EP2622986B1 - Electric hair straightener - Google Patents

Description

Background of the invention

Embodiments relate to an electric hair straightener, which is often referred to as Straightener.

State of the art

Hair straighteners, which are often referred to as Straightener, are well known and serve, as the name suggests, for smoothing, for example, wavy hair. The smoothness effect is achieved, inter alia, by heating the hair, wherein the heating is caused by one or more heat sources.

Many hair straighteners are based on a pliers-like construction, which has two pivotally mounted arms. In at least one, often in both arms of the hair straightener then an electric heating plate is integrated, which serves as the aforementioned heat source. A large part of today used Haarglätterheizplatten here consists of a continuous casting, in which a heater, such as a ceramic heater or a PTC thermistor (PTC = Positive Temperature Coefficient) is pressed. The material of the continuous casting profile here is usually an aluminum alloy, which has a high thermal conductivity, which depends on the exact alloy composition.

For various reasons, for example, based on the reliability, optical and design technical but also other technical considerations, there is a tendency to use electrical heating plates, which are based for example on a glass, a ceramic or a glass ceramic.

Electric hair straighteners typically further comprise an electrical circuit, for example, for controlling or for supplying energy to the heating plate or the Serve heating plates. These are typically arranged outside of the heating plates, so spaced therefrom and connected via an electrical supply line with the one or more electric heating plates. The contacting of the electrical leads with the heating plates moves here in a field of tension, which is determined on the one hand from manufacturing costs, mechanical stability, reliability, overall visual impression and other boundary conditions.

From the DE 10 2007 002879 A1 a hair straightener with a heating plate is known which consists of several layers. The layers are joined together by pressure lamination. On one of these layers, a resistance heater is applied by screen printing before the pressure lamination. The resistance heater includes terminals to which cables are soldered.

From the DE 60200 4013 162T A is a hair care device, in particular a hair straightener with at least one heated plate known, which has a printed on it heating element. The plate consists of ceramic material. Terminal contacts are provided as part of the printed heating element to allow electrical connection to the heating element.

From the EP 0 218 797 A2 For example, a styling bar for effecting a curling state of hair strands is known which comprises a flexible and preferably flexible resistance heating element.

The problem underlying the invention

There is therefore a need to provide an electrical connection between an electrical heating plate and an electrical heating plate arranged outside of the electrical circuit and to facilitate assembly and thus manufacture of the electric hair straightener.

Inventive solution

This requirement is borne by an electric hair straightener according to claim 1.

It is already explicitly stated here that the reference signs contained in all claims should not and may not be used for a restrictive interpretation of the wording of the claims. Its implicit reference to specific embodiments of the subject matters and methods defined in the claims is only intended to facilitate understanding of the scope of protection as defined by the language of the claims.

An embodiment of an electric hair straightener comprises an electric heating plate having a substantially two-dimensional electrical resistance structure. The hair straightener further comprises an electrical circuit arranged outside the heating plate and a first electrical contact structure and a second electrical contact structure different from the first contact structure, which are arranged on the heating plate and provide an electrically conductive connection of the resistance structure with the electrical circuit via an electrical supply line.

An embodiment of an electric hair straightener is based on the finding that by providing the first and the second electrical contact structure, an electrical connection between the electric heating plate and the electrical circuit arranged outside the electric heating plate can be created. Embodiments thus relate to an electrical contacting of two-dimensional radiators on heating plates of hair straighteners.

The electrical circuit, which is arranged outside the heating plate, in this case does not necessarily represent a complete electrical circuit. Rather, it may, if appropriate, comprise only individual, possibly even only a single component of an electrical circuit. For example, the electrical circuit can comprise an electrical switch, a display element, that is to say for example a light-emitting diode or a potentiometer, or, if appropriate, also consist entirely of the abovementioned components. Of course, regardless of their size and the number of their components, the electrical circuit can be connected to one or more other electrical circuits or components in addition to the electrical heating plate. For example, the circuit may be connected to an electrical supply line which is provided with a mains plug and via which the electric hair straightener can be supplied with electrical energy.

Advantageous embodiments and developments, which can be used individually or in combination with each other, are the subject of the dependent claims. The reference numerals in the claims have no limiting effect but are merely intended to improve their readability.

In an electric hair straightener according to an embodiment, the first and / or the second electrical contact structure can provide the electrical connection via the supply line with the resistance structure such that the supply line extends beyond a plane defined by the resistance structure. In other words, a plane is defined by the substantially two-dimensional implementation of the resistance structure. As a result of the fact that the circuit is arranged outside the heating plate, the electrical connection to the circuit can now be created in such a way by the first and / or the second electrical contact structure that the electrical supply line no longer runs in the relevant plane, but leaves it , The electrical supply line For example, it may include a wire, a leaf spring, or another electrically conductive structure that is at least partially in the third dimension as compared to the two-dimensional electrical structure. The provision of the first and / or the second electrical contact structure can thus enable a more flexible interconnection of the contact structures with the circuit, since the circuit can be positioned more freely on or in the electric hair straightener.

In an electric hair straightener according to an embodiment, the first and / or the second contact structure may comprise a soldering and / or an electrically conductive bonding of the supply line to the resistance structure. In addition to the electrical connection, the first and / or the second contact structure can thus also provide a mechanical connection of the electrical supply line to the electrical heating plate. This can, for example, allow a certain mechanical displacement of the electric heating plate in the interior of the electric hair straightener with a suitable design of the electrical supply line, without the electrical connection between the supply line and resistor structure is interrupted. As a result, mechanical stresses, for example vibrations or a mechanical force during operation on the electric heating plate can be compensated if necessary. The soldering can be done here, for example, using classical solders, but possibly also with materials that are used in the context of the heating plate and / or the electrical contact structure. An electrically conductive bond can be carried out, for example, based on one-, two- or multi-component synthetic resins or solvent-based or solvent-free paints, which an electrically conductive filler, for example silver, gold, carbon, copper, tin, nickel, platinum, palladium or bronze admixed or added is. The soldering and / or the electrically conductive bonding thus creates an at least partially cohesive and at the same time electrically conductive connection between the supply line and the electrical resistance structure.

This is a frictional or frictional connection by stiction, a cohesive connection by molecular or atomic interactions and forces and a positive connection by a geometric connection of the respective connection partners come about. The static friction thus presupposes in particular a normal force component between the two connection partners.

In an electric hair straightener, the first and / or the second contact structure according to the invention comprises an electrical spring contact which is electrically connected to the supply line. The resistor structure includes a contact surface electrically connected thereto, the spring contact causing a force and being in contact with the contact surface by the force so as to provide electrical connection to the resistor structure. As a result, an assembly and thus a production of the electric hair straightener is simplified, since the electric heating plate can be manufactured separately and integrated into the electric hair straightener, wherein in the assembly via the spring contacts and their interaction with the contact surface of the resistor structure in assembling the electric hair straightener electric Connection between the feed line and the resistor structure can be created. A separate mechanical connection of the same can thereby be optionally saved.

In such an electric hair straightener according to an embodiment, the spring contact may comprise a leaf spring and / or a spring contact pin. A spring contact pin may in this case comprise, for example, a spring element and a contact surface electrically connected to the supply line, which is designed to be brought into contact with the contact surface of the resistance structure. The contact surface can be formed, for example, by an electrically conductive sleeve which at least partially surrounds the spring element. As a result, an optionally mechanically simple and yet resilient electrical connection can be created.

In an electric hair straightener according to an embodiment, the heating plate may comprise at least one mechanical attachment structure configured to mechanically connect with a mechanical connection element of the first and / or second contact structure. The connecting element can in this case be mechanically connected to the supply line and at least partially configured to be electrically conductive in order to create the electrical connection to the resistance structure with the resistance structure. As a result, the first and / or the second contact structure again not only to create the electrical connection, but possibly also to create a mechanical connection between the Supply line and the resistance structure of the heating plate are used. By using a mechanical fastening structure in the context of the heating plate and a corresponding connecting element in the context of the first and / or the second contact structure may thereby optionally be provided an easier-to-manufacture mechanical and electrical connection, so that the production of electric hair straightener can optionally be simplified. Alternatively or additionally, it may also be possible to design the mechanical connection in a detachable manner.

In such an electric hair straightener according to an embodiment, the attachment structure may comprise a recess in the heating plate, for example a blind hole, a bore, a threaded blind hole and / or a threaded bore and / or a projection, for example a pin and / or a threaded pin. In such a case, the connecting element may comprise an electrically contactable connecting element, for example a screw connection, a clamping element and / or a sleeve. As a result of these refinements, it is possible, if appropriate, to create a mechanically stable and / or mechanically loadable connection via the first and / or the second contact structure using structurally simple means.

In an electric hair straightener according to an exemplary embodiment, the resistance structure may comprise an electrically conductive, two-dimensionally structured resistance layer. Especially in such embodiments of a resistance structure, the electrical connection can be efficiently implemented by means of the first and the second contact structure.

In such an electric hair straightener according to an embodiment, the resistive layer may include or consist of tin oxide, zinc oxide, doped tin oxide, doped zinc oxide, graphite, graphene and / or carbon nanotubes (CNT). In such an electric hair straightener according to an embodiment, a layer thickness of the resistive layer may be at most 100 μm. In other embodiments, it may be at most 50 μm, at most 20 μm, at most 10 μm, at most 5 μm, at most 3 μm, at most 1000 nm, at most 500 nm, at most 300 nm, at most 200 nm, at most 100 nm, or at most 50 nm. The exact layer thickness can in this case of the used Material, the intended heating power, the available electrical voltage, the geometry of the resistor structure and other parameters. In other embodiments, however, larger thicknesses than 100 .mu.m may also be used.

In an electric hair straightener according to an embodiment, in which the resistance structure comprises an electrically conductive, two-dimensionally structured resistance layer, the resistance structure can at least one location, at which the first and / or the second contact structure causes the electrical connection to the resistance structure, a direct on comprise the resistor layer applied further resistive layer. The further resistance layer can thus be used as a contact surface or contact layer, in order to allow easier and / or improved contacting of the resistance layer.

In such an electric hair straightener according to an embodiment, the further resistive layer may have a lower electrical resistance in a plane defined by the resistive structure than an equally large area of the resistive layer. As a result, it may be possible to use the further resistance layer to achieve a better distribution of an electrical current fed or drawn off via the first and / or second contact structure. Thus, an improved distribution of the current flow can be achieved by connecting the further resistance layer in parallel through the further resistance layer at least at these locations. The further resistance layer may in this case be interrupted between the locations at which the first and the second contact structure brings about the electrical connection to the resistance structure, so that the resistance layer is not completely short-circuited by the further resistance layer.

In an electric hair straightener according to an embodiment, the heating plate may include an electrically insulating substrate, for example, a ceramic substrate, a glass-ceramic substrate, a glass substrate, or a quartz glass substrate having a main surface, and the resistance structure is directly applied to the main surface. Here, a substrate is understood to mean a volume-like material which enables a mechanical stabilization of the resistance structure. Defining boundaries is therefore the substrate in particular of a coating or a thin layer, such as may comprise the resistance structure, for example. As a result, an optically pleasing, possibly mechanically stable and / or safety-relevant implementation of an electric hair straightener may possibly be possible.

In such an electric hair straightener according to an embodiment, the main surface of the substrate may constitute a main surface of the heating plate. The resistance structure can thus be applied directly to the main surface of the heating plate or of the substrate. As a result, a production of the hair straightener can optionally be simplified.

However, in one embodiment, the major surface of the substrate may independently extend parallel to the above-defined plane defined by the substantially two-dimensional resistance structure.

In an electric hair straightener according to an embodiment, the resistor structure may include at least three first resistor sections extending in parallel, each of which directly electrically connects two first resistor sections through a second resistor section, the second resistor sections being connected to the first resistor sections at an angle other than 0 ° , The first resistor sections can optionally be designed to be rectilinear or curved. Additionally or alternatively, the resistance structure may also comprise a spiral resistance section. The resistance structure can thus be configured to be at least partially meander-shaped and / or spiral-shaped on the basis of an angular or a round shape. In this way, if appropriate, a particularly efficient distribution of the heat-producing resistance sections on the surface of the heating element can be produced, which may be advantageous especially for substrates with a non-optimal thermal conductivity.

In an electric hair straightener according to an embodiment, the electrical lead to the first and / or the second contact structure may comprise a wire or a leaf spring.

Exemplary embodiments of an electric hair straightener can thus make possible, with simple structural and cost-effective means, an easier and / or more resistant connection of an electrical connection between a substantially two-dimensional electrical resistance structure of an electrical heating plate and an electrical circuit arranged outside the same. If appropriate, this can be visually pleasing and / or robust.

Brief description of the drawings

Further advantageous embodiments will be described in more detail below with reference to an embodiment shown in the drawing, to which the invention is not limited.

• Fig. 1 zeigt eine schematische Darstellung eines elektrischen Haarglätters gemäß einem Ausführungsbeispiel;
• Fig. 2 zeigt eine mäanderförmige Ausgestaltung einer elektrischen Widerstandsstruktur einer elektrischen Heizplatte eines elektrischen Haarglätters gemäß einem Ausführungsbeispiel;
• Fig. 3 zeigt eine spiralförmige Ausgestaltung einer elektrischen Widerstandsstruktur einer elektrischen Heizplatte eines elektrischen Haarglätters gemäß einem Ausführungsbeispiel;
• Fig. 4 zeigt eine Querschnittsdarstellung einer elektrischen Heizplatte eines elektrischen Haarglätters gemäß einem Ausführungsbeispiel ohne eine elektrische Kontaktstruktur;
• Fig. 5 zeigt eine Querschnittsdarstellung einer elektrischen Heizplatte und einer auf einer Verlötung basierenden elektrischen Kontaktstruktur;
• Fig. 6 zeigt eine Querschnittsdarstellung einer elektrischen Heizplatte mit einer auf einem Federkontakt beruhenden elektrischen Kontaktstruktur gemäß einem Ausführungsbeispiel; und
• Fig. 7 zeigt eine Querschnittsdarstellung einer elektrischen Heizplatte und einer elektrischen Kontaktstruktur auf Basis einer mechanischen Befestigungsstruktur und eines Verbindungselements gemäß einem Ausführungsbeispiel.

The figures show the following views in detail.

• Fig. 1 shows a schematic representation of an electric hair straightener according to an embodiment;
• Fig. 2 shows a meander-shaped configuration of an electrical resistance structure of an electric heating plate of an electric hair straightener according to an embodiment;
• Fig. 3 shows a spiral configuration of an electrical resistance structure of an electric heating plate of an electric hair straightener according to an embodiment;
• Fig. 4 shows a cross-sectional view of an electric heating plate of an electric hair straightener according to an embodiment without an electrical contact structure;
• Fig. 5 shows a cross-sectional view of an electric heating plate and a solder-based based electrical contact structure;
• Fig. 6 shows a cross-sectional view of an electric hot plate with a spring contact based electrical contact structure according to an embodiment; and
• Fig. 7 shows a cross-sectional view of an electric heating plate and an electrical contact structure based on a mechanical fastening structure and a connecting element according to an embodiment.

Detailed description of the drawings

In the following description of the accompanying drawings, which show embodiments of the present invention, like reference characters designate like or similar components. Further, summary reference numbers are used for components and objects that occur multiple times in one embodiment or in a drawing, but are described together in terms of one or more features. Components or objects which are described by the same or by the same reference numerals may be the same, but possibly also different, in terms of individual, several or all features, for example their dimensions, unless otherwise explicitly or implicitly stated in the description.

Fig. 1 shows a schematic representation of an electric hair straightener 100 according to an embodiment, which is also referred to as Straightener. The hair straightener 100 has two arms 120-1 and 120-2, which are pivotable relative to one another about a hinge 110, on each of which an electric heating plate 130-1 and 130-2, which is also referred to as a smoothing plate, are arranged. The two heating plates 130 are in this case arranged such that they are opposite each other at a pivoting together of the two arms 120, so that between these hair can be introduced, which should be smoothed by a heat effect of the electric heating plates 130.

The heating plates 130 here each have a substrate 140-1, 140-2, which is or can be made of an electrically insulating material, for example. The substrates 140 may thus be made, for example, of a ceramic, for example of a glass ceramic, but also of a glass, for example a quartz glass, consist. The substrates 140 are in this case designed such that they form mechanically stable objects that can impart mechanical stability to other structures. They thus differ in particular from coatings and layers.

The substrates 140 and the heating plates 130 each have a front side 150-1 and 150-2, which are arranged and aligned so that the hair of a user of the electric hair straightener between the two front sides 150 are inserted during operation can. The front sides 150 of the two heating plates 130 and their substrates are so designed substantially flush with a housing of the arms 120 or stand out about this so out so that the hair can be brought into contact with the front sides 150 of the heating plates 130.

The heating plates 130 also each have a rear side, which coincide with main surfaces 160-1, 160-2 of the two substrates 140-1, 140-2 in the embodiment shown here. These are opposite to the front sides 150 and facing an interior of each arm 120. The substrates 140 in this case form both the front sides 150 and the main surfaces 160, ie the rear sides of the respective heating plates 130. The main surfaces 160 thus also represent those of the substrates 140. In other exemplary embodiments, the main surface 160 of the substrate 140 can also be separated from the front surface 160. or rear side of the heating plate 130 may be different.

The heating plates 130 furthermore each have an electrical resistance structure 170 - 1, 170 - 2, which is configured substantially two-dimensionally and has an electrically conductive design. The electrical resistance structure 170 can thus be realized, for example, on the basis of an electrically conductive, two-dimensionally structured resistance layer 180-1, 180-2 or comprise this. The resistive layers 180 may thus comprise, for example, tin oxide or zinc oxide, preferably in doped form, graphite, graphene and / or carbon nanotubes (CNT). However, they can also be made of other materials.

In this case, the resistive layers 180 each have a layer thickness which is adapted to the exact operating conditions of the resistive structures 170. The layer thicknesses of the resistive layers 180 thus go next to a geometric one Embodiment of the resistor structures 170, the choice of materials and the same other parameters in the realized resistance value of the electrical resistance structure 170 a. On the basis of an intended or specified heating power and voltages applied to the resistor structures 170, the electrical resistance values of the resistor structures 170 are determined accordingly. In other words, based on the voltages applied to the electrical resistance patterns 170, an intended heating power of the corresponding heating plate 130, and the exact geometry of the resistance structure 170, the layer thickness of the resistance layer 180 is determined. This is often at most 100 microns, but may also assume lower values in other embodiments. For example, the layer thickness may be limited to at most 50 μm, at most 20 μm, at most 10 μm, at most 5 μm, at most 3 μm or at most 1000 nm and below. Thus, in embodiments, the layer thickness may be, for example, at most 500 nm, at most 300 nm, at most 200 nm, at most 100 nm, or even at most 50 nm.

The heating plates 130 each have a first contact structure 190-1 or 190-1 'and a second electrical contact structure 190-2 or 190-2', which are arranged on the heating plate 130. In this case, the contact structures 190 are designed in such a way that they allow an electrically conductive connection between the respective resistance structures 170 and an electrical circuit 200 arranged outside the heating plate 130 via an electrical supply line 210. The electrical circuit 200 does not necessarily form a complete circuit. Rather, it may also comprise only part of a circuit, possibly even only a single electrical switching component. The electrical circuit 200 may thus comprise, for example, only a switch, a potentiometer or a display, for example a light-emitting diode.

The electrical contact structures 190 are in the in Fig. 1 shown embodiment of an electric hair straightener 100 configured such that the supply line 210 extends beyond a defined by the resistive structures 170 level. In this case, the plane concerned corresponds to the plane of the corresponding resistance layers 180 due to the essentially two-dimensional configuration of the resistance structures 170. Since the resistance layers 180 are here on of the main surface 160 of the substrates 140 and the heating plates 130, the plane is also substantially coincident with the main surface 160 of the respective heating plates 130. The supply line 210, which connects the resistance structure 170-2 of the heating plate 130-2 to the circuit 200, in this case runs over the hinge 110.

The detailed design of the electrical contact structures 190 is in connection with the Fig. 4 to 7 explained in more detail.

Unlike the electric hair straightener 100 off Fig. 1 Today hairglätterheizplatten is used in conventional electric hair straighteners largely consisting of a continuous casting, in which a heater, usually a ceramic heater or a PTC thermistor (positive temperature coefficient) is pressed. The material of the continuous casting profile is usually an aluminum alloy, which has a high thermal conductivity with values of about 200 W / (m · K), the exact value of which may depend on the alloy composition. In principle, comparable configurations can also be used for hair straightener hotplates made of ceramic or glass ceramic. However, ceramic, glass ceramic and glasses have a much lower thermal conductivity compared to aluminum alloys, which is only about 1 W / (m · K) in some cases.

In the case of a heating plate 130, as used in an exemplary embodiment of an electric hair straightener 100, it is therefore appropriate to use the heating, ie the electrical resistance structure 170, directly on the underside, the main surface 160 of the substrates 140, that is to say the plates 130, for example to place. The resistance structures can then be produced from coatings which, depending on the heating conductor material, can be a few nanometers to a few 10 .mu.m thick and can be applied, for example, as part of a thin-film or thick-film process.

As related to the FIGS. 2 and 3 will be explained in more detail, these resistor structures 170 are configured substantially two-dimensional, for example, implemented on the basis of an electrically conductive, two-dimensionally structured resistor layer 180. An essential aspect of these two-dimensional heaters on the back of the Haarglätterheizplatten 130, however, represents their electrical contact. In the context of exemplary embodiments, the first and second contact structures 190 are used for this purpose.

The basic structure of such a heating system (resistance structure 170) on the Haarglätterheizplattenrückseite so includes a coating having an electrical resistance value, whereby this coating is heated when current flows. These coatings can, for. As tin oxide or zinc oxide layers, which are often doped with other chemical elements. Likewise, graphite, graphene or CNT-containing coatings can be used.

Starting and ending point of the corresponding resistive coating, ie the points or locations at which the current is fed or subtracted, can hereby preferably be formed by contact surfaces. These contact surfaces are preferably made of highly electrically conductive materials, for example, with a high proportion of silver and / or copper in contact. However, the implementation of such contact surfaces is optional.

By way of example, these contact surfaces, just like the electrical resistance structures 170, can be applied by a screen-printing method or another two-dimensional structuring technique of the thin-film or thick-film technique.

In other embodiments, an electric hair straightener 100 may also be implemented with only a single heating plate 130, for example, provided only in one of the arms 120 concerned. In addition, the arms 120 need as little, as in Fig. 1 is hinted to be formally matched to each other. They can be different from each other.

Fig. 2 FIG. 2 shows a plan view of the main surface 160 of a heating plate 130 and of the substrate 140 behind it. The electrical resistance structure 170 in this case has a first contact surface 220-1 and a second contact surface 220-2, via which the current is fed to heat up the resistance structure 170 can be deducted. The two contact surfaces 220 are in the in Fig. 2 shown embodiment of a heating plate 130 via a meandering resistance structure connected with each other. This has a plurality of first resistance sections 230-1, ..., 230-5, which are interconnected by second resistance sections 240-1, ..., 240-4. More specifically, two first resistor sections 230 are electrically connected to each other by a second resistor section 240, with the second resistor sections 240 opening into the first resistor sections 230 at an angle different from 0 °. At the in Fig. 2 shown embodiment of a heating plate 130, the second resistance portions 240 and the first resistance portions 230 are substantially interconnected by right angles, ie by angles of substantially 90 °.

Of course, in other embodiments, the corresponding angles may be different, for example, a corresponding resistor structure 170 may be implemented based on a hexagonal geometry. Also, the number of the parallel straight line first connecting portions 230 and the number of the corresponding second connecting portions 240 can be varied. In this case, the resistance structure 170 has only at least three corresponding first resistance sections 230. The second resistance sections do not have to be implemented in a straight line by far, but can for example be bent. Also, the first resistance portions 230 may be performed bent accordingly, provided that they are parallel to each other. For example, these can not only be found in the Fig. 2 shown straight lines, ie as sections of mathematical lines, but also in the form of waves or other curved structures are implemented.

Fig. 3 shows a further heating plate 130 according to an embodiment or its underlying substrate 140. Also on this heating plate 130, an electrical resistance structure 170 has been implemented on a main surface 160, which connects two contact surfaces 220-1 and 220-2 together. Unlike the in Fig. 2 However, this embodiment shown is configured spiral and not meandering. For the sake of completeness, it should be mentioned at this point that it is also possible to implement a helical resistance structure 170 based on an angular or straight line first and second resistance sections 230, 240.

Fig. 4 shows a cross-sectional view through a heating plate 130, as can be used in an electric hair straightener 100 according to an embodiment used. The heating plate 130 has, as already associated with Fig. 1 has been described, a substrate 140 on which on a main surface 160, an electrical resistance structure 170 is arranged. In this case, the main surface 160 is the main surface of the substrate 140, which simultaneously forms the main surface 130 of the heating plate. The substrate 140 or the heating plate 130 further has a front side 150, to which, during the later operation of the electric hair straightener 100, for example, the hair of the user or the user can be guided along. In this case, the electrical resistance structure 170 is formed directly or directly on the main surface 160 of the substrate 140. Due to the electrical insulation property of the substrate 140, therefore, an additional layer for electrical insulation of the resistor structure 170 can be omitted.

As previously discussed, the electrical resistance structure 170 includes a resistive layer 180 that may include any of the foregoing materials. In this case, the resistance layer 180 is embodied as an electrically conductive, two-dimensionally structured resistance layer. In this case, the substrate 140 is typically designed as an electrically insulating substrate, so that this touching or contacting the user with the electrical resistance structure 170, which is also referred to as a heat conductor layer, is prevented. In this case, the substrate 140 can be made, for example, from a ceramic, for example, a glass ceramic, or from a glass, that is, for example, from a quartz glass, or can consist of this.

The electrical resistance structure 170 comprises in the in Fig. 4 shown layer system further comprises a further resistive layer 250 which is applied directly to the resistive layer 180. The further resistance layer 250 here forms the contact surface 220, via which the electrical contacting of the resistance structure 170 can take place. The further resistance layer 250 is thus arranged at at least one location at which the first and / or the second contact structure 190 are arranged. The contact structure 190 is in this case Fig. 4 not shown why it is in the representation in Fig. 4 is only a schematic structure of the heating plate 130 in cross section.

In this case, the further resistance layer 250 has a lower electrical resistance value parallel to the main surface 160 than an equally large area of the resistance layer 180. This makes it possible for an electrical current introduced into the resistance structure 170 via the contact surface 220 to be essentially parallel to the main surface 160 distribute the further resistive layer 250 before the current is introduced into and transferred through the resistive layer 180. While the resistance layer 180, ie the heat conductor layer, is often made of a material which has a comparatively high electrical resistance value, for example tin oxide or zinc oxide (preferably doped), graphite, graphene or carbon nanotubes, the further resistance layer 250 is often made of one material manufactured, which has a higher electrical conductivity. For example, the corresponding material of the further resistance layer may comprise a higher proportion of silver, copper or another material. The contact surfaces 220 and / or the further resistance layer 250, just like the resistance layer 180, can also be applied, for example, by means of a screen-printing method or another method of the thin-film or thick-film technique.

In other words, the contact surfaces 220 preferably have a high layer thickness compared to the resistive coating of the resistive layer 180 in order to reliably ensure a good current flow within the contact surfaces 220 and to be able to conduct the current as uniformly as possible to the resistive coating 180.

In a specific implementation of a heating plate 130, it may be advisable to perform the further resistance layer 250 such that it between the locations where the first and the second contact structure 190 causes the electrical connection to the resistance structure 170, to interrupt. This may make it possible to avoid or prevent a short circuit of the electrical resistance layer 180.

In the following, various possibilities are now to be carried out in order to connect the contact surfaces 220 with an external power supply, that is to say, for example, in FIG Fig. 1 shown circuit 200 to electrically connect. So shows Fig. 5 an embodiment of a heating plate 130, in which, in contrast to the in Fig. 4 shown layer structure the contact surface 220 is an electrical lead 210 applied by means of a solder 260.

As solders, for example, solders 260 tuned to the corresponding material pairings of the resistance layer 180, the further resistance layer 250 and the electrical supply line 210 can be used. These may be, for example, conventional solders, but it may also be used other materials, such as the material from which the contact surface 220 is made, so for example, the material of the further resistive layer 250. In other embodiments may optionally also a Implementation of the further resistive layer 250 is omitted, so that in such a case, the contact surface 220 is formed directly through the resistive layer 180.

The electrical supply line 210 serves in this case the Stromzu- or -abfuhr and may for example comprise a wire or a leaf spring. Fig. 5 shows a contact structure 190, which is realized on the basis of a solder connection between the contact surface 220 and the electrical supply line 210 forming wire. Alternatively or additionally, the contact surface 220 in the context of the contact structure 190 can also be implemented, for example, with a leaf spring, for example made of a silver foil.

A leaf spring thus allows in principle an additional strain relief of the overall system, wherein to improve a connection between the leaf spring and the corresponding contact surface, the leaf spring may also have one or more holes to allow additional mechanical clamping.

Alternatively to the in Fig. 5 If necessary, the supply line 210 can also be formed as part of the contact structure 190 by means of an electrically conductive bond or comprise this. Thus, the electrical supply line 210 can be mechanically and electrically fixed in the context of the contact structure 190, for example by means of an electrically conductive adhesive, wherein the adhesive can be adjusted with respect to its material pairing of the materials used of the supply line 210 and the material of the contact surface 220 to a corresponding warranty the electrical conductivity of the overall structure and a corresponding To allow temperature resistance. Likewise, other requirements may be taken into account when selecting the materials to be used.

As electrically conductive adhesives, for example, one- or two-component synthetic resins or solvent-based or solvent-free paints can be used, to which a corresponding electrically conductive filler material is attached. Examples of suitable filling materials are silver, gold, carbon, copper, tin, nickel, platinum, palladium or bronze. For example, the lead 210 can be attached to the contact surface 220 by means of conductive silver. Optionally, it may be advisable to cure the corresponding contact structure 190 accordingly.

Fig. 6 shows a cross-sectional view through a heating plate 130 according to an embodiment in which the supply line 210 is formed by means of a spring-contact connection with the resistor structure 170. In other words, shows Fig. 6 an embodiment of a heating plate 130, wherein the contact structure 190 comprises an electrical spring contact 270. The spring contact 270 is in this case designed such that it is in contact with the contact surface 220 of the resistance structure 170 by a force brought about by the spring contact 270 such that the electrical connection between the supply line 210 and the resistance structure 170 is created. For this purpose, the spring contact 270 is designed as a spring contact pin or contact pin unit, which comprises a spring element 280 and a contact surface 290 electrically connected to the supply line. The contact surface 290 is hereby designed to be brought into contact with the contact surface 220 of the resistance structure 170. The contact surface 290 is in this case formed by a sleeve 300, in the interior of which the spring element 280 is arranged in the form of a spring. The spring element 280 is in this case electrically connected to the electrical supply line 210. The electrical contact of the contact surface 290, so the sleeve 300, in this case takes place via a contacting contact between the spring element 280 and the sleeve 300th

At the in Fig. 6 shown embodiment of the contact structure 190 in the form of a spring contact so the power feed component or Stromabzugskomponente by means of acting as a spring spring element 280 on the Contact surface 220 pressed. The sleeve 300 at least partially surrounds the spring element 280.

While Fig. 6 shows an embodiment in which a spring contact pin or a component which is modeled after a spring contact pin is used, in other embodiments, a leaf spring can also be used. It makes sense to design the components on the material side so that they conduct the current well. It may therefore be advisable, if appropriate, to manufacture the sleeve 300 and / or the spring element 280 from a material which forms a good electrical conductivity with the material of the contact surface 220.

Fig. 7 shows a cross-sectional view through a further heating plate 130 according to an embodiment, in which the contact structure 190 by means of a mechanical fastening structure 310 and a connecting element 320 takes place. More specifically, this is a screw contact connection, as described in more detail below. In this case, the heating plate has at least one mechanical fastening structure 310, which on or in the substrate 140 in the in Fig. 7 shown embodiment is formed. The mechanical fastening structure 310 is in this case designed in such a way as to create a mechanical connection with the mechanical connecting element 320 of the contact structure 190, which likewise makes possible an electrical connection. The connecting element 320 is in this case mechanically connected to the supply line 210 and at least partially designed to be electrically conductive in order to provide the electrical connection to the supply line 210 with the resistance structure 170.

So is in the in Fig. 7 In the exemplary embodiment shown, the attachment structure 310 is configured as a threaded blind hole 330 in the substrate 140, which extends from the main surface 160 into this. In the threaded blind hole 330, a screw 340, which is connected to the supply line 210 extends. The screw 340 also extends through the further resistance layer 250 and the resistance structure 180.

Fig. 7 FIG. 14 shows such an embodiment in which the contact structure 190 comprises a screwed connection element. Depending on the plate material, it may be possible to hole-like Incorporate indentations in the plate or the substrate 140, in which then the corresponding connecting elements 320 of the contact structure 190 can be fixed. At the in Fig. 7 In the embodiment shown, a thread has been introduced into the substrate 140, via which, for example, wires of the feed line 210 can then be screwed to the connecting element 320, clamped or soldered there. The contact structure 190 is designed here as a screwed contact, in which the supply line 210 can be connected, for example with the aid of a cable lug with the screw 340.

However, in other embodiments, other attachment structures 310 and connectors 320 may also be used. Thus, for example, the attachment structure 310 can be implemented as a blind hole, bore or threaded hole. Accordingly, the connecting element 320 can also be designed as a clamping element. This may make it possible to use a clamped, clipped or latched connection element 320.

In further embodiments of a heating plate 130, it may be possible to interchange the "positive" and "negative" structures. Thus, it may be possible, for example, to design the mechanical fastening structure in such a way that it comprises a projection, for example a pin or a threaded pin, which extends beyond the contact surface 220, for example. Thus, it may be possible, for example, that a raised wire is implemented on the contact surface 220, via which a sleeve connected to the power line wire, that is to say the lead 210, can be slipped. The connecting element 320, which is connected to the feed line 210, would in this case comprise, for example, the aforementioned sleeve. Of course, the above-mentioned and shown in the different figures connection techniques can be combined. So it may be possible, for example, in the Fig. 6 or 7 shown contact structures 190 additionally provided with a soldering. Further combinations, for example the combination of a mechanical fastening structure and a corresponding connecting element together with a spring contact, can optionally be implemented.

Embodiments of an electric hair straightener 100 thus make it possible to electrically contact two-dimensional resistor structures 170, ie corresponding heaters on hair straightener heating plates 130. If appropriate, they can allow a more stable connection of the two-dimensional resistance structures 170 to the third dimension of the power supply components, ie the leads 210; two dimensions are defined by the substantially two-dimensional configuration of the electrical resistance structure 170. This may make it possible, if necessary, to ensure a more reliable feed of the flow of current into the heater, that is to say into the resistance structure 170. Optionally, an electric hair straightener 100 according to an exemplary embodiment also develop a mechanical damping effect, so that this or its contact structures 190 can support the storage of the heating plate 130.

Exemplary embodiments of an electric hair straightener can thus make possible, with simple structural and cost-effective means, an easier and / or more resistant connection of an electrical connection between a substantially two-dimensional electrical resistance structure of an electrical heating plate and an electrical circuit arranged outside the same. If appropriate, this can be visually pleasing and / or robust.

The features disclosed in the foregoing description, the claims and the drawings may be of importance both individually and in any combination for the realization of the invention in its various forms.

LIST OF REFERENCE NUMBERS

100

Electric hair straightener

110

hinge

120

poor

130

heating plate

140

substratum

150

front

160

main surface

170

resistance structure

180

resistance layer

190

Contact structure

200

circuit

210

supply

220

contact area

230

First resistance section

240

Second resistance section

250

Further resistance layer

260

solder

270

spring contact

280

spring element

290

pressing surface

300

shell

310

attachment structure

320

connecting element

330

Threaded blind hole

340

screw

Claims (14)

1. Electric hair straightener (100) having the following features:

   an electric heating plate (130) which has an essentially two-dimensional electric resistance structure (170);

   an electric circuit (200) arranged outside the heating plate (130); and

   a first electric contact structure (190-1) and a second electric contact structure (190-2) differing from the first contact structure (190-1), that are arranged on the heating plate (130) and create an electrically conductive connection of the resistance structure (170) to the electric circuit (200) by way of an electric supply lead (210),

   characterised in that

   the first and/or the second contact structure (190) comprise an electric spring contact (270) electrically connected to the supply lead (210),

   and that the resistance structure (170) comprises a contact surface (220) electrically connected thereto, wherein the spring contact (270) exerts a force and by virtue of the force is in contact with the contact surface (220, such that the electric connection to the resistance structure (170) is created.
2. Electric hair straightener (100) according to claim 1, in which the first and/or the second electric contact structure (190) creates the electric connection (210) to the resistance structure (170) by way of the supply lead, such that the supply lead (210) extends beyond a plane defined by the resistance structure (170).
3. Electric hair straightener (100) according to one of the preceding claims, in which the first and/or the second contact structure (190) comprises a soldering and/or an electrically conductive bonding of the supply lead (210) to the resistance structure (170).
4. Electric hair straightener (100) according to claim 1, in which the spring contact (270) comprises a leaf spring and/or a spring contact pin.
5. Electric hair straightener (100) according to one of the preceding claims, in which the heating plate (130) comprises at least one mechanical fastening structure (310) which is designed to create a mechanical connection to a mechanical connecting element (320) of the first and/or the second contact structure (190), wherein the connecting element (320) is mechanically connected to the supply lead (210) and is configured to be at least partially electrically conductive in order to provide the electric connection to the resistance structure (170).
6. Electric hair straightener (100) according to claim 5, in which the fastening structure (310) has a recess in the heating plate, for example a blind hole, a bore, a threaded blind hole (330) and/or a threaded bore, and/or comprises a projection, for example a pin and/or a threaded pin, and/or in which the connection element (320) comprises an electrically contactable connecting element, for example a screw connection, a locking element and/or a sleeve.
7. Electric hair straightener (100) according to one of the preceding claims, in which the resistance structure (170) comprises an electrically conductive, two-dimensionally structured resistance layer (180).
8. Electric hair straightener (100) according to claim 7, in which the resistance layer (180) comprises tin oxide, doped tin oxide, zinc oxide, doped zinc oxide, graphite, graphene and/or carbon nanotubes.
9. Electric hair straightener (100) according to one of claims 7 or 8, in which a layer thickness of the resistance layer (180) is a maximum of 100 µm.
10. Electric hair straightener (100) according to one of claims 7 to 9, in which the resistance structure (180) comprises, at least at one location at which the first and/or the second contact structure (190) brings about the electric connection to the resistance structure (170), a further resistance layer (250) directly applied to the resistance layer (180).
11. Electric hair straightener (100) according to claim 10, in which the further resistance layer (250) has a lower electric resistance value in a plane defined by the resistance structure (170) than an equally large area of the resistance layer (180).
12. Electric hair straightener (100) according to one of the preceding claims, in which the heating plate (130) comprises an electrically insulating substrate (140), for example a ceramic substrate, a glass ceramic substrate, a glass substrate or a quartz glass substrate, with a main surface, and in which the resistance structure (170) is applied directly to the main surface (160).
13. Electric hair straightener (100) according to claim 12, in which the main surface (160) of the substrate (140) forms a main surface of the heating plate (130).
14. Electric hair straightener (100) according to one of the preceding claims, in which the resistance structure (170) has at least three parallel first resistance portions (230), of which in each case two first resistance portions (230) are directly electrically connected by a second resistance portion (240), wherein the second resistance portions (240) are connected to the first resistance portions (230) at an angle differing from 0°, and/or in which the resistance structure (170) comprises a spiral-shaped resistance portion.

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