The present invention refers to a lens with an improved aesthetic matt appearance and to the related sunglass.

Background Art

In the field of lens for sunglasses, some attempts were made in order to obtain an aesthetic matt appearance to the external lens. For obtaining this effect, it is necessary to increase the diffuse reflection while suppressing the specular reflection. This action will be perceived from an aesthetic point of view by an observer as matt and bright looking eyewear.

In this context, EP 1 887 414 A1 in the name of Stephen Dillon aims to increase the diffuse reflection while suppressing the specular reflection through the presence of a diffuse reflecting form texture positioned between the two external light transmitting lens elements. This texture is fabricated during the injection molding process of the first light transmitting lens element and applying in a second step a reflecting medium which is only partially reflecting, preferably applied by chemical vapor deposition.

That diffuse reflecting form texture is somehow pixeled with the following parameters:

- spacing between pixel peaks of 23 to 178 pm,

- each pixel has a randomly oriented average slope of a few degrees (0.75° to 6.5°), and

- peak to Valley roughness Rq is stated as 0.15 to 0.635 pm.

As stated at paragraphs 0014, 0023 and 0029, the refractive index of the various materials (therefore the group constituted by the first lens and the second lens element, and eventually the adhesive interface) should be equal or as similar as possible to avoid refraction between the lens layers. Without the reflective medium in between the lens layers no optical effect would be perceivable, thus no matt action would be perceived by an observer. So only the shape of the diffuse reflecting form texture together with the reflecting medium are defining the diffusion characteristic of this lens.

The Applicant has observed that, the matt appearance as disclosed in the above solution is not so good as promised. An observed is able to discern the matt effect looking at the sunglass from a very close point of view only.

These drawbacks are due mainly because a good matt appearance is obtained when the space between pixel peaks is very reduced.

The Applicant has noted that since Dillon’s solution is formed by injection molding or cast process only, it is very difficult to make a texture with reduced space between pixel peaks. Moreover, these processes for making the form texture are very time-consuming and expensive.

Description of the Invention

In view of these problems, the Applicant has found an alternative way for obtaining an improved lens with more effective matt appearance saving time and costs with a solution able to realize a light diffusion layer with reduced space between the peaks, so obtaining a better aesthetic result.

Therefore, the present invention relates to a lens with an improved aesthetic matt appearance having the features of claim 1.

Another scope of the invention relates to a sunglass having the features of claim

10.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become better evident from the description of a preferred but not exclusive embodiment of a lens with aesthetic matt appearance, illustrated by way of an indicative, but not limitative example in the accompanying drawings in which:

- Figure 1 is a sectional view of a lens according to the present invention,

- Figure 2 is a scanning electron microscopic image showing spaces between peaks and valley of an internal light diffusion layer of the lens of Figure 1 ,

- Figure 3 is a front view of a sunglass according to the present invention with a complete matt appearance,

- Figure 4 is a front view of a sunglass according to the present invention with a partial matt appearance. Embodiments of the Invention

A lens with aesthetic matt appearance according to the present invention is indicated with reference number 1 in the annexed figures.

The lens 1 comprises a light-transmitting cover layer 2, facing the eye of a user wearing sunglasses, an external lens layer 3 and a light diffusion layer 4 positioned between the light-transmitting cover layer 2 and the external lens layer 3.

Preferably, the lens layer 3 comprises a front surface 31 and a back surface 32. The lens layer 3 may be made from a light-transmitting material, such as glass, resin, or the like. Moreover, the lens layer 3 may be added with an ultra-violet absorbent to protect against a ultra-violet light. Furthermore, the lens layer 3 may be made from a dyed light-transmitting material or dyed after it is made so as to provide the lens layer 3 with a desirable colour.

The light diffusion layer 4 is a coating, obtained by spraying a dispersion of light transmitting resinous microbeads, formed on the back surface 32 of the lens layer 3.

According to an embodiment, the light transmitting resinous microbeads are made from silane polymer. The light diffusion layer 4 may be formed according to the technique disclosed in US 6 620 454, the disclosure of which is incorporated herein by reference.

In this technique, a dispersion for forming the light diffusion layer 4 may be prepared by dispersing the light transmitting resinous microbeads in an organic solvent, such as isopropyl alcohol (IPA), butyl cellosolve (BCS), acetone, ethanol, and combinations thereof.

Thanks to the presence of the light transmitting resinous microbeads, the function of the light diffusion layer 4 is to diffuse the light impinging thereon to obtain a light reduction effect.

Advantageously, the sizes of the light transmitting resinous microbeads can be controlled within a specific range so as to obtain an optimum balance between the light transmittance and the light reduction.

As shown in figure 2, the coating 4 made by spraying the dispersion of light transmitting resinous microbeads cause the formation of a peaks- and- valleys surface wherein white and light-gray coloured portions of pixels form the peaks of the surface while black and dark-gray cloured portions of pixels form the valleys of the surface.

According to an embodiment, the peak-to-peak distance of the coating’s surface is comprised between 10 pm to 50 pm, preferably comprised between 15 pm to 30 pm.

According to a further embodiment, the thickness of the light diffusion layer 4 is less than 1 pm, preferably comprised between 0,5 pm to 1 pm. Advantageously, the thickness of the light diffusion layer 4 slightly varies around 0,8 pm with a tolerance of ± 0, 1/0,2 pm.

According to a further embodiment, the light transmitting resinous microbeads have a size not larger than 100 pm such that the lens layer 2 has a haze not larger than 3% and a transmittance not less than 3%. In certain embodiments, the size of the light transmitting resinous microbeads ranges from 10 pm to 80 pm, preferably from 30 pm to 50 pm.

In addition, the light diffusion layer 4 has a surface roughness ranging from 40 nm to 500 nm. In certain embodiments, the surface roughness of the light diffusion layer 4 ranges from 100 nm to 200 nm, preferably 180 nm.

According to an embodiment, the lens 1 further comprises two anti-reflective layers 5, 6. One of the anti-reflective layers 5 is formed on the back surface 22 of the light-transmitting cover layer 2, the other of the anti-reflective layers 6 is formed on front surface 31 of the lens layer 3.

Preferably, the anti-reflective layers 5, 6 may be formed via vacuum coating, chemical deposition, chemical vapor deposition, dip coating, or other techniques well known in the art.

The anti-reflective layers 5, 6 may be made from a material selected from the group consisting of: magnesium fluoride (MgF2), silicon dioxide (Si02), titanium oxide (TiOx, x £ 2), niobium oxide (Nb205), tantalum oxide (Ta203), aluminum oxide (A1203), and combinations thereof. The anti-reflective layers 5, 6 are provided for reducing the light reflection so as to enhance the light transmittance of the lens 1.

According to a preferred embodiment, the lens 1 does not comprise anti- reflective layers 5, 6. In this case, the reflective indexes of the light- transmitting cover layer 2, external lens layer 3 and light diffusion layer 4, according to the physical laws, must be diverse. As said before, since the light diffusion layer 4 is very thin, in the order of two wavelength of the visible light, and different refractive indexes, interference effects are present. Those effects can act like an anti-reflection or enhanced reflection coating. Thanks to the variable thickness of the light diffusion layer 4, these properties vary locally on the surface, thus a light beam may be reflected in different directions with different intensities causing an additional diffusive effect. Therefore, Applicant’ solution can work without the presence of reflecting mediums because of the different refractive indexes of the light diffusion layer 4.

According to another scope, the invention relates to a sunglass 10 comprising at least a lens 1 as shown in figure 3.

Preferably, the sunglass 10 comprises a frame configured to support:

- only one lens 1 , or

- two lenses 1.

The frame 11 comprises a pair of ear stems 12, 13 that support the lens 1 and a nosepiece 14 connected at the centre of the lens 1. It should be noted that the particular frame 11 can be of varying configurations and designs, and the illustrated embodiment shown in figure 3 is provided for exemplary purposes only. Preferably, the lens 1 which will be form part of the sunglass S is cut starting from a portion of a cylindrical surface lens.

According to an embodiment, the lens 1 which will be form part of the sunglass S is cut starting from a portion of a spherical surface lens.

According to another embodiment, the lens 1 which will be form part of the sunglass S is cut starting from a portion of a flat surface lens.

As shown in figure 3, the lens 1 of the sunglass 10 can have a complete matt appearance. However, according to another embodiment, spraying the light transmitting resinous microbeads to a predetermined area only of the external lens layer 3 it is possible to create various designs which causes the lens 1 having a partial matt appearance. In the example of figure 4, it is shown a sunglass 10 with a single lens 1 where the word “MIAMI” has a matt appearance, whilst the other part of the lens 1 has a glossy appearance. The embodiments of the lens described above are potentially infinite and obviously an expert in the field, in order to satisfy contingent and specific needs, will be able to make numerous modifications and variations, all of which nevertheless contained within the scope of protection of the invention, as defined by the following claims.