FR2702765A1

FR2702765A1 - Process for imparting to a glass article a sufficient variation in refractive index to modify the quantity of transmitted light and articles obtained by this process

Info

Publication number: FR2702765A1
Application number: FR9302997A
Authority: FR
Inventors: Solman Jean; Solman William
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-03-16
Filing date: 1993-03-16
Publication date: 1994-09-23

Abstract

Process for imparting, on microscopic scale, to a glass article, for example a sheet, a surface structure of sufficient depth to deflect all or a proportion of the luminous rays at right angles to the level of the interface between the article and the surrounding medium, so as to modify the quantity of light transmitted through the article, in punctiform zones arranged so as to form at least one pattern on a surface of the said article, characterised in that the surface of the glass article is subjected to an acid treatment by means of a solution comprising a halohydric acid, an alkaline agent in micronised state, an organic acid acting as catalyst and a quantity of water sufficient to permit a deposition of the compound salt formed in situ by the reaction between the alkaline agent and a part of the halohydric acid, after which the remainder of the halohydric acid reacts synergistically with the compound salt to impart to the surface of the article a structure consisting of a plurality of hollow zones with well-determined limits.

Description

La présente invention est du domaine de l'optique industrielle. The present invention is in the field of industrial optics.

Elle vise plus précisément un procédé destiné à modifier la texture superficielle des plaques supports ou substrats d'appareils optiques et photo-optiques à émission de radiations.It relates more precisely to a process intended to modify the surface texture of the support plates or substrates of optical and photo-optical apparatuses with radiation emission.

Jusqu'à présent, on savait modifier la texture superficielle des articles de verre, par exemple des plaques, au moyen d'une technique de sablage grâce à laquelle on pouvait obtenir, au niveau de la surface soumise au sablage, un effet de dépoli. Cette technique donne un résultat relativement grossier ne permettant pas de maitriser avec suffisamment de précision le pourcentage de lumière devant être transmise. On a également utilisé des techniques de sérigraphie ainsi que des techniques d'attaque par acides, qui ne donnent en aucun cas satisfaction. Ces dernières techniques font apparaître, au niveau de la surface des plaques, des structures en creux de formes aléatoires et disposées au hasard, ces structures se chevauchant très souvent pour former des motifs multilobés, le plus souvent bi-lobés ou tri-lobés. Until now, it has been known to modify the surface texture of glass articles, for example plates, by means of a sandblasting technique by which it is possible to obtain, on the surface subjected to sandblasting, a frosted effect. This technique gives a relatively coarse result which does not allow the percentage of light to be transmitted to be controlled with sufficient precision. Screen printing techniques as well as acid attack techniques have also been used, which are by no means satisfactory. These latter techniques reveal, at the surface of the plates, hollow structures of random shapes and arranged at random, these structures very often overlapping to form multilobed patterns, most often bi-lobed or tri-lobed.

Un objet de la présente invention est donc de fournir un procédé permettant de créer des zones à la surface d'une plaque de verrue, par exemple plaque de verre transparente d'un photocopieur , zones qui ne laissent passer que la quantité de lumière voulue en des endroits donnés, de façon à modifier la densité d'impression finale des feuilles utilisées dans un photocopieur muni d'une telle plaque modifiée. It is therefore an object of the present invention to provide a method making it possible to create zones on the surface of a wart plate, for example a transparent glass plate of a photocopier, zones which allow only the desired amount of light to pass through. of given locations, so as to modify the final printing density of the sheets used in a photocopier provided with such a modified plate.

Un autre objet de la présente invention est de permettre d'inscrire sur la plaque de verre du photocopieur tous les motifs souhaités, à savoir le logo, la raison sociale et d'autre motifs informatifs. Another object of the present invention is to make it possible to write on the glass plate of the photocopier all the desired patterns, namely the logo, the corporate name and other informative patterns.

Ainsi estampillées, les plaques de verre des photocopieurs sont personnalisées, grâce à la structure nouvelle du type matrice optique selon l'invention, augmentant ainsi l'image de marque et conduisant à réduire l'inflation de la consommation de photocopies à titre privé. Thus stamped, the glass plates of the photocopiers are personalized, thanks to the new structure of the optical matrix type according to the invention, thus increasing the brand image and leading to reducing the inflation of the consumption of photocopies for private use.

La présente invention a donc pour objet un procédé pour conférer, à l'échelle microscopique, à un article en verre, par exemple une plaque, une structure superficielle de profondeur suffisante pour dévier tout ou partie des rayons lumineux ortogonaux au niveau de l'interface entre ledit article et le milieu environnant de façon à modifier la quantité de lumière transmise à travers ledit article, en des zones ponctuelles agencées de façon à former au moins un motif sur/ou au voisinage immédiat d'une surface dudit article, ce procédé étant caractérisé en ce que l'on soumet la surface de l'article en verre à un traitement acide au moyen d'une solution comportant au moins un acide halohydrique, au moins un agent alcalin à l'état micronisé, au moins un acide-organique agissant comme catalyseur et une quantité d'eau suffisante pour permettre une déposition du sel composite formé in situ par la réaction entre l'agent alcalin et une partie de l'acide halohydrique, après quoi le reste de l'acide halohydrique agit de façon synergétique avec le sel composite pour conférer à la surface de l'article une structure constituée d'une pluralité de zones creuses aux limites bien déterminées et n'interférant pas les unes avec les autres, ces zones creuses se trouvant toutes pratiquement sur un même plan sur la surface en verre à traiter. The subject of the present invention is therefore a process for imparting, on a microscopic scale, to a glass article, for example a plate, a surface structure of sufficient depth to deflect all or part of the orthogonal light rays at the interface. between said article and the surrounding medium so as to modify the amount of light transmitted through said article, in point zones arranged so as to form at least one pattern on / or in the immediate vicinity of a surface of said article, this method being characterized in that the surface of the glass article is subjected to an acid treatment by means of a solution comprising at least one hydrohalic acid, at least one alkaline agent in the micronized state, at least one organic acid acting as a catalyst and a sufficient amount of water to allow deposition of the composite salt formed in situ by the reaction between the alkaline agent and part of the hydrohalic acid , after which the remainder of the hydrohalic acid acts synergistically with the composite salt to give the surface of the article a structure made up of a plurality of hollow zones with well-defined limits and which do not interfere with each other. others, these hollow zones all being practically on the same plane on the glass surface to be treated.

Le procédé selon l'invention est en outre remarquable par les points suivants - l'acide halohydrique est l'acide fluorydrique - l'agent alcalin est constitué par des cristaux de soude - l'acide organique est de l'acide acétique. The process according to the invention is further remarkable by the following points - the hydrohalic acid is fluororyric acid - the alkaline agent consists of sodium hydroxide crystals - the organic acid is acetic acid.

L'invention vise également les plaques de verre, utilisées comme supports ou substrats dans les appareils à émission de radiation, obtenus par le procédé tel que. spécifié ci-dessus. The invention also relates to glass plates, used as supports or substrates in radiation emission devices, obtained by the process such as. specified above.

D'autres caractéristiques et avantages de la présente invention apparaitront à la lecture d'un exemple de réalisation ci-dessous, donné à titre uniquement illustratif, en se référant aux dessins annexés dont la figure 1 représente un mode de réalisation selon la présente invention. Other characteristics and advantages of the present invention will appear on reading an exemplary embodiment below, given by way of illustration only, with reference to the appended drawings, FIG. 1 of which represents an embodiment according to the present invention.

Sur la plaque de verre (4) de la figure I, qui est préalablement pourvue de caches non représentés aux dessins, qui laissent apparaitre le motif désiré, on applique une solution constituée de 102 g d'acide fluorydrique à 40 %, de 90 g de cristaux de carbonate de soude micronisés dont la dimension moyenne se situe dans la gamme de deux à quatre microns, de 81 g d'acide acétique, agissant comme catalyseur, et 705 g d'eau pendant une période de 10 à 25 mn avec une épaisseur de solution de 10 à 20 mm, de préférence 15 mm. On obtient ainsi un liquide blanc turbide dans lequel se forme in situ un sel composite constitué par du carbonate de sodium déca-hydraté sur lequel vient se lier une partie de l'acide fluorydrique, grâce à l'action catalytique de l'acide acétique. On the glass plate (4) of Figure I, which is previously provided with covers not shown in the drawings, which reveal the desired pattern, applying a solution consisting of 102 g of 40% fluororyric acid, 90 g micronized sodium carbonate crystals whose average size is in the range of two to four microns, 81 g of acetic acid, acting as a catalyst, and 705 g of water for a period of 10 to 25 min with a thickness of solution from 10 to 20 mm, preferably 15 mm. A turbid white liquid is thus obtained in which a composite salt is formed in situ consisting of deca-hydrated sodium carbonate on which part of the fluoridric acid is bound, thanks to the catalytic action of acetic acid.

Les cristaux micronisés (3) de sel composite ainsi formés se déposent sur la surface de la plaque de verre (4) créant ainsi des espaces (5) entre eux, qui laissent passer l'acide fluorydrique restant, c'est-à dire 2/3 de la quantité initiale sur des surfaces extrêment faibles. The micronized crystals (3) of composite salt thus formed are deposited on the surface of the glass plate (4) thus creating spaces (5) between them, which allow the remaining fluoridric acid to pass, that is to say 2 / 3 of the initial quantity on extremely small surfaces.

Chaque point attaqué par l'action synergétique du sel composite et de l'acide fluorydrique restant, va former une micro-lentille (1, 2) dont on pourra faire varier la forme selon que l'on désire une réfraction plus ou moins importante en faisant varier le temps de pose ou l'épaisseur du sel composite.Each point attacked by the synergistic action of the composite salt and the remaining hydrorydric acid, will form a microlens (1, 2) whose shape can be varied according to whether a more or less significant refraction is desired. varying the exposure time or the thickness of the composite salt.

Une fois le temps de traitement terminé, on élimine la solution et on laisse la- plaque de verre sécher, après quoi on examine au microscope les zones non revêtues de caches. On observe l'apparition de zones ponctuelles constituées par des micro-lentilles (figure 1) qui, lors du montage de la plaque sur le photocopieur, feront varier, du fait à la fois de leur forme et de leur constitution réfractométrique différente (1, 2), le taux de transmission de la lumière à travers la plaque ce qui se traduira par des zones plus ou moins sombres sur la feuille utilisée. When the treatment time has ended, the solution is removed and the glass plate is left to dry, after which the areas not covered with covers are examined under a microscope. One observes the appearance of specific zones constituted by micro-lenses (figure 1) which, during the mounting of the plate on the photocopier, will vary, due to both their shape and their different refractometric constitution (1, 2), the rate of light transmission through the plate which will result in more or less dark areas on the sheet used.

Il est clair que l'invention n'est nullement limitée à l'exemple de réalisation décrit ci-dessus mais englobe toutes les modifications et variantes à la portée de l'homme de l'art. C'est ainsi que l'on peut obtenir, par le procédé selon l'invention, des matrices optiques constituées chacune d'un substrat en verre, qui présente sur tout ou une partie d'une de ses surfaces, une texture se prolongeant uniformément dans un plan et constituée de structures microscopiques de forme lenticullaire, bien déterminées et n'interférant pas les unes avec les autres. It is clear that the invention is in no way limited to the embodiment described above but encompasses all the modifications and variants within the reach of ordinary skill in the art. Thus it is possible to obtain, by the method according to the invention, optical matrices each consisting of a glass substrate, which has on all or part of one of its surfaces, a texture extending uniformly in a plane and made up of microscopic structures of lenticular form, well defined and not interfering with each other.

Claims

l) Method for imparting, on a microscopic scale, to a glass article, for example a plate, a surface structure of sufficient depth to deflect all or part of the orthogonal light rays at the interface between said article and the medium surrounding so as to modify the quantity of light transmitted through said article, in point zones arranged so as to form at least one pattern on / or in the immediate vicinity of a surface of said article, this method being characterized in that the the surface of the glass article is subjected to an acid treatment by means of a solution comprising at least one hydrohalic acid, at least one alkaline agent in the micronized state, at least one organic acid acting as catalyst and a quantity of water sufficient to allow deposition of the composite salt formed in situ by the reaction between the alkaline agent and part of the hydrohalic acid, after which the rest of the halohydr acid it acts synergistically with the composite salt to give the surface of the article a structure made up of a plurality of hollow zones with well-defined limits and which do not interfere with each other, these hollow zones all being practically on the same plane on the glass surface to be treated.

2) Method according to claim 1, characterized in that the hydrohalic acid is fluororydric acid.

3) Method according to claim 1, characterized in that the alkaline agent consists of deca-hydrated sodium carbonate.

4) Method according to claim 1, characterized in that the organic acid serving as catalyst is acetic acid.

5) Method according to claim 1, characterized in that one treats a glass plate previously provided with covers revealing the desired pattern by means of a solution consisting of 102 g of 40% fluororyric acid, 90 g of deca-hydrated sodium carbonate crystals, 80 g of acetic acid acting as a catalyst in the formation of the composite salt, and 705 g of water, for a period of 10 to 25 minutes, with a thickness of solution of 10 to 20 mm, preferably 15 mm.

6) Method according to claim 5, characterized in that the deca-hydrated sodium carbonate crystals have an average size in the range of 2 to 4 microns.

7) Method according to any one of claims 1 to 6, characterized in that the point areas obtained on the glass surface to be treated are constituted by structures of microlenticullary forms.

8) Plates used as supports or substrates in radiation-emitting devices, obtained by the method according to any one of claims 1 to 7.

9) Optical matrix obtained by the method according to any one of claims l to 7 and consisting of a glass substrate, which has on all or part of one of its surfaces, a texture extending uniformly in one plane and made up of microscopic structures of lenticullary shape, well determined and not interfering with each other.