Selective tinting method

Abstract

A selective dyeing method is used for dyeing a substrate, selectively within a first exposed surface portion of said substrate. For this purpose, the substrate consists of a material that is impervious to a dye with the exception of the first portion of the exposed surface. In particular, the impervious material can form a layer which covers a base portion of the substrate in a second portion of the exposed surface. The substrate is heated such that the dye penetrates a pervious material which constitutes the first portion of the exposed surface. The method is particularly useful for eliminating light diffused by the walls of a multilayer structure which is supported by means of ocular glass.

Claims

1. A transparent cellular component allowing a clear vision through said component and comprising: a transparent base substrate having an upper surface; a transparent first material formed on the upper surface of the base substrate; and a transparent second material formed on the first material, wherein the first material has a gelation or softening temperature that is greater than a gelation or softening temperature of the second material, the first material is more impermeable to dye at a temperature below the gelation or softening temperature of the first material than is the second material above the gelation or softening temperature of the second material, and the second material is more permeable to the dye at a temperature above the gelation or softening temperature of the second material than is the first material below the gelation or softening temperature of the first material, such that at a dyeing temperature between the gelation or softening temperature of the first material and the gelation or softening temperature of the second material, presence of the dye will simultaneously dye the second material and while not dyeing the first material.

2. The transparent cellular component of claim 1, wherein the first material forms a transparent layer having opposite first and second sides, the second side facing the base substrate, and the second material forms a network of walls arranged on the first side of the transparent layer, the walls extending perpendicularly to the upper surface of the base substrate.

3. The transparent cellular component of claim 1, wherein the second material incorporates dyes and the first material is without dyes.

4. The transparent cellular component of claim 3, wherein a distribution of said dyes inside the second material corresponds to a diffusion profile from a surface of said second material.

5. A transparent cellular component allowing a clear vision through said component and comprising: a transparent base substrate having an upper surface; a transparent first material supported by the upper surface of the base substrate and having opposite first and second sides, the second side facing the upper surface of the base substrate; and a transparent second material disposed on the first side of the first material, having walls extending perpendicularly to the upper surface of the base substrate, wherein the second material incorporate dyes in a distribution of said dyes inside the second material corresponding to a diffusion profile from a surface of said second material, and wherein the first material is without dyes.

6. The transparent cellular component according to claim 5, wherein the first material has a gelation or softening temperature that is greater than a gelation or softening temperature of the second material.

7. The transparent cellular component according to claim 5, wherein the second material is an organic material or a mineral-organic hybrid material, and the first material is a mineral material or a mineral-organic hybrid material.

8. The transparent cellular component according to claim 7, wherein the first material comprises silica, zinc oxide, tin-doped indium oxide, or a hybrid material incorporating silica, zinc oxide, or tin-doped indium oxide.

9. The transparent cellular component according to claim 5, wherein the second material comprises a photoresist resin.

10. The transparent cellular component according to claim 5, forming at least a portion of an eyeglass lens, a mask lens, an optical lens, a helmet visor, an aircraft window, or a glazing, or forming at least a portion of a multilayer structure configured to be applied onto an eyeglass lens, a mask lens, an optical lens, a helmet visor, an aircraft window, or a glazing.

11. The transparent cellular component according to claim 5, wherein the second material forms a network of walls disposed on the first side of the first material, walls of the network of walls extending perpendicularly to the upper surface of the base substrate.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) Other features and advantages of the invention will be apparent from the following description of a non-limiting example, with reference to the attached drawings in which:

(2) FIG. 1 is a cross-sectional view of a substrate to which a method of the invention can be applied;

(3) FIGS. 2a-2c are enlarged cross-sectional views of the substrate of FIG. 1, in several steps of a method of the invention; and

(4) FIG. 3 illustrates a specific application of the substrate of the above figures.

(5) For sake of clarity, the dimensions of the elements represented in these FIGS. do not correspond to actual dimensions or to actual dimension ratios. In addition, identical references indicated in different FIGS. denote identical elements.

DETAILED DESCRIPTION

(6) The invention is now described for illustrative purpose in the context of an ophthalmic application, but it is understood that it may be applied to other technical fields.

(7) The invention is particularly suitable for tinting a component forming a substrate, when this component is initially transparent and must remain transparent after having been tinted. In the context of the invention, transparent component is understood to mean an optical component which allows a user positioned on one side of the component to see distinctly, through this component, objects positioned on another side and at a distance from the component. In other words, an image of an object is formed on the retina of the user by the light propagated over a first non-zero distance between the object and the transparent component, then passes through the transparent component and is propagated over a second non-zero distance between the transparent component and the user's eye. To this end, the diffusion and/or diffraction of the light caused by the optical component must be sufficiently low so that the image of a point of the object, through the transparent component, appears as a point and not a diffuse spot in the image perceived by the user.

(8) For example, the transparent component to which the invention is applied may be an eyeglass lens, or a multilayer structure intended to be applied to such an eyeglass lens.

(9) As illustrated in FIG. 1, such a multilayer structure 10 may comprise: a transparent film 3 of polyethylene terephthalate (PET), polycarbonate (PC), or polyimide, with a thickness of 50 m (micrometers) for example, and which forms a base substrate for the structure 10; a layer 2 which covers an upper surface of the film 3; and a network of walls 1 which is formed on the layer 2, with walls 1 which extend substantially perpendicularly to the film 3.

(10) The layer 2 is preferably continuous and may be formed on the film 3 using a thin film deposition method, such as low-pressure plasma deposition or RF plasma-assisted deposition for an oxide. A sol-gel method may alternatively be used when the layer 2 consists of a hybrid material. The layer 2 may be of silica (SiO.sub.2) for example, of sufficient thickness to be continuous. The thickness of the layer 2 may be between 0.1 and 0.5 m.

(11) The walls 1 may be at least partially of an organic material, such as a resin, particularly a photoresist, each with a height h of 20 m and a thickness e that is greater than 0.1 m, preferably between 0.5 and 8 m. Two neighboring walls 1 may be separated by a distance d which is between 50 m and 1.5 mm for example, parallel to the film 3. In addition, mineral grains, such as grains of a metal oxide, may be incorporated into the resin of the walls 1, so that they are embedded in it. The resulting material constituting the walls 1 is then mineral-organic in nature.

(12) The structure 10 is transparent to light rays which propagate in the direction D perpendicular to the film 3. In particular, the film 3 and the layer 2 are individually transparent.

(13) The structure 10 then possesses an exposed surface S, formed in part by the walls 1 and in part by the layer 2 between the walls 2. The walls 1 therefore form a first portion of the surface S, denoted S.sub.1, and the portions of the layer 2 which are exposed between the walls 1 forms a second portion of the surface S, denoted S.sub.2. The material of the walls 1 constitutes the first material as designated in the general part of the present patent application, and the material of the layer 2 constitutes the second material.

(14) A dye source (not represented) is brought close to the exposed surface S. This dye source is adapted to release molecules C of at least one dye when it is heated. Such dye sources, referred to as dye sublimation sources, are well known to a person skilled in the art and it is unnecessary to further discuss their operation here. For example, the dye may be contained in a crucible arranged near the structure 10, or may be a powder or a liquid which is applied to the surface S. More generally, the invention may be applied to a mixture of multiple dyes. In this case, each dye can be transferred onto the structure 10 in the manner described, individually from a separate source or from a source of the mixture. For clarity sake, it is assumed in the following description that a single dye is used.

(15) The dye source is heated so that it releases the dye molecules C and these latter are deposited on the exposed surface S of the structure 10. The heating temperature and duration for the dye source are selected so that a sufficient quantity of dye molecules C cover the surface S in a substantially continuous and uniform manner, particularly on the sides of the walls 1 which are perpendicular to the film 3. As illustrated in FIG. 2a, dye molecules C are thus deposited at the same time on the first portion S.sub.1 and on the second portion S.sub.2 of the surface S. However, the film 3 is not in contact with the dye molecules C, as it is covered by the layer 2 between the walls 1.

(16) The dye source C is removed, then the structure 10 itself is heated, to activate a diffusion of the dye molecules C into the material of the walls 1. The temperature of the heated structure 10 may be selected to soften the resin of the walls 1. However, this heating temperature remains fairly low so that the walls 1 are not deformed. For example, the structure 10 may be heated to a temperature which is between 110 C. and 150 C. The dye molecules C then penetrate into the walls 1, from their side faces and top ends which form the surface portion S.sub.1.

(17) The material of the walls 1 was therefore selected to be permeable to the dye molecules C, in order to facilitate the diffusion of these molecules into the walls 1. The walls 1 then incorporate dye molecules C in a distribution which has the diffusion profile produced from the side and top ends of these walls (FIG. 2b).

(18) The material of the layer 2 was selected to be tight, or impermeable, to the dye molecules. Thus the dye molecules C which are present on the second surface portion S.sub.2 remain outside the layer 2 during the heating of the structure 10, without penetrating into the layer 2. In particular, the material of the layer 2 may be selected so that it is not softened by the heating of the structure 10. To this end, it has a softening temperature which is higher than that of the material of the walls 1. Thus, the film 3 remains without contact with the dye molecules C, although the constituting material of the film 3 may have an affinity for the dye used. In particular, dye molecules would diffuse into polyethylene terephthalate if the film 3 were in contact with the dye molecules C. In other words, the layer 2 constitutes an efficient barrier to protect the film 3 from the dye molecules C.

(19) During a last step which is illustrated in FIG. 2c, the structure S is rinsed with a solvent for the dye molecules C. Water may be used for this rinse, for example. The dye molecules C which remain on the exposed surface S are thus eliminated. In this manner, all the dye molecules C which are present on the second surface portion S.sub.2 are removed, so that the structure 10 is not tinted between the walls 1. Any excess dye molecules C remaining on the first surface portion S.sub.1 are removed at the same time. However, the remaining dye molecules C which had diffused into the material of the walls 1 are not in contact with the rinsing solvent, and they permanently tint the walls 1. Thus a selective tinting of the walls 1 is achieved, relative to the film 3.

(20) After the method of the invention has been applied, the structure 10 is absorbing for the light rays passing through the walls 1 and is transparent between the walls 1, with a high level of light transmission in the second surface portion S.sub.2. In particular, the final light transmission in this second surface portion S.sub.2 may be substantially equal to the initial value of the light transmission of the film 3 covered by the layer 2.

(21) In a particular application of the structure 10 tinted as described above, a transparent optical substance may then be introduced between the walls 1, up to the tops of these walls. Then a transparent sealing film 4 may be applied onto the structure 10 as represented in FIG. 3, for example by affixing it to the top ends of the walls 1. The structure 10 is thus sealed in a tight manner, and permanently contains the transparent optical substance.

(22) The structure 10 may then be applied onto an eyeglass lens 11, for example onto the convex optical face of this lens. The assembly allows providing additional functions to the final eyeglass lens 100, produced by the transparent substance. For example, this substance may be photochromic.

(23) The eyeglass lens 100 is still transparent to a light ray R.sub.1 which passes through it between two walls 1. Indeed, the ray R.sub.1 successively crosses the lens 11, the film 3, the layer 2, a portion of the optical substance which is contained between two walls 1, and the sealing film 4, which are all transparent with a high light transmission value.

(24) However, a light ray R.sub.2 which traverses the lens 100 by passing through one of the walls 1 may be deviated by the diffusion of the light, because of the small thickness e of this wall. A reduction of the lens 100 transparency would result, in the sense that was mentioned at the start of this description, providing a blurred vision for a user of this lens. But, as the material of the wall 1 has been tinted, it is absorbing so that the light intensity associated with the diffused ray R.sub.2 is low, and even very low. The ray R.sub.2 therefore does not contribute to the image formed of an object through the lens 100.

(25) By using the selective tinting method of the invention, the eyeglass lens 100 is still transparent, without a portion of the light transmitted through the lens being diffused or diffracted. The haze amount of the lens 100 can thus be less than 1%. The lens 100 therefore provides the lens user with a clear vision.