Protective helmet equipped with an improved visor

Abstract

A protective helmet (1) for practicing sports or using motorized vehicle use according to the present invention has a visor (3) engaged with a cap (2) and comprises a structural lens (41) that is at least partially transparent, a liquid crystal layer (43), and a protective layer (44) laminated to the inner face (432) of the liquid crystal layer (43). Innovatively, a helmet thus made has technical features aimed at optimally protecting the GH liquid crystal layer from unwanted mechanical stresses that could compromise the uniformity of transparency thereof.

Description

"PROTECTIVE HELMET EQUIPPED WITH AN IMPROVED VISOR"DESCRIPTION

[0001] The obj ect of the present invention is a protective helmet for practicing sport and / or using motori zed vehicles , equipped with an eye visor, in particular a variable transparency visor .

[0002] Protective helmets often include a protective eye visor . In some cases , this visor is only intended to protect the eyes of the user against the entry of debris , dust , or simply against the wind . In other cases , however, the visor also provides protection against excessive light .

[0003] Generally, protection from light is achieved simply through the use of pigments that cause the visor to transmit only a fraction of the incident light . Filters of this type are generally classi fied into categories from 0 to 4 with increasing levels of absorption . However, in many situations , the user needs to have a level of light fi ltering that varies according to the di f ferent levels of external brightness , such as in the case of a motorcyclist who from a sunlit area passes through a tunnel .

[0004] T echnologies that seek a solution to this problem are known . However, such known technologies have limitations that actually make them inef fective .

[0005] Finally, lenses that use layers of liquid crystals are known, and are the only ones that are able to react quickly to changes in ambient light . However, lenses of this type are still substantially unused, given the persistence of a number of issues , including : low maximum brightness of the filter, presence of unwanted polari zations , interference with other transparent elements , and undesirable reactions to mechanical stresses . For these reasons , said lenses find application in the field of protective devices for welding, wherein TN ( twisted nematic ) type planar liquid crystal LC screens are widely used . However, said screens are not suitable for sunlight protection under normal conditions , as they are in fact too dark in their maximum transmission state and have a very small field of vision . Examples of lenses that use liquid crystals are known from the documents WO 2022 / 254349 Al and US 2011 / 283431 Al .

[0006] Device application techniques using GH ( Guest-Host ) liquid crystals are also known . This type of liquid crystal does not use polari zing filters and may therefore achieve transparencies much greater than 50% , making it potentially more suitable for use in sunlight protective devices under normal conditions . However, also this type of lens has a series of problems . In fact , GH-type liquidcrystal LC filters react to mechanical stresses by creating unwanted inhomogeneities within the transparency level . Most existing helmet visors are made in such a way that , when a GH-type LC layer is applied to them, said layer undergoes such deformations and mechanical stresses that the uni formity of its transparency is compromised . Helmet visors are furthermore typically made us ing the inj ection molding technique , which generates parts with residual internal stresses that interfere with liquid crystals thereby creating a birefringence ef fect typically called "rainbow" that renders vision uncomfortable .

[0007] Furthermore , the opening and closing system of the helmet visors usually prevents the film from being applied to the entire inner surface of the visor without creating interference with the seal that is usually used to prevent the passage of water and air between the visor and the cap .

[0008] The obj ect of the present invention is to solve the problems found in the state of the art in order to obtain a helmet equipped with a variable transparency visor that is truly ef fective and comfortable to use .

[0009] In particular, the obj ect of the present invention is to provide a helmet with a variable transparency visor provided with speci fic technical measures aimed atoptimally protecting the GH liquid crystal layer from mechanical stresses that would create undesirable inhomogeneities within the transparency level .

[0010] Said obj ect is achieved by a protective helmet according to claim 1 . The dependent claims disclose further advantageous embodiments of the invention .

[0011] The features and advantages of the protective helmet according to this invention will become apparent from the following description, given as a non-limiting example in accordance with the accompanying drawings , wherein :Figure 1 shows a perspective view of a protective helmet according to the present invention, in an exemplary embodiment ;- Figure 2 shows an exploded diagram of the structure of the lens assembly of the visor of the protective helmet , in an exemplary embodiment ;- Figure 3 shows a cross-sectional view of a protective helmet according to the present invention, in an exemplary embodiment ;Figure 4 shows a longitudinal-sectional view of a protective helmet according to the present invention, in a further exemplary embodiment ;Figure 5 shows a longitudinal-sectional view of a protective helmet according to the present invention, in a still further exemplary embodiment ;- Figure 6 shows in detail a cross-sectional view of the lens assembly of the visor of a protective helmet according to the present invention, in an exemplary embodiment ;- Figure 7 shows in detail a cross-sectional view of the lens assembly of the visor of a protective helmet according to the present invention, in a further exemplary embodiment .

[0012] With reference to the appended figures , 1 has been used to collectively denote a protective helmet equipped with a visor for the eyes for practicing sports or using motori zed vehicles according to the present invention .

[0013] The helmet 1 comprises a cap 2 , protecting at least part of the user' s head, to which is engaged a visor assembly 3 , protecting the user' s eyes .

[0014] The cap 2 has a frontal viewing opening 23 at the eye region of the user, which is intended to be closed by the visor assembly 3 at least when the helmet 1 is being used . Said opening is characteri zed by a closed perimeter in the case of full- face helmets ( as in Figure 1 ) , while it takes the form of a recess in the perimeter of the cap in the case of helmets without chin guards .

[0015] The cap 2 has , on both sides , a seat 21 arranged near the region of the ear of the user, adapted to accommodate a corresponding anchor pin 32 of the visorassembly 3 in such a way that said assembly is pivoted on the cap 2 for opening and / or closing the opening 23 .

[0016] The visor assembly 3 tilts between an open position, wherein the opening 23 is substantially free , and a closed position, wherein the opening 23 is closed . When in the closed position, the visor assembly 3 is in contact with a helmet seal 232 , preferably sealed, present on the edge 231 of the opening 23 of the cap 3 .

[0017] In one embodiment , the visor assembly 3 is attached to the cap 2 . In a further embodiment , the visor assembly3 is removable from the cap 2 , for example , to be replaced with a di f ferent visor assembly to adapt the helmet 1 to speci fic lighting situations .

[0018] The visor assembly 3 comprises a variable transparency lens assembly 4 that is truly ef fective and comfortable in use .

[0019] As shown for example in Figure 2 , the lens assembly4 comprises a structural lens 41 or outer lens . The structural lens 41 is at least partially transparent .

[0020] Said lens may be made with transparent materials and without the addition of pigments resulting in a light transmission close to 100% . Or it may be made by using materials or combinations of pigments , materials , and surface treatments in such a way as to filter out some of the non-visible light or radiation, even possiblyunevenly over the whole spectrum to achieve optimal vision under di f ferent environmental conditions .

[0021] Preferably the structural lens 41 is made of plastics material , such as polycarbonate or polyamide .

[0022] In one embodiment , the structural lens 41 is a thermoformed sheet , obtained by thermoforming or flexing a sheet of polymer material .

[0023] In an embodiment intended for use in speci fic lighting conditions , the structural lens 41 is pigmented to modulate the absorption spectrum, speci fically in this case the structural lens 41 may also be pigmented to modulate the contrast in speci fic lighting situations , for example by increasing it .

[0024] The structural lens 41 has an outer surface 411 and an inner surface 412 , facing the cap 2 .

[0025] The outer surface 411 of the structural lens 41 is preferably treated with one or more coatings , such as an anti-scratch, and / or mirroring, and / or anti-reflective , and / or multilayer coating .

[0026] The lens assembly 4 comprises a liquid crystal layer 43 , provided with an outer face 431 , facing the structural lens 41 , and an inner face 432 facing the cap 2 .

[0027] The liquid crystal layer 43 is preferably of the GH ( Guest-Host ) type . In this type of layer dichroicpigments are dispersed in a matrix of liquid crystals ; the electric field drives the orientation of the liquid crystals , which, in turn, drive the orientation of the pigments . Typically in the "active" state , the crystals assume a helical configuration and the pigments are arranged in planes parallel to the surface of the layer, whilst in the " inactive" state , crystals and pigments are arranged perpendicularly to the surface of the layer .

[0028] As shown in Figures 6 and 7 , the liquid crystal layer 43 comprises at least two substrates 434 , facing therebetween, and a peripheral seal 438 . A closed space is defined between said substrates 434 and the peripheral seal 438 wherein a mixture of liquid crystals is contained .

[0029] The substrates 434 of the liquid crystal layer 43 are preferably spaced apart by means of cylindrical or spherical spacer elements 433 , which are also arranged within the closed space wherein the liquid crystal mixture is contained .

[0030] In a preferred exemplary embodiment , shown in Figure 7 , the peripheral seal 438 is a seal that is wider than traditional peripheral seal s , such as the one in Figure 6 , and extends further into the closed space between the substrates 434 . In particular, the peripheral seal 438 extends at least below, and preferably beyond, theprojection of the contact line between the helmet seal232 (shown schematically with a ball in Figure 7) and the liquid crystal layer 43. In other words, the projection of the contact line of the helmet seal 232 falls inside the peripheral seal 438 of the liquid crystal layer 43. Advantageously, this solution prevents unwanted mechanical stresses from being generated within the liquid crystal layer 43.

[0031] Preferably, the liquid crystal layer 43 has a visible light transparency of at least 60% in the lightest state thereof and at most 40% in the darkest state thereof. For example, the LC layer may have a transparency of about 22% in the darkest state thereof and about 65% in the lightest state thereof.

[0032] Preferably, the liquid crystal layer 43 is mounted to the rear of the structural lens 41, i.e., on the side of the inner surface 412, preferably by means of an optically clear adhesive (OCA) .

[0033] In one embodiment, shown for example in Figure 2, the inner surface 412 of the structural lens 41 is characterized by a Gaussian substantially 0 curvature, for example it may be substantially conical, conoidal, cylindrical. In another embodiment, the inner surface 412 of the structural lens 41 is characterized by a substantially torical curvature, i.e., it has a curvaturein the horizontal plane that is greater than that in the longitudinal plane.

[0034] Preferably, internally to the liquid crystal layer 43, i.e., on the side of the inner face 432, anti-fog and / or anti-reflection treatments, or a real additional layer equipped with anti-fog and / or anti-reflection treatment, may be applied.

[0035] The lens assembly 4 preferably comprises a depolarizing layer 42 arranged externally to the liquid crystal layer 43, i.e., at the outer face 431. The depolarizing layer 42 is therefore arranged between the structural lens 41 and the liquid crystal layer 43.

[0036] The depolarizing effect is preferably achieved by means of a birefringent layer characterized by a wave phase shift between the two optical axes of greater than 1500nm.

[0037] Advantageously, as shown in Figure 2, lens assembly 4 comprises a protective layer 44 arranged inside the liquid crystal layer 43, i.e., at the inner face 432. The protective layer 44 is therefore arranged between the liquid crystal layer 43 and the face of the user.

[0038] The protective layer 44 is laminated directly to the inner face 432 of the liquid crystal layer 43.

[0039] The protective layer 44 is preferably made of plastic material.

[0040] The protective layer 44 preferably has a thickness of between 0 . 4 mm and 2 mm .

[0041] Insofar as the liquid crystal layer 43 is very thin and extremely sensitive to mechanical stresses , the presence of the protective layer 44 improves the structural strength thereof and avoids unwanted and annoying visual ef fects .

[0042] The visor assembly 3 comprises an electronic board 5 adapted to control the liquid crystal layer 43 . The electronic board 5 produces a signal , wherein the intensity thereof increases as ambient light increases . The electronic board 5 comprises , or is connected to , a photovoltaic panel and an electronic circuit supplied by the photovoltaic panel . The photovoltaic panel comprises at least one photovoltaic panel . Pre ferably the photovoltaic panel operates simultaneously as a sensor of the amount of light within the environment and as a power supply for the liquid crystal layer 43 ; in fact , the greater the amount of light that impacts the photovoltaic panel , the greater the power generated by the photovoltaic panel , the greater the amount of power with which the liquid crystal layer 43 is fed and the more said LC lens darkens .

[0043] Preferably, the response curve between the input signal and output signal from the electronic board 5 maybe changed according to the user' s needs . Said response curve is preferably characteri zed by a threshold value wherebelow there is no activation of the liquid crystal layer 43 .

[0044] Advantageously, the photovoltaic panel is located close to the structural lens 41 , thus receiving more light . In the exemplary embodiments of Figures 3 and 5 , the electronic board 5 with the photovoltaic panel is located directly to the rear of the structural lens 41 , and the photovoltaic panel faces the structural lens 41 .

[0045] In a preferred exemplary embodiment , the visor assembly is made in such a way that the photovoltaic panel is not externally visible . The area of the outer surface 411 of the structural lens 41 in front of the photovoltaic panel is preferably treated with a multilayer or single-layer, preferably opaque , mirroring coating . The mirroring coating present within the area in front of the photovoltaic panel is preferably di f ferent from that which may be present within the vision area of the visor assembly 3 . The mirroring coating in front of the photovoltaic panel is preferably selective in such a way that it forms a pattern, a logo or a graphic of some kind . In a di f ferent embodiment of the present invention, the area of the outer surface 411 of the structural lens41 in front of the photovoltaic panel is covered by asemi-covering film, for example a micro-perforated film, which has an outwardly facing print , whilst towards the inside it is black .

[0046] Advantageously, the photovoltaic panel receives filtered light from the structural lens 41 and thus reacts to the same component of ambient light that the eye of the user receives , net of the intervention of the liquid crystal layer 43 .

[0047] In one embodiment , shown in Figure 3 , the structural lens 41 has , at the inner surface 412 , a lens recess 413 wherein both the liquid crystal layer 43 and the protective layer 44 and, where present , the depolari zing layer 42 are housed .

[0048] Preferably, the lens recess 413 has a depth that is such to accommodate all of the layers present , in such a way that the final layer facing the cap 2 does not protrude from the plane defined by the inner surface 412 of the structural lens 41 .

[0049] Preferably, at the side periphery 414 of the lens recess 413 there is a polymer filler material 415 , for example a resin, for filling the remaining free space , respectively, with the liquid crystal layer 43 , the protective layer 44 and, where present , with the depolari zing layer 42 . Advantageously, such a solution allows surface continuity to be obtained between theinner surface 412 of the structural lens 41 and the inner side of the protective layer 44 .

[0050] In the examples of Figures 3 and 5 , at the inner periphery of the lens assembly 4 which is intended to come into contact with the helmet seal 232 of the cap 3 , there is a covering layer 416 , which is preferably opaque . Said covering layer 416 extends to cover the inner contour of the protective layer 44 and, in proj ection, also to cover the inner contour of the liquid crystal layer 43 . In such solution, the filler material415 , where present , is also covered by the covering layer416 .

[0051] In one embodiment , shown in Figure 3 , the structural lens 41 has , at the inner surface 412 , a board recess 417 wherein the electronic board 5 is housed . Preferably, after having housed the electronic board 5 , the free space remaining inside the board recess 417 is filled with a filler material 415 , such as a resin .

[0052] In an alternative embodiment , shown in Figure 4 , the structural lens 41 is surrounded, at the outer periphery thereof , by a frame 45 that is pre ferably opaque and obtained by overmolding . The frame 45 , vertically protruding with respect to the inner surface 412 of the structural lens 41 , defines a lens recess 413 in which both the liquid crystal layer 43 and the protective layer44 and, where present , the depolari zing layer 42 are housed .

[0053] Preferably, also in the embodiment of Figure 4 , the lens recess 413 has a depth that is such to accommodate all of the layers present in such a way that the final layer facing the cap 2 does not protrude from the plane defined by the inner surface 412 of the structural lens 41 . The frame 45 pre ferably fills the entire space with the liquid crystal layer 43 , the protective layer 44 and, where present , with the depolari zing layer 42 . Advantageously, such a solution allows surface continuity to be obtained between the inner surface of the frame 45 and the inner side of the protective layer 44 .

[0054] In one embodiment , shown in Figure 4 , the electronic board 5 is housed within a board recess 417 defined between the frame 45 , a front screen 418 , and a panel 419 .

[0055] In a further embodiment example , the electronic board 5 is housed within a board recess 417 defined between a front screen 418 and the frame 45 itsel f .

[0056] Preferably, the frame 45 is configured in such a way as to make a seal with the helmet seal 232 and prevent the passage of light outside the outer periphery of the liquid crystal layer 43 . In the embodiment of Figure 4 , the frame 45 completely surrounds the lens assembly 4 ofthe visor 3.

[0057] In an alternative embodiment, shown in Figure 5, the structural lens 41 is devoid of a recess or overmolded frame, and the liquid crystal layer 43 together with the protective layer 44 and, where present, the depolarizing layer 42, are fixed at the inner surface 412.

[0058] In such exemplary embodiment, the electronic board 5 is housed within a board recess 417 defined between the structural lens 41, the side walls of the other layers of the lens assembly (i.e., liquid crystal layer 43 and protective layer 44 and, where present, depolarizing layer 42) , and a panel 419.

[0059] In all of the exemplary embodiments presented, the board recess 417 is preferably arranged outside the periphery defined by the frontal opening 23 of the cap 2, in such a way that, when the visor 3 is lowered, the electronic board 5 is external to the periphery of the opening 23 and does not result in a significant reduction of the field of vision of the user. Advantageously, therefore, the photovoltaic panel is positioned in such a way that it is in an area of the field of vision of the user that is already occluded by the cap 2 of the helmet 1.

[0060] In all of the exemplary embodiments presented, the board recess 417 is preferably sealed i.e., leak-proof,and protects the electronic board 5 ; said board may alternatively or additionally be protected by protective coatings or embedded in resins .

[0061] In one embodiment , the helmet 1 includes a battery that may provide more power to the electronic board 5 ; possibly, this battery may also be used to power other electronic devices such as traditional or bone-conduction audio systems , intercoms , "head-up" or traditional displays , signal lights , emergency call systems , cameras , or sensors . Said battery may in turn be powered by solar cells , also applied to the outside of the helmet cap, or recharged by connecting the battery to the electrical grid .

[0062] In summary, therefore , the protective helmet 1 for sports or motori zed vehicle use according to the present invention comprises :- a protective cap 2 provided with a vision opening 23 ;- a visor 3 engaged with the cap 2 to cover the opening 23 , and comprising : a structural lens 41 , which is at least partially transparent ;-- a liquid crystal layer 43 , comprising at least two substrates 434 and a peripheral seal 438 defining a closed space containing a mixture comprising liquid crystals ; the liquid crystal layer 4 is controlled by anelectronic board 5 , being positioned inside the structural lens 41 , and being provided with an outer face 431 , facing the structural lens 41 , and an opposite inner face 432 ;-- a protective layer 44 laminated to the inner face 432 of the liquid crystal layer 43 .

[0063] Innovatively, a helmet equipped with a variable transparency visor according to the present invention has technical measures aimed at optimally protecting the GH liquid crystal layer from unwanted mechanical stresses that could compromise the uni formity of transparency thereof .

[0064] Advantageously, the protective layer laminated on the inner face of the liquid crystal layer protects it from unwanted deformations and mechanical stres ses .

[0065] Advantageously, the frame obtained by overmolding on the structural lens makes it possible to improve the stability of the lens assembly to mechanical stresses and to protect the liquid crystal layer from contact with the seals of the cap .

[0066] Advantageously, the enlarged peripheral seal of the liquid crystal layer protects the liquid crystal matrix from contact with the seals of the cap .

[0067] It is understood that a person skilled in the art , in order to meet contingent needs , could makemodifications to the device described above, all of which are contained within the scope of protection as defined by the following claims.

Claims

CLAIMS1. A protective helmet (1) for practicing sports or using motorized vehicles, comprises:- a protective cap (2) provided with a viewing opening (23) ; a visor (3) engaged with the cap (2) to cover the opening (23) , and comprising:-- a structural lens (41) that is at least partially transparent ;-- a liquid crystal layer (43) , comprising at least two substrates (434) and a peripheral seal (438) which define a closed space containing a mixture comprising liquid crystals; said liquid crystal layer (43) being controlled by an electronic board (5) , being positioned inside the structural lens (41) , and being provided with an outer face (431) , facing the structural lens (41) , and an opposite inner face (432) ;-- a protective layer (44) laminated to the inner face (432) of the liquid crystal layer (43) .

2. A helmet (1) according to claim 1, wherein said protective layer (44) has a thickness between 0.4 mm and 2 mm.

3. A helmet (1) according to claim 1 or 2, wherein, at an inner periphery of the visor (3) facing the cap (3) , there is an opaque covering layer (416) which alsoextends to cover an inner contour of the protective layer (44) .

4. A helmet (1) according to any one of the preceding claims, wherein the substrates (434) of the liquid crystal layer (43) are spaced apart from each other by means of cylindrical or spherical spacer elements (433) .

5. A helmet (1) according to any one of the preceding claims, wherein the cap (2) is provided with a helmet seal (232) around the opening (23) , and wherein the peripheral seal (438) of the liquid crystal layer (43) extends between the substrates (434) at least below the projection of a contact line between the helmet seal (232) and the liquid crystal layer (43) .

6. A helmet (1) according to claim 5, wherein the peripheral seal (438) of the liquid crystal layer (43) extends beyond said projection of the contact line between the helmet seal (232) and the liquid crystal layer ( 43 ) .

7. A helmet (1) according to any one of the preceding claims, wherein said liquid crystal layer (43) is of the GH type.

8. A helmet (1) according to any one of the preceding claims, wherein the visor (3) comprises a depolarizing layer (42) arranged between the structural lens (41) and the liquid crystal layer (43) .

9. A helmet (1) according to any one of the preceding claims, wherein the liquid crystal layer (43) is powered by a photovoltaic panel connected to the electronic board (5) .

10. A helmet (1) according to any one of the preceding claims, wherein the structural lens (41) is surrounded, at an outer periphery thereof, by a frame (45) obtained by overmolding, said frame (45) vertically protruding with respect to an inner surface (412) of the structural lens (41) , and wherein said frame (45) defines a lens recess (413) in which both the liquid crystal layer (43) and the protective layer (44) are housed.

11. A helmet (1) according to any one of claims 1 to 9, wherein : the structural lens (41) has, at an inner surface (412) , a lens recess (413) in which both the liquid crystal layer (43) and the protective layer (44) are housed, and wherein a polymer filler material (415) fills the free space between a side periphery (414) of the lens recess(413) and the liquid crystal and protective layers.

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