Protection device for eyes with variable transparency

Abstract

The protection device (1) for eyes according to the present invention comprises: an at least partially transparent structural lens (3) with at least one liquid crystal layer (8) with variable transparency applied; a photovoltaic cell (51) for activating the liquid crystal layer, frontally covered by an at least partially transparent element (3,31). Such device is characterized in that the at least partially transparent element (3,31) has a covering area (91) with mirroring treatment (9) in front of the photovoltaic cell (51), and the structural lens (3) has a vision area (90) devoid of mirroring treatment (9) and / or with mirroring treatment with a lower reflected light percentage than the covering area (91). This device is high in aesthetic impact due to the presence of mirroring treatment covering at least the photovoltaics, which is slightly or not at all visible to an outside observer.

Description

"PROTECTION DEVICE FOR EYES WITH VARIABLE TRANSPARENCY"DESCRIPTION

[0001] The present invention relates to a protection device for eyes with variable transparency according to the situations of use and with a high aesthetic impact .

[0002] In many conditions , especially outdoors , it is necessary to protect the eyes from particles , wind, ultraviolet rays , excess sunlight , etc . While mechanical and ultraviolet protection are mostly easy to implement , protection from excess sunlight with regard to visible radiation is complex, since the optimal level of protection varies depending on the user' s situation .

[0003] For this reason, at the regulatory level , five categories of solar filters have been introduced, each suitable for speci fic situations . However, it is obviously not practical to carry five di f ferent pairs of glasses or lenses , and to change them from time to time depending on the speci fic situation .

[0004] Photochromic lenses have therefore been developed that react to ultraviolet rays by reducing their transmittance by means of a chemical reaction . These lenses also have some drawbacks : they are very slow, they react mostly to ultraviolet radiation and not to visible radiation, and they are strongly influenced by temperature .

[0005] Electrochromic lenses have also been developed that are capable of modi fying their transmittance by means of an electronic control . These lenses , while faster than photochromatic lenses , are still quite slow . Furthermore , these lenses require a control for a change of state , and each change of state involves a fair energy consumption . Therefore , electrochromic lenses require a power supply battery that is bulky and heavy when incorporated into a typical protection device such as a classic pair of sunglasses .

[0006] Finally, liquid crystal lenses have been developed which are the fastest in modi fying their transmittance . The document US 6 433 913 shows an example of protective liquid crystal eyewear . Some liquid crystal lens solutions have been shown to be ef fective in compensating for sudden changes in lighting that a user encounters frequently in daily li fe or in speci fic activities . For example , the applicant has filed the patent application WO2023047271A1 relating to GH liquid crystal protective eyewear .

[0007] The use of liquid crystal lenses is very ef fective when combined with a photovoltaic power cell that allows the presence of a power supply battery to be avoided . It should be noted that , in addition to acting as a power supply, the photovoltaic cell may also act as a sensorfor activating the lens . It is also pos sible to use the photovoltaic cell only as a power supply, and to provide a separate sensor for activating the lens .

[0008] Generally, the best liquid crystal lens solutions that use photovoltaic cells as a power supply require the presence of relatively bulky solar cells , with surfaces on the order of a few square centimeters . Such cells , precisely because of their si ze , may strongly influence the appearance of the protection device to the extent that they severely limit the public acceptance of this new technology, especially i f they are devices designed for everyday li fe . In fact , a classic pair of sunglasses , in order to appeal to the public, must have a certain aesthetic level .

[0009] The obj ect of the present invention is to obtain a protection device for eyes of the variable transparency type , in order to always be ef fective in every situation of use , and wherein the presence of the photovoltaic cell is slightly or not at all visible to an outside observer, in order to have a high aesthetic impact .

[0010] This obj ect is achieved by means of a protection device according to claim 1 . The dependent claims disclose further advantageous embodiments of the invention .

[0011] The features and advantages of the protection deviceaccording to this invention will become apparent from the following description, given as a non-limiting example in accordance with the accompanying drawings , wherein :- Fig . 1 shows a protection device for eyes with variable transparency according to the present invention, configured as sunglasses ;Fig . 2 shows the protection device in Fig . 1 in an exploded view;- Fig . 3 shows the protection device in Fig . 1 in a top view in which a section plane A-A is highl ighted;Fig . 4 shows the protection device in Fig . 1 in a sectional view along the plane A-A and an enlargement thereof ;- Fig . 5 shows a protection device for eyes with variable transparency according to the present invention in a front view during use ;- Fig . 6 shows a series of geometric patterns ( denoted with the letters A to F) of a mirroring treatment applied to the protection device according to the present invention;- Fig . 7 shows a series of embodiments ( indicated with the letters A to D) of a protection device according to the present invention;- Fig . 8 is an exploded view of a protection device for eyes with variable transparency according to the presentinvention in a further exemplary embodiment .

[0012] With reference to the accompanying figures , a protection device for eyes with variable transparency, and in particular eyewear, according to the present invention has been indicated in its entirety with the reference numeral 1 .

[0013] The protection device 1 comprises a frame 2 adapted to support a lens assembly 6 comprising a structural lens 3 to which at least one liquid crystal layer 8 with variable transparency is applied on the inner s ide .

[0014] Preferably, the frame 2 completely surrounds the lens assembly 6 , as shown in Fig . 1 .

[0015] The frame 2 is made , for example , of a polymer material or of a polymer matrix composite material . Preferably, reinforcing materials , such as glass fiber, carbon fiber, glass or graphene microspheres , are added to the polymer matrix composite material . For example , the frame 2 is made of polyamide reinforced with glass or carbon fiber . In an alternative embodiment , the frame 2 is made of a lightweight metal material , such as aluminum, titanium, or magnesium alloys . Depending on the material chosen, the frame 2 is obtained by means of inj ection molding, alternatively, the frame 2 is produced by forging, die-casting, or sheet metal forming . Advantageously, the materials listed above make itpossible to obtain a frame 2 that is suf ficiently rigid in order to avoid deformations of the lens group 6 during use , which deformations would be transmitted to the liquid crystal layer 8 thereby compromising the optical uni formity thereof .

[0016] The protection device 1 , when configured as eyewear, comprises two temples 13 provided with a hinge engagement 131 that allows assembly to the frame 2 , for example by interlocking ( Fig . 8 ) or by means of small screws 132 ( Fig . 2 ) . The temples 13 may be closed in abutment one on top of the other in order to reduce the bulk of the eyewear when not in use .

[0017] The structural lens 3 is assembled to the frame 2 by interlocking in a bevel present inside the frame 2 . In an alternative example , the structural lens 3 is assembled to the frame 2 by means of a double-sided adhesive tape , for example having a thickness between 0 . 5 mm and 3 mm . In yet another alternative example , the structural lens 3 is assembled to the interlocking frame 2 inside a slot provided inside the frame 2 .

[0018] Preferably, the structural lens 3 is made of polyamide or polycarbonate with a thicknes s between 0 . 8 and 3 mm .

[0019] Preferably, the structural lens 3 has an anti- reflective and / or anti-scratch and / or hydrophobic and / oroleophobic treatment.

[0020] In an exemplary embodiment, the structural lens 3 has a recess in which the photovoltaic cell 51 is partially or entirely housed.

[0021] In an exemplary embodiment, the structural lens 3 is provided with one or two photochromic films.

[0022] In an exemplary embodiment, the structural lens 3 has pigmentations in order to increase the contrast in devices intended for specific uses.

[0023] The frame 2 is provided with a seat or recess 4 in which at least one photovoltaic cell 51 is housed, which acts, preferably, both as an energy source for the liquid crystal layer 8 and as a sensor for activating the liquid crystal layer 8. Preferably, an entire circuit board 5 including the photovoltaic cell 51 is housed in the seat 4. The circuit board 5 is the control module of the liquid crystal layer 8. The at least one liquid crystal layer 8 is connected to the circuit board 5, comprising the photovoltaic cell 51, by means of a flexible printed circuit (FPC) 52.

[0024] Advantageously, the recess 4 is positioned in the front, upper, central part of the frame 2, as seen in Fig. 2, so as not to annoyingly reduce the visual field of the user.

[0025] In an exemplary embodiment, shown in Fig. 2, thestructural lens 3 is arranged so as to close the recess 4 in front of the circuit board 5 , which is protected at the rear by the walls of the recess 4 formed in the frame 2 . In a further exemplary embodiment , shown in Fig . 8 , a cover 31 is arranged so as to close the recess 4 in front of the circuit board 5 , which is protected at the rear by the walls of the recess 4 formed in the frame 2 . Advantageously, both of these solutions provide mechanical and chemical protection to the circuit board 5 . Thus , in the example in Fig . 2 , the structural lens 3 also forms the cover of the photovoltaic cell 51 , while in the example in Fig . 8 , a cover 31 , separate from the structural lens 3 , is used to cover the photovoltaic cell 51 . In the example in Fig . 2 wherein the structural lens 3 also forms the cover of the photovoltaic cell 51 , the liquid crystal layer 8 is preferably not interposed between the structural lens 3 and the photovoltaic cell 51 .

[0026] The structural lens 3 or, where present , the cover 31 is at least partially transparent to al low light to reach the photovoltaic cell 51 . The term "at least partially transparent" refers to an element capable of allowing at least 50% of the light to pass through .

[0027] Thus , in the protection device 1 , the photovoltaic cell 51 is frontally covered by an at least partiallytransparent element , be it the structural lens 3 or the cover 31 . In the protection device 1 , the at least partially transparent element covering the photovoltaic cell 51 has a mirroring treatment 9 .

[0028] The mirroring treatment 9 increases the percentage of light reflected by the outer surface of the structural lens 3 . Preferably, the percentage of light reflected by the mirroring treatment 9 is between 5% and 40% . Advantageously, the presence of the mirroring treatment 9 allows the photovoltaic cell 51 to be hidden from the view of an outside observer, even when there are no bright or light elements that are reflected by the at least partially transparent element .

[0029] Preferably, the mirroring treatment 9 is present only on some areas of the surface of the at least partially transparent element , as seen from the various exemplary embodiments of Fig . 7 .

[0030] The protection device 1 therefore has an at least partially transparent element 3 , 31 having a covering area 91 , positioned at least partially in front of the photovoltaic cell 51 , which is provided with a mirroring treatment 9 with a certain reflected light percentage . Furthermore , the structural lens 3 has at least one vision area 90 , intended for the user' s view, which is devoid of a mirroring treatment ( as in examples A, B andC of Fig . 7 ) and / or is provided with a mirroring treatment with a lower reflected light percentage than the reflected light percentage of the mirroring treatment of the covering area 91 ( as in example D of Fig . 7 ) . Advantageously, the presence of the covering area 91 allows the photovoltaic cell 51 to be hidden from the view of an outside observer, while still allowing a large part of the light to reach the photovoltaic cell 51 for the proper functioning of the liquid crystal layer 8 .

[0031] In a preferred solution, the mirroring treatment 9 at least partially covers the photovoltaic cell 51 but not the areas in front of the user' s eyes ( as in examples A, B and C of Fig . 7 ) . Preferably, the mirroring treatment 9 does not cover at least the area within a radius R of 13 mm from the proj ection point P, in frontal view, of the centers of the pupils of the user' s eyes , as shown in Fig . 5 . Advantageously, this configuration allows the use of strong mirroring treatments to cover the photovoltaic cell 51 without compromising the optical quality of the protection device 1 in those areas that are most relevant for the correct vis ion o f the user .

[0032] The element that is at least partially transparent , be it the structural lens 3 or the cover 31 , has an inner surface facing the photovoltaic cell 51 , and an opposite outer surface . A mirroring treatment is applied to one ofthese surfaces . Preferably, the mirroring treatment is applied to the outer surface .

[0033] Preferably, the mirroring treatment 9 is opaque , satin, or in any case non-specular .

[0034] The mirroring treatment may be multi-layer or single-layer, neutral or colored ( e . g . silver, gold, red, blue , green, pink, purple ) . The mirroring treatment is for example a multilayer treatment with a reflection spectrum centered on the infrared wavelengths .

[0035] The mirroring treatment 9 is superimposed, for example , on another mirroring treatment , thereby increasing its strength in certain areas . For example , as shown in the embodiment variant D in Fig . 7 , a stronger mirroring treatment at least partially positioned in front of the photovoltaic cell 51 is superimposed on a light mirroring treatment . Advantageously, therefore , the mirroring treatment present at the photovoltaic cell 51 ( covering area 91 ) has a greater reflection than any other mirroring treatments present at the area in front of the user' s eyes (vision area 90 ) , so as to hide said cell without compromising the correct vision through the eyewear .

[0036] Preferably, the mirroring treatment 9 is present on the surface of the at least partially transparent element 3 , 31 according to an established design . Preferably, themirroring treatment 9 comprises, or is, a design or a pattern of the full / empty type, wherein the mirroring treatment is present in the "full" area (p) and the mirroring treatment is not present in the "empty" area (v) . Advantageously, a mirroring treatment with a pattern of the full / empty type further increases the amount of light capable of reaching the photovoltaic cell 51.

[0037] Said pattern may be composed of any linear, radial, square-grid, triangular, or hexagonal repetition of any geometric shape. Some possible examples of this pattern are shown in the variant embodiments indicated with the letters A to F in Fig. 6:A: point-shaped mirroring treatment, with uniform circular points;- B: mirroring treatment background with uniform circular points devoid of treatment;C: point-shaped mirroring treatment, with circular points decreasing towards one side;D: point-shaped mirroring treatment, with hexagonal points decreasing towards one side;- E: mirroring treatment background with hexagonal points devoid of treatment increasing towards one side;F: point-shaped mirroring treatment, with hexagonal points decreasing towards the center.

[0038] The mirroring treatment 9 with a pattern of thefull / empty type is characteri zed by a surface coverage factor given by the ratio between the mirroring area (" full" ) and the total area of the covering area 91 between 1 / 8 and 1 / 2 .

[0039] Preferably, said covering factor varies depending on the region of the treatment . Preferably, said covering factor varies in space in a gradual manner, being greater at the photovoltaic cell 51 than at the area in front of the user' s eyes .

[0040] As mentioned above , inside the structural lens 3 there is at least one liquid crystal layer or film 8 positioned in the area in front of the user' s eyes . In one embodiment , there is a single structural lens 3 with a laminated liquid crystal layer 8 covering the two areas in front of the user' s eyes . In a further example , there is a single structural lens 3 with a laminated pair of liquid crystal layers 8 as in Fig . 2 . In a still further embodiment example , such as example B in Fig . 7 , there is a pair of distinct structural lenses 3 , each with its own liquid crystal layer 8 ; in such an example , the cover 31 is present .

[0041] The liquid crystal layer 8 is surrounded by a peripheral seal 81 which allows the liquid crystals to be enclosed and sealed in a compartment composed of two substrates and said seal . Preferably, the mirroringtreatment 9 also covers the seal 81 , making it not very evident from the outside , as shown in Fig . 5 .

[0042] Preferably, the seal is covered, on the inner side , by the frame 2 . Preferably, the frame 2 also covers any gap present between the liquid crystal layer 8 and the frame 2 .

[0043] Preferably, the liquid crystal layer 8 is made with crystals of the of Guest-Host type , wherein a matrix of liquid crystals guides the orientation of dichroic pigments that change their orientation thereby causing di f ferent levels of transparency . In the absence of an electrical field, the pigments are arranged perpendicular to the substrates by virtue of a suitably formed alignment layer . In the presence of an electric field, the liquid crystal molecules , and consequently the dichroic pigments , are arranged parallel to the substrates , reducing the transmittance of the liquid crystal layer .

[0044] In the case of using a liquid crystal layer 8 of the Guest-Host type , at least one depolari zing film is preferably arranged between the liquid crystal layer 8 and the structural lens 3 . Advantageously, this configuration makes it possible to eliminate interference between the liquid crystal layer and internal stresses often present within the structural lens , especially i fsuch structural lens is made by inj ection molding .

[0045] In an alternative example , the liquid crystal layer 8 is a crystal of the "twisted nematic" type . In thi s type of layer, liquid crystals exhibit birefringence characteristics , and this allows suitably configured crystals to modi fy the polari zation of the light , allowing it to pass through two non-parallel polari zed filters . In the absence of an electrical field, the liquid crystals change orientation and stop guiding the polari zation in this way; it therefore happens that the second polari zing filter blocks almost all of the light that has passed through the first .

[0046] When using a liquid crystal layer 8 of the "twisted nematic" type , preferably the two polari zing filters present internally and externally to the liquid crystal layer are not totally polari zing, so as to have a theoretical transmittance of more than 50% in the deactivated state and signi ficantly greater than 0% in the activated state . Typically with the layer activated, the transmittance is between 4 % and 15% .

[0047] As shown in Fig . 2 , the liquid crystal layer 8 is connected to the circuit board 5 , comprising the photovoltaic cell 51 , via a flexible printed circuit ( FPC ) . Preferably, the mirroring treatment 9 also covers the engagement area between the liquid crystal layer 8and the flexible printed circuit , making it not very evident from the outside , as shown in Fig . 5 and in examples B and C of Fig . 7 .

[0048] A cover 7 , e . g . , made as a pad print or other type of print , is preferably applied inside the structural lens 3 , said cover being adapted to hide the engagement areas between the liquid crystal layer 8 and the flexible printed circuit 52 . Advantageously, such solution further hides the flexible printed circuit to make it non-visible in transparency through the mirroring treatment .

[0049] Preferably, the frame 2 and / or the photovoltaic cell 51 and / or the flexible printed circuit board 52 and / or the seals 81 are dark or black in color . Advantageously, this solution further decreases the visibility of these elements through the mirroring treatment .

[0050] In other embodiments of the present invention, the photovoltaic cell 51 is independent of the circuit board 5 and is connected thereto by means of a flexible printed circuit or else by means of wiring .

[0051] In other embodiments of the present invention, an activation sensor of the liquid crystal layer 8 is also provided, which sensor is smaller in si ze than that of the photovoltaic cell 51 and acts only as a power supply .

[0052] Preferably, the photovoltaic cell 51 is monocrystalline , or amorphous , or organic, or any otherknown type of solar cell . Preferably, the photovoltaic cell 51 is monocrystalline and flexible in such a way as to follow the curvature of the structural lens 3 or of the cover 31 . For example , the monocrystalline photovoltaic cell 51 may be made with silicon wafers with a thickness of 50 pm or less .

[0053] Preferably, the photovoltaic cell 51 is laminated to the structural lens 3 , or to the cover 31 , by means of optical adhesive .

[0054] In one example , the term "photovoltaic cel l" refers to a panel that comprises a plurality of solar cells arranged in series . In a further example , the term "photovoltaic cell" refers to a plurality of panels , each comprised of a plurality of solar cells arranged in series . In both examples , the total number of solar cells present is preferably between 6 and 16 . In one example , said panel may be obtained by assembling multiple photodiodes on a rigid or flexible circuit board 5 .

[0055] Preferably, the circuit board 5 is connected to the flexible printed circuit via a small connector or by welding .

[0056] Where there is a pair of liquid crystal layers 8 , there may be two separate flexible printed circuits 52 as in Fig . 2 , or a single flexible printed circuit connected to both liquid crystal layers 8 .

[0057] To conclude , Fig . 7 shows some embodiments of the protection device 1 according to the present invention :- A: the covering area 91 with mirroring treatment 9 is present only in front of the photovoltaic cell 51 and the vision area 90 is completely devoid of mirroring treatment ;- B : the covering area 91 with mirroring treatment 9 is present both in front of the photovoltaic cell 51 and in front of the engagements between the liquid crystal layer 8 and the flexible printed circuit 52 , while the vision area 90 is completely devoid of mirroring treatment ;- C : the covering area 91 with mirroring treatment 9 is present in front of the photovoltaic cell 51 , in front of the engagements between the liquid crystal layer 8 and the flexible printed circuit 52 and also in front of the seals 81 of the liquid crystal layer 8 , while the vision area 90 is completely devoid of mirroring treatment ;- D : the covering area 91 with mirroring treatment 9 is present in front of the photovoltaic cell 51 , while the vision area 90 has a mirroring treatment with a lower reflected light percentage than the reflected light percentage of the mirroring treatment of the covering area 91 .

[0058] Innovatively, the protection device for eyes according to the present invention has a variabletransparency in order to be always ef fective in every situation of use and a high aesthetic impact due to the presence of the mirroring treatment to cover at least the photovoltaic, which is slightly or not at all visible to an outside observer .

[0059] It is understood that a person skilled in the art , in order to meet contingent needs , could make modi fications to the device described above , all of which are contained within the scope of protection as defined by the following claims .

Claims

CLAIMS1. Protection device (1) for eyes with variable transparency, having a frame (2) suitable for supporting a lens group (6) comprising:- at least one structural lens (3) which is at least partially transparent, to which at least one liquid crystal layer (8) with variable transparency is applied;- at least one photovoltaic cell (51) , or a sensor, to activate the liquid crystal layer (8) , frontally covered by an at least partially transparent element (3,31) ; characterized in that said at least partially transparent element (3,31) has a covering area (91) provided with a mirroring treatment (9) , arranged at least partially in front of the photovoltaic cell (51) ; and in that said structural lens (3) has at least one vision area (90) intended for the user's view, devoid of the mirroring treatment (9) and / or provided with a mirroring treatment with a lower reflected light percentage than the covering area (91) .

2. Protection device (1) according to claim 1, wherein said at least partially transparent element is:- said at least one structural lens (3) , or- a cover (31) which is distinct from the structural lens(3) .

3. Protection device (1) according to claim 1 or 2, wherein said photovoltaic cell (51) is both the sensor for activating the liquid crystal layer (8) and an energy source for powering the liquid crystal layer (8) .

4. Protection device (1) according to any one of the preceding claims, wherein said mirroring treatment (9) has a glazed or opaque or non-specular reflection.

5. Protection device (1) according to any one of the preceding claims, wherein said at least partially transparent element is a structural lens (3) provided with two vision areas (90) lacking the mirroring treatment (9) , each occupying a circle having a radius of at least 13mm.

6. Protection device (1) according to any one of the preceding claims, wherein said at least one liquid crystal layer (8) is provided with a peripheral seal (81) , and wherein said covering area (91) provided with a mirroring treatment (9) also covers said peripheral seal (81) .

7. Protection device (1) according to any one of the preceding claims, wherein said mirroring treatment (9) comprises a pattern of the full / empty type in which a mirroring is present in the "full" area and the mirroring is not present in the "empty" area .

8. Protection device (1) according to claim 7, wherein in said pattern the ratio between "full" and total surface of the covering area (91) is between 1 / 8 and 1 / 2.

9. Protection device (1) according to any one of the preceding claims, wherein said at least one liquid crystal layer (8) is of the Guest Host type.

10. Protection device (1) according to claim 9, wherein a depolarizing layer is present between said at least one liquid crystal layer (8) and said at least one structural lens ( 3 ) .

11. Protection device (1) according to any one of the preceding claims, wherein said photovoltaic cell (51) consists of a semi-flexible, monocrystalline photovoltaic panel, which follows a curvature of said structural lens

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