Protective helmet with a visor having an LC layer and an anti-polarization layer

Abstract

According to the invention, a protective helmet (1) for the practice of sporting activities or for using motor vehicles has a cap (2) with a front opening (23) in the area of ​​the user's eyes, closed by a visor assembly (3). at least one at least partially transparent structural lens (41); - a guest-host liquid crystal LC film (43) adapted to change its transparency level, arranged behind the structural lens (41); at least one power source for supplying power to the LC film (43); The helmet is characterized by having at least one depolarizing layer (42) disposed between the structure lens (41) and the LC film (43).

Description

Technical Field

[0001] The subject of the present invention is a protective helmet equipped with visors for the practice of sports activities and / or the use of motor vehicles.

Background Art

[0002] Protective helmets often include protective visors. In some cases, this visor may simply aim to prevent the intrusion of debris and dust or protect the eyes from the wind. However, in other cases, the visor also provides protection against excessive light.

[0003] Generally, protection against light is achieved by using pigments that allow the visor to transmit only a small part of the incident light. This type of filter is generally classified into categories (such as S0, S1, S2, etc.) with increasing absorption levels in sequence. However, there are many situations where it is necessary to change the level of light filtering according to different levels of external brightness, such as a motorcycle rider passing through a tunnel from a sunny place.

[0004] Technologies attempting to solve this problem are known. However, such known technologies have limitations and are actually ineffective due to these limitations.

[0005] It is known that photochromatic lenses are made of processed materials or materials that cause the color of the lens to darken in response to sunlight. However, such known lenses are too slow to respond to rapid changes in brightness. Furthermore, the optimal substrate for such treatment is glass, and glass is a material that is hardly suitable for protective devices.

[0006] Electrochromic lenses are typically known to use polymers whose optical properties can change when a magnetic field is applied. While faster than photochromic lenses, they are still considerably slower. Furthermore, the high power required to achieve the state change limits the maximum number of possible state changes, meaning this type of lens can only achieve automatic adaptation to ambient light if a bulky battery is available.

[0007] Finally, lenses using a liquid crystal layer are known and are the only lenses that can respond quickly to changes in ambient light. However, this type of lens is not yet practically used because many problems remain, such as low maximum filter brightness, the presence of unwanted polarization, interference with other transparent elements, and unfavorable reactions to mechanical stress. For these reasons, the lens is applied in the field of welding protection equipment where TN (twisted nematic) type planar liquid crystal (LC) screens are widely used. However, this screen is not suitable for sunlight protection under normal conditions; in fact, it is too dark at maximum transmittance and has a very narrow field of view.

[0008] Device application technology utilizing GH (guest-host) type liquid crystals is also known. Because this type of liquid crystal does not use a polarizing filter, it can potentially achieve transparency far exceeding 50%, making it potentially suitable for use in sun protection devices under normal conditions. However, this type of lens also has many problems. In fact, GH type liquid crystal filters react to mechanical stress, causing unwanted non-uniformity in transparency. Most existing helmet visors are made in such a way that when a GH type LC layer is applied, the layer is subjected to such deformation and mechanical stress, compromising the uniformity of its transparency. Furthermore, because helmet visors are generally made using injection molding technology, parts with residual internal stress that interfere with the liquid crystal are produced, resulting in a birefringence effect commonly known as a "rainbow," which makes the view unpleasant. [Overview of the Initiative]

[0009] The objective of the present invention is to solve problems found in the state of the art in order to obtain a helmet with a variable transparent visor that is truly effective and comfortable to use.

[0010] The objective is achieved by the protective helmet described in claim 1. Further advantageous embodiments of the invention are disclosed in the dependent claims.

[0011] The features and advantages of the protective helmet according to the present invention will become apparent from the following description, which is given as a non-limiting example with respect to the accompanying drawings. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view of a protective helmet according to an embodiment of the present invention. [Figure 2] Figure 1 is a cross-sectional view of the protective helmet. [Figure 3] This figure shows the details of the visor of the protective helmet shown in Figure 1. [Figure 4] This is a side view of a protective helmet according to a further embodiment of the present invention. [Figure 5] Figure 4 is a cross-sectional view of the protective helmet. [Figure 6] This is a cross-sectional view of the protective helmet shown in Figure 1 in a further embodiment. [Figure 7] Figure 6 shows a detailed view of the helmet visor. [Figure 8] This is an exploded view of the structure of the lens assembly of the visor of a protective helmet according to the present invention. [Modes for carrying out the invention]

[0013] Referring to the attached drawings, reference numeral 1 is used to collectively refer to protective helmets with visors for the eyes for the practice of sports activities or the use of motorized vehicles according to the present invention.

[0014] The helmet 1 consists of a cap 2 that protects at least a part of the user's head, and a visor assembly 3 for protecting the user's eyes is engaged with the cap 2.

[0015] The cap 2 has a rigid outer shell 21 such as plastic or composite material, and a foldable inner shell 22 such as foamed polyurethane or foamed polystyrene.

[0016] On the inner shell 22, the side that contacts the user's head is covered with pads mainly made of cloth, which are adapted to improve the comfort during helmet use.

[0017] Preferably, the cap 2 has a communication system. For example, the helmet 1 has a bone conduction audio system.

[0018] Preferably, the cap 2 may also include additional parts typical of helmets, such as ventilation holes, spoilers, aerodynamic appendages, signal lights, communication systems, displays, etc.

[0019] The cap 2 has a front opening 23 in the area of the user's eyes, which is intended to be closed by the visor assembly 3 at least when the helmet 1 is in use. The opening is characterized in that it is closed around in the case of a full-face helmet (as shown in Figure 1), and takes the form of a recess around the cap in the case of a helmet without a chin guard (as shown in Figure 4).

[0020] The cap 2 has sheets arranged on both sides near the area of the user's ears, which are adapted to accommodate the corresponding anchor pins 32 of the visor assembly 3, and the assembly is adapted to rotate on the cap 2 to open and close the opening 23.

[0021] In one embodiment, the visor assembly 3 is attached to the cap 2.

[0022] In a further embodiment, the visor assembly 3 is removable from the cap 2, for example, to exchange it with a different visor assembly in order to adapt the helmet 1 to a specific lighting situation.

[0023] The visor assembly 3 has a variable transparent lens assembly 4 that can be used truly effectively and comfortably.

[0024] In one embodiment, the lens assembly 4 is directly attached to the cap 2.

[0025] In another embodiment, the visor assembly 3 has a frame 31 that can be engaged with the cap 2 and is adapted to support the lens assembly 4. Thus, in this embodiment, the frame 31 is applied to the lens assembly 4, particularly the structural lens 41, and the frame 31 at least partially follows the outer periphery of the structural lens 41.

[0026] In the embodiments of FIGS. 1 and 4, the visor assembly 3 has a frame 31 that can be engaged with the cap 2 by a pair of anchor pins 32 that can be inserted into a suitable seat of the cap 2.

[0027] In the embodiment of FIG. 1, the frame 31 completely surrounds the lens assembly 4 of the visor 3. In the embodiment, the cap 2 also has a fixed or spring-up jaw guard to cover the user's jaw. In the embodiment, the helmet 1 is a full-face helmet.

[0028] In the embodiment of FIG. 4, the frame 31 only partially surrounds the lens assembly 4 of the visor 3. In fact, as can be seen, there is no frame 31 at the lower part of the lens assembly 4. In the embodiment, the cap 2 has no jaw pad to cover the user's jaw, and thus the jaw remains uncovered. In the embodiment, the helmet 1 is an open or non-full-face helmet.

[0029] The lens assembly 4 has a structural lens 41 or an outer lens. The structural lens 41 is at least partially transparent. The lens may be formed from a transparent material without the addition of pigment, resulting in a light transmittance close to 100%. Alternatively, it may be formed by using a material, or a combination of pigment, material, and surface treatment, in a manner that non-uniformly filters out some of the invisible light and radiation, possibly across the entire spectrum, in order to obtain optimal visibility under different environmental conditions.

[0030] In the case of frame 31, the structural lens 41 is attached to frame 31 by means of, for example, interlocking, bonding, using magnets, or interposing a double-sided adhesive film.

[0031] Preferably, the structural lens 41 is formed from a plastic material such as polycarbonate or polyamide.

[0032] In embodiments intended for use under specific lighting conditions, the structural lens 41 may be pigmented to adjust the absorption spectrum, and specifically in this case, the structural lens 41 may also be pigmented, for example, by increasing the contrast, to adjust the contrast under specific lighting conditions.

[0033] As shown in Figure 8, the structural lens 41 has an outer surface 411 and an inner surface 412.

[0034] Preferably, the outer surface 411 of the structural lens 41 is treated with a coating such as scratch-resistant and / or mirror-finish and / or anti-reflective and / or multilayer coating.

[0035] The lens assembly 4 has a liquid crystal film 43 (hereinafter referred to as LC film) having an outer surface 431 facing the structural lens 41 and an inner surface 432 facing it.

[0036] LC film 43 is a GH (guest-host) liquid crystal type. In this type of LC film, dichroic pigments are dispersed in the liquid crystal matrix. A magnetic field drives the orientation of the liquid crystals, which in turn drives the orientation of the pigments. Normally, in the "active" state, the crystals are arranged in a helical pattern and the pigments are arranged in a plane parallel to the film surface, but in the "inactive" state, the crystals and pigments are arranged perpendicular to the film surface.

[0037] Preferably, the LC film 43 has a visible light transmittance of at least 60% in its brightest state and up to 40% in its darkest state. For example, the LC layer may have a transparency of about 30% in its darkest state and about 70% in its brightest state.

[0038] The LC film 43 is controlled by the electronic board 5, which will be described later, and generates a signal whose intensity increases in response to an increase in ambient light.

[0039] Preferably, the LC film 43 is attached to the back surface, i.e., the inner surface 412 side, of the structural lens 41, preferably using an optically transparent adhesive (OCA).

[0040] For example, in one embodiment shown in Figure 1, the structural lens 41 has a cylindrical curvature, that is, it is curved uniaxially. Advantageously, this shape allows the LC layer 43 to be laminated onto the structural lens 41 in an optimal manner.

[0041] In one embodiment, the shape of the LC film 43 is included in the shape of the structural lens 41. Therefore, the portion of the shape of the structural lens 41 that is not covered by the shape of the LC film 43 defines the free edge 413. Advantageously, this configuration avoids contact between the LC film 43 and the seal gasket 49, as shown in Figure 7. In an example where the visor assembly 3 does not have a frame, the free edge of the structural lens 41 not covered by the LC film 43 is at least partially covered by the cover layer. In an example where the visor assembly 3 has a frame, the free edge of the structural lens 41 not covered by the LC film 43 is at least partially covered by the frame.

[0042] In one embodiment shown in Figure 6, the structural lens 41 has a recess formed on its inner surface 412, where an LC film 43 is placed, and the LC film is embedded in the structural lens 41. In this embodiment, the free edge 413 of the structural lens 41 is at least partially covered by a cover layer 414. Therefore, when the cover layer 414 is applied to the structural lens 41, the area of ​​the field of view outside the LC film 43 is blocked.

[0043] Preferably, an anti-fog treatment and / or anti-reflective treatment, or a substantial additional layer having an anti-fog treatment and / or anti-reflective treatment, may be applied to the interior of the LC film 43, i.e., the inner surface 432 side.

[0044] In the embodiment shown in Figure 8, the lens assembly 4 has an anti-polarization film 42 positioned on the outside of the LC film 43, i.e., on the outer surface 431. The anti-polarization film 42 is positioned between the structural lens 41 and the LC film 43.

[0045] Preferably, the depolarization effect is achieved by a birefringent film in which the wave phase difference between the two optical axes exceeds 1500 nm.

[0046] The visor assembly 3 has an electronic board 5 adapted to control the LC film 43. The electronic board 5 has a photovoltaic cell and an electronic circuit powered by the photovoltaic cell. In one embodiment, the electronic board 5 has one photovoltaic cell located on the front and center, and two integrated circuits located on the rear, side, and left and right of the photovoltaic cell. Preferably, the photovoltaic cell operates simultaneously as a sensor for the amount of light in the environment and as a power source for the LC film. In fact, the more light that hits the photovoltaic cell, the more power is generated by the photovoltaic cell, and as a result, more power is supplied to the LC film, making the LC lens darker.

[0047] Preferably, the response curve between the input signal and the output signal from the electronic board 5 may be modified according to the user's needs.

[0048] Advantageously, the photovoltaic cell is located near the structural lens 41 and therefore receives more light. Specifically, the electronic board 5 containing the photovoltaic cell is located behind the structural lens 41, and the photovoltaic cell faces the structural lens 41.

[0049] Selectively, the structural lens 41 has a multilayer mirroring process.

[0050] The electronic board 5 is positioned internally relative to the structural lens 41. Advantageously, since the photovoltaic cell receives filtered light from the structural lens, it responds to the same components of ambient light received by the user's eye, after subtracting the intervention of the LC film.

[0051] The electronic board 5 is positioned in a compartment 33 located outside the perimeter defined by the front opening 23 of the cap 2, so that when the visor 3 is lowered, the electronic board 5 is outside the perimeter of the opening 23 and does not cause a significant reduction in the user's field of view. Therefore, advantageously, the photovoltaic battery is positioned in an area of ​​the user's field of view that is already obscured by the cap 2 of the helmet 1.

[0052] Preferably, the compartment 33 is sealed, i.e., leak-proof, to protect the electronic board 5. The board may, alternatively or additionally, be protected by a protective coating or embedded in resin.

[0053] In the frameless embodiment (Figure 6), the compartment 33 is created between the structural lens 41 and the rear protective shell.

[0054] In the framed embodiment (Figures 2, 3, 5), compartment 33 is located at the top of the frame.

[0055] In one embodiment, the helmet 1 includes a battery capable of supplying more power to the electronic board 5. In some cases, this battery may be used to power other electronic devices such as conventional or bone conduction audio systems, intercoms, "head-up" or conventional displays, signal lights, emergency call systems, cameras, or sensors.

[0056] Preferably, the cap 2 has a photovoltaic sheet that is at least partially positioned on the outside of the outer shell 21. Preferably, the photovoltaic sheet is a flexible sheet that deforms to conform to the curvature of the cap 2. Preferably, the photovoltaic sheet is connected to a battery.

[0057] Therefore, in summary, the protective helmet 1 for sports or motorized vehicles according to the present invention has the following:

[0058] - Protective cap 2 that protects at least a portion of the user's skull when wearing the helmet

[0059] - A structural lens 41 that is at least partially transparent.

[0060] - GH-type LC film 43 placed inside the structural lens 41

[0061] - A polarizing film 42 is placed between the structural lens 41 and the LC film 43.

[0062] The anti-polarizing film eliminates interference between the LC43 layer and the internal stress present within the structural lens 41, resulting in a comfortable and uniform field of view.

[0063] Advantageously, the protective helmet 1 for sports or motorized vehicles according to the present invention features a visor with variable transparency that is truly effective and comfortable to use.

[0064] Those skilled in the art will understand that modifications can be made to the above-described apparatus to meet incidental needs, and that all such modifications fall within the scope of protection defined by the following claims.

Claims

1. A protective helmet (1) for the practice of sports activities or the use of motorized vehicles, It has a cap (2) with a front opening (23) in the user's eye area, which is closed by a visor assembly (3), The visor assembly (3) is - At least one structural lens (41) that is at least partially transparent, - A guest-host type liquid crystal film (LC film) (43) is positioned behind the structural lens (41) and is adapted to change the transparency level. - At least one power source for supplying power to the LC film (43), - comprising at least one depolarizing layer (42) disposed between the structural lens (41) and the LC film (43), A protective helmet (1) in which the structural lens (41) is formed from a plastic material.

2. The protective helmet (1) according to claim 1, wherein the LC film (43) has at least 60% visible light transmittance in the brightest state and up to 40% visible light transmittance in the darkest state.

3. The protective helmet (1) according to claim 1, wherein the power supply that supplies power to the LC film (43) is connected to an electronic board (5) that controls the LC film (43) and generates a signal whose intensity increases in response to an increase in ambient light.

4. The electronic board (5) is characterized by the response curve between the input signal and the output signal, The protective helmet (1) according to claim 3, wherein the response curve is modifiable according to the user's needs.

5. The protective helmet (1) according to claim 3, wherein the electronic board (5) is positioned outside the periphery defined by the opening (23) of the cap (2) so as not to obstruct the user's field of view.

6. The protective helmet according to claim 1, wherein the structural lens (41) has a multilayer mirroring treatment.

7. The structural lens (41) and the LC film (43) each have their own shape. The shape of the LC film (43) is housed within the shape of the structural lens (41), The protective helmet according to claim 1, wherein the free edge (413) of the structural lens (41) that is not covered by the LC film (43) is at least partially covered by a cover layer (414) or a frame (31).

8. The visor assembly (3) has a frame (31) that supports the structural lens (41) and is fitted to secure it to the cap (2). The protective helmet (1) according to claim 1, wherein the frame (31) is at least partially along the periphery of the structural lens (41).

9. The aforementioned cap (2) is A rigid outer shell (21) and a foldable inner shell (22), A photovoltaic plate positioned at least partially outside the outer shell (21), It has, The protective helmet (1) according to claim 1, wherein the plate is connected directly or via a battery to the power supply for supplying power to the LC film (43).

10. The aforementioned cap (2) is A rigid outer shell (21) and a foldable inner shell (22), Bone conduction audio system and A protective helmet (1) according to claim 1, having the following features.

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