaces on the device have to be pressed, activated or manipulated to establish the change in usage state. This provides clear advantages in respect of the useability and ergonomics of the device.

Brief Description of the Drawings

[45] Fig. 1 shows a side view on a preferred embodiment of a hair styling device according to an aspect of the invention;

[46] Fig. 2 shows a cross-sectional side view of the hair styling device shown in Figure 1 [47] Fig. 3 shows a side view on a partially opened main body of the hair styling device shown in Figure 1 ;

[48] Fig. 4 shows a perspective back view on the back end of the hair styling device of Figure 3;

[49] Fig. 5 shows a cross-sectional side view of the back end of the hair styling device shown in Figure 3;

[50] Fig. 6a and 6b show a perspective back view and perspective a cross-sectional view on the back end of the hair styling device without display;

[51] Fig. 7 shows a side view on the main body of the hair styling device of Figure 1 ;

[52] Fig. 8a, 8b and 8c show a perspective view, a back view and a cross-sectional side view on the wedge-shaped end piece of the hair styling device of Figure 1 ; and

[53] Fig. 9 shows a flowchart of a preferred embodiment of a method of controlling a hair styling device including at least one electronically driven element according to a further aspect of the invention.

Detailed Description of Embodiment(s)

[54] Figure 1 shows a side view on a preferred embodiment of a hair styling device 1 according to an aspect of the invention. The hair styling device 1 may be used for drying and/or styling someone’s hair, for example one’s own hair or, more preferably, a client’s hair, for example by a professional hairdresser in a hairdressing salon or in any other setting. The hair styling device comprises a main body 2 having a back end 3, which may include an air entrance 4, and a front end 5 including an air exit 6. The front end 5 may be further configured to receive mountable accessories, for example to change a shape of the air exit 6 to adapt an air flow to a type of hair or to a desired type of styling, as is known to the person skilled in the art. The main body 2 is configured to guide air from the air entrance 4 to the air exit 6. The main body 2 can include a housing 7 at least partially enclosing for example a fan, a motor block and/or heating elements. Said housing 7 may for example include a thickening or a protrusion 7a where a width of the housing is maximal. Said protrusion 7a can provide additional strength and/or protection to the housing 7 on the portion which is in contact with a surface when the hair styling device is laid down sideways on said surface. The hair styling device 1 further comprises a handle 8 attached to the main body 2 and configured to hold the hair styling device 1 by hand. The handle 8 can for example be mounted substantially transversely to the main body 2. The handle 8, in particular an upper end 8u of the handle 8, may preferably be fixedly attached to the main body. Alternatively, the handle 8 may be tiltable or foldable with respect to the main body 2, for example to allow compact storing of the hair styling device 1 . Other embodiments of hair styling devices may not necessarily include a handle separate from the main body, or the handle and the main body may be in line with each other. The main body 1 , as well as the handle 8, can allow to define a longitudinal axis 2a of the main body 2 and a longitudinal axis 8a of the handle 8. Said two longitudinal directions 2a, 8a are included in a plane defining two lateral sides of the hair styling device 1 . The hair styling device 1 may further include a power supply cable 9. Said power supply cable 9 can for example be connected to a lower end 8I of the handle at a distance of the main body 2. The power supply cable 9 may be fixedly attached to the handle 8, or in a rotatable or swivelling manner, and/ or in a detachable way. The power supply cable 9 may preferably be attached using a strain relief device to prevent damaging an electric connection when the hair styling device 1 is hanging on the power supply cable 9, which might be dangerous for the user of the hair styling device 1 . Alternatively, the power supply cable may be connected or connectable to the hair styling device at any other suitable location. Alternatively, the hair styling device may be chargeable at a remote charging station, thus being operable without connected power cable.

[55] Figure 2 shows a cross-sectional side view of the hair styling device shown in Figure 1 . The housing 7 can for example enclose a fan 10 configured to cause air to be sucked in via the air entrance 4. The housing can further enclose a motor block 11 configured to cause the fan 10 to rotate. The housing 7 can include a narrowing 12, for example a substantially conical narrowing, towards an air exit 6. The housing 7, in particular said narrowing portion 12, can enclose one or more heating elements 13 configured to heat air such that the air exiting the main body 2 has a desired temperature which is higher than an air temperature at the air entrance 4. The hair styling device can further include a control element 14 or a main internal controller, for example one or more PCB's, configured to control an operation of the hair styling device 1. Said control element 14 may for example be located at least partially in the handle 8 of the hair styling device 1 . The device 1 may include an additional motor control element 15 configured to control operation of the motor, which motor control element may be positioned adjacent to said motor block 11 in the main body 2 of the hair styling device 1 .

[56] Figure 3 shows a side view on the partially opened main body 2 of the hair styling device 1 shown in Figure 1 . In particular, the back end 3 of the hair styling device 1 is shown in an open way. The hair styling device 1 includes a display 16 positioned at the back end 3 of the main body 2. In an inventive way, the display 16 is tilted with respect to a plane 17 substantially transverse to a longitudinal axis 2a of the main body 2. The display 16 may for example be tilted over a tilt angle 18 comprised between more or less 5° to more or less 20°, preferably over a tilt angle 18 between more or less 8° to more or less 15°, most preferably over a tilt angle 18 of around 10°. The tilt angle 18 can be oriented such that a lower side of said display 16 is offset from said plane 17 substantially transverse to said longitudinal axis 2a of the main body 2. “Upper” and “lower” can be defined with respect to a longitudinal axis of the handle, the lower end 8I of the handle being the portion of the handle 8 at a distance of the main body 2. The lower side of the display 16 can thus be defined as the portion of the display which is closest to the handle 8. Said tilt angle 18, as well as said orientation of the tilt angle 16, can preferably be fixed. Alternatively, the tilt angle 18, as well as said orientation of the tilt angle 16, may be adjustable.

[57] Figure 4 shows a perspective back view on the main body of the hair styling device of Figure 1 . The display 16 can preferably be mounted on a dedicated housing 19, the display housing 19 being attached to the housing 2 of the main body, for example via a plurality of connection struts 20. The dedicated display housing 19 can preferably protrude backwardly from the housing 2 and be positioned at a distance of said housing 2, as shown also in Figure 3. Since the display 16 is positioned at the back end 3 of the hair styling device 1 , which can also include the air entrance 4, the display 16 can be positioned substantially centrally in front of the air entrance 4 partially blocking air intake centrally. The display 16 can preferably have a substantially circular shape, in particular when the main body 2 is substantially cylindrical or at least partially conical orfrustoconical. A diameter of said substantially circular display 16 is preferably smaller than a diameter of the back end 3 of the hair styling device 1 . An outer diameter of the back end 3 may for example be comprised between more or less 80 mm and 85 mm, being for example more or less 81 .5 mm while an inner diameter of the back end 3 may for example be included in a range of 70 mm to more or less 75 mm, being for example around 72.5 mm. A diameter of the display housing 19 may then be comprised in a range of more or less 42 mm to more or less 50 mm, being for example 46 mm. A diameter of the display 16 can then be slightly smaller than a diameter of the display housing 19. A viewing angle, in particular a lateral or horizontal viewing angle, of the display 16 can advantageously be higher than 159°, preferably higher than 169°, which may for example be obtained with by using a liquid-crystal display (LCD), for example a thin-film-transistor liquid-crystal display (TFT), or an organic light-emitting diode display (OLED), or any other suitable monitor technology. The horizontal viewing angle can be defined as the viewing angle in a plane which is substantially transverse to the longitudinal axis 8a of the handle 8. The display 16 can be configured to display functional parameters of the hair styling device, such as for example a temperature of the outcoming air, a chosen volume of air flow, a duration of use, a cumulative duration of use, an instantaneous energy consumption of the hair styling device, a cumulative energy consumption of the hair styling device, and other potentially relevant parameters. In absence of a display, or in addition to the display, actual predetermined settings of temperature and air flow can also be visualized with the aid of lights 37, for example a plurality of LED-lights, which may for example be positioned at a back of the handle 8, or at any other suitable location. The hair styling device 1 can further include a data communication port 36 configured to connect the hair styling device 1 to an external controller for exchanging data. The external controller can for example include a system on chip including computer program code. In this way, control code of the hair styling device can be updated in a relatively easy way, even in a hairdresser’s salon. Moreover, data with respect to a use of the hair styling device can be read out and/or transferred to the external controller. Said data communication port 36 can for example be integrated in the display housing 19.

[58] Figure 5 shows a cross-sectional side view of the back end 3 of the hair styling device 1 shown in Figure 3. The dedicated display housing 19 can for example be releasably attached to the housing 7 of the main body 2, for example via a snap connection 21 at an end of one or more of the struts 20. Since the display 16 may be positioned substantially centrally, but at a distance of, the air entrance 4, a shape of the air entrance 4 may be adapted to optimize air intake in spite of this partial blocking of the central air intake due to the presence of the display 16 and/or the dedicated housing 19. In an inventive way, the air entrance 4 can include two substantially truncated conical portions 22, 23 connected by a flange 24. In particular, a first substantially truncated conical portion 23 can provide a relatively large air intake, whereas the flange 24 can connect the first substantially truncated conical to the second substantially truncated conical portion 23. In this way, a higher volume of air can be taken in than if there were only a single truncated conical portion connecting a relatively large outside diameter to the minimal inner diameter. This is also valid when no display is present in the dedicated housing, for example when the dedicated housing includes for example a mirror, a picture, a watch, a logo, or any other element blocking the air intake substantially centrally. The shape of the air entrance as described can thus be regarded as a separate invention, which is independent of the presence of the display. An end in the direction of air flow of the second substantially truncated conical portion can then be considered as a base of the air entrance 25. A diameter of said base of the air entrance 25 can for example be comprised between more or less 37 mm to more or less 48 mm. To further maximize a volume of air intake for a given display housing 19 diameter and a given diameter of the housing 7 of the main body 2, leaving for example a radial distance 26 of between more or less 13 mm to 14 mm between the display housing 19 and an edge of the housing 7, a narrowest air passage 27 may be comprised in a range of more or less 5 mm to more or less 15 mm, said narrowest air passage being measured in a longitudinal direction 2a of the main body 2 between the flange 24 and an inner side of the display housing 19, the inner side facing the fan 10 of the hair styling device 1 .

[59] Figures 6a and 6b show a perspective back view and a perspective cross- sectional view on the back end 3 of the hair styling device 1 in which the dedicated housing 19 has been taken off such that there is a free view on the air entrance 4. The fan 10 is configured to cause air to enter into the main body 2 via the air entrance 4. It has been shown that a judicious adjustment of the position of the fan with respect to the base 25 of the air entrance can further optimize a volume of air intake. Said fan 10 can preferably be positioned at a distance of the base 25 of said air entrance 4 between 0.5 and 20 mm, more preferably between 0.5 mm and 10 mm, most preferably at a distance of more or less 1 .75 mm. As a result, a distance 28 between said fan and the flange 24 may preferably be comprised in a range between more or less 2 mm to more or less 12 mm, being for example 6.5 mm, 5 mm, 4 mm, 8 mm, 6 mm, 10 mm or any other value of said range. For a central and substantially circular obstruction of the air entrance 4 at the back end of a hair styling device having back end dimensions as described with respect to Figure 4, the remaining ring-shaped open portion or air entrance 4 can have a radial width 26 of more or less 13.25 mm, such that a relatively large volume of air flow at intake can be obtained by judiciously combining dimensions of the air entrance 4 including a diameter of a base of the air entrance 25 and a height of the narrowest air passage 27. In the Table underneath, examples of potential combinations of parameters are given:

[60] Figure 7 shows a side view on the main body of the hair styling device of Figure 1 . The hair styling device, in particular the back end 3 the main body 2, can further comprise a wedge-shaped end piece 29. Said wedge-shaped end piece can be releasably mountable to the back end 3 of the main body 2, for example via a snap connection 30, shown in Figures 5 or 6b. Any other suitable connection may be used as well. An angle 31 of the wedge-shaped end piece 29 can preferably be substantially equal to the tilt angle 18 of the display 16 with respect to the plane 17 substantially transverse to said longitudinal axis 2a of the main body 2, in particular comprised in a range of more or less 5° to more or less 20°. In this way, the display can be substantially flush with said wedge-shaped end piece 29. Alternatively, the angle of the wedge- shaped end piece 29 may also be a different angle, such that the display 16 is recessed in said end piece or protrudes from said end piece 29. The wedge-shape end piece 29 may include a central through-hole 32 such that the display 16 can remain visible. Alternatively, the wedge-shaped end piece 29 may include a central closure, for example a releasable closure, such that a display or any other central element, such as a mirror or a logo, can be closed off, for example to protect said central element. Said central closure may for example be a substantially transparent closure such that a display or other element underneath can remain visible.

[61] Figures 8a, 8b and 8c show a perspective view, a back view and a cross- sectional side view respectively on the wedge-shaped end piece 29 of the hair styling device 1 of Figure 1. Said end piece 29 can advantageously include a filter 33 configured to filter incoming air. Said filter 33 can preferably be a ring-shaped filter, preferably enclosing said central through-hole 32 or central closure. To ensure sufficient air intake, said filter can have a ratio of open surface to closed surface of more or less 40% to more or less 80%, preferably around more or less 50%, which can provide a balance between air intake and filtering. Open surface of the filter can be provided by a plurality of holes 34, for example substantially circular holes, or holes of any other suitable shape. Said individual holes are dimensioned such that impurities, in particular dust particles, in the air can be prevented from entering the hair styling device 1 . The holes 34 may for example be arranged in concentric circles, for example in four concentric circles enclosing said through-hole 32 or other central element, including a same number of holes per circle, implying that a diameter of each hole decreases from the outermost circle to the innermost circle, as show in Figure 8b. Other arrangements of holes can be feasible as well, as long as a ratio of open surface to closed surface can be maximised while keeping individual holes small enough to have a filtering operation of incoming air. To further maximize a surface area of the ring-shaped filter, the filter 33 can be substantially concave. A deepest point 35 of the concave shape in cross-section can preferably lie substantially halfway radially of the ring-shaped filter. Other cross-sectional shapes of the filter 33 can be possible as well. A second filter, for example a filter mesh, can be provided on an inner side of the end piece 29. In this way, the holes 34 may filter relatively large particles, for example larger than more or less 1 .2 mm, while the second filter can be configured to filter relatively small particles, for example smaller than more or less 1 .2 mm. Other dimensions are of course feasible as well. A shape of the holes in the second filter may also be different from a shape of the holes 34 of the ring-shaped filter.

[62] Figure 9 shows a flowchart of a preferred embodiment of a method of controlling a hair styling device including at least one electronically driven element according to a further aspect of the invention. The hair styling device may for example be a professional hairdryer as described with respect to the preceding figures, or any other type of hair styling device, such as a travel hair dryer or a hair straightener, including at least one electronically controlled element, such as a motor, a heat generating element, a hot or cold vaporisation chamber, a display, an indicator light, or alike. Hair styling devices may comprise electronic circuits, which include a microcontroller or control board which may be configured to process input, for example from switches and/or buttons, and control the heat generating element and fan motor accordingly. The microcontroller may be configured to interpret the user's selections and adjust the temperature and airflow speed accordingly. In a first step 100, the controller receives data from an acceleration sensor included in the hair styling device. The acceleration sensor may be an electronic component which is preferably implemented as a Micro Electro-Mechanical System (MEMS). MEMS devices are cost-effective, have a small footprint and can be easily implemented in an electronic circuit. An accelerometer or acceleration sensor is configured to measure linear acceleration along one or more axes, preferably along three orthogonal axes. The sensor may for example include a small mass suspended on flexible beams. When the accelerometer experiences acceleration, the mass moves relative to the surrounding structure, and this displacement is measured to determine the acceleration. The principle behind the accelerometer's operation is based on the relationship between force and mass, F=ma. When the device undergoes acceleration, the mass inside it experiences a force, causing it to move relative to the sensor's frame. The displacement is converted into an electrical signal, which is then processed to calculate the acceleration.

[63] Alternatively, the sensor may be a gyroscope. The difference between an accelerometer and a gyroscope is that an accelerometer measures linear acceleration, specified in mV/g, along one or several axes, whereas a gyroscope measures angular velocity, specified in mV/deg/s. An accelerometer will not respond to a pure rotation. Consequently, the accelerometer’s output will not respond to change in angular velocity. Similarly, a gyroscope will only respond to a change in angular velocity, but not to a linear acceleration. A MEMS gyroscope sensor is a micro-machined inertial device that can measure the angle of orientation or the angular rate of rotation. The principle relies on a vibrating structure that is suspended in a way that Coriolis forces can be sensed as the mass undergoes a rotation relative to the inertial space. It is a device that measures angular velocity or the rate of rotation around one or more axes. It typically includes a small vibrating structure, often a tiny tuning fork or a vibratory ring, which oscillates in response to rotation. When the gyroscope experiences angular motion, the Coriolis effect causes the vibrating structure to deflect, and this deflection is measured to determine the rotation rate. A gyroscope is configured to measure rotational motion but is not suitable for measuring linear acceleration. They are sensitive to environmental factors like temperature changes and vibrations, which can introduce noise and errors in the measurements. Gyroscopes have a phenomenon called "gyro drift," where the output may deviate over time due to manufacturing imperfections and other factors. This drift can affect the accuracy of long-term measurements.

[64] In step 110, data received from the acceleration sensor including accelerations along each of the three orthogonal axes, are being processed, for example filtered by a low pass filter, and a scalar dimension or vector size is determined, which may again be filtered by a low pass filter. Step 120 indicates that the measurements and processing of the received data is repeated at a relatively high frequency, for example at 60 Hz or every 16 milliseconds or any other predetermined frequency. Said frequency may advantageously correspond to a refresh rate of a display 16.

[65] In a next step, the obtained dimension of acceleration is compared to earth acceleration G. If in step 130 the determined acceleration is smaller than 1.1 G and larger than 0.9 G and this during at least 1 second, then the measured accelerations along each of the three axes will be stored in step 140 to store an orientation of the hair styling device. These accelerations indicate that the hair styling device is in an idle state, for example lying down, so the controller may then be configured to initiate for example a screen saver mode 150, of which light can for example be dimmed to limit energy consumption. If the determined acceleration is larger than 1.1 G or smaller than 0.9 G in step 160, then the controller may be configured to wait for a predetermined period of time in step 170, for example 500 milliseconds or any other time period and then compare the stored acceleration data of step 140 with the most recently measured acceleration data of step 110. If there is a difference in one of the accelerations of for example at least 0.1 , meaning that the hair styling device has really changed position and not just been pushed aside, then in step 180 the controller may be configured to pass from a screen saving mode to still an idle but awakened state, in which a screen is activated and ready to receive user input on a desired temperature and/or flow rate. A motor and/or a heating element of the hair styling device are still deactivated.

[66] In a more preferred embodiment, the controller may even be configured to perform the transition from an idle state to an operating state or vice versa, so start/stop a motor driving a fan and/or start/stop the heat generating element based on said acceleration data. Alternatively, the motor may be started automatically after receiving a user input on a required flow rate. In both cases, the hair styling device may be free from, and does not need, any power on-off switch, as known from prior art devices. As soon as the hair styling is plugged into the mains, and after a short fault check and boot mode, the hair styling device is in an idle but awakened state, in which the user can choose a desired air flow rate and/or a desired air temperature, which may be indicated on a display 32 and selected for example via two selection buttons in a recess at the back of the handle 8 or directly on the display if the display is a touch screen. The selection of an airflow rate may at the same time cause the motor to start operating the fan, whereas a temperature selection only can preferably not cause the heat generating element to start operating for safety reasons except if the motor has already been started.

[67] In case of a fall, detected by the acceleration sensor and communicated to the controller, the hair styling device may be configured to switch to an idle state, preferably an idle and awakened state, either from the operating state by switching off the heat generating element and the motor, or from the idle screen-saving mode, or remain in the idle and awakened mode, while adding in any of these cases a fall to a fall counter.

[68] Although the present invention has been illustrated by reference to specific embodiments, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied with various changes and modifications without departing from the scope thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. In other words, it is contemplated to cover any and all modifications, variations or equivalents that fall within the scope of the basic underlying principles and whose essential attributes are claimed in this patent application. It will furthermore be understood by the reader of this patent application that the words "comprising" or "comprise" do not exclude other elements or steps, that the words "a" or "an" do not exclude a plurality, and that a single element, such as a computer system, a processor, or another integrated unit may fulfil the functions of several means recited in the claims. Any reference signs in the claims shall not be construed as limiting the respective claims concerned. The terms "first", "second", third", "a", "b", "c", and the like, when used in the description or in the claims are introduced to distinguish between similar elements or steps and are not necessarily describing a sequential or chronological order. Similarly, the terms "top", "bottom", "over", "under", and the like are introduced for descriptive purposes and not necessarily to denote relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and embodiments of the invention are capable of operating according to the present invention in other sequences, or in orientations different from the one(s) described or illustrated above.

Claims

1 . Hair styling device comprising

- a main body having a back end and a front end, the front end including an air exit, wherein the main body is configured to guide air from an air entrance to the air exit;

- a handle attached to the main body; wherein the hair styling device includes a display positioned at the back end of the main body, wherein the display is tilted with respect to a plane substantially transverse to a longitudinal axis of the main body.

2. Hair styling device according to claim 1 , wherein the display is tilted over a tilt angle comprised between more or less 5° to more or less 20°.

3. Hair styling device according to any of the preceding claims, wherein a lower side of said display is offset from said plane substantially transverse to said longitudinal axis of the main body.

4. Hair styling device according to any of the preceding claims, wherein a viewing angle of the display is higher than 159°, preferably higher than 169°.

5. Hair styling device according to any of the preceding claims, wherein the display is a substantially circular display.

6. Hair styling device according to any of the preceding claims, the main body further comprising a wedge-shaped end piece.

7. Hair styling device according to claim 6, wherein an angle of the wedge-shaped end piece is substantially equal to a tilt angle of the display with respect to the plane substantially transverse to said longitudinal axis of the main body.

8. Hair styling device according to any of the preceding claims, wherein the back end of the main body includes the air entrance.

9. Hair styling device according to any of the preceding claims 6- 7 and to claim

8, wherein said end piece includes a filter configured to filter incoming air.

10. Hair styling device according to any of the preceding claims 8 - 9, wherein the display is positioned substantially centrally in front of the air entrance partially blocking air intake.

11 . Hair styling device according to any of the preceding claims 8 - 10, wherein the air entrance includes two substantially truncated conical portions connected by a flange.

12. Hair styling device according to any of the preceding claims 8 - 11 , wherein the display is included in a housing, the housing being positioned at a distance of a base of the air entrance.

13. Hair styling device according to claim 12, wherein said distance is such that a narrowest air passage of the air entrance is comprised in a range of more or less 7 mm to more or less 17 mm.

14. Hair styling device according to any of the preceding claims 8 - 13, wherein a diameter of a base of the air entrance is comprised between more or less 35 mm to more or less 45 mm.

15. Hair styling device according to any of the preceding claims 8 - 14, wherein the hair styling device further comprises a fan configured to cause air to enter into the main body via the air entrance, wherein said fan is positioned at a distance of a base of said air entrance, said distance being comprised in a range between more or less 0.5 mm to more or less 12 mm, preferably in a range between more or less 0.5 mm to more or less 5 mm.